89 files changed, 42177 insertions, 0 deletions

diff --git a/venv/lib/python3.9/site-packages/tornado/__init__.py b/venv/lib/python3.9/site-packages/tornado/__init__.py
new file mode 100644
index 00000000..afbd7150
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/__init__.py
@@ -0,0 +1,67 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""The Tornado web server and tools."""
+
+# version is a human-readable version number.
+
+# version_info is a four-tuple for programmatic comparison. The first
+# three numbers are the components of the version number.  The fourth
+# is zero for an official release, positive for a development branch,
+# or negative for a release candidate or beta (after the base version
+# number has been incremented)
+version = "6.3.1"
+version_info = (6, 3, 1, 0)
+
+import importlib
+import typing
+
+__all__ = [
+    "auth",
+    "autoreload",
+    "concurrent",
+    "curl_httpclient",
+    "escape",
+    "gen",
+    "http1connection",
+    "httpclient",
+    "httpserver",
+    "httputil",
+    "ioloop",
+    "iostream",
+    "locale",
+    "locks",
+    "log",
+    "netutil",
+    "options",
+    "platform",
+    "process",
+    "queues",
+    "routing",
+    "simple_httpclient",
+    "tcpclient",
+    "tcpserver",
+    "template",
+    "testing",
+    "util",
+    "web",
+]
+
+
+# Copied from https://peps.python.org/pep-0562/
+def __getattr__(name: str) -> typing.Any:
+    if name in __all__:
+        return importlib.import_module("." + name, __name__)
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
diff --git a/venv/lib/python3.9/site-packages/tornado/_locale_data.py b/venv/lib/python3.9/site-packages/tornado/_locale_data.py
new file mode 100644
index 00000000..7a5d2852
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/_locale_data.py
@@ -0,0 +1,80 @@
+# Copyright 2012 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Data used by the tornado.locale module."""
+
+LOCALE_NAMES = {
+    "af_ZA": {"name_en": "Afrikaans", "name": "Afrikaans"},
+    "am_ET": {"name_en": "Amharic", "name": "አማርኛ"},
+    "ar_AR": {"name_en": "Arabic", "name": "العربية"},
+    "bg_BG": {"name_en": "Bulgarian", "name": "Български"},
+    "bn_IN": {"name_en": "Bengali", "name": "বাংলা"},
+    "bs_BA": {"name_en": "Bosnian", "name": "Bosanski"},
+    "ca_ES": {"name_en": "Catalan", "name": "Català"},
+    "cs_CZ": {"name_en": "Czech", "name": "Čeština"},
+    "cy_GB": {"name_en": "Welsh", "name": "Cymraeg"},
+    "da_DK": {"name_en": "Danish", "name": "Dansk"},
+    "de_DE": {"name_en": "German", "name": "Deutsch"},
+    "el_GR": {"name_en": "Greek", "name": "Ελληνικά"},
+    "en_GB": {"name_en": "English (UK)", "name": "English (UK)"},
+    "en_US": {"name_en": "English (US)", "name": "English (US)"},
+    "es_ES": {"name_en": "Spanish (Spain)", "name": "Español (España)"},
+    "es_LA": {"name_en": "Spanish", "name": "Español"},
+    "et_EE": {"name_en": "Estonian", "name": "Eesti"},
+    "eu_ES": {"name_en": "Basque", "name": "Euskara"},
+    "fa_IR": {"name_en": "Persian", "name": "فارسی"},
+    "fi_FI": {"name_en": "Finnish", "name": "Suomi"},
+    "fr_CA": {"name_en": "French (Canada)", "name": "Français (Canada)"},
+    "fr_FR": {"name_en": "French", "name": "Français"},
+    "ga_IE": {"name_en": "Irish", "name": "Gaeilge"},
+    "gl_ES": {"name_en": "Galician", "name": "Galego"},
+    "he_IL": {"name_en": "Hebrew", "name": "עברית"},
+    "hi_IN": {"name_en": "Hindi", "name": "हिन्दी"},
+    "hr_HR": {"name_en": "Croatian", "name": "Hrvatski"},
+    "hu_HU": {"name_en": "Hungarian", "name": "Magyar"},
+    "id_ID": {"name_en": "Indonesian", "name": "Bahasa Indonesia"},
+    "is_IS": {"name_en": "Icelandic", "name": "Íslenska"},
+    "it_IT": {"name_en": "Italian", "name": "Italiano"},
+    "ja_JP": {"name_en": "Japanese", "name": "日本語"},
+    "ko_KR": {"name_en": "Korean", "name": "한국어"},
+    "lt_LT": {"name_en": "Lithuanian", "name": "Lietuvių"},
+    "lv_LV": {"name_en": "Latvian", "name": "Latviešu"},
+    "mk_MK": {"name_en": "Macedonian", "name": "Македонски"},
+    "ml_IN": {"name_en": "Malayalam", "name": "മലയാളം"},
+    "ms_MY": {"name_en": "Malay", "name": "Bahasa Melayu"},
+    "nb_NO": {"name_en": "Norwegian (bokmal)", "name": "Norsk (bokmål)"},
+    "nl_NL": {"name_en": "Dutch", "name": "Nederlands"},
+    "nn_NO": {"name_en": "Norwegian (nynorsk)", "name": "Norsk (nynorsk)"},
+    "pa_IN": {"name_en": "Punjabi", "name": "ਪੰਜਾਬੀ"},
+    "pl_PL": {"name_en": "Polish", "name": "Polski"},
+    "pt_BR": {"name_en": "Portuguese (Brazil)", "name": "Português (Brasil)"},
+    "pt_PT": {"name_en": "Portuguese (Portugal)", "name": "Português (Portugal)"},
+    "ro_RO": {"name_en": "Romanian", "name": "Română"},
+    "ru_RU": {"name_en": "Russian", "name": "Русский"},
+    "sk_SK": {"name_en": "Slovak", "name": "Slovenčina"},
+    "sl_SI": {"name_en": "Slovenian", "name": "Slovenščina"},
+    "sq_AL": {"name_en": "Albanian", "name": "Shqip"},
+    "sr_RS": {"name_en": "Serbian", "name": "Српски"},
+    "sv_SE": {"name_en": "Swedish", "name": "Svenska"},
+    "sw_KE": {"name_en": "Swahili", "name": "Kiswahili"},
+    "ta_IN": {"name_en": "Tamil", "name": "தமிழ்"},
+    "te_IN": {"name_en": "Telugu", "name": "తెలుగు"},
+    "th_TH": {"name_en": "Thai", "name": "ภาษาไทย"},
+    "tl_PH": {"name_en": "Filipino", "name": "Filipino"},
+    "tr_TR": {"name_en": "Turkish", "name": "Türkçe"},
+    "uk_UA": {"name_en": "Ukraini ", "name": "Українська"},
+    "vi_VN": {"name_en": "Vietnamese", "name": "Tiếng Việt"},
+    "zh_CN": {"name_en": "Chinese (Simplified)", "name": "中文(简体)"},
+    "zh_TW": {"name_en": "Chinese (Traditional)", "name": "中文(繁體)"},
+}
diff --git a/venv/lib/python3.9/site-packages/tornado/auth.py b/venv/lib/python3.9/site-packages/tornado/auth.py
new file mode 100644
index 00000000..59501f56
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/auth.py
@@ -0,0 +1,1212 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""This module contains implementations of various third-party
+authentication schemes.
+
+All the classes in this file are class mixins designed to be used with
+the `tornado.web.RequestHandler` class.  They are used in two ways:
+
+* On a login handler, use methods such as ``authenticate_redirect()``,
+  ``authorize_redirect()``, and ``get_authenticated_user()`` to
+  establish the user's identity and store authentication tokens to your
+  database and/or cookies.
+* In non-login handlers, use methods such as ``facebook_request()``
+  or ``twitter_request()`` to use the authentication tokens to make
+  requests to the respective services.
+
+They all take slightly different arguments due to the fact all these
+services implement authentication and authorization slightly differently.
+See the individual service classes below for complete documentation.
+
+Example usage for Google OAuth:
+
+.. testcode::
+
+    class GoogleOAuth2LoginHandler(tornado.web.RequestHandler,
+                                   tornado.auth.GoogleOAuth2Mixin):
+        async def get(self):
+            if self.get_argument('code', False):
+                user = await self.get_authenticated_user(
+                    redirect_uri='http://your.site.com/auth/google',
+                    code=self.get_argument('code'))
+                # Save the user with e.g. set_signed_cookie
+            else:
+                self.authorize_redirect(
+                    redirect_uri='http://your.site.com/auth/google',
+                    client_id=self.settings['google_oauth']['key'],
+                    scope=['profile', 'email'],
+                    response_type='code',
+                    extra_params={'approval_prompt': 'auto'})
+
+.. testoutput::
+   :hide:
+
+"""
+
+import base64
+import binascii
+import hashlib
+import hmac
+import time
+import urllib.parse
+import uuid
+
+from tornado import httpclient
+from tornado import escape
+from tornado.httputil import url_concat
+from tornado.util import unicode_type
+from tornado.web import RequestHandler
+
+from typing import List, Any, Dict, cast, Iterable, Union, Optional
+
+
+class AuthError(Exception):
+    pass
+
+
+class OpenIdMixin(object):
+    """Abstract implementation of OpenID and Attribute Exchange.
+
+    Class attributes:
+
+    * ``_OPENID_ENDPOINT``: the identity provider's URI.
+    """
+
+    def authenticate_redirect(
+        self,
+        callback_uri: Optional[str] = None,
+        ax_attrs: List[str] = ["name", "email", "language", "username"],
+    ) -> None:
+        """Redirects to the authentication URL for this service.
+
+        After authentication, the service will redirect back to the given
+        callback URI with additional parameters including ``openid.mode``.
+
+        We request the given attributes for the authenticated user by
+        default (name, email, language, and username). If you don't need
+        all those attributes for your app, you can request fewer with
+        the ax_attrs keyword argument.
+
+        .. versionchanged:: 6.0
+
+            The ``callback`` argument was removed and this method no
+            longer returns an awaitable object. It is now an ordinary
+            synchronous function.
+        """
+        handler = cast(RequestHandler, self)
+        callback_uri = callback_uri or handler.request.uri
+        assert callback_uri is not None
+        args = self._openid_args(callback_uri, ax_attrs=ax_attrs)
+        endpoint = self._OPENID_ENDPOINT  # type: ignore
+        handler.redirect(endpoint + "?" + urllib.parse.urlencode(args))
+
+    async def get_authenticated_user(
+        self, http_client: Optional[httpclient.AsyncHTTPClient] = None
+    ) -> Dict[str, Any]:
+        """Fetches the authenticated user data upon redirect.
+
+        This method should be called by the handler that receives the
+        redirect from the `authenticate_redirect()` method (which is
+        often the same as the one that calls it; in that case you would
+        call `get_authenticated_user` if the ``openid.mode`` parameter
+        is present and `authenticate_redirect` if it is not).
+
+        The result of this method will generally be used to set a cookie.
+
+        .. versionchanged:: 6.0
+
+            The ``callback`` argument was removed. Use the returned
+            awaitable object instead.
+        """
+        handler = cast(RequestHandler, self)
+        # Verify the OpenID response via direct request to the OP
+        args = dict(
+            (k, v[-1]) for k, v in handler.request.arguments.items()
+        )  # type: Dict[str, Union[str, bytes]]
+        args["openid.mode"] = "check_authentication"
+        url = self._OPENID_ENDPOINT  # type: ignore
+        if http_client is None:
+            http_client = self.get_auth_http_client()
+        resp = await http_client.fetch(
+            url, method="POST", body=urllib.parse.urlencode(args)
+        )
+        return self._on_authentication_verified(resp)
+
+    def _openid_args(
+        self,
+        callback_uri: str,
+        ax_attrs: Iterable[str] = [],
+        oauth_scope: Optional[str] = None,
+    ) -> Dict[str, str]:
+        handler = cast(RequestHandler, self)
+        url = urllib.parse.urljoin(handler.request.full_url(), callback_uri)
+        args = {
+            "openid.ns": "http://specs.openid.net/auth/2.0",
+            "openid.claimed_id": "http://specs.openid.net/auth/2.0/identifier_select",
+            "openid.identity": "http://specs.openid.net/auth/2.0/identifier_select",
+            "openid.return_to": url,
+            "openid.realm": urllib.parse.urljoin(url, "/"),
+            "openid.mode": "checkid_setup",
+        }
+        if ax_attrs:
+            args.update(
+                {
+                    "openid.ns.ax": "http://openid.net/srv/ax/1.0",
+                    "openid.ax.mode": "fetch_request",
+                }
+            )
+            ax_attrs = set(ax_attrs)
+            required = []  # type: List[str]
+            if "name" in ax_attrs:
+                ax_attrs -= set(["name", "firstname", "fullname", "lastname"])
+                required += ["firstname", "fullname", "lastname"]
+                args.update(
+                    {
+                        "openid.ax.type.firstname": "http://axschema.org/namePerson/first",
+                        "openid.ax.type.fullname": "http://axschema.org/namePerson",
+                        "openid.ax.type.lastname": "http://axschema.org/namePerson/last",
+                    }
+                )
+            known_attrs = {
+                "email": "http://axschema.org/contact/email",
+                "language": "http://axschema.org/pref/language",
+                "username": "http://axschema.org/namePerson/friendly",
+            }
+            for name in ax_attrs:
+                args["openid.ax.type." + name] = known_attrs[name]
+                required.append(name)
+            args["openid.ax.required"] = ",".join(required)
+        if oauth_scope:
+            args.update(
+                {
+                    "openid.ns.oauth": "http://specs.openid.net/extensions/oauth/1.0",
+                    "openid.oauth.consumer": handler.request.host.split(":")[0],
+                    "openid.oauth.scope": oauth_scope,
+                }
+            )
+        return args
+
+    def _on_authentication_verified(
+        self, response: httpclient.HTTPResponse
+    ) -> Dict[str, Any]:
+        handler = cast(RequestHandler, self)
+        if b"is_valid:true" not in response.body:
+            raise AuthError("Invalid OpenID response: %r" % response.body)
+
+        # Make sure we got back at least an email from attribute exchange
+        ax_ns = None
+        for key in handler.request.arguments:
+            if (
+                key.startswith("openid.ns.")
+                and handler.get_argument(key) == "http://openid.net/srv/ax/1.0"
+            ):
+                ax_ns = key[10:]
+                break
+
+        def get_ax_arg(uri: str) -> str:
+            if not ax_ns:
+                return ""
+            prefix = "openid." + ax_ns + ".type."
+            ax_name = None
+            for name in handler.request.arguments.keys():
+                if handler.get_argument(name) == uri and name.startswith(prefix):
+                    part = name[len(prefix) :]
+                    ax_name = "openid." + ax_ns + ".value." + part
+                    break
+            if not ax_name:
+                return ""
+            return handler.get_argument(ax_name, "")
+
+        email = get_ax_arg("http://axschema.org/contact/email")
+        name = get_ax_arg("http://axschema.org/namePerson")
+        first_name = get_ax_arg("http://axschema.org/namePerson/first")
+        last_name = get_ax_arg("http://axschema.org/namePerson/last")
+        username = get_ax_arg("http://axschema.org/namePerson/friendly")
+        locale = get_ax_arg("http://axschema.org/pref/language").lower()
+        user = dict()
+        name_parts = []
+        if first_name:
+            user["first_name"] = first_name
+            name_parts.append(first_name)
+        if last_name:
+            user["last_name"] = last_name
+            name_parts.append(last_name)
+        if name:
+            user["name"] = name
+        elif name_parts:
+            user["name"] = " ".join(name_parts)
+        elif email:
+            user["name"] = email.split("@")[0]
+        if email:
+            user["email"] = email
+        if locale:
+            user["locale"] = locale
+        if username:
+            user["username"] = username
+        claimed_id = handler.get_argument("openid.claimed_id", None)
+        if claimed_id:
+            user["claimed_id"] = claimed_id
+        return user
+
+    def get_auth_http_client(self) -> httpclient.AsyncHTTPClient:
+        """Returns the `.AsyncHTTPClient` instance to be used for auth requests.
+
+        May be overridden by subclasses to use an HTTP client other than
+        the default.
+        """
+        return httpclient.AsyncHTTPClient()
+
+
+class OAuthMixin(object):
+    """Abstract implementation of OAuth 1.0 and 1.0a.
+
+    See `TwitterMixin` below for an example implementation.
+
+    Class attributes:
+
+    * ``_OAUTH_AUTHORIZE_URL``: The service's OAuth authorization url.
+    * ``_OAUTH_ACCESS_TOKEN_URL``: The service's OAuth access token url.
+    * ``_OAUTH_VERSION``: May be either "1.0" or "1.0a".
+    * ``_OAUTH_NO_CALLBACKS``: Set this to True if the service requires
+      advance registration of callbacks.
+
+    Subclasses must also override the `_oauth_get_user_future` and
+    `_oauth_consumer_token` methods.
+    """
+
+    async def authorize_redirect(
+        self,
+        callback_uri: Optional[str] = None,
+        extra_params: Optional[Dict[str, Any]] = None,
+        http_client: Optional[httpclient.AsyncHTTPClient] = None,
+    ) -> None:
+        """Redirects the user to obtain OAuth authorization for this service.
+
+        The ``callback_uri`` may be omitted if you have previously
+        registered a callback URI with the third-party service. For
+        some services, you must use a previously-registered callback
+        URI and cannot specify a callback via this method.
+
+        This method sets a cookie called ``_oauth_request_token`` which is
+        subsequently used (and cleared) in `get_authenticated_user` for
+        security purposes.
+
+        This method is asynchronous and must be called with ``await``
+        or ``yield`` (This is different from other ``auth*_redirect``
+        methods defined in this module). It calls
+        `.RequestHandler.finish` for you so you should not write any
+        other response after it returns.
+
+        .. versionchanged:: 3.1
+           Now returns a `.Future` and takes an optional callback, for
+           compatibility with `.gen.coroutine`.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           awaitable object instead.
+
+        """
+        if callback_uri and getattr(self, "_OAUTH_NO_CALLBACKS", False):
+            raise Exception("This service does not support oauth_callback")
+        if http_client is None:
+            http_client = self.get_auth_http_client()
+        assert http_client is not None
+        if getattr(self, "_OAUTH_VERSION", "1.0a") == "1.0a":
+            response = await http_client.fetch(
+                self._oauth_request_token_url(
+                    callback_uri=callback_uri, extra_params=extra_params
+                )
+            )
+        else:
+            response = await http_client.fetch(self._oauth_request_token_url())
+        url = self._OAUTH_AUTHORIZE_URL  # type: ignore
+        self._on_request_token(url, callback_uri, response)
+
+    async def get_authenticated_user(
+        self, http_client: Optional[httpclient.AsyncHTTPClient] = None
+    ) -> Dict[str, Any]:
+        """Gets the OAuth authorized user and access token.
+
+        This method should be called from the handler for your
+        OAuth callback URL to complete the registration process. We run the
+        callback with the authenticated user dictionary.  This dictionary
+        will contain an ``access_key`` which can be used to make authorized
+        requests to this service on behalf of the user.  The dictionary will
+        also contain other fields such as ``name``, depending on the service
+        used.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           awaitable object instead.
+        """
+        handler = cast(RequestHandler, self)
+        request_key = escape.utf8(handler.get_argument("oauth_token"))
+        oauth_verifier = handler.get_argument("oauth_verifier", None)
+        request_cookie = handler.get_cookie("_oauth_request_token")
+        if not request_cookie:
+            raise AuthError("Missing OAuth request token cookie")
+        handler.clear_cookie("_oauth_request_token")
+        cookie_key, cookie_secret = [
+            base64.b64decode(escape.utf8(i)) for i in request_cookie.split("|")
+        ]
+        if cookie_key != request_key:
+            raise AuthError("Request token does not match cookie")
+        token = dict(
+            key=cookie_key, secret=cookie_secret
+        )  # type: Dict[str, Union[str, bytes]]
+        if oauth_verifier:
+            token["verifier"] = oauth_verifier
+        if http_client is None:
+            http_client = self.get_auth_http_client()
+        assert http_client is not None
+        response = await http_client.fetch(self._oauth_access_token_url(token))
+        access_token = _oauth_parse_response(response.body)
+        user = await self._oauth_get_user_future(access_token)
+        if not user:
+            raise AuthError("Error getting user")
+        user["access_token"] = access_token
+        return user
+
+    def _oauth_request_token_url(
+        self,
+        callback_uri: Optional[str] = None,
+        extra_params: Optional[Dict[str, Any]] = None,
+    ) -> str:
+        handler = cast(RequestHandler, self)
+        consumer_token = self._oauth_consumer_token()
+        url = self._OAUTH_REQUEST_TOKEN_URL  # type: ignore
+        args = dict(
+            oauth_consumer_key=escape.to_basestring(consumer_token["key"]),
+            oauth_signature_method="HMAC-SHA1",
+            oauth_timestamp=str(int(time.time())),
+            oauth_nonce=escape.to_basestring(binascii.b2a_hex(uuid.uuid4().bytes)),
+            oauth_version="1.0",
+        )
+        if getattr(self, "_OAUTH_VERSION", "1.0a") == "1.0a":
+            if callback_uri == "oob":
+                args["oauth_callback"] = "oob"
+            elif callback_uri:
+                args["oauth_callback"] = urllib.parse.urljoin(
+                    handler.request.full_url(), callback_uri
+                )
+            if extra_params:
+                args.update(extra_params)
+            signature = _oauth10a_signature(consumer_token, "GET", url, args)
+        else:
+            signature = _oauth_signature(consumer_token, "GET", url, args)
+
+        args["oauth_signature"] = signature
+        return url + "?" + urllib.parse.urlencode(args)
+
+    def _on_request_token(
+        self,
+        authorize_url: str,
+        callback_uri: Optional[str],
+        response: httpclient.HTTPResponse,
+    ) -> None:
+        handler = cast(RequestHandler, self)
+        request_token = _oauth_parse_response(response.body)
+        data = (
+            base64.b64encode(escape.utf8(request_token["key"]))
+            + b"|"
+            + base64.b64encode(escape.utf8(request_token["secret"]))
+        )
+        handler.set_cookie("_oauth_request_token", data)
+        args = dict(oauth_token=request_token["key"])
+        if callback_uri == "oob":
+            handler.finish(authorize_url + "?" + urllib.parse.urlencode(args))
+            return
+        elif callback_uri:
+            args["oauth_callback"] = urllib.parse.urljoin(
+                handler.request.full_url(), callback_uri
+            )
+        handler.redirect(authorize_url + "?" + urllib.parse.urlencode(args))
+
+    def _oauth_access_token_url(self, request_token: Dict[str, Any]) -> str:
+        consumer_token = self._oauth_consumer_token()
+        url = self._OAUTH_ACCESS_TOKEN_URL  # type: ignore
+        args = dict(
+            oauth_consumer_key=escape.to_basestring(consumer_token["key"]),
+            oauth_token=escape.to_basestring(request_token["key"]),
+            oauth_signature_method="HMAC-SHA1",
+            oauth_timestamp=str(int(time.time())),
+            oauth_nonce=escape.to_basestring(binascii.b2a_hex(uuid.uuid4().bytes)),
+            oauth_version="1.0",
+        )
+        if "verifier" in request_token:
+            args["oauth_verifier"] = request_token["verifier"]
+
+        if getattr(self, "_OAUTH_VERSION", "1.0a") == "1.0a":
+            signature = _oauth10a_signature(
+                consumer_token, "GET", url, args, request_token
+            )
+        else:
+            signature = _oauth_signature(
+                consumer_token, "GET", url, args, request_token
+            )
+
+        args["oauth_signature"] = signature
+        return url + "?" + urllib.parse.urlencode(args)
+
+    def _oauth_consumer_token(self) -> Dict[str, Any]:
+        """Subclasses must override this to return their OAuth consumer keys.
+
+        The return value should be a `dict` with keys ``key`` and ``secret``.
+        """
+        raise NotImplementedError()
+
+    async def _oauth_get_user_future(
+        self, access_token: Dict[str, Any]
+    ) -> Dict[str, Any]:
+        """Subclasses must override this to get basic information about the
+        user.
+
+        Should be a coroutine whose result is a dictionary
+        containing information about the user, which may have been
+        retrieved by using ``access_token`` to make a request to the
+        service.
+
+        The access token will be added to the returned dictionary to make
+        the result of `get_authenticated_user`.
+
+        .. versionchanged:: 5.1
+
+           Subclasses may also define this method with ``async def``.
+
+        .. versionchanged:: 6.0
+
+           A synchronous fallback to ``_oauth_get_user`` was removed.
+        """
+        raise NotImplementedError()
+
+    def _oauth_request_parameters(
+        self,
+        url: str,
+        access_token: Dict[str, Any],
+        parameters: Dict[str, Any] = {},
+        method: str = "GET",
+    ) -> Dict[str, Any]:
+        """Returns the OAuth parameters as a dict for the given request.
+
+        parameters should include all POST arguments and query string arguments
+        that will be sent with the request.
+        """
+        consumer_token = self._oauth_consumer_token()
+        base_args = dict(
+            oauth_consumer_key=escape.to_basestring(consumer_token["key"]),
+            oauth_token=escape.to_basestring(access_token["key"]),
+            oauth_signature_method="HMAC-SHA1",
+            oauth_timestamp=str(int(time.time())),
+            oauth_nonce=escape.to_basestring(binascii.b2a_hex(uuid.uuid4().bytes)),
+            oauth_version="1.0",
+        )
+        args = {}
+        args.update(base_args)
+        args.update(parameters)
+        if getattr(self, "_OAUTH_VERSION", "1.0a") == "1.0a":
+            signature = _oauth10a_signature(
+                consumer_token, method, url, args, access_token
+            )
+        else:
+            signature = _oauth_signature(
+                consumer_token, method, url, args, access_token
+            )
+        base_args["oauth_signature"] = escape.to_basestring(signature)
+        return base_args
+
+    def get_auth_http_client(self) -> httpclient.AsyncHTTPClient:
+        """Returns the `.AsyncHTTPClient` instance to be used for auth requests.
+
+        May be overridden by subclasses to use an HTTP client other than
+        the default.
+        """
+        return httpclient.AsyncHTTPClient()
+
+
+class OAuth2Mixin(object):
+    """Abstract implementation of OAuth 2.0.
+
+    See `FacebookGraphMixin` or `GoogleOAuth2Mixin` below for example
+    implementations.
+
+    Class attributes:
+
+    * ``_OAUTH_AUTHORIZE_URL``: The service's authorization url.
+    * ``_OAUTH_ACCESS_TOKEN_URL``:  The service's access token url.
+    """
+
+    def authorize_redirect(
+        self,
+        redirect_uri: Optional[str] = None,
+        client_id: Optional[str] = None,
+        client_secret: Optional[str] = None,
+        extra_params: Optional[Dict[str, Any]] = None,
+        scope: Optional[List[str]] = None,
+        response_type: str = "code",
+    ) -> None:
+        """Redirects the user to obtain OAuth authorization for this service.
+
+        Some providers require that you register a redirect URL with
+        your application instead of passing one via this method. You
+        should call this method to log the user in, and then call
+        ``get_authenticated_user`` in the handler for your
+        redirect URL to complete the authorization process.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument and returned awaitable were removed;
+           this is now an ordinary synchronous function.
+        """
+        handler = cast(RequestHandler, self)
+        args = {"response_type": response_type}
+        if redirect_uri is not None:
+            args["redirect_uri"] = redirect_uri
+        if client_id is not None:
+            args["client_id"] = client_id
+        if extra_params:
+            args.update(extra_params)
+        if scope:
+            args["scope"] = " ".join(scope)
+        url = self._OAUTH_AUTHORIZE_URL  # type: ignore
+        handler.redirect(url_concat(url, args))
+
+    def _oauth_request_token_url(
+        self,
+        redirect_uri: Optional[str] = None,
+        client_id: Optional[str] = None,
+        client_secret: Optional[str] = None,
+        code: Optional[str] = None,
+        extra_params: Optional[Dict[str, Any]] = None,
+    ) -> str:
+        url = self._OAUTH_ACCESS_TOKEN_URL  # type: ignore
+        args = {}  # type: Dict[str, str]
+        if redirect_uri is not None:
+            args["redirect_uri"] = redirect_uri
+        if code is not None:
+            args["code"] = code
+        if client_id is not None:
+            args["client_id"] = client_id
+        if client_secret is not None:
+            args["client_secret"] = client_secret
+        if extra_params:
+            args.update(extra_params)
+        return url_concat(url, args)
+
+    async def oauth2_request(
+        self,
+        url: str,
+        access_token: Optional[str] = None,
+        post_args: Optional[Dict[str, Any]] = None,
+        **args: Any
+    ) -> Any:
+        """Fetches the given URL auth an OAuth2 access token.
+
+        If the request is a POST, ``post_args`` should be provided. Query
+        string arguments should be given as keyword arguments.
+
+        Example usage:
+
+        ..testcode::
+
+            class MainHandler(tornado.web.RequestHandler,
+                              tornado.auth.FacebookGraphMixin):
+                @tornado.web.authenticated
+                async def get(self):
+                    new_entry = await self.oauth2_request(
+                        "https://graph.facebook.com/me/feed",
+                        post_args={"message": "I am posting from my Tornado application!"},
+                        access_token=self.current_user["access_token"])
+
+                    if not new_entry:
+                        # Call failed; perhaps missing permission?
+                        self.authorize_redirect()
+                        return
+                    self.finish("Posted a message!")
+
+        .. testoutput::
+           :hide:
+
+        .. versionadded:: 4.3
+
+        .. versionchanged::: 6.0
+
+           The ``callback`` argument was removed. Use the returned awaitable object instead.
+        """
+        all_args = {}
+        if access_token:
+            all_args["access_token"] = access_token
+            all_args.update(args)
+
+        if all_args:
+            url += "?" + urllib.parse.urlencode(all_args)
+        http = self.get_auth_http_client()
+        if post_args is not None:
+            response = await http.fetch(
+                url, method="POST", body=urllib.parse.urlencode(post_args)
+            )
+        else:
+            response = await http.fetch(url)
+        return escape.json_decode(response.body)
+
+    def get_auth_http_client(self) -> httpclient.AsyncHTTPClient:
+        """Returns the `.AsyncHTTPClient` instance to be used for auth requests.
+
+        May be overridden by subclasses to use an HTTP client other than
+        the default.
+
+        .. versionadded:: 4.3
+        """
+        return httpclient.AsyncHTTPClient()
+
+
+class TwitterMixin(OAuthMixin):
+    """Twitter OAuth authentication.
+
+    To authenticate with Twitter, register your application with
+    Twitter at http://twitter.com/apps. Then copy your Consumer Key
+    and Consumer Secret to the application
+    `~tornado.web.Application.settings` ``twitter_consumer_key`` and
+    ``twitter_consumer_secret``. Use this mixin on the handler for the
+    URL you registered as your application's callback URL.
+
+    When your application is set up, you can use this mixin like this
+    to authenticate the user with Twitter and get access to their stream:
+
+    .. testcode::
+
+        class TwitterLoginHandler(tornado.web.RequestHandler,
+                                  tornado.auth.TwitterMixin):
+            async def get(self):
+                if self.get_argument("oauth_token", None):
+                    user = await self.get_authenticated_user()
+                    # Save the user using e.g. set_signed_cookie()
+                else:
+                    await self.authorize_redirect()
+
+    .. testoutput::
+       :hide:
+
+    The user object returned by `~OAuthMixin.get_authenticated_user`
+    includes the attributes ``username``, ``name``, ``access_token``,
+    and all of the custom Twitter user attributes described at
+    https://dev.twitter.com/docs/api/1.1/get/users/show
+    """
+
+    _OAUTH_REQUEST_TOKEN_URL = "https://api.twitter.com/oauth/request_token"
+    _OAUTH_ACCESS_TOKEN_URL = "https://api.twitter.com/oauth/access_token"
+    _OAUTH_AUTHORIZE_URL = "https://api.twitter.com/oauth/authorize"
+    _OAUTH_AUTHENTICATE_URL = "https://api.twitter.com/oauth/authenticate"
+    _OAUTH_NO_CALLBACKS = False
+    _TWITTER_BASE_URL = "https://api.twitter.com/1.1"
+
+    async def authenticate_redirect(self, callback_uri: Optional[str] = None) -> None:
+        """Just like `~OAuthMixin.authorize_redirect`, but
+        auto-redirects if authorized.
+
+        This is generally the right interface to use if you are using
+        Twitter for single-sign on.
+
+        .. versionchanged:: 3.1
+           Now returns a `.Future` and takes an optional callback, for
+           compatibility with `.gen.coroutine`.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           awaitable object instead.
+        """
+        http = self.get_auth_http_client()
+        response = await http.fetch(
+            self._oauth_request_token_url(callback_uri=callback_uri)
+        )
+        self._on_request_token(self._OAUTH_AUTHENTICATE_URL, None, response)
+
+    async def twitter_request(
+        self,
+        path: str,
+        access_token: Dict[str, Any],
+        post_args: Optional[Dict[str, Any]] = None,
+        **args: Any
+    ) -> Any:
+        """Fetches the given API path, e.g., ``statuses/user_timeline/btaylor``
+
+        The path should not include the format or API version number.
+        (we automatically use JSON format and API version 1).
+
+        If the request is a POST, ``post_args`` should be provided. Query
+        string arguments should be given as keyword arguments.
+
+        All the Twitter methods are documented at http://dev.twitter.com/
+
+        Many methods require an OAuth access token which you can
+        obtain through `~OAuthMixin.authorize_redirect` and
+        `~OAuthMixin.get_authenticated_user`. The user returned through that
+        process includes an 'access_token' attribute that can be used
+        to make authenticated requests via this method. Example
+        usage:
+
+        .. testcode::
+
+            class MainHandler(tornado.web.RequestHandler,
+                              tornado.auth.TwitterMixin):
+                @tornado.web.authenticated
+                async def get(self):
+                    new_entry = await self.twitter_request(
+                        "/statuses/update",
+                        post_args={"status": "Testing Tornado Web Server"},
+                        access_token=self.current_user["access_token"])
+                    if not new_entry:
+                        # Call failed; perhaps missing permission?
+                        await self.authorize_redirect()
+                        return
+                    self.finish("Posted a message!")
+
+        .. testoutput::
+           :hide:
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           awaitable object instead.
+        """
+        if path.startswith("http:") or path.startswith("https:"):
+            # Raw urls are useful for e.g. search which doesn't follow the
+            # usual pattern: http://search.twitter.com/search.json
+            url = path
+        else:
+            url = self._TWITTER_BASE_URL + path + ".json"
+        # Add the OAuth resource request signature if we have credentials
+        if access_token:
+            all_args = {}
+            all_args.update(args)
+            all_args.update(post_args or {})
+            method = "POST" if post_args is not None else "GET"
+            oauth = self._oauth_request_parameters(
+                url, access_token, all_args, method=method
+            )
+            args.update(oauth)
+        if args:
+            url += "?" + urllib.parse.urlencode(args)
+        http = self.get_auth_http_client()
+        if post_args is not None:
+            response = await http.fetch(
+                url, method="POST", body=urllib.parse.urlencode(post_args)
+            )
+        else:
+            response = await http.fetch(url)
+        return escape.json_decode(response.body)
+
+    def _oauth_consumer_token(self) -> Dict[str, Any]:
+        handler = cast(RequestHandler, self)
+        handler.require_setting("twitter_consumer_key", "Twitter OAuth")
+        handler.require_setting("twitter_consumer_secret", "Twitter OAuth")
+        return dict(
+            key=handler.settings["twitter_consumer_key"],
+            secret=handler.settings["twitter_consumer_secret"],
+        )
+
+    async def _oauth_get_user_future(
+        self, access_token: Dict[str, Any]
+    ) -> Dict[str, Any]:
+        user = await self.twitter_request(
+            "/account/verify_credentials", access_token=access_token
+        )
+        if user:
+            user["username"] = user["screen_name"]
+        return user
+
+
+class GoogleOAuth2Mixin(OAuth2Mixin):
+    """Google authentication using OAuth2.
+
+    In order to use, register your application with Google and copy the
+    relevant parameters to your application settings.
+
+    * Go to the Google Dev Console at http://console.developers.google.com
+    * Select a project, or create a new one.
+    * In the sidebar on the left, select Credentials.
+    * Click CREATE CREDENTIALS and click OAuth client ID.
+    * Under Application type, select Web application.
+    * Name OAuth 2.0 client and click Create.
+    * Copy the "Client secret" and "Client ID" to the application settings as
+      ``{"google_oauth": {"key": CLIENT_ID, "secret": CLIENT_SECRET}}``
+
+    .. versionadded:: 3.2
+    """
+
+    _OAUTH_AUTHORIZE_URL = "https://accounts.google.com/o/oauth2/v2/auth"
+    _OAUTH_ACCESS_TOKEN_URL = "https://www.googleapis.com/oauth2/v4/token"
+    _OAUTH_USERINFO_URL = "https://www.googleapis.com/oauth2/v1/userinfo"
+    _OAUTH_NO_CALLBACKS = False
+    _OAUTH_SETTINGS_KEY = "google_oauth"
+
+    def get_google_oauth_settings(self) -> Dict[str, str]:
+        """Return the Google OAuth 2.0 credentials that you created with
+        [Google Cloud
+        Platform](https://console.cloud.google.com/apis/credentials). The dict
+        format is::
+
+            {
+                "key": "your_client_id", "secret": "your_client_secret"
+            }
+
+        If your credentials are stored differently (e.g. in a db) you can
+        override this method for custom provision.
+        """
+        handler = cast(RequestHandler, self)
+        return handler.settings[self._OAUTH_SETTINGS_KEY]
+
+    async def get_authenticated_user(
+        self,
+        redirect_uri: str,
+        code: str,
+        client_id: Optional[str] = None,
+        client_secret: Optional[str] = None,
+    ) -> Dict[str, Any]:
+        """Handles the login for the Google user, returning an access token.
+
+        The result is a dictionary containing an ``access_token`` field
+        ([among others](https://developers.google.com/identity/protocols/OAuth2WebServer#handlingtheresponse)).
+        Unlike other ``get_authenticated_user`` methods in this package,
+        this method does not return any additional information about the user.
+        The returned access token can be used with `OAuth2Mixin.oauth2_request`
+        to request additional information (perhaps from
+        ``https://www.googleapis.com/oauth2/v2/userinfo``)
+
+        Example usage:
+
+        .. testcode::
+
+            class GoogleOAuth2LoginHandler(tornado.web.RequestHandler,
+                                           tornado.auth.GoogleOAuth2Mixin):
+                async def get(self):
+                    if self.get_argument('code', False):
+                        access = await self.get_authenticated_user(
+                            redirect_uri='http://your.site.com/auth/google',
+                            code=self.get_argument('code'))
+                        user = await self.oauth2_request(
+                            "https://www.googleapis.com/oauth2/v1/userinfo",
+                            access_token=access["access_token"])
+                        # Save the user and access token with
+                        # e.g. set_signed_cookie.
+                    else:
+                        self.authorize_redirect(
+                            redirect_uri='http://your.site.com/auth/google',
+                            client_id=self.get_google_oauth_settings()['key'],
+                            scope=['profile', 'email'],
+                            response_type='code',
+                            extra_params={'approval_prompt': 'auto'})
+
+        .. testoutput::
+           :hide:
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned awaitable object instead.
+        """  # noqa: E501
+
+        if client_id is None or client_secret is None:
+            settings = self.get_google_oauth_settings()
+            if client_id is None:
+                client_id = settings["key"]
+            if client_secret is None:
+                client_secret = settings["secret"]
+        http = self.get_auth_http_client()
+        body = urllib.parse.urlencode(
+            {
+                "redirect_uri": redirect_uri,
+                "code": code,
+                "client_id": client_id,
+                "client_secret": client_secret,
+                "grant_type": "authorization_code",
+            }
+        )
+
+        response = await http.fetch(
+            self._OAUTH_ACCESS_TOKEN_URL,
+            method="POST",
+            headers={"Content-Type": "application/x-www-form-urlencoded"},
+            body=body,
+        )
+        return escape.json_decode(response.body)
+
+
+class FacebookGraphMixin(OAuth2Mixin):
+    """Facebook authentication using the new Graph API and OAuth2."""
+
+    _OAUTH_ACCESS_TOKEN_URL = "https://graph.facebook.com/oauth/access_token?"
+    _OAUTH_AUTHORIZE_URL = "https://www.facebook.com/dialog/oauth?"
+    _OAUTH_NO_CALLBACKS = False
+    _FACEBOOK_BASE_URL = "https://graph.facebook.com"
+
+    async def get_authenticated_user(
+        self,
+        redirect_uri: str,
+        client_id: str,
+        client_secret: str,
+        code: str,
+        extra_fields: Optional[Dict[str, Any]] = None,
+    ) -> Optional[Dict[str, Any]]:
+        """Handles the login for the Facebook user, returning a user object.
+
+        Example usage:
+
+        .. testcode::
+
+            class FacebookGraphLoginHandler(tornado.web.RequestHandler,
+                                            tornado.auth.FacebookGraphMixin):
+              async def get(self):
+                  if self.get_argument("code", False):
+                      user = await self.get_authenticated_user(
+                          redirect_uri='/auth/facebookgraph/',
+                          client_id=self.settings["facebook_api_key"],
+                          client_secret=self.settings["facebook_secret"],
+                          code=self.get_argument("code"))
+                      # Save the user with e.g. set_signed_cookie
+                  else:
+                      self.authorize_redirect(
+                          redirect_uri='/auth/facebookgraph/',
+                          client_id=self.settings["facebook_api_key"],
+                          extra_params={"scope": "read_stream,offline_access"})
+
+        .. testoutput::
+           :hide:
+
+        This method returns a dictionary which may contain the following fields:
+
+        * ``access_token``, a string which may be passed to `facebook_request`
+        * ``session_expires``, an integer encoded as a string representing
+          the time until the access token expires in seconds. This field should
+          be used like ``int(user['session_expires'])``; in a future version of
+          Tornado it will change from a string to an integer.
+        * ``id``, ``name``, ``first_name``, ``last_name``, ``locale``, ``picture``,
+          ``link``, plus any fields named in the ``extra_fields`` argument. These
+          fields are copied from the Facebook graph API
+          `user object <https://developers.facebook.com/docs/graph-api/reference/user>`_
+
+        .. versionchanged:: 4.5
+           The ``session_expires`` field was updated to support changes made to the
+           Facebook API in March 2017.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned awaitable object instead.
+        """
+        http = self.get_auth_http_client()
+        args = {
+            "redirect_uri": redirect_uri,
+            "code": code,
+            "client_id": client_id,
+            "client_secret": client_secret,
+        }
+
+        fields = set(
+            ["id", "name", "first_name", "last_name", "locale", "picture", "link"]
+        )
+        if extra_fields:
+            fields.update(extra_fields)
+
+        response = await http.fetch(
+            self._oauth_request_token_url(**args)  # type: ignore
+        )
+        args = escape.json_decode(response.body)
+        session = {
+            "access_token": args.get("access_token"),
+            "expires_in": args.get("expires_in"),
+        }
+        assert session["access_token"] is not None
+
+        user = await self.facebook_request(
+            path="/me",
+            access_token=session["access_token"],
+            appsecret_proof=hmac.new(
+                key=client_secret.encode("utf8"),
+                msg=session["access_token"].encode("utf8"),
+                digestmod=hashlib.sha256,
+            ).hexdigest(),
+            fields=",".join(fields),
+        )
+
+        if user is None:
+            return None
+
+        fieldmap = {}
+        for field in fields:
+            fieldmap[field] = user.get(field)
+
+        # session_expires is converted to str for compatibility with
+        # older versions in which the server used url-encoding and
+        # this code simply returned the string verbatim.
+        # This should change in Tornado 5.0.
+        fieldmap.update(
+            {
+                "access_token": session["access_token"],
+                "session_expires": str(session.get("expires_in")),
+            }
+        )
+        return fieldmap
+
+    async def facebook_request(
+        self,
+        path: str,
+        access_token: Optional[str] = None,
+        post_args: Optional[Dict[str, Any]] = None,
+        **args: Any
+    ) -> Any:
+        """Fetches the given relative API path, e.g., "/btaylor/picture"
+
+        If the request is a POST, ``post_args`` should be provided. Query
+        string arguments should be given as keyword arguments.
+
+        An introduction to the Facebook Graph API can be found at
+        http://developers.facebook.com/docs/api
+
+        Many methods require an OAuth access token which you can
+        obtain through `~OAuth2Mixin.authorize_redirect` and
+        `get_authenticated_user`. The user returned through that
+        process includes an ``access_token`` attribute that can be
+        used to make authenticated requests via this method.
+
+        Example usage:
+
+        .. testcode::
+
+            class MainHandler(tornado.web.RequestHandler,
+                              tornado.auth.FacebookGraphMixin):
+                @tornado.web.authenticated
+                async def get(self):
+                    new_entry = await self.facebook_request(
+                        "/me/feed",
+                        post_args={"message": "I am posting from my Tornado application!"},
+                        access_token=self.current_user["access_token"])
+
+                    if not new_entry:
+                        # Call failed; perhaps missing permission?
+                        self.authorize_redirect()
+                        return
+                    self.finish("Posted a message!")
+
+        .. testoutput::
+           :hide:
+
+        The given path is relative to ``self._FACEBOOK_BASE_URL``,
+        by default "https://graph.facebook.com".
+
+        This method is a wrapper around `OAuth2Mixin.oauth2_request`;
+        the only difference is that this method takes a relative path,
+        while ``oauth2_request`` takes a complete url.
+
+        .. versionchanged:: 3.1
+           Added the ability to override ``self._FACEBOOK_BASE_URL``.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned awaitable object instead.
+        """
+        url = self._FACEBOOK_BASE_URL + path
+        return await self.oauth2_request(
+            url, access_token=access_token, post_args=post_args, **args
+        )
+
+
+def _oauth_signature(
+    consumer_token: Dict[str, Any],
+    method: str,
+    url: str,
+    parameters: Dict[str, Any] = {},
+    token: Optional[Dict[str, Any]] = None,
+) -> bytes:
+    """Calculates the HMAC-SHA1 OAuth signature for the given request.
+
+    See http://oauth.net/core/1.0/#signing_process
+    """
+    parts = urllib.parse.urlparse(url)
+    scheme, netloc, path = parts[:3]
+    normalized_url = scheme.lower() + "://" + netloc.lower() + path
+
+    base_elems = []
+    base_elems.append(method.upper())
+    base_elems.append(normalized_url)
+    base_elems.append(
+        "&".join(
+            "%s=%s" % (k, _oauth_escape(str(v))) for k, v in sorted(parameters.items())
+        )
+    )
+    base_string = "&".join(_oauth_escape(e) for e in base_elems)
+
+    key_elems = [escape.utf8(consumer_token["secret"])]
+    key_elems.append(escape.utf8(token["secret"] if token else ""))
+    key = b"&".join(key_elems)
+
+    hash = hmac.new(key, escape.utf8(base_string), hashlib.sha1)
+    return binascii.b2a_base64(hash.digest())[:-1]
+
+
+def _oauth10a_signature(
+    consumer_token: Dict[str, Any],
+    method: str,
+    url: str,
+    parameters: Dict[str, Any] = {},
+    token: Optional[Dict[str, Any]] = None,
+) -> bytes:
+    """Calculates the HMAC-SHA1 OAuth 1.0a signature for the given request.
+
+    See http://oauth.net/core/1.0a/#signing_process
+    """
+    parts = urllib.parse.urlparse(url)
+    scheme, netloc, path = parts[:3]
+    normalized_url = scheme.lower() + "://" + netloc.lower() + path
+
+    base_elems = []
+    base_elems.append(method.upper())
+    base_elems.append(normalized_url)
+    base_elems.append(
+        "&".join(
+            "%s=%s" % (k, _oauth_escape(str(v))) for k, v in sorted(parameters.items())
+        )
+    )
+
+    base_string = "&".join(_oauth_escape(e) for e in base_elems)
+    key_elems = [escape.utf8(urllib.parse.quote(consumer_token["secret"], safe="~"))]
+    key_elems.append(
+        escape.utf8(urllib.parse.quote(token["secret"], safe="~") if token else "")
+    )
+    key = b"&".join(key_elems)
+
+    hash = hmac.new(key, escape.utf8(base_string), hashlib.sha1)
+    return binascii.b2a_base64(hash.digest())[:-1]
+
+
+def _oauth_escape(val: Union[str, bytes]) -> str:
+    if isinstance(val, unicode_type):
+        val = val.encode("utf-8")
+    return urllib.parse.quote(val, safe="~")
+
+
+def _oauth_parse_response(body: bytes) -> Dict[str, Any]:
+    # I can't find an officially-defined encoding for oauth responses and
+    # have never seen anyone use non-ascii.  Leave the response in a byte
+    # string for python 2, and use utf8 on python 3.
+    body_str = escape.native_str(body)
+    p = urllib.parse.parse_qs(body_str, keep_blank_values=False)
+    token = dict(key=p["oauth_token"][0], secret=p["oauth_token_secret"][0])
+
+    # Add the extra parameters the Provider included to the token
+    special = ("oauth_token", "oauth_token_secret")
+    token.update((k, p[k][0]) for k in p if k not in special)
+    return token
diff --git a/venv/lib/python3.9/site-packages/tornado/autoreload.py b/venv/lib/python3.9/site-packages/tornado/autoreload.py
new file mode 100644
index 00000000..0ac44966
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/autoreload.py
@@ -0,0 +1,360 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Automatically restart the server when a source file is modified.
+
+Most applications should not access this module directly.  Instead,
+pass the keyword argument ``autoreload=True`` to the
+`tornado.web.Application` constructor (or ``debug=True``, which
+enables this setting and several others).  This will enable autoreload
+mode as well as checking for changes to templates and static
+resources.  Note that restarting is a destructive operation and any
+requests in progress will be aborted when the process restarts.  (If
+you want to disable autoreload while using other debug-mode features,
+pass both ``debug=True`` and ``autoreload=False``).
+
+This module can also be used as a command-line wrapper around scripts
+such as unit test runners.  See the `main` method for details.
+
+The command-line wrapper and Application debug modes can be used together.
+This combination is encouraged as the wrapper catches syntax errors and
+other import-time failures, while debug mode catches changes once
+the server has started.
+
+This module will not work correctly when `.HTTPServer`'s multi-process
+mode is used.
+
+Reloading loses any Python interpreter command-line arguments (e.g. ``-u``)
+because it re-executes Python using ``sys.executable`` and ``sys.argv``.
+Additionally, modifying these variables will cause reloading to behave
+incorrectly.
+
+"""
+
+import os
+import sys
+
+# sys.path handling
+# -----------------
+#
+# If a module is run with "python -m", the current directory (i.e. "")
+# is automatically prepended to sys.path, but not if it is run as
+# "path/to/file.py".  The processing for "-m" rewrites the former to
+# the latter, so subsequent executions won't have the same path as the
+# original.
+#
+# Conversely, when run as path/to/file.py, the directory containing
+# file.py gets added to the path, which can cause confusion as imports
+# may become relative in spite of the future import.
+#
+# We address the former problem by reconstructing the original command
+# line (Python >= 3.4) or by setting the $PYTHONPATH environment
+# variable (Python < 3.4) before re-execution so the new process will
+# see the correct path.  We attempt to address the latter problem when
+# tornado.autoreload is run as __main__.
+
+if __name__ == "__main__":
+    # This sys.path manipulation must come before our imports (as much
+    # as possible - if we introduced a tornado.sys or tornado.os
+    # module we'd be in trouble), or else our imports would become
+    # relative again despite the future import.
+    #
+    # There is a separate __main__ block at the end of the file to call main().
+    if sys.path[0] == os.path.dirname(__file__):
+        del sys.path[0]
+
+import functools
+import os
+import pkgutil  # type: ignore
+import sys
+import traceback
+import types
+import subprocess
+import weakref
+
+from tornado import ioloop
+from tornado.log import gen_log
+from tornado import process
+from tornado.util import exec_in
+
+try:
+    import signal
+except ImportError:
+    signal = None  # type: ignore
+
+import typing
+from typing import Callable, Dict
+
+if typing.TYPE_CHECKING:
+    from typing import List, Optional, Union  # noqa: F401
+
+# os.execv is broken on Windows and can't properly parse command line
+# arguments and executable name if they contain whitespaces. subprocess
+# fixes that behavior.
+_has_execv = sys.platform != "win32"
+
+_watched_files = set()
+_reload_hooks = []
+_reload_attempted = False
+_io_loops = weakref.WeakKeyDictionary()  # type: ignore
+_autoreload_is_main = False
+_original_argv = None  # type: Optional[List[str]]
+_original_spec = None
+
+
+def start(check_time: int = 500) -> None:
+    """Begins watching source files for changes.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+    """
+    io_loop = ioloop.IOLoop.current()
+    if io_loop in _io_loops:
+        return
+    _io_loops[io_loop] = True
+    if len(_io_loops) > 1:
+        gen_log.warning("tornado.autoreload started more than once in the same process")
+    modify_times = {}  # type: Dict[str, float]
+    callback = functools.partial(_reload_on_update, modify_times)
+    scheduler = ioloop.PeriodicCallback(callback, check_time)
+    scheduler.start()
+
+
+def wait() -> None:
+    """Wait for a watched file to change, then restart the process.
+
+    Intended to be used at the end of scripts like unit test runners,
+    to run the tests again after any source file changes (but see also
+    the command-line interface in `main`)
+    """
+    io_loop = ioloop.IOLoop()
+    io_loop.add_callback(start)
+    io_loop.start()
+
+
+def watch(filename: str) -> None:
+    """Add a file to the watch list.
+
+    All imported modules are watched by default.
+    """
+    _watched_files.add(filename)
+
+
+def add_reload_hook(fn: Callable[[], None]) -> None:
+    """Add a function to be called before reloading the process.
+
+    Note that for open file and socket handles it is generally
+    preferable to set the ``FD_CLOEXEC`` flag (using `fcntl` or
+    `os.set_inheritable`) instead of using a reload hook to close them.
+    """
+    _reload_hooks.append(fn)
+
+
+def _reload_on_update(modify_times: Dict[str, float]) -> None:
+    if _reload_attempted:
+        # We already tried to reload and it didn't work, so don't try again.
+        return
+    if process.task_id() is not None:
+        # We're in a child process created by fork_processes.  If child
+        # processes restarted themselves, they'd all restart and then
+        # all call fork_processes again.
+        return
+    for module in list(sys.modules.values()):
+        # Some modules play games with sys.modules (e.g. email/__init__.py
+        # in the standard library), and occasionally this can cause strange
+        # failures in getattr.  Just ignore anything that's not an ordinary
+        # module.
+        if not isinstance(module, types.ModuleType):
+            continue
+        path = getattr(module, "__file__", None)
+        if not path:
+            continue
+        if path.endswith(".pyc") or path.endswith(".pyo"):
+            path = path[:-1]
+        _check_file(modify_times, path)
+    for path in _watched_files:
+        _check_file(modify_times, path)
+
+
+def _check_file(modify_times: Dict[str, float], path: str) -> None:
+    try:
+        modified = os.stat(path).st_mtime
+    except Exception:
+        return
+    if path not in modify_times:
+        modify_times[path] = modified
+        return
+    if modify_times[path] != modified:
+        gen_log.info("%s modified; restarting server", path)
+        _reload()
+
+
+def _reload() -> None:
+    global _reload_attempted
+    _reload_attempted = True
+    for fn in _reload_hooks:
+        fn()
+    if sys.platform != "win32":
+        # Clear the alarm signal set by
+        # ioloop.set_blocking_log_threshold so it doesn't fire
+        # after the exec.
+        signal.setitimer(signal.ITIMER_REAL, 0, 0)
+    # sys.path fixes: see comments at top of file.  If __main__.__spec__
+    # exists, we were invoked with -m and the effective path is about to
+    # change on re-exec.  Reconstruct the original command line to
+    # ensure that the new process sees the same path we did.  If
+    # __spec__ is not available (Python < 3.4), check instead if
+    # sys.path[0] is an empty string and add the current directory to
+    # $PYTHONPATH.
+    if _autoreload_is_main:
+        assert _original_argv is not None
+        spec = _original_spec
+        argv = _original_argv
+    else:
+        spec = getattr(sys.modules["__main__"], "__spec__", None)
+        argv = sys.argv
+    if spec:
+        argv = ["-m", spec.name] + argv[1:]
+    else:
+        path_prefix = "." + os.pathsep
+        if sys.path[0] == "" and not os.environ.get("PYTHONPATH", "").startswith(
+            path_prefix
+        ):
+            os.environ["PYTHONPATH"] = path_prefix + os.environ.get("PYTHONPATH", "")
+    if not _has_execv:
+        subprocess.Popen([sys.executable] + argv)
+        os._exit(0)
+    else:
+        try:
+            os.execv(sys.executable, [sys.executable] + argv)
+        except OSError:
+            # Mac OS X versions prior to 10.6 do not support execv in
+            # a process that contains multiple threads.  Instead of
+            # re-executing in the current process, start a new one
+            # and cause the current process to exit.  This isn't
+            # ideal since the new process is detached from the parent
+            # terminal and thus cannot easily be killed with ctrl-C,
+            # but it's better than not being able to autoreload at
+            # all.
+            # Unfortunately the errno returned in this case does not
+            # appear to be consistent, so we can't easily check for
+            # this error specifically.
+            os.spawnv(
+                os.P_NOWAIT, sys.executable, [sys.executable] + argv  # type: ignore
+            )
+            # At this point the IOLoop has been closed and finally
+            # blocks will experience errors if we allow the stack to
+            # unwind, so just exit uncleanly.
+            os._exit(0)
+
+
+_USAGE = """\
+Usage:
+  python -m tornado.autoreload -m module.to.run [args...]
+  python -m tornado.autoreload path/to/script.py [args...]
+"""
+
+
+def main() -> None:
+    """Command-line wrapper to re-run a script whenever its source changes.
+
+    Scripts may be specified by filename or module name::
+
+        python -m tornado.autoreload -m tornado.test.runtests
+        python -m tornado.autoreload tornado/test/runtests.py
+
+    Running a script with this wrapper is similar to calling
+    `tornado.autoreload.wait` at the end of the script, but this wrapper
+    can catch import-time problems like syntax errors that would otherwise
+    prevent the script from reaching its call to `wait`.
+    """
+    # Remember that we were launched with autoreload as main.
+    # The main module can be tricky; set the variables both in our globals
+    # (which may be __main__) and the real importable version.
+    import tornado.autoreload
+
+    global _autoreload_is_main
+    global _original_argv, _original_spec
+    tornado.autoreload._autoreload_is_main = _autoreload_is_main = True
+    original_argv = sys.argv
+    tornado.autoreload._original_argv = _original_argv = original_argv
+    original_spec = getattr(sys.modules["__main__"], "__spec__", None)
+    tornado.autoreload._original_spec = _original_spec = original_spec
+    sys.argv = sys.argv[:]
+    if len(sys.argv) >= 3 and sys.argv[1] == "-m":
+        mode = "module"
+        module = sys.argv[2]
+        del sys.argv[1:3]
+    elif len(sys.argv) >= 2:
+        mode = "script"
+        script = sys.argv[1]
+        sys.argv = sys.argv[1:]
+    else:
+        print(_USAGE, file=sys.stderr)
+        sys.exit(1)
+
+    try:
+        if mode == "module":
+            import runpy
+
+            runpy.run_module(module, run_name="__main__", alter_sys=True)
+        elif mode == "script":
+            with open(script) as f:
+                # Execute the script in our namespace instead of creating
+                # a new one so that something that tries to import __main__
+                # (e.g. the unittest module) will see names defined in the
+                # script instead of just those defined in this module.
+                global __file__
+                __file__ = script
+                # If __package__ is defined, imports may be incorrectly
+                # interpreted as relative to this module.
+                global __package__
+                del __package__
+                exec_in(f.read(), globals(), globals())
+    except SystemExit as e:
+        gen_log.info("Script exited with status %s", e.code)
+    except Exception as e:
+        gen_log.warning("Script exited with uncaught exception", exc_info=True)
+        # If an exception occurred at import time, the file with the error
+        # never made it into sys.modules and so we won't know to watch it.
+        # Just to make sure we've covered everything, walk the stack trace
+        # from the exception and watch every file.
+        for (filename, lineno, name, line) in traceback.extract_tb(sys.exc_info()[2]):
+            watch(filename)
+        if isinstance(e, SyntaxError):
+            # SyntaxErrors are special:  their innermost stack frame is fake
+            # so extract_tb won't see it and we have to get the filename
+            # from the exception object.
+            if e.filename is not None:
+                watch(e.filename)
+    else:
+        gen_log.info("Script exited normally")
+    # restore sys.argv so subsequent executions will include autoreload
+    sys.argv = original_argv
+
+    if mode == "module":
+        # runpy did a fake import of the module as __main__, but now it's
+        # no longer in sys.modules.  Figure out where it is and watch it.
+        loader = pkgutil.get_loader(module)
+        if loader is not None:
+            watch(loader.get_filename())  # type: ignore
+
+    wait()
+
+
+if __name__ == "__main__":
+    # See also the other __main__ block at the top of the file, which modifies
+    # sys.path before our imports
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/concurrent.py b/venv/lib/python3.9/site-packages/tornado/concurrent.py
new file mode 100644
index 00000000..6e05346b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/concurrent.py
@@ -0,0 +1,265 @@
+#
+# Copyright 2012 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+"""Utilities for working with ``Future`` objects.
+
+Tornado previously provided its own ``Future`` class, but now uses
+`asyncio.Future`. This module contains utility functions for working
+with `asyncio.Future` in a way that is backwards-compatible with
+Tornado's old ``Future`` implementation.
+
+While this module is an important part of Tornado's internal
+implementation, applications rarely need to interact with it
+directly.
+
+"""
+
+import asyncio
+from concurrent import futures
+import functools
+import sys
+import types
+
+from tornado.log import app_log
+
+import typing
+from typing import Any, Callable, Optional, Tuple, Union
+
+_T = typing.TypeVar("_T")
+
+
+class ReturnValueIgnoredError(Exception):
+    # No longer used; was previously used by @return_future
+    pass
+
+
+Future = asyncio.Future
+
+FUTURES = (futures.Future, Future)
+
+
+def is_future(x: Any) -> bool:
+    return isinstance(x, FUTURES)
+
+
+class DummyExecutor(futures.Executor):
+    def submit(
+        self, fn: Callable[..., _T], *args: Any, **kwargs: Any
+    ) -> "futures.Future[_T]":
+        future = futures.Future()  # type: futures.Future[_T]
+        try:
+            future_set_result_unless_cancelled(future, fn(*args, **kwargs))
+        except Exception:
+            future_set_exc_info(future, sys.exc_info())
+        return future
+
+    def shutdown(self, wait: bool = True) -> None:
+        pass
+
+
+dummy_executor = DummyExecutor()
+
+
+def run_on_executor(*args: Any, **kwargs: Any) -> Callable:
+    """Decorator to run a synchronous method asynchronously on an executor.
+
+    Returns a future.
+
+    The executor to be used is determined by the ``executor``
+    attributes of ``self``. To use a different attribute name, pass a
+    keyword argument to the decorator::
+
+        @run_on_executor(executor='_thread_pool')
+        def foo(self):
+            pass
+
+    This decorator should not be confused with the similarly-named
+    `.IOLoop.run_in_executor`. In general, using ``run_in_executor``
+    when *calling* a blocking method is recommended instead of using
+    this decorator when *defining* a method. If compatibility with older
+    versions of Tornado is required, consider defining an executor
+    and using ``executor.submit()`` at the call site.
+
+    .. versionchanged:: 4.2
+       Added keyword arguments to use alternative attributes.
+
+    .. versionchanged:: 5.0
+       Always uses the current IOLoop instead of ``self.io_loop``.
+
+    .. versionchanged:: 5.1
+       Returns a `.Future` compatible with ``await`` instead of a
+       `concurrent.futures.Future`.
+
+    .. deprecated:: 5.1
+
+       The ``callback`` argument is deprecated and will be removed in
+       6.0. The decorator itself is discouraged in new code but will
+       not be removed in 6.0.
+
+    .. versionchanged:: 6.0
+
+       The ``callback`` argument was removed.
+    """
+    # Fully type-checking decorators is tricky, and this one is
+    # discouraged anyway so it doesn't have all the generic magic.
+    def run_on_executor_decorator(fn: Callable) -> Callable[..., Future]:
+        executor = kwargs.get("executor", "executor")
+
+        @functools.wraps(fn)
+        def wrapper(self: Any, *args: Any, **kwargs: Any) -> Future:
+            async_future = Future()  # type: Future
+            conc_future = getattr(self, executor).submit(fn, self, *args, **kwargs)
+            chain_future(conc_future, async_future)
+            return async_future
+
+        return wrapper
+
+    if args and kwargs:
+        raise ValueError("cannot combine positional and keyword args")
+    if len(args) == 1:
+        return run_on_executor_decorator(args[0])
+    elif len(args) != 0:
+        raise ValueError("expected 1 argument, got %d", len(args))
+    return run_on_executor_decorator
+
+
+_NO_RESULT = object()
+
+
+def chain_future(a: "Future[_T]", b: "Future[_T]") -> None:
+    """Chain two futures together so that when one completes, so does the other.
+
+    The result (success or failure) of ``a`` will be copied to ``b``, unless
+    ``b`` has already been completed or cancelled by the time ``a`` finishes.
+
+    .. versionchanged:: 5.0
+
+       Now accepts both Tornado/asyncio `Future` objects and
+       `concurrent.futures.Future`.
+
+    """
+
+    def copy(future: "Future[_T]") -> None:
+        assert future is a
+        if b.done():
+            return
+        if hasattr(a, "exc_info") and a.exc_info() is not None:  # type: ignore
+            future_set_exc_info(b, a.exc_info())  # type: ignore
+        else:
+            a_exc = a.exception()
+            if a_exc is not None:
+                b.set_exception(a_exc)
+            else:
+                b.set_result(a.result())
+
+    if isinstance(a, Future):
+        future_add_done_callback(a, copy)
+    else:
+        # concurrent.futures.Future
+        from tornado.ioloop import IOLoop
+
+        IOLoop.current().add_future(a, copy)
+
+
+def future_set_result_unless_cancelled(
+    future: "Union[futures.Future[_T], Future[_T]]", value: _T
+) -> None:
+    """Set the given ``value`` as the `Future`'s result, if not cancelled.
+
+    Avoids ``asyncio.InvalidStateError`` when calling ``set_result()`` on
+    a cancelled `asyncio.Future`.
+
+    .. versionadded:: 5.0
+    """
+    if not future.cancelled():
+        future.set_result(value)
+
+
+def future_set_exception_unless_cancelled(
+    future: "Union[futures.Future[_T], Future[_T]]", exc: BaseException
+) -> None:
+    """Set the given ``exc`` as the `Future`'s exception.
+
+    If the Future is already canceled, logs the exception instead. If
+    this logging is not desired, the caller should explicitly check
+    the state of the Future and call ``Future.set_exception`` instead of
+    this wrapper.
+
+    Avoids ``asyncio.InvalidStateError`` when calling ``set_exception()`` on
+    a cancelled `asyncio.Future`.
+
+    .. versionadded:: 6.0
+
+    """
+    if not future.cancelled():
+        future.set_exception(exc)
+    else:
+        app_log.error("Exception after Future was cancelled", exc_info=exc)
+
+
+def future_set_exc_info(
+    future: "Union[futures.Future[_T], Future[_T]]",
+    exc_info: Tuple[
+        Optional[type], Optional[BaseException], Optional[types.TracebackType]
+    ],
+) -> None:
+    """Set the given ``exc_info`` as the `Future`'s exception.
+
+    Understands both `asyncio.Future` and the extensions in older
+    versions of Tornado to enable better tracebacks on Python 2.
+
+    .. versionadded:: 5.0
+
+    .. versionchanged:: 6.0
+
+       If the future is already cancelled, this function is a no-op.
+       (previously ``asyncio.InvalidStateError`` would be raised)
+
+    """
+    if exc_info[1] is None:
+        raise Exception("future_set_exc_info called with no exception")
+    future_set_exception_unless_cancelled(future, exc_info[1])
+
+
+@typing.overload
+def future_add_done_callback(
+    future: "futures.Future[_T]", callback: Callable[["futures.Future[_T]"], None]
+) -> None:
+    pass
+
+
+@typing.overload  # noqa: F811
+def future_add_done_callback(
+    future: "Future[_T]", callback: Callable[["Future[_T]"], None]
+) -> None:
+    pass
+
+
+def future_add_done_callback(  # noqa: F811
+    future: "Union[futures.Future[_T], Future[_T]]", callback: Callable[..., None]
+) -> None:
+    """Arrange to call ``callback`` when ``future`` is complete.
+
+    ``callback`` is invoked with one argument, the ``future``.
+
+    If ``future`` is already done, ``callback`` is invoked immediately.
+    This may differ from the behavior of ``Future.add_done_callback``,
+    which makes no such guarantee.
+
+    .. versionadded:: 5.0
+    """
+    if future.done():
+        callback(future)
+    else:
+        future.add_done_callback(callback)
diff --git a/venv/lib/python3.9/site-packages/tornado/curl_httpclient.py b/venv/lib/python3.9/site-packages/tornado/curl_httpclient.py
new file mode 100644
index 00000000..23320e48
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/curl_httpclient.py
@@ -0,0 +1,584 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Non-blocking HTTP client implementation using pycurl."""
+
+import collections
+import functools
+import logging
+import pycurl
+import threading
+import time
+from io import BytesIO
+
+from tornado import httputil
+from tornado import ioloop
+
+from tornado.escape import utf8, native_str
+from tornado.httpclient import (
+    HTTPRequest,
+    HTTPResponse,
+    HTTPError,
+    AsyncHTTPClient,
+    main,
+)
+from tornado.log import app_log
+
+from typing import Dict, Any, Callable, Union, Optional
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Deque, Tuple  # noqa: F401
+
+curl_log = logging.getLogger("tornado.curl_httpclient")
+
+
+class CurlAsyncHTTPClient(AsyncHTTPClient):
+    def initialize(  # type: ignore
+        self, max_clients: int = 10, defaults: Optional[Dict[str, Any]] = None
+    ) -> None:
+        super().initialize(defaults=defaults)
+        # Typeshed is incomplete for CurlMulti, so just use Any for now.
+        self._multi = pycurl.CurlMulti()  # type: Any
+        self._multi.setopt(pycurl.M_TIMERFUNCTION, self._set_timeout)
+        self._multi.setopt(pycurl.M_SOCKETFUNCTION, self._handle_socket)
+        self._curls = [self._curl_create() for i in range(max_clients)]
+        self._free_list = self._curls[:]
+        self._requests = (
+            collections.deque()
+        )  # type: Deque[Tuple[HTTPRequest, Callable[[HTTPResponse], None], float]]
+        self._fds = {}  # type: Dict[int, int]
+        self._timeout = None  # type: Optional[object]
+
+        # libcurl has bugs that sometimes cause it to not report all
+        # relevant file descriptors and timeouts to TIMERFUNCTION/
+        # SOCKETFUNCTION.  Mitigate the effects of such bugs by
+        # forcing a periodic scan of all active requests.
+        self._force_timeout_callback = ioloop.PeriodicCallback(
+            self._handle_force_timeout, 1000
+        )
+        self._force_timeout_callback.start()
+
+        # Work around a bug in libcurl 7.29.0: Some fields in the curl
+        # multi object are initialized lazily, and its destructor will
+        # segfault if it is destroyed without having been used.  Add
+        # and remove a dummy handle to make sure everything is
+        # initialized.
+        dummy_curl_handle = pycurl.Curl()
+        self._multi.add_handle(dummy_curl_handle)
+        self._multi.remove_handle(dummy_curl_handle)
+
+    def close(self) -> None:
+        self._force_timeout_callback.stop()
+        if self._timeout is not None:
+            self.io_loop.remove_timeout(self._timeout)
+        for curl in self._curls:
+            curl.close()
+        self._multi.close()
+        super().close()
+
+        # Set below properties to None to reduce the reference count of current
+        # instance, because those properties hold some methods of current
+        # instance that will case circular reference.
+        self._force_timeout_callback = None  # type: ignore
+        self._multi = None
+
+    def fetch_impl(
+        self, request: HTTPRequest, callback: Callable[[HTTPResponse], None]
+    ) -> None:
+        self._requests.append((request, callback, self.io_loop.time()))
+        self._process_queue()
+        self._set_timeout(0)
+
+    def _handle_socket(self, event: int, fd: int, multi: Any, data: bytes) -> None:
+        """Called by libcurl when it wants to change the file descriptors
+        it cares about.
+        """
+        event_map = {
+            pycurl.POLL_NONE: ioloop.IOLoop.NONE,
+            pycurl.POLL_IN: ioloop.IOLoop.READ,
+            pycurl.POLL_OUT: ioloop.IOLoop.WRITE,
+            pycurl.POLL_INOUT: ioloop.IOLoop.READ | ioloop.IOLoop.WRITE,
+        }
+        if event == pycurl.POLL_REMOVE:
+            if fd in self._fds:
+                self.io_loop.remove_handler(fd)
+                del self._fds[fd]
+        else:
+            ioloop_event = event_map[event]
+            # libcurl sometimes closes a socket and then opens a new
+            # one using the same FD without giving us a POLL_NONE in
+            # between.  This is a problem with the epoll IOLoop,
+            # because the kernel can tell when a socket is closed and
+            # removes it from the epoll automatically, causing future
+            # update_handler calls to fail.  Since we can't tell when
+            # this has happened, always use remove and re-add
+            # instead of update.
+            if fd in self._fds:
+                self.io_loop.remove_handler(fd)
+            self.io_loop.add_handler(fd, self._handle_events, ioloop_event)
+            self._fds[fd] = ioloop_event
+
+    def _set_timeout(self, msecs: int) -> None:
+        """Called by libcurl to schedule a timeout."""
+        if self._timeout is not None:
+            self.io_loop.remove_timeout(self._timeout)
+        self._timeout = self.io_loop.add_timeout(
+            self.io_loop.time() + msecs / 1000.0, self._handle_timeout
+        )
+
+    def _handle_events(self, fd: int, events: int) -> None:
+        """Called by IOLoop when there is activity on one of our
+        file descriptors.
+        """
+        action = 0
+        if events & ioloop.IOLoop.READ:
+            action |= pycurl.CSELECT_IN
+        if events & ioloop.IOLoop.WRITE:
+            action |= pycurl.CSELECT_OUT
+        while True:
+            try:
+                ret, num_handles = self._multi.socket_action(fd, action)
+            except pycurl.error as e:
+                ret = e.args[0]
+            if ret != pycurl.E_CALL_MULTI_PERFORM:
+                break
+        self._finish_pending_requests()
+
+    def _handle_timeout(self) -> None:
+        """Called by IOLoop when the requested timeout has passed."""
+        self._timeout = None
+        while True:
+            try:
+                ret, num_handles = self._multi.socket_action(pycurl.SOCKET_TIMEOUT, 0)
+            except pycurl.error as e:
+                ret = e.args[0]
+            if ret != pycurl.E_CALL_MULTI_PERFORM:
+                break
+        self._finish_pending_requests()
+
+        # In theory, we shouldn't have to do this because curl will
+        # call _set_timeout whenever the timeout changes.  However,
+        # sometimes after _handle_timeout we will need to reschedule
+        # immediately even though nothing has changed from curl's
+        # perspective.  This is because when socket_action is
+        # called with SOCKET_TIMEOUT, libcurl decides internally which
+        # timeouts need to be processed by using a monotonic clock
+        # (where available) while tornado uses python's time.time()
+        # to decide when timeouts have occurred.  When those clocks
+        # disagree on elapsed time (as they will whenever there is an
+        # NTP adjustment), tornado might call _handle_timeout before
+        # libcurl is ready.  After each timeout, resync the scheduled
+        # timeout with libcurl's current state.
+        new_timeout = self._multi.timeout()
+        if new_timeout >= 0:
+            self._set_timeout(new_timeout)
+
+    def _handle_force_timeout(self) -> None:
+        """Called by IOLoop periodically to ask libcurl to process any
+        events it may have forgotten about.
+        """
+        while True:
+            try:
+                ret, num_handles = self._multi.socket_all()
+            except pycurl.error as e:
+                ret = e.args[0]
+            if ret != pycurl.E_CALL_MULTI_PERFORM:
+                break
+        self._finish_pending_requests()
+
+    def _finish_pending_requests(self) -> None:
+        """Process any requests that were completed by the last
+        call to multi.socket_action.
+        """
+        while True:
+            num_q, ok_list, err_list = self._multi.info_read()
+            for curl in ok_list:
+                self._finish(curl)
+            for curl, errnum, errmsg in err_list:
+                self._finish(curl, errnum, errmsg)
+            if num_q == 0:
+                break
+        self._process_queue()
+
+    def _process_queue(self) -> None:
+        while True:
+            started = 0
+            while self._free_list and self._requests:
+                started += 1
+                curl = self._free_list.pop()
+                (request, callback, queue_start_time) = self._requests.popleft()
+                # TODO: Don't smuggle extra data on an attribute of the Curl object.
+                curl.info = {  # type: ignore
+                    "headers": httputil.HTTPHeaders(),
+                    "buffer": BytesIO(),
+                    "request": request,
+                    "callback": callback,
+                    "queue_start_time": queue_start_time,
+                    "curl_start_time": time.time(),
+                    "curl_start_ioloop_time": self.io_loop.current().time(),  # type: ignore
+                }
+                try:
+                    self._curl_setup_request(
+                        curl,
+                        request,
+                        curl.info["buffer"],  # type: ignore
+                        curl.info["headers"],  # type: ignore
+                    )
+                except Exception as e:
+                    # If there was an error in setup, pass it on
+                    # to the callback. Note that allowing the
+                    # error to escape here will appear to work
+                    # most of the time since we are still in the
+                    # caller's original stack frame, but when
+                    # _process_queue() is called from
+                    # _finish_pending_requests the exceptions have
+                    # nowhere to go.
+                    self._free_list.append(curl)
+                    callback(HTTPResponse(request=request, code=599, error=e))
+                else:
+                    self._multi.add_handle(curl)
+
+            if not started:
+                break
+
+    def _finish(
+        self,
+        curl: pycurl.Curl,
+        curl_error: Optional[int] = None,
+        curl_message: Optional[str] = None,
+    ) -> None:
+        info = curl.info  # type: ignore
+        curl.info = None  # type: ignore
+        self._multi.remove_handle(curl)
+        self._free_list.append(curl)
+        buffer = info["buffer"]
+        if curl_error:
+            assert curl_message is not None
+            error = CurlError(curl_error, curl_message)  # type: Optional[CurlError]
+            assert error is not None
+            code = error.code
+            effective_url = None
+            buffer.close()
+            buffer = None
+        else:
+            error = None
+            code = curl.getinfo(pycurl.HTTP_CODE)
+            effective_url = curl.getinfo(pycurl.EFFECTIVE_URL)
+            buffer.seek(0)
+        # the various curl timings are documented at
+        # http://curl.haxx.se/libcurl/c/curl_easy_getinfo.html
+        time_info = dict(
+            queue=info["curl_start_ioloop_time"] - info["queue_start_time"],
+            namelookup=curl.getinfo(pycurl.NAMELOOKUP_TIME),
+            connect=curl.getinfo(pycurl.CONNECT_TIME),
+            appconnect=curl.getinfo(pycurl.APPCONNECT_TIME),
+            pretransfer=curl.getinfo(pycurl.PRETRANSFER_TIME),
+            starttransfer=curl.getinfo(pycurl.STARTTRANSFER_TIME),
+            total=curl.getinfo(pycurl.TOTAL_TIME),
+            redirect=curl.getinfo(pycurl.REDIRECT_TIME),
+        )
+        try:
+            info["callback"](
+                HTTPResponse(
+                    request=info["request"],
+                    code=code,
+                    headers=info["headers"],
+                    buffer=buffer,
+                    effective_url=effective_url,
+                    error=error,
+                    reason=info["headers"].get("X-Http-Reason", None),
+                    request_time=self.io_loop.time() - info["curl_start_ioloop_time"],
+                    start_time=info["curl_start_time"],
+                    time_info=time_info,
+                )
+            )
+        except Exception:
+            self.handle_callback_exception(info["callback"])
+
+    def handle_callback_exception(self, callback: Any) -> None:
+        app_log.error("Exception in callback %r", callback, exc_info=True)
+
+    def _curl_create(self) -> pycurl.Curl:
+        curl = pycurl.Curl()
+        if curl_log.isEnabledFor(logging.DEBUG):
+            curl.setopt(pycurl.VERBOSE, 1)
+            curl.setopt(pycurl.DEBUGFUNCTION, self._curl_debug)
+        if hasattr(
+            pycurl, "PROTOCOLS"
+        ):  # PROTOCOLS first appeared in pycurl 7.19.5 (2014-07-12)
+            curl.setopt(pycurl.PROTOCOLS, pycurl.PROTO_HTTP | pycurl.PROTO_HTTPS)
+            curl.setopt(pycurl.REDIR_PROTOCOLS, pycurl.PROTO_HTTP | pycurl.PROTO_HTTPS)
+        return curl
+
+    def _curl_setup_request(
+        self,
+        curl: pycurl.Curl,
+        request: HTTPRequest,
+        buffer: BytesIO,
+        headers: httputil.HTTPHeaders,
+    ) -> None:
+        curl.setopt(pycurl.URL, native_str(request.url))
+
+        # libcurl's magic "Expect: 100-continue" behavior causes delays
+        # with servers that don't support it (which include, among others,
+        # Google's OpenID endpoint).  Additionally, this behavior has
+        # a bug in conjunction with the curl_multi_socket_action API
+        # (https://sourceforge.net/tracker/?func=detail&atid=100976&aid=3039744&group_id=976),
+        # which increases the delays.  It's more trouble than it's worth,
+        # so just turn off the feature (yes, setting Expect: to an empty
+        # value is the official way to disable this)
+        if "Expect" not in request.headers:
+            request.headers["Expect"] = ""
+
+        # libcurl adds Pragma: no-cache by default; disable that too
+        if "Pragma" not in request.headers:
+            request.headers["Pragma"] = ""
+
+        curl.setopt(
+            pycurl.HTTPHEADER,
+            [
+                b"%s: %s"
+                % (native_str(k).encode("ASCII"), native_str(v).encode("ISO8859-1"))
+                for k, v in request.headers.get_all()
+            ],
+        )
+
+        curl.setopt(
+            pycurl.HEADERFUNCTION,
+            functools.partial(
+                self._curl_header_callback, headers, request.header_callback
+            ),
+        )
+        if request.streaming_callback:
+
+            def write_function(b: Union[bytes, bytearray]) -> int:
+                assert request.streaming_callback is not None
+                self.io_loop.add_callback(request.streaming_callback, b)
+                return len(b)
+
+        else:
+            write_function = buffer.write  # type: ignore
+        curl.setopt(pycurl.WRITEFUNCTION, write_function)
+        curl.setopt(pycurl.FOLLOWLOCATION, request.follow_redirects)
+        curl.setopt(pycurl.MAXREDIRS, request.max_redirects)
+        assert request.connect_timeout is not None
+        curl.setopt(pycurl.CONNECTTIMEOUT_MS, int(1000 * request.connect_timeout))
+        assert request.request_timeout is not None
+        curl.setopt(pycurl.TIMEOUT_MS, int(1000 * request.request_timeout))
+        if request.user_agent:
+            curl.setopt(pycurl.USERAGENT, native_str(request.user_agent))
+        else:
+            curl.setopt(pycurl.USERAGENT, "Mozilla/5.0 (compatible; pycurl)")
+        if request.network_interface:
+            curl.setopt(pycurl.INTERFACE, request.network_interface)
+        if request.decompress_response:
+            curl.setopt(pycurl.ENCODING, "gzip,deflate")
+        else:
+            curl.setopt(pycurl.ENCODING, None)
+        if request.proxy_host and request.proxy_port:
+            curl.setopt(pycurl.PROXY, request.proxy_host)
+            curl.setopt(pycurl.PROXYPORT, request.proxy_port)
+            if request.proxy_username:
+                assert request.proxy_password is not None
+                credentials = httputil.encode_username_password(
+                    request.proxy_username, request.proxy_password
+                )
+                curl.setopt(pycurl.PROXYUSERPWD, credentials)
+
+            if request.proxy_auth_mode is None or request.proxy_auth_mode == "basic":
+                curl.setopt(pycurl.PROXYAUTH, pycurl.HTTPAUTH_BASIC)
+            elif request.proxy_auth_mode == "digest":
+                curl.setopt(pycurl.PROXYAUTH, pycurl.HTTPAUTH_DIGEST)
+            else:
+                raise ValueError(
+                    "Unsupported proxy_auth_mode %s" % request.proxy_auth_mode
+                )
+        else:
+            try:
+                curl.unsetopt(pycurl.PROXY)
+            except TypeError:  # not supported, disable proxy
+                curl.setopt(pycurl.PROXY, "")
+            curl.unsetopt(pycurl.PROXYUSERPWD)
+        if request.validate_cert:
+            curl.setopt(pycurl.SSL_VERIFYPEER, 1)
+            curl.setopt(pycurl.SSL_VERIFYHOST, 2)
+        else:
+            curl.setopt(pycurl.SSL_VERIFYPEER, 0)
+            curl.setopt(pycurl.SSL_VERIFYHOST, 0)
+        if request.ca_certs is not None:
+            curl.setopt(pycurl.CAINFO, request.ca_certs)
+        else:
+            # There is no way to restore pycurl.CAINFO to its default value
+            # (Using unsetopt makes it reject all certificates).
+            # I don't see any way to read the default value from python so it
+            # can be restored later.  We'll have to just leave CAINFO untouched
+            # if no ca_certs file was specified, and require that if any
+            # request uses a custom ca_certs file, they all must.
+            pass
+
+        if request.allow_ipv6 is False:
+            # Curl behaves reasonably when DNS resolution gives an ipv6 address
+            # that we can't reach, so allow ipv6 unless the user asks to disable.
+            curl.setopt(pycurl.IPRESOLVE, pycurl.IPRESOLVE_V4)
+        else:
+            curl.setopt(pycurl.IPRESOLVE, pycurl.IPRESOLVE_WHATEVER)
+
+        # Set the request method through curl's irritating interface which makes
+        # up names for almost every single method
+        curl_options = {
+            "GET": pycurl.HTTPGET,
+            "POST": pycurl.POST,
+            "PUT": pycurl.UPLOAD,
+            "HEAD": pycurl.NOBODY,
+        }
+        custom_methods = set(["DELETE", "OPTIONS", "PATCH"])
+        for o in curl_options.values():
+            curl.setopt(o, False)
+        if request.method in curl_options:
+            curl.unsetopt(pycurl.CUSTOMREQUEST)
+            curl.setopt(curl_options[request.method], True)
+        elif request.allow_nonstandard_methods or request.method in custom_methods:
+            curl.setopt(pycurl.CUSTOMREQUEST, request.method)
+        else:
+            raise KeyError("unknown method " + request.method)
+
+        body_expected = request.method in ("POST", "PATCH", "PUT")
+        body_present = request.body is not None
+        if not request.allow_nonstandard_methods:
+            # Some HTTP methods nearly always have bodies while others
+            # almost never do. Fail in this case unless the user has
+            # opted out of sanity checks with allow_nonstandard_methods.
+            if (body_expected and not body_present) or (
+                body_present and not body_expected
+            ):
+                raise ValueError(
+                    "Body must %sbe None for method %s (unless "
+                    "allow_nonstandard_methods is true)"
+                    % ("not " if body_expected else "", request.method)
+                )
+
+        if body_expected or body_present:
+            if request.method == "GET":
+                # Even with `allow_nonstandard_methods` we disallow
+                # GET with a body (because libcurl doesn't allow it
+                # unless we use CUSTOMREQUEST). While the spec doesn't
+                # forbid clients from sending a body, it arguably
+                # disallows the server from doing anything with them.
+                raise ValueError("Body must be None for GET request")
+            request_buffer = BytesIO(utf8(request.body or ""))
+
+            def ioctl(cmd: int) -> None:
+                if cmd == curl.IOCMD_RESTARTREAD:  # type: ignore
+                    request_buffer.seek(0)
+
+            curl.setopt(pycurl.READFUNCTION, request_buffer.read)
+            curl.setopt(pycurl.IOCTLFUNCTION, ioctl)
+            if request.method == "POST":
+                curl.setopt(pycurl.POSTFIELDSIZE, len(request.body or ""))
+            else:
+                curl.setopt(pycurl.UPLOAD, True)
+                curl.setopt(pycurl.INFILESIZE, len(request.body or ""))
+
+        if request.auth_username is not None:
+            assert request.auth_password is not None
+            if request.auth_mode is None or request.auth_mode == "basic":
+                curl.setopt(pycurl.HTTPAUTH, pycurl.HTTPAUTH_BASIC)
+            elif request.auth_mode == "digest":
+                curl.setopt(pycurl.HTTPAUTH, pycurl.HTTPAUTH_DIGEST)
+            else:
+                raise ValueError("Unsupported auth_mode %s" % request.auth_mode)
+
+            userpwd = httputil.encode_username_password(
+                request.auth_username, request.auth_password
+            )
+            curl.setopt(pycurl.USERPWD, userpwd)
+            curl_log.debug(
+                "%s %s (username: %r)",
+                request.method,
+                request.url,
+                request.auth_username,
+            )
+        else:
+            curl.unsetopt(pycurl.USERPWD)
+            curl_log.debug("%s %s", request.method, request.url)
+
+        if request.client_cert is not None:
+            curl.setopt(pycurl.SSLCERT, request.client_cert)
+
+        if request.client_key is not None:
+            curl.setopt(pycurl.SSLKEY, request.client_key)
+
+        if request.ssl_options is not None:
+            raise ValueError("ssl_options not supported in curl_httpclient")
+
+        if threading.active_count() > 1:
+            # libcurl/pycurl is not thread-safe by default.  When multiple threads
+            # are used, signals should be disabled.  This has the side effect
+            # of disabling DNS timeouts in some environments (when libcurl is
+            # not linked against ares), so we don't do it when there is only one
+            # thread.  Applications that use many short-lived threads may need
+            # to set NOSIGNAL manually in a prepare_curl_callback since
+            # there may not be any other threads running at the time we call
+            # threading.activeCount.
+            curl.setopt(pycurl.NOSIGNAL, 1)
+        if request.prepare_curl_callback is not None:
+            request.prepare_curl_callback(curl)
+
+    def _curl_header_callback(
+        self,
+        headers: httputil.HTTPHeaders,
+        header_callback: Callable[[str], None],
+        header_line_bytes: bytes,
+    ) -> None:
+        header_line = native_str(header_line_bytes.decode("latin1"))
+        if header_callback is not None:
+            self.io_loop.add_callback(header_callback, header_line)
+        # header_line as returned by curl includes the end-of-line characters.
+        # whitespace at the start should be preserved to allow multi-line headers
+        header_line = header_line.rstrip()
+        if header_line.startswith("HTTP/"):
+            headers.clear()
+            try:
+                (__, __, reason) = httputil.parse_response_start_line(header_line)
+                header_line = "X-Http-Reason: %s" % reason
+            except httputil.HTTPInputError:
+                return
+        if not header_line:
+            return
+        headers.parse_line(header_line)
+
+    def _curl_debug(self, debug_type: int, debug_msg: str) -> None:
+        debug_types = ("I", "<", ">", "<", ">")
+        if debug_type == 0:
+            debug_msg = native_str(debug_msg)
+            curl_log.debug("%s", debug_msg.strip())
+        elif debug_type in (1, 2):
+            debug_msg = native_str(debug_msg)
+            for line in debug_msg.splitlines():
+                curl_log.debug("%s %s", debug_types[debug_type], line)
+        elif debug_type == 4:
+            curl_log.debug("%s %r", debug_types[debug_type], debug_msg)
+
+
+class CurlError(HTTPError):
+    def __init__(self, errno: int, message: str) -> None:
+        HTTPError.__init__(self, 599, message)
+        self.errno = errno
+
+
+if __name__ == "__main__":
+    AsyncHTTPClient.configure(CurlAsyncHTTPClient)
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/escape.py b/venv/lib/python3.9/site-packages/tornado/escape.py
new file mode 100644
index 00000000..55354c30
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/escape.py
@@ -0,0 +1,402 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Escaping/unescaping methods for HTML, JSON, URLs, and others.
+
+Also includes a few other miscellaneous string manipulation functions that
+have crept in over time.
+"""
+
+import html.entities
+import json
+import re
+import urllib.parse
+
+from tornado.util import unicode_type
+
+import typing
+from typing import Union, Any, Optional, Dict, List, Callable
+
+
+_XHTML_ESCAPE_RE = re.compile("[&<>\"']")
+_XHTML_ESCAPE_DICT = {
+    "&": "&amp;",
+    "<": "&lt;",
+    ">": "&gt;",
+    '"': "&quot;",
+    "'": "&#39;",
+}
+
+
+def xhtml_escape(value: Union[str, bytes]) -> str:
+    """Escapes a string so it is valid within HTML or XML.
+
+    Escapes the characters ``<``, ``>``, ``"``, ``'``, and ``&``.
+    When used in attribute values the escaped strings must be enclosed
+    in quotes.
+
+    .. versionchanged:: 3.2
+
+       Added the single quote to the list of escaped characters.
+    """
+    return _XHTML_ESCAPE_RE.sub(
+        lambda match: _XHTML_ESCAPE_DICT[match.group(0)], to_basestring(value)
+    )
+
+
+def xhtml_unescape(value: Union[str, bytes]) -> str:
+    """Un-escapes an XML-escaped string."""
+    return re.sub(r"&(#?)(\w+?);", _convert_entity, _unicode(value))
+
+
+# The fact that json_encode wraps json.dumps is an implementation detail.
+# Please see https://github.com/tornadoweb/tornado/pull/706
+# before sending a pull request that adds **kwargs to this function.
+def json_encode(value: Any) -> str:
+    """JSON-encodes the given Python object."""
+    # JSON permits but does not require forward slashes to be escaped.
+    # This is useful when json data is emitted in a <script> tag
+    # in HTML, as it prevents </script> tags from prematurely terminating
+    # the JavaScript.  Some json libraries do this escaping by default,
+    # although python's standard library does not, so we do it here.
+    # http://stackoverflow.com/questions/1580647/json-why-are-forward-slashes-escaped
+    return json.dumps(value).replace("</", "<\\/")
+
+
+def json_decode(value: Union[str, bytes]) -> Any:
+    """Returns Python objects for the given JSON string.
+
+    Supports both `str` and `bytes` inputs.
+    """
+    return json.loads(to_basestring(value))
+
+
+def squeeze(value: str) -> str:
+    """Replace all sequences of whitespace chars with a single space."""
+    return re.sub(r"[\x00-\x20]+", " ", value).strip()
+
+
+def url_escape(value: Union[str, bytes], plus: bool = True) -> str:
+    """Returns a URL-encoded version of the given value.
+
+    If ``plus`` is true (the default), spaces will be represented
+    as "+" instead of "%20".  This is appropriate for query strings
+    but not for the path component of a URL.  Note that this default
+    is the reverse of Python's urllib module.
+
+    .. versionadded:: 3.1
+        The ``plus`` argument
+    """
+    quote = urllib.parse.quote_plus if plus else urllib.parse.quote
+    return quote(utf8(value))
+
+
+@typing.overload
+def url_unescape(value: Union[str, bytes], encoding: None, plus: bool = True) -> bytes:
+    pass
+
+
+@typing.overload  # noqa: F811
+def url_unescape(
+    value: Union[str, bytes], encoding: str = "utf-8", plus: bool = True
+) -> str:
+    pass
+
+
+def url_unescape(  # noqa: F811
+    value: Union[str, bytes], encoding: Optional[str] = "utf-8", plus: bool = True
+) -> Union[str, bytes]:
+    """Decodes the given value from a URL.
+
+    The argument may be either a byte or unicode string.
+
+    If encoding is None, the result will be a byte string.  Otherwise,
+    the result is a unicode string in the specified encoding.
+
+    If ``plus`` is true (the default), plus signs will be interpreted
+    as spaces (literal plus signs must be represented as "%2B").  This
+    is appropriate for query strings and form-encoded values but not
+    for the path component of a URL.  Note that this default is the
+    reverse of Python's urllib module.
+
+    .. versionadded:: 3.1
+       The ``plus`` argument
+    """
+    if encoding is None:
+        if plus:
+            # unquote_to_bytes doesn't have a _plus variant
+            value = to_basestring(value).replace("+", " ")
+        return urllib.parse.unquote_to_bytes(value)
+    else:
+        unquote = urllib.parse.unquote_plus if plus else urllib.parse.unquote
+        return unquote(to_basestring(value), encoding=encoding)
+
+
+def parse_qs_bytes(
+    qs: Union[str, bytes], keep_blank_values: bool = False, strict_parsing: bool = False
+) -> Dict[str, List[bytes]]:
+    """Parses a query string like urlparse.parse_qs,
+    but takes bytes and returns the values as byte strings.
+
+    Keys still become type str (interpreted as latin1 in python3!)
+    because it's too painful to keep them as byte strings in
+    python3 and in practice they're nearly always ascii anyway.
+    """
+    # This is gross, but python3 doesn't give us another way.
+    # Latin1 is the universal donor of character encodings.
+    if isinstance(qs, bytes):
+        qs = qs.decode("latin1")
+    result = urllib.parse.parse_qs(
+        qs, keep_blank_values, strict_parsing, encoding="latin1", errors="strict"
+    )
+    encoded = {}
+    for k, v in result.items():
+        encoded[k] = [i.encode("latin1") for i in v]
+    return encoded
+
+
+_UTF8_TYPES = (bytes, type(None))
+
+
+@typing.overload
+def utf8(value: bytes) -> bytes:
+    pass
+
+
+@typing.overload  # noqa: F811
+def utf8(value: str) -> bytes:
+    pass
+
+
+@typing.overload  # noqa: F811
+def utf8(value: None) -> None:
+    pass
+
+
+def utf8(value: Union[None, str, bytes]) -> Optional[bytes]:  # noqa: F811
+    """Converts a string argument to a byte string.
+
+    If the argument is already a byte string or None, it is returned unchanged.
+    Otherwise it must be a unicode string and is encoded as utf8.
+    """
+    if isinstance(value, _UTF8_TYPES):
+        return value
+    if not isinstance(value, unicode_type):
+        raise TypeError("Expected bytes, unicode, or None; got %r" % type(value))
+    return value.encode("utf-8")
+
+
+_TO_UNICODE_TYPES = (unicode_type, type(None))
+
+
+@typing.overload
+def to_unicode(value: str) -> str:
+    pass
+
+
+@typing.overload  # noqa: F811
+def to_unicode(value: bytes) -> str:
+    pass
+
+
+@typing.overload  # noqa: F811
+def to_unicode(value: None) -> None:
+    pass
+
+
+def to_unicode(value: Union[None, str, bytes]) -> Optional[str]:  # noqa: F811
+    """Converts a string argument to a unicode string.
+
+    If the argument is already a unicode string or None, it is returned
+    unchanged.  Otherwise it must be a byte string and is decoded as utf8.
+    """
+    if isinstance(value, _TO_UNICODE_TYPES):
+        return value
+    if not isinstance(value, bytes):
+        raise TypeError("Expected bytes, unicode, or None; got %r" % type(value))
+    return value.decode("utf-8")
+
+
+# to_unicode was previously named _unicode not because it was private,
+# but to avoid conflicts with the built-in unicode() function/type
+_unicode = to_unicode
+
+# When dealing with the standard library across python 2 and 3 it is
+# sometimes useful to have a direct conversion to the native string type
+native_str = to_unicode
+to_basestring = to_unicode
+
+
+def recursive_unicode(obj: Any) -> Any:
+    """Walks a simple data structure, converting byte strings to unicode.
+
+    Supports lists, tuples, and dictionaries.
+    """
+    if isinstance(obj, dict):
+        return dict(
+            (recursive_unicode(k), recursive_unicode(v)) for (k, v) in obj.items()
+        )
+    elif isinstance(obj, list):
+        return list(recursive_unicode(i) for i in obj)
+    elif isinstance(obj, tuple):
+        return tuple(recursive_unicode(i) for i in obj)
+    elif isinstance(obj, bytes):
+        return to_unicode(obj)
+    else:
+        return obj
+
+
+# I originally used the regex from
+# http://daringfireball.net/2010/07/improved_regex_for_matching_urls
+# but it gets all exponential on certain patterns (such as too many trailing
+# dots), causing the regex matcher to never return.
+# This regex should avoid those problems.
+# Use to_unicode instead of tornado.util.u - we don't want backslashes getting
+# processed as escapes.
+_URL_RE = re.compile(
+    to_unicode(
+        r"""\b((?:([\w-]+):(/{1,3})|www[.])(?:(?:(?:[^\s&()]|&amp;|&quot;)*(?:[^!"#$%&'()*+,.:;<=>?@\[\]^`{|}~\s]))|(?:\((?:[^\s&()]|&amp;|&quot;)*\)))+)"""  # noqa: E501
+    )
+)
+
+
+def linkify(
+    text: Union[str, bytes],
+    shorten: bool = False,
+    extra_params: Union[str, Callable[[str], str]] = "",
+    require_protocol: bool = False,
+    permitted_protocols: List[str] = ["http", "https"],
+) -> str:
+    """Converts plain text into HTML with links.
+
+    For example: ``linkify("Hello http://tornadoweb.org!")`` would return
+    ``Hello <a href="http://tornadoweb.org">http://tornadoweb.org</a>!``
+
+    Parameters:
+
+    * ``shorten``: Long urls will be shortened for display.
+
+    * ``extra_params``: Extra text to include in the link tag, or a callable
+      taking the link as an argument and returning the extra text
+      e.g. ``linkify(text, extra_params='rel="nofollow" class="external"')``,
+      or::
+
+          def extra_params_cb(url):
+              if url.startswith("http://example.com"):
+                  return 'class="internal"'
+              else:
+                  return 'class="external" rel="nofollow"'
+          linkify(text, extra_params=extra_params_cb)
+
+    * ``require_protocol``: Only linkify urls which include a protocol. If
+      this is False, urls such as www.facebook.com will also be linkified.
+
+    * ``permitted_protocols``: List (or set) of protocols which should be
+      linkified, e.g. ``linkify(text, permitted_protocols=["http", "ftp",
+      "mailto"])``. It is very unsafe to include protocols such as
+      ``javascript``.
+    """
+    if extra_params and not callable(extra_params):
+        extra_params = " " + extra_params.strip()
+
+    def make_link(m: typing.Match) -> str:
+        url = m.group(1)
+        proto = m.group(2)
+        if require_protocol and not proto:
+            return url  # not protocol, no linkify
+
+        if proto and proto not in permitted_protocols:
+            return url  # bad protocol, no linkify
+
+        href = m.group(1)
+        if not proto:
+            href = "http://" + href  # no proto specified, use http
+
+        if callable(extra_params):
+            params = " " + extra_params(href).strip()
+        else:
+            params = extra_params
+
+        # clip long urls. max_len is just an approximation
+        max_len = 30
+        if shorten and len(url) > max_len:
+            before_clip = url
+            if proto:
+                proto_len = len(proto) + 1 + len(m.group(3) or "")  # +1 for :
+            else:
+                proto_len = 0
+
+            parts = url[proto_len:].split("/")
+            if len(parts) > 1:
+                # Grab the whole host part plus the first bit of the path
+                # The path is usually not that interesting once shortened
+                # (no more slug, etc), so it really just provides a little
+                # extra indication of shortening.
+                url = (
+                    url[:proto_len]
+                    + parts[0]
+                    + "/"
+                    + parts[1][:8].split("?")[0].split(".")[0]
+                )
+
+            if len(url) > max_len * 1.5:  # still too long
+                url = url[:max_len]
+
+            if url != before_clip:
+                amp = url.rfind("&")
+                # avoid splitting html char entities
+                if amp > max_len - 5:
+                    url = url[:amp]
+                url += "..."
+
+                if len(url) >= len(before_clip):
+                    url = before_clip
+                else:
+                    # full url is visible on mouse-over (for those who don't
+                    # have a status bar, such as Safari by default)
+                    params += ' title="%s"' % href
+
+        return '<a href="%s"%s>%s</a>' % (href, params, url)
+
+    # First HTML-escape so that our strings are all safe.
+    # The regex is modified to avoid character entites other than &amp; so
+    # that we won't pick up &quot;, etc.
+    text = _unicode(xhtml_escape(text))
+    return _URL_RE.sub(make_link, text)
+
+
+def _convert_entity(m: typing.Match) -> str:
+    if m.group(1) == "#":
+        try:
+            if m.group(2)[:1].lower() == "x":
+                return chr(int(m.group(2)[1:], 16))
+            else:
+                return chr(int(m.group(2)))
+        except ValueError:
+            return "&#%s;" % m.group(2)
+    try:
+        return _HTML_UNICODE_MAP[m.group(2)]
+    except KeyError:
+        return "&%s;" % m.group(2)
+
+
+def _build_unicode_map() -> Dict[str, str]:
+    unicode_map = {}
+    for name, value in html.entities.name2codepoint.items():
+        unicode_map[name] = chr(value)
+    return unicode_map
+
+
+_HTML_UNICODE_MAP = _build_unicode_map()
diff --git a/venv/lib/python3.9/site-packages/tornado/gen.py b/venv/lib/python3.9/site-packages/tornado/gen.py
new file mode 100644
index 00000000..4819b857
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/gen.py
@@ -0,0 +1,883 @@
+"""``tornado.gen`` implements generator-based coroutines.
+
+.. note::
+
+   The "decorator and generator" approach in this module is a
+   precursor to native coroutines (using ``async def`` and ``await``)
+   which were introduced in Python 3.5. Applications that do not
+   require compatibility with older versions of Python should use
+   native coroutines instead. Some parts of this module are still
+   useful with native coroutines, notably `multi`, `sleep`,
+   `WaitIterator`, and `with_timeout`. Some of these functions have
+   counterparts in the `asyncio` module which may be used as well,
+   although the two may not necessarily be 100% compatible.
+
+Coroutines provide an easier way to work in an asynchronous
+environment than chaining callbacks. Code using coroutines is
+technically asynchronous, but it is written as a single generator
+instead of a collection of separate functions.
+
+For example, here's a coroutine-based handler:
+
+.. testcode::
+
+    class GenAsyncHandler(RequestHandler):
+        @gen.coroutine
+        def get(self):
+            http_client = AsyncHTTPClient()
+            response = yield http_client.fetch("http://example.com")
+            do_something_with_response(response)
+            self.render("template.html")
+
+.. testoutput::
+   :hide:
+
+Asynchronous functions in Tornado return an ``Awaitable`` or `.Future`;
+yielding this object returns its result.
+
+You can also yield a list or dict of other yieldable objects, which
+will be started at the same time and run in parallel; a list or dict
+of results will be returned when they are all finished:
+
+.. testcode::
+
+    @gen.coroutine
+    def get(self):
+        http_client = AsyncHTTPClient()
+        response1, response2 = yield [http_client.fetch(url1),
+                                      http_client.fetch(url2)]
+        response_dict = yield dict(response3=http_client.fetch(url3),
+                                   response4=http_client.fetch(url4))
+        response3 = response_dict['response3']
+        response4 = response_dict['response4']
+
+.. testoutput::
+   :hide:
+
+If ``tornado.platform.twisted`` is imported, it is also possible to
+yield Twisted's ``Deferred`` objects. See the `convert_yielded`
+function to extend this mechanism.
+
+.. versionchanged:: 3.2
+   Dict support added.
+
+.. versionchanged:: 4.1
+   Support added for yielding ``asyncio`` Futures and Twisted Deferreds
+   via ``singledispatch``.
+
+"""
+import asyncio
+import builtins
+import collections
+from collections.abc import Generator
+import concurrent.futures
+import datetime
+import functools
+from functools import singledispatch
+from inspect import isawaitable
+import sys
+import types
+
+from tornado.concurrent import (
+    Future,
+    is_future,
+    chain_future,
+    future_set_exc_info,
+    future_add_done_callback,
+    future_set_result_unless_cancelled,
+)
+from tornado.ioloop import IOLoop
+from tornado.log import app_log
+from tornado.util import TimeoutError
+
+try:
+    import contextvars
+except ImportError:
+    contextvars = None  # type: ignore
+
+import typing
+from typing import Union, Any, Callable, List, Type, Tuple, Awaitable, Dict, overload
+
+if typing.TYPE_CHECKING:
+    from typing import Sequence, Deque, Optional, Set, Iterable  # noqa: F401
+
+_T = typing.TypeVar("_T")
+
+_Yieldable = Union[
+    None, Awaitable, List[Awaitable], Dict[Any, Awaitable], concurrent.futures.Future
+]
+
+
+class KeyReuseError(Exception):
+    pass
+
+
+class UnknownKeyError(Exception):
+    pass
+
+
+class LeakedCallbackError(Exception):
+    pass
+
+
+class BadYieldError(Exception):
+    pass
+
+
+class ReturnValueIgnoredError(Exception):
+    pass
+
+
+def _value_from_stopiteration(e: Union[StopIteration, "Return"]) -> Any:
+    try:
+        # StopIteration has a value attribute beginning in py33.
+        # So does our Return class.
+        return e.value
+    except AttributeError:
+        pass
+    try:
+        # Cython backports coroutine functionality by putting the value in
+        # e.args[0].
+        return e.args[0]
+    except (AttributeError, IndexError):
+        return None
+
+
+def _create_future() -> Future:
+    future = Future()  # type: Future
+    # Fixup asyncio debug info by removing extraneous stack entries
+    source_traceback = getattr(future, "_source_traceback", ())
+    while source_traceback:
+        # Each traceback entry is equivalent to a
+        # (filename, self.lineno, self.name, self.line) tuple
+        filename = source_traceback[-1][0]
+        if filename == __file__:
+            del source_traceback[-1]
+        else:
+            break
+    return future
+
+
+def _fake_ctx_run(f: Callable[..., _T], *args: Any, **kw: Any) -> _T:
+    return f(*args, **kw)
+
+
+@overload
+def coroutine(
+    func: Callable[..., "Generator[Any, Any, _T]"]
+) -> Callable[..., "Future[_T]"]:
+    ...
+
+
+@overload
+def coroutine(func: Callable[..., _T]) -> Callable[..., "Future[_T]"]:
+    ...
+
+
+def coroutine(
+    func: Union[Callable[..., "Generator[Any, Any, _T]"], Callable[..., _T]]
+) -> Callable[..., "Future[_T]"]:
+    """Decorator for asynchronous generators.
+
+    For compatibility with older versions of Python, coroutines may
+    also "return" by raising the special exception `Return(value)
+    <Return>`.
+
+    Functions with this decorator return a `.Future`.
+
+    .. warning::
+
+       When exceptions occur inside a coroutine, the exception
+       information will be stored in the `.Future` object. You must
+       examine the result of the `.Future` object, or the exception
+       may go unnoticed by your code. This means yielding the function
+       if called from another coroutine, using something like
+       `.IOLoop.run_sync` for top-level calls, or passing the `.Future`
+       to `.IOLoop.add_future`.
+
+    .. versionchanged:: 6.0
+
+       The ``callback`` argument was removed. Use the returned
+       awaitable object instead.
+
+    """
+
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        # type: (*Any, **Any) -> Future[_T]
+        # This function is type-annotated with a comment to work around
+        # https://bitbucket.org/pypy/pypy/issues/2868/segfault-with-args-type-annotation-in
+        future = _create_future()
+        if contextvars is not None:
+            ctx_run = contextvars.copy_context().run  # type: Callable
+        else:
+            ctx_run = _fake_ctx_run
+        try:
+            result = ctx_run(func, *args, **kwargs)
+        except (Return, StopIteration) as e:
+            result = _value_from_stopiteration(e)
+        except Exception:
+            future_set_exc_info(future, sys.exc_info())
+            try:
+                return future
+            finally:
+                # Avoid circular references
+                future = None  # type: ignore
+        else:
+            if isinstance(result, Generator):
+                # Inline the first iteration of Runner.run.  This lets us
+                # avoid the cost of creating a Runner when the coroutine
+                # never actually yields, which in turn allows us to
+                # use "optional" coroutines in critical path code without
+                # performance penalty for the synchronous case.
+                try:
+                    yielded = ctx_run(next, result)
+                except (StopIteration, Return) as e:
+                    future_set_result_unless_cancelled(
+                        future, _value_from_stopiteration(e)
+                    )
+                except Exception:
+                    future_set_exc_info(future, sys.exc_info())
+                else:
+                    # Provide strong references to Runner objects as long
+                    # as their result future objects also have strong
+                    # references (typically from the parent coroutine's
+                    # Runner). This keeps the coroutine's Runner alive.
+                    # We do this by exploiting the public API
+                    # add_done_callback() instead of putting a private
+                    # attribute on the Future.
+                    # (GitHub issues #1769, #2229).
+                    runner = Runner(ctx_run, result, future, yielded)
+                    future.add_done_callback(lambda _: runner)
+                yielded = None
+                try:
+                    return future
+                finally:
+                    # Subtle memory optimization: if next() raised an exception,
+                    # the future's exc_info contains a traceback which
+                    # includes this stack frame.  This creates a cycle,
+                    # which will be collected at the next full GC but has
+                    # been shown to greatly increase memory usage of
+                    # benchmarks (relative to the refcount-based scheme
+                    # used in the absence of cycles).  We can avoid the
+                    # cycle by clearing the local variable after we return it.
+                    future = None  # type: ignore
+        future_set_result_unless_cancelled(future, result)
+        return future
+
+    wrapper.__wrapped__ = func  # type: ignore
+    wrapper.__tornado_coroutine__ = True  # type: ignore
+    return wrapper
+
+
+def is_coroutine_function(func: Any) -> bool:
+    """Return whether *func* is a coroutine function, i.e. a function
+    wrapped with `~.gen.coroutine`.
+
+    .. versionadded:: 4.5
+    """
+    return getattr(func, "__tornado_coroutine__", False)
+
+
+class Return(Exception):
+    """Special exception to return a value from a `coroutine`.
+
+    If this exception is raised, its value argument is used as the
+    result of the coroutine::
+
+        @gen.coroutine
+        def fetch_json(url):
+            response = yield AsyncHTTPClient().fetch(url)
+            raise gen.Return(json_decode(response.body))
+
+    In Python 3.3, this exception is no longer necessary: the ``return``
+    statement can be used directly to return a value (previously
+    ``yield`` and ``return`` with a value could not be combined in the
+    same function).
+
+    By analogy with the return statement, the value argument is optional,
+    but it is never necessary to ``raise gen.Return()``.  The ``return``
+    statement can be used with no arguments instead.
+    """
+
+    def __init__(self, value: Any = None) -> None:
+        super().__init__()
+        self.value = value
+        # Cython recognizes subclasses of StopIteration with a .args tuple.
+        self.args = (value,)
+
+
+class WaitIterator(object):
+    """Provides an iterator to yield the results of awaitables as they finish.
+
+    Yielding a set of awaitables like this:
+
+    ``results = yield [awaitable1, awaitable2]``
+
+    pauses the coroutine until both ``awaitable1`` and ``awaitable2``
+    return, and then restarts the coroutine with the results of both
+    awaitables. If either awaitable raises an exception, the
+    expression will raise that exception and all the results will be
+    lost.
+
+    If you need to get the result of each awaitable as soon as possible,
+    or if you need the result of some awaitables even if others produce
+    errors, you can use ``WaitIterator``::
+
+      wait_iterator = gen.WaitIterator(awaitable1, awaitable2)
+      while not wait_iterator.done():
+          try:
+              result = yield wait_iterator.next()
+          except Exception as e:
+              print("Error {} from {}".format(e, wait_iterator.current_future))
+          else:
+              print("Result {} received from {} at {}".format(
+                  result, wait_iterator.current_future,
+                  wait_iterator.current_index))
+
+    Because results are returned as soon as they are available the
+    output from the iterator *will not be in the same order as the
+    input arguments*. If you need to know which future produced the
+    current result, you can use the attributes
+    ``WaitIterator.current_future``, or ``WaitIterator.current_index``
+    to get the index of the awaitable from the input list. (if keyword
+    arguments were used in the construction of the `WaitIterator`,
+    ``current_index`` will use the corresponding keyword).
+
+    On Python 3.5, `WaitIterator` implements the async iterator
+    protocol, so it can be used with the ``async for`` statement (note
+    that in this version the entire iteration is aborted if any value
+    raises an exception, while the previous example can continue past
+    individual errors)::
+
+      async for result in gen.WaitIterator(future1, future2):
+          print("Result {} received from {} at {}".format(
+              result, wait_iterator.current_future,
+              wait_iterator.current_index))
+
+    .. versionadded:: 4.1
+
+    .. versionchanged:: 4.3
+       Added ``async for`` support in Python 3.5.
+
+    """
+
+    _unfinished = {}  # type: Dict[Future, Union[int, str]]
+
+    def __init__(self, *args: Future, **kwargs: Future) -> None:
+        if args and kwargs:
+            raise ValueError("You must provide args or kwargs, not both")
+
+        if kwargs:
+            self._unfinished = dict((f, k) for (k, f) in kwargs.items())
+            futures = list(kwargs.values())  # type: Sequence[Future]
+        else:
+            self._unfinished = dict((f, i) for (i, f) in enumerate(args))
+            futures = args
+
+        self._finished = collections.deque()  # type: Deque[Future]
+        self.current_index = None  # type: Optional[Union[str, int]]
+        self.current_future = None  # type: Optional[Future]
+        self._running_future = None  # type: Optional[Future]
+
+        for future in futures:
+            future_add_done_callback(future, self._done_callback)
+
+    def done(self) -> bool:
+        """Returns True if this iterator has no more results."""
+        if self._finished or self._unfinished:
+            return False
+        # Clear the 'current' values when iteration is done.
+        self.current_index = self.current_future = None
+        return True
+
+    def next(self) -> Future:
+        """Returns a `.Future` that will yield the next available result.
+
+        Note that this `.Future` will not be the same object as any of
+        the inputs.
+        """
+        self._running_future = Future()
+
+        if self._finished:
+            return self._return_result(self._finished.popleft())
+
+        return self._running_future
+
+    def _done_callback(self, done: Future) -> None:
+        if self._running_future and not self._running_future.done():
+            self._return_result(done)
+        else:
+            self._finished.append(done)
+
+    def _return_result(self, done: Future) -> Future:
+        """Called set the returned future's state that of the future
+        we yielded, and set the current future for the iterator.
+        """
+        if self._running_future is None:
+            raise Exception("no future is running")
+        chain_future(done, self._running_future)
+
+        res = self._running_future
+        self._running_future = None
+        self.current_future = done
+        self.current_index = self._unfinished.pop(done)
+
+        return res
+
+    def __aiter__(self) -> typing.AsyncIterator:
+        return self
+
+    def __anext__(self) -> Future:
+        if self.done():
+            # Lookup by name to silence pyflakes on older versions.
+            raise getattr(builtins, "StopAsyncIteration")()
+        return self.next()
+
+
+def multi(
+    children: Union[List[_Yieldable], Dict[Any, _Yieldable]],
+    quiet_exceptions: "Union[Type[Exception], Tuple[Type[Exception], ...]]" = (),
+) -> "Union[Future[List], Future[Dict]]":
+    """Runs multiple asynchronous operations in parallel.
+
+    ``children`` may either be a list or a dict whose values are
+    yieldable objects. ``multi()`` returns a new yieldable
+    object that resolves to a parallel structure containing their
+    results. If ``children`` is a list, the result is a list of
+    results in the same order; if it is a dict, the result is a dict
+    with the same keys.
+
+    That is, ``results = yield multi(list_of_futures)`` is equivalent
+    to::
+
+        results = []
+        for future in list_of_futures:
+            results.append(yield future)
+
+    If any children raise exceptions, ``multi()`` will raise the first
+    one. All others will be logged, unless they are of types
+    contained in the ``quiet_exceptions`` argument.
+
+    In a ``yield``-based coroutine, it is not normally necessary to
+    call this function directly, since the coroutine runner will
+    do it automatically when a list or dict is yielded. However,
+    it is necessary in ``await``-based coroutines, or to pass
+    the ``quiet_exceptions`` argument.
+
+    This function is available under the names ``multi()`` and ``Multi()``
+    for historical reasons.
+
+    Cancelling a `.Future` returned by ``multi()`` does not cancel its
+    children. `asyncio.gather` is similar to ``multi()``, but it does
+    cancel its children.
+
+    .. versionchanged:: 4.2
+       If multiple yieldables fail, any exceptions after the first
+       (which is raised) will be logged. Added the ``quiet_exceptions``
+       argument to suppress this logging for selected exception types.
+
+    .. versionchanged:: 4.3
+       Replaced the class ``Multi`` and the function ``multi_future``
+       with a unified function ``multi``. Added support for yieldables
+       other than ``YieldPoint`` and `.Future`.
+
+    """
+    return multi_future(children, quiet_exceptions=quiet_exceptions)
+
+
+Multi = multi
+
+
+def multi_future(
+    children: Union[List[_Yieldable], Dict[Any, _Yieldable]],
+    quiet_exceptions: "Union[Type[Exception], Tuple[Type[Exception], ...]]" = (),
+) -> "Union[Future[List], Future[Dict]]":
+    """Wait for multiple asynchronous futures in parallel.
+
+    Since Tornado 6.0, this function is exactly the same as `multi`.
+
+    .. versionadded:: 4.0
+
+    .. versionchanged:: 4.2
+       If multiple ``Futures`` fail, any exceptions after the first (which is
+       raised) will be logged. Added the ``quiet_exceptions``
+       argument to suppress this logging for selected exception types.
+
+    .. deprecated:: 4.3
+       Use `multi` instead.
+    """
+    if isinstance(children, dict):
+        keys = list(children.keys())  # type: Optional[List]
+        children_seq = children.values()  # type: Iterable
+    else:
+        keys = None
+        children_seq = children
+    children_futs = list(map(convert_yielded, children_seq))
+    assert all(is_future(i) or isinstance(i, _NullFuture) for i in children_futs)
+    unfinished_children = set(children_futs)
+
+    future = _create_future()
+    if not children_futs:
+        future_set_result_unless_cancelled(future, {} if keys is not None else [])
+
+    def callback(fut: Future) -> None:
+        unfinished_children.remove(fut)
+        if not unfinished_children:
+            result_list = []
+            for f in children_futs:
+                try:
+                    result_list.append(f.result())
+                except Exception as e:
+                    if future.done():
+                        if not isinstance(e, quiet_exceptions):
+                            app_log.error(
+                                "Multiple exceptions in yield list", exc_info=True
+                            )
+                    else:
+                        future_set_exc_info(future, sys.exc_info())
+            if not future.done():
+                if keys is not None:
+                    future_set_result_unless_cancelled(
+                        future, dict(zip(keys, result_list))
+                    )
+                else:
+                    future_set_result_unless_cancelled(future, result_list)
+
+    listening = set()  # type: Set[Future]
+    for f in children_futs:
+        if f not in listening:
+            listening.add(f)
+            future_add_done_callback(f, callback)
+    return future
+
+
+def maybe_future(x: Any) -> Future:
+    """Converts ``x`` into a `.Future`.
+
+    If ``x`` is already a `.Future`, it is simply returned; otherwise
+    it is wrapped in a new `.Future`.  This is suitable for use as
+    ``result = yield gen.maybe_future(f())`` when you don't know whether
+    ``f()`` returns a `.Future` or not.
+
+    .. deprecated:: 4.3
+       This function only handles ``Futures``, not other yieldable objects.
+       Instead of `maybe_future`, check for the non-future result types
+       you expect (often just ``None``), and ``yield`` anything unknown.
+    """
+    if is_future(x):
+        return x
+    else:
+        fut = _create_future()
+        fut.set_result(x)
+        return fut
+
+
+def with_timeout(
+    timeout: Union[float, datetime.timedelta],
+    future: _Yieldable,
+    quiet_exceptions: "Union[Type[Exception], Tuple[Type[Exception], ...]]" = (),
+) -> Future:
+    """Wraps a `.Future` (or other yieldable object) in a timeout.
+
+    Raises `tornado.util.TimeoutError` if the input future does not
+    complete before ``timeout``, which may be specified in any form
+    allowed by `.IOLoop.add_timeout` (i.e. a `datetime.timedelta` or
+    an absolute time relative to `.IOLoop.time`)
+
+    If the wrapped `.Future` fails after it has timed out, the exception
+    will be logged unless it is either of a type contained in
+    ``quiet_exceptions`` (which may be an exception type or a sequence of
+    types), or an ``asyncio.CancelledError``.
+
+    The wrapped `.Future` is not canceled when the timeout expires,
+    permitting it to be reused. `asyncio.wait_for` is similar to this
+    function but it does cancel the wrapped `.Future` on timeout.
+
+    .. versionadded:: 4.0
+
+    .. versionchanged:: 4.1
+       Added the ``quiet_exceptions`` argument and the logging of unhandled
+       exceptions.
+
+    .. versionchanged:: 4.4
+       Added support for yieldable objects other than `.Future`.
+
+    .. versionchanged:: 6.0.3
+       ``asyncio.CancelledError`` is now always considered "quiet".
+
+    .. versionchanged:: 6.2
+       ``tornado.util.TimeoutError`` is now an alias to ``asyncio.TimeoutError``.
+
+    """
+    # It's tempting to optimize this by cancelling the input future on timeout
+    # instead of creating a new one, but A) we can't know if we are the only
+    # one waiting on the input future, so cancelling it might disrupt other
+    # callers and B) concurrent futures can only be cancelled while they are
+    # in the queue, so cancellation cannot reliably bound our waiting time.
+    future_converted = convert_yielded(future)
+    result = _create_future()
+    chain_future(future_converted, result)
+    io_loop = IOLoop.current()
+
+    def error_callback(future: Future) -> None:
+        try:
+            future.result()
+        except asyncio.CancelledError:
+            pass
+        except Exception as e:
+            if not isinstance(e, quiet_exceptions):
+                app_log.error(
+                    "Exception in Future %r after timeout", future, exc_info=True
+                )
+
+    def timeout_callback() -> None:
+        if not result.done():
+            result.set_exception(TimeoutError("Timeout"))
+        # In case the wrapped future goes on to fail, log it.
+        future_add_done_callback(future_converted, error_callback)
+
+    timeout_handle = io_loop.add_timeout(timeout, timeout_callback)
+    if isinstance(future_converted, Future):
+        # We know this future will resolve on the IOLoop, so we don't
+        # need the extra thread-safety of IOLoop.add_future (and we also
+        # don't care about StackContext here.
+        future_add_done_callback(
+            future_converted, lambda future: io_loop.remove_timeout(timeout_handle)
+        )
+    else:
+        # concurrent.futures.Futures may resolve on any thread, so we
+        # need to route them back to the IOLoop.
+        io_loop.add_future(
+            future_converted, lambda future: io_loop.remove_timeout(timeout_handle)
+        )
+    return result
+
+
+def sleep(duration: float) -> "Future[None]":
+    """Return a `.Future` that resolves after the given number of seconds.
+
+    When used with ``yield`` in a coroutine, this is a non-blocking
+    analogue to `time.sleep` (which should not be used in coroutines
+    because it is blocking)::
+
+        yield gen.sleep(0.5)
+
+    Note that calling this function on its own does nothing; you must
+    wait on the `.Future` it returns (usually by yielding it).
+
+    .. versionadded:: 4.1
+    """
+    f = _create_future()
+    IOLoop.current().call_later(
+        duration, lambda: future_set_result_unless_cancelled(f, None)
+    )
+    return f
+
+
+class _NullFuture(object):
+    """_NullFuture resembles a Future that finished with a result of None.
+
+    It's not actually a `Future` to avoid depending on a particular event loop.
+    Handled as a special case in the coroutine runner.
+
+    We lie and tell the type checker that a _NullFuture is a Future so
+    we don't have to leak _NullFuture into lots of public APIs. But
+    this means that the type checker can't warn us when we're passing
+    a _NullFuture into a code path that doesn't understand what to do
+    with it.
+    """
+
+    def result(self) -> None:
+        return None
+
+    def done(self) -> bool:
+        return True
+
+
+# _null_future is used as a dummy value in the coroutine runner. It differs
+# from moment in that moment always adds a delay of one IOLoop iteration
+# while _null_future is processed as soon as possible.
+_null_future = typing.cast(Future, _NullFuture())
+
+moment = typing.cast(Future, _NullFuture())
+moment.__doc__ = """A special object which may be yielded to allow the IOLoop to run for
+one iteration.
+
+This is not needed in normal use but it can be helpful in long-running
+coroutines that are likely to yield Futures that are ready instantly.
+
+Usage: ``yield gen.moment``
+
+In native coroutines, the equivalent of ``yield gen.moment`` is
+``await asyncio.sleep(0)``.
+
+.. versionadded:: 4.0
+
+.. deprecated:: 4.5
+   ``yield None`` (or ``yield`` with no argument) is now equivalent to
+    ``yield gen.moment``.
+"""
+
+
+class Runner(object):
+    """Internal implementation of `tornado.gen.coroutine`.
+
+    Maintains information about pending callbacks and their results.
+
+    The results of the generator are stored in ``result_future`` (a
+    `.Future`)
+    """
+
+    def __init__(
+        self,
+        ctx_run: Callable,
+        gen: "Generator[_Yieldable, Any, _T]",
+        result_future: "Future[_T]",
+        first_yielded: _Yieldable,
+    ) -> None:
+        self.ctx_run = ctx_run
+        self.gen = gen
+        self.result_future = result_future
+        self.future = _null_future  # type: Union[None, Future]
+        self.running = False
+        self.finished = False
+        self.io_loop = IOLoop.current()
+        if self.ctx_run(self.handle_yield, first_yielded):
+            gen = result_future = first_yielded = None  # type: ignore
+            self.ctx_run(self.run)
+
+    def run(self) -> None:
+        """Starts or resumes the generator, running until it reaches a
+        yield point that is not ready.
+        """
+        if self.running or self.finished:
+            return
+        try:
+            self.running = True
+            while True:
+                future = self.future
+                if future is None:
+                    raise Exception("No pending future")
+                if not future.done():
+                    return
+                self.future = None
+                try:
+                    try:
+                        value = future.result()
+                    except Exception as e:
+                        # Save the exception for later. It's important that
+                        # gen.throw() not be called inside this try/except block
+                        # because that makes sys.exc_info behave unexpectedly.
+                        exc: Optional[Exception] = e
+                    else:
+                        exc = None
+                    finally:
+                        future = None
+
+                    if exc is not None:
+                        try:
+                            yielded = self.gen.throw(exc)
+                        finally:
+                            # Break up a circular reference for faster GC on
+                            # CPython.
+                            del exc
+                    else:
+                        yielded = self.gen.send(value)
+
+                except (StopIteration, Return) as e:
+                    self.finished = True
+                    self.future = _null_future
+                    future_set_result_unless_cancelled(
+                        self.result_future, _value_from_stopiteration(e)
+                    )
+                    self.result_future = None  # type: ignore
+                    return
+                except Exception:
+                    self.finished = True
+                    self.future = _null_future
+                    future_set_exc_info(self.result_future, sys.exc_info())
+                    self.result_future = None  # type: ignore
+                    return
+                if not self.handle_yield(yielded):
+                    return
+                yielded = None
+        finally:
+            self.running = False
+
+    def handle_yield(self, yielded: _Yieldable) -> bool:
+        try:
+            self.future = convert_yielded(yielded)
+        except BadYieldError:
+            self.future = Future()
+            future_set_exc_info(self.future, sys.exc_info())
+
+        if self.future is moment:
+            self.io_loop.add_callback(self.ctx_run, self.run)
+            return False
+        elif self.future is None:
+            raise Exception("no pending future")
+        elif not self.future.done():
+
+            def inner(f: Any) -> None:
+                # Break a reference cycle to speed GC.
+                f = None  # noqa: F841
+                self.ctx_run(self.run)
+
+            self.io_loop.add_future(self.future, inner)
+            return False
+        return True
+
+    def handle_exception(
+        self, typ: Type[Exception], value: Exception, tb: types.TracebackType
+    ) -> bool:
+        if not self.running and not self.finished:
+            self.future = Future()
+            future_set_exc_info(self.future, (typ, value, tb))
+            self.ctx_run(self.run)
+            return True
+        else:
+            return False
+
+
+# Convert Awaitables into Futures.
+try:
+    _wrap_awaitable = asyncio.ensure_future
+except AttributeError:
+    # asyncio.ensure_future was introduced in Python 3.4.4, but
+    # Debian jessie still ships with 3.4.2 so try the old name.
+    _wrap_awaitable = getattr(asyncio, "async")
+
+
+def convert_yielded(yielded: _Yieldable) -> Future:
+    """Convert a yielded object into a `.Future`.
+
+    The default implementation accepts lists, dictionaries, and
+    Futures. This has the side effect of starting any coroutines that
+    did not start themselves, similar to `asyncio.ensure_future`.
+
+    If the `~functools.singledispatch` library is available, this function
+    may be extended to support additional types. For example::
+
+        @convert_yielded.register(asyncio.Future)
+        def _(asyncio_future):
+            return tornado.platform.asyncio.to_tornado_future(asyncio_future)
+
+    .. versionadded:: 4.1
+
+    """
+    if yielded is None or yielded is moment:
+        return moment
+    elif yielded is _null_future:
+        return _null_future
+    elif isinstance(yielded, (list, dict)):
+        return multi(yielded)  # type: ignore
+    elif is_future(yielded):
+        return typing.cast(Future, yielded)
+    elif isawaitable(yielded):
+        return _wrap_awaitable(yielded)  # type: ignore
+    else:
+        raise BadYieldError("yielded unknown object %r" % (yielded,))
+
+
+convert_yielded = singledispatch(convert_yielded)
diff --git a/venv/lib/python3.9/site-packages/tornado/http1connection.py b/venv/lib/python3.9/site-packages/tornado/http1connection.py
new file mode 100644
index 00000000..5ca91688
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/http1connection.py
@@ -0,0 +1,844 @@
+#
+# Copyright 2014 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Client and server implementations of HTTP/1.x.
+
+.. versionadded:: 4.0
+"""
+
+import asyncio
+import logging
+import re
+import types
+
+from tornado.concurrent import (
+    Future,
+    future_add_done_callback,
+    future_set_result_unless_cancelled,
+)
+from tornado.escape import native_str, utf8
+from tornado import gen
+from tornado import httputil
+from tornado import iostream
+from tornado.log import gen_log, app_log
+from tornado.util import GzipDecompressor
+
+
+from typing import cast, Optional, Type, Awaitable, Callable, Union, Tuple
+
+
+class _QuietException(Exception):
+    def __init__(self) -> None:
+        pass
+
+
+class _ExceptionLoggingContext(object):
+    """Used with the ``with`` statement when calling delegate methods to
+    log any exceptions with the given logger.  Any exceptions caught are
+    converted to _QuietException
+    """
+
+    def __init__(self, logger: logging.Logger) -> None:
+        self.logger = logger
+
+    def __enter__(self) -> None:
+        pass
+
+    def __exit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: types.TracebackType,
+    ) -> None:
+        if value is not None:
+            assert typ is not None
+            self.logger.error("Uncaught exception", exc_info=(typ, value, tb))
+            raise _QuietException
+
+
+class HTTP1ConnectionParameters(object):
+    """Parameters for `.HTTP1Connection` and `.HTTP1ServerConnection`."""
+
+    def __init__(
+        self,
+        no_keep_alive: bool = False,
+        chunk_size: Optional[int] = None,
+        max_header_size: Optional[int] = None,
+        header_timeout: Optional[float] = None,
+        max_body_size: Optional[int] = None,
+        body_timeout: Optional[float] = None,
+        decompress: bool = False,
+    ) -> None:
+        """
+        :arg bool no_keep_alive: If true, always close the connection after
+            one request.
+        :arg int chunk_size: how much data to read into memory at once
+        :arg int max_header_size:  maximum amount of data for HTTP headers
+        :arg float header_timeout: how long to wait for all headers (seconds)
+        :arg int max_body_size: maximum amount of data for body
+        :arg float body_timeout: how long to wait while reading body (seconds)
+        :arg bool decompress: if true, decode incoming
+            ``Content-Encoding: gzip``
+        """
+        self.no_keep_alive = no_keep_alive
+        self.chunk_size = chunk_size or 65536
+        self.max_header_size = max_header_size or 65536
+        self.header_timeout = header_timeout
+        self.max_body_size = max_body_size
+        self.body_timeout = body_timeout
+        self.decompress = decompress
+
+
+class HTTP1Connection(httputil.HTTPConnection):
+    """Implements the HTTP/1.x protocol.
+
+    This class can be on its own for clients, or via `HTTP1ServerConnection`
+    for servers.
+    """
+
+    def __init__(
+        self,
+        stream: iostream.IOStream,
+        is_client: bool,
+        params: Optional[HTTP1ConnectionParameters] = None,
+        context: Optional[object] = None,
+    ) -> None:
+        """
+        :arg stream: an `.IOStream`
+        :arg bool is_client: client or server
+        :arg params: a `.HTTP1ConnectionParameters` instance or ``None``
+        :arg context: an opaque application-defined object that can be accessed
+            as ``connection.context``.
+        """
+        self.is_client = is_client
+        self.stream = stream
+        if params is None:
+            params = HTTP1ConnectionParameters()
+        self.params = params
+        self.context = context
+        self.no_keep_alive = params.no_keep_alive
+        # The body limits can be altered by the delegate, so save them
+        # here instead of just referencing self.params later.
+        self._max_body_size = (
+            self.params.max_body_size
+            if self.params.max_body_size is not None
+            else self.stream.max_buffer_size
+        )
+        self._body_timeout = self.params.body_timeout
+        # _write_finished is set to True when finish() has been called,
+        # i.e. there will be no more data sent.  Data may still be in the
+        # stream's write buffer.
+        self._write_finished = False
+        # True when we have read the entire incoming body.
+        self._read_finished = False
+        # _finish_future resolves when all data has been written and flushed
+        # to the IOStream.
+        self._finish_future = Future()  # type: Future[None]
+        # If true, the connection should be closed after this request
+        # (after the response has been written in the server side,
+        # and after it has been read in the client)
+        self._disconnect_on_finish = False
+        self._clear_callbacks()
+        # Save the start lines after we read or write them; they
+        # affect later processing (e.g. 304 responses and HEAD methods
+        # have content-length but no bodies)
+        self._request_start_line = None  # type: Optional[httputil.RequestStartLine]
+        self._response_start_line = None  # type: Optional[httputil.ResponseStartLine]
+        self._request_headers = None  # type: Optional[httputil.HTTPHeaders]
+        # True if we are writing output with chunked encoding.
+        self._chunking_output = False
+        # While reading a body with a content-length, this is the
+        # amount left to read.
+        self._expected_content_remaining = None  # type: Optional[int]
+        # A Future for our outgoing writes, returned by IOStream.write.
+        self._pending_write = None  # type: Optional[Future[None]]
+
+    def read_response(self, delegate: httputil.HTTPMessageDelegate) -> Awaitable[bool]:
+        """Read a single HTTP response.
+
+        Typical client-mode usage is to write a request using `write_headers`,
+        `write`, and `finish`, and then call ``read_response``.
+
+        :arg delegate: a `.HTTPMessageDelegate`
+
+        Returns a `.Future` that resolves to a bool after the full response has
+        been read. The result is true if the stream is still open.
+        """
+        if self.params.decompress:
+            delegate = _GzipMessageDelegate(delegate, self.params.chunk_size)
+        return self._read_message(delegate)
+
+    async def _read_message(self, delegate: httputil.HTTPMessageDelegate) -> bool:
+        need_delegate_close = False
+        try:
+            header_future = self.stream.read_until_regex(
+                b"\r?\n\r?\n", max_bytes=self.params.max_header_size
+            )
+            if self.params.header_timeout is None:
+                header_data = await header_future
+            else:
+                try:
+                    header_data = await gen.with_timeout(
+                        self.stream.io_loop.time() + self.params.header_timeout,
+                        header_future,
+                        quiet_exceptions=iostream.StreamClosedError,
+                    )
+                except gen.TimeoutError:
+                    self.close()
+                    return False
+            start_line_str, headers = self._parse_headers(header_data)
+            if self.is_client:
+                resp_start_line = httputil.parse_response_start_line(start_line_str)
+                self._response_start_line = resp_start_line
+                start_line = (
+                    resp_start_line
+                )  # type: Union[httputil.RequestStartLine, httputil.ResponseStartLine]
+                # TODO: this will need to change to support client-side keepalive
+                self._disconnect_on_finish = False
+            else:
+                req_start_line = httputil.parse_request_start_line(start_line_str)
+                self._request_start_line = req_start_line
+                self._request_headers = headers
+                start_line = req_start_line
+                self._disconnect_on_finish = not self._can_keep_alive(
+                    req_start_line, headers
+                )
+            need_delegate_close = True
+            with _ExceptionLoggingContext(app_log):
+                header_recv_future = delegate.headers_received(start_line, headers)
+                if header_recv_future is not None:
+                    await header_recv_future
+            if self.stream is None:
+                # We've been detached.
+                need_delegate_close = False
+                return False
+            skip_body = False
+            if self.is_client:
+                assert isinstance(start_line, httputil.ResponseStartLine)
+                if (
+                    self._request_start_line is not None
+                    and self._request_start_line.method == "HEAD"
+                ):
+                    skip_body = True
+                code = start_line.code
+                if code == 304:
+                    # 304 responses may include the content-length header
+                    # but do not actually have a body.
+                    # http://tools.ietf.org/html/rfc7230#section-3.3
+                    skip_body = True
+                if 100 <= code < 200:
+                    # 1xx responses should never indicate the presence of
+                    # a body.
+                    if "Content-Length" in headers or "Transfer-Encoding" in headers:
+                        raise httputil.HTTPInputError(
+                            "Response code %d cannot have body" % code
+                        )
+                    # TODO: client delegates will get headers_received twice
+                    # in the case of a 100-continue.  Document or change?
+                    await self._read_message(delegate)
+            else:
+                if headers.get("Expect") == "100-continue" and not self._write_finished:
+                    self.stream.write(b"HTTP/1.1 100 (Continue)\r\n\r\n")
+            if not skip_body:
+                body_future = self._read_body(
+                    resp_start_line.code if self.is_client else 0, headers, delegate
+                )
+                if body_future is not None:
+                    if self._body_timeout is None:
+                        await body_future
+                    else:
+                        try:
+                            await gen.with_timeout(
+                                self.stream.io_loop.time() + self._body_timeout,
+                                body_future,
+                                quiet_exceptions=iostream.StreamClosedError,
+                            )
+                        except gen.TimeoutError:
+                            gen_log.info("Timeout reading body from %s", self.context)
+                            self.stream.close()
+                            return False
+            self._read_finished = True
+            if not self._write_finished or self.is_client:
+                need_delegate_close = False
+                with _ExceptionLoggingContext(app_log):
+                    delegate.finish()
+            # If we're waiting for the application to produce an asynchronous
+            # response, and we're not detached, register a close callback
+            # on the stream (we didn't need one while we were reading)
+            if (
+                not self._finish_future.done()
+                and self.stream is not None
+                and not self.stream.closed()
+            ):
+                self.stream.set_close_callback(self._on_connection_close)
+                await self._finish_future
+            if self.is_client and self._disconnect_on_finish:
+                self.close()
+            if self.stream is None:
+                return False
+        except httputil.HTTPInputError as e:
+            gen_log.info("Malformed HTTP message from %s: %s", self.context, e)
+            if not self.is_client:
+                await self.stream.write(b"HTTP/1.1 400 Bad Request\r\n\r\n")
+            self.close()
+            return False
+        finally:
+            if need_delegate_close:
+                with _ExceptionLoggingContext(app_log):
+                    delegate.on_connection_close()
+            header_future = None  # type: ignore
+            self._clear_callbacks()
+        return True
+
+    def _clear_callbacks(self) -> None:
+        """Clears the callback attributes.
+
+        This allows the request handler to be garbage collected more
+        quickly in CPython by breaking up reference cycles.
+        """
+        self._write_callback = None
+        self._write_future = None  # type: Optional[Future[None]]
+        self._close_callback = None  # type: Optional[Callable[[], None]]
+        if self.stream is not None:
+            self.stream.set_close_callback(None)
+
+    def set_close_callback(self, callback: Optional[Callable[[], None]]) -> None:
+        """Sets a callback that will be run when the connection is closed.
+
+        Note that this callback is slightly different from
+        `.HTTPMessageDelegate.on_connection_close`: The
+        `.HTTPMessageDelegate` method is called when the connection is
+        closed while receiving a message. This callback is used when
+        there is not an active delegate (for example, on the server
+        side this callback is used if the client closes the connection
+        after sending its request but before receiving all the
+        response.
+        """
+        self._close_callback = callback
+
+    def _on_connection_close(self) -> None:
+        # Note that this callback is only registered on the IOStream
+        # when we have finished reading the request and are waiting for
+        # the application to produce its response.
+        if self._close_callback is not None:
+            callback = self._close_callback
+            self._close_callback = None
+            callback()
+        if not self._finish_future.done():
+            future_set_result_unless_cancelled(self._finish_future, None)
+        self._clear_callbacks()
+
+    def close(self) -> None:
+        if self.stream is not None:
+            self.stream.close()
+        self._clear_callbacks()
+        if not self._finish_future.done():
+            future_set_result_unless_cancelled(self._finish_future, None)
+
+    def detach(self) -> iostream.IOStream:
+        """Take control of the underlying stream.
+
+        Returns the underlying `.IOStream` object and stops all further
+        HTTP processing.  May only be called during
+        `.HTTPMessageDelegate.headers_received`.  Intended for implementing
+        protocols like websockets that tunnel over an HTTP handshake.
+        """
+        self._clear_callbacks()
+        stream = self.stream
+        self.stream = None  # type: ignore
+        if not self._finish_future.done():
+            future_set_result_unless_cancelled(self._finish_future, None)
+        return stream
+
+    def set_body_timeout(self, timeout: float) -> None:
+        """Sets the body timeout for a single request.
+
+        Overrides the value from `.HTTP1ConnectionParameters`.
+        """
+        self._body_timeout = timeout
+
+    def set_max_body_size(self, max_body_size: int) -> None:
+        """Sets the body size limit for a single request.
+
+        Overrides the value from `.HTTP1ConnectionParameters`.
+        """
+        self._max_body_size = max_body_size
+
+    def write_headers(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+        chunk: Optional[bytes] = None,
+    ) -> "Future[None]":
+        """Implements `.HTTPConnection.write_headers`."""
+        lines = []
+        if self.is_client:
+            assert isinstance(start_line, httputil.RequestStartLine)
+            self._request_start_line = start_line
+            lines.append(utf8("%s %s HTTP/1.1" % (start_line[0], start_line[1])))
+            # Client requests with a non-empty body must have either a
+            # Content-Length or a Transfer-Encoding.
+            self._chunking_output = (
+                start_line.method in ("POST", "PUT", "PATCH")
+                and "Content-Length" not in headers
+                and (
+                    "Transfer-Encoding" not in headers
+                    or headers["Transfer-Encoding"] == "chunked"
+                )
+            )
+        else:
+            assert isinstance(start_line, httputil.ResponseStartLine)
+            assert self._request_start_line is not None
+            assert self._request_headers is not None
+            self._response_start_line = start_line
+            lines.append(utf8("HTTP/1.1 %d %s" % (start_line[1], start_line[2])))
+            self._chunking_output = (
+                # TODO: should this use
+                # self._request_start_line.version or
+                # start_line.version?
+                self._request_start_line.version == "HTTP/1.1"
+                # Omit payload header field for HEAD request.
+                and self._request_start_line.method != "HEAD"
+                # 1xx, 204 and 304 responses have no body (not even a zero-length
+                # body), and so should not have either Content-Length or
+                # Transfer-Encoding headers.
+                and start_line.code not in (204, 304)
+                and (start_line.code < 100 or start_line.code >= 200)
+                # No need to chunk the output if a Content-Length is specified.
+                and "Content-Length" not in headers
+                # Applications are discouraged from touching Transfer-Encoding,
+                # but if they do, leave it alone.
+                and "Transfer-Encoding" not in headers
+            )
+            # If connection to a 1.1 client will be closed, inform client
+            if (
+                self._request_start_line.version == "HTTP/1.1"
+                and self._disconnect_on_finish
+            ):
+                headers["Connection"] = "close"
+            # If a 1.0 client asked for keep-alive, add the header.
+            if (
+                self._request_start_line.version == "HTTP/1.0"
+                and self._request_headers.get("Connection", "").lower() == "keep-alive"
+            ):
+                headers["Connection"] = "Keep-Alive"
+        if self._chunking_output:
+            headers["Transfer-Encoding"] = "chunked"
+        if not self.is_client and (
+            self._request_start_line.method == "HEAD"
+            or cast(httputil.ResponseStartLine, start_line).code == 304
+        ):
+            self._expected_content_remaining = 0
+        elif "Content-Length" in headers:
+            self._expected_content_remaining = int(headers["Content-Length"])
+        else:
+            self._expected_content_remaining = None
+        # TODO: headers are supposed to be of type str, but we still have some
+        # cases that let bytes slip through. Remove these native_str calls when those
+        # are fixed.
+        header_lines = (
+            native_str(n) + ": " + native_str(v) for n, v in headers.get_all()
+        )
+        lines.extend(line.encode("latin1") for line in header_lines)
+        for line in lines:
+            if b"\n" in line:
+                raise ValueError("Newline in header: " + repr(line))
+        future = None
+        if self.stream.closed():
+            future = self._write_future = Future()
+            future.set_exception(iostream.StreamClosedError())
+            future.exception()
+        else:
+            future = self._write_future = Future()
+            data = b"\r\n".join(lines) + b"\r\n\r\n"
+            if chunk:
+                data += self._format_chunk(chunk)
+            self._pending_write = self.stream.write(data)
+            future_add_done_callback(self._pending_write, self._on_write_complete)
+        return future
+
+    def _format_chunk(self, chunk: bytes) -> bytes:
+        if self._expected_content_remaining is not None:
+            self._expected_content_remaining -= len(chunk)
+            if self._expected_content_remaining < 0:
+                # Close the stream now to stop further framing errors.
+                self.stream.close()
+                raise httputil.HTTPOutputError(
+                    "Tried to write more data than Content-Length"
+                )
+        if self._chunking_output and chunk:
+            # Don't write out empty chunks because that means END-OF-STREAM
+            # with chunked encoding
+            return utf8("%x" % len(chunk)) + b"\r\n" + chunk + b"\r\n"
+        else:
+            return chunk
+
+    def write(self, chunk: bytes) -> "Future[None]":
+        """Implements `.HTTPConnection.write`.
+
+        For backwards compatibility it is allowed but deprecated to
+        skip `write_headers` and instead call `write()` with a
+        pre-encoded header block.
+        """
+        future = None
+        if self.stream.closed():
+            future = self._write_future = Future()
+            self._write_future.set_exception(iostream.StreamClosedError())
+            self._write_future.exception()
+        else:
+            future = self._write_future = Future()
+            self._pending_write = self.stream.write(self._format_chunk(chunk))
+            future_add_done_callback(self._pending_write, self._on_write_complete)
+        return future
+
+    def finish(self) -> None:
+        """Implements `.HTTPConnection.finish`."""
+        if (
+            self._expected_content_remaining is not None
+            and self._expected_content_remaining != 0
+            and not self.stream.closed()
+        ):
+            self.stream.close()
+            raise httputil.HTTPOutputError(
+                "Tried to write %d bytes less than Content-Length"
+                % self._expected_content_remaining
+            )
+        if self._chunking_output:
+            if not self.stream.closed():
+                self._pending_write = self.stream.write(b"0\r\n\r\n")
+                self._pending_write.add_done_callback(self._on_write_complete)
+        self._write_finished = True
+        # If the app finished the request while we're still reading,
+        # divert any remaining data away from the delegate and
+        # close the connection when we're done sending our response.
+        # Closing the connection is the only way to avoid reading the
+        # whole input body.
+        if not self._read_finished:
+            self._disconnect_on_finish = True
+        # No more data is coming, so instruct TCP to send any remaining
+        # data immediately instead of waiting for a full packet or ack.
+        self.stream.set_nodelay(True)
+        if self._pending_write is None:
+            self._finish_request(None)
+        else:
+            future_add_done_callback(self._pending_write, self._finish_request)
+
+    def _on_write_complete(self, future: "Future[None]") -> None:
+        exc = future.exception()
+        if exc is not None and not isinstance(exc, iostream.StreamClosedError):
+            future.result()
+        if self._write_callback is not None:
+            callback = self._write_callback
+            self._write_callback = None
+            self.stream.io_loop.add_callback(callback)
+        if self._write_future is not None:
+            future = self._write_future
+            self._write_future = None
+            future_set_result_unless_cancelled(future, None)
+
+    def _can_keep_alive(
+        self, start_line: httputil.RequestStartLine, headers: httputil.HTTPHeaders
+    ) -> bool:
+        if self.params.no_keep_alive:
+            return False
+        connection_header = headers.get("Connection")
+        if connection_header is not None:
+            connection_header = connection_header.lower()
+        if start_line.version == "HTTP/1.1":
+            return connection_header != "close"
+        elif (
+            "Content-Length" in headers
+            or headers.get("Transfer-Encoding", "").lower() == "chunked"
+            or getattr(start_line, "method", None) in ("HEAD", "GET")
+        ):
+            # start_line may be a request or response start line; only
+            # the former has a method attribute.
+            return connection_header == "keep-alive"
+        return False
+
+    def _finish_request(self, future: "Optional[Future[None]]") -> None:
+        self._clear_callbacks()
+        if not self.is_client and self._disconnect_on_finish:
+            self.close()
+            return
+        # Turn Nagle's algorithm back on, leaving the stream in its
+        # default state for the next request.
+        self.stream.set_nodelay(False)
+        if not self._finish_future.done():
+            future_set_result_unless_cancelled(self._finish_future, None)
+
+    def _parse_headers(self, data: bytes) -> Tuple[str, httputil.HTTPHeaders]:
+        # The lstrip removes newlines that some implementations sometimes
+        # insert between messages of a reused connection.  Per RFC 7230,
+        # we SHOULD ignore at least one empty line before the request.
+        # http://tools.ietf.org/html/rfc7230#section-3.5
+        data_str = native_str(data.decode("latin1")).lstrip("\r\n")
+        # RFC 7230 section allows for both CRLF and bare LF.
+        eol = data_str.find("\n")
+        start_line = data_str[:eol].rstrip("\r")
+        headers = httputil.HTTPHeaders.parse(data_str[eol:])
+        return start_line, headers
+
+    def _read_body(
+        self,
+        code: int,
+        headers: httputil.HTTPHeaders,
+        delegate: httputil.HTTPMessageDelegate,
+    ) -> Optional[Awaitable[None]]:
+        if "Content-Length" in headers:
+            if "Transfer-Encoding" in headers:
+                # Response cannot contain both Content-Length and
+                # Transfer-Encoding headers.
+                # http://tools.ietf.org/html/rfc7230#section-3.3.3
+                raise httputil.HTTPInputError(
+                    "Response with both Transfer-Encoding and Content-Length"
+                )
+            if "," in headers["Content-Length"]:
+                # Proxies sometimes cause Content-Length headers to get
+                # duplicated.  If all the values are identical then we can
+                # use them but if they differ it's an error.
+                pieces = re.split(r",\s*", headers["Content-Length"])
+                if any(i != pieces[0] for i in pieces):
+                    raise httputil.HTTPInputError(
+                        "Multiple unequal Content-Lengths: %r"
+                        % headers["Content-Length"]
+                    )
+                headers["Content-Length"] = pieces[0]
+
+            try:
+                content_length = int(headers["Content-Length"])  # type: Optional[int]
+            except ValueError:
+                # Handles non-integer Content-Length value.
+                raise httputil.HTTPInputError(
+                    "Only integer Content-Length is allowed: %s"
+                    % headers["Content-Length"]
+                )
+
+            if cast(int, content_length) > self._max_body_size:
+                raise httputil.HTTPInputError("Content-Length too long")
+        else:
+            content_length = None
+
+        if code == 204:
+            # This response code is not allowed to have a non-empty body,
+            # and has an implicit length of zero instead of read-until-close.
+            # http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
+            if "Transfer-Encoding" in headers or content_length not in (None, 0):
+                raise httputil.HTTPInputError(
+                    "Response with code %d should not have body" % code
+                )
+            content_length = 0
+
+        if content_length is not None:
+            return self._read_fixed_body(content_length, delegate)
+        if headers.get("Transfer-Encoding", "").lower() == "chunked":
+            return self._read_chunked_body(delegate)
+        if self.is_client:
+            return self._read_body_until_close(delegate)
+        return None
+
+    async def _read_fixed_body(
+        self, content_length: int, delegate: httputil.HTTPMessageDelegate
+    ) -> None:
+        while content_length > 0:
+            body = await self.stream.read_bytes(
+                min(self.params.chunk_size, content_length), partial=True
+            )
+            content_length -= len(body)
+            if not self._write_finished or self.is_client:
+                with _ExceptionLoggingContext(app_log):
+                    ret = delegate.data_received(body)
+                    if ret is not None:
+                        await ret
+
+    async def _read_chunked_body(self, delegate: httputil.HTTPMessageDelegate) -> None:
+        # TODO: "chunk extensions" http://tools.ietf.org/html/rfc2616#section-3.6.1
+        total_size = 0
+        while True:
+            chunk_len_str = await self.stream.read_until(b"\r\n", max_bytes=64)
+            chunk_len = int(chunk_len_str.strip(), 16)
+            if chunk_len == 0:
+                crlf = await self.stream.read_bytes(2)
+                if crlf != b"\r\n":
+                    raise httputil.HTTPInputError(
+                        "improperly terminated chunked request"
+                    )
+                return
+            total_size += chunk_len
+            if total_size > self._max_body_size:
+                raise httputil.HTTPInputError("chunked body too large")
+            bytes_to_read = chunk_len
+            while bytes_to_read:
+                chunk = await self.stream.read_bytes(
+                    min(bytes_to_read, self.params.chunk_size), partial=True
+                )
+                bytes_to_read -= len(chunk)
+                if not self._write_finished or self.is_client:
+                    with _ExceptionLoggingContext(app_log):
+                        ret = delegate.data_received(chunk)
+                        if ret is not None:
+                            await ret
+            # chunk ends with \r\n
+            crlf = await self.stream.read_bytes(2)
+            assert crlf == b"\r\n"
+
+    async def _read_body_until_close(
+        self, delegate: httputil.HTTPMessageDelegate
+    ) -> None:
+        body = await self.stream.read_until_close()
+        if not self._write_finished or self.is_client:
+            with _ExceptionLoggingContext(app_log):
+                ret = delegate.data_received(body)
+                if ret is not None:
+                    await ret
+
+
+class _GzipMessageDelegate(httputil.HTTPMessageDelegate):
+    """Wraps an `HTTPMessageDelegate` to decode ``Content-Encoding: gzip``."""
+
+    def __init__(self, delegate: httputil.HTTPMessageDelegate, chunk_size: int) -> None:
+        self._delegate = delegate
+        self._chunk_size = chunk_size
+        self._decompressor = None  # type: Optional[GzipDecompressor]
+
+    def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        if headers.get("Content-Encoding", "").lower() == "gzip":
+            self._decompressor = GzipDecompressor()
+            # Downstream delegates will only see uncompressed data,
+            # so rename the content-encoding header.
+            # (but note that curl_httpclient doesn't do this).
+            headers.add("X-Consumed-Content-Encoding", headers["Content-Encoding"])
+            del headers["Content-Encoding"]
+        return self._delegate.headers_received(start_line, headers)
+
+    async def data_received(self, chunk: bytes) -> None:
+        if self._decompressor:
+            compressed_data = chunk
+            while compressed_data:
+                decompressed = self._decompressor.decompress(
+                    compressed_data, self._chunk_size
+                )
+                if decompressed:
+                    ret = self._delegate.data_received(decompressed)
+                    if ret is not None:
+                        await ret
+                compressed_data = self._decompressor.unconsumed_tail
+                if compressed_data and not decompressed:
+                    raise httputil.HTTPInputError(
+                        "encountered unconsumed gzip data without making progress"
+                    )
+        else:
+            ret = self._delegate.data_received(chunk)
+            if ret is not None:
+                await ret
+
+    def finish(self) -> None:
+        if self._decompressor is not None:
+            tail = self._decompressor.flush()
+            if tail:
+                # The tail should always be empty: decompress returned
+                # all that it can in data_received and the only
+                # purpose of the flush call is to detect errors such
+                # as truncated input. If we did legitimately get a new
+                # chunk at this point we'd need to change the
+                # interface to make finish() a coroutine.
+                raise ValueError(
+                    "decompressor.flush returned data; possible truncated input"
+                )
+        return self._delegate.finish()
+
+    def on_connection_close(self) -> None:
+        return self._delegate.on_connection_close()
+
+
+class HTTP1ServerConnection(object):
+    """An HTTP/1.x server."""
+
+    def __init__(
+        self,
+        stream: iostream.IOStream,
+        params: Optional[HTTP1ConnectionParameters] = None,
+        context: Optional[object] = None,
+    ) -> None:
+        """
+        :arg stream: an `.IOStream`
+        :arg params: a `.HTTP1ConnectionParameters` or None
+        :arg context: an opaque application-defined object that is accessible
+            as ``connection.context``
+        """
+        self.stream = stream
+        if params is None:
+            params = HTTP1ConnectionParameters()
+        self.params = params
+        self.context = context
+        self._serving_future = None  # type: Optional[Future[None]]
+
+    async def close(self) -> None:
+        """Closes the connection.
+
+        Returns a `.Future` that resolves after the serving loop has exited.
+        """
+        self.stream.close()
+        # Block until the serving loop is done, but ignore any exceptions
+        # (start_serving is already responsible for logging them).
+        assert self._serving_future is not None
+        try:
+            await self._serving_future
+        except Exception:
+            pass
+
+    def start_serving(self, delegate: httputil.HTTPServerConnectionDelegate) -> None:
+        """Starts serving requests on this connection.
+
+        :arg delegate: a `.HTTPServerConnectionDelegate`
+        """
+        assert isinstance(delegate, httputil.HTTPServerConnectionDelegate)
+        fut = gen.convert_yielded(self._server_request_loop(delegate))
+        self._serving_future = fut
+        # Register the future on the IOLoop so its errors get logged.
+        self.stream.io_loop.add_future(fut, lambda f: f.result())
+
+    async def _server_request_loop(
+        self, delegate: httputil.HTTPServerConnectionDelegate
+    ) -> None:
+        try:
+            while True:
+                conn = HTTP1Connection(self.stream, False, self.params, self.context)
+                request_delegate = delegate.start_request(self, conn)
+                try:
+                    ret = await conn.read_response(request_delegate)
+                except (
+                    iostream.StreamClosedError,
+                    iostream.UnsatisfiableReadError,
+                    asyncio.CancelledError,
+                ):
+                    return
+                except _QuietException:
+                    # This exception was already logged.
+                    conn.close()
+                    return
+                except Exception:
+                    gen_log.error("Uncaught exception", exc_info=True)
+                    conn.close()
+                    return
+                if not ret:
+                    return
+                await asyncio.sleep(0)
+        finally:
+            delegate.on_close(self)
diff --git a/venv/lib/python3.9/site-packages/tornado/httpclient.py b/venv/lib/python3.9/site-packages/tornado/httpclient.py
new file mode 100644
index 00000000..3011c371
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/httpclient.py
@@ -0,0 +1,790 @@
+"""Blocking and non-blocking HTTP client interfaces.
+
+This module defines a common interface shared by two implementations,
+``simple_httpclient`` and ``curl_httpclient``.  Applications may either
+instantiate their chosen implementation class directly or use the
+`AsyncHTTPClient` class from this module, which selects an implementation
+that can be overridden with the `AsyncHTTPClient.configure` method.
+
+The default implementation is ``simple_httpclient``, and this is expected
+to be suitable for most users' needs.  However, some applications may wish
+to switch to ``curl_httpclient`` for reasons such as the following:
+
+* ``curl_httpclient`` has some features not found in ``simple_httpclient``,
+  including support for HTTP proxies and the ability to use a specified
+  network interface.
+
+* ``curl_httpclient`` is more likely to be compatible with sites that are
+  not-quite-compliant with the HTTP spec, or sites that use little-exercised
+  features of HTTP.
+
+* ``curl_httpclient`` is faster.
+
+Note that if you are using ``curl_httpclient``, it is highly
+recommended that you use a recent version of ``libcurl`` and
+``pycurl``.  Currently the minimum supported version of libcurl is
+7.22.0, and the minimum version of pycurl is 7.18.2.  It is highly
+recommended that your ``libcurl`` installation is built with
+asynchronous DNS resolver (threaded or c-ares), otherwise you may
+encounter various problems with request timeouts (for more
+information, see
+http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTCONNECTTIMEOUTMS
+and comments in curl_httpclient.py).
+
+To select ``curl_httpclient``, call `AsyncHTTPClient.configure` at startup::
+
+    AsyncHTTPClient.configure("tornado.curl_httpclient.CurlAsyncHTTPClient")
+"""
+
+import datetime
+import functools
+from io import BytesIO
+import ssl
+import time
+import weakref
+
+from tornado.concurrent import (
+    Future,
+    future_set_result_unless_cancelled,
+    future_set_exception_unless_cancelled,
+)
+from tornado.escape import utf8, native_str
+from tornado import gen, httputil
+from tornado.ioloop import IOLoop
+from tornado.util import Configurable
+
+from typing import Type, Any, Union, Dict, Callable, Optional, cast
+
+
+class HTTPClient(object):
+    """A blocking HTTP client.
+
+    This interface is provided to make it easier to share code between
+    synchronous and asynchronous applications. Applications that are
+    running an `.IOLoop` must use `AsyncHTTPClient` instead.
+
+    Typical usage looks like this::
+
+        http_client = httpclient.HTTPClient()
+        try:
+            response = http_client.fetch("http://www.google.com/")
+            print(response.body)
+        except httpclient.HTTPError as e:
+            # HTTPError is raised for non-200 responses; the response
+            # can be found in e.response.
+            print("Error: " + str(e))
+        except Exception as e:
+            # Other errors are possible, such as IOError.
+            print("Error: " + str(e))
+        http_client.close()
+
+    .. versionchanged:: 5.0
+
+       Due to limitations in `asyncio`, it is no longer possible to
+       use the synchronous ``HTTPClient`` while an `.IOLoop` is running.
+       Use `AsyncHTTPClient` instead.
+
+    """
+
+    def __init__(
+        self,
+        async_client_class: "Optional[Type[AsyncHTTPClient]]" = None,
+        **kwargs: Any
+    ) -> None:
+        # Initialize self._closed at the beginning of the constructor
+        # so that an exception raised here doesn't lead to confusing
+        # failures in __del__.
+        self._closed = True
+        self._io_loop = IOLoop(make_current=False)
+        if async_client_class is None:
+            async_client_class = AsyncHTTPClient
+
+        # Create the client while our IOLoop is "current", without
+        # clobbering the thread's real current IOLoop (if any).
+        async def make_client() -> "AsyncHTTPClient":
+            await gen.sleep(0)
+            assert async_client_class is not None
+            return async_client_class(**kwargs)
+
+        self._async_client = self._io_loop.run_sync(make_client)
+        self._closed = False
+
+    def __del__(self) -> None:
+        self.close()
+
+    def close(self) -> None:
+        """Closes the HTTPClient, freeing any resources used."""
+        if not self._closed:
+            self._async_client.close()
+            self._io_loop.close()
+            self._closed = True
+
+    def fetch(
+        self, request: Union["HTTPRequest", str], **kwargs: Any
+    ) -> "HTTPResponse":
+        """Executes a request, returning an `HTTPResponse`.
+
+        The request may be either a string URL or an `HTTPRequest` object.
+        If it is a string, we construct an `HTTPRequest` using any additional
+        kwargs: ``HTTPRequest(request, **kwargs)``
+
+        If an error occurs during the fetch, we raise an `HTTPError` unless
+        the ``raise_error`` keyword argument is set to False.
+        """
+        response = self._io_loop.run_sync(
+            functools.partial(self._async_client.fetch, request, **kwargs)
+        )
+        return response
+
+
+class AsyncHTTPClient(Configurable):
+    """An non-blocking HTTP client.
+
+    Example usage::
+
+        async def f():
+            http_client = AsyncHTTPClient()
+            try:
+                response = await http_client.fetch("http://www.google.com")
+            except Exception as e:
+                print("Error: %s" % e)
+            else:
+                print(response.body)
+
+    The constructor for this class is magic in several respects: It
+    actually creates an instance of an implementation-specific
+    subclass, and instances are reused as a kind of pseudo-singleton
+    (one per `.IOLoop`). The keyword argument ``force_instance=True``
+    can be used to suppress this singleton behavior. Unless
+    ``force_instance=True`` is used, no arguments should be passed to
+    the `AsyncHTTPClient` constructor. The implementation subclass as
+    well as arguments to its constructor can be set with the static
+    method `configure()`
+
+    All `AsyncHTTPClient` implementations support a ``defaults``
+    keyword argument, which can be used to set default values for
+    `HTTPRequest` attributes.  For example::
+
+        AsyncHTTPClient.configure(
+            None, defaults=dict(user_agent="MyUserAgent"))
+        # or with force_instance:
+        client = AsyncHTTPClient(force_instance=True,
+            defaults=dict(user_agent="MyUserAgent"))
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    """
+
+    _instance_cache = None  # type: Dict[IOLoop, AsyncHTTPClient]
+
+    @classmethod
+    def configurable_base(cls) -> Type[Configurable]:
+        return AsyncHTTPClient
+
+    @classmethod
+    def configurable_default(cls) -> Type[Configurable]:
+        from tornado.simple_httpclient import SimpleAsyncHTTPClient
+
+        return SimpleAsyncHTTPClient
+
+    @classmethod
+    def _async_clients(cls) -> Dict[IOLoop, "AsyncHTTPClient"]:
+        attr_name = "_async_client_dict_" + cls.__name__
+        if not hasattr(cls, attr_name):
+            setattr(cls, attr_name, weakref.WeakKeyDictionary())
+        return getattr(cls, attr_name)
+
+    def __new__(cls, force_instance: bool = False, **kwargs: Any) -> "AsyncHTTPClient":
+        io_loop = IOLoop.current()
+        if force_instance:
+            instance_cache = None
+        else:
+            instance_cache = cls._async_clients()
+        if instance_cache is not None and io_loop in instance_cache:
+            return instance_cache[io_loop]
+        instance = super(AsyncHTTPClient, cls).__new__(cls, **kwargs)  # type: ignore
+        # Make sure the instance knows which cache to remove itself from.
+        # It can't simply call _async_clients() because we may be in
+        # __new__(AsyncHTTPClient) but instance.__class__ may be
+        # SimpleAsyncHTTPClient.
+        instance._instance_cache = instance_cache
+        if instance_cache is not None:
+            instance_cache[instance.io_loop] = instance
+        return instance
+
+    def initialize(self, defaults: Optional[Dict[str, Any]] = None) -> None:
+        self.io_loop = IOLoop.current()
+        self.defaults = dict(HTTPRequest._DEFAULTS)
+        if defaults is not None:
+            self.defaults.update(defaults)
+        self._closed = False
+
+    def close(self) -> None:
+        """Destroys this HTTP client, freeing any file descriptors used.
+
+        This method is **not needed in normal use** due to the way
+        that `AsyncHTTPClient` objects are transparently reused.
+        ``close()`` is generally only necessary when either the
+        `.IOLoop` is also being closed, or the ``force_instance=True``
+        argument was used when creating the `AsyncHTTPClient`.
+
+        No other methods may be called on the `AsyncHTTPClient` after
+        ``close()``.
+
+        """
+        if self._closed:
+            return
+        self._closed = True
+        if self._instance_cache is not None:
+            cached_val = self._instance_cache.pop(self.io_loop, None)
+            # If there's an object other than self in the instance
+            # cache for our IOLoop, something has gotten mixed up. A
+            # value of None appears to be possible when this is called
+            # from a destructor (HTTPClient.__del__) as the weakref
+            # gets cleared before the destructor runs.
+            if cached_val is not None and cached_val is not self:
+                raise RuntimeError("inconsistent AsyncHTTPClient cache")
+
+    def fetch(
+        self,
+        request: Union[str, "HTTPRequest"],
+        raise_error: bool = True,
+        **kwargs: Any
+    ) -> "Future[HTTPResponse]":
+        """Executes a request, asynchronously returning an `HTTPResponse`.
+
+        The request may be either a string URL or an `HTTPRequest` object.
+        If it is a string, we construct an `HTTPRequest` using any additional
+        kwargs: ``HTTPRequest(request, **kwargs)``
+
+        This method returns a `.Future` whose result is an
+        `HTTPResponse`. By default, the ``Future`` will raise an
+        `HTTPError` if the request returned a non-200 response code
+        (other errors may also be raised if the server could not be
+        contacted). Instead, if ``raise_error`` is set to False, the
+        response will always be returned regardless of the response
+        code.
+
+        If a ``callback`` is given, it will be invoked with the `HTTPResponse`.
+        In the callback interface, `HTTPError` is not automatically raised.
+        Instead, you must check the response's ``error`` attribute or
+        call its `~HTTPResponse.rethrow` method.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+           The ``raise_error=False`` argument only affects the
+           `HTTPError` raised when a non-200 response code is used,
+           instead of suppressing all errors.
+        """
+        if self._closed:
+            raise RuntimeError("fetch() called on closed AsyncHTTPClient")
+        if not isinstance(request, HTTPRequest):
+            request = HTTPRequest(url=request, **kwargs)
+        else:
+            if kwargs:
+                raise ValueError(
+                    "kwargs can't be used if request is an HTTPRequest object"
+                )
+        # We may modify this (to add Host, Accept-Encoding, etc),
+        # so make sure we don't modify the caller's object.  This is also
+        # where normal dicts get converted to HTTPHeaders objects.
+        request.headers = httputil.HTTPHeaders(request.headers)
+        request_proxy = _RequestProxy(request, self.defaults)
+        future = Future()  # type: Future[HTTPResponse]
+
+        def handle_response(response: "HTTPResponse") -> None:
+            if response.error:
+                if raise_error or not response._error_is_response_code:
+                    future_set_exception_unless_cancelled(future, response.error)
+                    return
+            future_set_result_unless_cancelled(future, response)
+
+        self.fetch_impl(cast(HTTPRequest, request_proxy), handle_response)
+        return future
+
+    def fetch_impl(
+        self, request: "HTTPRequest", callback: Callable[["HTTPResponse"], None]
+    ) -> None:
+        raise NotImplementedError()
+
+    @classmethod
+    def configure(
+        cls, impl: "Union[None, str, Type[Configurable]]", **kwargs: Any
+    ) -> None:
+        """Configures the `AsyncHTTPClient` subclass to use.
+
+        ``AsyncHTTPClient()`` actually creates an instance of a subclass.
+        This method may be called with either a class object or the
+        fully-qualified name of such a class (or ``None`` to use the default,
+        ``SimpleAsyncHTTPClient``)
+
+        If additional keyword arguments are given, they will be passed
+        to the constructor of each subclass instance created.  The
+        keyword argument ``max_clients`` determines the maximum number
+        of simultaneous `~AsyncHTTPClient.fetch()` operations that can
+        execute in parallel on each `.IOLoop`.  Additional arguments
+        may be supported depending on the implementation class in use.
+
+        Example::
+
+           AsyncHTTPClient.configure("tornado.curl_httpclient.CurlAsyncHTTPClient")
+        """
+        super(AsyncHTTPClient, cls).configure(impl, **kwargs)
+
+
+class HTTPRequest(object):
+    """HTTP client request object."""
+
+    _headers = None  # type: Union[Dict[str, str], httputil.HTTPHeaders]
+
+    # Default values for HTTPRequest parameters.
+    # Merged with the values on the request object by AsyncHTTPClient
+    # implementations.
+    _DEFAULTS = dict(
+        connect_timeout=20.0,
+        request_timeout=20.0,
+        follow_redirects=True,
+        max_redirects=5,
+        decompress_response=True,
+        proxy_password="",
+        allow_nonstandard_methods=False,
+        validate_cert=True,
+    )
+
+    def __init__(
+        self,
+        url: str,
+        method: str = "GET",
+        headers: Optional[Union[Dict[str, str], httputil.HTTPHeaders]] = None,
+        body: Optional[Union[bytes, str]] = None,
+        auth_username: Optional[str] = None,
+        auth_password: Optional[str] = None,
+        auth_mode: Optional[str] = None,
+        connect_timeout: Optional[float] = None,
+        request_timeout: Optional[float] = None,
+        if_modified_since: Optional[Union[float, datetime.datetime]] = None,
+        follow_redirects: Optional[bool] = None,
+        max_redirects: Optional[int] = None,
+        user_agent: Optional[str] = None,
+        use_gzip: Optional[bool] = None,
+        network_interface: Optional[str] = None,
+        streaming_callback: Optional[Callable[[bytes], None]] = None,
+        header_callback: Optional[Callable[[str], None]] = None,
+        prepare_curl_callback: Optional[Callable[[Any], None]] = None,
+        proxy_host: Optional[str] = None,
+        proxy_port: Optional[int] = None,
+        proxy_username: Optional[str] = None,
+        proxy_password: Optional[str] = None,
+        proxy_auth_mode: Optional[str] = None,
+        allow_nonstandard_methods: Optional[bool] = None,
+        validate_cert: Optional[bool] = None,
+        ca_certs: Optional[str] = None,
+        allow_ipv6: Optional[bool] = None,
+        client_key: Optional[str] = None,
+        client_cert: Optional[str] = None,
+        body_producer: Optional[
+            Callable[[Callable[[bytes], None]], "Future[None]"]
+        ] = None,
+        expect_100_continue: bool = False,
+        decompress_response: Optional[bool] = None,
+        ssl_options: Optional[Union[Dict[str, Any], ssl.SSLContext]] = None,
+    ) -> None:
+        r"""All parameters except ``url`` are optional.
+
+        :arg str url: URL to fetch
+        :arg str method: HTTP method, e.g. "GET" or "POST"
+        :arg headers: Additional HTTP headers to pass on the request
+        :type headers: `~tornado.httputil.HTTPHeaders` or `dict`
+        :arg body: HTTP request body as a string (byte or unicode; if unicode
+           the utf-8 encoding will be used)
+        :type body: `str` or `bytes`
+        :arg collections.abc.Callable body_producer: Callable used for
+           lazy/asynchronous request bodies.
+           It is called with one argument, a ``write`` function, and should
+           return a `.Future`.  It should call the write function with new
+           data as it becomes available.  The write function returns a
+           `.Future` which can be used for flow control.
+           Only one of ``body`` and ``body_producer`` may
+           be specified.  ``body_producer`` is not supported on
+           ``curl_httpclient``.  When using ``body_producer`` it is recommended
+           to pass a ``Content-Length`` in the headers as otherwise chunked
+           encoding will be used, and many servers do not support chunked
+           encoding on requests.  New in Tornado 4.0
+        :arg str auth_username: Username for HTTP authentication
+        :arg str auth_password: Password for HTTP authentication
+        :arg str auth_mode: Authentication mode; default is "basic".
+           Allowed values are implementation-defined; ``curl_httpclient``
+           supports "basic" and "digest"; ``simple_httpclient`` only supports
+           "basic"
+        :arg float connect_timeout: Timeout for initial connection in seconds,
+           default 20 seconds (0 means no timeout)
+        :arg float request_timeout: Timeout for entire request in seconds,
+           default 20 seconds (0 means no timeout)
+        :arg if_modified_since: Timestamp for ``If-Modified-Since`` header
+        :type if_modified_since: `datetime` or `float`
+        :arg bool follow_redirects: Should redirects be followed automatically
+           or return the 3xx response? Default True.
+        :arg int max_redirects: Limit for ``follow_redirects``, default 5.
+        :arg str user_agent: String to send as ``User-Agent`` header
+        :arg bool decompress_response: Request a compressed response from
+           the server and decompress it after downloading.  Default is True.
+           New in Tornado 4.0.
+        :arg bool use_gzip: Deprecated alias for ``decompress_response``
+           since Tornado 4.0.
+        :arg str network_interface: Network interface or source IP to use for request.
+           See ``curl_httpclient`` note below.
+        :arg collections.abc.Callable streaming_callback: If set, ``streaming_callback`` will
+           be run with each chunk of data as it is received, and
+           ``HTTPResponse.body`` and ``HTTPResponse.buffer`` will be empty in
+           the final response.
+        :arg collections.abc.Callable header_callback: If set, ``header_callback`` will
+           be run with each header line as it is received (including the
+           first line, e.g. ``HTTP/1.0 200 OK\r\n``, and a final line
+           containing only ``\r\n``.  All lines include the trailing newline
+           characters).  ``HTTPResponse.headers`` will be empty in the final
+           response.  This is most useful in conjunction with
+           ``streaming_callback``, because it's the only way to get access to
+           header data while the request is in progress.
+        :arg collections.abc.Callable prepare_curl_callback: If set, will be called with
+           a ``pycurl.Curl`` object to allow the application to make additional
+           ``setopt`` calls.
+        :arg str proxy_host: HTTP proxy hostname.  To use proxies,
+           ``proxy_host`` and ``proxy_port`` must be set; ``proxy_username``,
+           ``proxy_pass`` and ``proxy_auth_mode`` are optional.  Proxies are
+           currently only supported with ``curl_httpclient``.
+        :arg int proxy_port: HTTP proxy port
+        :arg str proxy_username: HTTP proxy username
+        :arg str proxy_password: HTTP proxy password
+        :arg str proxy_auth_mode: HTTP proxy Authentication mode;
+           default is "basic". supports "basic" and "digest"
+        :arg bool allow_nonstandard_methods: Allow unknown values for ``method``
+           argument? Default is False.
+        :arg bool validate_cert: For HTTPS requests, validate the server's
+           certificate? Default is True.
+        :arg str ca_certs: filename of CA certificates in PEM format,
+           or None to use defaults.  See note below when used with
+           ``curl_httpclient``.
+        :arg str client_key: Filename for client SSL key, if any.  See
+           note below when used with ``curl_httpclient``.
+        :arg str client_cert: Filename for client SSL certificate, if any.
+           See note below when used with ``curl_httpclient``.
+        :arg ssl.SSLContext ssl_options: `ssl.SSLContext` object for use in
+           ``simple_httpclient`` (unsupported by ``curl_httpclient``).
+           Overrides ``validate_cert``, ``ca_certs``, ``client_key``,
+           and ``client_cert``.
+        :arg bool allow_ipv6: Use IPv6 when available?  Default is True.
+        :arg bool expect_100_continue: If true, send the
+           ``Expect: 100-continue`` header and wait for a continue response
+           before sending the request body.  Only supported with
+           ``simple_httpclient``.
+
+        .. note::
+
+            When using ``curl_httpclient`` certain options may be
+            inherited by subsequent fetches because ``pycurl`` does
+            not allow them to be cleanly reset.  This applies to the
+            ``ca_certs``, ``client_key``, ``client_cert``, and
+            ``network_interface`` arguments.  If you use these
+            options, you should pass them on every request (you don't
+            have to always use the same values, but it's not possible
+            to mix requests that specify these options with ones that
+            use the defaults).
+
+        .. versionadded:: 3.1
+           The ``auth_mode`` argument.
+
+        .. versionadded:: 4.0
+           The ``body_producer`` and ``expect_100_continue`` arguments.
+
+        .. versionadded:: 4.2
+           The ``ssl_options`` argument.
+
+        .. versionadded:: 4.5
+           The ``proxy_auth_mode`` argument.
+        """
+        # Note that some of these attributes go through property setters
+        # defined below.
+        self.headers = headers  # type: ignore
+        if if_modified_since:
+            self.headers["If-Modified-Since"] = httputil.format_timestamp(
+                if_modified_since
+            )
+        self.proxy_host = proxy_host
+        self.proxy_port = proxy_port
+        self.proxy_username = proxy_username
+        self.proxy_password = proxy_password
+        self.proxy_auth_mode = proxy_auth_mode
+        self.url = url
+        self.method = method
+        self.body = body  # type: ignore
+        self.body_producer = body_producer
+        self.auth_username = auth_username
+        self.auth_password = auth_password
+        self.auth_mode = auth_mode
+        self.connect_timeout = connect_timeout
+        self.request_timeout = request_timeout
+        self.follow_redirects = follow_redirects
+        self.max_redirects = max_redirects
+        self.user_agent = user_agent
+        if decompress_response is not None:
+            self.decompress_response = decompress_response  # type: Optional[bool]
+        else:
+            self.decompress_response = use_gzip
+        self.network_interface = network_interface
+        self.streaming_callback = streaming_callback
+        self.header_callback = header_callback
+        self.prepare_curl_callback = prepare_curl_callback
+        self.allow_nonstandard_methods = allow_nonstandard_methods
+        self.validate_cert = validate_cert
+        self.ca_certs = ca_certs
+        self.allow_ipv6 = allow_ipv6
+        self.client_key = client_key
+        self.client_cert = client_cert
+        self.ssl_options = ssl_options
+        self.expect_100_continue = expect_100_continue
+        self.start_time = time.time()
+
+    @property
+    def headers(self) -> httputil.HTTPHeaders:
+        # TODO: headers may actually be a plain dict until fairly late in
+        # the process (AsyncHTTPClient.fetch), but practically speaking,
+        # whenever the property is used they're already HTTPHeaders.
+        return self._headers  # type: ignore
+
+    @headers.setter
+    def headers(self, value: Union[Dict[str, str], httputil.HTTPHeaders]) -> None:
+        if value is None:
+            self._headers = httputil.HTTPHeaders()
+        else:
+            self._headers = value  # type: ignore
+
+    @property
+    def body(self) -> bytes:
+        return self._body
+
+    @body.setter
+    def body(self, value: Union[bytes, str]) -> None:
+        self._body = utf8(value)
+
+
+class HTTPResponse(object):
+    """HTTP Response object.
+
+    Attributes:
+
+    * ``request``: HTTPRequest object
+
+    * ``code``: numeric HTTP status code, e.g. 200 or 404
+
+    * ``reason``: human-readable reason phrase describing the status code
+
+    * ``headers``: `tornado.httputil.HTTPHeaders` object
+
+    * ``effective_url``: final location of the resource after following any
+      redirects
+
+    * ``buffer``: ``cStringIO`` object for response body
+
+    * ``body``: response body as bytes (created on demand from ``self.buffer``)
+
+    * ``error``: Exception object, if any
+
+    * ``request_time``: seconds from request start to finish. Includes all
+      network operations from DNS resolution to receiving the last byte of
+      data. Does not include time spent in the queue (due to the
+      ``max_clients`` option). If redirects were followed, only includes
+      the final request.
+
+    * ``start_time``: Time at which the HTTP operation started, based on
+      `time.time` (not the monotonic clock used by `.IOLoop.time`). May
+      be ``None`` if the request timed out while in the queue.
+
+    * ``time_info``: dictionary of diagnostic timing information from the
+      request. Available data are subject to change, but currently uses timings
+      available from http://curl.haxx.se/libcurl/c/curl_easy_getinfo.html,
+      plus ``queue``, which is the delay (if any) introduced by waiting for
+      a slot under `AsyncHTTPClient`'s ``max_clients`` setting.
+
+    .. versionadded:: 5.1
+
+       Added the ``start_time`` attribute.
+
+    .. versionchanged:: 5.1
+
+       The ``request_time`` attribute previously included time spent in the queue
+       for ``simple_httpclient``, but not in ``curl_httpclient``. Now queueing time
+       is excluded in both implementations. ``request_time`` is now more accurate for
+       ``curl_httpclient`` because it uses a monotonic clock when available.
+    """
+
+    # I'm not sure why these don't get type-inferred from the references in __init__.
+    error = None  # type: Optional[BaseException]
+    _error_is_response_code = False
+    request = None  # type: HTTPRequest
+
+    def __init__(
+        self,
+        request: HTTPRequest,
+        code: int,
+        headers: Optional[httputil.HTTPHeaders] = None,
+        buffer: Optional[BytesIO] = None,
+        effective_url: Optional[str] = None,
+        error: Optional[BaseException] = None,
+        request_time: Optional[float] = None,
+        time_info: Optional[Dict[str, float]] = None,
+        reason: Optional[str] = None,
+        start_time: Optional[float] = None,
+    ) -> None:
+        if isinstance(request, _RequestProxy):
+            self.request = request.request
+        else:
+            self.request = request
+        self.code = code
+        self.reason = reason or httputil.responses.get(code, "Unknown")
+        if headers is not None:
+            self.headers = headers
+        else:
+            self.headers = httputil.HTTPHeaders()
+        self.buffer = buffer
+        self._body = None  # type: Optional[bytes]
+        if effective_url is None:
+            self.effective_url = request.url
+        else:
+            self.effective_url = effective_url
+        self._error_is_response_code = False
+        if error is None:
+            if self.code < 200 or self.code >= 300:
+                self._error_is_response_code = True
+                self.error = HTTPError(self.code, message=self.reason, response=self)
+            else:
+                self.error = None
+        else:
+            self.error = error
+        self.start_time = start_time
+        self.request_time = request_time
+        self.time_info = time_info or {}
+
+    @property
+    def body(self) -> bytes:
+        if self.buffer is None:
+            return b""
+        elif self._body is None:
+            self._body = self.buffer.getvalue()
+
+        return self._body
+
+    def rethrow(self) -> None:
+        """If there was an error on the request, raise an `HTTPError`."""
+        if self.error:
+            raise self.error
+
+    def __repr__(self) -> str:
+        args = ",".join("%s=%r" % i for i in sorted(self.__dict__.items()))
+        return "%s(%s)" % (self.__class__.__name__, args)
+
+
+class HTTPClientError(Exception):
+    """Exception thrown for an unsuccessful HTTP request.
+
+    Attributes:
+
+    * ``code`` - HTTP error integer error code, e.g. 404.  Error code 599 is
+      used when no HTTP response was received, e.g. for a timeout.
+
+    * ``response`` - `HTTPResponse` object, if any.
+
+    Note that if ``follow_redirects`` is False, redirects become HTTPErrors,
+    and you can look at ``error.response.headers['Location']`` to see the
+    destination of the redirect.
+
+    .. versionchanged:: 5.1
+
+       Renamed from ``HTTPError`` to ``HTTPClientError`` to avoid collisions with
+       `tornado.web.HTTPError`. The name ``tornado.httpclient.HTTPError`` remains
+       as an alias.
+    """
+
+    def __init__(
+        self,
+        code: int,
+        message: Optional[str] = None,
+        response: Optional[HTTPResponse] = None,
+    ) -> None:
+        self.code = code
+        self.message = message or httputil.responses.get(code, "Unknown")
+        self.response = response
+        super().__init__(code, message, response)
+
+    def __str__(self) -> str:
+        return "HTTP %d: %s" % (self.code, self.message)
+
+    # There is a cyclic reference between self and self.response,
+    # which breaks the default __repr__ implementation.
+    # (especially on pypy, which doesn't have the same recursion
+    # detection as cpython).
+    __repr__ = __str__
+
+
+HTTPError = HTTPClientError
+
+
+class _RequestProxy(object):
+    """Combines an object with a dictionary of defaults.
+
+    Used internally by AsyncHTTPClient implementations.
+    """
+
+    def __init__(
+        self, request: HTTPRequest, defaults: Optional[Dict[str, Any]]
+    ) -> None:
+        self.request = request
+        self.defaults = defaults
+
+    def __getattr__(self, name: str) -> Any:
+        request_attr = getattr(self.request, name)
+        if request_attr is not None:
+            return request_attr
+        elif self.defaults is not None:
+            return self.defaults.get(name, None)
+        else:
+            return None
+
+
+def main() -> None:
+    from tornado.options import define, options, parse_command_line
+
+    define("print_headers", type=bool, default=False)
+    define("print_body", type=bool, default=True)
+    define("follow_redirects", type=bool, default=True)
+    define("validate_cert", type=bool, default=True)
+    define("proxy_host", type=str)
+    define("proxy_port", type=int)
+    args = parse_command_line()
+    client = HTTPClient()
+    for arg in args:
+        try:
+            response = client.fetch(
+                arg,
+                follow_redirects=options.follow_redirects,
+                validate_cert=options.validate_cert,
+                proxy_host=options.proxy_host,
+                proxy_port=options.proxy_port,
+            )
+        except HTTPError as e:
+            if e.response is not None:
+                response = e.response
+            else:
+                raise
+        if options.print_headers:
+            print(response.headers)
+        if options.print_body:
+            print(native_str(response.body))
+    client.close()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/httpserver.py b/venv/lib/python3.9/site-packages/tornado/httpserver.py
new file mode 100644
index 00000000..77dc541e
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/httpserver.py
@@ -0,0 +1,410 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""A non-blocking, single-threaded HTTP server.
+
+Typical applications have little direct interaction with the `HTTPServer`
+class except to start a server at the beginning of the process
+(and even that is often done indirectly via `tornado.web.Application.listen`).
+
+.. versionchanged:: 4.0
+
+   The ``HTTPRequest`` class that used to live in this module has been moved
+   to `tornado.httputil.HTTPServerRequest`.  The old name remains as an alias.
+"""
+
+import socket
+import ssl
+
+from tornado.escape import native_str
+from tornado.http1connection import HTTP1ServerConnection, HTTP1ConnectionParameters
+from tornado import httputil
+from tornado import iostream
+from tornado import netutil
+from tornado.tcpserver import TCPServer
+from tornado.util import Configurable
+
+import typing
+from typing import Union, Any, Dict, Callable, List, Type, Tuple, Optional, Awaitable
+
+if typing.TYPE_CHECKING:
+    from typing import Set  # noqa: F401
+
+
+class HTTPServer(TCPServer, Configurable, httputil.HTTPServerConnectionDelegate):
+    r"""A non-blocking, single-threaded HTTP server.
+
+    A server is defined by a subclass of `.HTTPServerConnectionDelegate`,
+    or, for backwards compatibility, a callback that takes an
+    `.HTTPServerRequest` as an argument. The delegate is usually a
+    `tornado.web.Application`.
+
+    `HTTPServer` supports keep-alive connections by default
+    (automatically for HTTP/1.1, or for HTTP/1.0 when the client
+    requests ``Connection: keep-alive``).
+
+    If ``xheaders`` is ``True``, we support the
+    ``X-Real-Ip``/``X-Forwarded-For`` and
+    ``X-Scheme``/``X-Forwarded-Proto`` headers, which override the
+    remote IP and URI scheme/protocol for all requests.  These headers
+    are useful when running Tornado behind a reverse proxy or load
+    balancer.  The ``protocol`` argument can also be set to ``https``
+    if Tornado is run behind an SSL-decoding proxy that does not set one of
+    the supported ``xheaders``.
+
+    By default, when parsing the ``X-Forwarded-For`` header, Tornado will
+    select the last (i.e., the closest) address on the list of hosts as the
+    remote host IP address.  To select the next server in the chain, a list of
+    trusted downstream hosts may be passed as the ``trusted_downstream``
+    argument.  These hosts will be skipped when parsing the ``X-Forwarded-For``
+    header.
+
+    To make this server serve SSL traffic, send the ``ssl_options`` keyword
+    argument with an `ssl.SSLContext` object. For compatibility with older
+    versions of Python ``ssl_options`` may also be a dictionary of keyword
+    arguments for the `ssl.wrap_socket` method.::
+
+       ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+       ssl_ctx.load_cert_chain(os.path.join(data_dir, "mydomain.crt"),
+                               os.path.join(data_dir, "mydomain.key"))
+       HTTPServer(application, ssl_options=ssl_ctx)
+
+    `HTTPServer` initialization follows one of three patterns (the
+    initialization methods are defined on `tornado.tcpserver.TCPServer`):
+
+    1. `~tornado.tcpserver.TCPServer.listen`: single-process::
+
+            async def main():
+                server = HTTPServer()
+                server.listen(8888)
+                await asyncio.Event.wait()
+
+            asyncio.run(main())
+
+       In many cases, `tornado.web.Application.listen` can be used to avoid
+       the need to explicitly create the `HTTPServer`.
+
+       While this example does not create multiple processes on its own, when
+       the ``reuse_port=True`` argument is passed to ``listen()`` you can run
+       the program multiple times to create a multi-process service.
+
+    2. `~tornado.tcpserver.TCPServer.add_sockets`: multi-process::
+
+            sockets = bind_sockets(8888)
+            tornado.process.fork_processes(0)
+            async def post_fork_main():
+                server = HTTPServer()
+                server.add_sockets(sockets)
+                await asyncio.Event().wait()
+            asyncio.run(post_fork_main())
+
+       The ``add_sockets`` interface is more complicated, but it can be used with
+       `tornado.process.fork_processes` to run a multi-process service with all
+       worker processes forked from a single parent.  ``add_sockets`` can also be
+       used in single-process servers if you want to create your listening
+       sockets in some way other than `~tornado.netutil.bind_sockets`.
+
+       Note that when using this pattern, nothing that touches the event loop
+       can be run before ``fork_processes``.
+
+    3. `~tornado.tcpserver.TCPServer.bind`/`~tornado.tcpserver.TCPServer.start`:
+       simple **deprecated** multi-process::
+
+            server = HTTPServer()
+            server.bind(8888)
+            server.start(0)  # Forks multiple sub-processes
+            IOLoop.current().start()
+
+       This pattern is deprecated because it requires interfaces in the
+       `asyncio` module that have been deprecated since Python 3.10. Support for
+       creating multiple processes in the ``start`` method will be removed in a
+       future version of Tornado.
+
+    .. versionchanged:: 4.0
+       Added ``decompress_request``, ``chunk_size``, ``max_header_size``,
+       ``idle_connection_timeout``, ``body_timeout``, ``max_body_size``
+       arguments.  Added support for `.HTTPServerConnectionDelegate`
+       instances as ``request_callback``.
+
+    .. versionchanged:: 4.1
+       `.HTTPServerConnectionDelegate.start_request` is now called with
+       two arguments ``(server_conn, request_conn)`` (in accordance with the
+       documentation) instead of one ``(request_conn)``.
+
+    .. versionchanged:: 4.2
+       `HTTPServer` is now a subclass of `tornado.util.Configurable`.
+
+    .. versionchanged:: 4.5
+       Added the ``trusted_downstream`` argument.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument has been removed.
+    """
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        # Ignore args to __init__; real initialization belongs in
+        # initialize since we're Configurable. (there's something
+        # weird in initialization order between this class,
+        # Configurable, and TCPServer so we can't leave __init__ out
+        # completely)
+        pass
+
+    def initialize(
+        self,
+        request_callback: Union[
+            httputil.HTTPServerConnectionDelegate,
+            Callable[[httputil.HTTPServerRequest], None],
+        ],
+        no_keep_alive: bool = False,
+        xheaders: bool = False,
+        ssl_options: Optional[Union[Dict[str, Any], ssl.SSLContext]] = None,
+        protocol: Optional[str] = None,
+        decompress_request: bool = False,
+        chunk_size: Optional[int] = None,
+        max_header_size: Optional[int] = None,
+        idle_connection_timeout: Optional[float] = None,
+        body_timeout: Optional[float] = None,
+        max_body_size: Optional[int] = None,
+        max_buffer_size: Optional[int] = None,
+        trusted_downstream: Optional[List[str]] = None,
+    ) -> None:
+        # This method's signature is not extracted with autodoc
+        # because we want its arguments to appear on the class
+        # constructor. When changing this signature, also update the
+        # copy in httpserver.rst.
+        self.request_callback = request_callback
+        self.xheaders = xheaders
+        self.protocol = protocol
+        self.conn_params = HTTP1ConnectionParameters(
+            decompress=decompress_request,
+            chunk_size=chunk_size,
+            max_header_size=max_header_size,
+            header_timeout=idle_connection_timeout or 3600,
+            max_body_size=max_body_size,
+            body_timeout=body_timeout,
+            no_keep_alive=no_keep_alive,
+        )
+        TCPServer.__init__(
+            self,
+            ssl_options=ssl_options,
+            max_buffer_size=max_buffer_size,
+            read_chunk_size=chunk_size,
+        )
+        self._connections = set()  # type: Set[HTTP1ServerConnection]
+        self.trusted_downstream = trusted_downstream
+
+    @classmethod
+    def configurable_base(cls) -> Type[Configurable]:
+        return HTTPServer
+
+    @classmethod
+    def configurable_default(cls) -> Type[Configurable]:
+        return HTTPServer
+
+    async def close_all_connections(self) -> None:
+        """Close all open connections and asynchronously wait for them to finish.
+
+        This method is used in combination with `~.TCPServer.stop` to
+        support clean shutdowns (especially for unittests). Typical
+        usage would call ``stop()`` first to stop accepting new
+        connections, then ``await close_all_connections()`` to wait for
+        existing connections to finish.
+
+        This method does not currently close open websocket connections.
+
+        Note that this method is a coroutine and must be called with ``await``.
+
+        """
+        while self._connections:
+            # Peek at an arbitrary element of the set
+            conn = next(iter(self._connections))
+            await conn.close()
+
+    def handle_stream(self, stream: iostream.IOStream, address: Tuple) -> None:
+        context = _HTTPRequestContext(
+            stream, address, self.protocol, self.trusted_downstream
+        )
+        conn = HTTP1ServerConnection(stream, self.conn_params, context)
+        self._connections.add(conn)
+        conn.start_serving(self)
+
+    def start_request(
+        self, server_conn: object, request_conn: httputil.HTTPConnection
+    ) -> httputil.HTTPMessageDelegate:
+        if isinstance(self.request_callback, httputil.HTTPServerConnectionDelegate):
+            delegate = self.request_callback.start_request(server_conn, request_conn)
+        else:
+            delegate = _CallableAdapter(self.request_callback, request_conn)
+
+        if self.xheaders:
+            delegate = _ProxyAdapter(delegate, request_conn)
+
+        return delegate
+
+    def on_close(self, server_conn: object) -> None:
+        self._connections.remove(typing.cast(HTTP1ServerConnection, server_conn))
+
+
+class _CallableAdapter(httputil.HTTPMessageDelegate):
+    def __init__(
+        self,
+        request_callback: Callable[[httputil.HTTPServerRequest], None],
+        request_conn: httputil.HTTPConnection,
+    ) -> None:
+        self.connection = request_conn
+        self.request_callback = request_callback
+        self.request = None  # type: Optional[httputil.HTTPServerRequest]
+        self.delegate = None
+        self._chunks = []  # type: List[bytes]
+
+    def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        self.request = httputil.HTTPServerRequest(
+            connection=self.connection,
+            start_line=typing.cast(httputil.RequestStartLine, start_line),
+            headers=headers,
+        )
+        return None
+
+    def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
+        self._chunks.append(chunk)
+        return None
+
+    def finish(self) -> None:
+        assert self.request is not None
+        self.request.body = b"".join(self._chunks)
+        self.request._parse_body()
+        self.request_callback(self.request)
+
+    def on_connection_close(self) -> None:
+        del self._chunks
+
+
+class _HTTPRequestContext(object):
+    def __init__(
+        self,
+        stream: iostream.IOStream,
+        address: Tuple,
+        protocol: Optional[str],
+        trusted_downstream: Optional[List[str]] = None,
+    ) -> None:
+        self.address = address
+        # Save the socket's address family now so we know how to
+        # interpret self.address even after the stream is closed
+        # and its socket attribute replaced with None.
+        if stream.socket is not None:
+            self.address_family = stream.socket.family
+        else:
+            self.address_family = None
+        # In HTTPServerRequest we want an IP, not a full socket address.
+        if (
+            self.address_family in (socket.AF_INET, socket.AF_INET6)
+            and address is not None
+        ):
+            self.remote_ip = address[0]
+        else:
+            # Unix (or other) socket; fake the remote address.
+            self.remote_ip = "0.0.0.0"
+        if protocol:
+            self.protocol = protocol
+        elif isinstance(stream, iostream.SSLIOStream):
+            self.protocol = "https"
+        else:
+            self.protocol = "http"
+        self._orig_remote_ip = self.remote_ip
+        self._orig_protocol = self.protocol
+        self.trusted_downstream = set(trusted_downstream or [])
+
+    def __str__(self) -> str:
+        if self.address_family in (socket.AF_INET, socket.AF_INET6):
+            return self.remote_ip
+        elif isinstance(self.address, bytes):
+            # Python 3 with the -bb option warns about str(bytes),
+            # so convert it explicitly.
+            # Unix socket addresses are str on mac but bytes on linux.
+            return native_str(self.address)
+        else:
+            return str(self.address)
+
+    def _apply_xheaders(self, headers: httputil.HTTPHeaders) -> None:
+        """Rewrite the ``remote_ip`` and ``protocol`` fields."""
+        # Squid uses X-Forwarded-For, others use X-Real-Ip
+        ip = headers.get("X-Forwarded-For", self.remote_ip)
+        # Skip trusted downstream hosts in X-Forwarded-For list
+        for ip in (cand.strip() for cand in reversed(ip.split(","))):
+            if ip not in self.trusted_downstream:
+                break
+        ip = headers.get("X-Real-Ip", ip)
+        if netutil.is_valid_ip(ip):
+            self.remote_ip = ip
+        # AWS uses X-Forwarded-Proto
+        proto_header = headers.get(
+            "X-Scheme", headers.get("X-Forwarded-Proto", self.protocol)
+        )
+        if proto_header:
+            # use only the last proto entry if there is more than one
+            # TODO: support trusting multiple layers of proxied protocol
+            proto_header = proto_header.split(",")[-1].strip()
+        if proto_header in ("http", "https"):
+            self.protocol = proto_header
+
+    def _unapply_xheaders(self) -> None:
+        """Undo changes from `_apply_xheaders`.
+
+        Xheaders are per-request so they should not leak to the next
+        request on the same connection.
+        """
+        self.remote_ip = self._orig_remote_ip
+        self.protocol = self._orig_protocol
+
+
+class _ProxyAdapter(httputil.HTTPMessageDelegate):
+    def __init__(
+        self,
+        delegate: httputil.HTTPMessageDelegate,
+        request_conn: httputil.HTTPConnection,
+    ) -> None:
+        self.connection = request_conn
+        self.delegate = delegate
+
+    def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        # TODO: either make context an official part of the
+        # HTTPConnection interface or figure out some other way to do this.
+        self.connection.context._apply_xheaders(headers)  # type: ignore
+        return self.delegate.headers_received(start_line, headers)
+
+    def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
+        return self.delegate.data_received(chunk)
+
+    def finish(self) -> None:
+        self.delegate.finish()
+        self._cleanup()
+
+    def on_connection_close(self) -> None:
+        self.delegate.on_connection_close()
+        self._cleanup()
+
+    def _cleanup(self) -> None:
+        self.connection.context._unapply_xheaders()  # type: ignore
+
+
+HTTPRequest = httputil.HTTPServerRequest
diff --git a/venv/lib/python3.9/site-packages/tornado/httputil.py b/venv/lib/python3.9/site-packages/tornado/httputil.py
new file mode 100644
index 00000000..9c341d47
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/httputil.py
@@ -0,0 +1,1134 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""HTTP utility code shared by clients and servers.
+
+This module also defines the `HTTPServerRequest` class which is exposed
+via `tornado.web.RequestHandler.request`.
+"""
+
+import calendar
+import collections.abc
+import copy
+import datetime
+import email.utils
+from functools import lru_cache
+from http.client import responses
+import http.cookies
+import re
+from ssl import SSLError
+import time
+import unicodedata
+from urllib.parse import urlencode, urlparse, urlunparse, parse_qsl
+
+from tornado.escape import native_str, parse_qs_bytes, utf8
+from tornado.log import gen_log
+from tornado.util import ObjectDict, unicode_type
+
+
+# responses is unused in this file, but we re-export it to other files.
+# Reference it so pyflakes doesn't complain.
+responses
+
+import typing
+from typing import (
+    Tuple,
+    Iterable,
+    List,
+    Mapping,
+    Iterator,
+    Dict,
+    Union,
+    Optional,
+    Awaitable,
+    Generator,
+    AnyStr,
+)
+
+if typing.TYPE_CHECKING:
+    from typing import Deque  # noqa: F401
+    from asyncio import Future  # noqa: F401
+    import unittest  # noqa: F401
+
+
+@lru_cache(1000)
+def _normalize_header(name: str) -> str:
+    """Map a header name to Http-Header-Case.
+
+    >>> _normalize_header("coNtent-TYPE")
+    'Content-Type'
+    """
+    return "-".join([w.capitalize() for w in name.split("-")])
+
+
+class HTTPHeaders(collections.abc.MutableMapping):
+    """A dictionary that maintains ``Http-Header-Case`` for all keys.
+
+    Supports multiple values per key via a pair of new methods,
+    `add()` and `get_list()`.  The regular dictionary interface
+    returns a single value per key, with multiple values joined by a
+    comma.
+
+    >>> h = HTTPHeaders({"content-type": "text/html"})
+    >>> list(h.keys())
+    ['Content-Type']
+    >>> h["Content-Type"]
+    'text/html'
+
+    >>> h.add("Set-Cookie", "A=B")
+    >>> h.add("Set-Cookie", "C=D")
+    >>> h["set-cookie"]
+    'A=B,C=D'
+    >>> h.get_list("set-cookie")
+    ['A=B', 'C=D']
+
+    >>> for (k,v) in sorted(h.get_all()):
+    ...    print('%s: %s' % (k,v))
+    ...
+    Content-Type: text/html
+    Set-Cookie: A=B
+    Set-Cookie: C=D
+    """
+
+    @typing.overload
+    def __init__(self, __arg: Mapping[str, List[str]]) -> None:
+        pass
+
+    @typing.overload  # noqa: F811
+    def __init__(self, __arg: Mapping[str, str]) -> None:
+        pass
+
+    @typing.overload  # noqa: F811
+    def __init__(self, *args: Tuple[str, str]) -> None:
+        pass
+
+    @typing.overload  # noqa: F811
+    def __init__(self, **kwargs: str) -> None:
+        pass
+
+    def __init__(self, *args: typing.Any, **kwargs: str) -> None:  # noqa: F811
+        self._dict = {}  # type: typing.Dict[str, str]
+        self._as_list = {}  # type: typing.Dict[str, typing.List[str]]
+        self._last_key = None  # type: Optional[str]
+        if len(args) == 1 and len(kwargs) == 0 and isinstance(args[0], HTTPHeaders):
+            # Copy constructor
+            for k, v in args[0].get_all():
+                self.add(k, v)
+        else:
+            # Dict-style initialization
+            self.update(*args, **kwargs)
+
+    # new public methods
+
+    def add(self, name: str, value: str) -> None:
+        """Adds a new value for the given key."""
+        norm_name = _normalize_header(name)
+        self._last_key = norm_name
+        if norm_name in self:
+            self._dict[norm_name] = (
+                native_str(self[norm_name]) + "," + native_str(value)
+            )
+            self._as_list[norm_name].append(value)
+        else:
+            self[norm_name] = value
+
+    def get_list(self, name: str) -> List[str]:
+        """Returns all values for the given header as a list."""
+        norm_name = _normalize_header(name)
+        return self._as_list.get(norm_name, [])
+
+    def get_all(self) -> Iterable[Tuple[str, str]]:
+        """Returns an iterable of all (name, value) pairs.
+
+        If a header has multiple values, multiple pairs will be
+        returned with the same name.
+        """
+        for name, values in self._as_list.items():
+            for value in values:
+                yield (name, value)
+
+    def parse_line(self, line: str) -> None:
+        """Updates the dictionary with a single header line.
+
+        >>> h = HTTPHeaders()
+        >>> h.parse_line("Content-Type: text/html")
+        >>> h.get('content-type')
+        'text/html'
+        """
+        if line[0].isspace():
+            # continuation of a multi-line header
+            if self._last_key is None:
+                raise HTTPInputError("first header line cannot start with whitespace")
+            new_part = " " + line.lstrip()
+            self._as_list[self._last_key][-1] += new_part
+            self._dict[self._last_key] += new_part
+        else:
+            try:
+                name, value = line.split(":", 1)
+            except ValueError:
+                raise HTTPInputError("no colon in header line")
+            self.add(name, value.strip())
+
+    @classmethod
+    def parse(cls, headers: str) -> "HTTPHeaders":
+        """Returns a dictionary from HTTP header text.
+
+        >>> h = HTTPHeaders.parse("Content-Type: text/html\\r\\nContent-Length: 42\\r\\n")
+        >>> sorted(h.items())
+        [('Content-Length', '42'), ('Content-Type', 'text/html')]
+
+        .. versionchanged:: 5.1
+
+           Raises `HTTPInputError` on malformed headers instead of a
+           mix of `KeyError`, and `ValueError`.
+
+        """
+        h = cls()
+        # RFC 7230 section 3.5: a recipient MAY recognize a single LF as a line
+        # terminator and ignore any preceding CR.
+        for line in headers.split("\n"):
+            if line.endswith("\r"):
+                line = line[:-1]
+            if line:
+                h.parse_line(line)
+        return h
+
+    # MutableMapping abstract method implementations.
+
+    def __setitem__(self, name: str, value: str) -> None:
+        norm_name = _normalize_header(name)
+        self._dict[norm_name] = value
+        self._as_list[norm_name] = [value]
+
+    def __getitem__(self, name: str) -> str:
+        return self._dict[_normalize_header(name)]
+
+    def __delitem__(self, name: str) -> None:
+        norm_name = _normalize_header(name)
+        del self._dict[norm_name]
+        del self._as_list[norm_name]
+
+    def __len__(self) -> int:
+        return len(self._dict)
+
+    def __iter__(self) -> Iterator[typing.Any]:
+        return iter(self._dict)
+
+    def copy(self) -> "HTTPHeaders":
+        # defined in dict but not in MutableMapping.
+        return HTTPHeaders(self)
+
+    # Use our overridden copy method for the copy.copy module.
+    # This makes shallow copies one level deeper, but preserves
+    # the appearance that HTTPHeaders is a single container.
+    __copy__ = copy
+
+    def __str__(self) -> str:
+        lines = []
+        for name, value in self.get_all():
+            lines.append("%s: %s\n" % (name, value))
+        return "".join(lines)
+
+    __unicode__ = __str__
+
+
+class HTTPServerRequest(object):
+    """A single HTTP request.
+
+    All attributes are type `str` unless otherwise noted.
+
+    .. attribute:: method
+
+       HTTP request method, e.g. "GET" or "POST"
+
+    .. attribute:: uri
+
+       The requested uri.
+
+    .. attribute:: path
+
+       The path portion of `uri`
+
+    .. attribute:: query
+
+       The query portion of `uri`
+
+    .. attribute:: version
+
+       HTTP version specified in request, e.g. "HTTP/1.1"
+
+    .. attribute:: headers
+
+       `.HTTPHeaders` dictionary-like object for request headers.  Acts like
+       a case-insensitive dictionary with additional methods for repeated
+       headers.
+
+    .. attribute:: body
+
+       Request body, if present, as a byte string.
+
+    .. attribute:: remote_ip
+
+       Client's IP address as a string.  If ``HTTPServer.xheaders`` is set,
+       will pass along the real IP address provided by a load balancer
+       in the ``X-Real-Ip`` or ``X-Forwarded-For`` header.
+
+    .. versionchanged:: 3.1
+       The list format of ``X-Forwarded-For`` is now supported.
+
+    .. attribute:: protocol
+
+       The protocol used, either "http" or "https".  If ``HTTPServer.xheaders``
+       is set, will pass along the protocol used by a load balancer if
+       reported via an ``X-Scheme`` header.
+
+    .. attribute:: host
+
+       The requested hostname, usually taken from the ``Host`` header.
+
+    .. attribute:: arguments
+
+       GET/POST arguments are available in the arguments property, which
+       maps arguments names to lists of values (to support multiple values
+       for individual names). Names are of type `str`, while arguments
+       are byte strings.  Note that this is different from
+       `.RequestHandler.get_argument`, which returns argument values as
+       unicode strings.
+
+    .. attribute:: query_arguments
+
+       Same format as ``arguments``, but contains only arguments extracted
+       from the query string.
+
+       .. versionadded:: 3.2
+
+    .. attribute:: body_arguments
+
+       Same format as ``arguments``, but contains only arguments extracted
+       from the request body.
+
+       .. versionadded:: 3.2
+
+    .. attribute:: files
+
+       File uploads are available in the files property, which maps file
+       names to lists of `.HTTPFile`.
+
+    .. attribute:: connection
+
+       An HTTP request is attached to a single HTTP connection, which can
+       be accessed through the "connection" attribute. Since connections
+       are typically kept open in HTTP/1.1, multiple requests can be handled
+       sequentially on a single connection.
+
+    .. versionchanged:: 4.0
+       Moved from ``tornado.httpserver.HTTPRequest``.
+    """
+
+    path = None  # type: str
+    query = None  # type: str
+
+    # HACK: Used for stream_request_body
+    _body_future = None  # type: Future[None]
+
+    def __init__(
+        self,
+        method: Optional[str] = None,
+        uri: Optional[str] = None,
+        version: str = "HTTP/1.0",
+        headers: Optional[HTTPHeaders] = None,
+        body: Optional[bytes] = None,
+        host: Optional[str] = None,
+        files: Optional[Dict[str, List["HTTPFile"]]] = None,
+        connection: Optional["HTTPConnection"] = None,
+        start_line: Optional["RequestStartLine"] = None,
+        server_connection: Optional[object] = None,
+    ) -> None:
+        if start_line is not None:
+            method, uri, version = start_line
+        self.method = method
+        self.uri = uri
+        self.version = version
+        self.headers = headers or HTTPHeaders()
+        self.body = body or b""
+
+        # set remote IP and protocol
+        context = getattr(connection, "context", None)
+        self.remote_ip = getattr(context, "remote_ip", None)
+        self.protocol = getattr(context, "protocol", "http")
+
+        self.host = host or self.headers.get("Host") or "127.0.0.1"
+        self.host_name = split_host_and_port(self.host.lower())[0]
+        self.files = files or {}
+        self.connection = connection
+        self.server_connection = server_connection
+        self._start_time = time.time()
+        self._finish_time = None
+
+        if uri is not None:
+            self.path, sep, self.query = uri.partition("?")
+        self.arguments = parse_qs_bytes(self.query, keep_blank_values=True)
+        self.query_arguments = copy.deepcopy(self.arguments)
+        self.body_arguments = {}  # type: Dict[str, List[bytes]]
+
+    @property
+    def cookies(self) -> Dict[str, http.cookies.Morsel]:
+        """A dictionary of ``http.cookies.Morsel`` objects."""
+        if not hasattr(self, "_cookies"):
+            self._cookies = (
+                http.cookies.SimpleCookie()
+            )  # type: http.cookies.SimpleCookie
+            if "Cookie" in self.headers:
+                try:
+                    parsed = parse_cookie(self.headers["Cookie"])
+                except Exception:
+                    pass
+                else:
+                    for k, v in parsed.items():
+                        try:
+                            self._cookies[k] = v
+                        except Exception:
+                            # SimpleCookie imposes some restrictions on keys;
+                            # parse_cookie does not. Discard any cookies
+                            # with disallowed keys.
+                            pass
+        return self._cookies
+
+    def full_url(self) -> str:
+        """Reconstructs the full URL for this request."""
+        return self.protocol + "://" + self.host + self.uri  # type: ignore[operator]
+
+    def request_time(self) -> float:
+        """Returns the amount of time it took for this request to execute."""
+        if self._finish_time is None:
+            return time.time() - self._start_time
+        else:
+            return self._finish_time - self._start_time
+
+    def get_ssl_certificate(
+        self, binary_form: bool = False
+    ) -> Union[None, Dict, bytes]:
+        """Returns the client's SSL certificate, if any.
+
+        To use client certificates, the HTTPServer's
+        `ssl.SSLContext.verify_mode` field must be set, e.g.::
+
+            ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+            ssl_ctx.load_cert_chain("foo.crt", "foo.key")
+            ssl_ctx.load_verify_locations("cacerts.pem")
+            ssl_ctx.verify_mode = ssl.CERT_REQUIRED
+            server = HTTPServer(app, ssl_options=ssl_ctx)
+
+        By default, the return value is a dictionary (or None, if no
+        client certificate is present).  If ``binary_form`` is true, a
+        DER-encoded form of the certificate is returned instead.  See
+        SSLSocket.getpeercert() in the standard library for more
+        details.
+        http://docs.python.org/library/ssl.html#sslsocket-objects
+        """
+        try:
+            if self.connection is None:
+                return None
+            # TODO: add a method to HTTPConnection for this so it can work with HTTP/2
+            return self.connection.stream.socket.getpeercert(  # type: ignore
+                binary_form=binary_form
+            )
+        except SSLError:
+            return None
+
+    def _parse_body(self) -> None:
+        parse_body_arguments(
+            self.headers.get("Content-Type", ""),
+            self.body,
+            self.body_arguments,
+            self.files,
+            self.headers,
+        )
+
+        for k, v in self.body_arguments.items():
+            self.arguments.setdefault(k, []).extend(v)
+
+    def __repr__(self) -> str:
+        attrs = ("protocol", "host", "method", "uri", "version", "remote_ip")
+        args = ", ".join(["%s=%r" % (n, getattr(self, n)) for n in attrs])
+        return "%s(%s)" % (self.__class__.__name__, args)
+
+
+class HTTPInputError(Exception):
+    """Exception class for malformed HTTP requests or responses
+    from remote sources.
+
+    .. versionadded:: 4.0
+    """
+
+    pass
+
+
+class HTTPOutputError(Exception):
+    """Exception class for errors in HTTP output.
+
+    .. versionadded:: 4.0
+    """
+
+    pass
+
+
+class HTTPServerConnectionDelegate(object):
+    """Implement this interface to handle requests from `.HTTPServer`.
+
+    .. versionadded:: 4.0
+    """
+
+    def start_request(
+        self, server_conn: object, request_conn: "HTTPConnection"
+    ) -> "HTTPMessageDelegate":
+        """This method is called by the server when a new request has started.
+
+        :arg server_conn: is an opaque object representing the long-lived
+            (e.g. tcp-level) connection.
+        :arg request_conn: is a `.HTTPConnection` object for a single
+            request/response exchange.
+
+        This method should return a `.HTTPMessageDelegate`.
+        """
+        raise NotImplementedError()
+
+    def on_close(self, server_conn: object) -> None:
+        """This method is called when a connection has been closed.
+
+        :arg server_conn: is a server connection that has previously been
+            passed to ``start_request``.
+        """
+        pass
+
+
+class HTTPMessageDelegate(object):
+    """Implement this interface to handle an HTTP request or response.
+
+    .. versionadded:: 4.0
+    """
+
+    # TODO: genericize this class to avoid exposing the Union.
+    def headers_received(
+        self,
+        start_line: Union["RequestStartLine", "ResponseStartLine"],
+        headers: HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        """Called when the HTTP headers have been received and parsed.
+
+        :arg start_line: a `.RequestStartLine` or `.ResponseStartLine`
+            depending on whether this is a client or server message.
+        :arg headers: a `.HTTPHeaders` instance.
+
+        Some `.HTTPConnection` methods can only be called during
+        ``headers_received``.
+
+        May return a `.Future`; if it does the body will not be read
+        until it is done.
+        """
+        pass
+
+    def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
+        """Called when a chunk of data has been received.
+
+        May return a `.Future` for flow control.
+        """
+        pass
+
+    def finish(self) -> None:
+        """Called after the last chunk of data has been received."""
+        pass
+
+    def on_connection_close(self) -> None:
+        """Called if the connection is closed without finishing the request.
+
+        If ``headers_received`` is called, either ``finish`` or
+        ``on_connection_close`` will be called, but not both.
+        """
+        pass
+
+
+class HTTPConnection(object):
+    """Applications use this interface to write their responses.
+
+    .. versionadded:: 4.0
+    """
+
+    def write_headers(
+        self,
+        start_line: Union["RequestStartLine", "ResponseStartLine"],
+        headers: HTTPHeaders,
+        chunk: Optional[bytes] = None,
+    ) -> "Future[None]":
+        """Write an HTTP header block.
+
+        :arg start_line: a `.RequestStartLine` or `.ResponseStartLine`.
+        :arg headers: a `.HTTPHeaders` instance.
+        :arg chunk: the first (optional) chunk of data.  This is an optimization
+            so that small responses can be written in the same call as their
+            headers.
+
+        The ``version`` field of ``start_line`` is ignored.
+
+        Returns a future for flow control.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed.
+        """
+        raise NotImplementedError()
+
+    def write(self, chunk: bytes) -> "Future[None]":
+        """Writes a chunk of body data.
+
+        Returns a future for flow control.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed.
+        """
+        raise NotImplementedError()
+
+    def finish(self) -> None:
+        """Indicates that the last body data has been written."""
+        raise NotImplementedError()
+
+
+def url_concat(
+    url: str,
+    args: Union[
+        None, Dict[str, str], List[Tuple[str, str]], Tuple[Tuple[str, str], ...]
+    ],
+) -> str:
+    """Concatenate url and arguments regardless of whether
+    url has existing query parameters.
+
+    ``args`` may be either a dictionary or a list of key-value pairs
+    (the latter allows for multiple values with the same key.
+
+    >>> url_concat("http://example.com/foo", dict(c="d"))
+    'http://example.com/foo?c=d'
+    >>> url_concat("http://example.com/foo?a=b", dict(c="d"))
+    'http://example.com/foo?a=b&c=d'
+    >>> url_concat("http://example.com/foo?a=b", [("c", "d"), ("c", "d2")])
+    'http://example.com/foo?a=b&c=d&c=d2'
+    """
+    if args is None:
+        return url
+    parsed_url = urlparse(url)
+    if isinstance(args, dict):
+        parsed_query = parse_qsl(parsed_url.query, keep_blank_values=True)
+        parsed_query.extend(args.items())
+    elif isinstance(args, list) or isinstance(args, tuple):
+        parsed_query = parse_qsl(parsed_url.query, keep_blank_values=True)
+        parsed_query.extend(args)
+    else:
+        err = "'args' parameter should be dict, list or tuple. Not {0}".format(
+            type(args)
+        )
+        raise TypeError(err)
+    final_query = urlencode(parsed_query)
+    url = urlunparse(
+        (
+            parsed_url[0],
+            parsed_url[1],
+            parsed_url[2],
+            parsed_url[3],
+            final_query,
+            parsed_url[5],
+        )
+    )
+    return url
+
+
+class HTTPFile(ObjectDict):
+    """Represents a file uploaded via a form.
+
+    For backwards compatibility, its instance attributes are also
+    accessible as dictionary keys.
+
+    * ``filename``
+    * ``body``
+    * ``content_type``
+    """
+
+    filename: str
+    body: bytes
+    content_type: str
+
+
+def _parse_request_range(
+    range_header: str,
+) -> Optional[Tuple[Optional[int], Optional[int]]]:
+    """Parses a Range header.
+
+    Returns either ``None`` or tuple ``(start, end)``.
+    Note that while the HTTP headers use inclusive byte positions,
+    this method returns indexes suitable for use in slices.
+
+    >>> start, end = _parse_request_range("bytes=1-2")
+    >>> start, end
+    (1, 3)
+    >>> [0, 1, 2, 3, 4][start:end]
+    [1, 2]
+    >>> _parse_request_range("bytes=6-")
+    (6, None)
+    >>> _parse_request_range("bytes=-6")
+    (-6, None)
+    >>> _parse_request_range("bytes=-0")
+    (None, 0)
+    >>> _parse_request_range("bytes=")
+    (None, None)
+    >>> _parse_request_range("foo=42")
+    >>> _parse_request_range("bytes=1-2,6-10")
+
+    Note: only supports one range (ex, ``bytes=1-2,6-10`` is not allowed).
+
+    See [0] for the details of the range header.
+
+    [0]: http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p5-range-latest.html#byte.ranges
+    """
+    unit, _, value = range_header.partition("=")
+    unit, value = unit.strip(), value.strip()
+    if unit != "bytes":
+        return None
+    start_b, _, end_b = value.partition("-")
+    try:
+        start = _int_or_none(start_b)
+        end = _int_or_none(end_b)
+    except ValueError:
+        return None
+    if end is not None:
+        if start is None:
+            if end != 0:
+                start = -end
+                end = None
+        else:
+            end += 1
+    return (start, end)
+
+
+def _get_content_range(start: Optional[int], end: Optional[int], total: int) -> str:
+    """Returns a suitable Content-Range header:
+
+    >>> print(_get_content_range(None, 1, 4))
+    bytes 0-0/4
+    >>> print(_get_content_range(1, 3, 4))
+    bytes 1-2/4
+    >>> print(_get_content_range(None, None, 4))
+    bytes 0-3/4
+    """
+    start = start or 0
+    end = (end or total) - 1
+    return "bytes %s-%s/%s" % (start, end, total)
+
+
+def _int_or_none(val: str) -> Optional[int]:
+    val = val.strip()
+    if val == "":
+        return None
+    return int(val)
+
+
+def parse_body_arguments(
+    content_type: str,
+    body: bytes,
+    arguments: Dict[str, List[bytes]],
+    files: Dict[str, List[HTTPFile]],
+    headers: Optional[HTTPHeaders] = None,
+) -> None:
+    """Parses a form request body.
+
+    Supports ``application/x-www-form-urlencoded`` and
+    ``multipart/form-data``.  The ``content_type`` parameter should be
+    a string and ``body`` should be a byte string.  The ``arguments``
+    and ``files`` parameters are dictionaries that will be updated
+    with the parsed contents.
+    """
+    if content_type.startswith("application/x-www-form-urlencoded"):
+        if headers and "Content-Encoding" in headers:
+            gen_log.warning(
+                "Unsupported Content-Encoding: %s", headers["Content-Encoding"]
+            )
+            return
+        try:
+            # real charset decoding will happen in RequestHandler.decode_argument()
+            uri_arguments = parse_qs_bytes(body, keep_blank_values=True)
+        except Exception as e:
+            gen_log.warning("Invalid x-www-form-urlencoded body: %s", e)
+            uri_arguments = {}
+        for name, values in uri_arguments.items():
+            if values:
+                arguments.setdefault(name, []).extend(values)
+    elif content_type.startswith("multipart/form-data"):
+        if headers and "Content-Encoding" in headers:
+            gen_log.warning(
+                "Unsupported Content-Encoding: %s", headers["Content-Encoding"]
+            )
+            return
+        try:
+            fields = content_type.split(";")
+            for field in fields:
+                k, sep, v = field.strip().partition("=")
+                if k == "boundary" and v:
+                    parse_multipart_form_data(utf8(v), body, arguments, files)
+                    break
+            else:
+                raise ValueError("multipart boundary not found")
+        except Exception as e:
+            gen_log.warning("Invalid multipart/form-data: %s", e)
+
+
+def parse_multipart_form_data(
+    boundary: bytes,
+    data: bytes,
+    arguments: Dict[str, List[bytes]],
+    files: Dict[str, List[HTTPFile]],
+) -> None:
+    """Parses a ``multipart/form-data`` body.
+
+    The ``boundary`` and ``data`` parameters are both byte strings.
+    The dictionaries given in the arguments and files parameters
+    will be updated with the contents of the body.
+
+    .. versionchanged:: 5.1
+
+       Now recognizes non-ASCII filenames in RFC 2231/5987
+       (``filename*=``) format.
+    """
+    # The standard allows for the boundary to be quoted in the header,
+    # although it's rare (it happens at least for google app engine
+    # xmpp).  I think we're also supposed to handle backslash-escapes
+    # here but I'll save that until we see a client that uses them
+    # in the wild.
+    if boundary.startswith(b'"') and boundary.endswith(b'"'):
+        boundary = boundary[1:-1]
+    final_boundary_index = data.rfind(b"--" + boundary + b"--")
+    if final_boundary_index == -1:
+        gen_log.warning("Invalid multipart/form-data: no final boundary")
+        return
+    parts = data[:final_boundary_index].split(b"--" + boundary + b"\r\n")
+    for part in parts:
+        if not part:
+            continue
+        eoh = part.find(b"\r\n\r\n")
+        if eoh == -1:
+            gen_log.warning("multipart/form-data missing headers")
+            continue
+        headers = HTTPHeaders.parse(part[:eoh].decode("utf-8"))
+        disp_header = headers.get("Content-Disposition", "")
+        disposition, disp_params = _parse_header(disp_header)
+        if disposition != "form-data" or not part.endswith(b"\r\n"):
+            gen_log.warning("Invalid multipart/form-data")
+            continue
+        value = part[eoh + 4 : -2]
+        if not disp_params.get("name"):
+            gen_log.warning("multipart/form-data value missing name")
+            continue
+        name = disp_params["name"]
+        if disp_params.get("filename"):
+            ctype = headers.get("Content-Type", "application/unknown")
+            files.setdefault(name, []).append(
+                HTTPFile(
+                    filename=disp_params["filename"], body=value, content_type=ctype
+                )
+            )
+        else:
+            arguments.setdefault(name, []).append(value)
+
+
+def format_timestamp(
+    ts: Union[int, float, tuple, time.struct_time, datetime.datetime]
+) -> str:
+    """Formats a timestamp in the format used by HTTP.
+
+    The argument may be a numeric timestamp as returned by `time.time`,
+    a time tuple as returned by `time.gmtime`, or a `datetime.datetime`
+    object.
+
+    >>> format_timestamp(1359312200)
+    'Sun, 27 Jan 2013 18:43:20 GMT'
+    """
+    if isinstance(ts, (int, float)):
+        time_num = ts
+    elif isinstance(ts, (tuple, time.struct_time)):
+        time_num = calendar.timegm(ts)
+    elif isinstance(ts, datetime.datetime):
+        time_num = calendar.timegm(ts.utctimetuple())
+    else:
+        raise TypeError("unknown timestamp type: %r" % ts)
+    return email.utils.formatdate(time_num, usegmt=True)
+
+
+RequestStartLine = collections.namedtuple(
+    "RequestStartLine", ["method", "path", "version"]
+)
+
+
+_http_version_re = re.compile(r"^HTTP/1\.[0-9]$")
+
+
+def parse_request_start_line(line: str) -> RequestStartLine:
+    """Returns a (method, path, version) tuple for an HTTP 1.x request line.
+
+    The response is a `collections.namedtuple`.
+
+    >>> parse_request_start_line("GET /foo HTTP/1.1")
+    RequestStartLine(method='GET', path='/foo', version='HTTP/1.1')
+    """
+    try:
+        method, path, version = line.split(" ")
+    except ValueError:
+        # https://tools.ietf.org/html/rfc7230#section-3.1.1
+        # invalid request-line SHOULD respond with a 400 (Bad Request)
+        raise HTTPInputError("Malformed HTTP request line")
+    if not _http_version_re.match(version):
+        raise HTTPInputError(
+            "Malformed HTTP version in HTTP Request-Line: %r" % version
+        )
+    return RequestStartLine(method, path, version)
+
+
+ResponseStartLine = collections.namedtuple(
+    "ResponseStartLine", ["version", "code", "reason"]
+)
+
+
+_http_response_line_re = re.compile(r"(HTTP/1.[0-9]) ([0-9]+) ([^\r]*)")
+
+
+def parse_response_start_line(line: str) -> ResponseStartLine:
+    """Returns a (version, code, reason) tuple for an HTTP 1.x response line.
+
+    The response is a `collections.namedtuple`.
+
+    >>> parse_response_start_line("HTTP/1.1 200 OK")
+    ResponseStartLine(version='HTTP/1.1', code=200, reason='OK')
+    """
+    line = native_str(line)
+    match = _http_response_line_re.match(line)
+    if not match:
+        raise HTTPInputError("Error parsing response start line")
+    return ResponseStartLine(match.group(1), int(match.group(2)), match.group(3))
+
+
+# _parseparam and _parse_header are copied and modified from python2.7's cgi.py
+# The original 2.7 version of this code did not correctly support some
+# combinations of semicolons and double quotes.
+# It has also been modified to support valueless parameters as seen in
+# websocket extension negotiations, and to support non-ascii values in
+# RFC 2231/5987 format.
+
+
+def _parseparam(s: str) -> Generator[str, None, None]:
+    while s[:1] == ";":
+        s = s[1:]
+        end = s.find(";")
+        while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
+            end = s.find(";", end + 1)
+        if end < 0:
+            end = len(s)
+        f = s[:end]
+        yield f.strip()
+        s = s[end:]
+
+
+def _parse_header(line: str) -> Tuple[str, Dict[str, str]]:
+    r"""Parse a Content-type like header.
+
+    Return the main content-type and a dictionary of options.
+
+    >>> d = "form-data; foo=\"b\\\\a\\\"r\"; file*=utf-8''T%C3%A4st"
+    >>> ct, d = _parse_header(d)
+    >>> ct
+    'form-data'
+    >>> d['file'] == r'T\u00e4st'.encode('ascii').decode('unicode_escape')
+    True
+    >>> d['foo']
+    'b\\a"r'
+    """
+    parts = _parseparam(";" + line)
+    key = next(parts)
+    # decode_params treats first argument special, but we already stripped key
+    params = [("Dummy", "value")]
+    for p in parts:
+        i = p.find("=")
+        if i >= 0:
+            name = p[:i].strip().lower()
+            value = p[i + 1 :].strip()
+            params.append((name, native_str(value)))
+    decoded_params = email.utils.decode_params(params)
+    decoded_params.pop(0)  # get rid of the dummy again
+    pdict = {}
+    for name, decoded_value in decoded_params:
+        value = email.utils.collapse_rfc2231_value(decoded_value)
+        if len(value) >= 2 and value[0] == '"' and value[-1] == '"':
+            value = value[1:-1]
+        pdict[name] = value
+    return key, pdict
+
+
+def _encode_header(key: str, pdict: Dict[str, str]) -> str:
+    """Inverse of _parse_header.
+
+    >>> _encode_header('permessage-deflate',
+    ...     {'client_max_window_bits': 15, 'client_no_context_takeover': None})
+    'permessage-deflate; client_max_window_bits=15; client_no_context_takeover'
+    """
+    if not pdict:
+        return key
+    out = [key]
+    # Sort the parameters just to make it easy to test.
+    for k, v in sorted(pdict.items()):
+        if v is None:
+            out.append(k)
+        else:
+            # TODO: quote if necessary.
+            out.append("%s=%s" % (k, v))
+    return "; ".join(out)
+
+
+def encode_username_password(
+    username: Union[str, bytes], password: Union[str, bytes]
+) -> bytes:
+    """Encodes a username/password pair in the format used by HTTP auth.
+
+    The return value is a byte string in the form ``username:password``.
+
+    .. versionadded:: 5.1
+    """
+    if isinstance(username, unicode_type):
+        username = unicodedata.normalize("NFC", username)
+    if isinstance(password, unicode_type):
+        password = unicodedata.normalize("NFC", password)
+    return utf8(username) + b":" + utf8(password)
+
+
+def doctests():
+    # type: () -> unittest.TestSuite
+    import doctest
+
+    return doctest.DocTestSuite()
+
+
+_netloc_re = re.compile(r"^(.+):(\d+)$")
+
+
+def split_host_and_port(netloc: str) -> Tuple[str, Optional[int]]:
+    """Returns ``(host, port)`` tuple from ``netloc``.
+
+    Returned ``port`` will be ``None`` if not present.
+
+    .. versionadded:: 4.1
+    """
+    match = _netloc_re.match(netloc)
+    if match:
+        host = match.group(1)
+        port = int(match.group(2))  # type: Optional[int]
+    else:
+        host = netloc
+        port = None
+    return (host, port)
+
+
+def qs_to_qsl(qs: Dict[str, List[AnyStr]]) -> Iterable[Tuple[str, AnyStr]]:
+    """Generator converting a result of ``parse_qs`` back to name-value pairs.
+
+    .. versionadded:: 5.0
+    """
+    for k, vs in qs.items():
+        for v in vs:
+            yield (k, v)
+
+
+_OctalPatt = re.compile(r"\\[0-3][0-7][0-7]")
+_QuotePatt = re.compile(r"[\\].")
+_nulljoin = "".join
+
+
+def _unquote_cookie(s: str) -> str:
+    """Handle double quotes and escaping in cookie values.
+
+    This method is copied verbatim from the Python 3.5 standard
+    library (http.cookies._unquote) so we don't have to depend on
+    non-public interfaces.
+    """
+    # If there aren't any doublequotes,
+    # then there can't be any special characters.  See RFC 2109.
+    if s is None or len(s) < 2:
+        return s
+    if s[0] != '"' or s[-1] != '"':
+        return s
+
+    # We have to assume that we must decode this string.
+    # Down to work.
+
+    # Remove the "s
+    s = s[1:-1]
+
+    # Check for special sequences.  Examples:
+    #    \012 --> \n
+    #    \"   --> "
+    #
+    i = 0
+    n = len(s)
+    res = []
+    while 0 <= i < n:
+        o_match = _OctalPatt.search(s, i)
+        q_match = _QuotePatt.search(s, i)
+        if not o_match and not q_match:  # Neither matched
+            res.append(s[i:])
+            break
+        # else:
+        j = k = -1
+        if o_match:
+            j = o_match.start(0)
+        if q_match:
+            k = q_match.start(0)
+        if q_match and (not o_match or k < j):  # QuotePatt matched
+            res.append(s[i:k])
+            res.append(s[k + 1])
+            i = k + 2
+        else:  # OctalPatt matched
+            res.append(s[i:j])
+            res.append(chr(int(s[j + 1 : j + 4], 8)))
+            i = j + 4
+    return _nulljoin(res)
+
+
+def parse_cookie(cookie: str) -> Dict[str, str]:
+    """Parse a ``Cookie`` HTTP header into a dict of name/value pairs.
+
+    This function attempts to mimic browser cookie parsing behavior;
+    it specifically does not follow any of the cookie-related RFCs
+    (because browsers don't either).
+
+    The algorithm used is identical to that used by Django version 1.9.10.
+
+    .. versionadded:: 4.4.2
+    """
+    cookiedict = {}
+    for chunk in cookie.split(str(";")):
+        if str("=") in chunk:
+            key, val = chunk.split(str("="), 1)
+        else:
+            # Assume an empty name per
+            # https://bugzilla.mozilla.org/show_bug.cgi?id=169091
+            key, val = str(""), chunk
+        key, val = key.strip(), val.strip()
+        if key or val:
+            # unquote using Python's algorithm.
+            cookiedict[key] = _unquote_cookie(val)
+    return cookiedict
diff --git a/venv/lib/python3.9/site-packages/tornado/ioloop.py b/venv/lib/python3.9/site-packages/tornado/ioloop.py
new file mode 100644
index 00000000..bcdcca09
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/ioloop.py
@@ -0,0 +1,960 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""An I/O event loop for non-blocking sockets.
+
+In Tornado 6.0, `.IOLoop` is a wrapper around the `asyncio` event loop, with a
+slightly different interface. The `.IOLoop` interface is now provided primarily
+for backwards compatibility; new code should generally use the `asyncio` event
+loop interface directly. The `IOLoop.current` class method provides the
+`IOLoop` instance corresponding to the running `asyncio` event loop.
+
+"""
+
+import asyncio
+import concurrent.futures
+import datetime
+import functools
+import numbers
+import os
+import sys
+import time
+import math
+import random
+import warnings
+from inspect import isawaitable
+
+from tornado.concurrent import (
+    Future,
+    is_future,
+    chain_future,
+    future_set_exc_info,
+    future_add_done_callback,
+)
+from tornado.log import app_log
+from tornado.util import Configurable, TimeoutError, import_object
+
+import typing
+from typing import Union, Any, Type, Optional, Callable, TypeVar, Tuple, Awaitable
+
+if typing.TYPE_CHECKING:
+    from typing import Dict, List  # noqa: F401
+
+    from typing_extensions import Protocol
+else:
+    Protocol = object
+
+
+class _Selectable(Protocol):
+    def fileno(self) -> int:
+        pass
+
+    def close(self) -> None:
+        pass
+
+
+_T = TypeVar("_T")
+_S = TypeVar("_S", bound=_Selectable)
+
+
+class IOLoop(Configurable):
+    """An I/O event loop.
+
+    As of Tornado 6.0, `IOLoop` is a wrapper around the `asyncio` event loop.
+
+    Example usage for a simple TCP server:
+
+    .. testcode::
+
+        import asyncio
+        import errno
+        import functools
+        import socket
+
+        import tornado
+        from tornado.iostream import IOStream
+
+        async def handle_connection(connection, address):
+            stream = IOStream(connection)
+            message = await stream.read_until_close()
+            print("message from client:", message.decode().strip())
+
+        def connection_ready(sock, fd, events):
+            while True:
+                try:
+                    connection, address = sock.accept()
+                except BlockingIOError:
+                    return
+                connection.setblocking(0)
+                io_loop = tornado.ioloop.IOLoop.current()
+                io_loop.spawn_callback(handle_connection, connection, address)
+
+        async def main():
+            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            sock.setblocking(0)
+            sock.bind(("", 8888))
+            sock.listen(128)
+
+            io_loop = tornado.ioloop.IOLoop.current()
+            callback = functools.partial(connection_ready, sock)
+            io_loop.add_handler(sock.fileno(), callback, io_loop.READ)
+            await asyncio.Event().wait()
+
+        if __name__ == "__main__":
+            asyncio.run(main())
+
+    .. testoutput::
+       :hide:
+
+    Most applications should not attempt to construct an `IOLoop` directly,
+    and instead initialize the `asyncio` event loop and use `IOLoop.current()`.
+    In some cases, such as in test frameworks when initializing an `IOLoop`
+    to be run in a secondary thread, it may be appropriate to construct
+    an `IOLoop` with ``IOLoop(make_current=False)``.
+
+    In general, an `IOLoop` cannot survive a fork or be shared across processes
+    in any way. When multiple processes are being used, each process should
+    create its own `IOLoop`, which also implies that any objects which depend on
+    the `IOLoop` (such as `.AsyncHTTPClient`) must also be created in the child
+    processes. As a guideline, anything that starts processes (including the
+    `tornado.process` and `multiprocessing` modules) should do so as early as
+    possible, ideally the first thing the application does after loading its
+    configuration, and *before* any calls to `.IOLoop.start` or `asyncio.run`.
+
+    .. versionchanged:: 4.2
+       Added the ``make_current`` keyword argument to the `IOLoop`
+       constructor.
+
+    .. versionchanged:: 5.0
+
+       Uses the `asyncio` event loop by default. The ``IOLoop.configure`` method
+       cannot be used on Python 3 except to redundantly specify the `asyncio`
+       event loop.
+
+    .. versionchanged:: 6.3
+       ``make_current=True`` is now the default when creating an IOLoop -
+       previously the default was to make the event loop current if there wasn't
+       already a current one.
+    """
+
+    # These constants were originally based on constants from the epoll module.
+    NONE = 0
+    READ = 0x001
+    WRITE = 0x004
+    ERROR = 0x018
+
+    # In Python 3, _ioloop_for_asyncio maps from asyncio loops to IOLoops.
+    _ioloop_for_asyncio = dict()  # type: Dict[asyncio.AbstractEventLoop, IOLoop]
+
+    @classmethod
+    def configure(
+        cls, impl: "Union[None, str, Type[Configurable]]", **kwargs: Any
+    ) -> None:
+        from tornado.platform.asyncio import BaseAsyncIOLoop
+
+        if isinstance(impl, str):
+            impl = import_object(impl)
+        if isinstance(impl, type) and not issubclass(impl, BaseAsyncIOLoop):
+            raise RuntimeError("only AsyncIOLoop is allowed when asyncio is available")
+        super(IOLoop, cls).configure(impl, **kwargs)
+
+    @staticmethod
+    def instance() -> "IOLoop":
+        """Deprecated alias for `IOLoop.current()`.
+
+        .. versionchanged:: 5.0
+
+           Previously, this method returned a global singleton
+           `IOLoop`, in contrast with the per-thread `IOLoop` returned
+           by `current()`. In nearly all cases the two were the same
+           (when they differed, it was generally used from non-Tornado
+           threads to communicate back to the main thread's `IOLoop`).
+           This distinction is not present in `asyncio`, so in order
+           to facilitate integration with that package `instance()`
+           was changed to be an alias to `current()`. Applications
+           using the cross-thread communications aspect of
+           `instance()` should instead set their own global variable
+           to point to the `IOLoop` they want to use.
+
+        .. deprecated:: 5.0
+        """
+        return IOLoop.current()
+
+    def install(self) -> None:
+        """Deprecated alias for `make_current()`.
+
+        .. versionchanged:: 5.0
+
+           Previously, this method would set this `IOLoop` as the
+           global singleton used by `IOLoop.instance()`. Now that
+           `instance()` is an alias for `current()`, `install()`
+           is an alias for `make_current()`.
+
+        .. deprecated:: 5.0
+        """
+        self.make_current()
+
+    @staticmethod
+    def clear_instance() -> None:
+        """Deprecated alias for `clear_current()`.
+
+        .. versionchanged:: 5.0
+
+           Previously, this method would clear the `IOLoop` used as
+           the global singleton by `IOLoop.instance()`. Now that
+           `instance()` is an alias for `current()`,
+           `clear_instance()` is an alias for `clear_current()`.
+
+        .. deprecated:: 5.0
+
+        """
+        IOLoop.clear_current()
+
+    @typing.overload
+    @staticmethod
+    def current() -> "IOLoop":
+        pass
+
+    @typing.overload
+    @staticmethod
+    def current(instance: bool = True) -> Optional["IOLoop"]:  # noqa: F811
+        pass
+
+    @staticmethod
+    def current(instance: bool = True) -> Optional["IOLoop"]:  # noqa: F811
+        """Returns the current thread's `IOLoop`.
+
+        If an `IOLoop` is currently running or has been marked as
+        current by `make_current`, returns that instance.  If there is
+        no current `IOLoop` and ``instance`` is true, creates one.
+
+        .. versionchanged:: 4.1
+           Added ``instance`` argument to control the fallback to
+           `IOLoop.instance()`.
+        .. versionchanged:: 5.0
+           On Python 3, control of the current `IOLoop` is delegated
+           to `asyncio`, with this and other methods as pass-through accessors.
+           The ``instance`` argument now controls whether an `IOLoop`
+           is created automatically when there is none, instead of
+           whether we fall back to `IOLoop.instance()` (which is now
+           an alias for this method). ``instance=False`` is deprecated,
+           since even if we do not create an `IOLoop`, this method
+           may initialize the asyncio loop.
+
+        .. deprecated:: 6.2
+           It is deprecated to call ``IOLoop.current()`` when no `asyncio`
+           event loop is running.
+        """
+        try:
+            loop = asyncio.get_event_loop()
+        except RuntimeError:
+            if not instance:
+                return None
+            # Create a new asyncio event loop for this thread.
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+
+        try:
+            return IOLoop._ioloop_for_asyncio[loop]
+        except KeyError:
+            if instance:
+                from tornado.platform.asyncio import AsyncIOMainLoop
+
+                current = AsyncIOMainLoop()  # type: Optional[IOLoop]
+            else:
+                current = None
+        return current
+
+    def make_current(self) -> None:
+        """Makes this the `IOLoop` for the current thread.
+
+        An `IOLoop` automatically becomes current for its thread
+        when it is started, but it is sometimes useful to call
+        `make_current` explicitly before starting the `IOLoop`,
+        so that code run at startup time can find the right
+        instance.
+
+        .. versionchanged:: 4.1
+           An `IOLoop` created while there is no current `IOLoop`
+           will automatically become current.
+
+        .. versionchanged:: 5.0
+           This method also sets the current `asyncio` event loop.
+
+        .. deprecated:: 6.2
+           Setting and clearing the current event loop through Tornado is
+           deprecated. Use ``asyncio.set_event_loop`` instead if you need this.
+        """
+        warnings.warn(
+            "make_current is deprecated; start the event loop first",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        self._make_current()
+
+    def _make_current(self) -> None:
+        # The asyncio event loops override this method.
+        raise NotImplementedError()
+
+    @staticmethod
+    def clear_current() -> None:
+        """Clears the `IOLoop` for the current thread.
+
+        Intended primarily for use by test frameworks in between tests.
+
+        .. versionchanged:: 5.0
+           This method also clears the current `asyncio` event loop.
+        .. deprecated:: 6.2
+        """
+        warnings.warn(
+            "clear_current is deprecated",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        IOLoop._clear_current()
+
+    @staticmethod
+    def _clear_current() -> None:
+        old = IOLoop.current(instance=False)
+        if old is not None:
+            old._clear_current_hook()
+
+    def _clear_current_hook(self) -> None:
+        """Instance method called when an IOLoop ceases to be current.
+
+        May be overridden by subclasses as a counterpart to make_current.
+        """
+        pass
+
+    @classmethod
+    def configurable_base(cls) -> Type[Configurable]:
+        return IOLoop
+
+    @classmethod
+    def configurable_default(cls) -> Type[Configurable]:
+        from tornado.platform.asyncio import AsyncIOLoop
+
+        return AsyncIOLoop
+
+    def initialize(self, make_current: bool = True) -> None:
+        if make_current:
+            self._make_current()
+
+    def close(self, all_fds: bool = False) -> None:
+        """Closes the `IOLoop`, freeing any resources used.
+
+        If ``all_fds`` is true, all file descriptors registered on the
+        IOLoop will be closed (not just the ones created by the
+        `IOLoop` itself).
+
+        Many applications will only use a single `IOLoop` that runs for the
+        entire lifetime of the process.  In that case closing the `IOLoop`
+        is not necessary since everything will be cleaned up when the
+        process exits.  `IOLoop.close` is provided mainly for scenarios
+        such as unit tests, which create and destroy a large number of
+        ``IOLoops``.
+
+        An `IOLoop` must be completely stopped before it can be closed.  This
+        means that `IOLoop.stop()` must be called *and* `IOLoop.start()` must
+        be allowed to return before attempting to call `IOLoop.close()`.
+        Therefore the call to `close` will usually appear just after
+        the call to `start` rather than near the call to `stop`.
+
+        .. versionchanged:: 3.1
+           If the `IOLoop` implementation supports non-integer objects
+           for "file descriptors", those objects will have their
+           ``close`` method when ``all_fds`` is true.
+        """
+        raise NotImplementedError()
+
+    @typing.overload
+    def add_handler(
+        self, fd: int, handler: Callable[[int, int], None], events: int
+    ) -> None:
+        pass
+
+    @typing.overload  # noqa: F811
+    def add_handler(
+        self, fd: _S, handler: Callable[[_S, int], None], events: int
+    ) -> None:
+        pass
+
+    def add_handler(  # noqa: F811
+        self, fd: Union[int, _Selectable], handler: Callable[..., None], events: int
+    ) -> None:
+        """Registers the given handler to receive the given events for ``fd``.
+
+        The ``fd`` argument may either be an integer file descriptor or
+        a file-like object with a ``fileno()`` and ``close()`` method.
+
+        The ``events`` argument is a bitwise or of the constants
+        ``IOLoop.READ``, ``IOLoop.WRITE``, and ``IOLoop.ERROR``.
+
+        When an event occurs, ``handler(fd, events)`` will be run.
+
+        .. versionchanged:: 4.0
+           Added the ability to pass file-like objects in addition to
+           raw file descriptors.
+        """
+        raise NotImplementedError()
+
+    def update_handler(self, fd: Union[int, _Selectable], events: int) -> None:
+        """Changes the events we listen for ``fd``.
+
+        .. versionchanged:: 4.0
+           Added the ability to pass file-like objects in addition to
+           raw file descriptors.
+        """
+        raise NotImplementedError()
+
+    def remove_handler(self, fd: Union[int, _Selectable]) -> None:
+        """Stop listening for events on ``fd``.
+
+        .. versionchanged:: 4.0
+           Added the ability to pass file-like objects in addition to
+           raw file descriptors.
+        """
+        raise NotImplementedError()
+
+    def start(self) -> None:
+        """Starts the I/O loop.
+
+        The loop will run until one of the callbacks calls `stop()`, which
+        will make the loop stop after the current event iteration completes.
+        """
+        raise NotImplementedError()
+
+    def stop(self) -> None:
+        """Stop the I/O loop.
+
+        If the event loop is not currently running, the next call to `start()`
+        will return immediately.
+
+        Note that even after `stop` has been called, the `IOLoop` is not
+        completely stopped until `IOLoop.start` has also returned.
+        Some work that was scheduled before the call to `stop` may still
+        be run before the `IOLoop` shuts down.
+        """
+        raise NotImplementedError()
+
+    def run_sync(self, func: Callable, timeout: Optional[float] = None) -> Any:
+        """Starts the `IOLoop`, runs the given function, and stops the loop.
+
+        The function must return either an awaitable object or
+        ``None``. If the function returns an awaitable object, the
+        `IOLoop` will run until the awaitable is resolved (and
+        `run_sync()` will return the awaitable's result). If it raises
+        an exception, the `IOLoop` will stop and the exception will be
+        re-raised to the caller.
+
+        The keyword-only argument ``timeout`` may be used to set
+        a maximum duration for the function.  If the timeout expires,
+        a `asyncio.TimeoutError` is raised.
+
+        This method is useful to allow asynchronous calls in a
+        ``main()`` function::
+
+            async def main():
+                # do stuff...
+
+            if __name__ == '__main__':
+                IOLoop.current().run_sync(main)
+
+        .. versionchanged:: 4.3
+           Returning a non-``None``, non-awaitable value is now an error.
+
+        .. versionchanged:: 5.0
+           If a timeout occurs, the ``func`` coroutine will be cancelled.
+
+        .. versionchanged:: 6.2
+           ``tornado.util.TimeoutError`` is now an alias to ``asyncio.TimeoutError``.
+        """
+        future_cell = [None]  # type: List[Optional[Future]]
+
+        def run() -> None:
+            try:
+                result = func()
+                if result is not None:
+                    from tornado.gen import convert_yielded
+
+                    result = convert_yielded(result)
+            except Exception:
+                fut = Future()  # type: Future[Any]
+                future_cell[0] = fut
+                future_set_exc_info(fut, sys.exc_info())
+            else:
+                if is_future(result):
+                    future_cell[0] = result
+                else:
+                    fut = Future()
+                    future_cell[0] = fut
+                    fut.set_result(result)
+            assert future_cell[0] is not None
+            self.add_future(future_cell[0], lambda future: self.stop())
+
+        self.add_callback(run)
+        if timeout is not None:
+
+            def timeout_callback() -> None:
+                # If we can cancel the future, do so and wait on it. If not,
+                # Just stop the loop and return with the task still pending.
+                # (If we neither cancel nor wait for the task, a warning
+                # will be logged).
+                assert future_cell[0] is not None
+                if not future_cell[0].cancel():
+                    self.stop()
+
+            timeout_handle = self.add_timeout(self.time() + timeout, timeout_callback)
+        self.start()
+        if timeout is not None:
+            self.remove_timeout(timeout_handle)
+        assert future_cell[0] is not None
+        if future_cell[0].cancelled() or not future_cell[0].done():
+            raise TimeoutError("Operation timed out after %s seconds" % timeout)
+        return future_cell[0].result()
+
+    def time(self) -> float:
+        """Returns the current time according to the `IOLoop`'s clock.
+
+        The return value is a floating-point number relative to an
+        unspecified time in the past.
+
+        Historically, the IOLoop could be customized to use e.g.
+        `time.monotonic` instead of `time.time`, but this is not
+        currently supported and so this method is equivalent to
+        `time.time`.
+
+        """
+        return time.time()
+
+    def add_timeout(
+        self,
+        deadline: Union[float, datetime.timedelta],
+        callback: Callable,
+        *args: Any,
+        **kwargs: Any
+    ) -> object:
+        """Runs the ``callback`` at the time ``deadline`` from the I/O loop.
+
+        Returns an opaque handle that may be passed to
+        `remove_timeout` to cancel.
+
+        ``deadline`` may be a number denoting a time (on the same
+        scale as `IOLoop.time`, normally `time.time`), or a
+        `datetime.timedelta` object for a deadline relative to the
+        current time.  Since Tornado 4.0, `call_later` is a more
+        convenient alternative for the relative case since it does not
+        require a timedelta object.
+
+        Note that it is not safe to call `add_timeout` from other threads.
+        Instead, you must use `add_callback` to transfer control to the
+        `IOLoop`'s thread, and then call `add_timeout` from there.
+
+        Subclasses of IOLoop must implement either `add_timeout` or
+        `call_at`; the default implementations of each will call
+        the other.  `call_at` is usually easier to implement, but
+        subclasses that wish to maintain compatibility with Tornado
+        versions prior to 4.0 must use `add_timeout` instead.
+
+        .. versionchanged:: 4.0
+           Now passes through ``*args`` and ``**kwargs`` to the callback.
+        """
+        if isinstance(deadline, numbers.Real):
+            return self.call_at(deadline, callback, *args, **kwargs)
+        elif isinstance(deadline, datetime.timedelta):
+            return self.call_at(
+                self.time() + deadline.total_seconds(), callback, *args, **kwargs
+            )
+        else:
+            raise TypeError("Unsupported deadline %r" % deadline)
+
+    def call_later(
+        self, delay: float, callback: Callable, *args: Any, **kwargs: Any
+    ) -> object:
+        """Runs the ``callback`` after ``delay`` seconds have passed.
+
+        Returns an opaque handle that may be passed to `remove_timeout`
+        to cancel.  Note that unlike the `asyncio` method of the same
+        name, the returned object does not have a ``cancel()`` method.
+
+        See `add_timeout` for comments on thread-safety and subclassing.
+
+        .. versionadded:: 4.0
+        """
+        return self.call_at(self.time() + delay, callback, *args, **kwargs)
+
+    def call_at(
+        self, when: float, callback: Callable, *args: Any, **kwargs: Any
+    ) -> object:
+        """Runs the ``callback`` at the absolute time designated by ``when``.
+
+        ``when`` must be a number using the same reference point as
+        `IOLoop.time`.
+
+        Returns an opaque handle that may be passed to `remove_timeout`
+        to cancel.  Note that unlike the `asyncio` method of the same
+        name, the returned object does not have a ``cancel()`` method.
+
+        See `add_timeout` for comments on thread-safety and subclassing.
+
+        .. versionadded:: 4.0
+        """
+        return self.add_timeout(when, callback, *args, **kwargs)
+
+    def remove_timeout(self, timeout: object) -> None:
+        """Cancels a pending timeout.
+
+        The argument is a handle as returned by `add_timeout`.  It is
+        safe to call `remove_timeout` even if the callback has already
+        been run.
+        """
+        raise NotImplementedError()
+
+    def add_callback(self, callback: Callable, *args: Any, **kwargs: Any) -> None:
+        """Calls the given callback on the next I/O loop iteration.
+
+        It is safe to call this method from any thread at any time,
+        except from a signal handler.  Note that this is the **only**
+        method in `IOLoop` that makes this thread-safety guarantee; all
+        other interaction with the `IOLoop` must be done from that
+        `IOLoop`'s thread.  `add_callback()` may be used to transfer
+        control from other threads to the `IOLoop`'s thread.
+
+        To add a callback from a signal handler, see
+        `add_callback_from_signal`.
+        """
+        raise NotImplementedError()
+
+    def add_callback_from_signal(
+        self, callback: Callable, *args: Any, **kwargs: Any
+    ) -> None:
+        """Calls the given callback on the next I/O loop iteration.
+
+        Safe for use from a Python signal handler; should not be used
+        otherwise.
+        """
+        raise NotImplementedError()
+
+    def spawn_callback(self, callback: Callable, *args: Any, **kwargs: Any) -> None:
+        """Calls the given callback on the next IOLoop iteration.
+
+        As of Tornado 6.0, this method is equivalent to `add_callback`.
+
+        .. versionadded:: 4.0
+        """
+        self.add_callback(callback, *args, **kwargs)
+
+    def add_future(
+        self,
+        future: "Union[Future[_T], concurrent.futures.Future[_T]]",
+        callback: Callable[["Future[_T]"], None],
+    ) -> None:
+        """Schedules a callback on the ``IOLoop`` when the given
+        `.Future` is finished.
+
+        The callback is invoked with one argument, the
+        `.Future`.
+
+        This method only accepts `.Future` objects and not other
+        awaitables (unlike most of Tornado where the two are
+        interchangeable).
+        """
+        if isinstance(future, Future):
+            # Note that we specifically do not want the inline behavior of
+            # tornado.concurrent.future_add_done_callback. We always want
+            # this callback scheduled on the next IOLoop iteration (which
+            # asyncio.Future always does).
+            #
+            # Wrap the callback in self._run_callback so we control
+            # the error logging (i.e. it goes to tornado.log.app_log
+            # instead of asyncio's log).
+            future.add_done_callback(
+                lambda f: self._run_callback(functools.partial(callback, future))
+            )
+        else:
+            assert is_future(future)
+            # For concurrent futures, we use self.add_callback, so
+            # it's fine if future_add_done_callback inlines that call.
+            future_add_done_callback(
+                future, lambda f: self.add_callback(callback, future)
+            )
+
+    def run_in_executor(
+        self,
+        executor: Optional[concurrent.futures.Executor],
+        func: Callable[..., _T],
+        *args: Any
+    ) -> Awaitable[_T]:
+        """Runs a function in a ``concurrent.futures.Executor``. If
+        ``executor`` is ``None``, the IO loop's default executor will be used.
+
+        Use `functools.partial` to pass keyword arguments to ``func``.
+
+        .. versionadded:: 5.0
+        """
+        if executor is None:
+            if not hasattr(self, "_executor"):
+                from tornado.process import cpu_count
+
+                self._executor = concurrent.futures.ThreadPoolExecutor(
+                    max_workers=(cpu_count() * 5)
+                )  # type: concurrent.futures.Executor
+            executor = self._executor
+        c_future = executor.submit(func, *args)
+        # Concurrent Futures are not usable with await. Wrap this in a
+        # Tornado Future instead, using self.add_future for thread-safety.
+        t_future = Future()  # type: Future[_T]
+        self.add_future(c_future, lambda f: chain_future(f, t_future))
+        return t_future
+
+    def set_default_executor(self, executor: concurrent.futures.Executor) -> None:
+        """Sets the default executor to use with :meth:`run_in_executor`.
+
+        .. versionadded:: 5.0
+        """
+        self._executor = executor
+
+    def _run_callback(self, callback: Callable[[], Any]) -> None:
+        """Runs a callback with error handling.
+
+        .. versionchanged:: 6.0
+
+           CancelledErrors are no longer logged.
+        """
+        try:
+            ret = callback()
+            if ret is not None:
+                from tornado import gen
+
+                # Functions that return Futures typically swallow all
+                # exceptions and store them in the Future.  If a Future
+                # makes it out to the IOLoop, ensure its exception (if any)
+                # gets logged too.
+                try:
+                    ret = gen.convert_yielded(ret)
+                except gen.BadYieldError:
+                    # It's not unusual for add_callback to be used with
+                    # methods returning a non-None and non-yieldable
+                    # result, which should just be ignored.
+                    pass
+                else:
+                    self.add_future(ret, self._discard_future_result)
+        except asyncio.CancelledError:
+            pass
+        except Exception:
+            app_log.error("Exception in callback %r", callback, exc_info=True)
+
+    def _discard_future_result(self, future: Future) -> None:
+        """Avoid unhandled-exception warnings from spawned coroutines."""
+        future.result()
+
+    def split_fd(
+        self, fd: Union[int, _Selectable]
+    ) -> Tuple[int, Union[int, _Selectable]]:
+        # """Returns an (fd, obj) pair from an ``fd`` parameter.
+
+        # We accept both raw file descriptors and file-like objects as
+        # input to `add_handler` and related methods.  When a file-like
+        # object is passed, we must retain the object itself so we can
+        # close it correctly when the `IOLoop` shuts down, but the
+        # poller interfaces favor file descriptors (they will accept
+        # file-like objects and call ``fileno()`` for you, but they
+        # always return the descriptor itself).
+
+        # This method is provided for use by `IOLoop` subclasses and should
+        # not generally be used by application code.
+
+        # .. versionadded:: 4.0
+        # """
+        if isinstance(fd, int):
+            return fd, fd
+        return fd.fileno(), fd
+
+    def close_fd(self, fd: Union[int, _Selectable]) -> None:
+        # """Utility method to close an ``fd``.
+
+        # If ``fd`` is a file-like object, we close it directly; otherwise
+        # we use `os.close`.
+
+        # This method is provided for use by `IOLoop` subclasses (in
+        # implementations of ``IOLoop.close(all_fds=True)`` and should
+        # not generally be used by application code.
+
+        # .. versionadded:: 4.0
+        # """
+        try:
+            if isinstance(fd, int):
+                os.close(fd)
+            else:
+                fd.close()
+        except OSError:
+            pass
+
+
+class _Timeout(object):
+    """An IOLoop timeout, a UNIX timestamp and a callback"""
+
+    # Reduce memory overhead when there are lots of pending callbacks
+    __slots__ = ["deadline", "callback", "tdeadline"]
+
+    def __init__(
+        self, deadline: float, callback: Callable[[], None], io_loop: IOLoop
+    ) -> None:
+        if not isinstance(deadline, numbers.Real):
+            raise TypeError("Unsupported deadline %r" % deadline)
+        self.deadline = deadline
+        self.callback = callback
+        self.tdeadline = (
+            deadline,
+            next(io_loop._timeout_counter),
+        )  # type: Tuple[float, int]
+
+    # Comparison methods to sort by deadline, with object id as a tiebreaker
+    # to guarantee a consistent ordering.  The heapq module uses __le__
+    # in python2.5, and __lt__ in 2.6+ (sort() and most other comparisons
+    # use __lt__).
+    def __lt__(self, other: "_Timeout") -> bool:
+        return self.tdeadline < other.tdeadline
+
+    def __le__(self, other: "_Timeout") -> bool:
+        return self.tdeadline <= other.tdeadline
+
+
+class PeriodicCallback(object):
+    """Schedules the given callback to be called periodically.
+
+    The callback is called every ``callback_time`` milliseconds when
+    ``callback_time`` is a float. Note that the timeout is given in
+    milliseconds, while most other time-related functions in Tornado use
+    seconds. ``callback_time`` may alternatively be given as a
+    `datetime.timedelta` object.
+
+    If ``jitter`` is specified, each callback time will be randomly selected
+    within a window of ``jitter * callback_time`` milliseconds.
+    Jitter can be used to reduce alignment of events with similar periods.
+    A jitter of 0.1 means allowing a 10% variation in callback time.
+    The window is centered on ``callback_time`` so the total number of calls
+    within a given interval should not be significantly affected by adding
+    jitter.
+
+    If the callback runs for longer than ``callback_time`` milliseconds,
+    subsequent invocations will be skipped to get back on schedule.
+
+    `start` must be called after the `PeriodicCallback` is created.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. versionchanged:: 5.1
+       The ``jitter`` argument is added.
+
+    .. versionchanged:: 6.2
+       If the ``callback`` argument is a coroutine, and a callback runs for
+       longer than ``callback_time``, subsequent invocations will be skipped.
+       Previously this was only true for regular functions, not coroutines,
+       which were "fire-and-forget" for `PeriodicCallback`.
+
+       The ``callback_time`` argument now accepts `datetime.timedelta` objects,
+       in addition to the previous numeric milliseconds.
+    """
+
+    def __init__(
+        self,
+        callback: Callable[[], Optional[Awaitable]],
+        callback_time: Union[datetime.timedelta, float],
+        jitter: float = 0,
+    ) -> None:
+        self.callback = callback
+        if isinstance(callback_time, datetime.timedelta):
+            self.callback_time = callback_time / datetime.timedelta(milliseconds=1)
+        else:
+            if callback_time <= 0:
+                raise ValueError("Periodic callback must have a positive callback_time")
+            self.callback_time = callback_time
+        self.jitter = jitter
+        self._running = False
+        self._timeout = None  # type: object
+
+    def start(self) -> None:
+        """Starts the timer."""
+        # Looking up the IOLoop here allows to first instantiate the
+        # PeriodicCallback in another thread, then start it using
+        # IOLoop.add_callback().
+        self.io_loop = IOLoop.current()
+        self._running = True
+        self._next_timeout = self.io_loop.time()
+        self._schedule_next()
+
+    def stop(self) -> None:
+        """Stops the timer."""
+        self._running = False
+        if self._timeout is not None:
+            self.io_loop.remove_timeout(self._timeout)
+            self._timeout = None
+
+    def is_running(self) -> bool:
+        """Returns ``True`` if this `.PeriodicCallback` has been started.
+
+        .. versionadded:: 4.1
+        """
+        return self._running
+
+    async def _run(self) -> None:
+        if not self._running:
+            return
+        try:
+            val = self.callback()
+            if val is not None and isawaitable(val):
+                await val
+        except Exception:
+            app_log.error("Exception in callback %r", self.callback, exc_info=True)
+        finally:
+            self._schedule_next()
+
+    def _schedule_next(self) -> None:
+        if self._running:
+            self._update_next(self.io_loop.time())
+            self._timeout = self.io_loop.add_timeout(self._next_timeout, self._run)
+
+    def _update_next(self, current_time: float) -> None:
+        callback_time_sec = self.callback_time / 1000.0
+        if self.jitter:
+            # apply jitter fraction
+            callback_time_sec *= 1 + (self.jitter * (random.random() - 0.5))
+        if self._next_timeout <= current_time:
+            # The period should be measured from the start of one call
+            # to the start of the next. If one call takes too long,
+            # skip cycles to get back to a multiple of the original
+            # schedule.
+            self._next_timeout += (
+                math.floor((current_time - self._next_timeout) / callback_time_sec) + 1
+            ) * callback_time_sec
+        else:
+            # If the clock moved backwards, ensure we advance the next
+            # timeout instead of recomputing the same value again.
+            # This may result in long gaps between callbacks if the
+            # clock jumps backwards by a lot, but the far more common
+            # scenario is a small NTP adjustment that should just be
+            # ignored.
+            #
+            # Note that on some systems if time.time() runs slower
+            # than time.monotonic() (most common on windows), we
+            # effectively experience a small backwards time jump on
+            # every iteration because PeriodicCallback uses
+            # time.time() while asyncio schedules callbacks using
+            # time.monotonic().
+            # https://github.com/tornadoweb/tornado/issues/2333
+            self._next_timeout += callback_time_sec
diff --git a/venv/lib/python3.9/site-packages/tornado/iostream.py b/venv/lib/python3.9/site-packages/tornado/iostream.py
new file mode 100644
index 00000000..a408be59
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/iostream.py
@@ -0,0 +1,1654 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Utility classes to write to and read from non-blocking files and sockets.
+
+Contents:
+
+* `BaseIOStream`: Generic interface for reading and writing.
+* `IOStream`: Implementation of BaseIOStream using non-blocking sockets.
+* `SSLIOStream`: SSL-aware version of IOStream.
+* `PipeIOStream`: Pipe-based IOStream implementation.
+"""
+
+import asyncio
+import collections
+import errno
+import io
+import numbers
+import os
+import socket
+import ssl
+import sys
+import re
+
+from tornado.concurrent import Future, future_set_result_unless_cancelled
+from tornado import ioloop
+from tornado.log import gen_log
+from tornado.netutil import ssl_wrap_socket, _client_ssl_defaults, _server_ssl_defaults
+from tornado.util import errno_from_exception
+
+import typing
+from typing import (
+    Union,
+    Optional,
+    Awaitable,
+    Callable,
+    Pattern,
+    Any,
+    Dict,
+    TypeVar,
+    Tuple,
+)
+from types import TracebackType
+
+if typing.TYPE_CHECKING:
+    from typing import Deque, List, Type  # noqa: F401
+
+_IOStreamType = TypeVar("_IOStreamType", bound="IOStream")
+
+# These errnos indicate that a connection has been abruptly terminated.
+# They should be caught and handled less noisily than other errors.
+_ERRNO_CONNRESET = (errno.ECONNRESET, errno.ECONNABORTED, errno.EPIPE, errno.ETIMEDOUT)
+
+if hasattr(errno, "WSAECONNRESET"):
+    _ERRNO_CONNRESET += (  # type: ignore
+        errno.WSAECONNRESET,  # type: ignore
+        errno.WSAECONNABORTED,  # type: ignore
+        errno.WSAETIMEDOUT,  # type: ignore
+    )
+
+if sys.platform == "darwin":
+    # OSX appears to have a race condition that causes send(2) to return
+    # EPROTOTYPE if called while a socket is being torn down:
+    # http://erickt.github.io/blog/2014/11/19/adventures-in-debugging-a-potential-osx-kernel-bug/
+    # Since the socket is being closed anyway, treat this as an ECONNRESET
+    # instead of an unexpected error.
+    _ERRNO_CONNRESET += (errno.EPROTOTYPE,)  # type: ignore
+
+_WINDOWS = sys.platform.startswith("win")
+
+
+class StreamClosedError(IOError):
+    """Exception raised by `IOStream` methods when the stream is closed.
+
+    Note that the close callback is scheduled to run *after* other
+    callbacks on the stream (to allow for buffered data to be processed),
+    so you may see this error before you see the close callback.
+
+    The ``real_error`` attribute contains the underlying error that caused
+    the stream to close (if any).
+
+    .. versionchanged:: 4.3
+       Added the ``real_error`` attribute.
+    """
+
+    def __init__(self, real_error: Optional[BaseException] = None) -> None:
+        super().__init__("Stream is closed")
+        self.real_error = real_error
+
+
+class UnsatisfiableReadError(Exception):
+    """Exception raised when a read cannot be satisfied.
+
+    Raised by ``read_until`` and ``read_until_regex`` with a ``max_bytes``
+    argument.
+    """
+
+    pass
+
+
+class StreamBufferFullError(Exception):
+    """Exception raised by `IOStream` methods when the buffer is full."""
+
+
+class _StreamBuffer(object):
+    """
+    A specialized buffer that tries to avoid copies when large pieces
+    of data are encountered.
+    """
+
+    def __init__(self) -> None:
+        # A sequence of (False, bytearray) and (True, memoryview) objects
+        self._buffers = (
+            collections.deque()
+        )  # type: Deque[Tuple[bool, Union[bytearray, memoryview]]]
+        # Position in the first buffer
+        self._first_pos = 0
+        self._size = 0
+
+    def __len__(self) -> int:
+        return self._size
+
+    # Data above this size will be appended separately instead
+    # of extending an existing bytearray
+    _large_buf_threshold = 2048
+
+    def append(self, data: Union[bytes, bytearray, memoryview]) -> None:
+        """
+        Append the given piece of data (should be a buffer-compatible object).
+        """
+        size = len(data)
+        if size > self._large_buf_threshold:
+            if not isinstance(data, memoryview):
+                data = memoryview(data)
+            self._buffers.append((True, data))
+        elif size > 0:
+            if self._buffers:
+                is_memview, b = self._buffers[-1]
+                new_buf = is_memview or len(b) >= self._large_buf_threshold
+            else:
+                new_buf = True
+            if new_buf:
+                self._buffers.append((False, bytearray(data)))
+            else:
+                b += data  # type: ignore
+
+        self._size += size
+
+    def peek(self, size: int) -> memoryview:
+        """
+        Get a view over at most ``size`` bytes (possibly fewer) at the
+        current buffer position.
+        """
+        assert size > 0
+        try:
+            is_memview, b = self._buffers[0]
+        except IndexError:
+            return memoryview(b"")
+
+        pos = self._first_pos
+        if is_memview:
+            return typing.cast(memoryview, b[pos : pos + size])
+        else:
+            return memoryview(b)[pos : pos + size]
+
+    def advance(self, size: int) -> None:
+        """
+        Advance the current buffer position by ``size`` bytes.
+        """
+        assert 0 < size <= self._size
+        self._size -= size
+        pos = self._first_pos
+
+        buffers = self._buffers
+        while buffers and size > 0:
+            is_large, b = buffers[0]
+            b_remain = len(b) - size - pos
+            if b_remain <= 0:
+                buffers.popleft()
+                size -= len(b) - pos
+                pos = 0
+            elif is_large:
+                pos += size
+                size = 0
+            else:
+                pos += size
+                del typing.cast(bytearray, b)[:pos]
+                pos = 0
+                size = 0
+
+        assert size == 0
+        self._first_pos = pos
+
+
+class BaseIOStream(object):
+    """A utility class to write to and read from a non-blocking file or socket.
+
+    We support a non-blocking ``write()`` and a family of ``read_*()``
+    methods. When the operation completes, the ``Awaitable`` will resolve
+    with the data read (or ``None`` for ``write()``). All outstanding
+    ``Awaitables`` will resolve with a `StreamClosedError` when the
+    stream is closed; `.BaseIOStream.set_close_callback` can also be used
+    to be notified of a closed stream.
+
+    When a stream is closed due to an error, the IOStream's ``error``
+    attribute contains the exception object.
+
+    Subclasses must implement `fileno`, `close_fd`, `write_to_fd`,
+    `read_from_fd`, and optionally `get_fd_error`.
+
+    """
+
+    def __init__(
+        self,
+        max_buffer_size: Optional[int] = None,
+        read_chunk_size: Optional[int] = None,
+        max_write_buffer_size: Optional[int] = None,
+    ) -> None:
+        """`BaseIOStream` constructor.
+
+        :arg max_buffer_size: Maximum amount of incoming data to buffer;
+            defaults to 100MB.
+        :arg read_chunk_size: Amount of data to read at one time from the
+            underlying transport; defaults to 64KB.
+        :arg max_write_buffer_size: Amount of outgoing data to buffer;
+            defaults to unlimited.
+
+        .. versionchanged:: 4.0
+           Add the ``max_write_buffer_size`` parameter.  Changed default
+           ``read_chunk_size`` to 64KB.
+        .. versionchanged:: 5.0
+           The ``io_loop`` argument (deprecated since version 4.1) has been
+           removed.
+        """
+        self.io_loop = ioloop.IOLoop.current()
+        self.max_buffer_size = max_buffer_size or 104857600
+        # A chunk size that is too close to max_buffer_size can cause
+        # spurious failures.
+        self.read_chunk_size = min(read_chunk_size or 65536, self.max_buffer_size // 2)
+        self.max_write_buffer_size = max_write_buffer_size
+        self.error = None  # type: Optional[BaseException]
+        self._read_buffer = bytearray()
+        self._read_buffer_size = 0
+        self._user_read_buffer = False
+        self._after_user_read_buffer = None  # type: Optional[bytearray]
+        self._write_buffer = _StreamBuffer()
+        self._total_write_index = 0
+        self._total_write_done_index = 0
+        self._read_delimiter = None  # type: Optional[bytes]
+        self._read_regex = None  # type: Optional[Pattern]
+        self._read_max_bytes = None  # type: Optional[int]
+        self._read_bytes = None  # type: Optional[int]
+        self._read_partial = False
+        self._read_until_close = False
+        self._read_future = None  # type: Optional[Future]
+        self._write_futures = (
+            collections.deque()
+        )  # type: Deque[Tuple[int, Future[None]]]
+        self._close_callback = None  # type: Optional[Callable[[], None]]
+        self._connect_future = None  # type: Optional[Future[IOStream]]
+        # _ssl_connect_future should be defined in SSLIOStream
+        # but it's here so we can clean it up in _signal_closed
+        # TODO: refactor that so subclasses can add additional futures
+        # to be cancelled.
+        self._ssl_connect_future = None  # type: Optional[Future[SSLIOStream]]
+        self._connecting = False
+        self._state = None  # type: Optional[int]
+        self._closed = False
+
+    def fileno(self) -> Union[int, ioloop._Selectable]:
+        """Returns the file descriptor for this stream."""
+        raise NotImplementedError()
+
+    def close_fd(self) -> None:
+        """Closes the file underlying this stream.
+
+        ``close_fd`` is called by `BaseIOStream` and should not be called
+        elsewhere; other users should call `close` instead.
+        """
+        raise NotImplementedError()
+
+    def write_to_fd(self, data: memoryview) -> int:
+        """Attempts to write ``data`` to the underlying file.
+
+        Returns the number of bytes written.
+        """
+        raise NotImplementedError()
+
+    def read_from_fd(self, buf: Union[bytearray, memoryview]) -> Optional[int]:
+        """Attempts to read from the underlying file.
+
+        Reads up to ``len(buf)`` bytes, storing them in the buffer.
+        Returns the number of bytes read. Returns None if there was
+        nothing to read (the socket returned `~errno.EWOULDBLOCK` or
+        equivalent), and zero on EOF.
+
+        .. versionchanged:: 5.0
+
+           Interface redesigned to take a buffer and return a number
+           of bytes instead of a freshly-allocated object.
+        """
+        raise NotImplementedError()
+
+    def get_fd_error(self) -> Optional[Exception]:
+        """Returns information about any error on the underlying file.
+
+        This method is called after the `.IOLoop` has signaled an error on the
+        file descriptor, and should return an Exception (such as `socket.error`
+        with additional information, or None if no such information is
+        available.
+        """
+        return None
+
+    def read_until_regex(
+        self, regex: bytes, max_bytes: Optional[int] = None
+    ) -> Awaitable[bytes]:
+        """Asynchronously read until we have matched the given regex.
+
+        The result includes the data that matches the regex and anything
+        that came before it.
+
+        If ``max_bytes`` is not None, the connection will be closed
+        if more than ``max_bytes`` bytes have been read and the regex is
+        not satisfied.
+
+        .. versionchanged:: 4.0
+            Added the ``max_bytes`` argument.  The ``callback`` argument is
+            now optional and a `.Future` will be returned if it is omitted.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+        """
+        future = self._start_read()
+        self._read_regex = re.compile(regex)
+        self._read_max_bytes = max_bytes
+        try:
+            self._try_inline_read()
+        except UnsatisfiableReadError as e:
+            # Handle this the same way as in _handle_events.
+            gen_log.info("Unsatisfiable read, closing connection: %s" % e)
+            self.close(exc_info=e)
+            return future
+        except:
+            # Ensure that the future doesn't log an error because its
+            # failure was never examined.
+            future.add_done_callback(lambda f: f.exception())
+            raise
+        return future
+
+    def read_until(
+        self, delimiter: bytes, max_bytes: Optional[int] = None
+    ) -> Awaitable[bytes]:
+        """Asynchronously read until we have found the given delimiter.
+
+        The result includes all the data read including the delimiter.
+
+        If ``max_bytes`` is not None, the connection will be closed
+        if more than ``max_bytes`` bytes have been read and the delimiter
+        is not found.
+
+        .. versionchanged:: 4.0
+            Added the ``max_bytes`` argument.  The ``callback`` argument is
+            now optional and a `.Future` will be returned if it is omitted.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+        """
+        future = self._start_read()
+        self._read_delimiter = delimiter
+        self._read_max_bytes = max_bytes
+        try:
+            self._try_inline_read()
+        except UnsatisfiableReadError as e:
+            # Handle this the same way as in _handle_events.
+            gen_log.info("Unsatisfiable read, closing connection: %s" % e)
+            self.close(exc_info=e)
+            return future
+        except:
+            future.add_done_callback(lambda f: f.exception())
+            raise
+        return future
+
+    def read_bytes(self, num_bytes: int, partial: bool = False) -> Awaitable[bytes]:
+        """Asynchronously read a number of bytes.
+
+        If ``partial`` is true, data is returned as soon as we have
+        any bytes to return (but never more than ``num_bytes``)
+
+        .. versionchanged:: 4.0
+            Added the ``partial`` argument.  The callback argument is now
+            optional and a `.Future` will be returned if it is omitted.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` and ``streaming_callback`` arguments have
+           been removed. Use the returned `.Future` (and
+           ``partial=True`` for ``streaming_callback``) instead.
+
+        """
+        future = self._start_read()
+        assert isinstance(num_bytes, numbers.Integral)
+        self._read_bytes = num_bytes
+        self._read_partial = partial
+        try:
+            self._try_inline_read()
+        except:
+            future.add_done_callback(lambda f: f.exception())
+            raise
+        return future
+
+    def read_into(self, buf: bytearray, partial: bool = False) -> Awaitable[int]:
+        """Asynchronously read a number of bytes.
+
+        ``buf`` must be a writable buffer into which data will be read.
+
+        If ``partial`` is true, the callback is run as soon as any bytes
+        have been read.  Otherwise, it is run when the ``buf`` has been
+        entirely filled with read data.
+
+        .. versionadded:: 5.0
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+        """
+        future = self._start_read()
+
+        # First copy data already in read buffer
+        available_bytes = self._read_buffer_size
+        n = len(buf)
+        if available_bytes >= n:
+            buf[:] = memoryview(self._read_buffer)[:n]
+            del self._read_buffer[:n]
+            self._after_user_read_buffer = self._read_buffer
+        elif available_bytes > 0:
+            buf[:available_bytes] = memoryview(self._read_buffer)[:]
+
+        # Set up the supplied buffer as our temporary read buffer.
+        # The original (if it had any data remaining) has been
+        # saved for later.
+        self._user_read_buffer = True
+        self._read_buffer = buf
+        self._read_buffer_size = available_bytes
+        self._read_bytes = n
+        self._read_partial = partial
+
+        try:
+            self._try_inline_read()
+        except:
+            future.add_done_callback(lambda f: f.exception())
+            raise
+        return future
+
+    def read_until_close(self) -> Awaitable[bytes]:
+        """Asynchronously reads all data from the socket until it is closed.
+
+        This will buffer all available data until ``max_buffer_size``
+        is reached. If flow control or cancellation are desired, use a
+        loop with `read_bytes(partial=True) <.read_bytes>` instead.
+
+        .. versionchanged:: 4.0
+            The callback argument is now optional and a `.Future` will
+            be returned if it is omitted.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` and ``streaming_callback`` arguments have
+           been removed. Use the returned `.Future` (and `read_bytes`
+           with ``partial=True`` for ``streaming_callback``) instead.
+
+        """
+        future = self._start_read()
+        if self.closed():
+            self._finish_read(self._read_buffer_size)
+            return future
+        self._read_until_close = True
+        try:
+            self._try_inline_read()
+        except:
+            future.add_done_callback(lambda f: f.exception())
+            raise
+        return future
+
+    def write(self, data: Union[bytes, memoryview]) -> "Future[None]":
+        """Asynchronously write the given data to this stream.
+
+        This method returns a `.Future` that resolves (with a result
+        of ``None``) when the write has been completed.
+
+        The ``data`` argument may be of type `bytes` or `memoryview`.
+
+        .. versionchanged:: 4.0
+            Now returns a `.Future` if no callback is given.
+
+        .. versionchanged:: 4.5
+            Added support for `memoryview` arguments.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+        """
+        self._check_closed()
+        if data:
+            if isinstance(data, memoryview):
+                # Make sure that ``len(data) == data.nbytes``
+                data = memoryview(data).cast("B")
+            if (
+                self.max_write_buffer_size is not None
+                and len(self._write_buffer) + len(data) > self.max_write_buffer_size
+            ):
+                raise StreamBufferFullError("Reached maximum write buffer size")
+            self._write_buffer.append(data)
+            self._total_write_index += len(data)
+        future = Future()  # type: Future[None]
+        future.add_done_callback(lambda f: f.exception())
+        self._write_futures.append((self._total_write_index, future))
+        if not self._connecting:
+            self._handle_write()
+            if self._write_buffer:
+                self._add_io_state(self.io_loop.WRITE)
+            self._maybe_add_error_listener()
+        return future
+
+    def set_close_callback(self, callback: Optional[Callable[[], None]]) -> None:
+        """Call the given callback when the stream is closed.
+
+        This mostly is not necessary for applications that use the
+        `.Future` interface; all outstanding ``Futures`` will resolve
+        with a `StreamClosedError` when the stream is closed. However,
+        it is still useful as a way to signal that the stream has been
+        closed while no other read or write is in progress.
+
+        Unlike other callback-based interfaces, ``set_close_callback``
+        was not removed in Tornado 6.0.
+        """
+        self._close_callback = callback
+        self._maybe_add_error_listener()
+
+    def close(
+        self,
+        exc_info: Union[
+            None,
+            bool,
+            BaseException,
+            Tuple[
+                "Optional[Type[BaseException]]",
+                Optional[BaseException],
+                Optional[TracebackType],
+            ],
+        ] = False,
+    ) -> None:
+        """Close this stream.
+
+        If ``exc_info`` is true, set the ``error`` attribute to the current
+        exception from `sys.exc_info` (or if ``exc_info`` is a tuple,
+        use that instead of `sys.exc_info`).
+        """
+        if not self.closed():
+            if exc_info:
+                if isinstance(exc_info, tuple):
+                    self.error = exc_info[1]
+                elif isinstance(exc_info, BaseException):
+                    self.error = exc_info
+                else:
+                    exc_info = sys.exc_info()
+                    if any(exc_info):
+                        self.error = exc_info[1]
+            if self._read_until_close:
+                self._read_until_close = False
+                self._finish_read(self._read_buffer_size)
+            elif self._read_future is not None:
+                # resolve reads that are pending and ready to complete
+                try:
+                    pos = self._find_read_pos()
+                except UnsatisfiableReadError:
+                    pass
+                else:
+                    if pos is not None:
+                        self._read_from_buffer(pos)
+            if self._state is not None:
+                self.io_loop.remove_handler(self.fileno())
+                self._state = None
+            self.close_fd()
+            self._closed = True
+        self._signal_closed()
+
+    def _signal_closed(self) -> None:
+        futures = []  # type: List[Future]
+        if self._read_future is not None:
+            futures.append(self._read_future)
+            self._read_future = None
+        futures += [future for _, future in self._write_futures]
+        self._write_futures.clear()
+        if self._connect_future is not None:
+            futures.append(self._connect_future)
+            self._connect_future = None
+        for future in futures:
+            if not future.done():
+                future.set_exception(StreamClosedError(real_error=self.error))
+            # Reference the exception to silence warnings. Annoyingly,
+            # this raises if the future was cancelled, but just
+            # returns any other error.
+            try:
+                future.exception()
+            except asyncio.CancelledError:
+                pass
+        if self._ssl_connect_future is not None:
+            # _ssl_connect_future expects to see the real exception (typically
+            # an ssl.SSLError), not just StreamClosedError.
+            if not self._ssl_connect_future.done():
+                if self.error is not None:
+                    self._ssl_connect_future.set_exception(self.error)
+                else:
+                    self._ssl_connect_future.set_exception(StreamClosedError())
+            self._ssl_connect_future.exception()
+            self._ssl_connect_future = None
+        if self._close_callback is not None:
+            cb = self._close_callback
+            self._close_callback = None
+            self.io_loop.add_callback(cb)
+        # Clear the buffers so they can be cleared immediately even
+        # if the IOStream object is kept alive by a reference cycle.
+        # TODO: Clear the read buffer too; it currently breaks some tests.
+        self._write_buffer = None  # type: ignore
+
+    def reading(self) -> bool:
+        """Returns ``True`` if we are currently reading from the stream."""
+        return self._read_future is not None
+
+    def writing(self) -> bool:
+        """Returns ``True`` if we are currently writing to the stream."""
+        return bool(self._write_buffer)
+
+    def closed(self) -> bool:
+        """Returns ``True`` if the stream has been closed."""
+        return self._closed
+
+    def set_nodelay(self, value: bool) -> None:
+        """Sets the no-delay flag for this stream.
+
+        By default, data written to TCP streams may be held for a time
+        to make the most efficient use of bandwidth (according to
+        Nagle's algorithm).  The no-delay flag requests that data be
+        written as soon as possible, even if doing so would consume
+        additional bandwidth.
+
+        This flag is currently defined only for TCP-based ``IOStreams``.
+
+        .. versionadded:: 3.1
+        """
+        pass
+
+    def _handle_connect(self) -> None:
+        raise NotImplementedError()
+
+    def _handle_events(self, fd: Union[int, ioloop._Selectable], events: int) -> None:
+        if self.closed():
+            gen_log.warning("Got events for closed stream %s", fd)
+            return
+        try:
+            if self._connecting:
+                # Most IOLoops will report a write failed connect
+                # with the WRITE event, but SelectIOLoop reports a
+                # READ as well so we must check for connecting before
+                # either.
+                self._handle_connect()
+            if self.closed():
+                return
+            if events & self.io_loop.READ:
+                self._handle_read()
+            if self.closed():
+                return
+            if events & self.io_loop.WRITE:
+                self._handle_write()
+            if self.closed():
+                return
+            if events & self.io_loop.ERROR:
+                self.error = self.get_fd_error()
+                # We may have queued up a user callback in _handle_read or
+                # _handle_write, so don't close the IOStream until those
+                # callbacks have had a chance to run.
+                self.io_loop.add_callback(self.close)
+                return
+            state = self.io_loop.ERROR
+            if self.reading():
+                state |= self.io_loop.READ
+            if self.writing():
+                state |= self.io_loop.WRITE
+            if state == self.io_loop.ERROR and self._read_buffer_size == 0:
+                # If the connection is idle, listen for reads too so
+                # we can tell if the connection is closed.  If there is
+                # data in the read buffer we won't run the close callback
+                # yet anyway, so we don't need to listen in this case.
+                state |= self.io_loop.READ
+            if state != self._state:
+                assert (
+                    self._state is not None
+                ), "shouldn't happen: _handle_events without self._state"
+                self._state = state
+                self.io_loop.update_handler(self.fileno(), self._state)
+        except UnsatisfiableReadError as e:
+            gen_log.info("Unsatisfiable read, closing connection: %s" % e)
+            self.close(exc_info=e)
+        except Exception as e:
+            gen_log.error("Uncaught exception, closing connection.", exc_info=True)
+            self.close(exc_info=e)
+            raise
+
+    def _read_to_buffer_loop(self) -> Optional[int]:
+        # This method is called from _handle_read and _try_inline_read.
+        if self._read_bytes is not None:
+            target_bytes = self._read_bytes  # type: Optional[int]
+        elif self._read_max_bytes is not None:
+            target_bytes = self._read_max_bytes
+        elif self.reading():
+            # For read_until without max_bytes, or
+            # read_until_close, read as much as we can before
+            # scanning for the delimiter.
+            target_bytes = None
+        else:
+            target_bytes = 0
+        next_find_pos = 0
+        while not self.closed():
+            # Read from the socket until we get EWOULDBLOCK or equivalent.
+            # SSL sockets do some internal buffering, and if the data is
+            # sitting in the SSL object's buffer select() and friends
+            # can't see it; the only way to find out if it's there is to
+            # try to read it.
+            if self._read_to_buffer() == 0:
+                break
+
+            # If we've read all the bytes we can use, break out of
+            # this loop.
+
+            # If we've reached target_bytes, we know we're done.
+            if target_bytes is not None and self._read_buffer_size >= target_bytes:
+                break
+
+            # Otherwise, we need to call the more expensive find_read_pos.
+            # It's inefficient to do this on every read, so instead
+            # do it on the first read and whenever the read buffer
+            # size has doubled.
+            if self._read_buffer_size >= next_find_pos:
+                pos = self._find_read_pos()
+                if pos is not None:
+                    return pos
+                next_find_pos = self._read_buffer_size * 2
+        return self._find_read_pos()
+
+    def _handle_read(self) -> None:
+        try:
+            pos = self._read_to_buffer_loop()
+        except UnsatisfiableReadError:
+            raise
+        except asyncio.CancelledError:
+            raise
+        except Exception as e:
+            gen_log.warning("error on read: %s" % e)
+            self.close(exc_info=e)
+            return
+        if pos is not None:
+            self._read_from_buffer(pos)
+
+    def _start_read(self) -> Future:
+        if self._read_future is not None:
+            # It is an error to start a read while a prior read is unresolved.
+            # However, if the prior read is unresolved because the stream was
+            # closed without satisfying it, it's better to raise
+            # StreamClosedError instead of AssertionError. In particular, this
+            # situation occurs in harmless situations in http1connection.py and
+            # an AssertionError would be logged noisily.
+            #
+            # On the other hand, it is legal to start a new read while the
+            # stream is closed, in case the read can be satisfied from the
+            # read buffer. So we only want to check the closed status of the
+            # stream if we need to decide what kind of error to raise for
+            # "already reading".
+            #
+            # These conditions have proven difficult to test; we have no
+            # unittests that reliably verify this behavior so be careful
+            # when making changes here. See #2651 and #2719.
+            self._check_closed()
+            assert self._read_future is None, "Already reading"
+        self._read_future = Future()
+        return self._read_future
+
+    def _finish_read(self, size: int) -> None:
+        if self._user_read_buffer:
+            self._read_buffer = self._after_user_read_buffer or bytearray()
+            self._after_user_read_buffer = None
+            self._read_buffer_size = len(self._read_buffer)
+            self._user_read_buffer = False
+            result = size  # type: Union[int, bytes]
+        else:
+            result = self._consume(size)
+        if self._read_future is not None:
+            future = self._read_future
+            self._read_future = None
+            future_set_result_unless_cancelled(future, result)
+        self._maybe_add_error_listener()
+
+    def _try_inline_read(self) -> None:
+        """Attempt to complete the current read operation from buffered data.
+
+        If the read can be completed without blocking, schedules the
+        read callback on the next IOLoop iteration; otherwise starts
+        listening for reads on the socket.
+        """
+        # See if we've already got the data from a previous read
+        pos = self._find_read_pos()
+        if pos is not None:
+            self._read_from_buffer(pos)
+            return
+        self._check_closed()
+        pos = self._read_to_buffer_loop()
+        if pos is not None:
+            self._read_from_buffer(pos)
+            return
+        # We couldn't satisfy the read inline, so make sure we're
+        # listening for new data unless the stream is closed.
+        if not self.closed():
+            self._add_io_state(ioloop.IOLoop.READ)
+
+    def _read_to_buffer(self) -> Optional[int]:
+        """Reads from the socket and appends the result to the read buffer.
+
+        Returns the number of bytes read.  Returns 0 if there is nothing
+        to read (i.e. the read returns EWOULDBLOCK or equivalent).  On
+        error closes the socket and raises an exception.
+        """
+        try:
+            while True:
+                try:
+                    if self._user_read_buffer:
+                        buf = memoryview(self._read_buffer)[
+                            self._read_buffer_size :
+                        ]  # type: Union[memoryview, bytearray]
+                    else:
+                        buf = bytearray(self.read_chunk_size)
+                    bytes_read = self.read_from_fd(buf)
+                except (socket.error, IOError, OSError) as e:
+                    # ssl.SSLError is a subclass of socket.error
+                    if self._is_connreset(e):
+                        # Treat ECONNRESET as a connection close rather than
+                        # an error to minimize log spam  (the exception will
+                        # be available on self.error for apps that care).
+                        self.close(exc_info=e)
+                        return None
+                    self.close(exc_info=e)
+                    raise
+                break
+            if bytes_read is None:
+                return 0
+            elif bytes_read == 0:
+                self.close()
+                return 0
+            if not self._user_read_buffer:
+                self._read_buffer += memoryview(buf)[:bytes_read]
+            self._read_buffer_size += bytes_read
+        finally:
+            # Break the reference to buf so we don't waste a chunk's worth of
+            # memory in case an exception hangs on to our stack frame.
+            del buf
+        if self._read_buffer_size > self.max_buffer_size:
+            gen_log.error("Reached maximum read buffer size")
+            self.close()
+            raise StreamBufferFullError("Reached maximum read buffer size")
+        return bytes_read
+
+    def _read_from_buffer(self, pos: int) -> None:
+        """Attempts to complete the currently-pending read from the buffer.
+
+        The argument is either a position in the read buffer or None,
+        as returned by _find_read_pos.
+        """
+        self._read_bytes = self._read_delimiter = self._read_regex = None
+        self._read_partial = False
+        self._finish_read(pos)
+
+    def _find_read_pos(self) -> Optional[int]:
+        """Attempts to find a position in the read buffer that satisfies
+        the currently-pending read.
+
+        Returns a position in the buffer if the current read can be satisfied,
+        or None if it cannot.
+        """
+        if self._read_bytes is not None and (
+            self._read_buffer_size >= self._read_bytes
+            or (self._read_partial and self._read_buffer_size > 0)
+        ):
+            num_bytes = min(self._read_bytes, self._read_buffer_size)
+            return num_bytes
+        elif self._read_delimiter is not None:
+            # Multi-byte delimiters (e.g. '\r\n') may straddle two
+            # chunks in the read buffer, so we can't easily find them
+            # without collapsing the buffer.  However, since protocols
+            # using delimited reads (as opposed to reads of a known
+            # length) tend to be "line" oriented, the delimiter is likely
+            # to be in the first few chunks.  Merge the buffer gradually
+            # since large merges are relatively expensive and get undone in
+            # _consume().
+            if self._read_buffer:
+                loc = self._read_buffer.find(self._read_delimiter)
+                if loc != -1:
+                    delimiter_len = len(self._read_delimiter)
+                    self._check_max_bytes(self._read_delimiter, loc + delimiter_len)
+                    return loc + delimiter_len
+                self._check_max_bytes(self._read_delimiter, self._read_buffer_size)
+        elif self._read_regex is not None:
+            if self._read_buffer:
+                m = self._read_regex.search(self._read_buffer)
+                if m is not None:
+                    loc = m.end()
+                    self._check_max_bytes(self._read_regex, loc)
+                    return loc
+                self._check_max_bytes(self._read_regex, self._read_buffer_size)
+        return None
+
+    def _check_max_bytes(self, delimiter: Union[bytes, Pattern], size: int) -> None:
+        if self._read_max_bytes is not None and size > self._read_max_bytes:
+            raise UnsatisfiableReadError(
+                "delimiter %r not found within %d bytes"
+                % (delimiter, self._read_max_bytes)
+            )
+
+    def _handle_write(self) -> None:
+        while True:
+            size = len(self._write_buffer)
+            if not size:
+                break
+            assert size > 0
+            try:
+                if _WINDOWS:
+                    # On windows, socket.send blows up if given a
+                    # write buffer that's too large, instead of just
+                    # returning the number of bytes it was able to
+                    # process.  Therefore we must not call socket.send
+                    # with more than 128KB at a time.
+                    size = 128 * 1024
+
+                num_bytes = self.write_to_fd(self._write_buffer.peek(size))
+                if num_bytes == 0:
+                    break
+                self._write_buffer.advance(num_bytes)
+                self._total_write_done_index += num_bytes
+            except BlockingIOError:
+                break
+            except (socket.error, IOError, OSError) as e:
+                if not self._is_connreset(e):
+                    # Broken pipe errors are usually caused by connection
+                    # reset, and its better to not log EPIPE errors to
+                    # minimize log spam
+                    gen_log.warning("Write error on %s: %s", self.fileno(), e)
+                self.close(exc_info=e)
+                return
+
+        while self._write_futures:
+            index, future = self._write_futures[0]
+            if index > self._total_write_done_index:
+                break
+            self._write_futures.popleft()
+            future_set_result_unless_cancelled(future, None)
+
+    def _consume(self, loc: int) -> bytes:
+        # Consume loc bytes from the read buffer and return them
+        if loc == 0:
+            return b""
+        assert loc <= self._read_buffer_size
+        # Slice the bytearray buffer into bytes, without intermediate copying
+        b = (memoryview(self._read_buffer)[:loc]).tobytes()
+        self._read_buffer_size -= loc
+        del self._read_buffer[:loc]
+        return b
+
+    def _check_closed(self) -> None:
+        if self.closed():
+            raise StreamClosedError(real_error=self.error)
+
+    def _maybe_add_error_listener(self) -> None:
+        # This method is part of an optimization: to detect a connection that
+        # is closed when we're not actively reading or writing, we must listen
+        # for read events.  However, it is inefficient to do this when the
+        # connection is first established because we are going to read or write
+        # immediately anyway.  Instead, we insert checks at various times to
+        # see if the connection is idle and add the read listener then.
+        if self._state is None or self._state == ioloop.IOLoop.ERROR:
+            if (
+                not self.closed()
+                and self._read_buffer_size == 0
+                and self._close_callback is not None
+            ):
+                self._add_io_state(ioloop.IOLoop.READ)
+
+    def _add_io_state(self, state: int) -> None:
+        """Adds `state` (IOLoop.{READ,WRITE} flags) to our event handler.
+
+        Implementation notes: Reads and writes have a fast path and a
+        slow path.  The fast path reads synchronously from socket
+        buffers, while the slow path uses `_add_io_state` to schedule
+        an IOLoop callback.
+
+        To detect closed connections, we must have called
+        `_add_io_state` at some point, but we want to delay this as
+        much as possible so we don't have to set an `IOLoop.ERROR`
+        listener that will be overwritten by the next slow-path
+        operation. If a sequence of fast-path ops do not end in a
+        slow-path op, (e.g. for an @asynchronous long-poll request),
+        we must add the error handler.
+
+        TODO: reevaluate this now that callbacks are gone.
+
+        """
+        if self.closed():
+            # connection has been closed, so there can be no future events
+            return
+        if self._state is None:
+            self._state = ioloop.IOLoop.ERROR | state
+            self.io_loop.add_handler(self.fileno(), self._handle_events, self._state)
+        elif not self._state & state:
+            self._state = self._state | state
+            self.io_loop.update_handler(self.fileno(), self._state)
+
+    def _is_connreset(self, exc: BaseException) -> bool:
+        """Return ``True`` if exc is ECONNRESET or equivalent.
+
+        May be overridden in subclasses.
+        """
+        return (
+            isinstance(exc, (socket.error, IOError))
+            and errno_from_exception(exc) in _ERRNO_CONNRESET
+        )
+
+
+class IOStream(BaseIOStream):
+    r"""Socket-based `IOStream` implementation.
+
+    This class supports the read and write methods from `BaseIOStream`
+    plus a `connect` method.
+
+    The ``socket`` parameter may either be connected or unconnected.
+    For server operations the socket is the result of calling
+    `socket.accept <socket.socket.accept>`.  For client operations the
+    socket is created with `socket.socket`, and may either be
+    connected before passing it to the `IOStream` or connected with
+    `IOStream.connect`.
+
+    A very simple (and broken) HTTP client using this class:
+
+    .. testcode::
+
+        import socket
+        import tornado
+
+        async def main():
+            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
+            stream = tornado.iostream.IOStream(s)
+            await stream.connect(("friendfeed.com", 80))
+            await stream.write(b"GET / HTTP/1.0\r\nHost: friendfeed.com\r\n\r\n")
+            header_data = await stream.read_until(b"\r\n\r\n")
+            headers = {}
+            for line in header_data.split(b"\r\n"):
+                parts = line.split(b":")
+                if len(parts) == 2:
+                    headers[parts[0].strip()] = parts[1].strip()
+            body_data = await stream.read_bytes(int(headers[b"Content-Length"]))
+            print(body_data)
+            stream.close()
+
+        if __name__ == '__main__':
+            asyncio.run(main())
+
+    .. testoutput::
+       :hide:
+
+    """
+
+    def __init__(self, socket: socket.socket, *args: Any, **kwargs: Any) -> None:
+        self.socket = socket
+        self.socket.setblocking(False)
+        super().__init__(*args, **kwargs)
+
+    def fileno(self) -> Union[int, ioloop._Selectable]:
+        return self.socket
+
+    def close_fd(self) -> None:
+        self.socket.close()
+        self.socket = None  # type: ignore
+
+    def get_fd_error(self) -> Optional[Exception]:
+        errno = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
+        return socket.error(errno, os.strerror(errno))
+
+    def read_from_fd(self, buf: Union[bytearray, memoryview]) -> Optional[int]:
+        try:
+            return self.socket.recv_into(buf, len(buf))
+        except BlockingIOError:
+            return None
+        finally:
+            del buf
+
+    def write_to_fd(self, data: memoryview) -> int:
+        try:
+            return self.socket.send(data)  # type: ignore
+        finally:
+            # Avoid keeping to data, which can be a memoryview.
+            # See https://github.com/tornadoweb/tornado/pull/2008
+            del data
+
+    def connect(
+        self: _IOStreamType, address: Any, server_hostname: Optional[str] = None
+    ) -> "Future[_IOStreamType]":
+        """Connects the socket to a remote address without blocking.
+
+        May only be called if the socket passed to the constructor was
+        not previously connected.  The address parameter is in the
+        same format as for `socket.connect <socket.socket.connect>` for
+        the type of socket passed to the IOStream constructor,
+        e.g. an ``(ip, port)`` tuple.  Hostnames are accepted here,
+        but will be resolved synchronously and block the IOLoop.
+        If you have a hostname instead of an IP address, the `.TCPClient`
+        class is recommended instead of calling this method directly.
+        `.TCPClient` will do asynchronous DNS resolution and handle
+        both IPv4 and IPv6.
+
+        If ``callback`` is specified, it will be called with no
+        arguments when the connection is completed; if not this method
+        returns a `.Future` (whose result after a successful
+        connection will be the stream itself).
+
+        In SSL mode, the ``server_hostname`` parameter will be used
+        for certificate validation (unless disabled in the
+        ``ssl_options``) and SNI (if supported; requires Python
+        2.7.9+).
+
+        Note that it is safe to call `IOStream.write
+        <BaseIOStream.write>` while the connection is pending, in
+        which case the data will be written as soon as the connection
+        is ready.  Calling `IOStream` read methods before the socket is
+        connected works on some platforms but is non-portable.
+
+        .. versionchanged:: 4.0
+            If no callback is given, returns a `.Future`.
+
+        .. versionchanged:: 4.2
+           SSL certificates are validated by default; pass
+           ``ssl_options=dict(cert_reqs=ssl.CERT_NONE)`` or a
+           suitably-configured `ssl.SSLContext` to the
+           `SSLIOStream` constructor to disable.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+        """
+        self._connecting = True
+        future = Future()  # type: Future[_IOStreamType]
+        self._connect_future = typing.cast("Future[IOStream]", future)
+        try:
+            self.socket.connect(address)
+        except BlockingIOError:
+            # In non-blocking mode we expect connect() to raise an
+            # exception with EINPROGRESS or EWOULDBLOCK.
+            pass
+        except socket.error as e:
+            # On freebsd, other errors such as ECONNREFUSED may be
+            # returned immediately when attempting to connect to
+            # localhost, so handle them the same way as an error
+            # reported later in _handle_connect.
+            if future is None:
+                gen_log.warning("Connect error on fd %s: %s", self.socket.fileno(), e)
+            self.close(exc_info=e)
+            return future
+        self._add_io_state(self.io_loop.WRITE)
+        return future
+
+    def start_tls(
+        self,
+        server_side: bool,
+        ssl_options: Optional[Union[Dict[str, Any], ssl.SSLContext]] = None,
+        server_hostname: Optional[str] = None,
+    ) -> Awaitable["SSLIOStream"]:
+        """Convert this `IOStream` to an `SSLIOStream`.
+
+        This enables protocols that begin in clear-text mode and
+        switch to SSL after some initial negotiation (such as the
+        ``STARTTLS`` extension to SMTP and IMAP).
+
+        This method cannot be used if there are outstanding reads
+        or writes on the stream, or if there is any data in the
+        IOStream's buffer (data in the operating system's socket
+        buffer is allowed).  This means it must generally be used
+        immediately after reading or writing the last clear-text
+        data.  It can also be used immediately after connecting,
+        before any reads or writes.
+
+        The ``ssl_options`` argument may be either an `ssl.SSLContext`
+        object or a dictionary of keyword arguments for the
+        `ssl.wrap_socket` function.  The ``server_hostname`` argument
+        will be used for certificate validation unless disabled
+        in the ``ssl_options``.
+
+        This method returns a `.Future` whose result is the new
+        `SSLIOStream`.  After this method has been called,
+        any other operation on the original stream is undefined.
+
+        If a close callback is defined on this stream, it will be
+        transferred to the new stream.
+
+        .. versionadded:: 4.0
+
+        .. versionchanged:: 4.2
+           SSL certificates are validated by default; pass
+           ``ssl_options=dict(cert_reqs=ssl.CERT_NONE)`` or a
+           suitably-configured `ssl.SSLContext` to disable.
+        """
+        if (
+            self._read_future
+            or self._write_futures
+            or self._connect_future
+            or self._closed
+            or self._read_buffer
+            or self._write_buffer
+        ):
+            raise ValueError("IOStream is not idle; cannot convert to SSL")
+        if ssl_options is None:
+            if server_side:
+                ssl_options = _server_ssl_defaults
+            else:
+                ssl_options = _client_ssl_defaults
+
+        socket = self.socket
+        self.io_loop.remove_handler(socket)
+        self.socket = None  # type: ignore
+        socket = ssl_wrap_socket(
+            socket,
+            ssl_options,
+            server_hostname=server_hostname,
+            server_side=server_side,
+            do_handshake_on_connect=False,
+        )
+        orig_close_callback = self._close_callback
+        self._close_callback = None
+
+        future = Future()  # type: Future[SSLIOStream]
+        ssl_stream = SSLIOStream(socket, ssl_options=ssl_options)
+        ssl_stream.set_close_callback(orig_close_callback)
+        ssl_stream._ssl_connect_future = future
+        ssl_stream.max_buffer_size = self.max_buffer_size
+        ssl_stream.read_chunk_size = self.read_chunk_size
+        return future
+
+    def _handle_connect(self) -> None:
+        try:
+            err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
+        except socket.error as e:
+            # Hurd doesn't allow SO_ERROR for loopback sockets because all
+            # errors for such sockets are reported synchronously.
+            if errno_from_exception(e) == errno.ENOPROTOOPT:
+                err = 0
+        if err != 0:
+            self.error = socket.error(err, os.strerror(err))
+            # IOLoop implementations may vary: some of them return
+            # an error state before the socket becomes writable, so
+            # in that case a connection failure would be handled by the
+            # error path in _handle_events instead of here.
+            if self._connect_future is None:
+                gen_log.warning(
+                    "Connect error on fd %s: %s",
+                    self.socket.fileno(),
+                    errno.errorcode[err],
+                )
+            self.close()
+            return
+        if self._connect_future is not None:
+            future = self._connect_future
+            self._connect_future = None
+            future_set_result_unless_cancelled(future, self)
+        self._connecting = False
+
+    def set_nodelay(self, value: bool) -> None:
+        if self.socket is not None and self.socket.family in (
+            socket.AF_INET,
+            socket.AF_INET6,
+        ):
+            try:
+                self.socket.setsockopt(
+                    socket.IPPROTO_TCP, socket.TCP_NODELAY, 1 if value else 0
+                )
+            except socket.error as e:
+                # Sometimes setsockopt will fail if the socket is closed
+                # at the wrong time.  This can happen with HTTPServer
+                # resetting the value to ``False`` between requests.
+                if e.errno != errno.EINVAL and not self._is_connreset(e):
+                    raise
+
+
+class SSLIOStream(IOStream):
+    """A utility class to write to and read from a non-blocking SSL socket.
+
+    If the socket passed to the constructor is already connected,
+    it should be wrapped with::
+
+        ssl.wrap_socket(sock, do_handshake_on_connect=False, **kwargs)
+
+    before constructing the `SSLIOStream`.  Unconnected sockets will be
+    wrapped when `IOStream.connect` is finished.
+    """
+
+    socket = None  # type: ssl.SSLSocket
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        """The ``ssl_options`` keyword argument may either be an
+        `ssl.SSLContext` object or a dictionary of keywords arguments
+        for `ssl.wrap_socket`
+        """
+        self._ssl_options = kwargs.pop("ssl_options", _client_ssl_defaults)
+        super().__init__(*args, **kwargs)
+        self._ssl_accepting = True
+        self._handshake_reading = False
+        self._handshake_writing = False
+        self._server_hostname = None  # type: Optional[str]
+
+        # If the socket is already connected, attempt to start the handshake.
+        try:
+            self.socket.getpeername()
+        except socket.error:
+            pass
+        else:
+            # Indirectly start the handshake, which will run on the next
+            # IOLoop iteration and then the real IO state will be set in
+            # _handle_events.
+            self._add_io_state(self.io_loop.WRITE)
+
+    def reading(self) -> bool:
+        return self._handshake_reading or super().reading()
+
+    def writing(self) -> bool:
+        return self._handshake_writing or super().writing()
+
+    def _do_ssl_handshake(self) -> None:
+        # Based on code from test_ssl.py in the python stdlib
+        try:
+            self._handshake_reading = False
+            self._handshake_writing = False
+            self.socket.do_handshake()
+        except ssl.SSLError as err:
+            if err.args[0] == ssl.SSL_ERROR_WANT_READ:
+                self._handshake_reading = True
+                return
+            elif err.args[0] == ssl.SSL_ERROR_WANT_WRITE:
+                self._handshake_writing = True
+                return
+            elif err.args[0] in (ssl.SSL_ERROR_EOF, ssl.SSL_ERROR_ZERO_RETURN):
+                return self.close(exc_info=err)
+            elif err.args[0] == ssl.SSL_ERROR_SSL:
+                try:
+                    peer = self.socket.getpeername()
+                except Exception:
+                    peer = "(not connected)"
+                gen_log.warning(
+                    "SSL Error on %s %s: %s", self.socket.fileno(), peer, err
+                )
+                return self.close(exc_info=err)
+            raise
+        except ssl.CertificateError as err:
+            # CertificateError can happen during handshake (hostname
+            # verification) and should be passed to user. Starting
+            # in Python 3.7, this error is a subclass of SSLError
+            # and will be handled by the previous block instead.
+            return self.close(exc_info=err)
+        except socket.error as err:
+            # Some port scans (e.g. nmap in -sT mode) have been known
+            # to cause do_handshake to raise EBADF and ENOTCONN, so make
+            # those errors quiet as well.
+            # https://groups.google.com/forum/?fromgroups#!topic/python-tornado/ApucKJat1_0
+            # Errno 0 is also possible in some cases (nc -z).
+            # https://github.com/tornadoweb/tornado/issues/2504
+            if self._is_connreset(err) or err.args[0] in (
+                0,
+                errno.EBADF,
+                errno.ENOTCONN,
+            ):
+                return self.close(exc_info=err)
+            raise
+        except AttributeError as err:
+            # On Linux, if the connection was reset before the call to
+            # wrap_socket, do_handshake will fail with an
+            # AttributeError.
+            return self.close(exc_info=err)
+        else:
+            self._ssl_accepting = False
+            if not self._verify_cert(self.socket.getpeercert()):
+                self.close()
+                return
+            self._finish_ssl_connect()
+
+    def _finish_ssl_connect(self) -> None:
+        if self._ssl_connect_future is not None:
+            future = self._ssl_connect_future
+            self._ssl_connect_future = None
+            future_set_result_unless_cancelled(future, self)
+
+    def _verify_cert(self, peercert: Any) -> bool:
+        """Returns ``True`` if peercert is valid according to the configured
+        validation mode and hostname.
+
+        The ssl handshake already tested the certificate for a valid
+        CA signature; the only thing that remains is to check
+        the hostname.
+        """
+        if isinstance(self._ssl_options, dict):
+            verify_mode = self._ssl_options.get("cert_reqs", ssl.CERT_NONE)
+        elif isinstance(self._ssl_options, ssl.SSLContext):
+            verify_mode = self._ssl_options.verify_mode
+        assert verify_mode in (ssl.CERT_NONE, ssl.CERT_REQUIRED, ssl.CERT_OPTIONAL)
+        if verify_mode == ssl.CERT_NONE or self._server_hostname is None:
+            return True
+        cert = self.socket.getpeercert()
+        if cert is None and verify_mode == ssl.CERT_REQUIRED:
+            gen_log.warning("No SSL certificate given")
+            return False
+        try:
+            ssl.match_hostname(peercert, self._server_hostname)
+        except ssl.CertificateError as e:
+            gen_log.warning("Invalid SSL certificate: %s" % e)
+            return False
+        else:
+            return True
+
+    def _handle_read(self) -> None:
+        if self._ssl_accepting:
+            self._do_ssl_handshake()
+            return
+        super()._handle_read()
+
+    def _handle_write(self) -> None:
+        if self._ssl_accepting:
+            self._do_ssl_handshake()
+            return
+        super()._handle_write()
+
+    def connect(
+        self, address: Tuple, server_hostname: Optional[str] = None
+    ) -> "Future[SSLIOStream]":
+        self._server_hostname = server_hostname
+        # Ignore the result of connect(). If it fails,
+        # wait_for_handshake will raise an error too. This is
+        # necessary for the old semantics of the connect callback
+        # (which takes no arguments). In 6.0 this can be refactored to
+        # be a regular coroutine.
+        # TODO: This is trickier than it looks, since if write()
+        # is called with a connect() pending, we want the connect
+        # to resolve before the write. Or do we care about this?
+        # (There's a test for it, but I think in practice users
+        # either wait for the connect before performing a write or
+        # they don't care about the connect Future at all)
+        fut = super().connect(address)
+        fut.add_done_callback(lambda f: f.exception())
+        return self.wait_for_handshake()
+
+    def _handle_connect(self) -> None:
+        # Call the superclass method to check for errors.
+        super()._handle_connect()
+        if self.closed():
+            return
+        # When the connection is complete, wrap the socket for SSL
+        # traffic.  Note that we do this by overriding _handle_connect
+        # instead of by passing a callback to super().connect because
+        # user callbacks are enqueued asynchronously on the IOLoop,
+        # but since _handle_events calls _handle_connect immediately
+        # followed by _handle_write we need this to be synchronous.
+        #
+        # The IOLoop will get confused if we swap out self.socket while the
+        # fd is registered, so remove it now and re-register after
+        # wrap_socket().
+        self.io_loop.remove_handler(self.socket)
+        old_state = self._state
+        assert old_state is not None
+        self._state = None
+        self.socket = ssl_wrap_socket(
+            self.socket,
+            self._ssl_options,
+            server_hostname=self._server_hostname,
+            do_handshake_on_connect=False,
+            server_side=False,
+        )
+        self._add_io_state(old_state)
+
+    def wait_for_handshake(self) -> "Future[SSLIOStream]":
+        """Wait for the initial SSL handshake to complete.
+
+        If a ``callback`` is given, it will be called with no
+        arguments once the handshake is complete; otherwise this
+        method returns a `.Future` which will resolve to the
+        stream itself after the handshake is complete.
+
+        Once the handshake is complete, information such as
+        the peer's certificate and NPN/ALPN selections may be
+        accessed on ``self.socket``.
+
+        This method is intended for use on server-side streams
+        or after using `IOStream.start_tls`; it should not be used
+        with `IOStream.connect` (which already waits for the
+        handshake to complete). It may only be called once per stream.
+
+        .. versionadded:: 4.2
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed. Use the returned
+           `.Future` instead.
+
+        """
+        if self._ssl_connect_future is not None:
+            raise RuntimeError("Already waiting")
+        future = self._ssl_connect_future = Future()
+        if not self._ssl_accepting:
+            self._finish_ssl_connect()
+        return future
+
+    def write_to_fd(self, data: memoryview) -> int:
+        # clip buffer size at 1GB since SSL sockets only support upto 2GB
+        # this change in behaviour is transparent, since the function is
+        # already expected to (possibly) write less than the provided buffer
+        if len(data) >> 30:
+            data = memoryview(data)[: 1 << 30]
+        try:
+            return self.socket.send(data)  # type: ignore
+        except ssl.SSLError as e:
+            if e.args[0] == ssl.SSL_ERROR_WANT_WRITE:
+                # In Python 3.5+, SSLSocket.send raises a WANT_WRITE error if
+                # the socket is not writeable; we need to transform this into
+                # an EWOULDBLOCK socket.error or a zero return value,
+                # either of which will be recognized by the caller of this
+                # method. Prior to Python 3.5, an unwriteable socket would
+                # simply return 0 bytes written.
+                return 0
+            raise
+        finally:
+            # Avoid keeping to data, which can be a memoryview.
+            # See https://github.com/tornadoweb/tornado/pull/2008
+            del data
+
+    def read_from_fd(self, buf: Union[bytearray, memoryview]) -> Optional[int]:
+        try:
+            if self._ssl_accepting:
+                # If the handshake hasn't finished yet, there can't be anything
+                # to read (attempting to read may or may not raise an exception
+                # depending on the SSL version)
+                return None
+            # clip buffer size at 1GB since SSL sockets only support upto 2GB
+            # this change in behaviour is transparent, since the function is
+            # already expected to (possibly) read less than the provided buffer
+            if len(buf) >> 30:
+                buf = memoryview(buf)[: 1 << 30]
+            try:
+                return self.socket.recv_into(buf, len(buf))
+            except ssl.SSLError as e:
+                # SSLError is a subclass of socket.error, so this except
+                # block must come first.
+                if e.args[0] == ssl.SSL_ERROR_WANT_READ:
+                    return None
+                else:
+                    raise
+            except BlockingIOError:
+                return None
+        finally:
+            del buf
+
+    def _is_connreset(self, e: BaseException) -> bool:
+        if isinstance(e, ssl.SSLError) and e.args[0] == ssl.SSL_ERROR_EOF:
+            return True
+        return super()._is_connreset(e)
+
+
+class PipeIOStream(BaseIOStream):
+    """Pipe-based `IOStream` implementation.
+
+    The constructor takes an integer file descriptor (such as one returned
+    by `os.pipe`) rather than an open file object.  Pipes are generally
+    one-way, so a `PipeIOStream` can be used for reading or writing but not
+    both.
+
+    ``PipeIOStream`` is only available on Unix-based platforms.
+    """
+
+    def __init__(self, fd: int, *args: Any, **kwargs: Any) -> None:
+        self.fd = fd
+        self._fio = io.FileIO(self.fd, "r+")
+        if sys.platform == "win32":
+            # The form and placement of this assertion is important to mypy.
+            # A plain assert statement isn't recognized here. If the assertion
+            # were earlier it would worry that the attributes of self aren't
+            # set on windows. If it were missing it would complain about
+            # the absence of the set_blocking function.
+            raise AssertionError("PipeIOStream is not supported on Windows")
+        os.set_blocking(fd, False)
+        super().__init__(*args, **kwargs)
+
+    def fileno(self) -> int:
+        return self.fd
+
+    def close_fd(self) -> None:
+        self._fio.close()
+
+    def write_to_fd(self, data: memoryview) -> int:
+        try:
+            return os.write(self.fd, data)  # type: ignore
+        finally:
+            # Avoid keeping to data, which can be a memoryview.
+            # See https://github.com/tornadoweb/tornado/pull/2008
+            del data
+
+    def read_from_fd(self, buf: Union[bytearray, memoryview]) -> Optional[int]:
+        try:
+            return self._fio.readinto(buf)  # type: ignore
+        except (IOError, OSError) as e:
+            if errno_from_exception(e) == errno.EBADF:
+                # If the writing half of a pipe is closed, select will
+                # report it as readable but reads will fail with EBADF.
+                self.close(exc_info=e)
+                return None
+            else:
+                raise
+        finally:
+            del buf
+
+
+def doctests() -> Any:
+    import doctest
+
+    return doctest.DocTestSuite()
diff --git a/venv/lib/python3.9/site-packages/tornado/locale.py b/venv/lib/python3.9/site-packages/tornado/locale.py
new file mode 100644
index 00000000..55072af2
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/locale.py
@@ -0,0 +1,581 @@
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Translation methods for generating localized strings.
+
+To load a locale and generate a translated string::
+
+    user_locale = tornado.locale.get("es_LA")
+    print(user_locale.translate("Sign out"))
+
+`tornado.locale.get()` returns the closest matching locale, not necessarily the
+specific locale you requested. You can support pluralization with
+additional arguments to `~Locale.translate()`, e.g.::
+
+    people = [...]
+    message = user_locale.translate(
+        "%(list)s is online", "%(list)s are online", len(people))
+    print(message % {"list": user_locale.list(people)})
+
+The first string is chosen if ``len(people) == 1``, otherwise the second
+string is chosen.
+
+Applications should call one of `load_translations` (which uses a simple
+CSV format) or `load_gettext_translations` (which uses the ``.mo`` format
+supported by `gettext` and related tools).  If neither method is called,
+the `Locale.translate` method will simply return the original string.
+"""
+
+import codecs
+import csv
+import datetime
+import gettext
+import glob
+import os
+import re
+
+from tornado import escape
+from tornado.log import gen_log
+
+from tornado._locale_data import LOCALE_NAMES
+
+from typing import Iterable, Any, Union, Dict, Optional
+
+_default_locale = "en_US"
+_translations = {}  # type: Dict[str, Any]
+_supported_locales = frozenset([_default_locale])
+_use_gettext = False
+CONTEXT_SEPARATOR = "\x04"
+
+
+def get(*locale_codes: str) -> "Locale":
+    """Returns the closest match for the given locale codes.
+
+    We iterate over all given locale codes in order. If we have a tight
+    or a loose match for the code (e.g., "en" for "en_US"), we return
+    the locale. Otherwise we move to the next code in the list.
+
+    By default we return ``en_US`` if no translations are found for any of
+    the specified locales. You can change the default locale with
+    `set_default_locale()`.
+    """
+    return Locale.get_closest(*locale_codes)
+
+
+def set_default_locale(code: str) -> None:
+    """Sets the default locale.
+
+    The default locale is assumed to be the language used for all strings
+    in the system. The translations loaded from disk are mappings from
+    the default locale to the destination locale. Consequently, you don't
+    need to create a translation file for the default locale.
+    """
+    global _default_locale
+    global _supported_locales
+    _default_locale = code
+    _supported_locales = frozenset(list(_translations.keys()) + [_default_locale])
+
+
+def load_translations(directory: str, encoding: Optional[str] = None) -> None:
+    """Loads translations from CSV files in a directory.
+
+    Translations are strings with optional Python-style named placeholders
+    (e.g., ``My name is %(name)s``) and their associated translations.
+
+    The directory should have translation files of the form ``LOCALE.csv``,
+    e.g. ``es_GT.csv``. The CSV files should have two or three columns: string,
+    translation, and an optional plural indicator. Plural indicators should
+    be one of "plural" or "singular". A given string can have both singular
+    and plural forms. For example ``%(name)s liked this`` may have a
+    different verb conjugation depending on whether %(name)s is one
+    name or a list of names. There should be two rows in the CSV file for
+    that string, one with plural indicator "singular", and one "plural".
+    For strings with no verbs that would change on translation, simply
+    use "unknown" or the empty string (or don't include the column at all).
+
+    The file is read using the `csv` module in the default "excel" dialect.
+    In this format there should not be spaces after the commas.
+
+    If no ``encoding`` parameter is given, the encoding will be
+    detected automatically (among UTF-8 and UTF-16) if the file
+    contains a byte-order marker (BOM), defaulting to UTF-8 if no BOM
+    is present.
+
+    Example translation ``es_LA.csv``::
+
+        "I love you","Te amo"
+        "%(name)s liked this","A %(name)s les gustó esto","plural"
+        "%(name)s liked this","A %(name)s le gustó esto","singular"
+
+    .. versionchanged:: 4.3
+       Added ``encoding`` parameter. Added support for BOM-based encoding
+       detection, UTF-16, and UTF-8-with-BOM.
+    """
+    global _translations
+    global _supported_locales
+    _translations = {}
+    for path in os.listdir(directory):
+        if not path.endswith(".csv"):
+            continue
+        locale, extension = path.split(".")
+        if not re.match("[a-z]+(_[A-Z]+)?$", locale):
+            gen_log.error(
+                "Unrecognized locale %r (path: %s)",
+                locale,
+                os.path.join(directory, path),
+            )
+            continue
+        full_path = os.path.join(directory, path)
+        if encoding is None:
+            # Try to autodetect encoding based on the BOM.
+            with open(full_path, "rb") as bf:
+                data = bf.read(len(codecs.BOM_UTF16_LE))
+            if data in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE):
+                encoding = "utf-16"
+            else:
+                # utf-8-sig is "utf-8 with optional BOM". It's discouraged
+                # in most cases but is common with CSV files because Excel
+                # cannot read utf-8 files without a BOM.
+                encoding = "utf-8-sig"
+        # python 3: csv.reader requires a file open in text mode.
+        # Specify an encoding to avoid dependence on $LANG environment variable.
+        with open(full_path, encoding=encoding) as f:
+            _translations[locale] = {}
+            for i, row in enumerate(csv.reader(f)):
+                if not row or len(row) < 2:
+                    continue
+                row = [escape.to_unicode(c).strip() for c in row]
+                english, translation = row[:2]
+                if len(row) > 2:
+                    plural = row[2] or "unknown"
+                else:
+                    plural = "unknown"
+                if plural not in ("plural", "singular", "unknown"):
+                    gen_log.error(
+                        "Unrecognized plural indicator %r in %s line %d",
+                        plural,
+                        path,
+                        i + 1,
+                    )
+                    continue
+                _translations[locale].setdefault(plural, {})[english] = translation
+    _supported_locales = frozenset(list(_translations.keys()) + [_default_locale])
+    gen_log.debug("Supported locales: %s", sorted(_supported_locales))
+
+
+def load_gettext_translations(directory: str, domain: str) -> None:
+    """Loads translations from `gettext`'s locale tree
+
+    Locale tree is similar to system's ``/usr/share/locale``, like::
+
+        {directory}/{lang}/LC_MESSAGES/{domain}.mo
+
+    Three steps are required to have your app translated:
+
+    1. Generate POT translation file::
+
+        xgettext --language=Python --keyword=_:1,2 -d mydomain file1.py file2.html etc
+
+    2. Merge against existing POT file::
+
+        msgmerge old.po mydomain.po > new.po
+
+    3. Compile::
+
+        msgfmt mydomain.po -o {directory}/pt_BR/LC_MESSAGES/mydomain.mo
+    """
+    global _translations
+    global _supported_locales
+    global _use_gettext
+    _translations = {}
+
+    for filename in glob.glob(
+        os.path.join(directory, "*", "LC_MESSAGES", domain + ".mo")
+    ):
+        lang = os.path.basename(os.path.dirname(os.path.dirname(filename)))
+        try:
+            _translations[lang] = gettext.translation(
+                domain, directory, languages=[lang]
+            )
+        except Exception as e:
+            gen_log.error("Cannot load translation for '%s': %s", lang, str(e))
+            continue
+    _supported_locales = frozenset(list(_translations.keys()) + [_default_locale])
+    _use_gettext = True
+    gen_log.debug("Supported locales: %s", sorted(_supported_locales))
+
+
+def get_supported_locales() -> Iterable[str]:
+    """Returns a list of all the supported locale codes."""
+    return _supported_locales
+
+
+class Locale(object):
+    """Object representing a locale.
+
+    After calling one of `load_translations` or `load_gettext_translations`,
+    call `get` or `get_closest` to get a Locale object.
+    """
+
+    _cache = {}  # type: Dict[str, Locale]
+
+    @classmethod
+    def get_closest(cls, *locale_codes: str) -> "Locale":
+        """Returns the closest match for the given locale code."""
+        for code in locale_codes:
+            if not code:
+                continue
+            code = code.replace("-", "_")
+            parts = code.split("_")
+            if len(parts) > 2:
+                continue
+            elif len(parts) == 2:
+                code = parts[0].lower() + "_" + parts[1].upper()
+            if code in _supported_locales:
+                return cls.get(code)
+            if parts[0].lower() in _supported_locales:
+                return cls.get(parts[0].lower())
+        return cls.get(_default_locale)
+
+    @classmethod
+    def get(cls, code: str) -> "Locale":
+        """Returns the Locale for the given locale code.
+
+        If it is not supported, we raise an exception.
+        """
+        if code not in cls._cache:
+            assert code in _supported_locales
+            translations = _translations.get(code, None)
+            if translations is None:
+                locale = CSVLocale(code, {})  # type: Locale
+            elif _use_gettext:
+                locale = GettextLocale(code, translations)
+            else:
+                locale = CSVLocale(code, translations)
+            cls._cache[code] = locale
+        return cls._cache[code]
+
+    def __init__(self, code: str) -> None:
+        self.code = code
+        self.name = LOCALE_NAMES.get(code, {}).get("name", "Unknown")
+        self.rtl = False
+        for prefix in ["fa", "ar", "he"]:
+            if self.code.startswith(prefix):
+                self.rtl = True
+                break
+
+        # Initialize strings for date formatting
+        _ = self.translate
+        self._months = [
+            _("January"),
+            _("February"),
+            _("March"),
+            _("April"),
+            _("May"),
+            _("June"),
+            _("July"),
+            _("August"),
+            _("September"),
+            _("October"),
+            _("November"),
+            _("December"),
+        ]
+        self._weekdays = [
+            _("Monday"),
+            _("Tuesday"),
+            _("Wednesday"),
+            _("Thursday"),
+            _("Friday"),
+            _("Saturday"),
+            _("Sunday"),
+        ]
+
+    def translate(
+        self,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        """Returns the translation for the given message for this locale.
+
+        If ``plural_message`` is given, you must also provide
+        ``count``. We return ``plural_message`` when ``count != 1``,
+        and we return the singular form for the given message when
+        ``count == 1``.
+        """
+        raise NotImplementedError()
+
+    def pgettext(
+        self,
+        context: str,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        raise NotImplementedError()
+
+    def format_date(
+        self,
+        date: Union[int, float, datetime.datetime],
+        gmt_offset: int = 0,
+        relative: bool = True,
+        shorter: bool = False,
+        full_format: bool = False,
+    ) -> str:
+        """Formats the given date (which should be GMT).
+
+        By default, we return a relative time (e.g., "2 minutes ago"). You
+        can return an absolute date string with ``relative=False``.
+
+        You can force a full format date ("July 10, 1980") with
+        ``full_format=True``.
+
+        This method is primarily intended for dates in the past.
+        For dates in the future, we fall back to full format.
+        """
+        if isinstance(date, (int, float)):
+            date = datetime.datetime.utcfromtimestamp(date)
+        now = datetime.datetime.utcnow()
+        if date > now:
+            if relative and (date - now).seconds < 60:
+                # Due to click skew, things are some things slightly
+                # in the future. Round timestamps in the immediate
+                # future down to now in relative mode.
+                date = now
+            else:
+                # Otherwise, future dates always use the full format.
+                full_format = True
+        local_date = date - datetime.timedelta(minutes=gmt_offset)
+        local_now = now - datetime.timedelta(minutes=gmt_offset)
+        local_yesterday = local_now - datetime.timedelta(hours=24)
+        difference = now - date
+        seconds = difference.seconds
+        days = difference.days
+
+        _ = self.translate
+        format = None
+        if not full_format:
+            if relative and days == 0:
+                if seconds < 50:
+                    return _("1 second ago", "%(seconds)d seconds ago", seconds) % {
+                        "seconds": seconds
+                    }
+
+                if seconds < 50 * 60:
+                    minutes = round(seconds / 60.0)
+                    return _("1 minute ago", "%(minutes)d minutes ago", minutes) % {
+                        "minutes": minutes
+                    }
+
+                hours = round(seconds / (60.0 * 60))
+                return _("1 hour ago", "%(hours)d hours ago", hours) % {"hours": hours}
+
+            if days == 0:
+                format = _("%(time)s")
+            elif days == 1 and local_date.day == local_yesterday.day and relative:
+                format = _("yesterday") if shorter else _("yesterday at %(time)s")
+            elif days < 5:
+                format = _("%(weekday)s") if shorter else _("%(weekday)s at %(time)s")
+            elif days < 334:  # 11mo, since confusing for same month last year
+                format = (
+                    _("%(month_name)s %(day)s")
+                    if shorter
+                    else _("%(month_name)s %(day)s at %(time)s")
+                )
+
+        if format is None:
+            format = (
+                _("%(month_name)s %(day)s, %(year)s")
+                if shorter
+                else _("%(month_name)s %(day)s, %(year)s at %(time)s")
+            )
+
+        tfhour_clock = self.code not in ("en", "en_US", "zh_CN")
+        if tfhour_clock:
+            str_time = "%d:%02d" % (local_date.hour, local_date.minute)
+        elif self.code == "zh_CN":
+            str_time = "%s%d:%02d" % (
+                ("\u4e0a\u5348", "\u4e0b\u5348")[local_date.hour >= 12],
+                local_date.hour % 12 or 12,
+                local_date.minute,
+            )
+        else:
+            str_time = "%d:%02d %s" % (
+                local_date.hour % 12 or 12,
+                local_date.minute,
+                ("am", "pm")[local_date.hour >= 12],
+            )
+
+        return format % {
+            "month_name": self._months[local_date.month - 1],
+            "weekday": self._weekdays[local_date.weekday()],
+            "day": str(local_date.day),
+            "year": str(local_date.year),
+            "time": str_time,
+        }
+
+    def format_day(
+        self, date: datetime.datetime, gmt_offset: int = 0, dow: bool = True
+    ) -> bool:
+        """Formats the given date as a day of week.
+
+        Example: "Monday, January 22". You can remove the day of week with
+        ``dow=False``.
+        """
+        local_date = date - datetime.timedelta(minutes=gmt_offset)
+        _ = self.translate
+        if dow:
+            return _("%(weekday)s, %(month_name)s %(day)s") % {
+                "month_name": self._months[local_date.month - 1],
+                "weekday": self._weekdays[local_date.weekday()],
+                "day": str(local_date.day),
+            }
+        else:
+            return _("%(month_name)s %(day)s") % {
+                "month_name": self._months[local_date.month - 1],
+                "day": str(local_date.day),
+            }
+
+    def list(self, parts: Any) -> str:
+        """Returns a comma-separated list for the given list of parts.
+
+        The format is, e.g., "A, B and C", "A and B" or just "A" for lists
+        of size 1.
+        """
+        _ = self.translate
+        if len(parts) == 0:
+            return ""
+        if len(parts) == 1:
+            return parts[0]
+        comma = " \u0648 " if self.code.startswith("fa") else ", "
+        return _("%(commas)s and %(last)s") % {
+            "commas": comma.join(parts[:-1]),
+            "last": parts[len(parts) - 1],
+        }
+
+    def friendly_number(self, value: int) -> str:
+        """Returns a comma-separated number for the given integer."""
+        if self.code not in ("en", "en_US"):
+            return str(value)
+        s = str(value)
+        parts = []
+        while s:
+            parts.append(s[-3:])
+            s = s[:-3]
+        return ",".join(reversed(parts))
+
+
+class CSVLocale(Locale):
+    """Locale implementation using tornado's CSV translation format."""
+
+    def __init__(self, code: str, translations: Dict[str, Dict[str, str]]) -> None:
+        self.translations = translations
+        super().__init__(code)
+
+    def translate(
+        self,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        if plural_message is not None:
+            assert count is not None
+            if count != 1:
+                message = plural_message
+                message_dict = self.translations.get("plural", {})
+            else:
+                message_dict = self.translations.get("singular", {})
+        else:
+            message_dict = self.translations.get("unknown", {})
+        return message_dict.get(message, message)
+
+    def pgettext(
+        self,
+        context: str,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        if self.translations:
+            gen_log.warning("pgettext is not supported by CSVLocale")
+        return self.translate(message, plural_message, count)
+
+
+class GettextLocale(Locale):
+    """Locale implementation using the `gettext` module."""
+
+    def __init__(self, code: str, translations: gettext.NullTranslations) -> None:
+        self.ngettext = translations.ngettext
+        self.gettext = translations.gettext
+        # self.gettext must exist before __init__ is called, since it
+        # calls into self.translate
+        super().__init__(code)
+
+    def translate(
+        self,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        if plural_message is not None:
+            assert count is not None
+            return self.ngettext(message, plural_message, count)
+        else:
+            return self.gettext(message)
+
+    def pgettext(
+        self,
+        context: str,
+        message: str,
+        plural_message: Optional[str] = None,
+        count: Optional[int] = None,
+    ) -> str:
+        """Allows to set context for translation, accepts plural forms.
+
+        Usage example::
+
+            pgettext("law", "right")
+            pgettext("good", "right")
+
+        Plural message example::
+
+            pgettext("organization", "club", "clubs", len(clubs))
+            pgettext("stick", "club", "clubs", len(clubs))
+
+        To generate POT file with context, add following options to step 1
+        of `load_gettext_translations` sequence::
+
+            xgettext [basic options] --keyword=pgettext:1c,2 --keyword=pgettext:1c,2,3
+
+        .. versionadded:: 4.2
+        """
+        if plural_message is not None:
+            assert count is not None
+            msgs_with_ctxt = (
+                "%s%s%s" % (context, CONTEXT_SEPARATOR, message),
+                "%s%s%s" % (context, CONTEXT_SEPARATOR, plural_message),
+                count,
+            )
+            result = self.ngettext(*msgs_with_ctxt)
+            if CONTEXT_SEPARATOR in result:
+                # Translation not found
+                result = self.ngettext(message, plural_message, count)
+            return result
+        else:
+            msg_with_ctxt = "%s%s%s" % (context, CONTEXT_SEPARATOR, message)
+            result = self.gettext(msg_with_ctxt)
+            if CONTEXT_SEPARATOR in result:
+                # Translation not found
+                result = message
+            return result
diff --git a/venv/lib/python3.9/site-packages/tornado/locks.py b/venv/lib/python3.9/site-packages/tornado/locks.py
new file mode 100644
index 00000000..1bcec1b3
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/locks.py
@@ -0,0 +1,572 @@
+# Copyright 2015 The Tornado Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import collections
+import datetime
+import types
+
+from tornado import gen, ioloop
+from tornado.concurrent import Future, future_set_result_unless_cancelled
+
+from typing import Union, Optional, Type, Any, Awaitable
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Deque, Set  # noqa: F401
+
+__all__ = ["Condition", "Event", "Semaphore", "BoundedSemaphore", "Lock"]
+
+
+class _TimeoutGarbageCollector(object):
+    """Base class for objects that periodically clean up timed-out waiters.
+
+    Avoids memory leak in a common pattern like:
+
+        while True:
+            yield condition.wait(short_timeout)
+            print('looping....')
+    """
+
+    def __init__(self) -> None:
+        self._waiters = collections.deque()  # type: Deque[Future]
+        self._timeouts = 0
+
+    def _garbage_collect(self) -> None:
+        # Occasionally clear timed-out waiters.
+        self._timeouts += 1
+        if self._timeouts > 100:
+            self._timeouts = 0
+            self._waiters = collections.deque(w for w in self._waiters if not w.done())
+
+
+class Condition(_TimeoutGarbageCollector):
+    """A condition allows one or more coroutines to wait until notified.
+
+    Like a standard `threading.Condition`, but does not need an underlying lock
+    that is acquired and released.
+
+    With a `Condition`, coroutines can wait to be notified by other coroutines:
+
+    .. testcode::
+
+        import asyncio
+        from tornado import gen
+        from tornado.locks import Condition
+
+        condition = Condition()
+
+        async def waiter():
+            print("I'll wait right here")
+            await condition.wait()
+            print("I'm done waiting")
+
+        async def notifier():
+            print("About to notify")
+            condition.notify()
+            print("Done notifying")
+
+        async def runner():
+            # Wait for waiter() and notifier() in parallel
+            await gen.multi([waiter(), notifier()])
+
+        asyncio.run(runner())
+
+    .. testoutput::
+
+        I'll wait right here
+        About to notify
+        Done notifying
+        I'm done waiting
+
+    `wait` takes an optional ``timeout`` argument, which is either an absolute
+    timestamp::
+
+        io_loop = IOLoop.current()
+
+        # Wait up to 1 second for a notification.
+        await condition.wait(timeout=io_loop.time() + 1)
+
+    ...or a `datetime.timedelta` for a timeout relative to the current time::
+
+        # Wait up to 1 second.
+        await condition.wait(timeout=datetime.timedelta(seconds=1))
+
+    The method returns False if there's no notification before the deadline.
+
+    .. versionchanged:: 5.0
+       Previously, waiters could be notified synchronously from within
+       `notify`. Now, the notification will always be received on the
+       next iteration of the `.IOLoop`.
+    """
+
+    def __repr__(self) -> str:
+        result = "<%s" % (self.__class__.__name__,)
+        if self._waiters:
+            result += " waiters[%s]" % len(self._waiters)
+        return result + ">"
+
+    def wait(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[bool]:
+        """Wait for `.notify`.
+
+        Returns a `.Future` that resolves ``True`` if the condition is notified,
+        or ``False`` after a timeout.
+        """
+        waiter = Future()  # type: Future[bool]
+        self._waiters.append(waiter)
+        if timeout:
+
+            def on_timeout() -> None:
+                if not waiter.done():
+                    future_set_result_unless_cancelled(waiter, False)
+                self._garbage_collect()
+
+            io_loop = ioloop.IOLoop.current()
+            timeout_handle = io_loop.add_timeout(timeout, on_timeout)
+            waiter.add_done_callback(lambda _: io_loop.remove_timeout(timeout_handle))
+        return waiter
+
+    def notify(self, n: int = 1) -> None:
+        """Wake ``n`` waiters."""
+        waiters = []  # Waiters we plan to run right now.
+        while n and self._waiters:
+            waiter = self._waiters.popleft()
+            if not waiter.done():  # Might have timed out.
+                n -= 1
+                waiters.append(waiter)
+
+        for waiter in waiters:
+            future_set_result_unless_cancelled(waiter, True)
+
+    def notify_all(self) -> None:
+        """Wake all waiters."""
+        self.notify(len(self._waiters))
+
+
+class Event(object):
+    """An event blocks coroutines until its internal flag is set to True.
+
+    Similar to `threading.Event`.
+
+    A coroutine can wait for an event to be set. Once it is set, calls to
+    ``yield event.wait()`` will not block unless the event has been cleared:
+
+    .. testcode::
+
+        import asyncio
+        from tornado import gen
+        from tornado.locks import Event
+
+        event = Event()
+
+        async def waiter():
+            print("Waiting for event")
+            await event.wait()
+            print("Not waiting this time")
+            await event.wait()
+            print("Done")
+
+        async def setter():
+            print("About to set the event")
+            event.set()
+
+        async def runner():
+            await gen.multi([waiter(), setter()])
+
+        asyncio.run(runner())
+
+    .. testoutput::
+
+        Waiting for event
+        About to set the event
+        Not waiting this time
+        Done
+    """
+
+    def __init__(self) -> None:
+        self._value = False
+        self._waiters = set()  # type: Set[Future[None]]
+
+    def __repr__(self) -> str:
+        return "<%s %s>" % (
+            self.__class__.__name__,
+            "set" if self.is_set() else "clear",
+        )
+
+    def is_set(self) -> bool:
+        """Return ``True`` if the internal flag is true."""
+        return self._value
+
+    def set(self) -> None:
+        """Set the internal flag to ``True``. All waiters are awakened.
+
+        Calling `.wait` once the flag is set will not block.
+        """
+        if not self._value:
+            self._value = True
+
+            for fut in self._waiters:
+                if not fut.done():
+                    fut.set_result(None)
+
+    def clear(self) -> None:
+        """Reset the internal flag to ``False``.
+
+        Calls to `.wait` will block until `.set` is called.
+        """
+        self._value = False
+
+    def wait(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[None]:
+        """Block until the internal flag is true.
+
+        Returns an awaitable, which raises `tornado.util.TimeoutError` after a
+        timeout.
+        """
+        fut = Future()  # type: Future[None]
+        if self._value:
+            fut.set_result(None)
+            return fut
+        self._waiters.add(fut)
+        fut.add_done_callback(lambda fut: self._waiters.remove(fut))
+        if timeout is None:
+            return fut
+        else:
+            timeout_fut = gen.with_timeout(timeout, fut)
+            # This is a slightly clumsy workaround for the fact that
+            # gen.with_timeout doesn't cancel its futures. Cancelling
+            # fut will remove it from the waiters list.
+            timeout_fut.add_done_callback(
+                lambda tf: fut.cancel() if not fut.done() else None
+            )
+            return timeout_fut
+
+
+class _ReleasingContextManager(object):
+    """Releases a Lock or Semaphore at the end of a "with" statement.
+
+    with (yield semaphore.acquire()):
+        pass
+
+    # Now semaphore.release() has been called.
+    """
+
+    def __init__(self, obj: Any) -> None:
+        self._obj = obj
+
+    def __enter__(self) -> None:
+        pass
+
+    def __exit__(
+        self,
+        exc_type: "Optional[Type[BaseException]]",
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[types.TracebackType],
+    ) -> None:
+        self._obj.release()
+
+
+class Semaphore(_TimeoutGarbageCollector):
+    """A lock that can be acquired a fixed number of times before blocking.
+
+    A Semaphore manages a counter representing the number of `.release` calls
+    minus the number of `.acquire` calls, plus an initial value. The `.acquire`
+    method blocks if necessary until it can return without making the counter
+    negative.
+
+    Semaphores limit access to a shared resource. To allow access for two
+    workers at a time:
+
+    .. testsetup:: semaphore
+
+       from collections import deque
+
+       from tornado import gen
+       from tornado.ioloop import IOLoop
+       from tornado.concurrent import Future
+
+       inited = False
+
+       async def simulator(futures):
+           for f in futures:
+               # simulate the asynchronous passage of time
+               await gen.sleep(0)
+               await gen.sleep(0)
+               f.set_result(None)
+
+       def use_some_resource():
+           global inited
+           global futures_q
+           if not inited:
+               inited = True
+               # Ensure reliable doctest output: resolve Futures one at a time.
+               futures_q = deque([Future() for _ in range(3)])
+               IOLoop.current().add_callback(simulator, list(futures_q))
+
+           return futures_q.popleft()
+
+    .. testcode:: semaphore
+
+        import asyncio
+        from tornado import gen
+        from tornado.locks import Semaphore
+
+        sem = Semaphore(2)
+
+        async def worker(worker_id):
+            await sem.acquire()
+            try:
+                print("Worker %d is working" % worker_id)
+                await use_some_resource()
+            finally:
+                print("Worker %d is done" % worker_id)
+                sem.release()
+
+        async def runner():
+            # Join all workers.
+            await gen.multi([worker(i) for i in range(3)])
+
+        asyncio.run(runner())
+
+    .. testoutput:: semaphore
+
+        Worker 0 is working
+        Worker 1 is working
+        Worker 0 is done
+        Worker 2 is working
+        Worker 1 is done
+        Worker 2 is done
+
+    Workers 0 and 1 are allowed to run concurrently, but worker 2 waits until
+    the semaphore has been released once, by worker 0.
+
+    The semaphore can be used as an async context manager::
+
+        async def worker(worker_id):
+            async with sem:
+                print("Worker %d is working" % worker_id)
+                await use_some_resource()
+
+            # Now the semaphore has been released.
+            print("Worker %d is done" % worker_id)
+
+    For compatibility with older versions of Python, `.acquire` is a
+    context manager, so ``worker`` could also be written as::
+
+        @gen.coroutine
+        def worker(worker_id):
+            with (yield sem.acquire()):
+                print("Worker %d is working" % worker_id)
+                yield use_some_resource()
+
+            # Now the semaphore has been released.
+            print("Worker %d is done" % worker_id)
+
+    .. versionchanged:: 4.3
+       Added ``async with`` support in Python 3.5.
+
+    """
+
+    def __init__(self, value: int = 1) -> None:
+        super().__init__()
+        if value < 0:
+            raise ValueError("semaphore initial value must be >= 0")
+
+        self._value = value
+
+    def __repr__(self) -> str:
+        res = super().__repr__()
+        extra = (
+            "locked" if self._value == 0 else "unlocked,value:{0}".format(self._value)
+        )
+        if self._waiters:
+            extra = "{0},waiters:{1}".format(extra, len(self._waiters))
+        return "<{0} [{1}]>".format(res[1:-1], extra)
+
+    def release(self) -> None:
+        """Increment the counter and wake one waiter."""
+        self._value += 1
+        while self._waiters:
+            waiter = self._waiters.popleft()
+            if not waiter.done():
+                self._value -= 1
+
+                # If the waiter is a coroutine paused at
+                #
+                #     with (yield semaphore.acquire()):
+                #
+                # then the context manager's __exit__ calls release() at the end
+                # of the "with" block.
+                waiter.set_result(_ReleasingContextManager(self))
+                break
+
+    def acquire(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[_ReleasingContextManager]:
+        """Decrement the counter. Returns an awaitable.
+
+        Block if the counter is zero and wait for a `.release`. The awaitable
+        raises `.TimeoutError` after the deadline.
+        """
+        waiter = Future()  # type: Future[_ReleasingContextManager]
+        if self._value > 0:
+            self._value -= 1
+            waiter.set_result(_ReleasingContextManager(self))
+        else:
+            self._waiters.append(waiter)
+            if timeout:
+
+                def on_timeout() -> None:
+                    if not waiter.done():
+                        waiter.set_exception(gen.TimeoutError())
+                    self._garbage_collect()
+
+                io_loop = ioloop.IOLoop.current()
+                timeout_handle = io_loop.add_timeout(timeout, on_timeout)
+                waiter.add_done_callback(
+                    lambda _: io_loop.remove_timeout(timeout_handle)
+                )
+        return waiter
+
+    def __enter__(self) -> None:
+        raise RuntimeError("Use 'async with' instead of 'with' for Semaphore")
+
+    def __exit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        traceback: Optional[types.TracebackType],
+    ) -> None:
+        self.__enter__()
+
+    async def __aenter__(self) -> None:
+        await self.acquire()
+
+    async def __aexit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[types.TracebackType],
+    ) -> None:
+        self.release()
+
+
+class BoundedSemaphore(Semaphore):
+    """A semaphore that prevents release() being called too many times.
+
+    If `.release` would increment the semaphore's value past the initial
+    value, it raises `ValueError`. Semaphores are mostly used to guard
+    resources with limited capacity, so a semaphore released too many times
+    is a sign of a bug.
+    """
+
+    def __init__(self, value: int = 1) -> None:
+        super().__init__(value=value)
+        self._initial_value = value
+
+    def release(self) -> None:
+        """Increment the counter and wake one waiter."""
+        if self._value >= self._initial_value:
+            raise ValueError("Semaphore released too many times")
+        super().release()
+
+
+class Lock(object):
+    """A lock for coroutines.
+
+    A Lock begins unlocked, and `acquire` locks it immediately. While it is
+    locked, a coroutine that yields `acquire` waits until another coroutine
+    calls `release`.
+
+    Releasing an unlocked lock raises `RuntimeError`.
+
+    A Lock can be used as an async context manager with the ``async
+    with`` statement:
+
+    >>> from tornado import locks
+    >>> lock = locks.Lock()
+    >>>
+    >>> async def f():
+    ...    async with lock:
+    ...        # Do something holding the lock.
+    ...        pass
+    ...
+    ...    # Now the lock is released.
+
+    For compatibility with older versions of Python, the `.acquire`
+    method asynchronously returns a regular context manager:
+
+    >>> async def f2():
+    ...    with (yield lock.acquire()):
+    ...        # Do something holding the lock.
+    ...        pass
+    ...
+    ...    # Now the lock is released.
+
+    .. versionchanged:: 4.3
+       Added ``async with`` support in Python 3.5.
+
+    """
+
+    def __init__(self) -> None:
+        self._block = BoundedSemaphore(value=1)
+
+    def __repr__(self) -> str:
+        return "<%s _block=%s>" % (self.__class__.__name__, self._block)
+
+    def acquire(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[_ReleasingContextManager]:
+        """Attempt to lock. Returns an awaitable.
+
+        Returns an awaitable, which raises `tornado.util.TimeoutError` after a
+        timeout.
+        """
+        return self._block.acquire(timeout)
+
+    def release(self) -> None:
+        """Unlock.
+
+        The first coroutine in line waiting for `acquire` gets the lock.
+
+        If not locked, raise a `RuntimeError`.
+        """
+        try:
+            self._block.release()
+        except ValueError:
+            raise RuntimeError("release unlocked lock")
+
+    def __enter__(self) -> None:
+        raise RuntimeError("Use `async with` instead of `with` for Lock")
+
+    def __exit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[types.TracebackType],
+    ) -> None:
+        self.__enter__()
+
+    async def __aenter__(self) -> None:
+        await self.acquire()
+
+    async def __aexit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[types.TracebackType],
+    ) -> None:
+        self.release()
diff --git a/venv/lib/python3.9/site-packages/tornado/log.py b/venv/lib/python3.9/site-packages/tornado/log.py
new file mode 100644
index 00000000..86998961
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/log.py
@@ -0,0 +1,343 @@
+#
+# Copyright 2012 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+"""Logging support for Tornado.
+
+Tornado uses three logger streams:
+
+* ``tornado.access``: Per-request logging for Tornado's HTTP servers (and
+  potentially other servers in the future)
+* ``tornado.application``: Logging of errors from application code (i.e.
+  uncaught exceptions from callbacks)
+* ``tornado.general``: General-purpose logging, including any errors
+  or warnings from Tornado itself.
+
+These streams may be configured independently using the standard library's
+`logging` module.  For example, you may wish to send ``tornado.access`` logs
+to a separate file for analysis.
+"""
+import logging
+import logging.handlers
+import sys
+
+from tornado.escape import _unicode
+from tornado.util import unicode_type, basestring_type
+
+try:
+    import colorama  # type: ignore
+except ImportError:
+    colorama = None
+
+try:
+    import curses
+except ImportError:
+    curses = None  # type: ignore
+
+from typing import Dict, Any, cast, Optional
+
+# Logger objects for internal tornado use
+access_log = logging.getLogger("tornado.access")
+app_log = logging.getLogger("tornado.application")
+gen_log = logging.getLogger("tornado.general")
+
+
+def _stderr_supports_color() -> bool:
+    try:
+        if hasattr(sys.stderr, "isatty") and sys.stderr.isatty():
+            if curses:
+                curses.setupterm()
+                if curses.tigetnum("colors") > 0:
+                    return True
+            elif colorama:
+                if sys.stderr is getattr(
+                    colorama.initialise, "wrapped_stderr", object()
+                ):
+                    return True
+    except Exception:
+        # Very broad exception handling because it's always better to
+        # fall back to non-colored logs than to break at startup.
+        pass
+    return False
+
+
+def _safe_unicode(s: Any) -> str:
+    try:
+        return _unicode(s)
+    except UnicodeDecodeError:
+        return repr(s)
+
+
+class LogFormatter(logging.Formatter):
+    """Log formatter used in Tornado.
+
+    Key features of this formatter are:
+
+    * Color support when logging to a terminal that supports it.
+    * Timestamps on every log line.
+    * Robust against str/bytes encoding problems.
+
+    This formatter is enabled automatically by
+    `tornado.options.parse_command_line` or `tornado.options.parse_config_file`
+    (unless ``--logging=none`` is used).
+
+    Color support on Windows versions that do not support ANSI color codes is
+    enabled by use of the colorama__ library. Applications that wish to use
+    this must first initialize colorama with a call to ``colorama.init``.
+    See the colorama documentation for details.
+
+    __ https://pypi.python.org/pypi/colorama
+
+    .. versionchanged:: 4.5
+       Added support for ``colorama``. Changed the constructor
+       signature to be compatible with `logging.config.dictConfig`.
+    """
+
+    DEFAULT_FORMAT = "%(color)s[%(levelname)1.1s %(asctime)s %(module)s:%(lineno)d]%(end_color)s %(message)s"  # noqa: E501
+    DEFAULT_DATE_FORMAT = "%y%m%d %H:%M:%S"
+    DEFAULT_COLORS = {
+        logging.DEBUG: 4,  # Blue
+        logging.INFO: 2,  # Green
+        logging.WARNING: 3,  # Yellow
+        logging.ERROR: 1,  # Red
+        logging.CRITICAL: 5,  # Magenta
+    }
+
+    def __init__(
+        self,
+        fmt: str = DEFAULT_FORMAT,
+        datefmt: str = DEFAULT_DATE_FORMAT,
+        style: str = "%",
+        color: bool = True,
+        colors: Dict[int, int] = DEFAULT_COLORS,
+    ) -> None:
+        r"""
+        :arg bool color: Enables color support.
+        :arg str fmt: Log message format.
+          It will be applied to the attributes dict of log records. The
+          text between ``%(color)s`` and ``%(end_color)s`` will be colored
+          depending on the level if color support is on.
+        :arg dict colors: color mappings from logging level to terminal color
+          code
+        :arg str datefmt: Datetime format.
+          Used for formatting ``(asctime)`` placeholder in ``prefix_fmt``.
+
+        .. versionchanged:: 3.2
+
+           Added ``fmt`` and ``datefmt`` arguments.
+        """
+        logging.Formatter.__init__(self, datefmt=datefmt)
+        self._fmt = fmt
+
+        self._colors = {}  # type: Dict[int, str]
+        if color and _stderr_supports_color():
+            if curses is not None:
+                fg_color = curses.tigetstr("setaf") or curses.tigetstr("setf") or b""
+
+                for levelno, code in colors.items():
+                    # Convert the terminal control characters from
+                    # bytes to unicode strings for easier use with the
+                    # logging module.
+                    self._colors[levelno] = unicode_type(
+                        curses.tparm(fg_color, code), "ascii"
+                    )
+                normal = curses.tigetstr("sgr0")
+                if normal is not None:
+                    self._normal = unicode_type(normal, "ascii")
+                else:
+                    self._normal = ""
+            else:
+                # If curses is not present (currently we'll only get here for
+                # colorama on windows), assume hard-coded ANSI color codes.
+                for levelno, code in colors.items():
+                    self._colors[levelno] = "\033[2;3%dm" % code
+                self._normal = "\033[0m"
+        else:
+            self._normal = ""
+
+    def format(self, record: Any) -> str:
+        try:
+            message = record.getMessage()
+            assert isinstance(message, basestring_type)  # guaranteed by logging
+            # Encoding notes:  The logging module prefers to work with character
+            # strings, but only enforces that log messages are instances of
+            # basestring.  In python 2, non-ascii bytestrings will make
+            # their way through the logging framework until they blow up with
+            # an unhelpful decoding error (with this formatter it happens
+            # when we attach the prefix, but there are other opportunities for
+            # exceptions further along in the framework).
+            #
+            # If a byte string makes it this far, convert it to unicode to
+            # ensure it will make it out to the logs.  Use repr() as a fallback
+            # to ensure that all byte strings can be converted successfully,
+            # but don't do it by default so we don't add extra quotes to ascii
+            # bytestrings.  This is a bit of a hacky place to do this, but
+            # it's worth it since the encoding errors that would otherwise
+            # result are so useless (and tornado is fond of using utf8-encoded
+            # byte strings wherever possible).
+            record.message = _safe_unicode(message)
+        except Exception as e:
+            record.message = "Bad message (%r): %r" % (e, record.__dict__)
+
+        record.asctime = self.formatTime(record, cast(str, self.datefmt))
+
+        if record.levelno in self._colors:
+            record.color = self._colors[record.levelno]
+            record.end_color = self._normal
+        else:
+            record.color = record.end_color = ""
+
+        formatted = self._fmt % record.__dict__
+
+        if record.exc_info:
+            if not record.exc_text:
+                record.exc_text = self.formatException(record.exc_info)
+        if record.exc_text:
+            # exc_text contains multiple lines.  We need to _safe_unicode
+            # each line separately so that non-utf8 bytes don't cause
+            # all the newlines to turn into '\n'.
+            lines = [formatted.rstrip()]
+            lines.extend(_safe_unicode(ln) for ln in record.exc_text.split("\n"))
+            formatted = "\n".join(lines)
+        return formatted.replace("\n", "\n    ")
+
+
+def enable_pretty_logging(
+    options: Any = None, logger: Optional[logging.Logger] = None
+) -> None:
+    """Turns on formatted logging output as configured.
+
+    This is called automatically by `tornado.options.parse_command_line`
+    and `tornado.options.parse_config_file`.
+    """
+    if options is None:
+        import tornado.options
+
+        options = tornado.options.options
+    if options.logging is None or options.logging.lower() == "none":
+        return
+    if logger is None:
+        logger = logging.getLogger()
+    logger.setLevel(getattr(logging, options.logging.upper()))
+    if options.log_file_prefix:
+        rotate_mode = options.log_rotate_mode
+        if rotate_mode == "size":
+            channel = logging.handlers.RotatingFileHandler(
+                filename=options.log_file_prefix,
+                maxBytes=options.log_file_max_size,
+                backupCount=options.log_file_num_backups,
+                encoding="utf-8",
+            )  # type: logging.Handler
+        elif rotate_mode == "time":
+            channel = logging.handlers.TimedRotatingFileHandler(
+                filename=options.log_file_prefix,
+                when=options.log_rotate_when,
+                interval=options.log_rotate_interval,
+                backupCount=options.log_file_num_backups,
+                encoding="utf-8",
+            )
+        else:
+            error_message = (
+                "The value of log_rotate_mode option should be "
+                + '"size" or "time", not "%s".' % rotate_mode
+            )
+            raise ValueError(error_message)
+        channel.setFormatter(LogFormatter(color=False))
+        logger.addHandler(channel)
+
+    if options.log_to_stderr or (options.log_to_stderr is None and not logger.handlers):
+        # Set up color if we are in a tty and curses is installed
+        channel = logging.StreamHandler()
+        channel.setFormatter(LogFormatter())
+        logger.addHandler(channel)
+
+
+def define_logging_options(options: Any = None) -> None:
+    """Add logging-related flags to ``options``.
+
+    These options are present automatically on the default options instance;
+    this method is only necessary if you have created your own `.OptionParser`.
+
+    .. versionadded:: 4.2
+        This function existed in prior versions but was broken and undocumented until 4.2.
+    """
+    if options is None:
+        # late import to prevent cycle
+        import tornado.options
+
+        options = tornado.options.options
+    options.define(
+        "logging",
+        default="info",
+        help=(
+            "Set the Python log level. If 'none', tornado won't touch the "
+            "logging configuration."
+        ),
+        metavar="debug|info|warning|error|none",
+    )
+    options.define(
+        "log_to_stderr",
+        type=bool,
+        default=None,
+        help=(
+            "Send log output to stderr (colorized if possible). "
+            "By default use stderr if --log_file_prefix is not set and "
+            "no other logging is configured."
+        ),
+    )
+    options.define(
+        "log_file_prefix",
+        type=str,
+        default=None,
+        metavar="PATH",
+        help=(
+            "Path prefix for log files. "
+            "Note that if you are running multiple tornado processes, "
+            "log_file_prefix must be different for each of them (e.g. "
+            "include the port number)"
+        ),
+    )
+    options.define(
+        "log_file_max_size",
+        type=int,
+        default=100 * 1000 * 1000,
+        help="max size of log files before rollover",
+    )
+    options.define(
+        "log_file_num_backups", type=int, default=10, help="number of log files to keep"
+    )
+
+    options.define(
+        "log_rotate_when",
+        type=str,
+        default="midnight",
+        help=(
+            "specify the type of TimedRotatingFileHandler interval "
+            "other options:('S', 'M', 'H', 'D', 'W0'-'W6')"
+        ),
+    )
+    options.define(
+        "log_rotate_interval",
+        type=int,
+        default=1,
+        help="The interval value of timed rotating",
+    )
+
+    options.define(
+        "log_rotate_mode",
+        type=str,
+        default="size",
+        help="The mode of rotating files(time or size)",
+    )
+
+    options.add_parse_callback(lambda: enable_pretty_logging(options))
diff --git a/venv/lib/python3.9/site-packages/tornado/netutil.py b/venv/lib/python3.9/site-packages/tornado/netutil.py
new file mode 100644
index 00000000..04db085a
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/netutil.py
@@ -0,0 +1,677 @@
+#
+# Copyright 2011 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Miscellaneous network utility code."""
+
+import asyncio
+import concurrent.futures
+import errno
+import os
+import sys
+import socket
+import ssl
+import stat
+
+from tornado.concurrent import dummy_executor, run_on_executor
+from tornado.ioloop import IOLoop
+from tornado.util import Configurable, errno_from_exception
+
+from typing import List, Callable, Any, Type, Dict, Union, Tuple, Awaitable, Optional
+
+# Note that the naming of ssl.Purpose is confusing; the purpose
+# of a context is to authenticate the opposite side of the connection.
+_client_ssl_defaults = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
+_server_ssl_defaults = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+if hasattr(ssl, "OP_NO_COMPRESSION"):
+    # See netutil.ssl_options_to_context
+    _client_ssl_defaults.options |= ssl.OP_NO_COMPRESSION
+    _server_ssl_defaults.options |= ssl.OP_NO_COMPRESSION
+
+# ThreadedResolver runs getaddrinfo on a thread. If the hostname is unicode,
+# getaddrinfo attempts to import encodings.idna. If this is done at
+# module-import time, the import lock is already held by the main thread,
+# leading to deadlock. Avoid it by caching the idna encoder on the main
+# thread now.
+"foo".encode("idna")
+
+# For undiagnosed reasons, 'latin1' codec may also need to be preloaded.
+"foo".encode("latin1")
+
+# Default backlog used when calling sock.listen()
+_DEFAULT_BACKLOG = 128
+
+
+def bind_sockets(
+    port: int,
+    address: Optional[str] = None,
+    family: socket.AddressFamily = socket.AF_UNSPEC,
+    backlog: int = _DEFAULT_BACKLOG,
+    flags: Optional[int] = None,
+    reuse_port: bool = False,
+) -> List[socket.socket]:
+    """Creates listening sockets bound to the given port and address.
+
+    Returns a list of socket objects (multiple sockets are returned if
+    the given address maps to multiple IP addresses, which is most common
+    for mixed IPv4 and IPv6 use).
+
+    Address may be either an IP address or hostname.  If it's a hostname,
+    the server will listen on all IP addresses associated with the
+    name.  Address may be an empty string or None to listen on all
+    available interfaces.  Family may be set to either `socket.AF_INET`
+    or `socket.AF_INET6` to restrict to IPv4 or IPv6 addresses, otherwise
+    both will be used if available.
+
+    The ``backlog`` argument has the same meaning as for
+    `socket.listen() <socket.socket.listen>`.
+
+    ``flags`` is a bitmask of AI_* flags to `~socket.getaddrinfo`, like
+    ``socket.AI_PASSIVE | socket.AI_NUMERICHOST``.
+
+    ``reuse_port`` option sets ``SO_REUSEPORT`` option for every socket
+    in the list. If your platform doesn't support this option ValueError will
+    be raised.
+    """
+    if reuse_port and not hasattr(socket, "SO_REUSEPORT"):
+        raise ValueError("the platform doesn't support SO_REUSEPORT")
+
+    sockets = []
+    if address == "":
+        address = None
+    if not socket.has_ipv6 and family == socket.AF_UNSPEC:
+        # Python can be compiled with --disable-ipv6, which causes
+        # operations on AF_INET6 sockets to fail, but does not
+        # automatically exclude those results from getaddrinfo
+        # results.
+        # http://bugs.python.org/issue16208
+        family = socket.AF_INET
+    if flags is None:
+        flags = socket.AI_PASSIVE
+    bound_port = None
+    unique_addresses = set()  # type: set
+    for res in sorted(
+        socket.getaddrinfo(address, port, family, socket.SOCK_STREAM, 0, flags),
+        key=lambda x: x[0],
+    ):
+        if res in unique_addresses:
+            continue
+
+        unique_addresses.add(res)
+
+        af, socktype, proto, canonname, sockaddr = res
+        if (
+            sys.platform == "darwin"
+            and address == "localhost"
+            and af == socket.AF_INET6
+            and sockaddr[3] != 0  # type: ignore
+        ):
+            # Mac OS X includes a link-local address fe80::1%lo0 in the
+            # getaddrinfo results for 'localhost'.  However, the firewall
+            # doesn't understand that this is a local address and will
+            # prompt for access (often repeatedly, due to an apparent
+            # bug in its ability to remember granting access to an
+            # application). Skip these addresses.
+            continue
+        try:
+            sock = socket.socket(af, socktype, proto)
+        except socket.error as e:
+            if errno_from_exception(e) == errno.EAFNOSUPPORT:
+                continue
+            raise
+        if os.name != "nt":
+            try:
+                sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            except socket.error as e:
+                if errno_from_exception(e) != errno.ENOPROTOOPT:
+                    # Hurd doesn't support SO_REUSEADDR.
+                    raise
+        if reuse_port:
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+        if af == socket.AF_INET6:
+            # On linux, ipv6 sockets accept ipv4 too by default,
+            # but this makes it impossible to bind to both
+            # 0.0.0.0 in ipv4 and :: in ipv6.  On other systems,
+            # separate sockets *must* be used to listen for both ipv4
+            # and ipv6.  For consistency, always disable ipv4 on our
+            # ipv6 sockets and use a separate ipv4 socket when needed.
+            #
+            # Python 2.x on windows doesn't have IPPROTO_IPV6.
+            if hasattr(socket, "IPPROTO_IPV6"):
+                sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1)
+
+        # automatic port allocation with port=None
+        # should bind on the same port on IPv4 and IPv6
+        host, requested_port = sockaddr[:2]
+        if requested_port == 0 and bound_port is not None:
+            sockaddr = tuple([host, bound_port] + list(sockaddr[2:]))
+
+        sock.setblocking(False)
+        try:
+            sock.bind(sockaddr)
+        except OSError as e:
+            if (
+                errno_from_exception(e) == errno.EADDRNOTAVAIL
+                and address == "localhost"
+                and sockaddr[0] == "::1"
+            ):
+                # On some systems (most notably docker with default
+                # configurations), ipv6 is partially disabled:
+                # socket.has_ipv6 is true, we can create AF_INET6
+                # sockets, and getaddrinfo("localhost", ...,
+                # AF_PASSIVE) resolves to ::1, but we get an error
+                # when binding.
+                #
+                # Swallow the error, but only for this specific case.
+                # If EADDRNOTAVAIL occurs in other situations, it
+                # might be a real problem like a typo in a
+                # configuration.
+                sock.close()
+                continue
+            else:
+                raise
+        bound_port = sock.getsockname()[1]
+        sock.listen(backlog)
+        sockets.append(sock)
+    return sockets
+
+
+if hasattr(socket, "AF_UNIX"):
+
+    def bind_unix_socket(
+        file: str, mode: int = 0o600, backlog: int = _DEFAULT_BACKLOG
+    ) -> socket.socket:
+        """Creates a listening unix socket.
+
+        If a socket with the given name already exists, it will be deleted.
+        If any other file with that name exists, an exception will be
+        raised.
+
+        Returns a socket object (not a list of socket objects like
+        `bind_sockets`)
+        """
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        try:
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        except socket.error as e:
+            if errno_from_exception(e) != errno.ENOPROTOOPT:
+                # Hurd doesn't support SO_REUSEADDR
+                raise
+        sock.setblocking(False)
+        try:
+            st = os.stat(file)
+        except FileNotFoundError:
+            pass
+        else:
+            if stat.S_ISSOCK(st.st_mode):
+                os.remove(file)
+            else:
+                raise ValueError("File %s exists and is not a socket", file)
+        sock.bind(file)
+        os.chmod(file, mode)
+        sock.listen(backlog)
+        return sock
+
+
+def add_accept_handler(
+    sock: socket.socket, callback: Callable[[socket.socket, Any], None]
+) -> Callable[[], None]:
+    """Adds an `.IOLoop` event handler to accept new connections on ``sock``.
+
+    When a connection is accepted, ``callback(connection, address)`` will
+    be run (``connection`` is a socket object, and ``address`` is the
+    address of the other end of the connection).  Note that this signature
+    is different from the ``callback(fd, events)`` signature used for
+    `.IOLoop` handlers.
+
+    A callable is returned which, when called, will remove the `.IOLoop`
+    event handler and stop processing further incoming connections.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. versionchanged:: 5.0
+       A callable is returned (``None`` was returned before).
+    """
+    io_loop = IOLoop.current()
+    removed = [False]
+
+    def accept_handler(fd: socket.socket, events: int) -> None:
+        # More connections may come in while we're handling callbacks;
+        # to prevent starvation of other tasks we must limit the number
+        # of connections we accept at a time.  Ideally we would accept
+        # up to the number of connections that were waiting when we
+        # entered this method, but this information is not available
+        # (and rearranging this method to call accept() as many times
+        # as possible before running any callbacks would have adverse
+        # effects on load balancing in multiprocess configurations).
+        # Instead, we use the (default) listen backlog as a rough
+        # heuristic for the number of connections we can reasonably
+        # accept at once.
+        for i in range(_DEFAULT_BACKLOG):
+            if removed[0]:
+                # The socket was probably closed
+                return
+            try:
+                connection, address = sock.accept()
+            except BlockingIOError:
+                # EWOULDBLOCK indicates we have accepted every
+                # connection that is available.
+                return
+            except ConnectionAbortedError:
+                # ECONNABORTED indicates that there was a connection
+                # but it was closed while still in the accept queue.
+                # (observed on FreeBSD).
+                continue
+            callback(connection, address)
+
+    def remove_handler() -> None:
+        io_loop.remove_handler(sock)
+        removed[0] = True
+
+    io_loop.add_handler(sock, accept_handler, IOLoop.READ)
+    return remove_handler
+
+
+def is_valid_ip(ip: str) -> bool:
+    """Returns ``True`` if the given string is a well-formed IP address.
+
+    Supports IPv4 and IPv6.
+    """
+    if not ip or "\x00" in ip:
+        # getaddrinfo resolves empty strings to localhost, and truncates
+        # on zero bytes.
+        return False
+    try:
+        res = socket.getaddrinfo(
+            ip, 0, socket.AF_UNSPEC, socket.SOCK_STREAM, 0, socket.AI_NUMERICHOST
+        )
+        return bool(res)
+    except socket.gaierror as e:
+        if e.args[0] == socket.EAI_NONAME:
+            return False
+        raise
+    except UnicodeError:
+        # `socket.getaddrinfo` will raise a UnicodeError from the
+        # `idna` decoder if the input is longer than 63 characters,
+        # even for socket.AI_NUMERICHOST.  See
+        # https://bugs.python.org/issue32958 for discussion
+        return False
+    return True
+
+
+class Resolver(Configurable):
+    """Configurable asynchronous DNS resolver interface.
+
+    By default, a blocking implementation is used (which simply calls
+    `socket.getaddrinfo`).  An alternative implementation can be
+    chosen with the `Resolver.configure <.Configurable.configure>`
+    class method::
+
+        Resolver.configure('tornado.netutil.ThreadedResolver')
+
+    The implementations of this interface included with Tornado are
+
+    * `tornado.netutil.DefaultLoopResolver`
+    * `tornado.netutil.DefaultExecutorResolver` (deprecated)
+    * `tornado.netutil.BlockingResolver` (deprecated)
+    * `tornado.netutil.ThreadedResolver` (deprecated)
+    * `tornado.netutil.OverrideResolver`
+    * `tornado.platform.twisted.TwistedResolver` (deprecated)
+    * `tornado.platform.caresresolver.CaresResolver` (deprecated)
+
+    .. versionchanged:: 5.0
+       The default implementation has changed from `BlockingResolver` to
+       `DefaultExecutorResolver`.
+
+    .. versionchanged:: 6.2
+       The default implementation has changed from `DefaultExecutorResolver` to
+       `DefaultLoopResolver`.
+    """
+
+    @classmethod
+    def configurable_base(cls) -> Type["Resolver"]:
+        return Resolver
+
+    @classmethod
+    def configurable_default(cls) -> Type["Resolver"]:
+        return DefaultLoopResolver
+
+    def resolve(
+        self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+    ) -> Awaitable[List[Tuple[int, Any]]]:
+        """Resolves an address.
+
+        The ``host`` argument is a string which may be a hostname or a
+        literal IP address.
+
+        Returns a `.Future` whose result is a list of (family,
+        address) pairs, where address is a tuple suitable to pass to
+        `socket.connect <socket.socket.connect>` (i.e. a ``(host,
+        port)`` pair for IPv4; additional fields may be present for
+        IPv6). If a ``callback`` is passed, it will be run with the
+        result as an argument when it is complete.
+
+        :raises IOError: if the address cannot be resolved.
+
+        .. versionchanged:: 4.4
+           Standardized all implementations to raise `IOError`.
+
+        .. versionchanged:: 6.0 The ``callback`` argument was removed.
+           Use the returned awaitable object instead.
+
+        """
+        raise NotImplementedError()
+
+    def close(self) -> None:
+        """Closes the `Resolver`, freeing any resources used.
+
+        .. versionadded:: 3.1
+
+        """
+        pass
+
+
+def _resolve_addr(
+    host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+) -> List[Tuple[int, Any]]:
+    # On Solaris, getaddrinfo fails if the given port is not found
+    # in /etc/services and no socket type is given, so we must pass
+    # one here.  The socket type used here doesn't seem to actually
+    # matter (we discard the one we get back in the results),
+    # so the addresses we return should still be usable with SOCK_DGRAM.
+    addrinfo = socket.getaddrinfo(host, port, family, socket.SOCK_STREAM)
+    results = []
+    for fam, socktype, proto, canonname, address in addrinfo:
+        results.append((fam, address))
+    return results  # type: ignore
+
+
+class DefaultExecutorResolver(Resolver):
+    """Resolver implementation using `.IOLoop.run_in_executor`.
+
+    .. versionadded:: 5.0
+
+    .. deprecated:: 6.2
+
+       Use `DefaultLoopResolver` instead.
+    """
+
+    async def resolve(
+        self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+    ) -> List[Tuple[int, Any]]:
+        result = await IOLoop.current().run_in_executor(
+            None, _resolve_addr, host, port, family
+        )
+        return result
+
+
+class DefaultLoopResolver(Resolver):
+    """Resolver implementation using `asyncio.loop.getaddrinfo`."""
+
+    async def resolve(
+        self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+    ) -> List[Tuple[int, Any]]:
+        # On Solaris, getaddrinfo fails if the given port is not found
+        # in /etc/services and no socket type is given, so we must pass
+        # one here.  The socket type used here doesn't seem to actually
+        # matter (we discard the one we get back in the results),
+        # so the addresses we return should still be usable with SOCK_DGRAM.
+        return [
+            (fam, address)
+            for fam, _, _, _, address in await asyncio.get_running_loop().getaddrinfo(
+                host, port, family=family, type=socket.SOCK_STREAM
+            )
+        ]
+
+
+class ExecutorResolver(Resolver):
+    """Resolver implementation using a `concurrent.futures.Executor`.
+
+    Use this instead of `ThreadedResolver` when you require additional
+    control over the executor being used.
+
+    The executor will be shut down when the resolver is closed unless
+    ``close_resolver=False``; use this if you want to reuse the same
+    executor elsewhere.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. deprecated:: 5.0
+       The default `Resolver` now uses `asyncio.loop.getaddrinfo`;
+       use that instead of this class.
+    """
+
+    def initialize(
+        self,
+        executor: Optional[concurrent.futures.Executor] = None,
+        close_executor: bool = True,
+    ) -> None:
+        if executor is not None:
+            self.executor = executor
+            self.close_executor = close_executor
+        else:
+            self.executor = dummy_executor
+            self.close_executor = False
+
+    def close(self) -> None:
+        if self.close_executor:
+            self.executor.shutdown()
+        self.executor = None  # type: ignore
+
+    @run_on_executor
+    def resolve(
+        self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+    ) -> List[Tuple[int, Any]]:
+        return _resolve_addr(host, port, family)
+
+
+class BlockingResolver(ExecutorResolver):
+    """Default `Resolver` implementation, using `socket.getaddrinfo`.
+
+    The `.IOLoop` will be blocked during the resolution, although the
+    callback will not be run until the next `.IOLoop` iteration.
+
+    .. deprecated:: 5.0
+       The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead
+       of this class.
+    """
+
+    def initialize(self) -> None:  # type: ignore
+        super().initialize()
+
+
+class ThreadedResolver(ExecutorResolver):
+    """Multithreaded non-blocking `Resolver` implementation.
+
+    Requires the `concurrent.futures` package to be installed
+    (available in the standard library since Python 3.2,
+    installable with ``pip install futures`` in older versions).
+
+    The thread pool size can be configured with::
+
+        Resolver.configure('tornado.netutil.ThreadedResolver',
+                           num_threads=10)
+
+    .. versionchanged:: 3.1
+       All ``ThreadedResolvers`` share a single thread pool, whose
+       size is set by the first one to be created.
+
+    .. deprecated:: 5.0
+       The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead
+       of this class.
+    """
+
+    _threadpool = None  # type: ignore
+    _threadpool_pid = None  # type: int
+
+    def initialize(self, num_threads: int = 10) -> None:  # type: ignore
+        threadpool = ThreadedResolver._create_threadpool(num_threads)
+        super().initialize(executor=threadpool, close_executor=False)
+
+    @classmethod
+    def _create_threadpool(
+        cls, num_threads: int
+    ) -> concurrent.futures.ThreadPoolExecutor:
+        pid = os.getpid()
+        if cls._threadpool_pid != pid:
+            # Threads cannot survive after a fork, so if our pid isn't what it
+            # was when we created the pool then delete it.
+            cls._threadpool = None
+        if cls._threadpool is None:
+            cls._threadpool = concurrent.futures.ThreadPoolExecutor(num_threads)
+            cls._threadpool_pid = pid
+        return cls._threadpool
+
+
+class OverrideResolver(Resolver):
+    """Wraps a resolver with a mapping of overrides.
+
+    This can be used to make local DNS changes (e.g. for testing)
+    without modifying system-wide settings.
+
+    The mapping can be in three formats::
+
+        {
+            # Hostname to host or ip
+            "example.com": "127.0.1.1",
+
+            # Host+port to host+port
+            ("login.example.com", 443): ("localhost", 1443),
+
+            # Host+port+address family to host+port
+            ("login.example.com", 443, socket.AF_INET6): ("::1", 1443),
+        }
+
+    .. versionchanged:: 5.0
+       Added support for host-port-family triplets.
+    """
+
+    def initialize(self, resolver: Resolver, mapping: dict) -> None:
+        self.resolver = resolver
+        self.mapping = mapping
+
+    def close(self) -> None:
+        self.resolver.close()
+
+    def resolve(
+        self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
+    ) -> Awaitable[List[Tuple[int, Any]]]:
+        if (host, port, family) in self.mapping:
+            host, port = self.mapping[(host, port, family)]
+        elif (host, port) in self.mapping:
+            host, port = self.mapping[(host, port)]
+        elif host in self.mapping:
+            host = self.mapping[host]
+        return self.resolver.resolve(host, port, family)
+
+
+# These are the keyword arguments to ssl.wrap_socket that must be translated
+# to their SSLContext equivalents (the other arguments are still passed
+# to SSLContext.wrap_socket).
+_SSL_CONTEXT_KEYWORDS = frozenset(
+    ["ssl_version", "certfile", "keyfile", "cert_reqs", "ca_certs", "ciphers"]
+)
+
+
+def ssl_options_to_context(
+    ssl_options: Union[Dict[str, Any], ssl.SSLContext],
+    server_side: Optional[bool] = None,
+) -> ssl.SSLContext:
+    """Try to convert an ``ssl_options`` dictionary to an
+    `~ssl.SSLContext` object.
+
+    The ``ssl_options`` dictionary contains keywords to be passed to
+    `ssl.wrap_socket`.  In Python 2.7.9+, `ssl.SSLContext` objects can
+    be used instead.  This function converts the dict form to its
+    `~ssl.SSLContext` equivalent, and may be used when a component which
+    accepts both forms needs to upgrade to the `~ssl.SSLContext` version
+    to use features like SNI or NPN.
+
+    .. versionchanged:: 6.2
+
+       Added server_side argument. Omitting this argument will
+       result in a DeprecationWarning on Python 3.10.
+
+    """
+    if isinstance(ssl_options, ssl.SSLContext):
+        return ssl_options
+    assert isinstance(ssl_options, dict)
+    assert all(k in _SSL_CONTEXT_KEYWORDS for k in ssl_options), ssl_options
+    # TODO: Now that we have the server_side argument, can we switch to
+    # create_default_context or would that change behavior?
+    default_version = ssl.PROTOCOL_TLS
+    if server_side:
+        default_version = ssl.PROTOCOL_TLS_SERVER
+    elif server_side is not None:
+        default_version = ssl.PROTOCOL_TLS_CLIENT
+    context = ssl.SSLContext(ssl_options.get("ssl_version", default_version))
+    if "certfile" in ssl_options:
+        context.load_cert_chain(
+            ssl_options["certfile"], ssl_options.get("keyfile", None)
+        )
+    if "cert_reqs" in ssl_options:
+        if ssl_options["cert_reqs"] == ssl.CERT_NONE:
+            # This may have been set automatically by PROTOCOL_TLS_CLIENT but is
+            # incompatible with CERT_NONE so we must manually clear it.
+            context.check_hostname = False
+        context.verify_mode = ssl_options["cert_reqs"]
+    if "ca_certs" in ssl_options:
+        context.load_verify_locations(ssl_options["ca_certs"])
+    if "ciphers" in ssl_options:
+        context.set_ciphers(ssl_options["ciphers"])
+    if hasattr(ssl, "OP_NO_COMPRESSION"):
+        # Disable TLS compression to avoid CRIME and related attacks.
+        # This constant depends on openssl version 1.0.
+        # TODO: Do we need to do this ourselves or can we trust
+        # the defaults?
+        context.options |= ssl.OP_NO_COMPRESSION
+    return context
+
+
+def ssl_wrap_socket(
+    socket: socket.socket,
+    ssl_options: Union[Dict[str, Any], ssl.SSLContext],
+    server_hostname: Optional[str] = None,
+    server_side: Optional[bool] = None,
+    **kwargs: Any
+) -> ssl.SSLSocket:
+    """Returns an ``ssl.SSLSocket`` wrapping the given socket.
+
+    ``ssl_options`` may be either an `ssl.SSLContext` object or a
+    dictionary (as accepted by `ssl_options_to_context`).  Additional
+    keyword arguments are passed to ``wrap_socket`` (either the
+    `~ssl.SSLContext` method or the `ssl` module function as
+    appropriate).
+
+    .. versionchanged:: 6.2
+
+       Added server_side argument. Omitting this argument will
+       result in a DeprecationWarning on Python 3.10.
+    """
+    context = ssl_options_to_context(ssl_options, server_side=server_side)
+    if server_side is None:
+        server_side = False
+    if ssl.HAS_SNI:
+        # In python 3.4, wrap_socket only accepts the server_hostname
+        # argument if HAS_SNI is true.
+        # TODO: add a unittest (python added server-side SNI support in 3.4)
+        # In the meantime it can be manually tested with
+        # python3 -m tornado.httpclient https://sni.velox.ch
+        return context.wrap_socket(
+            socket, server_hostname=server_hostname, server_side=server_side, **kwargs
+        )
+    else:
+        return context.wrap_socket(socket, server_side=server_side, **kwargs)
diff --git a/venv/lib/python3.9/site-packages/tornado/options.py b/venv/lib/python3.9/site-packages/tornado/options.py
new file mode 100644
index 00000000..b8296691
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/options.py
@@ -0,0 +1,750 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""A command line parsing module that lets modules define their own options.
+
+This module is inspired by Google's `gflags
+<https://github.com/google/python-gflags>`_. The primary difference
+with libraries such as `argparse` is that a global registry is used so
+that options may be defined in any module (it also enables
+`tornado.log` by default). The rest of Tornado does not depend on this
+module, so feel free to use `argparse` or other configuration
+libraries if you prefer them.
+
+Options must be defined with `tornado.options.define` before use,
+generally at the top level of a module. The options are then
+accessible as attributes of `tornado.options.options`::
+
+    # myapp/db.py
+    from tornado.options import define, options
+
+    define("mysql_host", default="127.0.0.1:3306", help="Main user DB")
+    define("memcache_hosts", default="127.0.0.1:11011", multiple=True,
+           help="Main user memcache servers")
+
+    def connect():
+        db = database.Connection(options.mysql_host)
+        ...
+
+    # myapp/server.py
+    from tornado.options import define, options
+
+    define("port", default=8080, help="port to listen on")
+
+    def start_server():
+        app = make_app()
+        app.listen(options.port)
+
+The ``main()`` method of your application does not need to be aware of all of
+the options used throughout your program; they are all automatically loaded
+when the modules are loaded.  However, all modules that define options
+must have been imported before the command line is parsed.
+
+Your ``main()`` method can parse the command line or parse a config file with
+either `parse_command_line` or `parse_config_file`::
+
+    import myapp.db, myapp.server
+    import tornado
+
+    if __name__ == '__main__':
+        tornado.options.parse_command_line()
+        # or
+        tornado.options.parse_config_file("/etc/server.conf")
+
+.. note::
+
+   When using multiple ``parse_*`` functions, pass ``final=False`` to all
+   but the last one, or side effects may occur twice (in particular,
+   this can result in log messages being doubled).
+
+`tornado.options.options` is a singleton instance of `OptionParser`, and
+the top-level functions in this module (`define`, `parse_command_line`, etc)
+simply call methods on it.  You may create additional `OptionParser`
+instances to define isolated sets of options, such as for subcommands.
+
+.. note::
+
+   By default, several options are defined that will configure the
+   standard `logging` module when `parse_command_line` or `parse_config_file`
+   are called.  If you want Tornado to leave the logging configuration
+   alone so you can manage it yourself, either pass ``--logging=none``
+   on the command line or do the following to disable it in code::
+
+       from tornado.options import options, parse_command_line
+       options.logging = None
+       parse_command_line()
+
+.. note::
+
+   `parse_command_line` or `parse_config_file` function should called after
+   logging configuration and user-defined command line flags using the
+   ``callback`` option definition, or these configurations will not take effect.
+
+.. versionchanged:: 4.3
+   Dashes and underscores are fully interchangeable in option names;
+   options can be defined, set, and read with any mix of the two.
+   Dashes are typical for command-line usage while config files require
+   underscores.
+"""
+
+import datetime
+import numbers
+import re
+import sys
+import os
+import textwrap
+
+from tornado.escape import _unicode, native_str
+from tornado.log import define_logging_options
+from tornado.util import basestring_type, exec_in
+
+from typing import (
+    Any,
+    Iterator,
+    Iterable,
+    Tuple,
+    Set,
+    Dict,
+    Callable,
+    List,
+    TextIO,
+    Optional,
+)
+
+
+class Error(Exception):
+    """Exception raised by errors in the options module."""
+
+    pass
+
+
+class OptionParser(object):
+    """A collection of options, a dictionary with object-like access.
+
+    Normally accessed via static functions in the `tornado.options` module,
+    which reference a global instance.
+    """
+
+    def __init__(self) -> None:
+        # we have to use self.__dict__ because we override setattr.
+        self.__dict__["_options"] = {}
+        self.__dict__["_parse_callbacks"] = []
+        self.define(
+            "help",
+            type=bool,
+            help="show this help information",
+            callback=self._help_callback,
+        )
+
+    def _normalize_name(self, name: str) -> str:
+        return name.replace("_", "-")
+
+    def __getattr__(self, name: str) -> Any:
+        name = self._normalize_name(name)
+        if isinstance(self._options.get(name), _Option):
+            return self._options[name].value()
+        raise AttributeError("Unrecognized option %r" % name)
+
+    def __setattr__(self, name: str, value: Any) -> None:
+        name = self._normalize_name(name)
+        if isinstance(self._options.get(name), _Option):
+            return self._options[name].set(value)
+        raise AttributeError("Unrecognized option %r" % name)
+
+    def __iter__(self) -> Iterator:
+        return (opt.name for opt in self._options.values())
+
+    def __contains__(self, name: str) -> bool:
+        name = self._normalize_name(name)
+        return name in self._options
+
+    def __getitem__(self, name: str) -> Any:
+        return self.__getattr__(name)
+
+    def __setitem__(self, name: str, value: Any) -> None:
+        return self.__setattr__(name, value)
+
+    def items(self) -> Iterable[Tuple[str, Any]]:
+        """An iterable of (name, value) pairs.
+
+        .. versionadded:: 3.1
+        """
+        return [(opt.name, opt.value()) for name, opt in self._options.items()]
+
+    def groups(self) -> Set[str]:
+        """The set of option-groups created by ``define``.
+
+        .. versionadded:: 3.1
+        """
+        return set(opt.group_name for opt in self._options.values())
+
+    def group_dict(self, group: str) -> Dict[str, Any]:
+        """The names and values of options in a group.
+
+        Useful for copying options into Application settings::
+
+            from tornado.options import define, parse_command_line, options
+
+            define('template_path', group='application')
+            define('static_path', group='application')
+
+            parse_command_line()
+
+            application = Application(
+                handlers, **options.group_dict('application'))
+
+        .. versionadded:: 3.1
+        """
+        return dict(
+            (opt.name, opt.value())
+            for name, opt in self._options.items()
+            if not group or group == opt.group_name
+        )
+
+    def as_dict(self) -> Dict[str, Any]:
+        """The names and values of all options.
+
+        .. versionadded:: 3.1
+        """
+        return dict((opt.name, opt.value()) for name, opt in self._options.items())
+
+    def define(
+        self,
+        name: str,
+        default: Any = None,
+        type: Optional[type] = None,
+        help: Optional[str] = None,
+        metavar: Optional[str] = None,
+        multiple: bool = False,
+        group: Optional[str] = None,
+        callback: Optional[Callable[[Any], None]] = None,
+    ) -> None:
+        """Defines a new command line option.
+
+        ``type`` can be any of `str`, `int`, `float`, `bool`,
+        `~datetime.datetime`, or `~datetime.timedelta`. If no ``type``
+        is given but a ``default`` is, ``type`` is the type of
+        ``default``. Otherwise, ``type`` defaults to `str`.
+
+        If ``multiple`` is True, the option value is a list of ``type``
+        instead of an instance of ``type``.
+
+        ``help`` and ``metavar`` are used to construct the
+        automatically generated command line help string. The help
+        message is formatted like::
+
+           --name=METAVAR      help string
+
+        ``group`` is used to group the defined options in logical
+        groups. By default, command line options are grouped by the
+        file in which they are defined.
+
+        Command line option names must be unique globally.
+
+        If a ``callback`` is given, it will be run with the new value whenever
+        the option is changed.  This can be used to combine command-line
+        and file-based options::
+
+            define("config", type=str, help="path to config file",
+                   callback=lambda path: parse_config_file(path, final=False))
+
+        With this definition, options in the file specified by ``--config`` will
+        override options set earlier on the command line, but can be overridden
+        by later flags.
+
+        """
+        normalized = self._normalize_name(name)
+        if normalized in self._options:
+            raise Error(
+                "Option %r already defined in %s"
+                % (normalized, self._options[normalized].file_name)
+            )
+        frame = sys._getframe(0)
+        if frame is not None:
+            options_file = frame.f_code.co_filename
+
+            # Can be called directly, or through top level define() fn, in which
+            # case, step up above that frame to look for real caller.
+            if (
+                frame.f_back is not None
+                and frame.f_back.f_code.co_filename == options_file
+                and frame.f_back.f_code.co_name == "define"
+            ):
+                frame = frame.f_back
+
+            assert frame.f_back is not None
+            file_name = frame.f_back.f_code.co_filename
+        else:
+            file_name = "<unknown>"
+        if file_name == options_file:
+            file_name = ""
+        if type is None:
+            if not multiple and default is not None:
+                type = default.__class__
+            else:
+                type = str
+        if group:
+            group_name = group  # type: Optional[str]
+        else:
+            group_name = file_name
+        option = _Option(
+            name,
+            file_name=file_name,
+            default=default,
+            type=type,
+            help=help,
+            metavar=metavar,
+            multiple=multiple,
+            group_name=group_name,
+            callback=callback,
+        )
+        self._options[normalized] = option
+
+    def parse_command_line(
+        self, args: Optional[List[str]] = None, final: bool = True
+    ) -> List[str]:
+        """Parses all options given on the command line (defaults to
+        `sys.argv`).
+
+        Options look like ``--option=value`` and are parsed according
+        to their ``type``. For boolean options, ``--option`` is
+        equivalent to ``--option=true``
+
+        If the option has ``multiple=True``, comma-separated values
+        are accepted. For multi-value integer options, the syntax
+        ``x:y`` is also accepted and equivalent to ``range(x, y)``.
+
+        Note that ``args[0]`` is ignored since it is the program name
+        in `sys.argv`.
+
+        We return a list of all arguments that are not parsed as options.
+
+        If ``final`` is ``False``, parse callbacks will not be run.
+        This is useful for applications that wish to combine configurations
+        from multiple sources.
+
+        """
+        if args is None:
+            args = sys.argv
+        remaining = []  # type: List[str]
+        for i in range(1, len(args)):
+            # All things after the last option are command line arguments
+            if not args[i].startswith("-"):
+                remaining = args[i:]
+                break
+            if args[i] == "--":
+                remaining = args[i + 1 :]
+                break
+            arg = args[i].lstrip("-")
+            name, equals, value = arg.partition("=")
+            name = self._normalize_name(name)
+            if name not in self._options:
+                self.print_help()
+                raise Error("Unrecognized command line option: %r" % name)
+            option = self._options[name]
+            if not equals:
+                if option.type == bool:
+                    value = "true"
+                else:
+                    raise Error("Option %r requires a value" % name)
+            option.parse(value)
+
+        if final:
+            self.run_parse_callbacks()
+
+        return remaining
+
+    def parse_config_file(self, path: str, final: bool = True) -> None:
+        """Parses and loads the config file at the given path.
+
+        The config file contains Python code that will be executed (so
+        it is **not safe** to use untrusted config files). Anything in
+        the global namespace that matches a defined option will be
+        used to set that option's value.
+
+        Options may either be the specified type for the option or
+        strings (in which case they will be parsed the same way as in
+        `.parse_command_line`)
+
+        Example (using the options defined in the top-level docs of
+        this module)::
+
+            port = 80
+            mysql_host = 'mydb.example.com:3306'
+            # Both lists and comma-separated strings are allowed for
+            # multiple=True.
+            memcache_hosts = ['cache1.example.com:11011',
+                              'cache2.example.com:11011']
+            memcache_hosts = 'cache1.example.com:11011,cache2.example.com:11011'
+
+        If ``final`` is ``False``, parse callbacks will not be run.
+        This is useful for applications that wish to combine configurations
+        from multiple sources.
+
+        .. note::
+
+            `tornado.options` is primarily a command-line library.
+            Config file support is provided for applications that wish
+            to use it, but applications that prefer config files may
+            wish to look at other libraries instead.
+
+        .. versionchanged:: 4.1
+           Config files are now always interpreted as utf-8 instead of
+           the system default encoding.
+
+        .. versionchanged:: 4.4
+           The special variable ``__file__`` is available inside config
+           files, specifying the absolute path to the config file itself.
+
+        .. versionchanged:: 5.1
+           Added the ability to set options via strings in config files.
+
+        """
+        config = {"__file__": os.path.abspath(path)}
+        with open(path, "rb") as f:
+            exec_in(native_str(f.read()), config, config)
+        for name in config:
+            normalized = self._normalize_name(name)
+            if normalized in self._options:
+                option = self._options[normalized]
+                if option.multiple:
+                    if not isinstance(config[name], (list, str)):
+                        raise Error(
+                            "Option %r is required to be a list of %s "
+                            "or a comma-separated string"
+                            % (option.name, option.type.__name__)
+                        )
+
+                if type(config[name]) == str and (
+                    option.type != str or option.multiple
+                ):
+                    option.parse(config[name])
+                else:
+                    option.set(config[name])
+
+        if final:
+            self.run_parse_callbacks()
+
+    def print_help(self, file: Optional[TextIO] = None) -> None:
+        """Prints all the command line options to stderr (or another file)."""
+        if file is None:
+            file = sys.stderr
+        print("Usage: %s [OPTIONS]" % sys.argv[0], file=file)
+        print("\nOptions:\n", file=file)
+        by_group = {}  # type: Dict[str, List[_Option]]
+        for option in self._options.values():
+            by_group.setdefault(option.group_name, []).append(option)
+
+        for filename, o in sorted(by_group.items()):
+            if filename:
+                print("\n%s options:\n" % os.path.normpath(filename), file=file)
+            o.sort(key=lambda option: option.name)
+            for option in o:
+                # Always print names with dashes in a CLI context.
+                prefix = self._normalize_name(option.name)
+                if option.metavar:
+                    prefix += "=" + option.metavar
+                description = option.help or ""
+                if option.default is not None and option.default != "":
+                    description += " (default %s)" % option.default
+                lines = textwrap.wrap(description, 79 - 35)
+                if len(prefix) > 30 or len(lines) == 0:
+                    lines.insert(0, "")
+                print("  --%-30s %s" % (prefix, lines[0]), file=file)
+                for line in lines[1:]:
+                    print("%-34s %s" % (" ", line), file=file)
+        print(file=file)
+
+    def _help_callback(self, value: bool) -> None:
+        if value:
+            self.print_help()
+            sys.exit(0)
+
+    def add_parse_callback(self, callback: Callable[[], None]) -> None:
+        """Adds a parse callback, to be invoked when option parsing is done."""
+        self._parse_callbacks.append(callback)
+
+    def run_parse_callbacks(self) -> None:
+        for callback in self._parse_callbacks:
+            callback()
+
+    def mockable(self) -> "_Mockable":
+        """Returns a wrapper around self that is compatible with
+        `mock.patch <unittest.mock.patch>`.
+
+        The `mock.patch <unittest.mock.patch>` function (included in
+        the standard library `unittest.mock` package since Python 3.3,
+        or in the third-party ``mock`` package for older versions of
+        Python) is incompatible with objects like ``options`` that
+        override ``__getattr__`` and ``__setattr__``.  This function
+        returns an object that can be used with `mock.patch.object
+        <unittest.mock.patch.object>` to modify option values::
+
+            with mock.patch.object(options.mockable(), 'name', value):
+                assert options.name == value
+        """
+        return _Mockable(self)
+
+
+class _Mockable(object):
+    """`mock.patch` compatible wrapper for `OptionParser`.
+
+    As of ``mock`` version 1.0.1, when an object uses ``__getattr__``
+    hooks instead of ``__dict__``, ``patch.__exit__`` tries to delete
+    the attribute it set instead of setting a new one (assuming that
+    the object does not capture ``__setattr__``, so the patch
+    created a new attribute in ``__dict__``).
+
+    _Mockable's getattr and setattr pass through to the underlying
+    OptionParser, and delattr undoes the effect of a previous setattr.
+    """
+
+    def __init__(self, options: OptionParser) -> None:
+        # Modify __dict__ directly to bypass __setattr__
+        self.__dict__["_options"] = options
+        self.__dict__["_originals"] = {}
+
+    def __getattr__(self, name: str) -> Any:
+        return getattr(self._options, name)
+
+    def __setattr__(self, name: str, value: Any) -> None:
+        assert name not in self._originals, "don't reuse mockable objects"
+        self._originals[name] = getattr(self._options, name)
+        setattr(self._options, name, value)
+
+    def __delattr__(self, name: str) -> None:
+        setattr(self._options, name, self._originals.pop(name))
+
+
+class _Option(object):
+    # This class could almost be made generic, but the way the types
+    # interact with the multiple argument makes this tricky. (default
+    # and the callback use List[T], but type is still Type[T]).
+    UNSET = object()
+
+    def __init__(
+        self,
+        name: str,
+        default: Any = None,
+        type: Optional[type] = None,
+        help: Optional[str] = None,
+        metavar: Optional[str] = None,
+        multiple: bool = False,
+        file_name: Optional[str] = None,
+        group_name: Optional[str] = None,
+        callback: Optional[Callable[[Any], None]] = None,
+    ) -> None:
+        if default is None and multiple:
+            default = []
+        self.name = name
+        if type is None:
+            raise ValueError("type must not be None")
+        self.type = type
+        self.help = help
+        self.metavar = metavar
+        self.multiple = multiple
+        self.file_name = file_name
+        self.group_name = group_name
+        self.callback = callback
+        self.default = default
+        self._value = _Option.UNSET  # type: Any
+
+    def value(self) -> Any:
+        return self.default if self._value is _Option.UNSET else self._value
+
+    def parse(self, value: str) -> Any:
+        _parse = {
+            datetime.datetime: self._parse_datetime,
+            datetime.timedelta: self._parse_timedelta,
+            bool: self._parse_bool,
+            basestring_type: self._parse_string,
+        }.get(
+            self.type, self.type
+        )  # type: Callable[[str], Any]
+        if self.multiple:
+            self._value = []
+            for part in value.split(","):
+                if issubclass(self.type, numbers.Integral):
+                    # allow ranges of the form X:Y (inclusive at both ends)
+                    lo_str, _, hi_str = part.partition(":")
+                    lo = _parse(lo_str)
+                    hi = _parse(hi_str) if hi_str else lo
+                    self._value.extend(range(lo, hi + 1))
+                else:
+                    self._value.append(_parse(part))
+        else:
+            self._value = _parse(value)
+        if self.callback is not None:
+            self.callback(self._value)
+        return self.value()
+
+    def set(self, value: Any) -> None:
+        if self.multiple:
+            if not isinstance(value, list):
+                raise Error(
+                    "Option %r is required to be a list of %s"
+                    % (self.name, self.type.__name__)
+                )
+            for item in value:
+                if item is not None and not isinstance(item, self.type):
+                    raise Error(
+                        "Option %r is required to be a list of %s"
+                        % (self.name, self.type.__name__)
+                    )
+        else:
+            if value is not None and not isinstance(value, self.type):
+                raise Error(
+                    "Option %r is required to be a %s (%s given)"
+                    % (self.name, self.type.__name__, type(value))
+                )
+        self._value = value
+        if self.callback is not None:
+            self.callback(self._value)
+
+    # Supported date/time formats in our options
+    _DATETIME_FORMATS = [
+        "%a %b %d %H:%M:%S %Y",
+        "%Y-%m-%d %H:%M:%S",
+        "%Y-%m-%d %H:%M",
+        "%Y-%m-%dT%H:%M",
+        "%Y%m%d %H:%M:%S",
+        "%Y%m%d %H:%M",
+        "%Y-%m-%d",
+        "%Y%m%d",
+        "%H:%M:%S",
+        "%H:%M",
+    ]
+
+    def _parse_datetime(self, value: str) -> datetime.datetime:
+        for format in self._DATETIME_FORMATS:
+            try:
+                return datetime.datetime.strptime(value, format)
+            except ValueError:
+                pass
+        raise Error("Unrecognized date/time format: %r" % value)
+
+    _TIMEDELTA_ABBREV_DICT = {
+        "h": "hours",
+        "m": "minutes",
+        "min": "minutes",
+        "s": "seconds",
+        "sec": "seconds",
+        "ms": "milliseconds",
+        "us": "microseconds",
+        "d": "days",
+        "w": "weeks",
+    }
+
+    _FLOAT_PATTERN = r"[-+]?(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][-+]?\d+)?"
+
+    _TIMEDELTA_PATTERN = re.compile(
+        r"\s*(%s)\s*(\w*)\s*" % _FLOAT_PATTERN, re.IGNORECASE
+    )
+
+    def _parse_timedelta(self, value: str) -> datetime.timedelta:
+        try:
+            sum = datetime.timedelta()
+            start = 0
+            while start < len(value):
+                m = self._TIMEDELTA_PATTERN.match(value, start)
+                if not m:
+                    raise Exception()
+                num = float(m.group(1))
+                units = m.group(2) or "seconds"
+                units = self._TIMEDELTA_ABBREV_DICT.get(units, units)
+                # This line confuses mypy when setup.py sets python_version=3.6
+                # https://github.com/python/mypy/issues/9676
+                sum += datetime.timedelta(**{units: num})  # type: ignore
+                start = m.end()
+            return sum
+        except Exception:
+            raise
+
+    def _parse_bool(self, value: str) -> bool:
+        return value.lower() not in ("false", "0", "f")
+
+    def _parse_string(self, value: str) -> str:
+        return _unicode(value)
+
+
+options = OptionParser()
+"""Global options object.
+
+All defined options are available as attributes on this object.
+"""
+
+
+def define(
+    name: str,
+    default: Any = None,
+    type: Optional[type] = None,
+    help: Optional[str] = None,
+    metavar: Optional[str] = None,
+    multiple: bool = False,
+    group: Optional[str] = None,
+    callback: Optional[Callable[[Any], None]] = None,
+) -> None:
+    """Defines an option in the global namespace.
+
+    See `OptionParser.define`.
+    """
+    return options.define(
+        name,
+        default=default,
+        type=type,
+        help=help,
+        metavar=metavar,
+        multiple=multiple,
+        group=group,
+        callback=callback,
+    )
+
+
+def parse_command_line(
+    args: Optional[List[str]] = None, final: bool = True
+) -> List[str]:
+    """Parses global options from the command line.
+
+    See `OptionParser.parse_command_line`.
+    """
+    return options.parse_command_line(args, final=final)
+
+
+def parse_config_file(path: str, final: bool = True) -> None:
+    """Parses global options from a config file.
+
+    See `OptionParser.parse_config_file`.
+    """
+    return options.parse_config_file(path, final=final)
+
+
+def print_help(file: Optional[TextIO] = None) -> None:
+    """Prints all the command line options to stderr (or another file).
+
+    See `OptionParser.print_help`.
+    """
+    return options.print_help(file)
+
+
+def add_parse_callback(callback: Callable[[], None]) -> None:
+    """Adds a parse callback, to be invoked when option parsing is done.
+
+    See `OptionParser.add_parse_callback`
+    """
+    options.add_parse_callback(callback)
+
+
+# Default options
+define_logging_options(options)
diff --git a/venv/lib/python3.9/site-packages/tornado/platform/__init__.py b/venv/lib/python3.9/site-packages/tornado/platform/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/platform/__init__.py
diff --git a/venv/lib/python3.9/site-packages/tornado/platform/asyncio.py b/venv/lib/python3.9/site-packages/tornado/platform/asyncio.py
new file mode 100644
index 00000000..a15a74df
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/platform/asyncio.py
@@ -0,0 +1,662 @@
+"""Bridges between the `asyncio` module and Tornado IOLoop.
+
+.. versionadded:: 3.2
+
+This module integrates Tornado with the ``asyncio`` module introduced
+in Python 3.4. This makes it possible to combine the two libraries on
+the same event loop.
+
+.. deprecated:: 5.0
+
+   While the code in this module is still used, it is now enabled
+   automatically when `asyncio` is available, so applications should
+   no longer need to refer to this module directly.
+
+.. note::
+
+   Tornado is designed to use a selector-based event loop. On Windows,
+   where a proactor-based event loop has been the default since Python 3.8,
+   a selector event loop is emulated by running ``select`` on a separate thread.
+   Configuring ``asyncio`` to use a selector event loop may improve performance
+   of Tornado (but may reduce performance of other ``asyncio``-based libraries
+   in the same process).
+"""
+
+import asyncio
+import atexit
+import concurrent.futures
+import errno
+import functools
+import select
+import socket
+import sys
+import threading
+import typing
+import warnings
+from tornado.gen import convert_yielded
+from tornado.ioloop import IOLoop, _Selectable
+
+from typing import Any, TypeVar, Awaitable, Callable, Union, Optional, List, Dict
+
+if typing.TYPE_CHECKING:
+    from typing import Set, Tuple  # noqa: F401
+    from typing_extensions import Protocol
+
+    class _HasFileno(Protocol):
+        def fileno(self) -> int:
+            pass
+
+    _FileDescriptorLike = Union[int, _HasFileno]
+
+_T = TypeVar("_T")
+
+
+# Collection of selector thread event loops to shut down on exit.
+_selector_loops = set()  # type: Set[AddThreadSelectorEventLoop]
+
+
+def _atexit_callback() -> None:
+    for loop in _selector_loops:
+        with loop._select_cond:
+            loop._closing_selector = True
+            loop._select_cond.notify()
+        try:
+            loop._waker_w.send(b"a")
+        except BlockingIOError:
+            pass
+        # If we don't join our (daemon) thread here, we may get a deadlock
+        # during interpreter shutdown. I don't really understand why. This
+        # deadlock happens every time in CI (both travis and appveyor) but
+        # I've never been able to reproduce locally.
+        loop._thread.join()
+    _selector_loops.clear()
+
+
+atexit.register(_atexit_callback)
+
+
+class BaseAsyncIOLoop(IOLoop):
+    def initialize(  # type: ignore
+        self, asyncio_loop: asyncio.AbstractEventLoop, **kwargs: Any
+    ) -> None:
+        # asyncio_loop is always the real underlying IOLoop. This is used in
+        # ioloop.py to maintain the asyncio-to-ioloop mappings.
+        self.asyncio_loop = asyncio_loop
+        # selector_loop is an event loop that implements the add_reader family of
+        # methods. Usually the same as asyncio_loop but differs on platforms such
+        # as windows where the default event loop does not implement these methods.
+        self.selector_loop = asyncio_loop
+        if hasattr(asyncio, "ProactorEventLoop") and isinstance(
+            asyncio_loop, asyncio.ProactorEventLoop  # type: ignore
+        ):
+            # Ignore this line for mypy because the abstract method checker
+            # doesn't understand dynamic proxies.
+            self.selector_loop = AddThreadSelectorEventLoop(asyncio_loop)  # type: ignore
+        # Maps fd to (fileobj, handler function) pair (as in IOLoop.add_handler)
+        self.handlers = {}  # type: Dict[int, Tuple[Union[int, _Selectable], Callable]]
+        # Set of fds listening for reads/writes
+        self.readers = set()  # type: Set[int]
+        self.writers = set()  # type: Set[int]
+        self.closing = False
+        # If an asyncio loop was closed through an asyncio interface
+        # instead of IOLoop.close(), we'd never hear about it and may
+        # have left a dangling reference in our map. In case an
+        # application (or, more likely, a test suite) creates and
+        # destroys a lot of event loops in this way, check here to
+        # ensure that we don't have a lot of dead loops building up in
+        # the map.
+        #
+        # TODO(bdarnell): consider making self.asyncio_loop a weakref
+        # for AsyncIOMainLoop and make _ioloop_for_asyncio a
+        # WeakKeyDictionary.
+        for loop in IOLoop._ioloop_for_asyncio.copy():
+            if loop.is_closed():
+                try:
+                    del IOLoop._ioloop_for_asyncio[loop]
+                except KeyError:
+                    pass
+
+        # Make sure we don't already have an IOLoop for this asyncio loop
+        existing_loop = IOLoop._ioloop_for_asyncio.setdefault(asyncio_loop, self)
+        if existing_loop is not self:
+            raise RuntimeError(
+                f"IOLoop {existing_loop} already associated with asyncio loop {asyncio_loop}"
+            )
+
+        super().initialize(**kwargs)
+
+    def close(self, all_fds: bool = False) -> None:
+        self.closing = True
+        for fd in list(self.handlers):
+            fileobj, handler_func = self.handlers[fd]
+            self.remove_handler(fd)
+            if all_fds:
+                self.close_fd(fileobj)
+        # Remove the mapping before closing the asyncio loop. If this
+        # happened in the other order, we could race against another
+        # initialize() call which would see the closed asyncio loop,
+        # assume it was closed from the asyncio side, and do this
+        # cleanup for us, leading to a KeyError.
+        del IOLoop._ioloop_for_asyncio[self.asyncio_loop]
+        if self.selector_loop is not self.asyncio_loop:
+            self.selector_loop.close()
+        self.asyncio_loop.close()
+
+    def add_handler(
+        self, fd: Union[int, _Selectable], handler: Callable[..., None], events: int
+    ) -> None:
+        fd, fileobj = self.split_fd(fd)
+        if fd in self.handlers:
+            raise ValueError("fd %s added twice" % fd)
+        self.handlers[fd] = (fileobj, handler)
+        if events & IOLoop.READ:
+            self.selector_loop.add_reader(fd, self._handle_events, fd, IOLoop.READ)
+            self.readers.add(fd)
+        if events & IOLoop.WRITE:
+            self.selector_loop.add_writer(fd, self._handle_events, fd, IOLoop.WRITE)
+            self.writers.add(fd)
+
+    def update_handler(self, fd: Union[int, _Selectable], events: int) -> None:
+        fd, fileobj = self.split_fd(fd)
+        if events & IOLoop.READ:
+            if fd not in self.readers:
+                self.selector_loop.add_reader(fd, self._handle_events, fd, IOLoop.READ)
+                self.readers.add(fd)
+        else:
+            if fd in self.readers:
+                self.selector_loop.remove_reader(fd)
+                self.readers.remove(fd)
+        if events & IOLoop.WRITE:
+            if fd not in self.writers:
+                self.selector_loop.add_writer(fd, self._handle_events, fd, IOLoop.WRITE)
+                self.writers.add(fd)
+        else:
+            if fd in self.writers:
+                self.selector_loop.remove_writer(fd)
+                self.writers.remove(fd)
+
+    def remove_handler(self, fd: Union[int, _Selectable]) -> None:
+        fd, fileobj = self.split_fd(fd)
+        if fd not in self.handlers:
+            return
+        if fd in self.readers:
+            self.selector_loop.remove_reader(fd)
+            self.readers.remove(fd)
+        if fd in self.writers:
+            self.selector_loop.remove_writer(fd)
+            self.writers.remove(fd)
+        del self.handlers[fd]
+
+    def _handle_events(self, fd: int, events: int) -> None:
+        fileobj, handler_func = self.handlers[fd]
+        handler_func(fileobj, events)
+
+    def start(self) -> None:
+        self.asyncio_loop.run_forever()
+
+    def stop(self) -> None:
+        self.asyncio_loop.stop()
+
+    def call_at(
+        self, when: float, callback: Callable, *args: Any, **kwargs: Any
+    ) -> object:
+        # asyncio.call_at supports *args but not **kwargs, so bind them here.
+        # We do not synchronize self.time and asyncio_loop.time, so
+        # convert from absolute to relative.
+        return self.asyncio_loop.call_later(
+            max(0, when - self.time()),
+            self._run_callback,
+            functools.partial(callback, *args, **kwargs),
+        )
+
+    def remove_timeout(self, timeout: object) -> None:
+        timeout.cancel()  # type: ignore
+
+    def add_callback(self, callback: Callable, *args: Any, **kwargs: Any) -> None:
+        try:
+            if asyncio.get_running_loop() is self.asyncio_loop:
+                call_soon = self.asyncio_loop.call_soon
+            else:
+                call_soon = self.asyncio_loop.call_soon_threadsafe
+        except RuntimeError:
+            call_soon = self.asyncio_loop.call_soon_threadsafe
+
+        try:
+            call_soon(self._run_callback, functools.partial(callback, *args, **kwargs))
+        except RuntimeError:
+            # "Event loop is closed". Swallow the exception for
+            # consistency with PollIOLoop (and logical consistency
+            # with the fact that we can't guarantee that an
+            # add_callback that completes without error will
+            # eventually execute).
+            pass
+        except AttributeError:
+            # ProactorEventLoop may raise this instead of RuntimeError
+            # if call_soon_threadsafe races with a call to close().
+            # Swallow it too for consistency.
+            pass
+
+    def add_callback_from_signal(
+        self, callback: Callable, *args: Any, **kwargs: Any
+    ) -> None:
+        try:
+            self.asyncio_loop.call_soon_threadsafe(
+                self._run_callback, functools.partial(callback, *args, **kwargs)
+            )
+        except RuntimeError:
+            pass
+
+    def run_in_executor(
+        self,
+        executor: Optional[concurrent.futures.Executor],
+        func: Callable[..., _T],
+        *args: Any,
+    ) -> Awaitable[_T]:
+        return self.asyncio_loop.run_in_executor(executor, func, *args)
+
+    def set_default_executor(self, executor: concurrent.futures.Executor) -> None:
+        return self.asyncio_loop.set_default_executor(executor)
+
+
+class AsyncIOMainLoop(BaseAsyncIOLoop):
+    """``AsyncIOMainLoop`` creates an `.IOLoop` that corresponds to the
+    current ``asyncio`` event loop (i.e. the one returned by
+    ``asyncio.get_event_loop()``).
+
+    .. deprecated:: 5.0
+
+       Now used automatically when appropriate; it is no longer necessary
+       to refer to this class directly.
+
+    .. versionchanged:: 5.0
+
+       Closing an `AsyncIOMainLoop` now closes the underlying asyncio loop.
+    """
+
+    def initialize(self, **kwargs: Any) -> None:  # type: ignore
+        super().initialize(asyncio.get_event_loop(), **kwargs)
+
+    def _make_current(self) -> None:
+        # AsyncIOMainLoop already refers to the current asyncio loop so
+        # nothing to do here.
+        pass
+
+
+class AsyncIOLoop(BaseAsyncIOLoop):
+    """``AsyncIOLoop`` is an `.IOLoop` that runs on an ``asyncio`` event loop.
+    This class follows the usual Tornado semantics for creating new
+    ``IOLoops``; these loops are not necessarily related to the
+    ``asyncio`` default event loop.
+
+    Each ``AsyncIOLoop`` creates a new ``asyncio.EventLoop``; this object
+    can be accessed with the ``asyncio_loop`` attribute.
+
+    .. versionchanged:: 6.2
+
+       Support explicit ``asyncio_loop`` argument
+       for specifying the asyncio loop to attach to,
+       rather than always creating a new one with the default policy.
+
+    .. versionchanged:: 5.0
+
+       When an ``AsyncIOLoop`` becomes the current `.IOLoop`, it also sets
+       the current `asyncio` event loop.
+
+    .. deprecated:: 5.0
+
+       Now used automatically when appropriate; it is no longer necessary
+       to refer to this class directly.
+    """
+
+    def initialize(self, **kwargs: Any) -> None:  # type: ignore
+        self.is_current = False
+        loop = None
+        if "asyncio_loop" not in kwargs:
+            kwargs["asyncio_loop"] = loop = asyncio.new_event_loop()
+        try:
+            super().initialize(**kwargs)
+        except Exception:
+            # If initialize() does not succeed (taking ownership of the loop),
+            # we have to close it.
+            if loop is not None:
+                loop.close()
+            raise
+
+    def close(self, all_fds: bool = False) -> None:
+        if self.is_current:
+            self._clear_current()
+        super().close(all_fds=all_fds)
+
+    def _make_current(self) -> None:
+        if not self.is_current:
+            try:
+                self.old_asyncio = asyncio.get_event_loop()
+            except (RuntimeError, AssertionError):
+                self.old_asyncio = None  # type: ignore
+            self.is_current = True
+        asyncio.set_event_loop(self.asyncio_loop)
+
+    def _clear_current_hook(self) -> None:
+        if self.is_current:
+            asyncio.set_event_loop(self.old_asyncio)
+            self.is_current = False
+
+
+def to_tornado_future(asyncio_future: asyncio.Future) -> asyncio.Future:
+    """Convert an `asyncio.Future` to a `tornado.concurrent.Future`.
+
+    .. versionadded:: 4.1
+
+    .. deprecated:: 5.0
+       Tornado ``Futures`` have been merged with `asyncio.Future`,
+       so this method is now a no-op.
+    """
+    return asyncio_future
+
+
+def to_asyncio_future(tornado_future: asyncio.Future) -> asyncio.Future:
+    """Convert a Tornado yieldable object to an `asyncio.Future`.
+
+    .. versionadded:: 4.1
+
+    .. versionchanged:: 4.3
+       Now accepts any yieldable object, not just
+       `tornado.concurrent.Future`.
+
+    .. deprecated:: 5.0
+       Tornado ``Futures`` have been merged with `asyncio.Future`,
+       so this method is now equivalent to `tornado.gen.convert_yielded`.
+    """
+    return convert_yielded(tornado_future)
+
+
+if sys.platform == "win32" and hasattr(asyncio, "WindowsSelectorEventLoopPolicy"):
+    # "Any thread" and "selector" should be orthogonal, but there's not a clean
+    # interface for composing policies so pick the right base.
+    _BasePolicy = asyncio.WindowsSelectorEventLoopPolicy  # type: ignore
+else:
+    _BasePolicy = asyncio.DefaultEventLoopPolicy
+
+
+class AnyThreadEventLoopPolicy(_BasePolicy):  # type: ignore
+    """Event loop policy that allows loop creation on any thread.
+
+    The default `asyncio` event loop policy only automatically creates
+    event loops in the main threads. Other threads must create event
+    loops explicitly or `asyncio.get_event_loop` (and therefore
+    `.IOLoop.current`) will fail. Installing this policy allows event
+    loops to be created automatically on any thread, matching the
+    behavior of Tornado versions prior to 5.0 (or 5.0 on Python 2).
+
+    Usage::
+
+        asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
+
+    .. versionadded:: 5.0
+
+    .. deprecated:: 6.2
+
+        ``AnyThreadEventLoopPolicy`` affects the implicit creation
+        of an event loop, which is deprecated in Python 3.10 and
+        will be removed in a future version of Python. At that time
+        ``AnyThreadEventLoopPolicy`` will no longer be useful.
+        If you are relying on it, use `asyncio.new_event_loop`
+        or `asyncio.run` explicitly in any non-main threads that
+        need event loops.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+        warnings.warn(
+            "AnyThreadEventLoopPolicy is deprecated, use asyncio.run "
+            "or asyncio.new_event_loop instead",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+
+    def get_event_loop(self) -> asyncio.AbstractEventLoop:
+        try:
+            return super().get_event_loop()
+        except (RuntimeError, AssertionError):
+            # This was an AssertionError in Python 3.4.2 (which ships with Debian Jessie)
+            # and changed to a RuntimeError in 3.4.3.
+            # "There is no current event loop in thread %r"
+            loop = self.new_event_loop()
+            self.set_event_loop(loop)
+            return loop
+
+
+class AddThreadSelectorEventLoop(asyncio.AbstractEventLoop):
+    """Wrap an event loop to add implementations of the ``add_reader`` method family.
+
+    Instances of this class start a second thread to run a selector.
+    This thread is completely hidden from the user; all callbacks are
+    run on the wrapped event loop's thread.
+
+    This class is used automatically by Tornado; applications should not need
+    to refer to it directly.
+
+    It is safe to wrap any event loop with this class, although it only makes sense
+    for event loops that do not implement the ``add_reader`` family of methods
+    themselves (i.e. ``WindowsProactorEventLoop``)
+
+    Closing the ``AddThreadSelectorEventLoop`` also closes the wrapped event loop.
+
+    """
+
+    # This class is a __getattribute__-based proxy. All attributes other than those
+    # in this set are proxied through to the underlying loop.
+    MY_ATTRIBUTES = {
+        "_consume_waker",
+        "_select_cond",
+        "_select_args",
+        "_closing_selector",
+        "_thread",
+        "_handle_event",
+        "_readers",
+        "_real_loop",
+        "_start_select",
+        "_run_select",
+        "_handle_select",
+        "_wake_selector",
+        "_waker_r",
+        "_waker_w",
+        "_writers",
+        "add_reader",
+        "add_writer",
+        "close",
+        "remove_reader",
+        "remove_writer",
+    }
+
+    def __getattribute__(self, name: str) -> Any:
+        if name in AddThreadSelectorEventLoop.MY_ATTRIBUTES:
+            return super().__getattribute__(name)
+        return getattr(self._real_loop, name)
+
+    def __init__(self, real_loop: asyncio.AbstractEventLoop) -> None:
+        self._real_loop = real_loop
+
+        # Create a thread to run the select system call. We manage this thread
+        # manually so we can trigger a clean shutdown from an atexit hook. Note
+        # that due to the order of operations at shutdown, only daemon threads
+        # can be shut down in this way (non-daemon threads would require the
+        # introduction of a new hook: https://bugs.python.org/issue41962)
+        self._select_cond = threading.Condition()
+        self._select_args = (
+            None
+        )  # type: Optional[Tuple[List[_FileDescriptorLike], List[_FileDescriptorLike]]]
+        self._closing_selector = False
+        self._thread = threading.Thread(
+            name="Tornado selector",
+            daemon=True,
+            target=self._run_select,
+        )
+        self._thread.start()
+        # Start the select loop once the loop is started.
+        self._real_loop.call_soon(self._start_select)
+
+        self._readers = {}  # type: Dict[_FileDescriptorLike, Callable]
+        self._writers = {}  # type: Dict[_FileDescriptorLike, Callable]
+
+        # Writing to _waker_w will wake up the selector thread, which
+        # watches for _waker_r to be readable.
+        self._waker_r, self._waker_w = socket.socketpair()
+        self._waker_r.setblocking(False)
+        self._waker_w.setblocking(False)
+        _selector_loops.add(self)
+        self.add_reader(self._waker_r, self._consume_waker)
+
+    def __del__(self) -> None:
+        # If the top-level application code uses asyncio interfaces to
+        # start and stop the event loop, no objects created in Tornado
+        # can get a clean shutdown notification. If we're just left to
+        # be GC'd, we must explicitly close our sockets to avoid
+        # logging warnings.
+        _selector_loops.discard(self)
+        self._waker_r.close()
+        self._waker_w.close()
+
+    def close(self) -> None:
+        with self._select_cond:
+            self._closing_selector = True
+            self._select_cond.notify()
+        self._wake_selector()
+        self._thread.join()
+        _selector_loops.discard(self)
+        self._waker_r.close()
+        self._waker_w.close()
+        self._real_loop.close()
+
+    def _wake_selector(self) -> None:
+        try:
+            self._waker_w.send(b"a")
+        except BlockingIOError:
+            pass
+
+    def _consume_waker(self) -> None:
+        try:
+            self._waker_r.recv(1024)
+        except BlockingIOError:
+            pass
+
+    def _start_select(self) -> None:
+        # Capture reader and writer sets here in the event loop
+        # thread to avoid any problems with concurrent
+        # modification while the select loop uses them.
+        with self._select_cond:
+            assert self._select_args is None
+            self._select_args = (list(self._readers.keys()), list(self._writers.keys()))
+            self._select_cond.notify()
+
+    def _run_select(self) -> None:
+        while True:
+            with self._select_cond:
+                while self._select_args is None and not self._closing_selector:
+                    self._select_cond.wait()
+                if self._closing_selector:
+                    return
+                assert self._select_args is not None
+                to_read, to_write = self._select_args
+                self._select_args = None
+
+            # We use the simpler interface of the select module instead of
+            # the more stateful interface in the selectors module because
+            # this class is only intended for use on windows, where
+            # select.select is the only option. The selector interface
+            # does not have well-documented thread-safety semantics that
+            # we can rely on so ensuring proper synchronization would be
+            # tricky.
+            try:
+                # On windows, selecting on a socket for write will not
+                # return the socket when there is an error (but selecting
+                # for reads works). Also select for errors when selecting
+                # for writes, and merge the results.
+                #
+                # This pattern is also used in
+                # https://github.com/python/cpython/blob/v3.8.0/Lib/selectors.py#L312-L317
+                rs, ws, xs = select.select(to_read, to_write, to_write)
+                ws = ws + xs
+            except OSError as e:
+                # After remove_reader or remove_writer is called, the file
+                # descriptor may subsequently be closed on the event loop
+                # thread. It's possible that this select thread hasn't
+                # gotten into the select system call by the time that
+                # happens in which case (at least on macOS), select may
+                # raise a "bad file descriptor" error. If we get that
+                # error, check and see if we're also being woken up by
+                # polling the waker alone. If we are, just return to the
+                # event loop and we'll get the updated set of file
+                # descriptors on the next iteration. Otherwise, raise the
+                # original error.
+                if e.errno == getattr(errno, "WSAENOTSOCK", errno.EBADF):
+                    rs, _, _ = select.select([self._waker_r.fileno()], [], [], 0)
+                    if rs:
+                        ws = []
+                    else:
+                        raise
+                else:
+                    raise
+
+            try:
+                self._real_loop.call_soon_threadsafe(self._handle_select, rs, ws)
+            except RuntimeError:
+                # "Event loop is closed". Swallow the exception for
+                # consistency with PollIOLoop (and logical consistency
+                # with the fact that we can't guarantee that an
+                # add_callback that completes without error will
+                # eventually execute).
+                pass
+            except AttributeError:
+                # ProactorEventLoop may raise this instead of RuntimeError
+                # if call_soon_threadsafe races with a call to close().
+                # Swallow it too for consistency.
+                pass
+
+    def _handle_select(
+        self, rs: List["_FileDescriptorLike"], ws: List["_FileDescriptorLike"]
+    ) -> None:
+        for r in rs:
+            self._handle_event(r, self._readers)
+        for w in ws:
+            self._handle_event(w, self._writers)
+        self._start_select()
+
+    def _handle_event(
+        self,
+        fd: "_FileDescriptorLike",
+        cb_map: Dict["_FileDescriptorLike", Callable],
+    ) -> None:
+        try:
+            callback = cb_map[fd]
+        except KeyError:
+            return
+        callback()
+
+    def add_reader(
+        self, fd: "_FileDescriptorLike", callback: Callable[..., None], *args: Any
+    ) -> None:
+        self._readers[fd] = functools.partial(callback, *args)
+        self._wake_selector()
+
+    def add_writer(
+        self, fd: "_FileDescriptorLike", callback: Callable[..., None], *args: Any
+    ) -> None:
+        self._writers[fd] = functools.partial(callback, *args)
+        self._wake_selector()
+
+    def remove_reader(self, fd: "_FileDescriptorLike") -> bool:
+        try:
+            del self._readers[fd]
+        except KeyError:
+            return False
+        self._wake_selector()
+        return True
+
+    def remove_writer(self, fd: "_FileDescriptorLike") -> bool:
+        try:
+            del self._writers[fd]
+        except KeyError:
+            return False
+        self._wake_selector()
+        return True
diff --git a/venv/lib/python3.9/site-packages/tornado/platform/caresresolver.py b/venv/lib/python3.9/site-packages/tornado/platform/caresresolver.py
new file mode 100644
index 00000000..1ba45c9a
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/platform/caresresolver.py
@@ -0,0 +1,94 @@
+import pycares  # type: ignore
+import socket
+
+from tornado.concurrent import Future
+from tornado import gen
+from tornado.ioloop import IOLoop
+from tornado.netutil import Resolver, is_valid_ip
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Generator, Any, List, Tuple, Dict  # noqa: F401
+
+
+class CaresResolver(Resolver):
+    """Name resolver based on the c-ares library.
+
+    This is a non-blocking and non-threaded resolver.  It may not produce the
+    same results as the system resolver, but can be used for non-blocking
+    resolution when threads cannot be used.
+
+    ``pycares`` will not return a mix of ``AF_INET`` and ``AF_INET6`` when
+    ``family`` is ``AF_UNSPEC``, so it is only recommended for use in
+    ``AF_INET`` (i.e. IPv4).  This is the default for
+    ``tornado.simple_httpclient``, but other libraries may default to
+    ``AF_UNSPEC``.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. deprecated:: 6.2
+       This class is deprecated and will be removed in Tornado 7.0. Use the default
+       thread-based resolver instead.
+    """
+
+    def initialize(self) -> None:
+        self.io_loop = IOLoop.current()
+        self.channel = pycares.Channel(sock_state_cb=self._sock_state_cb)
+        self.fds = {}  # type: Dict[int, int]
+
+    def _sock_state_cb(self, fd: int, readable: bool, writable: bool) -> None:
+        state = (IOLoop.READ if readable else 0) | (IOLoop.WRITE if writable else 0)
+        if not state:
+            self.io_loop.remove_handler(fd)
+            del self.fds[fd]
+        elif fd in self.fds:
+            self.io_loop.update_handler(fd, state)
+            self.fds[fd] = state
+        else:
+            self.io_loop.add_handler(fd, self._handle_events, state)
+            self.fds[fd] = state
+
+    def _handle_events(self, fd: int, events: int) -> None:
+        read_fd = pycares.ARES_SOCKET_BAD
+        write_fd = pycares.ARES_SOCKET_BAD
+        if events & IOLoop.READ:
+            read_fd = fd
+        if events & IOLoop.WRITE:
+            write_fd = fd
+        self.channel.process_fd(read_fd, write_fd)
+
+    @gen.coroutine
+    def resolve(
+        self, host: str, port: int, family: int = 0
+    ) -> "Generator[Any, Any, List[Tuple[int, Any]]]":
+        if is_valid_ip(host):
+            addresses = [host]
+        else:
+            # gethostbyname doesn't take callback as a kwarg
+            fut = Future()  # type: Future[Tuple[Any, Any]]
+            self.channel.gethostbyname(
+                host, family, lambda result, error: fut.set_result((result, error))
+            )
+            result, error = yield fut
+            if error:
+                raise IOError(
+                    "C-Ares returned error %s: %s while resolving %s"
+                    % (error, pycares.errno.strerror(error), host)
+                )
+            addresses = result.addresses
+        addrinfo = []
+        for address in addresses:
+            if "." in address:
+                address_family = socket.AF_INET
+            elif ":" in address:
+                address_family = socket.AF_INET6
+            else:
+                address_family = socket.AF_UNSPEC
+            if family != socket.AF_UNSPEC and family != address_family:
+                raise IOError(
+                    "Requested socket family %d but got %d" % (family, address_family)
+                )
+            addrinfo.append((typing.cast(int, address_family), (address, port)))
+        return addrinfo
diff --git a/venv/lib/python3.9/site-packages/tornado/platform/twisted.py b/venv/lib/python3.9/site-packages/tornado/platform/twisted.py
new file mode 100644
index 00000000..153fe436
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/platform/twisted.py
@@ -0,0 +1,150 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+"""Bridges between the Twisted package and Tornado.
+"""
+
+import socket
+import sys
+
+import twisted.internet.abstract  # type: ignore
+import twisted.internet.asyncioreactor  # type: ignore
+from twisted.internet.defer import Deferred  # type: ignore
+from twisted.python import failure  # type: ignore
+import twisted.names.cache  # type: ignore
+import twisted.names.client  # type: ignore
+import twisted.names.hosts  # type: ignore
+import twisted.names.resolve  # type: ignore
+
+
+from tornado.concurrent import Future, future_set_exc_info
+from tornado.escape import utf8
+from tornado import gen
+from tornado.netutil import Resolver
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Generator, Any, List, Tuple  # noqa: F401
+
+
+class TwistedResolver(Resolver):
+    """Twisted-based asynchronous resolver.
+
+    This is a non-blocking and non-threaded resolver.  It is
+    recommended only when threads cannot be used, since it has
+    limitations compared to the standard ``getaddrinfo``-based
+    `~tornado.netutil.Resolver` and
+    `~tornado.netutil.DefaultExecutorResolver`.  Specifically, it returns at
+    most one result, and arguments other than ``host`` and ``family``
+    are ignored.  It may fail to resolve when ``family`` is not
+    ``socket.AF_UNSPEC``.
+
+    Requires Twisted 12.1 or newer.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. deprecated:: 6.2
+       This class is deprecated and will be removed in Tornado 7.0. Use the default
+       thread-based resolver instead.
+    """
+
+    def initialize(self) -> None:
+        # partial copy of twisted.names.client.createResolver, which doesn't
+        # allow for a reactor to be passed in.
+        self.reactor = twisted.internet.asyncioreactor.AsyncioSelectorReactor()
+
+        host_resolver = twisted.names.hosts.Resolver("/etc/hosts")
+        cache_resolver = twisted.names.cache.CacheResolver(reactor=self.reactor)
+        real_resolver = twisted.names.client.Resolver(
+            "/etc/resolv.conf", reactor=self.reactor
+        )
+        self.resolver = twisted.names.resolve.ResolverChain(
+            [host_resolver, cache_resolver, real_resolver]
+        )
+
+    @gen.coroutine
+    def resolve(
+        self, host: str, port: int, family: int = 0
+    ) -> "Generator[Any, Any, List[Tuple[int, Any]]]":
+        # getHostByName doesn't accept IP addresses, so if the input
+        # looks like an IP address just return it immediately.
+        if twisted.internet.abstract.isIPAddress(host):
+            resolved = host
+            resolved_family = socket.AF_INET
+        elif twisted.internet.abstract.isIPv6Address(host):
+            resolved = host
+            resolved_family = socket.AF_INET6
+        else:
+            deferred = self.resolver.getHostByName(utf8(host))
+            fut = Future()  # type: Future[Any]
+            deferred.addBoth(fut.set_result)
+            resolved = yield fut
+            if isinstance(resolved, failure.Failure):
+                try:
+                    resolved.raiseException()
+                except twisted.names.error.DomainError as e:
+                    raise IOError(e)
+            elif twisted.internet.abstract.isIPAddress(resolved):
+                resolved_family = socket.AF_INET
+            elif twisted.internet.abstract.isIPv6Address(resolved):
+                resolved_family = socket.AF_INET6
+            else:
+                resolved_family = socket.AF_UNSPEC
+        if family != socket.AF_UNSPEC and family != resolved_family:
+            raise Exception(
+                "Requested socket family %d but got %d" % (family, resolved_family)
+            )
+        result = [(typing.cast(int, resolved_family), (resolved, port))]
+        return result
+
+
+def install() -> None:
+    """Install ``AsyncioSelectorReactor`` as the default Twisted reactor.
+
+    .. deprecated:: 5.1
+
+       This function is provided for backwards compatibility; code
+       that does not require compatibility with older versions of
+       Tornado should use
+       ``twisted.internet.asyncioreactor.install()`` directly.
+
+    .. versionchanged:: 6.0.3
+
+       In Tornado 5.x and before, this function installed a reactor
+       based on the Tornado ``IOLoop``. When that reactor
+       implementation was removed in Tornado 6.0.0, this function was
+       removed as well. It was restored in Tornado 6.0.3 using the
+       ``asyncio`` reactor instead.
+
+    """
+    from twisted.internet.asyncioreactor import install
+
+    install()
+
+
+if hasattr(gen.convert_yielded, "register"):
+
+    @gen.convert_yielded.register(Deferred)  # type: ignore
+    def _(d: Deferred) -> Future:
+        f = Future()  # type: Future[Any]
+
+        def errback(failure: failure.Failure) -> None:
+            try:
+                failure.raiseException()
+                # Should never happen, but just in case
+                raise Exception("errback called without error")
+            except:
+                future_set_exc_info(f, sys.exc_info())
+
+        d.addCallbacks(f.set_result, errback)
+        return f
diff --git a/venv/lib/python3.9/site-packages/tornado/process.py b/venv/lib/python3.9/site-packages/tornado/process.py
new file mode 100644
index 00000000..26428feb
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/process.py
@@ -0,0 +1,373 @@
+#
+# Copyright 2011 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Utilities for working with multiple processes, including both forking
+the server into multiple processes and managing subprocesses.
+"""
+
+import os
+import multiprocessing
+import signal
+import subprocess
+import sys
+import time
+
+from binascii import hexlify
+
+from tornado.concurrent import (
+    Future,
+    future_set_result_unless_cancelled,
+    future_set_exception_unless_cancelled,
+)
+from tornado import ioloop
+from tornado.iostream import PipeIOStream
+from tornado.log import gen_log
+
+import typing
+from typing import Optional, Any, Callable
+
+if typing.TYPE_CHECKING:
+    from typing import List  # noqa: F401
+
+# Re-export this exception for convenience.
+CalledProcessError = subprocess.CalledProcessError
+
+
+def cpu_count() -> int:
+    """Returns the number of processors on this machine."""
+    if multiprocessing is None:
+        return 1
+    try:
+        return multiprocessing.cpu_count()
+    except NotImplementedError:
+        pass
+    try:
+        return os.sysconf("SC_NPROCESSORS_CONF")  # type: ignore
+    except (AttributeError, ValueError):
+        pass
+    gen_log.error("Could not detect number of processors; assuming 1")
+    return 1
+
+
+def _reseed_random() -> None:
+    if "random" not in sys.modules:
+        return
+    import random
+
+    # If os.urandom is available, this method does the same thing as
+    # random.seed (at least as of python 2.6).  If os.urandom is not
+    # available, we mix in the pid in addition to a timestamp.
+    try:
+        seed = int(hexlify(os.urandom(16)), 16)
+    except NotImplementedError:
+        seed = int(time.time() * 1000) ^ os.getpid()
+    random.seed(seed)
+
+
+_task_id = None
+
+
+def fork_processes(
+    num_processes: Optional[int], max_restarts: Optional[int] = None
+) -> int:
+    """Starts multiple worker processes.
+
+    If ``num_processes`` is None or <= 0, we detect the number of cores
+    available on this machine and fork that number of child
+    processes. If ``num_processes`` is given and > 0, we fork that
+    specific number of sub-processes.
+
+    Since we use processes and not threads, there is no shared memory
+    between any server code.
+
+    Note that multiple processes are not compatible with the autoreload
+    module (or the ``autoreload=True`` option to `tornado.web.Application`
+    which defaults to True when ``debug=True``).
+    When using multiple processes, no IOLoops can be created or
+    referenced until after the call to ``fork_processes``.
+
+    In each child process, ``fork_processes`` returns its *task id*, a
+    number between 0 and ``num_processes``.  Processes that exit
+    abnormally (due to a signal or non-zero exit status) are restarted
+    with the same id (up to ``max_restarts`` times).  In the parent
+    process, ``fork_processes`` calls ``sys.exit(0)`` after all child
+    processes have exited normally.
+
+    max_restarts defaults to 100.
+
+    Availability: Unix
+    """
+    if sys.platform == "win32":
+        # The exact form of this condition matters to mypy; it understands
+        # if but not assert in this context.
+        raise Exception("fork not available on windows")
+    if max_restarts is None:
+        max_restarts = 100
+
+    global _task_id
+    assert _task_id is None
+    if num_processes is None or num_processes <= 0:
+        num_processes = cpu_count()
+    gen_log.info("Starting %d processes", num_processes)
+    children = {}
+
+    def start_child(i: int) -> Optional[int]:
+        pid = os.fork()
+        if pid == 0:
+            # child process
+            _reseed_random()
+            global _task_id
+            _task_id = i
+            return i
+        else:
+            children[pid] = i
+            return None
+
+    for i in range(num_processes):
+        id = start_child(i)
+        if id is not None:
+            return id
+    num_restarts = 0
+    while children:
+        pid, status = os.wait()
+        if pid not in children:
+            continue
+        id = children.pop(pid)
+        if os.WIFSIGNALED(status):
+            gen_log.warning(
+                "child %d (pid %d) killed by signal %d, restarting",
+                id,
+                pid,
+                os.WTERMSIG(status),
+            )
+        elif os.WEXITSTATUS(status) != 0:
+            gen_log.warning(
+                "child %d (pid %d) exited with status %d, restarting",
+                id,
+                pid,
+                os.WEXITSTATUS(status),
+            )
+        else:
+            gen_log.info("child %d (pid %d) exited normally", id, pid)
+            continue
+        num_restarts += 1
+        if num_restarts > max_restarts:
+            raise RuntimeError("Too many child restarts, giving up")
+        new_id = start_child(id)
+        if new_id is not None:
+            return new_id
+    # All child processes exited cleanly, so exit the master process
+    # instead of just returning to right after the call to
+    # fork_processes (which will probably just start up another IOLoop
+    # unless the caller checks the return value).
+    sys.exit(0)
+
+
+def task_id() -> Optional[int]:
+    """Returns the current task id, if any.
+
+    Returns None if this process was not created by `fork_processes`.
+    """
+    global _task_id
+    return _task_id
+
+
+class Subprocess(object):
+    """Wraps ``subprocess.Popen`` with IOStream support.
+
+    The constructor is the same as ``subprocess.Popen`` with the following
+    additions:
+
+    * ``stdin``, ``stdout``, and ``stderr`` may have the value
+      ``tornado.process.Subprocess.STREAM``, which will make the corresponding
+      attribute of the resulting Subprocess a `.PipeIOStream`. If this option
+      is used, the caller is responsible for closing the streams when done
+      with them.
+
+    The ``Subprocess.STREAM`` option and the ``set_exit_callback`` and
+    ``wait_for_exit`` methods do not work on Windows. There is
+    therefore no reason to use this class instead of
+    ``subprocess.Popen`` on that platform.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    """
+
+    STREAM = object()
+
+    _initialized = False
+    _waiting = {}  # type: ignore
+    _old_sigchld = None
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        self.io_loop = ioloop.IOLoop.current()
+        # All FDs we create should be closed on error; those in to_close
+        # should be closed in the parent process on success.
+        pipe_fds = []  # type: List[int]
+        to_close = []  # type: List[int]
+        if kwargs.get("stdin") is Subprocess.STREAM:
+            in_r, in_w = os.pipe()
+            kwargs["stdin"] = in_r
+            pipe_fds.extend((in_r, in_w))
+            to_close.append(in_r)
+            self.stdin = PipeIOStream(in_w)
+        if kwargs.get("stdout") is Subprocess.STREAM:
+            out_r, out_w = os.pipe()
+            kwargs["stdout"] = out_w
+            pipe_fds.extend((out_r, out_w))
+            to_close.append(out_w)
+            self.stdout = PipeIOStream(out_r)
+        if kwargs.get("stderr") is Subprocess.STREAM:
+            err_r, err_w = os.pipe()
+            kwargs["stderr"] = err_w
+            pipe_fds.extend((err_r, err_w))
+            to_close.append(err_w)
+            self.stderr = PipeIOStream(err_r)
+        try:
+            self.proc = subprocess.Popen(*args, **kwargs)
+        except:
+            for fd in pipe_fds:
+                os.close(fd)
+            raise
+        for fd in to_close:
+            os.close(fd)
+        self.pid = self.proc.pid
+        for attr in ["stdin", "stdout", "stderr"]:
+            if not hasattr(self, attr):  # don't clobber streams set above
+                setattr(self, attr, getattr(self.proc, attr))
+        self._exit_callback = None  # type: Optional[Callable[[int], None]]
+        self.returncode = None  # type: Optional[int]
+
+    def set_exit_callback(self, callback: Callable[[int], None]) -> None:
+        """Runs ``callback`` when this process exits.
+
+        The callback takes one argument, the return code of the process.
+
+        This method uses a ``SIGCHLD`` handler, which is a global setting
+        and may conflict if you have other libraries trying to handle the
+        same signal.  If you are using more than one ``IOLoop`` it may
+        be necessary to call `Subprocess.initialize` first to designate
+        one ``IOLoop`` to run the signal handlers.
+
+        In many cases a close callback on the stdout or stderr streams
+        can be used as an alternative to an exit callback if the
+        signal handler is causing a problem.
+
+        Availability: Unix
+        """
+        self._exit_callback = callback
+        Subprocess.initialize()
+        Subprocess._waiting[self.pid] = self
+        Subprocess._try_cleanup_process(self.pid)
+
+    def wait_for_exit(self, raise_error: bool = True) -> "Future[int]":
+        """Returns a `.Future` which resolves when the process exits.
+
+        Usage::
+
+            ret = yield proc.wait_for_exit()
+
+        This is a coroutine-friendly alternative to `set_exit_callback`
+        (and a replacement for the blocking `subprocess.Popen.wait`).
+
+        By default, raises `subprocess.CalledProcessError` if the process
+        has a non-zero exit status. Use ``wait_for_exit(raise_error=False)``
+        to suppress this behavior and return the exit status without raising.
+
+        .. versionadded:: 4.2
+
+        Availability: Unix
+        """
+        future = Future()  # type: Future[int]
+
+        def callback(ret: int) -> None:
+            if ret != 0 and raise_error:
+                # Unfortunately we don't have the original args any more.
+                future_set_exception_unless_cancelled(
+                    future, CalledProcessError(ret, "unknown")
+                )
+            else:
+                future_set_result_unless_cancelled(future, ret)
+
+        self.set_exit_callback(callback)
+        return future
+
+    @classmethod
+    def initialize(cls) -> None:
+        """Initializes the ``SIGCHLD`` handler.
+
+        The signal handler is run on an `.IOLoop` to avoid locking issues.
+        Note that the `.IOLoop` used for signal handling need not be the
+        same one used by individual Subprocess objects (as long as the
+        ``IOLoops`` are each running in separate threads).
+
+        .. versionchanged:: 5.0
+           The ``io_loop`` argument (deprecated since version 4.1) has been
+           removed.
+
+        Availability: Unix
+        """
+        if cls._initialized:
+            return
+        io_loop = ioloop.IOLoop.current()
+        cls._old_sigchld = signal.signal(
+            signal.SIGCHLD,
+            lambda sig, frame: io_loop.add_callback_from_signal(cls._cleanup),
+        )
+        cls._initialized = True
+
+    @classmethod
+    def uninitialize(cls) -> None:
+        """Removes the ``SIGCHLD`` handler."""
+        if not cls._initialized:
+            return
+        signal.signal(signal.SIGCHLD, cls._old_sigchld)
+        cls._initialized = False
+
+    @classmethod
+    def _cleanup(cls) -> None:
+        for pid in list(cls._waiting.keys()):  # make a copy
+            cls._try_cleanup_process(pid)
+
+    @classmethod
+    def _try_cleanup_process(cls, pid: int) -> None:
+        try:
+            ret_pid, status = os.waitpid(pid, os.WNOHANG)  # type: ignore
+        except ChildProcessError:
+            return
+        if ret_pid == 0:
+            return
+        assert ret_pid == pid
+        subproc = cls._waiting.pop(pid)
+        subproc.io_loop.add_callback_from_signal(subproc._set_returncode, status)
+
+    def _set_returncode(self, status: int) -> None:
+        if sys.platform == "win32":
+            self.returncode = -1
+        else:
+            if os.WIFSIGNALED(status):
+                self.returncode = -os.WTERMSIG(status)
+            else:
+                assert os.WIFEXITED(status)
+                self.returncode = os.WEXITSTATUS(status)
+        # We've taken over wait() duty from the subprocess.Popen
+        # object. If we don't inform it of the process's return code,
+        # it will log a warning at destruction in python 3.6+.
+        self.proc.returncode = self.returncode
+        if self._exit_callback:
+            callback = self._exit_callback
+            self._exit_callback = None
+            callback(self.returncode)
diff --git a/venv/lib/python3.9/site-packages/tornado/py.typed b/venv/lib/python3.9/site-packages/tornado/py.typed
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/py.typed
diff --git a/venv/lib/python3.9/site-packages/tornado/queues.py b/venv/lib/python3.9/site-packages/tornado/queues.py
new file mode 100644
index 00000000..1358d0ec
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/queues.py
@@ -0,0 +1,422 @@
+# Copyright 2015 The Tornado Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Asynchronous queues for coroutines. These classes are very similar
+to those provided in the standard library's `asyncio package
+<https://docs.python.org/3/library/asyncio-queue.html>`_.
+
+.. warning::
+
+   Unlike the standard library's `queue` module, the classes defined here
+   are *not* thread-safe. To use these queues from another thread,
+   use `.IOLoop.add_callback` to transfer control to the `.IOLoop` thread
+   before calling any queue methods.
+
+"""
+
+import collections
+import datetime
+import heapq
+
+from tornado import gen, ioloop
+from tornado.concurrent import Future, future_set_result_unless_cancelled
+from tornado.locks import Event
+
+from typing import Union, TypeVar, Generic, Awaitable, Optional
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Deque, Tuple, Any  # noqa: F401
+
+_T = TypeVar("_T")
+
+__all__ = ["Queue", "PriorityQueue", "LifoQueue", "QueueFull", "QueueEmpty"]
+
+
+class QueueEmpty(Exception):
+    """Raised by `.Queue.get_nowait` when the queue has no items."""
+
+    pass
+
+
+class QueueFull(Exception):
+    """Raised by `.Queue.put_nowait` when a queue is at its maximum size."""
+
+    pass
+
+
+def _set_timeout(
+    future: Future, timeout: Union[None, float, datetime.timedelta]
+) -> None:
+    if timeout:
+
+        def on_timeout() -> None:
+            if not future.done():
+                future.set_exception(gen.TimeoutError())
+
+        io_loop = ioloop.IOLoop.current()
+        timeout_handle = io_loop.add_timeout(timeout, on_timeout)
+        future.add_done_callback(lambda _: io_loop.remove_timeout(timeout_handle))
+
+
+class _QueueIterator(Generic[_T]):
+    def __init__(self, q: "Queue[_T]") -> None:
+        self.q = q
+
+    def __anext__(self) -> Awaitable[_T]:
+        return self.q.get()
+
+
+class Queue(Generic[_T]):
+    """Coordinate producer and consumer coroutines.
+
+    If maxsize is 0 (the default) the queue size is unbounded.
+
+    .. testcode::
+
+        import asyncio
+        from tornado.ioloop import IOLoop
+        from tornado.queues import Queue
+
+        q = Queue(maxsize=2)
+
+        async def consumer():
+            async for item in q:
+                try:
+                    print('Doing work on %s' % item)
+                    await asyncio.sleep(0.01)
+                finally:
+                    q.task_done()
+
+        async def producer():
+            for item in range(5):
+                await q.put(item)
+                print('Put %s' % item)
+
+        async def main():
+            # Start consumer without waiting (since it never finishes).
+            IOLoop.current().spawn_callback(consumer)
+            await producer()     # Wait for producer to put all tasks.
+            await q.join()       # Wait for consumer to finish all tasks.
+            print('Done')
+
+        asyncio.run(main())
+
+    .. testoutput::
+
+        Put 0
+        Put 1
+        Doing work on 0
+        Put 2
+        Doing work on 1
+        Put 3
+        Doing work on 2
+        Put 4
+        Doing work on 3
+        Doing work on 4
+        Done
+
+
+    In versions of Python without native coroutines (before 3.5),
+    ``consumer()`` could be written as::
+
+        @gen.coroutine
+        def consumer():
+            while True:
+                item = yield q.get()
+                try:
+                    print('Doing work on %s' % item)
+                    yield gen.sleep(0.01)
+                finally:
+                    q.task_done()
+
+    .. versionchanged:: 4.3
+       Added ``async for`` support in Python 3.5.
+
+    """
+
+    # Exact type depends on subclass. Could be another generic
+    # parameter and use protocols to be more precise here.
+    _queue = None  # type: Any
+
+    def __init__(self, maxsize: int = 0) -> None:
+        if maxsize is None:
+            raise TypeError("maxsize can't be None")
+
+        if maxsize < 0:
+            raise ValueError("maxsize can't be negative")
+
+        self._maxsize = maxsize
+        self._init()
+        self._getters = collections.deque([])  # type: Deque[Future[_T]]
+        self._putters = collections.deque([])  # type: Deque[Tuple[_T, Future[None]]]
+        self._unfinished_tasks = 0
+        self._finished = Event()
+        self._finished.set()
+
+    @property
+    def maxsize(self) -> int:
+        """Number of items allowed in the queue."""
+        return self._maxsize
+
+    def qsize(self) -> int:
+        """Number of items in the queue."""
+        return len(self._queue)
+
+    def empty(self) -> bool:
+        return not self._queue
+
+    def full(self) -> bool:
+        if self.maxsize == 0:
+            return False
+        else:
+            return self.qsize() >= self.maxsize
+
+    def put(
+        self, item: _T, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> "Future[None]":
+        """Put an item into the queue, perhaps waiting until there is room.
+
+        Returns a Future, which raises `tornado.util.TimeoutError` after a
+        timeout.
+
+        ``timeout`` may be a number denoting a time (on the same
+        scale as `tornado.ioloop.IOLoop.time`, normally `time.time`), or a
+        `datetime.timedelta` object for a deadline relative to the
+        current time.
+        """
+        future = Future()  # type: Future[None]
+        try:
+            self.put_nowait(item)
+        except QueueFull:
+            self._putters.append((item, future))
+            _set_timeout(future, timeout)
+        else:
+            future.set_result(None)
+        return future
+
+    def put_nowait(self, item: _T) -> None:
+        """Put an item into the queue without blocking.
+
+        If no free slot is immediately available, raise `QueueFull`.
+        """
+        self._consume_expired()
+        if self._getters:
+            assert self.empty(), "queue non-empty, why are getters waiting?"
+            getter = self._getters.popleft()
+            self.__put_internal(item)
+            future_set_result_unless_cancelled(getter, self._get())
+        elif self.full():
+            raise QueueFull
+        else:
+            self.__put_internal(item)
+
+    def get(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[_T]:
+        """Remove and return an item from the queue.
+
+        Returns an awaitable which resolves once an item is available, or raises
+        `tornado.util.TimeoutError` after a timeout.
+
+        ``timeout`` may be a number denoting a time (on the same
+        scale as `tornado.ioloop.IOLoop.time`, normally `time.time`), or a
+        `datetime.timedelta` object for a deadline relative to the
+        current time.
+
+        .. note::
+
+           The ``timeout`` argument of this method differs from that
+           of the standard library's `queue.Queue.get`. That method
+           interprets numeric values as relative timeouts; this one
+           interprets them as absolute deadlines and requires
+           ``timedelta`` objects for relative timeouts (consistent
+           with other timeouts in Tornado).
+
+        """
+        future = Future()  # type: Future[_T]
+        try:
+            future.set_result(self.get_nowait())
+        except QueueEmpty:
+            self._getters.append(future)
+            _set_timeout(future, timeout)
+        return future
+
+    def get_nowait(self) -> _T:
+        """Remove and return an item from the queue without blocking.
+
+        Return an item if one is immediately available, else raise
+        `QueueEmpty`.
+        """
+        self._consume_expired()
+        if self._putters:
+            assert self.full(), "queue not full, why are putters waiting?"
+            item, putter = self._putters.popleft()
+            self.__put_internal(item)
+            future_set_result_unless_cancelled(putter, None)
+            return self._get()
+        elif self.qsize():
+            return self._get()
+        else:
+            raise QueueEmpty
+
+    def task_done(self) -> None:
+        """Indicate that a formerly enqueued task is complete.
+
+        Used by queue consumers. For each `.get` used to fetch a task, a
+        subsequent call to `.task_done` tells the queue that the processing
+        on the task is complete.
+
+        If a `.join` is blocking, it resumes when all items have been
+        processed; that is, when every `.put` is matched by a `.task_done`.
+
+        Raises `ValueError` if called more times than `.put`.
+        """
+        if self._unfinished_tasks <= 0:
+            raise ValueError("task_done() called too many times")
+        self._unfinished_tasks -= 1
+        if self._unfinished_tasks == 0:
+            self._finished.set()
+
+    def join(
+        self, timeout: Optional[Union[float, datetime.timedelta]] = None
+    ) -> Awaitable[None]:
+        """Block until all items in the queue are processed.
+
+        Returns an awaitable, which raises `tornado.util.TimeoutError` after a
+        timeout.
+        """
+        return self._finished.wait(timeout)
+
+    def __aiter__(self) -> _QueueIterator[_T]:
+        return _QueueIterator(self)
+
+    # These three are overridable in subclasses.
+    def _init(self) -> None:
+        self._queue = collections.deque()
+
+    def _get(self) -> _T:
+        return self._queue.popleft()
+
+    def _put(self, item: _T) -> None:
+        self._queue.append(item)
+
+    # End of the overridable methods.
+
+    def __put_internal(self, item: _T) -> None:
+        self._unfinished_tasks += 1
+        self._finished.clear()
+        self._put(item)
+
+    def _consume_expired(self) -> None:
+        # Remove timed-out waiters.
+        while self._putters and self._putters[0][1].done():
+            self._putters.popleft()
+
+        while self._getters and self._getters[0].done():
+            self._getters.popleft()
+
+    def __repr__(self) -> str:
+        return "<%s at %s %s>" % (type(self).__name__, hex(id(self)), self._format())
+
+    def __str__(self) -> str:
+        return "<%s %s>" % (type(self).__name__, self._format())
+
+    def _format(self) -> str:
+        result = "maxsize=%r" % (self.maxsize,)
+        if getattr(self, "_queue", None):
+            result += " queue=%r" % self._queue
+        if self._getters:
+            result += " getters[%s]" % len(self._getters)
+        if self._putters:
+            result += " putters[%s]" % len(self._putters)
+        if self._unfinished_tasks:
+            result += " tasks=%s" % self._unfinished_tasks
+        return result
+
+
+class PriorityQueue(Queue):
+    """A `.Queue` that retrieves entries in priority order, lowest first.
+
+    Entries are typically tuples like ``(priority number, data)``.
+
+    .. testcode::
+
+        import asyncio
+        from tornado.queues import PriorityQueue
+
+        async def main():
+            q = PriorityQueue()
+            q.put((1, 'medium-priority item'))
+            q.put((0, 'high-priority item'))
+            q.put((10, 'low-priority item'))
+
+            print(await q.get())
+            print(await q.get())
+            print(await q.get())
+
+        asyncio.run(main())
+
+    .. testoutput::
+
+        (0, 'high-priority item')
+        (1, 'medium-priority item')
+        (10, 'low-priority item')
+    """
+
+    def _init(self) -> None:
+        self._queue = []
+
+    def _put(self, item: _T) -> None:
+        heapq.heappush(self._queue, item)
+
+    def _get(self) -> _T:  # type: ignore[type-var]
+        return heapq.heappop(self._queue)
+
+
+class LifoQueue(Queue):
+    """A `.Queue` that retrieves the most recently put items first.
+
+    .. testcode::
+
+        import asyncio
+        from tornado.queues import LifoQueue
+
+        async def main():
+            q = LifoQueue()
+            q.put(3)
+            q.put(2)
+            q.put(1)
+
+            print(await q.get())
+            print(await q.get())
+            print(await q.get())
+
+        asyncio.run(main())
+
+    .. testoutput::
+
+        1
+        2
+        3
+    """
+
+    def _init(self) -> None:
+        self._queue = []
+
+    def _put(self, item: _T) -> None:
+        self._queue.append(item)
+
+    def _get(self) -> _T:  # type: ignore[type-var]
+        return self._queue.pop()
diff --git a/venv/lib/python3.9/site-packages/tornado/routing.py b/venv/lib/python3.9/site-packages/tornado/routing.py
new file mode 100644
index 00000000..a145d719
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/routing.py
@@ -0,0 +1,717 @@
+# Copyright 2015 The Tornado Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Flexible routing implementation.
+
+Tornado routes HTTP requests to appropriate handlers using `Router`
+class implementations. The `tornado.web.Application` class is a
+`Router` implementation and may be used directly, or the classes in
+this module may be used for additional flexibility. The `RuleRouter`
+class can match on more criteria than `.Application`, or the `Router`
+interface can be subclassed for maximum customization.
+
+`Router` interface extends `~.httputil.HTTPServerConnectionDelegate`
+to provide additional routing capabilities. This also means that any
+`Router` implementation can be used directly as a ``request_callback``
+for `~.httpserver.HTTPServer` constructor.
+
+`Router` subclass must implement a ``find_handler`` method to provide
+a suitable `~.httputil.HTTPMessageDelegate` instance to handle the
+request:
+
+.. code-block:: python
+
+    class CustomRouter(Router):
+        def find_handler(self, request, **kwargs):
+            # some routing logic providing a suitable HTTPMessageDelegate instance
+            return MessageDelegate(request.connection)
+
+    class MessageDelegate(HTTPMessageDelegate):
+        def __init__(self, connection):
+            self.connection = connection
+
+        def finish(self):
+            self.connection.write_headers(
+                ResponseStartLine("HTTP/1.1", 200, "OK"),
+                HTTPHeaders({"Content-Length": "2"}),
+                b"OK")
+            self.connection.finish()
+
+    router = CustomRouter()
+    server = HTTPServer(router)
+
+The main responsibility of `Router` implementation is to provide a
+mapping from a request to `~.httputil.HTTPMessageDelegate` instance
+that will handle this request. In the example above we can see that
+routing is possible even without instantiating an `~.web.Application`.
+
+For routing to `~.web.RequestHandler` implementations we need an
+`~.web.Application` instance. `~.web.Application.get_handler_delegate`
+provides a convenient way to create `~.httputil.HTTPMessageDelegate`
+for a given request and `~.web.RequestHandler`.
+
+Here is a simple example of how we can we route to
+`~.web.RequestHandler` subclasses by HTTP method:
+
+.. code-block:: python
+
+    resources = {}
+
+    class GetResource(RequestHandler):
+        def get(self, path):
+            if path not in resources:
+                raise HTTPError(404)
+
+            self.finish(resources[path])
+
+    class PostResource(RequestHandler):
+        def post(self, path):
+            resources[path] = self.request.body
+
+    class HTTPMethodRouter(Router):
+        def __init__(self, app):
+            self.app = app
+
+        def find_handler(self, request, **kwargs):
+            handler = GetResource if request.method == "GET" else PostResource
+            return self.app.get_handler_delegate(request, handler, path_args=[request.path])
+
+    router = HTTPMethodRouter(Application())
+    server = HTTPServer(router)
+
+`ReversibleRouter` interface adds the ability to distinguish between
+the routes and reverse them to the original urls using route's name
+and additional arguments. `~.web.Application` is itself an
+implementation of `ReversibleRouter` class.
+
+`RuleRouter` and `ReversibleRuleRouter` are implementations of
+`Router` and `ReversibleRouter` interfaces and can be used for
+creating rule-based routing configurations.
+
+Rules are instances of `Rule` class. They contain a `Matcher`, which
+provides the logic for determining whether the rule is a match for a
+particular request and a target, which can be one of the following.
+
+1) An instance of `~.httputil.HTTPServerConnectionDelegate`:
+
+.. code-block:: python
+
+    router = RuleRouter([
+        Rule(PathMatches("/handler"), ConnectionDelegate()),
+        # ... more rules
+    ])
+
+    class ConnectionDelegate(HTTPServerConnectionDelegate):
+        def start_request(self, server_conn, request_conn):
+            return MessageDelegate(request_conn)
+
+2) A callable accepting a single argument of `~.httputil.HTTPServerRequest` type:
+
+.. code-block:: python
+
+    router = RuleRouter([
+        Rule(PathMatches("/callable"), request_callable)
+    ])
+
+    def request_callable(request):
+        request.write(b"HTTP/1.1 200 OK\\r\\nContent-Length: 2\\r\\n\\r\\nOK")
+        request.finish()
+
+3) Another `Router` instance:
+
+.. code-block:: python
+
+    router = RuleRouter([
+        Rule(PathMatches("/router.*"), CustomRouter())
+    ])
+
+Of course a nested `RuleRouter` or a `~.web.Application` is allowed:
+
+.. code-block:: python
+
+    router = RuleRouter([
+        Rule(HostMatches("example.com"), RuleRouter([
+            Rule(PathMatches("/app1/.*"), Application([(r"/app1/handler", Handler)])),
+        ]))
+    ])
+
+    server = HTTPServer(router)
+
+In the example below `RuleRouter` is used to route between applications:
+
+.. code-block:: python
+
+    app1 = Application([
+        (r"/app1/handler", Handler1),
+        # other handlers ...
+    ])
+
+    app2 = Application([
+        (r"/app2/handler", Handler2),
+        # other handlers ...
+    ])
+
+    router = RuleRouter([
+        Rule(PathMatches("/app1.*"), app1),
+        Rule(PathMatches("/app2.*"), app2)
+    ])
+
+    server = HTTPServer(router)
+
+For more information on application-level routing see docs for `~.web.Application`.
+
+.. versionadded:: 4.5
+
+"""
+
+import re
+from functools import partial
+
+from tornado import httputil
+from tornado.httpserver import _CallableAdapter
+from tornado.escape import url_escape, url_unescape, utf8
+from tornado.log import app_log
+from tornado.util import basestring_type, import_object, re_unescape, unicode_type
+
+from typing import Any, Union, Optional, Awaitable, List, Dict, Pattern, Tuple, overload
+
+
+class Router(httputil.HTTPServerConnectionDelegate):
+    """Abstract router interface."""
+
+    def find_handler(
+        self, request: httputil.HTTPServerRequest, **kwargs: Any
+    ) -> Optional[httputil.HTTPMessageDelegate]:
+        """Must be implemented to return an appropriate instance of `~.httputil.HTTPMessageDelegate`
+        that can serve the request.
+        Routing implementations may pass additional kwargs to extend the routing logic.
+
+        :arg httputil.HTTPServerRequest request: current HTTP request.
+        :arg kwargs: additional keyword arguments passed by routing implementation.
+        :returns: an instance of `~.httputil.HTTPMessageDelegate` that will be used to
+            process the request.
+        """
+        raise NotImplementedError()
+
+    def start_request(
+        self, server_conn: object, request_conn: httputil.HTTPConnection
+    ) -> httputil.HTTPMessageDelegate:
+        return _RoutingDelegate(self, server_conn, request_conn)
+
+
+class ReversibleRouter(Router):
+    """Abstract router interface for routers that can handle named routes
+    and support reversing them to original urls.
+    """
+
+    def reverse_url(self, name: str, *args: Any) -> Optional[str]:
+        """Returns url string for a given route name and arguments
+        or ``None`` if no match is found.
+
+        :arg str name: route name.
+        :arg args: url parameters.
+        :returns: parametrized url string for a given route name (or ``None``).
+        """
+        raise NotImplementedError()
+
+
+class _RoutingDelegate(httputil.HTTPMessageDelegate):
+    def __init__(
+        self, router: Router, server_conn: object, request_conn: httputil.HTTPConnection
+    ) -> None:
+        self.server_conn = server_conn
+        self.request_conn = request_conn
+        self.delegate = None  # type: Optional[httputil.HTTPMessageDelegate]
+        self.router = router  # type: Router
+
+    def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        assert isinstance(start_line, httputil.RequestStartLine)
+        request = httputil.HTTPServerRequest(
+            connection=self.request_conn,
+            server_connection=self.server_conn,
+            start_line=start_line,
+            headers=headers,
+        )
+
+        self.delegate = self.router.find_handler(request)
+        if self.delegate is None:
+            app_log.debug(
+                "Delegate for %s %s request not found",
+                start_line.method,
+                start_line.path,
+            )
+            self.delegate = _DefaultMessageDelegate(self.request_conn)
+
+        return self.delegate.headers_received(start_line, headers)
+
+    def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
+        assert self.delegate is not None
+        return self.delegate.data_received(chunk)
+
+    def finish(self) -> None:
+        assert self.delegate is not None
+        self.delegate.finish()
+
+    def on_connection_close(self) -> None:
+        assert self.delegate is not None
+        self.delegate.on_connection_close()
+
+
+class _DefaultMessageDelegate(httputil.HTTPMessageDelegate):
+    def __init__(self, connection: httputil.HTTPConnection) -> None:
+        self.connection = connection
+
+    def finish(self) -> None:
+        self.connection.write_headers(
+            httputil.ResponseStartLine("HTTP/1.1", 404, "Not Found"),
+            httputil.HTTPHeaders(),
+        )
+        self.connection.finish()
+
+
+# _RuleList can either contain pre-constructed Rules or a sequence of
+# arguments to be passed to the Rule constructor.
+_RuleList = List[
+    Union[
+        "Rule",
+        List[Any],  # Can't do detailed typechecking of lists.
+        Tuple[Union[str, "Matcher"], Any],
+        Tuple[Union[str, "Matcher"], Any, Dict[str, Any]],
+        Tuple[Union[str, "Matcher"], Any, Dict[str, Any], str],
+    ]
+]
+
+
+class RuleRouter(Router):
+    """Rule-based router implementation."""
+
+    def __init__(self, rules: Optional[_RuleList] = None) -> None:
+        """Constructs a router from an ordered list of rules::
+
+            RuleRouter([
+                Rule(PathMatches("/handler"), Target),
+                # ... more rules
+            ])
+
+        You can also omit explicit `Rule` constructor and use tuples of arguments::
+
+            RuleRouter([
+                (PathMatches("/handler"), Target),
+            ])
+
+        `PathMatches` is a default matcher, so the example above can be simplified::
+
+            RuleRouter([
+                ("/handler", Target),
+            ])
+
+        In the examples above, ``Target`` can be a nested `Router` instance, an instance of
+        `~.httputil.HTTPServerConnectionDelegate` or an old-style callable,
+        accepting a request argument.
+
+        :arg rules: a list of `Rule` instances or tuples of `Rule`
+            constructor arguments.
+        """
+        self.rules = []  # type: List[Rule]
+        if rules:
+            self.add_rules(rules)
+
+    def add_rules(self, rules: _RuleList) -> None:
+        """Appends new rules to the router.
+
+        :arg rules: a list of Rule instances (or tuples of arguments, which are
+            passed to Rule constructor).
+        """
+        for rule in rules:
+            if isinstance(rule, (tuple, list)):
+                assert len(rule) in (2, 3, 4)
+                if isinstance(rule[0], basestring_type):
+                    rule = Rule(PathMatches(rule[0]), *rule[1:])
+                else:
+                    rule = Rule(*rule)
+
+            self.rules.append(self.process_rule(rule))
+
+    def process_rule(self, rule: "Rule") -> "Rule":
+        """Override this method for additional preprocessing of each rule.
+
+        :arg Rule rule: a rule to be processed.
+        :returns: the same or modified Rule instance.
+        """
+        return rule
+
+    def find_handler(
+        self, request: httputil.HTTPServerRequest, **kwargs: Any
+    ) -> Optional[httputil.HTTPMessageDelegate]:
+        for rule in self.rules:
+            target_params = rule.matcher.match(request)
+            if target_params is not None:
+                if rule.target_kwargs:
+                    target_params["target_kwargs"] = rule.target_kwargs
+
+                delegate = self.get_target_delegate(
+                    rule.target, request, **target_params
+                )
+
+                if delegate is not None:
+                    return delegate
+
+        return None
+
+    def get_target_delegate(
+        self, target: Any, request: httputil.HTTPServerRequest, **target_params: Any
+    ) -> Optional[httputil.HTTPMessageDelegate]:
+        """Returns an instance of `~.httputil.HTTPMessageDelegate` for a
+        Rule's target. This method is called by `~.find_handler` and can be
+        extended to provide additional target types.
+
+        :arg target: a Rule's target.
+        :arg httputil.HTTPServerRequest request: current request.
+        :arg target_params: additional parameters that can be useful
+            for `~.httputil.HTTPMessageDelegate` creation.
+        """
+        if isinstance(target, Router):
+            return target.find_handler(request, **target_params)
+
+        elif isinstance(target, httputil.HTTPServerConnectionDelegate):
+            assert request.connection is not None
+            return target.start_request(request.server_connection, request.connection)
+
+        elif callable(target):
+            assert request.connection is not None
+            return _CallableAdapter(
+                partial(target, **target_params), request.connection
+            )
+
+        return None
+
+
+class ReversibleRuleRouter(ReversibleRouter, RuleRouter):
+    """A rule-based router that implements ``reverse_url`` method.
+
+    Each rule added to this router may have a ``name`` attribute that can be
+    used to reconstruct an original uri. The actual reconstruction takes place
+    in a rule's matcher (see `Matcher.reverse`).
+    """
+
+    def __init__(self, rules: Optional[_RuleList] = None) -> None:
+        self.named_rules = {}  # type: Dict[str, Any]
+        super().__init__(rules)
+
+    def process_rule(self, rule: "Rule") -> "Rule":
+        rule = super().process_rule(rule)
+
+        if rule.name:
+            if rule.name in self.named_rules:
+                app_log.warning(
+                    "Multiple handlers named %s; replacing previous value", rule.name
+                )
+            self.named_rules[rule.name] = rule
+
+        return rule
+
+    def reverse_url(self, name: str, *args: Any) -> Optional[str]:
+        if name in self.named_rules:
+            return self.named_rules[name].matcher.reverse(*args)
+
+        for rule in self.rules:
+            if isinstance(rule.target, ReversibleRouter):
+                reversed_url = rule.target.reverse_url(name, *args)
+                if reversed_url is not None:
+                    return reversed_url
+
+        return None
+
+
+class Rule(object):
+    """A routing rule."""
+
+    def __init__(
+        self,
+        matcher: "Matcher",
+        target: Any,
+        target_kwargs: Optional[Dict[str, Any]] = None,
+        name: Optional[str] = None,
+    ) -> None:
+        """Constructs a Rule instance.
+
+        :arg Matcher matcher: a `Matcher` instance used for determining
+            whether the rule should be considered a match for a specific
+            request.
+        :arg target: a Rule's target (typically a ``RequestHandler`` or
+            `~.httputil.HTTPServerConnectionDelegate` subclass or even a nested `Router`,
+            depending on routing implementation).
+        :arg dict target_kwargs: a dict of parameters that can be useful
+            at the moment of target instantiation (for example, ``status_code``
+            for a ``RequestHandler`` subclass). They end up in
+            ``target_params['target_kwargs']`` of `RuleRouter.get_target_delegate`
+            method.
+        :arg str name: the name of the rule that can be used to find it
+            in `ReversibleRouter.reverse_url` implementation.
+        """
+        if isinstance(target, str):
+            # import the Module and instantiate the class
+            # Must be a fully qualified name (module.ClassName)
+            target = import_object(target)
+
+        self.matcher = matcher  # type: Matcher
+        self.target = target
+        self.target_kwargs = target_kwargs if target_kwargs else {}
+        self.name = name
+
+    def reverse(self, *args: Any) -> Optional[str]:
+        return self.matcher.reverse(*args)
+
+    def __repr__(self) -> str:
+        return "%s(%r, %s, kwargs=%r, name=%r)" % (
+            self.__class__.__name__,
+            self.matcher,
+            self.target,
+            self.target_kwargs,
+            self.name,
+        )
+
+
+class Matcher(object):
+    """Represents a matcher for request features."""
+
+    def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
+        """Matches current instance against the request.
+
+        :arg httputil.HTTPServerRequest request: current HTTP request
+        :returns: a dict of parameters to be passed to the target handler
+            (for example, ``handler_kwargs``, ``path_args``, ``path_kwargs``
+            can be passed for proper `~.web.RequestHandler` instantiation).
+            An empty dict is a valid (and common) return value to indicate a match
+            when the argument-passing features are not used.
+            ``None`` must be returned to indicate that there is no match."""
+        raise NotImplementedError()
+
+    def reverse(self, *args: Any) -> Optional[str]:
+        """Reconstructs full url from matcher instance and additional arguments."""
+        return None
+
+
+class AnyMatches(Matcher):
+    """Matches any request."""
+
+    def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
+        return {}
+
+
+class HostMatches(Matcher):
+    """Matches requests from hosts specified by ``host_pattern`` regex."""
+
+    def __init__(self, host_pattern: Union[str, Pattern]) -> None:
+        if isinstance(host_pattern, basestring_type):
+            if not host_pattern.endswith("$"):
+                host_pattern += "$"
+            self.host_pattern = re.compile(host_pattern)
+        else:
+            self.host_pattern = host_pattern
+
+    def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
+        if self.host_pattern.match(request.host_name):
+            return {}
+
+        return None
+
+
+class DefaultHostMatches(Matcher):
+    """Matches requests from host that is equal to application's default_host.
+    Always returns no match if ``X-Real-Ip`` header is present.
+    """
+
+    def __init__(self, application: Any, host_pattern: Pattern) -> None:
+        self.application = application
+        self.host_pattern = host_pattern
+
+    def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
+        # Look for default host if not behind load balancer (for debugging)
+        if "X-Real-Ip" not in request.headers:
+            if self.host_pattern.match(self.application.default_host):
+                return {}
+        return None
+
+
+class PathMatches(Matcher):
+    """Matches requests with paths specified by ``path_pattern`` regex."""
+
+    def __init__(self, path_pattern: Union[str, Pattern]) -> None:
+        if isinstance(path_pattern, basestring_type):
+            if not path_pattern.endswith("$"):
+                path_pattern += "$"
+            self.regex = re.compile(path_pattern)
+        else:
+            self.regex = path_pattern
+
+        assert len(self.regex.groupindex) in (0, self.regex.groups), (
+            "groups in url regexes must either be all named or all "
+            "positional: %r" % self.regex.pattern
+        )
+
+        self._path, self._group_count = self._find_groups()
+
+    def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
+        match = self.regex.match(request.path)
+        if match is None:
+            return None
+        if not self.regex.groups:
+            return {}
+
+        path_args = []  # type: List[bytes]
+        path_kwargs = {}  # type: Dict[str, bytes]
+
+        # Pass matched groups to the handler.  Since
+        # match.groups() includes both named and
+        # unnamed groups, we want to use either groups
+        # or groupdict but not both.
+        if self.regex.groupindex:
+            path_kwargs = dict(
+                (str(k), _unquote_or_none(v)) for (k, v) in match.groupdict().items()
+            )
+        else:
+            path_args = [_unquote_or_none(s) for s in match.groups()]
+
+        return dict(path_args=path_args, path_kwargs=path_kwargs)
+
+    def reverse(self, *args: Any) -> Optional[str]:
+        if self._path is None:
+            raise ValueError("Cannot reverse url regex " + self.regex.pattern)
+        assert len(args) == self._group_count, (
+            "required number of arguments " "not found"
+        )
+        if not len(args):
+            return self._path
+        converted_args = []
+        for a in args:
+            if not isinstance(a, (unicode_type, bytes)):
+                a = str(a)
+            converted_args.append(url_escape(utf8(a), plus=False))
+        return self._path % tuple(converted_args)
+
+    def _find_groups(self) -> Tuple[Optional[str], Optional[int]]:
+        """Returns a tuple (reverse string, group count) for a url.
+
+        For example: Given the url pattern /([0-9]{4})/([a-z-]+)/, this method
+        would return ('/%s/%s/', 2).
+        """
+        pattern = self.regex.pattern
+        if pattern.startswith("^"):
+            pattern = pattern[1:]
+        if pattern.endswith("$"):
+            pattern = pattern[:-1]
+
+        if self.regex.groups != pattern.count("("):
+            # The pattern is too complicated for our simplistic matching,
+            # so we can't support reversing it.
+            return None, None
+
+        pieces = []
+        for fragment in pattern.split("("):
+            if ")" in fragment:
+                paren_loc = fragment.index(")")
+                if paren_loc >= 0:
+                    try:
+                        unescaped_fragment = re_unescape(fragment[paren_loc + 1 :])
+                    except ValueError:
+                        # If we can't unescape part of it, we can't
+                        # reverse this url.
+                        return (None, None)
+                    pieces.append("%s" + unescaped_fragment)
+            else:
+                try:
+                    unescaped_fragment = re_unescape(fragment)
+                except ValueError:
+                    # If we can't unescape part of it, we can't
+                    # reverse this url.
+                    return (None, None)
+                pieces.append(unescaped_fragment)
+
+        return "".join(pieces), self.regex.groups
+
+
+class URLSpec(Rule):
+    """Specifies mappings between URLs and handlers.
+
+    .. versionchanged: 4.5
+       `URLSpec` is now a subclass of a `Rule` with `PathMatches` matcher and is preserved for
+       backwards compatibility.
+    """
+
+    def __init__(
+        self,
+        pattern: Union[str, Pattern],
+        handler: Any,
+        kwargs: Optional[Dict[str, Any]] = None,
+        name: Optional[str] = None,
+    ) -> None:
+        """Parameters:
+
+        * ``pattern``: Regular expression to be matched. Any capturing
+          groups in the regex will be passed in to the handler's
+          get/post/etc methods as arguments (by keyword if named, by
+          position if unnamed. Named and unnamed capturing groups
+          may not be mixed in the same rule).
+
+        * ``handler``: `~.web.RequestHandler` subclass to be invoked.
+
+        * ``kwargs`` (optional): A dictionary of additional arguments
+          to be passed to the handler's constructor.
+
+        * ``name`` (optional): A name for this handler.  Used by
+          `~.web.Application.reverse_url`.
+
+        """
+        matcher = PathMatches(pattern)
+        super().__init__(matcher, handler, kwargs, name)
+
+        self.regex = matcher.regex
+        self.handler_class = self.target
+        self.kwargs = kwargs
+
+    def __repr__(self) -> str:
+        return "%s(%r, %s, kwargs=%r, name=%r)" % (
+            self.__class__.__name__,
+            self.regex.pattern,
+            self.handler_class,
+            self.kwargs,
+            self.name,
+        )
+
+
+@overload
+def _unquote_or_none(s: str) -> bytes:
+    pass
+
+
+@overload  # noqa: F811
+def _unquote_or_none(s: None) -> None:
+    pass
+
+
+def _unquote_or_none(s: Optional[str]) -> Optional[bytes]:  # noqa: F811
+    """None-safe wrapper around url_unescape to handle unmatched optional
+    groups correctly.
+
+    Note that args are passed as bytes so the handler can decide what
+    encoding to use.
+    """
+    if s is None:
+        return s
+    return url_unescape(s, encoding=None, plus=False)
diff --git a/venv/lib/python3.9/site-packages/tornado/simple_httpclient.py b/venv/lib/python3.9/site-packages/tornado/simple_httpclient.py
new file mode 100644
index 00000000..2460863f
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/simple_httpclient.py
@@ -0,0 +1,704 @@
+from tornado.escape import _unicode
+from tornado import gen, version
+from tornado.httpclient import (
+    HTTPResponse,
+    HTTPError,
+    AsyncHTTPClient,
+    main,
+    _RequestProxy,
+    HTTPRequest,
+)
+from tornado import httputil
+from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
+from tornado.ioloop import IOLoop
+from tornado.iostream import StreamClosedError, IOStream
+from tornado.netutil import (
+    Resolver,
+    OverrideResolver,
+    _client_ssl_defaults,
+    is_valid_ip,
+)
+from tornado.log import gen_log
+from tornado.tcpclient import TCPClient
+
+import base64
+import collections
+import copy
+import functools
+import re
+import socket
+import ssl
+import sys
+import time
+from io import BytesIO
+import urllib.parse
+
+from typing import Dict, Any, Callable, Optional, Type, Union
+from types import TracebackType
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Deque, Tuple, List  # noqa: F401
+
+
+class HTTPTimeoutError(HTTPError):
+    """Error raised by SimpleAsyncHTTPClient on timeout.
+
+    For historical reasons, this is a subclass of `.HTTPClientError`
+    which simulates a response code of 599.
+
+    .. versionadded:: 5.1
+    """
+
+    def __init__(self, message: str) -> None:
+        super().__init__(599, message=message)
+
+    def __str__(self) -> str:
+        return self.message or "Timeout"
+
+
+class HTTPStreamClosedError(HTTPError):
+    """Error raised by SimpleAsyncHTTPClient when the underlying stream is closed.
+
+    When a more specific exception is available (such as `ConnectionResetError`),
+    it may be raised instead of this one.
+
+    For historical reasons, this is a subclass of `.HTTPClientError`
+    which simulates a response code of 599.
+
+    .. versionadded:: 5.1
+    """
+
+    def __init__(self, message: str) -> None:
+        super().__init__(599, message=message)
+
+    def __str__(self) -> str:
+        return self.message or "Stream closed"
+
+
+class SimpleAsyncHTTPClient(AsyncHTTPClient):
+    """Non-blocking HTTP client with no external dependencies.
+
+    This class implements an HTTP 1.1 client on top of Tornado's IOStreams.
+    Some features found in the curl-based AsyncHTTPClient are not yet
+    supported.  In particular, proxies are not supported, connections
+    are not reused, and callers cannot select the network interface to be
+    used.
+
+    This implementation supports the following arguments, which can be passed
+    to ``configure()`` to control the global singleton, or to the constructor
+    when ``force_instance=True``.
+
+    ``max_clients`` is the number of concurrent requests that can be
+    in progress; when this limit is reached additional requests will be
+    queued. Note that time spent waiting in this queue still counts
+    against the ``request_timeout``.
+
+    ``defaults`` is a dict of parameters that will be used as defaults on all
+    `.HTTPRequest` objects submitted to this client.
+
+    ``hostname_mapping`` is a dictionary mapping hostnames to IP addresses.
+    It can be used to make local DNS changes when modifying system-wide
+    settings like ``/etc/hosts`` is not possible or desirable (e.g. in
+    unittests). ``resolver`` is similar, but using the `.Resolver` interface
+    instead of a simple mapping.
+
+    ``max_buffer_size`` (default 100MB) is the number of bytes
+    that can be read into memory at once. ``max_body_size``
+    (defaults to ``max_buffer_size``) is the largest response body
+    that the client will accept.  Without a
+    ``streaming_callback``, the smaller of these two limits
+    applies; with a ``streaming_callback`` only ``max_body_size``
+    does.
+
+    .. versionchanged:: 4.2
+        Added the ``max_body_size`` argument.
+    """
+
+    def initialize(  # type: ignore
+        self,
+        max_clients: int = 10,
+        hostname_mapping: Optional[Dict[str, str]] = None,
+        max_buffer_size: int = 104857600,
+        resolver: Optional[Resolver] = None,
+        defaults: Optional[Dict[str, Any]] = None,
+        max_header_size: Optional[int] = None,
+        max_body_size: Optional[int] = None,
+    ) -> None:
+        super().initialize(defaults=defaults)
+        self.max_clients = max_clients
+        self.queue = (
+            collections.deque()
+        )  # type: Deque[Tuple[object, HTTPRequest, Callable[[HTTPResponse], None]]]
+        self.active = (
+            {}
+        )  # type: Dict[object, Tuple[HTTPRequest, Callable[[HTTPResponse], None]]]
+        self.waiting = (
+            {}
+        )  # type: Dict[object, Tuple[HTTPRequest, Callable[[HTTPResponse], None], object]]
+        self.max_buffer_size = max_buffer_size
+        self.max_header_size = max_header_size
+        self.max_body_size = max_body_size
+        # TCPClient could create a Resolver for us, but we have to do it
+        # ourselves to support hostname_mapping.
+        if resolver:
+            self.resolver = resolver
+            self.own_resolver = False
+        else:
+            self.resolver = Resolver()
+            self.own_resolver = True
+        if hostname_mapping is not None:
+            self.resolver = OverrideResolver(
+                resolver=self.resolver, mapping=hostname_mapping
+            )
+        self.tcp_client = TCPClient(resolver=self.resolver)
+
+    def close(self) -> None:
+        super().close()
+        if self.own_resolver:
+            self.resolver.close()
+        self.tcp_client.close()
+
+    def fetch_impl(
+        self, request: HTTPRequest, callback: Callable[[HTTPResponse], None]
+    ) -> None:
+        key = object()
+        self.queue.append((key, request, callback))
+        assert request.connect_timeout is not None
+        assert request.request_timeout is not None
+        timeout_handle = None
+        if len(self.active) >= self.max_clients:
+            timeout = (
+                min(request.connect_timeout, request.request_timeout)
+                or request.connect_timeout
+                or request.request_timeout
+            )  # min but skip zero
+            if timeout:
+                timeout_handle = self.io_loop.add_timeout(
+                    self.io_loop.time() + timeout,
+                    functools.partial(self._on_timeout, key, "in request queue"),
+                )
+        self.waiting[key] = (request, callback, timeout_handle)
+        self._process_queue()
+        if self.queue:
+            gen_log.debug(
+                "max_clients limit reached, request queued. "
+                "%d active, %d queued requests." % (len(self.active), len(self.queue))
+            )
+
+    def _process_queue(self) -> None:
+        while self.queue and len(self.active) < self.max_clients:
+            key, request, callback = self.queue.popleft()
+            if key not in self.waiting:
+                continue
+            self._remove_timeout(key)
+            self.active[key] = (request, callback)
+            release_callback = functools.partial(self._release_fetch, key)
+            self._handle_request(request, release_callback, callback)
+
+    def _connection_class(self) -> type:
+        return _HTTPConnection
+
+    def _handle_request(
+        self,
+        request: HTTPRequest,
+        release_callback: Callable[[], None],
+        final_callback: Callable[[HTTPResponse], None],
+    ) -> None:
+        self._connection_class()(
+            self,
+            request,
+            release_callback,
+            final_callback,
+            self.max_buffer_size,
+            self.tcp_client,
+            self.max_header_size,
+            self.max_body_size,
+        )
+
+    def _release_fetch(self, key: object) -> None:
+        del self.active[key]
+        self._process_queue()
+
+    def _remove_timeout(self, key: object) -> None:
+        if key in self.waiting:
+            request, callback, timeout_handle = self.waiting[key]
+            if timeout_handle is not None:
+                self.io_loop.remove_timeout(timeout_handle)
+            del self.waiting[key]
+
+    def _on_timeout(self, key: object, info: Optional[str] = None) -> None:
+        """Timeout callback of request.
+
+        Construct a timeout HTTPResponse when a timeout occurs.
+
+        :arg object key: A simple object to mark the request.
+        :info string key: More detailed timeout information.
+        """
+        request, callback, timeout_handle = self.waiting[key]
+        self.queue.remove((key, request, callback))
+
+        error_message = "Timeout {0}".format(info) if info else "Timeout"
+        timeout_response = HTTPResponse(
+            request,
+            599,
+            error=HTTPTimeoutError(error_message),
+            request_time=self.io_loop.time() - request.start_time,
+        )
+        self.io_loop.add_callback(callback, timeout_response)
+        del self.waiting[key]
+
+
+class _HTTPConnection(httputil.HTTPMessageDelegate):
+    _SUPPORTED_METHODS = set(
+        ["GET", "HEAD", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"]
+    )
+
+    def __init__(
+        self,
+        client: Optional[SimpleAsyncHTTPClient],
+        request: HTTPRequest,
+        release_callback: Callable[[], None],
+        final_callback: Callable[[HTTPResponse], None],
+        max_buffer_size: int,
+        tcp_client: TCPClient,
+        max_header_size: int,
+        max_body_size: int,
+    ) -> None:
+        self.io_loop = IOLoop.current()
+        self.start_time = self.io_loop.time()
+        self.start_wall_time = time.time()
+        self.client = client
+        self.request = request
+        self.release_callback = release_callback
+        self.final_callback = final_callback
+        self.max_buffer_size = max_buffer_size
+        self.tcp_client = tcp_client
+        self.max_header_size = max_header_size
+        self.max_body_size = max_body_size
+        self.code = None  # type: Optional[int]
+        self.headers = None  # type: Optional[httputil.HTTPHeaders]
+        self.chunks = []  # type: List[bytes]
+        self._decompressor = None
+        # Timeout handle returned by IOLoop.add_timeout
+        self._timeout = None  # type: object
+        self._sockaddr = None
+        IOLoop.current().add_future(
+            gen.convert_yielded(self.run()), lambda f: f.result()
+        )
+
+    async def run(self) -> None:
+        try:
+            self.parsed = urllib.parse.urlsplit(_unicode(self.request.url))
+            if self.parsed.scheme not in ("http", "https"):
+                raise ValueError("Unsupported url scheme: %s" % self.request.url)
+            # urlsplit results have hostname and port results, but they
+            # didn't support ipv6 literals until python 2.7.
+            netloc = self.parsed.netloc
+            if "@" in netloc:
+                userpass, _, netloc = netloc.rpartition("@")
+            host, port = httputil.split_host_and_port(netloc)
+            if port is None:
+                port = 443 if self.parsed.scheme == "https" else 80
+            if re.match(r"^\[.*\]$", host):
+                # raw ipv6 addresses in urls are enclosed in brackets
+                host = host[1:-1]
+            self.parsed_hostname = host  # save final host for _on_connect
+
+            if self.request.allow_ipv6 is False:
+                af = socket.AF_INET
+            else:
+                af = socket.AF_UNSPEC
+
+            ssl_options = self._get_ssl_options(self.parsed.scheme)
+
+            source_ip = None
+            if self.request.network_interface:
+                if is_valid_ip(self.request.network_interface):
+                    source_ip = self.request.network_interface
+                else:
+                    raise ValueError(
+                        "Unrecognized IPv4 or IPv6 address for network_interface, got %r"
+                        % (self.request.network_interface,)
+                    )
+
+            if self.request.connect_timeout and self.request.request_timeout:
+                timeout = min(
+                    self.request.connect_timeout, self.request.request_timeout
+                )
+            elif self.request.connect_timeout:
+                timeout = self.request.connect_timeout
+            elif self.request.request_timeout:
+                timeout = self.request.request_timeout
+            else:
+                timeout = 0
+            if timeout:
+                self._timeout = self.io_loop.add_timeout(
+                    self.start_time + timeout,
+                    functools.partial(self._on_timeout, "while connecting"),
+                )
+            stream = await self.tcp_client.connect(
+                host,
+                port,
+                af=af,
+                ssl_options=ssl_options,
+                max_buffer_size=self.max_buffer_size,
+                source_ip=source_ip,
+            )
+
+            if self.final_callback is None:
+                # final_callback is cleared if we've hit our timeout.
+                stream.close()
+                return
+            self.stream = stream
+            self.stream.set_close_callback(self.on_connection_close)
+            self._remove_timeout()
+            if self.final_callback is None:
+                return
+            if self.request.request_timeout:
+                self._timeout = self.io_loop.add_timeout(
+                    self.start_time + self.request.request_timeout,
+                    functools.partial(self._on_timeout, "during request"),
+                )
+            if (
+                self.request.method not in self._SUPPORTED_METHODS
+                and not self.request.allow_nonstandard_methods
+            ):
+                raise KeyError("unknown method %s" % self.request.method)
+            for key in (
+                "proxy_host",
+                "proxy_port",
+                "proxy_username",
+                "proxy_password",
+                "proxy_auth_mode",
+            ):
+                if getattr(self.request, key, None):
+                    raise NotImplementedError("%s not supported" % key)
+            if "Connection" not in self.request.headers:
+                self.request.headers["Connection"] = "close"
+            if "Host" not in self.request.headers:
+                if "@" in self.parsed.netloc:
+                    self.request.headers["Host"] = self.parsed.netloc.rpartition("@")[
+                        -1
+                    ]
+                else:
+                    self.request.headers["Host"] = self.parsed.netloc
+            username, password = None, None
+            if self.parsed.username is not None:
+                username, password = self.parsed.username, self.parsed.password
+            elif self.request.auth_username is not None:
+                username = self.request.auth_username
+                password = self.request.auth_password or ""
+            if username is not None:
+                assert password is not None
+                if self.request.auth_mode not in (None, "basic"):
+                    raise ValueError("unsupported auth_mode %s", self.request.auth_mode)
+                self.request.headers["Authorization"] = "Basic " + _unicode(
+                    base64.b64encode(
+                        httputil.encode_username_password(username, password)
+                    )
+                )
+            if self.request.user_agent:
+                self.request.headers["User-Agent"] = self.request.user_agent
+            elif self.request.headers.get("User-Agent") is None:
+                self.request.headers["User-Agent"] = "Tornado/{}".format(version)
+            if not self.request.allow_nonstandard_methods:
+                # Some HTTP methods nearly always have bodies while others
+                # almost never do. Fail in this case unless the user has
+                # opted out of sanity checks with allow_nonstandard_methods.
+                body_expected = self.request.method in ("POST", "PATCH", "PUT")
+                body_present = (
+                    self.request.body is not None
+                    or self.request.body_producer is not None
+                )
+                if (body_expected and not body_present) or (
+                    body_present and not body_expected
+                ):
+                    raise ValueError(
+                        "Body must %sbe None for method %s (unless "
+                        "allow_nonstandard_methods is true)"
+                        % ("not " if body_expected else "", self.request.method)
+                    )
+            if self.request.expect_100_continue:
+                self.request.headers["Expect"] = "100-continue"
+            if self.request.body is not None:
+                # When body_producer is used the caller is responsible for
+                # setting Content-Length (or else chunked encoding will be used).
+                self.request.headers["Content-Length"] = str(len(self.request.body))
+            if (
+                self.request.method == "POST"
+                and "Content-Type" not in self.request.headers
+            ):
+                self.request.headers[
+                    "Content-Type"
+                ] = "application/x-www-form-urlencoded"
+            if self.request.decompress_response:
+                self.request.headers["Accept-Encoding"] = "gzip"
+            req_path = (self.parsed.path or "/") + (
+                ("?" + self.parsed.query) if self.parsed.query else ""
+            )
+            self.connection = self._create_connection(stream)
+            start_line = httputil.RequestStartLine(self.request.method, req_path, "")
+            self.connection.write_headers(start_line, self.request.headers)
+            if self.request.expect_100_continue:
+                await self.connection.read_response(self)
+            else:
+                await self._write_body(True)
+        except Exception:
+            if not self._handle_exception(*sys.exc_info()):
+                raise
+
+    def _get_ssl_options(
+        self, scheme: str
+    ) -> Union[None, Dict[str, Any], ssl.SSLContext]:
+        if scheme == "https":
+            if self.request.ssl_options is not None:
+                return self.request.ssl_options
+            # If we are using the defaults, don't construct a
+            # new SSLContext.
+            if (
+                self.request.validate_cert
+                and self.request.ca_certs is None
+                and self.request.client_cert is None
+                and self.request.client_key is None
+            ):
+                return _client_ssl_defaults
+            ssl_ctx = ssl.create_default_context(
+                ssl.Purpose.SERVER_AUTH, cafile=self.request.ca_certs
+            )
+            if not self.request.validate_cert:
+                ssl_ctx.check_hostname = False
+                ssl_ctx.verify_mode = ssl.CERT_NONE
+            if self.request.client_cert is not None:
+                ssl_ctx.load_cert_chain(
+                    self.request.client_cert, self.request.client_key
+                )
+            if hasattr(ssl, "OP_NO_COMPRESSION"):
+                # See netutil.ssl_options_to_context
+                ssl_ctx.options |= ssl.OP_NO_COMPRESSION
+            return ssl_ctx
+        return None
+
+    def _on_timeout(self, info: Optional[str] = None) -> None:
+        """Timeout callback of _HTTPConnection instance.
+
+        Raise a `HTTPTimeoutError` when a timeout occurs.
+
+        :info string key: More detailed timeout information.
+        """
+        self._timeout = None
+        error_message = "Timeout {0}".format(info) if info else "Timeout"
+        if self.final_callback is not None:
+            self._handle_exception(
+                HTTPTimeoutError, HTTPTimeoutError(error_message), None
+            )
+
+    def _remove_timeout(self) -> None:
+        if self._timeout is not None:
+            self.io_loop.remove_timeout(self._timeout)
+            self._timeout = None
+
+    def _create_connection(self, stream: IOStream) -> HTTP1Connection:
+        stream.set_nodelay(True)
+        connection = HTTP1Connection(
+            stream,
+            True,
+            HTTP1ConnectionParameters(
+                no_keep_alive=True,
+                max_header_size=self.max_header_size,
+                max_body_size=self.max_body_size,
+                decompress=bool(self.request.decompress_response),
+            ),
+            self._sockaddr,
+        )
+        return connection
+
+    async def _write_body(self, start_read: bool) -> None:
+        if self.request.body is not None:
+            self.connection.write(self.request.body)
+        elif self.request.body_producer is not None:
+            fut = self.request.body_producer(self.connection.write)
+            if fut is not None:
+                await fut
+        self.connection.finish()
+        if start_read:
+            try:
+                await self.connection.read_response(self)
+            except StreamClosedError:
+                if not self._handle_exception(*sys.exc_info()):
+                    raise
+
+    def _release(self) -> None:
+        if self.release_callback is not None:
+            release_callback = self.release_callback
+            self.release_callback = None  # type: ignore
+            release_callback()
+
+    def _run_callback(self, response: HTTPResponse) -> None:
+        self._release()
+        if self.final_callback is not None:
+            final_callback = self.final_callback
+            self.final_callback = None  # type: ignore
+            self.io_loop.add_callback(final_callback, response)
+
+    def _handle_exception(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[TracebackType],
+    ) -> bool:
+        if self.final_callback is not None:
+            self._remove_timeout()
+            if isinstance(value, StreamClosedError):
+                if value.real_error is None:
+                    value = HTTPStreamClosedError("Stream closed")
+                else:
+                    value = value.real_error
+            self._run_callback(
+                HTTPResponse(
+                    self.request,
+                    599,
+                    error=value,
+                    request_time=self.io_loop.time() - self.start_time,
+                    start_time=self.start_wall_time,
+                )
+            )
+
+            if hasattr(self, "stream"):
+                # TODO: this may cause a StreamClosedError to be raised
+                # by the connection's Future.  Should we cancel the
+                # connection more gracefully?
+                self.stream.close()
+            return True
+        else:
+            # If our callback has already been called, we are probably
+            # catching an exception that is not caused by us but rather
+            # some child of our callback. Rather than drop it on the floor,
+            # pass it along, unless it's just the stream being closed.
+            return isinstance(value, StreamClosedError)
+
+    def on_connection_close(self) -> None:
+        if self.final_callback is not None:
+            message = "Connection closed"
+            if self.stream.error:
+                raise self.stream.error
+            try:
+                raise HTTPStreamClosedError(message)
+            except HTTPStreamClosedError:
+                self._handle_exception(*sys.exc_info())
+
+    async def headers_received(
+        self,
+        first_line: Union[httputil.ResponseStartLine, httputil.RequestStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> None:
+        assert isinstance(first_line, httputil.ResponseStartLine)
+        if self.request.expect_100_continue and first_line.code == 100:
+            await self._write_body(False)
+            return
+        self.code = first_line.code
+        self.reason = first_line.reason
+        self.headers = headers
+
+        if self._should_follow_redirect():
+            return
+
+        if self.request.header_callback is not None:
+            # Reassemble the start line.
+            self.request.header_callback("%s %s %s\r\n" % first_line)
+            for k, v in self.headers.get_all():
+                self.request.header_callback("%s: %s\r\n" % (k, v))
+            self.request.header_callback("\r\n")
+
+    def _should_follow_redirect(self) -> bool:
+        if self.request.follow_redirects:
+            assert self.request.max_redirects is not None
+            return (
+                self.code in (301, 302, 303, 307, 308)
+                and self.request.max_redirects > 0
+                and self.headers is not None
+                and self.headers.get("Location") is not None
+            )
+        return False
+
+    def finish(self) -> None:
+        assert self.code is not None
+        data = b"".join(self.chunks)
+        self._remove_timeout()
+        original_request = getattr(self.request, "original_request", self.request)
+        if self._should_follow_redirect():
+            assert isinstance(self.request, _RequestProxy)
+            assert self.headers is not None
+            new_request = copy.copy(self.request.request)
+            new_request.url = urllib.parse.urljoin(
+                self.request.url, self.headers["Location"]
+            )
+            assert self.request.max_redirects is not None
+            new_request.max_redirects = self.request.max_redirects - 1
+            del new_request.headers["Host"]
+            # https://tools.ietf.org/html/rfc7231#section-6.4
+            #
+            # The original HTTP spec said that after a 301 or 302
+            # redirect, the request method should be preserved.
+            # However, browsers implemented this by changing the
+            # method to GET, and the behavior stuck. 303 redirects
+            # always specified this POST-to-GET behavior, arguably
+            # for *all* methods, but libcurl < 7.70 only does this
+            # for POST, while libcurl >= 7.70 does it for other methods.
+            if (self.code == 303 and self.request.method != "HEAD") or (
+                self.code in (301, 302) and self.request.method == "POST"
+            ):
+                new_request.method = "GET"
+                new_request.body = None  # type: ignore
+                for h in [
+                    "Content-Length",
+                    "Content-Type",
+                    "Content-Encoding",
+                    "Transfer-Encoding",
+                ]:
+                    try:
+                        del self.request.headers[h]
+                    except KeyError:
+                        pass
+            new_request.original_request = original_request  # type: ignore
+            final_callback = self.final_callback
+            self.final_callback = None  # type: ignore
+            self._release()
+            assert self.client is not None
+            fut = self.client.fetch(new_request, raise_error=False)
+            fut.add_done_callback(lambda f: final_callback(f.result()))
+            self._on_end_request()
+            return
+        if self.request.streaming_callback:
+            buffer = BytesIO()
+        else:
+            buffer = BytesIO(data)  # TODO: don't require one big string?
+        response = HTTPResponse(
+            original_request,
+            self.code,
+            reason=getattr(self, "reason", None),
+            headers=self.headers,
+            request_time=self.io_loop.time() - self.start_time,
+            start_time=self.start_wall_time,
+            buffer=buffer,
+            effective_url=self.request.url,
+        )
+        self._run_callback(response)
+        self._on_end_request()
+
+    def _on_end_request(self) -> None:
+        self.stream.close()
+
+    def data_received(self, chunk: bytes) -> None:
+        if self._should_follow_redirect():
+            # We're going to follow a redirect so just discard the body.
+            return
+        if self.request.streaming_callback is not None:
+            self.request.streaming_callback(chunk)
+        else:
+            self.chunks.append(chunk)
+
+
+if __name__ == "__main__":
+    AsyncHTTPClient.configure(SimpleAsyncHTTPClient)
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/speedups.abi3.so b/venv/lib/python3.9/site-packages/tornado/speedups.abi3.so
new file mode 100755
index 00000000..8ef95904
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/speedups.abi3.so
diff --git a/venv/lib/python3.9/site-packages/tornado/tcpclient.py b/venv/lib/python3.9/site-packages/tornado/tcpclient.py
new file mode 100644
index 00000000..0a829062
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/tcpclient.py
@@ -0,0 +1,332 @@
+#
+# Copyright 2014 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""A non-blocking TCP connection factory.
+"""
+
+import functools
+import socket
+import numbers
+import datetime
+import ssl
+import typing
+
+from tornado.concurrent import Future, future_add_done_callback
+from tornado.ioloop import IOLoop
+from tornado.iostream import IOStream
+from tornado import gen
+from tornado.netutil import Resolver
+from tornado.gen import TimeoutError
+
+from typing import Any, Union, Dict, Tuple, List, Callable, Iterator, Optional
+
+if typing.TYPE_CHECKING:
+    from typing import Set  # noqa(F401)
+
+_INITIAL_CONNECT_TIMEOUT = 0.3
+
+
+class _Connector(object):
+    """A stateless implementation of the "Happy Eyeballs" algorithm.
+
+    "Happy Eyeballs" is documented in RFC6555 as the recommended practice
+    for when both IPv4 and IPv6 addresses are available.
+
+    In this implementation, we partition the addresses by family, and
+    make the first connection attempt to whichever address was
+    returned first by ``getaddrinfo``.  If that connection fails or
+    times out, we begin a connection in parallel to the first address
+    of the other family.  If there are additional failures we retry
+    with other addresses, keeping one connection attempt per family
+    in flight at a time.
+
+    http://tools.ietf.org/html/rfc6555
+
+    """
+
+    def __init__(
+        self,
+        addrinfo: List[Tuple],
+        connect: Callable[
+            [socket.AddressFamily, Tuple], Tuple[IOStream, "Future[IOStream]"]
+        ],
+    ) -> None:
+        self.io_loop = IOLoop.current()
+        self.connect = connect
+
+        self.future = (
+            Future()
+        )  # type: Future[Tuple[socket.AddressFamily, Any, IOStream]]
+        self.timeout = None  # type: Optional[object]
+        self.connect_timeout = None  # type: Optional[object]
+        self.last_error = None  # type: Optional[Exception]
+        self.remaining = len(addrinfo)
+        self.primary_addrs, self.secondary_addrs = self.split(addrinfo)
+        self.streams = set()  # type: Set[IOStream]
+
+    @staticmethod
+    def split(
+        addrinfo: List[Tuple],
+    ) -> Tuple[
+        List[Tuple[socket.AddressFamily, Tuple]],
+        List[Tuple[socket.AddressFamily, Tuple]],
+    ]:
+        """Partition the ``addrinfo`` list by address family.
+
+        Returns two lists.  The first list contains the first entry from
+        ``addrinfo`` and all others with the same family, and the
+        second list contains all other addresses (normally one list will
+        be AF_INET and the other AF_INET6, although non-standard resolvers
+        may return additional families).
+        """
+        primary = []
+        secondary = []
+        primary_af = addrinfo[0][0]
+        for af, addr in addrinfo:
+            if af == primary_af:
+                primary.append((af, addr))
+            else:
+                secondary.append((af, addr))
+        return primary, secondary
+
+    def start(
+        self,
+        timeout: float = _INITIAL_CONNECT_TIMEOUT,
+        connect_timeout: Optional[Union[float, datetime.timedelta]] = None,
+    ) -> "Future[Tuple[socket.AddressFamily, Any, IOStream]]":
+        self.try_connect(iter(self.primary_addrs))
+        self.set_timeout(timeout)
+        if connect_timeout is not None:
+            self.set_connect_timeout(connect_timeout)
+        return self.future
+
+    def try_connect(self, addrs: Iterator[Tuple[socket.AddressFamily, Tuple]]) -> None:
+        try:
+            af, addr = next(addrs)
+        except StopIteration:
+            # We've reached the end of our queue, but the other queue
+            # might still be working.  Send a final error on the future
+            # only when both queues are finished.
+            if self.remaining == 0 and not self.future.done():
+                self.future.set_exception(
+                    self.last_error or IOError("connection failed")
+                )
+            return
+        stream, future = self.connect(af, addr)
+        self.streams.add(stream)
+        future_add_done_callback(
+            future, functools.partial(self.on_connect_done, addrs, af, addr)
+        )
+
+    def on_connect_done(
+        self,
+        addrs: Iterator[Tuple[socket.AddressFamily, Tuple]],
+        af: socket.AddressFamily,
+        addr: Tuple,
+        future: "Future[IOStream]",
+    ) -> None:
+        self.remaining -= 1
+        try:
+            stream = future.result()
+        except Exception as e:
+            if self.future.done():
+                return
+            # Error: try again (but remember what happened so we have an
+            # error to raise in the end)
+            self.last_error = e
+            self.try_connect(addrs)
+            if self.timeout is not None:
+                # If the first attempt failed, don't wait for the
+                # timeout to try an address from the secondary queue.
+                self.io_loop.remove_timeout(self.timeout)
+                self.on_timeout()
+            return
+        self.clear_timeouts()
+        if self.future.done():
+            # This is a late arrival; just drop it.
+            stream.close()
+        else:
+            self.streams.discard(stream)
+            self.future.set_result((af, addr, stream))
+            self.close_streams()
+
+    def set_timeout(self, timeout: float) -> None:
+        self.timeout = self.io_loop.add_timeout(
+            self.io_loop.time() + timeout, self.on_timeout
+        )
+
+    def on_timeout(self) -> None:
+        self.timeout = None
+        if not self.future.done():
+            self.try_connect(iter(self.secondary_addrs))
+
+    def clear_timeout(self) -> None:
+        if self.timeout is not None:
+            self.io_loop.remove_timeout(self.timeout)
+
+    def set_connect_timeout(
+        self, connect_timeout: Union[float, datetime.timedelta]
+    ) -> None:
+        self.connect_timeout = self.io_loop.add_timeout(
+            connect_timeout, self.on_connect_timeout
+        )
+
+    def on_connect_timeout(self) -> None:
+        if not self.future.done():
+            self.future.set_exception(TimeoutError())
+        self.close_streams()
+
+    def clear_timeouts(self) -> None:
+        if self.timeout is not None:
+            self.io_loop.remove_timeout(self.timeout)
+        if self.connect_timeout is not None:
+            self.io_loop.remove_timeout(self.connect_timeout)
+
+    def close_streams(self) -> None:
+        for stream in self.streams:
+            stream.close()
+
+
+class TCPClient(object):
+    """A non-blocking TCP connection factory.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+    """
+
+    def __init__(self, resolver: Optional[Resolver] = None) -> None:
+        if resolver is not None:
+            self.resolver = resolver
+            self._own_resolver = False
+        else:
+            self.resolver = Resolver()
+            self._own_resolver = True
+
+    def close(self) -> None:
+        if self._own_resolver:
+            self.resolver.close()
+
+    async def connect(
+        self,
+        host: str,
+        port: int,
+        af: socket.AddressFamily = socket.AF_UNSPEC,
+        ssl_options: Optional[Union[Dict[str, Any], ssl.SSLContext]] = None,
+        max_buffer_size: Optional[int] = None,
+        source_ip: Optional[str] = None,
+        source_port: Optional[int] = None,
+        timeout: Optional[Union[float, datetime.timedelta]] = None,
+    ) -> IOStream:
+        """Connect to the given host and port.
+
+        Asynchronously returns an `.IOStream` (or `.SSLIOStream` if
+        ``ssl_options`` is not None).
+
+        Using the ``source_ip`` kwarg, one can specify the source
+        IP address to use when establishing the connection.
+        In case the user needs to resolve and
+        use a specific interface, it has to be handled outside
+        of Tornado as this depends very much on the platform.
+
+        Raises `TimeoutError` if the input future does not complete before
+        ``timeout``, which may be specified in any form allowed by
+        `.IOLoop.add_timeout` (i.e. a `datetime.timedelta` or an absolute time
+        relative to `.IOLoop.time`)
+
+        Similarly, when the user requires a certain source port, it can
+        be specified using the ``source_port`` arg.
+
+        .. versionchanged:: 4.5
+           Added the ``source_ip`` and ``source_port`` arguments.
+
+        .. versionchanged:: 5.0
+           Added the ``timeout`` argument.
+        """
+        if timeout is not None:
+            if isinstance(timeout, numbers.Real):
+                timeout = IOLoop.current().time() + timeout
+            elif isinstance(timeout, datetime.timedelta):
+                timeout = IOLoop.current().time() + timeout.total_seconds()
+            else:
+                raise TypeError("Unsupported timeout %r" % timeout)
+        if timeout is not None:
+            addrinfo = await gen.with_timeout(
+                timeout, self.resolver.resolve(host, port, af)
+            )
+        else:
+            addrinfo = await self.resolver.resolve(host, port, af)
+        connector = _Connector(
+            addrinfo,
+            functools.partial(
+                self._create_stream,
+                max_buffer_size,
+                source_ip=source_ip,
+                source_port=source_port,
+            ),
+        )
+        af, addr, stream = await connector.start(connect_timeout=timeout)
+        # TODO: For better performance we could cache the (af, addr)
+        # information here and re-use it on subsequent connections to
+        # the same host. (http://tools.ietf.org/html/rfc6555#section-4.2)
+        if ssl_options is not None:
+            if timeout is not None:
+                stream = await gen.with_timeout(
+                    timeout,
+                    stream.start_tls(
+                        False, ssl_options=ssl_options, server_hostname=host
+                    ),
+                )
+            else:
+                stream = await stream.start_tls(
+                    False, ssl_options=ssl_options, server_hostname=host
+                )
+        return stream
+
+    def _create_stream(
+        self,
+        max_buffer_size: int,
+        af: socket.AddressFamily,
+        addr: Tuple,
+        source_ip: Optional[str] = None,
+        source_port: Optional[int] = None,
+    ) -> Tuple[IOStream, "Future[IOStream]"]:
+        # Always connect in plaintext; we'll convert to ssl if necessary
+        # after one connection has completed.
+        source_port_bind = source_port if isinstance(source_port, int) else 0
+        source_ip_bind = source_ip
+        if source_port_bind and not source_ip:
+            # User required a specific port, but did not specify
+            # a certain source IP, will bind to the default loopback.
+            source_ip_bind = "::1" if af == socket.AF_INET6 else "127.0.0.1"
+            # Trying to use the same address family as the requested af socket:
+            # - 127.0.0.1 for IPv4
+            # - ::1 for IPv6
+        socket_obj = socket.socket(af)
+        if source_port_bind or source_ip_bind:
+            # If the user requires binding also to a specific IP/port.
+            try:
+                socket_obj.bind((source_ip_bind, source_port_bind))
+            except socket.error:
+                socket_obj.close()
+                # Fail loudly if unable to use the IP/port.
+                raise
+        try:
+            stream = IOStream(socket_obj, max_buffer_size=max_buffer_size)
+        except socket.error as e:
+            fu = Future()  # type: Future[IOStream]
+            fu.set_exception(e)
+            return stream, fu
+        else:
+            return stream, stream.connect(addr)
diff --git a/venv/lib/python3.9/site-packages/tornado/tcpserver.py b/venv/lib/python3.9/site-packages/tornado/tcpserver.py
new file mode 100644
index 00000000..deab8f2a
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/tcpserver.py
@@ -0,0 +1,390 @@
+#
+# Copyright 2011 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""A non-blocking, single-threaded TCP server."""
+
+import errno
+import os
+import socket
+import ssl
+
+from tornado import gen
+from tornado.log import app_log
+from tornado.ioloop import IOLoop
+from tornado.iostream import IOStream, SSLIOStream
+from tornado.netutil import (
+    bind_sockets,
+    add_accept_handler,
+    ssl_wrap_socket,
+    _DEFAULT_BACKLOG,
+)
+from tornado import process
+from tornado.util import errno_from_exception
+
+import typing
+from typing import Union, Dict, Any, Iterable, Optional, Awaitable
+
+if typing.TYPE_CHECKING:
+    from typing import Callable, List  # noqa: F401
+
+
+class TCPServer(object):
+    r"""A non-blocking, single-threaded TCP server.
+
+    To use `TCPServer`, define a subclass which overrides the `handle_stream`
+    method. For example, a simple echo server could be defined like this::
+
+      from tornado.tcpserver import TCPServer
+      from tornado.iostream import StreamClosedError
+
+      class EchoServer(TCPServer):
+          async def handle_stream(self, stream, address):
+              while True:
+                  try:
+                      data = await stream.read_until(b"\n") await
+                      stream.write(data)
+                  except StreamClosedError:
+                      break
+
+    To make this server serve SSL traffic, send the ``ssl_options`` keyword
+    argument with an `ssl.SSLContext` object. For compatibility with older
+    versions of Python ``ssl_options`` may also be a dictionary of keyword
+    arguments for the `ssl.wrap_socket` method.::
+
+       ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+       ssl_ctx.load_cert_chain(os.path.join(data_dir, "mydomain.crt"),
+                               os.path.join(data_dir, "mydomain.key"))
+       TCPServer(ssl_options=ssl_ctx)
+
+    `TCPServer` initialization follows one of three patterns:
+
+    1. `listen`: single-process::
+
+            async def main():
+                server = TCPServer()
+                server.listen(8888)
+                await asyncio.Event.wait()
+
+            asyncio.run(main())
+
+       While this example does not create multiple processes on its own, when
+       the ``reuse_port=True`` argument is passed to ``listen()`` you can run
+       the program multiple times to create a multi-process service.
+
+    2. `add_sockets`: multi-process::
+
+            sockets = bind_sockets(8888)
+            tornado.process.fork_processes(0)
+            async def post_fork_main():
+                server = TCPServer()
+                server.add_sockets(sockets)
+                await asyncio.Event().wait()
+            asyncio.run(post_fork_main())
+
+       The `add_sockets` interface is more complicated, but it can be used with
+       `tornado.process.fork_processes` to run a multi-process service with all
+       worker processes forked from a single parent.  `add_sockets` can also be
+       used in single-process servers if you want to create your listening
+       sockets in some way other than `~tornado.netutil.bind_sockets`.
+
+       Note that when using this pattern, nothing that touches the event loop
+       can be run before ``fork_processes``.
+
+    3. `bind`/`start`: simple **deprecated** multi-process::
+
+            server = TCPServer()
+            server.bind(8888)
+            server.start(0)  # Forks multiple sub-processes
+            IOLoop.current().start()
+
+       This pattern is deprecated because it requires interfaces in the
+       `asyncio` module that have been deprecated since Python 3.10. Support for
+       creating multiple processes in the ``start`` method will be removed in a
+       future version of Tornado.
+
+    .. versionadded:: 3.1
+       The ``max_buffer_size`` argument.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument has been removed.
+    """
+
+    def __init__(
+        self,
+        ssl_options: Optional[Union[Dict[str, Any], ssl.SSLContext]] = None,
+        max_buffer_size: Optional[int] = None,
+        read_chunk_size: Optional[int] = None,
+    ) -> None:
+        self.ssl_options = ssl_options
+        self._sockets = {}  # type: Dict[int, socket.socket]
+        self._handlers = {}  # type: Dict[int, Callable[[], None]]
+        self._pending_sockets = []  # type: List[socket.socket]
+        self._started = False
+        self._stopped = False
+        self.max_buffer_size = max_buffer_size
+        self.read_chunk_size = read_chunk_size
+
+        # Verify the SSL options. Otherwise we don't get errors until clients
+        # connect. This doesn't verify that the keys are legitimate, but
+        # the SSL module doesn't do that until there is a connected socket
+        # which seems like too much work
+        if self.ssl_options is not None and isinstance(self.ssl_options, dict):
+            # Only certfile is required: it can contain both keys
+            if "certfile" not in self.ssl_options:
+                raise KeyError('missing key "certfile" in ssl_options')
+
+            if not os.path.exists(self.ssl_options["certfile"]):
+                raise ValueError(
+                    'certfile "%s" does not exist' % self.ssl_options["certfile"]
+                )
+            if "keyfile" in self.ssl_options and not os.path.exists(
+                self.ssl_options["keyfile"]
+            ):
+                raise ValueError(
+                    'keyfile "%s" does not exist' % self.ssl_options["keyfile"]
+                )
+
+    def listen(
+        self,
+        port: int,
+        address: Optional[str] = None,
+        family: socket.AddressFamily = socket.AF_UNSPEC,
+        backlog: int = _DEFAULT_BACKLOG,
+        flags: Optional[int] = None,
+        reuse_port: bool = False,
+    ) -> None:
+        """Starts accepting connections on the given port.
+
+        This method may be called more than once to listen on multiple ports.
+        `listen` takes effect immediately; it is not necessary to call
+        `TCPServer.start` afterwards.  It is, however, necessary to start the
+        event loop if it is not already running.
+
+        All arguments have the same meaning as in
+        `tornado.netutil.bind_sockets`.
+
+        .. versionchanged:: 6.2
+
+           Added ``family``, ``backlog``, ``flags``, and ``reuse_port``
+           arguments to match `tornado.netutil.bind_sockets`.
+        """
+        sockets = bind_sockets(
+            port,
+            address=address,
+            family=family,
+            backlog=backlog,
+            flags=flags,
+            reuse_port=reuse_port,
+        )
+        self.add_sockets(sockets)
+
+    def add_sockets(self, sockets: Iterable[socket.socket]) -> None:
+        """Makes this server start accepting connections on the given sockets.
+
+        The ``sockets`` parameter is a list of socket objects such as
+        those returned by `~tornado.netutil.bind_sockets`.
+        `add_sockets` is typically used in combination with that
+        method and `tornado.process.fork_processes` to provide greater
+        control over the initialization of a multi-process server.
+        """
+        for sock in sockets:
+            self._sockets[sock.fileno()] = sock
+            self._handlers[sock.fileno()] = add_accept_handler(
+                sock, self._handle_connection
+            )
+
+    def add_socket(self, socket: socket.socket) -> None:
+        """Singular version of `add_sockets`.  Takes a single socket object."""
+        self.add_sockets([socket])
+
+    def bind(
+        self,
+        port: int,
+        address: Optional[str] = None,
+        family: socket.AddressFamily = socket.AF_UNSPEC,
+        backlog: int = _DEFAULT_BACKLOG,
+        flags: Optional[int] = None,
+        reuse_port: bool = False,
+    ) -> None:
+        """Binds this server to the given port on the given address.
+
+        To start the server, call `start`. If you want to run this server in a
+        single process, you can call `listen` as a shortcut to the sequence of
+        `bind` and `start` calls.
+
+        Address may be either an IP address or hostname.  If it's a hostname,
+        the server will listen on all IP addresses associated with the name.
+        Address may be an empty string or None to listen on all available
+        interfaces.  Family may be set to either `socket.AF_INET` or
+        `socket.AF_INET6` to restrict to IPv4 or IPv6 addresses, otherwise both
+        will be used if available.
+
+        The ``backlog`` argument has the same meaning as for `socket.listen
+        <socket.socket.listen>`. The ``reuse_port`` argument has the same
+        meaning as for `.bind_sockets`.
+
+        This method may be called multiple times prior to `start` to listen on
+        multiple ports or interfaces.
+
+        .. versionchanged:: 4.4
+           Added the ``reuse_port`` argument.
+
+        .. versionchanged:: 6.2
+           Added the ``flags`` argument to match `.bind_sockets`.
+
+        .. deprecated:: 6.2
+           Use either ``listen()`` or ``add_sockets()`` instead of ``bind()``
+           and ``start()``.
+        """
+        sockets = bind_sockets(
+            port,
+            address=address,
+            family=family,
+            backlog=backlog,
+            flags=flags,
+            reuse_port=reuse_port,
+        )
+        if self._started:
+            self.add_sockets(sockets)
+        else:
+            self._pending_sockets.extend(sockets)
+
+    def start(
+        self, num_processes: Optional[int] = 1, max_restarts: Optional[int] = None
+    ) -> None:
+        """Starts this server in the `.IOLoop`.
+
+        By default, we run the server in this process and do not fork any
+        additional child process.
+
+        If num_processes is ``None`` or <= 0, we detect the number of cores
+        available on this machine and fork that number of child
+        processes. If num_processes is given and > 1, we fork that
+        specific number of sub-processes.
+
+        Since we use processes and not threads, there is no shared memory
+        between any server code.
+
+        Note that multiple processes are not compatible with the autoreload
+        module (or the ``autoreload=True`` option to `tornado.web.Application`
+        which defaults to True when ``debug=True``).
+        When using multiple processes, no IOLoops can be created or
+        referenced until after the call to ``TCPServer.start(n)``.
+
+        Values of ``num_processes`` other than 1 are not supported on Windows.
+
+        The ``max_restarts`` argument is passed to `.fork_processes`.
+
+        .. versionchanged:: 6.0
+
+           Added ``max_restarts`` argument.
+
+        .. deprecated:: 6.2
+           Use either ``listen()`` or ``add_sockets()`` instead of ``bind()``
+           and ``start()``.
+        """
+        assert not self._started
+        self._started = True
+        if num_processes != 1:
+            process.fork_processes(num_processes, max_restarts)
+        sockets = self._pending_sockets
+        self._pending_sockets = []
+        self.add_sockets(sockets)
+
+    def stop(self) -> None:
+        """Stops listening for new connections.
+
+        Requests currently in progress may still continue after the
+        server is stopped.
+        """
+        if self._stopped:
+            return
+        self._stopped = True
+        for fd, sock in self._sockets.items():
+            assert sock.fileno() == fd
+            # Unregister socket from IOLoop
+            self._handlers.pop(fd)()
+            sock.close()
+
+    def handle_stream(
+        self, stream: IOStream, address: tuple
+    ) -> Optional[Awaitable[None]]:
+        """Override to handle a new `.IOStream` from an incoming connection.
+
+        This method may be a coroutine; if so any exceptions it raises
+        asynchronously will be logged. Accepting of incoming connections
+        will not be blocked by this coroutine.
+
+        If this `TCPServer` is configured for SSL, ``handle_stream``
+        may be called before the SSL handshake has completed. Use
+        `.SSLIOStream.wait_for_handshake` if you need to verify the client's
+        certificate or use NPN/ALPN.
+
+        .. versionchanged:: 4.2
+           Added the option for this method to be a coroutine.
+        """
+        raise NotImplementedError()
+
+    def _handle_connection(self, connection: socket.socket, address: Any) -> None:
+        if self.ssl_options is not None:
+            assert ssl, "Python 2.6+ and OpenSSL required for SSL"
+            try:
+                connection = ssl_wrap_socket(
+                    connection,
+                    self.ssl_options,
+                    server_side=True,
+                    do_handshake_on_connect=False,
+                )
+            except ssl.SSLError as err:
+                if err.args[0] == ssl.SSL_ERROR_EOF:
+                    return connection.close()
+                else:
+                    raise
+            except socket.error as err:
+                # If the connection is closed immediately after it is created
+                # (as in a port scan), we can get one of several errors.
+                # wrap_socket makes an internal call to getpeername,
+                # which may return either EINVAL (Mac OS X) or ENOTCONN
+                # (Linux).  If it returns ENOTCONN, this error is
+                # silently swallowed by the ssl module, so we need to
+                # catch another error later on (AttributeError in
+                # SSLIOStream._do_ssl_handshake).
+                # To test this behavior, try nmap with the -sT flag.
+                # https://github.com/tornadoweb/tornado/pull/750
+                if errno_from_exception(err) in (errno.ECONNABORTED, errno.EINVAL):
+                    return connection.close()
+                else:
+                    raise
+        try:
+            if self.ssl_options is not None:
+                stream = SSLIOStream(
+                    connection,
+                    max_buffer_size=self.max_buffer_size,
+                    read_chunk_size=self.read_chunk_size,
+                )  # type: IOStream
+            else:
+                stream = IOStream(
+                    connection,
+                    max_buffer_size=self.max_buffer_size,
+                    read_chunk_size=self.read_chunk_size,
+                )
+
+            future = self.handle_stream(stream, address)
+            if future is not None:
+                IOLoop.current().add_future(
+                    gen.convert_yielded(future), lambda f: f.result()
+                )
+        except Exception:
+            app_log.error("Error in connection callback", exc_info=True)
diff --git a/venv/lib/python3.9/site-packages/tornado/template.py b/venv/lib/python3.9/site-packages/tornado/template.py
new file mode 100644
index 00000000..d53e977c
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/template.py
@@ -0,0 +1,1047 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""A simple template system that compiles templates to Python code.
+
+Basic usage looks like::
+
+    t = template.Template("<html>{{ myvalue }}</html>")
+    print(t.generate(myvalue="XXX"))
+
+`Loader` is a class that loads templates from a root directory and caches
+the compiled templates::
+
+    loader = template.Loader("/home/btaylor")
+    print(loader.load("test.html").generate(myvalue="XXX"))
+
+We compile all templates to raw Python. Error-reporting is currently... uh,
+interesting. Syntax for the templates::
+
+    ### base.html
+    <html>
+      <head>
+        <title>{% block title %}Default title{% end %}</title>
+      </head>
+      <body>
+        <ul>
+          {% for student in students %}
+            {% block student %}
+              <li>{{ escape(student.name) }}</li>
+            {% end %}
+          {% end %}
+        </ul>
+      </body>
+    </html>
+
+    ### bold.html
+    {% extends "base.html" %}
+
+    {% block title %}A bolder title{% end %}
+
+    {% block student %}
+      <li><span style="bold">{{ escape(student.name) }}</span></li>
+    {% end %}
+
+Unlike most other template systems, we do not put any restrictions on the
+expressions you can include in your statements. ``if`` and ``for`` blocks get
+translated exactly into Python, so you can do complex expressions like::
+
+   {% for student in [p for p in people if p.student and p.age > 23] %}
+     <li>{{ escape(student.name) }}</li>
+   {% end %}
+
+Translating directly to Python means you can apply functions to expressions
+easily, like the ``escape()`` function in the examples above. You can pass
+functions in to your template just like any other variable
+(In a `.RequestHandler`, override `.RequestHandler.get_template_namespace`)::
+
+   ### Python code
+   def add(x, y):
+      return x + y
+   template.execute(add=add)
+
+   ### The template
+   {{ add(1, 2) }}
+
+We provide the functions `escape() <.xhtml_escape>`, `.url_escape()`,
+`.json_encode()`, and `.squeeze()` to all templates by default.
+
+Typical applications do not create `Template` or `Loader` instances by
+hand, but instead use the `~.RequestHandler.render` and
+`~.RequestHandler.render_string` methods of
+`tornado.web.RequestHandler`, which load templates automatically based
+on the ``template_path`` `.Application` setting.
+
+Variable names beginning with ``_tt_`` are reserved by the template
+system and should not be used by application code.
+
+Syntax Reference
+----------------
+
+Template expressions are surrounded by double curly braces: ``{{ ... }}``.
+The contents may be any python expression, which will be escaped according
+to the current autoescape setting and inserted into the output.  Other
+template directives use ``{% %}``.
+
+To comment out a section so that it is omitted from the output, surround it
+with ``{# ... #}``.
+
+
+To include a literal ``{{``, ``{%``, or ``{#`` in the output, escape them as
+``{{!``, ``{%!``, and ``{#!``, respectively.
+
+
+``{% apply *function* %}...{% end %}``
+    Applies a function to the output of all template code between ``apply``
+    and ``end``::
+
+        {% apply linkify %}{{name}} said: {{message}}{% end %}
+
+    Note that as an implementation detail apply blocks are implemented
+    as nested functions and thus may interact strangely with variables
+    set via ``{% set %}``, or the use of ``{% break %}`` or ``{% continue %}``
+    within loops.
+
+``{% autoescape *function* %}``
+    Sets the autoescape mode for the current file.  This does not affect
+    other files, even those referenced by ``{% include %}``.  Note that
+    autoescaping can also be configured globally, at the `.Application`
+    or `Loader`.::
+
+        {% autoescape xhtml_escape %}
+        {% autoescape None %}
+
+``{% block *name* %}...{% end %}``
+    Indicates a named, replaceable block for use with ``{% extends %}``.
+    Blocks in the parent template will be replaced with the contents of
+    the same-named block in a child template.::
+
+        <!-- base.html -->
+        <title>{% block title %}Default title{% end %}</title>
+
+        <!-- mypage.html -->
+        {% extends "base.html" %}
+        {% block title %}My page title{% end %}
+
+``{% comment ... %}``
+    A comment which will be removed from the template output.  Note that
+    there is no ``{% end %}`` tag; the comment goes from the word ``comment``
+    to the closing ``%}`` tag.
+
+``{% extends *filename* %}``
+    Inherit from another template.  Templates that use ``extends`` should
+    contain one or more ``block`` tags to replace content from the parent
+    template.  Anything in the child template not contained in a ``block``
+    tag will be ignored.  For an example, see the ``{% block %}`` tag.
+
+``{% for *var* in *expr* %}...{% end %}``
+    Same as the python ``for`` statement.  ``{% break %}`` and
+    ``{% continue %}`` may be used inside the loop.
+
+``{% from *x* import *y* %}``
+    Same as the python ``import`` statement.
+
+``{% if *condition* %}...{% elif *condition* %}...{% else %}...{% end %}``
+    Conditional statement - outputs the first section whose condition is
+    true.  (The ``elif`` and ``else`` sections are optional)
+
+``{% import *module* %}``
+    Same as the python ``import`` statement.
+
+``{% include *filename* %}``
+    Includes another template file.  The included file can see all the local
+    variables as if it were copied directly to the point of the ``include``
+    directive (the ``{% autoescape %}`` directive is an exception).
+    Alternately, ``{% module Template(filename, **kwargs) %}`` may be used
+    to include another template with an isolated namespace.
+
+``{% module *expr* %}``
+    Renders a `~tornado.web.UIModule`.  The output of the ``UIModule`` is
+    not escaped::
+
+        {% module Template("foo.html", arg=42) %}
+
+    ``UIModules`` are a feature of the `tornado.web.RequestHandler`
+    class (and specifically its ``render`` method) and will not work
+    when the template system is used on its own in other contexts.
+
+``{% raw *expr* %}``
+    Outputs the result of the given expression without autoescaping.
+
+``{% set *x* = *y* %}``
+    Sets a local variable.
+
+``{% try %}...{% except %}...{% else %}...{% finally %}...{% end %}``
+    Same as the python ``try`` statement.
+
+``{% while *condition* %}... {% end %}``
+    Same as the python ``while`` statement.  ``{% break %}`` and
+    ``{% continue %}`` may be used inside the loop.
+
+``{% whitespace *mode* %}``
+    Sets the whitespace mode for the remainder of the current file
+    (or until the next ``{% whitespace %}`` directive). See
+    `filter_whitespace` for available options. New in Tornado 4.3.
+"""
+
+import datetime
+from io import StringIO
+import linecache
+import os.path
+import posixpath
+import re
+import threading
+
+from tornado import escape
+from tornado.log import app_log
+from tornado.util import ObjectDict, exec_in, unicode_type
+
+from typing import Any, Union, Callable, List, Dict, Iterable, Optional, TextIO
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Tuple, ContextManager  # noqa: F401
+
+_DEFAULT_AUTOESCAPE = "xhtml_escape"
+
+
+class _UnsetMarker:
+    pass
+
+
+_UNSET = _UnsetMarker()
+
+
+def filter_whitespace(mode: str, text: str) -> str:
+    """Transform whitespace in ``text`` according to ``mode``.
+
+    Available modes are:
+
+    * ``all``: Return all whitespace unmodified.
+    * ``single``: Collapse consecutive whitespace with a single whitespace
+      character, preserving newlines.
+    * ``oneline``: Collapse all runs of whitespace into a single space
+      character, removing all newlines in the process.
+
+    .. versionadded:: 4.3
+    """
+    if mode == "all":
+        return text
+    elif mode == "single":
+        text = re.sub(r"([\t ]+)", " ", text)
+        text = re.sub(r"(\s*\n\s*)", "\n", text)
+        return text
+    elif mode == "oneline":
+        return re.sub(r"(\s+)", " ", text)
+    else:
+        raise Exception("invalid whitespace mode %s" % mode)
+
+
+class Template(object):
+    """A compiled template.
+
+    We compile into Python from the given template_string. You can generate
+    the template from variables with generate().
+    """
+
+    # note that the constructor's signature is not extracted with
+    # autodoc because _UNSET looks like garbage.  When changing
+    # this signature update website/sphinx/template.rst too.
+    def __init__(
+        self,
+        template_string: Union[str, bytes],
+        name: str = "<string>",
+        loader: Optional["BaseLoader"] = None,
+        compress_whitespace: Union[bool, _UnsetMarker] = _UNSET,
+        autoescape: Optional[Union[str, _UnsetMarker]] = _UNSET,
+        whitespace: Optional[str] = None,
+    ) -> None:
+        """Construct a Template.
+
+        :arg str template_string: the contents of the template file.
+        :arg str name: the filename from which the template was loaded
+            (used for error message).
+        :arg tornado.template.BaseLoader loader: the `~tornado.template.BaseLoader` responsible
+            for this template, used to resolve ``{% include %}`` and ``{% extend %}`` directives.
+        :arg bool compress_whitespace: Deprecated since Tornado 4.3.
+            Equivalent to ``whitespace="single"`` if true and
+            ``whitespace="all"`` if false.
+        :arg str autoescape: The name of a function in the template
+            namespace, or ``None`` to disable escaping by default.
+        :arg str whitespace: A string specifying treatment of whitespace;
+            see `filter_whitespace` for options.
+
+        .. versionchanged:: 4.3
+           Added ``whitespace`` parameter; deprecated ``compress_whitespace``.
+        """
+        self.name = escape.native_str(name)
+
+        if compress_whitespace is not _UNSET:
+            # Convert deprecated compress_whitespace (bool) to whitespace (str).
+            if whitespace is not None:
+                raise Exception("cannot set both whitespace and compress_whitespace")
+            whitespace = "single" if compress_whitespace else "all"
+        if whitespace is None:
+            if loader and loader.whitespace:
+                whitespace = loader.whitespace
+            else:
+                # Whitespace defaults by filename.
+                if name.endswith(".html") or name.endswith(".js"):
+                    whitespace = "single"
+                else:
+                    whitespace = "all"
+        # Validate the whitespace setting.
+        assert whitespace is not None
+        filter_whitespace(whitespace, "")
+
+        if not isinstance(autoescape, _UnsetMarker):
+            self.autoescape = autoescape  # type: Optional[str]
+        elif loader:
+            self.autoescape = loader.autoescape
+        else:
+            self.autoescape = _DEFAULT_AUTOESCAPE
+
+        self.namespace = loader.namespace if loader else {}
+        reader = _TemplateReader(name, escape.native_str(template_string), whitespace)
+        self.file = _File(self, _parse(reader, self))
+        self.code = self._generate_python(loader)
+        self.loader = loader
+        try:
+            # Under python2.5, the fake filename used here must match
+            # the module name used in __name__ below.
+            # The dont_inherit flag prevents template.py's future imports
+            # from being applied to the generated code.
+            self.compiled = compile(
+                escape.to_unicode(self.code),
+                "%s.generated.py" % self.name.replace(".", "_"),
+                "exec",
+                dont_inherit=True,
+            )
+        except Exception:
+            formatted_code = _format_code(self.code).rstrip()
+            app_log.error("%s code:\n%s", self.name, formatted_code)
+            raise
+
+    def generate(self, **kwargs: Any) -> bytes:
+        """Generate this template with the given arguments."""
+        namespace = {
+            "escape": escape.xhtml_escape,
+            "xhtml_escape": escape.xhtml_escape,
+            "url_escape": escape.url_escape,
+            "json_encode": escape.json_encode,
+            "squeeze": escape.squeeze,
+            "linkify": escape.linkify,
+            "datetime": datetime,
+            "_tt_utf8": escape.utf8,  # for internal use
+            "_tt_string_types": (unicode_type, bytes),
+            # __name__ and __loader__ allow the traceback mechanism to find
+            # the generated source code.
+            "__name__": self.name.replace(".", "_"),
+            "__loader__": ObjectDict(get_source=lambda name: self.code),
+        }
+        namespace.update(self.namespace)
+        namespace.update(kwargs)
+        exec_in(self.compiled, namespace)
+        execute = typing.cast(Callable[[], bytes], namespace["_tt_execute"])
+        # Clear the traceback module's cache of source data now that
+        # we've generated a new template (mainly for this module's
+        # unittests, where different tests reuse the same name).
+        linecache.clearcache()
+        return execute()
+
+    def _generate_python(self, loader: Optional["BaseLoader"]) -> str:
+        buffer = StringIO()
+        try:
+            # named_blocks maps from names to _NamedBlock objects
+            named_blocks = {}  # type: Dict[str, _NamedBlock]
+            ancestors = self._get_ancestors(loader)
+            ancestors.reverse()
+            for ancestor in ancestors:
+                ancestor.find_named_blocks(loader, named_blocks)
+            writer = _CodeWriter(buffer, named_blocks, loader, ancestors[0].template)
+            ancestors[0].generate(writer)
+            return buffer.getvalue()
+        finally:
+            buffer.close()
+
+    def _get_ancestors(self, loader: Optional["BaseLoader"]) -> List["_File"]:
+        ancestors = [self.file]
+        for chunk in self.file.body.chunks:
+            if isinstance(chunk, _ExtendsBlock):
+                if not loader:
+                    raise ParseError(
+                        "{% extends %} block found, but no " "template loader"
+                    )
+                template = loader.load(chunk.name, self.name)
+                ancestors.extend(template._get_ancestors(loader))
+        return ancestors
+
+
+class BaseLoader(object):
+    """Base class for template loaders.
+
+    You must use a template loader to use template constructs like
+    ``{% extends %}`` and ``{% include %}``. The loader caches all
+    templates after they are loaded the first time.
+    """
+
+    def __init__(
+        self,
+        autoescape: str = _DEFAULT_AUTOESCAPE,
+        namespace: Optional[Dict[str, Any]] = None,
+        whitespace: Optional[str] = None,
+    ) -> None:
+        """Construct a template loader.
+
+        :arg str autoescape: The name of a function in the template
+            namespace, such as "xhtml_escape", or ``None`` to disable
+            autoescaping by default.
+        :arg dict namespace: A dictionary to be added to the default template
+            namespace, or ``None``.
+        :arg str whitespace: A string specifying default behavior for
+            whitespace in templates; see `filter_whitespace` for options.
+            Default is "single" for files ending in ".html" and ".js" and
+            "all" for other files.
+
+        .. versionchanged:: 4.3
+           Added ``whitespace`` parameter.
+        """
+        self.autoescape = autoescape
+        self.namespace = namespace or {}
+        self.whitespace = whitespace
+        self.templates = {}  # type: Dict[str, Template]
+        # self.lock protects self.templates.  It's a reentrant lock
+        # because templates may load other templates via `include` or
+        # `extends`.  Note that thanks to the GIL this code would be safe
+        # even without the lock, but could lead to wasted work as multiple
+        # threads tried to compile the same template simultaneously.
+        self.lock = threading.RLock()
+
+    def reset(self) -> None:
+        """Resets the cache of compiled templates."""
+        with self.lock:
+            self.templates = {}
+
+    def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
+        """Converts a possibly-relative path to absolute (used internally)."""
+        raise NotImplementedError()
+
+    def load(self, name: str, parent_path: Optional[str] = None) -> Template:
+        """Loads a template."""
+        name = self.resolve_path(name, parent_path=parent_path)
+        with self.lock:
+            if name not in self.templates:
+                self.templates[name] = self._create_template(name)
+            return self.templates[name]
+
+    def _create_template(self, name: str) -> Template:
+        raise NotImplementedError()
+
+
+class Loader(BaseLoader):
+    """A template loader that loads from a single root directory."""
+
+    def __init__(self, root_directory: str, **kwargs: Any) -> None:
+        super().__init__(**kwargs)
+        self.root = os.path.abspath(root_directory)
+
+    def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
+        if (
+            parent_path
+            and not parent_path.startswith("<")
+            and not parent_path.startswith("/")
+            and not name.startswith("/")
+        ):
+            current_path = os.path.join(self.root, parent_path)
+            file_dir = os.path.dirname(os.path.abspath(current_path))
+            relative_path = os.path.abspath(os.path.join(file_dir, name))
+            if relative_path.startswith(self.root):
+                name = relative_path[len(self.root) + 1 :]
+        return name
+
+    def _create_template(self, name: str) -> Template:
+        path = os.path.join(self.root, name)
+        with open(path, "rb") as f:
+            template = Template(f.read(), name=name, loader=self)
+            return template
+
+
+class DictLoader(BaseLoader):
+    """A template loader that loads from a dictionary."""
+
+    def __init__(self, dict: Dict[str, str], **kwargs: Any) -> None:
+        super().__init__(**kwargs)
+        self.dict = dict
+
+    def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:
+        if (
+            parent_path
+            and not parent_path.startswith("<")
+            and not parent_path.startswith("/")
+            and not name.startswith("/")
+        ):
+            file_dir = posixpath.dirname(parent_path)
+            name = posixpath.normpath(posixpath.join(file_dir, name))
+        return name
+
+    def _create_template(self, name: str) -> Template:
+        return Template(self.dict[name], name=name, loader=self)
+
+
+class _Node(object):
+    def each_child(self) -> Iterable["_Node"]:
+        return ()
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        raise NotImplementedError()
+
+    def find_named_blocks(
+        self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]
+    ) -> None:
+        for child in self.each_child():
+            child.find_named_blocks(loader, named_blocks)
+
+
+class _File(_Node):
+    def __init__(self, template: Template, body: "_ChunkList") -> None:
+        self.template = template
+        self.body = body
+        self.line = 0
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        writer.write_line("def _tt_execute():", self.line)
+        with writer.indent():
+            writer.write_line("_tt_buffer = []", self.line)
+            writer.write_line("_tt_append = _tt_buffer.append", self.line)
+            self.body.generate(writer)
+            writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)
+
+    def each_child(self) -> Iterable["_Node"]:
+        return (self.body,)
+
+
+class _ChunkList(_Node):
+    def __init__(self, chunks: List[_Node]) -> None:
+        self.chunks = chunks
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        for chunk in self.chunks:
+            chunk.generate(writer)
+
+    def each_child(self) -> Iterable["_Node"]:
+        return self.chunks
+
+
+class _NamedBlock(_Node):
+    def __init__(self, name: str, body: _Node, template: Template, line: int) -> None:
+        self.name = name
+        self.body = body
+        self.template = template
+        self.line = line
+
+    def each_child(self) -> Iterable["_Node"]:
+        return (self.body,)
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        block = writer.named_blocks[self.name]
+        with writer.include(block.template, self.line):
+            block.body.generate(writer)
+
+    def find_named_blocks(
+        self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]
+    ) -> None:
+        named_blocks[self.name] = self
+        _Node.find_named_blocks(self, loader, named_blocks)
+
+
+class _ExtendsBlock(_Node):
+    def __init__(self, name: str) -> None:
+        self.name = name
+
+
+class _IncludeBlock(_Node):
+    def __init__(self, name: str, reader: "_TemplateReader", line: int) -> None:
+        self.name = name
+        self.template_name = reader.name
+        self.line = line
+
+    def find_named_blocks(
+        self, loader: Optional[BaseLoader], named_blocks: Dict[str, _NamedBlock]
+    ) -> None:
+        assert loader is not None
+        included = loader.load(self.name, self.template_name)
+        included.file.find_named_blocks(loader, named_blocks)
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        assert writer.loader is not None
+        included = writer.loader.load(self.name, self.template_name)
+        with writer.include(included, self.line):
+            included.file.body.generate(writer)
+
+
+class _ApplyBlock(_Node):
+    def __init__(self, method: str, line: int, body: _Node) -> None:
+        self.method = method
+        self.line = line
+        self.body = body
+
+    def each_child(self) -> Iterable["_Node"]:
+        return (self.body,)
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        method_name = "_tt_apply%d" % writer.apply_counter
+        writer.apply_counter += 1
+        writer.write_line("def %s():" % method_name, self.line)
+        with writer.indent():
+            writer.write_line("_tt_buffer = []", self.line)
+            writer.write_line("_tt_append = _tt_buffer.append", self.line)
+            self.body.generate(writer)
+            writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)
+        writer.write_line(
+            "_tt_append(_tt_utf8(%s(%s())))" % (self.method, method_name), self.line
+        )
+
+
+class _ControlBlock(_Node):
+    def __init__(self, statement: str, line: int, body: _Node) -> None:
+        self.statement = statement
+        self.line = line
+        self.body = body
+
+    def each_child(self) -> Iterable[_Node]:
+        return (self.body,)
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        writer.write_line("%s:" % self.statement, self.line)
+        with writer.indent():
+            self.body.generate(writer)
+            # Just in case the body was empty
+            writer.write_line("pass", self.line)
+
+
+class _IntermediateControlBlock(_Node):
+    def __init__(self, statement: str, line: int) -> None:
+        self.statement = statement
+        self.line = line
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        # In case the previous block was empty
+        writer.write_line("pass", self.line)
+        writer.write_line("%s:" % self.statement, self.line, writer.indent_size() - 1)
+
+
+class _Statement(_Node):
+    def __init__(self, statement: str, line: int) -> None:
+        self.statement = statement
+        self.line = line
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        writer.write_line(self.statement, self.line)
+
+
+class _Expression(_Node):
+    def __init__(self, expression: str, line: int, raw: bool = False) -> None:
+        self.expression = expression
+        self.line = line
+        self.raw = raw
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        writer.write_line("_tt_tmp = %s" % self.expression, self.line)
+        writer.write_line(
+            "if isinstance(_tt_tmp, _tt_string_types):" " _tt_tmp = _tt_utf8(_tt_tmp)",
+            self.line,
+        )
+        writer.write_line("else: _tt_tmp = _tt_utf8(str(_tt_tmp))", self.line)
+        if not self.raw and writer.current_template.autoescape is not None:
+            # In python3 functions like xhtml_escape return unicode,
+            # so we have to convert to utf8 again.
+            writer.write_line(
+                "_tt_tmp = _tt_utf8(%s(_tt_tmp))" % writer.current_template.autoescape,
+                self.line,
+            )
+        writer.write_line("_tt_append(_tt_tmp)", self.line)
+
+
+class _Module(_Expression):
+    def __init__(self, expression: str, line: int) -> None:
+        super().__init__("_tt_modules." + expression, line, raw=True)
+
+
+class _Text(_Node):
+    def __init__(self, value: str, line: int, whitespace: str) -> None:
+        self.value = value
+        self.line = line
+        self.whitespace = whitespace
+
+    def generate(self, writer: "_CodeWriter") -> None:
+        value = self.value
+
+        # Compress whitespace if requested, with a crude heuristic to avoid
+        # altering preformatted whitespace.
+        if "<pre>" not in value:
+            value = filter_whitespace(self.whitespace, value)
+
+        if value:
+            writer.write_line("_tt_append(%r)" % escape.utf8(value), self.line)
+
+
+class ParseError(Exception):
+    """Raised for template syntax errors.
+
+    ``ParseError`` instances have ``filename`` and ``lineno`` attributes
+    indicating the position of the error.
+
+    .. versionchanged:: 4.3
+       Added ``filename`` and ``lineno`` attributes.
+    """
+
+    def __init__(
+        self, message: str, filename: Optional[str] = None, lineno: int = 0
+    ) -> None:
+        self.message = message
+        # The names "filename" and "lineno" are chosen for consistency
+        # with python SyntaxError.
+        self.filename = filename
+        self.lineno = lineno
+
+    def __str__(self) -> str:
+        return "%s at %s:%d" % (self.message, self.filename, self.lineno)
+
+
+class _CodeWriter(object):
+    def __init__(
+        self,
+        file: TextIO,
+        named_blocks: Dict[str, _NamedBlock],
+        loader: Optional[BaseLoader],
+        current_template: Template,
+    ) -> None:
+        self.file = file
+        self.named_blocks = named_blocks
+        self.loader = loader
+        self.current_template = current_template
+        self.apply_counter = 0
+        self.include_stack = []  # type: List[Tuple[Template, int]]
+        self._indent = 0
+
+    def indent_size(self) -> int:
+        return self._indent
+
+    def indent(self) -> "ContextManager":
+        class Indenter(object):
+            def __enter__(_) -> "_CodeWriter":
+                self._indent += 1
+                return self
+
+            def __exit__(_, *args: Any) -> None:
+                assert self._indent > 0
+                self._indent -= 1
+
+        return Indenter()
+
+    def include(self, template: Template, line: int) -> "ContextManager":
+        self.include_stack.append((self.current_template, line))
+        self.current_template = template
+
+        class IncludeTemplate(object):
+            def __enter__(_) -> "_CodeWriter":
+                return self
+
+            def __exit__(_, *args: Any) -> None:
+                self.current_template = self.include_stack.pop()[0]
+
+        return IncludeTemplate()
+
+    def write_line(
+        self, line: str, line_number: int, indent: Optional[int] = None
+    ) -> None:
+        if indent is None:
+            indent = self._indent
+        line_comment = "  # %s:%d" % (self.current_template.name, line_number)
+        if self.include_stack:
+            ancestors = [
+                "%s:%d" % (tmpl.name, lineno) for (tmpl, lineno) in self.include_stack
+            ]
+            line_comment += " (via %s)" % ", ".join(reversed(ancestors))
+        print("    " * indent + line + line_comment, file=self.file)
+
+
+class _TemplateReader(object):
+    def __init__(self, name: str, text: str, whitespace: str) -> None:
+        self.name = name
+        self.text = text
+        self.whitespace = whitespace
+        self.line = 1
+        self.pos = 0
+
+    def find(self, needle: str, start: int = 0, end: Optional[int] = None) -> int:
+        assert start >= 0, start
+        pos = self.pos
+        start += pos
+        if end is None:
+            index = self.text.find(needle, start)
+        else:
+            end += pos
+            assert end >= start
+            index = self.text.find(needle, start, end)
+        if index != -1:
+            index -= pos
+        return index
+
+    def consume(self, count: Optional[int] = None) -> str:
+        if count is None:
+            count = len(self.text) - self.pos
+        newpos = self.pos + count
+        self.line += self.text.count("\n", self.pos, newpos)
+        s = self.text[self.pos : newpos]
+        self.pos = newpos
+        return s
+
+    def remaining(self) -> int:
+        return len(self.text) - self.pos
+
+    def __len__(self) -> int:
+        return self.remaining()
+
+    def __getitem__(self, key: Union[int, slice]) -> str:
+        if isinstance(key, slice):
+            size = len(self)
+            start, stop, step = key.indices(size)
+            if start is None:
+                start = self.pos
+            else:
+                start += self.pos
+            if stop is not None:
+                stop += self.pos
+            return self.text[slice(start, stop, step)]
+        elif key < 0:
+            return self.text[key]
+        else:
+            return self.text[self.pos + key]
+
+    def __str__(self) -> str:
+        return self.text[self.pos :]
+
+    def raise_parse_error(self, msg: str) -> None:
+        raise ParseError(msg, self.name, self.line)
+
+
+def _format_code(code: str) -> str:
+    lines = code.splitlines()
+    format = "%%%dd  %%s\n" % len(repr(len(lines) + 1))
+    return "".join([format % (i + 1, line) for (i, line) in enumerate(lines)])
+
+
+def _parse(
+    reader: _TemplateReader,
+    template: Template,
+    in_block: Optional[str] = None,
+    in_loop: Optional[str] = None,
+) -> _ChunkList:
+    body = _ChunkList([])
+    while True:
+        # Find next template directive
+        curly = 0
+        while True:
+            curly = reader.find("{", curly)
+            if curly == -1 or curly + 1 == reader.remaining():
+                # EOF
+                if in_block:
+                    reader.raise_parse_error(
+                        "Missing {%% end %%} block for %s" % in_block
+                    )
+                body.chunks.append(
+                    _Text(reader.consume(), reader.line, reader.whitespace)
+                )
+                return body
+            # If the first curly brace is not the start of a special token,
+            # start searching from the character after it
+            if reader[curly + 1] not in ("{", "%", "#"):
+                curly += 1
+                continue
+            # When there are more than 2 curlies in a row, use the
+            # innermost ones.  This is useful when generating languages
+            # like latex where curlies are also meaningful
+            if (
+                curly + 2 < reader.remaining()
+                and reader[curly + 1] == "{"
+                and reader[curly + 2] == "{"
+            ):
+                curly += 1
+                continue
+            break
+
+        # Append any text before the special token
+        if curly > 0:
+            cons = reader.consume(curly)
+            body.chunks.append(_Text(cons, reader.line, reader.whitespace))
+
+        start_brace = reader.consume(2)
+        line = reader.line
+
+        # Template directives may be escaped as "{{!" or "{%!".
+        # In this case output the braces and consume the "!".
+        # This is especially useful in conjunction with jquery templates,
+        # which also use double braces.
+        if reader.remaining() and reader[0] == "!":
+            reader.consume(1)
+            body.chunks.append(_Text(start_brace, line, reader.whitespace))
+            continue
+
+        # Comment
+        if start_brace == "{#":
+            end = reader.find("#}")
+            if end == -1:
+                reader.raise_parse_error("Missing end comment #}")
+            contents = reader.consume(end).strip()
+            reader.consume(2)
+            continue
+
+        # Expression
+        if start_brace == "{{":
+            end = reader.find("}}")
+            if end == -1:
+                reader.raise_parse_error("Missing end expression }}")
+            contents = reader.consume(end).strip()
+            reader.consume(2)
+            if not contents:
+                reader.raise_parse_error("Empty expression")
+            body.chunks.append(_Expression(contents, line))
+            continue
+
+        # Block
+        assert start_brace == "{%", start_brace
+        end = reader.find("%}")
+        if end == -1:
+            reader.raise_parse_error("Missing end block %}")
+        contents = reader.consume(end).strip()
+        reader.consume(2)
+        if not contents:
+            reader.raise_parse_error("Empty block tag ({% %})")
+
+        operator, space, suffix = contents.partition(" ")
+        suffix = suffix.strip()
+
+        # Intermediate ("else", "elif", etc) blocks
+        intermediate_blocks = {
+            "else": set(["if", "for", "while", "try"]),
+            "elif": set(["if"]),
+            "except": set(["try"]),
+            "finally": set(["try"]),
+        }
+        allowed_parents = intermediate_blocks.get(operator)
+        if allowed_parents is not None:
+            if not in_block:
+                reader.raise_parse_error(
+                    "%s outside %s block" % (operator, allowed_parents)
+                )
+            if in_block not in allowed_parents:
+                reader.raise_parse_error(
+                    "%s block cannot be attached to %s block" % (operator, in_block)
+                )
+            body.chunks.append(_IntermediateControlBlock(contents, line))
+            continue
+
+        # End tag
+        elif operator == "end":
+            if not in_block:
+                reader.raise_parse_error("Extra {% end %} block")
+            return body
+
+        elif operator in (
+            "extends",
+            "include",
+            "set",
+            "import",
+            "from",
+            "comment",
+            "autoescape",
+            "whitespace",
+            "raw",
+            "module",
+        ):
+            if operator == "comment":
+                continue
+            if operator == "extends":
+                suffix = suffix.strip('"').strip("'")
+                if not suffix:
+                    reader.raise_parse_error("extends missing file path")
+                block = _ExtendsBlock(suffix)  # type: _Node
+            elif operator in ("import", "from"):
+                if not suffix:
+                    reader.raise_parse_error("import missing statement")
+                block = _Statement(contents, line)
+            elif operator == "include":
+                suffix = suffix.strip('"').strip("'")
+                if not suffix:
+                    reader.raise_parse_error("include missing file path")
+                block = _IncludeBlock(suffix, reader, line)
+            elif operator == "set":
+                if not suffix:
+                    reader.raise_parse_error("set missing statement")
+                block = _Statement(suffix, line)
+            elif operator == "autoescape":
+                fn = suffix.strip()  # type: Optional[str]
+                if fn == "None":
+                    fn = None
+                template.autoescape = fn
+                continue
+            elif operator == "whitespace":
+                mode = suffix.strip()
+                # Validate the selected mode
+                filter_whitespace(mode, "")
+                reader.whitespace = mode
+                continue
+            elif operator == "raw":
+                block = _Expression(suffix, line, raw=True)
+            elif operator == "module":
+                block = _Module(suffix, line)
+            body.chunks.append(block)
+            continue
+
+        elif operator in ("apply", "block", "try", "if", "for", "while"):
+            # parse inner body recursively
+            if operator in ("for", "while"):
+                block_body = _parse(reader, template, operator, operator)
+            elif operator == "apply":
+                # apply creates a nested function so syntactically it's not
+                # in the loop.
+                block_body = _parse(reader, template, operator, None)
+            else:
+                block_body = _parse(reader, template, operator, in_loop)
+
+            if operator == "apply":
+                if not suffix:
+                    reader.raise_parse_error("apply missing method name")
+                block = _ApplyBlock(suffix, line, block_body)
+            elif operator == "block":
+                if not suffix:
+                    reader.raise_parse_error("block missing name")
+                block = _NamedBlock(suffix, block_body, template, line)
+            else:
+                block = _ControlBlock(contents, line, block_body)
+            body.chunks.append(block)
+            continue
+
+        elif operator in ("break", "continue"):
+            if not in_loop:
+                reader.raise_parse_error(
+                    "%s outside %s block" % (operator, set(["for", "while"]))
+                )
+            body.chunks.append(_Statement(contents, line))
+            continue
+
+        else:
+            reader.raise_parse_error("unknown operator: %r" % operator)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/__init__.py b/venv/lib/python3.9/site-packages/tornado/test/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/__init__.py
diff --git a/venv/lib/python3.9/site-packages/tornado/test/__main__.py b/venv/lib/python3.9/site-packages/tornado/test/__main__.py
new file mode 100644
index 00000000..430c895f
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/__main__.py
@@ -0,0 +1,12 @@
+"""Shim to allow python -m tornado.test.
+
+This only works in python 2.7+.
+"""
+from tornado.test.runtests import all, main
+
+# tornado.testing.main autodiscovery relies on 'all' being present in
+# the main module, so import it here even though it is not used directly.
+# The following line prevents a pyflakes warning.
+all = all
+
+main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/asyncio_test.py b/venv/lib/python3.9/site-packages/tornado/test/asyncio_test.py
new file mode 100644
index 00000000..348c0ceb
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/asyncio_test.py
@@ -0,0 +1,209 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import asyncio
+import unittest
+import warnings
+
+from concurrent.futures import ThreadPoolExecutor
+from tornado import gen
+from tornado.ioloop import IOLoop
+from tornado.platform.asyncio import (
+    AsyncIOLoop,
+    to_asyncio_future,
+    AnyThreadEventLoopPolicy,
+)
+from tornado.testing import AsyncTestCase, gen_test
+
+
+class AsyncIOLoopTest(AsyncTestCase):
+    @property
+    def asyncio_loop(self):
+        return self.io_loop.asyncio_loop  # type: ignore
+
+    def test_asyncio_callback(self):
+        # Basic test that the asyncio loop is set up correctly.
+        async def add_callback():
+            asyncio.get_event_loop().call_soon(self.stop)
+
+        self.asyncio_loop.run_until_complete(add_callback())
+        self.wait()
+
+    @gen_test
+    def test_asyncio_future(self):
+        # Test that we can yield an asyncio future from a tornado coroutine.
+        # Without 'yield from', we must wrap coroutines in ensure_future,
+        # which was introduced during Python 3.4, deprecating the prior "async".
+        if hasattr(asyncio, "ensure_future"):
+            ensure_future = asyncio.ensure_future
+        else:
+            # async is a reserved word in Python 3.7
+            ensure_future = getattr(asyncio, "async")
+
+        x = yield ensure_future(
+            asyncio.get_event_loop().run_in_executor(None, lambda: 42)
+        )
+        self.assertEqual(x, 42)
+
+    @gen_test
+    def test_asyncio_yield_from(self):
+        @gen.coroutine
+        def f():
+            event_loop = asyncio.get_event_loop()
+            x = yield from event_loop.run_in_executor(None, lambda: 42)
+            return x
+
+        result = yield f()
+        self.assertEqual(result, 42)
+
+    def test_asyncio_adapter(self):
+        # This test demonstrates that when using the asyncio coroutine
+        # runner (i.e. run_until_complete), the to_asyncio_future
+        # adapter is needed. No adapter is needed in the other direction,
+        # as demonstrated by other tests in the package.
+        @gen.coroutine
+        def tornado_coroutine():
+            yield gen.moment
+            raise gen.Return(42)
+
+        async def native_coroutine_without_adapter():
+            return await tornado_coroutine()
+
+        async def native_coroutine_with_adapter():
+            return await to_asyncio_future(tornado_coroutine())
+
+        # Use the adapter, but two degrees from the tornado coroutine.
+        async def native_coroutine_with_adapter2():
+            return await to_asyncio_future(native_coroutine_without_adapter())
+
+        # Tornado supports native coroutines both with and without adapters
+        self.assertEqual(self.io_loop.run_sync(native_coroutine_without_adapter), 42)
+        self.assertEqual(self.io_loop.run_sync(native_coroutine_with_adapter), 42)
+        self.assertEqual(self.io_loop.run_sync(native_coroutine_with_adapter2), 42)
+
+        # Asyncio only supports coroutines that yield asyncio-compatible
+        # Futures (which our Future is since 5.0).
+        self.assertEqual(
+            self.asyncio_loop.run_until_complete(native_coroutine_without_adapter()),
+            42,
+        )
+        self.assertEqual(
+            self.asyncio_loop.run_until_complete(native_coroutine_with_adapter()),
+            42,
+        )
+        self.assertEqual(
+            self.asyncio_loop.run_until_complete(native_coroutine_with_adapter2()),
+            42,
+        )
+
+
+class LeakTest(unittest.TestCase):
+    def setUp(self):
+        # Trigger a cleanup of the mapping so we start with a clean slate.
+        AsyncIOLoop(make_current=False).close()
+        # If we don't clean up after ourselves other tests may fail on
+        # py34.
+        self.orig_policy = asyncio.get_event_loop_policy()
+        asyncio.set_event_loop_policy(asyncio.DefaultEventLoopPolicy())
+
+    def tearDown(self):
+        try:
+            loop = asyncio.get_event_loop_policy().get_event_loop()
+        except Exception:
+            # We may not have a current event loop at this point.
+            pass
+        else:
+            loop.close()
+        asyncio.set_event_loop_policy(self.orig_policy)
+
+    def test_ioloop_close_leak(self):
+        orig_count = len(IOLoop._ioloop_for_asyncio)
+        for i in range(10):
+            # Create and close an AsyncIOLoop using Tornado interfaces.
+            with warnings.catch_warnings():
+                warnings.simplefilter("ignore", DeprecationWarning)
+                loop = AsyncIOLoop()
+                loop.close()
+        new_count = len(IOLoop._ioloop_for_asyncio) - orig_count
+        self.assertEqual(new_count, 0)
+
+    def test_asyncio_close_leak(self):
+        orig_count = len(IOLoop._ioloop_for_asyncio)
+        for i in range(10):
+            # Create and close an AsyncIOMainLoop using asyncio interfaces.
+            loop = asyncio.new_event_loop()
+            loop.call_soon(IOLoop.current)
+            loop.call_soon(loop.stop)
+            loop.run_forever()
+            loop.close()
+        new_count = len(IOLoop._ioloop_for_asyncio) - orig_count
+        # Because the cleanup is run on new loop creation, we have one
+        # dangling entry in the map (but only one).
+        self.assertEqual(new_count, 1)
+
+
+class AnyThreadEventLoopPolicyTest(unittest.TestCase):
+    def setUp(self):
+        self.orig_policy = asyncio.get_event_loop_policy()
+        self.executor = ThreadPoolExecutor(1)
+
+    def tearDown(self):
+        asyncio.set_event_loop_policy(self.orig_policy)
+        self.executor.shutdown()
+
+    def get_event_loop_on_thread(self):
+        def get_and_close_event_loop():
+            """Get the event loop. Close it if one is returned.
+
+            Returns the (closed) event loop. This is a silly thing
+            to do and leaves the thread in a broken state, but it's
+            enough for this test. Closing the loop avoids resource
+            leak warnings.
+            """
+            loop = asyncio.get_event_loop()
+            loop.close()
+            return loop
+
+        future = self.executor.submit(get_and_close_event_loop)
+        return future.result()
+
+    def test_asyncio_accessor(self):
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            # With the default policy, non-main threads don't get an event
+            # loop.
+            self.assertRaises(
+                RuntimeError, self.executor.submit(asyncio.get_event_loop).result
+            )
+            # Set the policy and we can get a loop.
+            asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
+            self.assertIsInstance(
+                self.executor.submit(asyncio.get_event_loop).result(),
+                asyncio.AbstractEventLoop,
+            )
+            # Clean up to silence leak warnings. Always use asyncio since
+            # IOLoop doesn't (currently) close the underlying loop.
+            self.executor.submit(lambda: asyncio.get_event_loop().close()).result()  # type: ignore
+
+    def test_tornado_accessor(self):
+        # Tornado's IOLoop.current() API can create a loop for any thread,
+        # regardless of this event loop policy.
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            self.assertIsInstance(self.executor.submit(IOLoop.current).result(), IOLoop)
+            # Clean up to silence leak warnings. Always use asyncio since
+            # IOLoop doesn't (currently) close the underlying loop.
+            self.executor.submit(lambda: asyncio.get_event_loop().close()).result()  # type: ignore
+
+            asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
+            self.assertIsInstance(self.executor.submit(IOLoop.current).result(), IOLoop)
+            self.executor.submit(lambda: asyncio.get_event_loop().close()).result()  # type: ignore
diff --git a/venv/lib/python3.9/site-packages/tornado/test/auth_test.py b/venv/lib/python3.9/site-packages/tornado/test/auth_test.py
new file mode 100644
index 00000000..3cd715f7
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/auth_test.py
@@ -0,0 +1,609 @@
+# These tests do not currently do much to verify the correct implementation
+# of the openid/oauth protocols, they just exercise the major code paths
+# and ensure that it doesn't blow up (e.g. with unicode/bytes issues in
+# python 3)
+
+import unittest
+
+from tornado.auth import (
+    OpenIdMixin,
+    OAuthMixin,
+    OAuth2Mixin,
+    GoogleOAuth2Mixin,
+    FacebookGraphMixin,
+    TwitterMixin,
+)
+from tornado.escape import json_decode
+from tornado import gen
+from tornado.httpclient import HTTPClientError
+from tornado.httputil import url_concat
+from tornado.log import app_log
+from tornado.testing import AsyncHTTPTestCase, ExpectLog
+from tornado.web import RequestHandler, Application, HTTPError
+
+try:
+    from unittest import mock
+except ImportError:
+    mock = None  # type: ignore
+
+
+class OpenIdClientLoginHandler(RequestHandler, OpenIdMixin):
+    def initialize(self, test):
+        self._OPENID_ENDPOINT = test.get_url("/openid/server/authenticate")
+
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("openid.mode", None):
+            user = yield self.get_authenticated_user(
+                http_client=self.settings["http_client"]
+            )
+            if user is None:
+                raise Exception("user is None")
+            self.finish(user)
+            return
+        res = self.authenticate_redirect()  # type: ignore
+        assert res is None
+
+
+class OpenIdServerAuthenticateHandler(RequestHandler):
+    def post(self):
+        if self.get_argument("openid.mode") != "check_authentication":
+            raise Exception("incorrect openid.mode %r")
+        self.write("is_valid:true")
+
+
+class OAuth1ClientLoginHandler(RequestHandler, OAuthMixin):
+    def initialize(self, test, version):
+        self._OAUTH_VERSION = version
+        self._OAUTH_REQUEST_TOKEN_URL = test.get_url("/oauth1/server/request_token")
+        self._OAUTH_AUTHORIZE_URL = test.get_url("/oauth1/server/authorize")
+        self._OAUTH_ACCESS_TOKEN_URL = test.get_url("/oauth1/server/access_token")
+
+    def _oauth_consumer_token(self):
+        return dict(key="asdf", secret="qwer")
+
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("oauth_token", None):
+            user = yield self.get_authenticated_user(
+                http_client=self.settings["http_client"]
+            )
+            if user is None:
+                raise Exception("user is None")
+            self.finish(user)
+            return
+        yield self.authorize_redirect(http_client=self.settings["http_client"])
+
+    @gen.coroutine
+    def _oauth_get_user_future(self, access_token):
+        if self.get_argument("fail_in_get_user", None):
+            raise Exception("failing in get_user")
+        if access_token != dict(key="uiop", secret="5678"):
+            raise Exception("incorrect access token %r" % access_token)
+        return dict(email="foo@example.com")
+
+
+class OAuth1ClientLoginCoroutineHandler(OAuth1ClientLoginHandler):
+    """Replaces OAuth1ClientLoginCoroutineHandler's get() with a coroutine."""
+
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("oauth_token", None):
+            # Ensure that any exceptions are set on the returned Future,
+            # not simply thrown into the surrounding StackContext.
+            try:
+                yield self.get_authenticated_user()
+            except Exception as e:
+                self.set_status(503)
+                self.write("got exception: %s" % e)
+        else:
+            yield self.authorize_redirect()
+
+
+class OAuth1ClientRequestParametersHandler(RequestHandler, OAuthMixin):
+    def initialize(self, version):
+        self._OAUTH_VERSION = version
+
+    def _oauth_consumer_token(self):
+        return dict(key="asdf", secret="qwer")
+
+    def get(self):
+        params = self._oauth_request_parameters(
+            "http://www.example.com/api/asdf",
+            dict(key="uiop", secret="5678"),
+            parameters=dict(foo="bar"),
+        )
+        self.write(params)
+
+
+class OAuth1ServerRequestTokenHandler(RequestHandler):
+    def get(self):
+        self.write("oauth_token=zxcv&oauth_token_secret=1234")
+
+
+class OAuth1ServerAccessTokenHandler(RequestHandler):
+    def get(self):
+        self.write("oauth_token=uiop&oauth_token_secret=5678")
+
+
+class OAuth2ClientLoginHandler(RequestHandler, OAuth2Mixin):
+    def initialize(self, test):
+        self._OAUTH_AUTHORIZE_URL = test.get_url("/oauth2/server/authorize")
+
+    def get(self):
+        res = self.authorize_redirect()  # type: ignore
+        assert res is None
+
+
+class FacebookClientLoginHandler(RequestHandler, FacebookGraphMixin):
+    def initialize(self, test):
+        self._OAUTH_AUTHORIZE_URL = test.get_url("/facebook/server/authorize")
+        self._OAUTH_ACCESS_TOKEN_URL = test.get_url("/facebook/server/access_token")
+        self._FACEBOOK_BASE_URL = test.get_url("/facebook/server")
+
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("code", None):
+            user = yield self.get_authenticated_user(
+                redirect_uri=self.request.full_url(),
+                client_id=self.settings["facebook_api_key"],
+                client_secret=self.settings["facebook_secret"],
+                code=self.get_argument("code"),
+            )
+            self.write(user)
+        else:
+            self.authorize_redirect(
+                redirect_uri=self.request.full_url(),
+                client_id=self.settings["facebook_api_key"],
+                extra_params={"scope": "read_stream,offline_access"},
+            )
+
+
+class FacebookServerAccessTokenHandler(RequestHandler):
+    def get(self):
+        self.write(dict(access_token="asdf", expires_in=3600))
+
+
+class FacebookServerMeHandler(RequestHandler):
+    def get(self):
+        self.write("{}")
+
+
+class TwitterClientHandler(RequestHandler, TwitterMixin):
+    def initialize(self, test):
+        self._OAUTH_REQUEST_TOKEN_URL = test.get_url("/oauth1/server/request_token")
+        self._OAUTH_ACCESS_TOKEN_URL = test.get_url("/twitter/server/access_token")
+        self._OAUTH_AUTHORIZE_URL = test.get_url("/oauth1/server/authorize")
+        self._OAUTH_AUTHENTICATE_URL = test.get_url("/twitter/server/authenticate")
+        self._TWITTER_BASE_URL = test.get_url("/twitter/api")
+
+    def get_auth_http_client(self):
+        return self.settings["http_client"]
+
+
+class TwitterClientLoginHandler(TwitterClientHandler):
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("oauth_token", None):
+            user = yield self.get_authenticated_user()
+            if user is None:
+                raise Exception("user is None")
+            self.finish(user)
+            return
+        yield self.authorize_redirect()
+
+
+class TwitterClientAuthenticateHandler(TwitterClientHandler):
+    # Like TwitterClientLoginHandler, but uses authenticate_redirect
+    # instead of authorize_redirect.
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("oauth_token", None):
+            user = yield self.get_authenticated_user()
+            if user is None:
+                raise Exception("user is None")
+            self.finish(user)
+            return
+        yield self.authenticate_redirect()
+
+
+class TwitterClientLoginGenCoroutineHandler(TwitterClientHandler):
+    @gen.coroutine
+    def get(self):
+        if self.get_argument("oauth_token", None):
+            user = yield self.get_authenticated_user()
+            self.finish(user)
+        else:
+            # New style: with @gen.coroutine the result must be yielded
+            # or else the request will be auto-finished too soon.
+            yield self.authorize_redirect()
+
+
+class TwitterClientShowUserHandler(TwitterClientHandler):
+    @gen.coroutine
+    def get(self):
+        # TODO: would be nice to go through the login flow instead of
+        # cheating with a hard-coded access token.
+        try:
+            response = yield self.twitter_request(
+                "/users/show/%s" % self.get_argument("name"),
+                access_token=dict(key="hjkl", secret="vbnm"),
+            )
+        except HTTPClientError:
+            # TODO(bdarnell): Should we catch HTTP errors and
+            # transform some of them (like 403s) into AuthError?
+            self.set_status(500)
+            self.finish("error from twitter request")
+        else:
+            self.finish(response)
+
+
+class TwitterServerAccessTokenHandler(RequestHandler):
+    def get(self):
+        self.write("oauth_token=hjkl&oauth_token_secret=vbnm&screen_name=foo")
+
+
+class TwitterServerShowUserHandler(RequestHandler):
+    def get(self, screen_name):
+        if screen_name == "error":
+            raise HTTPError(500)
+        assert "oauth_nonce" in self.request.arguments
+        assert "oauth_timestamp" in self.request.arguments
+        assert "oauth_signature" in self.request.arguments
+        assert self.get_argument("oauth_consumer_key") == "test_twitter_consumer_key"
+        assert self.get_argument("oauth_signature_method") == "HMAC-SHA1"
+        assert self.get_argument("oauth_version") == "1.0"
+        assert self.get_argument("oauth_token") == "hjkl"
+        self.write(dict(screen_name=screen_name, name=screen_name.capitalize()))
+
+
+class TwitterServerVerifyCredentialsHandler(RequestHandler):
+    def get(self):
+        assert "oauth_nonce" in self.request.arguments
+        assert "oauth_timestamp" in self.request.arguments
+        assert "oauth_signature" in self.request.arguments
+        assert self.get_argument("oauth_consumer_key") == "test_twitter_consumer_key"
+        assert self.get_argument("oauth_signature_method") == "HMAC-SHA1"
+        assert self.get_argument("oauth_version") == "1.0"
+        assert self.get_argument("oauth_token") == "hjkl"
+        self.write(dict(screen_name="foo", name="Foo"))
+
+
+class AuthTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application(
+            [
+                # test endpoints
+                ("/openid/client/login", OpenIdClientLoginHandler, dict(test=self)),
+                (
+                    "/oauth10/client/login",
+                    OAuth1ClientLoginHandler,
+                    dict(test=self, version="1.0"),
+                ),
+                (
+                    "/oauth10/client/request_params",
+                    OAuth1ClientRequestParametersHandler,
+                    dict(version="1.0"),
+                ),
+                (
+                    "/oauth10a/client/login",
+                    OAuth1ClientLoginHandler,
+                    dict(test=self, version="1.0a"),
+                ),
+                (
+                    "/oauth10a/client/login_coroutine",
+                    OAuth1ClientLoginCoroutineHandler,
+                    dict(test=self, version="1.0a"),
+                ),
+                (
+                    "/oauth10a/client/request_params",
+                    OAuth1ClientRequestParametersHandler,
+                    dict(version="1.0a"),
+                ),
+                ("/oauth2/client/login", OAuth2ClientLoginHandler, dict(test=self)),
+                ("/facebook/client/login", FacebookClientLoginHandler, dict(test=self)),
+                ("/twitter/client/login", TwitterClientLoginHandler, dict(test=self)),
+                (
+                    "/twitter/client/authenticate",
+                    TwitterClientAuthenticateHandler,
+                    dict(test=self),
+                ),
+                (
+                    "/twitter/client/login_gen_coroutine",
+                    TwitterClientLoginGenCoroutineHandler,
+                    dict(test=self),
+                ),
+                (
+                    "/twitter/client/show_user",
+                    TwitterClientShowUserHandler,
+                    dict(test=self),
+                ),
+                # simulated servers
+                ("/openid/server/authenticate", OpenIdServerAuthenticateHandler),
+                ("/oauth1/server/request_token", OAuth1ServerRequestTokenHandler),
+                ("/oauth1/server/access_token", OAuth1ServerAccessTokenHandler),
+                ("/facebook/server/access_token", FacebookServerAccessTokenHandler),
+                ("/facebook/server/me", FacebookServerMeHandler),
+                ("/twitter/server/access_token", TwitterServerAccessTokenHandler),
+                (r"/twitter/api/users/show/(.*)\.json", TwitterServerShowUserHandler),
+                (
+                    r"/twitter/api/account/verify_credentials\.json",
+                    TwitterServerVerifyCredentialsHandler,
+                ),
+            ],
+            http_client=self.http_client,
+            twitter_consumer_key="test_twitter_consumer_key",
+            twitter_consumer_secret="test_twitter_consumer_secret",
+            facebook_api_key="test_facebook_api_key",
+            facebook_secret="test_facebook_secret",
+        )
+
+    def test_openid_redirect(self):
+        response = self.fetch("/openid/client/login", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue("/openid/server/authenticate?" in response.headers["Location"])
+
+    def test_openid_get_user(self):
+        response = self.fetch(
+            "/openid/client/login?openid.mode=blah"
+            "&openid.ns.ax=http://openid.net/srv/ax/1.0"
+            "&openid.ax.type.email=http://axschema.org/contact/email"
+            "&openid.ax.value.email=foo@example.com"
+        )
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(parsed["email"], "foo@example.com")
+
+    def test_oauth10_redirect(self):
+        response = self.fetch("/oauth10/client/login", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue(
+            response.headers["Location"].endswith(
+                "/oauth1/server/authorize?oauth_token=zxcv"
+            )
+        )
+        # the cookie is base64('zxcv')|base64('1234')
+        self.assertTrue(
+            '_oauth_request_token="enhjdg==|MTIzNA=="'
+            in response.headers["Set-Cookie"],
+            response.headers["Set-Cookie"],
+        )
+
+    def test_oauth10_get_user(self):
+        response = self.fetch(
+            "/oauth10/client/login?oauth_token=zxcv",
+            headers={"Cookie": "_oauth_request_token=enhjdg==|MTIzNA=="},
+        )
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(parsed["email"], "foo@example.com")
+        self.assertEqual(parsed["access_token"], dict(key="uiop", secret="5678"))
+
+    def test_oauth10_request_parameters(self):
+        response = self.fetch("/oauth10/client/request_params")
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(parsed["oauth_consumer_key"], "asdf")
+        self.assertEqual(parsed["oauth_token"], "uiop")
+        self.assertTrue("oauth_nonce" in parsed)
+        self.assertTrue("oauth_signature" in parsed)
+
+    def test_oauth10a_redirect(self):
+        response = self.fetch("/oauth10a/client/login", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue(
+            response.headers["Location"].endswith(
+                "/oauth1/server/authorize?oauth_token=zxcv"
+            )
+        )
+        # the cookie is base64('zxcv')|base64('1234')
+        self.assertTrue(
+            '_oauth_request_token="enhjdg==|MTIzNA=="'
+            in response.headers["Set-Cookie"],
+            response.headers["Set-Cookie"],
+        )
+
+    @unittest.skipIf(mock is None, "mock package not present")
+    def test_oauth10a_redirect_error(self):
+        with mock.patch.object(OAuth1ServerRequestTokenHandler, "get") as get:
+            get.side_effect = Exception("boom")
+            with ExpectLog(app_log, "Uncaught exception"):
+                response = self.fetch("/oauth10a/client/login", follow_redirects=False)
+            self.assertEqual(response.code, 500)
+
+    def test_oauth10a_get_user(self):
+        response = self.fetch(
+            "/oauth10a/client/login?oauth_token=zxcv",
+            headers={"Cookie": "_oauth_request_token=enhjdg==|MTIzNA=="},
+        )
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(parsed["email"], "foo@example.com")
+        self.assertEqual(parsed["access_token"], dict(key="uiop", secret="5678"))
+
+    def test_oauth10a_request_parameters(self):
+        response = self.fetch("/oauth10a/client/request_params")
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(parsed["oauth_consumer_key"], "asdf")
+        self.assertEqual(parsed["oauth_token"], "uiop")
+        self.assertTrue("oauth_nonce" in parsed)
+        self.assertTrue("oauth_signature" in parsed)
+
+    def test_oauth10a_get_user_coroutine_exception(self):
+        response = self.fetch(
+            "/oauth10a/client/login_coroutine?oauth_token=zxcv&fail_in_get_user=true",
+            headers={"Cookie": "_oauth_request_token=enhjdg==|MTIzNA=="},
+        )
+        self.assertEqual(response.code, 503)
+
+    def test_oauth2_redirect(self):
+        response = self.fetch("/oauth2/client/login", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue("/oauth2/server/authorize?" in response.headers["Location"])
+
+    def test_facebook_login(self):
+        response = self.fetch("/facebook/client/login", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue("/facebook/server/authorize?" in response.headers["Location"])
+        response = self.fetch(
+            "/facebook/client/login?code=1234", follow_redirects=False
+        )
+        self.assertEqual(response.code, 200)
+        user = json_decode(response.body)
+        self.assertEqual(user["access_token"], "asdf")
+        self.assertEqual(user["session_expires"], "3600")
+
+    def base_twitter_redirect(self, url):
+        # Same as test_oauth10a_redirect
+        response = self.fetch(url, follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue(
+            response.headers["Location"].endswith(
+                "/oauth1/server/authorize?oauth_token=zxcv"
+            )
+        )
+        # the cookie is base64('zxcv')|base64('1234')
+        self.assertTrue(
+            '_oauth_request_token="enhjdg==|MTIzNA=="'
+            in response.headers["Set-Cookie"],
+            response.headers["Set-Cookie"],
+        )
+
+    def test_twitter_redirect(self):
+        self.base_twitter_redirect("/twitter/client/login")
+
+    def test_twitter_redirect_gen_coroutine(self):
+        self.base_twitter_redirect("/twitter/client/login_gen_coroutine")
+
+    def test_twitter_authenticate_redirect(self):
+        response = self.fetch("/twitter/client/authenticate", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue(
+            response.headers["Location"].endswith(
+                "/twitter/server/authenticate?oauth_token=zxcv"
+            ),
+            response.headers["Location"],
+        )
+        # the cookie is base64('zxcv')|base64('1234')
+        self.assertTrue(
+            '_oauth_request_token="enhjdg==|MTIzNA=="'
+            in response.headers["Set-Cookie"],
+            response.headers["Set-Cookie"],
+        )
+
+    def test_twitter_get_user(self):
+        response = self.fetch(
+            "/twitter/client/login?oauth_token=zxcv",
+            headers={"Cookie": "_oauth_request_token=enhjdg==|MTIzNA=="},
+        )
+        response.rethrow()
+        parsed = json_decode(response.body)
+        self.assertEqual(
+            parsed,
+            {
+                "access_token": {
+                    "key": "hjkl",
+                    "screen_name": "foo",
+                    "secret": "vbnm",
+                },
+                "name": "Foo",
+                "screen_name": "foo",
+                "username": "foo",
+            },
+        )
+
+    def test_twitter_show_user(self):
+        response = self.fetch("/twitter/client/show_user?name=somebody")
+        response.rethrow()
+        self.assertEqual(
+            json_decode(response.body), {"name": "Somebody", "screen_name": "somebody"}
+        )
+
+    def test_twitter_show_user_error(self):
+        response = self.fetch("/twitter/client/show_user?name=error")
+        self.assertEqual(response.code, 500)
+        self.assertEqual(response.body, b"error from twitter request")
+
+
+class GoogleLoginHandler(RequestHandler, GoogleOAuth2Mixin):
+    def initialize(self, test):
+        self.test = test
+        self._OAUTH_REDIRECT_URI = test.get_url("/client/login")
+        self._OAUTH_AUTHORIZE_URL = test.get_url("/google/oauth2/authorize")
+        self._OAUTH_ACCESS_TOKEN_URL = test.get_url("/google/oauth2/token")
+
+    @gen.coroutine
+    def get(self):
+        code = self.get_argument("code", None)
+        if code is not None:
+            # retrieve authenticate google user
+            access = yield self.get_authenticated_user(self._OAUTH_REDIRECT_URI, code)
+            user = yield self.oauth2_request(
+                self.test.get_url("/google/oauth2/userinfo"),
+                access_token=access["access_token"],
+            )
+            # return the user and access token as json
+            user["access_token"] = access["access_token"]
+            self.write(user)
+        else:
+            self.authorize_redirect(
+                redirect_uri=self._OAUTH_REDIRECT_URI,
+                client_id=self.settings["google_oauth"]["key"],
+                client_secret=self.settings["google_oauth"]["secret"],
+                scope=["profile", "email"],
+                response_type="code",
+                extra_params={"prompt": "select_account"},
+            )
+
+
+class GoogleOAuth2AuthorizeHandler(RequestHandler):
+    def get(self):
+        # issue a fake auth code and redirect to redirect_uri
+        code = "fake-authorization-code"
+        self.redirect(url_concat(self.get_argument("redirect_uri"), dict(code=code)))
+
+
+class GoogleOAuth2TokenHandler(RequestHandler):
+    def post(self):
+        assert self.get_argument("code") == "fake-authorization-code"
+        # issue a fake token
+        self.finish(
+            {"access_token": "fake-access-token", "expires_in": "never-expires"}
+        )
+
+
+class GoogleOAuth2UserinfoHandler(RequestHandler):
+    def get(self):
+        assert self.get_argument("access_token") == "fake-access-token"
+        # return a fake user
+        self.finish({"name": "Foo", "email": "foo@example.com"})
+
+
+class GoogleOAuth2Test(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application(
+            [
+                # test endpoints
+                ("/client/login", GoogleLoginHandler, dict(test=self)),
+                # simulated google authorization server endpoints
+                ("/google/oauth2/authorize", GoogleOAuth2AuthorizeHandler),
+                ("/google/oauth2/token", GoogleOAuth2TokenHandler),
+                ("/google/oauth2/userinfo", GoogleOAuth2UserinfoHandler),
+            ],
+            google_oauth={
+                "key": "fake_google_client_id",
+                "secret": "fake_google_client_secret",
+            },
+        )
+
+    def test_google_login(self):
+        response = self.fetch("/client/login")
+        self.assertDictEqual(
+            {
+                "name": "Foo",
+                "email": "foo@example.com",
+                "access_token": "fake-access-token",
+            },
+            json_decode(response.body),
+        )
diff --git a/venv/lib/python3.9/site-packages/tornado/test/autoreload_test.py b/venv/lib/python3.9/site-packages/tornado/test/autoreload_test.py
new file mode 100644
index 00000000..be481e10
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/autoreload_test.py
@@ -0,0 +1,127 @@
+import os
+import shutil
+import subprocess
+from subprocess import Popen
+import sys
+from tempfile import mkdtemp
+import time
+import unittest
+
+
+class AutoreloadTest(unittest.TestCase):
+    def setUp(self):
+        self.path = mkdtemp()
+
+    def tearDown(self):
+        try:
+            shutil.rmtree(self.path)
+        except OSError:
+            # Windows disallows deleting files that are in use by
+            # another process, and even though we've waited for our
+            # child process below, it appears that its lock on these
+            # files is not guaranteed to be released by this point.
+            # Sleep and try again (once).
+            time.sleep(1)
+            shutil.rmtree(self.path)
+
+    def test_reload_module(self):
+        main = """\
+import os
+import sys
+
+from tornado import autoreload
+
+# This import will fail if path is not set up correctly
+import testapp
+
+print('Starting')
+if 'TESTAPP_STARTED' not in os.environ:
+    os.environ['TESTAPP_STARTED'] = '1'
+    sys.stdout.flush()
+    autoreload._reload()
+"""
+
+        # Create temporary test application
+        os.mkdir(os.path.join(self.path, "testapp"))
+        open(os.path.join(self.path, "testapp/__init__.py"), "w").close()
+        with open(os.path.join(self.path, "testapp/__main__.py"), "w") as f:
+            f.write(main)
+
+        # Make sure the tornado module under test is available to the test
+        # application
+        pythonpath = os.getcwd()
+        if "PYTHONPATH" in os.environ:
+            pythonpath += os.pathsep + os.environ["PYTHONPATH"]
+
+        p = Popen(
+            [sys.executable, "-m", "testapp"],
+            stdout=subprocess.PIPE,
+            cwd=self.path,
+            env=dict(os.environ, PYTHONPATH=pythonpath),
+            universal_newlines=True,
+        )
+        out = p.communicate()[0]
+        self.assertEqual(out, "Starting\nStarting\n")
+
+    def test_reload_wrapper_preservation(self):
+        # This test verifies that when `python -m tornado.autoreload`
+        # is used on an application that also has an internal
+        # autoreload, the reload wrapper is preserved on restart.
+        main = """\
+import os
+import sys
+
+# This import will fail if path is not set up correctly
+import testapp
+
+if 'tornado.autoreload' not in sys.modules:
+    raise Exception('started without autoreload wrapper')
+
+import tornado.autoreload
+
+print('Starting')
+sys.stdout.flush()
+if 'TESTAPP_STARTED' not in os.environ:
+    os.environ['TESTAPP_STARTED'] = '1'
+    # Simulate an internal autoreload (one not caused
+    # by the wrapper).
+    tornado.autoreload._reload()
+else:
+    # Exit directly so autoreload doesn't catch it.
+    os._exit(0)
+"""
+
+        # Create temporary test application
+        os.mkdir(os.path.join(self.path, "testapp"))
+        init_file = os.path.join(self.path, "testapp", "__init__.py")
+        open(init_file, "w").close()
+        main_file = os.path.join(self.path, "testapp", "__main__.py")
+        with open(main_file, "w") as f:
+            f.write(main)
+
+        # Make sure the tornado module under test is available to the test
+        # application
+        pythonpath = os.getcwd()
+        if "PYTHONPATH" in os.environ:
+            pythonpath += os.pathsep + os.environ["PYTHONPATH"]
+
+        autoreload_proc = Popen(
+            [sys.executable, "-m", "tornado.autoreload", "-m", "testapp"],
+            stdout=subprocess.PIPE,
+            cwd=self.path,
+            env=dict(os.environ, PYTHONPATH=pythonpath),
+            universal_newlines=True,
+        )
+
+        # This timeout needs to be fairly generous for pypy due to jit
+        # warmup costs.
+        for i in range(40):
+            if autoreload_proc.poll() is not None:
+                break
+            time.sleep(0.1)
+        else:
+            autoreload_proc.kill()
+            raise Exception("subprocess failed to terminate")
+
+        out = autoreload_proc.communicate()[0]
+        self.assertEqual(out, "Starting\n" * 2)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/concurrent_test.py b/venv/lib/python3.9/site-packages/tornado/test/concurrent_test.py
new file mode 100644
index 00000000..33fcb650
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/concurrent_test.py
@@ -0,0 +1,212 @@
+#
+# Copyright 2012 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+from concurrent import futures
+import logging
+import re
+import socket
+import typing
+import unittest
+
+from tornado.concurrent import (
+    Future,
+    run_on_executor,
+    future_set_result_unless_cancelled,
+)
+from tornado.escape import utf8, to_unicode
+from tornado import gen
+from tornado.iostream import IOStream
+from tornado.tcpserver import TCPServer
+from tornado.testing import AsyncTestCase, bind_unused_port, gen_test
+
+
+class MiscFutureTest(AsyncTestCase):
+    def test_future_set_result_unless_cancelled(self):
+        fut = Future()  # type: Future[int]
+        future_set_result_unless_cancelled(fut, 42)
+        self.assertEqual(fut.result(), 42)
+        self.assertFalse(fut.cancelled())
+
+        fut = Future()
+        fut.cancel()
+        is_cancelled = fut.cancelled()
+        future_set_result_unless_cancelled(fut, 42)
+        self.assertEqual(fut.cancelled(), is_cancelled)
+        if not is_cancelled:
+            self.assertEqual(fut.result(), 42)
+
+
+# The following series of classes demonstrate and test various styles
+# of use, with and without generators and futures.
+
+
+class CapServer(TCPServer):
+    @gen.coroutine
+    def handle_stream(self, stream, address):
+        data = yield stream.read_until(b"\n")
+        data = to_unicode(data)
+        if data == data.upper():
+            stream.write(b"error\talready capitalized\n")
+        else:
+            # data already has \n
+            stream.write(utf8("ok\t%s" % data.upper()))
+        stream.close()
+
+
+class CapError(Exception):
+    pass
+
+
+class BaseCapClient(object):
+    def __init__(self, port):
+        self.port = port
+
+    def process_response(self, data):
+        m = re.match("(.*)\t(.*)\n", to_unicode(data))
+        if m is None:
+            raise Exception("did not match")
+        status, message = m.groups()
+        if status == "ok":
+            return message
+        else:
+            raise CapError(message)
+
+
+class GeneratorCapClient(BaseCapClient):
+    @gen.coroutine
+    def capitalize(self, request_data):
+        logging.debug("capitalize")
+        stream = IOStream(socket.socket())
+        logging.debug("connecting")
+        yield stream.connect(("127.0.0.1", self.port))
+        stream.write(utf8(request_data + "\n"))
+        logging.debug("reading")
+        data = yield stream.read_until(b"\n")
+        logging.debug("returning")
+        stream.close()
+        raise gen.Return(self.process_response(data))
+
+
+class ClientTestMixin(object):
+    client_class = None  # type: typing.Callable
+
+    def setUp(self):
+        super().setUp()  # type: ignore
+        self.server = CapServer()
+        sock, port = bind_unused_port()
+        self.server.add_sockets([sock])
+        self.client = self.client_class(port=port)
+
+    def tearDown(self):
+        self.server.stop()
+        super().tearDown()  # type: ignore
+
+    def test_future(self: typing.Any):
+        future = self.client.capitalize("hello")
+        self.io_loop.add_future(future, self.stop)
+        self.wait()
+        self.assertEqual(future.result(), "HELLO")
+
+    def test_future_error(self: typing.Any):
+        future = self.client.capitalize("HELLO")
+        self.io_loop.add_future(future, self.stop)
+        self.wait()
+        self.assertRaisesRegex(CapError, "already capitalized", future.result)  # type: ignore
+
+    def test_generator(self: typing.Any):
+        @gen.coroutine
+        def f():
+            result = yield self.client.capitalize("hello")
+            self.assertEqual(result, "HELLO")
+
+        self.io_loop.run_sync(f)
+
+    def test_generator_error(self: typing.Any):
+        @gen.coroutine
+        def f():
+            with self.assertRaisesRegex(CapError, "already capitalized"):
+                yield self.client.capitalize("HELLO")
+
+        self.io_loop.run_sync(f)
+
+
+class GeneratorClientTest(ClientTestMixin, AsyncTestCase):
+    client_class = GeneratorCapClient
+
+
+class RunOnExecutorTest(AsyncTestCase):
+    @gen_test
+    def test_no_calling(self):
+        class Object(object):
+            def __init__(self):
+                self.executor = futures.thread.ThreadPoolExecutor(1)
+
+            @run_on_executor
+            def f(self):
+                return 42
+
+        o = Object()
+        answer = yield o.f()
+        self.assertEqual(answer, 42)
+
+    @gen_test
+    def test_call_with_no_args(self):
+        class Object(object):
+            def __init__(self):
+                self.executor = futures.thread.ThreadPoolExecutor(1)
+
+            @run_on_executor()
+            def f(self):
+                return 42
+
+        o = Object()
+        answer = yield o.f()
+        self.assertEqual(answer, 42)
+
+    @gen_test
+    def test_call_with_executor(self):
+        class Object(object):
+            def __init__(self):
+                self.__executor = futures.thread.ThreadPoolExecutor(1)
+
+            @run_on_executor(executor="_Object__executor")
+            def f(self):
+                return 42
+
+        o = Object()
+        answer = yield o.f()
+        self.assertEqual(answer, 42)
+
+    @gen_test
+    def test_async_await(self):
+        class Object(object):
+            def __init__(self):
+                self.executor = futures.thread.ThreadPoolExecutor(1)
+
+            @run_on_executor()
+            def f(self):
+                return 42
+
+        o = Object()
+
+        async def f():
+            answer = await o.f()
+            return answer
+
+        result = yield f()
+        self.assertEqual(result, 42)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/csv_translations/fr_FR.csv b/venv/lib/python3.9/site-packages/tornado/test/csv_translations/fr_FR.csv
new file mode 100644
index 00000000..6321b6e7
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/csv_translations/fr_FR.csv
@@ -0,0 +1 @@
+"school","école"
diff --git a/venv/lib/python3.9/site-packages/tornado/test/curl_httpclient_test.py b/venv/lib/python3.9/site-packages/tornado/test/curl_httpclient_test.py
new file mode 100644
index 00000000..99af2933
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/curl_httpclient_test.py
@@ -0,0 +1,129 @@
+from hashlib import md5
+import unittest
+
+from tornado.escape import utf8
+from tornado.testing import AsyncHTTPTestCase
+from tornado.test import httpclient_test
+from tornado.web import Application, RequestHandler
+
+
+try:
+    import pycurl
+except ImportError:
+    pycurl = None  # type: ignore
+
+if pycurl is not None:
+    from tornado.curl_httpclient import CurlAsyncHTTPClient
+
+
+@unittest.skipIf(pycurl is None, "pycurl module not present")
+class CurlHTTPClientCommonTestCase(httpclient_test.HTTPClientCommonTestCase):
+    def get_http_client(self):
+        client = CurlAsyncHTTPClient(defaults=dict(allow_ipv6=False))
+        # make sure AsyncHTTPClient magic doesn't give us the wrong class
+        self.assertTrue(isinstance(client, CurlAsyncHTTPClient))
+        return client
+
+
+class DigestAuthHandler(RequestHandler):
+    def initialize(self, username, password):
+        self.username = username
+        self.password = password
+
+    def get(self):
+        realm = "test"
+        opaque = "asdf"
+        # Real implementations would use a random nonce.
+        nonce = "1234"
+
+        auth_header = self.request.headers.get("Authorization", None)
+        if auth_header is not None:
+            auth_mode, params = auth_header.split(" ", 1)
+            assert auth_mode == "Digest"
+            param_dict = {}
+            for pair in params.split(","):
+                k, v = pair.strip().split("=", 1)
+                if v[0] == '"' and v[-1] == '"':
+                    v = v[1:-1]
+                param_dict[k] = v
+            assert param_dict["realm"] == realm
+            assert param_dict["opaque"] == opaque
+            assert param_dict["nonce"] == nonce
+            assert param_dict["username"] == self.username
+            assert param_dict["uri"] == self.request.path
+            h1 = md5(
+                utf8("%s:%s:%s" % (self.username, realm, self.password))
+            ).hexdigest()
+            h2 = md5(
+                utf8("%s:%s" % (self.request.method, self.request.path))
+            ).hexdigest()
+            digest = md5(utf8("%s:%s:%s" % (h1, nonce, h2))).hexdigest()
+            if digest == param_dict["response"]:
+                self.write("ok")
+            else:
+                self.write("fail")
+        else:
+            self.set_status(401)
+            self.set_header(
+                "WWW-Authenticate",
+                'Digest realm="%s", nonce="%s", opaque="%s"' % (realm, nonce, opaque),
+            )
+
+
+class CustomReasonHandler(RequestHandler):
+    def get(self):
+        self.set_status(200, "Custom reason")
+
+
+class CustomFailReasonHandler(RequestHandler):
+    def get(self):
+        self.set_status(400, "Custom reason")
+
+
+@unittest.skipIf(pycurl is None, "pycurl module not present")
+class CurlHTTPClientTestCase(AsyncHTTPTestCase):
+    def setUp(self):
+        super().setUp()
+        self.http_client = self.create_client()
+
+    def get_app(self):
+        return Application(
+            [
+                ("/digest", DigestAuthHandler, {"username": "foo", "password": "bar"}),
+                (
+                    "/digest_non_ascii",
+                    DigestAuthHandler,
+                    {"username": "foo", "password": "barユ£"},
+                ),
+                ("/custom_reason", CustomReasonHandler),
+                ("/custom_fail_reason", CustomFailReasonHandler),
+            ]
+        )
+
+    def create_client(self, **kwargs):
+        return CurlAsyncHTTPClient(
+            force_instance=True, defaults=dict(allow_ipv6=False), **kwargs
+        )
+
+    def test_digest_auth(self):
+        response = self.fetch(
+            "/digest", auth_mode="digest", auth_username="foo", auth_password="bar"
+        )
+        self.assertEqual(response.body, b"ok")
+
+    def test_custom_reason(self):
+        response = self.fetch("/custom_reason")
+        self.assertEqual(response.reason, "Custom reason")
+
+    def test_fail_custom_reason(self):
+        response = self.fetch("/custom_fail_reason")
+        self.assertEqual(str(response.error), "HTTP 400: Custom reason")
+
+    def test_digest_auth_non_ascii(self):
+        response = self.fetch(
+            "/digest_non_ascii",
+            auth_mode="digest",
+            auth_username="foo",
+            auth_password="barユ£",
+        )
+        self.assertEqual(response.body, b"ok")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/escape_test.py b/venv/lib/python3.9/site-packages/tornado/test/escape_test.py
new file mode 100644
index 00000000..a90d11d6
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/escape_test.py
@@ -0,0 +1,322 @@
+import unittest
+
+import tornado
+from tornado.escape import (
+    utf8,
+    xhtml_escape,
+    xhtml_unescape,
+    url_escape,
+    url_unescape,
+    to_unicode,
+    json_decode,
+    json_encode,
+    squeeze,
+    recursive_unicode,
+)
+from tornado.util import unicode_type
+
+from typing import List, Tuple, Union, Dict, Any  # noqa: F401
+
+linkify_tests = [
+    # (input, linkify_kwargs, expected_output)
+    (
+        "hello http://world.com/!",
+        {},
+        'hello <a href="http://world.com/">http://world.com/</a>!',
+    ),
+    (
+        "hello http://world.com/with?param=true&stuff=yes",
+        {},
+        'hello <a href="http://world.com/with?param=true&amp;stuff=yes">http://world.com/with?param=true&amp;stuff=yes</a>',  # noqa: E501
+    ),
+    # an opened paren followed by many chars killed Gruber's regex
+    (
+        "http://url.com/w(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+        {},
+        '<a href="http://url.com/w">http://url.com/w</a>(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',  # noqa: E501
+    ),
+    # as did too many dots at the end
+    (
+        "http://url.com/withmany.......................................",
+        {},
+        '<a href="http://url.com/withmany">http://url.com/withmany</a>.......................................',  # noqa: E501
+    ),
+    (
+        "http://url.com/withmany((((((((((((((((((((((((((((((((((a)",
+        {},
+        '<a href="http://url.com/withmany">http://url.com/withmany</a>((((((((((((((((((((((((((((((((((a)',  # noqa: E501
+    ),
+    # some examples from http://daringfireball.net/2009/11/liberal_regex_for_matching_urls
+    # plus a fex extras (such as multiple parentheses).
+    (
+        "http://foo.com/blah_blah",
+        {},
+        '<a href="http://foo.com/blah_blah">http://foo.com/blah_blah</a>',
+    ),
+    (
+        "http://foo.com/blah_blah/",
+        {},
+        '<a href="http://foo.com/blah_blah/">http://foo.com/blah_blah/</a>',
+    ),
+    (
+        "(Something like http://foo.com/blah_blah)",
+        {},
+        '(Something like <a href="http://foo.com/blah_blah">http://foo.com/blah_blah</a>)',
+    ),
+    (
+        "http://foo.com/blah_blah_(wikipedia)",
+        {},
+        '<a href="http://foo.com/blah_blah_(wikipedia)">http://foo.com/blah_blah_(wikipedia)</a>',
+    ),
+    (
+        "http://foo.com/blah_(blah)_(wikipedia)_blah",
+        {},
+        '<a href="http://foo.com/blah_(blah)_(wikipedia)_blah">http://foo.com/blah_(blah)_(wikipedia)_blah</a>',  # noqa: E501
+    ),
+    (
+        "(Something like http://foo.com/blah_blah_(wikipedia))",
+        {},
+        '(Something like <a href="http://foo.com/blah_blah_(wikipedia)">http://foo.com/blah_blah_(wikipedia)</a>)',  # noqa: E501
+    ),
+    (
+        "http://foo.com/blah_blah.",
+        {},
+        '<a href="http://foo.com/blah_blah">http://foo.com/blah_blah</a>.',
+    ),
+    (
+        "http://foo.com/blah_blah/.",
+        {},
+        '<a href="http://foo.com/blah_blah/">http://foo.com/blah_blah/</a>.',
+    ),
+    (
+        "<http://foo.com/blah_blah>",
+        {},
+        '&lt;<a href="http://foo.com/blah_blah">http://foo.com/blah_blah</a>&gt;',
+    ),
+    (
+        "<http://foo.com/blah_blah/>",
+        {},
+        '&lt;<a href="http://foo.com/blah_blah/">http://foo.com/blah_blah/</a>&gt;',
+    ),
+    (
+        "http://foo.com/blah_blah,",
+        {},
+        '<a href="http://foo.com/blah_blah">http://foo.com/blah_blah</a>,',
+    ),
+    (
+        "http://www.example.com/wpstyle/?p=364.",
+        {},
+        '<a href="http://www.example.com/wpstyle/?p=364">http://www.example.com/wpstyle/?p=364</a>.',  # noqa: E501
+    ),
+    (
+        "rdar://1234",
+        {"permitted_protocols": ["http", "rdar"]},
+        '<a href="rdar://1234">rdar://1234</a>',
+    ),
+    (
+        "rdar:/1234",
+        {"permitted_protocols": ["rdar"]},
+        '<a href="rdar:/1234">rdar:/1234</a>',
+    ),
+    (
+        "http://userid:password@example.com:8080",
+        {},
+        '<a href="http://userid:password@example.com:8080">http://userid:password@example.com:8080</a>',  # noqa: E501
+    ),
+    (
+        "http://userid@example.com",
+        {},
+        '<a href="http://userid@example.com">http://userid@example.com</a>',
+    ),
+    (
+        "http://userid@example.com:8080",
+        {},
+        '<a href="http://userid@example.com:8080">http://userid@example.com:8080</a>',
+    ),
+    (
+        "http://userid:password@example.com",
+        {},
+        '<a href="http://userid:password@example.com">http://userid:password@example.com</a>',
+    ),
+    (
+        "message://%3c330e7f8409726r6a4ba78dkf1fd71420c1bf6ff@mail.gmail.com%3e",
+        {"permitted_protocols": ["http", "message"]},
+        '<a href="message://%3c330e7f8409726r6a4ba78dkf1fd71420c1bf6ff@mail.gmail.com%3e">'
+        "message://%3c330e7f8409726r6a4ba78dkf1fd71420c1bf6ff@mail.gmail.com%3e</a>",
+    ),
+    (
+        "http://\u27a1.ws/\u4a39",
+        {},
+        '<a href="http://\u27a1.ws/\u4a39">http://\u27a1.ws/\u4a39</a>',
+    ),
+    (
+        "<tag>http://example.com</tag>",
+        {},
+        '&lt;tag&gt;<a href="http://example.com">http://example.com</a>&lt;/tag&gt;',
+    ),
+    (
+        "Just a www.example.com link.",
+        {},
+        'Just a <a href="http://www.example.com">www.example.com</a> link.',
+    ),
+    (
+        "Just a www.example.com link.",
+        {"require_protocol": True},
+        "Just a www.example.com link.",
+    ),
+    (
+        "A http://reallylong.com/link/that/exceedsthelenglimit.html",
+        {"require_protocol": True, "shorten": True},
+        'A <a href="http://reallylong.com/link/that/exceedsthelenglimit.html"'
+        ' title="http://reallylong.com/link/that/exceedsthelenglimit.html">http://reallylong.com/link...</a>',  # noqa: E501
+    ),
+    (
+        "A http://reallylongdomainnamethatwillbetoolong.com/hi!",
+        {"shorten": True},
+        'A <a href="http://reallylongdomainnamethatwillbetoolong.com/hi"'
+        ' title="http://reallylongdomainnamethatwillbetoolong.com/hi">http://reallylongdomainnametha...</a>!',  # noqa: E501
+    ),
+    (
+        "A file:///passwords.txt and http://web.com link",
+        {},
+        'A file:///passwords.txt and <a href="http://web.com">http://web.com</a> link',
+    ),
+    (
+        "A file:///passwords.txt and http://web.com link",
+        {"permitted_protocols": ["file"]},
+        'A <a href="file:///passwords.txt">file:///passwords.txt</a> and http://web.com link',
+    ),
+    (
+        "www.external-link.com",
+        {"extra_params": 'rel="nofollow" class="external"'},
+        '<a href="http://www.external-link.com" rel="nofollow" class="external">www.external-link.com</a>',  # noqa: E501
+    ),
+    (
+        "www.external-link.com and www.internal-link.com/blogs extra",
+        {
+            "extra_params": lambda href: 'class="internal"'
+            if href.startswith("http://www.internal-link.com")
+            else 'rel="nofollow" class="external"'
+        },
+        '<a href="http://www.external-link.com" rel="nofollow" class="external">www.external-link.com</a>'  # noqa: E501
+        ' and <a href="http://www.internal-link.com/blogs" class="internal">www.internal-link.com/blogs</a> extra',  # noqa: E501
+    ),
+    (
+        "www.external-link.com",
+        {"extra_params": lambda href: '    rel="nofollow" class="external"  '},
+        '<a href="http://www.external-link.com" rel="nofollow" class="external">www.external-link.com</a>',  # noqa: E501
+    ),
+]  # type: List[Tuple[Union[str, bytes], Dict[str, Any], str]]
+
+
+class EscapeTestCase(unittest.TestCase):
+    def test_linkify(self):
+        for text, kwargs, html in linkify_tests:
+            linked = tornado.escape.linkify(text, **kwargs)
+            self.assertEqual(linked, html)
+
+    def test_xhtml_escape(self):
+        tests = [
+            ("<foo>", "&lt;foo&gt;"),
+            ("<foo>", "&lt;foo&gt;"),
+            (b"<foo>", b"&lt;foo&gt;"),
+            ("<>&\"'", "&lt;&gt;&amp;&quot;&#39;"),
+            ("&amp;", "&amp;amp;"),
+            ("<\u00e9>", "&lt;\u00e9&gt;"),
+            (b"<\xc3\xa9>", b"&lt;\xc3\xa9&gt;"),
+        ]  # type: List[Tuple[Union[str, bytes], Union[str, bytes]]]
+        for unescaped, escaped in tests:
+            self.assertEqual(utf8(xhtml_escape(unescaped)), utf8(escaped))
+            self.assertEqual(utf8(unescaped), utf8(xhtml_unescape(escaped)))
+
+    def test_xhtml_unescape_numeric(self):
+        tests = [
+            ("foo&#32;bar", "foo bar"),
+            ("foo&#x20;bar", "foo bar"),
+            ("foo&#X20;bar", "foo bar"),
+            ("foo&#xabc;bar", "foo\u0abcbar"),
+            ("foo&#xyz;bar", "foo&#xyz;bar"),  # invalid encoding
+            ("foo&#;bar", "foo&#;bar"),  # invalid encoding
+            ("foo&#x;bar", "foo&#x;bar"),  # invalid encoding
+        ]
+        for escaped, unescaped in tests:
+            self.assertEqual(unescaped, xhtml_unescape(escaped))
+
+    def test_url_escape_unicode(self):
+        tests = [
+            # byte strings are passed through as-is
+            ("\u00e9".encode("utf8"), "%C3%A9"),
+            ("\u00e9".encode("latin1"), "%E9"),
+            # unicode strings become utf8
+            ("\u00e9", "%C3%A9"),
+        ]  # type: List[Tuple[Union[str, bytes], str]]
+        for unescaped, escaped in tests:
+            self.assertEqual(url_escape(unescaped), escaped)
+
+    def test_url_unescape_unicode(self):
+        tests = [
+            ("%C3%A9", "\u00e9", "utf8"),
+            ("%C3%A9", "\u00c3\u00a9", "latin1"),
+            ("%C3%A9", utf8("\u00e9"), None),
+        ]
+        for escaped, unescaped, encoding in tests:
+            # input strings to url_unescape should only contain ascii
+            # characters, but make sure the function accepts both byte
+            # and unicode strings.
+            self.assertEqual(url_unescape(to_unicode(escaped), encoding), unescaped)
+            self.assertEqual(url_unescape(utf8(escaped), encoding), unescaped)
+
+    def test_url_escape_quote_plus(self):
+        unescaped = "+ #%"
+        plus_escaped = "%2B+%23%25"
+        escaped = "%2B%20%23%25"
+        self.assertEqual(url_escape(unescaped), plus_escaped)
+        self.assertEqual(url_escape(unescaped, plus=False), escaped)
+        self.assertEqual(url_unescape(plus_escaped), unescaped)
+        self.assertEqual(url_unescape(escaped, plus=False), unescaped)
+        self.assertEqual(url_unescape(plus_escaped, encoding=None), utf8(unescaped))
+        self.assertEqual(
+            url_unescape(escaped, encoding=None, plus=False), utf8(unescaped)
+        )
+
+    def test_escape_return_types(self):
+        # On python2 the escape methods should generally return the same
+        # type as their argument
+        self.assertEqual(type(xhtml_escape("foo")), str)
+        self.assertEqual(type(xhtml_escape("foo")), unicode_type)
+
+    def test_json_decode(self):
+        # json_decode accepts both bytes and unicode, but strings it returns
+        # are always unicode.
+        self.assertEqual(json_decode(b'"foo"'), "foo")
+        self.assertEqual(json_decode('"foo"'), "foo")
+
+        # Non-ascii bytes are interpreted as utf8
+        self.assertEqual(json_decode(utf8('"\u00e9"')), "\u00e9")
+
+    def test_json_encode(self):
+        # json deals with strings, not bytes.  On python 2 byte strings will
+        # convert automatically if they are utf8; on python 3 byte strings
+        # are not allowed.
+        self.assertEqual(json_decode(json_encode("\u00e9")), "\u00e9")
+        if bytes is str:
+            self.assertEqual(json_decode(json_encode(utf8("\u00e9"))), "\u00e9")
+            self.assertRaises(UnicodeDecodeError, json_encode, b"\xe9")
+
+    def test_squeeze(self):
+        self.assertEqual(
+            squeeze("sequences     of    whitespace   chars"),
+            "sequences of whitespace chars",
+        )
+
+    def test_recursive_unicode(self):
+        tests = {
+            "dict": {b"foo": b"bar"},
+            "list": [b"foo", b"bar"],
+            "tuple": (b"foo", b"bar"),
+            "bytes": b"foo",
+        }
+        self.assertEqual(recursive_unicode(tests["dict"]), {"foo": "bar"})
+        self.assertEqual(recursive_unicode(tests["list"]), ["foo", "bar"])
+        self.assertEqual(recursive_unicode(tests["tuple"]), ("foo", "bar"))
+        self.assertEqual(recursive_unicode(tests["bytes"]), "foo")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/gen_test.py b/venv/lib/python3.9/site-packages/tornado/test/gen_test.py
new file mode 100644
index 00000000..c17bf65f
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/gen_test.py
@@ -0,0 +1,1129 @@
+import asyncio
+from concurrent import futures
+import gc
+import datetime
+import platform
+import sys
+import time
+import weakref
+import unittest
+
+from tornado.concurrent import Future
+from tornado.log import app_log
+from tornado.testing import AsyncHTTPTestCase, AsyncTestCase, ExpectLog, gen_test
+from tornado.test.util import skipOnTravis, skipNotCPython
+from tornado.web import Application, RequestHandler, HTTPError
+
+from tornado import gen
+
+try:
+    import contextvars
+except ImportError:
+    contextvars = None  # type: ignore
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import List, Optional  # noqa: F401
+
+
+class GenBasicTest(AsyncTestCase):
+    @gen.coroutine
+    def delay(self, iterations, arg):
+        """Returns arg after a number of IOLoop iterations."""
+        for i in range(iterations):
+            yield gen.moment
+        raise gen.Return(arg)
+
+    @gen.coroutine
+    def async_future(self, result):
+        yield gen.moment
+        return result
+
+    @gen.coroutine
+    def async_exception(self, e):
+        yield gen.moment
+        raise e
+
+    @gen.coroutine
+    def add_one_async(self, x):
+        yield gen.moment
+        raise gen.Return(x + 1)
+
+    def test_no_yield(self):
+        @gen.coroutine
+        def f():
+            pass
+
+        self.io_loop.run_sync(f)
+
+    def test_exception_phase1(self):
+        @gen.coroutine
+        def f():
+            1 / 0
+
+        self.assertRaises(ZeroDivisionError, self.io_loop.run_sync, f)
+
+    def test_exception_phase2(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            1 / 0
+
+        self.assertRaises(ZeroDivisionError, self.io_loop.run_sync, f)
+
+    def test_bogus_yield(self):
+        @gen.coroutine
+        def f():
+            yield 42
+
+        self.assertRaises(gen.BadYieldError, self.io_loop.run_sync, f)
+
+    def test_bogus_yield_tuple(self):
+        @gen.coroutine
+        def f():
+            yield (1, 2)
+
+        self.assertRaises(gen.BadYieldError, self.io_loop.run_sync, f)
+
+    def test_reuse(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+
+        self.io_loop.run_sync(f)
+        self.io_loop.run_sync(f)
+
+    def test_none(self):
+        @gen.coroutine
+        def f():
+            yield None
+
+        self.io_loop.run_sync(f)
+
+    def test_multi(self):
+        @gen.coroutine
+        def f():
+            results = yield [self.add_one_async(1), self.add_one_async(2)]
+            self.assertEqual(results, [2, 3])
+
+        self.io_loop.run_sync(f)
+
+    def test_multi_dict(self):
+        @gen.coroutine
+        def f():
+            results = yield dict(foo=self.add_one_async(1), bar=self.add_one_async(2))
+            self.assertEqual(results, dict(foo=2, bar=3))
+
+        self.io_loop.run_sync(f)
+
+    def test_multi_delayed(self):
+        @gen.coroutine
+        def f():
+            # callbacks run at different times
+            responses = yield gen.multi_future(
+                [self.delay(3, "v1"), self.delay(1, "v2")]
+            )
+            self.assertEqual(responses, ["v1", "v2"])
+
+        self.io_loop.run_sync(f)
+
+    def test_multi_dict_delayed(self):
+        @gen.coroutine
+        def f():
+            # callbacks run at different times
+            responses = yield gen.multi_future(
+                dict(foo=self.delay(3, "v1"), bar=self.delay(1, "v2"))
+            )
+            self.assertEqual(responses, dict(foo="v1", bar="v2"))
+
+        self.io_loop.run_sync(f)
+
+    @skipOnTravis
+    @gen_test
+    def test_multi_performance(self):
+        # Yielding a list used to have quadratic performance; make
+        # sure a large list stays reasonable.  On my laptop a list of
+        # 2000 used to take 1.8s, now it takes 0.12.
+        start = time.time()
+        yield [gen.moment for i in range(2000)]
+        end = time.time()
+        self.assertLess(end - start, 1.0)
+
+    @gen_test
+    def test_multi_empty(self):
+        # Empty lists or dicts should return the same type.
+        x = yield []
+        self.assertTrue(isinstance(x, list))
+        y = yield {}
+        self.assertTrue(isinstance(y, dict))
+
+    @gen_test
+    def test_future(self):
+        result = yield self.async_future(1)
+        self.assertEqual(result, 1)
+
+    @gen_test
+    def test_multi_future(self):
+        results = yield [self.async_future(1), self.async_future(2)]
+        self.assertEqual(results, [1, 2])
+
+    @gen_test
+    def test_multi_future_duplicate(self):
+        # Note that this doesn't work with native corotines, only with
+        # decorated coroutines.
+        f = self.async_future(2)
+        results = yield [self.async_future(1), f, self.async_future(3), f]
+        self.assertEqual(results, [1, 2, 3, 2])
+
+    @gen_test
+    def test_multi_dict_future(self):
+        results = yield dict(foo=self.async_future(1), bar=self.async_future(2))
+        self.assertEqual(results, dict(foo=1, bar=2))
+
+    @gen_test
+    def test_multi_exceptions(self):
+        with ExpectLog(app_log, "Multiple exceptions in yield list"):
+            with self.assertRaises(RuntimeError) as cm:
+                yield gen.Multi(
+                    [
+                        self.async_exception(RuntimeError("error 1")),
+                        self.async_exception(RuntimeError("error 2")),
+                    ]
+                )
+        self.assertEqual(str(cm.exception), "error 1")
+
+        # With only one exception, no error is logged.
+        with self.assertRaises(RuntimeError):
+            yield gen.Multi(
+                [self.async_exception(RuntimeError("error 1")), self.async_future(2)]
+            )
+
+        # Exception logging may be explicitly quieted.
+        with self.assertRaises(RuntimeError):
+            yield gen.Multi(
+                [
+                    self.async_exception(RuntimeError("error 1")),
+                    self.async_exception(RuntimeError("error 2")),
+                ],
+                quiet_exceptions=RuntimeError,
+            )
+
+    @gen_test
+    def test_multi_future_exceptions(self):
+        with ExpectLog(app_log, "Multiple exceptions in yield list"):
+            with self.assertRaises(RuntimeError) as cm:
+                yield [
+                    self.async_exception(RuntimeError("error 1")),
+                    self.async_exception(RuntimeError("error 2")),
+                ]
+        self.assertEqual(str(cm.exception), "error 1")
+
+        # With only one exception, no error is logged.
+        with self.assertRaises(RuntimeError):
+            yield [self.async_exception(RuntimeError("error 1")), self.async_future(2)]
+
+        # Exception logging may be explicitly quieted.
+        with self.assertRaises(RuntimeError):
+            yield gen.multi_future(
+                [
+                    self.async_exception(RuntimeError("error 1")),
+                    self.async_exception(RuntimeError("error 2")),
+                ],
+                quiet_exceptions=RuntimeError,
+            )
+
+    def test_sync_raise_return(self):
+        @gen.coroutine
+        def f():
+            raise gen.Return()
+
+        self.io_loop.run_sync(f)
+
+    def test_async_raise_return(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return()
+
+        self.io_loop.run_sync(f)
+
+    def test_sync_raise_return_value(self):
+        @gen.coroutine
+        def f():
+            raise gen.Return(42)
+
+        self.assertEqual(42, self.io_loop.run_sync(f))
+
+    def test_sync_raise_return_value_tuple(self):
+        @gen.coroutine
+        def f():
+            raise gen.Return((1, 2))
+
+        self.assertEqual((1, 2), self.io_loop.run_sync(f))
+
+    def test_async_raise_return_value(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return(42)
+
+        self.assertEqual(42, self.io_loop.run_sync(f))
+
+    def test_async_raise_return_value_tuple(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return((1, 2))
+
+        self.assertEqual((1, 2), self.io_loop.run_sync(f))
+
+
+class GenCoroutineTest(AsyncTestCase):
+    def setUp(self):
+        # Stray StopIteration exceptions can lead to tests exiting prematurely,
+        # so we need explicit checks here to make sure the tests run all
+        # the way through.
+        self.finished = False
+        super().setUp()
+
+    def tearDown(self):
+        super().tearDown()
+        assert self.finished
+
+    def test_attributes(self):
+        self.finished = True
+
+        def f():
+            yield gen.moment
+
+        coro = gen.coroutine(f)
+        self.assertEqual(coro.__name__, f.__name__)
+        self.assertEqual(coro.__module__, f.__module__)
+        self.assertIs(coro.__wrapped__, f)  # type: ignore
+
+    def test_is_coroutine_function(self):
+        self.finished = True
+
+        def f():
+            yield gen.moment
+
+        coro = gen.coroutine(f)
+        self.assertFalse(gen.is_coroutine_function(f))
+        self.assertTrue(gen.is_coroutine_function(coro))
+        self.assertFalse(gen.is_coroutine_function(coro()))
+
+    @gen_test
+    def test_sync_gen_return(self):
+        @gen.coroutine
+        def f():
+            raise gen.Return(42)
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_async_gen_return(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return(42)
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_sync_return(self):
+        @gen.coroutine
+        def f():
+            return 42
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_async_return(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            return 42
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_async_early_return(self):
+        # A yield statement exists but is not executed, which means
+        # this function "returns" via an exception.  This exception
+        # doesn't happen before the exception handling is set up.
+        @gen.coroutine
+        def f():
+            if True:
+                return 42
+            yield gen.Task(self.io_loop.add_callback)
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_async_await(self):
+        @gen.coroutine
+        def f1():
+            yield gen.moment
+            raise gen.Return(42)
+
+        # This test verifies that an async function can await a
+        # yield-based gen.coroutine, and that a gen.coroutine
+        # (the test method itself) can yield an async function.
+        async def f2():
+            result = await f1()
+            return result
+
+        result = yield f2()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_asyncio_sleep_zero(self):
+        # asyncio.sleep(0) turns into a special case (equivalent to
+        # `yield None`)
+        async def f():
+            import asyncio
+
+            await asyncio.sleep(0)
+            return 42
+
+        result = yield f()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_async_await_mixed_multi_native_future(self):
+        @gen.coroutine
+        def f1():
+            yield gen.moment
+
+        async def f2():
+            await f1()
+            return 42
+
+        @gen.coroutine
+        def f3():
+            yield gen.moment
+            raise gen.Return(43)
+
+        results = yield [f2(), f3()]
+        self.assertEqual(results, [42, 43])
+        self.finished = True
+
+    @gen_test
+    def test_async_with_timeout(self):
+        async def f1():
+            return 42
+
+        result = yield gen.with_timeout(datetime.timedelta(hours=1), f1())
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_sync_return_no_value(self):
+        @gen.coroutine
+        def f():
+            return
+
+        result = yield f()
+        self.assertEqual(result, None)
+        self.finished = True
+
+    @gen_test
+    def test_async_return_no_value(self):
+        # Without a return value we don't need python 3.3.
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            return
+
+        result = yield f()
+        self.assertEqual(result, None)
+        self.finished = True
+
+    @gen_test
+    def test_sync_raise(self):
+        @gen.coroutine
+        def f():
+            1 / 0
+
+        # The exception is raised when the future is yielded
+        # (or equivalently when its result method is called),
+        # not when the function itself is called).
+        future = f()
+        with self.assertRaises(ZeroDivisionError):
+            yield future
+        self.finished = True
+
+    @gen_test
+    def test_async_raise(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            1 / 0
+
+        future = f()
+        with self.assertRaises(ZeroDivisionError):
+            yield future
+        self.finished = True
+
+    @gen_test
+    def test_replace_yieldpoint_exception(self):
+        # Test exception handling: a coroutine can catch one exception
+        # raised by a yield point and raise a different one.
+        @gen.coroutine
+        def f1():
+            1 / 0
+
+        @gen.coroutine
+        def f2():
+            try:
+                yield f1()
+            except ZeroDivisionError:
+                raise KeyError()
+
+        future = f2()
+        with self.assertRaises(KeyError):
+            yield future
+        self.finished = True
+
+    @gen_test
+    def test_swallow_yieldpoint_exception(self):
+        # Test exception handling: a coroutine can catch an exception
+        # raised by a yield point and not raise a different one.
+        @gen.coroutine
+        def f1():
+            1 / 0
+
+        @gen.coroutine
+        def f2():
+            try:
+                yield f1()
+            except ZeroDivisionError:
+                raise gen.Return(42)
+
+        result = yield f2()
+        self.assertEqual(result, 42)
+        self.finished = True
+
+    @gen_test
+    def test_moment(self):
+        calls = []
+
+        @gen.coroutine
+        def f(name, yieldable):
+            for i in range(5):
+                calls.append(name)
+                yield yieldable
+
+        # First, confirm the behavior without moment: each coroutine
+        # monopolizes the event loop until it finishes.
+        immediate = Future()  # type: Future[None]
+        immediate.set_result(None)
+        yield [f("a", immediate), f("b", immediate)]
+        self.assertEqual("".join(calls), "aaaaabbbbb")
+
+        # With moment, they take turns.
+        calls = []
+        yield [f("a", gen.moment), f("b", gen.moment)]
+        self.assertEqual("".join(calls), "ababababab")
+        self.finished = True
+
+        calls = []
+        yield [f("a", gen.moment), f("b", immediate)]
+        self.assertEqual("".join(calls), "abbbbbaaaa")
+
+    @gen_test
+    def test_sleep(self):
+        yield gen.sleep(0.01)
+        self.finished = True
+
+    @gen_test
+    def test_py3_leak_exception_context(self):
+        class LeakedException(Exception):
+            pass
+
+        @gen.coroutine
+        def inner(iteration):
+            raise LeakedException(iteration)
+
+        try:
+            yield inner(1)
+        except LeakedException as e:
+            self.assertEqual(str(e), "1")
+            self.assertIsNone(e.__context__)
+
+        try:
+            yield inner(2)
+        except LeakedException as e:
+            self.assertEqual(str(e), "2")
+            self.assertIsNone(e.__context__)
+
+        self.finished = True
+
+    @skipNotCPython
+    @unittest.skipIf(
+        (3,) < sys.version_info < (3, 6), "asyncio.Future has reference cycles"
+    )
+    def test_coroutine_refcounting(self):
+        # On CPython, tasks and their arguments should be released immediately
+        # without waiting for garbage collection.
+        @gen.coroutine
+        def inner():
+            class Foo(object):
+                pass
+
+            local_var = Foo()
+            self.local_ref = weakref.ref(local_var)
+
+            def dummy():
+                pass
+
+            yield gen.coroutine(dummy)()
+            raise ValueError("Some error")
+
+        @gen.coroutine
+        def inner2():
+            try:
+                yield inner()
+            except ValueError:
+                pass
+
+        self.io_loop.run_sync(inner2, timeout=3)
+
+        self.assertIs(self.local_ref(), None)
+        self.finished = True
+
+    def test_asyncio_future_debug_info(self):
+        self.finished = True
+        # Enable debug mode
+        asyncio_loop = asyncio.get_event_loop()
+        self.addCleanup(asyncio_loop.set_debug, asyncio_loop.get_debug())
+        asyncio_loop.set_debug(True)
+
+        def f():
+            yield gen.moment
+
+        coro = gen.coroutine(f)()
+        self.assertIsInstance(coro, asyncio.Future)
+        # We expect the coroutine repr() to show the place where
+        # it was instantiated
+        expected = "created at %s:%d" % (__file__, f.__code__.co_firstlineno + 3)
+        actual = repr(coro)
+        self.assertIn(expected, actual)
+
+    @gen_test
+    def test_asyncio_gather(self):
+        # This demonstrates that tornado coroutines can be understood
+        # by asyncio (This failed prior to Tornado 5.0).
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return(1)
+
+        ret = yield asyncio.gather(f(), f())
+        self.assertEqual(ret, [1, 1])
+        self.finished = True
+
+
+class GenCoroutineSequenceHandler(RequestHandler):
+    @gen.coroutine
+    def get(self):
+        yield gen.moment
+        self.write("1")
+        yield gen.moment
+        self.write("2")
+        yield gen.moment
+        self.finish("3")
+
+
+class GenCoroutineUnfinishedSequenceHandler(RequestHandler):
+    @gen.coroutine
+    def get(self):
+        yield gen.moment
+        self.write("1")
+        yield gen.moment
+        self.write("2")
+        yield gen.moment
+        # just write, don't finish
+        self.write("3")
+
+
+# "Undecorated" here refers to the absence of @asynchronous.
+class UndecoratedCoroutinesHandler(RequestHandler):
+    @gen.coroutine
+    def prepare(self):
+        self.chunks = []  # type: List[str]
+        yield gen.moment
+        self.chunks.append("1")
+
+    @gen.coroutine
+    def get(self):
+        self.chunks.append("2")
+        yield gen.moment
+        self.chunks.append("3")
+        yield gen.moment
+        self.write("".join(self.chunks))
+
+
+class AsyncPrepareErrorHandler(RequestHandler):
+    @gen.coroutine
+    def prepare(self):
+        yield gen.moment
+        raise HTTPError(403)
+
+    def get(self):
+        self.finish("ok")
+
+
+class NativeCoroutineHandler(RequestHandler):
+    async def get(self):
+        await asyncio.sleep(0)
+        self.write("ok")
+
+
+class GenWebTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application(
+            [
+                ("/coroutine_sequence", GenCoroutineSequenceHandler),
+                (
+                    "/coroutine_unfinished_sequence",
+                    GenCoroutineUnfinishedSequenceHandler,
+                ),
+                ("/undecorated_coroutine", UndecoratedCoroutinesHandler),
+                ("/async_prepare_error", AsyncPrepareErrorHandler),
+                ("/native_coroutine", NativeCoroutineHandler),
+            ]
+        )
+
+    def test_coroutine_sequence_handler(self):
+        response = self.fetch("/coroutine_sequence")
+        self.assertEqual(response.body, b"123")
+
+    def test_coroutine_unfinished_sequence_handler(self):
+        response = self.fetch("/coroutine_unfinished_sequence")
+        self.assertEqual(response.body, b"123")
+
+    def test_undecorated_coroutines(self):
+        response = self.fetch("/undecorated_coroutine")
+        self.assertEqual(response.body, b"123")
+
+    def test_async_prepare_error_handler(self):
+        response = self.fetch("/async_prepare_error")
+        self.assertEqual(response.code, 403)
+
+    def test_native_coroutine_handler(self):
+        response = self.fetch("/native_coroutine")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.body, b"ok")
+
+
+class WithTimeoutTest(AsyncTestCase):
+    @gen_test
+    def test_timeout(self):
+        with self.assertRaises(gen.TimeoutError):
+            yield gen.with_timeout(datetime.timedelta(seconds=0.1), Future())
+
+    @gen_test
+    def test_completes_before_timeout(self):
+        future = Future()  # type: Future[str]
+        self.io_loop.add_timeout(
+            datetime.timedelta(seconds=0.1), lambda: future.set_result("asdf")
+        )
+        result = yield gen.with_timeout(datetime.timedelta(seconds=3600), future)
+        self.assertEqual(result, "asdf")
+
+    @gen_test
+    def test_fails_before_timeout(self):
+        future = Future()  # type: Future[str]
+        self.io_loop.add_timeout(
+            datetime.timedelta(seconds=0.1),
+            lambda: future.set_exception(ZeroDivisionError()),
+        )
+        with self.assertRaises(ZeroDivisionError):
+            yield gen.with_timeout(datetime.timedelta(seconds=3600), future)
+
+    @gen_test
+    def test_already_resolved(self):
+        future = Future()  # type: Future[str]
+        future.set_result("asdf")
+        result = yield gen.with_timeout(datetime.timedelta(seconds=3600), future)
+        self.assertEqual(result, "asdf")
+
+    @gen_test
+    def test_timeout_concurrent_future(self):
+        # A concurrent future that does not resolve before the timeout.
+        with futures.ThreadPoolExecutor(1) as executor:
+            with self.assertRaises(gen.TimeoutError):
+                yield gen.with_timeout(
+                    self.io_loop.time(), executor.submit(time.sleep, 0.1)
+                )
+
+    @gen_test
+    def test_completed_concurrent_future(self):
+        # A concurrent future that is resolved before we even submit it
+        # to with_timeout.
+        with futures.ThreadPoolExecutor(1) as executor:
+
+            def dummy():
+                pass
+
+            f = executor.submit(dummy)
+            f.result()  # wait for completion
+            yield gen.with_timeout(datetime.timedelta(seconds=3600), f)
+
+    @gen_test
+    def test_normal_concurrent_future(self):
+        # A conccurrent future that resolves while waiting for the timeout.
+        with futures.ThreadPoolExecutor(1) as executor:
+            yield gen.with_timeout(
+                datetime.timedelta(seconds=3600),
+                executor.submit(lambda: time.sleep(0.01)),
+            )
+
+
+class WaitIteratorTest(AsyncTestCase):
+    @gen_test
+    def test_empty_iterator(self):
+        g = gen.WaitIterator()
+        self.assertTrue(g.done(), "empty generator iterated")
+
+        with self.assertRaises(ValueError):
+            g = gen.WaitIterator(Future(), bar=Future())
+
+        self.assertEqual(g.current_index, None, "bad nil current index")
+        self.assertEqual(g.current_future, None, "bad nil current future")
+
+    @gen_test
+    def test_already_done(self):
+        f1 = Future()  # type: Future[int]
+        f2 = Future()  # type: Future[int]
+        f3 = Future()  # type: Future[int]
+        f1.set_result(24)
+        f2.set_result(42)
+        f3.set_result(84)
+
+        g = gen.WaitIterator(f1, f2, f3)
+        i = 0
+        while not g.done():
+            r = yield g.next()
+            # Order is not guaranteed, but the current implementation
+            # preserves ordering of already-done Futures.
+            if i == 0:
+                self.assertEqual(g.current_index, 0)
+                self.assertIs(g.current_future, f1)
+                self.assertEqual(r, 24)
+            elif i == 1:
+                self.assertEqual(g.current_index, 1)
+                self.assertIs(g.current_future, f2)
+                self.assertEqual(r, 42)
+            elif i == 2:
+                self.assertEqual(g.current_index, 2)
+                self.assertIs(g.current_future, f3)
+                self.assertEqual(r, 84)
+            i += 1
+
+        self.assertEqual(g.current_index, None, "bad nil current index")
+        self.assertEqual(g.current_future, None, "bad nil current future")
+
+        dg = gen.WaitIterator(f1=f1, f2=f2)
+
+        while not dg.done():
+            dr = yield dg.next()
+            if dg.current_index == "f1":
+                self.assertTrue(
+                    dg.current_future == f1 and dr == 24,
+                    "WaitIterator dict status incorrect",
+                )
+            elif dg.current_index == "f2":
+                self.assertTrue(
+                    dg.current_future == f2 and dr == 42,
+                    "WaitIterator dict status incorrect",
+                )
+            else:
+                self.fail("got bad WaitIterator index {}".format(dg.current_index))
+
+            i += 1
+
+        self.assertEqual(dg.current_index, None, "bad nil current index")
+        self.assertEqual(dg.current_future, None, "bad nil current future")
+
+    def finish_coroutines(self, iteration, futures):
+        if iteration == 3:
+            futures[2].set_result(24)
+        elif iteration == 5:
+            futures[0].set_exception(ZeroDivisionError())
+        elif iteration == 8:
+            futures[1].set_result(42)
+            futures[3].set_result(84)
+
+        if iteration < 8:
+            self.io_loop.add_callback(self.finish_coroutines, iteration + 1, futures)
+
+    @gen_test
+    def test_iterator(self):
+        futures = [Future(), Future(), Future(), Future()]  # type: List[Future[int]]
+
+        self.finish_coroutines(0, futures)
+
+        g = gen.WaitIterator(*futures)
+
+        i = 0
+        while not g.done():
+            try:
+                r = yield g.next()
+            except ZeroDivisionError:
+                self.assertIs(g.current_future, futures[0], "exception future invalid")
+            else:
+                if i == 0:
+                    self.assertEqual(r, 24, "iterator value incorrect")
+                    self.assertEqual(g.current_index, 2, "wrong index")
+                elif i == 2:
+                    self.assertEqual(r, 42, "iterator value incorrect")
+                    self.assertEqual(g.current_index, 1, "wrong index")
+                elif i == 3:
+                    self.assertEqual(r, 84, "iterator value incorrect")
+                    self.assertEqual(g.current_index, 3, "wrong index")
+            i += 1
+
+    @gen_test
+    def test_iterator_async_await(self):
+        # Recreate the previous test with py35 syntax. It's a little clunky
+        # because of the way the previous test handles an exception on
+        # a single iteration.
+        futures = [Future(), Future(), Future(), Future()]  # type: List[Future[int]]
+        self.finish_coroutines(0, futures)
+        self.finished = False
+
+        async def f():
+            i = 0
+            g = gen.WaitIterator(*futures)
+            try:
+                async for r in g:
+                    if i == 0:
+                        self.assertEqual(r, 24, "iterator value incorrect")
+                        self.assertEqual(g.current_index, 2, "wrong index")
+                    else:
+                        raise Exception("expected exception on iteration 1")
+                    i += 1
+            except ZeroDivisionError:
+                i += 1
+            async for r in g:
+                if i == 2:
+                    self.assertEqual(r, 42, "iterator value incorrect")
+                    self.assertEqual(g.current_index, 1, "wrong index")
+                elif i == 3:
+                    self.assertEqual(r, 84, "iterator value incorrect")
+                    self.assertEqual(g.current_index, 3, "wrong index")
+                else:
+                    raise Exception("didn't expect iteration %d" % i)
+                i += 1
+            self.finished = True
+
+        yield f()
+        self.assertTrue(self.finished)
+
+    @gen_test
+    def test_no_ref(self):
+        # In this usage, there is no direct hard reference to the
+        # WaitIterator itself, only the Future it returns. Since
+        # WaitIterator uses weak references internally to improve GC
+        # performance, this used to cause problems.
+        yield gen.with_timeout(
+            datetime.timedelta(seconds=0.1), gen.WaitIterator(gen.sleep(0)).next()
+        )
+
+
+class RunnerGCTest(AsyncTestCase):
+    def is_pypy3(self):
+        return platform.python_implementation() == "PyPy" and sys.version_info > (3,)
+
+    @gen_test
+    def test_gc(self):
+        # GitHub issue 1769: Runner objects can get GCed unexpectedly
+        # while their future is alive.
+        weakref_scope = [None]  # type: List[Optional[weakref.ReferenceType]]
+
+        def callback():
+            gc.collect(2)
+            weakref_scope[0]().set_result(123)  # type: ignore
+
+        @gen.coroutine
+        def tester():
+            fut = Future()  # type: Future[int]
+            weakref_scope[0] = weakref.ref(fut)
+            self.io_loop.add_callback(callback)
+            yield fut
+
+        yield gen.with_timeout(datetime.timedelta(seconds=0.2), tester())
+
+    def test_gc_infinite_coro(self):
+        # GitHub issue 2229: suspended coroutines should be GCed when
+        # their loop is closed, even if they're involved in a reference
+        # cycle.
+        loop = self.get_new_ioloop()
+        result = []  # type: List[Optional[bool]]
+        wfut = []
+
+        @gen.coroutine
+        def infinite_coro():
+            try:
+                while True:
+                    yield gen.sleep(1e-3)
+                    result.append(True)
+            finally:
+                # coroutine finalizer
+                result.append(None)
+
+        @gen.coroutine
+        def do_something():
+            fut = infinite_coro()
+            fut._refcycle = fut  # type: ignore
+            wfut.append(weakref.ref(fut))
+            yield gen.sleep(0.2)
+
+        loop.run_sync(do_something)
+        loop.close()
+        gc.collect()
+        # Future was collected
+        self.assertIs(wfut[0](), None)
+        # At least one wakeup
+        self.assertGreaterEqual(len(result), 2)
+        if not self.is_pypy3():
+            # coroutine finalizer was called (not on PyPy3 apparently)
+            self.assertIs(result[-1], None)
+
+    def test_gc_infinite_async_await(self):
+        # Same as test_gc_infinite_coro, but with a `async def` function
+        import asyncio
+
+        async def infinite_coro(result):
+            try:
+                while True:
+                    await gen.sleep(1e-3)
+                    result.append(True)
+            finally:
+                # coroutine finalizer
+                result.append(None)
+
+        loop = self.get_new_ioloop()
+        result = []  # type: List[Optional[bool]]
+        wfut = []
+
+        @gen.coroutine
+        def do_something():
+            fut = asyncio.get_event_loop().create_task(infinite_coro(result))
+            fut._refcycle = fut  # type: ignore
+            wfut.append(weakref.ref(fut))
+            yield gen.sleep(0.2)
+
+        loop.run_sync(do_something)
+        with ExpectLog("asyncio", "Task was destroyed but it is pending"):
+            loop.close()
+            gc.collect()
+        # Future was collected
+        self.assertIs(wfut[0](), None)
+        # At least one wakeup and one finally
+        self.assertGreaterEqual(len(result), 2)
+        if not self.is_pypy3():
+            # coroutine finalizer was called (not on PyPy3 apparently)
+            self.assertIs(result[-1], None)
+
+    def test_multi_moment(self):
+        # Test gen.multi with moment
+        # now that it's not a real Future
+        @gen.coroutine
+        def wait_a_moment():
+            result = yield gen.multi([gen.moment, gen.moment])
+            raise gen.Return(result)
+
+        loop = self.get_new_ioloop()
+        result = loop.run_sync(wait_a_moment)
+        self.assertEqual(result, [None, None])
+
+
+if contextvars is not None:
+    ctx_var = contextvars.ContextVar("ctx_var")  # type: contextvars.ContextVar[int]
+
+
+@unittest.skipIf(contextvars is None, "contextvars module not present")
+class ContextVarsTest(AsyncTestCase):
+    async def native_root(self, x):
+        ctx_var.set(x)
+        await self.inner(x)
+
+    @gen.coroutine
+    def gen_root(self, x):
+        ctx_var.set(x)
+        yield
+        yield self.inner(x)
+
+    async def inner(self, x):
+        self.assertEqual(ctx_var.get(), x)
+        await self.gen_inner(x)
+        self.assertEqual(ctx_var.get(), x)
+
+        # IOLoop.run_in_executor doesn't automatically copy context
+        ctx = contextvars.copy_context()
+        await self.io_loop.run_in_executor(None, lambda: ctx.run(self.thread_inner, x))
+        self.assertEqual(ctx_var.get(), x)
+
+        # Neither does asyncio's run_in_executor.
+        await asyncio.get_event_loop().run_in_executor(
+            None, lambda: ctx.run(self.thread_inner, x)
+        )
+        self.assertEqual(ctx_var.get(), x)
+
+    @gen.coroutine
+    def gen_inner(self, x):
+        self.assertEqual(ctx_var.get(), x)
+        yield
+        self.assertEqual(ctx_var.get(), x)
+
+    def thread_inner(self, x):
+        self.assertEqual(ctx_var.get(), x)
+
+    @gen_test
+    def test_propagate(self):
+        # Verify that context vars get propagated across various
+        # combinations of native and decorated coroutines.
+        yield [
+            self.native_root(1),
+            self.native_root(2),
+            self.gen_root(3),
+            self.gen_root(4),
+        ]
+
+    @gen_test
+    def test_reset(self):
+        token = ctx_var.set(1)
+        yield
+        # reset asserts that we are still at the same level of the context tree,
+        # so we must make sure that we maintain that property across yield.
+        ctx_var.reset(token)
+
+    @gen_test
+    def test_propagate_to_first_yield_with_native_async_function(self):
+        x = 10
+
+        async def native_async_function():
+            self.assertEqual(ctx_var.get(), x)
+
+        ctx_var.set(x)
+        yield native_async_function()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.mo b/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.mo
new file mode 100644
index 00000000..a97bf9c5
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.mo
diff --git a/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.po b/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.po
new file mode 100644
index 00000000..88d72c86
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/gettext_translations/fr_FR/LC_MESSAGES/tornado_test.po
@@ -0,0 +1,47 @@
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the PACKAGE package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PACKAGE VERSION\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2015-01-27 11:05+0300\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\n"
+
+#: extract_me.py:11
+msgid "school"
+msgstr "école"
+
+#: extract_me.py:12
+msgctxt "law"
+msgid "right"
+msgstr "le droit"
+
+#: extract_me.py:13
+msgctxt "good"
+msgid "right"
+msgstr "le bien"
+
+#: extract_me.py:14
+msgctxt "organization"
+msgid "club"
+msgid_plural "clubs"
+msgstr[0] "le club"
+msgstr[1] "les clubs"
+
+#: extract_me.py:15
+msgctxt "stick"
+msgid "club"
+msgid_plural "clubs"
+msgstr[0] "le bâton"
+msgstr[1] "les bâtons"
diff --git a/venv/lib/python3.9/site-packages/tornado/test/http1connection_test.py b/venv/lib/python3.9/site-packages/tornado/test/http1connection_test.py
new file mode 100644
index 00000000..34de6d38
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/http1connection_test.py
@@ -0,0 +1,61 @@
+import socket
+import typing  # noqa(F401)
+
+from tornado.http1connection import HTTP1Connection
+from tornado.httputil import HTTPMessageDelegate
+from tornado.iostream import IOStream
+from tornado.locks import Event
+from tornado.netutil import add_accept_handler
+from tornado.testing import AsyncTestCase, bind_unused_port, gen_test
+
+
+class HTTP1ConnectionTest(AsyncTestCase):
+    code = None  # type: typing.Optional[int]
+
+    def setUp(self):
+        super().setUp()
+        self.asyncSetUp()
+
+    @gen_test
+    def asyncSetUp(self):
+        listener, port = bind_unused_port()
+        event = Event()
+
+        def accept_callback(conn, addr):
+            self.server_stream = IOStream(conn)
+            self.addCleanup(self.server_stream.close)
+            event.set()
+
+        add_accept_handler(listener, accept_callback)
+        self.client_stream = IOStream(socket.socket())
+        self.addCleanup(self.client_stream.close)
+        yield [self.client_stream.connect(("127.0.0.1", port)), event.wait()]
+        self.io_loop.remove_handler(listener)
+        listener.close()
+
+    @gen_test
+    def test_http10_no_content_length(self):
+        # Regression test for a bug in which can_keep_alive would crash
+        # for an HTTP/1.0 (not 1.1) response with no content-length.
+        conn = HTTP1Connection(self.client_stream, True)
+        self.server_stream.write(b"HTTP/1.0 200 Not Modified\r\n\r\nhello")
+        self.server_stream.close()
+
+        event = Event()
+        test = self
+        body = []
+
+        class Delegate(HTTPMessageDelegate):
+            def headers_received(self, start_line, headers):
+                test.code = start_line.code
+
+            def data_received(self, data):
+                body.append(data)
+
+            def finish(self):
+                event.set()
+
+        yield conn.read_response(Delegate())
+        yield event.wait()
+        self.assertEqual(self.code, 200)
+        self.assertEqual(b"".join(body), b"hello")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/httpclient_test.py b/venv/lib/python3.9/site-packages/tornado/test/httpclient_test.py
new file mode 100644
index 00000000..a71ec0af
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/httpclient_test.py
@@ -0,0 +1,915 @@
+import base64
+import binascii
+from contextlib import closing
+import copy
+import gzip
+import threading
+import datetime
+from io import BytesIO
+import subprocess
+import sys
+import time
+import typing  # noqa: F401
+import unicodedata
+import unittest
+
+from tornado.escape import utf8, native_str, to_unicode
+from tornado import gen
+from tornado.httpclient import (
+    HTTPRequest,
+    HTTPResponse,
+    _RequestProxy,
+    HTTPError,
+    HTTPClient,
+)
+from tornado.httpserver import HTTPServer
+from tornado.ioloop import IOLoop
+from tornado.iostream import IOStream
+from tornado.log import gen_log, app_log
+from tornado import netutil
+from tornado.testing import AsyncHTTPTestCase, bind_unused_port, gen_test, ExpectLog
+from tornado.test.util import skipOnTravis
+from tornado.web import Application, RequestHandler, url
+from tornado.httputil import format_timestamp, HTTPHeaders
+
+
+class HelloWorldHandler(RequestHandler):
+    def get(self):
+        name = self.get_argument("name", "world")
+        self.set_header("Content-Type", "text/plain")
+        self.finish("Hello %s!" % name)
+
+
+class PostHandler(RequestHandler):
+    def post(self):
+        self.finish(
+            "Post arg1: %s, arg2: %s"
+            % (self.get_argument("arg1"), self.get_argument("arg2"))
+        )
+
+
+class PutHandler(RequestHandler):
+    def put(self):
+        self.write("Put body: ")
+        self.write(self.request.body)
+
+
+class RedirectHandler(RequestHandler):
+    def prepare(self):
+        self.write("redirects can have bodies too")
+        self.redirect(
+            self.get_argument("url"), status=int(self.get_argument("status", "302"))
+        )
+
+
+class RedirectWithoutLocationHandler(RequestHandler):
+    def prepare(self):
+        # For testing error handling of a redirect with no location header.
+        self.set_status(301)
+        self.finish()
+
+
+class ChunkHandler(RequestHandler):
+    @gen.coroutine
+    def get(self):
+        self.write("asdf")
+        self.flush()
+        # Wait a bit to ensure the chunks are sent and received separately.
+        yield gen.sleep(0.01)
+        self.write("qwer")
+
+
+class AuthHandler(RequestHandler):
+    def get(self):
+        self.finish(self.request.headers["Authorization"])
+
+
+class CountdownHandler(RequestHandler):
+    def get(self, count):
+        count = int(count)
+        if count > 0:
+            self.redirect(self.reverse_url("countdown", count - 1))
+        else:
+            self.write("Zero")
+
+
+class EchoPostHandler(RequestHandler):
+    def post(self):
+        self.write(self.request.body)
+
+
+class UserAgentHandler(RequestHandler):
+    def get(self):
+        self.write(self.request.headers.get("User-Agent", "User agent not set"))
+
+
+class ContentLength304Handler(RequestHandler):
+    def get(self):
+        self.set_status(304)
+        self.set_header("Content-Length", 42)
+
+    def _clear_representation_headers(self):
+        # Tornado strips content-length from 304 responses, but here we
+        # want to simulate servers that include the headers anyway.
+        pass
+
+
+class PatchHandler(RequestHandler):
+    def patch(self):
+        "Return the request payload - so we can check it is being kept"
+        self.write(self.request.body)
+
+
+class AllMethodsHandler(RequestHandler):
+    SUPPORTED_METHODS = RequestHandler.SUPPORTED_METHODS + ("OTHER",)  # type: ignore
+
+    def method(self):
+        assert self.request.method is not None
+        self.write(self.request.method)
+
+    get = head = post = put = delete = options = patch = other = method  # type: ignore
+
+
+class SetHeaderHandler(RequestHandler):
+    def get(self):
+        # Use get_arguments for keys to get strings, but
+        # request.arguments for values to get bytes.
+        for k, v in zip(self.get_arguments("k"), self.request.arguments["v"]):
+            self.set_header(k, v)
+
+
+class InvalidGzipHandler(RequestHandler):
+    def get(self) -> None:
+        # set Content-Encoding manually to avoid automatic gzip encoding
+        self.set_header("Content-Type", "text/plain")
+        self.set_header("Content-Encoding", "gzip")
+        # Triggering the potential bug seems to depend on input length.
+        # This length is taken from the bad-response example reported in
+        # https://github.com/tornadoweb/tornado/pull/2875 (uncompressed).
+        text = "".join("Hello World {}\n".format(i) for i in range(9000))[:149051]
+        body = gzip.compress(text.encode(), compresslevel=6) + b"\00"
+        self.write(body)
+
+
+class HeaderEncodingHandler(RequestHandler):
+    def get(self):
+        self.finish(self.request.headers["Foo"].encode("ISO8859-1"))
+
+
+# These tests end up getting run redundantly: once here with the default
+# HTTPClient implementation, and then again in each implementation's own
+# test suite.
+
+
+class HTTPClientCommonTestCase(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application(
+            [
+                url("/hello", HelloWorldHandler),
+                url("/post", PostHandler),
+                url("/put", PutHandler),
+                url("/redirect", RedirectHandler),
+                url("/redirect_without_location", RedirectWithoutLocationHandler),
+                url("/chunk", ChunkHandler),
+                url("/auth", AuthHandler),
+                url("/countdown/([0-9]+)", CountdownHandler, name="countdown"),
+                url("/echopost", EchoPostHandler),
+                url("/user_agent", UserAgentHandler),
+                url("/304_with_content_length", ContentLength304Handler),
+                url("/all_methods", AllMethodsHandler),
+                url("/patch", PatchHandler),
+                url("/set_header", SetHeaderHandler),
+                url("/invalid_gzip", InvalidGzipHandler),
+                url("/header-encoding", HeaderEncodingHandler),
+            ],
+            gzip=True,
+        )
+
+    def test_patch_receives_payload(self):
+        body = b"some patch data"
+        response = self.fetch("/patch", method="PATCH", body=body)
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.body, body)
+
+    @skipOnTravis
+    def test_hello_world(self):
+        response = self.fetch("/hello")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.headers["Content-Type"], "text/plain")
+        self.assertEqual(response.body, b"Hello world!")
+        assert response.request_time is not None
+        self.assertEqual(int(response.request_time), 0)
+
+        response = self.fetch("/hello?name=Ben")
+        self.assertEqual(response.body, b"Hello Ben!")
+
+    def test_streaming_callback(self):
+        # streaming_callback is also tested in test_chunked
+        chunks = []  # type: typing.List[bytes]
+        response = self.fetch("/hello", streaming_callback=chunks.append)
+        # with streaming_callback, data goes to the callback and not response.body
+        self.assertEqual(chunks, [b"Hello world!"])
+        self.assertFalse(response.body)
+
+    def test_post(self):
+        response = self.fetch("/post", method="POST", body="arg1=foo&arg2=bar")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.body, b"Post arg1: foo, arg2: bar")
+
+    def test_chunked(self):
+        response = self.fetch("/chunk")
+        self.assertEqual(response.body, b"asdfqwer")
+
+        chunks = []  # type: typing.List[bytes]
+        response = self.fetch("/chunk", streaming_callback=chunks.append)
+        self.assertEqual(chunks, [b"asdf", b"qwer"])
+        self.assertFalse(response.body)
+
+    def test_chunked_close(self):
+        # test case in which chunks spread read-callback processing
+        # over several ioloop iterations, but the connection is already closed.
+        sock, port = bind_unused_port()
+        with closing(sock):
+
+            @gen.coroutine
+            def accept_callback(conn, address):
+                # fake an HTTP server using chunked encoding where the final chunks
+                # and connection close all happen at once
+                stream = IOStream(conn)
+                request_data = yield stream.read_until(b"\r\n\r\n")
+                if b"HTTP/1." not in request_data:
+                    self.skipTest("requires HTTP/1.x")
+                yield stream.write(
+                    b"""\
+HTTP/1.1 200 OK
+Transfer-Encoding: chunked
+
+1
+1
+1
+2
+0
+
+""".replace(
+                        b"\n", b"\r\n"
+                    )
+                )
+                stream.close()
+
+            netutil.add_accept_handler(sock, accept_callback)  # type: ignore
+            resp = self.fetch("http://127.0.0.1:%d/" % port)
+            resp.rethrow()
+            self.assertEqual(resp.body, b"12")
+            self.io_loop.remove_handler(sock.fileno())
+
+    def test_basic_auth(self):
+        # This test data appears in section 2 of RFC 7617.
+        self.assertEqual(
+            self.fetch(
+                "/auth", auth_username="Aladdin", auth_password="open sesame"
+            ).body,
+            b"Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==",
+        )
+
+    def test_basic_auth_explicit_mode(self):
+        self.assertEqual(
+            self.fetch(
+                "/auth",
+                auth_username="Aladdin",
+                auth_password="open sesame",
+                auth_mode="basic",
+            ).body,
+            b"Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==",
+        )
+
+    def test_basic_auth_unicode(self):
+        # This test data appears in section 2.1 of RFC 7617.
+        self.assertEqual(
+            self.fetch("/auth", auth_username="test", auth_password="123£").body,
+            b"Basic dGVzdDoxMjPCow==",
+        )
+
+        # The standard mandates NFC. Give it a decomposed username
+        # and ensure it is normalized to composed form.
+        username = unicodedata.normalize("NFD", "josé")
+        self.assertEqual(
+            self.fetch("/auth", auth_username=username, auth_password="səcrət").body,
+            b"Basic am9zw6k6c8mZY3LJmXQ=",
+        )
+
+    def test_unsupported_auth_mode(self):
+        # curl and simple clients handle errors a bit differently; the
+        # important thing is that they don't fall back to basic auth
+        # on an unknown mode.
+        with ExpectLog(gen_log, "uncaught exception", required=False):
+            with self.assertRaises((ValueError, HTTPError)):  # type: ignore
+                self.fetch(
+                    "/auth",
+                    auth_username="Aladdin",
+                    auth_password="open sesame",
+                    auth_mode="asdf",
+                    raise_error=True,
+                )
+
+    def test_follow_redirect(self):
+        response = self.fetch("/countdown/2", follow_redirects=False)
+        self.assertEqual(302, response.code)
+        self.assertTrue(response.headers["Location"].endswith("/countdown/1"))
+
+        response = self.fetch("/countdown/2")
+        self.assertEqual(200, response.code)
+        self.assertTrue(response.effective_url.endswith("/countdown/0"))
+        self.assertEqual(b"Zero", response.body)
+
+    def test_redirect_without_location(self):
+        response = self.fetch("/redirect_without_location", follow_redirects=True)
+        # If there is no location header, the redirect response should
+        # just be returned as-is. (This should arguably raise an
+        # error, but libcurl doesn't treat this as an error, so we
+        # don't either).
+        self.assertEqual(301, response.code)
+
+    def test_redirect_put_with_body(self):
+        response = self.fetch(
+            "/redirect?url=/put&status=307", method="PUT", body="hello"
+        )
+        self.assertEqual(response.body, b"Put body: hello")
+
+    def test_redirect_put_without_body(self):
+        # This "without body" edge case is similar to what happens with body_producer.
+        response = self.fetch(
+            "/redirect?url=/put&status=307",
+            method="PUT",
+            allow_nonstandard_methods=True,
+        )
+        self.assertEqual(response.body, b"Put body: ")
+
+    def test_method_after_redirect(self):
+        # Legacy redirect codes (301, 302) convert POST requests to GET.
+        for status in [301, 302, 303]:
+            url = "/redirect?url=/all_methods&status=%d" % status
+            resp = self.fetch(url, method="POST", body=b"")
+            self.assertEqual(b"GET", resp.body)
+
+            # Other methods are left alone, except for 303 redirect, depending on client
+            for method in ["GET", "OPTIONS", "PUT", "DELETE"]:
+                resp = self.fetch(url, method=method, allow_nonstandard_methods=True)
+                if status in [301, 302]:
+                    self.assertEqual(utf8(method), resp.body)
+                else:
+                    self.assertIn(resp.body, [utf8(method), b"GET"])
+
+            # HEAD is different so check it separately.
+            resp = self.fetch(url, method="HEAD")
+            self.assertEqual(200, resp.code)
+            self.assertEqual(b"", resp.body)
+
+        # Newer redirects always preserve the original method.
+        for status in [307, 308]:
+            url = "/redirect?url=/all_methods&status=307"
+            for method in ["GET", "OPTIONS", "POST", "PUT", "DELETE"]:
+                resp = self.fetch(url, method=method, allow_nonstandard_methods=True)
+                self.assertEqual(method, to_unicode(resp.body))
+            resp = self.fetch(url, method="HEAD")
+            self.assertEqual(200, resp.code)
+            self.assertEqual(b"", resp.body)
+
+    def test_credentials_in_url(self):
+        url = self.get_url("/auth").replace("http://", "http://me:secret@")
+        response = self.fetch(url)
+        self.assertEqual(b"Basic " + base64.b64encode(b"me:secret"), response.body)
+
+    def test_body_encoding(self):
+        unicode_body = "\xe9"
+        byte_body = binascii.a2b_hex(b"e9")
+
+        # unicode string in body gets converted to utf8
+        response = self.fetch(
+            "/echopost",
+            method="POST",
+            body=unicode_body,
+            headers={"Content-Type": "application/blah"},
+        )
+        self.assertEqual(response.headers["Content-Length"], "2")
+        self.assertEqual(response.body, utf8(unicode_body))
+
+        # byte strings pass through directly
+        response = self.fetch(
+            "/echopost",
+            method="POST",
+            body=byte_body,
+            headers={"Content-Type": "application/blah"},
+        )
+        self.assertEqual(response.headers["Content-Length"], "1")
+        self.assertEqual(response.body, byte_body)
+
+        # Mixing unicode in headers and byte string bodies shouldn't
+        # break anything
+        response = self.fetch(
+            "/echopost",
+            method="POST",
+            body=byte_body,
+            headers={"Content-Type": "application/blah"},
+            user_agent="foo",
+        )
+        self.assertEqual(response.headers["Content-Length"], "1")
+        self.assertEqual(response.body, byte_body)
+
+    def test_types(self):
+        response = self.fetch("/hello")
+        self.assertEqual(type(response.body), bytes)
+        self.assertEqual(type(response.headers["Content-Type"]), str)
+        self.assertEqual(type(response.code), int)
+        self.assertEqual(type(response.effective_url), str)
+
+    def test_gzip(self):
+        # All the tests in this file should be using gzip, but this test
+        # ensures that it is in fact getting compressed, and also tests
+        # the httpclient's decompress=False option.
+        # Setting Accept-Encoding manually bypasses the client's
+        # decompression so we can see the raw data.
+        response = self.fetch(
+            "/chunk", decompress_response=False, headers={"Accept-Encoding": "gzip"}
+        )
+        self.assertEqual(response.headers["Content-Encoding"], "gzip")
+        self.assertNotEqual(response.body, b"asdfqwer")
+        # Our test data gets bigger when gzipped.  Oops.  :)
+        # Chunked encoding bypasses the MIN_LENGTH check.
+        self.assertEqual(len(response.body), 34)
+        f = gzip.GzipFile(mode="r", fileobj=response.buffer)
+        self.assertEqual(f.read(), b"asdfqwer")
+
+    def test_invalid_gzip(self):
+        # test if client hangs on tricky invalid gzip
+        # curl/simple httpclient have different behavior (exception, logging)
+        with ExpectLog(
+            app_log, "(Uncaught exception|Exception in callback)", required=False
+        ):
+            try:
+                response = self.fetch("/invalid_gzip")
+                self.assertEqual(response.code, 200)
+                self.assertEqual(response.body[:14], b"Hello World 0\n")
+            except HTTPError:
+                pass  # acceptable
+
+    def test_header_callback(self):
+        first_line = []
+        headers = {}
+        chunks = []
+
+        def header_callback(header_line):
+            if header_line.startswith("HTTP/1.1 101"):
+                # Upgrading to HTTP/2
+                pass
+            elif header_line.startswith("HTTP/"):
+                first_line.append(header_line)
+            elif header_line != "\r\n":
+                k, v = header_line.split(":", 1)
+                headers[k.lower()] = v.strip()
+
+        def streaming_callback(chunk):
+            # All header callbacks are run before any streaming callbacks,
+            # so the header data is available to process the data as it
+            # comes in.
+            self.assertEqual(headers["content-type"], "text/html; charset=UTF-8")
+            chunks.append(chunk)
+
+        self.fetch(
+            "/chunk",
+            header_callback=header_callback,
+            streaming_callback=streaming_callback,
+        )
+        self.assertEqual(len(first_line), 1, first_line)
+        self.assertRegex(first_line[0], "HTTP/[0-9]\\.[0-9] 200.*\r\n")
+        self.assertEqual(chunks, [b"asdf", b"qwer"])
+
+    @gen_test
+    def test_configure_defaults(self):
+        defaults = dict(user_agent="TestDefaultUserAgent", allow_ipv6=False)
+        # Construct a new instance of the configured client class
+        client = self.http_client.__class__(force_instance=True, defaults=defaults)
+        try:
+            response = yield client.fetch(self.get_url("/user_agent"))
+            self.assertEqual(response.body, b"TestDefaultUserAgent")
+        finally:
+            client.close()
+
+    def test_header_types(self):
+        # Header values may be passed as character or utf8 byte strings,
+        # in a plain dictionary or an HTTPHeaders object.
+        # Keys must always be the native str type.
+        # All combinations should have the same results on the wire.
+        for value in ["MyUserAgent", b"MyUserAgent"]:
+            for container in [dict, HTTPHeaders]:
+                headers = container()
+                headers["User-Agent"] = value
+                resp = self.fetch("/user_agent", headers=headers)
+                self.assertEqual(
+                    resp.body,
+                    b"MyUserAgent",
+                    "response=%r, value=%r, container=%r"
+                    % (resp.body, value, container),
+                )
+
+    def test_multi_line_headers(self):
+        # Multi-line http headers are rare but rfc-allowed
+        # http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
+        sock, port = bind_unused_port()
+        with closing(sock):
+
+            @gen.coroutine
+            def accept_callback(conn, address):
+                stream = IOStream(conn)
+                request_data = yield stream.read_until(b"\r\n\r\n")
+                if b"HTTP/1." not in request_data:
+                    self.skipTest("requires HTTP/1.x")
+                yield stream.write(
+                    b"""\
+HTTP/1.1 200 OK
+X-XSS-Protection: 1;
+\tmode=block
+
+""".replace(
+                        b"\n", b"\r\n"
+                    )
+                )
+                stream.close()
+
+            netutil.add_accept_handler(sock, accept_callback)  # type: ignore
+            try:
+                resp = self.fetch("http://127.0.0.1:%d/" % port)
+                resp.rethrow()
+                self.assertEqual(resp.headers["X-XSS-Protection"], "1; mode=block")
+            finally:
+                self.io_loop.remove_handler(sock.fileno())
+
+    @gen_test
+    def test_header_encoding(self):
+        response = yield self.http_client.fetch(
+            self.get_url("/header-encoding"),
+            headers={
+                "Foo": "b\xe4r",
+            },
+        )
+        self.assertEqual(response.body, "b\xe4r".encode("ISO8859-1"))
+
+    def test_304_with_content_length(self):
+        # According to the spec 304 responses SHOULD NOT include
+        # Content-Length or other entity headers, but some servers do it
+        # anyway.
+        # http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5
+        response = self.fetch("/304_with_content_length")
+        self.assertEqual(response.code, 304)
+        self.assertEqual(response.headers["Content-Length"], "42")
+
+    @gen_test
+    def test_future_interface(self):
+        response = yield self.http_client.fetch(self.get_url("/hello"))
+        self.assertEqual(response.body, b"Hello world!")
+
+    @gen_test
+    def test_future_http_error(self):
+        with self.assertRaises(HTTPError) as context:
+            yield self.http_client.fetch(self.get_url("/notfound"))
+        assert context.exception is not None
+        assert context.exception.response is not None
+        self.assertEqual(context.exception.code, 404)
+        self.assertEqual(context.exception.response.code, 404)
+
+    @gen_test
+    def test_future_http_error_no_raise(self):
+        response = yield self.http_client.fetch(
+            self.get_url("/notfound"), raise_error=False
+        )
+        self.assertEqual(response.code, 404)
+
+    @gen_test
+    def test_reuse_request_from_response(self):
+        # The response.request attribute should be an HTTPRequest, not
+        # a _RequestProxy.
+        # This test uses self.http_client.fetch because self.fetch calls
+        # self.get_url on the input unconditionally.
+        url = self.get_url("/hello")
+        response = yield self.http_client.fetch(url)
+        self.assertEqual(response.request.url, url)
+        self.assertTrue(isinstance(response.request, HTTPRequest))
+        response2 = yield self.http_client.fetch(response.request)
+        self.assertEqual(response2.body, b"Hello world!")
+
+    @gen_test
+    def test_bind_source_ip(self):
+        url = self.get_url("/hello")
+        request = HTTPRequest(url, network_interface="127.0.0.1")
+        response = yield self.http_client.fetch(request)
+        self.assertEqual(response.code, 200)
+
+        with self.assertRaises((ValueError, HTTPError)) as context:  # type: ignore
+            request = HTTPRequest(url, network_interface="not-interface-or-ip")
+            yield self.http_client.fetch(request)
+        self.assertIn("not-interface-or-ip", str(context.exception))
+
+    def test_all_methods(self):
+        for method in ["GET", "DELETE", "OPTIONS"]:
+            response = self.fetch("/all_methods", method=method)
+            self.assertEqual(response.body, utf8(method))
+        for method in ["POST", "PUT", "PATCH"]:
+            response = self.fetch("/all_methods", method=method, body=b"")
+            self.assertEqual(response.body, utf8(method))
+        response = self.fetch("/all_methods", method="HEAD")
+        self.assertEqual(response.body, b"")
+        response = self.fetch(
+            "/all_methods", method="OTHER", allow_nonstandard_methods=True
+        )
+        self.assertEqual(response.body, b"OTHER")
+
+    def test_body_sanity_checks(self):
+        # These methods require a body.
+        for method in ("POST", "PUT", "PATCH"):
+            with self.assertRaises(ValueError) as context:
+                self.fetch("/all_methods", method=method, raise_error=True)
+            self.assertIn("must not be None", str(context.exception))
+
+            resp = self.fetch(
+                "/all_methods", method=method, allow_nonstandard_methods=True
+            )
+            self.assertEqual(resp.code, 200)
+
+        # These methods don't allow a body.
+        for method in ("GET", "DELETE", "OPTIONS"):
+            with self.assertRaises(ValueError) as context:
+                self.fetch(
+                    "/all_methods", method=method, body=b"asdf", raise_error=True
+                )
+            self.assertIn("must be None", str(context.exception))
+
+            # In most cases this can be overridden, but curl_httpclient
+            # does not allow body with a GET at all.
+            if method != "GET":
+                self.fetch(
+                    "/all_methods",
+                    method=method,
+                    body=b"asdf",
+                    allow_nonstandard_methods=True,
+                    raise_error=True,
+                )
+                self.assertEqual(resp.code, 200)
+
+    # This test causes odd failures with the combination of
+    # curl_httpclient (at least with the version of libcurl available
+    # on ubuntu 12.04), TwistedIOLoop, and epoll.  For POST (but not PUT),
+    # curl decides the response came back too soon and closes the connection
+    # to start again.  It does this *before* telling the socket callback to
+    # unregister the FD.  Some IOLoop implementations have special kernel
+    # integration to discover this immediately.  Tornado's IOLoops
+    # ignore errors on remove_handler to accommodate this behavior, but
+    # Twisted's reactor does not.  The removeReader call fails and so
+    # do all future removeAll calls (which our tests do at cleanup).
+    #
+    # def test_post_307(self):
+    #    response = self.fetch("/redirect?status=307&url=/post",
+    #                          method="POST", body=b"arg1=foo&arg2=bar")
+    #    self.assertEqual(response.body, b"Post arg1: foo, arg2: bar")
+
+    def test_put_307(self):
+        response = self.fetch(
+            "/redirect?status=307&url=/put", method="PUT", body=b"hello"
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"Put body: hello")
+
+    def test_non_ascii_header(self):
+        # Non-ascii headers are sent as latin1.
+        response = self.fetch("/set_header?k=foo&v=%E9")
+        response.rethrow()
+        self.assertEqual(response.headers["Foo"], native_str("\u00e9"))
+
+    def test_response_times(self):
+        # A few simple sanity checks of the response time fields to
+        # make sure they're using the right basis (between the
+        # wall-time and monotonic clocks).
+        start_time = time.time()
+        response = self.fetch("/hello")
+        response.rethrow()
+        assert response.request_time is not None
+        self.assertGreaterEqual(response.request_time, 0)
+        self.assertLess(response.request_time, 1.0)
+        # A very crude check to make sure that start_time is based on
+        # wall time and not the monotonic clock.
+        assert response.start_time is not None
+        self.assertLess(abs(response.start_time - start_time), 1.0)
+
+        for k, v in response.time_info.items():
+            self.assertTrue(0 <= v < 1.0, "time_info[%s] out of bounds: %s" % (k, v))
+
+    def test_zero_timeout(self):
+        response = self.fetch("/hello", connect_timeout=0)
+        self.assertEqual(response.code, 200)
+
+        response = self.fetch("/hello", request_timeout=0)
+        self.assertEqual(response.code, 200)
+
+        response = self.fetch("/hello", connect_timeout=0, request_timeout=0)
+        self.assertEqual(response.code, 200)
+
+    @gen_test
+    def test_error_after_cancel(self):
+        fut = self.http_client.fetch(self.get_url("/404"))
+        self.assertTrue(fut.cancel())
+        with ExpectLog(app_log, "Exception after Future was cancelled") as el:
+            # We can't wait on the cancelled Future any more, so just
+            # let the IOLoop run until the exception gets logged (or
+            # not, in which case we exit the loop and ExpectLog will
+            # raise).
+            for i in range(100):
+                yield gen.sleep(0.01)
+                if el.logged_stack:
+                    break
+
+
+class RequestProxyTest(unittest.TestCase):
+    def test_request_set(self):
+        proxy = _RequestProxy(
+            HTTPRequest("http://example.com/", user_agent="foo"), dict()
+        )
+        self.assertEqual(proxy.user_agent, "foo")
+
+    def test_default_set(self):
+        proxy = _RequestProxy(
+            HTTPRequest("http://example.com/"), dict(network_interface="foo")
+        )
+        self.assertEqual(proxy.network_interface, "foo")
+
+    def test_both_set(self):
+        proxy = _RequestProxy(
+            HTTPRequest("http://example.com/", proxy_host="foo"), dict(proxy_host="bar")
+        )
+        self.assertEqual(proxy.proxy_host, "foo")
+
+    def test_neither_set(self):
+        proxy = _RequestProxy(HTTPRequest("http://example.com/"), dict())
+        self.assertIs(proxy.auth_username, None)
+
+    def test_bad_attribute(self):
+        proxy = _RequestProxy(HTTPRequest("http://example.com/"), dict())
+        with self.assertRaises(AttributeError):
+            proxy.foo
+
+    def test_defaults_none(self):
+        proxy = _RequestProxy(HTTPRequest("http://example.com/"), None)
+        self.assertIs(proxy.auth_username, None)
+
+
+class HTTPResponseTestCase(unittest.TestCase):
+    def test_str(self):
+        response = HTTPResponse(  # type: ignore
+            HTTPRequest("http://example.com"), 200, buffer=BytesIO()
+        )
+        s = str(response)
+        self.assertTrue(s.startswith("HTTPResponse("))
+        self.assertIn("code=200", s)
+
+
+class SyncHTTPClientTest(unittest.TestCase):
+    def setUp(self):
+        self.server_ioloop = IOLoop(make_current=False)
+        event = threading.Event()
+
+        @gen.coroutine
+        def init_server():
+            sock, self.port = bind_unused_port()
+            app = Application([("/", HelloWorldHandler)])
+            self.server = HTTPServer(app)
+            self.server.add_socket(sock)
+            event.set()
+
+        def start():
+            self.server_ioloop.run_sync(init_server)
+            self.server_ioloop.start()
+
+        self.server_thread = threading.Thread(target=start)
+        self.server_thread.start()
+        event.wait()
+
+        self.http_client = HTTPClient()
+
+    def tearDown(self):
+        def stop_server():
+            self.server.stop()
+            # Delay the shutdown of the IOLoop by several iterations because
+            # the server may still have some cleanup work left when
+            # the client finishes with the response (this is noticeable
+            # with http/2, which leaves a Future with an unexamined
+            # StreamClosedError on the loop).
+
+            @gen.coroutine
+            def slow_stop():
+                yield self.server.close_all_connections()
+                # The number of iterations is difficult to predict. Typically,
+                # one is sufficient, although sometimes it needs more.
+                for i in range(5):
+                    yield
+                self.server_ioloop.stop()
+
+            self.server_ioloop.add_callback(slow_stop)
+
+        self.server_ioloop.add_callback(stop_server)
+        self.server_thread.join()
+        self.http_client.close()
+        self.server_ioloop.close(all_fds=True)
+
+    def get_url(self, path):
+        return "http://127.0.0.1:%d%s" % (self.port, path)
+
+    def test_sync_client(self):
+        response = self.http_client.fetch(self.get_url("/"))
+        self.assertEqual(b"Hello world!", response.body)
+
+    def test_sync_client_error(self):
+        # Synchronous HTTPClient raises errors directly; no need for
+        # response.rethrow()
+        with self.assertRaises(HTTPError) as assertion:
+            self.http_client.fetch(self.get_url("/notfound"))
+        self.assertEqual(assertion.exception.code, 404)
+
+
+class SyncHTTPClientSubprocessTest(unittest.TestCase):
+    def test_destructor_log(self):
+        # Regression test for
+        # https://github.com/tornadoweb/tornado/issues/2539
+        #
+        # In the past, the following program would log an
+        # "inconsistent AsyncHTTPClient cache" error from a destructor
+        # when the process is shutting down. The shutdown process is
+        # subtle and I don't fully understand it; the failure does not
+        # manifest if that lambda isn't there or is a simpler object
+        # like an int (nor does it manifest in the tornado test suite
+        # as a whole, which is why we use this subprocess).
+        proc = subprocess.run(
+            [
+                sys.executable,
+                "-c",
+                "from tornado.httpclient import HTTPClient; f = lambda: None; c = HTTPClient()",
+            ],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+            check=True,
+            timeout=5,
+        )
+        if proc.stdout:
+            print("STDOUT:")
+            print(to_unicode(proc.stdout))
+        if proc.stdout:
+            self.fail("subprocess produced unexpected output")
+
+
+class HTTPRequestTestCase(unittest.TestCase):
+    def test_headers(self):
+        request = HTTPRequest("http://example.com", headers={"foo": "bar"})
+        self.assertEqual(request.headers, {"foo": "bar"})
+
+    def test_headers_setter(self):
+        request = HTTPRequest("http://example.com")
+        request.headers = {"bar": "baz"}  # type: ignore
+        self.assertEqual(request.headers, {"bar": "baz"})
+
+    def test_null_headers_setter(self):
+        request = HTTPRequest("http://example.com")
+        request.headers = None  # type: ignore
+        self.assertEqual(request.headers, {})
+
+    def test_body(self):
+        request = HTTPRequest("http://example.com", body="foo")
+        self.assertEqual(request.body, utf8("foo"))
+
+    def test_body_setter(self):
+        request = HTTPRequest("http://example.com")
+        request.body = "foo"  # type: ignore
+        self.assertEqual(request.body, utf8("foo"))
+
+    def test_if_modified_since(self):
+        http_date = datetime.datetime.utcnow()
+        request = HTTPRequest("http://example.com", if_modified_since=http_date)
+        self.assertEqual(
+            request.headers, {"If-Modified-Since": format_timestamp(http_date)}
+        )
+
+
+class HTTPErrorTestCase(unittest.TestCase):
+    def test_copy(self):
+        e = HTTPError(403)
+        e2 = copy.copy(e)
+        self.assertIsNot(e, e2)
+        self.assertEqual(e.code, e2.code)
+
+    def test_plain_error(self):
+        e = HTTPError(403)
+        self.assertEqual(str(e), "HTTP 403: Forbidden")
+        self.assertEqual(repr(e), "HTTP 403: Forbidden")
+
+    def test_error_with_response(self):
+        resp = HTTPResponse(HTTPRequest("http://example.com/"), 403)
+        with self.assertRaises(HTTPError) as cm:
+            resp.rethrow()
+        e = cm.exception
+        self.assertEqual(str(e), "HTTP 403: Forbidden")
+        self.assertEqual(repr(e), "HTTP 403: Forbidden")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/httpserver_test.py b/venv/lib/python3.9/site-packages/tornado/test/httpserver_test.py
new file mode 100644
index 00000000..cd0a0e10
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/httpserver_test.py
@@ -0,0 +1,1356 @@
+from tornado import gen, netutil
+from tornado.escape import (
+    json_decode,
+    json_encode,
+    utf8,
+    _unicode,
+    recursive_unicode,
+    native_str,
+)
+from tornado.http1connection import HTTP1Connection
+from tornado.httpclient import HTTPError
+from tornado.httpserver import HTTPServer
+from tornado.httputil import (
+    HTTPHeaders,
+    HTTPMessageDelegate,
+    HTTPServerConnectionDelegate,
+    ResponseStartLine,
+)
+from tornado.iostream import IOStream
+from tornado.locks import Event
+from tornado.log import gen_log
+from tornado.netutil import ssl_options_to_context
+from tornado.simple_httpclient import SimpleAsyncHTTPClient
+from tornado.testing import (
+    AsyncHTTPTestCase,
+    AsyncHTTPSTestCase,
+    AsyncTestCase,
+    ExpectLog,
+    gen_test,
+)
+from tornado.test.util import skipOnTravis
+from tornado.web import Application, RequestHandler, stream_request_body
+
+from contextlib import closing
+import datetime
+import gzip
+import logging
+import os
+import shutil
+import socket
+import ssl
+import sys
+import tempfile
+import unittest
+import urllib.parse
+from io import BytesIO
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Dict, List  # noqa: F401
+
+
+async def read_stream_body(stream):
+    """Reads an HTTP response from `stream` and returns a tuple of its
+    start_line, headers and body."""
+    chunks = []
+
+    class Delegate(HTTPMessageDelegate):
+        def headers_received(self, start_line, headers):
+            self.headers = headers
+            self.start_line = start_line
+
+        def data_received(self, chunk):
+            chunks.append(chunk)
+
+        def finish(self):
+            conn.detach()  # type: ignore
+
+    conn = HTTP1Connection(stream, True)
+    delegate = Delegate()
+    await conn.read_response(delegate)
+    return delegate.start_line, delegate.headers, b"".join(chunks)
+
+
+class HandlerBaseTestCase(AsyncHTTPTestCase):
+    Handler = None
+
+    def get_app(self):
+        return Application([("/", self.__class__.Handler)])
+
+    def fetch_json(self, *args, **kwargs):
+        response = self.fetch(*args, **kwargs)
+        response.rethrow()
+        return json_decode(response.body)
+
+
+class HelloWorldRequestHandler(RequestHandler):
+    def initialize(self, protocol="http"):
+        self.expected_protocol = protocol
+
+    def get(self):
+        if self.request.protocol != self.expected_protocol:
+            raise Exception("unexpected protocol")
+        self.finish("Hello world")
+
+    def post(self):
+        self.finish("Got %d bytes in POST" % len(self.request.body))
+
+
+# In pre-1.0 versions of openssl, SSLv23 clients always send SSLv2
+# ClientHello messages, which are rejected by SSLv3 and TLSv1
+# servers.  Note that while the OPENSSL_VERSION_INFO was formally
+# introduced in python3.2, it was present but undocumented in
+# python 2.7
+skipIfOldSSL = unittest.skipIf(
+    getattr(ssl, "OPENSSL_VERSION_INFO", (0, 0)) < (1, 0),
+    "old version of ssl module and/or openssl",
+)
+
+
+class BaseSSLTest(AsyncHTTPSTestCase):
+    def get_app(self):
+        return Application([("/", HelloWorldRequestHandler, dict(protocol="https"))])
+
+
+class SSLTestMixin(object):
+    def get_ssl_options(self):
+        return dict(
+            ssl_version=self.get_ssl_version(),
+            **AsyncHTTPSTestCase.default_ssl_options()
+        )
+
+    def get_ssl_version(self):
+        raise NotImplementedError()
+
+    def test_ssl(self: typing.Any):
+        response = self.fetch("/")
+        self.assertEqual(response.body, b"Hello world")
+
+    def test_large_post(self: typing.Any):
+        response = self.fetch("/", method="POST", body="A" * 5000)
+        self.assertEqual(response.body, b"Got 5000 bytes in POST")
+
+    def test_non_ssl_request(self: typing.Any):
+        # Make sure the server closes the connection when it gets a non-ssl
+        # connection, rather than waiting for a timeout or otherwise
+        # misbehaving.
+        with ExpectLog(gen_log, "(SSL Error|uncaught exception)"):
+            with ExpectLog(gen_log, "Uncaught exception", required=False):
+                with self.assertRaises((IOError, HTTPError)):  # type: ignore
+                    self.fetch(
+                        self.get_url("/").replace("https:", "http:"),
+                        request_timeout=3600,
+                        connect_timeout=3600,
+                        raise_error=True,
+                    )
+
+    def test_error_logging(self: typing.Any):
+        # No stack traces are logged for SSL errors.
+        with ExpectLog(gen_log, "SSL Error") as expect_log:
+            with self.assertRaises((IOError, HTTPError)):  # type: ignore
+                self.fetch(
+                    self.get_url("/").replace("https:", "http:"), raise_error=True
+                )
+        self.assertFalse(expect_log.logged_stack)
+
+
+# Python's SSL implementation differs significantly between versions.
+# For example, SSLv3 and TLSv1 throw an exception if you try to read
+# from the socket before the handshake is complete, but the default
+# of SSLv23 allows it.
+
+
+class SSLv23Test(BaseSSLTest, SSLTestMixin):
+    def get_ssl_version(self):
+        return ssl.PROTOCOL_SSLv23
+
+
+@skipIfOldSSL
+class SSLv3Test(BaseSSLTest, SSLTestMixin):
+    def get_ssl_version(self):
+        return ssl.PROTOCOL_SSLv3
+
+
+@skipIfOldSSL
+class TLSv1Test(BaseSSLTest, SSLTestMixin):
+    def get_ssl_version(self):
+        return ssl.PROTOCOL_TLSv1
+
+
+class SSLContextTest(BaseSSLTest, SSLTestMixin):
+    def get_ssl_options(self):
+        context = ssl_options_to_context(
+            AsyncHTTPSTestCase.get_ssl_options(self), server_side=True
+        )
+        assert isinstance(context, ssl.SSLContext)
+        return context
+
+
+class BadSSLOptionsTest(unittest.TestCase):
+    def test_missing_arguments(self):
+        application = Application()
+        self.assertRaises(
+            KeyError,
+            HTTPServer,
+            application,
+            ssl_options={"keyfile": "/__missing__.crt"},
+        )
+
+    def test_missing_key(self):
+        """A missing SSL key should cause an immediate exception."""
+
+        application = Application()
+        module_dir = os.path.dirname(__file__)
+        existing_certificate = os.path.join(module_dir, "test.crt")
+        existing_key = os.path.join(module_dir, "test.key")
+
+        self.assertRaises(
+            (ValueError, IOError),
+            HTTPServer,
+            application,
+            ssl_options={"certfile": "/__mising__.crt"},
+        )
+        self.assertRaises(
+            (ValueError, IOError),
+            HTTPServer,
+            application,
+            ssl_options={
+                "certfile": existing_certificate,
+                "keyfile": "/__missing__.key",
+            },
+        )
+
+        # This actually works because both files exist
+        HTTPServer(
+            application,
+            ssl_options={"certfile": existing_certificate, "keyfile": existing_key},
+        )
+
+
+class MultipartTestHandler(RequestHandler):
+    def post(self):
+        self.finish(
+            {
+                "header": self.request.headers["X-Header-Encoding-Test"],
+                "argument": self.get_argument("argument"),
+                "filename": self.request.files["files"][0].filename,
+                "filebody": _unicode(self.request.files["files"][0]["body"]),
+            }
+        )
+
+
+# This test is also called from wsgi_test
+class HTTPConnectionTest(AsyncHTTPTestCase):
+    def get_handlers(self):
+        return [
+            ("/multipart", MultipartTestHandler),
+            ("/hello", HelloWorldRequestHandler),
+        ]
+
+    def get_app(self):
+        return Application(self.get_handlers())
+
+    def raw_fetch(self, headers, body, newline=b"\r\n"):
+        with closing(IOStream(socket.socket())) as stream:
+            self.io_loop.run_sync(
+                lambda: stream.connect(("127.0.0.1", self.get_http_port()))
+            )
+            stream.write(
+                newline.join(headers + [utf8("Content-Length: %d" % len(body))])
+                + newline
+                + newline
+                + body
+            )
+            start_line, headers, body = self.io_loop.run_sync(
+                lambda: read_stream_body(stream)
+            )
+            return body
+
+    def test_multipart_form(self):
+        # Encodings here are tricky:  Headers are latin1, bodies can be
+        # anything (we use utf8 by default).
+        response = self.raw_fetch(
+            [
+                b"POST /multipart HTTP/1.0",
+                b"Content-Type: multipart/form-data; boundary=1234567890",
+                b"X-Header-encoding-test: \xe9",
+            ],
+            b"\r\n".join(
+                [
+                    b"Content-Disposition: form-data; name=argument",
+                    b"",
+                    "\u00e1".encode("utf-8"),
+                    b"--1234567890",
+                    'Content-Disposition: form-data; name="files"; filename="\u00f3"'.encode(
+                        "utf8"
+                    ),
+                    b"",
+                    "\u00fa".encode("utf-8"),
+                    b"--1234567890--",
+                    b"",
+                ]
+            ),
+        )
+        data = json_decode(response)
+        self.assertEqual("\u00e9", data["header"])
+        self.assertEqual("\u00e1", data["argument"])
+        self.assertEqual("\u00f3", data["filename"])
+        self.assertEqual("\u00fa", data["filebody"])
+
+    def test_newlines(self):
+        # We support both CRLF and bare LF as line separators.
+        for newline in (b"\r\n", b"\n"):
+            response = self.raw_fetch([b"GET /hello HTTP/1.0"], b"", newline=newline)
+            self.assertEqual(response, b"Hello world")
+
+    @gen_test
+    def test_100_continue(self):
+        # Run through a 100-continue interaction by hand:
+        # When given Expect: 100-continue, we get a 100 response after the
+        # headers, and then the real response after the body.
+        stream = IOStream(socket.socket())
+        yield stream.connect(("127.0.0.1", self.get_http_port()))
+        yield stream.write(
+            b"\r\n".join(
+                [
+                    b"POST /hello HTTP/1.1",
+                    b"Content-Length: 1024",
+                    b"Expect: 100-continue",
+                    b"Connection: close",
+                    b"\r\n",
+                ]
+            )
+        )
+        data = yield stream.read_until(b"\r\n\r\n")
+        self.assertTrue(data.startswith(b"HTTP/1.1 100 "), data)
+        stream.write(b"a" * 1024)
+        first_line = yield stream.read_until(b"\r\n")
+        self.assertTrue(first_line.startswith(b"HTTP/1.1 200"), first_line)
+        header_data = yield stream.read_until(b"\r\n\r\n")
+        headers = HTTPHeaders.parse(native_str(header_data.decode("latin1")))
+        body = yield stream.read_bytes(int(headers["Content-Length"]))
+        self.assertEqual(body, b"Got 1024 bytes in POST")
+        stream.close()
+
+
+class EchoHandler(RequestHandler):
+    def get(self):
+        self.write(recursive_unicode(self.request.arguments))
+
+    def post(self):
+        self.write(recursive_unicode(self.request.arguments))
+
+
+class TypeCheckHandler(RequestHandler):
+    def prepare(self):
+        self.errors = {}  # type: Dict[str, str]
+        fields = [
+            ("method", str),
+            ("uri", str),
+            ("version", str),
+            ("remote_ip", str),
+            ("protocol", str),
+            ("host", str),
+            ("path", str),
+            ("query", str),
+        ]
+        for field, expected_type in fields:
+            self.check_type(field, getattr(self.request, field), expected_type)
+
+        self.check_type("header_key", list(self.request.headers.keys())[0], str)
+        self.check_type("header_value", list(self.request.headers.values())[0], str)
+
+        self.check_type("cookie_key", list(self.request.cookies.keys())[0], str)
+        self.check_type(
+            "cookie_value", list(self.request.cookies.values())[0].value, str
+        )
+        # secure cookies
+
+        self.check_type("arg_key", list(self.request.arguments.keys())[0], str)
+        self.check_type("arg_value", list(self.request.arguments.values())[0][0], bytes)
+
+    def post(self):
+        self.check_type("body", self.request.body, bytes)
+        self.write(self.errors)
+
+    def get(self):
+        self.write(self.errors)
+
+    def check_type(self, name, obj, expected_type):
+        actual_type = type(obj)
+        if expected_type != actual_type:
+            self.errors[name] = "expected %s, got %s" % (expected_type, actual_type)
+
+
+class PostEchoHandler(RequestHandler):
+    def post(self, *path_args):
+        self.write(dict(echo=self.get_argument("data")))
+
+
+class PostEchoGBKHandler(PostEchoHandler):
+    def decode_argument(self, value, name=None):
+        try:
+            return value.decode("gbk")
+        except Exception:
+            raise HTTPError(400, "invalid gbk bytes: %r" % value)
+
+
+class HTTPServerTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application(
+            [
+                ("/echo", EchoHandler),
+                ("/typecheck", TypeCheckHandler),
+                ("//doubleslash", EchoHandler),
+                ("/post_utf8", PostEchoHandler),
+                ("/post_gbk", PostEchoGBKHandler),
+            ]
+        )
+
+    def test_query_string_encoding(self):
+        response = self.fetch("/echo?foo=%C3%A9")
+        data = json_decode(response.body)
+        self.assertEqual(data, {"foo": ["\u00e9"]})
+
+    def test_empty_query_string(self):
+        response = self.fetch("/echo?foo=&foo=")
+        data = json_decode(response.body)
+        self.assertEqual(data, {"foo": ["", ""]})
+
+    def test_empty_post_parameters(self):
+        response = self.fetch("/echo", method="POST", body="foo=&bar=")
+        data = json_decode(response.body)
+        self.assertEqual(data, {"foo": [""], "bar": [""]})
+
+    def test_types(self):
+        headers = {"Cookie": "foo=bar"}
+        response = self.fetch("/typecheck?foo=bar", headers=headers)
+        data = json_decode(response.body)
+        self.assertEqual(data, {})
+
+        response = self.fetch(
+            "/typecheck", method="POST", body="foo=bar", headers=headers
+        )
+        data = json_decode(response.body)
+        self.assertEqual(data, {})
+
+    def test_double_slash(self):
+        # urlparse.urlsplit (which tornado.httpserver used to use
+        # incorrectly) would parse paths beginning with "//" as
+        # protocol-relative urls.
+        response = self.fetch("//doubleslash")
+        self.assertEqual(200, response.code)
+        self.assertEqual(json_decode(response.body), {})
+
+    def test_post_encodings(self):
+        headers = {"Content-Type": "application/x-www-form-urlencoded"}
+        uni_text = "chinese: \u5f20\u4e09"
+        for enc in ("utf8", "gbk"):
+            for quote in (True, False):
+                with self.subTest(enc=enc, quote=quote):
+                    bin_text = uni_text.encode(enc)
+                    if quote:
+                        bin_text = urllib.parse.quote(bin_text).encode("ascii")
+                    response = self.fetch(
+                        "/post_" + enc,
+                        method="POST",
+                        headers=headers,
+                        body=(b"data=" + bin_text),
+                    )
+                    self.assertEqual(json_decode(response.body), {"echo": uni_text})
+
+
+class HTTPServerRawTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application([("/echo", EchoHandler)])
+
+    def setUp(self):
+        super().setUp()
+        self.stream = IOStream(socket.socket())
+        self.io_loop.run_sync(
+            lambda: self.stream.connect(("127.0.0.1", self.get_http_port()))
+        )
+
+    def tearDown(self):
+        self.stream.close()
+        super().tearDown()
+
+    def test_empty_request(self):
+        self.stream.close()
+        self.io_loop.add_timeout(datetime.timedelta(seconds=0.001), self.stop)
+        self.wait()
+
+    def test_malformed_first_line_response(self):
+        with ExpectLog(gen_log, ".*Malformed HTTP request line", level=logging.INFO):
+            self.stream.write(b"asdf\r\n\r\n")
+            start_line, headers, response = self.io_loop.run_sync(
+                lambda: read_stream_body(self.stream)
+            )
+            self.assertEqual("HTTP/1.1", start_line.version)
+            self.assertEqual(400, start_line.code)
+            self.assertEqual("Bad Request", start_line.reason)
+
+    def test_malformed_first_line_log(self):
+        with ExpectLog(gen_log, ".*Malformed HTTP request line", level=logging.INFO):
+            self.stream.write(b"asdf\r\n\r\n")
+            # TODO: need an async version of ExpectLog so we don't need
+            # hard-coded timeouts here.
+            self.io_loop.add_timeout(datetime.timedelta(seconds=0.05), self.stop)
+            self.wait()
+
+    def test_malformed_headers(self):
+        with ExpectLog(
+            gen_log,
+            ".*Malformed HTTP message.*no colon in header line",
+            level=logging.INFO,
+        ):
+            self.stream.write(b"GET / HTTP/1.0\r\nasdf\r\n\r\n")
+            self.io_loop.add_timeout(datetime.timedelta(seconds=0.05), self.stop)
+            self.wait()
+
+    def test_chunked_request_body(self):
+        # Chunked requests are not widely supported and we don't have a way
+        # to generate them in AsyncHTTPClient, but HTTPServer will read them.
+        self.stream.write(
+            b"""\
+POST /echo HTTP/1.1
+Transfer-Encoding: chunked
+Content-Type: application/x-www-form-urlencoded
+
+4
+foo=
+3
+bar
+0
+
+""".replace(
+                b"\n", b"\r\n"
+            )
+        )
+        start_line, headers, response = self.io_loop.run_sync(
+            lambda: read_stream_body(self.stream)
+        )
+        self.assertEqual(json_decode(response), {"foo": ["bar"]})
+
+    def test_chunked_request_uppercase(self):
+        # As per RFC 2616 section 3.6, "Transfer-Encoding" header's value is
+        # case-insensitive.
+        self.stream.write(
+            b"""\
+POST /echo HTTP/1.1
+Transfer-Encoding: Chunked
+Content-Type: application/x-www-form-urlencoded
+
+4
+foo=
+3
+bar
+0
+
+""".replace(
+                b"\n", b"\r\n"
+            )
+        )
+        start_line, headers, response = self.io_loop.run_sync(
+            lambda: read_stream_body(self.stream)
+        )
+        self.assertEqual(json_decode(response), {"foo": ["bar"]})
+
+    @gen_test
+    def test_invalid_content_length(self):
+        with ExpectLog(
+            gen_log, ".*Only integer Content-Length is allowed", level=logging.INFO
+        ):
+            self.stream.write(
+                b"""\
+POST /echo HTTP/1.1
+Content-Length: foo
+
+bar
+
+""".replace(
+                    b"\n", b"\r\n"
+                )
+            )
+            yield self.stream.read_until_close()
+
+
+class XHeaderTest(HandlerBaseTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.set_header("request-version", self.request.version)
+            self.write(
+                dict(
+                    remote_ip=self.request.remote_ip,
+                    remote_protocol=self.request.protocol,
+                )
+            )
+
+    def get_httpserver_options(self):
+        return dict(xheaders=True, trusted_downstream=["5.5.5.5"])
+
+    def test_ip_headers(self):
+        self.assertEqual(self.fetch_json("/")["remote_ip"], "127.0.0.1")
+
+        valid_ipv4 = {"X-Real-IP": "4.4.4.4"}
+        self.assertEqual(
+            self.fetch_json("/", headers=valid_ipv4)["remote_ip"], "4.4.4.4"
+        )
+
+        valid_ipv4_list = {"X-Forwarded-For": "127.0.0.1, 4.4.4.4"}
+        self.assertEqual(
+            self.fetch_json("/", headers=valid_ipv4_list)["remote_ip"], "4.4.4.4"
+        )
+
+        valid_ipv6 = {"X-Real-IP": "2620:0:1cfe:face:b00c::3"}
+        self.assertEqual(
+            self.fetch_json("/", headers=valid_ipv6)["remote_ip"],
+            "2620:0:1cfe:face:b00c::3",
+        )
+
+        valid_ipv6_list = {"X-Forwarded-For": "::1, 2620:0:1cfe:face:b00c::3"}
+        self.assertEqual(
+            self.fetch_json("/", headers=valid_ipv6_list)["remote_ip"],
+            "2620:0:1cfe:face:b00c::3",
+        )
+
+        invalid_chars = {"X-Real-IP": "4.4.4.4<script>"}
+        self.assertEqual(
+            self.fetch_json("/", headers=invalid_chars)["remote_ip"], "127.0.0.1"
+        )
+
+        invalid_chars_list = {"X-Forwarded-For": "4.4.4.4, 5.5.5.5<script>"}
+        self.assertEqual(
+            self.fetch_json("/", headers=invalid_chars_list)["remote_ip"], "127.0.0.1"
+        )
+
+        invalid_host = {"X-Real-IP": "www.google.com"}
+        self.assertEqual(
+            self.fetch_json("/", headers=invalid_host)["remote_ip"], "127.0.0.1"
+        )
+
+    def test_trusted_downstream(self):
+        valid_ipv4_list = {"X-Forwarded-For": "127.0.0.1, 4.4.4.4, 5.5.5.5"}
+        resp = self.fetch("/", headers=valid_ipv4_list)
+        if resp.headers["request-version"].startswith("HTTP/2"):
+            # This is a hack - there's nothing that fundamentally requires http/1
+            # here but tornado_http2 doesn't support it yet.
+            self.skipTest("requires HTTP/1.x")
+        result = json_decode(resp.body)
+        self.assertEqual(result["remote_ip"], "4.4.4.4")
+
+    def test_scheme_headers(self):
+        self.assertEqual(self.fetch_json("/")["remote_protocol"], "http")
+
+        https_scheme = {"X-Scheme": "https"}
+        self.assertEqual(
+            self.fetch_json("/", headers=https_scheme)["remote_protocol"], "https"
+        )
+
+        https_forwarded = {"X-Forwarded-Proto": "https"}
+        self.assertEqual(
+            self.fetch_json("/", headers=https_forwarded)["remote_protocol"], "https"
+        )
+
+        https_multi_forwarded = {"X-Forwarded-Proto": "https , http"}
+        self.assertEqual(
+            self.fetch_json("/", headers=https_multi_forwarded)["remote_protocol"],
+            "http",
+        )
+
+        http_multi_forwarded = {"X-Forwarded-Proto": "http,https"}
+        self.assertEqual(
+            self.fetch_json("/", headers=http_multi_forwarded)["remote_protocol"],
+            "https",
+        )
+
+        bad_forwarded = {"X-Forwarded-Proto": "unknown"}
+        self.assertEqual(
+            self.fetch_json("/", headers=bad_forwarded)["remote_protocol"], "http"
+        )
+
+
+class SSLXHeaderTest(AsyncHTTPSTestCase, HandlerBaseTestCase):
+    def get_app(self):
+        return Application([("/", XHeaderTest.Handler)])
+
+    def get_httpserver_options(self):
+        output = super().get_httpserver_options()
+        output["xheaders"] = True
+        return output
+
+    def test_request_without_xprotocol(self):
+        self.assertEqual(self.fetch_json("/")["remote_protocol"], "https")
+
+        http_scheme = {"X-Scheme": "http"}
+        self.assertEqual(
+            self.fetch_json("/", headers=http_scheme)["remote_protocol"], "http"
+        )
+
+        bad_scheme = {"X-Scheme": "unknown"}
+        self.assertEqual(
+            self.fetch_json("/", headers=bad_scheme)["remote_protocol"], "https"
+        )
+
+
+class ManualProtocolTest(HandlerBaseTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.write(dict(protocol=self.request.protocol))
+
+    def get_httpserver_options(self):
+        return dict(protocol="https")
+
+    def test_manual_protocol(self):
+        self.assertEqual(self.fetch_json("/")["protocol"], "https")
+
+
+@unittest.skipIf(
+    not hasattr(socket, "AF_UNIX") or sys.platform == "cygwin",
+    "unix sockets not supported on this platform",
+)
+class UnixSocketTest(AsyncTestCase):
+    """HTTPServers can listen on Unix sockets too.
+
+    Why would you want to do this?  Nginx can proxy to backends listening
+    on unix sockets, for one thing (and managing a namespace for unix
+    sockets can be easier than managing a bunch of TCP port numbers).
+
+    Unfortunately, there's no way to specify a unix socket in a url for
+    an HTTP client, so we have to test this by hand.
+    """
+
+    def setUp(self):
+        super().setUp()
+        self.tmpdir = tempfile.mkdtemp()
+        self.sockfile = os.path.join(self.tmpdir, "test.sock")
+        sock = netutil.bind_unix_socket(self.sockfile)
+        app = Application([("/hello", HelloWorldRequestHandler)])
+        self.server = HTTPServer(app)
+        self.server.add_socket(sock)
+        self.stream = IOStream(socket.socket(socket.AF_UNIX))
+        self.io_loop.run_sync(lambda: self.stream.connect(self.sockfile))
+
+    def tearDown(self):
+        self.stream.close()
+        self.io_loop.run_sync(self.server.close_all_connections)
+        self.server.stop()
+        shutil.rmtree(self.tmpdir)
+        super().tearDown()
+
+    @gen_test
+    def test_unix_socket(self):
+        self.stream.write(b"GET /hello HTTP/1.0\r\n\r\n")
+        response = yield self.stream.read_until(b"\r\n")
+        self.assertEqual(response, b"HTTP/1.1 200 OK\r\n")
+        header_data = yield self.stream.read_until(b"\r\n\r\n")
+        headers = HTTPHeaders.parse(header_data.decode("latin1"))
+        body = yield self.stream.read_bytes(int(headers["Content-Length"]))
+        self.assertEqual(body, b"Hello world")
+
+    @gen_test
+    def test_unix_socket_bad_request(self):
+        # Unix sockets don't have remote addresses so they just return an
+        # empty string.
+        with ExpectLog(gen_log, "Malformed HTTP message from", level=logging.INFO):
+            self.stream.write(b"garbage\r\n\r\n")
+            response = yield self.stream.read_until_close()
+        self.assertEqual(response, b"HTTP/1.1 400 Bad Request\r\n\r\n")
+
+
+class KeepAliveTest(AsyncHTTPTestCase):
+    """Tests various scenarios for HTTP 1.1 keep-alive support.
+
+    These tests don't use AsyncHTTPClient because we want to control
+    connection reuse and closing.
+    """
+
+    def get_app(self):
+        class HelloHandler(RequestHandler):
+            def get(self):
+                self.finish("Hello world")
+
+            def post(self):
+                self.finish("Hello world")
+
+        class LargeHandler(RequestHandler):
+            def get(self):
+                # 512KB should be bigger than the socket buffers so it will
+                # be written out in chunks.
+                self.write("".join(chr(i % 256) * 1024 for i in range(512)))
+
+        class TransferEncodingChunkedHandler(RequestHandler):
+            @gen.coroutine
+            def head(self):
+                self.write("Hello world")
+                yield self.flush()
+
+        class FinishOnCloseHandler(RequestHandler):
+            def initialize(self, cleanup_event):
+                self.cleanup_event = cleanup_event
+
+            @gen.coroutine
+            def get(self):
+                self.flush()
+                yield self.cleanup_event.wait()
+
+            def on_connection_close(self):
+                # This is not very realistic, but finishing the request
+                # from the close callback has the right timing to mimic
+                # some errors seen in the wild.
+                self.finish("closed")
+
+        self.cleanup_event = Event()
+        return Application(
+            [
+                ("/", HelloHandler),
+                ("/large", LargeHandler),
+                ("/chunked", TransferEncodingChunkedHandler),
+                (
+                    "/finish_on_close",
+                    FinishOnCloseHandler,
+                    dict(cleanup_event=self.cleanup_event),
+                ),
+            ]
+        )
+
+    def setUp(self):
+        super().setUp()
+        self.http_version = b"HTTP/1.1"
+
+    def tearDown(self):
+        # We just closed the client side of the socket; let the IOLoop run
+        # once to make sure the server side got the message.
+        self.io_loop.add_timeout(datetime.timedelta(seconds=0.001), self.stop)
+        self.wait()
+
+        if hasattr(self, "stream"):
+            self.stream.close()
+        super().tearDown()
+
+    # The next few methods are a crude manual http client
+    @gen.coroutine
+    def connect(self):
+        self.stream = IOStream(socket.socket())
+        yield self.stream.connect(("127.0.0.1", self.get_http_port()))
+
+    @gen.coroutine
+    def read_headers(self):
+        first_line = yield self.stream.read_until(b"\r\n")
+        self.assertTrue(first_line.startswith(b"HTTP/1.1 200"), first_line)
+        header_bytes = yield self.stream.read_until(b"\r\n\r\n")
+        headers = HTTPHeaders.parse(header_bytes.decode("latin1"))
+        raise gen.Return(headers)
+
+    @gen.coroutine
+    def read_response(self):
+        self.headers = yield self.read_headers()
+        body = yield self.stream.read_bytes(int(self.headers["Content-Length"]))
+        self.assertEqual(b"Hello world", body)
+
+    def close(self):
+        self.stream.close()
+        del self.stream
+
+    @gen_test
+    def test_two_requests(self):
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.1\r\n\r\n")
+        yield self.read_response()
+        self.stream.write(b"GET / HTTP/1.1\r\n\r\n")
+        yield self.read_response()
+        self.close()
+
+    @gen_test
+    def test_request_close(self):
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.1\r\nConnection: close\r\n\r\n")
+        yield self.read_response()
+        data = yield self.stream.read_until_close()
+        self.assertTrue(not data)
+        self.assertEqual(self.headers["Connection"], "close")
+        self.close()
+
+    # keepalive is supported for http 1.0 too, but it's opt-in
+    @gen_test
+    def test_http10(self):
+        self.http_version = b"HTTP/1.0"
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.0\r\n\r\n")
+        yield self.read_response()
+        data = yield self.stream.read_until_close()
+        self.assertTrue(not data)
+        self.assertTrue("Connection" not in self.headers)
+        self.close()
+
+    @gen_test
+    def test_http10_keepalive(self):
+        self.http_version = b"HTTP/1.0"
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.0\r\nConnection: keep-alive\r\n\r\n")
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.stream.write(b"GET / HTTP/1.0\r\nConnection: keep-alive\r\n\r\n")
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.close()
+
+    @gen_test
+    def test_http10_keepalive_extra_crlf(self):
+        self.http_version = b"HTTP/1.0"
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.0\r\nConnection: keep-alive\r\n\r\n\r\n")
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.stream.write(b"GET / HTTP/1.0\r\nConnection: keep-alive\r\n\r\n")
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.close()
+
+    @gen_test
+    def test_pipelined_requests(self):
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.1\r\n\r\nGET / HTTP/1.1\r\n\r\n")
+        yield self.read_response()
+        yield self.read_response()
+        self.close()
+
+    @gen_test
+    def test_pipelined_cancel(self):
+        yield self.connect()
+        self.stream.write(b"GET / HTTP/1.1\r\n\r\nGET / HTTP/1.1\r\n\r\n")
+        # only read once
+        yield self.read_response()
+        self.close()
+
+    @gen_test
+    def test_cancel_during_download(self):
+        yield self.connect()
+        self.stream.write(b"GET /large HTTP/1.1\r\n\r\n")
+        yield self.read_headers()
+        yield self.stream.read_bytes(1024)
+        self.close()
+
+    @gen_test
+    def test_finish_while_closed(self):
+        yield self.connect()
+        self.stream.write(b"GET /finish_on_close HTTP/1.1\r\n\r\n")
+        yield self.read_headers()
+        self.close()
+        # Let the hanging coroutine clean up after itself
+        self.cleanup_event.set()
+
+    @gen_test
+    def test_keepalive_chunked(self):
+        self.http_version = b"HTTP/1.0"
+        yield self.connect()
+        self.stream.write(
+            b"POST / HTTP/1.0\r\n"
+            b"Connection: keep-alive\r\n"
+            b"Transfer-Encoding: chunked\r\n"
+            b"\r\n"
+            b"0\r\n"
+            b"\r\n"
+        )
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.stream.write(b"GET / HTTP/1.0\r\nConnection: keep-alive\r\n\r\n")
+        yield self.read_response()
+        self.assertEqual(self.headers["Connection"], "Keep-Alive")
+        self.close()
+
+    @gen_test
+    def test_keepalive_chunked_head_no_body(self):
+        yield self.connect()
+        self.stream.write(b"HEAD /chunked HTTP/1.1\r\n\r\n")
+        yield self.read_headers()
+
+        self.stream.write(b"HEAD /chunked HTTP/1.1\r\n\r\n")
+        yield self.read_headers()
+        self.close()
+
+
+class GzipBaseTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application([("/", EchoHandler)])
+
+    def post_gzip(self, body):
+        bytesio = BytesIO()
+        gzip_file = gzip.GzipFile(mode="w", fileobj=bytesio)
+        gzip_file.write(utf8(body))
+        gzip_file.close()
+        compressed_body = bytesio.getvalue()
+        return self.fetch(
+            "/",
+            method="POST",
+            body=compressed_body,
+            headers={"Content-Encoding": "gzip"},
+        )
+
+    def test_uncompressed(self):
+        response = self.fetch("/", method="POST", body="foo=bar")
+        self.assertEqual(json_decode(response.body), {"foo": ["bar"]})
+
+
+class GzipTest(GzipBaseTest, AsyncHTTPTestCase):
+    def get_httpserver_options(self):
+        return dict(decompress_request=True)
+
+    def test_gzip(self):
+        response = self.post_gzip("foo=bar")
+        self.assertEqual(json_decode(response.body), {"foo": ["bar"]})
+
+    def test_gzip_case_insensitive(self):
+        # https://datatracker.ietf.org/doc/html/rfc7231#section-3.1.2.1
+        bytesio = BytesIO()
+        gzip_file = gzip.GzipFile(mode="w", fileobj=bytesio)
+        gzip_file.write(utf8("foo=bar"))
+        gzip_file.close()
+        compressed_body = bytesio.getvalue()
+        response = self.fetch(
+            "/",
+            method="POST",
+            body=compressed_body,
+            headers={"Content-Encoding": "GZIP"},
+        )
+        self.assertEqual(json_decode(response.body), {"foo": ["bar"]})
+
+
+class GzipUnsupportedTest(GzipBaseTest, AsyncHTTPTestCase):
+    def test_gzip_unsupported(self):
+        # Gzip support is opt-in; without it the server fails to parse
+        # the body (but parsing form bodies is currently just a log message,
+        # not a fatal error).
+        with ExpectLog(gen_log, "Unsupported Content-Encoding"):
+            response = self.post_gzip("foo=bar")
+        self.assertEqual(json_decode(response.body), {})
+
+
+class StreamingChunkSizeTest(AsyncHTTPTestCase):
+    # 50 characters long, and repetitive so it can be compressed.
+    BODY = b"01234567890123456789012345678901234567890123456789"
+    CHUNK_SIZE = 16
+
+    def get_http_client(self):
+        # body_producer doesn't work on curl_httpclient, so override the
+        # configured AsyncHTTPClient implementation.
+        return SimpleAsyncHTTPClient()
+
+    def get_httpserver_options(self):
+        return dict(chunk_size=self.CHUNK_SIZE, decompress_request=True)
+
+    class MessageDelegate(HTTPMessageDelegate):
+        def __init__(self, connection):
+            self.connection = connection
+
+        def headers_received(self, start_line, headers):
+            self.chunk_lengths = []  # type: List[int]
+
+        def data_received(self, chunk):
+            self.chunk_lengths.append(len(chunk))
+
+        def finish(self):
+            response_body = utf8(json_encode(self.chunk_lengths))
+            self.connection.write_headers(
+                ResponseStartLine("HTTP/1.1", 200, "OK"),
+                HTTPHeaders({"Content-Length": str(len(response_body))}),
+            )
+            self.connection.write(response_body)
+            self.connection.finish()
+
+    def get_app(self):
+        class App(HTTPServerConnectionDelegate):
+            def start_request(self, server_conn, request_conn):
+                return StreamingChunkSizeTest.MessageDelegate(request_conn)
+
+        return App()
+
+    def fetch_chunk_sizes(self, **kwargs):
+        response = self.fetch("/", method="POST", **kwargs)
+        response.rethrow()
+        chunks = json_decode(response.body)
+        self.assertEqual(len(self.BODY), sum(chunks))
+        for chunk_size in chunks:
+            self.assertLessEqual(
+                chunk_size, self.CHUNK_SIZE, "oversized chunk: " + str(chunks)
+            )
+            self.assertGreater(chunk_size, 0, "empty chunk: " + str(chunks))
+        return chunks
+
+    def compress(self, body):
+        bytesio = BytesIO()
+        gzfile = gzip.GzipFile(mode="w", fileobj=bytesio)
+        gzfile.write(body)
+        gzfile.close()
+        compressed = bytesio.getvalue()
+        if len(compressed) >= len(body):
+            raise Exception("body did not shrink when compressed")
+        return compressed
+
+    def test_regular_body(self):
+        chunks = self.fetch_chunk_sizes(body=self.BODY)
+        # Without compression we know exactly what to expect.
+        self.assertEqual([16, 16, 16, 2], chunks)
+
+    def test_compressed_body(self):
+        self.fetch_chunk_sizes(
+            body=self.compress(self.BODY), headers={"Content-Encoding": "gzip"}
+        )
+        # Compression creates irregular boundaries so the assertions
+        # in fetch_chunk_sizes are as specific as we can get.
+
+    def test_chunked_body(self):
+        def body_producer(write):
+            write(self.BODY[:20])
+            write(self.BODY[20:])
+
+        chunks = self.fetch_chunk_sizes(body_producer=body_producer)
+        # HTTP chunk boundaries translate to application-visible breaks
+        self.assertEqual([16, 4, 16, 14], chunks)
+
+    def test_chunked_compressed(self):
+        compressed = self.compress(self.BODY)
+        self.assertGreater(len(compressed), 20)
+
+        def body_producer(write):
+            write(compressed[:20])
+            write(compressed[20:])
+
+        self.fetch_chunk_sizes(
+            body_producer=body_producer, headers={"Content-Encoding": "gzip"}
+        )
+
+
+class MaxHeaderSizeTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application([("/", HelloWorldRequestHandler)])
+
+    def get_httpserver_options(self):
+        return dict(max_header_size=1024)
+
+    def test_small_headers(self):
+        response = self.fetch("/", headers={"X-Filler": "a" * 100})
+        response.rethrow()
+        self.assertEqual(response.body, b"Hello world")
+
+    def test_large_headers(self):
+        with ExpectLog(gen_log, "Unsatisfiable read", required=False):
+            try:
+                self.fetch("/", headers={"X-Filler": "a" * 1000}, raise_error=True)
+                self.fail("did not raise expected exception")
+            except HTTPError as e:
+                # 431 is "Request Header Fields Too Large", defined in RFC
+                # 6585. However, many implementations just close the
+                # connection in this case, resulting in a missing response.
+                if e.response is not None:
+                    self.assertIn(e.response.code, (431, 599))
+
+
+@skipOnTravis
+class IdleTimeoutTest(AsyncHTTPTestCase):
+    def get_app(self):
+        return Application([("/", HelloWorldRequestHandler)])
+
+    def get_httpserver_options(self):
+        return dict(idle_connection_timeout=0.1)
+
+    def setUp(self):
+        super().setUp()
+        self.streams = []  # type: List[IOStream]
+
+    def tearDown(self):
+        super().tearDown()
+        for stream in self.streams:
+            stream.close()
+
+    @gen.coroutine
+    def connect(self):
+        stream = IOStream(socket.socket())
+        yield stream.connect(("127.0.0.1", self.get_http_port()))
+        self.streams.append(stream)
+        raise gen.Return(stream)
+
+    @gen_test
+    def test_unused_connection(self):
+        stream = yield self.connect()
+        event = Event()
+        stream.set_close_callback(event.set)
+        yield event.wait()
+
+    @gen_test
+    def test_idle_after_use(self):
+        stream = yield self.connect()
+        event = Event()
+        stream.set_close_callback(event.set)
+
+        # Use the connection twice to make sure keep-alives are working
+        for i in range(2):
+            stream.write(b"GET / HTTP/1.1\r\n\r\n")
+            yield stream.read_until(b"\r\n\r\n")
+            data = yield stream.read_bytes(11)
+            self.assertEqual(data, b"Hello world")
+
+        # Now let the timeout trigger and close the connection.
+        yield event.wait()
+
+
+class BodyLimitsTest(AsyncHTTPTestCase):
+    def get_app(self):
+        class BufferedHandler(RequestHandler):
+            def put(self):
+                self.write(str(len(self.request.body)))
+
+        @stream_request_body
+        class StreamingHandler(RequestHandler):
+            def initialize(self):
+                self.bytes_read = 0
+
+            def prepare(self):
+                conn = typing.cast(HTTP1Connection, self.request.connection)
+                if "expected_size" in self.request.arguments:
+                    conn.set_max_body_size(int(self.get_argument("expected_size")))
+                if "body_timeout" in self.request.arguments:
+                    conn.set_body_timeout(float(self.get_argument("body_timeout")))
+
+            def data_received(self, data):
+                self.bytes_read += len(data)
+
+            def put(self):
+                self.write(str(self.bytes_read))
+
+        return Application(
+            [("/buffered", BufferedHandler), ("/streaming", StreamingHandler)]
+        )
+
+    def get_httpserver_options(self):
+        return dict(body_timeout=3600, max_body_size=4096)
+
+    def get_http_client(self):
+        # body_producer doesn't work on curl_httpclient, so override the
+        # configured AsyncHTTPClient implementation.
+        return SimpleAsyncHTTPClient()
+
+    def test_small_body(self):
+        response = self.fetch("/buffered", method="PUT", body=b"a" * 4096)
+        self.assertEqual(response.body, b"4096")
+        response = self.fetch("/streaming", method="PUT", body=b"a" * 4096)
+        self.assertEqual(response.body, b"4096")
+
+    def test_large_body_buffered(self):
+        with ExpectLog(gen_log, ".*Content-Length too long", level=logging.INFO):
+            response = self.fetch("/buffered", method="PUT", body=b"a" * 10240)
+        self.assertEqual(response.code, 400)
+
+    @unittest.skipIf(os.name == "nt", "flaky on windows")
+    def test_large_body_buffered_chunked(self):
+        # This test is flaky on windows for unknown reasons.
+        with ExpectLog(gen_log, ".*chunked body too large", level=logging.INFO):
+            response = self.fetch(
+                "/buffered",
+                method="PUT",
+                body_producer=lambda write: write(b"a" * 10240),
+            )
+        self.assertEqual(response.code, 400)
+
+    def test_large_body_streaming(self):
+        with ExpectLog(gen_log, ".*Content-Length too long", level=logging.INFO):
+            response = self.fetch("/streaming", method="PUT", body=b"a" * 10240)
+        self.assertEqual(response.code, 400)
+
+    @unittest.skipIf(os.name == "nt", "flaky on windows")
+    def test_large_body_streaming_chunked(self):
+        with ExpectLog(gen_log, ".*chunked body too large", level=logging.INFO):
+            response = self.fetch(
+                "/streaming",
+                method="PUT",
+                body_producer=lambda write: write(b"a" * 10240),
+            )
+        self.assertEqual(response.code, 400)
+
+    def test_large_body_streaming_override(self):
+        response = self.fetch(
+            "/streaming?expected_size=10240", method="PUT", body=b"a" * 10240
+        )
+        self.assertEqual(response.body, b"10240")
+
+    def test_large_body_streaming_chunked_override(self):
+        response = self.fetch(
+            "/streaming?expected_size=10240",
+            method="PUT",
+            body_producer=lambda write: write(b"a" * 10240),
+        )
+        self.assertEqual(response.body, b"10240")
+
+    @gen_test
+    def test_timeout(self):
+        stream = IOStream(socket.socket())
+        try:
+            yield stream.connect(("127.0.0.1", self.get_http_port()))
+            # Use a raw stream because AsyncHTTPClient won't let us read a
+            # response without finishing a body.
+            stream.write(
+                b"PUT /streaming?body_timeout=0.1 HTTP/1.0\r\n"
+                b"Content-Length: 42\r\n\r\n"
+            )
+            with ExpectLog(gen_log, "Timeout reading body", level=logging.INFO):
+                response = yield stream.read_until_close()
+            self.assertEqual(response, b"")
+        finally:
+            stream.close()
+
+    @gen_test
+    def test_body_size_override_reset(self):
+        # The max_body_size override is reset between requests.
+        stream = IOStream(socket.socket())
+        try:
+            yield stream.connect(("127.0.0.1", self.get_http_port()))
+            # Use a raw stream so we can make sure it's all on one connection.
+            stream.write(
+                b"PUT /streaming?expected_size=10240 HTTP/1.1\r\n"
+                b"Content-Length: 10240\r\n\r\n"
+            )
+            stream.write(b"a" * 10240)
+            start_line, headers, response = yield read_stream_body(stream)
+            self.assertEqual(response, b"10240")
+            # Without the ?expected_size parameter, we get the old default value
+            stream.write(
+                b"PUT /streaming HTTP/1.1\r\n" b"Content-Length: 10240\r\n\r\n"
+            )
+            with ExpectLog(gen_log, ".*Content-Length too long", level=logging.INFO):
+                data = yield stream.read_until_close()
+            self.assertEqual(data, b"HTTP/1.1 400 Bad Request\r\n\r\n")
+        finally:
+            stream.close()
+
+
+class LegacyInterfaceTest(AsyncHTTPTestCase):
+    def get_app(self):
+        # The old request_callback interface does not implement the
+        # delegate interface, and writes its response via request.write
+        # instead of request.connection.write_headers.
+        def handle_request(request):
+            self.http1 = request.version.startswith("HTTP/1.")
+            if not self.http1:
+                # This test will be skipped if we're using HTTP/2,
+                # so just close it out cleanly using the modern interface.
+                request.connection.write_headers(
+                    ResponseStartLine("", 200, "OK"), HTTPHeaders()
+                )
+                request.connection.finish()
+                return
+            message = b"Hello world"
+            request.connection.write(
+                utf8("HTTP/1.1 200 OK\r\n" "Content-Length: %d\r\n\r\n" % len(message))
+            )
+            request.connection.write(message)
+            request.connection.finish()
+
+        return handle_request
+
+    def test_legacy_interface(self):
+        response = self.fetch("/")
+        if not self.http1:
+            self.skipTest("requires HTTP/1.x")
+        self.assertEqual(response.body, b"Hello world")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/httputil_test.py b/venv/lib/python3.9/site-packages/tornado/test/httputil_test.py
new file mode 100644
index 00000000..8424491d
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/httputil_test.py
@@ -0,0 +1,521 @@
+from tornado.httputil import (
+    url_concat,
+    parse_multipart_form_data,
+    HTTPHeaders,
+    format_timestamp,
+    HTTPServerRequest,
+    parse_request_start_line,
+    parse_cookie,
+    qs_to_qsl,
+    HTTPInputError,
+    HTTPFile,
+)
+from tornado.escape import utf8, native_str
+from tornado.log import gen_log
+from tornado.testing import ExpectLog
+
+import copy
+import datetime
+import logging
+import pickle
+import time
+import urllib.parse
+import unittest
+
+from typing import Tuple, Dict, List
+
+
+def form_data_args() -> Tuple[Dict[str, List[bytes]], Dict[str, List[HTTPFile]]]:
+    """Return two empty dicts suitable for use with parse_multipart_form_data.
+
+    mypy insists on type annotations for dict literals, so this lets us avoid
+    the verbose types throughout this test.
+    """
+    return {}, {}
+
+
+class TestUrlConcat(unittest.TestCase):
+    def test_url_concat_no_query_params(self):
+        url = url_concat("https://localhost/path", [("y", "y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?y=y&z=z")
+
+    def test_url_concat_encode_args(self):
+        url = url_concat("https://localhost/path", [("y", "/y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?y=%2Fy&z=z")
+
+    def test_url_concat_trailing_q(self):
+        url = url_concat("https://localhost/path?", [("y", "y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?y=y&z=z")
+
+    def test_url_concat_q_with_no_trailing_amp(self):
+        url = url_concat("https://localhost/path?x", [("y", "y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?x=&y=y&z=z")
+
+    def test_url_concat_trailing_amp(self):
+        url = url_concat("https://localhost/path?x&", [("y", "y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?x=&y=y&z=z")
+
+    def test_url_concat_mult_params(self):
+        url = url_concat("https://localhost/path?a=1&b=2", [("y", "y"), ("z", "z")])
+        self.assertEqual(url, "https://localhost/path?a=1&b=2&y=y&z=z")
+
+    def test_url_concat_no_params(self):
+        url = url_concat("https://localhost/path?r=1&t=2", [])
+        self.assertEqual(url, "https://localhost/path?r=1&t=2")
+
+    def test_url_concat_none_params(self):
+        url = url_concat("https://localhost/path?r=1&t=2", None)
+        self.assertEqual(url, "https://localhost/path?r=1&t=2")
+
+    def test_url_concat_with_frag(self):
+        url = url_concat("https://localhost/path#tab", [("y", "y")])
+        self.assertEqual(url, "https://localhost/path?y=y#tab")
+
+    def test_url_concat_multi_same_params(self):
+        url = url_concat("https://localhost/path", [("y", "y1"), ("y", "y2")])
+        self.assertEqual(url, "https://localhost/path?y=y1&y=y2")
+
+    def test_url_concat_multi_same_query_params(self):
+        url = url_concat("https://localhost/path?r=1&r=2", [("y", "y")])
+        self.assertEqual(url, "https://localhost/path?r=1&r=2&y=y")
+
+    def test_url_concat_dict_params(self):
+        url = url_concat("https://localhost/path", dict(y="y"))
+        self.assertEqual(url, "https://localhost/path?y=y")
+
+
+class QsParseTest(unittest.TestCase):
+    def test_parsing(self):
+        qsstring = "a=1&b=2&a=3"
+        qs = urllib.parse.parse_qs(qsstring)
+        qsl = list(qs_to_qsl(qs))
+        self.assertIn(("a", "1"), qsl)
+        self.assertIn(("a", "3"), qsl)
+        self.assertIn(("b", "2"), qsl)
+
+
+class MultipartFormDataTest(unittest.TestCase):
+    def test_file_upload(self):
+        data = b"""\
+--1234
+Content-Disposition: form-data; name="files"; filename="ab.txt"
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        parse_multipart_form_data(b"1234", data, args, files)
+        file = files["files"][0]
+        self.assertEqual(file["filename"], "ab.txt")
+        self.assertEqual(file["body"], b"Foo")
+
+    def test_unquoted_names(self):
+        # quotes are optional unless special characters are present
+        data = b"""\
+--1234
+Content-Disposition: form-data; name=files; filename=ab.txt
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        parse_multipart_form_data(b"1234", data, args, files)
+        file = files["files"][0]
+        self.assertEqual(file["filename"], "ab.txt")
+        self.assertEqual(file["body"], b"Foo")
+
+    def test_special_filenames(self):
+        filenames = [
+            "a;b.txt",
+            'a"b.txt',
+            'a";b.txt',
+            'a;"b.txt',
+            'a";";.txt',
+            'a\\"b.txt',
+            "a\\b.txt",
+        ]
+        for filename in filenames:
+            logging.debug("trying filename %r", filename)
+            str_data = """\
+--1234
+Content-Disposition: form-data; name="files"; filename="%s"
+
+Foo
+--1234--""" % filename.replace(
+                "\\", "\\\\"
+            ).replace(
+                '"', '\\"'
+            )
+            data = utf8(str_data.replace("\n", "\r\n"))
+            args, files = form_data_args()
+            parse_multipart_form_data(b"1234", data, args, files)
+            file = files["files"][0]
+            self.assertEqual(file["filename"], filename)
+            self.assertEqual(file["body"], b"Foo")
+
+    def test_non_ascii_filename(self):
+        data = b"""\
+--1234
+Content-Disposition: form-data; name="files"; filename="ab.txt"; filename*=UTF-8''%C3%A1b.txt
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        parse_multipart_form_data(b"1234", data, args, files)
+        file = files["files"][0]
+        self.assertEqual(file["filename"], "áb.txt")
+        self.assertEqual(file["body"], b"Foo")
+
+    def test_boundary_starts_and_ends_with_quotes(self):
+        data = b"""\
+--1234
+Content-Disposition: form-data; name="files"; filename="ab.txt"
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        parse_multipart_form_data(b'"1234"', data, args, files)
+        file = files["files"][0]
+        self.assertEqual(file["filename"], "ab.txt")
+        self.assertEqual(file["body"], b"Foo")
+
+    def test_missing_headers(self):
+        data = b"""\
+--1234
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        with ExpectLog(gen_log, "multipart/form-data missing headers"):
+            parse_multipart_form_data(b"1234", data, args, files)
+        self.assertEqual(files, {})
+
+    def test_invalid_content_disposition(self):
+        data = b"""\
+--1234
+Content-Disposition: invalid; name="files"; filename="ab.txt"
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        with ExpectLog(gen_log, "Invalid multipart/form-data"):
+            parse_multipart_form_data(b"1234", data, args, files)
+        self.assertEqual(files, {})
+
+    def test_line_does_not_end_with_correct_line_break(self):
+        data = b"""\
+--1234
+Content-Disposition: form-data; name="files"; filename="ab.txt"
+
+Foo--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        with ExpectLog(gen_log, "Invalid multipart/form-data"):
+            parse_multipart_form_data(b"1234", data, args, files)
+        self.assertEqual(files, {})
+
+    def test_content_disposition_header_without_name_parameter(self):
+        data = b"""\
+--1234
+Content-Disposition: form-data; filename="ab.txt"
+
+Foo
+--1234--""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        with ExpectLog(gen_log, "multipart/form-data value missing name"):
+            parse_multipart_form_data(b"1234", data, args, files)
+        self.assertEqual(files, {})
+
+    def test_data_after_final_boundary(self):
+        # The spec requires that data after the final boundary be ignored.
+        # http://www.w3.org/Protocols/rfc1341/7_2_Multipart.html
+        # In practice, some libraries include an extra CRLF after the boundary.
+        data = b"""\
+--1234
+Content-Disposition: form-data; name="files"; filename="ab.txt"
+
+Foo
+--1234--
+""".replace(
+            b"\n", b"\r\n"
+        )
+        args, files = form_data_args()
+        parse_multipart_form_data(b"1234", data, args, files)
+        file = files["files"][0]
+        self.assertEqual(file["filename"], "ab.txt")
+        self.assertEqual(file["body"], b"Foo")
+
+
+class HTTPHeadersTest(unittest.TestCase):
+    def test_multi_line(self):
+        # Lines beginning with whitespace are appended to the previous line
+        # with any leading whitespace replaced by a single space.
+        # Note that while multi-line headers are a part of the HTTP spec,
+        # their use is strongly discouraged.
+        data = """\
+Foo: bar
+ baz
+Asdf: qwer
+\tzxcv
+Foo: even
+     more
+     lines
+""".replace(
+            "\n", "\r\n"
+        )
+        headers = HTTPHeaders.parse(data)
+        self.assertEqual(headers["asdf"], "qwer zxcv")
+        self.assertEqual(headers.get_list("asdf"), ["qwer zxcv"])
+        self.assertEqual(headers["Foo"], "bar baz,even more lines")
+        self.assertEqual(headers.get_list("foo"), ["bar baz", "even more lines"])
+        self.assertEqual(
+            sorted(list(headers.get_all())),
+            [("Asdf", "qwer zxcv"), ("Foo", "bar baz"), ("Foo", "even more lines")],
+        )
+
+    def test_malformed_continuation(self):
+        # If the first line starts with whitespace, it's a
+        # continuation line with nothing to continue, so reject it
+        # (with a proper error).
+        data = " Foo: bar"
+        self.assertRaises(HTTPInputError, HTTPHeaders.parse, data)
+
+    def test_unicode_newlines(self):
+        # Ensure that only \r\n is recognized as a header separator, and not
+        # the other newline-like unicode characters.
+        # Characters that are likely to be problematic can be found in
+        # http://unicode.org/standard/reports/tr13/tr13-5.html
+        # and cpython's unicodeobject.c (which defines the implementation
+        # of unicode_type.splitlines(), and uses a different list than TR13).
+        newlines = [
+            "\u001b",  # VERTICAL TAB
+            "\u001c",  # FILE SEPARATOR
+            "\u001d",  # GROUP SEPARATOR
+            "\u001e",  # RECORD SEPARATOR
+            "\u0085",  # NEXT LINE
+            "\u2028",  # LINE SEPARATOR
+            "\u2029",  # PARAGRAPH SEPARATOR
+        ]
+        for newline in newlines:
+            # Try the utf8 and latin1 representations of each newline
+            for encoding in ["utf8", "latin1"]:
+                try:
+                    try:
+                        encoded = newline.encode(encoding)
+                    except UnicodeEncodeError:
+                        # Some chars cannot be represented in latin1
+                        continue
+                    data = b"Cookie: foo=" + encoded + b"bar"
+                    # parse() wants a native_str, so decode through latin1
+                    # in the same way the real parser does.
+                    headers = HTTPHeaders.parse(native_str(data.decode("latin1")))
+                    expected = [
+                        (
+                            "Cookie",
+                            "foo=" + native_str(encoded.decode("latin1")) + "bar",
+                        )
+                    ]
+                    self.assertEqual(expected, list(headers.get_all()))
+                except Exception:
+                    gen_log.warning("failed while trying %r in %s", newline, encoding)
+                    raise
+
+    def test_optional_cr(self):
+        # Both CRLF and LF should be accepted as separators. CR should not be
+        # part of the data when followed by LF, but it is a normal char
+        # otherwise (or should bare CR be an error?)
+        headers = HTTPHeaders.parse("CRLF: crlf\r\nLF: lf\nCR: cr\rMore: more\r\n")
+        self.assertEqual(
+            sorted(headers.get_all()),
+            [("Cr", "cr\rMore: more"), ("Crlf", "crlf"), ("Lf", "lf")],
+        )
+
+    def test_copy(self):
+        all_pairs = [("A", "1"), ("A", "2"), ("B", "c")]
+        h1 = HTTPHeaders()
+        for k, v in all_pairs:
+            h1.add(k, v)
+        h2 = h1.copy()
+        h3 = copy.copy(h1)
+        h4 = copy.deepcopy(h1)
+        for headers in [h1, h2, h3, h4]:
+            # All the copies are identical, no matter how they were
+            # constructed.
+            self.assertEqual(list(sorted(headers.get_all())), all_pairs)
+        for headers in [h2, h3, h4]:
+            # Neither the dict or its member lists are reused.
+            self.assertIsNot(headers, h1)
+            self.assertIsNot(headers.get_list("A"), h1.get_list("A"))
+
+    def test_pickle_roundtrip(self):
+        headers = HTTPHeaders()
+        headers.add("Set-Cookie", "a=b")
+        headers.add("Set-Cookie", "c=d")
+        headers.add("Content-Type", "text/html")
+        pickled = pickle.dumps(headers)
+        unpickled = pickle.loads(pickled)
+        self.assertEqual(sorted(headers.get_all()), sorted(unpickled.get_all()))
+        self.assertEqual(sorted(headers.items()), sorted(unpickled.items()))
+
+    def test_setdefault(self):
+        headers = HTTPHeaders()
+        headers["foo"] = "bar"
+        # If a value is present, setdefault returns it without changes.
+        self.assertEqual(headers.setdefault("foo", "baz"), "bar")
+        self.assertEqual(headers["foo"], "bar")
+        # If a value is not present, setdefault sets it for future use.
+        self.assertEqual(headers.setdefault("quux", "xyzzy"), "xyzzy")
+        self.assertEqual(headers["quux"], "xyzzy")
+        self.assertEqual(sorted(headers.get_all()), [("Foo", "bar"), ("Quux", "xyzzy")])
+
+    def test_string(self):
+        headers = HTTPHeaders()
+        headers.add("Foo", "1")
+        headers.add("Foo", "2")
+        headers.add("Foo", "3")
+        headers2 = HTTPHeaders.parse(str(headers))
+        self.assertEqual(headers, headers2)
+
+
+class FormatTimestampTest(unittest.TestCase):
+    # Make sure that all the input types are supported.
+    TIMESTAMP = 1359312200.503611
+    EXPECTED = "Sun, 27 Jan 2013 18:43:20 GMT"
+
+    def check(self, value):
+        self.assertEqual(format_timestamp(value), self.EXPECTED)
+
+    def test_unix_time_float(self):
+        self.check(self.TIMESTAMP)
+
+    def test_unix_time_int(self):
+        self.check(int(self.TIMESTAMP))
+
+    def test_struct_time(self):
+        self.check(time.gmtime(self.TIMESTAMP))
+
+    def test_time_tuple(self):
+        tup = tuple(time.gmtime(self.TIMESTAMP))
+        self.assertEqual(9, len(tup))
+        self.check(tup)
+
+    def test_datetime(self):
+        self.check(datetime.datetime.utcfromtimestamp(self.TIMESTAMP))
+
+
+# HTTPServerRequest is mainly tested incidentally to the server itself,
+# but this tests the parts of the class that can be tested in isolation.
+class HTTPServerRequestTest(unittest.TestCase):
+    def test_default_constructor(self):
+        # All parameters are formally optional, but uri is required
+        # (and has been for some time).  This test ensures that no
+        # more required parameters slip in.
+        HTTPServerRequest(uri="/")
+
+    def test_body_is_a_byte_string(self):
+        requets = HTTPServerRequest(uri="/")
+        self.assertIsInstance(requets.body, bytes)
+
+    def test_repr_does_not_contain_headers(self):
+        request = HTTPServerRequest(
+            uri="/", headers=HTTPHeaders({"Canary": ["Coal Mine"]})
+        )
+        self.assertTrue("Canary" not in repr(request))
+
+
+class ParseRequestStartLineTest(unittest.TestCase):
+    METHOD = "GET"
+    PATH = "/foo"
+    VERSION = "HTTP/1.1"
+
+    def test_parse_request_start_line(self):
+        start_line = " ".join([self.METHOD, self.PATH, self.VERSION])
+        parsed_start_line = parse_request_start_line(start_line)
+        self.assertEqual(parsed_start_line.method, self.METHOD)
+        self.assertEqual(parsed_start_line.path, self.PATH)
+        self.assertEqual(parsed_start_line.version, self.VERSION)
+
+
+class ParseCookieTest(unittest.TestCase):
+    # These tests copied from Django:
+    # https://github.com/django/django/pull/6277/commits/da810901ada1cae9fc1f018f879f11a7fb467b28
+    def test_python_cookies(self):
+        """
+        Test cases copied from Python's Lib/test/test_http_cookies.py
+        """
+        self.assertEqual(
+            parse_cookie("chips=ahoy; vienna=finger"),
+            {"chips": "ahoy", "vienna": "finger"},
+        )
+        # Here parse_cookie() differs from Python's cookie parsing in that it
+        # treats all semicolons as delimiters, even within quotes.
+        self.assertEqual(
+            parse_cookie('keebler="E=mc2; L=\\"Loves\\"; fudge=\\012;"'),
+            {"keebler": '"E=mc2', "L": '\\"Loves\\"', "fudge": "\\012", "": '"'},
+        )
+        # Illegal cookies that have an '=' char in an unquoted value.
+        self.assertEqual(parse_cookie("keebler=E=mc2"), {"keebler": "E=mc2"})
+        # Cookies with ':' character in their name.
+        self.assertEqual(
+            parse_cookie("key:term=value:term"), {"key:term": "value:term"}
+        )
+        # Cookies with '[' and ']'.
+        self.assertEqual(
+            parse_cookie("a=b; c=[; d=r; f=h"), {"a": "b", "c": "[", "d": "r", "f": "h"}
+        )
+
+    def test_cookie_edgecases(self):
+        # Cookies that RFC6265 allows.
+        self.assertEqual(
+            parse_cookie("a=b; Domain=example.com"), {"a": "b", "Domain": "example.com"}
+        )
+        # parse_cookie() has historically kept only the last cookie with the
+        # same name.
+        self.assertEqual(parse_cookie("a=b; h=i; a=c"), {"a": "c", "h": "i"})
+
+    def test_invalid_cookies(self):
+        """
+        Cookie strings that go against RFC6265 but browsers will send if set
+        via document.cookie.
+        """
+        # Chunks without an equals sign appear as unnamed values per
+        # https://bugzilla.mozilla.org/show_bug.cgi?id=169091
+        self.assertIn(
+            "django_language",
+            parse_cookie("abc=def; unnamed; django_language=en").keys(),
+        )
+        # Even a double quote may be an unamed value.
+        self.assertEqual(parse_cookie('a=b; "; c=d'), {"a": "b", "": '"', "c": "d"})
+        # Spaces in names and values, and an equals sign in values.
+        self.assertEqual(
+            parse_cookie("a b c=d e = f; gh=i"), {"a b c": "d e = f", "gh": "i"}
+        )
+        # More characters the spec forbids.
+        self.assertEqual(
+            parse_cookie('a   b,c<>@:/[]?{}=d  "  =e,f g'),
+            {"a   b,c<>@:/[]?{}": 'd  "  =e,f g'},
+        )
+        # Unicode characters. The spec only allows ASCII.
+        self.assertEqual(
+            parse_cookie("saint=André Bessette"),
+            {"saint": native_str("André Bessette")},
+        )
+        # Browsers don't send extra whitespace or semicolons in Cookie headers,
+        # but parse_cookie() should parse whitespace the same way
+        # document.cookie parses whitespace.
+        self.assertEqual(
+            parse_cookie("  =  b  ;  ;  =  ;   c  =  ;  "), {"": "b", "c": ""}
+        )
diff --git a/venv/lib/python3.9/site-packages/tornado/test/import_test.py b/venv/lib/python3.9/site-packages/tornado/test/import_test.py
new file mode 100644
index 00000000..1ff52206
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/import_test.py
@@ -0,0 +1,65 @@
+# flake8: noqa
+import subprocess
+import sys
+import unittest
+
+_import_everything = b"""
+# The event loop is not fork-safe, and it's easy to initialize an asyncio.Future
+# at startup, which in turn creates the default event loop and prevents forking.
+# Explicitly disallow the default event loop so that an error will be raised
+# if something tries to touch it.
+import asyncio
+asyncio.set_event_loop(None)
+
+import importlib
+import tornado
+
+for mod in tornado.__all__:
+    if mod == "curl_httpclient":
+        # This module has extra dependencies; skip it if they're not installed.
+        try:
+            import pycurl
+        except ImportError:
+            continue
+    importlib.import_module(f"tornado.{mod}")
+"""
+
+_import_lazy = b"""
+import sys
+import tornado
+
+if "tornado.web" in sys.modules:
+    raise Exception("unexpected eager import")
+
+# Trigger a lazy import by referring to something in a submodule.
+tornado.web.RequestHandler
+
+if "tornado.web" not in sys.modules:
+    raise Exception("lazy import did not update sys.modules")
+"""
+
+
+class ImportTest(unittest.TestCase):
+    def test_import_everything(self):
+        # Test that all Tornado modules can be imported without side effects,
+        # specifically without initializing the default asyncio event loop.
+        # Since we can't tell which modules may have already beein imported
+        # in our process, do it in a subprocess for a clean slate.
+        proc = subprocess.Popen([sys.executable], stdin=subprocess.PIPE)
+        proc.communicate(_import_everything)
+        self.assertEqual(proc.returncode, 0)
+
+    def test_lazy_import(self):
+        # Test that submodules can be referenced lazily after "import tornado"
+        proc = subprocess.Popen([sys.executable], stdin=subprocess.PIPE)
+        proc.communicate(_import_lazy)
+        self.assertEqual(proc.returncode, 0)
+
+    def test_import_aliases(self):
+        # Ensure we don't delete formerly-documented aliases accidentally.
+        import tornado
+        import asyncio
+
+        self.assertIs(tornado.ioloop.TimeoutError, tornado.util.TimeoutError)
+        self.assertIs(tornado.gen.TimeoutError, tornado.util.TimeoutError)
+        self.assertIs(tornado.util.TimeoutError, asyncio.TimeoutError)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/ioloop_test.py b/venv/lib/python3.9/site-packages/tornado/test/ioloop_test.py
new file mode 100644
index 00000000..7de392f8
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/ioloop_test.py
@@ -0,0 +1,795 @@
+import asyncio
+from concurrent.futures import ThreadPoolExecutor
+from concurrent import futures
+from collections.abc import Generator
+import contextlib
+import datetime
+import functools
+import socket
+import subprocess
+import sys
+import threading
+import time
+import types
+from unittest import mock
+import unittest
+
+from tornado.escape import native_str
+from tornado import gen
+from tornado.ioloop import IOLoop, TimeoutError, PeriodicCallback
+from tornado.log import app_log
+from tornado.testing import (
+    AsyncTestCase,
+    bind_unused_port,
+    ExpectLog,
+    gen_test,
+    setup_with_context_manager,
+)
+from tornado.test.util import (
+    ignore_deprecation,
+    skipIfNonUnix,
+    skipOnTravis,
+)
+from tornado.concurrent import Future
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import List  # noqa: F401
+
+
+class TestIOLoop(AsyncTestCase):
+    def test_add_callback_return_sequence(self):
+        # A callback returning {} or [] shouldn't spin the CPU, see Issue #1803.
+        self.calls = 0
+
+        loop = self.io_loop
+        test = self
+        old_add_callback = loop.add_callback
+
+        def add_callback(self, callback, *args, **kwargs):
+            test.calls += 1
+            old_add_callback(callback, *args, **kwargs)
+
+        loop.add_callback = types.MethodType(add_callback, loop)  # type: ignore
+        loop.add_callback(lambda: {})  # type: ignore
+        loop.add_callback(lambda: [])  # type: ignore
+        loop.add_timeout(datetime.timedelta(milliseconds=50), loop.stop)
+        loop.start()
+        self.assertLess(self.calls, 10)
+
+    @skipOnTravis
+    def test_add_callback_wakeup(self):
+        # Make sure that add_callback from inside a running IOLoop
+        # wakes up the IOLoop immediately instead of waiting for a timeout.
+        def callback():
+            self.called = True
+            self.stop()
+
+        def schedule_callback():
+            self.called = False
+            self.io_loop.add_callback(callback)
+            # Store away the time so we can check if we woke up immediately
+            self.start_time = time.time()
+
+        self.io_loop.add_timeout(self.io_loop.time(), schedule_callback)
+        self.wait()
+        self.assertAlmostEqual(time.time(), self.start_time, places=2)
+        self.assertTrue(self.called)
+
+    @skipOnTravis
+    def test_add_callback_wakeup_other_thread(self):
+        def target():
+            # sleep a bit to let the ioloop go into its poll loop
+            time.sleep(0.01)
+            self.stop_time = time.time()
+            self.io_loop.add_callback(self.stop)
+
+        thread = threading.Thread(target=target)
+        self.io_loop.add_callback(thread.start)
+        self.wait()
+        delta = time.time() - self.stop_time
+        self.assertLess(delta, 0.1)
+        thread.join()
+
+    def test_add_timeout_timedelta(self):
+        self.io_loop.add_timeout(datetime.timedelta(microseconds=1), self.stop)
+        self.wait()
+
+    def test_multiple_add(self):
+        sock, port = bind_unused_port()
+        try:
+            self.io_loop.add_handler(
+                sock.fileno(), lambda fd, events: None, IOLoop.READ
+            )
+            # Attempting to add the same handler twice fails
+            # (with a platform-dependent exception)
+            self.assertRaises(
+                Exception,
+                self.io_loop.add_handler,
+                sock.fileno(),
+                lambda fd, events: None,
+                IOLoop.READ,
+            )
+        finally:
+            self.io_loop.remove_handler(sock.fileno())
+            sock.close()
+
+    def test_remove_without_add(self):
+        # remove_handler should not throw an exception if called on an fd
+        # was never added.
+        sock, port = bind_unused_port()
+        try:
+            self.io_loop.remove_handler(sock.fileno())
+        finally:
+            sock.close()
+
+    def test_add_callback_from_signal(self):
+        # cheat a little bit and just run this normally, since we can't
+        # easily simulate the races that happen with real signal handlers
+        self.io_loop.add_callback_from_signal(self.stop)
+        self.wait()
+
+    def test_add_callback_from_signal_other_thread(self):
+        # Very crude test, just to make sure that we cover this case.
+        # This also happens to be the first test where we run an IOLoop in
+        # a non-main thread.
+        other_ioloop = IOLoop()
+        thread = threading.Thread(target=other_ioloop.start)
+        thread.start()
+        other_ioloop.add_callback_from_signal(other_ioloop.stop)
+        thread.join()
+        other_ioloop.close()
+
+    def test_add_callback_while_closing(self):
+        # add_callback should not fail if it races with another thread
+        # closing the IOLoop. The callbacks are dropped silently
+        # without executing.
+        closing = threading.Event()
+
+        def target():
+            other_ioloop.add_callback(other_ioloop.stop)
+            other_ioloop.start()
+            closing.set()
+            other_ioloop.close(all_fds=True)
+
+        other_ioloop = IOLoop()
+        thread = threading.Thread(target=target)
+        thread.start()
+        closing.wait()
+        for i in range(1000):
+            other_ioloop.add_callback(lambda: None)
+
+    @skipIfNonUnix  # just because socketpair is so convenient
+    def test_read_while_writeable(self):
+        # Ensure that write events don't come in while we're waiting for
+        # a read and haven't asked for writeability. (the reverse is
+        # difficult to test for)
+        client, server = socket.socketpair()
+        try:
+
+            def handler(fd, events):
+                self.assertEqual(events, IOLoop.READ)
+                self.stop()
+
+            self.io_loop.add_handler(client.fileno(), handler, IOLoop.READ)
+            self.io_loop.add_timeout(
+                self.io_loop.time() + 0.01, functools.partial(server.send, b"asdf")
+            )
+            self.wait()
+            self.io_loop.remove_handler(client.fileno())
+        finally:
+            client.close()
+            server.close()
+
+    def test_remove_timeout_after_fire(self):
+        # It is not an error to call remove_timeout after it has run.
+        handle = self.io_loop.add_timeout(self.io_loop.time(), self.stop)
+        self.wait()
+        self.io_loop.remove_timeout(handle)
+
+    def test_remove_timeout_cleanup(self):
+        # Add and remove enough callbacks to trigger cleanup.
+        # Not a very thorough test, but it ensures that the cleanup code
+        # gets executed and doesn't blow up.  This test is only really useful
+        # on PollIOLoop subclasses, but it should run silently on any
+        # implementation.
+        for i in range(2000):
+            timeout = self.io_loop.add_timeout(self.io_loop.time() + 3600, lambda: None)
+            self.io_loop.remove_timeout(timeout)
+        # HACK: wait two IOLoop iterations for the GC to happen.
+        self.io_loop.add_callback(lambda: self.io_loop.add_callback(self.stop))
+        self.wait()
+
+    def test_remove_timeout_from_timeout(self):
+        calls = [False, False]
+
+        # Schedule several callbacks and wait for them all to come due at once.
+        # t2 should be cancelled by t1, even though it is already scheduled to
+        # be run before the ioloop even looks at it.
+        now = self.io_loop.time()
+
+        def t1():
+            calls[0] = True
+            self.io_loop.remove_timeout(t2_handle)
+
+        self.io_loop.add_timeout(now + 0.01, t1)
+
+        def t2():
+            calls[1] = True
+
+        t2_handle = self.io_loop.add_timeout(now + 0.02, t2)
+        self.io_loop.add_timeout(now + 0.03, self.stop)
+        time.sleep(0.03)
+        self.wait()
+        self.assertEqual(calls, [True, False])
+
+    def test_timeout_with_arguments(self):
+        # This tests that all the timeout methods pass through *args correctly.
+        results = []  # type: List[int]
+        self.io_loop.add_timeout(self.io_loop.time(), results.append, 1)
+        self.io_loop.add_timeout(datetime.timedelta(seconds=0), results.append, 2)
+        self.io_loop.call_at(self.io_loop.time(), results.append, 3)
+        self.io_loop.call_later(0, results.append, 4)
+        self.io_loop.call_later(0, self.stop)
+        self.wait()
+        # The asyncio event loop does not guarantee the order of these
+        # callbacks.
+        self.assertEqual(sorted(results), [1, 2, 3, 4])
+
+    def test_add_timeout_return(self):
+        # All the timeout methods return non-None handles that can be
+        # passed to remove_timeout.
+        handle = self.io_loop.add_timeout(self.io_loop.time(), lambda: None)
+        self.assertFalse(handle is None)
+        self.io_loop.remove_timeout(handle)
+
+    def test_call_at_return(self):
+        handle = self.io_loop.call_at(self.io_loop.time(), lambda: None)
+        self.assertFalse(handle is None)
+        self.io_loop.remove_timeout(handle)
+
+    def test_call_later_return(self):
+        handle = self.io_loop.call_later(0, lambda: None)
+        self.assertFalse(handle is None)
+        self.io_loop.remove_timeout(handle)
+
+    def test_close_file_object(self):
+        """When a file object is used instead of a numeric file descriptor,
+        the object should be closed (by IOLoop.close(all_fds=True),
+        not just the fd.
+        """
+        # Use a socket since they are supported by IOLoop on all platforms.
+        # Unfortunately, sockets don't support the .closed attribute for
+        # inspecting their close status, so we must use a wrapper.
+        class SocketWrapper(object):
+            def __init__(self, sockobj):
+                self.sockobj = sockobj
+                self.closed = False
+
+            def fileno(self):
+                return self.sockobj.fileno()
+
+            def close(self):
+                self.closed = True
+                self.sockobj.close()
+
+        sockobj, port = bind_unused_port()
+        socket_wrapper = SocketWrapper(sockobj)
+        io_loop = IOLoop()
+        io_loop.add_handler(socket_wrapper, lambda fd, events: None, IOLoop.READ)
+        io_loop.close(all_fds=True)
+        self.assertTrue(socket_wrapper.closed)
+
+    def test_handler_callback_file_object(self):
+        """The handler callback receives the same fd object it passed in."""
+        server_sock, port = bind_unused_port()
+        fds = []
+
+        def handle_connection(fd, events):
+            fds.append(fd)
+            conn, addr = server_sock.accept()
+            conn.close()
+            self.stop()
+
+        self.io_loop.add_handler(server_sock, handle_connection, IOLoop.READ)
+        with contextlib.closing(socket.socket()) as client_sock:
+            client_sock.connect(("127.0.0.1", port))
+            self.wait()
+        self.io_loop.remove_handler(server_sock)
+        self.io_loop.add_handler(server_sock.fileno(), handle_connection, IOLoop.READ)
+        with contextlib.closing(socket.socket()) as client_sock:
+            client_sock.connect(("127.0.0.1", port))
+            self.wait()
+        self.assertIs(fds[0], server_sock)
+        self.assertEqual(fds[1], server_sock.fileno())
+        self.io_loop.remove_handler(server_sock.fileno())
+        server_sock.close()
+
+    def test_mixed_fd_fileobj(self):
+        server_sock, port = bind_unused_port()
+
+        def f(fd, events):
+            pass
+
+        self.io_loop.add_handler(server_sock, f, IOLoop.READ)
+        with self.assertRaises(Exception):
+            # The exact error is unspecified - some implementations use
+            # IOError, others use ValueError.
+            self.io_loop.add_handler(server_sock.fileno(), f, IOLoop.READ)
+        self.io_loop.remove_handler(server_sock.fileno())
+        server_sock.close()
+
+    def test_reentrant(self):
+        """Calling start() twice should raise an error, not deadlock."""
+        returned_from_start = [False]
+        got_exception = [False]
+
+        def callback():
+            try:
+                self.io_loop.start()
+                returned_from_start[0] = True
+            except Exception:
+                got_exception[0] = True
+            self.stop()
+
+        self.io_loop.add_callback(callback)
+        self.wait()
+        self.assertTrue(got_exception[0])
+        self.assertFalse(returned_from_start[0])
+
+    def test_exception_logging(self):
+        """Uncaught exceptions get logged by the IOLoop."""
+        self.io_loop.add_callback(lambda: 1 / 0)
+        self.io_loop.add_callback(self.stop)
+        with ExpectLog(app_log, "Exception in callback"):
+            self.wait()
+
+    def test_exception_logging_future(self):
+        """The IOLoop examines exceptions from Futures and logs them."""
+
+        @gen.coroutine
+        def callback():
+            self.io_loop.add_callback(self.stop)
+            1 / 0
+
+        self.io_loop.add_callback(callback)
+        with ExpectLog(app_log, "Exception in callback"):
+            self.wait()
+
+    def test_exception_logging_native_coro(self):
+        """The IOLoop examines exceptions from awaitables and logs them."""
+
+        async def callback():
+            # Stop the IOLoop two iterations after raising an exception
+            # to give the exception time to be logged.
+            self.io_loop.add_callback(self.io_loop.add_callback, self.stop)
+            1 / 0
+
+        self.io_loop.add_callback(callback)
+        with ExpectLog(app_log, "Exception in callback"):
+            self.wait()
+
+    def test_spawn_callback(self):
+        # Both add_callback and spawn_callback run directly on the IOLoop,
+        # so their errors are logged without stopping the test.
+        self.io_loop.add_callback(lambda: 1 / 0)
+        self.io_loop.add_callback(self.stop)
+        with ExpectLog(app_log, "Exception in callback"):
+            self.wait()
+        # A spawned callback is run directly on the IOLoop, so it will be
+        # logged without stopping the test.
+        self.io_loop.spawn_callback(lambda: 1 / 0)
+        self.io_loop.add_callback(self.stop)
+        with ExpectLog(app_log, "Exception in callback"):
+            self.wait()
+
+    @skipIfNonUnix
+    def test_remove_handler_from_handler(self):
+        # Create two sockets with simultaneous read events.
+        client, server = socket.socketpair()
+        try:
+            client.send(b"abc")
+            server.send(b"abc")
+
+            # After reading from one fd, remove the other from the IOLoop.
+            chunks = []
+
+            def handle_read(fd, events):
+                chunks.append(fd.recv(1024))
+                if fd is client:
+                    self.io_loop.remove_handler(server)
+                else:
+                    self.io_loop.remove_handler(client)
+
+            self.io_loop.add_handler(client, handle_read, self.io_loop.READ)
+            self.io_loop.add_handler(server, handle_read, self.io_loop.READ)
+            self.io_loop.call_later(0.1, self.stop)
+            self.wait()
+
+            # Only one fd was read; the other was cleanly removed.
+            self.assertEqual(chunks, [b"abc"])
+        finally:
+            client.close()
+            server.close()
+
+    @skipIfNonUnix
+    @gen_test
+    def test_init_close_race(self):
+        # Regression test for #2367
+        #
+        # Skipped on windows because of what looks like a bug in the
+        # proactor event loop when started and stopped on non-main
+        # threads.
+        def f():
+            for i in range(10):
+                loop = IOLoop(make_current=False)
+                loop.close()
+
+        yield gen.multi([self.io_loop.run_in_executor(None, f) for i in range(2)])
+
+    def test_explicit_asyncio_loop(self):
+        asyncio_loop = asyncio.new_event_loop()
+        loop = IOLoop(asyncio_loop=asyncio_loop, make_current=False)
+        assert loop.asyncio_loop is asyncio_loop  # type: ignore
+        with self.assertRaises(RuntimeError):
+            # Can't register two IOLoops with the same asyncio_loop
+            IOLoop(asyncio_loop=asyncio_loop, make_current=False)
+        loop.close()
+
+
+# Deliberately not a subclass of AsyncTestCase so the IOLoop isn't
+# automatically set as current.
+class TestIOLoopCurrent(unittest.TestCase):
+    def setUp(self):
+        setup_with_context_manager(self, ignore_deprecation())
+        self.io_loop = None  # type: typing.Optional[IOLoop]
+        IOLoop.clear_current()
+
+    def tearDown(self):
+        if self.io_loop is not None:
+            self.io_loop.close()
+
+    def test_non_current(self):
+        self.io_loop = IOLoop(make_current=False)
+        # The new IOLoop is not initially made current.
+        self.assertIsNone(IOLoop.current(instance=False))
+        # Starting the IOLoop makes it current, and stopping the loop
+        # makes it non-current. This process is repeatable.
+        for i in range(3):
+
+            def f():
+                self.current_io_loop = IOLoop.current()
+                assert self.io_loop is not None
+                self.io_loop.stop()
+
+            self.io_loop.add_callback(f)
+            self.io_loop.start()
+            self.assertIs(self.current_io_loop, self.io_loop)
+            # Now that the loop is stopped, it is no longer current.
+            self.assertIsNone(IOLoop.current(instance=False))
+
+    def test_force_current(self):
+        self.io_loop = IOLoop(make_current=True)
+        self.assertIs(self.io_loop, IOLoop.current())
+
+
+class TestIOLoopCurrentAsync(AsyncTestCase):
+    def setUp(self):
+        super().setUp()
+        setup_with_context_manager(self, ignore_deprecation())
+
+    @gen_test
+    def test_clear_without_current(self):
+        # If there is no current IOLoop, clear_current is a no-op (but
+        # should not fail). Use a thread so we see the threading.Local
+        # in a pristine state.
+        with ThreadPoolExecutor(1) as e:
+            yield e.submit(IOLoop.clear_current)
+
+
+class TestIOLoopFutures(AsyncTestCase):
+    def test_add_future_threads(self):
+        with futures.ThreadPoolExecutor(1) as pool:
+
+            def dummy():
+                pass
+
+            self.io_loop.add_future(
+                pool.submit(dummy), lambda future: self.stop(future)
+            )
+            future = self.wait()
+            self.assertTrue(future.done())
+            self.assertTrue(future.result() is None)
+
+    @gen_test
+    def test_run_in_executor_gen(self):
+        event1 = threading.Event()
+        event2 = threading.Event()
+
+        def sync_func(self_event, other_event):
+            self_event.set()
+            other_event.wait()
+            # Note that return value doesn't actually do anything,
+            # it is just passed through to our final assertion to
+            # make sure it is passed through properly.
+            return self_event
+
+        # Run two synchronous functions, which would deadlock if not
+        # run in parallel.
+        res = yield [
+            IOLoop.current().run_in_executor(None, sync_func, event1, event2),
+            IOLoop.current().run_in_executor(None, sync_func, event2, event1),
+        ]
+
+        self.assertEqual([event1, event2], res)
+
+    @gen_test
+    def test_run_in_executor_native(self):
+        event1 = threading.Event()
+        event2 = threading.Event()
+
+        def sync_func(self_event, other_event):
+            self_event.set()
+            other_event.wait()
+            return self_event
+
+        # Go through an async wrapper to ensure that the result of
+        # run_in_executor works with await and not just gen.coroutine
+        # (simply passing the underlying concurrent future would do that).
+        async def async_wrapper(self_event, other_event):
+            return await IOLoop.current().run_in_executor(
+                None, sync_func, self_event, other_event
+            )
+
+        res = yield [async_wrapper(event1, event2), async_wrapper(event2, event1)]
+
+        self.assertEqual([event1, event2], res)
+
+    @gen_test
+    def test_set_default_executor(self):
+        count = [0]
+
+        class MyExecutor(futures.ThreadPoolExecutor):
+            def submit(self, func, *args):
+                count[0] += 1
+                return super().submit(func, *args)
+
+        event = threading.Event()
+
+        def sync_func():
+            event.set()
+
+        executor = MyExecutor(1)
+        loop = IOLoop.current()
+        loop.set_default_executor(executor)
+        yield loop.run_in_executor(None, sync_func)
+        self.assertEqual(1, count[0])
+        self.assertTrue(event.is_set())
+
+
+class TestIOLoopRunSync(unittest.TestCase):
+    def setUp(self):
+        self.io_loop = IOLoop(make_current=False)
+
+    def tearDown(self):
+        self.io_loop.close()
+
+    def test_sync_result(self):
+        with self.assertRaises(gen.BadYieldError):
+            self.io_loop.run_sync(lambda: 42)
+
+    def test_sync_exception(self):
+        with self.assertRaises(ZeroDivisionError):
+            self.io_loop.run_sync(lambda: 1 / 0)
+
+    def test_async_result(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            raise gen.Return(42)
+
+        self.assertEqual(self.io_loop.run_sync(f), 42)
+
+    def test_async_exception(self):
+        @gen.coroutine
+        def f():
+            yield gen.moment
+            1 / 0
+
+        with self.assertRaises(ZeroDivisionError):
+            self.io_loop.run_sync(f)
+
+    def test_current(self):
+        def f():
+            self.assertIs(IOLoop.current(), self.io_loop)
+
+        self.io_loop.run_sync(f)
+
+    def test_timeout(self):
+        @gen.coroutine
+        def f():
+            yield gen.sleep(1)
+
+        self.assertRaises(TimeoutError, self.io_loop.run_sync, f, timeout=0.01)
+
+    def test_native_coroutine(self):
+        @gen.coroutine
+        def f1():
+            yield gen.moment
+
+        async def f2():
+            await f1()
+
+        self.io_loop.run_sync(f2)
+
+
+class TestPeriodicCallbackMath(unittest.TestCase):
+    def simulate_calls(self, pc, durations):
+        """Simulate a series of calls to the PeriodicCallback.
+
+        Pass a list of call durations in seconds (negative values
+        work to simulate clock adjustments during the call, or more or
+        less equivalently, between calls). This method returns the
+        times at which each call would be made.
+        """
+        calls = []
+        now = 1000
+        pc._next_timeout = now
+        for d in durations:
+            pc._update_next(now)
+            calls.append(pc._next_timeout)
+            now = pc._next_timeout + d
+        return calls
+
+    def dummy(self):
+        pass
+
+    def test_basic(self):
+        pc = PeriodicCallback(self.dummy, 10000)
+        self.assertEqual(
+            self.simulate_calls(pc, [0] * 5), [1010, 1020, 1030, 1040, 1050]
+        )
+
+    def test_overrun(self):
+        # If a call runs for too long, we skip entire cycles to get
+        # back on schedule.
+        call_durations = [9, 9, 10, 11, 20, 20, 35, 35, 0, 0, 0]
+        expected = [
+            1010,
+            1020,
+            1030,  # first 3 calls on schedule
+            1050,
+            1070,  # next 2 delayed one cycle
+            1100,
+            1130,  # next 2 delayed 2 cycles
+            1170,
+            1210,  # next 2 delayed 3 cycles
+            1220,
+            1230,  # then back on schedule.
+        ]
+
+        pc = PeriodicCallback(self.dummy, 10000)
+        self.assertEqual(self.simulate_calls(pc, call_durations), expected)
+
+    def test_clock_backwards(self):
+        pc = PeriodicCallback(self.dummy, 10000)
+        # Backwards jumps are ignored, potentially resulting in a
+        # slightly slow schedule (although we assume that when
+        # time.time() and time.monotonic() are different, time.time()
+        # is getting adjusted by NTP and is therefore more accurate)
+        self.assertEqual(
+            self.simulate_calls(pc, [-2, -1, -3, -2, 0]), [1010, 1020, 1030, 1040, 1050]
+        )
+
+        # For big jumps, we should perhaps alter the schedule, but we
+        # don't currently. This trace shows that we run callbacks
+        # every 10s of time.time(), but the first and second calls are
+        # 110s of real time apart because the backwards jump is
+        # ignored.
+        self.assertEqual(self.simulate_calls(pc, [-100, 0, 0]), [1010, 1020, 1030])
+
+    def test_jitter(self):
+        random_times = [0.5, 1, 0, 0.75]
+        expected = [1010, 1022.5, 1030, 1041.25]
+        call_durations = [0] * len(random_times)
+        pc = PeriodicCallback(self.dummy, 10000, jitter=0.5)
+
+        def mock_random():
+            return random_times.pop(0)
+
+        with mock.patch("random.random", mock_random):
+            self.assertEqual(self.simulate_calls(pc, call_durations), expected)
+
+    def test_timedelta(self):
+        pc = PeriodicCallback(lambda: None, datetime.timedelta(minutes=1, seconds=23))
+        expected_callback_time = 83000
+        self.assertEqual(pc.callback_time, expected_callback_time)
+
+
+class TestPeriodicCallbackAsync(AsyncTestCase):
+    def test_periodic_plain(self):
+        count = 0
+
+        def callback() -> None:
+            nonlocal count
+            count += 1
+            if count == 3:
+                self.stop()
+
+        pc = PeriodicCallback(callback, 10)
+        pc.start()
+        self.wait()
+        pc.stop()
+        self.assertEqual(count, 3)
+
+    def test_periodic_coro(self) -> None:
+        counts = [0, 0]
+
+        @gen.coroutine
+        def callback() -> "Generator[Future[None], object, None]":
+            counts[0] += 1
+            yield gen.sleep(0.025)
+            counts[1] += 1
+            if counts[1] == 3:
+                pc.stop()
+                self.io_loop.add_callback(self.stop)
+
+        pc = PeriodicCallback(callback, 10)
+        pc.start()
+        self.wait()
+        self.assertEqual(counts[0], 3)
+        self.assertEqual(counts[1], 3)
+
+    def test_periodic_async(self) -> None:
+        counts = [0, 0]
+
+        async def callback() -> None:
+            counts[0] += 1
+            await gen.sleep(0.025)
+            counts[1] += 1
+            if counts[1] == 3:
+                pc.stop()
+                self.io_loop.add_callback(self.stop)
+
+        pc = PeriodicCallback(callback, 10)
+        pc.start()
+        self.wait()
+        self.assertEqual(counts[0], 3)
+        self.assertEqual(counts[1], 3)
+
+
+class TestIOLoopConfiguration(unittest.TestCase):
+    def run_python(self, *statements):
+        stmt_list = [
+            "from tornado.ioloop import IOLoop",
+            "classname = lambda x: x.__class__.__name__",
+        ] + list(statements)
+        args = [sys.executable, "-c", "; ".join(stmt_list)]
+        return native_str(subprocess.check_output(args)).strip()
+
+    def test_default(self):
+        # When asyncio is available, it is used by default.
+        cls = self.run_python("print(classname(IOLoop.current()))")
+        self.assertEqual(cls, "AsyncIOMainLoop")
+        cls = self.run_python("print(classname(IOLoop()))")
+        self.assertEqual(cls, "AsyncIOLoop")
+
+    def test_asyncio(self):
+        cls = self.run_python(
+            'IOLoop.configure("tornado.platform.asyncio.AsyncIOLoop")',
+            "print(classname(IOLoop.current()))",
+        )
+        self.assertEqual(cls, "AsyncIOMainLoop")
+
+    def test_asyncio_main(self):
+        cls = self.run_python(
+            "from tornado.platform.asyncio import AsyncIOMainLoop",
+            "AsyncIOMainLoop().install()",
+            "print(classname(IOLoop.current()))",
+        )
+        self.assertEqual(cls, "AsyncIOMainLoop")
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/iostream_test.py b/venv/lib/python3.9/site-packages/tornado/test/iostream_test.py
new file mode 100644
index 00000000..e22e83e6
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/iostream_test.py
@@ -0,0 +1,1306 @@
+from tornado.concurrent import Future
+from tornado import gen
+from tornado import netutil
+from tornado.ioloop import IOLoop
+from tornado.iostream import (
+    IOStream,
+    SSLIOStream,
+    PipeIOStream,
+    StreamClosedError,
+    _StreamBuffer,
+)
+from tornado.httputil import HTTPHeaders
+from tornado.locks import Condition, Event
+from tornado.log import gen_log
+from tornado.netutil import ssl_options_to_context, ssl_wrap_socket
+from tornado.platform.asyncio import AddThreadSelectorEventLoop
+from tornado.tcpserver import TCPServer
+from tornado.testing import (
+    AsyncHTTPTestCase,
+    AsyncHTTPSTestCase,
+    AsyncTestCase,
+    bind_unused_port,
+    ExpectLog,
+    gen_test,
+)
+from tornado.test.util import (
+    skipIfNonUnix,
+    refusing_port,
+    skipPypy3V58,
+    ignore_deprecation,
+)
+from tornado.web import RequestHandler, Application
+import asyncio
+import errno
+import hashlib
+import logging
+import os
+import platform
+import random
+import socket
+import ssl
+import typing
+from unittest import mock
+import unittest
+
+
+def _server_ssl_options():
+    return dict(
+        certfile=os.path.join(os.path.dirname(__file__), "test.crt"),
+        keyfile=os.path.join(os.path.dirname(__file__), "test.key"),
+    )
+
+
+class HelloHandler(RequestHandler):
+    def get(self):
+        self.write("Hello")
+
+
+class TestIOStreamWebMixin(object):
+    def _make_client_iostream(self):
+        raise NotImplementedError()
+
+    def get_app(self):
+        return Application([("/", HelloHandler)])
+
+    def test_connection_closed(self: typing.Any):
+        # When a server sends a response and then closes the connection,
+        # the client must be allowed to read the data before the IOStream
+        # closes itself.  Epoll reports closed connections with a separate
+        # EPOLLRDHUP event delivered at the same time as the read event,
+        # while kqueue reports them as a second read/write event with an EOF
+        # flag.
+        response = self.fetch("/", headers={"Connection": "close"})
+        response.rethrow()
+
+    @gen_test
+    def test_read_until_close(self: typing.Any):
+        stream = self._make_client_iostream()
+        yield stream.connect(("127.0.0.1", self.get_http_port()))
+        stream.write(b"GET / HTTP/1.0\r\n\r\n")
+
+        data = yield stream.read_until_close()
+        self.assertTrue(data.startswith(b"HTTP/1.1 200"))
+        self.assertTrue(data.endswith(b"Hello"))
+
+    @gen_test
+    def test_read_zero_bytes(self: typing.Any):
+        self.stream = self._make_client_iostream()
+        yield self.stream.connect(("127.0.0.1", self.get_http_port()))
+        self.stream.write(b"GET / HTTP/1.0\r\n\r\n")
+
+        # normal read
+        data = yield self.stream.read_bytes(9)
+        self.assertEqual(data, b"HTTP/1.1 ")
+
+        # zero bytes
+        data = yield self.stream.read_bytes(0)
+        self.assertEqual(data, b"")
+
+        # another normal read
+        data = yield self.stream.read_bytes(3)
+        self.assertEqual(data, b"200")
+
+        self.stream.close()
+
+    @gen_test
+    def test_write_while_connecting(self: typing.Any):
+        stream = self._make_client_iostream()
+        connect_fut = stream.connect(("127.0.0.1", self.get_http_port()))
+        # unlike the previous tests, try to write before the connection
+        # is complete.
+        write_fut = stream.write(b"GET / HTTP/1.0\r\nConnection: close\r\n\r\n")
+        self.assertFalse(connect_fut.done())
+
+        # connect will always complete before write.
+        it = gen.WaitIterator(connect_fut, write_fut)
+        resolved_order = []
+        while not it.done():
+            yield it.next()
+            resolved_order.append(it.current_future)
+        self.assertEqual(resolved_order, [connect_fut, write_fut])
+
+        data = yield stream.read_until_close()
+        self.assertTrue(data.endswith(b"Hello"))
+
+        stream.close()
+
+    @gen_test
+    def test_future_interface(self: typing.Any):
+        """Basic test of IOStream's ability to return Futures."""
+        stream = self._make_client_iostream()
+        connect_result = yield stream.connect(("127.0.0.1", self.get_http_port()))
+        self.assertIs(connect_result, stream)
+        yield stream.write(b"GET / HTTP/1.0\r\n\r\n")
+        first_line = yield stream.read_until(b"\r\n")
+        self.assertEqual(first_line, b"HTTP/1.1 200 OK\r\n")
+        # callback=None is equivalent to no callback.
+        header_data = yield stream.read_until(b"\r\n\r\n")
+        headers = HTTPHeaders.parse(header_data.decode("latin1"))
+        content_length = int(headers["Content-Length"])
+        body = yield stream.read_bytes(content_length)
+        self.assertEqual(body, b"Hello")
+        stream.close()
+
+    @gen_test
+    def test_future_close_while_reading(self: typing.Any):
+        stream = self._make_client_iostream()
+        yield stream.connect(("127.0.0.1", self.get_http_port()))
+        yield stream.write(b"GET / HTTP/1.0\r\n\r\n")
+        with self.assertRaises(StreamClosedError):
+            yield stream.read_bytes(1024 * 1024)
+        stream.close()
+
+    @gen_test
+    def test_future_read_until_close(self: typing.Any):
+        # Ensure that the data comes through before the StreamClosedError.
+        stream = self._make_client_iostream()
+        yield stream.connect(("127.0.0.1", self.get_http_port()))
+        yield stream.write(b"GET / HTTP/1.0\r\nConnection: close\r\n\r\n")
+        yield stream.read_until(b"\r\n\r\n")
+        body = yield stream.read_until_close()
+        self.assertEqual(body, b"Hello")
+
+        # Nothing else to read; the error comes immediately without waiting
+        # for yield.
+        with self.assertRaises(StreamClosedError):
+            stream.read_bytes(1)
+
+
+class TestReadWriteMixin(object):
+    # Tests where one stream reads and the other writes.
+    # These should work for BaseIOStream implementations.
+
+    def make_iostream_pair(self, **kwargs):
+        raise NotImplementedError
+
+    def iostream_pair(self, **kwargs):
+        """Like make_iostream_pair, but called by ``async with``.
+
+        In py37 this becomes simpler with contextlib.asynccontextmanager.
+        """
+
+        class IOStreamPairContext:
+            def __init__(self, test, kwargs):
+                self.test = test
+                self.kwargs = kwargs
+
+            async def __aenter__(self):
+                self.pair = await self.test.make_iostream_pair(**self.kwargs)
+                return self.pair
+
+            async def __aexit__(self, typ, value, tb):
+                for s in self.pair:
+                    s.close()
+
+        return IOStreamPairContext(self, kwargs)
+
+    @gen_test
+    def test_write_zero_bytes(self):
+        # Attempting to write zero bytes should run the callback without
+        # going into an infinite loop.
+        rs, ws = yield self.make_iostream_pair()
+        yield ws.write(b"")
+        ws.close()
+        rs.close()
+
+    @gen_test
+    def test_future_delayed_close_callback(self: typing.Any):
+        # Same as test_delayed_close_callback, but with the future interface.
+        rs, ws = yield self.make_iostream_pair()
+
+        try:
+            ws.write(b"12")
+            chunks = []
+            chunks.append((yield rs.read_bytes(1)))
+            ws.close()
+            chunks.append((yield rs.read_bytes(1)))
+            self.assertEqual(chunks, [b"1", b"2"])
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_close_buffered_data(self: typing.Any):
+        # Similar to the previous test, but with data stored in the OS's
+        # socket buffers instead of the IOStream's read buffer.  Out-of-band
+        # close notifications must be delayed until all data has been
+        # drained into the IOStream buffer. (epoll used to use out-of-band
+        # close events with EPOLLRDHUP, but no longer)
+        #
+        # This depends on the read_chunk_size being smaller than the
+        # OS socket buffer, so make it small.
+        rs, ws = yield self.make_iostream_pair(read_chunk_size=256)
+        try:
+            ws.write(b"A" * 512)
+            data = yield rs.read_bytes(256)
+            self.assertEqual(b"A" * 256, data)
+            ws.close()
+            # Allow the close to propagate to the `rs` side of the
+            # connection.  Using add_callback instead of add_timeout
+            # doesn't seem to work, even with multiple iterations
+            yield gen.sleep(0.01)
+            data = yield rs.read_bytes(256)
+            self.assertEqual(b"A" * 256, data)
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_close_after_close(self: typing.Any):
+        # Similar to test_delayed_close_callback, but read_until_close takes
+        # a separate code path so test it separately.
+        rs, ws = yield self.make_iostream_pair()
+        try:
+            ws.write(b"1234")
+            # Read one byte to make sure the client has received the data.
+            # It won't run the close callback as long as there is more buffered
+            # data that could satisfy a later read.
+            data = yield rs.read_bytes(1)
+            ws.close()
+            self.assertEqual(data, b"1")
+            data = yield rs.read_until_close()
+            self.assertEqual(data, b"234")
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_large_read_until(self: typing.Any):
+        # Performance test: read_until used to have a quadratic component
+        # so a read_until of 4MB would take 8 seconds; now it takes 0.25
+        # seconds.
+        rs, ws = yield self.make_iostream_pair()
+        try:
+            # This test fails on pypy with ssl.  I think it's because
+            # pypy's gc defeats moves objects, breaking the
+            # "frozen write buffer" assumption.
+            if (
+                isinstance(rs, SSLIOStream)
+                and platform.python_implementation() == "PyPy"
+            ):
+                raise unittest.SkipTest("pypy gc causes problems with openssl")
+            NUM_KB = 4096
+            for i in range(NUM_KB):
+                ws.write(b"A" * 1024)
+            ws.write(b"\r\n")
+            data = yield rs.read_until(b"\r\n")
+            self.assertEqual(len(data), NUM_KB * 1024 + 2)
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    async def test_read_until_with_close_after_second_packet(self):
+        # This is a regression test for a regression in Tornado 6.0
+        # (maybe 6.0.3?) reported in
+        # https://github.com/tornadoweb/tornado/issues/2717
+        #
+        # The data arrives in two chunks; the stream is closed at the
+        # same time that the second chunk is received. If the second
+        # chunk is larger than the first, it works, but when this bug
+        # existed it would fail if the second chunk were smaller than
+        # the first. This is due to the optimization that the
+        # read_until condition is only checked when the buffer doubles
+        # in size
+        async with self.iostream_pair() as (rs, ws):
+            rf = asyncio.ensure_future(rs.read_until(b"done"))
+            # We need to wait for the read_until to actually start. On
+            # windows that's tricky because the selector runs in
+            # another thread; sleeping is the simplest way.
+            await asyncio.sleep(0.1)
+            await ws.write(b"x" * 2048)
+            ws.write(b"done")
+            ws.close()
+            await rf
+
+    @gen_test
+    async def test_read_until_unsatisfied_after_close(self: typing.Any):
+        # If a stream is closed while reading, it raises
+        # StreamClosedError instead of UnsatisfiableReadError (the
+        # latter should only be raised when byte limits are reached).
+        # The particular scenario tested here comes from #2717.
+        async with self.iostream_pair() as (rs, ws):
+            rf = asyncio.ensure_future(rs.read_until(b"done"))
+            await ws.write(b"x" * 2048)
+            ws.write(b"foo")
+            ws.close()
+            with self.assertRaises(StreamClosedError):
+                await rf
+
+    @gen_test
+    def test_close_callback_with_pending_read(self: typing.Any):
+        # Regression test for a bug that was introduced in 2.3
+        # where the IOStream._close_callback would never be called
+        # if there were pending reads.
+        OK = b"OK\r\n"
+        rs, ws = yield self.make_iostream_pair()
+        event = Event()
+        rs.set_close_callback(event.set)
+        try:
+            ws.write(OK)
+            res = yield rs.read_until(b"\r\n")
+            self.assertEqual(res, OK)
+
+            ws.close()
+            rs.read_until(b"\r\n")
+            # If _close_callback (self.stop) is not called,
+            # an AssertionError: Async operation timed out after 5 seconds
+            # will be raised.
+            yield event.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_future_close_callback(self: typing.Any):
+        # Regression test for interaction between the Future read interfaces
+        # and IOStream._maybe_add_error_listener.
+        rs, ws = yield self.make_iostream_pair()
+        closed = [False]
+        cond = Condition()
+
+        def close_callback():
+            closed[0] = True
+            cond.notify()
+
+        rs.set_close_callback(close_callback)
+        try:
+            ws.write(b"a")
+            res = yield rs.read_bytes(1)
+            self.assertEqual(res, b"a")
+            self.assertFalse(closed[0])
+            ws.close()
+            yield cond.wait()
+            self.assertTrue(closed[0])
+        finally:
+            rs.close()
+            ws.close()
+
+    @gen_test
+    def test_write_memoryview(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        try:
+            fut = rs.read_bytes(4)
+            ws.write(memoryview(b"hello"))
+            data = yield fut
+            self.assertEqual(data, b"hell")
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_bytes_partial(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        try:
+            # Ask for more than is available with partial=True
+            fut = rs.read_bytes(50, partial=True)
+            ws.write(b"hello")
+            data = yield fut
+            self.assertEqual(data, b"hello")
+
+            # Ask for less than what is available; num_bytes is still
+            # respected.
+            fut = rs.read_bytes(3, partial=True)
+            ws.write(b"world")
+            data = yield fut
+            self.assertEqual(data, b"wor")
+
+            # Partial reads won't return an empty string, but read_bytes(0)
+            # will.
+            data = yield rs.read_bytes(0, partial=True)
+            self.assertEqual(data, b"")
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_max_bytes(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Extra room under the limit
+            fut = rs.read_until(b"def", max_bytes=50)
+            ws.write(b"abcdef")
+            data = yield fut
+            self.assertEqual(data, b"abcdef")
+
+            # Just enough space
+            fut = rs.read_until(b"def", max_bytes=6)
+            ws.write(b"abcdef")
+            data = yield fut
+            self.assertEqual(data, b"abcdef")
+
+            # Not enough space, but we don't know it until all we can do is
+            # log a warning and close the connection.
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                fut = rs.read_until(b"def", max_bytes=5)
+                ws.write(b"123456")
+                yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_max_bytes_inline(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Similar to the error case in the previous test, but the
+            # ws writes first so rs reads are satisfied
+            # inline.  For consistency with the out-of-line case, we
+            # do not raise the error synchronously.
+            ws.write(b"123456")
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                with self.assertRaises(StreamClosedError):
+                    yield rs.read_until(b"def", max_bytes=5)
+            yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_max_bytes_ignores_extra(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Even though data that matches arrives the same packet that
+            # puts us over the limit, we fail the request because it was not
+            # found within the limit.
+            ws.write(b"abcdef")
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                rs.read_until(b"def", max_bytes=5)
+                yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_regex_max_bytes(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Extra room under the limit
+            fut = rs.read_until_regex(b"def", max_bytes=50)
+            ws.write(b"abcdef")
+            data = yield fut
+            self.assertEqual(data, b"abcdef")
+
+            # Just enough space
+            fut = rs.read_until_regex(b"def", max_bytes=6)
+            ws.write(b"abcdef")
+            data = yield fut
+            self.assertEqual(data, b"abcdef")
+
+            # Not enough space, but we don't know it until all we can do is
+            # log a warning and close the connection.
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                rs.read_until_regex(b"def", max_bytes=5)
+                ws.write(b"123456")
+                yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_regex_max_bytes_inline(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Similar to the error case in the previous test, but the
+            # ws writes first so rs reads are satisfied
+            # inline.  For consistency with the out-of-line case, we
+            # do not raise the error synchronously.
+            ws.write(b"123456")
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                rs.read_until_regex(b"def", max_bytes=5)
+                yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_until_regex_max_bytes_ignores_extra(self):
+        rs, ws = yield self.make_iostream_pair()
+        closed = Event()
+        rs.set_close_callback(closed.set)
+        try:
+            # Even though data that matches arrives the same packet that
+            # puts us over the limit, we fail the request because it was not
+            # found within the limit.
+            ws.write(b"abcdef")
+            with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+                rs.read_until_regex(b"def", max_bytes=5)
+                yield closed.wait()
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_small_reads_from_large_buffer(self: typing.Any):
+        # 10KB buffer size, 100KB available to read.
+        # Read 1KB at a time and make sure that the buffer is not eagerly
+        # filled.
+        rs, ws = yield self.make_iostream_pair(max_buffer_size=10 * 1024)
+        try:
+            ws.write(b"a" * 1024 * 100)
+            for i in range(100):
+                data = yield rs.read_bytes(1024)
+                self.assertEqual(data, b"a" * 1024)
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_small_read_untils_from_large_buffer(self: typing.Any):
+        # 10KB buffer size, 100KB available to read.
+        # Read 1KB at a time and make sure that the buffer is not eagerly
+        # filled.
+        rs, ws = yield self.make_iostream_pair(max_buffer_size=10 * 1024)
+        try:
+            ws.write((b"a" * 1023 + b"\n") * 100)
+            for i in range(100):
+                data = yield rs.read_until(b"\n", max_bytes=4096)
+                self.assertEqual(data, b"a" * 1023 + b"\n")
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_flow_control(self):
+        MB = 1024 * 1024
+        rs, ws = yield self.make_iostream_pair(max_buffer_size=5 * MB)
+        try:
+            # Client writes more than the rs will accept.
+            ws.write(b"a" * 10 * MB)
+            # The rs pauses while reading.
+            yield rs.read_bytes(MB)
+            yield gen.sleep(0.1)
+            # The ws's writes have been blocked; the rs can
+            # continue to read gradually.
+            for i in range(9):
+                yield rs.read_bytes(MB)
+        finally:
+            rs.close()
+            ws.close()
+
+    @gen_test
+    def test_read_into(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+
+        def sleep_some():
+            self.io_loop.run_sync(lambda: gen.sleep(0.05))
+
+        try:
+            buf = bytearray(10)
+            fut = rs.read_into(buf)
+            ws.write(b"hello")
+            yield gen.sleep(0.05)
+            self.assertTrue(rs.reading())
+            ws.write(b"world!!")
+            data = yield fut
+            self.assertFalse(rs.reading())
+            self.assertEqual(data, 10)
+            self.assertEqual(bytes(buf), b"helloworld")
+
+            # Existing buffer is fed into user buffer
+            fut = rs.read_into(buf)
+            yield gen.sleep(0.05)
+            self.assertTrue(rs.reading())
+            ws.write(b"1234567890")
+            data = yield fut
+            self.assertFalse(rs.reading())
+            self.assertEqual(data, 10)
+            self.assertEqual(bytes(buf), b"!!12345678")
+
+            # Existing buffer can satisfy read immediately
+            buf = bytearray(4)
+            ws.write(b"abcdefghi")
+            data = yield rs.read_into(buf)
+            self.assertEqual(data, 4)
+            self.assertEqual(bytes(buf), b"90ab")
+
+            data = yield rs.read_bytes(7)
+            self.assertEqual(data, b"cdefghi")
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_into_partial(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+
+        try:
+            # Partial read
+            buf = bytearray(10)
+            fut = rs.read_into(buf, partial=True)
+            ws.write(b"hello")
+            data = yield fut
+            self.assertFalse(rs.reading())
+            self.assertEqual(data, 5)
+            self.assertEqual(bytes(buf), b"hello\0\0\0\0\0")
+
+            # Full read despite partial=True
+            ws.write(b"world!1234567890")
+            data = yield rs.read_into(buf, partial=True)
+            self.assertEqual(data, 10)
+            self.assertEqual(bytes(buf), b"world!1234")
+
+            # Existing buffer can satisfy read immediately
+            data = yield rs.read_into(buf, partial=True)
+            self.assertEqual(data, 6)
+            self.assertEqual(bytes(buf), b"5678901234")
+
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_read_into_zero_bytes(self: typing.Any):
+        rs, ws = yield self.make_iostream_pair()
+        try:
+            buf = bytearray()
+            fut = rs.read_into(buf)
+            self.assertEqual(fut.result(), 0)
+        finally:
+            ws.close()
+            rs.close()
+
+    @gen_test
+    def test_many_mixed_reads(self):
+        # Stress buffer handling when going back and forth between
+        # read_bytes() (using an internal buffer) and read_into()
+        # (using a user-allocated buffer).
+        r = random.Random(42)
+        nbytes = 1000000
+        rs, ws = yield self.make_iostream_pair()
+
+        produce_hash = hashlib.sha1()
+        consume_hash = hashlib.sha1()
+
+        @gen.coroutine
+        def produce():
+            remaining = nbytes
+            while remaining > 0:
+                size = r.randint(1, min(1000, remaining))
+                data = os.urandom(size)
+                produce_hash.update(data)
+                yield ws.write(data)
+                remaining -= size
+            assert remaining == 0
+
+        @gen.coroutine
+        def consume():
+            remaining = nbytes
+            while remaining > 0:
+                if r.random() > 0.5:
+                    # read_bytes()
+                    size = r.randint(1, min(1000, remaining))
+                    data = yield rs.read_bytes(size)
+                    consume_hash.update(data)
+                    remaining -= size
+                else:
+                    # read_into()
+                    size = r.randint(1, min(1000, remaining))
+                    buf = bytearray(size)
+                    n = yield rs.read_into(buf)
+                    assert n == size
+                    consume_hash.update(buf)
+                    remaining -= size
+            assert remaining == 0
+
+        try:
+            yield [produce(), consume()]
+            assert produce_hash.hexdigest() == consume_hash.hexdigest()
+        finally:
+            ws.close()
+            rs.close()
+
+
+class TestIOStreamMixin(TestReadWriteMixin):
+    def _make_server_iostream(self, connection, **kwargs):
+        raise NotImplementedError()
+
+    def _make_client_iostream(self, connection, **kwargs):
+        raise NotImplementedError()
+
+    @gen.coroutine
+    def make_iostream_pair(self: typing.Any, **kwargs):
+        listener, port = bind_unused_port()
+        server_stream_fut = Future()  # type: Future[IOStream]
+
+        def accept_callback(connection, address):
+            server_stream_fut.set_result(
+                self._make_server_iostream(connection, **kwargs)
+            )
+
+        netutil.add_accept_handler(listener, accept_callback)
+        client_stream = self._make_client_iostream(socket.socket(), **kwargs)
+        connect_fut = client_stream.connect(("127.0.0.1", port))
+        server_stream, client_stream = yield [server_stream_fut, connect_fut]
+        self.io_loop.remove_handler(listener.fileno())
+        listener.close()
+        raise gen.Return((server_stream, client_stream))
+
+    @gen_test
+    def test_connection_refused(self: typing.Any):
+        # When a connection is refused, the connect callback should not
+        # be run.  (The kqueue IOLoop used to behave differently from the
+        # epoll IOLoop in this respect)
+        cleanup_func, port = refusing_port()
+        self.addCleanup(cleanup_func)
+        stream = IOStream(socket.socket())
+
+        stream.set_close_callback(self.stop)
+        # log messages vary by platform and ioloop implementation
+        with ExpectLog(gen_log, ".*", required=False):
+            with self.assertRaises(StreamClosedError):
+                yield stream.connect(("127.0.0.1", port))
+
+        self.assertTrue(isinstance(stream.error, ConnectionRefusedError), stream.error)
+
+    @gen_test
+    def test_gaierror(self: typing.Any):
+        # Test that IOStream sets its exc_info on getaddrinfo error.
+        # It's difficult to reliably trigger a getaddrinfo error;
+        # some resolvers own't even return errors for malformed names,
+        # so we mock it instead. If IOStream changes to call a Resolver
+        # before sock.connect, the mock target will need to change too.
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
+        stream = IOStream(s)
+        stream.set_close_callback(self.stop)
+        with mock.patch(
+            "socket.socket.connect", side_effect=socket.gaierror(errno.EIO, "boom")
+        ):
+            with self.assertRaises(StreamClosedError):
+                yield stream.connect(("localhost", 80))
+            self.assertTrue(isinstance(stream.error, socket.gaierror))
+
+    @gen_test
+    def test_read_until_close_with_error(self: typing.Any):
+        server, client = yield self.make_iostream_pair()
+        try:
+            with mock.patch(
+                "tornado.iostream.BaseIOStream._try_inline_read",
+                side_effect=IOError("boom"),
+            ):
+                with self.assertRaisesRegex(IOError, "boom"):
+                    client.read_until_close()
+        finally:
+            server.close()
+            client.close()
+
+    @skipIfNonUnix
+    @skipPypy3V58
+    @gen_test
+    def test_inline_read_error(self: typing.Any):
+        # An error on an inline read is raised without logging (on the
+        # assumption that it will eventually be noticed or logged further
+        # up the stack).
+        #
+        # This test is posix-only because windows os.close() doesn't work
+        # on socket FDs, but we can't close the socket object normally
+        # because we won't get the error we want if the socket knows
+        # it's closed.
+        #
+        # This test is also disabled when the
+        # AddThreadSelectorEventLoop is used, because a race between
+        # this thread closing the socket and the selector thread
+        # calling the select system call can make this test flaky.
+        # This event loop implementation is normally only used on
+        # windows, making this check redundant with skipIfNonUnix, but
+        # we sometimes enable it on other platforms for testing.
+        io_loop = IOLoop.current()
+        if isinstance(
+            io_loop.selector_loop,  # type: ignore[attr-defined]
+            AddThreadSelectorEventLoop,
+        ):
+            self.skipTest("AddThreadSelectorEventLoop not supported")
+        server, client = yield self.make_iostream_pair()
+        try:
+            os.close(server.socket.fileno())
+            with self.assertRaises(socket.error):
+                server.read_bytes(1)
+        finally:
+            server.close()
+            client.close()
+
+    @skipPypy3V58
+    @gen_test
+    def test_async_read_error_logging(self):
+        # Socket errors on asynchronous reads should be logged (but only
+        # once).
+        server, client = yield self.make_iostream_pair()
+        closed = Event()
+        server.set_close_callback(closed.set)
+        try:
+            # Start a read that will be fulfilled asynchronously.
+            server.read_bytes(1)
+            client.write(b"a")
+            # Stub out read_from_fd to make it fail.
+
+            def fake_read_from_fd():
+                os.close(server.socket.fileno())
+                server.__class__.read_from_fd(server)
+
+            server.read_from_fd = fake_read_from_fd
+            # This log message is from _handle_read (not read_from_fd).
+            with ExpectLog(gen_log, "error on read"):
+                yield closed.wait()
+        finally:
+            server.close()
+            client.close()
+
+    @gen_test
+    def test_future_write(self):
+        """
+        Test that write() Futures are never orphaned.
+        """
+        # Run concurrent writers that will write enough bytes so as to
+        # clog the socket buffer and accumulate bytes in our write buffer.
+        m, n = 5000, 1000
+        nproducers = 10
+        total_bytes = m * n * nproducers
+        server, client = yield self.make_iostream_pair(max_buffer_size=total_bytes)
+
+        @gen.coroutine
+        def produce():
+            data = b"x" * m
+            for i in range(n):
+                yield server.write(data)
+
+        @gen.coroutine
+        def consume():
+            nread = 0
+            while nread < total_bytes:
+                res = yield client.read_bytes(m)
+                nread += len(res)
+
+        try:
+            yield [produce() for i in range(nproducers)] + [consume()]
+        finally:
+            server.close()
+            client.close()
+
+
+class TestIOStreamWebHTTP(TestIOStreamWebMixin, AsyncHTTPTestCase):
+    def _make_client_iostream(self):
+        return IOStream(socket.socket())
+
+
+class TestIOStreamWebHTTPS(TestIOStreamWebMixin, AsyncHTTPSTestCase):
+    def _make_client_iostream(self):
+        return SSLIOStream(socket.socket(), ssl_options=dict(cert_reqs=ssl.CERT_NONE))
+
+
+class TestIOStream(TestIOStreamMixin, AsyncTestCase):
+    def _make_server_iostream(self, connection, **kwargs):
+        return IOStream(connection, **kwargs)
+
+    def _make_client_iostream(self, connection, **kwargs):
+        return IOStream(connection, **kwargs)
+
+
+class TestIOStreamSSL(TestIOStreamMixin, AsyncTestCase):
+    def _make_server_iostream(self, connection, **kwargs):
+        ssl_ctx = ssl_options_to_context(_server_ssl_options(), server_side=True)
+        connection = ssl_ctx.wrap_socket(
+            connection,
+            server_side=True,
+            do_handshake_on_connect=False,
+        )
+        return SSLIOStream(connection, **kwargs)
+
+    def _make_client_iostream(self, connection, **kwargs):
+        return SSLIOStream(
+            connection, ssl_options=dict(cert_reqs=ssl.CERT_NONE), **kwargs
+        )
+
+
+# This will run some tests that are basically redundant but it's the
+# simplest way to make sure that it works to pass an SSLContext
+# instead of an ssl_options dict to the SSLIOStream constructor.
+class TestIOStreamSSLContext(TestIOStreamMixin, AsyncTestCase):
+    def _make_server_iostream(self, connection, **kwargs):
+        context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+        context.load_cert_chain(
+            os.path.join(os.path.dirname(__file__), "test.crt"),
+            os.path.join(os.path.dirname(__file__), "test.key"),
+        )
+        connection = ssl_wrap_socket(
+            connection, context, server_side=True, do_handshake_on_connect=False
+        )
+        return SSLIOStream(connection, **kwargs)
+
+    def _make_client_iostream(self, connection, **kwargs):
+        context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
+        context.check_hostname = False
+        context.verify_mode = ssl.CERT_NONE
+        return SSLIOStream(connection, ssl_options=context, **kwargs)
+
+
+class TestIOStreamStartTLS(AsyncTestCase):
+    def setUp(self):
+        try:
+            super().setUp()
+            self.listener, self.port = bind_unused_port()
+            self.server_stream = None
+            self.server_accepted = Future()  # type: Future[None]
+            netutil.add_accept_handler(self.listener, self.accept)
+            self.client_stream = IOStream(
+                socket.socket()
+            )  # type: typing.Optional[IOStream]
+            self.io_loop.add_future(
+                self.client_stream.connect(("127.0.0.1", self.port)), self.stop
+            )
+            self.wait()
+            self.io_loop.add_future(self.server_accepted, self.stop)
+            self.wait()
+        except Exception as e:
+            print(e)
+            raise
+
+    def tearDown(self):
+        if self.server_stream is not None:
+            self.server_stream.close()
+        if self.client_stream is not None:
+            self.client_stream.close()
+        self.io_loop.remove_handler(self.listener.fileno())
+        self.listener.close()
+        super().tearDown()
+
+    def accept(self, connection, address):
+        if self.server_stream is not None:
+            self.fail("should only get one connection")
+        self.server_stream = IOStream(connection)
+        self.server_accepted.set_result(None)
+
+    @gen.coroutine
+    def client_send_line(self, line):
+        assert self.client_stream is not None
+        self.client_stream.write(line)
+        assert self.server_stream is not None
+        recv_line = yield self.server_stream.read_until(b"\r\n")
+        self.assertEqual(line, recv_line)
+
+    @gen.coroutine
+    def server_send_line(self, line):
+        assert self.server_stream is not None
+        self.server_stream.write(line)
+        assert self.client_stream is not None
+        recv_line = yield self.client_stream.read_until(b"\r\n")
+        self.assertEqual(line, recv_line)
+
+    def client_start_tls(self, ssl_options=None, server_hostname=None):
+        assert self.client_stream is not None
+        client_stream = self.client_stream
+        self.client_stream = None
+        return client_stream.start_tls(False, ssl_options, server_hostname)
+
+    def server_start_tls(self, ssl_options=None):
+        assert self.server_stream is not None
+        server_stream = self.server_stream
+        self.server_stream = None
+        return server_stream.start_tls(True, ssl_options)
+
+    @gen_test
+    def test_start_tls_smtp(self):
+        # This flow is simplified from RFC 3207 section 5.
+        # We don't really need all of this, but it helps to make sure
+        # that after realistic back-and-forth traffic the buffers end up
+        # in a sane state.
+        yield self.server_send_line(b"220 mail.example.com ready\r\n")
+        yield self.client_send_line(b"EHLO mail.example.com\r\n")
+        yield self.server_send_line(b"250-mail.example.com welcome\r\n")
+        yield self.server_send_line(b"250 STARTTLS\r\n")
+        yield self.client_send_line(b"STARTTLS\r\n")
+        yield self.server_send_line(b"220 Go ahead\r\n")
+        client_future = self.client_start_tls(dict(cert_reqs=ssl.CERT_NONE))
+        server_future = self.server_start_tls(_server_ssl_options())
+        self.client_stream = yield client_future
+        self.server_stream = yield server_future
+        self.assertTrue(isinstance(self.client_stream, SSLIOStream))
+        self.assertTrue(isinstance(self.server_stream, SSLIOStream))
+        yield self.client_send_line(b"EHLO mail.example.com\r\n")
+        yield self.server_send_line(b"250 mail.example.com welcome\r\n")
+
+    @gen_test
+    def test_handshake_fail(self):
+        server_future = self.server_start_tls(_server_ssl_options())
+        # Certificates are verified with the default configuration.
+        with ExpectLog(gen_log, "SSL Error"):
+            client_future = self.client_start_tls(server_hostname="localhost")
+            with self.assertRaises(ssl.SSLError):
+                yield client_future
+            with self.assertRaises((ssl.SSLError, socket.error)):
+                yield server_future
+
+    @gen_test
+    def test_check_hostname(self):
+        # Test that server_hostname parameter to start_tls is being used.
+        # The check_hostname functionality is only available in python 2.7 and
+        # up and in python 3.4 and up.
+        server_future = self.server_start_tls(_server_ssl_options())
+        with ExpectLog(gen_log, "SSL Error"):
+            client_future = self.client_start_tls(
+                ssl.create_default_context(), server_hostname="127.0.0.1"
+            )
+            with self.assertRaises(ssl.SSLError):
+                # The client fails to connect with an SSL error.
+                yield client_future
+            with self.assertRaises(Exception):
+                # The server fails to connect, but the exact error is unspecified.
+                yield server_future
+
+    @gen_test
+    def test_typed_memoryview(self):
+        # Test support of memoryviews with an item size greater than 1 byte.
+        buf = memoryview(bytes(80)).cast("L")
+        assert self.server_stream is not None
+        yield self.server_stream.write(buf)
+        assert self.client_stream is not None
+        # This will timeout if the calculation of the buffer size is incorrect
+        recv = yield self.client_stream.read_bytes(buf.nbytes)
+        self.assertEqual(bytes(recv), bytes(buf))
+
+
+class WaitForHandshakeTest(AsyncTestCase):
+    @gen.coroutine
+    def connect_to_server(self, server_cls):
+        server = client = None
+        try:
+            sock, port = bind_unused_port()
+            server = server_cls(ssl_options=_server_ssl_options())
+            server.add_socket(sock)
+
+            ssl_ctx = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
+            ssl_ctx.check_hostname = False
+            ssl_ctx.verify_mode = ssl.CERT_NONE
+            # These tests fail with ConnectionAbortedErrors with TLS
+            # 1.3 on windows python 3.7.4 (which includes an upgrade
+            # to openssl 1.1.c. Other platforms might be affected with
+            # newer openssl too). Disable it until we figure out
+            # what's up.
+            # Update 2021-12-28: Still happening with Python 3.10 on
+            # Windows. OP_NO_TLSv1_3 now raises a DeprecationWarning.
+            with ignore_deprecation():
+                ssl_ctx.options |= getattr(ssl, "OP_NO_TLSv1_3", 0)
+                client = SSLIOStream(socket.socket(), ssl_options=ssl_ctx)
+            yield client.connect(("127.0.0.1", port))
+            self.assertIsNotNone(client.socket.cipher())
+        finally:
+            if server is not None:
+                server.stop()
+            if client is not None:
+                client.close()
+
+    @gen_test
+    def test_wait_for_handshake_future(self):
+        test = self
+        handshake_future = Future()  # type: Future[None]
+
+        class TestServer(TCPServer):
+            def handle_stream(self, stream, address):
+                test.assertIsNone(stream.socket.cipher())
+                test.io_loop.spawn_callback(self.handle_connection, stream)
+
+            @gen.coroutine
+            def handle_connection(self, stream):
+                yield stream.wait_for_handshake()
+                handshake_future.set_result(None)
+
+        yield self.connect_to_server(TestServer)
+        yield handshake_future
+
+    @gen_test
+    def test_wait_for_handshake_already_waiting_error(self):
+        test = self
+        handshake_future = Future()  # type: Future[None]
+
+        class TestServer(TCPServer):
+            @gen.coroutine
+            def handle_stream(self, stream, address):
+                fut = stream.wait_for_handshake()
+                test.assertRaises(RuntimeError, stream.wait_for_handshake)
+                yield fut
+
+                handshake_future.set_result(None)
+
+        yield self.connect_to_server(TestServer)
+        yield handshake_future
+
+    @gen_test
+    def test_wait_for_handshake_already_connected(self):
+        handshake_future = Future()  # type: Future[None]
+
+        class TestServer(TCPServer):
+            @gen.coroutine
+            def handle_stream(self, stream, address):
+                yield stream.wait_for_handshake()
+                yield stream.wait_for_handshake()
+                handshake_future.set_result(None)
+
+        yield self.connect_to_server(TestServer)
+        yield handshake_future
+
+
+@skipIfNonUnix
+class TestPipeIOStream(TestReadWriteMixin, AsyncTestCase):
+    @gen.coroutine
+    def make_iostream_pair(self, **kwargs):
+        r, w = os.pipe()
+
+        return PipeIOStream(r, **kwargs), PipeIOStream(w, **kwargs)
+
+    @gen_test
+    def test_pipe_iostream(self):
+        rs, ws = yield self.make_iostream_pair()
+
+        ws.write(b"hel")
+        ws.write(b"lo world")
+
+        data = yield rs.read_until(b" ")
+        self.assertEqual(data, b"hello ")
+
+        data = yield rs.read_bytes(3)
+        self.assertEqual(data, b"wor")
+
+        ws.close()
+
+        data = yield rs.read_until_close()
+        self.assertEqual(data, b"ld")
+
+        rs.close()
+
+    @gen_test
+    def test_pipe_iostream_big_write(self):
+        rs, ws = yield self.make_iostream_pair()
+
+        NUM_BYTES = 1048576
+
+        # Write 1MB of data, which should fill the buffer
+        ws.write(b"1" * NUM_BYTES)
+
+        data = yield rs.read_bytes(NUM_BYTES)
+        self.assertEqual(data, b"1" * NUM_BYTES)
+
+        ws.close()
+        rs.close()
+
+
+class TestStreamBuffer(unittest.TestCase):
+    """
+    Unit tests for the private _StreamBuffer class.
+    """
+
+    def setUp(self):
+        self.random = random.Random(42)
+
+    def to_bytes(self, b):
+        if isinstance(b, (bytes, bytearray)):
+            return bytes(b)
+        elif isinstance(b, memoryview):
+            return b.tobytes()  # For py2
+        else:
+            raise TypeError(b)
+
+    def make_streambuffer(self, large_buf_threshold=10):
+        buf = _StreamBuffer()
+        assert buf._large_buf_threshold
+        buf._large_buf_threshold = large_buf_threshold
+        return buf
+
+    def check_peek(self, buf, expected):
+        size = 1
+        while size < 2 * len(expected):
+            got = self.to_bytes(buf.peek(size))
+            self.assertTrue(got)  # Not empty
+            self.assertLessEqual(len(got), size)
+            self.assertTrue(expected.startswith(got), (expected, got))
+            size = (size * 3 + 1) // 2
+
+    def check_append_all_then_skip_all(self, buf, objs, input_type):
+        self.assertEqual(len(buf), 0)
+
+        expected = b""
+
+        for o in objs:
+            expected += o
+            buf.append(input_type(o))
+            self.assertEqual(len(buf), len(expected))
+            self.check_peek(buf, expected)
+
+        while expected:
+            n = self.random.randrange(1, len(expected) + 1)
+            expected = expected[n:]
+            buf.advance(n)
+            self.assertEqual(len(buf), len(expected))
+            self.check_peek(buf, expected)
+
+        self.assertEqual(len(buf), 0)
+
+    def test_small(self):
+        objs = [b"12", b"345", b"67", b"89a", b"bcde", b"fgh", b"ijklmn"]
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, bytes)
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, bytearray)
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, memoryview)
+
+        # Test internal algorithm
+        buf = self.make_streambuffer(10)
+        for i in range(9):
+            buf.append(b"x")
+        self.assertEqual(len(buf._buffers), 1)
+        for i in range(9):
+            buf.append(b"x")
+        self.assertEqual(len(buf._buffers), 2)
+        buf.advance(10)
+        self.assertEqual(len(buf._buffers), 1)
+        buf.advance(8)
+        self.assertEqual(len(buf._buffers), 0)
+        self.assertEqual(len(buf), 0)
+
+    def test_large(self):
+        objs = [
+            b"12" * 5,
+            b"345" * 2,
+            b"67" * 20,
+            b"89a" * 12,
+            b"bcde" * 1,
+            b"fgh" * 7,
+            b"ijklmn" * 2,
+        ]
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, bytes)
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, bytearray)
+
+        buf = self.make_streambuffer()
+        self.check_append_all_then_skip_all(buf, objs, memoryview)
+
+        # Test internal algorithm
+        buf = self.make_streambuffer(10)
+        for i in range(3):
+            buf.append(b"x" * 11)
+        self.assertEqual(len(buf._buffers), 3)
+        buf.append(b"y")
+        self.assertEqual(len(buf._buffers), 4)
+        buf.append(b"z")
+        self.assertEqual(len(buf._buffers), 4)
+        buf.advance(33)
+        self.assertEqual(len(buf._buffers), 1)
+        buf.advance(2)
+        self.assertEqual(len(buf._buffers), 0)
+        self.assertEqual(len(buf), 0)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/locale_test.py b/venv/lib/python3.9/site-packages/tornado/test/locale_test.py
new file mode 100644
index 00000000..ee74cb05
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/locale_test.py
@@ -0,0 +1,149 @@
+import datetime
+import os
+import shutil
+import tempfile
+import unittest
+
+import tornado.locale
+from tornado.escape import utf8, to_unicode
+from tornado.util import unicode_type
+
+
+class TranslationLoaderTest(unittest.TestCase):
+    # TODO: less hacky way to get isolated tests
+    SAVE_VARS = ["_translations", "_supported_locales", "_use_gettext"]
+
+    def clear_locale_cache(self):
+        tornado.locale.Locale._cache = {}
+
+    def setUp(self):
+        self.saved = {}  # type: dict
+        for var in TranslationLoaderTest.SAVE_VARS:
+            self.saved[var] = getattr(tornado.locale, var)
+        self.clear_locale_cache()
+
+    def tearDown(self):
+        for k, v in self.saved.items():
+            setattr(tornado.locale, k, v)
+        self.clear_locale_cache()
+
+    def test_csv(self):
+        tornado.locale.load_translations(
+            os.path.join(os.path.dirname(__file__), "csv_translations")
+        )
+        locale = tornado.locale.get("fr_FR")
+        self.assertTrue(isinstance(locale, tornado.locale.CSVLocale))
+        self.assertEqual(locale.translate("school"), "\u00e9cole")
+
+    def test_csv_bom(self):
+        with open(
+            os.path.join(os.path.dirname(__file__), "csv_translations", "fr_FR.csv"),
+            "rb",
+        ) as f:
+            char_data = to_unicode(f.read())
+        # Re-encode our input data (which is utf-8 without BOM) in
+        # encodings that use the BOM and ensure that we can still load
+        # it. Note that utf-16-le and utf-16-be do not write a BOM,
+        # so we only test whichver variant is native to our platform.
+        for encoding in ["utf-8-sig", "utf-16"]:
+            tmpdir = tempfile.mkdtemp()
+            try:
+                with open(os.path.join(tmpdir, "fr_FR.csv"), "wb") as f:
+                    f.write(char_data.encode(encoding))
+                tornado.locale.load_translations(tmpdir)
+                locale = tornado.locale.get("fr_FR")
+                self.assertIsInstance(locale, tornado.locale.CSVLocale)
+                self.assertEqual(locale.translate("school"), "\u00e9cole")
+            finally:
+                shutil.rmtree(tmpdir)
+
+    def test_gettext(self):
+        tornado.locale.load_gettext_translations(
+            os.path.join(os.path.dirname(__file__), "gettext_translations"),
+            "tornado_test",
+        )
+        locale = tornado.locale.get("fr_FR")
+        self.assertTrue(isinstance(locale, tornado.locale.GettextLocale))
+        self.assertEqual(locale.translate("school"), "\u00e9cole")
+        self.assertEqual(locale.pgettext("law", "right"), "le droit")
+        self.assertEqual(locale.pgettext("good", "right"), "le bien")
+        self.assertEqual(locale.pgettext("organization", "club", "clubs", 1), "le club")
+        self.assertEqual(
+            locale.pgettext("organization", "club", "clubs", 2), "les clubs"
+        )
+        self.assertEqual(locale.pgettext("stick", "club", "clubs", 1), "le b\xe2ton")
+        self.assertEqual(locale.pgettext("stick", "club", "clubs", 2), "les b\xe2tons")
+
+
+class LocaleDataTest(unittest.TestCase):
+    def test_non_ascii_name(self):
+        name = tornado.locale.LOCALE_NAMES["es_LA"]["name"]
+        self.assertTrue(isinstance(name, unicode_type))
+        self.assertEqual(name, "Espa\u00f1ol")
+        self.assertEqual(utf8(name), b"Espa\xc3\xb1ol")
+
+
+class EnglishTest(unittest.TestCase):
+    def test_format_date(self):
+        locale = tornado.locale.get("en_US")
+        date = datetime.datetime(2013, 4, 28, 18, 35)
+        self.assertEqual(
+            locale.format_date(date, full_format=True), "April 28, 2013 at 6:35 pm"
+        )
+
+        now = datetime.datetime.utcnow()
+
+        self.assertEqual(
+            locale.format_date(now - datetime.timedelta(seconds=2), full_format=False),
+            "2 seconds ago",
+        )
+        self.assertEqual(
+            locale.format_date(now - datetime.timedelta(minutes=2), full_format=False),
+            "2 minutes ago",
+        )
+        self.assertEqual(
+            locale.format_date(now - datetime.timedelta(hours=2), full_format=False),
+            "2 hours ago",
+        )
+
+        self.assertEqual(
+            locale.format_date(
+                now - datetime.timedelta(days=1), full_format=False, shorter=True
+            ),
+            "yesterday",
+        )
+
+        date = now - datetime.timedelta(days=2)
+        self.assertEqual(
+            locale.format_date(date, full_format=False, shorter=True),
+            locale._weekdays[date.weekday()],
+        )
+
+        date = now - datetime.timedelta(days=300)
+        self.assertEqual(
+            locale.format_date(date, full_format=False, shorter=True),
+            "%s %d" % (locale._months[date.month - 1], date.day),
+        )
+
+        date = now - datetime.timedelta(days=500)
+        self.assertEqual(
+            locale.format_date(date, full_format=False, shorter=True),
+            "%s %d, %d" % (locale._months[date.month - 1], date.day, date.year),
+        )
+
+    def test_friendly_number(self):
+        locale = tornado.locale.get("en_US")
+        self.assertEqual(locale.friendly_number(1000000), "1,000,000")
+
+    def test_list(self):
+        locale = tornado.locale.get("en_US")
+        self.assertEqual(locale.list([]), "")
+        self.assertEqual(locale.list(["A"]), "A")
+        self.assertEqual(locale.list(["A", "B"]), "A and B")
+        self.assertEqual(locale.list(["A", "B", "C"]), "A, B and C")
+
+    def test_format_day(self):
+        locale = tornado.locale.get("en_US")
+        date = datetime.datetime(2013, 4, 28, 18, 35)
+        self.assertEqual(locale.format_day(date=date, dow=True), "Sunday, April 28")
+        self.assertEqual(locale.format_day(date=date, dow=False), "April 28")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/locks_test.py b/venv/lib/python3.9/site-packages/tornado/test/locks_test.py
new file mode 100644
index 00000000..23e1c520
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/locks_test.py
@@ -0,0 +1,535 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import asyncio
+from datetime import timedelta
+import typing  # noqa: F401
+import unittest
+
+from tornado import gen, locks
+from tornado.gen import TimeoutError
+from tornado.testing import gen_test, AsyncTestCase
+
+
+class ConditionTest(AsyncTestCase):
+    def setUp(self):
+        super().setUp()
+        self.history = []  # type: typing.List[typing.Union[int, str]]
+
+    def record_done(self, future, key):
+        """Record the resolution of a Future returned by Condition.wait."""
+
+        def callback(_):
+            if not future.result():
+                # wait() resolved to False, meaning it timed out.
+                self.history.append("timeout")
+            else:
+                self.history.append(key)
+
+        future.add_done_callback(callback)
+
+    def loop_briefly(self):
+        """Run all queued callbacks on the IOLoop.
+
+        In these tests, this method is used after calling notify() to
+        preserve the pre-5.0 behavior in which callbacks ran
+        synchronously.
+        """
+        self.io_loop.add_callback(self.stop)
+        self.wait()
+
+    def test_repr(self):
+        c = locks.Condition()
+        self.assertIn("Condition", repr(c))
+        self.assertNotIn("waiters", repr(c))
+        c.wait()
+        self.assertIn("waiters", repr(c))
+
+    @gen_test
+    def test_notify(self):
+        c = locks.Condition()
+        self.io_loop.call_later(0.01, c.notify)
+        yield c.wait()
+
+    def test_notify_1(self):
+        c = locks.Condition()
+        self.record_done(c.wait(), "wait1")
+        self.record_done(c.wait(), "wait2")
+        c.notify(1)
+        self.loop_briefly()
+        self.history.append("notify1")
+        c.notify(1)
+        self.loop_briefly()
+        self.history.append("notify2")
+        self.assertEqual(["wait1", "notify1", "wait2", "notify2"], self.history)
+
+    def test_notify_n(self):
+        c = locks.Condition()
+        for i in range(6):
+            self.record_done(c.wait(), i)
+
+        c.notify(3)
+        self.loop_briefly()
+
+        # Callbacks execute in the order they were registered.
+        self.assertEqual(list(range(3)), self.history)
+        c.notify(1)
+        self.loop_briefly()
+        self.assertEqual(list(range(4)), self.history)
+        c.notify(2)
+        self.loop_briefly()
+        self.assertEqual(list(range(6)), self.history)
+
+    def test_notify_all(self):
+        c = locks.Condition()
+        for i in range(4):
+            self.record_done(c.wait(), i)
+
+        c.notify_all()
+        self.loop_briefly()
+        self.history.append("notify_all")
+
+        # Callbacks execute in the order they were registered.
+        self.assertEqual(list(range(4)) + ["notify_all"], self.history)  # type: ignore
+
+    @gen_test
+    def test_wait_timeout(self):
+        c = locks.Condition()
+        wait = c.wait(timedelta(seconds=0.01))
+        self.io_loop.call_later(0.02, c.notify)  # Too late.
+        yield gen.sleep(0.03)
+        self.assertFalse((yield wait))
+
+    @gen_test
+    def test_wait_timeout_preempted(self):
+        c = locks.Condition()
+
+        # This fires before the wait times out.
+        self.io_loop.call_later(0.01, c.notify)
+        wait = c.wait(timedelta(seconds=0.02))
+        yield gen.sleep(0.03)
+        yield wait  # No TimeoutError.
+
+    @gen_test
+    def test_notify_n_with_timeout(self):
+        # Register callbacks 0, 1, 2, and 3. Callback 1 has a timeout.
+        # Wait for that timeout to expire, then do notify(2) and make
+        # sure everyone runs. Verifies that a timed-out callback does
+        # not count against the 'n' argument to notify().
+        c = locks.Condition()
+        self.record_done(c.wait(), 0)
+        self.record_done(c.wait(timedelta(seconds=0.01)), 1)
+        self.record_done(c.wait(), 2)
+        self.record_done(c.wait(), 3)
+
+        # Wait for callback 1 to time out.
+        yield gen.sleep(0.02)
+        self.assertEqual(["timeout"], self.history)
+
+        c.notify(2)
+        yield gen.sleep(0.01)
+        self.assertEqual(["timeout", 0, 2], self.history)
+        self.assertEqual(["timeout", 0, 2], self.history)
+        c.notify()
+        yield
+        self.assertEqual(["timeout", 0, 2, 3], self.history)
+
+    @gen_test
+    def test_notify_all_with_timeout(self):
+        c = locks.Condition()
+        self.record_done(c.wait(), 0)
+        self.record_done(c.wait(timedelta(seconds=0.01)), 1)
+        self.record_done(c.wait(), 2)
+
+        # Wait for callback 1 to time out.
+        yield gen.sleep(0.02)
+        self.assertEqual(["timeout"], self.history)
+
+        c.notify_all()
+        yield
+        self.assertEqual(["timeout", 0, 2], self.history)
+
+    @gen_test
+    def test_nested_notify(self):
+        # Ensure no notifications lost, even if notify() is reentered by a
+        # waiter calling notify().
+        c = locks.Condition()
+
+        # Three waiters.
+        futures = [asyncio.ensure_future(c.wait()) for _ in range(3)]
+
+        # First and second futures resolved. Second future reenters notify(),
+        # resolving third future.
+        futures[1].add_done_callback(lambda _: c.notify())
+        c.notify(2)
+        yield
+        self.assertTrue(all(f.done() for f in futures))
+
+    @gen_test
+    def test_garbage_collection(self):
+        # Test that timed-out waiters are occasionally cleaned from the queue.
+        c = locks.Condition()
+        for _ in range(101):
+            c.wait(timedelta(seconds=0.01))
+
+        future = asyncio.ensure_future(c.wait())
+        self.assertEqual(102, len(c._waiters))
+
+        # Let first 101 waiters time out, triggering a collection.
+        yield gen.sleep(0.02)
+        self.assertEqual(1, len(c._waiters))
+
+        # Final waiter is still active.
+        self.assertFalse(future.done())
+        c.notify()
+        self.assertTrue(future.done())
+
+
+class EventTest(AsyncTestCase):
+    def test_repr(self):
+        event = locks.Event()
+        self.assertTrue("clear" in str(event))
+        self.assertFalse("set" in str(event))
+        event.set()
+        self.assertFalse("clear" in str(event))
+        self.assertTrue("set" in str(event))
+
+    def test_event(self):
+        e = locks.Event()
+        future_0 = asyncio.ensure_future(e.wait())
+        e.set()
+        future_1 = asyncio.ensure_future(e.wait())
+        e.clear()
+        future_2 = asyncio.ensure_future(e.wait())
+
+        self.assertTrue(future_0.done())
+        self.assertTrue(future_1.done())
+        self.assertFalse(future_2.done())
+
+    @gen_test
+    def test_event_timeout(self):
+        e = locks.Event()
+        with self.assertRaises(TimeoutError):
+            yield e.wait(timedelta(seconds=0.01))
+
+        # After a timed-out waiter, normal operation works.
+        self.io_loop.add_timeout(timedelta(seconds=0.01), e.set)
+        yield e.wait(timedelta(seconds=1))
+
+    def test_event_set_multiple(self):
+        e = locks.Event()
+        e.set()
+        e.set()
+        self.assertTrue(e.is_set())
+
+    def test_event_wait_clear(self):
+        e = locks.Event()
+        f0 = asyncio.ensure_future(e.wait())
+        e.clear()
+        f1 = asyncio.ensure_future(e.wait())
+        e.set()
+        self.assertTrue(f0.done())
+        self.assertTrue(f1.done())
+
+
+class SemaphoreTest(AsyncTestCase):
+    def test_negative_value(self):
+        self.assertRaises(ValueError, locks.Semaphore, value=-1)
+
+    def test_repr(self):
+        sem = locks.Semaphore()
+        self.assertIn("Semaphore", repr(sem))
+        self.assertIn("unlocked,value:1", repr(sem))
+        sem.acquire()
+        self.assertIn("locked", repr(sem))
+        self.assertNotIn("waiters", repr(sem))
+        sem.acquire()
+        self.assertIn("waiters", repr(sem))
+
+    def test_acquire(self):
+        sem = locks.Semaphore()
+        f0 = asyncio.ensure_future(sem.acquire())
+        self.assertTrue(f0.done())
+
+        # Wait for release().
+        f1 = asyncio.ensure_future(sem.acquire())
+        self.assertFalse(f1.done())
+        f2 = asyncio.ensure_future(sem.acquire())
+        sem.release()
+        self.assertTrue(f1.done())
+        self.assertFalse(f2.done())
+        sem.release()
+        self.assertTrue(f2.done())
+
+        sem.release()
+        # Now acquire() is instant.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+        self.assertEqual(0, len(sem._waiters))
+
+    @gen_test
+    def test_acquire_timeout(self):
+        sem = locks.Semaphore(2)
+        yield sem.acquire()
+        yield sem.acquire()
+        acquire = sem.acquire(timedelta(seconds=0.01))
+        self.io_loop.call_later(0.02, sem.release)  # Too late.
+        yield gen.sleep(0.3)
+        with self.assertRaises(gen.TimeoutError):
+            yield acquire
+
+        sem.acquire()
+        f = asyncio.ensure_future(sem.acquire())
+        self.assertFalse(f.done())
+        sem.release()
+        self.assertTrue(f.done())
+
+    @gen_test
+    def test_acquire_timeout_preempted(self):
+        sem = locks.Semaphore(1)
+        yield sem.acquire()
+
+        # This fires before the wait times out.
+        self.io_loop.call_later(0.01, sem.release)
+        acquire = sem.acquire(timedelta(seconds=0.02))
+        yield gen.sleep(0.03)
+        yield acquire  # No TimeoutError.
+
+    def test_release_unacquired(self):
+        # Unbounded releases are allowed, and increment the semaphore's value.
+        sem = locks.Semaphore()
+        sem.release()
+        sem.release()
+
+        # Now the counter is 3. We can acquire three times before blocking.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+        self.assertFalse(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_garbage_collection(self):
+        # Test that timed-out waiters are occasionally cleaned from the queue.
+        sem = locks.Semaphore(value=0)
+        futures = [
+            asyncio.ensure_future(sem.acquire(timedelta(seconds=0.01)))
+            for _ in range(101)
+        ]
+
+        future = asyncio.ensure_future(sem.acquire())
+        self.assertEqual(102, len(sem._waiters))
+
+        # Let first 101 waiters time out, triggering a collection.
+        yield gen.sleep(0.02)
+        self.assertEqual(1, len(sem._waiters))
+
+        # Final waiter is still active.
+        self.assertFalse(future.done())
+        sem.release()
+        self.assertTrue(future.done())
+
+        # Prevent "Future exception was never retrieved" messages.
+        for future in futures:
+            self.assertRaises(TimeoutError, future.result)
+
+
+class SemaphoreContextManagerTest(AsyncTestCase):
+    @gen_test
+    def test_context_manager(self):
+        sem = locks.Semaphore()
+        with (yield sem.acquire()) as yielded:
+            self.assertTrue(yielded is None)
+
+        # Semaphore was released and can be acquired again.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_context_manager_async_await(self):
+        # Repeat the above test using 'async with'.
+        sem = locks.Semaphore()
+
+        async def f():
+            async with sem as yielded:
+                self.assertTrue(yielded is None)
+
+        yield f()
+
+        # Semaphore was released and can be acquired again.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_context_manager_exception(self):
+        sem = locks.Semaphore()
+        with self.assertRaises(ZeroDivisionError):
+            with (yield sem.acquire()):
+                1 / 0
+
+        # Semaphore was released and can be acquired again.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_context_manager_timeout(self):
+        sem = locks.Semaphore()
+        with (yield sem.acquire(timedelta(seconds=0.01))):
+            pass
+
+        # Semaphore was released and can be acquired again.
+        self.assertTrue(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_context_manager_timeout_error(self):
+        sem = locks.Semaphore(value=0)
+        with self.assertRaises(gen.TimeoutError):
+            with (yield sem.acquire(timedelta(seconds=0.01))):
+                pass
+
+        # Counter is still 0.
+        self.assertFalse(asyncio.ensure_future(sem.acquire()).done())
+
+    @gen_test
+    def test_context_manager_contended(self):
+        sem = locks.Semaphore()
+        history = []
+
+        @gen.coroutine
+        def f(index):
+            with (yield sem.acquire()):
+                history.append("acquired %d" % index)
+                yield gen.sleep(0.01)
+                history.append("release %d" % index)
+
+        yield [f(i) for i in range(2)]
+
+        expected_history = []
+        for i in range(2):
+            expected_history.extend(["acquired %d" % i, "release %d" % i])
+
+        self.assertEqual(expected_history, history)
+
+    @gen_test
+    def test_yield_sem(self):
+        # Ensure we catch a "with (yield sem)", which should be
+        # "with (yield sem.acquire())".
+        with self.assertRaises(gen.BadYieldError):
+            with (yield locks.Semaphore()):
+                pass
+
+    def test_context_manager_misuse(self):
+        # Ensure we catch a "with sem", which should be
+        # "with (yield sem.acquire())".
+        with self.assertRaises(RuntimeError):
+            with locks.Semaphore():
+                pass
+
+
+class BoundedSemaphoreTest(AsyncTestCase):
+    def test_release_unacquired(self):
+        sem = locks.BoundedSemaphore()
+        self.assertRaises(ValueError, sem.release)
+        # Value is 0.
+        sem.acquire()
+        # Block on acquire().
+        future = asyncio.ensure_future(sem.acquire())
+        self.assertFalse(future.done())
+        sem.release()
+        self.assertTrue(future.done())
+        # Value is 1.
+        sem.release()
+        self.assertRaises(ValueError, sem.release)
+
+
+class LockTests(AsyncTestCase):
+    def test_repr(self):
+        lock = locks.Lock()
+        # No errors.
+        repr(lock)
+        lock.acquire()
+        repr(lock)
+
+    def test_acquire_release(self):
+        lock = locks.Lock()
+        self.assertTrue(asyncio.ensure_future(lock.acquire()).done())
+        future = asyncio.ensure_future(lock.acquire())
+        self.assertFalse(future.done())
+        lock.release()
+        self.assertTrue(future.done())
+
+    @gen_test
+    def test_acquire_fifo(self):
+        lock = locks.Lock()
+        self.assertTrue(asyncio.ensure_future(lock.acquire()).done())
+        N = 5
+        history = []
+
+        @gen.coroutine
+        def f(idx):
+            with (yield lock.acquire()):
+                history.append(idx)
+
+        futures = [f(i) for i in range(N)]
+        self.assertFalse(any(future.done() for future in futures))
+        lock.release()
+        yield futures
+        self.assertEqual(list(range(N)), history)
+
+    @gen_test
+    def test_acquire_fifo_async_with(self):
+        # Repeat the above test using `async with lock:`
+        # instead of `with (yield lock.acquire()):`.
+        lock = locks.Lock()
+        self.assertTrue(asyncio.ensure_future(lock.acquire()).done())
+        N = 5
+        history = []
+
+        async def f(idx):
+            async with lock:
+                history.append(idx)
+
+        futures = [f(i) for i in range(N)]
+        lock.release()
+        yield futures
+        self.assertEqual(list(range(N)), history)
+
+    @gen_test
+    def test_acquire_timeout(self):
+        lock = locks.Lock()
+        lock.acquire()
+        with self.assertRaises(gen.TimeoutError):
+            yield lock.acquire(timeout=timedelta(seconds=0.01))
+
+        # Still locked.
+        self.assertFalse(asyncio.ensure_future(lock.acquire()).done())
+
+    def test_multi_release(self):
+        lock = locks.Lock()
+        self.assertRaises(RuntimeError, lock.release)
+        lock.acquire()
+        lock.release()
+        self.assertRaises(RuntimeError, lock.release)
+
+    @gen_test
+    def test_yield_lock(self):
+        # Ensure we catch a "with (yield lock)", which should be
+        # "with (yield lock.acquire())".
+        with self.assertRaises(gen.BadYieldError):
+            with (yield locks.Lock()):
+                pass
+
+    def test_context_manager_misuse(self):
+        # Ensure we catch a "with lock", which should be
+        # "with (yield lock.acquire())".
+        with self.assertRaises(RuntimeError):
+            with locks.Lock():
+                pass
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/log_test.py b/venv/lib/python3.9/site-packages/tornado/test/log_test.py
new file mode 100644
index 00000000..9130ae7e
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/log_test.py
@@ -0,0 +1,245 @@
+#
+# Copyright 2012 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+import contextlib
+import glob
+import logging
+import os
+import re
+import subprocess
+import sys
+import tempfile
+import unittest
+import warnings
+
+from tornado.escape import utf8
+from tornado.log import LogFormatter, define_logging_options, enable_pretty_logging
+from tornado.options import OptionParser
+from tornado.util import basestring_type
+
+
+@contextlib.contextmanager
+def ignore_bytes_warning():
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", category=BytesWarning)
+        yield
+
+
+class LogFormatterTest(unittest.TestCase):
+    # Matches the output of a single logging call (which may be multiple lines
+    # if a traceback was included, so we use the DOTALL option)
+    LINE_RE = re.compile(
+        b"(?s)\x01\\[E [0-9]{6} [0-9]{2}:[0-9]{2}:[0-9]{2} log_test:[0-9]+\\]\x02 (.*)"
+    )
+
+    def setUp(self):
+        self.formatter = LogFormatter(color=False)
+        # Fake color support.  We can't guarantee anything about the $TERM
+        # variable when the tests are run, so just patch in some values
+        # for testing.  (testing with color off fails to expose some potential
+        # encoding issues from the control characters)
+        self.formatter._colors = {logging.ERROR: "\u0001"}
+        self.formatter._normal = "\u0002"
+        # construct a Logger directly to bypass getLogger's caching
+        self.logger = logging.Logger("LogFormatterTest")
+        self.logger.propagate = False
+        self.tempdir = tempfile.mkdtemp()
+        self.filename = os.path.join(self.tempdir, "log.out")
+        self.handler = self.make_handler(self.filename)
+        self.handler.setFormatter(self.formatter)
+        self.logger.addHandler(self.handler)
+
+    def tearDown(self):
+        self.handler.close()
+        os.unlink(self.filename)
+        os.rmdir(self.tempdir)
+
+    def make_handler(self, filename):
+        # Base case: default setup without explicit encoding.
+        # In python 2, supports arbitrary byte strings and unicode objects
+        # that contain only ascii.  In python 3, supports ascii-only unicode
+        # strings (but byte strings will be repr'd automatically).
+        return logging.FileHandler(filename)
+
+    def get_output(self):
+        with open(self.filename, "rb") as f:
+            line = f.read().strip()
+            m = LogFormatterTest.LINE_RE.match(line)
+            if m:
+                return m.group(1)
+            else:
+                raise Exception("output didn't match regex: %r" % line)
+
+    def test_basic_logging(self):
+        self.logger.error("foo")
+        self.assertEqual(self.get_output(), b"foo")
+
+    def test_bytes_logging(self):
+        with ignore_bytes_warning():
+            # This will be "\xe9" on python 2 or "b'\xe9'" on python 3
+            self.logger.error(b"\xe9")
+            self.assertEqual(self.get_output(), utf8(repr(b"\xe9")))
+
+    def test_utf8_logging(self):
+        with ignore_bytes_warning():
+            self.logger.error("\u00e9".encode("utf8"))
+        if issubclass(bytes, basestring_type):
+            # on python 2, utf8 byte strings (and by extension ascii byte
+            # strings) are passed through as-is.
+            self.assertEqual(self.get_output(), utf8("\u00e9"))
+        else:
+            # on python 3, byte strings always get repr'd even if
+            # they're ascii-only, so this degenerates into another
+            # copy of test_bytes_logging.
+            self.assertEqual(self.get_output(), utf8(repr(utf8("\u00e9"))))
+
+    def test_bytes_exception_logging(self):
+        try:
+            raise Exception(b"\xe9")
+        except Exception:
+            self.logger.exception("caught exception")
+        # This will be "Exception: \xe9" on python 2 or
+        # "Exception: b'\xe9'" on python 3.
+        output = self.get_output()
+        self.assertRegex(output, rb"Exception.*\\xe9")
+        # The traceback contains newlines, which should not have been escaped.
+        self.assertNotIn(rb"\n", output)
+
+
+class UnicodeLogFormatterTest(LogFormatterTest):
+    def make_handler(self, filename):
+        # Adding an explicit encoding configuration allows non-ascii unicode
+        # strings in both python 2 and 3, without changing the behavior
+        # for byte strings.
+        return logging.FileHandler(filename, encoding="utf8")
+
+    def test_unicode_logging(self):
+        self.logger.error("\u00e9")
+        self.assertEqual(self.get_output(), utf8("\u00e9"))
+
+
+class EnablePrettyLoggingTest(unittest.TestCase):
+    def setUp(self):
+        super().setUp()
+        self.options = OptionParser()
+        define_logging_options(self.options)
+        self.logger = logging.Logger("tornado.test.log_test.EnablePrettyLoggingTest")
+        self.logger.propagate = False
+
+    def test_log_file(self):
+        tmpdir = tempfile.mkdtemp()
+        try:
+            self.options.log_file_prefix = tmpdir + "/test_log"
+            enable_pretty_logging(options=self.options, logger=self.logger)
+            self.assertEqual(1, len(self.logger.handlers))
+            self.logger.error("hello")
+            self.logger.handlers[0].flush()
+            filenames = glob.glob(tmpdir + "/test_log*")
+            self.assertEqual(1, len(filenames))
+            with open(filenames[0]) as f:
+                self.assertRegex(f.read(), r"^\[E [^]]*\] hello$")
+        finally:
+            for handler in self.logger.handlers:
+                handler.flush()
+                handler.close()
+            for filename in glob.glob(tmpdir + "/test_log*"):
+                os.unlink(filename)
+            os.rmdir(tmpdir)
+
+    def test_log_file_with_timed_rotating(self):
+        tmpdir = tempfile.mkdtemp()
+        try:
+            self.options.log_file_prefix = tmpdir + "/test_log"
+            self.options.log_rotate_mode = "time"
+            enable_pretty_logging(options=self.options, logger=self.logger)
+            self.logger.error("hello")
+            self.logger.handlers[0].flush()
+            filenames = glob.glob(tmpdir + "/test_log*")
+            self.assertEqual(1, len(filenames))
+            with open(filenames[0]) as f:
+                self.assertRegex(f.read(), r"^\[E [^]]*\] hello$")
+        finally:
+            for handler in self.logger.handlers:
+                handler.flush()
+                handler.close()
+            for filename in glob.glob(tmpdir + "/test_log*"):
+                os.unlink(filename)
+            os.rmdir(tmpdir)
+
+    def test_wrong_rotate_mode_value(self):
+        try:
+            self.options.log_file_prefix = "some_path"
+            self.options.log_rotate_mode = "wrong_mode"
+            self.assertRaises(
+                ValueError,
+                enable_pretty_logging,
+                options=self.options,
+                logger=self.logger,
+            )
+        finally:
+            for handler in self.logger.handlers:
+                handler.flush()
+                handler.close()
+
+
+class LoggingOptionTest(unittest.TestCase):
+    """Test the ability to enable and disable Tornado's logging hooks."""
+
+    def logs_present(self, statement, args=None):
+        # Each test may manipulate and/or parse the options and then logs
+        # a line at the 'info' level.  This level is ignored in the
+        # logging module by default, but Tornado turns it on by default
+        # so it is the easiest way to tell whether tornado's logging hooks
+        # ran.
+        IMPORT = "from tornado.options import options, parse_command_line"
+        LOG_INFO = 'import logging; logging.info("hello")'
+        program = ";".join([IMPORT, statement, LOG_INFO])
+        proc = subprocess.Popen(
+            [sys.executable, "-c", program] + (args or []),
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+        )
+        stdout, stderr = proc.communicate()
+        self.assertEqual(proc.returncode, 0, "process failed: %r" % stdout)
+        return b"hello" in stdout
+
+    def test_default(self):
+        self.assertFalse(self.logs_present("pass"))
+
+    def test_tornado_default(self):
+        self.assertTrue(self.logs_present("parse_command_line()"))
+
+    def test_disable_command_line(self):
+        self.assertFalse(self.logs_present("parse_command_line()", ["--logging=none"]))
+
+    def test_disable_command_line_case_insensitive(self):
+        self.assertFalse(self.logs_present("parse_command_line()", ["--logging=None"]))
+
+    def test_disable_code_string(self):
+        self.assertFalse(
+            self.logs_present('options.logging = "none"; parse_command_line()')
+        )
+
+    def test_disable_code_none(self):
+        self.assertFalse(
+            self.logs_present("options.logging = None; parse_command_line()")
+        )
+
+    def test_disable_override(self):
+        # command line trumps code defaults
+        self.assertTrue(
+            self.logs_present(
+                "options.logging = None; parse_command_line()", ["--logging=info"]
+            )
+        )
diff --git a/venv/lib/python3.9/site-packages/tornado/test/netutil_test.py b/venv/lib/python3.9/site-packages/tornado/test/netutil_test.py
new file mode 100644
index 00000000..b35b7947
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/netutil_test.py
@@ -0,0 +1,241 @@
+import errno
+import os
+import signal
+import socket
+from subprocess import Popen
+import sys
+import time
+import unittest
+
+from tornado.netutil import (
+    BlockingResolver,
+    OverrideResolver,
+    ThreadedResolver,
+    is_valid_ip,
+    bind_sockets,
+)
+from tornado.testing import AsyncTestCase, gen_test, bind_unused_port
+from tornado.test.util import skipIfNoNetwork
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import List  # noqa: F401
+
+try:
+    import pycares  # type: ignore
+except ImportError:
+    pycares = None
+else:
+    from tornado.platform.caresresolver import CaresResolver
+
+try:
+    import twisted  # type: ignore
+    import twisted.names  # type: ignore
+except ImportError:
+    twisted = None
+else:
+    from tornado.platform.twisted import TwistedResolver
+
+
+class _ResolverTestMixin(object):
+    resolver = None  # type: typing.Any
+
+    @gen_test
+    def test_localhost(self: typing.Any):
+        addrinfo = yield self.resolver.resolve("localhost", 80, socket.AF_UNSPEC)
+        # Most of the time localhost resolves to either the ipv4 loopback
+        # address alone, or ipv4+ipv6. But some versions of pycares will only
+        # return the ipv6 version, so we have to check for either one alone.
+        self.assertTrue(
+            ((socket.AF_INET, ("127.0.0.1", 80)) in addrinfo)
+            or ((socket.AF_INET6, ("::1", 80)) in addrinfo),
+            f"loopback address not found in {addrinfo}",
+        )
+
+
+# It is impossible to quickly and consistently generate an error in name
+# resolution, so test this case separately, using mocks as needed.
+class _ResolverErrorTestMixin(object):
+    resolver = None  # type: typing.Any
+
+    @gen_test
+    def test_bad_host(self: typing.Any):
+        with self.assertRaises(IOError):
+            yield self.resolver.resolve("an invalid domain", 80, socket.AF_UNSPEC)
+
+
+def _failing_getaddrinfo(*args):
+    """Dummy implementation of getaddrinfo for use in mocks"""
+    raise socket.gaierror(errno.EIO, "mock: lookup failed")
+
+
+@skipIfNoNetwork
+class BlockingResolverTest(AsyncTestCase, _ResolverTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = BlockingResolver()
+
+
+# getaddrinfo-based tests need mocking to reliably generate errors;
+# some configurations are slow to produce errors and take longer than
+# our default timeout.
+class BlockingResolverErrorTest(AsyncTestCase, _ResolverErrorTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = BlockingResolver()
+        self.real_getaddrinfo = socket.getaddrinfo
+        socket.getaddrinfo = _failing_getaddrinfo
+
+    def tearDown(self):
+        socket.getaddrinfo = self.real_getaddrinfo
+        super().tearDown()
+
+
+class OverrideResolverTest(AsyncTestCase, _ResolverTestMixin):
+    def setUp(self):
+        super().setUp()
+        mapping = {
+            ("google.com", 80): ("1.2.3.4", 80),
+            ("google.com", 80, socket.AF_INET): ("1.2.3.4", 80),
+            ("google.com", 80, socket.AF_INET6): (
+                "2a02:6b8:7c:40c:c51e:495f:e23a:3",
+                80,
+            ),
+        }
+        self.resolver = OverrideResolver(BlockingResolver(), mapping)
+
+    @gen_test
+    def test_resolve_multiaddr(self):
+        result = yield self.resolver.resolve("google.com", 80, socket.AF_INET)
+        self.assertIn((socket.AF_INET, ("1.2.3.4", 80)), result)
+
+        result = yield self.resolver.resolve("google.com", 80, socket.AF_INET6)
+        self.assertIn(
+            (socket.AF_INET6, ("2a02:6b8:7c:40c:c51e:495f:e23a:3", 80, 0, 0)), result
+        )
+
+
+@skipIfNoNetwork
+class ThreadedResolverTest(AsyncTestCase, _ResolverTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = ThreadedResolver()
+
+    def tearDown(self):
+        self.resolver.close()
+        super().tearDown()
+
+
+class ThreadedResolverErrorTest(AsyncTestCase, _ResolverErrorTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = BlockingResolver()
+        self.real_getaddrinfo = socket.getaddrinfo
+        socket.getaddrinfo = _failing_getaddrinfo
+
+    def tearDown(self):
+        socket.getaddrinfo = self.real_getaddrinfo
+        super().tearDown()
+
+
+@skipIfNoNetwork
+@unittest.skipIf(sys.platform == "win32", "preexec_fn not available on win32")
+class ThreadedResolverImportTest(unittest.TestCase):
+    def test_import(self):
+        TIMEOUT = 5
+
+        # Test for a deadlock when importing a module that runs the
+        # ThreadedResolver at import-time. See resolve_test.py for
+        # full explanation.
+        command = [sys.executable, "-c", "import tornado.test.resolve_test_helper"]
+
+        start = time.time()
+        popen = Popen(command, preexec_fn=lambda: signal.alarm(TIMEOUT))
+        while time.time() - start < TIMEOUT:
+            return_code = popen.poll()
+            if return_code is not None:
+                self.assertEqual(0, return_code)
+                return  # Success.
+            time.sleep(0.05)
+
+        self.fail("import timed out")
+
+
+# We do not test errors with CaresResolver:
+# Some DNS-hijacking ISPs (e.g. Time Warner) return non-empty results
+# with an NXDOMAIN status code.  Most resolvers treat this as an error;
+# C-ares returns the results, making the "bad_host" tests unreliable.
+# C-ares will try to resolve even malformed names, such as the
+# name with spaces used in this test.
+@skipIfNoNetwork
+@unittest.skipIf(pycares is None, "pycares module not present")
+@unittest.skipIf(sys.platform == "win32", "pycares doesn't return loopback on windows")
+@unittest.skipIf(sys.platform == "darwin", "pycares doesn't return 127.0.0.1 on darwin")
+class CaresResolverTest(AsyncTestCase, _ResolverTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = CaresResolver()
+
+
+# TwistedResolver produces consistent errors in our test cases so we
+# could test the regular and error cases in the same class. However,
+# in the error cases it appears that cleanup of socket objects is
+# handled asynchronously and occasionally results in "unclosed socket"
+# warnings if not given time to shut down (and there is no way to
+# explicitly shut it down). This makes the test flaky, so we do not
+# test error cases here.
+@skipIfNoNetwork
+@unittest.skipIf(twisted is None, "twisted module not present")
+@unittest.skipIf(
+    getattr(twisted, "__version__", "0.0") < "12.1", "old version of twisted"
+)
+@unittest.skipIf(sys.platform == "win32", "twisted resolver hangs on windows")
+class TwistedResolverTest(AsyncTestCase, _ResolverTestMixin):
+    def setUp(self):
+        super().setUp()
+        self.resolver = TwistedResolver()
+
+
+class IsValidIPTest(unittest.TestCase):
+    def test_is_valid_ip(self):
+        self.assertTrue(is_valid_ip("127.0.0.1"))
+        self.assertTrue(is_valid_ip("4.4.4.4"))
+        self.assertTrue(is_valid_ip("::1"))
+        self.assertTrue(is_valid_ip("2620:0:1cfe:face:b00c::3"))
+        self.assertTrue(not is_valid_ip("www.google.com"))
+        self.assertTrue(not is_valid_ip("localhost"))
+        self.assertTrue(not is_valid_ip("4.4.4.4<"))
+        self.assertTrue(not is_valid_ip(" 127.0.0.1"))
+        self.assertTrue(not is_valid_ip(""))
+        self.assertTrue(not is_valid_ip(" "))
+        self.assertTrue(not is_valid_ip("\n"))
+        self.assertTrue(not is_valid_ip("\x00"))
+        self.assertTrue(not is_valid_ip("a" * 100))
+
+
+class TestPortAllocation(unittest.TestCase):
+    def test_same_port_allocation(self):
+        if "TRAVIS" in os.environ:
+            self.skipTest("dual-stack servers often have port conflicts on travis")
+        sockets = bind_sockets(0, "localhost")
+        try:
+            port = sockets[0].getsockname()[1]
+            self.assertTrue(all(s.getsockname()[1] == port for s in sockets[1:]))
+        finally:
+            for sock in sockets:
+                sock.close()
+
+    @unittest.skipIf(
+        not hasattr(socket, "SO_REUSEPORT"), "SO_REUSEPORT is not supported"
+    )
+    def test_reuse_port(self):
+        sockets = []  # type: List[socket.socket]
+        socket, port = bind_unused_port(reuse_port=True)
+        try:
+            sockets = bind_sockets(port, "127.0.0.1", reuse_port=True)
+            self.assertTrue(all(s.getsockname()[1] == port for s in sockets))
+        finally:
+            socket.close()
+            for sock in sockets:
+                sock.close()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/options_test.cfg b/venv/lib/python3.9/site-packages/tornado/test/options_test.cfg
new file mode 100644
index 00000000..4ead46a4
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/options_test.cfg
@@ -0,0 +1,7 @@
+port=443
+port=443
+username='李康'
+
+foo_bar='a'
+
+my_path = __file__
diff --git a/venv/lib/python3.9/site-packages/tornado/test/options_test.py b/venv/lib/python3.9/site-packages/tornado/test/options_test.py
new file mode 100644
index 00000000..6f4021c6
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/options_test.py
@@ -0,0 +1,329 @@
+import datetime
+from io import StringIO
+import os
+import sys
+from unittest import mock
+import unittest
+
+from tornado.options import OptionParser, Error
+from tornado.util import basestring_type
+from tornado.test.util import subTest
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import List  # noqa: F401
+
+
+class Email(object):
+    def __init__(self, value):
+        if isinstance(value, str) and "@" in value:
+            self._value = value
+        else:
+            raise ValueError()
+
+    @property
+    def value(self):
+        return self._value
+
+
+class OptionsTest(unittest.TestCase):
+    def test_parse_command_line(self):
+        options = OptionParser()
+        options.define("port", default=80)
+        options.parse_command_line(["main.py", "--port=443"])
+        self.assertEqual(options.port, 443)
+
+    def test_parse_config_file(self):
+        options = OptionParser()
+        options.define("port", default=80)
+        options.define("username", default="foo")
+        options.define("my_path")
+        config_path = os.path.join(
+            os.path.dirname(os.path.abspath(__file__)), "options_test.cfg"
+        )
+        options.parse_config_file(config_path)
+        self.assertEqual(options.port, 443)
+        self.assertEqual(options.username, "李康")
+        self.assertEqual(options.my_path, config_path)
+
+    def test_parse_callbacks(self):
+        options = OptionParser()
+        self.called = False
+
+        def callback():
+            self.called = True
+
+        options.add_parse_callback(callback)
+
+        # non-final parse doesn't run callbacks
+        options.parse_command_line(["main.py"], final=False)
+        self.assertFalse(self.called)
+
+        # final parse does
+        options.parse_command_line(["main.py"])
+        self.assertTrue(self.called)
+
+        # callbacks can be run more than once on the same options
+        # object if there are multiple final parses
+        self.called = False
+        options.parse_command_line(["main.py"])
+        self.assertTrue(self.called)
+
+    def test_help(self):
+        options = OptionParser()
+        try:
+            orig_stderr = sys.stderr
+            sys.stderr = StringIO()
+            with self.assertRaises(SystemExit):
+                options.parse_command_line(["main.py", "--help"])
+            usage = sys.stderr.getvalue()
+        finally:
+            sys.stderr = orig_stderr
+        self.assertIn("Usage:", usage)
+
+    def test_subcommand(self):
+        base_options = OptionParser()
+        base_options.define("verbose", default=False)
+        sub_options = OptionParser()
+        sub_options.define("foo", type=str)
+        rest = base_options.parse_command_line(
+            ["main.py", "--verbose", "subcommand", "--foo=bar"]
+        )
+        self.assertEqual(rest, ["subcommand", "--foo=bar"])
+        self.assertTrue(base_options.verbose)
+        rest2 = sub_options.parse_command_line(rest)
+        self.assertEqual(rest2, [])
+        self.assertEqual(sub_options.foo, "bar")
+
+        # the two option sets are distinct
+        try:
+            orig_stderr = sys.stderr
+            sys.stderr = StringIO()
+            with self.assertRaises(Error):
+                sub_options.parse_command_line(["subcommand", "--verbose"])
+        finally:
+            sys.stderr = orig_stderr
+
+    def test_setattr(self):
+        options = OptionParser()
+        options.define("foo", default=1, type=int)
+        options.foo = 2
+        self.assertEqual(options.foo, 2)
+
+    def test_setattr_type_check(self):
+        # setattr requires that options be the right type and doesn't
+        # parse from string formats.
+        options = OptionParser()
+        options.define("foo", default=1, type=int)
+        with self.assertRaises(Error):
+            options.foo = "2"
+
+    def test_setattr_with_callback(self):
+        values = []  # type: List[int]
+        options = OptionParser()
+        options.define("foo", default=1, type=int, callback=values.append)
+        options.foo = 2
+        self.assertEqual(values, [2])
+
+    def _sample_options(self):
+        options = OptionParser()
+        options.define("a", default=1)
+        options.define("b", default=2)
+        return options
+
+    def test_iter(self):
+        options = self._sample_options()
+        # OptionParsers always define 'help'.
+        self.assertEqual(set(["a", "b", "help"]), set(iter(options)))
+
+    def test_getitem(self):
+        options = self._sample_options()
+        self.assertEqual(1, options["a"])
+
+    def test_setitem(self):
+        options = OptionParser()
+        options.define("foo", default=1, type=int)
+        options["foo"] = 2
+        self.assertEqual(options["foo"], 2)
+
+    def test_items(self):
+        options = self._sample_options()
+        # OptionParsers always define 'help'.
+        expected = [("a", 1), ("b", 2), ("help", options.help)]
+        actual = sorted(options.items())
+        self.assertEqual(expected, actual)
+
+    def test_as_dict(self):
+        options = self._sample_options()
+        expected = {"a": 1, "b": 2, "help": options.help}
+        self.assertEqual(expected, options.as_dict())
+
+    def test_group_dict(self):
+        options = OptionParser()
+        options.define("a", default=1)
+        options.define("b", group="b_group", default=2)
+
+        frame = sys._getframe(0)
+        this_file = frame.f_code.co_filename
+        self.assertEqual(set(["b_group", "", this_file]), options.groups())
+
+        b_group_dict = options.group_dict("b_group")
+        self.assertEqual({"b": 2}, b_group_dict)
+
+        self.assertEqual({}, options.group_dict("nonexistent"))
+
+    def test_mock_patch(self):
+        # ensure that our setattr hooks don't interfere with mock.patch
+        options = OptionParser()
+        options.define("foo", default=1)
+        options.parse_command_line(["main.py", "--foo=2"])
+        self.assertEqual(options.foo, 2)
+
+        with mock.patch.object(options.mockable(), "foo", 3):
+            self.assertEqual(options.foo, 3)
+        self.assertEqual(options.foo, 2)
+
+        # Try nested patches mixed with explicit sets
+        with mock.patch.object(options.mockable(), "foo", 4):
+            self.assertEqual(options.foo, 4)
+            options.foo = 5
+            self.assertEqual(options.foo, 5)
+            with mock.patch.object(options.mockable(), "foo", 6):
+                self.assertEqual(options.foo, 6)
+            self.assertEqual(options.foo, 5)
+        self.assertEqual(options.foo, 2)
+
+    def _define_options(self):
+        options = OptionParser()
+        options.define("str", type=str)
+        options.define("basestring", type=basestring_type)
+        options.define("int", type=int)
+        options.define("float", type=float)
+        options.define("datetime", type=datetime.datetime)
+        options.define("timedelta", type=datetime.timedelta)
+        options.define("email", type=Email)
+        options.define("list-of-int", type=int, multiple=True)
+        options.define("list-of-str", type=str, multiple=True)
+        return options
+
+    def _check_options_values(self, options):
+        self.assertEqual(options.str, "asdf")
+        self.assertEqual(options.basestring, "qwer")
+        self.assertEqual(options.int, 42)
+        self.assertEqual(options.float, 1.5)
+        self.assertEqual(options.datetime, datetime.datetime(2013, 4, 28, 5, 16))
+        self.assertEqual(options.timedelta, datetime.timedelta(seconds=45))
+        self.assertEqual(options.email.value, "tornado@web.com")
+        self.assertTrue(isinstance(options.email, Email))
+        self.assertEqual(options.list_of_int, [1, 2, 3])
+        self.assertEqual(options.list_of_str, ["a", "b", "c"])
+
+    def test_types(self):
+        options = self._define_options()
+        options.parse_command_line(
+            [
+                "main.py",
+                "--str=asdf",
+                "--basestring=qwer",
+                "--int=42",
+                "--float=1.5",
+                "--datetime=2013-04-28 05:16",
+                "--timedelta=45s",
+                "--email=tornado@web.com",
+                "--list-of-int=1,2,3",
+                "--list-of-str=a,b,c",
+            ]
+        )
+        self._check_options_values(options)
+
+    def test_types_with_conf_file(self):
+        for config_file_name in (
+            "options_test_types.cfg",
+            "options_test_types_str.cfg",
+        ):
+            options = self._define_options()
+            options.parse_config_file(
+                os.path.join(os.path.dirname(__file__), config_file_name)
+            )
+            self._check_options_values(options)
+
+    def test_multiple_string(self):
+        options = OptionParser()
+        options.define("foo", type=str, multiple=True)
+        options.parse_command_line(["main.py", "--foo=a,b,c"])
+        self.assertEqual(options.foo, ["a", "b", "c"])
+
+    def test_multiple_int(self):
+        options = OptionParser()
+        options.define("foo", type=int, multiple=True)
+        options.parse_command_line(["main.py", "--foo=1,3,5:7"])
+        self.assertEqual(options.foo, [1, 3, 5, 6, 7])
+
+    def test_error_redefine(self):
+        options = OptionParser()
+        options.define("foo")
+        with self.assertRaises(Error) as cm:
+            options.define("foo")
+        self.assertRegex(str(cm.exception), "Option.*foo.*already defined")
+
+    def test_error_redefine_underscore(self):
+        # Ensure that the dash/underscore normalization doesn't
+        # interfere with the redefinition error.
+        tests = [
+            ("foo-bar", "foo-bar"),
+            ("foo_bar", "foo_bar"),
+            ("foo-bar", "foo_bar"),
+            ("foo_bar", "foo-bar"),
+        ]
+        for a, b in tests:
+            with subTest(self, a=a, b=b):
+                options = OptionParser()
+                options.define(a)
+                with self.assertRaises(Error) as cm:
+                    options.define(b)
+                self.assertRegex(str(cm.exception), "Option.*foo.bar.*already defined")
+
+    def test_dash_underscore_cli(self):
+        # Dashes and underscores should be interchangeable.
+        for defined_name in ["foo-bar", "foo_bar"]:
+            for flag in ["--foo-bar=a", "--foo_bar=a"]:
+                options = OptionParser()
+                options.define(defined_name)
+                options.parse_command_line(["main.py", flag])
+                # Attr-style access always uses underscores.
+                self.assertEqual(options.foo_bar, "a")
+                # Dict-style access allows both.
+                self.assertEqual(options["foo-bar"], "a")
+                self.assertEqual(options["foo_bar"], "a")
+
+    def test_dash_underscore_file(self):
+        # No matter how an option was defined, it can be set with underscores
+        # in a config file.
+        for defined_name in ["foo-bar", "foo_bar"]:
+            options = OptionParser()
+            options.define(defined_name)
+            options.parse_config_file(
+                os.path.join(os.path.dirname(__file__), "options_test.cfg")
+            )
+            self.assertEqual(options.foo_bar, "a")
+
+    def test_dash_underscore_introspection(self):
+        # Original names are preserved in introspection APIs.
+        options = OptionParser()
+        options.define("with-dash", group="g")
+        options.define("with_underscore", group="g")
+        all_options = ["help", "with-dash", "with_underscore"]
+        self.assertEqual(sorted(options), all_options)
+        self.assertEqual(sorted(k for (k, v) in options.items()), all_options)
+        self.assertEqual(sorted(options.as_dict().keys()), all_options)
+
+        self.assertEqual(
+            sorted(options.group_dict("g")), ["with-dash", "with_underscore"]
+        )
+
+        # --help shows CLI-style names with dashes.
+        buf = StringIO()
+        options.print_help(buf)
+        self.assertIn("--with-dash", buf.getvalue())
+        self.assertIn("--with-underscore", buf.getvalue())
diff --git a/venv/lib/python3.9/site-packages/tornado/test/options_test_types.cfg b/venv/lib/python3.9/site-packages/tornado/test/options_test_types.cfg
new file mode 100644
index 00000000..9dfd9220
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/options_test_types.cfg
@@ -0,0 +1,12 @@
+from datetime import datetime, timedelta
+from tornado.test.options_test import Email
+
+str = 'asdf'
+basestring = 'qwer'
+int = 42
+float = 1.5
+datetime = datetime(2013, 4, 28, 5, 16)
+timedelta = timedelta(0, 45)
+email = Email('tornado@web.com')
+list_of_int = [1, 2, 3]
+list_of_str = ["a", "b", "c"]
diff --git a/venv/lib/python3.9/site-packages/tornado/test/options_test_types_str.cfg b/venv/lib/python3.9/site-packages/tornado/test/options_test_types_str.cfg
new file mode 100644
index 00000000..b07d6428
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/options_test_types_str.cfg
@@ -0,0 +1,9 @@
+str = 'asdf'
+basestring = 'qwer'
+int = 42
+float = 1.5
+datetime = '2013-04-28 05:16'
+timedelta = '45s'
+email = 'tornado@web.com'
+list_of_int = '1,2,3'
+list_of_str = 'a,b,c'
diff --git a/venv/lib/python3.9/site-packages/tornado/test/process_test.py b/venv/lib/python3.9/site-packages/tornado/test/process_test.py
new file mode 100644
index 00000000..ab290085
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/process_test.py
@@ -0,0 +1,274 @@
+import asyncio
+import logging
+import os
+import signal
+import subprocess
+import sys
+import time
+import unittest
+
+from tornado.httpclient import HTTPClient, HTTPError
+from tornado.httpserver import HTTPServer
+from tornado.ioloop import IOLoop
+from tornado.log import gen_log
+from tornado.process import fork_processes, task_id, Subprocess
+from tornado.simple_httpclient import SimpleAsyncHTTPClient
+from tornado.testing import bind_unused_port, ExpectLog, AsyncTestCase, gen_test
+from tornado.test.util import skipIfNonUnix
+from tornado.web import RequestHandler, Application
+
+
+# Not using AsyncHTTPTestCase because we need control over the IOLoop.
+@skipIfNonUnix
+class ProcessTest(unittest.TestCase):
+    def get_app(self):
+        class ProcessHandler(RequestHandler):
+            def get(self):
+                if self.get_argument("exit", None):
+                    # must use os._exit instead of sys.exit so unittest's
+                    # exception handler doesn't catch it
+                    os._exit(int(self.get_argument("exit")))
+                if self.get_argument("signal", None):
+                    os.kill(os.getpid(), int(self.get_argument("signal")))
+                self.write(str(os.getpid()))
+
+        return Application([("/", ProcessHandler)])
+
+    def tearDown(self):
+        if task_id() is not None:
+            # We're in a child process, and probably got to this point
+            # via an uncaught exception.  If we return now, both
+            # processes will continue with the rest of the test suite.
+            # Exit now so the parent process will restart the child
+            # (since we don't have a clean way to signal failure to
+            # the parent that won't restart)
+            logging.error("aborting child process from tearDown")
+            logging.shutdown()
+            os._exit(1)
+        # In the surviving process, clear the alarm we set earlier
+        signal.alarm(0)
+        super().tearDown()
+
+    def test_multi_process(self):
+        # This test doesn't work on twisted because we use the global
+        # reactor and don't restore it to a sane state after the fork
+        # (asyncio has the same issue, but we have a special case in
+        # place for it).
+        with ExpectLog(
+            gen_log, "(Starting .* processes|child .* exited|uncaught exception)"
+        ):
+            sock, port = bind_unused_port()
+
+            def get_url(path):
+                return "http://127.0.0.1:%d%s" % (port, path)
+
+            # ensure that none of these processes live too long
+            signal.alarm(5)  # master process
+            try:
+                id = fork_processes(3, max_restarts=3)
+                self.assertTrue(id is not None)
+                signal.alarm(5)  # child processes
+            except SystemExit as e:
+                # if we exit cleanly from fork_processes, all the child processes
+                # finished with status 0
+                self.assertEqual(e.code, 0)
+                self.assertTrue(task_id() is None)
+                sock.close()
+                return
+            try:
+                if id in (0, 1):
+                    self.assertEqual(id, task_id())
+
+                    async def f():
+                        server = HTTPServer(self.get_app())
+                        server.add_sockets([sock])
+                        await asyncio.Event().wait()
+
+                    asyncio.run(f())
+                elif id == 2:
+                    self.assertEqual(id, task_id())
+                    sock.close()
+                    # Always use SimpleAsyncHTTPClient here; the curl
+                    # version appears to get confused sometimes if the
+                    # connection gets closed before it's had a chance to
+                    # switch from writing mode to reading mode.
+                    client = HTTPClient(SimpleAsyncHTTPClient)
+
+                    def fetch(url, fail_ok=False):
+                        try:
+                            return client.fetch(get_url(url))
+                        except HTTPError as e:
+                            if not (fail_ok and e.code == 599):
+                                raise
+
+                    # Make two processes exit abnormally
+                    fetch("/?exit=2", fail_ok=True)
+                    fetch("/?exit=3", fail_ok=True)
+
+                    # They've been restarted, so a new fetch will work
+                    int(fetch("/").body)
+
+                    # Now the same with signals
+                    # Disabled because on the mac a process dying with a signal
+                    # can trigger an "Application exited abnormally; send error
+                    # report to Apple?" prompt.
+                    # fetch("/?signal=%d" % signal.SIGTERM, fail_ok=True)
+                    # fetch("/?signal=%d" % signal.SIGABRT, fail_ok=True)
+                    # int(fetch("/").body)
+
+                    # Now kill them normally so they won't be restarted
+                    fetch("/?exit=0", fail_ok=True)
+                    # One process left; watch it's pid change
+                    pid = int(fetch("/").body)
+                    fetch("/?exit=4", fail_ok=True)
+                    pid2 = int(fetch("/").body)
+                    self.assertNotEqual(pid, pid2)
+
+                    # Kill the last one so we shut down cleanly
+                    fetch("/?exit=0", fail_ok=True)
+
+                    os._exit(0)
+            except Exception:
+                logging.error("exception in child process %d", id, exc_info=True)
+                raise
+
+
+@skipIfNonUnix
+class SubprocessTest(AsyncTestCase):
+    def term_and_wait(self, subproc):
+        subproc.proc.terminate()
+        subproc.proc.wait()
+
+    @gen_test
+    def test_subprocess(self):
+        if IOLoop.configured_class().__name__.endswith("LayeredTwistedIOLoop"):
+            # This test fails non-deterministically with LayeredTwistedIOLoop.
+            # (the read_until('\n') returns '\n' instead of 'hello\n')
+            # This probably indicates a problem with either TornadoReactor
+            # or TwistedIOLoop, but I haven't been able to track it down
+            # and for now this is just causing spurious travis-ci failures.
+            raise unittest.SkipTest(
+                "Subprocess tests not compatible with " "LayeredTwistedIOLoop"
+            )
+        subproc = Subprocess(
+            [sys.executable, "-u", "-i"],
+            stdin=Subprocess.STREAM,
+            stdout=Subprocess.STREAM,
+            stderr=subprocess.STDOUT,
+        )
+        self.addCleanup(lambda: self.term_and_wait(subproc))
+        self.addCleanup(subproc.stdout.close)
+        self.addCleanup(subproc.stdin.close)
+        yield subproc.stdout.read_until(b">>> ")
+        subproc.stdin.write(b"print('hello')\n")
+        data = yield subproc.stdout.read_until(b"\n")
+        self.assertEqual(data, b"hello\n")
+
+        yield subproc.stdout.read_until(b">>> ")
+        subproc.stdin.write(b"raise SystemExit\n")
+        data = yield subproc.stdout.read_until_close()
+        self.assertEqual(data, b"")
+
+    @gen_test
+    def test_close_stdin(self):
+        # Close the parent's stdin handle and see that the child recognizes it.
+        subproc = Subprocess(
+            [sys.executable, "-u", "-i"],
+            stdin=Subprocess.STREAM,
+            stdout=Subprocess.STREAM,
+            stderr=subprocess.STDOUT,
+        )
+        self.addCleanup(lambda: self.term_and_wait(subproc))
+        yield subproc.stdout.read_until(b">>> ")
+        subproc.stdin.close()
+        data = yield subproc.stdout.read_until_close()
+        self.assertEqual(data, b"\n")
+
+    @gen_test
+    def test_stderr(self):
+        # This test is mysteriously flaky on twisted: it succeeds, but logs
+        # an error of EBADF on closing a file descriptor.
+        subproc = Subprocess(
+            [sys.executable, "-u", "-c", r"import sys; sys.stderr.write('hello\n')"],
+            stderr=Subprocess.STREAM,
+        )
+        self.addCleanup(lambda: self.term_and_wait(subproc))
+        data = yield subproc.stderr.read_until(b"\n")
+        self.assertEqual(data, b"hello\n")
+        # More mysterious EBADF: This fails if done with self.addCleanup instead of here.
+        subproc.stderr.close()
+
+    def test_sigchild(self):
+        Subprocess.initialize()
+        self.addCleanup(Subprocess.uninitialize)
+        subproc = Subprocess([sys.executable, "-c", "pass"])
+        subproc.set_exit_callback(self.stop)
+        ret = self.wait()
+        self.assertEqual(ret, 0)
+        self.assertEqual(subproc.returncode, ret)
+
+    @gen_test
+    def test_sigchild_future(self):
+        Subprocess.initialize()
+        self.addCleanup(Subprocess.uninitialize)
+        subproc = Subprocess([sys.executable, "-c", "pass"])
+        ret = yield subproc.wait_for_exit()
+        self.assertEqual(ret, 0)
+        self.assertEqual(subproc.returncode, ret)
+
+    def test_sigchild_signal(self):
+        Subprocess.initialize()
+        self.addCleanup(Subprocess.uninitialize)
+        subproc = Subprocess(
+            [sys.executable, "-c", "import time; time.sleep(30)"],
+            stdout=Subprocess.STREAM,
+        )
+        self.addCleanup(subproc.stdout.close)
+        subproc.set_exit_callback(self.stop)
+
+        # For unclear reasons, killing a process too soon after
+        # creating it can result in an exit status corresponding to
+        # SIGKILL instead of the actual signal involved. This has been
+        # observed on macOS 10.15 with Python 3.8 installed via brew,
+        # but not with the system-installed Python 3.7.
+        time.sleep(0.1)
+
+        os.kill(subproc.pid, signal.SIGTERM)
+        try:
+            ret = self.wait()
+        except AssertionError:
+            # We failed to get the termination signal. This test is
+            # occasionally flaky on pypy, so try to get a little more
+            # information: did the process close its stdout
+            # (indicating that the problem is in the parent process's
+            # signal handling) or did the child process somehow fail
+            # to terminate?
+            fut = subproc.stdout.read_until_close()
+            fut.add_done_callback(lambda f: self.stop())  # type: ignore
+            try:
+                self.wait()
+            except AssertionError:
+                raise AssertionError("subprocess failed to terminate")
+            else:
+                raise AssertionError(
+                    "subprocess closed stdout but failed to " "get termination signal"
+                )
+        self.assertEqual(subproc.returncode, ret)
+        self.assertEqual(ret, -signal.SIGTERM)
+
+    @gen_test
+    def test_wait_for_exit_raise(self):
+        Subprocess.initialize()
+        self.addCleanup(Subprocess.uninitialize)
+        subproc = Subprocess([sys.executable, "-c", "import sys; sys.exit(1)"])
+        with self.assertRaises(subprocess.CalledProcessError) as cm:
+            yield subproc.wait_for_exit()
+        self.assertEqual(cm.exception.returncode, 1)
+
+    @gen_test
+    def test_wait_for_exit_raise_disabled(self):
+        Subprocess.initialize()
+        self.addCleanup(Subprocess.uninitialize)
+        subproc = Subprocess([sys.executable, "-c", "import sys; sys.exit(1)"])
+        ret = yield subproc.wait_for_exit(raise_error=False)
+        self.assertEqual(ret, 1)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/queues_test.py b/venv/lib/python3.9/site-packages/tornado/test/queues_test.py
new file mode 100644
index 00000000..98a29a8d
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/queues_test.py
@@ -0,0 +1,431 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import asyncio
+from datetime import timedelta
+from random import random
+import unittest
+
+from tornado import gen, queues
+from tornado.gen import TimeoutError
+from tornado.testing import gen_test, AsyncTestCase
+
+
+class QueueBasicTest(AsyncTestCase):
+    def test_repr_and_str(self):
+        q = queues.Queue(maxsize=1)  # type: queues.Queue[None]
+        self.assertIn(hex(id(q)), repr(q))
+        self.assertNotIn(hex(id(q)), str(q))
+        q.get()
+
+        for q_str in repr(q), str(q):
+            self.assertTrue(q_str.startswith("<Queue"))
+            self.assertIn("maxsize=1", q_str)
+            self.assertIn("getters[1]", q_str)
+            self.assertNotIn("putters", q_str)
+            self.assertNotIn("tasks", q_str)
+
+        q.put(None)
+        q.put(None)
+        # Now the queue is full, this putter blocks.
+        q.put(None)
+
+        for q_str in repr(q), str(q):
+            self.assertNotIn("getters", q_str)
+            self.assertIn("putters[1]", q_str)
+            self.assertIn("tasks=2", q_str)
+
+    def test_order(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        for i in [1, 3, 2]:
+            q.put_nowait(i)
+
+        items = [q.get_nowait() for _ in range(3)]
+        self.assertEqual([1, 3, 2], items)
+
+    @gen_test
+    def test_maxsize(self):
+        self.assertRaises(TypeError, queues.Queue, maxsize=None)
+        self.assertRaises(ValueError, queues.Queue, maxsize=-1)
+
+        q = queues.Queue(maxsize=2)  # type: queues.Queue[int]
+        self.assertTrue(q.empty())
+        self.assertFalse(q.full())
+        self.assertEqual(2, q.maxsize)
+        self.assertTrue(q.put(0).done())
+        self.assertTrue(q.put(1).done())
+        self.assertFalse(q.empty())
+        self.assertTrue(q.full())
+        put2 = q.put(2)
+        self.assertFalse(put2.done())
+        self.assertEqual(0, (yield q.get()))  # Make room.
+        self.assertTrue(put2.done())
+        self.assertFalse(q.empty())
+        self.assertTrue(q.full())
+
+
+class QueueGetTest(AsyncTestCase):
+    @gen_test
+    def test_blocking_get(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        q.put_nowait(0)
+        self.assertEqual(0, (yield q.get()))
+
+    def test_nonblocking_get(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        q.put_nowait(0)
+        self.assertEqual(0, q.get_nowait())
+
+    def test_nonblocking_get_exception(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        self.assertRaises(queues.QueueEmpty, q.get_nowait)
+
+    @gen_test
+    def test_get_with_putters(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        q.put_nowait(0)
+        put = q.put(1)
+        self.assertEqual(0, (yield q.get()))
+        self.assertIsNone((yield put))
+
+    @gen_test
+    def test_blocking_get_wait(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        q.put(0)
+        self.io_loop.call_later(0.01, q.put_nowait, 1)
+        self.io_loop.call_later(0.02, q.put_nowait, 2)
+        self.assertEqual(0, (yield q.get(timeout=timedelta(seconds=1))))
+        self.assertEqual(1, (yield q.get(timeout=timedelta(seconds=1))))
+
+    @gen_test
+    def test_get_timeout(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        get_timeout = q.get(timeout=timedelta(seconds=0.01))
+        get = q.get()
+        with self.assertRaises(TimeoutError):
+            yield get_timeout
+
+        q.put_nowait(0)
+        self.assertEqual(0, (yield get))
+
+    @gen_test
+    def test_get_timeout_preempted(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        get = q.get(timeout=timedelta(seconds=0.01))
+        q.put(0)
+        yield gen.sleep(0.02)
+        self.assertEqual(0, (yield get))
+
+    @gen_test
+    def test_get_clears_timed_out_putters(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        # First putter succeeds, remainder block.
+        putters = [q.put(i, timedelta(seconds=0.01)) for i in range(10)]
+        put = q.put(10)
+        self.assertEqual(10, len(q._putters))
+        yield gen.sleep(0.02)
+        self.assertEqual(10, len(q._putters))
+        self.assertFalse(put.done())  # Final waiter is still active.
+        q.put(11)
+        self.assertEqual(0, (yield q.get()))  # get() clears the waiters.
+        self.assertEqual(1, len(q._putters))
+        for putter in putters[1:]:
+            self.assertRaises(TimeoutError, putter.result)
+
+    @gen_test
+    def test_get_clears_timed_out_getters(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        getters = [
+            asyncio.ensure_future(q.get(timedelta(seconds=0.01))) for _ in range(10)
+        ]
+        get = asyncio.ensure_future(q.get())
+        self.assertEqual(11, len(q._getters))
+        yield gen.sleep(0.02)
+        self.assertEqual(11, len(q._getters))
+        self.assertFalse(get.done())  # Final waiter is still active.
+        q.get()  # get() clears the waiters.
+        self.assertEqual(2, len(q._getters))
+        for getter in getters:
+            self.assertRaises(TimeoutError, getter.result)
+
+    @gen_test
+    def test_async_for(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        for i in range(5):
+            q.put(i)
+
+        async def f():
+            results = []
+            async for i in q:
+                results.append(i)
+                if i == 4:
+                    return results
+
+        results = yield f()
+        self.assertEqual(results, list(range(5)))
+
+
+class QueuePutTest(AsyncTestCase):
+    @gen_test
+    def test_blocking_put(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        q.put(0)
+        self.assertEqual(0, q.get_nowait())
+
+    def test_nonblocking_put_exception(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        q.put(0)
+        self.assertRaises(queues.QueueFull, q.put_nowait, 1)
+
+    @gen_test
+    def test_put_with_getters(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        get0 = q.get()
+        get1 = q.get()
+        yield q.put(0)
+        self.assertEqual(0, (yield get0))
+        yield q.put(1)
+        self.assertEqual(1, (yield get1))
+
+    @gen_test
+    def test_nonblocking_put_with_getters(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        get0 = q.get()
+        get1 = q.get()
+        q.put_nowait(0)
+        # put_nowait does *not* immediately unblock getters.
+        yield gen.moment
+        self.assertEqual(0, (yield get0))
+        q.put_nowait(1)
+        yield gen.moment
+        self.assertEqual(1, (yield get1))
+
+    @gen_test
+    def test_blocking_put_wait(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        q.put_nowait(0)
+
+        def get_and_discard():
+            q.get()
+
+        self.io_loop.call_later(0.01, get_and_discard)
+        self.io_loop.call_later(0.02, get_and_discard)
+        futures = [q.put(0), q.put(1)]
+        self.assertFalse(any(f.done() for f in futures))
+        yield futures
+
+    @gen_test
+    def test_put_timeout(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        q.put_nowait(0)  # Now it's full.
+        put_timeout = q.put(1, timeout=timedelta(seconds=0.01))
+        put = q.put(2)
+        with self.assertRaises(TimeoutError):
+            yield put_timeout
+
+        self.assertEqual(0, q.get_nowait())
+        # 1 was never put in the queue.
+        self.assertEqual(2, (yield q.get()))
+
+        # Final get() unblocked this putter.
+        yield put
+
+    @gen_test
+    def test_put_timeout_preempted(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        q.put_nowait(0)
+        put = q.put(1, timeout=timedelta(seconds=0.01))
+        q.get()
+        yield gen.sleep(0.02)
+        yield put  # No TimeoutError.
+
+    @gen_test
+    def test_put_clears_timed_out_putters(self):
+        q = queues.Queue(1)  # type: queues.Queue[int]
+        # First putter succeeds, remainder block.
+        putters = [q.put(i, timedelta(seconds=0.01)) for i in range(10)]
+        put = q.put(10)
+        self.assertEqual(10, len(q._putters))
+        yield gen.sleep(0.02)
+        self.assertEqual(10, len(q._putters))
+        self.assertFalse(put.done())  # Final waiter is still active.
+        q.put(11)  # put() clears the waiters.
+        self.assertEqual(2, len(q._putters))
+        for putter in putters[1:]:
+            self.assertRaises(TimeoutError, putter.result)
+
+    @gen_test
+    def test_put_clears_timed_out_getters(self):
+        q = queues.Queue()  # type: queues.Queue[int]
+        getters = [
+            asyncio.ensure_future(q.get(timedelta(seconds=0.01))) for _ in range(10)
+        ]
+        get = asyncio.ensure_future(q.get())
+        q.get()
+        self.assertEqual(12, len(q._getters))
+        yield gen.sleep(0.02)
+        self.assertEqual(12, len(q._getters))
+        self.assertFalse(get.done())  # Final waiters still active.
+        q.put(0)  # put() clears the waiters.
+        self.assertEqual(1, len(q._getters))
+        self.assertEqual(0, (yield get))
+        for getter in getters:
+            self.assertRaises(TimeoutError, getter.result)
+
+    @gen_test
+    def test_float_maxsize(self):
+        # If a float is passed for maxsize, a reasonable limit should
+        # be enforced, instead of being treated as unlimited.
+        # It happens to be rounded up.
+        # http://bugs.python.org/issue21723
+        q = queues.Queue(maxsize=1.3)  # type: ignore
+        self.assertTrue(q.empty())
+        self.assertFalse(q.full())
+        q.put_nowait(0)
+        q.put_nowait(1)
+        self.assertFalse(q.empty())
+        self.assertTrue(q.full())
+        self.assertRaises(queues.QueueFull, q.put_nowait, 2)
+        self.assertEqual(0, q.get_nowait())
+        self.assertFalse(q.empty())
+        self.assertFalse(q.full())
+
+        yield q.put(2)
+        put = q.put(3)
+        self.assertFalse(put.done())
+        self.assertEqual(1, (yield q.get()))
+        yield put
+        self.assertTrue(q.full())
+
+
+class QueueJoinTest(AsyncTestCase):
+    queue_class = queues.Queue
+
+    def test_task_done_underflow(self):
+        q = self.queue_class()  # type: queues.Queue
+        self.assertRaises(ValueError, q.task_done)
+
+    @gen_test
+    def test_task_done(self):
+        q = self.queue_class()  # type: queues.Queue
+        for i in range(100):
+            q.put_nowait(i)
+
+        self.accumulator = 0
+
+        @gen.coroutine
+        def worker():
+            while True:
+                item = yield q.get()
+                self.accumulator += item
+                q.task_done()
+                yield gen.sleep(random() * 0.01)
+
+        # Two coroutines share work.
+        worker()
+        worker()
+        yield q.join()
+        self.assertEqual(sum(range(100)), self.accumulator)
+
+    @gen_test
+    def test_task_done_delay(self):
+        # Verify it is task_done(), not get(), that unblocks join().
+        q = self.queue_class()  # type: queues.Queue
+        q.put_nowait(0)
+        join = asyncio.ensure_future(q.join())
+        self.assertFalse(join.done())
+        yield q.get()
+        self.assertFalse(join.done())
+        yield gen.moment
+        self.assertFalse(join.done())
+        q.task_done()
+        self.assertTrue(join.done())
+
+    @gen_test
+    def test_join_empty_queue(self):
+        q = self.queue_class()  # type: queues.Queue
+        yield q.join()
+        yield q.join()
+
+    @gen_test
+    def test_join_timeout(self):
+        q = self.queue_class()  # type: queues.Queue
+        q.put(0)
+        with self.assertRaises(TimeoutError):
+            yield q.join(timeout=timedelta(seconds=0.01))
+
+
+class PriorityQueueJoinTest(QueueJoinTest):
+    queue_class = queues.PriorityQueue
+
+    @gen_test
+    def test_order(self):
+        q = self.queue_class(maxsize=2)
+        q.put_nowait((1, "a"))
+        q.put_nowait((0, "b"))
+        self.assertTrue(q.full())
+        q.put((3, "c"))
+        q.put((2, "d"))
+        self.assertEqual((0, "b"), q.get_nowait())
+        self.assertEqual((1, "a"), (yield q.get()))
+        self.assertEqual((2, "d"), q.get_nowait())
+        self.assertEqual((3, "c"), (yield q.get()))
+        self.assertTrue(q.empty())
+
+
+class LifoQueueJoinTest(QueueJoinTest):
+    queue_class = queues.LifoQueue
+
+    @gen_test
+    def test_order(self):
+        q = self.queue_class(maxsize=2)
+        q.put_nowait(1)
+        q.put_nowait(0)
+        self.assertTrue(q.full())
+        q.put(3)
+        q.put(2)
+        self.assertEqual(3, q.get_nowait())
+        self.assertEqual(2, (yield q.get()))
+        self.assertEqual(0, q.get_nowait())
+        self.assertEqual(1, (yield q.get()))
+        self.assertTrue(q.empty())
+
+
+class ProducerConsumerTest(AsyncTestCase):
+    @gen_test
+    def test_producer_consumer(self):
+        q = queues.Queue(maxsize=3)  # type: queues.Queue[int]
+        history = []
+
+        # We don't yield between get() and task_done(), so get() must wait for
+        # the next tick. Otherwise we'd immediately call task_done and unblock
+        # join() before q.put() resumes, and we'd only process the first four
+        # items.
+        @gen.coroutine
+        def consumer():
+            while True:
+                history.append((yield q.get()))
+                q.task_done()
+
+        @gen.coroutine
+        def producer():
+            for item in range(10):
+                yield q.put(item)
+
+        consumer()
+        yield producer()
+        yield q.join()
+        self.assertEqual(list(range(10)), history)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/resolve_test_helper.py b/venv/lib/python3.9/site-packages/tornado/test/resolve_test_helper.py
new file mode 100644
index 00000000..b720a411
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/resolve_test_helper.py
@@ -0,0 +1,10 @@
+from tornado.ioloop import IOLoop
+from tornado.netutil import ThreadedResolver
+
+# When this module is imported, it runs getaddrinfo on a thread. Since
+# the hostname is unicode, getaddrinfo attempts to import encodings.idna
+# but blocks on the import lock. Verify that ThreadedResolver avoids
+# this deadlock.
+
+resolver = ThreadedResolver()
+IOLoop.current().run_sync(lambda: resolver.resolve("localhost", 80))
diff --git a/venv/lib/python3.9/site-packages/tornado/test/routing_test.py b/venv/lib/python3.9/site-packages/tornado/test/routing_test.py
new file mode 100644
index 00000000..6e02697e
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/routing_test.py
@@ -0,0 +1,276 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from tornado.httputil import (
+    HTTPHeaders,
+    HTTPMessageDelegate,
+    HTTPServerConnectionDelegate,
+    ResponseStartLine,
+)
+from tornado.routing import (
+    HostMatches,
+    PathMatches,
+    ReversibleRouter,
+    Router,
+    Rule,
+    RuleRouter,
+)
+from tornado.testing import AsyncHTTPTestCase
+from tornado.web import Application, HTTPError, RequestHandler
+from tornado.wsgi import WSGIContainer
+
+import typing  # noqa: F401
+
+
+class BasicRouter(Router):
+    def find_handler(self, request, **kwargs):
+        class MessageDelegate(HTTPMessageDelegate):
+            def __init__(self, connection):
+                self.connection = connection
+
+            def finish(self):
+                self.connection.write_headers(
+                    ResponseStartLine("HTTP/1.1", 200, "OK"),
+                    HTTPHeaders({"Content-Length": "2"}),
+                    b"OK",
+                )
+                self.connection.finish()
+
+        return MessageDelegate(request.connection)
+
+
+class BasicRouterTestCase(AsyncHTTPTestCase):
+    def get_app(self):
+        return BasicRouter()
+
+    def test_basic_router(self):
+        response = self.fetch("/any_request")
+        self.assertEqual(response.body, b"OK")
+
+
+resources = {}  # type: typing.Dict[str, bytes]
+
+
+class GetResource(RequestHandler):
+    def get(self, path):
+        if path not in resources:
+            raise HTTPError(404)
+
+        self.finish(resources[path])
+
+
+class PostResource(RequestHandler):
+    def post(self, path):
+        resources[path] = self.request.body
+
+
+class HTTPMethodRouter(Router):
+    def __init__(self, app):
+        self.app = app
+
+    def find_handler(self, request, **kwargs):
+        handler = GetResource if request.method == "GET" else PostResource
+        return self.app.get_handler_delegate(request, handler, path_args=[request.path])
+
+
+class HTTPMethodRouterTestCase(AsyncHTTPTestCase):
+    def get_app(self):
+        return HTTPMethodRouter(Application())
+
+    def test_http_method_router(self):
+        response = self.fetch("/post_resource", method="POST", body="data")
+        self.assertEqual(response.code, 200)
+
+        response = self.fetch("/get_resource")
+        self.assertEqual(response.code, 404)
+
+        response = self.fetch("/post_resource")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.body, b"data")
+
+
+def _get_named_handler(handler_name):
+    class Handler(RequestHandler):
+        def get(self, *args, **kwargs):
+            if self.application.settings.get("app_name") is not None:
+                self.write(self.application.settings["app_name"] + ": ")
+
+            self.finish(handler_name + ": " + self.reverse_url(handler_name))
+
+    return Handler
+
+
+FirstHandler = _get_named_handler("first_handler")
+SecondHandler = _get_named_handler("second_handler")
+
+
+class CustomRouter(ReversibleRouter):
+    def __init__(self):
+        super().__init__()
+        self.routes = {}  # type: typing.Dict[str, typing.Any]
+
+    def add_routes(self, routes):
+        self.routes.update(routes)
+
+    def find_handler(self, request, **kwargs):
+        if request.path in self.routes:
+            app, handler = self.routes[request.path]
+            return app.get_handler_delegate(request, handler)
+
+    def reverse_url(self, name, *args):
+        handler_path = "/" + name
+        return handler_path if handler_path in self.routes else None
+
+
+class CustomRouterTestCase(AsyncHTTPTestCase):
+    def get_app(self):
+        router = CustomRouter()
+
+        class CustomApplication(Application):
+            def reverse_url(self, name, *args):
+                return router.reverse_url(name, *args)
+
+        app1 = CustomApplication(app_name="app1")
+        app2 = CustomApplication(app_name="app2")
+
+        router.add_routes(
+            {
+                "/first_handler": (app1, FirstHandler),
+                "/second_handler": (app2, SecondHandler),
+                "/first_handler_second_app": (app2, FirstHandler),
+            }
+        )
+
+        return router
+
+    def test_custom_router(self):
+        response = self.fetch("/first_handler")
+        self.assertEqual(response.body, b"app1: first_handler: /first_handler")
+        response = self.fetch("/second_handler")
+        self.assertEqual(response.body, b"app2: second_handler: /second_handler")
+        response = self.fetch("/first_handler_second_app")
+        self.assertEqual(response.body, b"app2: first_handler: /first_handler")
+
+
+class ConnectionDelegate(HTTPServerConnectionDelegate):
+    def start_request(self, server_conn, request_conn):
+        class MessageDelegate(HTTPMessageDelegate):
+            def __init__(self, connection):
+                self.connection = connection
+
+            def finish(self):
+                response_body = b"OK"
+                self.connection.write_headers(
+                    ResponseStartLine("HTTP/1.1", 200, "OK"),
+                    HTTPHeaders({"Content-Length": str(len(response_body))}),
+                )
+                self.connection.write(response_body)
+                self.connection.finish()
+
+        return MessageDelegate(request_conn)
+
+
+class RuleRouterTest(AsyncHTTPTestCase):
+    def get_app(self):
+        app = Application()
+
+        def request_callable(request):
+            request.connection.write_headers(
+                ResponseStartLine("HTTP/1.1", 200, "OK"),
+                HTTPHeaders({"Content-Length": "2"}),
+            )
+            request.connection.write(b"OK")
+            request.connection.finish()
+
+        router = CustomRouter()
+        router.add_routes(
+            {"/nested_handler": (app, _get_named_handler("nested_handler"))}
+        )
+
+        app.add_handlers(
+            ".*",
+            [
+                (
+                    HostMatches("www.example.com"),
+                    [
+                        (
+                            PathMatches("/first_handler"),
+                            "tornado.test.routing_test.SecondHandler",
+                            {},
+                            "second_handler",
+                        )
+                    ],
+                ),
+                Rule(PathMatches("/.*handler"), router),
+                Rule(PathMatches("/first_handler"), FirstHandler, name="first_handler"),
+                Rule(PathMatches("/request_callable"), request_callable),
+                ("/connection_delegate", ConnectionDelegate()),
+            ],
+        )
+
+        return app
+
+    def test_rule_based_router(self):
+        response = self.fetch("/first_handler")
+        self.assertEqual(response.body, b"first_handler: /first_handler")
+
+        response = self.fetch("/first_handler", headers={"Host": "www.example.com"})
+        self.assertEqual(response.body, b"second_handler: /first_handler")
+
+        response = self.fetch("/nested_handler")
+        self.assertEqual(response.body, b"nested_handler: /nested_handler")
+
+        response = self.fetch("/nested_not_found_handler")
+        self.assertEqual(response.code, 404)
+
+        response = self.fetch("/connection_delegate")
+        self.assertEqual(response.body, b"OK")
+
+        response = self.fetch("/request_callable")
+        self.assertEqual(response.body, b"OK")
+
+        response = self.fetch("/404")
+        self.assertEqual(response.code, 404)
+
+
+class WSGIContainerTestCase(AsyncHTTPTestCase):
+    def get_app(self):
+        wsgi_app = WSGIContainer(self.wsgi_app)
+
+        class Handler(RequestHandler):
+            def get(self, *args, **kwargs):
+                self.finish(self.reverse_url("tornado"))
+
+        return RuleRouter(
+            [
+                (
+                    PathMatches("/tornado.*"),
+                    Application([(r"/tornado/test", Handler, {}, "tornado")]),
+                ),
+                (PathMatches("/wsgi"), wsgi_app),
+            ]
+        )
+
+    def wsgi_app(self, environ, start_response):
+        start_response("200 OK", [])
+        return [b"WSGI"]
+
+    def test_wsgi_container(self):
+        response = self.fetch("/tornado/test")
+        self.assertEqual(response.body, b"/tornado/test")
+
+        response = self.fetch("/wsgi")
+        self.assertEqual(response.body, b"WSGI")
+
+    def test_delegate_not_found(self):
+        response = self.fetch("/404")
+        self.assertEqual(response.code, 404)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/runtests.py b/venv/lib/python3.9/site-packages/tornado/test/runtests.py
new file mode 100644
index 00000000..6075b1e2
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/runtests.py
@@ -0,0 +1,241 @@
+from functools import reduce
+import gc
+import io
+import locale  # system locale module, not tornado.locale
+import logging
+import operator
+import textwrap
+import sys
+import unittest
+import warnings
+
+from tornado.httpclient import AsyncHTTPClient
+from tornado.httpserver import HTTPServer
+from tornado.netutil import Resolver
+from tornado.options import define, add_parse_callback, options
+
+
+TEST_MODULES = [
+    "tornado.httputil.doctests",
+    "tornado.iostream.doctests",
+    "tornado.util.doctests",
+    "tornado.test.asyncio_test",
+    "tornado.test.auth_test",
+    "tornado.test.autoreload_test",
+    "tornado.test.concurrent_test",
+    "tornado.test.curl_httpclient_test",
+    "tornado.test.escape_test",
+    "tornado.test.gen_test",
+    "tornado.test.http1connection_test",
+    "tornado.test.httpclient_test",
+    "tornado.test.httpserver_test",
+    "tornado.test.httputil_test",
+    "tornado.test.import_test",
+    "tornado.test.ioloop_test",
+    "tornado.test.iostream_test",
+    "tornado.test.locale_test",
+    "tornado.test.locks_test",
+    "tornado.test.netutil_test",
+    "tornado.test.log_test",
+    "tornado.test.options_test",
+    "tornado.test.process_test",
+    "tornado.test.queues_test",
+    "tornado.test.routing_test",
+    "tornado.test.simple_httpclient_test",
+    "tornado.test.tcpclient_test",
+    "tornado.test.tcpserver_test",
+    "tornado.test.template_test",
+    "tornado.test.testing_test",
+    "tornado.test.twisted_test",
+    "tornado.test.util_test",
+    "tornado.test.web_test",
+    "tornado.test.websocket_test",
+    "tornado.test.wsgi_test",
+]
+
+
+def all():
+    return unittest.defaultTestLoader.loadTestsFromNames(TEST_MODULES)
+
+
+def test_runner_factory(stderr):
+    class TornadoTextTestRunner(unittest.TextTestRunner):
+        def __init__(self, *args, **kwargs):
+            kwargs["stream"] = stderr
+            super().__init__(*args, **kwargs)
+
+        def run(self, test):
+            result = super().run(test)
+            if result.skipped:
+                skip_reasons = set(reason for (test, reason) in result.skipped)
+                self.stream.write(  # type: ignore
+                    textwrap.fill(
+                        "Some tests were skipped because: %s"
+                        % ", ".join(sorted(skip_reasons))
+                    )
+                )
+                self.stream.write("\n")  # type: ignore
+            return result
+
+    return TornadoTextTestRunner
+
+
+class LogCounter(logging.Filter):
+    """Counts the number of WARNING or higher log records."""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.info_count = self.warning_count = self.error_count = 0
+
+    def filter(self, record):
+        if record.levelno >= logging.ERROR:
+            self.error_count += 1
+        elif record.levelno >= logging.WARNING:
+            self.warning_count += 1
+        elif record.levelno >= logging.INFO:
+            self.info_count += 1
+        return True
+
+
+class CountingStderr(io.IOBase):
+    def __init__(self, real):
+        self.real = real
+        self.byte_count = 0
+
+    def write(self, data):
+        self.byte_count += len(data)
+        return self.real.write(data)
+
+    def flush(self):
+        return self.real.flush()
+
+
+def main():
+    # Be strict about most warnings (This is set in our test running
+    # scripts to catch import-time warnings, but set it again here to
+    # be sure). This also turns on warnings that are ignored by
+    # default, including DeprecationWarnings and python 3.2's
+    # ResourceWarnings.
+    warnings.filterwarnings("error")
+    # setuptools sometimes gives ImportWarnings about things that are on
+    # sys.path even if they're not being used.
+    warnings.filterwarnings("ignore", category=ImportWarning)
+    # Tornado generally shouldn't use anything deprecated, but some of
+    # our dependencies do (last match wins).
+    warnings.filterwarnings("ignore", category=DeprecationWarning)
+    warnings.filterwarnings("error", category=DeprecationWarning, module=r"tornado\..*")
+    warnings.filterwarnings("ignore", category=PendingDeprecationWarning)
+    warnings.filterwarnings(
+        "error", category=PendingDeprecationWarning, module=r"tornado\..*"
+    )
+    # The unittest module is aggressive about deprecating redundant methods,
+    # leaving some without non-deprecated spellings that work on both
+    # 2.7 and 3.2
+    warnings.filterwarnings(
+        "ignore", category=DeprecationWarning, message="Please use assert.* instead"
+    )
+    warnings.filterwarnings(
+        "ignore",
+        category=PendingDeprecationWarning,
+        message="Please use assert.* instead",
+    )
+    # Twisted 15.0.0 triggers some warnings on py3 with -bb.
+    warnings.filterwarnings("ignore", category=BytesWarning, module=r"twisted\..*")
+    if (3,) < sys.version_info < (3, 6):
+        # Prior to 3.6, async ResourceWarnings were rather noisy
+        # and even
+        # `python3.4 -W error -c 'import asyncio; asyncio.get_event_loop()'`
+        # would generate a warning.
+        warnings.filterwarnings(
+            "ignore", category=ResourceWarning, module=r"asyncio\..*"
+        )
+    # This deprecation warning is introduced in Python 3.8 and is
+    # triggered by pycurl. Unforunately, because it is raised in the C
+    # layer it can't be filtered by module and we must match the
+    # message text instead (Tornado's C module uses PY_SSIZE_T_CLEAN
+    # so it's not at risk of running into this issue).
+    warnings.filterwarnings(
+        "ignore",
+        category=DeprecationWarning,
+        message="PY_SSIZE_T_CLEAN will be required",
+    )
+
+    logging.getLogger("tornado.access").setLevel(logging.CRITICAL)
+
+    define(
+        "httpclient",
+        type=str,
+        default=None,
+        callback=lambda s: AsyncHTTPClient.configure(
+            s, defaults=dict(allow_ipv6=False)
+        ),
+    )
+    define("httpserver", type=str, default=None, callback=HTTPServer.configure)
+    define("resolver", type=str, default=None, callback=Resolver.configure)
+    define(
+        "debug_gc",
+        type=str,
+        multiple=True,
+        help="A comma-separated list of gc module debug constants, "
+        "e.g. DEBUG_STATS or DEBUG_COLLECTABLE,DEBUG_OBJECTS",
+        callback=lambda values: gc.set_debug(
+            reduce(operator.or_, (getattr(gc, v) for v in values))
+        ),
+    )
+    define(
+        "fail-if-logs",
+        default=True,
+        help="If true, fail the tests if any log output is produced (unless captured by ExpectLog)",
+    )
+
+    def set_locale(x):
+        locale.setlocale(locale.LC_ALL, x)
+
+    define("locale", type=str, default=None, callback=set_locale)
+
+    log_counter = LogCounter()
+    add_parse_callback(lambda: logging.getLogger().handlers[0].addFilter(log_counter))
+
+    # Certain errors (especially "unclosed resource" errors raised in
+    # destructors) go directly to stderr instead of logging. Count
+    # anything written by anything but the test runner as an error.
+    orig_stderr = sys.stderr
+    counting_stderr = CountingStderr(orig_stderr)
+    sys.stderr = counting_stderr  # type: ignore
+
+    import tornado.testing
+
+    kwargs = {}
+
+    # HACK:  unittest.main will make its own changes to the warning
+    # configuration, which may conflict with the settings above
+    # or command-line flags like -bb.  Passing warnings=False
+    # suppresses this behavior, although this looks like an implementation
+    # detail.  http://bugs.python.org/issue15626
+    kwargs["warnings"] = False
+
+    kwargs["testRunner"] = test_runner_factory(orig_stderr)
+    try:
+        tornado.testing.main(**kwargs)
+    finally:
+        # The tests should run clean; consider it a failure if they
+        # logged anything at info level or above.
+        if (
+            log_counter.info_count > 0
+            or log_counter.warning_count > 0
+            or log_counter.error_count > 0
+            or counting_stderr.byte_count > 0
+        ):
+            logging.error(
+                "logged %d infos, %d warnings, %d errors, and %d bytes to stderr",
+                log_counter.info_count,
+                log_counter.warning_count,
+                log_counter.error_count,
+                counting_stderr.byte_count,
+            )
+            if options.fail_if_logs:
+                sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/simple_httpclient_test.py b/venv/lib/python3.9/site-packages/tornado/test/simple_httpclient_test.py
new file mode 100644
index 00000000..62bd4830
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/simple_httpclient_test.py
@@ -0,0 +1,837 @@
+import collections
+from contextlib import closing
+import errno
+import logging
+import os
+import re
+import socket
+import ssl
+import sys
+import typing  # noqa: F401
+
+from tornado.escape import to_unicode, utf8
+from tornado import gen, version
+from tornado.httpclient import AsyncHTTPClient
+from tornado.httputil import HTTPHeaders, ResponseStartLine
+from tornado.ioloop import IOLoop
+from tornado.iostream import UnsatisfiableReadError
+from tornado.locks import Event
+from tornado.log import gen_log
+from tornado.netutil import Resolver, bind_sockets
+from tornado.simple_httpclient import (
+    SimpleAsyncHTTPClient,
+    HTTPStreamClosedError,
+    HTTPTimeoutError,
+)
+from tornado.test.httpclient_test import (
+    ChunkHandler,
+    CountdownHandler,
+    HelloWorldHandler,
+    RedirectHandler,
+    UserAgentHandler,
+)
+from tornado.test import httpclient_test
+from tornado.testing import (
+    AsyncHTTPTestCase,
+    AsyncHTTPSTestCase,
+    AsyncTestCase,
+    ExpectLog,
+    gen_test,
+)
+from tornado.test.util import skipOnTravis, skipIfNoIPv6, refusing_port
+from tornado.web import RequestHandler, Application, url, stream_request_body
+
+
+class SimpleHTTPClientCommonTestCase(httpclient_test.HTTPClientCommonTestCase):
+    def get_http_client(self):
+        client = SimpleAsyncHTTPClient(force_instance=True)
+        self.assertTrue(isinstance(client, SimpleAsyncHTTPClient))
+        return client
+
+
+class TriggerHandler(RequestHandler):
+    def initialize(self, queue, wake_callback):
+        self.queue = queue
+        self.wake_callback = wake_callback
+
+    @gen.coroutine
+    def get(self):
+        logging.debug("queuing trigger")
+        event = Event()
+        self.queue.append(event.set)
+        if self.get_argument("wake", "true") == "true":
+            self.wake_callback()
+        yield event.wait()
+
+
+class ContentLengthHandler(RequestHandler):
+    def get(self):
+        self.stream = self.detach()
+        IOLoop.current().spawn_callback(self.write_response)
+
+    @gen.coroutine
+    def write_response(self):
+        yield self.stream.write(
+            utf8(
+                "HTTP/1.0 200 OK\r\nContent-Length: %s\r\n\r\nok"
+                % self.get_argument("value")
+            )
+        )
+        self.stream.close()
+
+
+class HeadHandler(RequestHandler):
+    def head(self):
+        self.set_header("Content-Length", "7")
+
+
+class OptionsHandler(RequestHandler):
+    def options(self):
+        self.set_header("Access-Control-Allow-Origin", "*")
+        self.write("ok")
+
+
+class NoContentHandler(RequestHandler):
+    def get(self):
+        self.set_status(204)
+        self.finish()
+
+
+class SeeOtherPostHandler(RequestHandler):
+    def post(self):
+        redirect_code = int(self.request.body)
+        assert redirect_code in (302, 303), "unexpected body %r" % self.request.body
+        self.set_header("Location", "/see_other_get")
+        self.set_status(redirect_code)
+
+
+class SeeOtherGetHandler(RequestHandler):
+    def get(self):
+        if self.request.body:
+            raise Exception("unexpected body %r" % self.request.body)
+        self.write("ok")
+
+
+class HostEchoHandler(RequestHandler):
+    def get(self):
+        self.write(self.request.headers["Host"])
+
+
+class NoContentLengthHandler(RequestHandler):
+    def get(self):
+        if self.request.version.startswith("HTTP/1"):
+            # Emulate the old HTTP/1.0 behavior of returning a body with no
+            # content-length.  Tornado handles content-length at the framework
+            # level so we have to go around it.
+            stream = self.detach()
+            stream.write(b"HTTP/1.0 200 OK\r\n\r\n" b"hello")
+            stream.close()
+        else:
+            self.finish("HTTP/1 required")
+
+
+class EchoPostHandler(RequestHandler):
+    def post(self):
+        self.write(self.request.body)
+
+
+@stream_request_body
+class RespondInPrepareHandler(RequestHandler):
+    def prepare(self):
+        self.set_status(403)
+        self.finish("forbidden")
+
+
+class SimpleHTTPClientTestMixin(object):
+    def create_client(self, **kwargs):
+        raise NotImplementedError()
+
+    def get_app(self: typing.Any):
+        # callable objects to finish pending /trigger requests
+        self.triggers = (
+            collections.deque()
+        )  # type: typing.Deque[typing.Callable[[], None]]
+        return Application(
+            [
+                url(
+                    "/trigger",
+                    TriggerHandler,
+                    dict(queue=self.triggers, wake_callback=self.stop),
+                ),
+                url("/chunk", ChunkHandler),
+                url("/countdown/([0-9]+)", CountdownHandler, name="countdown"),
+                url("/hello", HelloWorldHandler),
+                url("/content_length", ContentLengthHandler),
+                url("/head", HeadHandler),
+                url("/options", OptionsHandler),
+                url("/no_content", NoContentHandler),
+                url("/see_other_post", SeeOtherPostHandler),
+                url("/see_other_get", SeeOtherGetHandler),
+                url("/host_echo", HostEchoHandler),
+                url("/no_content_length", NoContentLengthHandler),
+                url("/echo_post", EchoPostHandler),
+                url("/respond_in_prepare", RespondInPrepareHandler),
+                url("/redirect", RedirectHandler),
+                url("/user_agent", UserAgentHandler),
+            ],
+            gzip=True,
+        )
+
+    def test_singleton(self: typing.Any):
+        # Class "constructor" reuses objects on the same IOLoop
+        self.assertTrue(SimpleAsyncHTTPClient() is SimpleAsyncHTTPClient())
+        # unless force_instance is used
+        self.assertTrue(
+            SimpleAsyncHTTPClient() is not SimpleAsyncHTTPClient(force_instance=True)
+        )
+        # different IOLoops use different objects
+        with closing(IOLoop()) as io_loop2:
+
+            async def make_client():
+                await gen.sleep(0)
+                return SimpleAsyncHTTPClient()
+
+            client1 = self.io_loop.run_sync(make_client)
+            client2 = io_loop2.run_sync(make_client)
+            self.assertTrue(client1 is not client2)
+
+    def test_connection_limit(self: typing.Any):
+        with closing(self.create_client(max_clients=2)) as client:
+            self.assertEqual(client.max_clients, 2)
+            seen = []
+            # Send 4 requests.  Two can be sent immediately, while the others
+            # will be queued
+            for i in range(4):
+
+                def cb(fut, i=i):
+                    seen.append(i)
+                    self.stop()
+
+                client.fetch(self.get_url("/trigger")).add_done_callback(cb)
+            self.wait(condition=lambda: len(self.triggers) == 2)
+            self.assertEqual(len(client.queue), 2)
+
+            # Finish the first two requests and let the next two through
+            self.triggers.popleft()()
+            self.triggers.popleft()()
+            self.wait(condition=lambda: (len(self.triggers) == 2 and len(seen) == 2))
+            self.assertEqual(set(seen), set([0, 1]))
+            self.assertEqual(len(client.queue), 0)
+
+            # Finish all the pending requests
+            self.triggers.popleft()()
+            self.triggers.popleft()()
+            self.wait(condition=lambda: len(seen) == 4)
+            self.assertEqual(set(seen), set([0, 1, 2, 3]))
+            self.assertEqual(len(self.triggers), 0)
+
+    @gen_test
+    def test_redirect_connection_limit(self: typing.Any):
+        # following redirects should not consume additional connections
+        with closing(self.create_client(max_clients=1)) as client:
+            response = yield client.fetch(self.get_url("/countdown/3"), max_redirects=3)
+            response.rethrow()
+
+    def test_max_redirects(self: typing.Any):
+        response = self.fetch("/countdown/5", max_redirects=3)
+        self.assertEqual(302, response.code)
+        # We requested 5, followed three redirects for 4, 3, 2, then the last
+        # unfollowed redirect is to 1.
+        self.assertTrue(response.request.url.endswith("/countdown/5"))
+        self.assertTrue(response.effective_url.endswith("/countdown/2"))
+        self.assertTrue(response.headers["Location"].endswith("/countdown/1"))
+
+    def test_header_reuse(self: typing.Any):
+        # Apps may reuse a headers object if they are only passing in constant
+        # headers like user-agent.  The header object should not be modified.
+        headers = HTTPHeaders({"User-Agent": "Foo"})
+        self.fetch("/hello", headers=headers)
+        self.assertEqual(list(headers.get_all()), [("User-Agent", "Foo")])
+
+    def test_default_user_agent(self: typing.Any):
+        response = self.fetch("/user_agent", method="GET")
+        self.assertEqual(200, response.code)
+        self.assertEqual(response.body.decode(), "Tornado/{}".format(version))
+
+    def test_see_other_redirect(self: typing.Any):
+        for code in (302, 303):
+            response = self.fetch("/see_other_post", method="POST", body="%d" % code)
+            self.assertEqual(200, response.code)
+            self.assertTrue(response.request.url.endswith("/see_other_post"))
+            self.assertTrue(response.effective_url.endswith("/see_other_get"))
+            # request is the original request, is a POST still
+            self.assertEqual("POST", response.request.method)
+
+    @skipOnTravis
+    @gen_test
+    def test_connect_timeout(self: typing.Any):
+        timeout = 0.1
+
+        cleanup_event = Event()
+        test = self
+
+        class TimeoutResolver(Resolver):
+            async def resolve(self, *args, **kwargs):
+                await cleanup_event.wait()
+                # Return something valid so the test doesn't raise during shutdown.
+                return [(socket.AF_INET, ("127.0.0.1", test.get_http_port()))]
+
+        with closing(self.create_client(resolver=TimeoutResolver())) as client:
+            with self.assertRaises(HTTPTimeoutError):
+                yield client.fetch(
+                    self.get_url("/hello"),
+                    connect_timeout=timeout,
+                    request_timeout=3600,
+                    raise_error=True,
+                )
+
+        # Let the hanging coroutine clean up after itself. We need to
+        # wait more than a single IOLoop iteration for the SSL case,
+        # which logs errors on unexpected EOF.
+        cleanup_event.set()
+        yield gen.sleep(0.2)
+
+    @skipOnTravis
+    def test_request_timeout(self: typing.Any):
+        timeout = 0.1
+        if os.name == "nt":
+            timeout = 0.5
+
+        with self.assertRaises(HTTPTimeoutError):
+            self.fetch("/trigger?wake=false", request_timeout=timeout, raise_error=True)
+        # trigger the hanging request to let it clean up after itself
+        self.triggers.popleft()()
+        self.io_loop.run_sync(lambda: gen.sleep(0))
+
+    @skipIfNoIPv6
+    def test_ipv6(self: typing.Any):
+        [sock] = bind_sockets(0, "::1", family=socket.AF_INET6)
+        port = sock.getsockname()[1]
+        self.http_server.add_socket(sock)
+        url = "%s://[::1]:%d/hello" % (self.get_protocol(), port)
+
+        # ipv6 is currently enabled by default but can be disabled
+        with self.assertRaises(Exception):
+            self.fetch(url, allow_ipv6=False, raise_error=True)
+
+        response = self.fetch(url)
+        self.assertEqual(response.body, b"Hello world!")
+
+    def test_multiple_content_length_accepted(self: typing.Any):
+        response = self.fetch("/content_length?value=2,2")
+        self.assertEqual(response.body, b"ok")
+        response = self.fetch("/content_length?value=2,%202,2")
+        self.assertEqual(response.body, b"ok")
+
+        with ExpectLog(
+            gen_log, ".*Multiple unequal Content-Lengths", level=logging.INFO
+        ):
+            with self.assertRaises(HTTPStreamClosedError):
+                self.fetch("/content_length?value=2,4", raise_error=True)
+            with self.assertRaises(HTTPStreamClosedError):
+                self.fetch("/content_length?value=2,%202,3", raise_error=True)
+
+    def test_head_request(self: typing.Any):
+        response = self.fetch("/head", method="HEAD")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.headers["content-length"], "7")
+        self.assertFalse(response.body)
+
+    def test_options_request(self: typing.Any):
+        response = self.fetch("/options", method="OPTIONS")
+        self.assertEqual(response.code, 200)
+        self.assertEqual(response.headers["content-length"], "2")
+        self.assertEqual(response.headers["access-control-allow-origin"], "*")
+        self.assertEqual(response.body, b"ok")
+
+    def test_no_content(self: typing.Any):
+        response = self.fetch("/no_content")
+        self.assertEqual(response.code, 204)
+        # 204 status shouldn't have a content-length
+        #
+        # Tests with a content-length header are included below
+        # in HTTP204NoContentTestCase.
+        self.assertNotIn("Content-Length", response.headers)
+
+    def test_host_header(self: typing.Any):
+        host_re = re.compile(b"^127.0.0.1:[0-9]+$")
+        response = self.fetch("/host_echo")
+        self.assertTrue(host_re.match(response.body))
+
+        url = self.get_url("/host_echo").replace("http://", "http://me:secret@")
+        response = self.fetch(url)
+        self.assertTrue(host_re.match(response.body), response.body)
+
+    def test_connection_refused(self: typing.Any):
+        cleanup_func, port = refusing_port()
+        self.addCleanup(cleanup_func)
+        with ExpectLog(gen_log, ".*", required=False):
+            with self.assertRaises(socket.error) as cm:
+                self.fetch("http://127.0.0.1:%d/" % port, raise_error=True)
+
+        if sys.platform != "cygwin":
+            # cygwin returns EPERM instead of ECONNREFUSED here
+            contains_errno = str(errno.ECONNREFUSED) in str(cm.exception)
+            if not contains_errno and hasattr(errno, "WSAECONNREFUSED"):
+                contains_errno = str(errno.WSAECONNREFUSED) in str(  # type: ignore
+                    cm.exception
+                )
+            self.assertTrue(contains_errno, cm.exception)
+            # This is usually "Connection refused".
+            # On windows, strerror is broken and returns "Unknown error".
+            expected_message = os.strerror(errno.ECONNREFUSED)
+            self.assertTrue(expected_message in str(cm.exception), cm.exception)
+
+    def test_queue_timeout(self: typing.Any):
+        with closing(self.create_client(max_clients=1)) as client:
+            # Wait for the trigger request to block, not complete.
+            fut1 = client.fetch(self.get_url("/trigger"), request_timeout=10)
+            self.wait()
+            with self.assertRaises(HTTPTimeoutError) as cm:
+                self.io_loop.run_sync(
+                    lambda: client.fetch(
+                        self.get_url("/hello"), connect_timeout=0.1, raise_error=True
+                    )
+                )
+
+            self.assertEqual(str(cm.exception), "Timeout in request queue")
+            self.triggers.popleft()()
+            self.io_loop.run_sync(lambda: fut1)
+
+    def test_no_content_length(self: typing.Any):
+        response = self.fetch("/no_content_length")
+        if response.body == b"HTTP/1 required":
+            self.skipTest("requires HTTP/1.x")
+        else:
+            self.assertEqual(b"hello", response.body)
+
+    def sync_body_producer(self, write):
+        write(b"1234")
+        write(b"5678")
+
+    @gen.coroutine
+    def async_body_producer(self, write):
+        yield write(b"1234")
+        yield gen.moment
+        yield write(b"5678")
+
+    def test_sync_body_producer_chunked(self: typing.Any):
+        response = self.fetch(
+            "/echo_post", method="POST", body_producer=self.sync_body_producer
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_sync_body_producer_content_length(self: typing.Any):
+        response = self.fetch(
+            "/echo_post",
+            method="POST",
+            body_producer=self.sync_body_producer,
+            headers={"Content-Length": "8"},
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_async_body_producer_chunked(self: typing.Any):
+        response = self.fetch(
+            "/echo_post", method="POST", body_producer=self.async_body_producer
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_async_body_producer_content_length(self: typing.Any):
+        response = self.fetch(
+            "/echo_post",
+            method="POST",
+            body_producer=self.async_body_producer,
+            headers={"Content-Length": "8"},
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_native_body_producer_chunked(self: typing.Any):
+        async def body_producer(write):
+            await write(b"1234")
+            import asyncio
+
+            await asyncio.sleep(0)
+            await write(b"5678")
+
+        response = self.fetch("/echo_post", method="POST", body_producer=body_producer)
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_native_body_producer_content_length(self: typing.Any):
+        async def body_producer(write):
+            await write(b"1234")
+            import asyncio
+
+            await asyncio.sleep(0)
+            await write(b"5678")
+
+        response = self.fetch(
+            "/echo_post",
+            method="POST",
+            body_producer=body_producer,
+            headers={"Content-Length": "8"},
+        )
+        response.rethrow()
+        self.assertEqual(response.body, b"12345678")
+
+    def test_100_continue(self: typing.Any):
+        response = self.fetch(
+            "/echo_post", method="POST", body=b"1234", expect_100_continue=True
+        )
+        self.assertEqual(response.body, b"1234")
+
+    def test_100_continue_early_response(self: typing.Any):
+        def body_producer(write):
+            raise Exception("should not be called")
+
+        response = self.fetch(
+            "/respond_in_prepare",
+            method="POST",
+            body_producer=body_producer,
+            expect_100_continue=True,
+        )
+        self.assertEqual(response.code, 403)
+
+    def test_streaming_follow_redirects(self: typing.Any):
+        # When following redirects, header and streaming callbacks
+        # should only be called for the final result.
+        # TODO(bdarnell): this test belongs in httpclient_test instead of
+        # simple_httpclient_test, but it fails with the version of libcurl
+        # available on travis-ci. Move it when that has been upgraded
+        # or we have a better framework to skip tests based on curl version.
+        headers = []  # type: typing.List[str]
+        chunk_bytes = []  # type: typing.List[bytes]
+        self.fetch(
+            "/redirect?url=/hello",
+            header_callback=headers.append,
+            streaming_callback=chunk_bytes.append,
+        )
+        chunks = list(map(to_unicode, chunk_bytes))
+        self.assertEqual(chunks, ["Hello world!"])
+        # Make sure we only got one set of headers.
+        num_start_lines = len([h for h in headers if h.startswith("HTTP/")])
+        self.assertEqual(num_start_lines, 1)
+
+
+class SimpleHTTPClientTestCase(SimpleHTTPClientTestMixin, AsyncHTTPTestCase):
+    def setUp(self):
+        super().setUp()
+        self.http_client = self.create_client()
+
+    def create_client(self, **kwargs):
+        return SimpleAsyncHTTPClient(force_instance=True, **kwargs)
+
+
+class SimpleHTTPSClientTestCase(SimpleHTTPClientTestMixin, AsyncHTTPSTestCase):
+    def setUp(self):
+        super().setUp()
+        self.http_client = self.create_client()
+
+    def create_client(self, **kwargs):
+        return SimpleAsyncHTTPClient(
+            force_instance=True, defaults=dict(validate_cert=False), **kwargs
+        )
+
+    def test_ssl_options(self):
+        resp = self.fetch("/hello", ssl_options={"cert_reqs": ssl.CERT_NONE})
+        self.assertEqual(resp.body, b"Hello world!")
+
+    def test_ssl_context(self):
+        ssl_ctx = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
+        ssl_ctx.check_hostname = False
+        ssl_ctx.verify_mode = ssl.CERT_NONE
+        resp = self.fetch("/hello", ssl_options=ssl_ctx)
+        self.assertEqual(resp.body, b"Hello world!")
+
+    def test_ssl_options_handshake_fail(self):
+        with ExpectLog(gen_log, "SSL Error|Uncaught exception", required=False):
+            with self.assertRaises(ssl.SSLError):
+                self.fetch(
+                    "/hello",
+                    ssl_options=dict(cert_reqs=ssl.CERT_REQUIRED),
+                    raise_error=True,
+                )
+
+    def test_ssl_context_handshake_fail(self):
+        with ExpectLog(gen_log, "SSL Error|Uncaught exception"):
+            # CERT_REQUIRED is set by default.
+            ctx = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
+            with self.assertRaises(ssl.SSLError):
+                self.fetch("/hello", ssl_options=ctx, raise_error=True)
+
+    def test_error_logging(self):
+        # No stack traces are logged for SSL errors (in this case,
+        # failure to validate the testing self-signed cert).
+        # The SSLError is exposed through ssl.SSLError.
+        with ExpectLog(gen_log, ".*") as expect_log:
+            with self.assertRaises(ssl.SSLError):
+                self.fetch("/", validate_cert=True, raise_error=True)
+        self.assertFalse(expect_log.logged_stack)
+
+
+class CreateAsyncHTTPClientTestCase(AsyncTestCase):
+    def setUp(self):
+        super().setUp()
+        self.saved = AsyncHTTPClient._save_configuration()
+
+    def tearDown(self):
+        AsyncHTTPClient._restore_configuration(self.saved)
+        super().tearDown()
+
+    def test_max_clients(self):
+        AsyncHTTPClient.configure(SimpleAsyncHTTPClient)
+        with closing(AsyncHTTPClient(force_instance=True)) as client:
+            self.assertEqual(client.max_clients, 10)  # type: ignore
+        with closing(AsyncHTTPClient(max_clients=11, force_instance=True)) as client:
+            self.assertEqual(client.max_clients, 11)  # type: ignore
+
+        # Now configure max_clients statically and try overriding it
+        # with each way max_clients can be passed
+        AsyncHTTPClient.configure(SimpleAsyncHTTPClient, max_clients=12)
+        with closing(AsyncHTTPClient(force_instance=True)) as client:
+            self.assertEqual(client.max_clients, 12)  # type: ignore
+        with closing(AsyncHTTPClient(max_clients=13, force_instance=True)) as client:
+            self.assertEqual(client.max_clients, 13)  # type: ignore
+        with closing(AsyncHTTPClient(max_clients=14, force_instance=True)) as client:
+            self.assertEqual(client.max_clients, 14)  # type: ignore
+
+
+class HTTP100ContinueTestCase(AsyncHTTPTestCase):
+    def respond_100(self, request):
+        self.http1 = request.version.startswith("HTTP/1.")
+        if not self.http1:
+            request.connection.write_headers(
+                ResponseStartLine("", 200, "OK"), HTTPHeaders()
+            )
+            request.connection.finish()
+            return
+        self.request = request
+        fut = self.request.connection.stream.write(b"HTTP/1.1 100 CONTINUE\r\n\r\n")
+        fut.add_done_callback(self.respond_200)
+
+    def respond_200(self, fut):
+        fut.result()
+        fut = self.request.connection.stream.write(
+            b"HTTP/1.1 200 OK\r\nContent-Length: 1\r\n\r\nA"
+        )
+        fut.add_done_callback(lambda f: self.request.connection.stream.close())
+
+    def get_app(self):
+        # Not a full Application, but works as an HTTPServer callback
+        return self.respond_100
+
+    def test_100_continue(self):
+        res = self.fetch("/")
+        if not self.http1:
+            self.skipTest("requires HTTP/1.x")
+        self.assertEqual(res.body, b"A")
+
+
+class HTTP204NoContentTestCase(AsyncHTTPTestCase):
+    def respond_204(self, request):
+        self.http1 = request.version.startswith("HTTP/1.")
+        if not self.http1:
+            # Close the request cleanly in HTTP/2; it will be skipped anyway.
+            request.connection.write_headers(
+                ResponseStartLine("", 200, "OK"), HTTPHeaders()
+            )
+            request.connection.finish()
+            return
+
+        # A 204 response never has a body, even if doesn't have a content-length
+        # (which would otherwise mean read-until-close).  We simulate here a
+        # server that sends no content length and does not close the connection.
+        #
+        # Tests of a 204 response with no Content-Length header are included
+        # in SimpleHTTPClientTestMixin.
+        stream = request.connection.detach()
+        stream.write(b"HTTP/1.1 204 No content\r\n")
+        if request.arguments.get("error", [False])[-1]:
+            stream.write(b"Content-Length: 5\r\n")
+        else:
+            stream.write(b"Content-Length: 0\r\n")
+        stream.write(b"\r\n")
+        stream.close()
+
+    def get_app(self):
+        return self.respond_204
+
+    def test_204_no_content(self):
+        resp = self.fetch("/")
+        if not self.http1:
+            self.skipTest("requires HTTP/1.x")
+        self.assertEqual(resp.code, 204)
+        self.assertEqual(resp.body, b"")
+
+    def test_204_invalid_content_length(self):
+        # 204 status with non-zero content length is malformed
+        with ExpectLog(
+            gen_log, ".*Response with code 204 should not have body", level=logging.INFO
+        ):
+            with self.assertRaises(HTTPStreamClosedError):
+                self.fetch("/?error=1", raise_error=True)
+                if not self.http1:
+                    self.skipTest("requires HTTP/1.x")
+                if self.http_client.configured_class != SimpleAsyncHTTPClient:
+                    self.skipTest("curl client accepts invalid headers")
+
+
+class HostnameMappingTestCase(AsyncHTTPTestCase):
+    def setUp(self):
+        super().setUp()
+        self.http_client = SimpleAsyncHTTPClient(
+            hostname_mapping={
+                "www.example.com": "127.0.0.1",
+                ("foo.example.com", 8000): ("127.0.0.1", self.get_http_port()),
+            }
+        )
+
+    def get_app(self):
+        return Application([url("/hello", HelloWorldHandler)])
+
+    def test_hostname_mapping(self):
+        response = self.fetch("http://www.example.com:%d/hello" % self.get_http_port())
+        response.rethrow()
+        self.assertEqual(response.body, b"Hello world!")
+
+    def test_port_mapping(self):
+        response = self.fetch("http://foo.example.com:8000/hello")
+        response.rethrow()
+        self.assertEqual(response.body, b"Hello world!")
+
+
+class ResolveTimeoutTestCase(AsyncHTTPTestCase):
+    def setUp(self):
+        self.cleanup_event = Event()
+        test = self
+
+        # Dummy Resolver subclass that never finishes.
+        class BadResolver(Resolver):
+            @gen.coroutine
+            def resolve(self, *args, **kwargs):
+                yield test.cleanup_event.wait()
+                # Return something valid so the test doesn't raise during cleanup.
+                return [(socket.AF_INET, ("127.0.0.1", test.get_http_port()))]
+
+        super().setUp()
+        self.http_client = SimpleAsyncHTTPClient(resolver=BadResolver())
+
+    def get_app(self):
+        return Application([url("/hello", HelloWorldHandler)])
+
+    def test_resolve_timeout(self):
+        with self.assertRaises(HTTPTimeoutError):
+            self.fetch("/hello", connect_timeout=0.1, raise_error=True)
+
+        # Let the hanging coroutine clean up after itself
+        self.cleanup_event.set()
+        self.io_loop.run_sync(lambda: gen.sleep(0))
+
+
+class MaxHeaderSizeTest(AsyncHTTPTestCase):
+    def get_app(self):
+        class SmallHeaders(RequestHandler):
+            def get(self):
+                self.set_header("X-Filler", "a" * 100)
+                self.write("ok")
+
+        class LargeHeaders(RequestHandler):
+            def get(self):
+                self.set_header("X-Filler", "a" * 1000)
+                self.write("ok")
+
+        return Application([("/small", SmallHeaders), ("/large", LargeHeaders)])
+
+    def get_http_client(self):
+        return SimpleAsyncHTTPClient(max_header_size=1024)
+
+    def test_small_headers(self):
+        response = self.fetch("/small")
+        response.rethrow()
+        self.assertEqual(response.body, b"ok")
+
+    def test_large_headers(self):
+        with ExpectLog(gen_log, "Unsatisfiable read", level=logging.INFO):
+            with self.assertRaises(UnsatisfiableReadError):
+                self.fetch("/large", raise_error=True)
+
+
+class MaxBodySizeTest(AsyncHTTPTestCase):
+    def get_app(self):
+        class SmallBody(RequestHandler):
+            def get(self):
+                self.write("a" * 1024 * 64)
+
+        class LargeBody(RequestHandler):
+            def get(self):
+                self.write("a" * 1024 * 100)
+
+        return Application([("/small", SmallBody), ("/large", LargeBody)])
+
+    def get_http_client(self):
+        return SimpleAsyncHTTPClient(max_body_size=1024 * 64)
+
+    def test_small_body(self):
+        response = self.fetch("/small")
+        response.rethrow()
+        self.assertEqual(response.body, b"a" * 1024 * 64)
+
+    def test_large_body(self):
+        with ExpectLog(
+            gen_log,
+            "Malformed HTTP message from None: Content-Length too long",
+            level=logging.INFO,
+        ):
+            with self.assertRaises(HTTPStreamClosedError):
+                self.fetch("/large", raise_error=True)
+
+
+class MaxBufferSizeTest(AsyncHTTPTestCase):
+    def get_app(self):
+        class LargeBody(RequestHandler):
+            def get(self):
+                self.write("a" * 1024 * 100)
+
+        return Application([("/large", LargeBody)])
+
+    def get_http_client(self):
+        # 100KB body with 64KB buffer
+        return SimpleAsyncHTTPClient(
+            max_body_size=1024 * 100, max_buffer_size=1024 * 64
+        )
+
+    def test_large_body(self):
+        response = self.fetch("/large")
+        response.rethrow()
+        self.assertEqual(response.body, b"a" * 1024 * 100)
+
+
+class ChunkedWithContentLengthTest(AsyncHTTPTestCase):
+    def get_app(self):
+        class ChunkedWithContentLength(RequestHandler):
+            def get(self):
+                # Add an invalid Transfer-Encoding to the response
+                self.set_header("Transfer-Encoding", "chunked")
+                self.write("Hello world")
+
+        return Application([("/chunkwithcl", ChunkedWithContentLength)])
+
+    def get_http_client(self):
+        return SimpleAsyncHTTPClient()
+
+    def test_chunked_with_content_length(self):
+        # Make sure the invalid headers are detected
+        with ExpectLog(
+            gen_log,
+            (
+                "Malformed HTTP message from None: Response "
+                "with both Transfer-Encoding and Content-Length"
+            ),
+            level=logging.INFO,
+        ):
+            with self.assertRaises(HTTPStreamClosedError):
+                self.fetch("/chunkwithcl", raise_error=True)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static/dir/index.html b/venv/lib/python3.9/site-packages/tornado/test/static/dir/index.html
new file mode 100644
index 00000000..e1cd9d8a
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static/dir/index.html
@@ -0,0 +1 @@
+this is the index
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static/robots.txt b/venv/lib/python3.9/site-packages/tornado/test/static/robots.txt
new file mode 100644
index 00000000..1f53798b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static/robots.txt
@@ -0,0 +1,2 @@
+User-agent: *
+Disallow: /
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml
new file mode 100644
index 00000000..35ea0e29
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<data>
+    <country name="Liechtenstein">
+        <rank>1</rank>
+        <year>2008</year>
+        <gdppc>141100</gdppc>
+        <neighbor name="Austria" direction="E"/>
+        <neighbor name="Switzerland" direction="W"/>
+    </country>
+    <country name="Singapore">
+        <rank>4</rank>
+        <year>2011</year>
+        <gdppc>59900</gdppc>
+        <neighbor name="Malaysia" direction="N"/>
+    </country>
+    <country name="Panama">
+        <rank>68</rank>
+        <year>2011</year>
+        <gdppc>13600</gdppc>
+        <neighbor name="Costa Rica" direction="W"/>
+        <neighbor name="Colombia" direction="E"/>
+    </country>
+</data>
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.bz2 b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.bz2
new file mode 100644
index 00000000..44dc6633
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.bz2
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.gz b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.gz
new file mode 100644
index 00000000..c0fd5e6f
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static/sample.xml.gz
diff --git a/venv/lib/python3.9/site-packages/tornado/test/static_foo.txt b/venv/lib/python3.9/site-packages/tornado/test/static_foo.txt
new file mode 100644
index 00000000..bdb44f39
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/static_foo.txt
@@ -0,0 +1,2 @@
+This file should not be served by StaticFileHandler even though
+its name starts with "static".
diff --git a/venv/lib/python3.9/site-packages/tornado/test/tcpclient_test.py b/venv/lib/python3.9/site-packages/tornado/test/tcpclient_test.py
new file mode 100644
index 00000000..ecfc82d6
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/tcpclient_test.py
@@ -0,0 +1,439 @@
+#
+# Copyright 2014 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+from contextlib import closing
+import getpass
+import os
+import socket
+import unittest
+
+from tornado.concurrent import Future
+from tornado.netutil import bind_sockets, Resolver
+from tornado.queues import Queue
+from tornado.tcpclient import TCPClient, _Connector
+from tornado.tcpserver import TCPServer
+from tornado.testing import AsyncTestCase, gen_test
+from tornado.test.util import skipIfNoIPv6, refusing_port, skipIfNonUnix
+from tornado.gen import TimeoutError
+
+import typing
+
+if typing.TYPE_CHECKING:
+    from tornado.iostream import IOStream  # noqa: F401
+    from typing import List, Dict, Tuple  # noqa: F401
+
+# Fake address families for testing.  Used in place of AF_INET
+# and AF_INET6 because some installations do not have AF_INET6.
+AF1, AF2 = 1, 2
+
+
+class TestTCPServer(TCPServer):
+    def __init__(self, family):
+        super().__init__()
+        self.streams = []  # type: List[IOStream]
+        self.queue = Queue()  # type: Queue[IOStream]
+        sockets = bind_sockets(0, "localhost", family)
+        self.add_sockets(sockets)
+        self.port = sockets[0].getsockname()[1]
+
+    def handle_stream(self, stream, address):
+        self.streams.append(stream)
+        self.queue.put(stream)
+
+    def stop(self):
+        super().stop()
+        for stream in self.streams:
+            stream.close()
+
+
+class TCPClientTest(AsyncTestCase):
+    def setUp(self):
+        super().setUp()
+        self.server = None
+        self.client = TCPClient()
+
+    def start_server(self, family):
+        if family == socket.AF_UNSPEC and "TRAVIS" in os.environ:
+            self.skipTest("dual-stack servers often have port conflicts on travis")
+        self.server = TestTCPServer(family)
+        return self.server.port
+
+    def stop_server(self):
+        if self.server is not None:
+            self.server.stop()
+            self.server = None
+
+    def tearDown(self):
+        self.client.close()
+        self.stop_server()
+        super().tearDown()
+
+    def skipIfLocalhostV4(self):
+        # The port used here doesn't matter, but some systems require it
+        # to be non-zero if we do not also pass AI_PASSIVE.
+        addrinfo = self.io_loop.run_sync(lambda: Resolver().resolve("localhost", 80))
+        families = set(addr[0] for addr in addrinfo)
+        if socket.AF_INET6 not in families:
+            self.skipTest("localhost does not resolve to ipv6")
+
+    @gen_test
+    def do_test_connect(self, family, host, source_ip=None, source_port=None):
+        port = self.start_server(family)
+        stream = yield self.client.connect(
+            host,
+            port,
+            source_ip=source_ip,
+            source_port=source_port,
+            af=family,
+        )
+        assert self.server is not None
+        server_stream = yield self.server.queue.get()
+        with closing(stream):
+            stream.write(b"hello")
+            data = yield server_stream.read_bytes(5)
+            self.assertEqual(data, b"hello")
+
+    def test_connect_ipv4_ipv4(self):
+        self.do_test_connect(socket.AF_INET, "127.0.0.1")
+
+    def test_connect_ipv4_dual(self):
+        self.do_test_connect(socket.AF_INET, "localhost")
+
+    @skipIfNoIPv6
+    def test_connect_ipv6_ipv6(self):
+        self.skipIfLocalhostV4()
+        self.do_test_connect(socket.AF_INET6, "::1")
+
+    @skipIfNoIPv6
+    def test_connect_ipv6_dual(self):
+        self.skipIfLocalhostV4()
+        if Resolver.configured_class().__name__.endswith("TwistedResolver"):
+            self.skipTest("TwistedResolver does not support multiple addresses")
+        self.do_test_connect(socket.AF_INET6, "localhost")
+
+    def test_connect_unspec_ipv4(self):
+        self.do_test_connect(socket.AF_UNSPEC, "127.0.0.1")
+
+    @skipIfNoIPv6
+    def test_connect_unspec_ipv6(self):
+        self.skipIfLocalhostV4()
+        self.do_test_connect(socket.AF_UNSPEC, "::1")
+
+    def test_connect_unspec_dual(self):
+        self.do_test_connect(socket.AF_UNSPEC, "localhost")
+
+    @gen_test
+    def test_refused_ipv4(self):
+        cleanup_func, port = refusing_port()
+        self.addCleanup(cleanup_func)
+        with self.assertRaises(IOError):
+            yield self.client.connect("127.0.0.1", port)
+
+    def test_source_ip_fail(self):
+        """Fail when trying to use the source IP Address '8.8.8.8'."""
+        self.assertRaises(
+            socket.error,
+            self.do_test_connect,
+            socket.AF_INET,
+            "127.0.0.1",
+            source_ip="8.8.8.8",
+        )
+
+    def test_source_ip_success(self):
+        """Success when trying to use the source IP Address '127.0.0.1'."""
+        self.do_test_connect(socket.AF_INET, "127.0.0.1", source_ip="127.0.0.1")
+
+    @skipIfNonUnix
+    def test_source_port_fail(self):
+        """Fail when trying to use source port 1."""
+        if getpass.getuser() == "root":
+            # Root can use any port so we can't easily force this to fail.
+            # This is mainly relevant for docker.
+            self.skipTest("running as root")
+        self.assertRaises(
+            socket.error,
+            self.do_test_connect,
+            socket.AF_INET,
+            "127.0.0.1",
+            source_port=1,
+        )
+
+    @gen_test
+    def test_connect_timeout(self):
+        timeout = 0.05
+
+        class TimeoutResolver(Resolver):
+            def resolve(self, *args, **kwargs):
+                return Future()  # never completes
+
+        with self.assertRaises(TimeoutError):
+            yield TCPClient(resolver=TimeoutResolver()).connect(
+                "1.2.3.4", 12345, timeout=timeout
+            )
+
+
+class TestConnectorSplit(unittest.TestCase):
+    def test_one_family(self):
+        # These addresses aren't in the right format, but split doesn't care.
+        primary, secondary = _Connector.split([(AF1, "a"), (AF1, "b")])
+        self.assertEqual(primary, [(AF1, "a"), (AF1, "b")])
+        self.assertEqual(secondary, [])
+
+    def test_mixed(self):
+        primary, secondary = _Connector.split(
+            [(AF1, "a"), (AF2, "b"), (AF1, "c"), (AF2, "d")]
+        )
+        self.assertEqual(primary, [(AF1, "a"), (AF1, "c")])
+        self.assertEqual(secondary, [(AF2, "b"), (AF2, "d")])
+
+
+class ConnectorTest(AsyncTestCase):
+    class FakeStream(object):
+        def __init__(self):
+            self.closed = False
+
+        def close(self):
+            self.closed = True
+
+    def setUp(self):
+        super().setUp()
+        self.connect_futures = (
+            {}
+        )  # type: Dict[Tuple[int, typing.Any], Future[ConnectorTest.FakeStream]]
+        self.streams = {}  # type: Dict[typing.Any, ConnectorTest.FakeStream]
+        self.addrinfo = [(AF1, "a"), (AF1, "b"), (AF2, "c"), (AF2, "d")]
+
+    def tearDown(self):
+        # Unless explicitly checked (and popped) in the test, we shouldn't
+        # be closing any streams
+        for stream in self.streams.values():
+            self.assertFalse(stream.closed)
+        super().tearDown()
+
+    def create_stream(self, af, addr):
+        stream = ConnectorTest.FakeStream()
+        self.streams[addr] = stream
+        future = Future()  # type: Future[ConnectorTest.FakeStream]
+        self.connect_futures[(af, addr)] = future
+        return stream, future
+
+    def assert_pending(self, *keys):
+        self.assertEqual(sorted(self.connect_futures.keys()), sorted(keys))
+
+    def resolve_connect(self, af, addr, success):
+        future = self.connect_futures.pop((af, addr))
+        if success:
+            future.set_result(self.streams[addr])
+        else:
+            self.streams.pop(addr)
+            future.set_exception(IOError())
+        # Run the loop to allow callbacks to be run.
+        self.io_loop.add_callback(self.stop)
+        self.wait()
+
+    def assert_connector_streams_closed(self, conn):
+        for stream in conn.streams:
+            self.assertTrue(stream.closed)
+
+    def start_connect(self, addrinfo):
+        conn = _Connector(addrinfo, self.create_stream)
+        # Give it a huge timeout; we'll trigger timeouts manually.
+        future = conn.start(3600, connect_timeout=self.io_loop.time() + 3600)
+        return conn, future
+
+    def test_immediate_success(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assertEqual(list(self.connect_futures.keys()), [(AF1, "a")])
+        self.resolve_connect(AF1, "a", True)
+        self.assertEqual(future.result(), (AF1, "a", self.streams["a"]))
+
+    def test_immediate_failure(self):
+        # Fail with just one address.
+        conn, future = self.start_connect([(AF1, "a")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assertRaises(IOError, future.result)
+
+    def test_one_family_second_try(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        self.resolve_connect(AF1, "b", True)
+        self.assertEqual(future.result(), (AF1, "b", self.streams["b"]))
+
+    def test_one_family_second_try_failure(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        self.resolve_connect(AF1, "b", False)
+        self.assertRaises(IOError, future.result)
+
+    def test_one_family_second_try_timeout(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        # trigger the timeout while the first lookup is pending;
+        # nothing happens.
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        self.resolve_connect(AF1, "b", True)
+        self.assertEqual(future.result(), (AF1, "b", self.streams["b"]))
+
+    def test_two_families_immediate_failure(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"), (AF2, "c"))
+        self.resolve_connect(AF1, "b", False)
+        self.resolve_connect(AF2, "c", True)
+        self.assertEqual(future.result(), (AF2, "c", self.streams["c"]))
+
+    def test_two_families_timeout(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"), (AF2, "c"))
+        self.resolve_connect(AF2, "c", True)
+        self.assertEqual(future.result(), (AF2, "c", self.streams["c"]))
+        # resolving 'a' after the connection has completed doesn't start 'b'
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending()
+
+    def test_success_after_timeout(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"), (AF2, "c"))
+        self.resolve_connect(AF1, "a", True)
+        self.assertEqual(future.result(), (AF1, "a", self.streams["a"]))
+        # resolving 'c' after completion closes the connection.
+        self.resolve_connect(AF2, "c", True)
+        self.assertTrue(self.streams.pop("c").closed)
+
+    def test_all_fail(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"), (AF2, "c"))
+        self.resolve_connect(AF2, "c", False)
+        self.assert_pending((AF1, "a"), (AF2, "d"))
+        self.resolve_connect(AF2, "d", False)
+        # one queue is now empty
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        self.assertFalse(future.done())
+        self.resolve_connect(AF1, "b", False)
+        self.assertRaises(IOError, future.result)
+
+    def test_one_family_timeout_after_connect_timeout(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        conn.on_connect_timeout()
+        # the connector will close all streams on connect timeout, we
+        # should explicitly pop the connect_future.
+        self.connect_futures.pop((AF1, "a"))
+        self.assertTrue(self.streams.pop("a").closed)
+        conn.on_timeout()
+        # if the future is set with TimeoutError, we will not iterate next
+        # possible address.
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 1)
+        self.assert_connector_streams_closed(conn)
+        self.assertRaises(TimeoutError, future.result)
+
+    def test_one_family_success_before_connect_timeout(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", True)
+        conn.on_connect_timeout()
+        self.assert_pending()
+        self.assertEqual(self.streams["a"].closed, False)
+        # success stream will be pop
+        self.assertEqual(len(conn.streams), 0)
+        # streams in connector should be closed after connect timeout
+        self.assert_connector_streams_closed(conn)
+        self.assertEqual(future.result(), (AF1, "a", self.streams["a"]))
+
+    def test_one_family_second_try_after_connect_timeout(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        conn.on_connect_timeout()
+        self.connect_futures.pop((AF1, "b"))
+        self.assertTrue(self.streams.pop("b").closed)
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 2)
+        self.assert_connector_streams_closed(conn)
+        self.assertRaises(TimeoutError, future.result)
+
+    def test_one_family_second_try_failure_before_connect_timeout(self):
+        conn, future = self.start_connect([(AF1, "a"), (AF1, "b")])
+        self.assert_pending((AF1, "a"))
+        self.resolve_connect(AF1, "a", False)
+        self.assert_pending((AF1, "b"))
+        self.resolve_connect(AF1, "b", False)
+        conn.on_connect_timeout()
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 2)
+        self.assert_connector_streams_closed(conn)
+        self.assertRaises(IOError, future.result)
+
+    def test_two_family_timeout_before_connect_timeout(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"), (AF2, "c"))
+        conn.on_connect_timeout()
+        self.connect_futures.pop((AF1, "a"))
+        self.assertTrue(self.streams.pop("a").closed)
+        self.connect_futures.pop((AF2, "c"))
+        self.assertTrue(self.streams.pop("c").closed)
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 2)
+        self.assert_connector_streams_closed(conn)
+        self.assertRaises(TimeoutError, future.result)
+
+    def test_two_family_success_after_timeout(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_timeout()
+        self.assert_pending((AF1, "a"), (AF2, "c"))
+        self.resolve_connect(AF1, "a", True)
+        # if one of streams succeed, connector will close all other streams
+        self.connect_futures.pop((AF2, "c"))
+        self.assertTrue(self.streams.pop("c").closed)
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 1)
+        self.assert_connector_streams_closed(conn)
+        self.assertEqual(future.result(), (AF1, "a", self.streams["a"]))
+
+    def test_two_family_timeout_after_connect_timeout(self):
+        conn, future = self.start_connect(self.addrinfo)
+        self.assert_pending((AF1, "a"))
+        conn.on_connect_timeout()
+        self.connect_futures.pop((AF1, "a"))
+        self.assertTrue(self.streams.pop("a").closed)
+        self.assert_pending()
+        conn.on_timeout()
+        # if the future is set with TimeoutError, connector will not
+        # trigger secondary address.
+        self.assert_pending()
+        self.assertEqual(len(conn.streams), 1)
+        self.assert_connector_streams_closed(conn)
+        self.assertRaises(TimeoutError, future.result)
diff --git a/venv/lib/python3.9/site-packages/tornado/test/tcpserver_test.py b/venv/lib/python3.9/site-packages/tornado/test/tcpserver_test.py
new file mode 100644
index 00000000..c636c858
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/tcpserver_test.py
@@ -0,0 +1,230 @@
+import socket
+import subprocess
+import sys
+import textwrap
+import unittest
+
+from tornado import gen
+from tornado.iostream import IOStream
+from tornado.log import app_log
+from tornado.tcpserver import TCPServer
+from tornado.test.util import skipIfNonUnix
+from tornado.testing import AsyncTestCase, ExpectLog, bind_unused_port, gen_test
+
+from typing import Tuple
+
+
+class TCPServerTest(AsyncTestCase):
+    @gen_test
+    def test_handle_stream_coroutine_logging(self):
+        # handle_stream may be a coroutine and any exception in its
+        # Future will be logged.
+        class TestServer(TCPServer):
+            @gen.coroutine
+            def handle_stream(self, stream, address):
+                yield stream.read_bytes(len(b"hello"))
+                stream.close()
+                1 / 0
+
+        server = client = None
+        try:
+            sock, port = bind_unused_port()
+            server = TestServer()
+            server.add_socket(sock)
+            client = IOStream(socket.socket())
+            with ExpectLog(app_log, "Exception in callback"):
+                yield client.connect(("localhost", port))
+                yield client.write(b"hello")
+                yield client.read_until_close()
+                yield gen.moment
+        finally:
+            if server is not None:
+                server.stop()
+            if client is not None:
+                client.close()
+
+    @gen_test
+    def test_handle_stream_native_coroutine(self):
+        # handle_stream may be a native coroutine.
+
+        class TestServer(TCPServer):
+            async def handle_stream(self, stream, address):
+                stream.write(b"data")
+                stream.close()
+
+        sock, port = bind_unused_port()
+        server = TestServer()
+        server.add_socket(sock)
+        client = IOStream(socket.socket())
+        yield client.connect(("localhost", port))
+        result = yield client.read_until_close()
+        self.assertEqual(result, b"data")
+        server.stop()
+        client.close()
+
+    def test_stop_twice(self):
+        sock, port = bind_unused_port()
+        server = TCPServer()
+        server.add_socket(sock)
+        server.stop()
+        server.stop()
+
+    @gen_test
+    def test_stop_in_callback(self):
+        # Issue #2069: calling server.stop() in a loop callback should not
+        # raise EBADF when the loop handles other server connection
+        # requests in the same loop iteration
+
+        class TestServer(TCPServer):
+            @gen.coroutine
+            def handle_stream(self, stream, address):
+                server.stop()  # type: ignore
+                yield stream.read_until_close()
+
+        sock, port = bind_unused_port()
+        server = TestServer()
+        server.add_socket(sock)
+        server_addr = ("localhost", port)
+        N = 40
+        clients = [IOStream(socket.socket()) for i in range(N)]
+        connected_clients = []
+
+        @gen.coroutine
+        def connect(c):
+            try:
+                yield c.connect(server_addr)
+            except EnvironmentError:
+                pass
+            else:
+                connected_clients.append(c)
+
+        yield [connect(c) for c in clients]
+
+        self.assertGreater(len(connected_clients), 0, "all clients failed connecting")
+        try:
+            if len(connected_clients) == N:
+                # Ideally we'd make the test deterministic, but we're testing
+                # for a race condition in combination with the system's TCP stack...
+                self.skipTest(
+                    "at least one client should fail connecting "
+                    "for the test to be meaningful"
+                )
+        finally:
+            for c in connected_clients:
+                c.close()
+
+        # Here tearDown() would re-raise the EBADF encountered in the IO loop
+
+
+@skipIfNonUnix
+class TestMultiprocess(unittest.TestCase):
+    # These tests verify that the two multiprocess examples from the
+    # TCPServer docs work. Both tests start a server with three worker
+    # processes, each of which prints its task id to stdout (a single
+    # byte, so we don't have to worry about atomicity of the shared
+    # stdout stream) and then exits.
+    def run_subproc(self, code: str) -> Tuple[str, str]:
+        try:
+            result = subprocess.run(
+                [sys.executable, "-Werror::DeprecationWarning"],
+                capture_output=True,
+                input=code,
+                encoding="utf8",
+                check=True,
+            )
+        except subprocess.CalledProcessError as e:
+            raise RuntimeError(
+                f"Process returned {e.returncode} stdout={e.stdout} stderr={e.stderr}"
+            ) from e
+        return result.stdout, result.stderr
+
+    def test_listen_single(self):
+        # As a sanity check, run the single-process version through this test
+        # harness too.
+        code = textwrap.dedent(
+            """
+            import asyncio
+            from tornado.tcpserver import TCPServer
+
+            async def main():
+                server = TCPServer()
+                server.listen(0, address='127.0.0.1')
+
+            asyncio.run(main())
+            print('012', end='')
+        """
+        )
+        out, err = self.run_subproc(code)
+        self.assertEqual("".join(sorted(out)), "012")
+        self.assertEqual(err, "")
+
+    def test_bind_start(self):
+        code = textwrap.dedent(
+            """
+            import warnings
+
+            from tornado.ioloop import IOLoop
+            from tornado.process import task_id
+            from tornado.tcpserver import TCPServer
+
+            warnings.simplefilter("ignore", DeprecationWarning)
+
+            server = TCPServer()
+            server.bind(0, address='127.0.0.1')
+            server.start(3)
+            IOLoop.current().run_sync(lambda: None)
+            print(task_id(), end='')
+        """
+        )
+        out, err = self.run_subproc(code)
+        self.assertEqual("".join(sorted(out)), "012")
+        self.assertEqual(err, "")
+
+    def test_add_sockets(self):
+        code = textwrap.dedent(
+            """
+            import asyncio
+            from tornado.netutil import bind_sockets
+            from tornado.process import fork_processes, task_id
+            from tornado.ioloop import IOLoop
+            from tornado.tcpserver import TCPServer
+
+            sockets = bind_sockets(0, address='127.0.0.1')
+            fork_processes(3)
+            async def post_fork_main():
+                server = TCPServer()
+                server.add_sockets(sockets)
+            asyncio.run(post_fork_main())
+            print(task_id(), end='')
+        """
+        )
+        out, err = self.run_subproc(code)
+        self.assertEqual("".join(sorted(out)), "012")
+        self.assertEqual(err, "")
+
+    def test_listen_multi_reuse_port(self):
+        code = textwrap.dedent(
+            """
+            import asyncio
+            import socket
+            from tornado.netutil import bind_sockets
+            from tornado.process import task_id, fork_processes
+            from tornado.tcpserver import TCPServer
+
+            # Pick an unused port which we will be able to bind to multiple times.
+            (sock,) = bind_sockets(0, address='127.0.0.1',
+                family=socket.AF_INET, reuse_port=True)
+            port = sock.getsockname()[1]
+
+            fork_processes(3)
+
+            async def main():
+                server = TCPServer()
+                server.listen(port, address='127.0.0.1', reuse_port=True)
+            asyncio.run(main())
+            print(task_id(), end='')
+            """
+        )
+        out, err = self.run_subproc(code)
+        self.assertEqual("".join(sorted(out)), "012")
+        self.assertEqual(err, "")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/template_test.py b/venv/lib/python3.9/site-packages/tornado/test/template_test.py
new file mode 100644
index 00000000..801de50b
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/template_test.py
@@ -0,0 +1,536 @@
+import os
+import traceback
+import unittest
+
+from tornado.escape import utf8, native_str, to_unicode
+from tornado.template import Template, DictLoader, ParseError, Loader
+from tornado.util import ObjectDict
+
+import typing  # noqa: F401
+
+
+class TemplateTest(unittest.TestCase):
+    def test_simple(self):
+        template = Template("Hello {{ name }}!")
+        self.assertEqual(template.generate(name="Ben"), b"Hello Ben!")
+
+    def test_bytes(self):
+        template = Template("Hello {{ name }}!")
+        self.assertEqual(template.generate(name=utf8("Ben")), b"Hello Ben!")
+
+    def test_expressions(self):
+        template = Template("2 + 2 = {{ 2 + 2 }}")
+        self.assertEqual(template.generate(), b"2 + 2 = 4")
+
+    def test_comment(self):
+        template = Template("Hello{# TODO i18n #} {{ name }}!")
+        self.assertEqual(template.generate(name=utf8("Ben")), b"Hello Ben!")
+
+    def test_include(self):
+        loader = DictLoader(
+            {
+                "index.html": '{% include "header.html" %}\nbody text',
+                "header.html": "header text",
+            }
+        )
+        self.assertEqual(
+            loader.load("index.html").generate(), b"header text\nbody text"
+        )
+
+    def test_extends(self):
+        loader = DictLoader(
+            {
+                "base.html": """\
+<title>{% block title %}default title{% end %}</title>
+<body>{% block body %}default body{% end %}</body>
+""",
+                "page.html": """\
+{% extends "base.html" %}
+{% block title %}page title{% end %}
+{% block body %}page body{% end %}
+""",
+            }
+        )
+        self.assertEqual(
+            loader.load("page.html").generate(),
+            b"<title>page title</title>\n<body>page body</body>\n",
+        )
+
+    def test_relative_load(self):
+        loader = DictLoader(
+            {
+                "a/1.html": "{% include '2.html' %}",
+                "a/2.html": "{% include '../b/3.html' %}",
+                "b/3.html": "ok",
+            }
+        )
+        self.assertEqual(loader.load("a/1.html").generate(), b"ok")
+
+    def test_escaping(self):
+        self.assertRaises(ParseError, lambda: Template("{{"))
+        self.assertRaises(ParseError, lambda: Template("{%"))
+        self.assertEqual(Template("{{!").generate(), b"{{")
+        self.assertEqual(Template("{%!").generate(), b"{%")
+        self.assertEqual(Template("{#!").generate(), b"{#")
+        self.assertEqual(
+            Template("{{ 'expr' }} {{!jquery expr}}").generate(),
+            b"expr {{jquery expr}}",
+        )
+
+    def test_unicode_template(self):
+        template = Template(utf8("\u00e9"))
+        self.assertEqual(template.generate(), utf8("\u00e9"))
+
+    def test_unicode_literal_expression(self):
+        # Unicode literals should be usable in templates.  Note that this
+        # test simulates unicode characters appearing directly in the
+        # template file (with utf8 encoding), i.e. \u escapes would not
+        # be used in the template file itself.
+        template = Template(utf8('{{ "\u00e9" }}'))
+        self.assertEqual(template.generate(), utf8("\u00e9"))
+
+    def test_custom_namespace(self):
+        loader = DictLoader(
+            {"test.html": "{{ inc(5) }}"}, namespace={"inc": lambda x: x + 1}
+        )
+        self.assertEqual(loader.load("test.html").generate(), b"6")
+
+    def test_apply(self):
+        def upper(s):
+            return s.upper()
+
+        template = Template(utf8("{% apply upper %}foo{% end %}"))
+        self.assertEqual(template.generate(upper=upper), b"FOO")
+
+    def test_unicode_apply(self):
+        def upper(s):
+            return to_unicode(s).upper()
+
+        template = Template(utf8("{% apply upper %}foo \u00e9{% end %}"))
+        self.assertEqual(template.generate(upper=upper), utf8("FOO \u00c9"))
+
+    def test_bytes_apply(self):
+        def upper(s):
+            return utf8(to_unicode(s).upper())
+
+        template = Template(utf8("{% apply upper %}foo \u00e9{% end %}"))
+        self.assertEqual(template.generate(upper=upper), utf8("FOO \u00c9"))
+
+    def test_if(self):
+        template = Template(utf8("{% if x > 4 %}yes{% else %}no{% end %}"))
+        self.assertEqual(template.generate(x=5), b"yes")
+        self.assertEqual(template.generate(x=3), b"no")
+
+    def test_if_empty_body(self):
+        template = Template(utf8("{% if True %}{% else %}{% end %}"))
+        self.assertEqual(template.generate(), b"")
+
+    def test_try(self):
+        template = Template(
+            utf8(
+                """{% try %}
+try{% set y = 1/x %}
+{% except %}-except
+{% else %}-else
+{% finally %}-finally
+{% end %}"""
+            )
+        )
+        self.assertEqual(template.generate(x=1), b"\ntry\n-else\n-finally\n")
+        self.assertEqual(template.generate(x=0), b"\ntry-except\n-finally\n")
+
+    def test_comment_directive(self):
+        template = Template(utf8("{% comment blah blah %}foo"))
+        self.assertEqual(template.generate(), b"foo")
+
+    def test_break_continue(self):
+        template = Template(
+            utf8(
+                """\
+{% for i in range(10) %}
+    {% if i == 2 %}
+        {% continue %}
+    {% end %}
+    {{ i }}
+    {% if i == 6 %}
+        {% break %}
+    {% end %}
+{% end %}"""
+            )
+        )
+        result = template.generate()
+        # remove extraneous whitespace
+        result = b"".join(result.split())
+        self.assertEqual(result, b"013456")
+
+    def test_break_outside_loop(self):
+        try:
+            Template(utf8("{% break %}"))
+            raise Exception("Did not get expected exception")
+        except ParseError:
+            pass
+
+    def test_break_in_apply(self):
+        # This test verifies current behavior, although of course it would
+        # be nice if apply didn't cause seemingly unrelated breakage
+        try:
+            Template(
+                utf8("{% for i in [] %}{% apply foo %}{% break %}{% end %}{% end %}")
+            )
+            raise Exception("Did not get expected exception")
+        except ParseError:
+            pass
+
+    @unittest.skip("no testable future imports")
+    def test_no_inherit_future(self):
+        # TODO(bdarnell): make a test like this for one of the future
+        # imports available in python 3. Unfortunately they're harder
+        # to use in a template than division was.
+
+        # This file has from __future__ import division...
+        self.assertEqual(1 / 2, 0.5)
+        # ...but the template doesn't
+        template = Template("{{ 1 / 2 }}")
+        self.assertEqual(template.generate(), "0")
+
+    def test_non_ascii_name(self):
+        loader = DictLoader({"t\u00e9st.html": "hello"})
+        self.assertEqual(loader.load("t\u00e9st.html").generate(), b"hello")
+
+
+class StackTraceTest(unittest.TestCase):
+    def test_error_line_number_expression(self):
+        loader = DictLoader(
+            {
+                "test.html": """one
+two{{1/0}}
+three
+        """
+            }
+        )
+        try:
+            loader.load("test.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            self.assertTrue("# test.html:2" in traceback.format_exc())
+
+    def test_error_line_number_directive(self):
+        loader = DictLoader(
+            {
+                "test.html": """one
+two{%if 1/0%}
+three{%end%}
+        """
+            }
+        )
+        try:
+            loader.load("test.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            self.assertTrue("# test.html:2" in traceback.format_exc())
+
+    def test_error_line_number_module(self):
+        loader = None  # type: typing.Optional[DictLoader]
+
+        def load_generate(path, **kwargs):
+            assert loader is not None
+            return loader.load(path).generate(**kwargs)
+
+        loader = DictLoader(
+            {"base.html": "{% module Template('sub.html') %}", "sub.html": "{{1/0}}"},
+            namespace={"_tt_modules": ObjectDict(Template=load_generate)},
+        )
+        try:
+            loader.load("base.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            exc_stack = traceback.format_exc()
+            self.assertTrue("# base.html:1" in exc_stack)
+            self.assertTrue("# sub.html:1" in exc_stack)
+
+    def test_error_line_number_include(self):
+        loader = DictLoader(
+            {"base.html": "{% include 'sub.html' %}", "sub.html": "{{1/0}}"}
+        )
+        try:
+            loader.load("base.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            self.assertTrue("# sub.html:1 (via base.html:1)" in traceback.format_exc())
+
+    def test_error_line_number_extends_base_error(self):
+        loader = DictLoader(
+            {"base.html": "{{1/0}}", "sub.html": "{% extends 'base.html' %}"}
+        )
+        try:
+            loader.load("sub.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            exc_stack = traceback.format_exc()
+        self.assertTrue("# base.html:1" in exc_stack)
+
+    def test_error_line_number_extends_sub_error(self):
+        loader = DictLoader(
+            {
+                "base.html": "{% block 'block' %}{% end %}",
+                "sub.html": """
+{% extends 'base.html' %}
+{% block 'block' %}
+{{1/0}}
+{% end %}
+            """,
+            }
+        )
+        try:
+            loader.load("sub.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            self.assertTrue("# sub.html:4 (via base.html:1)" in traceback.format_exc())
+
+    def test_multi_includes(self):
+        loader = DictLoader(
+            {
+                "a.html": "{% include 'b.html' %}",
+                "b.html": "{% include 'c.html' %}",
+                "c.html": "{{1/0}}",
+            }
+        )
+        try:
+            loader.load("a.html").generate()
+            self.fail("did not get expected exception")
+        except ZeroDivisionError:
+            self.assertTrue(
+                "# c.html:1 (via b.html:1, a.html:1)" in traceback.format_exc()
+            )
+
+
+class ParseErrorDetailTest(unittest.TestCase):
+    def test_details(self):
+        loader = DictLoader({"foo.html": "\n\n{{"})
+        with self.assertRaises(ParseError) as cm:
+            loader.load("foo.html")
+        self.assertEqual("Missing end expression }} at foo.html:3", str(cm.exception))
+        self.assertEqual("foo.html", cm.exception.filename)
+        self.assertEqual(3, cm.exception.lineno)
+
+    def test_custom_parse_error(self):
+        # Make sure that ParseErrors remain compatible with their
+        # pre-4.3 signature.
+        self.assertEqual("asdf at None:0", str(ParseError("asdf")))
+
+
+class AutoEscapeTest(unittest.TestCase):
+    def setUp(self):
+        self.templates = {
+            "escaped.html": "{% autoescape xhtml_escape %}{{ name }}",
+            "unescaped.html": "{% autoescape None %}{{ name }}",
+            "default.html": "{{ name }}",
+            "include.html": """\
+escaped: {% include 'escaped.html' %}
+unescaped: {% include 'unescaped.html' %}
+default: {% include 'default.html' %}
+""",
+            "escaped_block.html": """\
+{% autoescape xhtml_escape %}\
+{% block name %}base: {{ name }}{% end %}""",
+            "unescaped_block.html": """\
+{% autoescape None %}\
+{% block name %}base: {{ name }}{% end %}""",
+            # Extend a base template with different autoescape policy,
+            # with and without overriding the base's blocks
+            "escaped_extends_unescaped.html": """\
+{% autoescape xhtml_escape %}\
+{% extends "unescaped_block.html" %}""",
+            "escaped_overrides_unescaped.html": """\
+{% autoescape xhtml_escape %}\
+{% extends "unescaped_block.html" %}\
+{% block name %}extended: {{ name }}{% end %}""",
+            "unescaped_extends_escaped.html": """\
+{% autoescape None %}\
+{% extends "escaped_block.html" %}""",
+            "unescaped_overrides_escaped.html": """\
+{% autoescape None %}\
+{% extends "escaped_block.html" %}\
+{% block name %}extended: {{ name }}{% end %}""",
+            "raw_expression.html": """\
+{% autoescape xhtml_escape %}\
+expr: {{ name }}
+raw: {% raw name %}""",
+        }
+
+    def test_default_off(self):
+        loader = DictLoader(self.templates, autoescape=None)
+        name = "Bobby <table>s"
+        self.assertEqual(
+            loader.load("escaped.html").generate(name=name), b"Bobby &lt;table&gt;s"
+        )
+        self.assertEqual(
+            loader.load("unescaped.html").generate(name=name), b"Bobby <table>s"
+        )
+        self.assertEqual(
+            loader.load("default.html").generate(name=name), b"Bobby <table>s"
+        )
+
+        self.assertEqual(
+            loader.load("include.html").generate(name=name),
+            b"escaped: Bobby &lt;table&gt;s\n"
+            b"unescaped: Bobby <table>s\n"
+            b"default: Bobby <table>s\n",
+        )
+
+    def test_default_on(self):
+        loader = DictLoader(self.templates, autoescape="xhtml_escape")
+        name = "Bobby <table>s"
+        self.assertEqual(
+            loader.load("escaped.html").generate(name=name), b"Bobby &lt;table&gt;s"
+        )
+        self.assertEqual(
+            loader.load("unescaped.html").generate(name=name), b"Bobby <table>s"
+        )
+        self.assertEqual(
+            loader.load("default.html").generate(name=name), b"Bobby &lt;table&gt;s"
+        )
+
+        self.assertEqual(
+            loader.load("include.html").generate(name=name),
+            b"escaped: Bobby &lt;table&gt;s\n"
+            b"unescaped: Bobby <table>s\n"
+            b"default: Bobby &lt;table&gt;s\n",
+        )
+
+    def test_unextended_block(self):
+        loader = DictLoader(self.templates)
+        name = "<script>"
+        self.assertEqual(
+            loader.load("escaped_block.html").generate(name=name),
+            b"base: &lt;script&gt;",
+        )
+        self.assertEqual(
+            loader.load("unescaped_block.html").generate(name=name), b"base: <script>"
+        )
+
+    def test_extended_block(self):
+        loader = DictLoader(self.templates)
+
+        def render(name):
+            return loader.load(name).generate(name="<script>")
+
+        self.assertEqual(render("escaped_extends_unescaped.html"), b"base: <script>")
+        self.assertEqual(
+            render("escaped_overrides_unescaped.html"), b"extended: &lt;script&gt;"
+        )
+
+        self.assertEqual(
+            render("unescaped_extends_escaped.html"), b"base: &lt;script&gt;"
+        )
+        self.assertEqual(
+            render("unescaped_overrides_escaped.html"), b"extended: <script>"
+        )
+
+    def test_raw_expression(self):
+        loader = DictLoader(self.templates)
+
+        def render(name):
+            return loader.load(name).generate(name='<>&"')
+
+        self.assertEqual(
+            render("raw_expression.html"), b"expr: &lt;&gt;&amp;&quot;\n" b'raw: <>&"'
+        )
+
+    def test_custom_escape(self):
+        loader = DictLoader({"foo.py": "{% autoescape py_escape %}s = {{ name }}\n"})
+
+        def py_escape(s):
+            self.assertEqual(type(s), bytes)
+            return repr(native_str(s))
+
+        def render(template, name):
+            return loader.load(template).generate(py_escape=py_escape, name=name)
+
+        self.assertEqual(render("foo.py", "<html>"), b"s = '<html>'\n")
+        self.assertEqual(render("foo.py", "';sys.exit()"), b"""s = "';sys.exit()"\n""")
+        self.assertEqual(
+            render("foo.py", ["not a string"]), b"""s = "['not a string']"\n"""
+        )
+
+    def test_manual_minimize_whitespace(self):
+        # Whitespace including newlines is allowed within template tags
+        # and directives, and this is one way to avoid long lines while
+        # keeping extra whitespace out of the rendered output.
+        loader = DictLoader(
+            {
+                "foo.txt": """\
+{% for i in items
+  %}{% if i > 0 %}, {% end %}{#
+  #}{{i
+  }}{% end
+%}"""
+            }
+        )
+        self.assertEqual(
+            loader.load("foo.txt").generate(items=range(5)), b"0, 1, 2, 3, 4"
+        )
+
+    def test_whitespace_by_filename(self):
+        # Default whitespace handling depends on the template filename.
+        loader = DictLoader(
+            {
+                "foo.html": "   \n\t\n asdf\t   ",
+                "bar.js": " \n\n\n\t qwer     ",
+                "baz.txt": "\t    zxcv\n\n",
+                "include.html": "  {% include baz.txt %} \n ",
+                "include.txt": "\t\t{% include foo.html %}    ",
+            }
+        )
+
+        # HTML and JS files have whitespace compressed by default.
+        self.assertEqual(loader.load("foo.html").generate(), b"\nasdf ")
+        self.assertEqual(loader.load("bar.js").generate(), b"\nqwer ")
+        # TXT files do not.
+        self.assertEqual(loader.load("baz.txt").generate(), b"\t    zxcv\n\n")
+
+        # Each file maintains its own status even when included in
+        # a file of the other type.
+        self.assertEqual(loader.load("include.html").generate(), b" \t    zxcv\n\n\n")
+        self.assertEqual(loader.load("include.txt").generate(), b"\t\t\nasdf     ")
+
+    def test_whitespace_by_loader(self):
+        templates = {"foo.html": "\t\tfoo\n\n", "bar.txt": "\t\tbar\n\n"}
+        loader = DictLoader(templates, whitespace="all")
+        self.assertEqual(loader.load("foo.html").generate(), b"\t\tfoo\n\n")
+        self.assertEqual(loader.load("bar.txt").generate(), b"\t\tbar\n\n")
+
+        loader = DictLoader(templates, whitespace="single")
+        self.assertEqual(loader.load("foo.html").generate(), b" foo\n")
+        self.assertEqual(loader.load("bar.txt").generate(), b" bar\n")
+
+        loader = DictLoader(templates, whitespace="oneline")
+        self.assertEqual(loader.load("foo.html").generate(), b" foo ")
+        self.assertEqual(loader.load("bar.txt").generate(), b" bar ")
+
+    def test_whitespace_directive(self):
+        loader = DictLoader(
+            {
+                "foo.html": """\
+{% whitespace oneline %}
+    {% for i in range(3) %}
+        {{ i }}
+    {% end %}
+{% whitespace all %}
+    pre\tformatted
+"""
+            }
+        )
+        self.assertEqual(
+            loader.load("foo.html").generate(), b"  0  1  2  \n    pre\tformatted\n"
+        )
+
+
+class TemplateLoaderTest(unittest.TestCase):
+    def setUp(self):
+        self.loader = Loader(os.path.join(os.path.dirname(__file__), "templates"))
+
+    def test_utf8_in_file(self):
+        tmpl = self.loader.load("utf8.html")
+        result = tmpl.generate()
+        self.assertEqual(to_unicode(result).strip(), "H\u00e9llo")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/templates/utf8.html b/venv/lib/python3.9/site-packages/tornado/test/templates/utf8.html
new file mode 100644
index 00000000..c5253dfa
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/templates/utf8.html
@@ -0,0 +1 @@
+Héllo
diff --git a/venv/lib/python3.9/site-packages/tornado/test/test.crt b/venv/lib/python3.9/site-packages/tornado/test/test.crt
new file mode 100644
index 00000000..ffc49b06
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/test.crt
@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----
+MIIDWzCCAkOgAwIBAgIUV4spou0CenmvKqa7Hml/MC+JKiAwDQYJKoZIhvcNAQEL
+BQAwPTELMAkGA1UEBhMCVVMxEzARBgNVBAgMCkNhbGlmb3JuaWExGTAXBgNVBAoM
+EFRvcm5hZG8gV2ViIFRlc3QwHhcNMTgwOTI5MTM1NjQ1WhcNMjgwOTI2MTM1NjQ1
+WjA9MQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5pYTEZMBcGA1UECgwQ
+VG9ybmFkbyBXZWIgVGVzdDCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB
+AKT0LdyI8tW5uwP3ahE8BFSz+j3SsKBDv/0cKvqxVVE6sLEST2s3HjArZvIIG5sb
+iBkWDrqnZ6UKDvB4jlobLGAkepxDbrxHWxK53n0C28XXGLqJQ01TlTZ5rpjttMeg
+5SKNjHbxpOvpUwwQS4br4WjZKKyTGiXpFkFUty+tYVU35/U2yyvreWHmzpHx/25t
+H7O2RBARVwJYKOGPtlH62lQjpIWfVfklY4Ip8Hjl3B6rBxPyBULmVQw0qgoZn648
+oa4oLjs0wnYBz01gVjNMDHej52SsB/ieH7W1TxFMzqOlcvHh41uFbQJPgcXsruSS
+9Z4twzSWkUp2vk/C//4Sz38CAwEAAaNTMFEwHQYDVR0OBBYEFLf8fQ5+u8sDWAd3
+r5ZjZ5MmDWJeMB8GA1UdIwQYMBaAFLf8fQ5+u8sDWAd3r5ZjZ5MmDWJeMA8GA1Ud
+EwEB/wQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEBADkkm3pIb9IeqVNmQ2uhQOgw
+UwyToTYUHNTb/Nm5lzBTBqC8gbXAS24RQ30AB/7G115Uxeo+YMKfITxm/CgR+vhF
+F59/YrzwXj+G8bdbuVl/UbB6f9RSp+Zo93rUZAtPWr77gxLUrcwSRzzDwxFjC2nC
+6eigbkvt1OQY775RwnFAt7HKPclE0Out+cGJIboJuO1f3r57ZdyFH0GzbZEff/7K
+atGXohijWJjYvU4mk0KFHORZrcBpsv9cfkFbmgVmiRwxRJ1tLauHM3Ne+VfqYE5M
+4rTStSyz3ASqVKJ2iFMQueNR/tUOuDlfRt+0nhJMuYSSkW+KTgnwyOGU9cv+mxA=
+-----END CERTIFICATE-----
diff --git a/venv/lib/python3.9/site-packages/tornado/test/test.key b/venv/lib/python3.9/site-packages/tornado/test/test.key
new file mode 100644
index 00000000..7cb7d8d2
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/test.key
@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----
+MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCk9C3ciPLVubsD
+92oRPARUs/o90rCgQ7/9HCr6sVVROrCxEk9rNx4wK2byCBubG4gZFg66p2elCg7w
+eI5aGyxgJHqcQ268R1sSud59AtvF1xi6iUNNU5U2ea6Y7bTHoOUijYx28aTr6VMM
+EEuG6+Fo2Siskxol6RZBVLcvrWFVN+f1Nssr63lh5s6R8f9ubR+ztkQQEVcCWCjh
+j7ZR+tpUI6SFn1X5JWOCKfB45dweqwcT8gVC5lUMNKoKGZ+uPKGuKC47NMJ2Ac9N
+YFYzTAx3o+dkrAf4nh+1tU8RTM6jpXLx4eNbhW0CT4HF7K7kkvWeLcM0lpFKdr5P
+wv/+Es9/AgMBAAECggEABi6AaXtYXloPgB6NgwfUwbfc8OQsalUfpMShd7OdluW0
+KW6eO05de0ClIvzay/1EJGyHMMeFQtIVrT1XWFkcWJ4FWkXMqJGkABenFtg8lDVz
+X8o1E3jGZrw4ptKBq9mDvL/BO9PiclTUH+ecbPn6AIvi0lTQ7grGIryiAM9mjmLy
+jpCwoutF2LD4RPNg8vqWe/Z1rQw5lp8FOHhRwPooHHeoq1bSrp8dqvVAwAam7Mmf
+uFgI8jrNycPgr2cwEEtbq2TQ625MhVnCpwT+kErmAStfbXXuqv1X1ZZgiNxf+61C
+OL0bhPRVIHmmjiK/5qHRuN4Q5u9/Yp2SJ4W5xadSQQKBgQDR7dnOlYYQiaoPJeD/
+7jcLVJbWwbr7bE19O/QpYAtkA/FtGlKr+hQxPhK6OYp+in8eHf+ga/NSAjCWRBoh
+MNAVCJtiirHo2tFsLFOmlJpGL9n3sX8UnkJN90oHfWrzJ8BZnXaSw2eOuyw8LLj+
+Q+ISl6Go8/xfsuy3EDv4AP1wCwKBgQDJJ4vEV3Kr+bc6N/xeu+G0oHvRAWwuQpcx
+9D+XpnqbJbFDnWKNE7oGsDCs8Qjr0CdFUN1pm1ppITDZ5N1cWuDg/47ZAXqEK6D1
+z13S7O0oQPlnsPL7mHs2Vl73muAaBPAojFvceHHfccr7Z94BXqKsiyfaWz6kclT/
+Nl4JTdsC3QKBgQCeYgozL2J/da2lUhnIXcyPstk+29kbueFYu/QBh2HwqnzqqLJ4
+5+t2H3P3plQUFp/DdDSZrvhcBiTsKiNgqThEtkKtfSCvIvBf4a2W/4TJsW6MzxCm
+2KQDuK/UqM4Y+APKWN/N6Lln2VWNbNyBkWuuRVKFatccyJyJnSjxeqW7cwKBgGyN
+idCYPIrwROAHLItXKvOWE5t0ABRq3TsZC2RkdA/b5HCPs4pclexcEriRjvXrK/Yt
+MH94Ve8b+UftSUQ4ytjBMS6MrLg87y0YDhLwxv8NKUq65DXAUOW+8JsAmmWQOqY3
+MK+m1BT4TMklgVoN3w3sPsKIsSJ/jLz5cv/kYweFAoGAG4iWU1378tI2Ts/Fngsv
+7eoWhoda77Y9D0Yoy20aN9VdMHzIYCBOubtRPEuwgaReNwbUBWap01J63yY/fF3K
+8PTz6covjoOJqxQJOvM7nM0CsJawG9ccw3YXyd9KgRIdSt6ooEhb7N8W2EXYoKl3
+g1i2t41Q/SC3HUGC5mJjpO8=
+-----END PRIVATE KEY-----
diff --git a/venv/lib/python3.9/site-packages/tornado/test/testing_test.py b/venv/lib/python3.9/site-packages/tornado/test/testing_test.py
new file mode 100644
index 00000000..0429feee
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/testing_test.py
@@ -0,0 +1,345 @@
+from tornado import gen, ioloop
+from tornado.httpserver import HTTPServer
+from tornado.locks import Event
+from tornado.testing import AsyncHTTPTestCase, AsyncTestCase, bind_unused_port, gen_test
+from tornado.web import Application
+import asyncio
+import contextlib
+import inspect
+import gc
+import os
+import platform
+import sys
+import traceback
+import unittest
+import warnings
+
+
+@contextlib.contextmanager
+def set_environ(name, value):
+    old_value = os.environ.get(name)
+    os.environ[name] = value
+
+    try:
+        yield
+    finally:
+        if old_value is None:
+            del os.environ[name]
+        else:
+            os.environ[name] = old_value
+
+
+class AsyncTestCaseTest(AsyncTestCase):
+    def test_wait_timeout(self):
+        time = self.io_loop.time
+
+        # Accept default 5-second timeout, no error
+        self.io_loop.add_timeout(time() + 0.01, self.stop)
+        self.wait()
+
+        # Timeout passed to wait()
+        self.io_loop.add_timeout(time() + 1, self.stop)
+        with self.assertRaises(self.failureException):
+            self.wait(timeout=0.01)
+
+        # Timeout set with environment variable
+        self.io_loop.add_timeout(time() + 1, self.stop)
+        with set_environ("ASYNC_TEST_TIMEOUT", "0.01"):
+            with self.assertRaises(self.failureException):
+                self.wait()
+
+    def test_subsequent_wait_calls(self):
+        """
+        This test makes sure that a second call to wait()
+        clears the first timeout.
+        """
+        # The first wait ends with time left on the clock
+        self.io_loop.add_timeout(self.io_loop.time() + 0.00, self.stop)
+        self.wait(timeout=0.1)
+        # The second wait has enough time for itself but would fail if the
+        # first wait's deadline were still in effect.
+        self.io_loop.add_timeout(self.io_loop.time() + 0.2, self.stop)
+        self.wait(timeout=0.4)
+
+
+class LeakTest(AsyncTestCase):
+    def tearDown(self):
+        super().tearDown()
+        # Trigger a gc to make warnings more deterministic.
+        gc.collect()
+
+    def test_leaked_coroutine(self):
+        # This test verifies that "leaked" coroutines are shut down
+        # without triggering warnings like "task was destroyed but it
+        # is pending". If this test were to fail, it would fail
+        # because runtests.py detected unexpected output to stderr.
+        event = Event()
+
+        async def callback():
+            try:
+                await event.wait()
+            except asyncio.CancelledError:
+                pass
+
+        self.io_loop.add_callback(callback)
+        self.io_loop.add_callback(self.stop)
+        self.wait()
+
+
+class AsyncHTTPTestCaseTest(AsyncHTTPTestCase):
+    def setUp(self):
+        super().setUp()
+        # Bind a second port.
+        sock, port = bind_unused_port()
+        app = Application()
+        server = HTTPServer(app, **self.get_httpserver_options())
+        server.add_socket(sock)
+        self.second_port = port
+        self.second_server = server
+
+    def get_app(self):
+        return Application()
+
+    def test_fetch_segment(self):
+        path = "/path"
+        response = self.fetch(path)
+        self.assertEqual(response.request.url, self.get_url(path))
+
+    def test_fetch_full_http_url(self):
+        # Ensure that self.fetch() recognizes absolute urls and does
+        # not transform them into references to our main test server.
+        path = "http://127.0.0.1:%d/path" % self.second_port
+
+        response = self.fetch(path)
+        self.assertEqual(response.request.url, path)
+
+    def tearDown(self):
+        self.second_server.stop()
+        super().tearDown()
+
+
+class AsyncTestCaseWrapperTest(unittest.TestCase):
+    def test_undecorated_generator(self):
+        class Test(AsyncTestCase):
+            def test_gen(self):
+                yield
+
+        test = Test("test_gen")
+        result = unittest.TestResult()
+        test.run(result)
+        self.assertEqual(len(result.errors), 1)
+        self.assertIn("should be decorated", result.errors[0][1])
+
+    @unittest.skipIf(
+        platform.python_implementation() == "PyPy",
+        "pypy destructor warnings cannot be silenced",
+    )
+    @unittest.skipIf(
+        sys.version_info >= (3, 12), "py312 has its own check for test case returns"
+    )
+    def test_undecorated_coroutine(self):
+        class Test(AsyncTestCase):
+            async def test_coro(self):
+                pass
+
+        test = Test("test_coro")
+        result = unittest.TestResult()
+
+        # Silence "RuntimeWarning: coroutine 'test_coro' was never awaited".
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore")
+            test.run(result)
+
+        self.assertEqual(len(result.errors), 1)
+        self.assertIn("should be decorated", result.errors[0][1])
+
+    def test_undecorated_generator_with_skip(self):
+        class Test(AsyncTestCase):
+            @unittest.skip("don't run this")
+            def test_gen(self):
+                yield
+
+        test = Test("test_gen")
+        result = unittest.TestResult()
+        test.run(result)
+        self.assertEqual(len(result.errors), 0)
+        self.assertEqual(len(result.skipped), 1)
+
+    def test_other_return(self):
+        class Test(AsyncTestCase):
+            def test_other_return(self):
+                return 42
+
+        test = Test("test_other_return")
+        result = unittest.TestResult()
+        test.run(result)
+        self.assertEqual(len(result.errors), 1)
+        self.assertIn("Return value from test method ignored", result.errors[0][1])
+
+    def test_unwrap(self):
+        class Test(AsyncTestCase):
+            def test_foo(self):
+                pass
+
+        test = Test("test_foo")
+        self.assertIs(
+            inspect.unwrap(test.test_foo),
+            test.test_foo.orig_method,  # type: ignore[attr-defined]
+        )
+
+
+class SetUpTearDownTest(unittest.TestCase):
+    def test_set_up_tear_down(self):
+        """
+        This test makes sure that AsyncTestCase calls super methods for
+        setUp and tearDown.
+
+        InheritBoth is a subclass of both AsyncTestCase and
+        SetUpTearDown, with the ordering so that the super of
+        AsyncTestCase will be SetUpTearDown.
+        """
+        events = []
+        result = unittest.TestResult()
+
+        class SetUpTearDown(unittest.TestCase):
+            def setUp(self):
+                events.append("setUp")
+
+            def tearDown(self):
+                events.append("tearDown")
+
+        class InheritBoth(AsyncTestCase, SetUpTearDown):
+            def test(self):
+                events.append("test")
+
+        InheritBoth("test").run(result)
+        expected = ["setUp", "test", "tearDown"]
+        self.assertEqual(expected, events)
+
+
+class AsyncHTTPTestCaseSetUpTearDownTest(unittest.TestCase):
+    def test_tear_down_releases_app_and_http_server(self):
+        result = unittest.TestResult()
+
+        class SetUpTearDown(AsyncHTTPTestCase):
+            def get_app(self):
+                return Application()
+
+            def test(self):
+                self.assertTrue(hasattr(self, "_app"))
+                self.assertTrue(hasattr(self, "http_server"))
+
+        test = SetUpTearDown("test")
+        test.run(result)
+        self.assertFalse(hasattr(test, "_app"))
+        self.assertFalse(hasattr(test, "http_server"))
+
+
+class GenTest(AsyncTestCase):
+    def setUp(self):
+        super().setUp()
+        self.finished = False
+
+    def tearDown(self):
+        self.assertTrue(self.finished)
+        super().tearDown()
+
+    @gen_test
+    def test_sync(self):
+        self.finished = True
+
+    @gen_test
+    def test_async(self):
+        yield gen.moment
+        self.finished = True
+
+    def test_timeout(self):
+        # Set a short timeout and exceed it.
+        @gen_test(timeout=0.1)
+        def test(self):
+            yield gen.sleep(1)
+
+        # This can't use assertRaises because we need to inspect the
+        # exc_info triple (and not just the exception object)
+        try:
+            test(self)
+            self.fail("did not get expected exception")
+        except ioloop.TimeoutError:
+            # The stack trace should blame the add_timeout line, not just
+            # unrelated IOLoop/testing internals.
+            self.assertIn("gen.sleep(1)", traceback.format_exc())
+
+        self.finished = True
+
+    def test_no_timeout(self):
+        # A test that does not exceed its timeout should succeed.
+        @gen_test(timeout=1)
+        def test(self):
+            yield gen.sleep(0.1)
+
+        test(self)
+        self.finished = True
+
+    def test_timeout_environment_variable(self):
+        @gen_test(timeout=0.5)
+        def test_long_timeout(self):
+            yield gen.sleep(0.25)
+
+        # Uses provided timeout of 0.5 seconds, doesn't time out.
+        with set_environ("ASYNC_TEST_TIMEOUT", "0.1"):
+            test_long_timeout(self)
+
+        self.finished = True
+
+    def test_no_timeout_environment_variable(self):
+        @gen_test(timeout=0.01)
+        def test_short_timeout(self):
+            yield gen.sleep(1)
+
+        # Uses environment-variable timeout of 0.1, times out.
+        with set_environ("ASYNC_TEST_TIMEOUT", "0.1"):
+            with self.assertRaises(ioloop.TimeoutError):
+                test_short_timeout(self)
+
+        self.finished = True
+
+    def test_with_method_args(self):
+        @gen_test
+        def test_with_args(self, *args):
+            self.assertEqual(args, ("test",))
+            yield gen.moment
+
+        test_with_args(self, "test")
+        self.finished = True
+
+    def test_with_method_kwargs(self):
+        @gen_test
+        def test_with_kwargs(self, **kwargs):
+            self.assertDictEqual(kwargs, {"test": "test"})
+            yield gen.moment
+
+        test_with_kwargs(self, test="test")
+        self.finished = True
+
+    def test_native_coroutine(self):
+        @gen_test
+        async def test(self):
+            self.finished = True
+
+        test(self)
+
+    def test_native_coroutine_timeout(self):
+        # Set a short timeout and exceed it.
+        @gen_test(timeout=0.1)
+        async def test(self):
+            await gen.sleep(1)
+
+        try:
+            test(self)
+            self.fail("did not get expected exception")
+        except ioloop.TimeoutError:
+            self.finished = True
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/twisted_test.py b/venv/lib/python3.9/site-packages/tornado/test/twisted_test.py
new file mode 100644
index 00000000..7f983a73
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/twisted_test.py
@@ -0,0 +1,64 @@
+# Author: Ovidiu Predescu
+# Date: July 2011
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import unittest
+
+from tornado.testing import AsyncTestCase, gen_test
+
+try:
+    from twisted.internet.defer import (  # type: ignore
+        inlineCallbacks,
+        returnValue,
+    )
+
+    have_twisted = True
+except ImportError:
+    have_twisted = False
+else:
+    # Not used directly but needed for `yield deferred` to work.
+    import tornado.platform.twisted  # noqa: F401
+
+skipIfNoTwisted = unittest.skipUnless(have_twisted, "twisted module not present")
+
+
+@skipIfNoTwisted
+class ConvertDeferredTest(AsyncTestCase):
+    @gen_test
+    def test_success(self):
+        @inlineCallbacks
+        def fn():
+            if False:
+                # inlineCallbacks doesn't work with regular functions;
+                # must have a yield even if it's unreachable.
+                yield
+            returnValue(42)
+
+        res = yield fn()
+        self.assertEqual(res, 42)
+
+    @gen_test
+    def test_failure(self):
+        @inlineCallbacks
+        def fn():
+            if False:
+                yield
+            1 / 0
+
+        with self.assertRaises(ZeroDivisionError):
+            yield fn()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/venv/lib/python3.9/site-packages/tornado/test/util.py b/venv/lib/python3.9/site-packages/tornado/test/util.py
new file mode 100644
index 00000000..bcb9bbde
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/util.py
@@ -0,0 +1,114 @@
+import contextlib
+import os
+import platform
+import socket
+import sys
+import textwrap
+import typing  # noqa: F401
+import unittest
+import warnings
+
+from tornado.testing import bind_unused_port
+
+skipIfNonUnix = unittest.skipIf(
+    os.name != "posix" or sys.platform == "cygwin", "non-unix platform"
+)
+
+# travis-ci.org runs our tests in an overworked virtual machine, which makes
+# timing-related tests unreliable.
+skipOnTravis = unittest.skipIf(
+    "TRAVIS" in os.environ, "timing tests unreliable on travis"
+)
+
+# Set the environment variable NO_NETWORK=1 to disable any tests that
+# depend on an external network.
+skipIfNoNetwork = unittest.skipIf("NO_NETWORK" in os.environ, "network access disabled")
+
+skipNotCPython = unittest.skipIf(
+    platform.python_implementation() != "CPython", "Not CPython implementation"
+)
+
+# Used for tests affected by
+# https://bitbucket.org/pypy/pypy/issues/2616/incomplete-error-handling-in
+# TODO: remove this after pypy3 5.8 is obsolete.
+skipPypy3V58 = unittest.skipIf(
+    platform.python_implementation() == "PyPy"
+    and sys.version_info > (3,)
+    and sys.pypy_version_info < (5, 9),  # type: ignore
+    "pypy3 5.8 has buggy ssl module",
+)
+
+
+def _detect_ipv6():
+    if not socket.has_ipv6:
+        # socket.has_ipv6 check reports whether ipv6 was present at compile
+        # time. It's usually true even when ipv6 doesn't work for other reasons.
+        return False
+    sock = None
+    try:
+        sock = socket.socket(socket.AF_INET6)
+        sock.bind(("::1", 0))
+    except socket.error:
+        return False
+    finally:
+        if sock is not None:
+            sock.close()
+    return True
+
+
+skipIfNoIPv6 = unittest.skipIf(not _detect_ipv6(), "ipv6 support not present")
+
+
+def refusing_port():
+    """Returns a local port number that will refuse all connections.
+
+    Return value is (cleanup_func, port); the cleanup function
+    must be called to free the port to be reused.
+    """
+    # On travis-ci, port numbers are reassigned frequently. To avoid
+    # collisions with other tests, we use an open client-side socket's
+    # ephemeral port number to ensure that nothing can listen on that
+    # port.
+    server_socket, port = bind_unused_port()
+    server_socket.setblocking(True)
+    client_socket = socket.socket()
+    client_socket.connect(("127.0.0.1", port))
+    conn, client_addr = server_socket.accept()
+    conn.close()
+    server_socket.close()
+    return (client_socket.close, client_addr[1])
+
+
+def exec_test(caller_globals, caller_locals, s):
+    """Execute ``s`` in a given context and return the result namespace.
+
+    Used to define functions for tests in particular python
+    versions that would be syntax errors in older versions.
+    """
+    # Flatten the real global and local namespace into our fake
+    # globals: it's all global from the perspective of code defined
+    # in s.
+    global_namespace = dict(caller_globals, **caller_locals)  # type: ignore
+    local_namespace = {}  # type: typing.Dict[str, typing.Any]
+    exec(textwrap.dedent(s), global_namespace, local_namespace)
+    return local_namespace
+
+
+def subTest(test, *args, **kwargs):
+    """Compatibility shim for unittest.TestCase.subTest.
+
+    Usage: ``with tornado.test.util.subTest(self, x=x):``
+    """
+    try:
+        subTest = test.subTest  # py34+
+    except AttributeError:
+        subTest = contextlib.contextmanager(lambda *a, **kw: (yield))
+    return subTest(*args, **kwargs)
+
+
+@contextlib.contextmanager
+def ignore_deprecation():
+    """Context manager to ignore deprecation warnings."""
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", DeprecationWarning)
+        yield
diff --git a/venv/lib/python3.9/site-packages/tornado/test/util_test.py b/venv/lib/python3.9/site-packages/tornado/test/util_test.py
new file mode 100644
index 00000000..02cf0c19
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/util_test.py
@@ -0,0 +1,308 @@
+from io import StringIO
+import re
+import sys
+import datetime
+import unittest
+
+import tornado
+from tornado.escape import utf8
+from tornado.util import (
+    raise_exc_info,
+    Configurable,
+    exec_in,
+    ArgReplacer,
+    timedelta_to_seconds,
+    import_object,
+    re_unescape,
+    is_finalizing,
+)
+
+import typing
+from typing import cast
+
+if typing.TYPE_CHECKING:
+    from typing import Dict, Any  # noqa: F401
+
+
+class RaiseExcInfoTest(unittest.TestCase):
+    def test_two_arg_exception(self):
+        # This test would fail on python 3 if raise_exc_info were simply
+        # a three-argument raise statement, because TwoArgException
+        # doesn't have a "copy constructor"
+        class TwoArgException(Exception):
+            def __init__(self, a, b):
+                super().__init__()
+                self.a, self.b = a, b
+
+        try:
+            raise TwoArgException(1, 2)
+        except TwoArgException:
+            exc_info = sys.exc_info()
+        try:
+            raise_exc_info(exc_info)
+            self.fail("didn't get expected exception")
+        except TwoArgException as e:
+            self.assertIs(e, exc_info[1])
+
+
+class TestConfigurable(Configurable):
+    @classmethod
+    def configurable_base(cls):
+        return TestConfigurable
+
+    @classmethod
+    def configurable_default(cls):
+        return TestConfig1
+
+
+class TestConfig1(TestConfigurable):
+    def initialize(self, pos_arg=None, a=None):
+        self.a = a
+        self.pos_arg = pos_arg
+
+
+class TestConfig2(TestConfigurable):
+    def initialize(self, pos_arg=None, b=None):
+        self.b = b
+        self.pos_arg = pos_arg
+
+
+class TestConfig3(TestConfigurable):
+    # TestConfig3 is a configuration option that is itself configurable.
+    @classmethod
+    def configurable_base(cls):
+        return TestConfig3
+
+    @classmethod
+    def configurable_default(cls):
+        return TestConfig3A
+
+
+class TestConfig3A(TestConfig3):
+    def initialize(self, a=None):
+        self.a = a
+
+
+class TestConfig3B(TestConfig3):
+    def initialize(self, b=None):
+        self.b = b
+
+
+class ConfigurableTest(unittest.TestCase):
+    def setUp(self):
+        self.saved = TestConfigurable._save_configuration()
+        self.saved3 = TestConfig3._save_configuration()
+
+    def tearDown(self):
+        TestConfigurable._restore_configuration(self.saved)
+        TestConfig3._restore_configuration(self.saved3)
+
+    def checkSubclasses(self):
+        # no matter how the class is configured, it should always be
+        # possible to instantiate the subclasses directly
+        self.assertIsInstance(TestConfig1(), TestConfig1)
+        self.assertIsInstance(TestConfig2(), TestConfig2)
+
+        obj = TestConfig1(a=1)
+        self.assertEqual(obj.a, 1)
+        obj2 = TestConfig2(b=2)
+        self.assertEqual(obj2.b, 2)
+
+    def test_default(self):
+        # In these tests we combine a typing.cast to satisfy mypy with
+        # a runtime type-assertion. Without the cast, mypy would only
+        # let us access attributes of the base class.
+        obj = cast(TestConfig1, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig1)
+        self.assertIs(obj.a, None)
+
+        obj = cast(TestConfig1, TestConfigurable(a=1))
+        self.assertIsInstance(obj, TestConfig1)
+        self.assertEqual(obj.a, 1)
+
+        self.checkSubclasses()
+
+    def test_config_class(self):
+        TestConfigurable.configure(TestConfig2)
+        obj = cast(TestConfig2, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertIs(obj.b, None)
+
+        obj = cast(TestConfig2, TestConfigurable(b=2))
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertEqual(obj.b, 2)
+
+        self.checkSubclasses()
+
+    def test_config_str(self):
+        TestConfigurable.configure("tornado.test.util_test.TestConfig2")
+        obj = cast(TestConfig2, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertIs(obj.b, None)
+
+        obj = cast(TestConfig2, TestConfigurable(b=2))
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertEqual(obj.b, 2)
+
+        self.checkSubclasses()
+
+    def test_config_args(self):
+        TestConfigurable.configure(None, a=3)
+        obj = cast(TestConfig1, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig1)
+        self.assertEqual(obj.a, 3)
+
+        obj = cast(TestConfig1, TestConfigurable(42, a=4))
+        self.assertIsInstance(obj, TestConfig1)
+        self.assertEqual(obj.a, 4)
+        self.assertEqual(obj.pos_arg, 42)
+
+        self.checkSubclasses()
+        # args bound in configure don't apply when using the subclass directly
+        obj = TestConfig1()
+        self.assertIs(obj.a, None)
+
+    def test_config_class_args(self):
+        TestConfigurable.configure(TestConfig2, b=5)
+        obj = cast(TestConfig2, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertEqual(obj.b, 5)
+
+        obj = cast(TestConfig2, TestConfigurable(42, b=6))
+        self.assertIsInstance(obj, TestConfig2)
+        self.assertEqual(obj.b, 6)
+        self.assertEqual(obj.pos_arg, 42)
+
+        self.checkSubclasses()
+        # args bound in configure don't apply when using the subclass directly
+        obj = TestConfig2()
+        self.assertIs(obj.b, None)
+
+    def test_config_multi_level(self):
+        TestConfigurable.configure(TestConfig3, a=1)
+        obj = cast(TestConfig3A, TestConfigurable())
+        self.assertIsInstance(obj, TestConfig3A)
+        self.assertEqual(obj.a, 1)
+
+        TestConfigurable.configure(TestConfig3)
+        TestConfig3.configure(TestConfig3B, b=2)
+        obj2 = cast(TestConfig3B, TestConfigurable())
+        self.assertIsInstance(obj2, TestConfig3B)
+        self.assertEqual(obj2.b, 2)
+
+    def test_config_inner_level(self):
+        # The inner level can be used even when the outer level
+        # doesn't point to it.
+        obj = TestConfig3()
+        self.assertIsInstance(obj, TestConfig3A)
+
+        TestConfig3.configure(TestConfig3B)
+        obj = TestConfig3()
+        self.assertIsInstance(obj, TestConfig3B)
+
+        # Configuring the base doesn't configure the inner.
+        obj2 = TestConfigurable()
+        self.assertIsInstance(obj2, TestConfig1)
+        TestConfigurable.configure(TestConfig2)
+
+        obj3 = TestConfigurable()
+        self.assertIsInstance(obj3, TestConfig2)
+
+        obj = TestConfig3()
+        self.assertIsInstance(obj, TestConfig3B)
+
+
+class UnicodeLiteralTest(unittest.TestCase):
+    def test_unicode_escapes(self):
+        self.assertEqual(utf8("\u00e9"), b"\xc3\xa9")
+
+
+class ExecInTest(unittest.TestCase):
+    # TODO(bdarnell): make a version of this test for one of the new
+    # future imports available in python 3.
+    @unittest.skip("no testable future imports")
+    def test_no_inherit_future(self):
+        # This file has from __future__ import print_function...
+        f = StringIO()
+        print("hello", file=f)
+        # ...but the template doesn't
+        exec_in('print >> f, "world"', dict(f=f))
+        self.assertEqual(f.getvalue(), "hello\nworld\n")
+
+
+class ArgReplacerTest(unittest.TestCase):
+    def setUp(self):
+        def function(x, y, callback=None, z=None):
+            pass
+
+        self.replacer = ArgReplacer(function, "callback")
+
+    def test_omitted(self):
+        args = (1, 2)
+        kwargs = dict()  # type: Dict[str, Any]
+        self.assertIs(self.replacer.get_old_value(args, kwargs), None)
+        self.assertEqual(
+            self.replacer.replace("new", args, kwargs),
+            (None, (1, 2), dict(callback="new")),
+        )
+
+    def test_position(self):
+        args = (1, 2, "old", 3)
+        kwargs = dict()  # type: Dict[str, Any]
+        self.assertEqual(self.replacer.get_old_value(args, kwargs), "old")
+        self.assertEqual(
+            self.replacer.replace("new", args, kwargs),
+            ("old", [1, 2, "new", 3], dict()),
+        )
+
+    def test_keyword(self):
+        args = (1,)
+        kwargs = dict(y=2, callback="old", z=3)
+        self.assertEqual(self.replacer.get_old_value(args, kwargs), "old")
+        self.assertEqual(
+            self.replacer.replace("new", args, kwargs),
+            ("old", (1,), dict(y=2, callback="new", z=3)),
+        )
+
+
+class TimedeltaToSecondsTest(unittest.TestCase):
+    def test_timedelta_to_seconds(self):
+        time_delta = datetime.timedelta(hours=1)
+        self.assertEqual(timedelta_to_seconds(time_delta), 3600.0)
+
+
+class ImportObjectTest(unittest.TestCase):
+    def test_import_member(self):
+        self.assertIs(import_object("tornado.escape.utf8"), utf8)
+
+    def test_import_member_unicode(self):
+        self.assertIs(import_object("tornado.escape.utf8"), utf8)
+
+    def test_import_module(self):
+        self.assertIs(import_object("tornado.escape"), tornado.escape)
+
+    def test_import_module_unicode(self):
+        # The internal implementation of __import__ differs depending on
+        # whether the thing being imported is a module or not.
+        # This variant requires a byte string in python 2.
+        self.assertIs(import_object("tornado.escape"), tornado.escape)
+
+
+class ReUnescapeTest(unittest.TestCase):
+    def test_re_unescape(self):
+        test_strings = ("/favicon.ico", "index.html", "Hello, World!", "!$@#%;")
+        for string in test_strings:
+            self.assertEqual(string, re_unescape(re.escape(string)))
+
+    def test_re_unescape_raises_error_on_invalid_input(self):
+        with self.assertRaises(ValueError):
+            re_unescape("\\d")
+        with self.assertRaises(ValueError):
+            re_unescape("\\b")
+        with self.assertRaises(ValueError):
+            re_unescape("\\Z")
+
+
+class IsFinalizingTest(unittest.TestCase):
+    def test_basic(self):
+        self.assertFalse(is_finalizing())
diff --git a/venv/lib/python3.9/site-packages/tornado/test/web_test.py b/venv/lib/python3.9/site-packages/tornado/test/web_test.py
new file mode 100644
index 00000000..c2d057c5
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/web_test.py
@@ -0,0 +1,3262 @@
+from tornado.concurrent import Future
+from tornado import gen
+from tornado.escape import (
+    json_decode,
+    utf8,
+    to_unicode,
+    recursive_unicode,
+    native_str,
+    to_basestring,
+)
+from tornado.httpclient import HTTPClientError
+from tornado.httputil import format_timestamp
+from tornado.iostream import IOStream
+from tornado import locale
+from tornado.locks import Event
+from tornado.log import app_log, gen_log
+from tornado.simple_httpclient import SimpleAsyncHTTPClient
+from tornado.template import DictLoader
+from tornado.testing import AsyncHTTPTestCase, AsyncTestCase, ExpectLog, gen_test
+from tornado.test.util import ignore_deprecation
+from tornado.util import ObjectDict, unicode_type
+from tornado.web import (
+    Application,
+    RequestHandler,
+    StaticFileHandler,
+    RedirectHandler as WebRedirectHandler,
+    HTTPError,
+    MissingArgumentError,
+    ErrorHandler,
+    authenticated,
+    url,
+    _create_signature_v1,
+    create_signed_value,
+    decode_signed_value,
+    get_signature_key_version,
+    UIModule,
+    Finish,
+    stream_request_body,
+    removeslash,
+    addslash,
+    GZipContentEncoding,
+)
+
+import binascii
+import contextlib
+import copy
+import datetime
+import email.utils
+import gzip
+from io import BytesIO
+import itertools
+import logging
+import os
+import re
+import socket
+import typing  # noqa: F401
+import unittest
+import urllib.parse
+
+
+def relpath(*a):
+    return os.path.join(os.path.dirname(__file__), *a)
+
+
+class WebTestCase(AsyncHTTPTestCase):
+    """Base class for web tests that also supports WSGI mode.
+
+    Override get_handlers and get_app_kwargs instead of get_app.
+    This class is deprecated since WSGI mode is no longer supported.
+    """
+
+    def get_app(self):
+        self.app = Application(self.get_handlers(), **self.get_app_kwargs())
+        return self.app
+
+    def get_handlers(self):
+        raise NotImplementedError()
+
+    def get_app_kwargs(self):
+        return {}
+
+
+class SimpleHandlerTestCase(WebTestCase):
+    """Simplified base class for tests that work with a single handler class.
+
+    To use, define a nested class named ``Handler``.
+    """
+
+    Handler = None
+
+    def get_handlers(self):
+        return [("/", self.Handler)]
+
+
+class HelloHandler(RequestHandler):
+    def get(self):
+        self.write("hello")
+
+
+class CookieTestRequestHandler(RequestHandler):
+    # stub out enough methods to make the signed_cookie functions work
+    def __init__(self, cookie_secret="0123456789", key_version=None):
+        # don't call super.__init__
+        self._cookies = {}  # type: typing.Dict[str, bytes]
+        if key_version is None:
+            self.application = ObjectDict(  # type: ignore
+                settings=dict(cookie_secret=cookie_secret)
+            )
+        else:
+            self.application = ObjectDict(  # type: ignore
+                settings=dict(cookie_secret=cookie_secret, key_version=key_version)
+            )
+
+    def get_cookie(self, name):
+        return self._cookies.get(name)
+
+    def set_cookie(self, name, value, expires_days=None):
+        self._cookies[name] = value
+
+
+# See SignedValueTest below for more.
+class SecureCookieV1Test(unittest.TestCase):
+    def test_round_trip(self):
+        handler = CookieTestRequestHandler()
+        handler.set_signed_cookie("foo", b"bar", version=1)
+        self.assertEqual(handler.get_signed_cookie("foo", min_version=1), b"bar")
+
+    def test_cookie_tampering_future_timestamp(self):
+        handler = CookieTestRequestHandler()
+        # this string base64-encodes to '12345678'
+        handler.set_signed_cookie("foo", binascii.a2b_hex(b"d76df8e7aefc"), version=1)
+        cookie = handler._cookies["foo"]
+        match = re.match(rb"12345678\|([0-9]+)\|([0-9a-f]+)", cookie)
+        assert match is not None
+        timestamp = match.group(1)
+        sig = match.group(2)
+        self.assertEqual(
+            _create_signature_v1(
+                handler.application.settings["cookie_secret"],
+                "foo",
+                "12345678",
+                timestamp,
+            ),
+            sig,
+        )
+        # shifting digits from payload to timestamp doesn't alter signature
+        # (this is not desirable behavior, just confirming that that's how it
+        # works)
+        self.assertEqual(
+            _create_signature_v1(
+                handler.application.settings["cookie_secret"],
+                "foo",
+                "1234",
+                b"5678" + timestamp,
+            ),
+            sig,
+        )
+        # tamper with the cookie
+        handler._cookies["foo"] = utf8(
+            "1234|5678%s|%s" % (to_basestring(timestamp), to_basestring(sig))
+        )
+        # it gets rejected
+        with ExpectLog(gen_log, "Cookie timestamp in future"):
+            self.assertTrue(handler.get_signed_cookie("foo", min_version=1) is None)
+
+    def test_arbitrary_bytes(self):
+        # Secure cookies accept arbitrary data (which is base64 encoded).
+        # Note that normal cookies accept only a subset of ascii.
+        handler = CookieTestRequestHandler()
+        handler.set_signed_cookie("foo", b"\xe9", version=1)
+        self.assertEqual(handler.get_signed_cookie("foo", min_version=1), b"\xe9")
+
+
+# See SignedValueTest below for more.
+class SecureCookieV2Test(unittest.TestCase):
+    KEY_VERSIONS = {0: "ajklasdf0ojaisdf", 1: "aslkjasaolwkjsdf"}
+
+    def test_round_trip(self):
+        handler = CookieTestRequestHandler()
+        handler.set_signed_cookie("foo", b"bar", version=2)
+        self.assertEqual(handler.get_signed_cookie("foo", min_version=2), b"bar")
+
+    def test_key_version_roundtrip(self):
+        handler = CookieTestRequestHandler(
+            cookie_secret=self.KEY_VERSIONS, key_version=0
+        )
+        handler.set_signed_cookie("foo", b"bar")
+        self.assertEqual(handler.get_signed_cookie("foo"), b"bar")
+
+    def test_key_version_roundtrip_differing_version(self):
+        handler = CookieTestRequestHandler(
+            cookie_secret=self.KEY_VERSIONS, key_version=1
+        )
+        handler.set_signed_cookie("foo", b"bar")
+        self.assertEqual(handler.get_signed_cookie("foo"), b"bar")
+
+    def test_key_version_increment_version(self):
+        handler = CookieTestRequestHandler(
+            cookie_secret=self.KEY_VERSIONS, key_version=0
+        )
+        handler.set_signed_cookie("foo", b"bar")
+        new_handler = CookieTestRequestHandler(
+            cookie_secret=self.KEY_VERSIONS, key_version=1
+        )
+        new_handler._cookies = handler._cookies
+        self.assertEqual(new_handler.get_signed_cookie("foo"), b"bar")
+
+    def test_key_version_invalidate_version(self):
+        handler = CookieTestRequestHandler(
+            cookie_secret=self.KEY_VERSIONS, key_version=0
+        )
+        handler.set_signed_cookie("foo", b"bar")
+        new_key_versions = self.KEY_VERSIONS.copy()
+        new_key_versions.pop(0)
+        new_handler = CookieTestRequestHandler(
+            cookie_secret=new_key_versions, key_version=1
+        )
+        new_handler._cookies = handler._cookies
+        self.assertEqual(new_handler.get_signed_cookie("foo"), None)
+
+
+class FinalReturnTest(WebTestCase):
+    final_return = None  # type: Future
+
+    def get_handlers(self):
+        test = self
+
+        class FinishHandler(RequestHandler):
+            @gen.coroutine
+            def get(self):
+                test.final_return = self.finish()
+                yield test.final_return
+
+            @gen.coroutine
+            def post(self):
+                self.write("hello,")
+                yield self.flush()
+                test.final_return = self.finish("world")
+                yield test.final_return
+
+        class RenderHandler(RequestHandler):
+            def create_template_loader(self, path):
+                return DictLoader({"foo.html": "hi"})
+
+            @gen.coroutine
+            def get(self):
+                test.final_return = self.render("foo.html")
+
+        return [("/finish", FinishHandler), ("/render", RenderHandler)]
+
+    def get_app_kwargs(self):
+        return dict(template_path="FinalReturnTest")
+
+    def test_finish_method_return_future(self):
+        response = self.fetch(self.get_url("/finish"))
+        self.assertEqual(response.code, 200)
+        self.assertIsInstance(self.final_return, Future)
+        self.assertTrue(self.final_return.done())
+
+        response = self.fetch(self.get_url("/finish"), method="POST", body=b"")
+        self.assertEqual(response.code, 200)
+        self.assertIsInstance(self.final_return, Future)
+        self.assertTrue(self.final_return.done())
+
+    def test_render_method_return_future(self):
+        response = self.fetch(self.get_url("/render"))
+        self.assertEqual(response.code, 200)
+        self.assertIsInstance(self.final_return, Future)
+
+
+class CookieTest(WebTestCase):
+    def get_handlers(self):
+        class SetCookieHandler(RequestHandler):
+            def get(self):
+                # Try setting cookies with different argument types
+                # to ensure that everything gets encoded correctly
+                self.set_cookie("str", "asdf")
+                self.set_cookie("unicode", "qwer")
+                self.set_cookie("bytes", b"zxcv")
+
+        class GetCookieHandler(RequestHandler):
+            def get(self):
+                cookie = self.get_cookie("foo", "default")
+                assert cookie is not None
+                self.write(cookie)
+
+        class SetCookieDomainHandler(RequestHandler):
+            def get(self):
+                # unicode domain and path arguments shouldn't break things
+                # either (see bug #285)
+                self.set_cookie("unicode_args", "blah", domain="foo.com", path="/foo")
+
+        class SetCookieSpecialCharHandler(RequestHandler):
+            def get(self):
+                self.set_cookie("equals", "a=b")
+                self.set_cookie("semicolon", "a;b")
+                self.set_cookie("quote", 'a"b')
+
+        class SetCookieOverwriteHandler(RequestHandler):
+            def get(self):
+                self.set_cookie("a", "b", domain="example.com")
+                self.set_cookie("c", "d", domain="example.com")
+                # A second call with the same name clobbers the first.
+                # Attributes from the first call are not carried over.
+                self.set_cookie("a", "e")
+
+        class SetCookieMaxAgeHandler(RequestHandler):
+            def get(self):
+                self.set_cookie("foo", "bar", max_age=10)
+
+        class SetCookieExpiresDaysHandler(RequestHandler):
+            def get(self):
+                self.set_cookie("foo", "bar", expires_days=10)
+
+        class SetCookieFalsyFlags(RequestHandler):
+            def get(self):
+                self.set_cookie("a", "1", secure=True)
+                self.set_cookie("b", "1", secure=False)
+                self.set_cookie("c", "1", httponly=True)
+                self.set_cookie("d", "1", httponly=False)
+
+        class SetCookieDeprecatedArgs(RequestHandler):
+            def get(self):
+                # Mixed case is supported, but deprecated
+                self.set_cookie("a", "b", HttpOnly=True, pATH="/foo")
+
+        return [
+            ("/set", SetCookieHandler),
+            ("/get", GetCookieHandler),
+            ("/set_domain", SetCookieDomainHandler),
+            ("/special_char", SetCookieSpecialCharHandler),
+            ("/set_overwrite", SetCookieOverwriteHandler),
+            ("/set_max_age", SetCookieMaxAgeHandler),
+            ("/set_expires_days", SetCookieExpiresDaysHandler),
+            ("/set_falsy_flags", SetCookieFalsyFlags),
+            ("/set_deprecated", SetCookieDeprecatedArgs),
+        ]
+
+    def test_set_cookie(self):
+        response = self.fetch("/set")
+        self.assertEqual(
+            sorted(response.headers.get_list("Set-Cookie")),
+            ["bytes=zxcv; Path=/", "str=asdf; Path=/", "unicode=qwer; Path=/"],
+        )
+
+    def test_get_cookie(self):
+        response = self.fetch("/get", headers={"Cookie": "foo=bar"})
+        self.assertEqual(response.body, b"bar")
+
+        response = self.fetch("/get", headers={"Cookie": 'foo="bar"'})
+        self.assertEqual(response.body, b"bar")
+
+        response = self.fetch("/get", headers={"Cookie": "/=exception;"})
+        self.assertEqual(response.body, b"default")
+
+    def test_set_cookie_domain(self):
+        response = self.fetch("/set_domain")
+        self.assertEqual(
+            response.headers.get_list("Set-Cookie"),
+            ["unicode_args=blah; Domain=foo.com; Path=/foo"],
+        )
+
+    def test_cookie_special_char(self):
+        response = self.fetch("/special_char")
+        headers = sorted(response.headers.get_list("Set-Cookie"))
+        self.assertEqual(len(headers), 3)
+        self.assertEqual(headers[0], 'equals="a=b"; Path=/')
+        self.assertEqual(headers[1], 'quote="a\\"b"; Path=/')
+        # python 2.7 octal-escapes the semicolon; older versions leave it alone
+        self.assertTrue(
+            headers[2] in ('semicolon="a;b"; Path=/', 'semicolon="a\\073b"; Path=/'),
+            headers[2],
+        )
+
+        data = [
+            ("foo=a=b", "a=b"),
+            ('foo="a=b"', "a=b"),
+            ('foo="a;b"', '"a'),  # even quoted, ";" is a delimiter
+            ("foo=a\\073b", "a\\073b"),  # escapes only decoded in quotes
+            ('foo="a\\073b"', "a;b"),
+            ('foo="a\\"b"', 'a"b'),
+        ]
+        for header, expected in data:
+            logging.debug("trying %r", header)
+            response = self.fetch("/get", headers={"Cookie": header})
+            self.assertEqual(response.body, utf8(expected))
+
+    def test_set_cookie_overwrite(self):
+        response = self.fetch("/set_overwrite")
+        headers = response.headers.get_list("Set-Cookie")
+        self.assertEqual(
+            sorted(headers), ["a=e; Path=/", "c=d; Domain=example.com; Path=/"]
+        )
+
+    def test_set_cookie_max_age(self):
+        response = self.fetch("/set_max_age")
+        headers = response.headers.get_list("Set-Cookie")
+        self.assertEqual(sorted(headers), ["foo=bar; Max-Age=10; Path=/"])
+
+    def test_set_cookie_expires_days(self):
+        response = self.fetch("/set_expires_days")
+        header = response.headers.get("Set-Cookie")
+        assert header is not None
+        match = re.match("foo=bar; expires=(?P<expires>.+); Path=/", header)
+        assert match is not None
+
+        expires = datetime.datetime.utcnow() + datetime.timedelta(days=10)
+        parsed = email.utils.parsedate(match.groupdict()["expires"])
+        assert parsed is not None
+        header_expires = datetime.datetime(*parsed[:6])
+        self.assertTrue(abs((expires - header_expires).total_seconds()) < 10)
+
+    def test_set_cookie_false_flags(self):
+        response = self.fetch("/set_falsy_flags")
+        headers = sorted(response.headers.get_list("Set-Cookie"))
+        # The secure and httponly headers are capitalized in py35 and
+        # lowercase in older versions.
+        self.assertEqual(headers[0].lower(), "a=1; path=/; secure")
+        self.assertEqual(headers[1].lower(), "b=1; path=/")
+        self.assertEqual(headers[2].lower(), "c=1; httponly; path=/")
+        self.assertEqual(headers[3].lower(), "d=1; path=/")
+
+    def test_set_cookie_deprecated(self):
+        with ignore_deprecation():
+            response = self.fetch("/set_deprecated")
+        header = response.headers.get("Set-Cookie")
+        self.assertEqual(header, "a=b; HttpOnly; Path=/foo")
+
+
+class AuthRedirectRequestHandler(RequestHandler):
+    def initialize(self, login_url):
+        self.login_url = login_url
+
+    def get_login_url(self):
+        return self.login_url
+
+    @authenticated
+    def get(self):
+        # we'll never actually get here because the test doesn't follow redirects
+        self.send_error(500)
+
+
+class AuthRedirectTest(WebTestCase):
+    def get_handlers(self):
+        return [
+            ("/relative", AuthRedirectRequestHandler, dict(login_url="/login")),
+            (
+                "/absolute",
+                AuthRedirectRequestHandler,
+                dict(login_url="http://example.com/login"),
+            ),
+        ]
+
+    def test_relative_auth_redirect(self):
+        response = self.fetch(self.get_url("/relative"), follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertEqual(response.headers["Location"], "/login?next=%2Frelative")
+
+    def test_absolute_auth_redirect(self):
+        response = self.fetch(self.get_url("/absolute"), follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertTrue(
+            re.match(
+                r"http://example.com/login\?next=http%3A%2F%2F127.0.0.1%3A[0-9]+%2Fabsolute",
+                response.headers["Location"],
+            ),
+            response.headers["Location"],
+        )
+
+
+class ConnectionCloseHandler(RequestHandler):
+    def initialize(self, test):
+        self.test = test
+
+    @gen.coroutine
+    def get(self):
+        self.test.on_handler_waiting()
+        yield self.test.cleanup_event.wait()
+
+    def on_connection_close(self):
+        self.test.on_connection_close()
+
+
+class ConnectionCloseTest(WebTestCase):
+    def get_handlers(self):
+        self.cleanup_event = Event()
+        return [("/", ConnectionCloseHandler, dict(test=self))]
+
+    def test_connection_close(self):
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
+        s.connect(("127.0.0.1", self.get_http_port()))
+        self.stream = IOStream(s)
+        self.stream.write(b"GET / HTTP/1.0\r\n\r\n")
+        self.wait()
+        # Let the hanging coroutine clean up after itself
+        self.cleanup_event.set()
+        self.io_loop.run_sync(lambda: gen.sleep(0))
+
+    def on_handler_waiting(self):
+        logging.debug("handler waiting")
+        self.stream.close()
+
+    def on_connection_close(self):
+        logging.debug("connection closed")
+        self.stop()
+
+
+class EchoHandler(RequestHandler):
+    def get(self, *path_args):
+        # Type checks: web.py interfaces convert argument values to
+        # unicode strings (by default, but see also decode_argument).
+        # In httpserver.py (i.e. self.request.arguments), they're left
+        # as bytes.  Keys are always native strings.
+        for key in self.request.arguments:
+            if type(key) != str:
+                raise Exception("incorrect type for key: %r" % type(key))
+            for bvalue in self.request.arguments[key]:
+                if type(bvalue) != bytes:
+                    raise Exception("incorrect type for value: %r" % type(bvalue))
+            for svalue in self.get_arguments(key):
+                if type(svalue) != unicode_type:
+                    raise Exception("incorrect type for value: %r" % type(svalue))
+        for arg in path_args:
+            if type(arg) != unicode_type:
+                raise Exception("incorrect type for path arg: %r" % type(arg))
+        self.write(
+            dict(
+                path=self.request.path,
+                path_args=path_args,
+                args=recursive_unicode(self.request.arguments),
+            )
+        )
+
+
+class RequestEncodingTest(WebTestCase):
+    def get_handlers(self):
+        return [("/group/(.*)", EchoHandler), ("/slashes/([^/]*)/([^/]*)", EchoHandler)]
+
+    def fetch_json(self, path):
+        return json_decode(self.fetch(path).body)
+
+    def test_group_question_mark(self):
+        # Ensure that url-encoded question marks are handled properly
+        self.assertEqual(
+            self.fetch_json("/group/%3F"),
+            dict(path="/group/%3F", path_args=["?"], args={}),
+        )
+        self.assertEqual(
+            self.fetch_json("/group/%3F?%3F=%3F"),
+            dict(path="/group/%3F", path_args=["?"], args={"?": ["?"]}),
+        )
+
+    def test_group_encoding(self):
+        # Path components and query arguments should be decoded the same way
+        self.assertEqual(
+            self.fetch_json("/group/%C3%A9?arg=%C3%A9"),
+            {
+                "path": "/group/%C3%A9",
+                "path_args": ["\u00e9"],
+                "args": {"arg": ["\u00e9"]},
+            },
+        )
+
+    def test_slashes(self):
+        # Slashes may be escaped to appear as a single "directory" in the path,
+        # but they are then unescaped when passed to the get() method.
+        self.assertEqual(
+            self.fetch_json("/slashes/foo/bar"),
+            dict(path="/slashes/foo/bar", path_args=["foo", "bar"], args={}),
+        )
+        self.assertEqual(
+            self.fetch_json("/slashes/a%2Fb/c%2Fd"),
+            dict(path="/slashes/a%2Fb/c%2Fd", path_args=["a/b", "c/d"], args={}),
+        )
+
+    def test_error(self):
+        # Percent signs (encoded as %25) should not mess up printf-style
+        # messages in logs
+        with ExpectLog(gen_log, ".*Invalid unicode"):
+            self.fetch("/group/?arg=%25%e9")
+
+
+class TypeCheckHandler(RequestHandler):
+    def prepare(self):
+        self.errors = {}  # type: typing.Dict[str, str]
+
+        self.check_type("status", self.get_status(), int)
+
+        # get_argument is an exception from the general rule of using
+        # type str for non-body data mainly for historical reasons.
+        self.check_type("argument", self.get_argument("foo"), unicode_type)
+        self.check_type("cookie_key", list(self.cookies.keys())[0], str)
+        self.check_type("cookie_value", list(self.cookies.values())[0].value, str)
+
+        # Secure cookies return bytes because they can contain arbitrary
+        # data, but regular cookies are native strings.
+        if list(self.cookies.keys()) != ["asdf"]:
+            raise Exception(
+                "unexpected values for cookie keys: %r" % self.cookies.keys()
+            )
+        self.check_type("get_signed_cookie", self.get_signed_cookie("asdf"), bytes)
+        self.check_type("get_cookie", self.get_cookie("asdf"), str)
+
+        self.check_type("xsrf_token", self.xsrf_token, bytes)
+        self.check_type("xsrf_form_html", self.xsrf_form_html(), str)
+
+        self.check_type("reverse_url", self.reverse_url("typecheck", "foo"), str)
+
+        self.check_type("request_summary", self._request_summary(), str)
+
+    def get(self, path_component):
+        # path_component uses type unicode instead of str for consistency
+        # with get_argument()
+        self.check_type("path_component", path_component, unicode_type)
+        self.write(self.errors)
+
+    def post(self, path_component):
+        self.check_type("path_component", path_component, unicode_type)
+        self.write(self.errors)
+
+    def check_type(self, name, obj, expected_type):
+        actual_type = type(obj)
+        if expected_type != actual_type:
+            self.errors[name] = "expected %s, got %s" % (expected_type, actual_type)
+
+
+class DecodeArgHandler(RequestHandler):
+    def decode_argument(self, value, name=None):
+        if type(value) != bytes:
+            raise Exception("unexpected type for value: %r" % type(value))
+        # use self.request.arguments directly to avoid recursion
+        if "encoding" in self.request.arguments:
+            return value.decode(to_unicode(self.request.arguments["encoding"][0]))
+        else:
+            return value
+
+    def get(self, arg):
+        def describe(s):
+            if type(s) == bytes:
+                return ["bytes", native_str(binascii.b2a_hex(s))]
+            elif type(s) == unicode_type:
+                return ["unicode", s]
+            raise Exception("unknown type")
+
+        self.write({"path": describe(arg), "query": describe(self.get_argument("foo"))})
+
+
+class LinkifyHandler(RequestHandler):
+    def get(self):
+        self.render("linkify.html", message="http://example.com")
+
+
+class UIModuleResourceHandler(RequestHandler):
+    def get(self):
+        self.render("page.html", entries=[1, 2])
+
+
+class OptionalPathHandler(RequestHandler):
+    def get(self, path):
+        self.write({"path": path})
+
+
+class MultiHeaderHandler(RequestHandler):
+    def get(self):
+        self.set_header("x-overwrite", "1")
+        self.set_header("X-Overwrite", 2)
+        self.add_header("x-multi", 3)
+        self.add_header("X-Multi", "4")
+
+
+class RedirectHandler(RequestHandler):
+    def get(self):
+        if self.get_argument("permanent", None) is not None:
+            self.redirect("/", permanent=bool(int(self.get_argument("permanent"))))
+        elif self.get_argument("status", None) is not None:
+            self.redirect("/", status=int(self.get_argument("status")))
+        else:
+            raise Exception("didn't get permanent or status arguments")
+
+
+class EmptyFlushCallbackHandler(RequestHandler):
+    @gen.coroutine
+    def get(self):
+        # Ensure that the flush callback is run whether or not there
+        # was any output.  The gen.Task and direct yield forms are
+        # equivalent.
+        yield self.flush()  # "empty" flush, but writes headers
+        yield self.flush()  # empty flush
+        self.write("o")
+        yield self.flush()  # flushes the "o"
+        yield self.flush()  # empty flush
+        self.finish("k")
+
+
+class HeaderInjectionHandler(RequestHandler):
+    def get(self):
+        try:
+            self.set_header("X-Foo", "foo\r\nX-Bar: baz")
+            raise Exception("Didn't get expected exception")
+        except ValueError as e:
+            if "Unsafe header value" in str(e):
+                self.finish(b"ok")
+            else:
+                raise
+
+
+class GetArgumentHandler(RequestHandler):
+    def prepare(self):
+        if self.get_argument("source", None) == "query":
+            method = self.get_query_argument
+        elif self.get_argument("source", None) == "body":
+            method = self.get_body_argument
+        else:
+            method = self.get_argument  # type: ignore
+        self.finish(method("foo", "default"))
+
+
+class GetArgumentsHandler(RequestHandler):
+    def prepare(self):
+        self.finish(
+            dict(
+                default=self.get_arguments("foo"),
+                query=self.get_query_arguments("foo"),
+                body=self.get_body_arguments("foo"),
+            )
+        )
+
+
+# This test was shared with wsgi_test.py; now the name is meaningless.
+class WSGISafeWebTest(WebTestCase):
+    COOKIE_SECRET = "WebTest.COOKIE_SECRET"
+
+    def get_app_kwargs(self):
+        loader = DictLoader(
+            {
+                "linkify.html": "{% module linkify(message) %}",
+                "page.html": """\
+<html><head></head><body>
+{% for e in entries %}
+{% module Template("entry.html", entry=e) %}
+{% end %}
+</body></html>""",
+                "entry.html": """\
+{{ set_resources(embedded_css=".entry { margin-bottom: 1em; }",
+                 embedded_javascript="js_embed()",
+                 css_files=["/base.css", "/foo.css"],
+                 javascript_files="/common.js",
+                 html_head="<meta>",
+                 html_body='<script src="/analytics.js"/>') }}
+<div class="entry">...</div>""",
+            }
+        )
+        return dict(
+            template_loader=loader,
+            autoescape="xhtml_escape",
+            cookie_secret=self.COOKIE_SECRET,
+        )
+
+    def tearDown(self):
+        super().tearDown()
+        RequestHandler._template_loaders.clear()
+
+    def get_handlers(self):
+        urls = [
+            url("/typecheck/(.*)", TypeCheckHandler, name="typecheck"),
+            url("/decode_arg/(.*)", DecodeArgHandler, name="decode_arg"),
+            url("/decode_arg_kw/(?P<arg>.*)", DecodeArgHandler),
+            url("/linkify", LinkifyHandler),
+            url("/uimodule_resources", UIModuleResourceHandler),
+            url("/optional_path/(.+)?", OptionalPathHandler),
+            url("/multi_header", MultiHeaderHandler),
+            url("/redirect", RedirectHandler),
+            url(
+                "/web_redirect_permanent",
+                WebRedirectHandler,
+                {"url": "/web_redirect_newpath"},
+            ),
+            url(
+                "/web_redirect",
+                WebRedirectHandler,
+                {"url": "/web_redirect_newpath", "permanent": False},
+            ),
+            url(
+                "//web_redirect_double_slash",
+                WebRedirectHandler,
+                {"url": "/web_redirect_newpath"},
+            ),
+            url("/header_injection", HeaderInjectionHandler),
+            url("/get_argument", GetArgumentHandler),
+            url("/get_arguments", GetArgumentsHandler),
+        ]
+        return urls
+
+    def fetch_json(self, *args, **kwargs):
+        response = self.fetch(*args, **kwargs)
+        response.rethrow()
+        return json_decode(response.body)
+
+    def test_types(self):
+        cookie_value = to_unicode(
+            create_signed_value(self.COOKIE_SECRET, "asdf", "qwer")
+        )
+        response = self.fetch(
+            "/typecheck/asdf?foo=bar", headers={"Cookie": "asdf=" + cookie_value}
+        )
+        data = json_decode(response.body)
+        self.assertEqual(data, {})
+
+        response = self.fetch(
+            "/typecheck/asdf?foo=bar",
+            method="POST",
+            headers={"Cookie": "asdf=" + cookie_value},
+            body="foo=bar",
+        )
+
+    def test_decode_argument(self):
+        # These urls all decode to the same thing
+        urls = [
+            "/decode_arg/%C3%A9?foo=%C3%A9&encoding=utf-8",
+            "/decode_arg/%E9?foo=%E9&encoding=latin1",
+            "/decode_arg_kw/%E9?foo=%E9&encoding=latin1",
+        ]
+        for req_url in urls:
+            response = self.fetch(req_url)
+            response.rethrow()
+            data = json_decode(response.body)
+            self.assertEqual(
+                data,
+                {"path": ["unicode", "\u00e9"], "query": ["unicode", "\u00e9"]},
+            )
+
+        response = self.fetch("/decode_arg/%C3%A9?foo=%C3%A9")
+        response.rethrow()
+        data = json_decode(response.body)
+        self.assertEqual(data, {"path": ["bytes", "c3a9"], "query": ["bytes", "c3a9"]})
+
+    def test_decode_argument_invalid_unicode(self):
+        # test that invalid unicode in URLs causes 400, not 500
+        with ExpectLog(gen_log, ".*Invalid unicode.*"):
+            response = self.fetch("/typecheck/invalid%FF")
+            self.assertEqual(response.code, 400)
+            response = self.fetch("/typecheck/invalid?foo=%FF")
+            self.assertEqual(response.code, 400)
+
+    def test_decode_argument_plus(self):
+        # These urls are all equivalent.
+        urls = [
+            "/decode_arg/1%20%2B%201?foo=1%20%2B%201&encoding=utf-8",
+            "/decode_arg/1%20+%201?foo=1+%2B+1&encoding=utf-8",
+        ]
+        for req_url in urls:
+            response = self.fetch(req_url)
+            response.rethrow()
+            data = json_decode(response.body)
+            self.assertEqual(
+                data,
+                {"path": ["unicode", "1 + 1"], "query": ["unicode", "1 + 1"]},
+            )
+
+    def test_reverse_url(self):
+        self.assertEqual(self.app.reverse_url("decode_arg", "foo"), "/decode_arg/foo")
+        self.assertEqual(self.app.reverse_url("decode_arg", 42), "/decode_arg/42")
+        self.assertEqual(self.app.reverse_url("decode_arg", b"\xe9"), "/decode_arg/%E9")
+        self.assertEqual(
+            self.app.reverse_url("decode_arg", "\u00e9"), "/decode_arg/%C3%A9"
+        )
+        self.assertEqual(
+            self.app.reverse_url("decode_arg", "1 + 1"), "/decode_arg/1%20%2B%201"
+        )
+
+    def test_uimodule_unescaped(self):
+        response = self.fetch("/linkify")
+        self.assertEqual(
+            response.body, b'<a href="http://example.com">http://example.com</a>'
+        )
+
+    def test_uimodule_resources(self):
+        response = self.fetch("/uimodule_resources")
+        self.assertEqual(
+            response.body,
+            b"""\
+<html><head><link href="/base.css" type="text/css" rel="stylesheet"/><link href="/foo.css" type="text/css" rel="stylesheet"/>
+<style type="text/css">
+.entry { margin-bottom: 1em; }
+</style>
+<meta>
+</head><body>
+
+
+<div class="entry">...</div>
+
+
+<div class="entry">...</div>
+
+<script src="/common.js" type="text/javascript"></script>
+<script type="text/javascript">
+//<![CDATA[
+js_embed()
+//]]>
+</script>
+<script src="/analytics.js"/>
+</body></html>""",  # noqa: E501
+        )
+
+    def test_optional_path(self):
+        self.assertEqual(self.fetch_json("/optional_path/foo"), {"path": "foo"})
+        self.assertEqual(self.fetch_json("/optional_path/"), {"path": None})
+
+    def test_multi_header(self):
+        response = self.fetch("/multi_header")
+        self.assertEqual(response.headers["x-overwrite"], "2")
+        self.assertEqual(response.headers.get_list("x-multi"), ["3", "4"])
+
+    def test_redirect(self):
+        response = self.fetch("/redirect?permanent=1", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        response = self.fetch("/redirect?permanent=0", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        response = self.fetch("/redirect?status=307", follow_redirects=False)
+        self.assertEqual(response.code, 307)
+
+    def test_web_redirect(self):
+        response = self.fetch("/web_redirect_permanent", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/web_redirect_newpath")
+        response = self.fetch("/web_redirect", follow_redirects=False)
+        self.assertEqual(response.code, 302)
+        self.assertEqual(response.headers["Location"], "/web_redirect_newpath")
+
+    def test_web_redirect_double_slash(self):
+        response = self.fetch("//web_redirect_double_slash", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/web_redirect_newpath")
+
+    def test_header_injection(self):
+        response = self.fetch("/header_injection")
+        self.assertEqual(response.body, b"ok")
+
+    def test_get_argument(self):
+        response = self.fetch("/get_argument?foo=bar")
+        self.assertEqual(response.body, b"bar")
+        response = self.fetch("/get_argument?foo=")
+        self.assertEqual(response.body, b"")
+        response = self.fetch("/get_argument")
+        self.assertEqual(response.body, b"default")
+
+        # Test merging of query and body arguments.
+        # In singular form, body arguments take precedence over query arguments.
+        body = urllib.parse.urlencode(dict(foo="hello"))
+        response = self.fetch("/get_argument?foo=bar", method="POST", body=body)
+        self.assertEqual(response.body, b"hello")
+        # In plural methods they are merged.
+        response = self.fetch("/get_arguments?foo=bar", method="POST", body=body)
+        self.assertEqual(
+            json_decode(response.body),
+            dict(default=["bar", "hello"], query=["bar"], body=["hello"]),
+        )
+
+    def test_get_query_arguments(self):
+        # send as a post so we can ensure the separation between query
+        # string and body arguments.
+        body = urllib.parse.urlencode(dict(foo="hello"))
+        response = self.fetch(
+            "/get_argument?source=query&foo=bar", method="POST", body=body
+        )
+        self.assertEqual(response.body, b"bar")
+        response = self.fetch(
+            "/get_argument?source=query&foo=", method="POST", body=body
+        )
+        self.assertEqual(response.body, b"")
+        response = self.fetch("/get_argument?source=query", method="POST", body=body)
+        self.assertEqual(response.body, b"default")
+
+    def test_get_body_arguments(self):
+        body = urllib.parse.urlencode(dict(foo="bar"))
+        response = self.fetch(
+            "/get_argument?source=body&foo=hello", method="POST", body=body
+        )
+        self.assertEqual(response.body, b"bar")
+
+        body = urllib.parse.urlencode(dict(foo=""))
+        response = self.fetch(
+            "/get_argument?source=body&foo=hello", method="POST", body=body
+        )
+        self.assertEqual(response.body, b"")
+
+        body = urllib.parse.urlencode(dict())
+        response = self.fetch(
+            "/get_argument?source=body&foo=hello", method="POST", body=body
+        )
+        self.assertEqual(response.body, b"default")
+
+    def test_no_gzip(self):
+        response = self.fetch("/get_argument")
+        self.assertNotIn("Accept-Encoding", response.headers.get("Vary", ""))
+        self.assertNotIn("gzip", response.headers.get("Content-Encoding", ""))
+
+
+class NonWSGIWebTests(WebTestCase):
+    def get_handlers(self):
+        return [("/empty_flush", EmptyFlushCallbackHandler)]
+
+    def test_empty_flush(self):
+        response = self.fetch("/empty_flush")
+        self.assertEqual(response.body, b"ok")
+
+
+class ErrorResponseTest(WebTestCase):
+    def get_handlers(self):
+        class DefaultHandler(RequestHandler):
+            def get(self):
+                if self.get_argument("status", None):
+                    raise HTTPError(int(self.get_argument("status")))
+                1 / 0
+
+        class WriteErrorHandler(RequestHandler):
+            def get(self):
+                if self.get_argument("status", None):
+                    self.send_error(int(self.get_argument("status")))
+                else:
+                    1 / 0
+
+            def write_error(self, status_code, **kwargs):
+                self.set_header("Content-Type", "text/plain")
+                if "exc_info" in kwargs:
+                    self.write("Exception: %s" % kwargs["exc_info"][0].__name__)
+                else:
+                    self.write("Status: %d" % status_code)
+
+        class FailedWriteErrorHandler(RequestHandler):
+            def get(self):
+                1 / 0
+
+            def write_error(self, status_code, **kwargs):
+                raise Exception("exception in write_error")
+
+        return [
+            url("/default", DefaultHandler),
+            url("/write_error", WriteErrorHandler),
+            url("/failed_write_error", FailedWriteErrorHandler),
+        ]
+
+    def test_default(self):
+        with ExpectLog(app_log, "Uncaught exception"):
+            response = self.fetch("/default")
+            self.assertEqual(response.code, 500)
+            self.assertTrue(b"500: Internal Server Error" in response.body)
+
+            response = self.fetch("/default?status=503")
+            self.assertEqual(response.code, 503)
+            self.assertTrue(b"503: Service Unavailable" in response.body)
+
+            response = self.fetch("/default?status=435")
+            self.assertEqual(response.code, 435)
+            self.assertTrue(b"435: Unknown" in response.body)
+
+    def test_write_error(self):
+        with ExpectLog(app_log, "Uncaught exception"):
+            response = self.fetch("/write_error")
+            self.assertEqual(response.code, 500)
+            self.assertEqual(b"Exception: ZeroDivisionError", response.body)
+
+            response = self.fetch("/write_error?status=503")
+            self.assertEqual(response.code, 503)
+            self.assertEqual(b"Status: 503", response.body)
+
+    def test_failed_write_error(self):
+        with ExpectLog(app_log, "Uncaught exception"):
+            response = self.fetch("/failed_write_error")
+            self.assertEqual(response.code, 500)
+            self.assertEqual(b"", response.body)
+
+
+class StaticFileTest(WebTestCase):
+    # The expected SHA-512 hash of robots.txt, used in tests that call
+    # StaticFileHandler.get_version
+    robots_txt_hash = (
+        b"63a36e950e134b5217e33c763e88840c10a07d80e6057d92b9ac97508de7fb1f"
+        b"a6f0e9b7531e169657165ea764e8963399cb6d921ffe6078425aaafe54c04563"
+    )
+    static_dir = os.path.join(os.path.dirname(__file__), "static")
+
+    def get_handlers(self):
+        class StaticUrlHandler(RequestHandler):
+            def get(self, path):
+                with_v = int(self.get_argument("include_version", "1"))
+                self.write(self.static_url(path, include_version=with_v))
+
+        class AbsoluteStaticUrlHandler(StaticUrlHandler):
+            include_host = True
+
+        class OverrideStaticUrlHandler(RequestHandler):
+            def get(self, path):
+                do_include = bool(self.get_argument("include_host"))
+                self.include_host = not do_include
+
+                regular_url = self.static_url(path)
+                override_url = self.static_url(path, include_host=do_include)
+                if override_url == regular_url:
+                    return self.write(str(False))
+
+                protocol = self.request.protocol + "://"
+                protocol_length = len(protocol)
+                check_regular = regular_url.find(protocol, 0, protocol_length)
+                check_override = override_url.find(protocol, 0, protocol_length)
+
+                if do_include:
+                    result = check_override == 0 and check_regular == -1
+                else:
+                    result = check_override == -1 and check_regular == 0
+                self.write(str(result))
+
+        return [
+            ("/static_url/(.*)", StaticUrlHandler),
+            ("/abs_static_url/(.*)", AbsoluteStaticUrlHandler),
+            ("/override_static_url/(.*)", OverrideStaticUrlHandler),
+            ("/root_static/(.*)", StaticFileHandler, dict(path="/")),
+        ]
+
+    def get_app_kwargs(self):
+        return dict(static_path=relpath("static"))
+
+    def test_static_files(self):
+        response = self.fetch("/robots.txt")
+        self.assertTrue(b"Disallow: /" in response.body)
+
+        response = self.fetch("/static/robots.txt")
+        self.assertTrue(b"Disallow: /" in response.body)
+        self.assertEqual(response.headers.get("Content-Type"), "text/plain")
+
+    def test_static_compressed_files(self):
+        response = self.fetch("/static/sample.xml.gz")
+        self.assertEqual(response.headers.get("Content-Type"), "application/gzip")
+        response = self.fetch("/static/sample.xml.bz2")
+        self.assertEqual(
+            response.headers.get("Content-Type"), "application/octet-stream"
+        )
+        # make sure the uncompressed file still has the correct type
+        response = self.fetch("/static/sample.xml")
+        self.assertTrue(
+            response.headers.get("Content-Type") in set(("text/xml", "application/xml"))
+        )
+
+    def test_static_url(self):
+        response = self.fetch("/static_url/robots.txt")
+        self.assertEqual(response.body, b"/static/robots.txt?v=" + self.robots_txt_hash)
+
+    def test_absolute_static_url(self):
+        response = self.fetch("/abs_static_url/robots.txt")
+        self.assertEqual(
+            response.body,
+            (utf8(self.get_url("/")) + b"static/robots.txt?v=" + self.robots_txt_hash),
+        )
+
+    def test_relative_version_exclusion(self):
+        response = self.fetch("/static_url/robots.txt?include_version=0")
+        self.assertEqual(response.body, b"/static/robots.txt")
+
+    def test_absolute_version_exclusion(self):
+        response = self.fetch("/abs_static_url/robots.txt?include_version=0")
+        self.assertEqual(response.body, utf8(self.get_url("/") + "static/robots.txt"))
+
+    def test_include_host_override(self):
+        self._trigger_include_host_check(False)
+        self._trigger_include_host_check(True)
+
+    def _trigger_include_host_check(self, include_host):
+        path = "/override_static_url/robots.txt?include_host=%s"
+        response = self.fetch(path % int(include_host))
+        self.assertEqual(response.body, utf8(str(True)))
+
+    def get_and_head(self, *args, **kwargs):
+        """Performs a GET and HEAD request and returns the GET response.
+
+        Fails if any ``Content-*`` headers returned by the two requests
+        differ.
+        """
+        head_response = self.fetch(*args, method="HEAD", **kwargs)
+        get_response = self.fetch(*args, method="GET", **kwargs)
+        content_headers = set()
+        for h in itertools.chain(head_response.headers, get_response.headers):
+            if h.startswith("Content-"):
+                content_headers.add(h)
+        for h in content_headers:
+            self.assertEqual(
+                head_response.headers.get(h),
+                get_response.headers.get(h),
+                "%s differs between GET (%s) and HEAD (%s)"
+                % (h, head_response.headers.get(h), get_response.headers.get(h)),
+            )
+        return get_response
+
+    def test_static_304_if_modified_since(self):
+        response1 = self.get_and_head("/static/robots.txt")
+        response2 = self.get_and_head(
+            "/static/robots.txt",
+            headers={"If-Modified-Since": response1.headers["Last-Modified"]},
+        )
+        self.assertEqual(response2.code, 304)
+        self.assertTrue("Content-Length" not in response2.headers)
+
+    def test_static_304_if_none_match(self):
+        response1 = self.get_and_head("/static/robots.txt")
+        response2 = self.get_and_head(
+            "/static/robots.txt", headers={"If-None-Match": response1.headers["Etag"]}
+        )
+        self.assertEqual(response2.code, 304)
+
+    def test_static_304_etag_modified_bug(self):
+        response1 = self.get_and_head("/static/robots.txt")
+        response2 = self.get_and_head(
+            "/static/robots.txt",
+            headers={
+                "If-None-Match": '"MISMATCH"',
+                "If-Modified-Since": response1.headers["Last-Modified"],
+            },
+        )
+        self.assertEqual(response2.code, 200)
+
+    def test_static_if_modified_since_pre_epoch(self):
+        # On windows, the functions that work with time_t do not accept
+        # negative values, and at least one client (processing.js) seems
+        # to use if-modified-since 1/1/1960 as a cache-busting technique.
+        response = self.get_and_head(
+            "/static/robots.txt",
+            headers={"If-Modified-Since": "Fri, 01 Jan 1960 00:00:00 GMT"},
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_static_if_modified_since_time_zone(self):
+        # Instead of the value from Last-Modified, make requests with times
+        # chosen just before and after the known modification time
+        # of the file to ensure that the right time zone is being used
+        # when parsing If-Modified-Since.
+        stat = os.stat(relpath("static/robots.txt"))
+
+        response = self.get_and_head(
+            "/static/robots.txt",
+            headers={"If-Modified-Since": format_timestamp(stat.st_mtime - 1)},
+        )
+        self.assertEqual(response.code, 200)
+        response = self.get_and_head(
+            "/static/robots.txt",
+            headers={"If-Modified-Since": format_timestamp(stat.st_mtime + 1)},
+        )
+        self.assertEqual(response.code, 304)
+
+    def test_static_etag(self):
+        response = self.get_and_head("/static/robots.txt")
+        self.assertEqual(
+            utf8(response.headers.get("Etag")), b'"' + self.robots_txt_hash + b'"'
+        )
+
+    def test_static_with_range(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=0-9"}
+        )
+        self.assertEqual(response.code, 206)
+        self.assertEqual(response.body, b"User-agent")
+        self.assertEqual(
+            utf8(response.headers.get("Etag")), b'"' + self.robots_txt_hash + b'"'
+        )
+        self.assertEqual(response.headers.get("Content-Length"), "10")
+        self.assertEqual(response.headers.get("Content-Range"), "bytes 0-9/26")
+
+    def test_static_with_range_full_file(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=0-"}
+        )
+        # Note: Chrome refuses to play audio if it gets an HTTP 206 in response
+        # to ``Range: bytes=0-`` :(
+        self.assertEqual(response.code, 200)
+        robots_file_path = os.path.join(self.static_dir, "robots.txt")
+        with open(robots_file_path) as f:
+            self.assertEqual(response.body, utf8(f.read()))
+        self.assertEqual(response.headers.get("Content-Length"), "26")
+        self.assertEqual(response.headers.get("Content-Range"), None)
+
+    def test_static_with_range_full_past_end(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=0-10000000"}
+        )
+        self.assertEqual(response.code, 200)
+        robots_file_path = os.path.join(self.static_dir, "robots.txt")
+        with open(robots_file_path) as f:
+            self.assertEqual(response.body, utf8(f.read()))
+        self.assertEqual(response.headers.get("Content-Length"), "26")
+        self.assertEqual(response.headers.get("Content-Range"), None)
+
+    def test_static_with_range_partial_past_end(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=1-10000000"}
+        )
+        self.assertEqual(response.code, 206)
+        robots_file_path = os.path.join(self.static_dir, "robots.txt")
+        with open(robots_file_path) as f:
+            self.assertEqual(response.body, utf8(f.read()[1:]))
+        self.assertEqual(response.headers.get("Content-Length"), "25")
+        self.assertEqual(response.headers.get("Content-Range"), "bytes 1-25/26")
+
+    def test_static_with_range_end_edge(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=22-"}
+        )
+        self.assertEqual(response.body, b": /\n")
+        self.assertEqual(response.headers.get("Content-Length"), "4")
+        self.assertEqual(response.headers.get("Content-Range"), "bytes 22-25/26")
+
+    def test_static_with_range_neg_end(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=-4"}
+        )
+        self.assertEqual(response.body, b": /\n")
+        self.assertEqual(response.headers.get("Content-Length"), "4")
+        self.assertEqual(response.headers.get("Content-Range"), "bytes 22-25/26")
+
+    def test_static_with_range_neg_past_start(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=-1000000"}
+        )
+        self.assertEqual(response.code, 200)
+        robots_file_path = os.path.join(self.static_dir, "robots.txt")
+        with open(robots_file_path) as f:
+            self.assertEqual(response.body, utf8(f.read()))
+        self.assertEqual(response.headers.get("Content-Length"), "26")
+        self.assertEqual(response.headers.get("Content-Range"), None)
+
+    def test_static_invalid_range(self):
+        response = self.get_and_head("/static/robots.txt", headers={"Range": "asdf"})
+        self.assertEqual(response.code, 200)
+
+    def test_static_unsatisfiable_range_zero_suffix(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=-0"}
+        )
+        self.assertEqual(response.headers.get("Content-Range"), "bytes */26")
+        self.assertEqual(response.code, 416)
+
+    def test_static_unsatisfiable_range_invalid_start(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=26"}
+        )
+        self.assertEqual(response.code, 416)
+        self.assertEqual(response.headers.get("Content-Range"), "bytes */26")
+
+    def test_static_unsatisfiable_range_end_less_than_start(self):
+        response = self.get_and_head(
+            "/static/robots.txt", headers={"Range": "bytes=10-3"}
+        )
+        self.assertEqual(response.code, 416)
+        self.assertEqual(response.headers.get("Content-Range"), "bytes */26")
+
+    def test_static_head(self):
+        response = self.fetch("/static/robots.txt", method="HEAD")
+        self.assertEqual(response.code, 200)
+        # No body was returned, but we did get the right content length.
+        self.assertEqual(response.body, b"")
+        self.assertEqual(response.headers["Content-Length"], "26")
+        self.assertEqual(
+            utf8(response.headers["Etag"]), b'"' + self.robots_txt_hash + b'"'
+        )
+
+    def test_static_head_range(self):
+        response = self.fetch(
+            "/static/robots.txt", method="HEAD", headers={"Range": "bytes=1-4"}
+        )
+        self.assertEqual(response.code, 206)
+        self.assertEqual(response.body, b"")
+        self.assertEqual(response.headers["Content-Length"], "4")
+        self.assertEqual(
+            utf8(response.headers["Etag"]), b'"' + self.robots_txt_hash + b'"'
+        )
+
+    def test_static_range_if_none_match(self):
+        response = self.get_and_head(
+            "/static/robots.txt",
+            headers={
+                "Range": "bytes=1-4",
+                "If-None-Match": b'"' + self.robots_txt_hash + b'"',
+            },
+        )
+        self.assertEqual(response.code, 304)
+        self.assertEqual(response.body, b"")
+        self.assertTrue("Content-Length" not in response.headers)
+        self.assertEqual(
+            utf8(response.headers["Etag"]), b'"' + self.robots_txt_hash + b'"'
+        )
+
+    def test_static_404(self):
+        response = self.get_and_head("/static/blarg")
+        self.assertEqual(response.code, 404)
+
+    def test_path_traversal_protection(self):
+        # curl_httpclient processes ".." on the client side, so we
+        # must test this with simple_httpclient.
+        self.http_client.close()
+        self.http_client = SimpleAsyncHTTPClient()
+        with ExpectLog(gen_log, ".*not in root static directory"):
+            response = self.get_and_head("/static/../static_foo.txt")
+        # Attempted path traversal should result in 403, not 200
+        # (which means the check failed and the file was served)
+        # or 404 (which means that the file didn't exist and
+        # is probably a packaging error).
+        self.assertEqual(response.code, 403)
+
+    @unittest.skipIf(os.name != "posix", "non-posix OS")
+    def test_root_static_path(self):
+        # Sometimes people set the StaticFileHandler's path to '/'
+        # to disable Tornado's path validation (in conjunction with
+        # their own validation in get_absolute_path). Make sure
+        # that the stricter validation in 4.2.1 doesn't break them.
+        path = os.path.join(
+            os.path.dirname(os.path.abspath(__file__)), "static/robots.txt"
+        )
+        response = self.get_and_head("/root_static" + urllib.parse.quote(path))
+        self.assertEqual(response.code, 200)
+
+
+class StaticDefaultFilenameTest(WebTestCase):
+    def get_app_kwargs(self):
+        return dict(
+            static_path=relpath("static"),
+            static_handler_args=dict(default_filename="index.html"),
+        )
+
+    def get_handlers(self):
+        return []
+
+    def test_static_default_filename(self):
+        response = self.fetch("/static/dir/", follow_redirects=False)
+        self.assertEqual(response.code, 200)
+        self.assertEqual(b"this is the index\n", response.body)
+
+    def test_static_default_redirect(self):
+        response = self.fetch("/static/dir", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertTrue(response.headers["Location"].endswith("/static/dir/"))
+
+
+class StaticFileWithPathTest(WebTestCase):
+    def get_app_kwargs(self):
+        return dict(
+            static_path=relpath("static"),
+            static_handler_args=dict(default_filename="index.html"),
+        )
+
+    def get_handlers(self):
+        return [("/foo/(.*)", StaticFileHandler, {"path": relpath("templates/")})]
+
+    def test_serve(self):
+        response = self.fetch("/foo/utf8.html")
+        self.assertEqual(response.body, b"H\xc3\xa9llo\n")
+
+
+class CustomStaticFileTest(WebTestCase):
+    def get_handlers(self):
+        class MyStaticFileHandler(StaticFileHandler):
+            @classmethod
+            def make_static_url(cls, settings, path):
+                version_hash = cls.get_version(settings, path)
+                extension_index = path.rindex(".")
+                before_version = path[:extension_index]
+                after_version = path[(extension_index + 1) :]
+                return "/static/%s.%s.%s" % (
+                    before_version,
+                    version_hash,
+                    after_version,
+                )
+
+            def parse_url_path(self, url_path):
+                extension_index = url_path.rindex(".")
+                version_index = url_path.rindex(".", 0, extension_index)
+                return "%s%s" % (url_path[:version_index], url_path[extension_index:])
+
+            @classmethod
+            def get_absolute_path(cls, settings, path):
+                return "CustomStaticFileTest:" + path
+
+            def validate_absolute_path(self, root, absolute_path):
+                return absolute_path
+
+            @classmethod
+            def get_content(self, path, start=None, end=None):
+                assert start is None and end is None
+                if path == "CustomStaticFileTest:foo.txt":
+                    return b"bar"
+                raise Exception("unexpected path %r" % path)
+
+            def get_content_size(self):
+                if self.absolute_path == "CustomStaticFileTest:foo.txt":
+                    return 3
+                raise Exception("unexpected path %r" % self.absolute_path)
+
+            def get_modified_time(self):
+                return None
+
+            @classmethod
+            def get_version(cls, settings, path):
+                return "42"
+
+        class StaticUrlHandler(RequestHandler):
+            def get(self, path):
+                self.write(self.static_url(path))
+
+        self.static_handler_class = MyStaticFileHandler
+
+        return [("/static_url/(.*)", StaticUrlHandler)]
+
+    def get_app_kwargs(self):
+        return dict(static_path="dummy", static_handler_class=self.static_handler_class)
+
+    def test_serve(self):
+        response = self.fetch("/static/foo.42.txt")
+        self.assertEqual(response.body, b"bar")
+
+    def test_static_url(self):
+        with ExpectLog(gen_log, "Could not open static file", required=False):
+            response = self.fetch("/static_url/foo.txt")
+            self.assertEqual(response.body, b"/static/foo.42.txt")
+
+
+class HostMatchingTest(WebTestCase):
+    class Handler(RequestHandler):
+        def initialize(self, reply):
+            self.reply = reply
+
+        def get(self):
+            self.write(self.reply)
+
+    def get_handlers(self):
+        return [("/foo", HostMatchingTest.Handler, {"reply": "wildcard"})]
+
+    def test_host_matching(self):
+        self.app.add_handlers(
+            "www.example.com", [("/foo", HostMatchingTest.Handler, {"reply": "[0]"})]
+        )
+        self.app.add_handlers(
+            r"www\.example\.com", [("/bar", HostMatchingTest.Handler, {"reply": "[1]"})]
+        )
+        self.app.add_handlers(
+            "www.example.com", [("/baz", HostMatchingTest.Handler, {"reply": "[2]"})]
+        )
+        self.app.add_handlers(
+            "www.e.*e.com", [("/baz", HostMatchingTest.Handler, {"reply": "[3]"})]
+        )
+
+        response = self.fetch("/foo")
+        self.assertEqual(response.body, b"wildcard")
+        response = self.fetch("/bar")
+        self.assertEqual(response.code, 404)
+        response = self.fetch("/baz")
+        self.assertEqual(response.code, 404)
+
+        response = self.fetch("/foo", headers={"Host": "www.example.com"})
+        self.assertEqual(response.body, b"[0]")
+        response = self.fetch("/bar", headers={"Host": "www.example.com"})
+        self.assertEqual(response.body, b"[1]")
+        response = self.fetch("/baz", headers={"Host": "www.example.com"})
+        self.assertEqual(response.body, b"[2]")
+        response = self.fetch("/baz", headers={"Host": "www.exe.com"})
+        self.assertEqual(response.body, b"[3]")
+
+
+class DefaultHostMatchingTest(WebTestCase):
+    def get_handlers(self):
+        return []
+
+    def get_app_kwargs(self):
+        return {"default_host": "www.example.com"}
+
+    def test_default_host_matching(self):
+        self.app.add_handlers(
+            "www.example.com", [("/foo", HostMatchingTest.Handler, {"reply": "[0]"})]
+        )
+        self.app.add_handlers(
+            r"www\.example\.com", [("/bar", HostMatchingTest.Handler, {"reply": "[1]"})]
+        )
+        self.app.add_handlers(
+            "www.test.com", [("/baz", HostMatchingTest.Handler, {"reply": "[2]"})]
+        )
+
+        response = self.fetch("/foo")
+        self.assertEqual(response.body, b"[0]")
+        response = self.fetch("/bar")
+        self.assertEqual(response.body, b"[1]")
+        response = self.fetch("/baz")
+        self.assertEqual(response.code, 404)
+
+        response = self.fetch("/foo", headers={"X-Real-Ip": "127.0.0.1"})
+        self.assertEqual(response.code, 404)
+
+        self.app.default_host = "www.test.com"
+
+        response = self.fetch("/baz")
+        self.assertEqual(response.body, b"[2]")
+
+
+class NamedURLSpecGroupsTest(WebTestCase):
+    def get_handlers(self):
+        class EchoHandler(RequestHandler):
+            def get(self, path):
+                self.write(path)
+
+        return [
+            ("/str/(?P<path>.*)", EchoHandler),
+            ("/unicode/(?P<path>.*)", EchoHandler),
+        ]
+
+    def test_named_urlspec_groups(self):
+        response = self.fetch("/str/foo")
+        self.assertEqual(response.body, b"foo")
+
+        response = self.fetch("/unicode/bar")
+        self.assertEqual(response.body, b"bar")
+
+
+class ClearHeaderTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.set_header("h1", "foo")
+            self.set_header("h2", "bar")
+            self.clear_header("h1")
+            self.clear_header("nonexistent")
+
+    def test_clear_header(self):
+        response = self.fetch("/")
+        self.assertTrue("h1" not in response.headers)
+        self.assertEqual(response.headers["h2"], "bar")
+
+
+class Header204Test(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.set_status(204)
+            self.finish()
+
+    def test_204_headers(self):
+        response = self.fetch("/")
+        self.assertEqual(response.code, 204)
+        self.assertNotIn("Content-Length", response.headers)
+        self.assertNotIn("Transfer-Encoding", response.headers)
+
+
+class Header304Test(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.set_header("Content-Language", "en_US")
+            self.write("hello")
+
+    def test_304_headers(self):
+        response1 = self.fetch("/")
+        self.assertEqual(response1.headers["Content-Length"], "5")
+        self.assertEqual(response1.headers["Content-Language"], "en_US")
+
+        response2 = self.fetch(
+            "/", headers={"If-None-Match": response1.headers["Etag"]}
+        )
+        self.assertEqual(response2.code, 304)
+        self.assertTrue("Content-Length" not in response2.headers)
+        self.assertTrue("Content-Language" not in response2.headers)
+        # Not an entity header, but should not be added to 304s by chunking
+        self.assertTrue("Transfer-Encoding" not in response2.headers)
+
+
+class StatusReasonTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            reason = self.request.arguments.get("reason", [])
+            self.set_status(
+                int(self.get_argument("code")),
+                reason=to_unicode(reason[0]) if reason else None,
+            )
+
+    def get_http_client(self):
+        # simple_httpclient only: curl doesn't expose the reason string
+        return SimpleAsyncHTTPClient()
+
+    def test_status(self):
+        response = self.fetch("/?code=304")
+        self.assertEqual(response.code, 304)
+        self.assertEqual(response.reason, "Not Modified")
+        response = self.fetch("/?code=304&reason=Foo")
+        self.assertEqual(response.code, 304)
+        self.assertEqual(response.reason, "Foo")
+        response = self.fetch("/?code=682&reason=Bar")
+        self.assertEqual(response.code, 682)
+        self.assertEqual(response.reason, "Bar")
+        response = self.fetch("/?code=682")
+        self.assertEqual(response.code, 682)
+        self.assertEqual(response.reason, "Unknown")
+
+
+class DateHeaderTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.write("hello")
+
+    def test_date_header(self):
+        response = self.fetch("/")
+        parsed = email.utils.parsedate(response.headers["Date"])
+        assert parsed is not None
+        header_date = datetime.datetime(*parsed[:6])
+        self.assertTrue(
+            header_date - datetime.datetime.utcnow() < datetime.timedelta(seconds=2)
+        )
+
+
+class RaiseWithReasonTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            raise HTTPError(682, reason="Foo")
+
+    def get_http_client(self):
+        # simple_httpclient only: curl doesn't expose the reason string
+        return SimpleAsyncHTTPClient()
+
+    def test_raise_with_reason(self):
+        response = self.fetch("/")
+        self.assertEqual(response.code, 682)
+        self.assertEqual(response.reason, "Foo")
+        self.assertIn(b"682: Foo", response.body)
+
+    def test_httperror_str(self):
+        self.assertEqual(str(HTTPError(682, reason="Foo")), "HTTP 682: Foo")
+
+    def test_httperror_str_from_httputil(self):
+        self.assertEqual(str(HTTPError(682)), "HTTP 682: Unknown")
+
+
+class ErrorHandlerXSRFTest(WebTestCase):
+    def get_handlers(self):
+        # note that if the handlers list is empty we get the default_host
+        # redirect fallback instead of a 404, so test with both an
+        # explicitly defined error handler and an implicit 404.
+        return [("/error", ErrorHandler, dict(status_code=417))]
+
+    def get_app_kwargs(self):
+        return dict(xsrf_cookies=True)
+
+    def test_error_xsrf(self):
+        response = self.fetch("/error", method="POST", body="")
+        self.assertEqual(response.code, 417)
+
+    def test_404_xsrf(self):
+        response = self.fetch("/404", method="POST", body="")
+        self.assertEqual(response.code, 404)
+
+
+class GzipTestCase(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            for v in self.get_arguments("vary"):
+                self.add_header("Vary", v)
+            # Must write at least MIN_LENGTH bytes to activate compression.
+            self.write("hello world" + ("!" * GZipContentEncoding.MIN_LENGTH))
+
+    def get_app_kwargs(self):
+        return dict(
+            gzip=True, static_path=os.path.join(os.path.dirname(__file__), "static")
+        )
+
+    def assert_compressed(self, response):
+        # simple_httpclient renames the content-encoding header;
+        # curl_httpclient doesn't.
+        self.assertEqual(
+            response.headers.get(
+                "Content-Encoding", response.headers.get("X-Consumed-Content-Encoding")
+            ),
+            "gzip",
+        )
+
+    def test_gzip(self):
+        response = self.fetch("/")
+        self.assert_compressed(response)
+        self.assertEqual(response.headers["Vary"], "Accept-Encoding")
+
+    def test_gzip_static(self):
+        # The streaming responses in StaticFileHandler have subtle
+        # interactions with the gzip output so test this case separately.
+        response = self.fetch("/robots.txt")
+        self.assert_compressed(response)
+        self.assertEqual(response.headers["Vary"], "Accept-Encoding")
+
+    def test_gzip_not_requested(self):
+        response = self.fetch("/", use_gzip=False)
+        self.assertNotIn("Content-Encoding", response.headers)
+        self.assertEqual(response.headers["Vary"], "Accept-Encoding")
+
+    def test_vary_already_present(self):
+        response = self.fetch("/?vary=Accept-Language")
+        self.assert_compressed(response)
+        self.assertEqual(
+            [s.strip() for s in response.headers["Vary"].split(",")],
+            ["Accept-Language", "Accept-Encoding"],
+        )
+
+    def test_vary_already_present_multiple(self):
+        # Regression test for https://github.com/tornadoweb/tornado/issues/1670
+        response = self.fetch("/?vary=Accept-Language&vary=Cookie")
+        self.assert_compressed(response)
+        self.assertEqual(
+            [s.strip() for s in response.headers["Vary"].split(",")],
+            ["Accept-Language", "Cookie", "Accept-Encoding"],
+        )
+
+
+class PathArgsInPrepareTest(WebTestCase):
+    class Handler(RequestHandler):
+        def prepare(self):
+            self.write(dict(args=self.path_args, kwargs=self.path_kwargs))
+
+        def get(self, path):
+            assert path == "foo"
+            self.finish()
+
+    def get_handlers(self):
+        return [("/pos/(.*)", self.Handler), ("/kw/(?P<path>.*)", self.Handler)]
+
+    def test_pos(self):
+        response = self.fetch("/pos/foo")
+        response.rethrow()
+        data = json_decode(response.body)
+        self.assertEqual(data, {"args": ["foo"], "kwargs": {}})
+
+    def test_kw(self):
+        response = self.fetch("/kw/foo")
+        response.rethrow()
+        data = json_decode(response.body)
+        self.assertEqual(data, {"args": [], "kwargs": {"path": "foo"}})
+
+
+class ClearAllCookiesTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.clear_all_cookies()
+            self.write("ok")
+
+    def test_clear_all_cookies(self):
+        response = self.fetch("/", headers={"Cookie": "foo=bar; baz=xyzzy"})
+        set_cookies = sorted(response.headers.get_list("Set-Cookie"))
+        # Python 3.5 sends 'baz="";'; older versions use 'baz=;'
+        self.assertTrue(
+            set_cookies[0].startswith("baz=;") or set_cookies[0].startswith('baz="";')
+        )
+        self.assertTrue(
+            set_cookies[1].startswith("foo=;") or set_cookies[1].startswith('foo="";')
+        )
+
+
+class PermissionError(Exception):
+    pass
+
+
+class ExceptionHandlerTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            exc = self.get_argument("exc")
+            if exc == "http":
+                raise HTTPError(410, "no longer here")
+            elif exc == "zero":
+                1 / 0
+            elif exc == "permission":
+                raise PermissionError("not allowed")
+
+        def write_error(self, status_code, **kwargs):
+            if "exc_info" in kwargs:
+                typ, value, tb = kwargs["exc_info"]
+                if isinstance(value, PermissionError):
+                    self.set_status(403)
+                    self.write("PermissionError")
+                    return
+            RequestHandler.write_error(self, status_code, **kwargs)
+
+        def log_exception(self, typ, value, tb):
+            if isinstance(value, PermissionError):
+                app_log.warning("custom logging for PermissionError: %s", value.args[0])
+            else:
+                RequestHandler.log_exception(self, typ, value, tb)
+
+    def test_http_error(self):
+        # HTTPErrors are logged as warnings with no stack trace.
+        # TODO: extend ExpectLog to test this more precisely
+        with ExpectLog(gen_log, ".*no longer here"):
+            response = self.fetch("/?exc=http")
+            self.assertEqual(response.code, 410)
+
+    def test_unknown_error(self):
+        # Unknown errors are logged as errors with a stack trace.
+        with ExpectLog(app_log, "Uncaught exception"):
+            response = self.fetch("/?exc=zero")
+            self.assertEqual(response.code, 500)
+
+    def test_known_error(self):
+        # log_exception can override logging behavior, and write_error
+        # can override the response.
+        with ExpectLog(app_log, "custom logging for PermissionError: not allowed"):
+            response = self.fetch("/?exc=permission")
+            self.assertEqual(response.code, 403)
+
+
+class BuggyLoggingTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            1 / 0
+
+        def log_exception(self, typ, value, tb):
+            1 / 0
+
+    def test_buggy_log_exception(self):
+        # Something gets logged even though the application's
+        # logger is broken.
+        with ExpectLog(app_log, ".*"):
+            self.fetch("/")
+
+
+class UIMethodUIModuleTest(SimpleHandlerTestCase):
+    """Test that UI methods and modules are created correctly and
+    associated with the handler.
+    """
+
+    class Handler(RequestHandler):
+        def get(self):
+            self.render("foo.html")
+
+        def value(self):
+            return self.get_argument("value")
+
+    def get_app_kwargs(self):
+        def my_ui_method(handler, x):
+            return "In my_ui_method(%s) with handler value %s." % (x, handler.value())
+
+        class MyModule(UIModule):
+            def render(self, x):
+                return "In MyModule(%s) with handler value %s." % (
+                    x,
+                    typing.cast(UIMethodUIModuleTest.Handler, self.handler).value(),
+                )
+
+        loader = DictLoader(
+            {"foo.html": "{{ my_ui_method(42) }} {% module MyModule(123) %}"}
+        )
+        return dict(
+            template_loader=loader,
+            ui_methods={"my_ui_method": my_ui_method},
+            ui_modules={"MyModule": MyModule},
+        )
+
+    def tearDown(self):
+        super().tearDown()
+        # TODO: fix template loader caching so this isn't necessary.
+        RequestHandler._template_loaders.clear()
+
+    def test_ui_method(self):
+        response = self.fetch("/?value=asdf")
+        self.assertEqual(
+            response.body,
+            b"In my_ui_method(42) with handler value asdf. "
+            b"In MyModule(123) with handler value asdf.",
+        )
+
+
+class GetArgumentErrorTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            try:
+                self.get_argument("foo")
+                self.write({})
+            except MissingArgumentError as e:
+                self.write({"arg_name": e.arg_name, "log_message": e.log_message})
+
+    def test_catch_error(self):
+        response = self.fetch("/")
+        self.assertEqual(
+            json_decode(response.body),
+            {"arg_name": "foo", "log_message": "Missing argument foo"},
+        )
+
+
+class SetLazyPropertiesTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def prepare(self):
+            self.current_user = "Ben"
+            self.locale = locale.get("en_US")
+
+        def get_user_locale(self):
+            raise NotImplementedError()
+
+        def get_current_user(self):
+            raise NotImplementedError()
+
+        def get(self):
+            self.write("Hello %s (%s)" % (self.current_user, self.locale.code))
+
+    def test_set_properties(self):
+        # Ensure that current_user can be assigned to normally for apps
+        # that want to forgo the lazy get_current_user property
+        response = self.fetch("/")
+        self.assertEqual(response.body, b"Hello Ben (en_US)")
+
+
+class GetCurrentUserTest(WebTestCase):
+    def get_app_kwargs(self):
+        class WithoutUserModule(UIModule):
+            def render(self):
+                return ""
+
+        class WithUserModule(UIModule):
+            def render(self):
+                return str(self.current_user)
+
+        loader = DictLoader(
+            {
+                "without_user.html": "",
+                "with_user.html": "{{ current_user }}",
+                "without_user_module.html": "{% module WithoutUserModule() %}",
+                "with_user_module.html": "{% module WithUserModule() %}",
+            }
+        )
+        return dict(
+            template_loader=loader,
+            ui_modules={
+                "WithUserModule": WithUserModule,
+                "WithoutUserModule": WithoutUserModule,
+            },
+        )
+
+    def tearDown(self):
+        super().tearDown()
+        RequestHandler._template_loaders.clear()
+
+    def get_handlers(self):
+        class CurrentUserHandler(RequestHandler):
+            def prepare(self):
+                self.has_loaded_current_user = False
+
+            def get_current_user(self):
+                self.has_loaded_current_user = True
+                return ""
+
+        class WithoutUserHandler(CurrentUserHandler):
+            def get(self):
+                self.render_string("without_user.html")
+                self.finish(str(self.has_loaded_current_user))
+
+        class WithUserHandler(CurrentUserHandler):
+            def get(self):
+                self.render_string("with_user.html")
+                self.finish(str(self.has_loaded_current_user))
+
+        class CurrentUserModuleHandler(CurrentUserHandler):
+            def get_template_namespace(self):
+                # If RequestHandler.get_template_namespace is called, then
+                # get_current_user is evaluated. Until #820 is fixed, this
+                # is a small hack to circumvent the issue.
+                return self.ui
+
+        class WithoutUserModuleHandler(CurrentUserModuleHandler):
+            def get(self):
+                self.render_string("without_user_module.html")
+                self.finish(str(self.has_loaded_current_user))
+
+        class WithUserModuleHandler(CurrentUserModuleHandler):
+            def get(self):
+                self.render_string("with_user_module.html")
+                self.finish(str(self.has_loaded_current_user))
+
+        return [
+            ("/without_user", WithoutUserHandler),
+            ("/with_user", WithUserHandler),
+            ("/without_user_module", WithoutUserModuleHandler),
+            ("/with_user_module", WithUserModuleHandler),
+        ]
+
+    @unittest.skip("needs fix")
+    def test_get_current_user_is_lazy(self):
+        # TODO: Make this test pass. See #820.
+        response = self.fetch("/without_user")
+        self.assertEqual(response.body, b"False")
+
+    def test_get_current_user_works(self):
+        response = self.fetch("/with_user")
+        self.assertEqual(response.body, b"True")
+
+    def test_get_current_user_from_ui_module_is_lazy(self):
+        response = self.fetch("/without_user_module")
+        self.assertEqual(response.body, b"False")
+
+    def test_get_current_user_from_ui_module_works(self):
+        response = self.fetch("/with_user_module")
+        self.assertEqual(response.body, b"True")
+
+
+class UnimplementedHTTPMethodsTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        pass
+
+    def test_unimplemented_standard_methods(self):
+        for method in ["HEAD", "GET", "DELETE", "OPTIONS"]:
+            response = self.fetch("/", method=method)
+            self.assertEqual(response.code, 405)
+        for method in ["POST", "PUT"]:
+            response = self.fetch("/", method=method, body=b"")
+            self.assertEqual(response.code, 405)
+
+
+class UnimplementedNonStandardMethodsTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def other(self):
+            # Even though this method exists, it won't get called automatically
+            # because it is not in SUPPORTED_METHODS.
+            self.write("other")
+
+    def test_unimplemented_patch(self):
+        # PATCH is recently standardized; Tornado supports it by default
+        # but wsgiref.validate doesn't like it.
+        response = self.fetch("/", method="PATCH", body=b"")
+        self.assertEqual(response.code, 405)
+
+    def test_unimplemented_other(self):
+        response = self.fetch("/", method="OTHER", allow_nonstandard_methods=True)
+        self.assertEqual(response.code, 405)
+
+
+class AllHTTPMethodsTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def method(self):
+            assert self.request.method is not None
+            self.write(self.request.method)
+
+        get = delete = options = post = put = method  # type: ignore
+
+    def test_standard_methods(self):
+        response = self.fetch("/", method="HEAD")
+        self.assertEqual(response.body, b"")
+        for method in ["GET", "DELETE", "OPTIONS"]:
+            response = self.fetch("/", method=method)
+            self.assertEqual(response.body, utf8(method))
+        for method in ["POST", "PUT"]:
+            response = self.fetch("/", method=method, body=b"")
+            self.assertEqual(response.body, utf8(method))
+
+
+class PatchMethodTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        SUPPORTED_METHODS = RequestHandler.SUPPORTED_METHODS + (  # type: ignore
+            "OTHER",
+        )
+
+        def patch(self):
+            self.write("patch")
+
+        def other(self):
+            self.write("other")
+
+    def test_patch(self):
+        response = self.fetch("/", method="PATCH", body=b"")
+        self.assertEqual(response.body, b"patch")
+
+    def test_other(self):
+        response = self.fetch("/", method="OTHER", allow_nonstandard_methods=True)
+        self.assertEqual(response.body, b"other")
+
+
+class FinishInPrepareTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def prepare(self):
+            self.finish("done")
+
+        def get(self):
+            # It's difficult to assert for certain that a method did not
+            # or will not be called in an asynchronous context, but this
+            # will be logged noisily if it is reached.
+            raise Exception("should not reach this method")
+
+    def test_finish_in_prepare(self):
+        response = self.fetch("/")
+        self.assertEqual(response.body, b"done")
+
+
+class Default404Test(WebTestCase):
+    def get_handlers(self):
+        # If there are no handlers at all a default redirect handler gets added.
+        return [("/foo", RequestHandler)]
+
+    def test_404(self):
+        response = self.fetch("/")
+        self.assertEqual(response.code, 404)
+        self.assertEqual(
+            response.body,
+            b"<html><title>404: Not Found</title>"
+            b"<body>404: Not Found</body></html>",
+        )
+
+
+class Custom404Test(WebTestCase):
+    def get_handlers(self):
+        return [("/foo", RequestHandler)]
+
+    def get_app_kwargs(self):
+        class Custom404Handler(RequestHandler):
+            def get(self):
+                self.set_status(404)
+                self.write("custom 404 response")
+
+        return dict(default_handler_class=Custom404Handler)
+
+    def test_404(self):
+        response = self.fetch("/")
+        self.assertEqual(response.code, 404)
+        self.assertEqual(response.body, b"custom 404 response")
+
+
+class DefaultHandlerArgumentsTest(WebTestCase):
+    def get_handlers(self):
+        return [("/foo", RequestHandler)]
+
+    def get_app_kwargs(self):
+        return dict(
+            default_handler_class=ErrorHandler,
+            default_handler_args=dict(status_code=403),
+        )
+
+    def test_403(self):
+        response = self.fetch("/")
+        self.assertEqual(response.code, 403)
+
+
+class HandlerByNameTest(WebTestCase):
+    def get_handlers(self):
+        # All three are equivalent.
+        return [
+            ("/hello1", HelloHandler),
+            ("/hello2", "tornado.test.web_test.HelloHandler"),
+            url("/hello3", "tornado.test.web_test.HelloHandler"),
+        ]
+
+    def test_handler_by_name(self):
+        resp = self.fetch("/hello1")
+        self.assertEqual(resp.body, b"hello")
+        resp = self.fetch("/hello2")
+        self.assertEqual(resp.body, b"hello")
+        resp = self.fetch("/hello3")
+        self.assertEqual(resp.body, b"hello")
+
+
+class StreamingRequestBodyTest(WebTestCase):
+    def get_handlers(self):
+        @stream_request_body
+        class StreamingBodyHandler(RequestHandler):
+            def initialize(self, test):
+                self.test = test
+
+            def prepare(self):
+                self.test.prepared.set_result(None)
+
+            def data_received(self, data):
+                self.test.data.set_result(data)
+
+            def get(self):
+                self.test.finished.set_result(None)
+                self.write({})
+
+        @stream_request_body
+        class EarlyReturnHandler(RequestHandler):
+            def prepare(self):
+                # If we finish the response in prepare, it won't continue to
+                # the (non-existent) data_received.
+                raise HTTPError(401)
+
+        @stream_request_body
+        class CloseDetectionHandler(RequestHandler):
+            def initialize(self, test):
+                self.test = test
+
+            def on_connection_close(self):
+                super().on_connection_close()
+                self.test.close_future.set_result(None)
+
+        return [
+            ("/stream_body", StreamingBodyHandler, dict(test=self)),
+            ("/early_return", EarlyReturnHandler),
+            ("/close_detection", CloseDetectionHandler, dict(test=self)),
+        ]
+
+    def connect(self, url, connection_close):
+        # Use a raw connection so we can control the sending of data.
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
+        s.connect(("127.0.0.1", self.get_http_port()))
+        stream = IOStream(s)
+        stream.write(b"GET " + url + b" HTTP/1.1\r\n")
+        if connection_close:
+            stream.write(b"Connection: close\r\n")
+        stream.write(b"Transfer-Encoding: chunked\r\n\r\n")
+        return stream
+
+    @gen_test
+    def test_streaming_body(self):
+        self.prepared = Future()  # type: Future[None]
+        self.data = Future()  # type: Future[bytes]
+        self.finished = Future()  # type: Future[None]
+
+        stream = self.connect(b"/stream_body", connection_close=True)
+        yield self.prepared
+        stream.write(b"4\r\nasdf\r\n")
+        # Ensure the first chunk is received before we send the second.
+        data = yield self.data
+        self.assertEqual(data, b"asdf")
+        self.data = Future()
+        stream.write(b"4\r\nqwer\r\n")
+        data = yield self.data
+        self.assertEqual(data, b"qwer")
+        stream.write(b"0\r\n\r\n")
+        yield self.finished
+        data = yield stream.read_until_close()
+        # This would ideally use an HTTP1Connection to read the response.
+        self.assertTrue(data.endswith(b"{}"))
+        stream.close()
+
+    @gen_test
+    def test_early_return(self):
+        stream = self.connect(b"/early_return", connection_close=False)
+        data = yield stream.read_until_close()
+        self.assertTrue(data.startswith(b"HTTP/1.1 401"))
+
+    @gen_test
+    def test_early_return_with_data(self):
+        stream = self.connect(b"/early_return", connection_close=False)
+        stream.write(b"4\r\nasdf\r\n")
+        data = yield stream.read_until_close()
+        self.assertTrue(data.startswith(b"HTTP/1.1 401"))
+
+    @gen_test
+    def test_close_during_upload(self):
+        self.close_future = Future()  # type: Future[None]
+        stream = self.connect(b"/close_detection", connection_close=False)
+        stream.close()
+        yield self.close_future
+
+
+# Each method in this handler returns a yieldable object and yields to the
+# IOLoop so the future is not immediately ready.  Ensure that the
+# yieldables are respected and no method is called before the previous
+# one has completed.
+@stream_request_body
+class BaseFlowControlHandler(RequestHandler):
+    def initialize(self, test):
+        self.test = test
+        self.method = None
+        self.methods = []  # type: typing.List[str]
+
+    @contextlib.contextmanager
+    def in_method(self, method):
+        if self.method is not None:
+            self.test.fail("entered method %s while in %s" % (method, self.method))
+        self.method = method
+        self.methods.append(method)
+        try:
+            yield
+        finally:
+            self.method = None
+
+    @gen.coroutine
+    def prepare(self):
+        # Note that asynchronous prepare() does not block data_received,
+        # so we don't use in_method here.
+        self.methods.append("prepare")
+        yield gen.moment
+
+    @gen.coroutine
+    def post(self):
+        with self.in_method("post"):
+            yield gen.moment
+        self.write(dict(methods=self.methods))
+
+
+class BaseStreamingRequestFlowControlTest(object):
+    def get_httpserver_options(self):
+        # Use a small chunk size so flow control is relevant even though
+        # all the data arrives at once.
+        return dict(chunk_size=10, decompress_request=True)
+
+    def get_http_client(self):
+        # simple_httpclient only: curl doesn't support body_producer.
+        return SimpleAsyncHTTPClient()
+
+    # Test all the slightly different code paths for fixed, chunked, etc bodies.
+    def test_flow_control_fixed_body(self: typing.Any):
+        response = self.fetch("/", body="abcdefghijklmnopqrstuvwxyz", method="POST")
+        response.rethrow()
+        self.assertEqual(
+            json_decode(response.body),
+            dict(
+                methods=[
+                    "prepare",
+                    "data_received",
+                    "data_received",
+                    "data_received",
+                    "post",
+                ]
+            ),
+        )
+
+    def test_flow_control_chunked_body(self: typing.Any):
+        chunks = [b"abcd", b"efgh", b"ijkl"]
+
+        @gen.coroutine
+        def body_producer(write):
+            for i in chunks:
+                yield write(i)
+
+        response = self.fetch("/", body_producer=body_producer, method="POST")
+        response.rethrow()
+        self.assertEqual(
+            json_decode(response.body),
+            dict(
+                methods=[
+                    "prepare",
+                    "data_received",
+                    "data_received",
+                    "data_received",
+                    "post",
+                ]
+            ),
+        )
+
+    def test_flow_control_compressed_body(self: typing.Any):
+        bytesio = BytesIO()
+        gzip_file = gzip.GzipFile(mode="w", fileobj=bytesio)
+        gzip_file.write(b"abcdefghijklmnopqrstuvwxyz")
+        gzip_file.close()
+        compressed_body = bytesio.getvalue()
+        response = self.fetch(
+            "/",
+            body=compressed_body,
+            method="POST",
+            headers={"Content-Encoding": "gzip"},
+        )
+        response.rethrow()
+        self.assertEqual(
+            json_decode(response.body),
+            dict(
+                methods=[
+                    "prepare",
+                    "data_received",
+                    "data_received",
+                    "data_received",
+                    "post",
+                ]
+            ),
+        )
+
+
+class DecoratedStreamingRequestFlowControlTest(
+    BaseStreamingRequestFlowControlTest, WebTestCase
+):
+    def get_handlers(self):
+        class DecoratedFlowControlHandler(BaseFlowControlHandler):
+            @gen.coroutine
+            def data_received(self, data):
+                with self.in_method("data_received"):
+                    yield gen.moment
+
+        return [("/", DecoratedFlowControlHandler, dict(test=self))]
+
+
+class NativeStreamingRequestFlowControlTest(
+    BaseStreamingRequestFlowControlTest, WebTestCase
+):
+    def get_handlers(self):
+        class NativeFlowControlHandler(BaseFlowControlHandler):
+            async def data_received(self, data):
+                with self.in_method("data_received"):
+                    import asyncio
+
+                    await asyncio.sleep(0)
+
+        return [("/", NativeFlowControlHandler, dict(test=self))]
+
+
+class IncorrectContentLengthTest(SimpleHandlerTestCase):
+    def get_handlers(self):
+        test = self
+        self.server_error = None
+
+        # Manually set a content-length that doesn't match the actual content.
+        class TooHigh(RequestHandler):
+            def get(self):
+                self.set_header("Content-Length", "42")
+                try:
+                    self.finish("ok")
+                except Exception as e:
+                    test.server_error = e
+                    raise
+
+        class TooLow(RequestHandler):
+            def get(self):
+                self.set_header("Content-Length", "2")
+                try:
+                    self.finish("hello")
+                except Exception as e:
+                    test.server_error = e
+                    raise
+
+        return [("/high", TooHigh), ("/low", TooLow)]
+
+    def test_content_length_too_high(self):
+        # When the content-length is too high, the connection is simply
+        # closed without completing the response.  An error is logged on
+        # the server.
+        with ExpectLog(app_log, "(Uncaught exception|Exception in callback)"):
+            with ExpectLog(
+                gen_log,
+                "(Cannot send error response after headers written"
+                "|Failed to flush partial response)",
+            ):
+                with self.assertRaises(HTTPClientError):
+                    self.fetch("/high", raise_error=True)
+        self.assertEqual(
+            str(self.server_error), "Tried to write 40 bytes less than Content-Length"
+        )
+
+    def test_content_length_too_low(self):
+        # When the content-length is too low, the connection is closed
+        # without writing the last chunk, so the client never sees the request
+        # complete (which would be a framing error).
+        with ExpectLog(app_log, "(Uncaught exception|Exception in callback)"):
+            with ExpectLog(
+                gen_log,
+                "(Cannot send error response after headers written"
+                "|Failed to flush partial response)",
+            ):
+                with self.assertRaises(HTTPClientError):
+                    self.fetch("/low", raise_error=True)
+        self.assertEqual(
+            str(self.server_error), "Tried to write more data than Content-Length"
+        )
+
+
+class ClientCloseTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            if self.request.version.startswith("HTTP/1"):
+                # Simulate a connection closed by the client during
+                # request processing.  The client will see an error, but the
+                # server should respond gracefully (without logging errors
+                # because we were unable to write out as many bytes as
+                # Content-Length said we would)
+                self.request.connection.stream.close()  # type: ignore
+                self.write("hello")
+            else:
+                # TODO: add a HTTP2-compatible version of this test.
+                self.write("requires HTTP/1.x")
+
+    def test_client_close(self):
+        with self.assertRaises((HTTPClientError, unittest.SkipTest)):  # type: ignore
+            response = self.fetch("/", raise_error=True)
+            if response.body == b"requires HTTP/1.x":
+                self.skipTest("requires HTTP/1.x")
+            self.assertEqual(response.code, 599)
+
+
+class SignedValueTest(unittest.TestCase):
+    SECRET = "It's a secret to everybody"
+    SECRET_DICT = {0: "asdfbasdf", 1: "12312312", 2: "2342342"}
+
+    def past(self):
+        return self.present() - 86400 * 32
+
+    def present(self):
+        return 1300000000
+
+    def test_known_values(self):
+        signed_v1 = create_signed_value(
+            SignedValueTest.SECRET, "key", "value", version=1, clock=self.present
+        )
+        self.assertEqual(
+            signed_v1, b"dmFsdWU=|1300000000|31c934969f53e48164c50768b40cbd7e2daaaa4f"
+        )
+
+        signed_v2 = create_signed_value(
+            SignedValueTest.SECRET, "key", "value", version=2, clock=self.present
+        )
+        self.assertEqual(
+            signed_v2,
+            b"2|1:0|10:1300000000|3:key|8:dmFsdWU=|"
+            b"3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e152",
+        )
+
+        signed_default = create_signed_value(
+            SignedValueTest.SECRET, "key", "value", clock=self.present
+        )
+        self.assertEqual(signed_default, signed_v2)
+
+        decoded_v1 = decode_signed_value(
+            SignedValueTest.SECRET, "key", signed_v1, min_version=1, clock=self.present
+        )
+        self.assertEqual(decoded_v1, b"value")
+
+        decoded_v2 = decode_signed_value(
+            SignedValueTest.SECRET, "key", signed_v2, min_version=2, clock=self.present
+        )
+        self.assertEqual(decoded_v2, b"value")
+
+    def test_name_swap(self):
+        signed1 = create_signed_value(
+            SignedValueTest.SECRET, "key1", "value", clock=self.present
+        )
+        signed2 = create_signed_value(
+            SignedValueTest.SECRET, "key2", "value", clock=self.present
+        )
+        # Try decoding each string with the other's "name"
+        decoded1 = decode_signed_value(
+            SignedValueTest.SECRET, "key2", signed1, clock=self.present
+        )
+        self.assertIs(decoded1, None)
+        decoded2 = decode_signed_value(
+            SignedValueTest.SECRET, "key1", signed2, clock=self.present
+        )
+        self.assertIs(decoded2, None)
+
+    def test_expired(self):
+        signed = create_signed_value(
+            SignedValueTest.SECRET, "key1", "value", clock=self.past
+        )
+        decoded_past = decode_signed_value(
+            SignedValueTest.SECRET, "key1", signed, clock=self.past
+        )
+        self.assertEqual(decoded_past, b"value")
+        decoded_present = decode_signed_value(
+            SignedValueTest.SECRET, "key1", signed, clock=self.present
+        )
+        self.assertIs(decoded_present, None)
+
+    def test_payload_tampering(self):
+        # These cookies are variants of the one in test_known_values.
+        sig = "3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e152"
+
+        def validate(prefix):
+            return b"value" == decode_signed_value(
+                SignedValueTest.SECRET, "key", prefix + sig, clock=self.present
+            )
+
+        self.assertTrue(validate("2|1:0|10:1300000000|3:key|8:dmFsdWU=|"))
+        # Change key version
+        self.assertFalse(validate("2|1:1|10:1300000000|3:key|8:dmFsdWU=|"))
+        # length mismatch (field too short)
+        self.assertFalse(validate("2|1:0|10:130000000|3:key|8:dmFsdWU=|"))
+        # length mismatch (field too long)
+        self.assertFalse(validate("2|1:0|10:1300000000|3:keey|8:dmFsdWU=|"))
+
+    def test_signature_tampering(self):
+        prefix = "2|1:0|10:1300000000|3:key|8:dmFsdWU=|"
+
+        def validate(sig):
+            return b"value" == decode_signed_value(
+                SignedValueTest.SECRET, "key", prefix + sig, clock=self.present
+            )
+
+        self.assertTrue(
+            validate("3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e152")
+        )
+        # All zeros
+        self.assertFalse(validate("0" * 32))
+        # Change one character
+        self.assertFalse(
+            validate("4d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e152")
+        )
+        # Change another character
+        self.assertFalse(
+            validate("3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e153")
+        )
+        # Truncate
+        self.assertFalse(
+            validate("3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e15")
+        )
+        # Lengthen
+        self.assertFalse(
+            validate(
+                "3d4e60b996ff9c5d5788e333a0cba6f238a22c6c0f94788870e1a9ecd482e1538"
+            )
+        )
+
+    def test_non_ascii(self):
+        value = b"\xe9"
+        signed = create_signed_value(
+            SignedValueTest.SECRET, "key", value, clock=self.present
+        )
+        decoded = decode_signed_value(
+            SignedValueTest.SECRET, "key", signed, clock=self.present
+        )
+        self.assertEqual(value, decoded)
+
+    def test_key_versioning_read_write_default_key(self):
+        value = b"\xe9"
+        signed = create_signed_value(
+            SignedValueTest.SECRET_DICT, "key", value, clock=self.present, key_version=0
+        )
+        decoded = decode_signed_value(
+            SignedValueTest.SECRET_DICT, "key", signed, clock=self.present
+        )
+        self.assertEqual(value, decoded)
+
+    def test_key_versioning_read_write_non_default_key(self):
+        value = b"\xe9"
+        signed = create_signed_value(
+            SignedValueTest.SECRET_DICT, "key", value, clock=self.present, key_version=1
+        )
+        decoded = decode_signed_value(
+            SignedValueTest.SECRET_DICT, "key", signed, clock=self.present
+        )
+        self.assertEqual(value, decoded)
+
+    def test_key_versioning_invalid_key(self):
+        value = b"\xe9"
+        signed = create_signed_value(
+            SignedValueTest.SECRET_DICT, "key", value, clock=self.present, key_version=0
+        )
+        newkeys = SignedValueTest.SECRET_DICT.copy()
+        newkeys.pop(0)
+        decoded = decode_signed_value(newkeys, "key", signed, clock=self.present)
+        self.assertEqual(None, decoded)
+
+    def test_key_version_retrieval(self):
+        value = b"\xe9"
+        signed = create_signed_value(
+            SignedValueTest.SECRET_DICT, "key", value, clock=self.present, key_version=1
+        )
+        key_version = get_signature_key_version(signed)
+        self.assertEqual(1, key_version)
+
+
+class XSRFTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            version = int(self.get_argument("version", "2"))
+            # This would be a bad idea in a real app, but in this test
+            # it's fine.
+            self.settings["xsrf_cookie_version"] = version
+            self.write(self.xsrf_token)
+
+        def post(self):
+            self.write("ok")
+
+    def get_app_kwargs(self):
+        return dict(xsrf_cookies=True)
+
+    def setUp(self):
+        super().setUp()
+        self.xsrf_token = self.get_token()
+
+    def get_token(self, old_token=None, version=None):
+        if old_token is not None:
+            headers = self.cookie_headers(old_token)
+        else:
+            headers = None
+        response = self.fetch(
+            "/" if version is None else ("/?version=%d" % version), headers=headers
+        )
+        response.rethrow()
+        return native_str(response.body)
+
+    def cookie_headers(self, token=None):
+        if token is None:
+            token = self.xsrf_token
+        return {"Cookie": "_xsrf=" + token}
+
+    def test_xsrf_fail_no_token(self):
+        with ExpectLog(gen_log, ".*'_xsrf' argument missing"):
+            response = self.fetch("/", method="POST", body=b"")
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_fail_body_no_cookie(self):
+        with ExpectLog(gen_log, ".*XSRF cookie does not match POST"):
+            response = self.fetch(
+                "/",
+                method="POST",
+                body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            )
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_fail_argument_invalid_format(self):
+        with ExpectLog(gen_log, ".*'_xsrf' argument has invalid format"):
+            response = self.fetch(
+                "/",
+                method="POST",
+                headers=self.cookie_headers(),
+                body=urllib.parse.urlencode(dict(_xsrf="3|")),
+            )
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_fail_cookie_invalid_format(self):
+        with ExpectLog(gen_log, ".*XSRF cookie does not match POST"):
+            response = self.fetch(
+                "/",
+                method="POST",
+                headers=self.cookie_headers(token="3|"),
+                body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            )
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_fail_cookie_no_body(self):
+        with ExpectLog(gen_log, ".*'_xsrf' argument missing"):
+            response = self.fetch(
+                "/", method="POST", body=b"", headers=self.cookie_headers()
+            )
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_success_short_token(self):
+        response = self.fetch(
+            "/",
+            method="POST",
+            body=urllib.parse.urlencode(dict(_xsrf="deadbeef")),
+            headers=self.cookie_headers(token="deadbeef"),
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_xsrf_success_non_hex_token(self):
+        response = self.fetch(
+            "/",
+            method="POST",
+            body=urllib.parse.urlencode(dict(_xsrf="xoxo")),
+            headers=self.cookie_headers(token="xoxo"),
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_xsrf_success_post_body(self):
+        response = self.fetch(
+            "/",
+            method="POST",
+            body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            headers=self.cookie_headers(),
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_xsrf_success_query_string(self):
+        response = self.fetch(
+            "/?" + urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            method="POST",
+            body=b"",
+            headers=self.cookie_headers(),
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_xsrf_success_header(self):
+        response = self.fetch(
+            "/",
+            method="POST",
+            body=b"",
+            headers=dict(
+                {"X-Xsrftoken": self.xsrf_token},  # type: ignore
+                **self.cookie_headers()
+            ),
+        )
+        self.assertEqual(response.code, 200)
+
+    def test_distinct_tokens(self):
+        # Every request gets a distinct token.
+        NUM_TOKENS = 10
+        tokens = set()
+        for i in range(NUM_TOKENS):
+            tokens.add(self.get_token())
+        self.assertEqual(len(tokens), NUM_TOKENS)
+
+    def test_cross_user(self):
+        token2 = self.get_token()
+        # Each token can be used to authenticate its own request.
+        for token in (self.xsrf_token, token2):
+            response = self.fetch(
+                "/",
+                method="POST",
+                body=urllib.parse.urlencode(dict(_xsrf=token)),
+                headers=self.cookie_headers(token),
+            )
+            self.assertEqual(response.code, 200)
+        # Sending one in the cookie and the other in the body is not allowed.
+        for cookie_token, body_token in (
+            (self.xsrf_token, token2),
+            (token2, self.xsrf_token),
+        ):
+            with ExpectLog(gen_log, ".*XSRF cookie does not match POST"):
+                response = self.fetch(
+                    "/",
+                    method="POST",
+                    body=urllib.parse.urlencode(dict(_xsrf=body_token)),
+                    headers=self.cookie_headers(cookie_token),
+                )
+            self.assertEqual(response.code, 403)
+
+    def test_refresh_token(self):
+        token = self.xsrf_token
+        tokens_seen = set([token])
+        # A user's token is stable over time.  Refreshing the page in one tab
+        # might update the cookie while an older tab still has the old cookie
+        # in its DOM.  Simulate this scenario by passing a constant token
+        # in the body and re-querying for the token.
+        for i in range(5):
+            token = self.get_token(token)
+            # Tokens are encoded uniquely each time
+            tokens_seen.add(token)
+            response = self.fetch(
+                "/",
+                method="POST",
+                body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+                headers=self.cookie_headers(token),
+            )
+            self.assertEqual(response.code, 200)
+        self.assertEqual(len(tokens_seen), 6)
+
+    def test_versioning(self):
+        # Version 1 still produces distinct tokens per request.
+        self.assertNotEqual(self.get_token(version=1), self.get_token(version=1))
+
+        # Refreshed v1 tokens are all identical.
+        v1_token = self.get_token(version=1)
+        for i in range(5):
+            self.assertEqual(self.get_token(v1_token, version=1), v1_token)
+
+        # Upgrade to a v2 version of the same token
+        v2_token = self.get_token(v1_token)
+        self.assertNotEqual(v1_token, v2_token)
+        # Each v1 token can map to many v2 tokens.
+        self.assertNotEqual(v2_token, self.get_token(v1_token))
+
+        # The tokens are cross-compatible.
+        for cookie_token, body_token in ((v1_token, v2_token), (v2_token, v1_token)):
+            response = self.fetch(
+                "/",
+                method="POST",
+                body=urllib.parse.urlencode(dict(_xsrf=body_token)),
+                headers=self.cookie_headers(cookie_token),
+            )
+            self.assertEqual(response.code, 200)
+
+
+# A subset of the previous test with a different cookie name
+class XSRFCookieNameTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.write(self.xsrf_token)
+
+        def post(self):
+            self.write("ok")
+
+    def get_app_kwargs(self):
+        return dict(
+            xsrf_cookies=True,
+            xsrf_cookie_name="__Host-xsrf",
+            xsrf_cookie_kwargs={"secure": True},
+        )
+
+    def setUp(self):
+        super().setUp()
+        self.xsrf_token = self.get_token()
+
+    def get_token(self, old_token=None):
+        if old_token is not None:
+            headers = self.cookie_headers(old_token)
+        else:
+            headers = None
+        response = self.fetch("/", headers=headers)
+        response.rethrow()
+        return native_str(response.body)
+
+    def cookie_headers(self, token=None):
+        if token is None:
+            token = self.xsrf_token
+        return {"Cookie": "__Host-xsrf=" + token}
+
+    def test_xsrf_fail_no_token(self):
+        with ExpectLog(gen_log, ".*'_xsrf' argument missing"):
+            response = self.fetch("/", method="POST", body=b"")
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_fail_body_no_cookie(self):
+        with ExpectLog(gen_log, ".*XSRF cookie does not match POST"):
+            response = self.fetch(
+                "/",
+                method="POST",
+                body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            )
+        self.assertEqual(response.code, 403)
+
+    def test_xsrf_success_post_body(self):
+        response = self.fetch(
+            "/",
+            method="POST",
+            # Note that renaming the cookie doesn't rename the POST param
+            body=urllib.parse.urlencode(dict(_xsrf=self.xsrf_token)),
+            headers=self.cookie_headers(),
+        )
+        self.assertEqual(response.code, 200)
+
+
+class XSRFCookieKwargsTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.write(self.xsrf_token)
+
+    def get_app_kwargs(self):
+        return dict(
+            xsrf_cookies=True, xsrf_cookie_kwargs=dict(httponly=True, expires_days=2)
+        )
+
+    def test_xsrf_httponly(self):
+        response = self.fetch("/")
+        self.assertIn("httponly;", response.headers["Set-Cookie"].lower())
+        self.assertIn("expires=", response.headers["Set-Cookie"].lower())
+        header = response.headers.get("Set-Cookie")
+        assert header is not None
+        match = re.match(".*; expires=(?P<expires>.+);.*", header)
+        assert match is not None
+
+        expires = datetime.datetime.utcnow() + datetime.timedelta(days=2)
+        parsed = email.utils.parsedate(match.groupdict()["expires"])
+        assert parsed is not None
+        header_expires = datetime.datetime(*parsed[:6])
+        self.assertTrue(abs((expires - header_expires).total_seconds()) < 10)
+
+
+class FinishExceptionTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            self.set_status(401)
+            self.set_header("WWW-Authenticate", 'Basic realm="something"')
+            if self.get_argument("finish_value", ""):
+                raise Finish("authentication required")
+            else:
+                self.write("authentication required")
+                raise Finish()
+
+    def test_finish_exception(self):
+        for u in ["/", "/?finish_value=1"]:
+            response = self.fetch(u)
+            self.assertEqual(response.code, 401)
+            self.assertEqual(
+                'Basic realm="something"', response.headers.get("WWW-Authenticate")
+            )
+            self.assertEqual(b"authentication required", response.body)
+
+
+class DecoratorTest(WebTestCase):
+    def get_handlers(self):
+        class RemoveSlashHandler(RequestHandler):
+            @removeslash
+            def get(self):
+                pass
+
+        class AddSlashHandler(RequestHandler):
+            @addslash
+            def get(self):
+                pass
+
+        return [("/removeslash/", RemoveSlashHandler), ("/addslash", AddSlashHandler)]
+
+    def test_removeslash(self):
+        response = self.fetch("/removeslash/", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/removeslash")
+
+        response = self.fetch("/removeslash/?foo=bar", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/removeslash?foo=bar")
+
+    def test_addslash(self):
+        response = self.fetch("/addslash", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/addslash/")
+
+        response = self.fetch("/addslash?foo=bar", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/addslash/?foo=bar")
+
+
+class CacheTest(WebTestCase):
+    def get_handlers(self):
+        class EtagHandler(RequestHandler):
+            def get(self, computed_etag):
+                self.write(computed_etag)
+
+            def compute_etag(self):
+                return self._write_buffer[0]
+
+        return [("/etag/(.*)", EtagHandler)]
+
+    def test_wildcard_etag(self):
+        computed_etag = '"xyzzy"'
+        etags = "*"
+        self._test_etag(computed_etag, etags, 304)
+
+    def test_strong_etag_match(self):
+        computed_etag = '"xyzzy"'
+        etags = '"xyzzy"'
+        self._test_etag(computed_etag, etags, 304)
+
+    def test_multiple_strong_etag_match(self):
+        computed_etag = '"xyzzy1"'
+        etags = '"xyzzy1", "xyzzy2"'
+        self._test_etag(computed_etag, etags, 304)
+
+    def test_strong_etag_not_match(self):
+        computed_etag = '"xyzzy"'
+        etags = '"xyzzy1"'
+        self._test_etag(computed_etag, etags, 200)
+
+    def test_multiple_strong_etag_not_match(self):
+        computed_etag = '"xyzzy"'
+        etags = '"xyzzy1", "xyzzy2"'
+        self._test_etag(computed_etag, etags, 200)
+
+    def test_weak_etag_match(self):
+        computed_etag = '"xyzzy1"'
+        etags = 'W/"xyzzy1"'
+        self._test_etag(computed_etag, etags, 304)
+
+    def test_multiple_weak_etag_match(self):
+        computed_etag = '"xyzzy2"'
+        etags = 'W/"xyzzy1", W/"xyzzy2"'
+        self._test_etag(computed_etag, etags, 304)
+
+    def test_weak_etag_not_match(self):
+        computed_etag = '"xyzzy2"'
+        etags = 'W/"xyzzy1"'
+        self._test_etag(computed_etag, etags, 200)
+
+    def test_multiple_weak_etag_not_match(self):
+        computed_etag = '"xyzzy3"'
+        etags = 'W/"xyzzy1", W/"xyzzy2"'
+        self._test_etag(computed_etag, etags, 200)
+
+    def _test_etag(self, computed_etag, etags, status_code):
+        response = self.fetch(
+            "/etag/" + computed_etag, headers={"If-None-Match": etags}
+        )
+        self.assertEqual(response.code, status_code)
+
+
+class RequestSummaryTest(SimpleHandlerTestCase):
+    class Handler(RequestHandler):
+        def get(self):
+            # remote_ip is optional, although it's set by
+            # both HTTPServer and WSGIAdapter.
+            # Clobber it to make sure it doesn't break logging.
+            self.request.remote_ip = None
+            self.finish(self._request_summary())
+
+    def test_missing_remote_ip(self):
+        resp = self.fetch("/")
+        self.assertEqual(resp.body, b"GET / (None)")
+
+
+class HTTPErrorTest(unittest.TestCase):
+    def test_copy(self):
+        e = HTTPError(403, reason="Go away")
+        e2 = copy.copy(e)
+        self.assertIsNot(e, e2)
+        self.assertEqual(e.status_code, e2.status_code)
+        self.assertEqual(e.reason, e2.reason)
+
+
+class ApplicationTest(AsyncTestCase):
+    def test_listen(self):
+        app = Application([])
+        server = app.listen(0, address="127.0.0.1")
+        server.stop()
+
+
+class URLSpecReverseTest(unittest.TestCase):
+    def test_reverse(self):
+        self.assertEqual("/favicon.ico", url(r"/favicon\.ico", None).reverse())
+        self.assertEqual("/favicon.ico", url(r"^/favicon\.ico$", None).reverse())
+
+    def test_non_reversible(self):
+        # URLSpecs are non-reversible if they include non-constant
+        # regex features outside capturing groups. Currently, this is
+        # only strictly enforced for backslash-escaped character
+        # classes.
+        paths = [r"^/api/v\d+/foo/(\w+)$"]
+        for path in paths:
+            # A URLSpec can still be created even if it cannot be reversed.
+            url_spec = url(path, None)
+            try:
+                result = url_spec.reverse()
+                self.fail(
+                    "did not get expected exception when reversing %s. "
+                    "result: %s" % (path, result)
+                )
+            except ValueError:
+                pass
+
+    def test_reverse_arguments(self):
+        self.assertEqual(
+            "/api/v1/foo/bar", url(r"^/api/v1/foo/(\w+)$", None).reverse("bar")
+        )
+        self.assertEqual(
+            "/api.v1/foo/5/icon.png",
+            url(r"/api\.v1/foo/([0-9]+)/icon\.png", None).reverse(5),
+        )
+
+
+class RedirectHandlerTest(WebTestCase):
+    def get_handlers(self):
+        return [
+            ("/src", WebRedirectHandler, {"url": "/dst"}),
+            ("/src2", WebRedirectHandler, {"url": "/dst2?foo=bar"}),
+            (r"/(.*?)/(.*?)/(.*)", WebRedirectHandler, {"url": "/{1}/{0}/{2}"}),
+        ]
+
+    def test_basic_redirect(self):
+        response = self.fetch("/src", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/dst")
+
+    def test_redirect_with_argument(self):
+        response = self.fetch("/src?foo=bar", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/dst?foo=bar")
+
+    def test_redirect_with_appending_argument(self):
+        response = self.fetch("/src2?foo2=bar2", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/dst2?foo=bar&foo2=bar2")
+
+    def test_redirect_pattern(self):
+        response = self.fetch("/a/b/c", follow_redirects=False)
+        self.assertEqual(response.code, 301)
+        self.assertEqual(response.headers["Location"], "/b/a/c")
+
+
+class AcceptLanguageTest(WebTestCase):
+    """Test evaluation of Accept-Language header"""
+
+    def get_handlers(self):
+        locale.load_gettext_translations(
+            os.path.join(os.path.dirname(__file__), "gettext_translations"),
+            "tornado_test",
+        )
+
+        class AcceptLanguageHandler(RequestHandler):
+            def get(self):
+                self.set_header(
+                    "Content-Language", self.get_browser_locale().code.replace("_", "-")
+                )
+                self.finish(b"")
+
+        return [
+            ("/", AcceptLanguageHandler),
+        ]
+
+    def test_accept_language(self):
+        response = self.fetch("/", headers={"Accept-Language": "fr-FR;q=0.9"})
+        self.assertEqual(response.headers["Content-Language"], "fr-FR")
+
+        response = self.fetch("/", headers={"Accept-Language": "fr-FR; q=0.9"})
+        self.assertEqual(response.headers["Content-Language"], "fr-FR")
+
+    def test_accept_language_ignore(self):
+        response = self.fetch("/", headers={"Accept-Language": "fr-FR;q=0"})
+        self.assertEqual(response.headers["Content-Language"], "en-US")
+
+    def test_accept_language_invalid(self):
+        response = self.fetch("/", headers={"Accept-Language": "fr-FR;q=-1"})
+        self.assertEqual(response.headers["Content-Language"], "en-US")
diff --git a/venv/lib/python3.9/site-packages/tornado/test/websocket_test.py b/venv/lib/python3.9/site-packages/tornado/test/websocket_test.py
new file mode 100644
index 00000000..f90c5f2c
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/websocket_test.py
@@ -0,0 +1,858 @@
+import asyncio
+import functools
+import socket
+import traceback
+import typing
+import unittest
+
+from tornado.concurrent import Future
+from tornado import gen
+from tornado.httpclient import HTTPError, HTTPRequest
+from tornado.locks import Event
+from tornado.log import gen_log, app_log
+from tornado.netutil import Resolver
+from tornado.simple_httpclient import SimpleAsyncHTTPClient
+from tornado.template import DictLoader
+from tornado.testing import AsyncHTTPTestCase, gen_test, bind_unused_port, ExpectLog
+from tornado.web import Application, RequestHandler
+
+try:
+    import tornado.websocket  # noqa: F401
+    from tornado.util import _websocket_mask_python
+except ImportError:
+    # The unittest module presents misleading errors on ImportError
+    # (it acts as if websocket_test could not be found, hiding the underlying
+    # error).  If we get an ImportError here (which could happen due to
+    # TORNADO_EXTENSION=1), print some extra information before failing.
+    traceback.print_exc()
+    raise
+
+from tornado.websocket import (
+    WebSocketHandler,
+    websocket_connect,
+    WebSocketError,
+    WebSocketClosedError,
+)
+
+try:
+    from tornado import speedups
+except ImportError:
+    speedups = None  # type: ignore
+
+
+class TestWebSocketHandler(WebSocketHandler):
+    """Base class for testing handlers that exposes the on_close event.
+
+    This allows for tests to see the close code and reason on the
+    server side.
+
+    """
+
+    def initialize(self, close_future=None, compression_options=None):
+        self.close_future = close_future
+        self.compression_options = compression_options
+
+    def get_compression_options(self):
+        return self.compression_options
+
+    def on_close(self):
+        if self.close_future is not None:
+            self.close_future.set_result((self.close_code, self.close_reason))
+
+
+class EchoHandler(TestWebSocketHandler):
+    @gen.coroutine
+    def on_message(self, message):
+        try:
+            yield self.write_message(message, isinstance(message, bytes))
+        except asyncio.CancelledError:
+            pass
+        except WebSocketClosedError:
+            pass
+
+
+class ErrorInOnMessageHandler(TestWebSocketHandler):
+    def on_message(self, message):
+        1 / 0
+
+
+class HeaderHandler(TestWebSocketHandler):
+    def open(self):
+        methods_to_test = [
+            functools.partial(self.write, "This should not work"),
+            functools.partial(self.redirect, "http://localhost/elsewhere"),
+            functools.partial(self.set_header, "X-Test", ""),
+            functools.partial(self.set_cookie, "Chocolate", "Chip"),
+            functools.partial(self.set_status, 503),
+            self.flush,
+            self.finish,
+        ]
+        for method in methods_to_test:
+            try:
+                # In a websocket context, many RequestHandler methods
+                # raise RuntimeErrors.
+                method()  # type: ignore
+                raise Exception("did not get expected exception")
+            except RuntimeError:
+                pass
+        self.write_message(self.request.headers.get("X-Test", ""))
+
+
+class HeaderEchoHandler(TestWebSocketHandler):
+    def set_default_headers(self):
+        self.set_header("X-Extra-Response-Header", "Extra-Response-Value")
+
+    def prepare(self):
+        for k, v in self.request.headers.get_all():
+            if k.lower().startswith("x-test"):
+                self.set_header(k, v)
+
+
+class NonWebSocketHandler(RequestHandler):
+    def get(self):
+        self.write("ok")
+
+
+class RedirectHandler(RequestHandler):
+    def get(self):
+        self.redirect("/echo")
+
+
+class CloseReasonHandler(TestWebSocketHandler):
+    def open(self):
+        self.on_close_called = False
+        self.close(1001, "goodbye")
+
+
+class AsyncPrepareHandler(TestWebSocketHandler):
+    @gen.coroutine
+    def prepare(self):
+        yield gen.moment
+
+    def on_message(self, message):
+        self.write_message(message)
+
+
+class PathArgsHandler(TestWebSocketHandler):
+    def open(self, arg):
+        self.write_message(arg)
+
+
+class CoroutineOnMessageHandler(TestWebSocketHandler):
+    def initialize(self, **kwargs):
+        super().initialize(**kwargs)
+        self.sleeping = 0
+
+    @gen.coroutine
+    def on_message(self, message):
+        if self.sleeping > 0:
+            self.write_message("another coroutine is already sleeping")
+        self.sleeping += 1
+        yield gen.sleep(0.01)
+        self.sleeping -= 1
+        self.write_message(message)
+
+
+class RenderMessageHandler(TestWebSocketHandler):
+    def on_message(self, message):
+        self.write_message(self.render_string("message.html", message=message))
+
+
+class SubprotocolHandler(TestWebSocketHandler):
+    def initialize(self, **kwargs):
+        super().initialize(**kwargs)
+        self.select_subprotocol_called = False
+
+    def select_subprotocol(self, subprotocols):
+        if self.select_subprotocol_called:
+            raise Exception("select_subprotocol called twice")
+        self.select_subprotocol_called = True
+        if "goodproto" in subprotocols:
+            return "goodproto"
+        return None
+
+    def open(self):
+        if not self.select_subprotocol_called:
+            raise Exception("select_subprotocol not called")
+        self.write_message("subprotocol=%s" % self.selected_subprotocol)
+
+
+class OpenCoroutineHandler(TestWebSocketHandler):
+    def initialize(self, test, **kwargs):
+        super().initialize(**kwargs)
+        self.test = test
+        self.open_finished = False
+
+    @gen.coroutine
+    def open(self):
+        yield self.test.message_sent.wait()
+        yield gen.sleep(0.010)
+        self.open_finished = True
+
+    def on_message(self, message):
+        if not self.open_finished:
+            raise Exception("on_message called before open finished")
+        self.write_message("ok")
+
+
+class ErrorInOpenHandler(TestWebSocketHandler):
+    def open(self):
+        raise Exception("boom")
+
+
+class ErrorInAsyncOpenHandler(TestWebSocketHandler):
+    async def open(self):
+        await asyncio.sleep(0)
+        raise Exception("boom")
+
+
+class NoDelayHandler(TestWebSocketHandler):
+    def open(self):
+        self.set_nodelay(True)
+        self.write_message("hello")
+
+
+class WebSocketBaseTestCase(AsyncHTTPTestCase):
+    @gen.coroutine
+    def ws_connect(self, path, **kwargs):
+        ws = yield websocket_connect(
+            "ws://127.0.0.1:%d%s" % (self.get_http_port(), path), **kwargs
+        )
+        raise gen.Return(ws)
+
+
+class WebSocketTest(WebSocketBaseTestCase):
+    def get_app(self):
+        self.close_future = Future()  # type: Future[None]
+        return Application(
+            [
+                ("/echo", EchoHandler, dict(close_future=self.close_future)),
+                ("/non_ws", NonWebSocketHandler),
+                ("/redirect", RedirectHandler),
+                ("/header", HeaderHandler, dict(close_future=self.close_future)),
+                (
+                    "/header_echo",
+                    HeaderEchoHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/close_reason",
+                    CloseReasonHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/error_in_on_message",
+                    ErrorInOnMessageHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/async_prepare",
+                    AsyncPrepareHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/path_args/(.*)",
+                    PathArgsHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/coroutine",
+                    CoroutineOnMessageHandler,
+                    dict(close_future=self.close_future),
+                ),
+                ("/render", RenderMessageHandler, dict(close_future=self.close_future)),
+                (
+                    "/subprotocol",
+                    SubprotocolHandler,
+                    dict(close_future=self.close_future),
+                ),
+                (
+                    "/open_coroutine",
+                    OpenCoroutineHandler,
+                    dict(close_future=self.close_future, test=self),
+                ),
+                ("/error_in_open", ErrorInOpenHandler),
+                ("/error_in_async_open", ErrorInAsyncOpenHandler),
+                ("/nodelay", NoDelayHandler),
+            ],
+            template_loader=DictLoader({"message.html": "<b>{{ message }}</b>"}),
+        )
+
+    def get_http_client(self):
+        # These tests require HTTP/1; force the use of SimpleAsyncHTTPClient.
+        return SimpleAsyncHTTPClient()
+
+    def tearDown(self):
+        super().tearDown()
+        RequestHandler._template_loaders.clear()
+
+    def test_http_request(self):
+        # WS server, HTTP client.
+        response = self.fetch("/echo")
+        self.assertEqual(response.code, 400)
+
+    def test_missing_websocket_key(self):
+        response = self.fetch(
+            "/echo",
+            headers={
+                "Connection": "Upgrade",
+                "Upgrade": "WebSocket",
+                "Sec-WebSocket-Version": "13",
+            },
+        )
+        self.assertEqual(response.code, 400)
+
+    def test_bad_websocket_version(self):
+        response = self.fetch(
+            "/echo",
+            headers={
+                "Connection": "Upgrade",
+                "Upgrade": "WebSocket",
+                "Sec-WebSocket-Version": "12",
+            },
+        )
+        self.assertEqual(response.code, 426)
+
+    @gen_test
+    def test_websocket_gen(self):
+        ws = yield self.ws_connect("/echo")
+        yield ws.write_message("hello")
+        response = yield ws.read_message()
+        self.assertEqual(response, "hello")
+
+    def test_websocket_callbacks(self):
+        websocket_connect(
+            "ws://127.0.0.1:%d/echo" % self.get_http_port(), callback=self.stop
+        )
+        ws = self.wait().result()
+        ws.write_message("hello")
+        ws.read_message(self.stop)
+        response = self.wait().result()
+        self.assertEqual(response, "hello")
+        self.close_future.add_done_callback(lambda f: self.stop())
+        ws.close()
+        self.wait()
+
+    @gen_test
+    def test_binary_message(self):
+        ws = yield self.ws_connect("/echo")
+        ws.write_message(b"hello \xe9", binary=True)
+        response = yield ws.read_message()
+        self.assertEqual(response, b"hello \xe9")
+
+    @gen_test
+    def test_unicode_message(self):
+        ws = yield self.ws_connect("/echo")
+        ws.write_message("hello \u00e9")
+        response = yield ws.read_message()
+        self.assertEqual(response, "hello \u00e9")
+
+    @gen_test
+    def test_error_in_closed_client_write_message(self):
+        ws = yield self.ws_connect("/echo")
+        ws.close()
+        with self.assertRaises(WebSocketClosedError):
+            ws.write_message("hello \u00e9")
+
+    @gen_test
+    def test_render_message(self):
+        ws = yield self.ws_connect("/render")
+        ws.write_message("hello")
+        response = yield ws.read_message()
+        self.assertEqual(response, "<b>hello</b>")
+
+    @gen_test
+    def test_error_in_on_message(self):
+        ws = yield self.ws_connect("/error_in_on_message")
+        ws.write_message("hello")
+        with ExpectLog(app_log, "Uncaught exception"):
+            response = yield ws.read_message()
+        self.assertIs(response, None)
+
+    @gen_test
+    def test_websocket_http_fail(self):
+        with self.assertRaises(HTTPError) as cm:
+            yield self.ws_connect("/notfound")
+        self.assertEqual(cm.exception.code, 404)
+
+    @gen_test
+    def test_websocket_http_success(self):
+        with self.assertRaises(WebSocketError):
+            yield self.ws_connect("/non_ws")
+
+    @gen_test
+    def test_websocket_http_redirect(self):
+        with self.assertRaises(HTTPError):
+            yield self.ws_connect("/redirect")
+
+    @gen_test
+    def test_websocket_network_fail(self):
+        sock, port = bind_unused_port()
+        sock.close()
+        with self.assertRaises(IOError):
+            with ExpectLog(gen_log, ".*", required=False):
+                yield websocket_connect(
+                    "ws://127.0.0.1:%d/" % port, connect_timeout=3600
+                )
+
+    @gen_test
+    def test_websocket_close_buffered_data(self):
+        ws = yield websocket_connect("ws://127.0.0.1:%d/echo" % self.get_http_port())
+        ws.write_message("hello")
+        ws.write_message("world")
+        # Close the underlying stream.
+        ws.stream.close()
+
+    @gen_test
+    def test_websocket_headers(self):
+        # Ensure that arbitrary headers can be passed through websocket_connect.
+        ws = yield websocket_connect(
+            HTTPRequest(
+                "ws://127.0.0.1:%d/header" % self.get_http_port(),
+                headers={"X-Test": "hello"},
+            )
+        )
+        response = yield ws.read_message()
+        self.assertEqual(response, "hello")
+
+    @gen_test
+    def test_websocket_header_echo(self):
+        # Ensure that headers can be returned in the response.
+        # Specifically, that arbitrary headers passed through websocket_connect
+        # can be returned.
+        ws = yield websocket_connect(
+            HTTPRequest(
+                "ws://127.0.0.1:%d/header_echo" % self.get_http_port(),
+                headers={"X-Test-Hello": "hello"},
+            )
+        )
+        self.assertEqual(ws.headers.get("X-Test-Hello"), "hello")
+        self.assertEqual(
+            ws.headers.get("X-Extra-Response-Header"), "Extra-Response-Value"
+        )
+
+    @gen_test
+    def test_server_close_reason(self):
+        ws = yield self.ws_connect("/close_reason")
+        msg = yield ws.read_message()
+        # A message of None means the other side closed the connection.
+        self.assertIs(msg, None)
+        self.assertEqual(ws.close_code, 1001)
+        self.assertEqual(ws.close_reason, "goodbye")
+        # The on_close callback is called no matter which side closed.
+        code, reason = yield self.close_future
+        # The client echoed the close code it received to the server,
+        # so the server's close code (returned via close_future) is
+        # the same.
+        self.assertEqual(code, 1001)
+
+    @gen_test
+    def test_client_close_reason(self):
+        ws = yield self.ws_connect("/echo")
+        ws.close(1001, "goodbye")
+        code, reason = yield self.close_future
+        self.assertEqual(code, 1001)
+        self.assertEqual(reason, "goodbye")
+
+    @gen_test
+    def test_write_after_close(self):
+        ws = yield self.ws_connect("/close_reason")
+        msg = yield ws.read_message()
+        self.assertIs(msg, None)
+        with self.assertRaises(WebSocketClosedError):
+            ws.write_message("hello")
+
+    @gen_test
+    def test_async_prepare(self):
+        # Previously, an async prepare method triggered a bug that would
+        # result in a timeout on test shutdown (and a memory leak).
+        ws = yield self.ws_connect("/async_prepare")
+        ws.write_message("hello")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello")
+
+    @gen_test
+    def test_path_args(self):
+        ws = yield self.ws_connect("/path_args/hello")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello")
+
+    @gen_test
+    def test_coroutine(self):
+        ws = yield self.ws_connect("/coroutine")
+        # Send both messages immediately, coroutine must process one at a time.
+        yield ws.write_message("hello1")
+        yield ws.write_message("hello2")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello1")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello2")
+
+    @gen_test
+    def test_check_origin_valid_no_path(self):
+        port = self.get_http_port()
+
+        url = "ws://127.0.0.1:%d/echo" % port
+        headers = {"Origin": "http://127.0.0.1:%d" % port}
+
+        ws = yield websocket_connect(HTTPRequest(url, headers=headers))
+        ws.write_message("hello")
+        response = yield ws.read_message()
+        self.assertEqual(response, "hello")
+
+    @gen_test
+    def test_check_origin_valid_with_path(self):
+        port = self.get_http_port()
+
+        url = "ws://127.0.0.1:%d/echo" % port
+        headers = {"Origin": "http://127.0.0.1:%d/something" % port}
+
+        ws = yield websocket_connect(HTTPRequest(url, headers=headers))
+        ws.write_message("hello")
+        response = yield ws.read_message()
+        self.assertEqual(response, "hello")
+
+    @gen_test
+    def test_check_origin_invalid_partial_url(self):
+        port = self.get_http_port()
+
+        url = "ws://127.0.0.1:%d/echo" % port
+        headers = {"Origin": "127.0.0.1:%d" % port}
+
+        with self.assertRaises(HTTPError) as cm:
+            yield websocket_connect(HTTPRequest(url, headers=headers))
+        self.assertEqual(cm.exception.code, 403)
+
+    @gen_test
+    def test_check_origin_invalid(self):
+        port = self.get_http_port()
+
+        url = "ws://127.0.0.1:%d/echo" % port
+        # Host is 127.0.0.1, which should not be accessible from some other
+        # domain
+        headers = {"Origin": "http://somewhereelse.com"}
+
+        with self.assertRaises(HTTPError) as cm:
+            yield websocket_connect(HTTPRequest(url, headers=headers))
+
+        self.assertEqual(cm.exception.code, 403)
+
+    @gen_test
+    def test_check_origin_invalid_subdomains(self):
+        port = self.get_http_port()
+
+        # CaresResolver may return ipv6-only results for localhost, but our
+        # server is only running on ipv4. Test for this edge case and skip
+        # the test if it happens.
+        addrinfo = yield Resolver().resolve("localhost", port)
+        families = set(addr[0] for addr in addrinfo)
+        if socket.AF_INET not in families:
+            self.skipTest("localhost does not resolve to ipv4")
+            return
+
+        url = "ws://localhost:%d/echo" % port
+        # Subdomains should be disallowed by default.  If we could pass a
+        # resolver to websocket_connect we could test sibling domains as well.
+        headers = {"Origin": "http://subtenant.localhost"}
+
+        with self.assertRaises(HTTPError) as cm:
+            yield websocket_connect(HTTPRequest(url, headers=headers))
+
+        self.assertEqual(cm.exception.code, 403)
+
+    @gen_test
+    def test_subprotocols(self):
+        ws = yield self.ws_connect(
+            "/subprotocol", subprotocols=["badproto", "goodproto"]
+        )
+        self.assertEqual(ws.selected_subprotocol, "goodproto")
+        res = yield ws.read_message()
+        self.assertEqual(res, "subprotocol=goodproto")
+
+    @gen_test
+    def test_subprotocols_not_offered(self):
+        ws = yield self.ws_connect("/subprotocol")
+        self.assertIs(ws.selected_subprotocol, None)
+        res = yield ws.read_message()
+        self.assertEqual(res, "subprotocol=None")
+
+    @gen_test
+    def test_open_coroutine(self):
+        self.message_sent = Event()
+        ws = yield self.ws_connect("/open_coroutine")
+        yield ws.write_message("hello")
+        self.message_sent.set()
+        res = yield ws.read_message()
+        self.assertEqual(res, "ok")
+
+    @gen_test
+    def test_error_in_open(self):
+        with ExpectLog(app_log, "Uncaught exception"):
+            ws = yield self.ws_connect("/error_in_open")
+            res = yield ws.read_message()
+        self.assertIsNone(res)
+
+    @gen_test
+    def test_error_in_async_open(self):
+        with ExpectLog(app_log, "Uncaught exception"):
+            ws = yield self.ws_connect("/error_in_async_open")
+            res = yield ws.read_message()
+        self.assertIsNone(res)
+
+    @gen_test
+    def test_nodelay(self):
+        ws = yield self.ws_connect("/nodelay")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello")
+
+
+class NativeCoroutineOnMessageHandler(TestWebSocketHandler):
+    def initialize(self, **kwargs):
+        super().initialize(**kwargs)
+        self.sleeping = 0
+
+    async def on_message(self, message):
+        if self.sleeping > 0:
+            self.write_message("another coroutine is already sleeping")
+        self.sleeping += 1
+        await gen.sleep(0.01)
+        self.sleeping -= 1
+        self.write_message(message)
+
+
+class WebSocketNativeCoroutineTest(WebSocketBaseTestCase):
+    def get_app(self):
+        return Application([("/native", NativeCoroutineOnMessageHandler)])
+
+    @gen_test
+    def test_native_coroutine(self):
+        ws = yield self.ws_connect("/native")
+        # Send both messages immediately, coroutine must process one at a time.
+        yield ws.write_message("hello1")
+        yield ws.write_message("hello2")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello1")
+        res = yield ws.read_message()
+        self.assertEqual(res, "hello2")
+
+
+class CompressionTestMixin(object):
+    MESSAGE = "Hello world. Testing 123 123"
+
+    def get_app(self):
+        class LimitedHandler(TestWebSocketHandler):
+            @property
+            def max_message_size(self):
+                return 1024
+
+            def on_message(self, message):
+                self.write_message(str(len(message)))
+
+        return Application(
+            [
+                (
+                    "/echo",
+                    EchoHandler,
+                    dict(compression_options=self.get_server_compression_options()),
+                ),
+                (
+                    "/limited",
+                    LimitedHandler,
+                    dict(compression_options=self.get_server_compression_options()),
+                ),
+            ]
+        )
+
+    def get_server_compression_options(self):
+        return None
+
+    def get_client_compression_options(self):
+        return None
+
+    def verify_wire_bytes(self, bytes_in: int, bytes_out: int) -> None:
+        raise NotImplementedError()
+
+    @gen_test
+    def test_message_sizes(self: typing.Any):
+        ws = yield self.ws_connect(
+            "/echo", compression_options=self.get_client_compression_options()
+        )
+        # Send the same message three times so we can measure the
+        # effect of the context_takeover options.
+        for i in range(3):
+            ws.write_message(self.MESSAGE)
+            response = yield ws.read_message()
+            self.assertEqual(response, self.MESSAGE)
+        self.assertEqual(ws.protocol._message_bytes_out, len(self.MESSAGE) * 3)
+        self.assertEqual(ws.protocol._message_bytes_in, len(self.MESSAGE) * 3)
+        self.verify_wire_bytes(ws.protocol._wire_bytes_in, ws.protocol._wire_bytes_out)
+
+    @gen_test
+    def test_size_limit(self: typing.Any):
+        ws = yield self.ws_connect(
+            "/limited", compression_options=self.get_client_compression_options()
+        )
+        # Small messages pass through.
+        ws.write_message("a" * 128)
+        response = yield ws.read_message()
+        self.assertEqual(response, "128")
+        # This message is too big after decompression, but it compresses
+        # down to a size that will pass the initial checks.
+        ws.write_message("a" * 2048)
+        response = yield ws.read_message()
+        self.assertIsNone(response)
+
+
+class UncompressedTestMixin(CompressionTestMixin):
+    """Specialization of CompressionTestMixin when we expect no compression."""
+
+    def verify_wire_bytes(self: typing.Any, bytes_in, bytes_out):
+        # Bytes out includes the 4-byte mask key per message.
+        self.assertEqual(bytes_out, 3 * (len(self.MESSAGE) + 6))
+        self.assertEqual(bytes_in, 3 * (len(self.MESSAGE) + 2))
+
+
+class NoCompressionTest(UncompressedTestMixin, WebSocketBaseTestCase):
+    pass
+
+
+# If only one side tries to compress, the extension is not negotiated.
+class ServerOnlyCompressionTest(UncompressedTestMixin, WebSocketBaseTestCase):
+    def get_server_compression_options(self):
+        return {}
+
+
+class ClientOnlyCompressionTest(UncompressedTestMixin, WebSocketBaseTestCase):
+    def get_client_compression_options(self):
+        return {}
+
+
+class DefaultCompressionTest(CompressionTestMixin, WebSocketBaseTestCase):
+    def get_server_compression_options(self):
+        return {}
+
+    def get_client_compression_options(self):
+        return {}
+
+    def verify_wire_bytes(self, bytes_in, bytes_out):
+        self.assertLess(bytes_out, 3 * (len(self.MESSAGE) + 6))
+        self.assertLess(bytes_in, 3 * (len(self.MESSAGE) + 2))
+        # Bytes out includes the 4 bytes mask key per message.
+        self.assertEqual(bytes_out, bytes_in + 12)
+
+
+class MaskFunctionMixin(object):
+    # Subclasses should define self.mask(mask, data)
+    def mask(self, mask: bytes, data: bytes) -> bytes:
+        raise NotImplementedError()
+
+    def test_mask(self: typing.Any):
+        self.assertEqual(self.mask(b"abcd", b""), b"")
+        self.assertEqual(self.mask(b"abcd", b"b"), b"\x03")
+        self.assertEqual(self.mask(b"abcd", b"54321"), b"TVPVP")
+        self.assertEqual(self.mask(b"ZXCV", b"98765432"), b"c`t`olpd")
+        # Include test cases with \x00 bytes (to ensure that the C
+        # extension isn't depending on null-terminated strings) and
+        # bytes with the high bit set (to smoke out signedness issues).
+        self.assertEqual(
+            self.mask(b"\x00\x01\x02\x03", b"\xff\xfb\xfd\xfc\xfe\xfa"),
+            b"\xff\xfa\xff\xff\xfe\xfb",
+        )
+        self.assertEqual(
+            self.mask(b"\xff\xfb\xfd\xfc", b"\x00\x01\x02\x03\x04\x05"),
+            b"\xff\xfa\xff\xff\xfb\xfe",
+        )
+
+
+class PythonMaskFunctionTest(MaskFunctionMixin, unittest.TestCase):
+    def mask(self, mask, data):
+        return _websocket_mask_python(mask, data)
+
+
+@unittest.skipIf(speedups is None, "tornado.speedups module not present")
+class CythonMaskFunctionTest(MaskFunctionMixin, unittest.TestCase):
+    def mask(self, mask, data):
+        return speedups.websocket_mask(mask, data)
+
+
+class ServerPeriodicPingTest(WebSocketBaseTestCase):
+    def get_app(self):
+        class PingHandler(TestWebSocketHandler):
+            def on_pong(self, data):
+                self.write_message("got pong")
+
+        return Application([("/", PingHandler)], websocket_ping_interval=0.01)
+
+    @gen_test
+    def test_server_ping(self):
+        ws = yield self.ws_connect("/")
+        for i in range(3):
+            response = yield ws.read_message()
+            self.assertEqual(response, "got pong")
+        # TODO: test that the connection gets closed if ping responses stop.
+
+
+class ClientPeriodicPingTest(WebSocketBaseTestCase):
+    def get_app(self):
+        class PingHandler(TestWebSocketHandler):
+            def on_ping(self, data):
+                self.write_message("got ping")
+
+        return Application([("/", PingHandler)])
+
+    @gen_test
+    def test_client_ping(self):
+        ws = yield self.ws_connect("/", ping_interval=0.01)
+        for i in range(3):
+            response = yield ws.read_message()
+            self.assertEqual(response, "got ping")
+        # TODO: test that the connection gets closed if ping responses stop.
+
+
+class ManualPingTest(WebSocketBaseTestCase):
+    def get_app(self):
+        class PingHandler(TestWebSocketHandler):
+            def on_ping(self, data):
+                self.write_message(data, binary=isinstance(data, bytes))
+
+        return Application([("/", PingHandler)])
+
+    @gen_test
+    def test_manual_ping(self):
+        ws = yield self.ws_connect("/")
+
+        self.assertRaises(ValueError, ws.ping, "a" * 126)
+
+        ws.ping("hello")
+        resp = yield ws.read_message()
+        # on_ping always sees bytes.
+        self.assertEqual(resp, b"hello")
+
+        ws.ping(b"binary hello")
+        resp = yield ws.read_message()
+        self.assertEqual(resp, b"binary hello")
+
+
+class MaxMessageSizeTest(WebSocketBaseTestCase):
+    def get_app(self):
+        return Application([("/", EchoHandler)], websocket_max_message_size=1024)
+
+    @gen_test
+    def test_large_message(self):
+        ws = yield self.ws_connect("/")
+
+        # Write a message that is allowed.
+        msg = "a" * 1024
+        ws.write_message(msg)
+        resp = yield ws.read_message()
+        self.assertEqual(resp, msg)
+
+        # Write a message that is too large.
+        ws.write_message(msg + "b")
+        resp = yield ws.read_message()
+        # A message of None means the other side closed the connection.
+        self.assertIs(resp, None)
+        self.assertEqual(ws.close_code, 1009)
+        self.assertEqual(ws.close_reason, "message too big")
+        # TODO: Needs tests of messages split over multiple
+        # continuation frames.
diff --git a/venv/lib/python3.9/site-packages/tornado/test/wsgi_test.py b/venv/lib/python3.9/site-packages/tornado/test/wsgi_test.py
new file mode 100644
index 00000000..9fbc744e
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/test/wsgi_test.py
@@ -0,0 +1,116 @@
+import asyncio
+import concurrent.futures
+import threading
+
+from wsgiref.validate import validator
+
+from tornado.routing import RuleRouter
+from tornado.testing import AsyncHTTPTestCase, gen_test
+from tornado.wsgi import WSGIContainer
+
+
+class WSGIAppMixin:
+    # TODO: Now that WSGIAdapter is gone, this is a pretty weak test.
+    def get_executor(self):
+        raise NotImplementedError()
+
+    def get_app(self):
+        executor = self.get_executor()
+        # The barrier test in DummyExecutorTest will always wait the full
+        # value of this timeout, so we don't want it to be too high.
+        self.barrier = threading.Barrier(2, timeout=0.3)
+
+        def make_container(app):
+            return WSGIContainer(validator(app), executor=executor)
+
+        return RuleRouter(
+            [
+                ("/simple", make_container(self.simple_wsgi_app)),
+                ("/barrier", make_container(self.barrier_wsgi_app)),
+                ("/streaming_barrier", make_container(self.streaming_barrier_wsgi_app)),
+            ]
+        )
+
+    def respond_plain(self, start_response):
+        status = "200 OK"
+        response_headers = [("Content-Type", "text/plain")]
+        start_response(status, response_headers)
+
+    def simple_wsgi_app(self, environ, start_response):
+        self.respond_plain(start_response)
+        return [b"Hello world!"]
+
+    def barrier_wsgi_app(self, environ, start_response):
+        self.respond_plain(start_response)
+        try:
+            n = self.barrier.wait()
+        except threading.BrokenBarrierError:
+            return [b"broken barrier"]
+        else:
+            return [b"ok %d" % n]
+
+    def streaming_barrier_wsgi_app(self, environ, start_response):
+        self.respond_plain(start_response)
+        yield b"ok "
+        try:
+            n = self.barrier.wait()
+        except threading.BrokenBarrierError:
+            yield b"broken barrier"
+        else:
+            yield b"%d" % n
+
+
+class WSGIContainerDummyExecutorTest(WSGIAppMixin, AsyncHTTPTestCase):
+    def get_executor(self):
+        return None
+
+    def test_simple(self):
+        response = self.fetch("/simple")
+        self.assertEqual(response.body, b"Hello world!")
+
+    @gen_test
+    async def test_concurrent_barrier(self):
+        self.barrier.reset()
+        resps = await asyncio.gather(
+            self.http_client.fetch(self.get_url("/barrier")),
+            self.http_client.fetch(self.get_url("/barrier")),
+        )
+        for resp in resps:
+            self.assertEqual(resp.body, b"broken barrier")
+
+    @gen_test
+    async def test_concurrent_streaming_barrier(self):
+        self.barrier.reset()
+        resps = await asyncio.gather(
+            self.http_client.fetch(self.get_url("/streaming_barrier")),
+            self.http_client.fetch(self.get_url("/streaming_barrier")),
+        )
+        for resp in resps:
+            self.assertEqual(resp.body, b"ok broken barrier")
+
+
+class WSGIContainerThreadPoolTest(WSGIAppMixin, AsyncHTTPTestCase):
+    def get_executor(self):
+        return concurrent.futures.ThreadPoolExecutor()
+
+    def test_simple(self):
+        response = self.fetch("/simple")
+        self.assertEqual(response.body, b"Hello world!")
+
+    @gen_test
+    async def test_concurrent_barrier(self):
+        self.barrier.reset()
+        resps = await asyncio.gather(
+            self.http_client.fetch(self.get_url("/barrier")),
+            self.http_client.fetch(self.get_url("/barrier")),
+        )
+        self.assertEqual([b"ok 0", b"ok 1"], sorted([resp.body for resp in resps]))
+
+    @gen_test
+    async def test_concurrent_streaming_barrier(self):
+        self.barrier.reset()
+        resps = await asyncio.gather(
+            self.http_client.fetch(self.get_url("/streaming_barrier")),
+            self.http_client.fetch(self.get_url("/streaming_barrier")),
+        )
+        self.assertEqual([b"ok 0", b"ok 1"], sorted([resp.body for resp in resps]))
diff --git a/venv/lib/python3.9/site-packages/tornado/testing.py b/venv/lib/python3.9/site-packages/tornado/testing.py
new file mode 100644
index 00000000..9bfadf45
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/testing.py
@@ -0,0 +1,872 @@
+"""Support classes for automated testing.
+
+* `AsyncTestCase` and `AsyncHTTPTestCase`:  Subclasses of unittest.TestCase
+  with additional support for testing asynchronous (`.IOLoop`-based) code.
+
+* `ExpectLog`: Make test logs less spammy.
+
+* `main()`: A simple test runner (wrapper around unittest.main()) with support
+  for the tornado.autoreload module to rerun the tests when code changes.
+"""
+
+import asyncio
+from collections.abc import Generator
+import functools
+import inspect
+import logging
+import os
+import re
+import signal
+import socket
+import sys
+import unittest
+import warnings
+
+from tornado import gen
+from tornado.httpclient import AsyncHTTPClient, HTTPResponse
+from tornado.httpserver import HTTPServer
+from tornado.ioloop import IOLoop, TimeoutError
+from tornado import netutil
+from tornado.platform.asyncio import AsyncIOMainLoop
+from tornado.process import Subprocess
+from tornado.log import app_log
+from tornado.util import raise_exc_info, basestring_type
+from tornado.web import Application
+
+import typing
+from typing import Tuple, Any, Callable, Type, Dict, Union, Optional, Coroutine
+from types import TracebackType
+
+if typing.TYPE_CHECKING:
+    _ExcInfoTuple = Tuple[
+        Optional[Type[BaseException]], Optional[BaseException], Optional[TracebackType]
+    ]
+
+
+_NON_OWNED_IOLOOPS = AsyncIOMainLoop
+
+
+def bind_unused_port(
+    reuse_port: bool = False, address: str = "127.0.0.1"
+) -> Tuple[socket.socket, int]:
+    """Binds a server socket to an available port on localhost.
+
+    Returns a tuple (socket, port).
+
+    .. versionchanged:: 4.4
+       Always binds to ``127.0.0.1`` without resolving the name
+       ``localhost``.
+
+    .. versionchanged:: 6.2
+       Added optional ``address`` argument to
+       override the default "127.0.0.1".
+    """
+    sock = netutil.bind_sockets(
+        0, address, family=socket.AF_INET, reuse_port=reuse_port
+    )[0]
+    port = sock.getsockname()[1]
+    return sock, port
+
+
+def get_async_test_timeout() -> float:
+    """Get the global timeout setting for async tests.
+
+    Returns a float, the timeout in seconds.
+
+    .. versionadded:: 3.1
+    """
+    env = os.environ.get("ASYNC_TEST_TIMEOUT")
+    if env is not None:
+        try:
+            return float(env)
+        except ValueError:
+            pass
+    return 5
+
+
+class _TestMethodWrapper(object):
+    """Wraps a test method to raise an error if it returns a value.
+
+    This is mainly used to detect undecorated generators (if a test
+    method yields it must use a decorator to consume the generator),
+    but will also detect other kinds of return values (these are not
+    necessarily errors, but we alert anyway since there is no good
+    reason to return a value from a test).
+    """
+
+    def __init__(self, orig_method: Callable) -> None:
+        self.orig_method = orig_method
+        self.__wrapped__ = orig_method
+
+    def __call__(self, *args: Any, **kwargs: Any) -> None:
+        result = self.orig_method(*args, **kwargs)
+        if isinstance(result, Generator) or inspect.iscoroutine(result):
+            raise TypeError(
+                "Generator and coroutine test methods should be"
+                " decorated with tornado.testing.gen_test"
+            )
+        elif result is not None:
+            raise ValueError("Return value from test method ignored: %r" % result)
+
+    def __getattr__(self, name: str) -> Any:
+        """Proxy all unknown attributes to the original method.
+
+        This is important for some of the decorators in the `unittest`
+        module, such as `unittest.skipIf`.
+        """
+        return getattr(self.orig_method, name)
+
+
+class AsyncTestCase(unittest.TestCase):
+    """`~unittest.TestCase` subclass for testing `.IOLoop`-based
+    asynchronous code.
+
+    The unittest framework is synchronous, so the test must be
+    complete by the time the test method returns. This means that
+    asynchronous code cannot be used in quite the same way as usual
+    and must be adapted to fit. To write your tests with coroutines,
+    decorate your test methods with `tornado.testing.gen_test` instead
+    of `tornado.gen.coroutine`.
+
+    This class also provides the (deprecated) `stop()` and `wait()`
+    methods for a more manual style of testing. The test method itself
+    must call ``self.wait()``, and asynchronous callbacks should call
+    ``self.stop()`` to signal completion.
+
+    By default, a new `.IOLoop` is constructed for each test and is available
+    as ``self.io_loop``.  If the code being tested requires a
+    reused global `.IOLoop`, subclasses should override `get_new_ioloop` to return it,
+    although this is deprecated as of Tornado 6.3.
+
+    The `.IOLoop`'s ``start`` and ``stop`` methods should not be
+    called directly.  Instead, use `self.stop <stop>` and `self.wait
+    <wait>`.  Arguments passed to ``self.stop`` are returned from
+    ``self.wait``.  It is possible to have multiple ``wait``/``stop``
+    cycles in the same test.
+
+    Example::
+
+        # This test uses coroutine style.
+        class MyTestCase(AsyncTestCase):
+            @tornado.testing.gen_test
+            def test_http_fetch(self):
+                client = AsyncHTTPClient()
+                response = yield client.fetch("http://www.tornadoweb.org")
+                # Test contents of response
+                self.assertIn("FriendFeed", response.body)
+
+        # This test uses argument passing between self.stop and self.wait.
+        class MyTestCase2(AsyncTestCase):
+            def test_http_fetch(self):
+                client = AsyncHTTPClient()
+                client.fetch("http://www.tornadoweb.org/", self.stop)
+                response = self.wait()
+                # Test contents of response
+                self.assertIn("FriendFeed", response.body)
+    """
+
+    def __init__(self, methodName: str = "runTest") -> None:
+        super().__init__(methodName)
+        self.__stopped = False
+        self.__running = False
+        self.__failure = None  # type: Optional[_ExcInfoTuple]
+        self.__stop_args = None  # type: Any
+        self.__timeout = None  # type: Optional[object]
+
+        # It's easy to forget the @gen_test decorator, but if you do
+        # the test will silently be ignored because nothing will consume
+        # the generator.  Replace the test method with a wrapper that will
+        # make sure it's not an undecorated generator.
+        setattr(self, methodName, _TestMethodWrapper(getattr(self, methodName)))
+
+        # Not used in this class itself, but used by @gen_test
+        self._test_generator = None  # type: Optional[Union[Generator, Coroutine]]
+
+    def setUp(self) -> None:
+        py_ver = sys.version_info
+        if ((3, 10, 0) <= py_ver < (3, 10, 9)) or ((3, 11, 0) <= py_ver <= (3, 11, 1)):
+            # Early releases in the Python 3.10 and 3.1 series had deprecation
+            # warnings that were later reverted; we must suppress them here.
+            setup_with_context_manager(self, warnings.catch_warnings())
+            warnings.filterwarnings(
+                "ignore",
+                message="There is no current event loop",
+                category=DeprecationWarning,
+                module=r"tornado\..*",
+            )
+        super().setUp()
+        if type(self).get_new_ioloop is not AsyncTestCase.get_new_ioloop:
+            warnings.warn("get_new_ioloop is deprecated", DeprecationWarning)
+        self.io_loop = self.get_new_ioloop()
+        asyncio.set_event_loop(self.io_loop.asyncio_loop)  # type: ignore[attr-defined]
+
+    def tearDown(self) -> None:
+        # Native coroutines tend to produce warnings if they're not
+        # allowed to run to completion. It's difficult to ensure that
+        # this always happens in tests, so cancel any tasks that are
+        # still pending by the time we get here.
+        asyncio_loop = self.io_loop.asyncio_loop  # type: ignore
+        if hasattr(asyncio, "all_tasks"):  # py37
+            tasks = asyncio.all_tasks(asyncio_loop)  # type: ignore
+        else:
+            tasks = asyncio.Task.all_tasks(asyncio_loop)
+        # Tasks that are done may still appear here and may contain
+        # non-cancellation exceptions, so filter them out.
+        tasks = [t for t in tasks if not t.done()]  # type: ignore
+        for t in tasks:
+            t.cancel()
+        # Allow the tasks to run and finalize themselves (which means
+        # raising a CancelledError inside the coroutine). This may
+        # just transform the "task was destroyed but it is pending"
+        # warning into a "uncaught CancelledError" warning, but
+        # catching CancelledErrors in coroutines that may leak is
+        # simpler than ensuring that no coroutines leak.
+        if tasks:
+            done, pending = self.io_loop.run_sync(lambda: asyncio.wait(tasks))
+            assert not pending
+            # If any task failed with anything but a CancelledError, raise it.
+            for f in done:
+                try:
+                    f.result()
+                except asyncio.CancelledError:
+                    pass
+
+        # Clean up Subprocess, so it can be used again with a new ioloop.
+        Subprocess.uninitialize()
+        asyncio.set_event_loop(None)
+        if not isinstance(self.io_loop, _NON_OWNED_IOLOOPS):
+            # Try to clean up any file descriptors left open in the ioloop.
+            # This avoids leaks, especially when tests are run repeatedly
+            # in the same process with autoreload (because curl does not
+            # set FD_CLOEXEC on its file descriptors)
+            self.io_loop.close(all_fds=True)
+        super().tearDown()
+        # In case an exception escaped or the StackContext caught an exception
+        # when there wasn't a wait() to re-raise it, do so here.
+        # This is our last chance to raise an exception in a way that the
+        # unittest machinery understands.
+        self.__rethrow()
+
+    def get_new_ioloop(self) -> IOLoop:
+        """Returns the `.IOLoop` to use for this test.
+
+        By default, a new `.IOLoop` is created for each test.
+        Subclasses may override this method to return
+        `.IOLoop.current()` if it is not appropriate to use a new
+        `.IOLoop` in each tests (for example, if there are global
+        singletons using the default `.IOLoop`) or if a per-test event
+        loop is being provided by another system (such as
+        ``pytest-asyncio``).
+
+        .. deprecated:: 6.3
+           This method will be removed in Tornado 7.0.
+        """
+        return IOLoop(make_current=False)
+
+    def _handle_exception(
+        self, typ: Type[Exception], value: Exception, tb: TracebackType
+    ) -> bool:
+        if self.__failure is None:
+            self.__failure = (typ, value, tb)
+        else:
+            app_log.error(
+                "multiple unhandled exceptions in test", exc_info=(typ, value, tb)
+            )
+        self.stop()
+        return True
+
+    def __rethrow(self) -> None:
+        if self.__failure is not None:
+            failure = self.__failure
+            self.__failure = None
+            raise_exc_info(failure)
+
+    def run(
+        self, result: Optional[unittest.TestResult] = None
+    ) -> Optional[unittest.TestResult]:
+        ret = super().run(result)
+        # As a last resort, if an exception escaped super.run() and wasn't
+        # re-raised in tearDown, raise it here.  This will cause the
+        # unittest run to fail messily, but that's better than silently
+        # ignoring an error.
+        self.__rethrow()
+        return ret
+
+    def stop(self, _arg: Any = None, **kwargs: Any) -> None:
+        """Stops the `.IOLoop`, causing one pending (or future) call to `wait()`
+        to return.
+
+        Keyword arguments or a single positional argument passed to `stop()` are
+        saved and will be returned by `wait()`.
+
+        .. deprecated:: 5.1
+
+           `stop` and `wait` are deprecated; use ``@gen_test`` instead.
+        """
+        assert _arg is None or not kwargs
+        self.__stop_args = kwargs or _arg
+        if self.__running:
+            self.io_loop.stop()
+            self.__running = False
+        self.__stopped = True
+
+    def wait(
+        self,
+        condition: Optional[Callable[..., bool]] = None,
+        timeout: Optional[float] = None,
+    ) -> Any:
+        """Runs the `.IOLoop` until stop is called or timeout has passed.
+
+        In the event of a timeout, an exception will be thrown. The
+        default timeout is 5 seconds; it may be overridden with a
+        ``timeout`` keyword argument or globally with the
+        ``ASYNC_TEST_TIMEOUT`` environment variable.
+
+        If ``condition`` is not ``None``, the `.IOLoop` will be restarted
+        after `stop()` until ``condition()`` returns ``True``.
+
+        .. versionchanged:: 3.1
+           Added the ``ASYNC_TEST_TIMEOUT`` environment variable.
+
+        .. deprecated:: 5.1
+
+           `stop` and `wait` are deprecated; use ``@gen_test`` instead.
+        """
+        if timeout is None:
+            timeout = get_async_test_timeout()
+
+        if not self.__stopped:
+            if timeout:
+
+                def timeout_func() -> None:
+                    try:
+                        raise self.failureException(
+                            "Async operation timed out after %s seconds" % timeout
+                        )
+                    except Exception:
+                        self.__failure = sys.exc_info()
+                    self.stop()
+
+                self.__timeout = self.io_loop.add_timeout(
+                    self.io_loop.time() + timeout, timeout_func
+                )
+            while True:
+                self.__running = True
+                self.io_loop.start()
+                if self.__failure is not None or condition is None or condition():
+                    break
+            if self.__timeout is not None:
+                self.io_loop.remove_timeout(self.__timeout)
+                self.__timeout = None
+        assert self.__stopped
+        self.__stopped = False
+        self.__rethrow()
+        result = self.__stop_args
+        self.__stop_args = None
+        return result
+
+
+class AsyncHTTPTestCase(AsyncTestCase):
+    """A test case that starts up an HTTP server.
+
+    Subclasses must override `get_app()`, which returns the
+    `tornado.web.Application` (or other `.HTTPServer` callback) to be tested.
+    Tests will typically use the provided ``self.http_client`` to fetch
+    URLs from this server.
+
+    Example, assuming the "Hello, world" example from the user guide is in
+    ``hello.py``::
+
+        import hello
+
+        class TestHelloApp(AsyncHTTPTestCase):
+            def get_app(self):
+                return hello.make_app()
+
+            def test_homepage(self):
+                response = self.fetch('/')
+                self.assertEqual(response.code, 200)
+                self.assertEqual(response.body, 'Hello, world')
+
+    That call to ``self.fetch()`` is equivalent to ::
+
+        self.http_client.fetch(self.get_url('/'), self.stop)
+        response = self.wait()
+
+    which illustrates how AsyncTestCase can turn an asynchronous operation,
+    like ``http_client.fetch()``, into a synchronous operation. If you need
+    to do other asynchronous operations in tests, you'll probably need to use
+    ``stop()`` and ``wait()`` yourself.
+    """
+
+    def setUp(self) -> None:
+        super().setUp()
+        sock, port = bind_unused_port()
+        self.__port = port
+
+        self.http_client = self.get_http_client()
+        self._app = self.get_app()
+        self.http_server = self.get_http_server()
+        self.http_server.add_sockets([sock])
+
+    def get_http_client(self) -> AsyncHTTPClient:
+        return AsyncHTTPClient()
+
+    def get_http_server(self) -> HTTPServer:
+        return HTTPServer(self._app, **self.get_httpserver_options())
+
+    def get_app(self) -> Application:
+        """Should be overridden by subclasses to return a
+        `tornado.web.Application` or other `.HTTPServer` callback.
+        """
+        raise NotImplementedError()
+
+    def fetch(
+        self, path: str, raise_error: bool = False, **kwargs: Any
+    ) -> HTTPResponse:
+        """Convenience method to synchronously fetch a URL.
+
+        The given path will be appended to the local server's host and
+        port.  Any additional keyword arguments will be passed directly to
+        `.AsyncHTTPClient.fetch` (and so could be used to pass
+        ``method="POST"``, ``body="..."``, etc).
+
+        If the path begins with http:// or https://, it will be treated as a
+        full URL and will be fetched as-is.
+
+        If ``raise_error`` is ``True``, a `tornado.httpclient.HTTPError` will
+        be raised if the response code is not 200. This is the same behavior
+        as the ``raise_error`` argument to `.AsyncHTTPClient.fetch`, but
+        the default is ``False`` here (it's ``True`` in `.AsyncHTTPClient`)
+        because tests often need to deal with non-200 response codes.
+
+        .. versionchanged:: 5.0
+           Added support for absolute URLs.
+
+        .. versionchanged:: 5.1
+
+           Added the ``raise_error`` argument.
+
+        .. deprecated:: 5.1
+
+           This method currently turns any exception into an
+           `.HTTPResponse` with status code 599. In Tornado 6.0,
+           errors other than `tornado.httpclient.HTTPError` will be
+           passed through, and ``raise_error=False`` will only
+           suppress errors that would be raised due to non-200
+           response codes.
+
+        """
+        if path.lower().startswith(("http://", "https://")):
+            url = path
+        else:
+            url = self.get_url(path)
+        return self.io_loop.run_sync(
+            lambda: self.http_client.fetch(url, raise_error=raise_error, **kwargs),
+            timeout=get_async_test_timeout(),
+        )
+
+    def get_httpserver_options(self) -> Dict[str, Any]:
+        """May be overridden by subclasses to return additional
+        keyword arguments for the server.
+        """
+        return {}
+
+    def get_http_port(self) -> int:
+        """Returns the port used by the server.
+
+        A new port is chosen for each test.
+        """
+        return self.__port
+
+    def get_protocol(self) -> str:
+        return "http"
+
+    def get_url(self, path: str) -> str:
+        """Returns an absolute url for the given path on the test server."""
+        return "%s://127.0.0.1:%s%s" % (self.get_protocol(), self.get_http_port(), path)
+
+    def tearDown(self) -> None:
+        self.http_server.stop()
+        self.io_loop.run_sync(
+            self.http_server.close_all_connections, timeout=get_async_test_timeout()
+        )
+        self.http_client.close()
+        del self.http_server
+        del self._app
+        super().tearDown()
+
+
+class AsyncHTTPSTestCase(AsyncHTTPTestCase):
+    """A test case that starts an HTTPS server.
+
+    Interface is generally the same as `AsyncHTTPTestCase`.
+    """
+
+    def get_http_client(self) -> AsyncHTTPClient:
+        return AsyncHTTPClient(force_instance=True, defaults=dict(validate_cert=False))
+
+    def get_httpserver_options(self) -> Dict[str, Any]:
+        return dict(ssl_options=self.get_ssl_options())
+
+    def get_ssl_options(self) -> Dict[str, Any]:
+        """May be overridden by subclasses to select SSL options.
+
+        By default includes a self-signed testing certificate.
+        """
+        return AsyncHTTPSTestCase.default_ssl_options()
+
+    @staticmethod
+    def default_ssl_options() -> Dict[str, Any]:
+        # Testing keys were generated with:
+        # openssl req -new -keyout tornado/test/test.key \
+        #                     -out tornado/test/test.crt -nodes -days 3650 -x509
+        module_dir = os.path.dirname(__file__)
+        return dict(
+            certfile=os.path.join(module_dir, "test", "test.crt"),
+            keyfile=os.path.join(module_dir, "test", "test.key"),
+        )
+
+    def get_protocol(self) -> str:
+        return "https"
+
+
+@typing.overload
+def gen_test(
+    *, timeout: Optional[float] = None
+) -> Callable[[Callable[..., Union[Generator, "Coroutine"]]], Callable[..., None]]:
+    pass
+
+
+@typing.overload  # noqa: F811
+def gen_test(func: Callable[..., Union[Generator, "Coroutine"]]) -> Callable[..., None]:
+    pass
+
+
+def gen_test(  # noqa: F811
+    func: Optional[Callable[..., Union[Generator, "Coroutine"]]] = None,
+    timeout: Optional[float] = None,
+) -> Union[
+    Callable[..., None],
+    Callable[[Callable[..., Union[Generator, "Coroutine"]]], Callable[..., None]],
+]:
+    """Testing equivalent of ``@gen.coroutine``, to be applied to test methods.
+
+    ``@gen.coroutine`` cannot be used on tests because the `.IOLoop` is not
+    already running.  ``@gen_test`` should be applied to test methods
+    on subclasses of `AsyncTestCase`.
+
+    Example::
+
+        class MyTest(AsyncHTTPTestCase):
+            @gen_test
+            def test_something(self):
+                response = yield self.http_client.fetch(self.get_url('/'))
+
+    By default, ``@gen_test`` times out after 5 seconds. The timeout may be
+    overridden globally with the ``ASYNC_TEST_TIMEOUT`` environment variable,
+    or for each test with the ``timeout`` keyword argument::
+
+        class MyTest(AsyncHTTPTestCase):
+            @gen_test(timeout=10)
+            def test_something_slow(self):
+                response = yield self.http_client.fetch(self.get_url('/'))
+
+    Note that ``@gen_test`` is incompatible with `AsyncTestCase.stop`,
+    `AsyncTestCase.wait`, and `AsyncHTTPTestCase.fetch`. Use ``yield
+    self.http_client.fetch(self.get_url())`` as shown above instead.
+
+    .. versionadded:: 3.1
+       The ``timeout`` argument and ``ASYNC_TEST_TIMEOUT`` environment
+       variable.
+
+    .. versionchanged:: 4.0
+       The wrapper now passes along ``*args, **kwargs`` so it can be used
+       on functions with arguments.
+
+    """
+    if timeout is None:
+        timeout = get_async_test_timeout()
+
+    def wrap(f: Callable[..., Union[Generator, "Coroutine"]]) -> Callable[..., None]:
+        # Stack up several decorators to allow us to access the generator
+        # object itself.  In the innermost wrapper, we capture the generator
+        # and save it in an attribute of self.  Next, we run the wrapped
+        # function through @gen.coroutine.  Finally, the coroutine is
+        # wrapped again to make it synchronous with run_sync.
+        #
+        # This is a good case study arguing for either some sort of
+        # extensibility in the gen decorators or cancellation support.
+        @functools.wraps(f)
+        def pre_coroutine(self, *args, **kwargs):
+            # type: (AsyncTestCase, *Any, **Any) -> Union[Generator, Coroutine]
+            # Type comments used to avoid pypy3 bug.
+            result = f(self, *args, **kwargs)
+            if isinstance(result, Generator) or inspect.iscoroutine(result):
+                self._test_generator = result
+            else:
+                self._test_generator = None
+            return result
+
+        if inspect.iscoroutinefunction(f):
+            coro = pre_coroutine
+        else:
+            coro = gen.coroutine(pre_coroutine)  # type: ignore[assignment]
+
+        @functools.wraps(coro)
+        def post_coroutine(self, *args, **kwargs):
+            # type: (AsyncTestCase, *Any, **Any) -> None
+            try:
+                return self.io_loop.run_sync(
+                    functools.partial(coro, self, *args, **kwargs), timeout=timeout
+                )
+            except TimeoutError as e:
+                # run_sync raises an error with an unhelpful traceback.
+                # If the underlying generator is still running, we can throw the
+                # exception back into it so the stack trace is replaced by the
+                # point where the test is stopped. The only reason the generator
+                # would not be running would be if it were cancelled, which means
+                # a native coroutine, so we can rely on the cr_running attribute.
+                if self._test_generator is not None and getattr(
+                    self._test_generator, "cr_running", True
+                ):
+                    self._test_generator.throw(e)
+                    # In case the test contains an overly broad except
+                    # clause, we may get back here.
+                # Coroutine was stopped or didn't raise a useful stack trace,
+                # so re-raise the original exception which is better than nothing.
+                raise
+
+        return post_coroutine
+
+    if func is not None:
+        # Used like:
+        #     @gen_test
+        #     def f(self):
+        #         pass
+        return wrap(func)
+    else:
+        # Used like @gen_test(timeout=10)
+        return wrap
+
+
+# Without this attribute, nosetests will try to run gen_test as a test
+# anywhere it is imported.
+gen_test.__test__ = False  # type: ignore
+
+
+class ExpectLog(logging.Filter):
+    """Context manager to capture and suppress expected log output.
+
+    Useful to make tests of error conditions less noisy, while still
+    leaving unexpected log entries visible.  *Not thread safe.*
+
+    The attribute ``logged_stack`` is set to ``True`` if any exception
+    stack trace was logged.
+
+    Usage::
+
+        with ExpectLog('tornado.application', "Uncaught exception"):
+            error_response = self.fetch("/some_page")
+
+    .. versionchanged:: 4.3
+       Added the ``logged_stack`` attribute.
+    """
+
+    def __init__(
+        self,
+        logger: Union[logging.Logger, basestring_type],
+        regex: str,
+        required: bool = True,
+        level: Optional[int] = None,
+    ) -> None:
+        """Constructs an ExpectLog context manager.
+
+        :param logger: Logger object (or name of logger) to watch.  Pass an
+            empty string to watch the root logger.
+        :param regex: Regular expression to match.  Any log entries on the
+            specified logger that match this regex will be suppressed.
+        :param required: If true, an exception will be raised if the end of the
+            ``with`` statement is reached without matching any log entries.
+        :param level: A constant from the ``logging`` module indicating the
+            expected log level. If this parameter is provided, only log messages
+            at this level will be considered to match. Additionally, the
+            supplied ``logger`` will have its level adjusted if necessary (for
+            the duration of the ``ExpectLog`` to enable the expected message.
+
+        .. versionchanged:: 6.1
+           Added the ``level`` parameter.
+
+        .. deprecated:: 6.3
+           In Tornado 7.0, only ``WARNING`` and higher logging levels will be
+           matched by default. To match ``INFO`` and lower levels, the ``level``
+           argument must be used. This is changing to minimize differences
+           between ``tornado.testing.main`` (which enables ``INFO`` logs by
+           default) and most other test runners (including those in IDEs)
+           which have ``INFO`` logs disabled by default.
+        """
+        if isinstance(logger, basestring_type):
+            logger = logging.getLogger(logger)
+        self.logger = logger
+        self.regex = re.compile(regex)
+        self.required = required
+        # matched and deprecated_level_matched are a counter for the respective event.
+        self.matched = 0
+        self.deprecated_level_matched = 0
+        self.logged_stack = False
+        self.level = level
+        self.orig_level = None  # type: Optional[int]
+
+    def filter(self, record: logging.LogRecord) -> bool:
+        if record.exc_info:
+            self.logged_stack = True
+        message = record.getMessage()
+        if self.regex.match(message):
+            if self.level is None and record.levelno < logging.WARNING:
+                # We're inside the logging machinery here so generating a DeprecationWarning
+                # here won't be reported cleanly (if warnings-as-errors is enabled, the error
+                # just gets swallowed by the logging module), and even if it were it would
+                # have the wrong stack trace. Just remember this fact and report it in
+                # __exit__ instead.
+                self.deprecated_level_matched += 1
+            if self.level is not None and record.levelno != self.level:
+                app_log.warning(
+                    "Got expected log message %r at unexpected level (%s vs %s)"
+                    % (message, logging.getLevelName(self.level), record.levelname)
+                )
+                return True
+            self.matched += 1
+            return False
+        return True
+
+    def __enter__(self) -> "ExpectLog":
+        if self.level is not None and self.level < self.logger.getEffectiveLevel():
+            self.orig_level = self.logger.level
+            self.logger.setLevel(self.level)
+        self.logger.addFilter(self)
+        return self
+
+    def __exit__(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[TracebackType],
+    ) -> None:
+        if self.orig_level is not None:
+            self.logger.setLevel(self.orig_level)
+        self.logger.removeFilter(self)
+        if not typ and self.required and not self.matched:
+            raise Exception("did not get expected log message")
+        if (
+            not typ
+            and self.required
+            and (self.deprecated_level_matched >= self.matched)
+        ):
+            warnings.warn(
+                "ExpectLog matched at INFO or below without level argument",
+                DeprecationWarning,
+            )
+
+
+# From https://nedbatchelder.com/blog/201508/using_context_managers_in_test_setup.html
+def setup_with_context_manager(testcase: unittest.TestCase, cm: Any) -> Any:
+    """Use a contextmanager to setUp a test case."""
+    val = cm.__enter__()
+    testcase.addCleanup(cm.__exit__, None, None, None)
+    return val
+
+
+def main(**kwargs: Any) -> None:
+    """A simple test runner.
+
+    This test runner is essentially equivalent to `unittest.main` from
+    the standard library, but adds support for Tornado-style option
+    parsing and log formatting. It is *not* necessary to use this
+    `main` function to run tests using `AsyncTestCase`; these tests
+    are self-contained and can run with any test runner.
+
+    The easiest way to run a test is via the command line::
+
+        python -m tornado.testing tornado.test.web_test
+
+    See the standard library ``unittest`` module for ways in which
+    tests can be specified.
+
+    Projects with many tests may wish to define a test script like
+    ``tornado/test/runtests.py``.  This script should define a method
+    ``all()`` which returns a test suite and then call
+    `tornado.testing.main()`.  Note that even when a test script is
+    used, the ``all()`` test suite may be overridden by naming a
+    single test on the command line::
+
+        # Runs all tests
+        python -m tornado.test.runtests
+        # Runs one test
+        python -m tornado.test.runtests tornado.test.web_test
+
+    Additional keyword arguments passed through to ``unittest.main()``.
+    For example, use ``tornado.testing.main(verbosity=2)``
+    to show many test details as they are run.
+    See http://docs.python.org/library/unittest.html#unittest.main
+    for full argument list.
+
+    .. versionchanged:: 5.0
+
+       This function produces no output of its own; only that produced
+       by the `unittest` module (previously it would add a PASS or FAIL
+       log message).
+    """
+    from tornado.options import define, options, parse_command_line
+
+    define(
+        "exception_on_interrupt",
+        type=bool,
+        default=True,
+        help=(
+            "If true (default), ctrl-c raises a KeyboardInterrupt "
+            "exception.  This prints a stack trace but cannot interrupt "
+            "certain operations.  If false, the process is more reliably "
+            "killed, but does not print a stack trace."
+        ),
+    )
+
+    # support the same options as unittest's command-line interface
+    define("verbose", type=bool)
+    define("quiet", type=bool)
+    define("failfast", type=bool)
+    define("catch", type=bool)
+    define("buffer", type=bool)
+
+    argv = [sys.argv[0]] + parse_command_line(sys.argv)
+
+    if not options.exception_on_interrupt:
+        signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+    if options.verbose is not None:
+        kwargs["verbosity"] = 2
+    if options.quiet is not None:
+        kwargs["verbosity"] = 0
+    if options.failfast is not None:
+        kwargs["failfast"] = True
+    if options.catch is not None:
+        kwargs["catchbreak"] = True
+    if options.buffer is not None:
+        kwargs["buffer"] = True
+
+    if __name__ == "__main__" and len(argv) == 1:
+        print("No tests specified", file=sys.stderr)
+        sys.exit(1)
+    # In order to be able to run tests by their fully-qualified name
+    # on the command line without importing all tests here,
+    # module must be set to None.  Python 3.2's unittest.main ignores
+    # defaultTest if no module is given (it tries to do its own
+    # test discovery, which is incompatible with auto2to3), so don't
+    # set module if we're not asking for a specific test.
+    if len(argv) > 1:
+        unittest.main(module=None, argv=argv, **kwargs)  # type: ignore
+    else:
+        unittest.main(defaultTest="all", argv=argv, **kwargs)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/venv/lib/python3.9/site-packages/tornado/util.py b/venv/lib/python3.9/site-packages/tornado/util.py
new file mode 100644
index 00000000..3a3a52f1
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/util.py
@@ -0,0 +1,462 @@
+"""Miscellaneous utility functions and classes.
+
+This module is used internally by Tornado.  It is not necessarily expected
+that the functions and classes defined here will be useful to other
+applications, but they are documented here in case they are.
+
+The one public-facing part of this module is the `Configurable` class
+and its `~Configurable.configure` method, which becomes a part of the
+interface of its subclasses, including `.AsyncHTTPClient`, `.IOLoop`,
+and `.Resolver`.
+"""
+
+import array
+import asyncio
+import atexit
+from inspect import getfullargspec
+import os
+import re
+import typing
+import zlib
+
+from typing import (
+    Any,
+    Optional,
+    Dict,
+    Mapping,
+    List,
+    Tuple,
+    Match,
+    Callable,
+    Type,
+    Sequence,
+)
+
+if typing.TYPE_CHECKING:
+    # Additional imports only used in type comments.
+    # This lets us make these imports lazy.
+    import datetime  # noqa: F401
+    from types import TracebackType  # noqa: F401
+    from typing import Union  # noqa: F401
+    import unittest  # noqa: F401
+
+# Aliases for types that are spelled differently in different Python
+# versions. bytes_type is deprecated and no longer used in Tornado
+# itself but is left in case anyone outside Tornado is using it.
+bytes_type = bytes
+unicode_type = str
+basestring_type = str
+
+try:
+    from sys import is_finalizing
+except ImportError:
+    # Emulate it
+    def _get_emulated_is_finalizing() -> Callable[[], bool]:
+        L = []  # type: List[None]
+        atexit.register(lambda: L.append(None))
+
+        def is_finalizing() -> bool:
+            # Not referencing any globals here
+            return L != []
+
+        return is_finalizing
+
+    is_finalizing = _get_emulated_is_finalizing()
+
+
+# versionchanged:: 6.2
+# no longer our own TimeoutError, use standard asyncio class
+TimeoutError = asyncio.TimeoutError
+
+
+class ObjectDict(Dict[str, Any]):
+    """Makes a dictionary behave like an object, with attribute-style access."""
+
+    def __getattr__(self, name: str) -> Any:
+        try:
+            return self[name]
+        except KeyError:
+            raise AttributeError(name)
+
+    def __setattr__(self, name: str, value: Any) -> None:
+        self[name] = value
+
+
+class GzipDecompressor(object):
+    """Streaming gzip decompressor.
+
+    The interface is like that of `zlib.decompressobj` (without some of the
+    optional arguments, but it understands gzip headers and checksums.
+    """
+
+    def __init__(self) -> None:
+        # Magic parameter makes zlib module understand gzip header
+        # http://stackoverflow.com/questions/1838699/how-can-i-decompress-a-gzip-stream-with-zlib
+        # This works on cpython and pypy, but not jython.
+        self.decompressobj = zlib.decompressobj(16 + zlib.MAX_WBITS)
+
+    def decompress(self, value: bytes, max_length: int = 0) -> bytes:
+        """Decompress a chunk, returning newly-available data.
+
+        Some data may be buffered for later processing; `flush` must
+        be called when there is no more input data to ensure that
+        all data was processed.
+
+        If ``max_length`` is given, some input data may be left over
+        in ``unconsumed_tail``; you must retrieve this value and pass
+        it back to a future call to `decompress` if it is not empty.
+        """
+        return self.decompressobj.decompress(value, max_length)
+
+    @property
+    def unconsumed_tail(self) -> bytes:
+        """Returns the unconsumed portion left over"""
+        return self.decompressobj.unconsumed_tail
+
+    def flush(self) -> bytes:
+        """Return any remaining buffered data not yet returned by decompress.
+
+        Also checks for errors such as truncated input.
+        No other methods may be called on this object after `flush`.
+        """
+        return self.decompressobj.flush()
+
+
+def import_object(name: str) -> Any:
+    """Imports an object by name.
+
+    ``import_object('x')`` is equivalent to ``import x``.
+    ``import_object('x.y.z')`` is equivalent to ``from x.y import z``.
+
+    >>> import tornado.escape
+    >>> import_object('tornado.escape') is tornado.escape
+    True
+    >>> import_object('tornado.escape.utf8') is tornado.escape.utf8
+    True
+    >>> import_object('tornado') is tornado
+    True
+    >>> import_object('tornado.missing_module')
+    Traceback (most recent call last):
+        ...
+    ImportError: No module named missing_module
+    """
+    if name.count(".") == 0:
+        return __import__(name)
+
+    parts = name.split(".")
+    obj = __import__(".".join(parts[:-1]), fromlist=[parts[-1]])
+    try:
+        return getattr(obj, parts[-1])
+    except AttributeError:
+        raise ImportError("No module named %s" % parts[-1])
+
+
+def exec_in(
+    code: Any, glob: Dict[str, Any], loc: Optional[Optional[Mapping[str, Any]]] = None
+) -> None:
+    if isinstance(code, str):
+        # exec(string) inherits the caller's future imports; compile
+        # the string first to prevent that.
+        code = compile(code, "<string>", "exec", dont_inherit=True)
+    exec(code, glob, loc)
+
+
+def raise_exc_info(
+    exc_info: Tuple[Optional[type], Optional[BaseException], Optional["TracebackType"]]
+) -> typing.NoReturn:
+    try:
+        if exc_info[1] is not None:
+            raise exc_info[1].with_traceback(exc_info[2])
+        else:
+            raise TypeError("raise_exc_info called with no exception")
+    finally:
+        # Clear the traceback reference from our stack frame to
+        # minimize circular references that slow down GC.
+        exc_info = (None, None, None)
+
+
+def errno_from_exception(e: BaseException) -> Optional[int]:
+    """Provides the errno from an Exception object.
+
+    There are cases that the errno attribute was not set so we pull
+    the errno out of the args but if someone instantiates an Exception
+    without any args you will get a tuple error. So this function
+    abstracts all that behavior to give you a safe way to get the
+    errno.
+    """
+
+    if hasattr(e, "errno"):
+        return e.errno  # type: ignore
+    elif e.args:
+        return e.args[0]
+    else:
+        return None
+
+
+_alphanum = frozenset("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
+
+
+def _re_unescape_replacement(match: Match[str]) -> str:
+    group = match.group(1)
+    if group[0] in _alphanum:
+        raise ValueError("cannot unescape '\\\\%s'" % group[0])
+    return group
+
+
+_re_unescape_pattern = re.compile(r"\\(.)", re.DOTALL)
+
+
+def re_unescape(s: str) -> str:
+    r"""Unescape a string escaped by `re.escape`.
+
+    May raise ``ValueError`` for regular expressions which could not
+    have been produced by `re.escape` (for example, strings containing
+    ``\d`` cannot be unescaped).
+
+    .. versionadded:: 4.4
+    """
+    return _re_unescape_pattern.sub(_re_unescape_replacement, s)
+
+
+class Configurable(object):
+    """Base class for configurable interfaces.
+
+    A configurable interface is an (abstract) class whose constructor
+    acts as a factory function for one of its implementation subclasses.
+    The implementation subclass as well as optional keyword arguments to
+    its initializer can be set globally at runtime with `configure`.
+
+    By using the constructor as the factory method, the interface
+    looks like a normal class, `isinstance` works as usual, etc.  This
+    pattern is most useful when the choice of implementation is likely
+    to be a global decision (e.g. when `~select.epoll` is available,
+    always use it instead of `~select.select`), or when a
+    previously-monolithic class has been split into specialized
+    subclasses.
+
+    Configurable subclasses must define the class methods
+    `configurable_base` and `configurable_default`, and use the instance
+    method `initialize` instead of ``__init__``.
+
+    .. versionchanged:: 5.0
+
+       It is now possible for configuration to be specified at
+       multiple levels of a class hierarchy.
+
+    """
+
+    # Type annotations on this class are mostly done with comments
+    # because they need to refer to Configurable, which isn't defined
+    # until after the class definition block. These can use regular
+    # annotations when our minimum python version is 3.7.
+    #
+    # There may be a clever way to use generics here to get more
+    # precise types (i.e. for a particular Configurable subclass T,
+    # all the types are subclasses of T, not just Configurable).
+    __impl_class = None  # type: Optional[Type[Configurable]]
+    __impl_kwargs = None  # type: Dict[str, Any]
+
+    def __new__(cls, *args: Any, **kwargs: Any) -> Any:
+        base = cls.configurable_base()
+        init_kwargs = {}  # type: Dict[str, Any]
+        if cls is base:
+            impl = cls.configured_class()
+            if base.__impl_kwargs:
+                init_kwargs.update(base.__impl_kwargs)
+        else:
+            impl = cls
+        init_kwargs.update(kwargs)
+        if impl.configurable_base() is not base:
+            # The impl class is itself configurable, so recurse.
+            return impl(*args, **init_kwargs)
+        instance = super(Configurable, cls).__new__(impl)
+        # initialize vs __init__ chosen for compatibility with AsyncHTTPClient
+        # singleton magic.  If we get rid of that we can switch to __init__
+        # here too.
+        instance.initialize(*args, **init_kwargs)
+        return instance
+
+    @classmethod
+    def configurable_base(cls):
+        # type: () -> Type[Configurable]
+        """Returns the base class of a configurable hierarchy.
+
+        This will normally return the class in which it is defined.
+        (which is *not* necessarily the same as the ``cls`` classmethod
+        parameter).
+
+        """
+        raise NotImplementedError()
+
+    @classmethod
+    def configurable_default(cls):
+        # type: () -> Type[Configurable]
+        """Returns the implementation class to be used if none is configured."""
+        raise NotImplementedError()
+
+    def _initialize(self) -> None:
+        pass
+
+    initialize = _initialize  # type: Callable[..., None]
+    """Initialize a `Configurable` subclass instance.
+
+    Configurable classes should use `initialize` instead of ``__init__``.
+
+    .. versionchanged:: 4.2
+       Now accepts positional arguments in addition to keyword arguments.
+    """
+
+    @classmethod
+    def configure(cls, impl, **kwargs):
+        # type: (Union[None, str, Type[Configurable]], Any) -> None
+        """Sets the class to use when the base class is instantiated.
+
+        Keyword arguments will be saved and added to the arguments passed
+        to the constructor.  This can be used to set global defaults for
+        some parameters.
+        """
+        base = cls.configurable_base()
+        if isinstance(impl, str):
+            impl = typing.cast(Type[Configurable], import_object(impl))
+        if impl is not None and not issubclass(impl, cls):
+            raise ValueError("Invalid subclass of %s" % cls)
+        base.__impl_class = impl
+        base.__impl_kwargs = kwargs
+
+    @classmethod
+    def configured_class(cls):
+        # type: () -> Type[Configurable]
+        """Returns the currently configured class."""
+        base = cls.configurable_base()
+        # Manually mangle the private name to see whether this base
+        # has been configured (and not another base higher in the
+        # hierarchy).
+        if base.__dict__.get("_Configurable__impl_class") is None:
+            base.__impl_class = cls.configurable_default()
+        if base.__impl_class is not None:
+            return base.__impl_class
+        else:
+            # Should be impossible, but mypy wants an explicit check.
+            raise ValueError("configured class not found")
+
+    @classmethod
+    def _save_configuration(cls):
+        # type: () -> Tuple[Optional[Type[Configurable]], Dict[str, Any]]
+        base = cls.configurable_base()
+        return (base.__impl_class, base.__impl_kwargs)
+
+    @classmethod
+    def _restore_configuration(cls, saved):
+        # type: (Tuple[Optional[Type[Configurable]], Dict[str, Any]]) -> None
+        base = cls.configurable_base()
+        base.__impl_class = saved[0]
+        base.__impl_kwargs = saved[1]
+
+
+class ArgReplacer(object):
+    """Replaces one value in an ``args, kwargs`` pair.
+
+    Inspects the function signature to find an argument by name
+    whether it is passed by position or keyword.  For use in decorators
+    and similar wrappers.
+    """
+
+    def __init__(self, func: Callable, name: str) -> None:
+        self.name = name
+        try:
+            self.arg_pos = self._getargnames(func).index(name)  # type: Optional[int]
+        except ValueError:
+            # Not a positional parameter
+            self.arg_pos = None
+
+    def _getargnames(self, func: Callable) -> List[str]:
+        try:
+            return getfullargspec(func).args
+        except TypeError:
+            if hasattr(func, "func_code"):
+                # Cython-generated code has all the attributes needed
+                # by inspect.getfullargspec, but the inspect module only
+                # works with ordinary functions. Inline the portion of
+                # getfullargspec that we need here. Note that for static
+                # functions the @cython.binding(True) decorator must
+                # be used (for methods it works out of the box).
+                code = func.func_code  # type: ignore
+                return code.co_varnames[: code.co_argcount]
+            raise
+
+    def get_old_value(
+        self, args: Sequence[Any], kwargs: Dict[str, Any], default: Any = None
+    ) -> Any:
+        """Returns the old value of the named argument without replacing it.
+
+        Returns ``default`` if the argument is not present.
+        """
+        if self.arg_pos is not None and len(args) > self.arg_pos:
+            return args[self.arg_pos]
+        else:
+            return kwargs.get(self.name, default)
+
+    def replace(
+        self, new_value: Any, args: Sequence[Any], kwargs: Dict[str, Any]
+    ) -> Tuple[Any, Sequence[Any], Dict[str, Any]]:
+        """Replace the named argument in ``args, kwargs`` with ``new_value``.
+
+        Returns ``(old_value, args, kwargs)``.  The returned ``args`` and
+        ``kwargs`` objects may not be the same as the input objects, or
+        the input objects may be mutated.
+
+        If the named argument was not found, ``new_value`` will be added
+        to ``kwargs`` and None will be returned as ``old_value``.
+        """
+        if self.arg_pos is not None and len(args) > self.arg_pos:
+            # The arg to replace is passed positionally
+            old_value = args[self.arg_pos]
+            args = list(args)  # *args is normally a tuple
+            args[self.arg_pos] = new_value
+        else:
+            # The arg to replace is either omitted or passed by keyword.
+            old_value = kwargs.get(self.name)
+            kwargs[self.name] = new_value
+        return old_value, args, kwargs
+
+
+def timedelta_to_seconds(td):
+    # type: (datetime.timedelta) -> float
+    """Equivalent to ``td.total_seconds()`` (introduced in Python 2.7)."""
+    return td.total_seconds()
+
+
+def _websocket_mask_python(mask: bytes, data: bytes) -> bytes:
+    """Websocket masking function.
+
+    `mask` is a `bytes` object of length 4; `data` is a `bytes` object of any length.
+    Returns a `bytes` object of the same length as `data` with the mask applied
+    as specified in section 5.3 of RFC 6455.
+
+    This pure-python implementation may be replaced by an optimized version when available.
+    """
+    mask_arr = array.array("B", mask)
+    unmasked_arr = array.array("B", data)
+    for i in range(len(data)):
+        unmasked_arr[i] = unmasked_arr[i] ^ mask_arr[i % 4]
+    return unmasked_arr.tobytes()
+
+
+if os.environ.get("TORNADO_NO_EXTENSION") or os.environ.get("TORNADO_EXTENSION") == "0":
+    # These environment variables exist to make it easier to do performance
+    # comparisons; they are not guaranteed to remain supported in the future.
+    _websocket_mask = _websocket_mask_python
+else:
+    try:
+        from tornado.speedups import websocket_mask as _websocket_mask
+    except ImportError:
+        if os.environ.get("TORNADO_EXTENSION") == "1":
+            raise
+        _websocket_mask = _websocket_mask_python
+
+
+def doctests():
+    # type: () -> unittest.TestSuite
+    import doctest
+
+    return doctest.DocTestSuite()
diff --git a/venv/lib/python3.9/site-packages/tornado/web.py b/venv/lib/python3.9/site-packages/tornado/web.py
new file mode 100644
index 00000000..3b676e3c
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/web.py
@@ -0,0 +1,3696 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""``tornado.web`` provides a simple web framework with asynchronous
+features that allow it to scale to large numbers of open connections,
+making it ideal for `long polling
+<http://en.wikipedia.org/wiki/Push_technology#Long_polling>`_.
+
+Here is a simple "Hello, world" example app:
+
+.. testcode::
+
+    import asyncio
+    import tornado
+
+    class MainHandler(tornado.web.RequestHandler):
+        def get(self):
+            self.write("Hello, world")
+
+    async def main():
+        application = tornado.web.Application([
+            (r"/", MainHandler),
+        ])
+        application.listen(8888)
+        await asyncio.Event().wait()
+
+    if __name__ == "__main__":
+        asyncio.run(main())
+
+.. testoutput::
+   :hide:
+
+
+See the :doc:`guide` for additional information.
+
+Thread-safety notes
+-------------------
+
+In general, methods on `RequestHandler` and elsewhere in Tornado are
+not thread-safe. In particular, methods such as
+`~RequestHandler.write()`, `~RequestHandler.finish()`, and
+`~RequestHandler.flush()` must only be called from the main thread. If
+you use multiple threads it is important to use `.IOLoop.add_callback`
+to transfer control back to the main thread before finishing the
+request, or to limit your use of other threads to
+`.IOLoop.run_in_executor` and ensure that your callbacks running in
+the executor do not refer to Tornado objects.
+
+"""
+
+import base64
+import binascii
+import datetime
+import email.utils
+import functools
+import gzip
+import hashlib
+import hmac
+import http.cookies
+from inspect import isclass
+from io import BytesIO
+import mimetypes
+import numbers
+import os.path
+import re
+import socket
+import sys
+import threading
+import time
+import warnings
+import tornado
+import traceback
+import types
+import urllib.parse
+from urllib.parse import urlencode
+
+from tornado.concurrent import Future, future_set_result_unless_cancelled
+from tornado import escape
+from tornado import gen
+from tornado.httpserver import HTTPServer
+from tornado import httputil
+from tornado import iostream
+from tornado import locale
+from tornado.log import access_log, app_log, gen_log
+from tornado import template
+from tornado.escape import utf8, _unicode
+from tornado.routing import (
+    AnyMatches,
+    DefaultHostMatches,
+    HostMatches,
+    ReversibleRouter,
+    Rule,
+    ReversibleRuleRouter,
+    URLSpec,
+    _RuleList,
+)
+from tornado.util import ObjectDict, unicode_type, _websocket_mask
+
+url = URLSpec
+
+from typing import (
+    Dict,
+    Any,
+    Union,
+    Optional,
+    Awaitable,
+    Tuple,
+    List,
+    Callable,
+    Iterable,
+    Generator,
+    Type,
+    TypeVar,
+    cast,
+    overload,
+)
+from types import TracebackType
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Set  # noqa: F401
+
+
+# The following types are accepted by RequestHandler.set_header
+# and related methods.
+_HeaderTypes = Union[bytes, unicode_type, int, numbers.Integral, datetime.datetime]
+
+_CookieSecretTypes = Union[str, bytes, Dict[int, str], Dict[int, bytes]]
+
+
+MIN_SUPPORTED_SIGNED_VALUE_VERSION = 1
+"""The oldest signed value version supported by this version of Tornado.
+
+Signed values older than this version cannot be decoded.
+
+.. versionadded:: 3.2.1
+"""
+
+MAX_SUPPORTED_SIGNED_VALUE_VERSION = 2
+"""The newest signed value version supported by this version of Tornado.
+
+Signed values newer than this version cannot be decoded.
+
+.. versionadded:: 3.2.1
+"""
+
+DEFAULT_SIGNED_VALUE_VERSION = 2
+"""The signed value version produced by `.RequestHandler.create_signed_value`.
+
+May be overridden by passing a ``version`` keyword argument.
+
+.. versionadded:: 3.2.1
+"""
+
+DEFAULT_SIGNED_VALUE_MIN_VERSION = 1
+"""The oldest signed value accepted by `.RequestHandler.get_signed_cookie`.
+
+May be overridden by passing a ``min_version`` keyword argument.
+
+.. versionadded:: 3.2.1
+"""
+
+
+class _ArgDefaultMarker:
+    pass
+
+
+_ARG_DEFAULT = _ArgDefaultMarker()
+
+
+class RequestHandler(object):
+    """Base class for HTTP request handlers.
+
+    Subclasses must define at least one of the methods defined in the
+    "Entry points" section below.
+
+    Applications should not construct `RequestHandler` objects
+    directly and subclasses should not override ``__init__`` (override
+    `~RequestHandler.initialize` instead).
+
+    """
+
+    SUPPORTED_METHODS = ("GET", "HEAD", "POST", "DELETE", "PATCH", "PUT", "OPTIONS")
+
+    _template_loaders = {}  # type: Dict[str, template.BaseLoader]
+    _template_loader_lock = threading.Lock()
+    _remove_control_chars_regex = re.compile(r"[\x00-\x08\x0e-\x1f]")
+
+    _stream_request_body = False
+
+    # Will be set in _execute.
+    _transforms = None  # type: List[OutputTransform]
+    path_args = None  # type: List[str]
+    path_kwargs = None  # type: Dict[str, str]
+
+    def __init__(
+        self,
+        application: "Application",
+        request: httputil.HTTPServerRequest,
+        **kwargs: Any,
+    ) -> None:
+        super().__init__()
+
+        self.application = application
+        self.request = request
+        self._headers_written = False
+        self._finished = False
+        self._auto_finish = True
+        self._prepared_future = None
+        self.ui = ObjectDict(
+            (n, self._ui_method(m)) for n, m in application.ui_methods.items()
+        )
+        # UIModules are available as both `modules` and `_tt_modules` in the
+        # template namespace.  Historically only `modules` was available
+        # but could be clobbered by user additions to the namespace.
+        # The template {% module %} directive looks in `_tt_modules` to avoid
+        # possible conflicts.
+        self.ui["_tt_modules"] = _UIModuleNamespace(self, application.ui_modules)
+        self.ui["modules"] = self.ui["_tt_modules"]
+        self.clear()
+        assert self.request.connection is not None
+        # TODO: need to add set_close_callback to HTTPConnection interface
+        self.request.connection.set_close_callback(  # type: ignore
+            self.on_connection_close
+        )
+        self.initialize(**kwargs)  # type: ignore
+
+    def _initialize(self) -> None:
+        pass
+
+    initialize = _initialize  # type: Callable[..., None]
+    """Hook for subclass initialization. Called for each request.
+
+    A dictionary passed as the third argument of a ``URLSpec`` will be
+    supplied as keyword arguments to ``initialize()``.
+
+    Example::
+
+        class ProfileHandler(RequestHandler):
+            def initialize(self, database):
+                self.database = database
+
+            def get(self, username):
+                ...
+
+        app = Application([
+            (r'/user/(.*)', ProfileHandler, dict(database=database)),
+            ])
+    """
+
+    @property
+    def settings(self) -> Dict[str, Any]:
+        """An alias for `self.application.settings <Application.settings>`."""
+        return self.application.settings
+
+    def _unimplemented_method(self, *args: str, **kwargs: str) -> None:
+        raise HTTPError(405)
+
+    head = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    get = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    post = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    delete = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    patch = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    put = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+    options = _unimplemented_method  # type: Callable[..., Optional[Awaitable[None]]]
+
+    def prepare(self) -> Optional[Awaitable[None]]:
+        """Called at the beginning of a request before  `get`/`post`/etc.
+
+        Override this method to perform common initialization regardless
+        of the request method.
+
+        Asynchronous support: Use ``async def`` or decorate this method with
+        `.gen.coroutine` to make it asynchronous.
+        If this method returns an  ``Awaitable`` execution will not proceed
+        until the ``Awaitable`` is done.
+
+        .. versionadded:: 3.1
+           Asynchronous support.
+        """
+        pass
+
+    def on_finish(self) -> None:
+        """Called after the end of a request.
+
+        Override this method to perform cleanup, logging, etc.
+        This method is a counterpart to `prepare`.  ``on_finish`` may
+        not produce any output, as it is called after the response
+        has been sent to the client.
+        """
+        pass
+
+    def on_connection_close(self) -> None:
+        """Called in async handlers if the client closed the connection.
+
+        Override this to clean up resources associated with
+        long-lived connections.  Note that this method is called only if
+        the connection was closed during asynchronous processing; if you
+        need to do cleanup after every request override `on_finish`
+        instead.
+
+        Proxies may keep a connection open for a time (perhaps
+        indefinitely) after the client has gone away, so this method
+        may not be called promptly after the end user closes their
+        connection.
+        """
+        if _has_stream_request_body(self.__class__):
+            if not self.request._body_future.done():
+                self.request._body_future.set_exception(iostream.StreamClosedError())
+                self.request._body_future.exception()
+
+    def clear(self) -> None:
+        """Resets all headers and content for this response."""
+        self._headers = httputil.HTTPHeaders(
+            {
+                "Server": "TornadoServer/%s" % tornado.version,
+                "Content-Type": "text/html; charset=UTF-8",
+                "Date": httputil.format_timestamp(time.time()),
+            }
+        )
+        self.set_default_headers()
+        self._write_buffer = []  # type: List[bytes]
+        self._status_code = 200
+        self._reason = httputil.responses[200]
+
+    def set_default_headers(self) -> None:
+        """Override this to set HTTP headers at the beginning of the request.
+
+        For example, this is the place to set a custom ``Server`` header.
+        Note that setting such headers in the normal flow of request
+        processing may not do what you want, since headers may be reset
+        during error handling.
+        """
+        pass
+
+    def set_status(self, status_code: int, reason: Optional[str] = None) -> None:
+        """Sets the status code for our response.
+
+        :arg int status_code: Response status code.
+        :arg str reason: Human-readable reason phrase describing the status
+            code. If ``None``, it will be filled in from
+            `http.client.responses` or "Unknown".
+
+        .. versionchanged:: 5.0
+
+           No longer validates that the response code is in
+           `http.client.responses`.
+        """
+        self._status_code = status_code
+        if reason is not None:
+            self._reason = escape.native_str(reason)
+        else:
+            self._reason = httputil.responses.get(status_code, "Unknown")
+
+    def get_status(self) -> int:
+        """Returns the status code for our response."""
+        return self._status_code
+
+    def set_header(self, name: str, value: _HeaderTypes) -> None:
+        """Sets the given response header name and value.
+
+        All header values are converted to strings (`datetime` objects
+        are formatted according to the HTTP specification for the
+        ``Date`` header).
+
+        """
+        self._headers[name] = self._convert_header_value(value)
+
+    def add_header(self, name: str, value: _HeaderTypes) -> None:
+        """Adds the given response header and value.
+
+        Unlike `set_header`, `add_header` may be called multiple times
+        to return multiple values for the same header.
+        """
+        self._headers.add(name, self._convert_header_value(value))
+
+    def clear_header(self, name: str) -> None:
+        """Clears an outgoing header, undoing a previous `set_header` call.
+
+        Note that this method does not apply to multi-valued headers
+        set by `add_header`.
+        """
+        if name in self._headers:
+            del self._headers[name]
+
+    _INVALID_HEADER_CHAR_RE = re.compile(r"[\x00-\x1f]")
+
+    def _convert_header_value(self, value: _HeaderTypes) -> str:
+        # Convert the input value to a str. This type check is a bit
+        # subtle: The bytes case only executes on python 3, and the
+        # unicode case only executes on python 2, because the other
+        # cases are covered by the first match for str.
+        if isinstance(value, str):
+            retval = value
+        elif isinstance(value, bytes):
+            # Non-ascii characters in headers are not well supported,
+            # but if you pass bytes, use latin1 so they pass through as-is.
+            retval = value.decode("latin1")
+        elif isinstance(value, numbers.Integral):
+            # return immediately since we know the converted value will be safe
+            return str(value)
+        elif isinstance(value, datetime.datetime):
+            return httputil.format_timestamp(value)
+        else:
+            raise TypeError("Unsupported header value %r" % value)
+        # If \n is allowed into the header, it is possible to inject
+        # additional headers or split the request.
+        if RequestHandler._INVALID_HEADER_CHAR_RE.search(retval):
+            raise ValueError("Unsafe header value %r", retval)
+        return retval
+
+    @overload
+    def get_argument(self, name: str, default: str, strip: bool = True) -> str:
+        pass
+
+    @overload
+    def get_argument(  # noqa: F811
+        self, name: str, default: _ArgDefaultMarker = _ARG_DEFAULT, strip: bool = True
+    ) -> str:
+        pass
+
+    @overload
+    def get_argument(  # noqa: F811
+        self, name: str, default: None, strip: bool = True
+    ) -> Optional[str]:
+        pass
+
+    def get_argument(  # noqa: F811
+        self,
+        name: str,
+        default: Union[None, str, _ArgDefaultMarker] = _ARG_DEFAULT,
+        strip: bool = True,
+    ) -> Optional[str]:
+        """Returns the value of the argument with the given name.
+
+        If default is not provided, the argument is considered to be
+        required, and we raise a `MissingArgumentError` if it is missing.
+
+        If the argument appears in the request more than once, we return the
+        last value.
+
+        This method searches both the query and body arguments.
+        """
+        return self._get_argument(name, default, self.request.arguments, strip)
+
+    def get_arguments(self, name: str, strip: bool = True) -> List[str]:
+        """Returns a list of the arguments with the given name.
+
+        If the argument is not present, returns an empty list.
+
+        This method searches both the query and body arguments.
+        """
+
+        # Make sure `get_arguments` isn't accidentally being called with a
+        # positional argument that's assumed to be a default (like in
+        # `get_argument`.)
+        assert isinstance(strip, bool)
+
+        return self._get_arguments(name, self.request.arguments, strip)
+
+    def get_body_argument(
+        self,
+        name: str,
+        default: Union[None, str, _ArgDefaultMarker] = _ARG_DEFAULT,
+        strip: bool = True,
+    ) -> Optional[str]:
+        """Returns the value of the argument with the given name
+        from the request body.
+
+        If default is not provided, the argument is considered to be
+        required, and we raise a `MissingArgumentError` if it is missing.
+
+        If the argument appears in the url more than once, we return the
+        last value.
+
+        .. versionadded:: 3.2
+        """
+        return self._get_argument(name, default, self.request.body_arguments, strip)
+
+    def get_body_arguments(self, name: str, strip: bool = True) -> List[str]:
+        """Returns a list of the body arguments with the given name.
+
+        If the argument is not present, returns an empty list.
+
+        .. versionadded:: 3.2
+        """
+        return self._get_arguments(name, self.request.body_arguments, strip)
+
+    def get_query_argument(
+        self,
+        name: str,
+        default: Union[None, str, _ArgDefaultMarker] = _ARG_DEFAULT,
+        strip: bool = True,
+    ) -> Optional[str]:
+        """Returns the value of the argument with the given name
+        from the request query string.
+
+        If default is not provided, the argument is considered to be
+        required, and we raise a `MissingArgumentError` if it is missing.
+
+        If the argument appears in the url more than once, we return the
+        last value.
+
+        .. versionadded:: 3.2
+        """
+        return self._get_argument(name, default, self.request.query_arguments, strip)
+
+    def get_query_arguments(self, name: str, strip: bool = True) -> List[str]:
+        """Returns a list of the query arguments with the given name.
+
+        If the argument is not present, returns an empty list.
+
+        .. versionadded:: 3.2
+        """
+        return self._get_arguments(name, self.request.query_arguments, strip)
+
+    def _get_argument(
+        self,
+        name: str,
+        default: Union[None, str, _ArgDefaultMarker],
+        source: Dict[str, List[bytes]],
+        strip: bool = True,
+    ) -> Optional[str]:
+        args = self._get_arguments(name, source, strip=strip)
+        if not args:
+            if isinstance(default, _ArgDefaultMarker):
+                raise MissingArgumentError(name)
+            return default
+        return args[-1]
+
+    def _get_arguments(
+        self, name: str, source: Dict[str, List[bytes]], strip: bool = True
+    ) -> List[str]:
+        values = []
+        for v in source.get(name, []):
+            s = self.decode_argument(v, name=name)
+            if isinstance(s, unicode_type):
+                # Get rid of any weird control chars (unless decoding gave
+                # us bytes, in which case leave it alone)
+                s = RequestHandler._remove_control_chars_regex.sub(" ", s)
+            if strip:
+                s = s.strip()
+            values.append(s)
+        return values
+
+    def decode_argument(self, value: bytes, name: Optional[str] = None) -> str:
+        """Decodes an argument from the request.
+
+        The argument has been percent-decoded and is now a byte string.
+        By default, this method decodes the argument as utf-8 and returns
+        a unicode string, but this may be overridden in subclasses.
+
+        This method is used as a filter for both `get_argument()` and for
+        values extracted from the url and passed to `get()`/`post()`/etc.
+
+        The name of the argument is provided if known, but may be None
+        (e.g. for unnamed groups in the url regex).
+        """
+        try:
+            return _unicode(value)
+        except UnicodeDecodeError:
+            raise HTTPError(
+                400, "Invalid unicode in %s: %r" % (name or "url", value[:40])
+            )
+
+    @property
+    def cookies(self) -> Dict[str, http.cookies.Morsel]:
+        """An alias for
+        `self.request.cookies <.httputil.HTTPServerRequest.cookies>`."""
+        return self.request.cookies
+
+    def get_cookie(self, name: str, default: Optional[str] = None) -> Optional[str]:
+        """Returns the value of the request cookie with the given name.
+
+        If the named cookie is not present, returns ``default``.
+
+        This method only returns cookies that were present in the request.
+        It does not see the outgoing cookies set by `set_cookie` in this
+        handler.
+        """
+        if self.request.cookies is not None and name in self.request.cookies:
+            return self.request.cookies[name].value
+        return default
+
+    def set_cookie(
+        self,
+        name: str,
+        value: Union[str, bytes],
+        domain: Optional[str] = None,
+        expires: Optional[Union[float, Tuple, datetime.datetime]] = None,
+        path: str = "/",
+        expires_days: Optional[float] = None,
+        # Keyword-only args start here for historical reasons.
+        *,
+        max_age: Optional[int] = None,
+        httponly: bool = False,
+        secure: bool = False,
+        samesite: Optional[str] = None,
+        **kwargs: Any,
+    ) -> None:
+        """Sets an outgoing cookie name/value with the given options.
+
+        Newly-set cookies are not immediately visible via `get_cookie`;
+        they are not present until the next request.
+
+        Most arguments are passed directly to `http.cookies.Morsel` directly.
+        See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie
+        for more information.
+
+        ``expires`` may be a numeric timestamp as returned by `time.time`,
+        a time tuple as returned by `time.gmtime`, or a
+        `datetime.datetime` object. ``expires_days`` is provided as a convenience
+        to set an expiration time in days from today (if both are set, ``expires``
+        is used).
+
+        .. deprecated:: 6.3
+           Keyword arguments are currently accepted case-insensitively.
+           In Tornado 7.0 this will be changed to only accept lowercase
+           arguments.
+        """
+        # The cookie library only accepts type str, in both python 2 and 3
+        name = escape.native_str(name)
+        value = escape.native_str(value)
+        if re.search(r"[\x00-\x20]", name + value):
+            # Don't let us accidentally inject bad stuff
+            raise ValueError("Invalid cookie %r: %r" % (name, value))
+        if not hasattr(self, "_new_cookie"):
+            self._new_cookie = (
+                http.cookies.SimpleCookie()
+            )  # type: http.cookies.SimpleCookie
+        if name in self._new_cookie:
+            del self._new_cookie[name]
+        self._new_cookie[name] = value
+        morsel = self._new_cookie[name]
+        if domain:
+            morsel["domain"] = domain
+        if expires_days is not None and not expires:
+            expires = datetime.datetime.utcnow() + datetime.timedelta(days=expires_days)
+        if expires:
+            morsel["expires"] = httputil.format_timestamp(expires)
+        if path:
+            morsel["path"] = path
+        if max_age:
+            # Note change from _ to -.
+            morsel["max-age"] = str(max_age)
+        if httponly:
+            # Note that SimpleCookie ignores the value here. The presense of an
+            # httponly (or secure) key is treated as true.
+            morsel["httponly"] = True
+        if secure:
+            morsel["secure"] = True
+        if samesite:
+            morsel["samesite"] = samesite
+        if kwargs:
+            # The setitem interface is case-insensitive, so continue to support
+            # kwargs for backwards compatibility until we can remove deprecated
+            # features.
+            for k, v in kwargs.items():
+                morsel[k] = v
+            warnings.warn(
+                f"Deprecated arguments to set_cookie: {set(kwargs.keys())} "
+                "(should be lowercase)",
+                DeprecationWarning,
+            )
+
+    def clear_cookie(self, name: str, **kwargs: Any) -> None:
+        """Deletes the cookie with the given name.
+
+        This method accepts the same arguments as `set_cookie`, except for
+        ``expires`` and ``max_age``. Clearing a cookie requires the same
+        ``domain`` and ``path`` arguments as when it was set. In some cases the
+        ``samesite`` and ``secure`` arguments are also required to match. Other
+        arguments are ignored.
+
+        Similar to `set_cookie`, the effect of this method will not be
+        seen until the following request.
+
+        .. versionchanged:: 6.3
+
+           Now accepts all keyword arguments that ``set_cookie`` does.
+           The ``samesite`` and ``secure`` flags have recently become
+           required for clearing ``samesite="none"`` cookies.
+        """
+        for excluded_arg in ["expires", "max_age"]:
+            if excluded_arg in kwargs:
+                raise TypeError(
+                    f"clear_cookie() got an unexpected keyword argument '{excluded_arg}'"
+                )
+        expires = datetime.datetime.utcnow() - datetime.timedelta(days=365)
+        self.set_cookie(name, value="", expires=expires, **kwargs)
+
+    def clear_all_cookies(self, **kwargs: Any) -> None:
+        """Attempt to delete all the cookies the user sent with this request.
+
+        See `clear_cookie` for more information on keyword arguments. Due to
+        limitations of the cookie protocol, it is impossible to determine on the
+        server side which values are necessary for the ``domain``, ``path``,
+        ``samesite``, or ``secure`` arguments, this method can only be
+        successful if you consistently use the same values for these arguments
+        when setting cookies.
+
+        Similar to `set_cookie`, the effect of this method will not be seen
+        until the following request.
+
+        .. versionchanged:: 3.2
+
+           Added the ``path`` and ``domain`` parameters.
+
+        .. versionchanged:: 6.3
+
+           Now accepts all keyword arguments that ``set_cookie`` does.
+
+        .. deprecated:: 6.3
+
+           The increasingly complex rules governing cookies have made it
+           impossible for a ``clear_all_cookies`` method to work reliably
+           since all we know about cookies are their names. Applications
+           should generally use ``clear_cookie`` one at a time instead.
+        """
+        for name in self.request.cookies:
+            self.clear_cookie(name, **kwargs)
+
+    def set_signed_cookie(
+        self,
+        name: str,
+        value: Union[str, bytes],
+        expires_days: Optional[float] = 30,
+        version: Optional[int] = None,
+        **kwargs: Any,
+    ) -> None:
+        """Signs and timestamps a cookie so it cannot be forged.
+
+        You must specify the ``cookie_secret`` setting in your Application
+        to use this method. It should be a long, random sequence of bytes
+        to be used as the HMAC secret for the signature.
+
+        To read a cookie set with this method, use `get_signed_cookie()`.
+
+        Note that the ``expires_days`` parameter sets the lifetime of the
+        cookie in the browser, but is independent of the ``max_age_days``
+        parameter to `get_signed_cookie`.
+        A value of None limits the lifetime to the current browser session.
+
+        Secure cookies may contain arbitrary byte values, not just unicode
+        strings (unlike regular cookies)
+
+        Similar to `set_cookie`, the effect of this method will not be
+        seen until the following request.
+
+        .. versionchanged:: 3.2.1
+
+           Added the ``version`` argument.  Introduced cookie version 2
+           and made it the default.
+
+        .. versionchanged:: 6.3
+
+           Renamed from ``set_secure_cookie`` to ``set_signed_cookie`` to
+           avoid confusion with other uses of "secure" in cookie attributes
+           and prefixes. The old name remains as an alias.
+        """
+        self.set_cookie(
+            name,
+            self.create_signed_value(name, value, version=version),
+            expires_days=expires_days,
+            **kwargs,
+        )
+
+    set_secure_cookie = set_signed_cookie
+
+    def create_signed_value(
+        self, name: str, value: Union[str, bytes], version: Optional[int] = None
+    ) -> bytes:
+        """Signs and timestamps a string so it cannot be forged.
+
+        Normally used via set_signed_cookie, but provided as a separate
+        method for non-cookie uses.  To decode a value not stored
+        as a cookie use the optional value argument to get_signed_cookie.
+
+        .. versionchanged:: 3.2.1
+
+           Added the ``version`` argument.  Introduced cookie version 2
+           and made it the default.
+        """
+        self.require_setting("cookie_secret", "secure cookies")
+        secret = self.application.settings["cookie_secret"]
+        key_version = None
+        if isinstance(secret, dict):
+            if self.application.settings.get("key_version") is None:
+                raise Exception("key_version setting must be used for secret_key dicts")
+            key_version = self.application.settings["key_version"]
+
+        return create_signed_value(
+            secret, name, value, version=version, key_version=key_version
+        )
+
+    def get_signed_cookie(
+        self,
+        name: str,
+        value: Optional[str] = None,
+        max_age_days: float = 31,
+        min_version: Optional[int] = None,
+    ) -> Optional[bytes]:
+        """Returns the given signed cookie if it validates, or None.
+
+        The decoded cookie value is returned as a byte string (unlike
+        `get_cookie`).
+
+        Similar to `get_cookie`, this method only returns cookies that
+        were present in the request. It does not see outgoing cookies set by
+        `set_signed_cookie` in this handler.
+
+        .. versionchanged:: 3.2.1
+
+           Added the ``min_version`` argument.  Introduced cookie version 2;
+           both versions 1 and 2 are accepted by default.
+
+         .. versionchanged:: 6.3
+
+           Renamed from ``get_secure_cookie`` to ``get_signed_cookie`` to
+           avoid confusion with other uses of "secure" in cookie attributes
+           and prefixes. The old name remains as an alias.
+
+        """
+        self.require_setting("cookie_secret", "secure cookies")
+        if value is None:
+            value = self.get_cookie(name)
+        return decode_signed_value(
+            self.application.settings["cookie_secret"],
+            name,
+            value,
+            max_age_days=max_age_days,
+            min_version=min_version,
+        )
+
+    get_secure_cookie = get_signed_cookie
+
+    def get_signed_cookie_key_version(
+        self, name: str, value: Optional[str] = None
+    ) -> Optional[int]:
+        """Returns the signing key version of the secure cookie.
+
+        The version is returned as int.
+
+        .. versionchanged:: 6.3
+
+           Renamed from ``get_secure_cookie_key_version`` to
+           ``set_signed_cookie_key_version`` to avoid confusion with other
+           uses of "secure" in cookie attributes and prefixes. The old name
+           remains as an alias.
+
+        """
+        self.require_setting("cookie_secret", "secure cookies")
+        if value is None:
+            value = self.get_cookie(name)
+        if value is None:
+            return None
+        return get_signature_key_version(value)
+
+    get_secure_cookie_key_version = get_signed_cookie_key_version
+
+    def redirect(
+        self, url: str, permanent: bool = False, status: Optional[int] = None
+    ) -> None:
+        """Sends a redirect to the given (optionally relative) URL.
+
+        If the ``status`` argument is specified, that value is used as the
+        HTTP status code; otherwise either 301 (permanent) or 302
+        (temporary) is chosen based on the ``permanent`` argument.
+        The default is 302 (temporary).
+        """
+        if self._headers_written:
+            raise Exception("Cannot redirect after headers have been written")
+        if status is None:
+            status = 301 if permanent else 302
+        else:
+            assert isinstance(status, int) and 300 <= status <= 399
+        self.set_status(status)
+        self.set_header("Location", utf8(url))
+        self.finish()
+
+    def write(self, chunk: Union[str, bytes, dict]) -> None:
+        """Writes the given chunk to the output buffer.
+
+        To write the output to the network, use the `flush()` method below.
+
+        If the given chunk is a dictionary, we write it as JSON and set
+        the Content-Type of the response to be ``application/json``.
+        (if you want to send JSON as a different ``Content-Type``, call
+        ``set_header`` *after* calling ``write()``).
+
+        Note that lists are not converted to JSON because of a potential
+        cross-site security vulnerability.  All JSON output should be
+        wrapped in a dictionary.  More details at
+        http://haacked.com/archive/2009/06/25/json-hijacking.aspx/ and
+        https://github.com/facebook/tornado/issues/1009
+        """
+        if self._finished:
+            raise RuntimeError("Cannot write() after finish()")
+        if not isinstance(chunk, (bytes, unicode_type, dict)):
+            message = "write() only accepts bytes, unicode, and dict objects"
+            if isinstance(chunk, list):
+                message += (
+                    ". Lists not accepted for security reasons; see "
+                    + "http://www.tornadoweb.org/en/stable/web.html#tornado.web.RequestHandler.write"  # noqa: E501
+                )
+            raise TypeError(message)
+        if isinstance(chunk, dict):
+            chunk = escape.json_encode(chunk)
+            self.set_header("Content-Type", "application/json; charset=UTF-8")
+        chunk = utf8(chunk)
+        self._write_buffer.append(chunk)
+
+    def render(self, template_name: str, **kwargs: Any) -> "Future[None]":
+        """Renders the template with the given arguments as the response.
+
+        ``render()`` calls ``finish()``, so no other output methods can be called
+        after it.
+
+        Returns a `.Future` with the same semantics as the one returned by `finish`.
+        Awaiting this `.Future` is optional.
+
+        .. versionchanged:: 5.1
+
+           Now returns a `.Future` instead of ``None``.
+        """
+        if self._finished:
+            raise RuntimeError("Cannot render() after finish()")
+        html = self.render_string(template_name, **kwargs)
+
+        # Insert the additional JS and CSS added by the modules on the page
+        js_embed = []
+        js_files = []
+        css_embed = []
+        css_files = []
+        html_heads = []
+        html_bodies = []
+        for module in getattr(self, "_active_modules", {}).values():
+            embed_part = module.embedded_javascript()
+            if embed_part:
+                js_embed.append(utf8(embed_part))
+            file_part = module.javascript_files()
+            if file_part:
+                if isinstance(file_part, (unicode_type, bytes)):
+                    js_files.append(_unicode(file_part))
+                else:
+                    js_files.extend(file_part)
+            embed_part = module.embedded_css()
+            if embed_part:
+                css_embed.append(utf8(embed_part))
+            file_part = module.css_files()
+            if file_part:
+                if isinstance(file_part, (unicode_type, bytes)):
+                    css_files.append(_unicode(file_part))
+                else:
+                    css_files.extend(file_part)
+            head_part = module.html_head()
+            if head_part:
+                html_heads.append(utf8(head_part))
+            body_part = module.html_body()
+            if body_part:
+                html_bodies.append(utf8(body_part))
+
+        if js_files:
+            # Maintain order of JavaScript files given by modules
+            js = self.render_linked_js(js_files)
+            sloc = html.rindex(b"</body>")
+            html = html[:sloc] + utf8(js) + b"\n" + html[sloc:]
+        if js_embed:
+            js_bytes = self.render_embed_js(js_embed)
+            sloc = html.rindex(b"</body>")
+            html = html[:sloc] + js_bytes + b"\n" + html[sloc:]
+        if css_files:
+            css = self.render_linked_css(css_files)
+            hloc = html.index(b"</head>")
+            html = html[:hloc] + utf8(css) + b"\n" + html[hloc:]
+        if css_embed:
+            css_bytes = self.render_embed_css(css_embed)
+            hloc = html.index(b"</head>")
+            html = html[:hloc] + css_bytes + b"\n" + html[hloc:]
+        if html_heads:
+            hloc = html.index(b"</head>")
+            html = html[:hloc] + b"".join(html_heads) + b"\n" + html[hloc:]
+        if html_bodies:
+            hloc = html.index(b"</body>")
+            html = html[:hloc] + b"".join(html_bodies) + b"\n" + html[hloc:]
+        return self.finish(html)
+
+    def render_linked_js(self, js_files: Iterable[str]) -> str:
+        """Default method used to render the final js links for the
+        rendered webpage.
+
+        Override this method in a sub-classed controller to change the output.
+        """
+        paths = []
+        unique_paths = set()  # type: Set[str]
+
+        for path in js_files:
+            if not is_absolute(path):
+                path = self.static_url(path)
+            if path not in unique_paths:
+                paths.append(path)
+                unique_paths.add(path)
+
+        return "".join(
+            '<script src="'
+            + escape.xhtml_escape(p)
+            + '" type="text/javascript"></script>'
+            for p in paths
+        )
+
+    def render_embed_js(self, js_embed: Iterable[bytes]) -> bytes:
+        """Default method used to render the final embedded js for the
+        rendered webpage.
+
+        Override this method in a sub-classed controller to change the output.
+        """
+        return (
+            b'<script type="text/javascript">\n//<![CDATA[\n'
+            + b"\n".join(js_embed)
+            + b"\n//]]>\n</script>"
+        )
+
+    def render_linked_css(self, css_files: Iterable[str]) -> str:
+        """Default method used to render the final css links for the
+        rendered webpage.
+
+        Override this method in a sub-classed controller to change the output.
+        """
+        paths = []
+        unique_paths = set()  # type: Set[str]
+
+        for path in css_files:
+            if not is_absolute(path):
+                path = self.static_url(path)
+            if path not in unique_paths:
+                paths.append(path)
+                unique_paths.add(path)
+
+        return "".join(
+            '<link href="' + escape.xhtml_escape(p) + '" '
+            'type="text/css" rel="stylesheet"/>'
+            for p in paths
+        )
+
+    def render_embed_css(self, css_embed: Iterable[bytes]) -> bytes:
+        """Default method used to render the final embedded css for the
+        rendered webpage.
+
+        Override this method in a sub-classed controller to change the output.
+        """
+        return b'<style type="text/css">\n' + b"\n".join(css_embed) + b"\n</style>"
+
+    def render_string(self, template_name: str, **kwargs: Any) -> bytes:
+        """Generate the given template with the given arguments.
+
+        We return the generated byte string (in utf8). To generate and
+        write a template as a response, use render() above.
+        """
+        # If no template_path is specified, use the path of the calling file
+        template_path = self.get_template_path()
+        if not template_path:
+            frame = sys._getframe(0)
+            web_file = frame.f_code.co_filename
+            while frame.f_code.co_filename == web_file and frame.f_back is not None:
+                frame = frame.f_back
+            assert frame.f_code.co_filename is not None
+            template_path = os.path.dirname(frame.f_code.co_filename)
+        with RequestHandler._template_loader_lock:
+            if template_path not in RequestHandler._template_loaders:
+                loader = self.create_template_loader(template_path)
+                RequestHandler._template_loaders[template_path] = loader
+            else:
+                loader = RequestHandler._template_loaders[template_path]
+        t = loader.load(template_name)
+        namespace = self.get_template_namespace()
+        namespace.update(kwargs)
+        return t.generate(**namespace)
+
+    def get_template_namespace(self) -> Dict[str, Any]:
+        """Returns a dictionary to be used as the default template namespace.
+
+        May be overridden by subclasses to add or modify values.
+
+        The results of this method will be combined with additional
+        defaults in the `tornado.template` module and keyword arguments
+        to `render` or `render_string`.
+        """
+        namespace = dict(
+            handler=self,
+            request=self.request,
+            current_user=self.current_user,
+            locale=self.locale,
+            _=self.locale.translate,
+            pgettext=self.locale.pgettext,
+            static_url=self.static_url,
+            xsrf_form_html=self.xsrf_form_html,
+            reverse_url=self.reverse_url,
+        )
+        namespace.update(self.ui)
+        return namespace
+
+    def create_template_loader(self, template_path: str) -> template.BaseLoader:
+        """Returns a new template loader for the given path.
+
+        May be overridden by subclasses.  By default returns a
+        directory-based loader on the given path, using the
+        ``autoescape`` and ``template_whitespace`` application
+        settings.  If a ``template_loader`` application setting is
+        supplied, uses that instead.
+        """
+        settings = self.application.settings
+        if "template_loader" in settings:
+            return settings["template_loader"]
+        kwargs = {}
+        if "autoescape" in settings:
+            # autoescape=None means "no escaping", so we have to be sure
+            # to only pass this kwarg if the user asked for it.
+            kwargs["autoescape"] = settings["autoescape"]
+        if "template_whitespace" in settings:
+            kwargs["whitespace"] = settings["template_whitespace"]
+        return template.Loader(template_path, **kwargs)
+
+    def flush(self, include_footers: bool = False) -> "Future[None]":
+        """Flushes the current output buffer to the network.
+
+        .. versionchanged:: 4.0
+           Now returns a `.Future` if no callback is given.
+
+        .. versionchanged:: 6.0
+
+           The ``callback`` argument was removed.
+        """
+        assert self.request.connection is not None
+        chunk = b"".join(self._write_buffer)
+        self._write_buffer = []
+        if not self._headers_written:
+            self._headers_written = True
+            for transform in self._transforms:
+                assert chunk is not None
+                (
+                    self._status_code,
+                    self._headers,
+                    chunk,
+                ) = transform.transform_first_chunk(
+                    self._status_code, self._headers, chunk, include_footers
+                )
+            # Ignore the chunk and only write the headers for HEAD requests
+            if self.request.method == "HEAD":
+                chunk = b""
+
+            # Finalize the cookie headers (which have been stored in a side
+            # object so an outgoing cookie could be overwritten before it
+            # is sent).
+            if hasattr(self, "_new_cookie"):
+                for cookie in self._new_cookie.values():
+                    self.add_header("Set-Cookie", cookie.OutputString(None))
+
+            start_line = httputil.ResponseStartLine("", self._status_code, self._reason)
+            return self.request.connection.write_headers(
+                start_line, self._headers, chunk
+            )
+        else:
+            for transform in self._transforms:
+                chunk = transform.transform_chunk(chunk, include_footers)
+            # Ignore the chunk and only write the headers for HEAD requests
+            if self.request.method != "HEAD":
+                return self.request.connection.write(chunk)
+            else:
+                future = Future()  # type: Future[None]
+                future.set_result(None)
+                return future
+
+    def finish(self, chunk: Optional[Union[str, bytes, dict]] = None) -> "Future[None]":
+        """Finishes this response, ending the HTTP request.
+
+        Passing a ``chunk`` to ``finish()`` is equivalent to passing that
+        chunk to ``write()`` and then calling ``finish()`` with no arguments.
+
+        Returns a `.Future` which may optionally be awaited to track the sending
+        of the response to the client. This `.Future` resolves when all the response
+        data has been sent, and raises an error if the connection is closed before all
+        data can be sent.
+
+        .. versionchanged:: 5.1
+
+           Now returns a `.Future` instead of ``None``.
+        """
+        if self._finished:
+            raise RuntimeError("finish() called twice")
+
+        if chunk is not None:
+            self.write(chunk)
+
+        # Automatically support ETags and add the Content-Length header if
+        # we have not flushed any content yet.
+        if not self._headers_written:
+            if (
+                self._status_code == 200
+                and self.request.method in ("GET", "HEAD")
+                and "Etag" not in self._headers
+            ):
+                self.set_etag_header()
+                if self.check_etag_header():
+                    self._write_buffer = []
+                    self.set_status(304)
+            if self._status_code in (204, 304) or (100 <= self._status_code < 200):
+                assert not self._write_buffer, (
+                    "Cannot send body with %s" % self._status_code
+                )
+                self._clear_representation_headers()
+            elif "Content-Length" not in self._headers:
+                content_length = sum(len(part) for part in self._write_buffer)
+                self.set_header("Content-Length", content_length)
+
+        assert self.request.connection is not None
+        # Now that the request is finished, clear the callback we
+        # set on the HTTPConnection (which would otherwise prevent the
+        # garbage collection of the RequestHandler when there
+        # are keepalive connections)
+        self.request.connection.set_close_callback(None)  # type: ignore
+
+        future = self.flush(include_footers=True)
+        self.request.connection.finish()
+        self._log()
+        self._finished = True
+        self.on_finish()
+        self._break_cycles()
+        return future
+
+    def detach(self) -> iostream.IOStream:
+        """Take control of the underlying stream.
+
+        Returns the underlying `.IOStream` object and stops all
+        further HTTP processing. Intended for implementing protocols
+        like websockets that tunnel over an HTTP handshake.
+
+        This method is only supported when HTTP/1.1 is used.
+
+        .. versionadded:: 5.1
+        """
+        self._finished = True
+        # TODO: add detach to HTTPConnection?
+        return self.request.connection.detach()  # type: ignore
+
+    def _break_cycles(self) -> None:
+        # Break up a reference cycle between this handler and the
+        # _ui_module closures to allow for faster GC on CPython.
+        self.ui = None  # type: ignore
+
+    def send_error(self, status_code: int = 500, **kwargs: Any) -> None:
+        """Sends the given HTTP error code to the browser.
+
+        If `flush()` has already been called, it is not possible to send
+        an error, so this method will simply terminate the response.
+        If output has been written but not yet flushed, it will be discarded
+        and replaced with the error page.
+
+        Override `write_error()` to customize the error page that is returned.
+        Additional keyword arguments are passed through to `write_error`.
+        """
+        if self._headers_written:
+            gen_log.error("Cannot send error response after headers written")
+            if not self._finished:
+                # If we get an error between writing headers and finishing,
+                # we are unlikely to be able to finish due to a
+                # Content-Length mismatch. Try anyway to release the
+                # socket.
+                try:
+                    self.finish()
+                except Exception:
+                    gen_log.error("Failed to flush partial response", exc_info=True)
+            return
+        self.clear()
+
+        reason = kwargs.get("reason")
+        if "exc_info" in kwargs:
+            exception = kwargs["exc_info"][1]
+            if isinstance(exception, HTTPError) and exception.reason:
+                reason = exception.reason
+        self.set_status(status_code, reason=reason)
+        try:
+            self.write_error(status_code, **kwargs)
+        except Exception:
+            app_log.error("Uncaught exception in write_error", exc_info=True)
+        if not self._finished:
+            self.finish()
+
+    def write_error(self, status_code: int, **kwargs: Any) -> None:
+        """Override to implement custom error pages.
+
+        ``write_error`` may call `write`, `render`, `set_header`, etc
+        to produce output as usual.
+
+        If this error was caused by an uncaught exception (including
+        HTTPError), an ``exc_info`` triple will be available as
+        ``kwargs["exc_info"]``.  Note that this exception may not be
+        the "current" exception for purposes of methods like
+        ``sys.exc_info()`` or ``traceback.format_exc``.
+        """
+        if self.settings.get("serve_traceback") and "exc_info" in kwargs:
+            # in debug mode, try to send a traceback
+            self.set_header("Content-Type", "text/plain")
+            for line in traceback.format_exception(*kwargs["exc_info"]):
+                self.write(line)
+            self.finish()
+        else:
+            self.finish(
+                "<html><title>%(code)d: %(message)s</title>"
+                "<body>%(code)d: %(message)s</body></html>"
+                % {"code": status_code, "message": self._reason}
+            )
+
+    @property
+    def locale(self) -> tornado.locale.Locale:
+        """The locale for the current session.
+
+        Determined by either `get_user_locale`, which you can override to
+        set the locale based on, e.g., a user preference stored in a
+        database, or `get_browser_locale`, which uses the ``Accept-Language``
+        header.
+
+        .. versionchanged: 4.1
+           Added a property setter.
+        """
+        if not hasattr(self, "_locale"):
+            loc = self.get_user_locale()
+            if loc is not None:
+                self._locale = loc
+            else:
+                self._locale = self.get_browser_locale()
+                assert self._locale
+        return self._locale
+
+    @locale.setter
+    def locale(self, value: tornado.locale.Locale) -> None:
+        self._locale = value
+
+    def get_user_locale(self) -> Optional[tornado.locale.Locale]:
+        """Override to determine the locale from the authenticated user.
+
+        If None is returned, we fall back to `get_browser_locale()`.
+
+        This method should return a `tornado.locale.Locale` object,
+        most likely obtained via a call like ``tornado.locale.get("en")``
+        """
+        return None
+
+    def get_browser_locale(self, default: str = "en_US") -> tornado.locale.Locale:
+        """Determines the user's locale from ``Accept-Language`` header.
+
+        See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
+        """
+        if "Accept-Language" in self.request.headers:
+            languages = self.request.headers["Accept-Language"].split(",")
+            locales = []
+            for language in languages:
+                parts = language.strip().split(";")
+                if len(parts) > 1 and parts[1].strip().startswith("q="):
+                    try:
+                        score = float(parts[1].strip()[2:])
+                        if score < 0:
+                            raise ValueError()
+                    except (ValueError, TypeError):
+                        score = 0.0
+                else:
+                    score = 1.0
+                if score > 0:
+                    locales.append((parts[0], score))
+            if locales:
+                locales.sort(key=lambda pair: pair[1], reverse=True)
+                codes = [loc[0] for loc in locales]
+                return locale.get(*codes)
+        return locale.get(default)
+
+    @property
+    def current_user(self) -> Any:
+        """The authenticated user for this request.
+
+        This is set in one of two ways:
+
+        * A subclass may override `get_current_user()`, which will be called
+          automatically the first time ``self.current_user`` is accessed.
+          `get_current_user()` will only be called once per request,
+          and is cached for future access::
+
+              def get_current_user(self):
+                  user_cookie = self.get_signed_cookie("user")
+                  if user_cookie:
+                      return json.loads(user_cookie)
+                  return None
+
+        * It may be set as a normal variable, typically from an overridden
+          `prepare()`::
+
+              @gen.coroutine
+              def prepare(self):
+                  user_id_cookie = self.get_signed_cookie("user_id")
+                  if user_id_cookie:
+                      self.current_user = yield load_user(user_id_cookie)
+
+        Note that `prepare()` may be a coroutine while `get_current_user()`
+        may not, so the latter form is necessary if loading the user requires
+        asynchronous operations.
+
+        The user object may be any type of the application's choosing.
+        """
+        if not hasattr(self, "_current_user"):
+            self._current_user = self.get_current_user()
+        return self._current_user
+
+    @current_user.setter
+    def current_user(self, value: Any) -> None:
+        self._current_user = value
+
+    def get_current_user(self) -> Any:
+        """Override to determine the current user from, e.g., a cookie.
+
+        This method may not be a coroutine.
+        """
+        return None
+
+    def get_login_url(self) -> str:
+        """Override to customize the login URL based on the request.
+
+        By default, we use the ``login_url`` application setting.
+        """
+        self.require_setting("login_url", "@tornado.web.authenticated")
+        return self.application.settings["login_url"]
+
+    def get_template_path(self) -> Optional[str]:
+        """Override to customize template path for each handler.
+
+        By default, we use the ``template_path`` application setting.
+        Return None to load templates relative to the calling file.
+        """
+        return self.application.settings.get("template_path")
+
+    @property
+    def xsrf_token(self) -> bytes:
+        """The XSRF-prevention token for the current user/session.
+
+        To prevent cross-site request forgery, we set an '_xsrf' cookie
+        and include the same '_xsrf' value as an argument with all POST
+        requests. If the two do not match, we reject the form submission
+        as a potential forgery.
+
+        See http://en.wikipedia.org/wiki/Cross-site_request_forgery
+
+        This property is of type `bytes`, but it contains only ASCII
+        characters. If a character string is required, there is no
+        need to base64-encode it; just decode the byte string as
+        UTF-8.
+
+        .. versionchanged:: 3.2.2
+           The xsrf token will now be have a random mask applied in every
+           request, which makes it safe to include the token in pages
+           that are compressed.  See http://breachattack.com for more
+           information on the issue fixed by this change.  Old (version 1)
+           cookies will be converted to version 2 when this method is called
+           unless the ``xsrf_cookie_version`` `Application` setting is
+           set to 1.
+
+        .. versionchanged:: 4.3
+           The ``xsrf_cookie_kwargs`` `Application` setting may be
+           used to supply additional cookie options (which will be
+           passed directly to `set_cookie`). For example,
+           ``xsrf_cookie_kwargs=dict(httponly=True, secure=True)``
+           will set the ``secure`` and ``httponly`` flags on the
+           ``_xsrf`` cookie.
+        """
+        if not hasattr(self, "_xsrf_token"):
+            version, token, timestamp = self._get_raw_xsrf_token()
+            output_version = self.settings.get("xsrf_cookie_version", 2)
+            cookie_kwargs = self.settings.get("xsrf_cookie_kwargs", {})
+            if output_version == 1:
+                self._xsrf_token = binascii.b2a_hex(token)
+            elif output_version == 2:
+                mask = os.urandom(4)
+                self._xsrf_token = b"|".join(
+                    [
+                        b"2",
+                        binascii.b2a_hex(mask),
+                        binascii.b2a_hex(_websocket_mask(mask, token)),
+                        utf8(str(int(timestamp))),
+                    ]
+                )
+            else:
+                raise ValueError("unknown xsrf cookie version %d", output_version)
+            if version is None:
+                if self.current_user and "expires_days" not in cookie_kwargs:
+                    cookie_kwargs["expires_days"] = 30
+                cookie_name = self.settings.get("xsrf_cookie_name", "_xsrf")
+                self.set_cookie(cookie_name, self._xsrf_token, **cookie_kwargs)
+        return self._xsrf_token
+
+    def _get_raw_xsrf_token(self) -> Tuple[Optional[int], bytes, float]:
+        """Read or generate the xsrf token in its raw form.
+
+        The raw_xsrf_token is a tuple containing:
+
+        * version: the version of the cookie from which this token was read,
+          or None if we generated a new token in this request.
+        * token: the raw token data; random (non-ascii) bytes.
+        * timestamp: the time this token was generated (will not be accurate
+          for version 1 cookies)
+        """
+        if not hasattr(self, "_raw_xsrf_token"):
+            cookie_name = self.settings.get("xsrf_cookie_name", "_xsrf")
+            cookie = self.get_cookie(cookie_name)
+            if cookie:
+                version, token, timestamp = self._decode_xsrf_token(cookie)
+            else:
+                version, token, timestamp = None, None, None
+            if token is None:
+                version = None
+                token = os.urandom(16)
+                timestamp = time.time()
+            assert token is not None
+            assert timestamp is not None
+            self._raw_xsrf_token = (version, token, timestamp)
+        return self._raw_xsrf_token
+
+    def _decode_xsrf_token(
+        self, cookie: str
+    ) -> Tuple[Optional[int], Optional[bytes], Optional[float]]:
+        """Convert a cookie string into a the tuple form returned by
+        _get_raw_xsrf_token.
+        """
+
+        try:
+            m = _signed_value_version_re.match(utf8(cookie))
+
+            if m:
+                version = int(m.group(1))
+                if version == 2:
+                    _, mask_str, masked_token, timestamp_str = cookie.split("|")
+
+                    mask = binascii.a2b_hex(utf8(mask_str))
+                    token = _websocket_mask(mask, binascii.a2b_hex(utf8(masked_token)))
+                    timestamp = int(timestamp_str)
+                    return version, token, timestamp
+                else:
+                    # Treat unknown versions as not present instead of failing.
+                    raise Exception("Unknown xsrf cookie version")
+            else:
+                version = 1
+                try:
+                    token = binascii.a2b_hex(utf8(cookie))
+                except (binascii.Error, TypeError):
+                    token = utf8(cookie)
+                # We don't have a usable timestamp in older versions.
+                timestamp = int(time.time())
+                return (version, token, timestamp)
+        except Exception:
+            # Catch exceptions and return nothing instead of failing.
+            gen_log.debug("Uncaught exception in _decode_xsrf_token", exc_info=True)
+            return None, None, None
+
+    def check_xsrf_cookie(self) -> None:
+        """Verifies that the ``_xsrf`` cookie matches the ``_xsrf`` argument.
+
+        To prevent cross-site request forgery, we set an ``_xsrf``
+        cookie and include the same value as a non-cookie
+        field with all ``POST`` requests. If the two do not match, we
+        reject the form submission as a potential forgery.
+
+        The ``_xsrf`` value may be set as either a form field named ``_xsrf``
+        or in a custom HTTP header named ``X-XSRFToken`` or ``X-CSRFToken``
+        (the latter is accepted for compatibility with Django).
+
+        See http://en.wikipedia.org/wiki/Cross-site_request_forgery
+
+        .. versionchanged:: 3.2.2
+           Added support for cookie version 2.  Both versions 1 and 2 are
+           supported.
+        """
+        # Prior to release 1.1.1, this check was ignored if the HTTP header
+        # ``X-Requested-With: XMLHTTPRequest`` was present.  This exception
+        # has been shown to be insecure and has been removed.  For more
+        # information please see
+        # http://www.djangoproject.com/weblog/2011/feb/08/security/
+        # http://weblog.rubyonrails.org/2011/2/8/csrf-protection-bypass-in-ruby-on-rails
+        token = (
+            self.get_argument("_xsrf", None)
+            or self.request.headers.get("X-Xsrftoken")
+            or self.request.headers.get("X-Csrftoken")
+        )
+        if not token:
+            raise HTTPError(403, "'_xsrf' argument missing from POST")
+        _, token, _ = self._decode_xsrf_token(token)
+        _, expected_token, _ = self._get_raw_xsrf_token()
+        if not token:
+            raise HTTPError(403, "'_xsrf' argument has invalid format")
+        if not hmac.compare_digest(utf8(token), utf8(expected_token)):
+            raise HTTPError(403, "XSRF cookie does not match POST argument")
+
+    def xsrf_form_html(self) -> str:
+        """An HTML ``<input/>`` element to be included with all POST forms.
+
+        It defines the ``_xsrf`` input value, which we check on all POST
+        requests to prevent cross-site request forgery. If you have set
+        the ``xsrf_cookies`` application setting, you must include this
+        HTML within all of your HTML forms.
+
+        In a template, this method should be called with ``{% module
+        xsrf_form_html() %}``
+
+        See `check_xsrf_cookie()` above for more information.
+        """
+        return (
+            '<input type="hidden" name="_xsrf" value="'
+            + escape.xhtml_escape(self.xsrf_token)
+            + '"/>'
+        )
+
+    def static_url(
+        self, path: str, include_host: Optional[bool] = None, **kwargs: Any
+    ) -> str:
+        """Returns a static URL for the given relative static file path.
+
+        This method requires you set the ``static_path`` setting in your
+        application (which specifies the root directory of your static
+        files).
+
+        This method returns a versioned url (by default appending
+        ``?v=<signature>``), which allows the static files to be
+        cached indefinitely.  This can be disabled by passing
+        ``include_version=False`` (in the default implementation;
+        other static file implementations are not required to support
+        this, but they may support other options).
+
+        By default this method returns URLs relative to the current
+        host, but if ``include_host`` is true the URL returned will be
+        absolute.  If this handler has an ``include_host`` attribute,
+        that value will be used as the default for all `static_url`
+        calls that do not pass ``include_host`` as a keyword argument.
+
+        """
+        self.require_setting("static_path", "static_url")
+        get_url = self.settings.get(
+            "static_handler_class", StaticFileHandler
+        ).make_static_url
+
+        if include_host is None:
+            include_host = getattr(self, "include_host", False)
+
+        if include_host:
+            base = self.request.protocol + "://" + self.request.host
+        else:
+            base = ""
+
+        return base + get_url(self.settings, path, **kwargs)
+
+    def require_setting(self, name: str, feature: str = "this feature") -> None:
+        """Raises an exception if the given app setting is not defined."""
+        if not self.application.settings.get(name):
+            raise Exception(
+                "You must define the '%s' setting in your "
+                "application to use %s" % (name, feature)
+            )
+
+    def reverse_url(self, name: str, *args: Any) -> str:
+        """Alias for `Application.reverse_url`."""
+        return self.application.reverse_url(name, *args)
+
+    def compute_etag(self) -> Optional[str]:
+        """Computes the etag header to be used for this request.
+
+        By default uses a hash of the content written so far.
+
+        May be overridden to provide custom etag implementations,
+        or may return None to disable tornado's default etag support.
+        """
+        hasher = hashlib.sha1()
+        for part in self._write_buffer:
+            hasher.update(part)
+        return '"%s"' % hasher.hexdigest()
+
+    def set_etag_header(self) -> None:
+        """Sets the response's Etag header using ``self.compute_etag()``.
+
+        Note: no header will be set if ``compute_etag()`` returns ``None``.
+
+        This method is called automatically when the request is finished.
+        """
+        etag = self.compute_etag()
+        if etag is not None:
+            self.set_header("Etag", etag)
+
+    def check_etag_header(self) -> bool:
+        """Checks the ``Etag`` header against requests's ``If-None-Match``.
+
+        Returns ``True`` if the request's Etag matches and a 304 should be
+        returned. For example::
+
+            self.set_etag_header()
+            if self.check_etag_header():
+                self.set_status(304)
+                return
+
+        This method is called automatically when the request is finished,
+        but may be called earlier for applications that override
+        `compute_etag` and want to do an early check for ``If-None-Match``
+        before completing the request.  The ``Etag`` header should be set
+        (perhaps with `set_etag_header`) before calling this method.
+        """
+        computed_etag = utf8(self._headers.get("Etag", ""))
+        # Find all weak and strong etag values from If-None-Match header
+        # because RFC 7232 allows multiple etag values in a single header.
+        etags = re.findall(
+            rb'\*|(?:W/)?"[^"]*"', utf8(self.request.headers.get("If-None-Match", ""))
+        )
+        if not computed_etag or not etags:
+            return False
+
+        match = False
+        if etags[0] == b"*":
+            match = True
+        else:
+            # Use a weak comparison when comparing entity-tags.
+            def val(x: bytes) -> bytes:
+                return x[2:] if x.startswith(b"W/") else x
+
+            for etag in etags:
+                if val(etag) == val(computed_etag):
+                    match = True
+                    break
+        return match
+
+    async def _execute(
+        self, transforms: List["OutputTransform"], *args: bytes, **kwargs: bytes
+    ) -> None:
+        """Executes this request with the given output transforms."""
+        self._transforms = transforms
+        try:
+            if self.request.method not in self.SUPPORTED_METHODS:
+                raise HTTPError(405)
+            self.path_args = [self.decode_argument(arg) for arg in args]
+            self.path_kwargs = dict(
+                (k, self.decode_argument(v, name=k)) for (k, v) in kwargs.items()
+            )
+            # If XSRF cookies are turned on, reject form submissions without
+            # the proper cookie
+            if self.request.method not in (
+                "GET",
+                "HEAD",
+                "OPTIONS",
+            ) and self.application.settings.get("xsrf_cookies"):
+                self.check_xsrf_cookie()
+
+            result = self.prepare()
+            if result is not None:
+                result = await result  # type: ignore
+            if self._prepared_future is not None:
+                # Tell the Application we've finished with prepare()
+                # and are ready for the body to arrive.
+                future_set_result_unless_cancelled(self._prepared_future, None)
+            if self._finished:
+                return
+
+            if _has_stream_request_body(self.__class__):
+                # In streaming mode request.body is a Future that signals
+                # the body has been completely received.  The Future has no
+                # result; the data has been passed to self.data_received
+                # instead.
+                try:
+                    await self.request._body_future
+                except iostream.StreamClosedError:
+                    return
+
+            method = getattr(self, self.request.method.lower())
+            result = method(*self.path_args, **self.path_kwargs)
+            if result is not None:
+                result = await result
+            if self._auto_finish and not self._finished:
+                self.finish()
+        except Exception as e:
+            try:
+                self._handle_request_exception(e)
+            except Exception:
+                app_log.error("Exception in exception handler", exc_info=True)
+            finally:
+                # Unset result to avoid circular references
+                result = None
+            if self._prepared_future is not None and not self._prepared_future.done():
+                # In case we failed before setting _prepared_future, do it
+                # now (to unblock the HTTP server).  Note that this is not
+                # in a finally block to avoid GC issues prior to Python 3.4.
+                self._prepared_future.set_result(None)
+
+    def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
+        """Implement this method to handle streamed request data.
+
+        Requires the `.stream_request_body` decorator.
+
+        May be a coroutine for flow control.
+        """
+        raise NotImplementedError()
+
+    def _log(self) -> None:
+        """Logs the current request.
+
+        Sort of deprecated since this functionality was moved to the
+        Application, but left in place for the benefit of existing apps
+        that have overridden this method.
+        """
+        self.application.log_request(self)
+
+    def _request_summary(self) -> str:
+        return "%s %s (%s)" % (
+            self.request.method,
+            self.request.uri,
+            self.request.remote_ip,
+        )
+
+    def _handle_request_exception(self, e: BaseException) -> None:
+        if isinstance(e, Finish):
+            # Not an error; just finish the request without logging.
+            if not self._finished:
+                self.finish(*e.args)
+            return
+        try:
+            self.log_exception(*sys.exc_info())
+        except Exception:
+            # An error here should still get a best-effort send_error()
+            # to avoid leaking the connection.
+            app_log.error("Error in exception logger", exc_info=True)
+        if self._finished:
+            # Extra errors after the request has been finished should
+            # be logged, but there is no reason to continue to try and
+            # send a response.
+            return
+        if isinstance(e, HTTPError):
+            self.send_error(e.status_code, exc_info=sys.exc_info())
+        else:
+            self.send_error(500, exc_info=sys.exc_info())
+
+    def log_exception(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[TracebackType],
+    ) -> None:
+        """Override to customize logging of uncaught exceptions.
+
+        By default logs instances of `HTTPError` as warnings without
+        stack traces (on the ``tornado.general`` logger), and all
+        other exceptions as errors with stack traces (on the
+        ``tornado.application`` logger).
+
+        .. versionadded:: 3.1
+        """
+        if isinstance(value, HTTPError):
+            if value.log_message:
+                format = "%d %s: " + value.log_message
+                args = [value.status_code, self._request_summary()] + list(value.args)
+                gen_log.warning(format, *args)
+        else:
+            app_log.error(
+                "Uncaught exception %s\n%r",
+                self._request_summary(),
+                self.request,
+                exc_info=(typ, value, tb),  # type: ignore
+            )
+
+    def _ui_module(self, name: str, module: Type["UIModule"]) -> Callable[..., str]:
+        def render(*args, **kwargs) -> str:  # type: ignore
+            if not hasattr(self, "_active_modules"):
+                self._active_modules = {}  # type: Dict[str, UIModule]
+            if name not in self._active_modules:
+                self._active_modules[name] = module(self)
+            rendered = self._active_modules[name].render(*args, **kwargs)
+            return rendered
+
+        return render
+
+    def _ui_method(self, method: Callable[..., str]) -> Callable[..., str]:
+        return lambda *args, **kwargs: method(self, *args, **kwargs)
+
+    def _clear_representation_headers(self) -> None:
+        # 304 responses should not contain representation metadata
+        # headers (defined in
+        # https://tools.ietf.org/html/rfc7231#section-3.1)
+        # not explicitly allowed by
+        # https://tools.ietf.org/html/rfc7232#section-4.1
+        headers = ["Content-Encoding", "Content-Language", "Content-Type"]
+        for h in headers:
+            self.clear_header(h)
+
+
+_RequestHandlerType = TypeVar("_RequestHandlerType", bound=RequestHandler)
+
+
+def stream_request_body(cls: Type[_RequestHandlerType]) -> Type[_RequestHandlerType]:
+    """Apply to `RequestHandler` subclasses to enable streaming body support.
+
+    This decorator implies the following changes:
+
+    * `.HTTPServerRequest.body` is undefined, and body arguments will not
+      be included in `RequestHandler.get_argument`.
+    * `RequestHandler.prepare` is called when the request headers have been
+      read instead of after the entire body has been read.
+    * The subclass must define a method ``data_received(self, data):``, which
+      will be called zero or more times as data is available.  Note that
+      if the request has an empty body, ``data_received`` may not be called.
+    * ``prepare`` and ``data_received`` may return Futures (such as via
+      ``@gen.coroutine``, in which case the next method will not be called
+      until those futures have completed.
+    * The regular HTTP method (``post``, ``put``, etc) will be called after
+      the entire body has been read.
+
+    See the `file receiver demo <https://github.com/tornadoweb/tornado/tree/stable/demos/file_upload/>`_
+    for example usage.
+    """  # noqa: E501
+    if not issubclass(cls, RequestHandler):
+        raise TypeError("expected subclass of RequestHandler, got %r", cls)
+    cls._stream_request_body = True
+    return cls
+
+
+def _has_stream_request_body(cls: Type[RequestHandler]) -> bool:
+    if not issubclass(cls, RequestHandler):
+        raise TypeError("expected subclass of RequestHandler, got %r", cls)
+    return cls._stream_request_body
+
+
+def removeslash(
+    method: Callable[..., Optional[Awaitable[None]]]
+) -> Callable[..., Optional[Awaitable[None]]]:
+    """Use this decorator to remove trailing slashes from the request path.
+
+    For example, a request to ``/foo/`` would redirect to ``/foo`` with this
+    decorator. Your request handler mapping should use a regular expression
+    like ``r'/foo/*'`` in conjunction with using the decorator.
+    """
+
+    @functools.wraps(method)
+    def wrapper(  # type: ignore
+        self: RequestHandler, *args, **kwargs
+    ) -> Optional[Awaitable[None]]:
+        if self.request.path.endswith("/"):
+            if self.request.method in ("GET", "HEAD"):
+                uri = self.request.path.rstrip("/")
+                if uri:  # don't try to redirect '/' to ''
+                    if self.request.query:
+                        uri += "?" + self.request.query
+                    self.redirect(uri, permanent=True)
+                    return None
+            else:
+                raise HTTPError(404)
+        return method(self, *args, **kwargs)
+
+    return wrapper
+
+
+def addslash(
+    method: Callable[..., Optional[Awaitable[None]]]
+) -> Callable[..., Optional[Awaitable[None]]]:
+    """Use this decorator to add a missing trailing slash to the request path.
+
+    For example, a request to ``/foo`` would redirect to ``/foo/`` with this
+    decorator. Your request handler mapping should use a regular expression
+    like ``r'/foo/?'`` in conjunction with using the decorator.
+    """
+
+    @functools.wraps(method)
+    def wrapper(  # type: ignore
+        self: RequestHandler, *args, **kwargs
+    ) -> Optional[Awaitable[None]]:
+        if not self.request.path.endswith("/"):
+            if self.request.method in ("GET", "HEAD"):
+                uri = self.request.path + "/"
+                if self.request.query:
+                    uri += "?" + self.request.query
+                self.redirect(uri, permanent=True)
+                return None
+            raise HTTPError(404)
+        return method(self, *args, **kwargs)
+
+    return wrapper
+
+
+class _ApplicationRouter(ReversibleRuleRouter):
+    """Routing implementation used internally by `Application`.
+
+    Provides a binding between `Application` and `RequestHandler`.
+    This implementation extends `~.routing.ReversibleRuleRouter` in a couple of ways:
+        * it allows to use `RequestHandler` subclasses as `~.routing.Rule` target and
+        * it allows to use a list/tuple of rules as `~.routing.Rule` target.
+        ``process_rule`` implementation will substitute this list with an appropriate
+        `_ApplicationRouter` instance.
+    """
+
+    def __init__(
+        self, application: "Application", rules: Optional[_RuleList] = None
+    ) -> None:
+        assert isinstance(application, Application)
+        self.application = application
+        super().__init__(rules)
+
+    def process_rule(self, rule: Rule) -> Rule:
+        rule = super().process_rule(rule)
+
+        if isinstance(rule.target, (list, tuple)):
+            rule.target = _ApplicationRouter(
+                self.application, rule.target  # type: ignore
+            )
+
+        return rule
+
+    def get_target_delegate(
+        self, target: Any, request: httputil.HTTPServerRequest, **target_params: Any
+    ) -> Optional[httputil.HTTPMessageDelegate]:
+        if isclass(target) and issubclass(target, RequestHandler):
+            return self.application.get_handler_delegate(
+                request, target, **target_params
+            )
+
+        return super().get_target_delegate(target, request, **target_params)
+
+
+class Application(ReversibleRouter):
+    r"""A collection of request handlers that make up a web application.
+
+    Instances of this class are callable and can be passed directly to
+    HTTPServer to serve the application::
+
+        application = web.Application([
+            (r"/", MainPageHandler),
+        ])
+        http_server = httpserver.HTTPServer(application)
+        http_server.listen(8080)
+
+    The constructor for this class takes in a list of `~.routing.Rule`
+    objects or tuples of values corresponding to the arguments of
+    `~.routing.Rule` constructor: ``(matcher, target, [target_kwargs], [name])``,
+    the values in square brackets being optional. The default matcher is
+    `~.routing.PathMatches`, so ``(regexp, target)`` tuples can also be used
+    instead of ``(PathMatches(regexp), target)``.
+
+    A common routing target is a `RequestHandler` subclass, but you can also
+    use lists of rules as a target, which create a nested routing configuration::
+
+        application = web.Application([
+            (HostMatches("example.com"), [
+                (r"/", MainPageHandler),
+                (r"/feed", FeedHandler),
+            ]),
+        ])
+
+    In addition to this you can use nested `~.routing.Router` instances,
+    `~.httputil.HTTPMessageDelegate` subclasses and callables as routing targets
+    (see `~.routing` module docs for more information).
+
+    When we receive requests, we iterate over the list in order and
+    instantiate an instance of the first request class whose regexp
+    matches the request path. The request class can be specified as
+    either a class object or a (fully-qualified) name.
+
+    A dictionary may be passed as the third element (``target_kwargs``)
+    of the tuple, which will be used as keyword arguments to the handler's
+    constructor and `~RequestHandler.initialize` method. This pattern
+    is used for the `StaticFileHandler` in this example (note that a
+    `StaticFileHandler` can be installed automatically with the
+    static_path setting described below)::
+
+        application = web.Application([
+            (r"/static/(.*)", web.StaticFileHandler, {"path": "/var/www"}),
+        ])
+
+    We support virtual hosts with the `add_handlers` method, which takes in
+    a host regular expression as the first argument::
+
+        application.add_handlers(r"www\.myhost\.com", [
+            (r"/article/([0-9]+)", ArticleHandler),
+        ])
+
+    If there's no match for the current request's host, then ``default_host``
+    parameter value is matched against host regular expressions.
+
+
+    .. warning::
+
+       Applications that do not use TLS may be vulnerable to :ref:`DNS
+       rebinding <dnsrebinding>` attacks. This attack is especially
+       relevant to applications that only listen on ``127.0.0.1`` or
+       other private networks. Appropriate host patterns must be used
+       (instead of the default of ``r'.*'``) to prevent this risk. The
+       ``default_host`` argument must not be used in applications that
+       may be vulnerable to DNS rebinding.
+
+    You can serve static files by sending the ``static_path`` setting
+    as a keyword argument. We will serve those files from the
+    ``/static/`` URI (this is configurable with the
+    ``static_url_prefix`` setting), and we will serve ``/favicon.ico``
+    and ``/robots.txt`` from the same directory.  A custom subclass of
+    `StaticFileHandler` can be specified with the
+    ``static_handler_class`` setting.
+
+    .. versionchanged:: 4.5
+       Integration with the new `tornado.routing` module.
+
+    """
+
+    def __init__(
+        self,
+        handlers: Optional[_RuleList] = None,
+        default_host: Optional[str] = None,
+        transforms: Optional[List[Type["OutputTransform"]]] = None,
+        **settings: Any,
+    ) -> None:
+        if transforms is None:
+            self.transforms = []  # type: List[Type[OutputTransform]]
+            if settings.get("compress_response") or settings.get("gzip"):
+                self.transforms.append(GZipContentEncoding)
+        else:
+            self.transforms = transforms
+        self.default_host = default_host
+        self.settings = settings
+        self.ui_modules = {
+            "linkify": _linkify,
+            "xsrf_form_html": _xsrf_form_html,
+            "Template": TemplateModule,
+        }
+        self.ui_methods = {}  # type: Dict[str, Callable[..., str]]
+        self._load_ui_modules(settings.get("ui_modules", {}))
+        self._load_ui_methods(settings.get("ui_methods", {}))
+        if self.settings.get("static_path"):
+            path = self.settings["static_path"]
+            handlers = list(handlers or [])
+            static_url_prefix = settings.get("static_url_prefix", "/static/")
+            static_handler_class = settings.get(
+                "static_handler_class", StaticFileHandler
+            )
+            static_handler_args = settings.get("static_handler_args", {})
+            static_handler_args["path"] = path
+            for pattern in [
+                re.escape(static_url_prefix) + r"(.*)",
+                r"/(favicon\.ico)",
+                r"/(robots\.txt)",
+            ]:
+                handlers.insert(0, (pattern, static_handler_class, static_handler_args))
+
+        if self.settings.get("debug"):
+            self.settings.setdefault("autoreload", True)
+            self.settings.setdefault("compiled_template_cache", False)
+            self.settings.setdefault("static_hash_cache", False)
+            self.settings.setdefault("serve_traceback", True)
+
+        self.wildcard_router = _ApplicationRouter(self, handlers)
+        self.default_router = _ApplicationRouter(
+            self, [Rule(AnyMatches(), self.wildcard_router)]
+        )
+
+        # Automatically reload modified modules
+        if self.settings.get("autoreload"):
+            from tornado import autoreload
+
+            autoreload.start()
+
+    def listen(
+        self,
+        port: int,
+        address: Optional[str] = None,
+        *,
+        family: socket.AddressFamily = socket.AF_UNSPEC,
+        backlog: int = tornado.netutil._DEFAULT_BACKLOG,
+        flags: Optional[int] = None,
+        reuse_port: bool = False,
+        **kwargs: Any,
+    ) -> HTTPServer:
+        """Starts an HTTP server for this application on the given port.
+
+        This is a convenience alias for creating an `.HTTPServer` object and
+        calling its listen method.  Keyword arguments not supported by
+        `HTTPServer.listen <.TCPServer.listen>` are passed to the `.HTTPServer`
+        constructor.  For advanced uses (e.g. multi-process mode), do not use
+        this method; create an `.HTTPServer` and call its
+        `.TCPServer.bind`/`.TCPServer.start` methods directly.
+
+        Note that after calling this method you still need to call
+        ``IOLoop.current().start()`` (or run within ``asyncio.run``) to start
+        the server.
+
+        Returns the `.HTTPServer` object.
+
+        .. versionchanged:: 4.3
+           Now returns the `.HTTPServer` object.
+
+        .. versionchanged:: 6.2
+           Added support for new keyword arguments in `.TCPServer.listen`,
+           including ``reuse_port``.
+        """
+        server = HTTPServer(self, **kwargs)
+        server.listen(
+            port,
+            address=address,
+            family=family,
+            backlog=backlog,
+            flags=flags,
+            reuse_port=reuse_port,
+        )
+        return server
+
+    def add_handlers(self, host_pattern: str, host_handlers: _RuleList) -> None:
+        """Appends the given handlers to our handler list.
+
+        Host patterns are processed sequentially in the order they were
+        added. All matching patterns will be considered.
+        """
+        host_matcher = HostMatches(host_pattern)
+        rule = Rule(host_matcher, _ApplicationRouter(self, host_handlers))
+
+        self.default_router.rules.insert(-1, rule)
+
+        if self.default_host is not None:
+            self.wildcard_router.add_rules(
+                [(DefaultHostMatches(self, host_matcher.host_pattern), host_handlers)]
+            )
+
+    def add_transform(self, transform_class: Type["OutputTransform"]) -> None:
+        self.transforms.append(transform_class)
+
+    def _load_ui_methods(self, methods: Any) -> None:
+        if isinstance(methods, types.ModuleType):
+            self._load_ui_methods(dict((n, getattr(methods, n)) for n in dir(methods)))
+        elif isinstance(methods, list):
+            for m in methods:
+                self._load_ui_methods(m)
+        else:
+            for name, fn in methods.items():
+                if (
+                    not name.startswith("_")
+                    and hasattr(fn, "__call__")
+                    and name[0].lower() == name[0]
+                ):
+                    self.ui_methods[name] = fn
+
+    def _load_ui_modules(self, modules: Any) -> None:
+        if isinstance(modules, types.ModuleType):
+            self._load_ui_modules(dict((n, getattr(modules, n)) for n in dir(modules)))
+        elif isinstance(modules, list):
+            for m in modules:
+                self._load_ui_modules(m)
+        else:
+            assert isinstance(modules, dict)
+            for name, cls in modules.items():
+                try:
+                    if issubclass(cls, UIModule):
+                        self.ui_modules[name] = cls
+                except TypeError:
+                    pass
+
+    def __call__(
+        self, request: httputil.HTTPServerRequest
+    ) -> Optional[Awaitable[None]]:
+        # Legacy HTTPServer interface
+        dispatcher = self.find_handler(request)
+        return dispatcher.execute()
+
+    def find_handler(
+        self, request: httputil.HTTPServerRequest, **kwargs: Any
+    ) -> "_HandlerDelegate":
+        route = self.default_router.find_handler(request)
+        if route is not None:
+            return cast("_HandlerDelegate", route)
+
+        if self.settings.get("default_handler_class"):
+            return self.get_handler_delegate(
+                request,
+                self.settings["default_handler_class"],
+                self.settings.get("default_handler_args", {}),
+            )
+
+        return self.get_handler_delegate(request, ErrorHandler, {"status_code": 404})
+
+    def get_handler_delegate(
+        self,
+        request: httputil.HTTPServerRequest,
+        target_class: Type[RequestHandler],
+        target_kwargs: Optional[Dict[str, Any]] = None,
+        path_args: Optional[List[bytes]] = None,
+        path_kwargs: Optional[Dict[str, bytes]] = None,
+    ) -> "_HandlerDelegate":
+        """Returns `~.httputil.HTTPMessageDelegate` that can serve a request
+        for application and `RequestHandler` subclass.
+
+        :arg httputil.HTTPServerRequest request: current HTTP request.
+        :arg RequestHandler target_class: a `RequestHandler` class.
+        :arg dict target_kwargs: keyword arguments for ``target_class`` constructor.
+        :arg list path_args: positional arguments for ``target_class`` HTTP method that
+            will be executed while handling a request (``get``, ``post`` or any other).
+        :arg dict path_kwargs: keyword arguments for ``target_class`` HTTP method.
+        """
+        return _HandlerDelegate(
+            self, request, target_class, target_kwargs, path_args, path_kwargs
+        )
+
+    def reverse_url(self, name: str, *args: Any) -> str:
+        """Returns a URL path for handler named ``name``
+
+        The handler must be added to the application as a named `URLSpec`.
+
+        Args will be substituted for capturing groups in the `URLSpec` regex.
+        They will be converted to strings if necessary, encoded as utf8,
+        and url-escaped.
+        """
+        reversed_url = self.default_router.reverse_url(name, *args)
+        if reversed_url is not None:
+            return reversed_url
+
+        raise KeyError("%s not found in named urls" % name)
+
+    def log_request(self, handler: RequestHandler) -> None:
+        """Writes a completed HTTP request to the logs.
+
+        By default writes to the python root logger.  To change
+        this behavior either subclass Application and override this method,
+        or pass a function in the application settings dictionary as
+        ``log_function``.
+        """
+        if "log_function" in self.settings:
+            self.settings["log_function"](handler)
+            return
+        if handler.get_status() < 400:
+            log_method = access_log.info
+        elif handler.get_status() < 500:
+            log_method = access_log.warning
+        else:
+            log_method = access_log.error
+        request_time = 1000.0 * handler.request.request_time()
+        log_method(
+            "%d %s %.2fms",
+            handler.get_status(),
+            handler._request_summary(),
+            request_time,
+        )
+
+
+class _HandlerDelegate(httputil.HTTPMessageDelegate):
+    def __init__(
+        self,
+        application: Application,
+        request: httputil.HTTPServerRequest,
+        handler_class: Type[RequestHandler],
+        handler_kwargs: Optional[Dict[str, Any]],
+        path_args: Optional[List[bytes]],
+        path_kwargs: Optional[Dict[str, bytes]],
+    ) -> None:
+        self.application = application
+        self.connection = request.connection
+        self.request = request
+        self.handler_class = handler_class
+        self.handler_kwargs = handler_kwargs or {}
+        self.path_args = path_args or []
+        self.path_kwargs = path_kwargs or {}
+        self.chunks = []  # type: List[bytes]
+        self.stream_request_body = _has_stream_request_body(self.handler_class)
+
+    def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> Optional[Awaitable[None]]:
+        if self.stream_request_body:
+            self.request._body_future = Future()
+            return self.execute()
+        return None
+
+    def data_received(self, data: bytes) -> Optional[Awaitable[None]]:
+        if self.stream_request_body:
+            return self.handler.data_received(data)
+        else:
+            self.chunks.append(data)
+            return None
+
+    def finish(self) -> None:
+        if self.stream_request_body:
+            future_set_result_unless_cancelled(self.request._body_future, None)
+        else:
+            self.request.body = b"".join(self.chunks)
+            self.request._parse_body()
+            self.execute()
+
+    def on_connection_close(self) -> None:
+        if self.stream_request_body:
+            self.handler.on_connection_close()
+        else:
+            self.chunks = None  # type: ignore
+
+    def execute(self) -> Optional[Awaitable[None]]:
+        # If template cache is disabled (usually in the debug mode),
+        # re-compile templates and reload static files on every
+        # request so you don't need to restart to see changes
+        if not self.application.settings.get("compiled_template_cache", True):
+            with RequestHandler._template_loader_lock:
+                for loader in RequestHandler._template_loaders.values():
+                    loader.reset()
+        if not self.application.settings.get("static_hash_cache", True):
+            static_handler_class = self.application.settings.get(
+                "static_handler_class", StaticFileHandler
+            )
+            static_handler_class.reset()
+
+        self.handler = self.handler_class(
+            self.application, self.request, **self.handler_kwargs
+        )
+        transforms = [t(self.request) for t in self.application.transforms]
+
+        if self.stream_request_body:
+            self.handler._prepared_future = Future()
+        # Note that if an exception escapes handler._execute it will be
+        # trapped in the Future it returns (which we are ignoring here,
+        # leaving it to be logged when the Future is GC'd).
+        # However, that shouldn't happen because _execute has a blanket
+        # except handler, and we cannot easily access the IOLoop here to
+        # call add_future (because of the requirement to remain compatible
+        # with WSGI)
+        fut = gen.convert_yielded(
+            self.handler._execute(transforms, *self.path_args, **self.path_kwargs)
+        )
+        fut.add_done_callback(lambda f: f.result())
+        # If we are streaming the request body, then execute() is finished
+        # when the handler has prepared to receive the body.  If not,
+        # it doesn't matter when execute() finishes (so we return None)
+        return self.handler._prepared_future
+
+
+class HTTPError(Exception):
+    """An exception that will turn into an HTTP error response.
+
+    Raising an `HTTPError` is a convenient alternative to calling
+    `RequestHandler.send_error` since it automatically ends the
+    current function.
+
+    To customize the response sent with an `HTTPError`, override
+    `RequestHandler.write_error`.
+
+    :arg int status_code: HTTP status code.  Must be listed in
+        `httplib.responses <http.client.responses>` unless the ``reason``
+        keyword argument is given.
+    :arg str log_message: Message to be written to the log for this error
+        (will not be shown to the user unless the `Application` is in debug
+        mode).  May contain ``%s``-style placeholders, which will be filled
+        in with remaining positional parameters.
+    :arg str reason: Keyword-only argument.  The HTTP "reason" phrase
+        to pass in the status line along with ``status_code``.  Normally
+        determined automatically from ``status_code``, but can be used
+        to use a non-standard numeric code.
+    """
+
+    def __init__(
+        self,
+        status_code: int = 500,
+        log_message: Optional[str] = None,
+        *args: Any,
+        **kwargs: Any,
+    ) -> None:
+        self.status_code = status_code
+        self.log_message = log_message
+        self.args = args
+        self.reason = kwargs.get("reason", None)
+        if log_message and not args:
+            self.log_message = log_message.replace("%", "%%")
+
+    def __str__(self) -> str:
+        message = "HTTP %d: %s" % (
+            self.status_code,
+            self.reason or httputil.responses.get(self.status_code, "Unknown"),
+        )
+        if self.log_message:
+            return message + " (" + (self.log_message % self.args) + ")"
+        else:
+            return message
+
+
+class Finish(Exception):
+    """An exception that ends the request without producing an error response.
+
+    When `Finish` is raised in a `RequestHandler`, the request will
+    end (calling `RequestHandler.finish` if it hasn't already been
+    called), but the error-handling methods (including
+    `RequestHandler.write_error`) will not be called.
+
+    If `Finish()` was created with no arguments, the pending response
+    will be sent as-is. If `Finish()` was given an argument, that
+    argument will be passed to `RequestHandler.finish()`.
+
+    This can be a more convenient way to implement custom error pages
+    than overriding ``write_error`` (especially in library code)::
+
+        if self.current_user is None:
+            self.set_status(401)
+            self.set_header('WWW-Authenticate', 'Basic realm="something"')
+            raise Finish()
+
+    .. versionchanged:: 4.3
+       Arguments passed to ``Finish()`` will be passed on to
+       `RequestHandler.finish`.
+    """
+
+    pass
+
+
+class MissingArgumentError(HTTPError):
+    """Exception raised by `RequestHandler.get_argument`.
+
+    This is a subclass of `HTTPError`, so if it is uncaught a 400 response
+    code will be used instead of 500 (and a stack trace will not be logged).
+
+    .. versionadded:: 3.1
+    """
+
+    def __init__(self, arg_name: str) -> None:
+        super().__init__(400, "Missing argument %s" % arg_name)
+        self.arg_name = arg_name
+
+
+class ErrorHandler(RequestHandler):
+    """Generates an error response with ``status_code`` for all requests."""
+
+    def initialize(self, status_code: int) -> None:
+        self.set_status(status_code)
+
+    def prepare(self) -> None:
+        raise HTTPError(self._status_code)
+
+    def check_xsrf_cookie(self) -> None:
+        # POSTs to an ErrorHandler don't actually have side effects,
+        # so we don't need to check the xsrf token.  This allows POSTs
+        # to the wrong url to return a 404 instead of 403.
+        pass
+
+
+class RedirectHandler(RequestHandler):
+    """Redirects the client to the given URL for all GET requests.
+
+    You should provide the keyword argument ``url`` to the handler, e.g.::
+
+        application = web.Application([
+            (r"/oldpath", web.RedirectHandler, {"url": "/newpath"}),
+        ])
+
+    `RedirectHandler` supports regular expression substitutions. E.g., to
+    swap the first and second parts of a path while preserving the remainder::
+
+        application = web.Application([
+            (r"/(.*?)/(.*?)/(.*)", web.RedirectHandler, {"url": "/{1}/{0}/{2}"}),
+        ])
+
+    The final URL is formatted with `str.format` and the substrings that match
+    the capturing groups. In the above example, a request to "/a/b/c" would be
+    formatted like::
+
+        str.format("/{1}/{0}/{2}", "a", "b", "c")  # -> "/b/a/c"
+
+    Use Python's :ref:`format string syntax <formatstrings>` to customize how
+    values are substituted.
+
+    .. versionchanged:: 4.5
+       Added support for substitutions into the destination URL.
+
+    .. versionchanged:: 5.0
+       If any query arguments are present, they will be copied to the
+       destination URL.
+    """
+
+    def initialize(self, url: str, permanent: bool = True) -> None:
+        self._url = url
+        self._permanent = permanent
+
+    def get(self, *args: Any, **kwargs: Any) -> None:
+        to_url = self._url.format(*args, **kwargs)
+        if self.request.query_arguments:
+            # TODO: figure out typing for the next line.
+            to_url = httputil.url_concat(
+                to_url,
+                list(httputil.qs_to_qsl(self.request.query_arguments)),  # type: ignore
+            )
+        self.redirect(to_url, permanent=self._permanent)
+
+
+class StaticFileHandler(RequestHandler):
+    """A simple handler that can serve static content from a directory.
+
+    A `StaticFileHandler` is configured automatically if you pass the
+    ``static_path`` keyword argument to `Application`.  This handler
+    can be customized with the ``static_url_prefix``, ``static_handler_class``,
+    and ``static_handler_args`` settings.
+
+    To map an additional path to this handler for a static data directory
+    you would add a line to your application like::
+
+        application = web.Application([
+            (r"/content/(.*)", web.StaticFileHandler, {"path": "/var/www"}),
+        ])
+
+    The handler constructor requires a ``path`` argument, which specifies the
+    local root directory of the content to be served.
+
+    Note that a capture group in the regex is required to parse the value for
+    the ``path`` argument to the get() method (different than the constructor
+    argument above); see `URLSpec` for details.
+
+    To serve a file like ``index.html`` automatically when a directory is
+    requested, set ``static_handler_args=dict(default_filename="index.html")``
+    in your application settings, or add ``default_filename`` as an initializer
+    argument for your ``StaticFileHandler``.
+
+    To maximize the effectiveness of browser caching, this class supports
+    versioned urls (by default using the argument ``?v=``).  If a version
+    is given, we instruct the browser to cache this file indefinitely.
+    `make_static_url` (also available as `RequestHandler.static_url`) can
+    be used to construct a versioned url.
+
+    This handler is intended primarily for use in development and light-duty
+    file serving; for heavy traffic it will be more efficient to use
+    a dedicated static file server (such as nginx or Apache).  We support
+    the HTTP ``Accept-Ranges`` mechanism to return partial content (because
+    some browsers require this functionality to be present to seek in
+    HTML5 audio or video).
+
+    **Subclassing notes**
+
+    This class is designed to be extensible by subclassing, but because
+    of the way static urls are generated with class methods rather than
+    instance methods, the inheritance patterns are somewhat unusual.
+    Be sure to use the ``@classmethod`` decorator when overriding a
+    class method.  Instance methods may use the attributes ``self.path``
+    ``self.absolute_path``, and ``self.modified``.
+
+    Subclasses should only override methods discussed in this section;
+    overriding other methods is error-prone.  Overriding
+    ``StaticFileHandler.get`` is particularly problematic due to the
+    tight coupling with ``compute_etag`` and other methods.
+
+    To change the way static urls are generated (e.g. to match the behavior
+    of another server or CDN), override `make_static_url`, `parse_url_path`,
+    `get_cache_time`, and/or `get_version`.
+
+    To replace all interaction with the filesystem (e.g. to serve
+    static content from a database), override `get_content`,
+    `get_content_size`, `get_modified_time`, `get_absolute_path`, and
+    `validate_absolute_path`.
+
+    .. versionchanged:: 3.1
+       Many of the methods for subclasses were added in Tornado 3.1.
+    """
+
+    CACHE_MAX_AGE = 86400 * 365 * 10  # 10 years
+
+    _static_hashes = {}  # type: Dict[str, Optional[str]]
+    _lock = threading.Lock()  # protects _static_hashes
+
+    def initialize(self, path: str, default_filename: Optional[str] = None) -> None:
+        self.root = path
+        self.default_filename = default_filename
+
+    @classmethod
+    def reset(cls) -> None:
+        with cls._lock:
+            cls._static_hashes = {}
+
+    def head(self, path: str) -> Awaitable[None]:
+        return self.get(path, include_body=False)
+
+    async def get(self, path: str, include_body: bool = True) -> None:
+        # Set up our path instance variables.
+        self.path = self.parse_url_path(path)
+        del path  # make sure we don't refer to path instead of self.path again
+        absolute_path = self.get_absolute_path(self.root, self.path)
+        self.absolute_path = self.validate_absolute_path(self.root, absolute_path)
+        if self.absolute_path is None:
+            return
+
+        self.modified = self.get_modified_time()
+        self.set_headers()
+
+        if self.should_return_304():
+            self.set_status(304)
+            return
+
+        request_range = None
+        range_header = self.request.headers.get("Range")
+        if range_header:
+            # As per RFC 2616 14.16, if an invalid Range header is specified,
+            # the request will be treated as if the header didn't exist.
+            request_range = httputil._parse_request_range(range_header)
+
+        size = self.get_content_size()
+        if request_range:
+            start, end = request_range
+            if start is not None and start < 0:
+                start += size
+                if start < 0:
+                    start = 0
+            if (
+                start is not None
+                and (start >= size or (end is not None and start >= end))
+            ) or end == 0:
+                # As per RFC 2616 14.35.1, a range is not satisfiable only: if
+                # the first requested byte is equal to or greater than the
+                # content, or when a suffix with length 0 is specified.
+                # https://tools.ietf.org/html/rfc7233#section-2.1
+                # A byte-range-spec is invalid if the last-byte-pos value is present
+                # and less than the first-byte-pos.
+                self.set_status(416)  # Range Not Satisfiable
+                self.set_header("Content-Type", "text/plain")
+                self.set_header("Content-Range", "bytes */%s" % (size,))
+                return
+            if end is not None and end > size:
+                # Clients sometimes blindly use a large range to limit their
+                # download size; cap the endpoint at the actual file size.
+                end = size
+            # Note: only return HTTP 206 if less than the entire range has been
+            # requested. Not only is this semantically correct, but Chrome
+            # refuses to play audio if it gets an HTTP 206 in response to
+            # ``Range: bytes=0-``.
+            if size != (end or size) - (start or 0):
+                self.set_status(206)  # Partial Content
+                self.set_header(
+                    "Content-Range", httputil._get_content_range(start, end, size)
+                )
+        else:
+            start = end = None
+
+        if start is not None and end is not None:
+            content_length = end - start
+        elif end is not None:
+            content_length = end
+        elif start is not None:
+            content_length = size - start
+        else:
+            content_length = size
+        self.set_header("Content-Length", content_length)
+
+        if include_body:
+            content = self.get_content(self.absolute_path, start, end)
+            if isinstance(content, bytes):
+                content = [content]
+            for chunk in content:
+                try:
+                    self.write(chunk)
+                    await self.flush()
+                except iostream.StreamClosedError:
+                    return
+        else:
+            assert self.request.method == "HEAD"
+
+    def compute_etag(self) -> Optional[str]:
+        """Sets the ``Etag`` header based on static url version.
+
+        This allows efficient ``If-None-Match`` checks against cached
+        versions, and sends the correct ``Etag`` for a partial response
+        (i.e. the same ``Etag`` as the full file).
+
+        .. versionadded:: 3.1
+        """
+        assert self.absolute_path is not None
+        version_hash = self._get_cached_version(self.absolute_path)
+        if not version_hash:
+            return None
+        return '"%s"' % (version_hash,)
+
+    def set_headers(self) -> None:
+        """Sets the content and caching headers on the response.
+
+        .. versionadded:: 3.1
+        """
+        self.set_header("Accept-Ranges", "bytes")
+        self.set_etag_header()
+
+        if self.modified is not None:
+            self.set_header("Last-Modified", self.modified)
+
+        content_type = self.get_content_type()
+        if content_type:
+            self.set_header("Content-Type", content_type)
+
+        cache_time = self.get_cache_time(self.path, self.modified, content_type)
+        if cache_time > 0:
+            self.set_header(
+                "Expires",
+                datetime.datetime.utcnow() + datetime.timedelta(seconds=cache_time),
+            )
+            self.set_header("Cache-Control", "max-age=" + str(cache_time))
+
+        self.set_extra_headers(self.path)
+
+    def should_return_304(self) -> bool:
+        """Returns True if the headers indicate that we should return 304.
+
+        .. versionadded:: 3.1
+        """
+        # If client sent If-None-Match, use it, ignore If-Modified-Since
+        if self.request.headers.get("If-None-Match"):
+            return self.check_etag_header()
+
+        # Check the If-Modified-Since, and don't send the result if the
+        # content has not been modified
+        ims_value = self.request.headers.get("If-Modified-Since")
+        if ims_value is not None:
+            date_tuple = email.utils.parsedate(ims_value)
+            if date_tuple is not None:
+                if_since = datetime.datetime(*date_tuple[:6])
+                assert self.modified is not None
+                if if_since >= self.modified:
+                    return True
+
+        return False
+
+    @classmethod
+    def get_absolute_path(cls, root: str, path: str) -> str:
+        """Returns the absolute location of ``path`` relative to ``root``.
+
+        ``root`` is the path configured for this `StaticFileHandler`
+        (in most cases the ``static_path`` `Application` setting).
+
+        This class method may be overridden in subclasses.  By default
+        it returns a filesystem path, but other strings may be used
+        as long as they are unique and understood by the subclass's
+        overridden `get_content`.
+
+        .. versionadded:: 3.1
+        """
+        abspath = os.path.abspath(os.path.join(root, path))
+        return abspath
+
+    def validate_absolute_path(self, root: str, absolute_path: str) -> Optional[str]:
+        """Validate and return the absolute path.
+
+        ``root`` is the configured path for the `StaticFileHandler`,
+        and ``path`` is the result of `get_absolute_path`
+
+        This is an instance method called during request processing,
+        so it may raise `HTTPError` or use methods like
+        `RequestHandler.redirect` (return None after redirecting to
+        halt further processing).  This is where 404 errors for missing files
+        are generated.
+
+        This method may modify the path before returning it, but note that
+        any such modifications will not be understood by `make_static_url`.
+
+        In instance methods, this method's result is available as
+        ``self.absolute_path``.
+
+        .. versionadded:: 3.1
+        """
+        # os.path.abspath strips a trailing /.
+        # We must add it back to `root` so that we only match files
+        # in a directory named `root` instead of files starting with
+        # that prefix.
+        root = os.path.abspath(root)
+        if not root.endswith(os.path.sep):
+            # abspath always removes a trailing slash, except when
+            # root is '/'. This is an unusual case, but several projects
+            # have independently discovered this technique to disable
+            # Tornado's path validation and (hopefully) do their own,
+            # so we need to support it.
+            root += os.path.sep
+        # The trailing slash also needs to be temporarily added back
+        # the requested path so a request to root/ will match.
+        if not (absolute_path + os.path.sep).startswith(root):
+            raise HTTPError(403, "%s is not in root static directory", self.path)
+        if os.path.isdir(absolute_path) and self.default_filename is not None:
+            # need to look at the request.path here for when path is empty
+            # but there is some prefix to the path that was already
+            # trimmed by the routing
+            if not self.request.path.endswith("/"):
+                self.redirect(self.request.path + "/", permanent=True)
+                return None
+            absolute_path = os.path.join(absolute_path, self.default_filename)
+        if not os.path.exists(absolute_path):
+            raise HTTPError(404)
+        if not os.path.isfile(absolute_path):
+            raise HTTPError(403, "%s is not a file", self.path)
+        return absolute_path
+
+    @classmethod
+    def get_content(
+        cls, abspath: str, start: Optional[int] = None, end: Optional[int] = None
+    ) -> Generator[bytes, None, None]:
+        """Retrieve the content of the requested resource which is located
+        at the given absolute path.
+
+        This class method may be overridden by subclasses.  Note that its
+        signature is different from other overridable class methods
+        (no ``settings`` argument); this is deliberate to ensure that
+        ``abspath`` is able to stand on its own as a cache key.
+
+        This method should either return a byte string or an iterator
+        of byte strings.  The latter is preferred for large files
+        as it helps reduce memory fragmentation.
+
+        .. versionadded:: 3.1
+        """
+        with open(abspath, "rb") as file:
+            if start is not None:
+                file.seek(start)
+            if end is not None:
+                remaining = end - (start or 0)  # type: Optional[int]
+            else:
+                remaining = None
+            while True:
+                chunk_size = 64 * 1024
+                if remaining is not None and remaining < chunk_size:
+                    chunk_size = remaining
+                chunk = file.read(chunk_size)
+                if chunk:
+                    if remaining is not None:
+                        remaining -= len(chunk)
+                    yield chunk
+                else:
+                    if remaining is not None:
+                        assert remaining == 0
+                    return
+
+    @classmethod
+    def get_content_version(cls, abspath: str) -> str:
+        """Returns a version string for the resource at the given path.
+
+        This class method may be overridden by subclasses.  The
+        default implementation is a SHA-512 hash of the file's contents.
+
+        .. versionadded:: 3.1
+        """
+        data = cls.get_content(abspath)
+        hasher = hashlib.sha512()
+        if isinstance(data, bytes):
+            hasher.update(data)
+        else:
+            for chunk in data:
+                hasher.update(chunk)
+        return hasher.hexdigest()
+
+    def _stat(self) -> os.stat_result:
+        assert self.absolute_path is not None
+        if not hasattr(self, "_stat_result"):
+            self._stat_result = os.stat(self.absolute_path)
+        return self._stat_result
+
+    def get_content_size(self) -> int:
+        """Retrieve the total size of the resource at the given path.
+
+        This method may be overridden by subclasses.
+
+        .. versionadded:: 3.1
+
+        .. versionchanged:: 4.0
+           This method is now always called, instead of only when
+           partial results are requested.
+        """
+        stat_result = self._stat()
+        return stat_result.st_size
+
+    def get_modified_time(self) -> Optional[datetime.datetime]:
+        """Returns the time that ``self.absolute_path`` was last modified.
+
+        May be overridden in subclasses.  Should return a `~datetime.datetime`
+        object or None.
+
+        .. versionadded:: 3.1
+        """
+        stat_result = self._stat()
+        # NOTE: Historically, this used stat_result[stat.ST_MTIME],
+        # which truncates the fractional portion of the timestamp. It
+        # was changed from that form to stat_result.st_mtime to
+        # satisfy mypy (which disallows the bracket operator), but the
+        # latter form returns a float instead of an int. For
+        # consistency with the past (and because we have a unit test
+        # that relies on this), we truncate the float here, although
+        # I'm not sure that's the right thing to do.
+        modified = datetime.datetime.utcfromtimestamp(int(stat_result.st_mtime))
+        return modified
+
+    def get_content_type(self) -> str:
+        """Returns the ``Content-Type`` header to be used for this request.
+
+        .. versionadded:: 3.1
+        """
+        assert self.absolute_path is not None
+        mime_type, encoding = mimetypes.guess_type(self.absolute_path)
+        # per RFC 6713, use the appropriate type for a gzip compressed file
+        if encoding == "gzip":
+            return "application/gzip"
+        # As of 2015-07-21 there is no bzip2 encoding defined at
+        # http://www.iana.org/assignments/media-types/media-types.xhtml
+        # So for that (and any other encoding), use octet-stream.
+        elif encoding is not None:
+            return "application/octet-stream"
+        elif mime_type is not None:
+            return mime_type
+        # if mime_type not detected, use application/octet-stream
+        else:
+            return "application/octet-stream"
+
+    def set_extra_headers(self, path: str) -> None:
+        """For subclass to add extra headers to the response"""
+        pass
+
+    def get_cache_time(
+        self, path: str, modified: Optional[datetime.datetime], mime_type: str
+    ) -> int:
+        """Override to customize cache control behavior.
+
+        Return a positive number of seconds to make the result
+        cacheable for that amount of time or 0 to mark resource as
+        cacheable for an unspecified amount of time (subject to
+        browser heuristics).
+
+        By default returns cache expiry of 10 years for resources requested
+        with ``v`` argument.
+        """
+        return self.CACHE_MAX_AGE if "v" in self.request.arguments else 0
+
+    @classmethod
+    def make_static_url(
+        cls, settings: Dict[str, Any], path: str, include_version: bool = True
+    ) -> str:
+        """Constructs a versioned url for the given path.
+
+        This method may be overridden in subclasses (but note that it
+        is a class method rather than an instance method).  Subclasses
+        are only required to implement the signature
+        ``make_static_url(cls, settings, path)``; other keyword
+        arguments may be passed through `~RequestHandler.static_url`
+        but are not standard.
+
+        ``settings`` is the `Application.settings` dictionary.  ``path``
+        is the static path being requested.  The url returned should be
+        relative to the current host.
+
+        ``include_version`` determines whether the generated URL should
+        include the query string containing the version hash of the
+        file corresponding to the given ``path``.
+
+        """
+        url = settings.get("static_url_prefix", "/static/") + path
+        if not include_version:
+            return url
+
+        version_hash = cls.get_version(settings, path)
+        if not version_hash:
+            return url
+
+        return "%s?v=%s" % (url, version_hash)
+
+    def parse_url_path(self, url_path: str) -> str:
+        """Converts a static URL path into a filesystem path.
+
+        ``url_path`` is the path component of the URL with
+        ``static_url_prefix`` removed.  The return value should be
+        filesystem path relative to ``static_path``.
+
+        This is the inverse of `make_static_url`.
+        """
+        if os.path.sep != "/":
+            url_path = url_path.replace("/", os.path.sep)
+        return url_path
+
+    @classmethod
+    def get_version(cls, settings: Dict[str, Any], path: str) -> Optional[str]:
+        """Generate the version string to be used in static URLs.
+
+        ``settings`` is the `Application.settings` dictionary and ``path``
+        is the relative location of the requested asset on the filesystem.
+        The returned value should be a string, or ``None`` if no version
+        could be determined.
+
+        .. versionchanged:: 3.1
+           This method was previously recommended for subclasses to override;
+           `get_content_version` is now preferred as it allows the base
+           class to handle caching of the result.
+        """
+        abs_path = cls.get_absolute_path(settings["static_path"], path)
+        return cls._get_cached_version(abs_path)
+
+    @classmethod
+    def _get_cached_version(cls, abs_path: str) -> Optional[str]:
+        with cls._lock:
+            hashes = cls._static_hashes
+            if abs_path not in hashes:
+                try:
+                    hashes[abs_path] = cls.get_content_version(abs_path)
+                except Exception:
+                    gen_log.error("Could not open static file %r", abs_path)
+                    hashes[abs_path] = None
+            hsh = hashes.get(abs_path)
+            if hsh:
+                return hsh
+        return None
+
+
+class FallbackHandler(RequestHandler):
+    """A `RequestHandler` that wraps another HTTP server callback.
+
+    The fallback is a callable object that accepts an
+    `~.httputil.HTTPServerRequest`, such as an `Application` or
+    `tornado.wsgi.WSGIContainer`.  This is most useful to use both
+    Tornado ``RequestHandlers`` and WSGI in the same server.  Typical
+    usage::
+
+        wsgi_app = tornado.wsgi.WSGIContainer(
+            django.core.handlers.wsgi.WSGIHandler())
+        application = tornado.web.Application([
+            (r"/foo", FooHandler),
+            (r".*", FallbackHandler, dict(fallback=wsgi_app),
+        ])
+    """
+
+    def initialize(
+        self, fallback: Callable[[httputil.HTTPServerRequest], None]
+    ) -> None:
+        self.fallback = fallback
+
+    def prepare(self) -> None:
+        self.fallback(self.request)
+        self._finished = True
+        self.on_finish()
+
+
+class OutputTransform(object):
+    """A transform modifies the result of an HTTP request (e.g., GZip encoding)
+
+    Applications are not expected to create their own OutputTransforms
+    or interact with them directly; the framework chooses which transforms
+    (if any) to apply.
+    """
+
+    def __init__(self, request: httputil.HTTPServerRequest) -> None:
+        pass
+
+    def transform_first_chunk(
+        self,
+        status_code: int,
+        headers: httputil.HTTPHeaders,
+        chunk: bytes,
+        finishing: bool,
+    ) -> Tuple[int, httputil.HTTPHeaders, bytes]:
+        return status_code, headers, chunk
+
+    def transform_chunk(self, chunk: bytes, finishing: bool) -> bytes:
+        return chunk
+
+
+class GZipContentEncoding(OutputTransform):
+    """Applies the gzip content encoding to the response.
+
+    See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11
+
+    .. versionchanged:: 4.0
+        Now compresses all mime types beginning with ``text/``, instead
+        of just a whitelist. (the whitelist is still used for certain
+        non-text mime types).
+    """
+
+    # Whitelist of compressible mime types (in addition to any types
+    # beginning with "text/").
+    CONTENT_TYPES = set(
+        [
+            "application/javascript",
+            "application/x-javascript",
+            "application/xml",
+            "application/atom+xml",
+            "application/json",
+            "application/xhtml+xml",
+            "image/svg+xml",
+        ]
+    )
+    # Python's GzipFile defaults to level 9, while most other gzip
+    # tools (including gzip itself) default to 6, which is probably a
+    # better CPU/size tradeoff.
+    GZIP_LEVEL = 6
+    # Responses that are too short are unlikely to benefit from gzipping
+    # after considering the "Content-Encoding: gzip" header and the header
+    # inside the gzip encoding.
+    # Note that responses written in multiple chunks will be compressed
+    # regardless of size.
+    MIN_LENGTH = 1024
+
+    def __init__(self, request: httputil.HTTPServerRequest) -> None:
+        self._gzipping = "gzip" in request.headers.get("Accept-Encoding", "")
+
+    def _compressible_type(self, ctype: str) -> bool:
+        return ctype.startswith("text/") or ctype in self.CONTENT_TYPES
+
+    def transform_first_chunk(
+        self,
+        status_code: int,
+        headers: httputil.HTTPHeaders,
+        chunk: bytes,
+        finishing: bool,
+    ) -> Tuple[int, httputil.HTTPHeaders, bytes]:
+        # TODO: can/should this type be inherited from the superclass?
+        if "Vary" in headers:
+            headers["Vary"] += ", Accept-Encoding"
+        else:
+            headers["Vary"] = "Accept-Encoding"
+        if self._gzipping:
+            ctype = _unicode(headers.get("Content-Type", "")).split(";")[0]
+            self._gzipping = (
+                self._compressible_type(ctype)
+                and (not finishing or len(chunk) >= self.MIN_LENGTH)
+                and ("Content-Encoding" not in headers)
+            )
+        if self._gzipping:
+            headers["Content-Encoding"] = "gzip"
+            self._gzip_value = BytesIO()
+            self._gzip_file = gzip.GzipFile(
+                mode="w", fileobj=self._gzip_value, compresslevel=self.GZIP_LEVEL
+            )
+            chunk = self.transform_chunk(chunk, finishing)
+            if "Content-Length" in headers:
+                # The original content length is no longer correct.
+                # If this is the last (and only) chunk, we can set the new
+                # content-length; otherwise we remove it and fall back to
+                # chunked encoding.
+                if finishing:
+                    headers["Content-Length"] = str(len(chunk))
+                else:
+                    del headers["Content-Length"]
+        return status_code, headers, chunk
+
+    def transform_chunk(self, chunk: bytes, finishing: bool) -> bytes:
+        if self._gzipping:
+            self._gzip_file.write(chunk)
+            if finishing:
+                self._gzip_file.close()
+            else:
+                self._gzip_file.flush()
+            chunk = self._gzip_value.getvalue()
+            self._gzip_value.truncate(0)
+            self._gzip_value.seek(0)
+        return chunk
+
+
+def authenticated(
+    method: Callable[..., Optional[Awaitable[None]]]
+) -> Callable[..., Optional[Awaitable[None]]]:
+    """Decorate methods with this to require that the user be logged in.
+
+    If the user is not logged in, they will be redirected to the configured
+    `login url <RequestHandler.get_login_url>`.
+
+    If you configure a login url with a query parameter, Tornado will
+    assume you know what you're doing and use it as-is.  If not, it
+    will add a `next` parameter so the login page knows where to send
+    you once you're logged in.
+    """
+
+    @functools.wraps(method)
+    def wrapper(  # type: ignore
+        self: RequestHandler, *args, **kwargs
+    ) -> Optional[Awaitable[None]]:
+        if not self.current_user:
+            if self.request.method in ("GET", "HEAD"):
+                url = self.get_login_url()
+                if "?" not in url:
+                    if urllib.parse.urlsplit(url).scheme:
+                        # if login url is absolute, make next absolute too
+                        next_url = self.request.full_url()
+                    else:
+                        assert self.request.uri is not None
+                        next_url = self.request.uri
+                    url += "?" + urlencode(dict(next=next_url))
+                self.redirect(url)
+                return None
+            raise HTTPError(403)
+        return method(self, *args, **kwargs)
+
+    return wrapper
+
+
+class UIModule(object):
+    """A re-usable, modular UI unit on a page.
+
+    UI modules often execute additional queries, and they can include
+    additional CSS and JavaScript that will be included in the output
+    page, which is automatically inserted on page render.
+
+    Subclasses of UIModule must override the `render` method.
+    """
+
+    def __init__(self, handler: RequestHandler) -> None:
+        self.handler = handler
+        self.request = handler.request
+        self.ui = handler.ui
+        self.locale = handler.locale
+
+    @property
+    def current_user(self) -> Any:
+        return self.handler.current_user
+
+    def render(self, *args: Any, **kwargs: Any) -> str:
+        """Override in subclasses to return this module's output."""
+        raise NotImplementedError()
+
+    def embedded_javascript(self) -> Optional[str]:
+        """Override to return a JavaScript string
+        to be embedded in the page."""
+        return None
+
+    def javascript_files(self) -> Optional[Iterable[str]]:
+        """Override to return a list of JavaScript files needed by this module.
+
+        If the return values are relative paths, they will be passed to
+        `RequestHandler.static_url`; otherwise they will be used as-is.
+        """
+        return None
+
+    def embedded_css(self) -> Optional[str]:
+        """Override to return a CSS string
+        that will be embedded in the page."""
+        return None
+
+    def css_files(self) -> Optional[Iterable[str]]:
+        """Override to returns a list of CSS files required by this module.
+
+        If the return values are relative paths, they will be passed to
+        `RequestHandler.static_url`; otherwise they will be used as-is.
+        """
+        return None
+
+    def html_head(self) -> Optional[str]:
+        """Override to return an HTML string that will be put in the <head/>
+        element.
+        """
+        return None
+
+    def html_body(self) -> Optional[str]:
+        """Override to return an HTML string that will be put at the end of
+        the <body/> element.
+        """
+        return None
+
+    def render_string(self, path: str, **kwargs: Any) -> bytes:
+        """Renders a template and returns it as a string."""
+        return self.handler.render_string(path, **kwargs)
+
+
+class _linkify(UIModule):
+    def render(self, text: str, **kwargs: Any) -> str:  # type: ignore
+        return escape.linkify(text, **kwargs)
+
+
+class _xsrf_form_html(UIModule):
+    def render(self) -> str:  # type: ignore
+        return self.handler.xsrf_form_html()
+
+
+class TemplateModule(UIModule):
+    """UIModule that simply renders the given template.
+
+    {% module Template("foo.html") %} is similar to {% include "foo.html" %},
+    but the module version gets its own namespace (with kwargs passed to
+    Template()) instead of inheriting the outer template's namespace.
+
+    Templates rendered through this module also get access to UIModule's
+    automatic JavaScript/CSS features.  Simply call set_resources
+    inside the template and give it keyword arguments corresponding to
+    the methods on UIModule: {{ set_resources(js_files=static_url("my.js")) }}
+    Note that these resources are output once per template file, not once
+    per instantiation of the template, so they must not depend on
+    any arguments to the template.
+    """
+
+    def __init__(self, handler: RequestHandler) -> None:
+        super().__init__(handler)
+        # keep resources in both a list and a dict to preserve order
+        self._resource_list = []  # type: List[Dict[str, Any]]
+        self._resource_dict = {}  # type: Dict[str, Dict[str, Any]]
+
+    def render(self, path: str, **kwargs: Any) -> bytes:  # type: ignore
+        def set_resources(**kwargs) -> str:  # type: ignore
+            if path not in self._resource_dict:
+                self._resource_list.append(kwargs)
+                self._resource_dict[path] = kwargs
+            else:
+                if self._resource_dict[path] != kwargs:
+                    raise ValueError(
+                        "set_resources called with different "
+                        "resources for the same template"
+                    )
+            return ""
+
+        return self.render_string(path, set_resources=set_resources, **kwargs)
+
+    def _get_resources(self, key: str) -> Iterable[str]:
+        return (r[key] for r in self._resource_list if key in r)
+
+    def embedded_javascript(self) -> str:
+        return "\n".join(self._get_resources("embedded_javascript"))
+
+    def javascript_files(self) -> Iterable[str]:
+        result = []
+        for f in self._get_resources("javascript_files"):
+            if isinstance(f, (unicode_type, bytes)):
+                result.append(f)
+            else:
+                result.extend(f)
+        return result
+
+    def embedded_css(self) -> str:
+        return "\n".join(self._get_resources("embedded_css"))
+
+    def css_files(self) -> Iterable[str]:
+        result = []
+        for f in self._get_resources("css_files"):
+            if isinstance(f, (unicode_type, bytes)):
+                result.append(f)
+            else:
+                result.extend(f)
+        return result
+
+    def html_head(self) -> str:
+        return "".join(self._get_resources("html_head"))
+
+    def html_body(self) -> str:
+        return "".join(self._get_resources("html_body"))
+
+
+class _UIModuleNamespace(object):
+    """Lazy namespace which creates UIModule proxies bound to a handler."""
+
+    def __init__(
+        self, handler: RequestHandler, ui_modules: Dict[str, Type[UIModule]]
+    ) -> None:
+        self.handler = handler
+        self.ui_modules = ui_modules
+
+    def __getitem__(self, key: str) -> Callable[..., str]:
+        return self.handler._ui_module(key, self.ui_modules[key])
+
+    def __getattr__(self, key: str) -> Callable[..., str]:
+        try:
+            return self[key]
+        except KeyError as e:
+            raise AttributeError(str(e))
+
+
+def create_signed_value(
+    secret: _CookieSecretTypes,
+    name: str,
+    value: Union[str, bytes],
+    version: Optional[int] = None,
+    clock: Optional[Callable[[], float]] = None,
+    key_version: Optional[int] = None,
+) -> bytes:
+    if version is None:
+        version = DEFAULT_SIGNED_VALUE_VERSION
+    if clock is None:
+        clock = time.time
+
+    timestamp = utf8(str(int(clock())))
+    value = base64.b64encode(utf8(value))
+    if version == 1:
+        assert not isinstance(secret, dict)
+        signature = _create_signature_v1(secret, name, value, timestamp)
+        value = b"|".join([value, timestamp, signature])
+        return value
+    elif version == 2:
+        # The v2 format consists of a version number and a series of
+        # length-prefixed fields "%d:%s", the last of which is a
+        # signature, all separated by pipes.  All numbers are in
+        # decimal format with no leading zeros.  The signature is an
+        # HMAC-SHA256 of the whole string up to that point, including
+        # the final pipe.
+        #
+        # The fields are:
+        # - format version (i.e. 2; no length prefix)
+        # - key version (integer, default is 0)
+        # - timestamp (integer seconds since epoch)
+        # - name (not encoded; assumed to be ~alphanumeric)
+        # - value (base64-encoded)
+        # - signature (hex-encoded; no length prefix)
+        def format_field(s: Union[str, bytes]) -> bytes:
+            return utf8("%d:" % len(s)) + utf8(s)
+
+        to_sign = b"|".join(
+            [
+                b"2",
+                format_field(str(key_version or 0)),
+                format_field(timestamp),
+                format_field(name),
+                format_field(value),
+                b"",
+            ]
+        )
+
+        if isinstance(secret, dict):
+            assert (
+                key_version is not None
+            ), "Key version must be set when sign key dict is used"
+            assert version >= 2, "Version must be at least 2 for key version support"
+            secret = secret[key_version]
+
+        signature = _create_signature_v2(secret, to_sign)
+        return to_sign + signature
+    else:
+        raise ValueError("Unsupported version %d" % version)
+
+
+# A leading version number in decimal
+# with no leading zeros, followed by a pipe.
+_signed_value_version_re = re.compile(rb"^([1-9][0-9]*)\|(.*)$")
+
+
+def _get_version(value: bytes) -> int:
+    # Figures out what version value is.  Version 1 did not include an
+    # explicit version field and started with arbitrary base64 data,
+    # which makes this tricky.
+    m = _signed_value_version_re.match(value)
+    if m is None:
+        version = 1
+    else:
+        try:
+            version = int(m.group(1))
+            if version > 999:
+                # Certain payloads from the version-less v1 format may
+                # be parsed as valid integers.  Due to base64 padding
+                # restrictions, this can only happen for numbers whose
+                # length is a multiple of 4, so we can treat all
+                # numbers up to 999 as versions, and for the rest we
+                # fall back to v1 format.
+                version = 1
+        except ValueError:
+            version = 1
+    return version
+
+
+def decode_signed_value(
+    secret: _CookieSecretTypes,
+    name: str,
+    value: Union[None, str, bytes],
+    max_age_days: float = 31,
+    clock: Optional[Callable[[], float]] = None,
+    min_version: Optional[int] = None,
+) -> Optional[bytes]:
+    if clock is None:
+        clock = time.time
+    if min_version is None:
+        min_version = DEFAULT_SIGNED_VALUE_MIN_VERSION
+    if min_version > 2:
+        raise ValueError("Unsupported min_version %d" % min_version)
+    if not value:
+        return None
+
+    value = utf8(value)
+    version = _get_version(value)
+
+    if version < min_version:
+        return None
+    if version == 1:
+        assert not isinstance(secret, dict)
+        return _decode_signed_value_v1(secret, name, value, max_age_days, clock)
+    elif version == 2:
+        return _decode_signed_value_v2(secret, name, value, max_age_days, clock)
+    else:
+        return None
+
+
+def _decode_signed_value_v1(
+    secret: Union[str, bytes],
+    name: str,
+    value: bytes,
+    max_age_days: float,
+    clock: Callable[[], float],
+) -> Optional[bytes]:
+    parts = utf8(value).split(b"|")
+    if len(parts) != 3:
+        return None
+    signature = _create_signature_v1(secret, name, parts[0], parts[1])
+    if not hmac.compare_digest(parts[2], signature):
+        gen_log.warning("Invalid cookie signature %r", value)
+        return None
+    timestamp = int(parts[1])
+    if timestamp < clock() - max_age_days * 86400:
+        gen_log.warning("Expired cookie %r", value)
+        return None
+    if timestamp > clock() + 31 * 86400:
+        # _cookie_signature does not hash a delimiter between the
+        # parts of the cookie, so an attacker could transfer trailing
+        # digits from the payload to the timestamp without altering the
+        # signature.  For backwards compatibility, sanity-check timestamp
+        # here instead of modifying _cookie_signature.
+        gen_log.warning("Cookie timestamp in future; possible tampering %r", value)
+        return None
+    if parts[1].startswith(b"0"):
+        gen_log.warning("Tampered cookie %r", value)
+        return None
+    try:
+        return base64.b64decode(parts[0])
+    except Exception:
+        return None
+
+
+def _decode_fields_v2(value: bytes) -> Tuple[int, bytes, bytes, bytes, bytes]:
+    def _consume_field(s: bytes) -> Tuple[bytes, bytes]:
+        length, _, rest = s.partition(b":")
+        n = int(length)
+        field_value = rest[:n]
+        # In python 3, indexing bytes returns small integers; we must
+        # use a slice to get a byte string as in python 2.
+        if rest[n : n + 1] != b"|":
+            raise ValueError("malformed v2 signed value field")
+        rest = rest[n + 1 :]
+        return field_value, rest
+
+    rest = value[2:]  # remove version number
+    key_version, rest = _consume_field(rest)
+    timestamp, rest = _consume_field(rest)
+    name_field, rest = _consume_field(rest)
+    value_field, passed_sig = _consume_field(rest)
+    return int(key_version), timestamp, name_field, value_field, passed_sig
+
+
+def _decode_signed_value_v2(
+    secret: _CookieSecretTypes,
+    name: str,
+    value: bytes,
+    max_age_days: float,
+    clock: Callable[[], float],
+) -> Optional[bytes]:
+    try:
+        (
+            key_version,
+            timestamp_bytes,
+            name_field,
+            value_field,
+            passed_sig,
+        ) = _decode_fields_v2(value)
+    except ValueError:
+        return None
+    signed_string = value[: -len(passed_sig)]
+
+    if isinstance(secret, dict):
+        try:
+            secret = secret[key_version]
+        except KeyError:
+            return None
+
+    expected_sig = _create_signature_v2(secret, signed_string)
+    if not hmac.compare_digest(passed_sig, expected_sig):
+        return None
+    if name_field != utf8(name):
+        return None
+    timestamp = int(timestamp_bytes)
+    if timestamp < clock() - max_age_days * 86400:
+        # The signature has expired.
+        return None
+    try:
+        return base64.b64decode(value_field)
+    except Exception:
+        return None
+
+
+def get_signature_key_version(value: Union[str, bytes]) -> Optional[int]:
+    value = utf8(value)
+    version = _get_version(value)
+    if version < 2:
+        return None
+    try:
+        key_version, _, _, _, _ = _decode_fields_v2(value)
+    except ValueError:
+        return None
+
+    return key_version
+
+
+def _create_signature_v1(secret: Union[str, bytes], *parts: Union[str, bytes]) -> bytes:
+    hash = hmac.new(utf8(secret), digestmod=hashlib.sha1)
+    for part in parts:
+        hash.update(utf8(part))
+    return utf8(hash.hexdigest())
+
+
+def _create_signature_v2(secret: Union[str, bytes], s: bytes) -> bytes:
+    hash = hmac.new(utf8(secret), digestmod=hashlib.sha256)
+    hash.update(utf8(s))
+    return utf8(hash.hexdigest())
+
+
+def is_absolute(path: str) -> bool:
+    return any(path.startswith(x) for x in ["/", "http:", "https:"])
diff --git a/venv/lib/python3.9/site-packages/tornado/websocket.py b/venv/lib/python3.9/site-packages/tornado/websocket.py
new file mode 100644
index 00000000..d0abd425
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/websocket.py
@@ -0,0 +1,1659 @@
+"""Implementation of the WebSocket protocol.
+
+`WebSockets <http://dev.w3.org/html5/websockets/>`_ allow for bidirectional
+communication between the browser and server. WebSockets are supported in the
+current versions of all major browsers.
+
+This module implements the final version of the WebSocket protocol as
+defined in `RFC 6455 <http://tools.ietf.org/html/rfc6455>`_.
+
+.. versionchanged:: 4.0
+   Removed support for the draft 76 protocol version.
+"""
+
+import abc
+import asyncio
+import base64
+import hashlib
+import os
+import sys
+import struct
+import tornado
+from urllib.parse import urlparse
+import zlib
+
+from tornado.concurrent import Future, future_set_result_unless_cancelled
+from tornado.escape import utf8, native_str, to_unicode
+from tornado import gen, httpclient, httputil
+from tornado.ioloop import IOLoop, PeriodicCallback
+from tornado.iostream import StreamClosedError, IOStream
+from tornado.log import gen_log, app_log
+from tornado.netutil import Resolver
+from tornado import simple_httpclient
+from tornado.queues import Queue
+from tornado.tcpclient import TCPClient
+from tornado.util import _websocket_mask
+
+from typing import (
+    TYPE_CHECKING,
+    cast,
+    Any,
+    Optional,
+    Dict,
+    Union,
+    List,
+    Awaitable,
+    Callable,
+    Tuple,
+    Type,
+)
+from types import TracebackType
+
+if TYPE_CHECKING:
+    from typing_extensions import Protocol
+
+    # The zlib compressor types aren't actually exposed anywhere
+    # publicly, so declare protocols for the portions we use.
+    class _Compressor(Protocol):
+        def compress(self, data: bytes) -> bytes:
+            pass
+
+        def flush(self, mode: int) -> bytes:
+            pass
+
+    class _Decompressor(Protocol):
+        unconsumed_tail = b""  # type: bytes
+
+        def decompress(self, data: bytes, max_length: int) -> bytes:
+            pass
+
+    class _WebSocketDelegate(Protocol):
+        # The common base interface implemented by WebSocketHandler on
+        # the server side and WebSocketClientConnection on the client
+        # side.
+        def on_ws_connection_close(
+            self, close_code: Optional[int] = None, close_reason: Optional[str] = None
+        ) -> None:
+            pass
+
+        def on_message(self, message: Union[str, bytes]) -> Optional["Awaitable[None]"]:
+            pass
+
+        def on_ping(self, data: bytes) -> None:
+            pass
+
+        def on_pong(self, data: bytes) -> None:
+            pass
+
+        def log_exception(
+            self,
+            typ: Optional[Type[BaseException]],
+            value: Optional[BaseException],
+            tb: Optional[TracebackType],
+        ) -> None:
+            pass
+
+
+_default_max_message_size = 10 * 1024 * 1024
+
+
+class WebSocketError(Exception):
+    pass
+
+
+class WebSocketClosedError(WebSocketError):
+    """Raised by operations on a closed connection.
+
+    .. versionadded:: 3.2
+    """
+
+    pass
+
+
+class _DecompressTooLargeError(Exception):
+    pass
+
+
+class _WebSocketParams(object):
+    def __init__(
+        self,
+        ping_interval: Optional[float] = None,
+        ping_timeout: Optional[float] = None,
+        max_message_size: int = _default_max_message_size,
+        compression_options: Optional[Dict[str, Any]] = None,
+    ) -> None:
+        self.ping_interval = ping_interval
+        self.ping_timeout = ping_timeout
+        self.max_message_size = max_message_size
+        self.compression_options = compression_options
+
+
+class WebSocketHandler(tornado.web.RequestHandler):
+    """Subclass this class to create a basic WebSocket handler.
+
+    Override `on_message` to handle incoming messages, and use
+    `write_message` to send messages to the client. You can also
+    override `open` and `on_close` to handle opened and closed
+    connections.
+
+    Custom upgrade response headers can be sent by overriding
+    `~tornado.web.RequestHandler.set_default_headers` or
+    `~tornado.web.RequestHandler.prepare`.
+
+    See http://dev.w3.org/html5/websockets/ for details on the
+    JavaScript interface.  The protocol is specified at
+    http://tools.ietf.org/html/rfc6455.
+
+    Here is an example WebSocket handler that echos back all received messages
+    back to the client:
+
+    .. testcode::
+
+      class EchoWebSocket(tornado.websocket.WebSocketHandler):
+          def open(self):
+              print("WebSocket opened")
+
+          def on_message(self, message):
+              self.write_message(u"You said: " + message)
+
+          def on_close(self):
+              print("WebSocket closed")
+
+    .. testoutput::
+       :hide:
+
+    WebSockets are not standard HTTP connections. The "handshake" is
+    HTTP, but after the handshake, the protocol is
+    message-based. Consequently, most of the Tornado HTTP facilities
+    are not available in handlers of this type. The only communication
+    methods available to you are `write_message()`, `ping()`, and
+    `close()`. Likewise, your request handler class should implement
+    `open()` method rather than ``get()`` or ``post()``.
+
+    If you map the handler above to ``/websocket`` in your application, you can
+    invoke it in JavaScript with::
+
+      var ws = new WebSocket("ws://localhost:8888/websocket");
+      ws.onopen = function() {
+         ws.send("Hello, world");
+      };
+      ws.onmessage = function (evt) {
+         alert(evt.data);
+      };
+
+    This script pops up an alert box that says "You said: Hello, world".
+
+    Web browsers allow any site to open a websocket connection to any other,
+    instead of using the same-origin policy that governs other network
+    access from JavaScript.  This can be surprising and is a potential
+    security hole, so since Tornado 4.0 `WebSocketHandler` requires
+    applications that wish to receive cross-origin websockets to opt in
+    by overriding the `~WebSocketHandler.check_origin` method (see that
+    method's docs for details).  Failure to do so is the most likely
+    cause of 403 errors when making a websocket connection.
+
+    When using a secure websocket connection (``wss://``) with a self-signed
+    certificate, the connection from a browser may fail because it wants
+    to show the "accept this certificate" dialog but has nowhere to show it.
+    You must first visit a regular HTML page using the same certificate
+    to accept it before the websocket connection will succeed.
+
+    If the application setting ``websocket_ping_interval`` has a non-zero
+    value, a ping will be sent periodically, and the connection will be
+    closed if a response is not received before the ``websocket_ping_timeout``.
+
+    Messages larger than the ``websocket_max_message_size`` application setting
+    (default 10MiB) will not be accepted.
+
+    .. versionchanged:: 4.5
+       Added ``websocket_ping_interval``, ``websocket_ping_timeout``, and
+       ``websocket_max_message_size``.
+    """
+
+    def __init__(
+        self,
+        application: tornado.web.Application,
+        request: httputil.HTTPServerRequest,
+        **kwargs: Any
+    ) -> None:
+        super().__init__(application, request, **kwargs)
+        self.ws_connection = None  # type: Optional[WebSocketProtocol]
+        self.close_code = None  # type: Optional[int]
+        self.close_reason = None  # type: Optional[str]
+        self._on_close_called = False
+
+    async def get(self, *args: Any, **kwargs: Any) -> None:
+        self.open_args = args
+        self.open_kwargs = kwargs
+
+        # Upgrade header should be present and should be equal to WebSocket
+        if self.request.headers.get("Upgrade", "").lower() != "websocket":
+            self.set_status(400)
+            log_msg = 'Can "Upgrade" only to "WebSocket".'
+            self.finish(log_msg)
+            gen_log.debug(log_msg)
+            return
+
+        # Connection header should be upgrade.
+        # Some proxy servers/load balancers
+        # might mess with it.
+        headers = self.request.headers
+        connection = map(
+            lambda s: s.strip().lower(), headers.get("Connection", "").split(",")
+        )
+        if "upgrade" not in connection:
+            self.set_status(400)
+            log_msg = '"Connection" must be "Upgrade".'
+            self.finish(log_msg)
+            gen_log.debug(log_msg)
+            return
+
+        # Handle WebSocket Origin naming convention differences
+        # The difference between version 8 and 13 is that in 8 the
+        # client sends a "Sec-Websocket-Origin" header and in 13 it's
+        # simply "Origin".
+        if "Origin" in self.request.headers:
+            origin = self.request.headers.get("Origin")
+        else:
+            origin = self.request.headers.get("Sec-Websocket-Origin", None)
+
+        # If there was an origin header, check to make sure it matches
+        # according to check_origin. When the origin is None, we assume it
+        # did not come from a browser and that it can be passed on.
+        if origin is not None and not self.check_origin(origin):
+            self.set_status(403)
+            log_msg = "Cross origin websockets not allowed"
+            self.finish(log_msg)
+            gen_log.debug(log_msg)
+            return
+
+        self.ws_connection = self.get_websocket_protocol()
+        if self.ws_connection:
+            await self.ws_connection.accept_connection(self)
+        else:
+            self.set_status(426, "Upgrade Required")
+            self.set_header("Sec-WebSocket-Version", "7, 8, 13")
+
+    @property
+    def ping_interval(self) -> Optional[float]:
+        """The interval for websocket keep-alive pings.
+
+        Set websocket_ping_interval = 0 to disable pings.
+        """
+        return self.settings.get("websocket_ping_interval", None)
+
+    @property
+    def ping_timeout(self) -> Optional[float]:
+        """If no ping is received in this many seconds,
+        close the websocket connection (VPNs, etc. can fail to cleanly close ws connections).
+        Default is max of 3 pings or 30 seconds.
+        """
+        return self.settings.get("websocket_ping_timeout", None)
+
+    @property
+    def max_message_size(self) -> int:
+        """Maximum allowed message size.
+
+        If the remote peer sends a message larger than this, the connection
+        will be closed.
+
+        Default is 10MiB.
+        """
+        return self.settings.get(
+            "websocket_max_message_size", _default_max_message_size
+        )
+
+    def write_message(
+        self, message: Union[bytes, str, Dict[str, Any]], binary: bool = False
+    ) -> "Future[None]":
+        """Sends the given message to the client of this Web Socket.
+
+        The message may be either a string or a dict (which will be
+        encoded as json).  If the ``binary`` argument is false, the
+        message will be sent as utf8; in binary mode any byte string
+        is allowed.
+
+        If the connection is already closed, raises `WebSocketClosedError`.
+        Returns a `.Future` which can be used for flow control.
+
+        .. versionchanged:: 3.2
+           `WebSocketClosedError` was added (previously a closed connection
+           would raise an `AttributeError`)
+
+        .. versionchanged:: 4.3
+           Returns a `.Future` which can be used for flow control.
+
+        .. versionchanged:: 5.0
+           Consistently raises `WebSocketClosedError`. Previously could
+           sometimes raise `.StreamClosedError`.
+        """
+        if self.ws_connection is None or self.ws_connection.is_closing():
+            raise WebSocketClosedError()
+        if isinstance(message, dict):
+            message = tornado.escape.json_encode(message)
+        return self.ws_connection.write_message(message, binary=binary)
+
+    def select_subprotocol(self, subprotocols: List[str]) -> Optional[str]:
+        """Override to implement subprotocol negotiation.
+
+        ``subprotocols`` is a list of strings identifying the
+        subprotocols proposed by the client.  This method may be
+        overridden to return one of those strings to select it, or
+        ``None`` to not select a subprotocol.
+
+        Failure to select a subprotocol does not automatically abort
+        the connection, although clients may close the connection if
+        none of their proposed subprotocols was selected.
+
+        The list may be empty, in which case this method must return
+        None. This method is always called exactly once even if no
+        subprotocols were proposed so that the handler can be advised
+        of this fact.
+
+        .. versionchanged:: 5.1
+
+           Previously, this method was called with a list containing
+           an empty string instead of an empty list if no subprotocols
+           were proposed by the client.
+        """
+        return None
+
+    @property
+    def selected_subprotocol(self) -> Optional[str]:
+        """The subprotocol returned by `select_subprotocol`.
+
+        .. versionadded:: 5.1
+        """
+        assert self.ws_connection is not None
+        return self.ws_connection.selected_subprotocol
+
+    def get_compression_options(self) -> Optional[Dict[str, Any]]:
+        """Override to return compression options for the connection.
+
+        If this method returns None (the default), compression will
+        be disabled.  If it returns a dict (even an empty one), it
+        will be enabled.  The contents of the dict may be used to
+        control the following compression options:
+
+        ``compression_level`` specifies the compression level.
+
+        ``mem_level`` specifies the amount of memory used for the internal compression state.
+
+         These parameters are documented in details here:
+         https://docs.python.org/3.6/library/zlib.html#zlib.compressobj
+
+        .. versionadded:: 4.1
+
+        .. versionchanged:: 4.5
+
+           Added ``compression_level`` and ``mem_level``.
+        """
+        # TODO: Add wbits option.
+        return None
+
+    def open(self, *args: str, **kwargs: str) -> Optional[Awaitable[None]]:
+        """Invoked when a new WebSocket is opened.
+
+        The arguments to `open` are extracted from the `tornado.web.URLSpec`
+        regular expression, just like the arguments to
+        `tornado.web.RequestHandler.get`.
+
+        `open` may be a coroutine. `on_message` will not be called until
+        `open` has returned.
+
+        .. versionchanged:: 5.1
+
+           ``open`` may be a coroutine.
+        """
+        pass
+
+    def on_message(self, message: Union[str, bytes]) -> Optional[Awaitable[None]]:
+        """Handle incoming messages on the WebSocket
+
+        This method must be overridden.
+
+        .. versionchanged:: 4.5
+
+           ``on_message`` can be a coroutine.
+        """
+        raise NotImplementedError
+
+    def ping(self, data: Union[str, bytes] = b"") -> None:
+        """Send ping frame to the remote end.
+
+        The data argument allows a small amount of data (up to 125
+        bytes) to be sent as a part of the ping message. Note that not
+        all websocket implementations expose this data to
+        applications.
+
+        Consider using the ``websocket_ping_interval`` application
+        setting instead of sending pings manually.
+
+        .. versionchanged:: 5.1
+
+           The data argument is now optional.
+
+        """
+        data = utf8(data)
+        if self.ws_connection is None or self.ws_connection.is_closing():
+            raise WebSocketClosedError()
+        self.ws_connection.write_ping(data)
+
+    def on_pong(self, data: bytes) -> None:
+        """Invoked when the response to a ping frame is received."""
+        pass
+
+    def on_ping(self, data: bytes) -> None:
+        """Invoked when the a ping frame is received."""
+        pass
+
+    def on_close(self) -> None:
+        """Invoked when the WebSocket is closed.
+
+        If the connection was closed cleanly and a status code or reason
+        phrase was supplied, these values will be available as the attributes
+        ``self.close_code`` and ``self.close_reason``.
+
+        .. versionchanged:: 4.0
+
+           Added ``close_code`` and ``close_reason`` attributes.
+        """
+        pass
+
+    def close(self, code: Optional[int] = None, reason: Optional[str] = None) -> None:
+        """Closes this Web Socket.
+
+        Once the close handshake is successful the socket will be closed.
+
+        ``code`` may be a numeric status code, taken from the values
+        defined in `RFC 6455 section 7.4.1
+        <https://tools.ietf.org/html/rfc6455#section-7.4.1>`_.
+        ``reason`` may be a textual message about why the connection is
+        closing.  These values are made available to the client, but are
+        not otherwise interpreted by the websocket protocol.
+
+        .. versionchanged:: 4.0
+
+           Added the ``code`` and ``reason`` arguments.
+        """
+        if self.ws_connection:
+            self.ws_connection.close(code, reason)
+            self.ws_connection = None
+
+    def check_origin(self, origin: str) -> bool:
+        """Override to enable support for allowing alternate origins.
+
+        The ``origin`` argument is the value of the ``Origin`` HTTP
+        header, the url responsible for initiating this request.  This
+        method is not called for clients that do not send this header;
+        such requests are always allowed (because all browsers that
+        implement WebSockets support this header, and non-browser
+        clients do not have the same cross-site security concerns).
+
+        Should return ``True`` to accept the request or ``False`` to
+        reject it. By default, rejects all requests with an origin on
+        a host other than this one.
+
+        This is a security protection against cross site scripting attacks on
+        browsers, since WebSockets are allowed to bypass the usual same-origin
+        policies and don't use CORS headers.
+
+        .. warning::
+
+           This is an important security measure; don't disable it
+           without understanding the security implications. In
+           particular, if your authentication is cookie-based, you
+           must either restrict the origins allowed by
+           ``check_origin()`` or implement your own XSRF-like
+           protection for websocket connections. See `these
+           <https://www.christian-schneider.net/CrossSiteWebSocketHijacking.html>`_
+           `articles
+           <https://devcenter.heroku.com/articles/websocket-security>`_
+           for more.
+
+        To accept all cross-origin traffic (which was the default prior to
+        Tornado 4.0), simply override this method to always return ``True``::
+
+            def check_origin(self, origin):
+                return True
+
+        To allow connections from any subdomain of your site, you might
+        do something like::
+
+            def check_origin(self, origin):
+                parsed_origin = urllib.parse.urlparse(origin)
+                return parsed_origin.netloc.endswith(".mydomain.com")
+
+        .. versionadded:: 4.0
+
+        """
+        parsed_origin = urlparse(origin)
+        origin = parsed_origin.netloc
+        origin = origin.lower()
+
+        host = self.request.headers.get("Host")
+
+        # Check to see that origin matches host directly, including ports
+        return origin == host
+
+    def set_nodelay(self, value: bool) -> None:
+        """Set the no-delay flag for this stream.
+
+        By default, small messages may be delayed and/or combined to minimize
+        the number of packets sent.  This can sometimes cause 200-500ms delays
+        due to the interaction between Nagle's algorithm and TCP delayed
+        ACKs.  To reduce this delay (at the expense of possibly increasing
+        bandwidth usage), call ``self.set_nodelay(True)`` once the websocket
+        connection is established.
+
+        See `.BaseIOStream.set_nodelay` for additional details.
+
+        .. versionadded:: 3.1
+        """
+        assert self.ws_connection is not None
+        self.ws_connection.set_nodelay(value)
+
+    def on_connection_close(self) -> None:
+        if self.ws_connection:
+            self.ws_connection.on_connection_close()
+            self.ws_connection = None
+        if not self._on_close_called:
+            self._on_close_called = True
+            self.on_close()
+            self._break_cycles()
+
+    def on_ws_connection_close(
+        self, close_code: Optional[int] = None, close_reason: Optional[str] = None
+    ) -> None:
+        self.close_code = close_code
+        self.close_reason = close_reason
+        self.on_connection_close()
+
+    def _break_cycles(self) -> None:
+        # WebSocketHandlers call finish() early, but we don't want to
+        # break up reference cycles (which makes it impossible to call
+        # self.render_string) until after we've really closed the
+        # connection (if it was established in the first place,
+        # indicated by status code 101).
+        if self.get_status() != 101 or self._on_close_called:
+            super()._break_cycles()
+
+    def get_websocket_protocol(self) -> Optional["WebSocketProtocol"]:
+        websocket_version = self.request.headers.get("Sec-WebSocket-Version")
+        if websocket_version in ("7", "8", "13"):
+            params = _WebSocketParams(
+                ping_interval=self.ping_interval,
+                ping_timeout=self.ping_timeout,
+                max_message_size=self.max_message_size,
+                compression_options=self.get_compression_options(),
+            )
+            return WebSocketProtocol13(self, False, params)
+        return None
+
+    def _detach_stream(self) -> IOStream:
+        # disable non-WS methods
+        for method in [
+            "write",
+            "redirect",
+            "set_header",
+            "set_cookie",
+            "set_status",
+            "flush",
+            "finish",
+        ]:
+            setattr(self, method, _raise_not_supported_for_websockets)
+        return self.detach()
+
+
+def _raise_not_supported_for_websockets(*args: Any, **kwargs: Any) -> None:
+    raise RuntimeError("Method not supported for Web Sockets")
+
+
+class WebSocketProtocol(abc.ABC):
+    """Base class for WebSocket protocol versions."""
+
+    def __init__(self, handler: "_WebSocketDelegate") -> None:
+        self.handler = handler
+        self.stream = None  # type: Optional[IOStream]
+        self.client_terminated = False
+        self.server_terminated = False
+
+    def _run_callback(
+        self, callback: Callable, *args: Any, **kwargs: Any
+    ) -> "Optional[Future[Any]]":
+        """Runs the given callback with exception handling.
+
+        If the callback is a coroutine, returns its Future. On error, aborts the
+        websocket connection and returns None.
+        """
+        try:
+            result = callback(*args, **kwargs)
+        except Exception:
+            self.handler.log_exception(*sys.exc_info())
+            self._abort()
+            return None
+        else:
+            if result is not None:
+                result = gen.convert_yielded(result)
+                assert self.stream is not None
+                self.stream.io_loop.add_future(result, lambda f: f.result())
+            return result
+
+    def on_connection_close(self) -> None:
+        self._abort()
+
+    def _abort(self) -> None:
+        """Instantly aborts the WebSocket connection by closing the socket"""
+        self.client_terminated = True
+        self.server_terminated = True
+        if self.stream is not None:
+            self.stream.close()  # forcibly tear down the connection
+        self.close()  # let the subclass cleanup
+
+    @abc.abstractmethod
+    def close(self, code: Optional[int] = None, reason: Optional[str] = None) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def is_closing(self) -> bool:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    async def accept_connection(self, handler: WebSocketHandler) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def write_message(
+        self, message: Union[str, bytes, Dict[str, Any]], binary: bool = False
+    ) -> "Future[None]":
+        raise NotImplementedError()
+
+    @property
+    @abc.abstractmethod
+    def selected_subprotocol(self) -> Optional[str]:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def write_ping(self, data: bytes) -> None:
+        raise NotImplementedError()
+
+    # The entry points below are used by WebSocketClientConnection,
+    # which was introduced after we only supported a single version of
+    # WebSocketProtocol. The WebSocketProtocol/WebSocketProtocol13
+    # boundary is currently pretty ad-hoc.
+    @abc.abstractmethod
+    def _process_server_headers(
+        self, key: Union[str, bytes], headers: httputil.HTTPHeaders
+    ) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def start_pinging(self) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    async def _receive_frame_loop(self) -> None:
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def set_nodelay(self, x: bool) -> None:
+        raise NotImplementedError()
+
+
+class _PerMessageDeflateCompressor(object):
+    def __init__(
+        self,
+        persistent: bool,
+        max_wbits: Optional[int],
+        compression_options: Optional[Dict[str, Any]] = None,
+    ) -> None:
+        if max_wbits is None:
+            max_wbits = zlib.MAX_WBITS
+        # There is no symbolic constant for the minimum wbits value.
+        if not (8 <= max_wbits <= zlib.MAX_WBITS):
+            raise ValueError(
+                "Invalid max_wbits value %r; allowed range 8-%d",
+                max_wbits,
+                zlib.MAX_WBITS,
+            )
+        self._max_wbits = max_wbits
+
+        if (
+            compression_options is None
+            or "compression_level" not in compression_options
+        ):
+            self._compression_level = tornado.web.GZipContentEncoding.GZIP_LEVEL
+        else:
+            self._compression_level = compression_options["compression_level"]
+
+        if compression_options is None or "mem_level" not in compression_options:
+            self._mem_level = 8
+        else:
+            self._mem_level = compression_options["mem_level"]
+
+        if persistent:
+            self._compressor = self._create_compressor()  # type: Optional[_Compressor]
+        else:
+            self._compressor = None
+
+    def _create_compressor(self) -> "_Compressor":
+        return zlib.compressobj(
+            self._compression_level, zlib.DEFLATED, -self._max_wbits, self._mem_level
+        )
+
+    def compress(self, data: bytes) -> bytes:
+        compressor = self._compressor or self._create_compressor()
+        data = compressor.compress(data) + compressor.flush(zlib.Z_SYNC_FLUSH)
+        assert data.endswith(b"\x00\x00\xff\xff")
+        return data[:-4]
+
+
+class _PerMessageDeflateDecompressor(object):
+    def __init__(
+        self,
+        persistent: bool,
+        max_wbits: Optional[int],
+        max_message_size: int,
+        compression_options: Optional[Dict[str, Any]] = None,
+    ) -> None:
+        self._max_message_size = max_message_size
+        if max_wbits is None:
+            max_wbits = zlib.MAX_WBITS
+        if not (8 <= max_wbits <= zlib.MAX_WBITS):
+            raise ValueError(
+                "Invalid max_wbits value %r; allowed range 8-%d",
+                max_wbits,
+                zlib.MAX_WBITS,
+            )
+        self._max_wbits = max_wbits
+        if persistent:
+            self._decompressor = (
+                self._create_decompressor()
+            )  # type: Optional[_Decompressor]
+        else:
+            self._decompressor = None
+
+    def _create_decompressor(self) -> "_Decompressor":
+        return zlib.decompressobj(-self._max_wbits)
+
+    def decompress(self, data: bytes) -> bytes:
+        decompressor = self._decompressor or self._create_decompressor()
+        result = decompressor.decompress(
+            data + b"\x00\x00\xff\xff", self._max_message_size
+        )
+        if decompressor.unconsumed_tail:
+            raise _DecompressTooLargeError()
+        return result
+
+
+class WebSocketProtocol13(WebSocketProtocol):
+    """Implementation of the WebSocket protocol from RFC 6455.
+
+    This class supports versions 7 and 8 of the protocol in addition to the
+    final version 13.
+    """
+
+    # Bit masks for the first byte of a frame.
+    FIN = 0x80
+    RSV1 = 0x40
+    RSV2 = 0x20
+    RSV3 = 0x10
+    RSV_MASK = RSV1 | RSV2 | RSV3
+    OPCODE_MASK = 0x0F
+
+    stream = None  # type: IOStream
+
+    def __init__(
+        self,
+        handler: "_WebSocketDelegate",
+        mask_outgoing: bool,
+        params: _WebSocketParams,
+    ) -> None:
+        WebSocketProtocol.__init__(self, handler)
+        self.mask_outgoing = mask_outgoing
+        self.params = params
+        self._final_frame = False
+        self._frame_opcode = None
+        self._masked_frame = None
+        self._frame_mask = None  # type: Optional[bytes]
+        self._frame_length = None
+        self._fragmented_message_buffer = None  # type: Optional[bytearray]
+        self._fragmented_message_opcode = None
+        self._waiting = None  # type: object
+        self._compression_options = params.compression_options
+        self._decompressor = None  # type: Optional[_PerMessageDeflateDecompressor]
+        self._compressor = None  # type: Optional[_PerMessageDeflateCompressor]
+        self._frame_compressed = None  # type: Optional[bool]
+        # The total uncompressed size of all messages received or sent.
+        # Unicode messages are encoded to utf8.
+        # Only for testing; subject to change.
+        self._message_bytes_in = 0
+        self._message_bytes_out = 0
+        # The total size of all packets received or sent.  Includes
+        # the effect of compression, frame overhead, and control frames.
+        self._wire_bytes_in = 0
+        self._wire_bytes_out = 0
+        self.ping_callback = None  # type: Optional[PeriodicCallback]
+        self.last_ping = 0.0
+        self.last_pong = 0.0
+        self.close_code = None  # type: Optional[int]
+        self.close_reason = None  # type: Optional[str]
+
+    # Use a property for this to satisfy the abc.
+    @property
+    def selected_subprotocol(self) -> Optional[str]:
+        return self._selected_subprotocol
+
+    @selected_subprotocol.setter
+    def selected_subprotocol(self, value: Optional[str]) -> None:
+        self._selected_subprotocol = value
+
+    async def accept_connection(self, handler: WebSocketHandler) -> None:
+        try:
+            self._handle_websocket_headers(handler)
+        except ValueError:
+            handler.set_status(400)
+            log_msg = "Missing/Invalid WebSocket headers"
+            handler.finish(log_msg)
+            gen_log.debug(log_msg)
+            return
+
+        try:
+            await self._accept_connection(handler)
+        except asyncio.CancelledError:
+            self._abort()
+            return
+        except ValueError:
+            gen_log.debug("Malformed WebSocket request received", exc_info=True)
+            self._abort()
+            return
+
+    def _handle_websocket_headers(self, handler: WebSocketHandler) -> None:
+        """Verifies all invariant- and required headers
+
+        If a header is missing or have an incorrect value ValueError will be
+        raised
+        """
+        fields = ("Host", "Sec-Websocket-Key", "Sec-Websocket-Version")
+        if not all(map(lambda f: handler.request.headers.get(f), fields)):
+            raise ValueError("Missing/Invalid WebSocket headers")
+
+    @staticmethod
+    def compute_accept_value(key: Union[str, bytes]) -> str:
+        """Computes the value for the Sec-WebSocket-Accept header,
+        given the value for Sec-WebSocket-Key.
+        """
+        sha1 = hashlib.sha1()
+        sha1.update(utf8(key))
+        sha1.update(b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11")  # Magic value
+        return native_str(base64.b64encode(sha1.digest()))
+
+    def _challenge_response(self, handler: WebSocketHandler) -> str:
+        return WebSocketProtocol13.compute_accept_value(
+            cast(str, handler.request.headers.get("Sec-Websocket-Key"))
+        )
+
+    async def _accept_connection(self, handler: WebSocketHandler) -> None:
+        subprotocol_header = handler.request.headers.get("Sec-WebSocket-Protocol")
+        if subprotocol_header:
+            subprotocols = [s.strip() for s in subprotocol_header.split(",")]
+        else:
+            subprotocols = []
+        self.selected_subprotocol = handler.select_subprotocol(subprotocols)
+        if self.selected_subprotocol:
+            assert self.selected_subprotocol in subprotocols
+            handler.set_header("Sec-WebSocket-Protocol", self.selected_subprotocol)
+
+        extensions = self._parse_extensions_header(handler.request.headers)
+        for ext in extensions:
+            if ext[0] == "permessage-deflate" and self._compression_options is not None:
+                # TODO: negotiate parameters if compression_options
+                # specifies limits.
+                self._create_compressors("server", ext[1], self._compression_options)
+                if (
+                    "client_max_window_bits" in ext[1]
+                    and ext[1]["client_max_window_bits"] is None
+                ):
+                    # Don't echo an offered client_max_window_bits
+                    # parameter with no value.
+                    del ext[1]["client_max_window_bits"]
+                handler.set_header(
+                    "Sec-WebSocket-Extensions",
+                    httputil._encode_header("permessage-deflate", ext[1]),
+                )
+                break
+
+        handler.clear_header("Content-Type")
+        handler.set_status(101)
+        handler.set_header("Upgrade", "websocket")
+        handler.set_header("Connection", "Upgrade")
+        handler.set_header("Sec-WebSocket-Accept", self._challenge_response(handler))
+        handler.finish()
+
+        self.stream = handler._detach_stream()
+
+        self.start_pinging()
+        try:
+            open_result = handler.open(*handler.open_args, **handler.open_kwargs)
+            if open_result is not None:
+                await open_result
+        except Exception:
+            handler.log_exception(*sys.exc_info())
+            self._abort()
+            return
+
+        await self._receive_frame_loop()
+
+    def _parse_extensions_header(
+        self, headers: httputil.HTTPHeaders
+    ) -> List[Tuple[str, Dict[str, str]]]:
+        extensions = headers.get("Sec-WebSocket-Extensions", "")
+        if extensions:
+            return [httputil._parse_header(e.strip()) for e in extensions.split(",")]
+        return []
+
+    def _process_server_headers(
+        self, key: Union[str, bytes], headers: httputil.HTTPHeaders
+    ) -> None:
+        """Process the headers sent by the server to this client connection.
+
+        'key' is the websocket handshake challenge/response key.
+        """
+        assert headers["Upgrade"].lower() == "websocket"
+        assert headers["Connection"].lower() == "upgrade"
+        accept = self.compute_accept_value(key)
+        assert headers["Sec-Websocket-Accept"] == accept
+
+        extensions = self._parse_extensions_header(headers)
+        for ext in extensions:
+            if ext[0] == "permessage-deflate" and self._compression_options is not None:
+                self._create_compressors("client", ext[1])
+            else:
+                raise ValueError("unsupported extension %r", ext)
+
+        self.selected_subprotocol = headers.get("Sec-WebSocket-Protocol", None)
+
+    def _get_compressor_options(
+        self,
+        side: str,
+        agreed_parameters: Dict[str, Any],
+        compression_options: Optional[Dict[str, Any]] = None,
+    ) -> Dict[str, Any]:
+        """Converts a websocket agreed_parameters set to keyword arguments
+        for our compressor objects.
+        """
+        options = dict(
+            persistent=(side + "_no_context_takeover") not in agreed_parameters
+        )  # type: Dict[str, Any]
+        wbits_header = agreed_parameters.get(side + "_max_window_bits", None)
+        if wbits_header is None:
+            options["max_wbits"] = zlib.MAX_WBITS
+        else:
+            options["max_wbits"] = int(wbits_header)
+        options["compression_options"] = compression_options
+        return options
+
+    def _create_compressors(
+        self,
+        side: str,
+        agreed_parameters: Dict[str, Any],
+        compression_options: Optional[Dict[str, Any]] = None,
+    ) -> None:
+        # TODO: handle invalid parameters gracefully
+        allowed_keys = set(
+            [
+                "server_no_context_takeover",
+                "client_no_context_takeover",
+                "server_max_window_bits",
+                "client_max_window_bits",
+            ]
+        )
+        for key in agreed_parameters:
+            if key not in allowed_keys:
+                raise ValueError("unsupported compression parameter %r" % key)
+        other_side = "client" if (side == "server") else "server"
+        self._compressor = _PerMessageDeflateCompressor(
+            **self._get_compressor_options(side, agreed_parameters, compression_options)
+        )
+        self._decompressor = _PerMessageDeflateDecompressor(
+            max_message_size=self.params.max_message_size,
+            **self._get_compressor_options(
+                other_side, agreed_parameters, compression_options
+            )
+        )
+
+    def _write_frame(
+        self, fin: bool, opcode: int, data: bytes, flags: int = 0
+    ) -> "Future[None]":
+        data_len = len(data)
+        if opcode & 0x8:
+            # All control frames MUST have a payload length of 125
+            # bytes or less and MUST NOT be fragmented.
+            if not fin:
+                raise ValueError("control frames may not be fragmented")
+            if data_len > 125:
+                raise ValueError("control frame payloads may not exceed 125 bytes")
+        if fin:
+            finbit = self.FIN
+        else:
+            finbit = 0
+        frame = struct.pack("B", finbit | opcode | flags)
+        if self.mask_outgoing:
+            mask_bit = 0x80
+        else:
+            mask_bit = 0
+        if data_len < 126:
+            frame += struct.pack("B", data_len | mask_bit)
+        elif data_len <= 0xFFFF:
+            frame += struct.pack("!BH", 126 | mask_bit, data_len)
+        else:
+            frame += struct.pack("!BQ", 127 | mask_bit, data_len)
+        if self.mask_outgoing:
+            mask = os.urandom(4)
+            data = mask + _websocket_mask(mask, data)
+        frame += data
+        self._wire_bytes_out += len(frame)
+        return self.stream.write(frame)
+
+    def write_message(
+        self, message: Union[str, bytes, Dict[str, Any]], binary: bool = False
+    ) -> "Future[None]":
+        """Sends the given message to the client of this Web Socket."""
+        if binary:
+            opcode = 0x2
+        else:
+            opcode = 0x1
+        if isinstance(message, dict):
+            message = tornado.escape.json_encode(message)
+        message = tornado.escape.utf8(message)
+        assert isinstance(message, bytes)
+        self._message_bytes_out += len(message)
+        flags = 0
+        if self._compressor:
+            message = self._compressor.compress(message)
+            flags |= self.RSV1
+        # For historical reasons, write methods in Tornado operate in a semi-synchronous
+        # mode in which awaiting the Future they return is optional (But errors can
+        # still be raised). This requires us to go through an awkward dance here
+        # to transform the errors that may be returned while presenting the same
+        # semi-synchronous interface.
+        try:
+            fut = self._write_frame(True, opcode, message, flags=flags)
+        except StreamClosedError:
+            raise WebSocketClosedError()
+
+        async def wrapper() -> None:
+            try:
+                await fut
+            except StreamClosedError:
+                raise WebSocketClosedError()
+
+        return asyncio.ensure_future(wrapper())
+
+    def write_ping(self, data: bytes) -> None:
+        """Send ping frame."""
+        assert isinstance(data, bytes)
+        self._write_frame(True, 0x9, data)
+
+    async def _receive_frame_loop(self) -> None:
+        try:
+            while not self.client_terminated:
+                await self._receive_frame()
+        except StreamClosedError:
+            self._abort()
+        self.handler.on_ws_connection_close(self.close_code, self.close_reason)
+
+    async def _read_bytes(self, n: int) -> bytes:
+        data = await self.stream.read_bytes(n)
+        self._wire_bytes_in += n
+        return data
+
+    async def _receive_frame(self) -> None:
+        # Read the frame header.
+        data = await self._read_bytes(2)
+        header, mask_payloadlen = struct.unpack("BB", data)
+        is_final_frame = header & self.FIN
+        reserved_bits = header & self.RSV_MASK
+        opcode = header & self.OPCODE_MASK
+        opcode_is_control = opcode & 0x8
+        if self._decompressor is not None and opcode != 0:
+            # Compression flag is present in the first frame's header,
+            # but we can't decompress until we have all the frames of
+            # the message.
+            self._frame_compressed = bool(reserved_bits & self.RSV1)
+            reserved_bits &= ~self.RSV1
+        if reserved_bits:
+            # client is using as-yet-undefined extensions; abort
+            self._abort()
+            return
+        is_masked = bool(mask_payloadlen & 0x80)
+        payloadlen = mask_payloadlen & 0x7F
+
+        # Parse and validate the length.
+        if opcode_is_control and payloadlen >= 126:
+            # control frames must have payload < 126
+            self._abort()
+            return
+        if payloadlen < 126:
+            self._frame_length = payloadlen
+        elif payloadlen == 126:
+            data = await self._read_bytes(2)
+            payloadlen = struct.unpack("!H", data)[0]
+        elif payloadlen == 127:
+            data = await self._read_bytes(8)
+            payloadlen = struct.unpack("!Q", data)[0]
+        new_len = payloadlen
+        if self._fragmented_message_buffer is not None:
+            new_len += len(self._fragmented_message_buffer)
+        if new_len > self.params.max_message_size:
+            self.close(1009, "message too big")
+            self._abort()
+            return
+
+        # Read the payload, unmasking if necessary.
+        if is_masked:
+            self._frame_mask = await self._read_bytes(4)
+        data = await self._read_bytes(payloadlen)
+        if is_masked:
+            assert self._frame_mask is not None
+            data = _websocket_mask(self._frame_mask, data)
+
+        # Decide what to do with this frame.
+        if opcode_is_control:
+            # control frames may be interleaved with a series of fragmented
+            # data frames, so control frames must not interact with
+            # self._fragmented_*
+            if not is_final_frame:
+                # control frames must not be fragmented
+                self._abort()
+                return
+        elif opcode == 0:  # continuation frame
+            if self._fragmented_message_buffer is None:
+                # nothing to continue
+                self._abort()
+                return
+            self._fragmented_message_buffer.extend(data)
+            if is_final_frame:
+                opcode = self._fragmented_message_opcode
+                data = bytes(self._fragmented_message_buffer)
+                self._fragmented_message_buffer = None
+        else:  # start of new data message
+            if self._fragmented_message_buffer is not None:
+                # can't start new message until the old one is finished
+                self._abort()
+                return
+            if not is_final_frame:
+                self._fragmented_message_opcode = opcode
+                self._fragmented_message_buffer = bytearray(data)
+
+        if is_final_frame:
+            handled_future = self._handle_message(opcode, data)
+            if handled_future is not None:
+                await handled_future
+
+    def _handle_message(self, opcode: int, data: bytes) -> "Optional[Future[None]]":
+        """Execute on_message, returning its Future if it is a coroutine."""
+        if self.client_terminated:
+            return None
+
+        if self._frame_compressed:
+            assert self._decompressor is not None
+            try:
+                data = self._decompressor.decompress(data)
+            except _DecompressTooLargeError:
+                self.close(1009, "message too big after decompression")
+                self._abort()
+                return None
+
+        if opcode == 0x1:
+            # UTF-8 data
+            self._message_bytes_in += len(data)
+            try:
+                decoded = data.decode("utf-8")
+            except UnicodeDecodeError:
+                self._abort()
+                return None
+            return self._run_callback(self.handler.on_message, decoded)
+        elif opcode == 0x2:
+            # Binary data
+            self._message_bytes_in += len(data)
+            return self._run_callback(self.handler.on_message, data)
+        elif opcode == 0x8:
+            # Close
+            self.client_terminated = True
+            if len(data) >= 2:
+                self.close_code = struct.unpack(">H", data[:2])[0]
+            if len(data) > 2:
+                self.close_reason = to_unicode(data[2:])
+            # Echo the received close code, if any (RFC 6455 section 5.5.1).
+            self.close(self.close_code)
+        elif opcode == 0x9:
+            # Ping
+            try:
+                self._write_frame(True, 0xA, data)
+            except StreamClosedError:
+                self._abort()
+            self._run_callback(self.handler.on_ping, data)
+        elif opcode == 0xA:
+            # Pong
+            self.last_pong = IOLoop.current().time()
+            return self._run_callback(self.handler.on_pong, data)
+        else:
+            self._abort()
+        return None
+
+    def close(self, code: Optional[int] = None, reason: Optional[str] = None) -> None:
+        """Closes the WebSocket connection."""
+        if not self.server_terminated:
+            if not self.stream.closed():
+                if code is None and reason is not None:
+                    code = 1000  # "normal closure" status code
+                if code is None:
+                    close_data = b""
+                else:
+                    close_data = struct.pack(">H", code)
+                if reason is not None:
+                    close_data += utf8(reason)
+                try:
+                    self._write_frame(True, 0x8, close_data)
+                except StreamClosedError:
+                    self._abort()
+            self.server_terminated = True
+        if self.client_terminated:
+            if self._waiting is not None:
+                self.stream.io_loop.remove_timeout(self._waiting)
+                self._waiting = None
+            self.stream.close()
+        elif self._waiting is None:
+            # Give the client a few seconds to complete a clean shutdown,
+            # otherwise just close the connection.
+            self._waiting = self.stream.io_loop.add_timeout(
+                self.stream.io_loop.time() + 5, self._abort
+            )
+        if self.ping_callback:
+            self.ping_callback.stop()
+            self.ping_callback = None
+
+    def is_closing(self) -> bool:
+        """Return ``True`` if this connection is closing.
+
+        The connection is considered closing if either side has
+        initiated its closing handshake or if the stream has been
+        shut down uncleanly.
+        """
+        return self.stream.closed() or self.client_terminated or self.server_terminated
+
+    @property
+    def ping_interval(self) -> Optional[float]:
+        interval = self.params.ping_interval
+        if interval is not None:
+            return interval
+        return 0
+
+    @property
+    def ping_timeout(self) -> Optional[float]:
+        timeout = self.params.ping_timeout
+        if timeout is not None:
+            return timeout
+        assert self.ping_interval is not None
+        return max(3 * self.ping_interval, 30)
+
+    def start_pinging(self) -> None:
+        """Start sending periodic pings to keep the connection alive"""
+        assert self.ping_interval is not None
+        if self.ping_interval > 0:
+            self.last_ping = self.last_pong = IOLoop.current().time()
+            self.ping_callback = PeriodicCallback(
+                self.periodic_ping, self.ping_interval * 1000
+            )
+            self.ping_callback.start()
+
+    def periodic_ping(self) -> None:
+        """Send a ping to keep the websocket alive
+
+        Called periodically if the websocket_ping_interval is set and non-zero.
+        """
+        if self.is_closing() and self.ping_callback is not None:
+            self.ping_callback.stop()
+            return
+
+        # Check for timeout on pong. Make sure that we really have
+        # sent a recent ping in case the machine with both server and
+        # client has been suspended since the last ping.
+        now = IOLoop.current().time()
+        since_last_pong = now - self.last_pong
+        since_last_ping = now - self.last_ping
+        assert self.ping_interval is not None
+        assert self.ping_timeout is not None
+        if (
+            since_last_ping < 2 * self.ping_interval
+            and since_last_pong > self.ping_timeout
+        ):
+            self.close()
+            return
+
+        self.write_ping(b"")
+        self.last_ping = now
+
+    def set_nodelay(self, x: bool) -> None:
+        self.stream.set_nodelay(x)
+
+
+class WebSocketClientConnection(simple_httpclient._HTTPConnection):
+    """WebSocket client connection.
+
+    This class should not be instantiated directly; use the
+    `websocket_connect` function instead.
+    """
+
+    protocol = None  # type: WebSocketProtocol
+
+    def __init__(
+        self,
+        request: httpclient.HTTPRequest,
+        on_message_callback: Optional[Callable[[Union[None, str, bytes]], None]] = None,
+        compression_options: Optional[Dict[str, Any]] = None,
+        ping_interval: Optional[float] = None,
+        ping_timeout: Optional[float] = None,
+        max_message_size: int = _default_max_message_size,
+        subprotocols: Optional[List[str]] = [],
+        resolver: Optional[Resolver] = None,
+    ) -> None:
+        self.connect_future = Future()  # type: Future[WebSocketClientConnection]
+        self.read_queue = Queue(1)  # type: Queue[Union[None, str, bytes]]
+        self.key = base64.b64encode(os.urandom(16))
+        self._on_message_callback = on_message_callback
+        self.close_code = None  # type: Optional[int]
+        self.close_reason = None  # type: Optional[str]
+        self.params = _WebSocketParams(
+            ping_interval=ping_interval,
+            ping_timeout=ping_timeout,
+            max_message_size=max_message_size,
+            compression_options=compression_options,
+        )
+
+        scheme, sep, rest = request.url.partition(":")
+        scheme = {"ws": "http", "wss": "https"}[scheme]
+        request.url = scheme + sep + rest
+        request.headers.update(
+            {
+                "Upgrade": "websocket",
+                "Connection": "Upgrade",
+                "Sec-WebSocket-Key": self.key,
+                "Sec-WebSocket-Version": "13",
+            }
+        )
+        if subprotocols is not None:
+            request.headers["Sec-WebSocket-Protocol"] = ",".join(subprotocols)
+        if compression_options is not None:
+            # Always offer to let the server set our max_wbits (and even though
+            # we don't offer it, we will accept a client_no_context_takeover
+            # from the server).
+            # TODO: set server parameters for deflate extension
+            # if requested in self.compression_options.
+            request.headers[
+                "Sec-WebSocket-Extensions"
+            ] = "permessage-deflate; client_max_window_bits"
+
+        # Websocket connection is currently unable to follow redirects
+        request.follow_redirects = False
+
+        self.tcp_client = TCPClient(resolver=resolver)
+        super().__init__(
+            None,
+            request,
+            lambda: None,
+            self._on_http_response,
+            104857600,
+            self.tcp_client,
+            65536,
+            104857600,
+        )
+
+    def close(self, code: Optional[int] = None, reason: Optional[str] = None) -> None:
+        """Closes the websocket connection.
+
+        ``code`` and ``reason`` are documented under
+        `WebSocketHandler.close`.
+
+        .. versionadded:: 3.2
+
+        .. versionchanged:: 4.0
+
+           Added the ``code`` and ``reason`` arguments.
+        """
+        if self.protocol is not None:
+            self.protocol.close(code, reason)
+            self.protocol = None  # type: ignore
+
+    def on_connection_close(self) -> None:
+        if not self.connect_future.done():
+            self.connect_future.set_exception(StreamClosedError())
+        self._on_message(None)
+        self.tcp_client.close()
+        super().on_connection_close()
+
+    def on_ws_connection_close(
+        self, close_code: Optional[int] = None, close_reason: Optional[str] = None
+    ) -> None:
+        self.close_code = close_code
+        self.close_reason = close_reason
+        self.on_connection_close()
+
+    def _on_http_response(self, response: httpclient.HTTPResponse) -> None:
+        if not self.connect_future.done():
+            if response.error:
+                self.connect_future.set_exception(response.error)
+            else:
+                self.connect_future.set_exception(
+                    WebSocketError("Non-websocket response")
+                )
+
+    async def headers_received(
+        self,
+        start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
+        headers: httputil.HTTPHeaders,
+    ) -> None:
+        assert isinstance(start_line, httputil.ResponseStartLine)
+        if start_line.code != 101:
+            await super().headers_received(start_line, headers)
+            return
+
+        if self._timeout is not None:
+            self.io_loop.remove_timeout(self._timeout)
+            self._timeout = None
+
+        self.headers = headers
+        self.protocol = self.get_websocket_protocol()
+        self.protocol._process_server_headers(self.key, self.headers)
+        self.protocol.stream = self.connection.detach()
+
+        IOLoop.current().add_callback(self.protocol._receive_frame_loop)
+        self.protocol.start_pinging()
+
+        # Once we've taken over the connection, clear the final callback
+        # we set on the http request.  This deactivates the error handling
+        # in simple_httpclient that would otherwise interfere with our
+        # ability to see exceptions.
+        self.final_callback = None  # type: ignore
+
+        future_set_result_unless_cancelled(self.connect_future, self)
+
+    def write_message(
+        self, message: Union[str, bytes, Dict[str, Any]], binary: bool = False
+    ) -> "Future[None]":
+        """Sends a message to the WebSocket server.
+
+        If the stream is closed, raises `WebSocketClosedError`.
+        Returns a `.Future` which can be used for flow control.
+
+        .. versionchanged:: 5.0
+           Exception raised on a closed stream changed from `.StreamClosedError`
+           to `WebSocketClosedError`.
+        """
+        if self.protocol is None:
+            raise WebSocketClosedError("Client connection has been closed")
+        return self.protocol.write_message(message, binary=binary)
+
+    def read_message(
+        self,
+        callback: Optional[Callable[["Future[Union[None, str, bytes]]"], None]] = None,
+    ) -> Awaitable[Union[None, str, bytes]]:
+        """Reads a message from the WebSocket server.
+
+        If on_message_callback was specified at WebSocket
+        initialization, this function will never return messages
+
+        Returns a future whose result is the message, or None
+        if the connection is closed.  If a callback argument
+        is given it will be called with the future when it is
+        ready.
+        """
+
+        awaitable = self.read_queue.get()
+        if callback is not None:
+            self.io_loop.add_future(asyncio.ensure_future(awaitable), callback)
+        return awaitable
+
+    def on_message(self, message: Union[str, bytes]) -> Optional[Awaitable[None]]:
+        return self._on_message(message)
+
+    def _on_message(
+        self, message: Union[None, str, bytes]
+    ) -> Optional[Awaitable[None]]:
+        if self._on_message_callback:
+            self._on_message_callback(message)
+            return None
+        else:
+            return self.read_queue.put(message)
+
+    def ping(self, data: bytes = b"") -> None:
+        """Send ping frame to the remote end.
+
+        The data argument allows a small amount of data (up to 125
+        bytes) to be sent as a part of the ping message. Note that not
+        all websocket implementations expose this data to
+        applications.
+
+        Consider using the ``ping_interval`` argument to
+        `websocket_connect` instead of sending pings manually.
+
+        .. versionadded:: 5.1
+
+        """
+        data = utf8(data)
+        if self.protocol is None:
+            raise WebSocketClosedError()
+        self.protocol.write_ping(data)
+
+    def on_pong(self, data: bytes) -> None:
+        pass
+
+    def on_ping(self, data: bytes) -> None:
+        pass
+
+    def get_websocket_protocol(self) -> WebSocketProtocol:
+        return WebSocketProtocol13(self, mask_outgoing=True, params=self.params)
+
+    @property
+    def selected_subprotocol(self) -> Optional[str]:
+        """The subprotocol selected by the server.
+
+        .. versionadded:: 5.1
+        """
+        return self.protocol.selected_subprotocol
+
+    def log_exception(
+        self,
+        typ: "Optional[Type[BaseException]]",
+        value: Optional[BaseException],
+        tb: Optional[TracebackType],
+    ) -> None:
+        assert typ is not None
+        assert value is not None
+        app_log.error("Uncaught exception %s", value, exc_info=(typ, value, tb))
+
+
+def websocket_connect(
+    url: Union[str, httpclient.HTTPRequest],
+    callback: Optional[Callable[["Future[WebSocketClientConnection]"], None]] = None,
+    connect_timeout: Optional[float] = None,
+    on_message_callback: Optional[Callable[[Union[None, str, bytes]], None]] = None,
+    compression_options: Optional[Dict[str, Any]] = None,
+    ping_interval: Optional[float] = None,
+    ping_timeout: Optional[float] = None,
+    max_message_size: int = _default_max_message_size,
+    subprotocols: Optional[List[str]] = None,
+    resolver: Optional[Resolver] = None,
+) -> "Awaitable[WebSocketClientConnection]":
+    """Client-side websocket support.
+
+    Takes a url and returns a Future whose result is a
+    `WebSocketClientConnection`.
+
+    ``compression_options`` is interpreted in the same way as the
+    return value of `.WebSocketHandler.get_compression_options`.
+
+    The connection supports two styles of operation. In the coroutine
+    style, the application typically calls
+    `~.WebSocketClientConnection.read_message` in a loop::
+
+        conn = yield websocket_connect(url)
+        while True:
+            msg = yield conn.read_message()
+            if msg is None: break
+            # Do something with msg
+
+    In the callback style, pass an ``on_message_callback`` to
+    ``websocket_connect``. In both styles, a message of ``None``
+    indicates that the connection has been closed.
+
+    ``subprotocols`` may be a list of strings specifying proposed
+    subprotocols. The selected protocol may be found on the
+    ``selected_subprotocol`` attribute of the connection object
+    when the connection is complete.
+
+    .. versionchanged:: 3.2
+       Also accepts ``HTTPRequest`` objects in place of urls.
+
+    .. versionchanged:: 4.1
+       Added ``compression_options`` and ``on_message_callback``.
+
+    .. versionchanged:: 4.5
+       Added the ``ping_interval``, ``ping_timeout``, and ``max_message_size``
+       arguments, which have the same meaning as in `WebSocketHandler`.
+
+    .. versionchanged:: 5.0
+       The ``io_loop`` argument (deprecated since version 4.1) has been removed.
+
+    .. versionchanged:: 5.1
+       Added the ``subprotocols`` argument.
+
+    .. versionchanged:: 6.3
+       Added the ``resolver`` argument.
+    """
+    if isinstance(url, httpclient.HTTPRequest):
+        assert connect_timeout is None
+        request = url
+        # Copy and convert the headers dict/object (see comments in
+        # AsyncHTTPClient.fetch)
+        request.headers = httputil.HTTPHeaders(request.headers)
+    else:
+        request = httpclient.HTTPRequest(url, connect_timeout=connect_timeout)
+    request = cast(
+        httpclient.HTTPRequest,
+        httpclient._RequestProxy(request, httpclient.HTTPRequest._DEFAULTS),
+    )
+    conn = WebSocketClientConnection(
+        request,
+        on_message_callback=on_message_callback,
+        compression_options=compression_options,
+        ping_interval=ping_interval,
+        ping_timeout=ping_timeout,
+        max_message_size=max_message_size,
+        subprotocols=subprotocols,
+        resolver=resolver,
+    )
+    if callback is not None:
+        IOLoop.current().add_future(conn.connect_future, callback)
+    return conn.connect_future
diff --git a/venv/lib/python3.9/site-packages/tornado/wsgi.py b/venv/lib/python3.9/site-packages/tornado/wsgi.py
new file mode 100644
index 00000000..32641be3
--- /dev/null
+++ b/venv/lib/python3.9/site-packages/tornado/wsgi.py
@@ -0,0 +1,268 @@
+#
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""WSGI support for the Tornado web framework.
+
+WSGI is the Python standard for web servers, and allows for interoperability
+between Tornado and other Python web frameworks and servers.
+
+This module provides WSGI support via the `WSGIContainer` class, which
+makes it possible to run applications using other WSGI frameworks on
+the Tornado HTTP server. The reverse is not supported; the Tornado
+`.Application` and `.RequestHandler` classes are designed for use with
+the Tornado `.HTTPServer` and cannot be used in a generic WSGI
+container.
+
+"""
+
+import concurrent.futures
+from io import BytesIO
+import tornado
+import sys
+
+from tornado.concurrent import dummy_executor
+from tornado import escape
+from tornado import httputil
+from tornado.ioloop import IOLoop
+from tornado.log import access_log
+
+from typing import List, Tuple, Optional, Callable, Any, Dict, Text
+from types import TracebackType
+import typing
+
+if typing.TYPE_CHECKING:
+    from typing import Type  # noqa: F401
+    from _typeshed.wsgi import WSGIApplication as WSGIAppType  # noqa: F401
+
+
+# PEP 3333 specifies that WSGI on python 3 generally deals with byte strings
+# that are smuggled inside objects of type unicode (via the latin1 encoding).
+# This function is like those in the tornado.escape module, but defined
+# here to minimize the temptation to use it in non-wsgi contexts.
+def to_wsgi_str(s: bytes) -> str:
+    assert isinstance(s, bytes)
+    return s.decode("latin1")
+
+
+class WSGIContainer(object):
+    r"""Makes a WSGI-compatible application runnable on Tornado's HTTP server.
+
+    .. warning::
+
+       WSGI is a *synchronous* interface, while Tornado's concurrency model
+       is based on single-threaded *asynchronous* execution.  Many of Tornado's
+       distinguishing features are not available in WSGI mode, including efficient
+       long-polling and websockets. The primary purpose of `WSGIContainer` is
+       to support both WSGI applications and native Tornado ``RequestHandlers`` in
+       a single process. WSGI-only applications are likely to be better off
+       with a dedicated WSGI server such as ``gunicorn`` or ``uwsgi``.
+
+    Wrap a WSGI application in a `WSGIContainer` to make it implement the Tornado
+    `.HTTPServer` ``request_callback`` interface.  The `WSGIContainer` object can
+    then be passed to classes from the `tornado.routing` module,
+    `tornado.web.FallbackHandler`, or to `.HTTPServer` directly.
+
+    This class is intended to let other frameworks (Django, Flask, etc)
+    run on the Tornado HTTP server and I/O loop.
+
+    Realistic usage will be more complicated, but the simplest possible example uses a
+    hand-written WSGI application with `.HTTPServer`::
+
+        def simple_app(environ, start_response):
+            status = "200 OK"
+            response_headers = [("Content-type", "text/plain")]
+            start_response(status, response_headers)
+            return [b"Hello world!\n"]
+
+        async def main():
+            container = tornado.wsgi.WSGIContainer(simple_app)
+            http_server = tornado.httpserver.HTTPServer(container)
+            http_server.listen(8888)
+            await asyncio.Event().wait()
+
+        asyncio.run(main())
+
+    The recommended pattern is to use the `tornado.routing` module to set up routing
+    rules between your WSGI application and, typically, a `tornado.web.Application`.
+    Alternatively, `tornado.web.Application` can be used as the top-level router
+    and `tornado.web.FallbackHandler` can embed a `WSGIContainer` within it.
+
+    If the ``executor`` argument is provided, the WSGI application will be executed
+    on that executor. This must be an instance of `concurrent.futures.Executor`,
+    typically a ``ThreadPoolExecutor`` (``ProcessPoolExecutor`` is not supported).
+    If no ``executor`` is given, the application will run on the event loop thread in
+    Tornado 6.3; this will change to use an internal thread pool by default in
+    Tornado 7.0.
+
+    .. warning::
+       By default, the WSGI application is executed on the event loop's thread. This
+       limits the server to one request at a time (per process), making it less scalable
+       than most other WSGI servers. It is therefore highly recommended that you pass
+       a ``ThreadPoolExecutor`` when constructing the `WSGIContainer`, after verifying
+       that your application is thread-safe. The default will change to use a
+       ``ThreadPoolExecutor`` in Tornado 7.0.
+
+    .. versionadded:: 6.3
+       The ``executor`` parameter.
+
+    .. deprecated:: 6.3
+       The default behavior of running the WSGI application on the event loop thread
+       is deprecated and will change in Tornado 7.0 to use a thread pool by default.
+    """
+
+    def __init__(
+        self,
+        wsgi_application: "WSGIAppType",
+        executor: Optional[concurrent.futures.Executor] = None,
+    ) -> None:
+        self.wsgi_application = wsgi_application
+        self.executor = dummy_executor if executor is None else executor
+
+    def __call__(self, request: httputil.HTTPServerRequest) -> None:
+        IOLoop.current().spawn_callback(self.handle_request, request)
+
+    async def handle_request(self, request: httputil.HTTPServerRequest) -> None:
+        data = {}  # type: Dict[str, Any]
+        response = []  # type: List[bytes]
+
+        def start_response(
+            status: str,
+            headers: List[Tuple[str, str]],
+            exc_info: Optional[
+                Tuple[
+                    "Optional[Type[BaseException]]",
+                    Optional[BaseException],
+                    Optional[TracebackType],
+                ]
+            ] = None,
+        ) -> Callable[[bytes], Any]:
+            data["status"] = status
+            data["headers"] = headers
+            return response.append
+
+        loop = IOLoop.current()
+        app_response = await loop.run_in_executor(
+            self.executor,
+            self.wsgi_application,
+            self.environ(request),
+            start_response,
+        )
+        try:
+            app_response_iter = iter(app_response)
+
+            def next_chunk() -> Optional[bytes]:
+                try:
+                    return next(app_response_iter)
+                except StopIteration:
+                    # StopIteration is special and is not allowed to pass through
+                    # coroutines normally.
+                    return None
+
+            while True:
+                chunk = await loop.run_in_executor(self.executor, next_chunk)
+                if chunk is None:
+                    break
+                response.append(chunk)
+        finally:
+            if hasattr(app_response, "close"):
+                app_response.close()  # type: ignore
+        body = b"".join(response)
+        if not data:
+            raise Exception("WSGI app did not call start_response")
+
+        status_code_str, reason = data["status"].split(" ", 1)
+        status_code = int(status_code_str)
+        headers = data["headers"]  # type: List[Tuple[str, str]]
+        header_set = set(k.lower() for (k, v) in headers)
+        body = escape.utf8(body)
+        if status_code != 304:
+            if "content-length" not in header_set:
+                headers.append(("Content-Length", str(len(body))))
+            if "content-type" not in header_set:
+                headers.append(("Content-Type", "text/html; charset=UTF-8"))
+        if "server" not in header_set:
+            headers.append(("Server", "TornadoServer/%s" % tornado.version))
+
+        start_line = httputil.ResponseStartLine("HTTP/1.1", status_code, reason)
+        header_obj = httputil.HTTPHeaders()
+        for key, value in headers:
+            header_obj.add(key, value)
+        assert request.connection is not None
+        request.connection.write_headers(start_line, header_obj, chunk=body)
+        request.connection.finish()
+        self._log(status_code, request)
+
+    def environ(self, request: httputil.HTTPServerRequest) -> Dict[Text, Any]:
+        """Converts a `tornado.httputil.HTTPServerRequest` to a WSGI environment.
+
+        .. versionchanged:: 6.3
+           No longer a static method.
+        """
+        hostport = request.host.split(":")
+        if len(hostport) == 2:
+            host = hostport[0]
+            port = int(hostport[1])
+        else:
+            host = request.host
+            port = 443 if request.protocol == "https" else 80
+        environ = {
+            "REQUEST_METHOD": request.method,
+            "SCRIPT_NAME": "",
+            "PATH_INFO": to_wsgi_str(
+                escape.url_unescape(request.path, encoding=None, plus=False)
+            ),
+            "QUERY_STRING": request.query,
+            "REMOTE_ADDR": request.remote_ip,
+            "SERVER_NAME": host,
+            "SERVER_PORT": str(port),
+            "SERVER_PROTOCOL": request.version,
+            "wsgi.version": (1, 0),
+            "wsgi.url_scheme": request.protocol,
+            "wsgi.input": BytesIO(escape.utf8(request.body)),
+            "wsgi.errors": sys.stderr,
+            "wsgi.multithread": self.executor is not dummy_executor,
+            "wsgi.multiprocess": True,
+            "wsgi.run_once": False,
+        }
+        if "Content-Type" in request.headers:
+            environ["CONTENT_TYPE"] = request.headers.pop("Content-Type")
+        if "Content-Length" in request.headers:
+            environ["CONTENT_LENGTH"] = request.headers.pop("Content-Length")
+        for key, value in request.headers.items():
+            environ["HTTP_" + key.replace("-", "_").upper()] = value
+        return environ
+
+    def _log(self, status_code: int, request: httputil.HTTPServerRequest) -> None:
+        if status_code < 400:
+            log_method = access_log.info
+        elif status_code < 500:
+            log_method = access_log.warning
+        else:
+            log_method = access_log.error
+        request_time = 1000.0 * request.request_time()
+        assert request.method is not None
+        assert request.uri is not None
+        summary = (
+            request.method  # type: ignore[operator]
+            + " "
+            + request.uri
+            + " ("
+            + request.remote_ip
+            + ")"
+        )
+        log_method("%d %s %.2fms", status_code, summary, request_time)
+
+
+HTTPRequest = httputil.HTTPServerRequest