'use strict'
const diagnosticsChannel = require('diagnostics_channel')
const { uid, states } = require('./constants')
const {
kReadyState,
kSentClose,
kByteParser,
kReceivedClose
} = require('./symbols')
const { fireEvent, failWebsocketConnection } = require('./util')
const { CloseEvent } = require('./events')
const { makeRequest } = require('../fetch/request')
const { fetching } = require('../fetch/index')
const { Headers } = require('../fetch/headers')
const { getGlobalDispatcher } = require('../global')
const { kHeadersList } = require('../core/symbols')
const channels = {}
channels.open = diagnosticsChannel.channel('undici:websocket:open')
channels.close = diagnosticsChannel.channel('undici:websocket:close')
channels.socketError = diagnosticsChannel.channel('undici:websocket:socket_error')
/** @type {import('crypto')} */
let crypto
try {
crypto = require('crypto')
} catch {
}
/**
* @see https://websockets.spec.whatwg.org/#concept-websocket-establish
* @param {URL} url
* @param {string|string[]} protocols
* @param {import('./websocket').WebSocket} ws
* @param {(response: any) => void} onEstablish
* @param {Partial<import('../../types/websocket').WebSocketInit>} options
*/
function establishWebSocketConnection (url, protocols, ws, onEstablish, options) {
// 1. Let requestURL be a copy of url, with its scheme set to "http", if url’s
// scheme is "ws", and to "https" otherwise.
const requestURL = url
requestURL.protocol = url.protocol === 'ws:' ? 'http:' : 'https:'
// 2. Let request be a new request, whose URL is requestURL, client is client,
// service-workers mode is "none", referrer is "no-referrer", mode is
// "websocket", credentials mode is "include", cache mode is "no-store" ,
// and redirect mode is "error".
const request = makeRequest({
urlList: [requestURL],
serviceWorkers: 'none',
referrer: 'no-referrer',
mode: 'websocket',
credentials: 'include',
cache: 'no-store',
redirect: 'error'
})
// Note: undici extension, allow setting custom headers.
if (options.headers) {
const headersList = new Headers(options.headers)[kHeadersList]
request.headersList = headersList
}
// 3. Append (`Upgrade`, `websocket`) to request’s header list.
// 4. Append (`Connection`, `Upgrade`) to request’s header list.
// Note: both of these are handled by undici currently.
// https://github.com/nodejs/undici/blob/68c269c4144c446f3f1220951338daef4a6b5ec4/lib/client.js#L1397
// 5. Let keyValue be a nonce consisting of a randomly selected
// 16-byte value that has been forgiving-base64-encoded and
// isomorphic encoded.
const keyValue = crypto.randomBytes(16).toString('base64')
// 6. Append (`Sec-WebSocket-Key`, keyValue) to request’s
// header list.
request.headersList.append('sec-websocket-key', keyValue)
// 7. Append (`Sec-WebSocket-Version`, `13`) to request’s
// header list.
request.headersList.append('sec-websocket-version', '13')
// 8. For each protocol in protocols, combine
// (`Sec-WebSocket-Protocol`, protocol) in request’s header
// list.
for (const protocol of protocols) {
request.headersList.append('sec-websocket-protocol', protocol)
}
// 9. Let permessageDeflate be a user-agent defined
// "permessage-deflate" extension header value.
// https://github.com/mozilla/gecko-dev/blob/ce78234f5e653a5d3916813ff990f053510227bc/netwerk/protocol/websocket/WebSocketChannel.cpp#L2673
// TODO: enable once permessage-deflate is supported
const permessageDeflate = '' // 'permessage-deflate; 15'
// 10. Append (`Sec-WebSocket-Extensions`, permessageDeflate) to
// request’s header list.
// request.headersList.append('sec-websocket-extensions', permessageDeflate)
// 11. Fetch request with useParallelQueue set to true, and
// processResponse given response being these steps:
const controller = fetching({
request,
useParallelQueue: true,
dispatcher: options.dispatcher ?? getGlobalDispatcher(),
processResponse (response) {
// 1. If response is a network error or its status is not 101,
// fail the WebSocket connection.
if (response.type === 'error' || response.status !== 101) {
failWebsocketConnection(ws, 'Received network error or non-101 status code.')
return
}
// 2. If protocols is not the empty list and extracting header
// list values given `Sec-WebSocket-Protocol` and response’s
// header list results in null, failure, or the empty byte
// sequence, then fail the WebSocket connection.
if (protocols.length !== 0 && !response.headersList.get('Sec-WebSocket-Protocol')) {
failWebsocketConnection(ws, 'Server did not respond with sent protocols.')
return
}
// 3. Follow the requirements stated step 2 to step 6, inclusive,
// of the last set of steps in section 4.1 of The WebSocket
// Protocol to validate response. This either results in fail
// the WebSocket connection or the WebSocket connection is
// established.
// 2. If the response lacks an |Upgrade| header field or the |Upgrade|
// header field contains a value that is not an ASCII case-
// insensitive match for the value "websocket", the client MUST
// _Fail the WebSocket Connection_.
if (response.headersList.get('Upgrade')?.toLowerCase() !== 'websocket') {
failWebsocketConnection(ws, 'Server did not set Upgrade header to "websocket".')
return
}
// 3. If the response lacks a |Connection| header field or the
// |Connection| header field doesn't contain a token that is an
// ASCII case-insensitive match for the value "Upgrade", the client
// MUST _Fail the WebSocket Connection_.
if (response.headersList.get('Connection')?.toLowerCase() !== 'upgrade') {
failWebsocketConnection(ws, 'Server did not set Connection header to "upgrade".')
return
}
// 4. If the response lacks a |Sec-WebSocket-Accept| header field or
// the |Sec-WebSocket-Accept| contains a value other than the
// base64-encoded SHA-1 of the concatenation of the |Sec-WebSocket-
// Key| (as a string, not base64-decoded) with the string "258EAFA5-
// E914-47DA-95CA-C5AB0DC85B11" but ignoring any leading and
// trailing whitespace, the client MUST _Fail the WebSocket
// Connection_.
const secWSAccept = response.headersList.get('Sec-WebSocket-Accept')
const digest = crypto.createHash('sha1').update(keyValue + uid).digest('base64')
if (secWSAccept !== digest) {
failWebsocketConnection(ws, 'Incorrect hash received in Sec-WebSocket-Accept header.')
return
}
// 5. If the response includes a |Sec-WebSocket-Extensions| header
// field and this header field indicates the use of an extension
// that was not present in the client's handshake (the server has
// indicated an extension not requested by the client), the client
// MUST _Fail the WebSocket Connection_. (The parsing of this
// header field to determine which extensions are requested is
// discussed in Section 9.1.)
const secExtension = response.headersList.get('Sec-WebSocket-Extensions')
if (secExtension !== null && secExtension !== permessageDeflate) {
failWebsocketConnection(ws, 'Received different permessage-deflate than the one set.')
return
}
// 6. If the response includes a |Sec-WebSocket-Protocol| header field
// and this header field indicates the use of a subprotocol that was
// not present in the client's handshake (the server has indicated a
// subprotocol not requested by the client), the client MUST _Fail
// the WebSocket Connection_.
const secProtocol = response.headersList.get('Sec-WebSocket-Protocol')
if (secProtocol !== null && secProtocol !== request.headersList.get('Sec-WebSocket-Protocol')) {
failWebsocketConnection(ws, 'Protocol was not set in the opening handshake.')
return
}
response.socket.on('data', onSocketData)
response.socket.on('close', onSocketClose)
response.socket.on('error', onSocketError)
if (channels.open.hasSubscribers) {
channels.open.publish({
address: response.socket.address(),
protocol: secProtocol,
extensions: secExtension
})
}
onEstablish(response)
}
})
return controller
}
/**
* @param {Buffer} chunk
*/
function onSocketData (chunk) {
if (!this.ws[kByteParser].write(chunk)) {
this.pause()
}
}
/**
* @see https://websockets.spec.whatwg.org/#feedback-from-the-protocol
* @see https://datatracker.ietf.org/doc/html/rfc6455#section-7.1.4
*/
function onSocketClose () {
const { ws } = this
// If the TCP connection was closed after the
// WebSocket closing handshake was completed, the WebSocket connection
// is said to have been closed _cleanly_.
const wasClean = ws[kSentClose] && ws[kReceivedClose]
let code = 1005
let reason = ''
const result = ws[kByteParser].closingInfo
if (result) {
code = result.code ?? 1005
reason = result.reason
} else if (!ws[kSentClose]) {
// If _The WebSocket
// Connection is Closed_ and no Close control frame was received by the
// endpoint (such as could occur if the underlying transport connection
// is lost), _The WebSocket Connection Close Code_ is considered to be
// 1006.
code = 1006
}
// 1. Change the ready state to CLOSED (3).
ws[kReadyState] = states.CLOSED
// 2. If the user agent was required to fail the WebSocket
// connection, or if the WebSocket connection was closed
// after being flagged as full, fire an event named error
// at the WebSocket object.
// TODO
// 3. Fire an event named close at the WebSocket object,
// using CloseEvent, with the wasClean attribute
// initialized to true if the connection closed cleanly
// and false otherwise, the code attribute initialized to
// the WebSocket connection close code, and the reason
// attribute initialized to the result of applying UTF-8
// decode without BOM to the WebSocket connection close
// reason.
fireEvent('close', ws, CloseEvent, {
wasClean, code, reason
})
if (channels.close.hasSubscribers) {
channels.close.publish({
websocket: ws,
code,
reason
})
}
}
function onSocketError (error) {
const { ws } = this
ws[kReadyState] = states.CLOSING
if (channels.socketError.hasSubscribers) {
channels.socketError.publish(error)
}
this.destroy()
}
module.exports = {
establishWebSocketConnection
}
