3 files changed, 111 insertions, 42 deletions

diff --git a/g4f/providers/base_provider.py b/g4f/providers/base_provider.py
index b8649ba5..17c45875 100644
--- a/g4f/providers/base_provider.py
+++ b/g4f/providers/base_provider.py
@@ -270,7 +270,7 @@ class ProviderModelMixin:
     
     @classmethod
     def get_model(cls, model: str) -> str:
-        if not model:
+        if not model and cls.default_model is not None:
             model = cls.default_model
         elif model in cls.model_aliases:
             model = cls.model_aliases[model]
diff --git a/g4f/providers/retry_provider.py b/g4f/providers/retry_provider.py
index a7ab2881..52f473e9 100644
--- a/g4f/providers/retry_provider.py
+++ b/g4f/providers/retry_provider.py
@@ -3,22 +3,37 @@ from __future__ import annotations
 import asyncio
 import random
 
-from ..typing import CreateResult, Messages
-from .types import BaseRetryProvider
+from ..typing import Type, List, CreateResult, Messages, Iterator
+from .types import BaseProvider, BaseRetryProvider
 from .. import debug
 from ..errors import RetryProviderError, RetryNoProviderError
 
 class RetryProvider(BaseRetryProvider):
+    def __init__(
+        self,
+        providers: List[Type[BaseProvider]],
+        shuffle: bool = True
+    ) -> None:
+        """
+        Initialize the BaseRetryProvider.
+
+        Args:
+            providers (List[Type[BaseProvider]]): List of providers to use.
+            shuffle (bool): Whether to shuffle the providers list.
+        """
+        self.providers = providers
+        self.shuffle = shuffle
+        self.working = True
+        self.last_provider: Type[BaseProvider] = None
+
     """
     A provider class to handle retries for creating completions with different providers.
 
     Attributes:
         providers (list): A list of provider instances.
         shuffle (bool): A flag indicating whether to shuffle providers before use.
-        exceptions (dict): A dictionary to store exceptions encountered during retries.
         last_provider (BaseProvider): The last provider that was used.
     """
-
     def create_completion(
         self,
         model: str,
@@ -44,7 +59,7 @@ class RetryProvider(BaseRetryProvider):
         if self.shuffle:
             random.shuffle(providers)
 
-        self.exceptions = {}
+        exceptions = {}
         started: bool = False
         for provider in providers:
             self.last_provider = provider
@@ -57,13 +72,13 @@ class RetryProvider(BaseRetryProvider):
                 if started:
                     return
             except Exception as e:
-                self.exceptions[provider.__name__] = e
+                exceptions[provider.__name__] = e
                 if debug.logging:
                     print(f"{provider.__name__}: {e.__class__.__name__}: {e}")
                 if started:
                     raise e
 
-        self.raise_exceptions()
+        raise_exceptions(exceptions)
 
     async def create_async(
         self,
@@ -88,7 +103,7 @@ class RetryProvider(BaseRetryProvider):
         if self.shuffle:
             random.shuffle(providers)
 
-        self.exceptions = {}
+        exceptions = {}
         for provider in providers:
             self.last_provider = provider
             try:
@@ -97,23 +112,94 @@ class RetryProvider(BaseRetryProvider):
                     timeout=kwargs.get("timeout", 60)
                 )
             except Exception as e:
-                self.exceptions[provider.__name__] = e
+                exceptions[provider.__name__] = e
                 if debug.logging:
                     print(f"{provider.__name__}: {e.__class__.__name__}: {e}")
 
-        self.raise_exceptions()
+        raise_exceptions(exceptions)
 
-    def raise_exceptions(self) -> None:
-        """
-        Raise a combined exception if any occurred during retries.
+class IterProvider(BaseRetryProvider):
+    __name__ = "IterProvider"
 
-        Raises:
-            RetryProviderError: If any provider encountered an exception.
-            RetryNoProviderError: If no provider is found.
-        """
-        if self.exceptions:
-            raise RetryProviderError("RetryProvider failed:\n" + "\n".join([
-                f"{p}: {exception.__class__.__name__}: {exception}" for p, exception in self.exceptions.items()
-            ]))
+    def __init__(
+        self,
+        providers: List[BaseProvider],
+    ) -> None:
+        providers.reverse()
+        self.providers: List[BaseProvider] = providers
+        self.working: bool = True
+        self.last_provider: BaseProvider = None
+
+    def create_completion(
+        self,
+        model: str,
+        messages: Messages,
+        stream: bool = False,
+        **kwargs
+    ) -> CreateResult:
+        exceptions: dict = {}
+        started: bool = False
+        for provider in self.iter_providers():
+            if stream and not provider.supports_stream:
+                continue
+            try:
+                for token in provider.create_completion(model, messages, stream, **kwargs):
+                    yield token
+                    started = True
+                if started:
+                    return
+            except Exception as e:
+                exceptions[provider.__name__] = e
+                if debug.logging:
+                    print(f"{provider.__name__}: {e.__class__.__name__}: {e}")
+                if started:
+                    raise e
+        raise_exceptions(exceptions)
+
+    async def create_async(
+        self,
+        model: str,
+        messages: Messages,
+        **kwargs
+    ) -> str:
+        exceptions: dict = {}
+        for provider in self.iter_providers():
+            try:
+                return await asyncio.wait_for(
+                    provider.create_async(model, messages, **kwargs),
+                    timeout=kwargs.get("timeout", 60)
+                )
+            except Exception as e:
+                exceptions[provider.__name__] = e
+                if debug.logging:
+                    print(f"{provider.__name__}: {e.__class__.__name__}: {e}")
+        raise_exceptions(exceptions)
+
+    def iter_providers(self) -> Iterator[BaseProvider]:
+        used_provider = []
+        try:
+            while self.providers:
+                provider = self.providers.pop()
+                used_provider.append(provider)
+                self.last_provider = provider
+                if debug.logging:
+                    print(f"Using {provider.__name__} provider")
+                yield provider
+        finally:
+            used_provider.reverse()
+            self.providers = [*used_provider, *self.providers]
+
+def raise_exceptions(exceptions: dict) -> None:
+    """
+    Raise a combined exception if any occurred during retries.
+
+    Raises:
+        RetryProviderError: If any provider encountered an exception.
+        RetryNoProviderError: If no provider is found.
+    """
+    if exceptions:
+        raise RetryProviderError("RetryProvider failed:\n" + "\n".join([
+            f"{p}: {exception.__class__.__name__}: {exception}" for p, exception in exceptions.items()
+        ]))
 
-        raise RetryNoProviderError("No provider found")
\ No newline at end of file
+    raise RetryNoProviderError("No provider found")
\ No newline at end of file
diff --git a/g4f/providers/types.py b/g4f/providers/types.py
index 7b11ec43..67340958 100644
--- a/g4f/providers/types.py
+++ b/g4f/providers/types.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from typing import Union, List, Dict, Type
+from typing import Union, Dict, Type
 from ..typing import Messages, CreateResult
 
 class BaseProvider(ABC):
@@ -26,6 +26,7 @@ class BaseProvider(ABC):
     supports_gpt_35_turbo: bool = False
     supports_gpt_4: bool = False
     supports_message_history: bool = False
+    supports_system_message: bool = False
     params: str
 
     @classmethod
@@ -96,22 +97,4 @@ class BaseRetryProvider(BaseProvider):
     __name__: str = "RetryProvider"
     supports_stream: bool = True
 
-    def __init__(
-        self,
-        providers: List[Type[BaseProvider]],
-        shuffle: bool = True
-    ) -> None:
-        """
-        Initialize the BaseRetryProvider.
-
-        Args:
-            providers (List[Type[BaseProvider]]): List of providers to use.
-            shuffle (bool): Whether to shuffle the providers list.
-        """
-        self.providers = providers
-        self.shuffle = shuffle
-        self.working = True
-        self.exceptions: Dict[str, Exception] = {}
-        self.last_provider: Type[BaseProvider] = None
-
 ProviderType = Union[Type[BaseProvider], BaseRetryProvider]
\ No newline at end of file