from typing import Any, AsyncIterator, Dict, Iterator, List, Optional
from langchain_core._api.deprecation import deprecated
from langchain_core.callbacks import (
AsyncCallbackManagerForLLMRun,
CallbackManagerForLLMRun,
)
from langchain_core.language_models.chat_models import (
BaseChatModel,
agenerate_from_stream,
generate_from_stream,
)
from langchain_core.messages import (
AIMessage,
AIMessageChunk,
BaseMessage,
ChatMessage,
HumanMessage,
SystemMessage,
)
from langchain_core.outputs import ChatGeneration, ChatGenerationChunk, ChatResult
from langchain_community.llms.cohere import BaseCohere
[docs]def get_role(message: BaseMessage) -> str:
"""Get the role of the message.
Args:
message: The message.
Returns:
The role of the message.
Raises:
ValueError: If the message is of an unknown type.
"""
if isinstance(message, ChatMessage) or isinstance(message, HumanMessage):
return "User"
elif isinstance(message, AIMessage):
return "Chatbot"
elif isinstance(message, SystemMessage):
return "System"
else:
raise ValueError(f"Got unknown type {message}")
[docs]def get_cohere_chat_request(
messages: List[BaseMessage],
*,
connectors: Optional[List[Dict[str, str]]] = None,
**kwargs: Any,
) -> Dict[str, Any]:
"""Get the request for the Cohere chat API.
Args:
messages: The messages.
connectors: The connectors.
**kwargs: The keyword arguments.
Returns:
The request for the Cohere chat API.
"""
documents = (
None
if "source_documents" not in kwargs
else [
{
"snippet": doc.page_content,
"id": doc.metadata.get("id") or f"doc-{str(i)}",
}
for i, doc in enumerate(kwargs["source_documents"])
]
)
kwargs.pop("source_documents", None)
maybe_connectors = connectors if documents is None else None
# by enabling automatic prompt truncation, the probability of request failure is
# reduced with minimal impact on response quality
prompt_truncation = (
"AUTO" if documents is not None or connectors is not None else None
)
req = {
"message": messages[-1].content,
"chat_history": [
{"role": get_role(x), "message": x.content} for x in messages[:-1]
],
"documents": documents,
"connectors": maybe_connectors,
"prompt_truncation": prompt_truncation,
**kwargs,
}
return {k: v for k, v in req.items() if v is not None}
[docs]@deprecated(
since="0.0.30", removal="1.0", alternative_import="langchain_cohere.ChatCohere"
)
class ChatCohere(BaseChatModel, BaseCohere):
"""`Cohere` chat large language models.
To use, you should have the ``cohere`` python package installed, and the
environment variable ``COHERE_API_KEY`` set with your API key, or pass
it as a named parameter to the constructor.
Example:
.. code-block:: python
from langchain_community.chat_models import ChatCohere
from langchain_core.messages import HumanMessage
chat = ChatCohere(max_tokens=256, temperature=0.75)
messages = [HumanMessage(content="knock knock")]
chat.invoke(messages)
"""
class Config:
allow_population_by_field_name = True
arbitrary_types_allowed = True
@property
def _llm_type(self) -> str:
"""Return type of chat model."""
return "cohere-chat"
@property
def _default_params(self) -> Dict[str, Any]:
"""Get the default parameters for calling Cohere API."""
return {
"temperature": self.temperature,
}
@property
def _identifying_params(self) -> Dict[str, Any]:
"""Get the identifying parameters."""
return {**{"model": self.model}, **self._default_params}
def _stream(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> Iterator[ChatGenerationChunk]:
request = get_cohere_chat_request(messages, **self._default_params, **kwargs)
if hasattr(self.client, "chat_stream"): # detect and support sdk v5
stream = self.client.chat_stream(**request)
else:
stream = self.client.chat(**request, stream=True)
for data in stream:
if data.event_type == "text-generation":
delta = data.text
chunk = ChatGenerationChunk(message=AIMessageChunk(content=delta))
if run_manager:
run_manager.on_llm_new_token(delta, chunk=chunk)
yield chunk
async def _astream(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[AsyncCallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> AsyncIterator[ChatGenerationChunk]:
request = get_cohere_chat_request(messages, **self._default_params, **kwargs)
if hasattr(self.async_client, "chat_stream"): # detect and support sdk v5
stream = await self.async_client.chat_stream(**request)
else:
stream = await self.async_client.chat(**request, stream=True)
async for data in stream:
if data.event_type == "text-generation":
delta = data.text
chunk = ChatGenerationChunk(message=AIMessageChunk(content=delta))
if run_manager:
await run_manager.on_llm_new_token(delta, chunk=chunk)
yield chunk
def _get_generation_info(self, response: Any) -> Dict[str, Any]:
"""Get the generation info from cohere API response."""
return {
"documents": response.documents,
"citations": response.citations,
"search_results": response.search_results,
"search_queries": response.search_queries,
"token_count": response.token_count,
}
def _generate(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> ChatResult:
if self.streaming:
stream_iter = self._stream(
messages, stop=stop, run_manager=run_manager, **kwargs
)
return generate_from_stream(stream_iter)
request = get_cohere_chat_request(messages, **self._default_params, **kwargs)
response = self.client.chat(**request)
message = AIMessage(content=response.text)
generation_info = None
if hasattr(response, "documents"):
generation_info = self._get_generation_info(response)
return ChatResult(
generations=[
ChatGeneration(message=message, generation_info=generation_info)
]
)
async def _agenerate(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[AsyncCallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> ChatResult:
if self.streaming:
stream_iter = self._astream(
messages, stop=stop, run_manager=run_manager, **kwargs
)
return await agenerate_from_stream(stream_iter)
request = get_cohere_chat_request(messages, **self._default_params, **kwargs)
response = self.client.chat(**request)
message = AIMessage(content=response.text)
generation_info = None
if hasattr(response, "documents"):
generation_info = self._get_generation_info(response)
return ChatResult(
generations=[
ChatGeneration(message=message, generation_info=generation_info)
]
)
[docs] def get_num_tokens(self, text: str) -> int:
"""Calculate number of tokens."""
return len(self.client.tokenize(text=text).tokens)
