_convert_message_to_dict() — langchain Function Reference

Source Code

libs/partners/openai/langchain_openai/chat_models/base.py lines 289–366

def _convert_message_to_dict(
    message: BaseMessage,
    api: Literal["chat/completions", "responses"] = "chat/completions",
) -> dict:
    """Convert a LangChain message to dictionary format expected by OpenAI."""
    message_dict: dict[str, Any] = {
        "content": _format_message_content(message.content, api=api, role=message.type)
    }
    if (name := message.name or message.additional_kwargs.get("name")) is not None:
        message_dict["name"] = name

    # populate role and additional message data
    if isinstance(message, ChatMessage):
        message_dict["role"] = message.role
    elif isinstance(message, HumanMessage):
        message_dict["role"] = "user"
    elif isinstance(message, AIMessage):
        message_dict["role"] = "assistant"
        if message.tool_calls or message.invalid_tool_calls:
            message_dict["tool_calls"] = [
                _lc_tool_call_to_openai_tool_call(tc) for tc in message.tool_calls
            ] + [
                _lc_invalid_tool_call_to_openai_tool_call(tc)
                for tc in message.invalid_tool_calls
            ]
        elif "tool_calls" in message.additional_kwargs:
            message_dict["tool_calls"] = message.additional_kwargs["tool_calls"]
            tool_call_supported_props = {"id", "type", "function"}
            message_dict["tool_calls"] = [
                {k: v for k, v in tool_call.items() if k in tool_call_supported_props}
                for tool_call in message_dict["tool_calls"]
            ]
        elif "function_call" in message.additional_kwargs:
            # OpenAI raises 400 if both function_call and tool_calls are present in the
            # same message.
            message_dict["function_call"] = message.additional_kwargs["function_call"]
        else:
            pass
        # If tool calls present, content null value should be None not empty string.
        if "function_call" in message_dict or "tool_calls" in message_dict:
            message_dict["content"] = message_dict["content"] or None

        audio: dict[str, Any] | None = None
        for block in message.content:
            if (
                isinstance(block, dict)
                and block.get("type") == "audio"
                and (id_ := block.get("id"))
                and api != "responses"
            ):
                # openai doesn't support passing the data back - only the id
                # https://platform.openai.com/docs/guides/audio/multi-turn-conversations
                audio = {"id": id_}
        if not audio and "audio" in message.additional_kwargs:
            raw_audio = message.additional_kwargs["audio"]
            audio = (
                {"id": message.additional_kwargs["audio"]["id"]}
                if "id" in raw_audio
                else raw_audio
            )
        if audio:
            message_dict["audio"] = audio
    elif isinstance(message, SystemMessage):
        message_dict["role"] = message.additional_kwargs.get(
            "__openai_role__", "system"
        )
    elif isinstance(message, FunctionMessage):
        message_dict["role"] = "function"
    elif isinstance(message, ToolMessage):
        message_dict["role"] = "tool"
        message_dict["tool_call_id"] = message.tool_call_id

        supported_props = {"content", "role", "tool_call_id"}
        message_dict = {k: v for k, v in message_dict.items() if k in supported_props}
    else:
        msg = f"Got unknown type {message}"
        raise TypeError(msg)
    return message_dict