_get_chat_history() — langchain Function Reference

Architecture documentation for the _get_chat_history() function in base.py from the langchain codebase.

Function python AgentOrchestration ClassicChains

Entity Profile

AgentOrchestration→ ClassicChains→ _get_chat_history() — langchain Function Reference

Dependency Diagram

graph TD
  867720c0_1f85_5f33_71c5_0415d18e7f52["_get_chat_history()"]
  94993a4e_2523_282e_bb19_84e4ccbd2c96["base.py"]
  867720c0_1f85_5f33_71c5_0415d18e7f52 -->|defined in| 94993a4e_2523_282e_bb19_84e4ccbd2c96
  style 867720c0_1f85_5f33_71c5_0415d18e7f52 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain/langchain_classic/chains/conversational_retrieval/base.py lines 45–65

def _get_chat_history(chat_history: list[CHAT_TURN_TYPE]) -> str:
    buffer = ""
    for dialogue_turn in chat_history:
        if isinstance(dialogue_turn, BaseMessage):
            if len(dialogue_turn.content) > 0:
                role_prefix = _ROLE_MAP.get(
                    dialogue_turn.type,
                    f"{dialogue_turn.type}: ",
                )
                buffer += f"\n{role_prefix}{dialogue_turn.content}"
        elif isinstance(dialogue_turn, tuple):
            human = "Human: " + dialogue_turn[0]
            ai = "Assistant: " + dialogue_turn[1]
            buffer += f"\n{human}\n{ai}"
        else:
            msg = (  # type: ignore[unreachable]
                f"Unsupported chat history format: {type(dialogue_turn)}."
                f" Full chat history: {chat_history} "
            )
            raise ValueError(msg)  # noqa: TRY004
    return buffer