Source code for langchain_community.chat_message_histories.file

import json
from pathlib import Path
from typing import List

from langchain_core.chat_history import (
    BaseChatMessageHistory,
)
from langchain_core.messages import BaseMessage, messages_from_dict, messages_to_dict


class FileChatMessageHistory(BaseChatMessageHistory):
    """存储聊天消息历史记录在本地文件中。"""

    def __init__(self, file_path: str) -> None:
        """初始化聊天记录文件路径。

参数：
    file_path：存储聊天记录的本地文件路径。
"""
        self.file_path = Path(file_path)
        if not self.file_path.exists():
            self.file_path.touch()
            self.file_path.write_text(json.dumps([]))

    @property
    def messages(self) -> List[BaseMessage]:  # type: ignore
        """从本地文件中检索消息"""
        items = json.loads(self.file_path.read_text())
        messages = messages_from_dict(items)
        return messages

    def add_message(self, message: BaseMessage) -> None:
        """将消息附加到本地文件中的记录"""
        messages = messages_to_dict(self.messages)
        messages.append(messages_to_dict([message])[0])
        self.file_path.write_text(json.dumps(messages))

    def clear(self) -> None:
        """清除本地文件中的会话内存"""
        self.file_path.write_text(json.dumps([]))