Source code for langchain_community.chat_message_histories.firestore
"""Firestore 聊天消息历史。"""
from __future__ import annotations
import logging
from typing import TYPE_CHECKING, List, Optional
from langchain_core.chat_history import BaseChatMessageHistory
from langchain_core.messages import (
BaseMessage,
messages_from_dict,
messages_to_dict,
)
logger = logging.getLogger(__name__)
if TYPE_CHECKING:
from google.cloud.firestore import Client, DocumentReference
def _get_firestore_client() -> Client:
try:
import firebase_admin
from firebase_admin import firestore
except ImportError:
raise ImportError(
"Could not import firebase-admin python package. "
"Please install it with `pip install firebase-admin`."
)
# For multiple instances, only initialize the app once.
try:
firebase_admin.get_app()
except ValueError as e:
logger.debug("Initializing Firebase app: %s", e)
firebase_admin.initialize_app()
return firestore.client()
[docs]class FirestoreChatMessageHistory(BaseChatMessageHistory):
"""使用Google Firestore支持的聊天消息历史记录。"""
[docs] def __init__(
self,
collection_name: str,
session_id: str,
user_id: str,
firestore_client: Optional[Client] = None,
):
"""初始化一个新的FirestoreChatMessageHistory类的实例。
:param collection_name: 要使用的集合的名称。
:param session_id: 聊天会话的会话ID。
:param user_id: 聊天的用户ID。
"""
self.collection_name = collection_name
self.session_id = session_id
self.user_id = user_id
self._document: Optional[DocumentReference] = None
self.messages: List[BaseMessage] = []
self.firestore_client = firestore_client or _get_firestore_client()
self.prepare_firestore()
[docs] def prepare_firestore(self) -> None:
"""准备Firestore客户端。
使用此函数确保您的数据库已准备就绪。
"""
self._document = self.firestore_client.collection(
self.collection_name
).document(self.session_id)
self.load_messages()
[docs] def load_messages(self) -> None:
"""从Firestore中检索消息"""
if not self._document:
raise ValueError("Document not initialized")
doc = self._document.get()
if doc.exists:
data = doc.to_dict()
if "messages" in data and len(data["messages"]) > 0:
self.messages = messages_from_dict(data["messages"])
[docs] def add_message(self, message: BaseMessage) -> None:
self.messages.append(message)
self.upsert_messages()
[docs] def upsert_messages(self, new_message: Optional[BaseMessage] = None) -> None:
"""更新Firestore文档。"""
if not self._document:
raise ValueError("Document not initialized")
self._document.set(
{
"id": self.session_id,
"user_id": self.user_id,
"messages": messages_to_dict(self.messages),
}
)
[docs] def clear(self) -> None:
"""清除此内存和Firestore中的会话内存。"""
self.messages = []
if self._document:
self._document.delete()