Source code for langchain_community.chat_message_histories.redis

import json
import logging
from typing import List, Optional

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

from langchain_community.utilities.redis import get_client

logger = logging.getLogger(__name__)


[docs]class RedisChatMessageHistory(BaseChatMessageHistory): """Chat message history stored in a Redis database."""
[docs] def __init__( self, session_id: str, url: str = "redis://localhost:6379/0", key_prefix: str = "message_store:", ttl: Optional[int] = None, ): try: import redis except ImportError: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) try: self.redis_client = get_client(redis_url=url) except redis.exceptions.ConnectionError as error: logger.error(error) self.session_id = session_id self.key_prefix = key_prefix self.ttl = ttl
@property def key(self) -> str: """Construct the record key to use""" return self.key_prefix + self.session_id @property def messages(self) -> List[BaseMessage]: """Retrieve the messages from Redis""" _items = self.redis_client.lrange(self.key, 0, -1) items = [json.loads(m.decode("utf-8")) for m in _items[::-1]] messages = messages_from_dict(items) return messages @messages.setter def messages(self, messages: List[BaseMessage]) -> None: raise NotImplementedError( "Direct assignment to 'messages' is not allowed." " Use the 'add_messages' instead." )
[docs] def add_message(self, message: BaseMessage) -> None: """Append the message to the record in Redis""" self.redis_client.lpush(self.key, json.dumps(message_to_dict(message))) if self.ttl: self.redis_client.expire(self.key, self.ttl)
[docs] def clear(self) -> None: """Clear session memory from Redis""" self.redis_client.delete(self.key)