Source code for langchain_community.chat_message_histories.neo4j
from typing import List, Optional, Union
from langchain_core.chat_history import BaseChatMessageHistory
from langchain_core.messages import BaseMessage, messages_from_dict
from langchain_core.utils import get_from_env
[docs]class Neo4jChatMessageHistory(BaseChatMessageHistory):
    """Chat message history stored in a Neo4j database."""
[docs]    def __init__(
        self,
        session_id: Union[str, int],
        url: Optional[str] = None,
        username: Optional[str] = None,
        password: Optional[str] = None,
        database: str = "neo4j",
        node_label: str = "Session",
        window: int = 3,
    ):
        try:
            import neo4j
        except ImportError:
            raise ValueError(
                "Could not import neo4j python package. "
                "Please install it with `pip install neo4j`."
            )
        # Make sure session id is not null
        if not session_id:
            raise ValueError("Please ensure that the session_id parameter is provided")
        url = get_from_env("url", "NEO4J_URI", url)
        username = get_from_env("username", "NEO4J_USERNAME", username)
        password = get_from_env("password", "NEO4J_PASSWORD", password)
        database = get_from_env("database", "NEO4J_DATABASE", database)
        self._driver = neo4j.GraphDatabase.driver(url, auth=(username, password))
        self._database = database
        self._session_id = session_id
        self._node_label = node_label
        self._window = window
        # Verify connection
        try: