145 lines
4.5 KiB
Python
145 lines
4.5 KiB
Python
# -*- coding: utf-8 -*-
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"""Neo4j连接器模块
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本模块提供Neo4j图数据库的连接和查询功能。
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从 app/core/memory/src/database/neo4j_connector.py 迁移而来。
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Classes:
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Neo4jConnector: Neo4j数据库连接器，提供异步查询接口
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"""
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from typing import Any, List, Dict
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from neo4j import AsyncGraphDatabase, basic_auth
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from app.core.config import settings
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class Neo4jConnector:
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"""Neo4j数据库连接器
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提供与Neo4j图数据库的连接和查询功能。
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使用异步驱动程序以支持高并发操作。
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Attributes:
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driver: Neo4j异步驱动程序实例
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Methods:
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close: 关闭数据库连接
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execute_query: 执行Cypher查询
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delete_group: 删除指定组的所有数据
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"""
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def __init__(self):
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"""初始化Neo4j连接器
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从配置文件和环境变量中读取连接信息。
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Raises:
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RuntimeError: 如果NEO4J_PASSWORD环境变量未设置
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"""
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# 从全局配置和环境变量获取 Neo4j 配置
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uri = settings.NEO4J_URI
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username = settings.NEO4J_USERNAME
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password = settings.NEO4J_PASSWORD
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if not password:
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raise RuntimeError(
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"NEO4J_PASSWORD is not set. Create a .env with NEO4J_PASSWORD or export it before running."
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)
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self.driver = AsyncGraphDatabase.driver(
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uri,
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auth=basic_auth(username, password)
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)
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async def close(self):
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"""关闭数据库连接
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释放数据库连接资源。应在应用程序关闭时调用。
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"""
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await self.driver.close()
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async def execute_query(self, query: str, **kwargs: Any) -> List[Dict[str, Any]]:
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"""执行Cypher查询
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Args:
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query: Cypher查询语句
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**kwargs: 查询参数，将作为参数传递给Cypher查询
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Returns:
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List[Dict[str, Any]]: 查询结果列表，每个元素是一个字典
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Example:
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"""
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result = await self.driver.execute_query(
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query,
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database="neo4j",
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**kwargs
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)
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records, summary, keys = result
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return [record.data() for record in records]
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async def execute_write_transaction(self, transaction_func, **kwargs: Any) -> Any:
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"""在写事务中执行操作
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提供显式事务支持，确保操作的原子性。
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如果事务函数抛出异常，所有更改将自动回滚。
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Args:
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transaction_func: 事务函数，接收 tx 参数并执行查询
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**kwargs: 传递给事务函数的额外参数
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Returns:
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Any: 事务函数的返回值
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Example:
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"""
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async with self.driver.session(database="neo4j") as session:
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return await session.execute_write(transaction_func, **kwargs)
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async def execute_read_transaction(self, transaction_func, **kwargs: Any) -> Any:
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"""在读事务中执行操作
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提供显式事务支持用于读操作。
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Args:
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transaction_func: 事务函数，接收 tx 参数并执行查询
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**kwargs: 传递给事务函数的额外参数
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Returns:
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Any: 事务函数的返回值
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Example:
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"""
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async with self.driver.session(database="neo4j") as session:
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return await session.execute_read(transaction_func, **kwargs)
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async def delete_group(self, end_user_id: str):
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"""删除指定组的所有数据
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删除所有属于指定end_user_id的节点和边。
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这是一个危险操作，会永久删除数据。
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Args:
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end_user_id: 要删除的组ID
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Example:
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Group group_123 deleted.
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"""
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# 删除节点（DETACH DELETE会同时删除相关的边）
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await self.driver.execute_query(
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"MATCH (n) WHERE n.end_user_id = $end_user_id DETACH DELETE n",
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database="neo4j",
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end_user_id=end_user_id
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)
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# 删除独立的边（如果有的话）
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await self.driver.execute_query(
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"MATCH ()-[r]->() WHERE r.end_user_id = $end_user_id DELETE r",
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database="neo4j",
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end_user_id=end_user_id
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)
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print(f"Group {end_user_id} deleted.")
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