feat: Add base project structure with API and web components

api/app/repositories/neo4j/neo4j_connector.py

@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+"""Neo4j连接器模块
+
+本模块提供Neo4j图数据库的连接和查询功能。
+从 app/core/memory/src/database/neo4j_connector.py 迁移而来。
+
+Classes:
+    Neo4jConnector: Neo4j数据库连接器，提供异步查询接口
+"""
+
+import os
+from typing import Any, List, Dict
+
+from neo4j import AsyncGraphDatabase, basic_auth
+
+from app.core.config import settings
+
+
+class Neo4jConnector:
+    """Neo4j数据库连接器
+    
+    提供与Neo4j图数据库的连接和查询功能。
+    使用异步驱动程序以支持高并发操作。
+    
+    Attributes:
+        driver: Neo4j异步驱动程序实例
+        
+    Methods:
+        close: 关闭数据库连接
+        execute_query: 执行Cypher查询
+        delete_group: 删除指定组的所有数据
+    """
+    
+    def __init__(self):
+        """初始化Neo4j连接器
+        
+        从配置文件和环境变量中读取连接信息。
+        
+        Raises:
+            RuntimeError: 如果NEO4J_PASSWORD环境变量未设置
+        """
+        # 从全局配置和环境变量获取 Neo4j 配置
+        uri = settings.NEO4J_URI
+        username = settings.NEO4J_USERNAME
+        password = settings.NEO4J_PASSWORD
+        
+        if not password:
+            raise RuntimeError(
+                "NEO4J_PASSWORD is not set. Create a .env with NEO4J_PASSWORD or export it before running."
+            )
+        self.driver = AsyncGraphDatabase.driver(
+            uri,
+            auth=basic_auth(username, password)
+        )
+
+    async def close(self):
+        """关闭数据库连接
+        
+        释放数据库连接资源。应在应用程序关闭时调用。
+        """
+        await self.driver.close()
+
+    async def execute_query(self, query: str, **kwargs: Any) -> List[Dict[str, Any]]:
+        """执行Cypher查询
+        
+        Args:
+            query: Cypher查询语句
+            **kwargs: 查询参数，将作为参数传递给Cypher查询
+            
+        Returns:
+            List[Dict[str, Any]]: 查询结果列表，每个元素是一个字典
+            
+        Example:
+            >>> connector = Neo4jConnector()
+            >>> results = await connector.execute_query(
+            ...     "MATCH (n:Person {name: $name}) RETURN n",
+            ...     name="Alice"
+            ... )
+        """
+        result = await self.driver.execute_query(
+            query,
+            database="neo4j",
+            **kwargs
+        )
+        records, summary, keys = result
+        return [record.data() for record in records]
+    
+    async def delete_group(self, group_id: str):
+        """删除指定组的所有数据
+        
+        删除所有属于指定group_id的节点和边。
+        这是一个危险操作，会永久删除数据。
+        
+        Args:
+            group_id: 要删除的组ID
+            
+        Example:
+            >>> connector = Neo4jConnector()
+            >>> await connector.delete_group("group_123")
+            Group group_123 deleted.
+        """
+        # 删除节点（DETACH DELETE会同时删除相关的边）
+        await self.driver.execute_query(
+            "MATCH (n) WHERE n.group_id = $group_id DETACH DELETE n",
+            database="neo4j",
+            group_id=group_id
+        )
+        # 删除独立的边（如果有的话）
+        await self.driver.execute_query(
+            "MATCH ()-[r]->() WHERE r.group_id = $group_id DELETE r",
+            database="neo4j",
+            group_id=group_id
+        )
+        print(f"Group {group_id} deleted.")