前端修改

app/history.py

@@ -0,0 +1,178 @@
+"""
+历史对话查询模块
+利用 LangGraph 的 checkpointer 获取对话历史和摘要
+"""
+
+from typing import List, Dict, Any, Optional
+import logging
+from app.logger import error # 保持兼容，或者替换为 logger
+
+
+class ThreadHistoryService:
+    """线程历史查询服务"""
+    
+    def __init__(self, checkpointer):
+        self.checkpointer = checkpointer
+    
+    async def get_user_threads(self, user_id: str, limit: int = 50) -> List[Dict[str, Any]]:
+        """
+        获取指定用户的所有线程摘要信息
+        
+        Args:
+            user_id: 用户 ID
+            limit: 返回数量限制
+            
+        Returns:
+            线程列表，每个包含 thread_id, last_updated, summary, message_count
+        """
+        try:
+            # 查询 checkpoints 表获取用户的线程列表
+            async with self.checkpointer.conn.cursor() as cur:
+                # 查询每个线程的最新 checkpoint 和创建时间
+                query = """
+                    SELECT 
+                        thread_id,
+                        MAX(created_at) as last_updated
+                    FROM checkpoints
+                    WHERE metadata->>'user_id' = %s
+                    GROUP BY thread_id
+                    ORDER BY last_updated DESC
+                    LIMIT %s
+                """
+                await cur.execute(query, (user_id, limit))
+                rows = await cur.fetchall()
+                
+                threads = []
+                for row in rows:
+                    thread_id = row['thread_id']
+                    
+                    # 获取该线程的状态
+                    state = await self.checkpointer.aget_tuple({"configurable": {"thread_id": thread_id}})
+                    
+                    if state and state.values:
+                        messages = state.values.get("messages", [])
+                        summary = self._extract_summary(messages)
+                        message_count = len([m for m in messages if hasattr(m, 'type') and m.type in ["human", "ai"]])
+                        
+                        threads.append({
+                            "thread_id": thread_id,
+                            "last_updated": row['last_updated'].isoformat() if row['last_updated'] else "",
+                            "summary": summary,
+                            "message_count": message_count
+                        })
+                
+                return threads
+                
+        except Exception as e:
+            error(f"获取用户线程列表失败 (user_id={user_id}): {e}")
+            return []
+    
+    async def get_thread_messages(self, thread_id: str) -> List[Dict[str, str]]:
+        """
+        获取指定线程的完整消息历史
+        
+        Args:
+            thread_id: 线程 ID
+            
+        Returns:
+            消息列表，格式 [{"role": "user/assistant", "content": "..."}]
+        """
+        try:
+            state = await self.checkpointer.aget_tuple({"configurable": {"thread_id": thread_id}})
+            
+            if state is None or not state.values:
+                return []
+            
+            messages = state.values.get("messages", [])
+            
+            # 转换 LangChain 消息对象为字典
+            result = []
+            for msg in messages:
+                # 跳过 system 消息
+                if hasattr(msg, 'type') and msg.type == "system":
+                    continue
+                    
+                if hasattr(msg, 'type'):
+                    role = "user" if msg.type == "human" else "assistant" if msg.type == "ai" else msg.type
+                    result.append({
+                        "role": role,
+                        "content": msg.content
+                    })
+                elif isinstance(msg, dict):
+                    role = msg.get("role", msg.get("type", "unknown"))
+                    if role in ["human", "user"]:
+                        role = "user"
+                    elif role in ["ai", "assistant"]:
+                        role = "assistant"
+                    result.append({
+                        "role": role,
+                        "content": msg.get("content", "")
+                    })
+            
+            return result
+            
+        except Exception as e:
+            error(f"获取线程消息历史失败: {e}")
+            return []
+    
+    async def get_thread_summary(self, thread_id: str) -> Dict[str, Any]:
+        """
+        获取线程摘要（用于历史列表展示）
+        
+        Args:
+            thread_id: 线程 ID
+            
+        Returns:
+            包含摘要信息的字典
+        """
+        try:
+            state = await self.checkpointer.aget_tuple({"configurable": {"thread_id": thread_id}})
+            
+            if state is None or not state.values:
+                return {"thread_id": thread_id, "summary": "空对话", "message_count": 0}
+            
+            messages = state.values.get("messages", [])
+            summary = self._extract_summary(messages)
+            message_count = len([m for m in messages if hasattr(m, 'type') and m.type in ["human", "ai"]])
+            
+            # 获取最后更新时间
+            last_updated = ""
+            if state.metadata and "created_at" in state.metadata:
+                last_updated = state.metadata["created_at"].isoformat()
+            
+            return {
+                "thread_id": thread_id,
+                "summary": summary,
+                "message_count": message_count,
+                "last_updated": last_updated
+            }
+            
+        except Exception as e:
+            error(f"获取线程摘要失败: {e}")
+            return {"thread_id": thread_id, "summary": "加载失败", "message_count": 0}
+    
+    def _extract_summary(self, messages: List) -> str:
+        """
+        从消息列表中提取摘要
+        
+        策略：
+        1. 如果有 summarize 节点生成的 summary，优先使用
+        2. 否则使用第一条用户消息的前 50 字
+        """
+        # 查找是否有 summary 字段
+        for msg in messages:
+            if hasattr(msg, 'additional_kwargs') and msg.additional_kwargs.get('summary'):
+                return msg.additional_kwargs['summary']
+            elif isinstance(msg, dict) and msg.get('summary'):
+                return msg['summary']
+        
+        # 使用第一条用户消息作为摘要
+        for msg in messages:
+            if hasattr(msg, 'type') and msg.type == "human":
+                content = msg.content
+                return content[:50] + "..." if len(content) > 50 else content
+            elif isinstance(msg, dict) and msg.get("role") in ["user", "human"]:
+                content = msg.get("content", "")
+                return content[:50] + "..." if len(content) > 50 else content
+        
+        return "空对话"