feat:增加存储用户对话记录

services/agent_service.py

@@ -0,0 +1,80 @@
+from langchain_core.messages import HumanMessage, AIMessageChunk, AIMessage
+
+from agent import agent, checkpointer, title_agent
+from model import ChatRequest
+from services.db_service import exists_session, save_session
+from utils import dicts_to_messages
+
+
+def generate_title(messages: list[dict[str, str]]) -> str:
+    response = title_agent.invoke({
+        "messages": dicts_to_messages(messages)
+    })
+    return response["messages"][-1].content.strip()
+
+
+async def search_recipes(request: ChatRequest):
+    """调用agent搜索食谱"""
+    print(f"[用户] {request.username}: {request.message}, thread_id: {request.thread_id}")
+    try:
+        message = HumanMessage(content=request.message)
+
+        # 流式调用Agent
+        for chunk, metadata in agent.stream(
+                {"messages": [message]},
+                {"configurable": {"thread_id": request.thread_id}},
+                stream_mode="messages"
+        ):
+            if isinstance(chunk, AIMessageChunk) and chunk.content:
+                yield chunk.content
+
+        # 总结对话标题并保存
+        if not exists_session(request.thread_id, request.username):
+            title = generate_title(get_messages(request.thread_id))
+            save_session(request.thread_id, request.username, title)
+
+    except Exception as e:
+        print(f"\n[错误]: {str(e)}")
+        yield "信息检索失败，试试看手动输入食物列表？"
+
+
+# 清空会话
+def clear_messages(thread_id: str):
+    """清空会话"""
+    print(f"清空历史消息，thread_id: {thread_id}")
+    checkpointer.delete_thread(thread_id)
+
+
+# 查询会话历史
+def get_messages(thread_id: str) -> list[dict[str, str]]:
+    """获取会话历史"""
+    print(f"获取历史消息，thread_id: {thread_id}")
+
+    # 根据 thread_id 查询 checkpoint
+    checkpoint = checkpointer.get({"configurable": {"thread_id": thread_id}})
+
+    # 如果不存在，返回空列表
+    if not checkpoint:
+        return []
+
+    # 安全获取 messages
+    channel_values = checkpoint.get("channel_values")
+    if not channel_values:
+        return []
+
+    messages = channel_values.get("messages", [])
+    if not messages:
+        return []
+
+    # 转换消息格式
+    result = []
+    for msg in messages:
+        if not msg.content:
+            continue
+
+        if isinstance(msg, HumanMessage):
+            result.append({"role": "user", "content": msg.content})
+        elif isinstance(msg, AIMessage):
+            result.append({"role": "ai", "content": msg.content})
+
+    return result