feat：添加左侧历史对话列表

app/db/mongo.py

@@ -119,6 +119,30 @@ def delete_chat_history(user_id: str, session_id: str) -> int:
         return 0
 
 
+def get_sessions(user_id: str) -> list:
+    try:
+        pipeline = [
+            {"$match": {"user_id": user_id, "role": "user"}},
+            {"$sort": {"timestamp": 1}},
+            {"$group": {
+                "_id": "$session_id",
+                "createdAt": {"$first": "$timestamp"},
+                "preview": {"$first": "$content"},
+            }},
+            {"$sort": {"createdAt": -1}},
+            {"$project": {
+                "_id": 0,
+                "sessionId": "$_id",
+                "createdAt": 1,
+                "preview": {"$substrCP": ["$preview", 0, 20]},
+            }},
+        ]
+        return list(chat_history_col.aggregate(pipeline))
+    except Exception as e:
+        print(f"MongoDB 会话列表查询失败: {e}")
+        return []
+
+
 _DEFAULT_PROMPT_CONFIG = {
     "name": "兴趣圈",
     "role": "活跃用户",

app/routers/chat.py

@@ -4,12 +4,13 @@ from typing import List, Annotated, Optional
 from datetime import datetime
 import json
 import asyncio
+import threading
 
 from ..core.ark_client import config, client
 from ..schemas.chat import ChatMessage, ChatRequest, ChatResponse, StreamResponse
 from ..utils.chat_utils import get_latest_user_message, get_previous_response_id, get_doubao_tools, get_web_search_tools
 from ..routers.users import get_current_active_user, User
-from ..db.mongo import save_chat_log, save_chat_history, get_chat_history, delete_chat_history
+from ..db.mongo import save_chat_log, save_chat_history, get_chat_history, delete_chat_history, get_sessions
 from ..dependencies.auth import resolve_user_id
 
 router = APIRouter()
@@ -93,19 +94,37 @@ async def generate_stream_response(request: ChatRequest, user_id: str):
         accumulated_thinking = ""
         accumulated_searching = ""
         response_id = None
-        thinking_started = False
-        answering_started = False
+
+        # 将同步阻塞的 stream 迭代放入子线程，通过 Queue 传递给异步生成器
+        # 避免阻塞事件循环，保证每个 chunk 到达时立即 yield 推送给前端
+        loop = asyncio.get_event_loop()
+        queue: asyncio.Queue = asyncio.Queue()
+
+        def _iterate_stream():
+            try:
+                for chunk in stream:
+                    loop.call_soon_threadsafe(queue.put_nowait, chunk)
+            except Exception as e:
+                loop.call_soon_threadsafe(queue.put_nowait, e)
+            finally:
+                loop.call_soon_threadsafe(queue.put_nowait, None)  # 结束哨兵
+
+        threading.Thread(target=_iterate_stream, daemon=True).start()
 
         print("=== 边想边搜启动 ===")
-        for chunk in stream:
+        while True:
+            chunk = await queue.get()
+            if chunk is None:
+                break
+            if isinstance(chunk, Exception):
+                raise chunk
+
             chunk_type = getattr(chunk, 'type', '')
 
             # ① 处理AI思考过程
             if chunk_type == 'response.reasoning_summary_text.delta':
                 delta_text = getattr(chunk, 'delta', '')
                 if delta_text:
-                    if not thinking_started:
-                        thinking_started = True
                     accumulated_thinking += delta_text
                     yield f"data: {StreamResponse(content=delta_text, finished=False, model=config.MODEL_NAME, timestamp=datetime.now(), type='thinking').model_dump_json()}\n\n"
 
@@ -136,12 +155,8 @@ async def generate_stream_response(request: ChatRequest, user_id: str):
             elif chunk_type == 'response.output_text.delta':
                 delta_text = getattr(chunk, 'delta', '')
                 if delta_text:
-                    if not answering_started:
-                        # print(f"\n\n💬 AI回答 [{datetime.now().strftime('%H:%M:%S')}]:")
-                        answering_started = True
                     accumulated_content += delta_text
                     yield f"data: {StreamResponse(content=delta_text, finished=False, model=config.MODEL_NAME, timestamp=datetime.now()).model_dump_json()}\n\n"
-                    await asyncio.sleep(0.01)
 
             # ⑤ 处理响应完成事件
             elif chunk_type == 'response.completed':
@@ -347,6 +362,13 @@ async def clear_user_history(
     return {"message": "用户没有聊天历史", "user": current_user.userId, "deleted_messages": 0, "timestamp": datetime.now()}
 
 
+@router.get("/sessions")
+async def get_user_sessions(
+    current_user: Annotated[User, Depends(get_current_active_user)],
+):
+    return get_sessions(current_user.userId)
+
+
 @router.get("/health")
 async def health_check():
     return {"status": "healthy", "timestamp": datetime.now(), "version": "1.0.0", "model": config.MODEL_NAME}