refactor(chat): remove db parameter from update_chat_title_from_message and manage DB session internally

api/routers/chats.py

@@ -152,7 +152,6 @@ async def post_message_and_get_response(
     if is_first_user_message:
         background_tasks.add_task(
             chat_crud.update_chat_title_from_message,
-            db=db,
             chat_id=chat.id,
             message_content=message_in.content
         )

db/crud/chat.py

@@ -5,8 +5,12 @@ from typing import Optional
 from sqlmodel import Session, select
 from sqlmodel.ext.asyncio.session import AsyncSession
 from sqlalchemy.orm import selectinload, raiseload
+
 from db.models.chat import Chat
+from db.session import async_engine
 from db.schemas.chat import ChatUpdate
+from workflow.title_generator import generate_chat_title
+
 
 from workflow.title_generator import generate_chat_title
 
@@ -48,27 +52,26 @@ async def update_chat_title(db: AsyncSession, chat: Chat, chat_update: ChatUpdat
     await db.refresh(chat)
     return chat
 
-async def update_chat_title_from_message(db: AsyncSession, chat_id: uuid.UUID, message_content: str):
+async def update_chat_title_from_message(chat_id: uuid.UUID, message_content: str):
     """
     Generates a title from a message and updates the chat record.
-    Designed to be run as a background task.
+    Designed to be run as a background task. It creates and closes its own DB session.
     """
-    try:
-        chat = await db.get(Chat, chat_id)
-        if not chat or chat.title != "New Chat":
-            # Chat doesn't exist or has already been titled, so we exit.
-            return
+    async with AsyncSession(async_engine) as db:
+        try:
+            chat = await db.get(Chat, chat_id)
+            # Only update if the chat exists and still has the default title
+            if not chat or chat.title != "New Chat":
+                return
 
-        new_title = await generate_chat_title(message_content)
-        if new_title:
-            chat.title = new_title
-            db.add(chat)
-            await db.commit()
-            print(f"INFO:     Background task updated title for chat {chat_id} to '{new_title}'")
-    except Exception as e:
-        print(f"ERROR:    Background task failed for chat {chat_id}: {e}")
-    finally:
-        await db.close() # Ensure the session is closed.
+            new_title = await generate_chat_title(message_content)
+            if new_title:
+                chat.title = new_title
+                db.add(chat)
+                await db.commit()
+                print(f"INFO:     Background task updated title for chat {chat_id} to '{new_title}'")
+        except Exception as e:
+            print(f"ERROR:    Background task failed for chat {chat_id}: {e}")
 
 async def delete_chat(db: AsyncSession, chat: Chat) -> None:
     """Deletes a chat from the database."""