secure avatar to s3 by exception control

app/auth.py

@@ -73,14 +73,25 @@ async def auth_callback(request: Request, code: str, state: str):
 
     db = SessionLocal()
     
+    try:
         user = db.query(User).filter(User.email == user_info["email"]).first()
 
         if not user:
+            # 提取邮箱前缀作为 handle 基础
+            # 比如 "john.doe@gmail.com" -> "john_doe"
+            base_handle = user_info["email"].split("@")[0].replace(".", "_").lower()
+            
+            # 拼接一个随机短字符串，确保 handle 的唯一性
+            import secrets
+            random_suffix = secrets.token_hex(3) # 生成 6 位随机字符
+            suggested_handle = f"{base_handle}_{random_suffix}"
+            
             user = User(
                 google_id=user_info["id"],
                 email=user_info["email"],
                 name=user_info["name"],
                 avatar=user_info["picture"],
+                handle=suggested_handle,
             )
             db.add(user)
             db.commit()
@@ -88,14 +99,17 @@ async def auth_callback(request: Request, code: str, state: str):
             
             # 异步/同步将头像转存到 S3
             from app.utils.s3 import upload_google_avatar_to_s3
+            try:
                 s3_avatar_url = await upload_google_avatar_to_s3(user_info["picture"], str(user.id))
-        
                 # 将更新后的 S3 URL 写回数据库
                 user.avatar = s3_avatar_url
                 db.commit()
+            except Exception as s3_err:
+                print(f"S3 Upload failed: {s3_err}")
+            
             # 这里不需要再次 refresh，除非后面还要用到更新后的 user 对象
             # db.refresh(user)
-
+    finally:
         db.close()
 
     jwt_token = create_jwt_token({