update:优化了websocket对数据库连接的获取与释放

app/exception.py

@@ -46,6 +46,11 @@ class SessionNotFoundError(Exception):
         super().__init__(message)
         self.message = message
 
+class LlmResultNoneError(Exception):
+    def __init__(self, message="LLM Result is None!"):
+        super().__init__(message)
+        self.message = message
+
 # 大模型返回结束(非异常)
 class LLMResponseEnd(Exception):
     def __init__(self, message="LLM Response End!"):