feat: has_emit_chunk优化

app/controller/add_langgraph_chat_route.py

@@ -86,8 +86,14 @@ def add_langgraph_chat_route(app: FastAPI):
     async def generator_function():
 
       graph = await ChatAgent.get_agent()
+
       # chat_state = await ChatAgent.get_chat_state(thread_id)
       # chat_history_list = chat_state.get('messages')
+
+      # has_emit_chunk 用来优化流式传输，避免将content为空的为AIMessageChunk发送给前端（实际上此时正在输出思考内容）
+      # 第一次的时候输出，后续再输出content为空的AIMessageChunk不发送给前端
+      has_emit_chunk = False
+
       async for chunk in graph.astream(
         stream_input,
         config=stream_config,
@@ -108,6 +114,7 @@ def add_langgraph_chat_route(app: FastAPI):
           # messages模式流式输出，此时 chunk[1][0] 为AIMessageChunk
           chunk_message = chunk[1][0]
           if not chunk_message.content:
+            if has_emit_chunk:
               continue
         else:
           # updates模式流式输出
@@ -125,6 +132,7 @@ def add_langgraph_chat_route(app: FastAPI):
           "msg_type": chunk_message.type,
           "msg_content": chunk_message.content,
         }
+        has_emit_chunk = True
 
         if isinstance(chunk_message, AIMessage):
           if chunk_message.tool_calls: