使用Web套接字内部的同步功能来执行starlette [英] starlette, using a synchronous function inside a web socket

问题描述

我正在尝试使用starlette构建一个Web套接字，该消息接收消息，在同步函数中运行计算并返回响应.

I'm trying to build a web socket using starlette which receives a message, runs calculations in a synchronous function and returns a response.

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    while True:
        stock = await websocket.receive_text()
        stock = stock.upper()
        data = sentiment_analysis(stock=stock)
        await websocket.send_json({"score": data})

情感分析是一个同步功能.

the sentiment analysis is a synchronous function.

因此接收到文本并运行计算，并且如果我打印数据变量(字典)，我会看到它已正确返回，但是当我尝试将其发送回客户端时，出现以下错误:

so the text is received and the calculations are run and if I print the data variable (a dictionary), I see it's returned properly, but when I try to send it back to the client, I get the following error:

ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/uvicorn/protocols/websockets/websockets_impl.py", line 153, in run_asgi
    result = await self.app(self.scope, self.asgi_receive, self.asgi_send)
  File "/usr/lib/python3/dist-packages/uvicorn/middleware/proxy_headers.py", line 45, in __call__
    return await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/fastapi/applications.py", line 179, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/applications.py", line 111, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/middleware/errors.py", line 146, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/exceptions.py", line 58, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/routing.py", line 566, in __call__
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/routing.py", line 283, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/dist-packages/starlette/routing.py", line 57, in app
    await func(session)
  File "/usr/local/lib/python3.8/dist-packages/fastapi/routing.py", line 228, in app
    await dependant.call(**values)
  File "./app.py", line 13, in websocket_endpoint
    stock = await websocket.receive_text()
  File "/usr/local/lib/python3.8/dist-packages/starlette/websockets.py", line 85, in receive_text
    self._raise_on_disconnect(message)
  File "/usr/local/lib/python3.8/dist-packages/starlette/websockets.py", line 80, in _raise_on_disconnect
    raise WebSocketDisconnect(message["code"])
starlette.websockets.WebSocketDisconnect: 1011  

推荐答案

当客户端关闭连接时，您需要处理 WebSocketDisconnect 异常.可能是这样的:

You need to handle WebSocketDisconnect exception when a client closes the connection. It can be something like:

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()
    try:
        while True:
            stock = await websocket.receive_text()
            stock = stock.upper()
            data = sentiment_analysis(stock=stock)
            await websocket.send_json({"score": data})
    except WebSocketDisconnect:
        handle_exception()
        ...
    else:
        await websocket.close()

这篇关于使用Web套接字内部的同步功能来执行starlette的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！