CODEWITHSUNDEEP
pythonwebsocketaiohttp
Lera
Lera

Reputation: 21

Why websocket with aiohttp server doesn't work

I was trying to understand how websocket with aiohttp works, so I run this code from docunentation https://docs.aiohttp.org/en/stable/web_quickstart.html#websockets :

async def websocket_handler(request):

    ws = web.WebSocketResponse()
    await ws.prepare(request)

    async for msg in ws:
        if msg.type == aiohttp.WSMsgType.TEXT:
            if msg.data == 'close':
                await ws.close()
            else:
                await ws.send_str(msg.data + '/answer')
        elif msg.type == aiohttp.WSMsgType.ERROR:
            print('ws connection closed with exception %s' %
                  ws.exception())

    print('websocket connection closed')

    return ws

app = web.Application()
app.add_routes([web.get('/ws', websocket_handler)])


asyncio.run(web.run_app(app))

The result I examined with curl:

curl  http://0.0.0.0:8080/ws

The message that I saw was:

No WebSocket UPGRADE hdr: None
 Can "Upgrade" only to "WebSocket"

Firefox shows the same message.

What am I doing wrong? Maybe someone knows what is the problem?

Upvotes: 2

Views: 2175

Answers (1)

ugy
ugy

Reputation: 904

For anyone still confused why they can't test the aiohttp websocket example given above with websocat, it's worth noting that there is an issue with the current version (v1.11.0) via

brew install websocat

that means that localhost is not resolved properly.

It works fine if you substitute in 127.0.0.1 instead. For e.g:

websocat ws://127.0.0.1:8000/ws

Upvotes: 1

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