未捕获的TypeError：无法读取未定义的属性'sid'

问题描述

我正在使用socket.io和python-socketio在python反应的应用程序中使用socket.io-client。客户端在连接到服务器时以及触发connect事件之前显示错误。

服务器：

import asyncio
from aiohttp import web
import socketio
from aiohttp_middlewares import cors_middleware
from aiohttp_middlewares.cors import DEFAULT_ALLOW_HEADERS
sio = socketio.AsyncServer(async_mode='aiohttp',cors_allowed_origins='*')
app=web.Application()
sio.attach(app)

async def index(request):
    return web.Response(text="hello",content_type='text/html')

@sio.event
async def connect(sid,environ):
    print('Client connected',sid)
    await sio.emit('message',"good")

@sio.event
def disconnect(sid):
    print('Client disconnected',sid)

@sio.on('message')
async def print_message(sid,message):
    print("Socket ID: ",sid)
    print(message)

app.router.add_get('/',index)

if __name__ == '__main__':
    web.run_app(app)

客户（反应）：

import io from "socket.io-client"
let socket;    
.
.
.
componentDidMount(){
    socket = io('http://localhost:8080/',{transports:['websocket'],upgrade:false});
    socket.on('connect',()=> {
        socket.on('message',(data)=>{console.log(data)})
    });
    socket.on('disconnect',() => {
        console.log(socket.connected);
    });
}

控制台中显示错误：

文件与socket.io-client

相关

Uncaught TypeError: Cannot read property 'sid' of undefined
    at Socket.onpacket (socket.js:189)
    at Manager.<anonymous> (index.js:21)
    at Manager.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
    at Manager.ondecoded (manager.js:209)
    at Decoder.<anonymous> (index.js:21)
    at Decoder.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
    at Decoder.add (index.js:117)
    at Manager.ondata (manager.js:201)
    at Socket.<anonymous> (index.js:21)
    at Socket.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
    at Socket.onPacket (socket.js:387)
    at WS.<anonymous> (socket.js:196)
    at WS.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
    at WS.onPacket (transport.js:103)
    at WS.onData (transport.js:96)
    at WebSocket.ws.onmessage (websocket.js:115)

解决方法

在Node.js上使用最新版本的socket.io-client时遇到相同的错误。如果我使用的是v2.3.0等旧版本，则不会出现任何错误。

我知道这次降级可以解决某些人的问题，但是如果您想使用最新版本（我不是socket.io的专家），请查看此帖子，他们在此谈论API的一些更改并解决一些不一致之处：

https://socket.io/docs/v3/migrating-from-2-x-to-3-0/index.html