连接 socket.io 时由于 xhr poll 错误而出现 connect_error

Posted 2023-03-15

【中文标题】连接 socket.io 时由于 xhr poll 错误而出现 connect_error

【英文标题】：Getting connect_error due to xhr poll error while connection of socket.io

【发布时间】：2021-10-07 19:26:58

【问题描述】：

我使用的是 socket.io 版本 4.1.3 我期待连接到服务器但收到错误 polling-xhr.js:198 GET http://localhost:7000/socket.io/?EIO=4&transport=polling&t=Ni6qzFI 404（未找到）

服务器端：

import express from 'express';
import bodyParser from 'body-parser';
import cors from 'cors';
import mongoose from 'mongoose';
import  createServer  from 'http';
import  Server  from 'socket.io';
import postRoutes from './routes/routes.js';

const app = express();
app.use(bodyParser.json( limit: '30 mb', extended: true ));
app.use(bodyParser.urlencoded( limit: '30 mb', extended: true ));


app.use(cors());

//routes

app.use('/posts', postRoutes);
//database
const CONNECTION_URL = 'mongodb+srv://mernpratice:[e-mail]/myFirstDatabase?retryWrites=true&w=majority';
const PORT = process.env.PORT || 7000;
const http = createServer(app);
const io = new Server(http, 
  cors:
    origin:'*',
  
);


io.on('connection', socket => 
  console.log('Conection to socket.io');
  socket.on('message', ( name, message ) => 
    io.emit('message',  name, message )
  )
);

mongoose.connect(CONNECTION_URL,  useNewUrlParser: true, useUnifiedTopology: true )
  .then(() => app.listen(PORT, () => console.log(`Server Running on Port: http://localhost:$PORT`)))
  .catch((error) => console.log(`$error did not connect`));

mongoose.set('useFindAndModify', false);

和客户端

import io from 'socket.io-client';

const socket = io.connect('http://localhost:7000');

socket.on("connect_error", (err) => 
    console.log(`connect_error due to $err.message`);
  );

谢谢。

【参考方案1】：

原来我在 mongoose 和 socket.io 上使用 diff 服务器 当我设置创建常量并用于两者时，问题就解决了。

import express from 'express';
import bodyParser from 'body-parser';
import cors from 'cors';
import mongoose from 'mongoose';
import  createServer  from 'http';
import  Server  from 'socket.io';
import postRoutes from './routes/routes.js';

const app = express();
app.use(bodyParser.json( limit: '30 mb', extended: true ));
app.use(bodyParser.urlencoded( limit: '30 mb', extended: true ));


app.use(cors());

//routes

app.use('/posts', postRoutes);
//database
const CONNECTION_URL = 'mongodb+srv://mernpratice:[e-mail]/myFirstDatabase?retryWrites=true&w=majority';
const PORT = process.env.PORT || 7000;

const server = app.listen(PORT, () => 
  console.log("Listening on port: " + PORT);
);


mongoose.connect(CONNECTION_URL,  useNewUrlParser: true, useUnifiedTopology: true )
  .then(() => server )
  .catch((error) => console.log(`$error did not connect`));

mongoose.set('useFindAndModify', false);


const io = new Server(server, 
  cors:
    origin:'*',
  
);


io.on('connection', socket => 
  console.log('Conection to socket.io');
  socket.on('message', ( name, message ) => 
    io.emit('message',  name, message )
  )
);