Socket.io-client 未连接到 socket.io 服务器反应和节点（快递）答案

【问题标题】：Socket.io-client is not connecting to socket.io server react and node(express)Socket.io-client 未连接到 socket.io 服务器反应和节点（快递）
【发布时间】：2021-04-21 23:24:57
【问题描述】：

我尝试使用以下代码连接到 socket.io-client：

客户：

import queryString from 'query-string';
import React, { useEffect, useState } from 'react';
import io from 'socket.io-client';

let socket;

const Chat = ({location}) => {

const [name, setName] = useState("");
const [room, setRoom] = useState("");
const EP = 'http://localhost:5000/';

useEffect(() =>{
    const {name , room} = queryString.parse(location.search);

    socket = io(EP);

    setName(name);
    setRoom(room);

    console.log(socket);
},[EP, location.search])

return(
    <h1>helloooooooooooooo {name} welcome to {room}</h1>
)
}

export default Chat;

服务器：

const express = require('express');
const socketio = require('socket.io');
const http = require('http');
const router = require('./router/router');

const PORT = process.env.PORT ||5050;

const app = express();
const server = http.createServer(app);
const io = socketio(server);




//socket.io

io.on('connection', socket => {
console.log("we have a new user!!!!!!!!!");

socket.on('disconnect', () =>{
    console.log('User had left!');
})
})

// io.on('connection', socket => { 
//     console.log("we have a new user!!!!!!!!");

//     socket.on("disconnect", () => console.log("user is left"))        
//  });

app.use(router);

server.listen(PORT, () => console.log(`Server has started on ${PORT}`));

我没有从这个服务器套接字获取连接或断开控制台日志。我遵循与 socke.io doc 相同的流程。

console message from browser, its showing disconnected true and connected false and no id

【问题讨论】：

标签： node.js reactjs express socket.io

【解决方案1】：

在浏览器中，WebSocket 对象不支持附加标头。如果您想添加一些标头作为某些身份验证机制的一部分，您可以使用transportOptions 属性。请注意，在这种情况下，标头不会在 WebSocket 升级请求中发送。

 // WILL NOT WORK in the browser
    const socket = new Socket('http://localhost', {
      extraHeaders: {
        'X-Custom-Header-For-My-Project': 'will not be sent'
      }
    });
    // WILL NOT WORK
    const socket = new Socket('http://localhost', {
      transports: ['websocket'], // polling is disabled
      transportOptions: {
        polling: {
          extraHeaders: {
            'X-Custom-Header-For-My-Project': 'will not be sent'
          }
        }
      }
    });
    // WILL WORK
    const socket = new Socket('http://localhost', {
      transports: ['polling', 'websocket'],
      transportOptions: {
        polling: {
          extraHeaders: {
            'X-Custom-Header-For-My-Project': 'will be used'
          }
        }
      }
    });

信用：Engine.IO client

【讨论】：

【解决方案2】：

在客户端，在 useEffect 内部而不是

socket = io(EP);

到这里

socket = io.connect(EP , {
        "force new connection" : true,
        "reconnectionAttempts": "Infinity", 
        "timeout" : 10000,                  
        "transports" : ["websocket"],
        withCredentials:true,
            extraHeaders:{
                "my-custom-header": "abcd"
            }
    });

i got this solution from this question

【讨论】：

【解决方案3】：

从 Socket.IO v3 开始，您需要显式启用跨域资源共享 (CORS)。 https://socket.io/docs/v3/handling-cors/

// server-side
const io = require("socket.io")(httpServer, {
  cors: {
    origin: "https://example.com",
    methods: ["GET", "POST"],
    allowedHeaders: ["my-custom-header"],
    credentials: true
  }
});

// client-side
const io = require("socket.io-client");
const socket = io("https://api.example.com", {
  withCredentials: true,
  extraHeaders: {
    "my-custom-header": "abcd"
  }
});

【讨论】：

非常感谢，我尝试了很多方法，我仔细阅读了套接字文档，但不幸的是仍然没有工作。仍然没有连接。