Node.js使用Socket.io实现跨域WebSocket即时通讯

const socket = require("socket.io");
const http = require('http');
// 创建服务
const server = http.createServer((req,res)=>{
    // 允许所有跨域请求
    res.setHeader('Access-Control-Allow-Origin', '*');
    req.writeHead(200,{'Content-Type':'text/html'})
    res.end('')
}).listen(8001)
let pad = null,pc = null , padReady = false , pcReady = false;
// 连接socket.io
socket.listen(server).on('connection',(conn)=>{
    conn.on('message',(str)=>{
        if(str==="Pad"){
            pad = conn;
            padReady = true;
            conn.send('连接成功');
        }
        if(str==="PC"){
            pc = conn;
            pcReady = true;
        }
        if(padReady&&pcReady){
            if(str==='PC') str='我是PC界面'
            pc.send(str);
        }
    })
    conn.on("disconnection",(code, reason) => {
        console.log("关闭连接")
    });
})

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .kuang {
            text-align: center;
            margin-top: 200px;
        }
        #mess {
            text-align: center
        }
        .value {
            width: 200px;
            height: 200px;
            border: 1px solid;
            text-align: center;
            line-height: 200px;
            display: inline-block;
        }
    </style>
</head>
<body>
    <div id="mess">正在连接...</div>
    <div class="kuang">
        <div class="value" id="value1">aaaaaaa</div>
        <div class="value" id="value2">bbbbbbb</div>
        <div class="value" id="value3">ccccccc</div>
    </div>
    <script src="./js/socket.io.js"></script>
    <script>
        // 跨域地址
        const socket = io('192.168.1.115:8001')
        socket.on('connect', () => {
            // 连接成功
            socket.send('Pad')
            // 监听连接
            socket.on('message', (msg) => {
                document.getElementById('mess').innerHTML=msg
                // console.log(msg)
            })
            // 关闭连接
            socket.on('disconnect', () => {
            })
        })
        document.querySelector(".kuang").onclick = (e)=> {
           socket.send(e.target.innerHTML);
        }
    </script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .kuang {
            text-align: center;
            margin-top: 200px;
        }
        #mess {
            text-align: center
        }
    </style>
</head>
<body>
    <div id="mess"></div>
    <script src="./js/socket.io.js"></script>
    <script>
        var mess = document.getElementById("mess");
        // 跨域地址
        // TODO: 这里注意一下 不能写127.0.0.1 或者localhost 不然其他客户端访问不到
        const socket = io('192.168.1.115:8001')
        socket.on('connect', () => {
            // 连接成功
            socket.send('PC')
            // 监听连接
            socket.on('message', (msg) => {
                mess.innerHTML = msg
                // console.log(msg)
            })
            // 关闭连接
            socket.on('disconnect', () => {
            })
        })
    </script>
</body>
</html>