WebSocket

1. 什么是WebSocket

有状态的持久连接
服务端主动推送消息
用WebSocket发送信息比HTTP延迟低

一个🌰

服务端代码客户端代码

const { WebSocketServer } = require('ws');
    
const wss = new WebSocketServer({ port: 8080 });

wss.on('connection', function connection(ws) {
    ws.on('message', function incoming(message) {
        console.log('received: %s', message);
    });

    ws.send('something');
});

const { WebSocketServer } = require('ws');
    
const wss = new WebSocketServer({ port: 8080 });

wss.on('connection', function connection(ws) {
    ws.on('message', function incoming(message) {
        console.log('received: %s', message);
    });

    ws.send('something');
});

const WebSocket = require('ws');

const ws = new WebSocket('ws://localhost:8080');

ws.on('open', function open() {
   // 当建立连接的时候，向客户端发送一条信息
    ws.send('something');
});

ws.on('message', function message(data) {
   // 当收到来自服务端的消息的时候，打印出来
    console.log(`received: ${data}`);
});

const WebSocket = require('ws');

const ws = new WebSocket('ws://localhost:8080');

ws.on('open', function open() {
   // 当建立连接的时候，向客户端发送一条信息
    ws.send('something');
});

ws.on('message', function message(data) {
   // 当收到来自服务端的消息的时候，打印出来
    console.log(`received: ${data}`);
});

客户端在HTTP请求头增加：Connection: Upgrade+Upgrade: Websocket

服务端在接受请求后，返回101 Switching Protocols响应

WebSocket ​

1. 什么是WebSocket ​

WebSocket

1. 什么是WebSocket