H11: Vestlusruum serveri ja klientrakenduse vahel

VS koodis loodi kaks faili index.js ja index.html

const http =  require("http")
const fs = require("fs")
const ws = new require("ws")
 
const wss = new ws.Server({noServer: true});
 
function accept(req, res) {
    if(req.url === '/ws' && req.headers.upgrade 
        && req.headers.upgrade.toLowerCase() === 'websocket'
        && req.headers.connection.match(/\bupgrade\b/i)) {
        wss.handleUpgrade(req, req.socket, Buffer.alloc(0), onSocketConnect);
    } else if (req.url === '/') {
        fs.createReadStream('./index.html').pipe(res);
    } else {
        res.writeHead(404);
        res.end();
    }
}
 
const clients = new Set();
 
function onSocketConnect(ws) {
    clients.add(ws);
    ws.on('message', function(message) {
        message = message.slice(0,50); //max length will be 50
        for(let client of clients) {client.send(message);}
    });
    ws.on('close', function() {
        log('connection closed');
        clients.delete(ws);
    });
}
 
let log;
 
if (!module["parent"]) {
    log = console.log;
    http.createServer(accept).listen(8080);
} else {
    //to embed into javascript.info
    log = function() {};
    // log = console.log
    exports.accept = accept;
}

index.html

<!doctype html>
<form name="publish">
    <input type="text" name="message" maxlength="50"/>
    <input type="submit" value="Send"/>
</form>
  
<div id="messages"></div>
  
<script>
    let url = location.host == 'localhost' ?
        'ws://localhost:8080/ws' : location.host == 'javascript.local' ?
            `ws://javascript.local/article/websocket/chat/ws` : // dev integration with local site
            `wss://javascript.info/article/websocket/chat/ws`; // prod integration with javascript.info
    //создаем объект с вебсокетом
    let socket = new WebSocket(url);
  
    // отправляем сообщение на форму
    document.forms.publish.onsubmit = function() {
        let outgoingMessage = this.message.value;
  
        socket.send(outgoingMessage);
        return false;
    };
  
    // обрабатываем входящие сообщения
    socket.onmessage = function(event) {
        let incomingMessage = event.data;
        showMessage(incomingMessage);
    };
    //если пользователь закрыт сокет, то пишем об этом в консоли
    socket.onclose = event => console.log(`Closed ${event.code}`);
  
    // показываем сообщения в div#messages
    function showMessage(message) {
        let messageElem = document.createElement('div');
        messageElem.textContent = message;
        document.getElementById('messages').prepend(messageElem);
    }
</script>