Creating Websocket servers and clients in Nodejs

1. Websocket server example

const WebSocketServer = require('ws');
const wss = new WebSocketServer.Server({ port: 8111 })

wss.on("connection", (ws,r) => {
  ws.on("message", data => {
    ws.send('You sent me: ' + data);
  });

  ws.on("close", () => { });
  ws.onerror = function () { };
});

• require('ws') - import ws lib to create websocket server,
• new WebSocketServer.Server - create and launch websocket server with params,
• port: - port to listen on (in our case all network interfaces are going to be listened),
• wss.on("connection" - what to do when someone connects to our server,
• ws.on("message" - what to do when we've received a message from client,
• ws.send( - send a message to client,
• ws.on("close" - what to do when client closes connection,
• ws.onerror - set custom error handler.

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2. Websocket client example

let ws = require('websocket');
let wsc = new ws.client;

wsc.on('connect', function(connection) {
  connection.sendUTF('Hello');

  connection.on('message', function(message) {
    console.log("Received: " + message.utf8Data);
    // connection.close();
  });
});

wsc.connect('ws://echoof.me:8111/');

• require('websocket') - import websocket lib to create websocket client,
• new ws.client - create new websocket client object,
• wsc.on('connect' - specify what to do when client gets connected to websocket server,
• connection.sendUTF - send message to server,
• connection.on('message' - specify what to do when client received message from server,
• connection.close() - close connection (and exit),
• wsc.connect - connect to websocket server,
• echoof.me:8111 - public echo websocket server.

Open original or edit on Github.