Tag: socket.io

// sending to individual socketid (private message)
io.to(`${socketId}`).emit('hey', 'I just met you');

// WARNING: `socket.to(socket.id).emit()` will NOT work, as it will send to everyone in the room
// named `socket.id` but the sender. Please use the classic `socket.emit()` instead.

References
https://socket.io/docs/emit-cheatsheet/

socket.on('connect', () => {
  // ...
});

// note: you should register event handlers outside of connect,
// so they are not registered again on reconnection
socket.on('myevent', () => {
  // ...
});

References
https://socket.io/docs/client-api/#Event-%E2%80%98connect%E2%80%99

As with broadcasting, the default is all clients from the default namespace (‘/’):

const io = require('socket.io')();  
io.clients((error, clients) => {
      if (error) throw error;
      console.log(clients); // => [6em3d4TJP8Et9EMNAAAA, G5p55dHhGgUnLUctAAAB]
});

Gets a list of client IDs connected to specific namespace (across all nodes if applicable):

const io = require('socket.io')();
io.of('/chat').clients((error, clients) => {
     if (error) throw error;
     console.log(clients); // => [PZDoMHjiu8PYfRiKAAAF, Anw2LatarvGVVXEIAAAD]
});

An example to get all clients in namespace’s room:

const io = require('socket.io')();
io.of('/chat').in('general').clients((error, clients) => {
      if (error) throw error;
      console.log(clients); // => [Anw2LatarvGVVXEIAAAD] 
});

References
https://stackoverflow.com/questions/6563885/socket-io-how-do-i-get-a-list-of-connected-sockets-clients

Server

var io = require('socket.io')(80);

io.on('connection', function (socket) {
  socket.broadcast.emit('user connected');
});

References
https://socket.io/docs/#Broadcasting-messages

var io = require('socket.io')(80);

io.on('connection', function (socket) {
  var tweets = setInterval(function () {
    getBieberTweet(function (tweet) {
      socket.volatile.emit('bieber tweet', tweet);
    });
  }, 100);

  socket.on('disconnect', function () {
    clearInterval(tweets);
  });
});

Refences
https://socket.io/docs/#Sending-volatile-messages

Server

var io = require('socket.io')(80);
var chat = io
  .of('/chat')
  .on('connection', function (socket) {
    socket.emit('a message', {
        that: 'only'
      , '/chat': 'will get'
    });
    chat.emit('a message', {
        everyone: 'in'
      , '/chat': 'will get'
    });
  });

var news = io
  .of('/news')
  .on('connection', function (socket) {
    socket.emit('item', { news: 'item' });
  });

Client

<script>
  var chat = io.connect('http://localhost/chat')
    , news = io.connect('http://localhost/news');
  
  chat.on('connect', function () {
    chat.emit('hi!');
  });
  
  news.on('news', function () {
    news.emit('woot');
  });
</script>

References
https://socket.io/docs/#Restricting-yourself-to-a-namespace

Socket.IO allows you to emit and receive custom events. Besides connect, message and disconnect, you can emit custom events

Server

io.on('connection', function (socket) {

    socket.on("msg1", function (from, msg) {
        console.log('I received a message by ', from, ' saying ', msg);
    });

});

Client

$(document).ready(function () {
    var socket = io.connect('http://localhost:14000');
    socket.emit("msg1", "Mahmood", "Hello");
});

References
https://socket.io/docs/#Sending-and-receiving-events

Server

io.on('connection', function (socket) {
    console.log("Connected : " + socket.client.id);

    socket.on("disconnect", function () {
        console.log("Disconnected : " + socket.client.id);
    })
});

Client

$(document).ready(function () {
    var socket = io.connect('http://localhost:14000');
});

References
https://socket.io/docs/#Sending-and-receiving-events

Server

var express = require('express');
var app = express();
var logger = require('morgan');
var server = require('http').Server(app);
var io = require('socket.io')(server);
app.use(express.static('public'));

app.use(logger('dev'));
server.listen(14000);

app.get('/', function (req, res) {
    res.sendFile(__dirname + '/public/index.html');
});

io.on('connection', function (socket) {
    console.log("Connected : " + socket.client.id);
});

Client

$(document).ready(function () {
    var socket = io.connect('http://localhost:14000');
});

References
https://socket.io/docs/#Using-with-Express