How to create a real-time chat in Node.js by using Socket.IO

In this tutorial I'm going to show you an easy way to create a real-time chat in Node.js by using Socket.IO. I will follow the Socket.IO's documentation to create the chat.

First I will create a new directory with three files:

  • index.js
  • package.json
  • index.html

In the package.json file I will add this code:


{
"name": "socket-chat-example",
"version": "0.0.1",
"description": "my first socket.io app",
"dependencies": {}
}

In the index.html I will add this code:

<!doctype html>
<html>
<head>
<title>Socket.IO chat</title>
<style>
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font: 13px Helvetica, Arial; }
form { background: #000; padding: 3px; position: fixed; bottom: 0; width: 100%; }
form input { border: 0; padding: 10px; width: 90%; margin-right: .5%; }
form button { width: 9%; background: rgb(130, 224, 255); border: none; padding: 10px; }
#messages { list-style-type: none; margin: 0; padding: 0; }
#messages li { padding: 5px 10px; }
#messages li:nth-child(odd) { background: #eee; }
</style>
</head>
<body>
<ul id="messages"></ul>
<form action="">
<input id="m" autocomplete="off" /><button>Send</button>
</form>
<script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>
<script src="http://code.jquery.com/jquery-1.11.1.js"></script>
<script>
var socket = io("http://localhost:3000"); // this code will connect to the host that serves the page.
$('form').submit(function(){ // this function will run after form submit
socket.emit('chat message', $('#m').val());
$('#m').val('');
return false;
});
socket.on('chat message', function(msg){ // this code will display messages in the chat
$('#messages').append($('<li>').text(msg));
});
</script>
</body>
</html>

In the file index.js, I will add this code:

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

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

io.on('connection', function(socket){
console.log('a user connected');
});

io.on('connection', function(socket){
socket.on('chat message', function(msg){
io.emit('chat message', msg);
});
});

http.listen(3000, function(){
console.log('listening on *:3000');
});

Video tutorial:









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