The best place to get started with socket.io is their website. But once you access it you are given this example app demonstrating how to use socket.io.
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');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
If you are fairly new to node, this makes you think that express is needed in order to use socket.io. In the above example they include express to serve the index file which will be client app for your socket server. There is nothing wrong with the above approach but if lets say you don't know express, now you have one more thing to learn before using socket.io.
It would be better if they didn't introduce an additional library in their example. Socket.io has another example using the node http server
var app = require('http').createServer(handler)
var io = require('socket.io')(app);
var fs = require('fs');
app.listen(80);
function handler (req, res) {
fs.readFile(__dirname + '/index.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});
But even this is a little bit too much. I prefer having the server and the client seperate. Therefore this would be my server.
const io = require("socket.io");
const server = io.listen(3000);
server.on("connection", function(socket) {
console.log("user connected");
socket.emit("welcome", "welcome man");
});
And the client would include the socket.io client library and just plain html.
<html>
<head>
<title>Socket io client</title>
<script src="http://localhost:3000/socket.io/socket.io.js"></script>
<script>
var socket = io("http://localhost:3000");
// use your socket
socket.on("welcome", (message) => {
// do something with the message.
})
</script>
</head>
<body>
</body>
</html>
Latest comments (21)
Nice, I have build a Realtime code editor project using socket.io called Code-Sync.
It offers a real-time collaborative code editor featuring unique room generation, syntax highlighting, and auto-suggestions. Users can seamlessly edit, save, and download files while communicating through group chat
I always had this question of Why everybody using express in their examples.
Thank you so much for writing this article. As I searched google, directly found your article. well written and concise.
Thanks for this great tutorial!
When I copy your code and start it, the console throws out this error:
"io.listen is not a function"
Ist this code wrong or am I wrong? I don't know. Can you help me?
do you know any alternative of socket.io for react native apps?
how can I send msg only room member?
"socket.to(roomName).emit('joinRoom2', roomName, name); "is not working
Great. How could it be implemented with https?
What about doing the same thing with https ?
Thanks man. Very nice.
Any one can help to develop a socket IO communication between local server and web server to sync data. Pls send me mail at skumarrcg@gmail.com or whatsapp me at +60173051009
Also, Test/debug the socketio events while you're developing it without writing a single line of frontend code. (no it's not console.log)
It's firecamp.app