How to create a real-time application with Socket.IO?

Socket.IO is a library that enables real-time, bidirectional and event-based communication between the browser and the server. It consists of a Node.js server and a javascript client library for the browser.

Here’s a basic tutorial on how to create a real-time chat application using Node.js and Socket.IO

1. Installations:

First, you need to install Node.js and npm on your machine if they aren’t already. Then, create a new directory for your application and navigate into it from your terminal. You can install express and socket.io using npm as follows: \`\`\` npm init -y npm install express socket.io \`\`\`

1. Set up an Express Application:

Now, create an `app.js` file in your project directory and set up a basic Express server in it. \`\`\`javascript const express = require(‘express’); const app = express(); const server = require(‘http’).createServer(app); const io = require(‘socket.io’)(server); app.get(‘/’, (req, res) => { res.sendFile(\_\_dirname + ‘/index.html’); }); server.listen(3000, () => { console.log(‘listening on \*:3000’); }); \`\`\`

1. Create the Chatroom:

Create an `index.html` file in your project directory and add the following HTML code to it. \`\`\`html Chatroom

\`\`\` The above code creates an unordered list to hold the messages, an input field to type the messages, and a button to send them.

1. Using Socket.IO:

Now, we have to use Socket.IO to emit events between the client and the server. This will let the app update in real-time. Add the following code inside the `index.html` file. \`\`\`javascript \`\`\` Every time the message form is submitted, the current message in the input field is sent to the server. Add the following code inside the `app.js` file. \`\`\`javascript io.on(‘connection’, (socket) => { console.log(‘a user connected’); socket.on(‘disconnect’, () => { console.log(‘user disconnected’); }); socket.on(‘chat message’, (msg) => { console.log(‘message: ‘ + msg); }); }); \`\`\` The server listens for a connection or disconnection from the client, as well as any `chat message` events.

1. Display the Messages:

Finally, to display the messages for all users, add the following code to both the `app.js` file and the `index.html` file. In `index.html`: \`\`\`javascript socket.on(‘chat message’, function(msg){ $(‘#messages’).append($(’

’).text(msg)); }); \`\`\` In `app.js`: \`\`\`javascript io.emit(‘chat message’, msg); \`\`\`

1. Run your Application:

You have completed your chat application. Now you can start the server and take it for a spin: \`\`\` node app.js \`\`\` Open your browser to `http://localhost:3000` and start chatting!

This tutorial describes the basics of Socket.IO. You can include other features as per your need, such as broadcasting a message to connected users when a user connects or disconnects, adding support for nicknames, separating messages by rooms, and more.