Socket.IO Server with Node.JS

Socket.IO Server with Node.js

Before you start it we have Part 1 here. Please read that as well for basic concepts of sockets and communication.

We will do the following in this guide:

• Install and Set the Node.js application
• Install required dependencies
• Make a simple connecting server with Socket.IO

Node Installation:

To set up a server using Node.js, make sure that you have the latest version of Node.js installed on your computer. I will be using the Windows Operating system.

After completing the installation process, please verify the installation. Open the command terminal to verify and run the following command:

node -v

If you get the installed version from the command we are good to go. Otherwise, revisit the installation process.

NODE SERVER-SIDE SETUP:

Create a new directory for your project and navigate to it in your terminal or command prompt.

mkdir test-project

cd test-proect

npm init -y

Your console may look something like this:

This will set up the base for Node.js application inside your workspace with the name “test-project”.

Installing Dependencies

We will use 2 actually famous packages of node.js from npm library of packages.

• Express
• Socket.IO

To install these packages type the following commands in vscode terminal.

npm install express

npm install socket.io

Now the package.json file will be something like this.

Let's Make a simple server

Create a new JavaScript file in your project directory called “server.js”.

Open server.js in visual code and add the following code to set up a basic Node.js server:

const express = require('express')
const app = express();
const http = require('http').createServer(app);

http.listen(3000, () => 
? console.log('Server listening on port 3000');
});        

This will create an Express app and start a Node.js server on port 3000.

Add the following code to server.js to set up Socket.io:

const io = require('socket.io')(http);

io.on('connection', (socket) => 
? console.log('a user connected');

? socket.on('disconnect', () => {
? ? console.log('user disconnected');
? });

});        

This will create a new Socket.io instance that listens for connections on the Node.js server. When a user connects, the server will log a message to the console.

Run the following command in your terminal to start the Node.js server:

node server.js

This will start the server on port 3000.

Let's create a custom message to receive from the client and do something about it.

Update the "io.on.........." section like this:

io.on('connection', (socket) => 
? ? console.log('a user connected');


? ? socket.on('message', (data) => {
? ? ? ? 
? ? ? //Client have sent some message please do something about it. ?
? ? ? ? console.log('Message from client', data);
? ? ? //sending response to client side
? ? ? ? socket.emit('message', {date: new Date().getTime(), data: data});
? ? ? 
? ? ? });


? ? socket.on('disconnect', () => {
? ? ? console.log('user disconnected');
? ? });
});        

Congressssss we have our server ready to listen to a client.

If you have something in mind about sockets and communication please visit my previous article here.