Express.js Tutorial – Basic to Advance

Welcome to our tutorial on Express.js! Express.js is a powerful and lightweight web application framework for Node.js that provides a robust set of features to develop web applications quickly and easily. In this tutorial, we will cover everything you need to know to get started with Express.js, from the basics to more advanced topics.

How To Use JSON Web Tokens (JWTs) in Express.js

JSON Web Tokens (JWTs) are a popular method for securely transmitting information between parties as a JSON object. They are commonly used for authentication and authorization in web applications. In Express.js, we can easily implement JWTs to secure our APIs and protect sensitive information.

Step 1: Install the required packages

First, we need to install the necessary packages for working with JWTs in Express.js. You can do this by running the following command in your terminal:

npm install jsonwebtoken

Step 2: Create middleware for JWT authentication

Next, we need to create middleware that will verify JWTs sent by clients in our Express.js application. This middleware will check the token against a secret key and decode the payload to extract information.

    const jwt = require('jsonwebtoken');

    function verifyToken(req, res, next) {
        const token = req.headers['authorization'];
        
        if (!token) {
            return res.status(403).json({ message: 'No token provided' });
        }
        
        jwt.verify(token, 'secretkey', (err, decoded) => {
            if (err) {
                return res.status(401).json({ message: 'Unauthorized' });
            }
            
            req.user = decoded;
            next();
        });
    }

    module.exports = verifyToken;
    

Step 3: Use JWT middleware in your routes

Now that we have created our JWT authentication middleware, we can use it in our routes to protect them from unauthorized access. Simply include the middleware function before the route handler that needs to be protected.

    const express = require('express');
    const verifyToken = require('./verifyToken');

    const app = express();

    app.get('/protected-route', verifyToken, (req, res) => {
        res.json({ message: 'This is a protected route' });
    });

    app.listen(3000, () => {
        console.log('Server is running on port 3000');
    });
    

And that’s it! You have now successfully implemented JWT authentication in your Express.js application. You can further customize the middleware and handle different scenarios based on your requirements.

Thank you for following our Express.js tutorial – from basic to advance. We hope you found this information helpful in building secure and efficient web applications with Express.js. Happy coding!