Secure Your Next.js App: Authentication and Authorization with NextAuth.js

Securing Your Next.js Application with Authentication and Authorization

As a developer, protecting your users’ sensitive information is crucial. In this article, we’ll explore how to implement authentication and authorization in a Next.js application using NextAuth.js.

Understanding Authentication and Authorization

Authentication is the process of verifying a user’s identity, while authorization determines what actions a user can perform. In a security system, authentication precedes authorization.

NextAuth.js: A Robust Authentication Solution

NextAuth.js is a feature-packed authentication package for Next.js that supports various authentication providers, including GitHub, Atlassian, and Auth0.

Prerequisites

To follow along with this article, you’ll need:

• The latest or LTS version of Node.js installed on your system
• Basic knowledge of JavaScript, React, and Next.js
• Familiarity with building APIs

Implementing Authentication with NextAuth.js

We’ll implement authentication using two methods: GitHub OAuth and email/password credentials.

GitHub OAuth

First, install NextAuth.js by running npm install next-auth. Create a [...nextauth].js file in the pages/api/auth directory and add the following code:

import NextAuth from 'next-auth';
import Providers from 'next-auth/providers';

export default NextAuth({
providers: [
Providers.GitHub({
clientId: process.env.GITHUB<em>CLIENT</em>ID,
clientSecret: process.env.GITHUB<em>CLIENT</em>SECRET,
}),
],
});
``<code>
Create a</code>.env.local` file in the root directory with your GitHub client ID and client secret.
<h3><strong>Email/Password Credentials</strong></h3>
Create a <code>users.js</code> file in the <code>data</code> directory with an array of users. Create a <code>login.js</code> file in the <code>pages/api</code> directory to handle login requests.

Update the <code>[...nextauth].js</code> file to include the CredentialsProvider:
```javascript
import NextAuth from 'next-auth';
import Providers from 'next-auth/providers';

export default NextAuth({
providers: [
Providers.Credentials({
name: 'Credentials',
credentials: {
username: { label: 'Username', type: 'text' },
password: { label: 'Password', type: 'password' },
},
async authorize(credentials) {
// Add your authentication logic here
},
}),
],
});

Implementing Authorization

Authorization checks whether an authenticated user has permission to view a UI or use a feature. We’ll implement a role-based authorization system.

Create a dashboard.js file in the pages directory that requires admin privileges to view:

import { useSession } from 'next-auth/client';

function Dashboard() {
const { data: session } = useSession();

if (session && session.user.role === 'admin') {
return
<div>Welcome, admin!</div>
;
}

return
<div>You do not have permission to view this page.</div>
;
}

export default Dashboard;

Conclusion

In this article, we explored how to implement authentication and authorization in a Next.js application using NextAuth.js. We implemented authentication using GitHub OAuth and email/password credentials and authorization using a role-based system.