Secure Your Next.js App with Authentication
What is Authentication?
Authentication is the process of verifying the identity of a user or device. In the context of web applications, it ensures that users are who they claim to be, preventing unauthorized access to sensitive data and features.
Introducing NextAuth.js
NextAuth.js is a popular library designed specifically for Next.js applications. It provides a complete, open-source authentication solution that supports various providers, including email, Google, GitHub, and more.
Building an Authentication API with NextAuth.js
To get started, you’ll need a basic understanding of React, MongoDB or another database, and how authentication works. Nice-to-haves include prior experience with Next.js and OAuth.
Scaffolding the Application
Use the Next.js CLI to generate a starter project. Choose the default starter app option and create a new project folder.
Creating Environment Variables
Create a .env.local file at the root of your project folder and add the following snippet:
NEXTAUTH_URL=http://localhost:3000
Setting up NextAuth.js
Install the next-auth dependency and create a dynamic API route using pages/api/auth/[...nextauth].js. This file will handle all authentication-related requests.
Implementing Email Sign-in
Add email sign-in functionality by creating a MongoDB database and installing the mongodb driver. Configure the email provider and add database credentials to your .env.local file.
Adding OAuth Providers
NextAuth.js supports various OAuth providers, including Google and GitHub. Create a new project on the developer console, obtain your client ID and secret, and add them to your .env.local file.
Handling Page Redirects
Customize callbacks in your app using Next.js’ redirect callback. This allows you to redirect users to specific pages after sign-in or sign-out.
Common Issues and Solutions
When using GitLab OAuth, ensure that you’ve enabled the read_user and email scopes on the Applications page. Also, verify that your GitLab config matches NextAuth’s config.
Conclusion
In this tutorial, we’ve covered the implementation of email and OAuth authentication using Next.js and NextAuth.js. With these tools, you can securely authenticate users and protect pages on both the client and server sides.