nextjs authentication middleware with NextAuth.js

Next.js authentication middleware with NextAuth.js is a powerful combination for securing your applications. NextAuth.js provides a simple and scalable way to handle authentication with popular providers like Google, Facebook, and GitHub.

NextAuth.js can be easily integrated into Next.js using the built-in API routes feature, allowing you to handle authentication logic in a centralized manner. This makes it easier to manage and maintain your application's security.

With NextAuth.js, you can use the `useSession` hook to access the current user's session data, making it easy to authenticate and authorize users in your application. This hook is particularly useful for protecting routes and pages that require authentication.

NextAuth.js also provides a `session` object that can be used to store and retrieve user data, making it easy to implement features like user profiles and account management.

Worth a look: Next Js Protected Routes

To set up your Next.js project for authentication, you'll need to configure environment variables. This involves creating a .env.local file in the root of your project and adding specific variables.

Start by creating a new file called .env.local in the root of your project. You can find the required variables on your Kinde Settings > Applications > [Your app] > View details page.

Here are the variables you'll need to add to your .env.local file:

Make sure to replace the example information with your own and adjust the URLs as needed to match your project's setup.

Additionally, you may need to set up environment variables for other services, such as Supabase. For example, you'll need to add NEXT_PUBLIC_SUPABASE_URL and NEXT_PUBLIC_SUPABASE_ANON_KEY to your .env.local file.

Lastly, don't forget to generate a secret key for NextAuth.js using the command `npx next-auth demo` and add it to your .env.local file as NEXTAUTH_SECRET.

To set up NextAuth.js, you'll need to create a new file called [...nextauth].js in the pages/api/auth directory of your project and add the following code. This file defines your NextAuth.js configuration, including the authentication providers you want to use.

You can specify multiple providers in the providers array, such as credentials, magic links, or social media logins. To generate a secret key for NextAuth.js, you can use the command openssl rand -base64 32. Store this key in a .env.local file in the root directory of your project.

NextAuth.js requires a secret key to sign and encrypt tokens. You can use a package like dotenv to load environment variables from a .env file. Alternatively, you can use a tool like direnv to manage your environment variables. Create a .envrc file in the root directory of your project and add the environment variables.

Here are the steps to set up NextAuth.js:

1. Create a new file called [...nextauth].js in the pages/api/auth directory of your project.

2. Add the following code to the [...nextauth].js file:

3. Specify the authentication providers you want to use in the providers array.

4. Generate a secret key using the command openssl rand -base64 32.

5. Store the secret key in a .env.local file or use a package like dotenv or direnv to manage your environment variables.

By following these steps, you'll be able to set up NextAuth.js and configure it to use the authentication providers you need.

Additional reading: Why Next Js

Authentication providers are a crucial part of Next.js authentication middleware, allowing users to sign in and access protected routes and pages. You can choose from various authentication providers, including Email and Password (Credentials), Magic Links via Email, and Social Media Logins (e.g., Twitter, Facebook, Google).

NextAuth.js supports a variety of authentication providers, making it easy to implement different login methods for your users. Some popular options include Email and Password (Credentials), Magic Links via Email, and Social Media Logins (e.g., Twitter, Facebook, Google).

To add social login options to your Next.js app, you can use the respective providers from next-auth/providers. For example, to add the Google provider, you can install the necessary package and update your pages/api/auth/[...nextauth].js file to include the Google provider.

Here are some popular authentication providers you can use with NextAuth.js:

To add a credentials provider to your already existing provider, update your pages/api/auth/[...nextauth].js file with the following code. The authorize callback function is defined for CredentialsProvider, which is responsible for authenticating users based on the provided credentials that is email and password.

You can also use the EmailProvider for magic links, which involves adding it to the providers array in your authOptions configuration. The from option specifies the sender's email address, maxAge sets the expiration time for the magic link (2 hours in this case), and sendVerificationRequest is a custom function that sends the login email.

To implement magic links via email, you'll need to create a login page where users can enter their email address to receive the magic link. The signIn function from next-auth/react is called with the “email” provider and the entered email address. The callbackUrl parameter specifies the page to redirect to after successful authentication.

Route protection is crucial for Next.js apps, especially when using authentication middleware. You can protect routes with NextAuth.js middleware by creating a new file named middleware.js in the root directory of your Next.js project.

The withAuth middleware is used to protect routes, and the authorized callback checks if a valid token exists, indicating that the user is authenticated. In Server Components, you can get the Kinde Auth data by using the getKindeServerSession helper, while in Client Components, you can use the useKindeBrowserClient helper.

To protect routes, you can also use the withAuth helper with a middleware callback function, which has access to the req.kindeAuth object that exposes the token and user data. The middleware options include isReturnToCurrentPage, loginPage, publicPaths, and isAuthorized, which can be used to configure the middleware's functionality.

On a similar theme: Nextjs Client Session Token

Route and Page Protection is a crucial aspect of securing your application. You can protect routes with Kinde Auth data by using the getKindeServerSession helper in Server Components or the useKindeBrowserClient helper in Client Components.

To automatically send the user to the sign in screen, you can check if the user is authenticated and handle it accordingly. If you want the user to be redirected back to that route after signing in, you can set post_login_redirect_url in the search params of the redirect.

You can also protect routes using Next.js middleware. The withAuth helper will protect routes covered by the matcher, redirecting the user to login if they're not authenticated. Once logged in, they'll be redirected back to the protected page.

The withAuth helper can also be used with a middleware callback function, which has access to the req.kindeAuth object that exposes the token and user data. This allows for more flexibility in handling authentication.

For your interest: Nextjs Middleware Matcher

Middleware options are available to configure the functionality, including isReturnToCurrentPage, loginPage, publicPaths, and isAuthorized. These options can be passed into the middleware function to customize its behavior.

Here are the middleware options with a brief description:

By using these options, you can fine-tune the behavior of the withAuth middleware to suit your application's needs.

To add Vercel's dynamically generated URLs, you can either use their API to add them securely on the fly or use wildcard URLs. However, wildcard URLs are not as secure as explicitly adding the URL to the allowlist via API.

Make sure to add the following to your next.config.js file to ensure Vercel uses its generated preview URLs to populate the three Kinde variables.

To access user session data in your Next.js application, you can use the useSession hook from next-auth/react. This hook allows you to conditionally render content based on the user's authentication status.

You can wrap your entire application with the SessionProvider component, making the authentication session available throughout your Next.js app. This configuration ensures that the user's session is available throughout your application, allowing you to easily access authentication state in all your components.

To access the user's session information, you can use the useSession hook in your pages or components. This hook provides access to the user's session data, which you can use to conditionally render content or show appropriate messages.

You can also fetch the user session on the server-side using the unstable_getServerSession function from next-auth/next. This function is used in the getServerSideProps function to fetch the user session on the server-side.

Here are some guidelines for choosing between client-side and server-side session fetching:

By configuring the session expiration and refresh token behavior in your NextAuth.js configuration, you can handle session expiration and refresh tokens automatically. This ensures that users are logged out when their session expires and prompts them to re-authenticate when necessary.

To handle session expiration and refresh tokens, you can configure the session and jwt options in your NextAuth.js configuration. For example, you can set the session to expire after 30 days (maxAge) and update every 24 hours (updateAge) to extend its validity.

Here's an interesting read: Nextjs Session

NextAuth.js can handle user sessions using cookies without requiring a database, but this approach has its limitations. It's essential to integrate a database to store and manage user information beyond just the session.

You'll typically want to store user details, such as email addresses and hashed passwords, in a database to authenticate users securely and persist their information across sessions. This is crucial for storing user profiles and preferences, as well as implementing specific authentication flows like magic links or email verification.

Some common reasons to integrate a database include storing user details, user profiles and preferences, authentication flows, and scalability and performance. NextAuth.js supports a wide variety of databases through its adapter system, giving you the flexibility to choose the one that best suits your application's requirements.

Here are some popular database providers supported by NextAuth.js, including Prisma, PostgreSQL, SQLite, and MongoDB. Each of these databases has its own strengths and weaknesses, and choosing the right one will depend on your specific needs and tech stack.

NextAuth.js's adapter system makes it easy to switch between different databases, giving you the flexibility to choose the one that best fits your application's requirements. By integrating a database with NextAuth.js, you can persist user information, implement specific authentication flows, and scale your application effectively.

Additional reading: Next Js Database

Role-Based Access Control is a crucial aspect of Next.js authentication middleware. It allows you to restrict access to specific parts of your app based on a user's role.

You can implement role-based access by checking the user's role in your middleware file. This can be done by retrieving the user's role from the cookie, as shown in Example 6. Middleware functions can intercept and manipulate incoming HTTP requests and outgoing responses, making them ideal for authentication and authorization tasks.

To restrict access to the admin_dashboard route, you can use individual checks, as demonstrated in Example 6. This involves matching routes individually or collectively, allowing you to control access to specific parts of your app.

Middleware functions can be used to authorize users and control their access to specific parts of your app. They can also be used to log in, and when you click on the admin, it should show Permission denied because we set the role to member.

Worth a look: Nextjs Middleware Firebase Auth

In Next.js, middleware refers to a function that runs before handling a request. It allows you to intercept and manipulate incoming HTTP requests and outgoing responses. Middleware functions are commonly used for authentication, authorization, logging, error handling, and data parsing.

To implement role-based authentication, you need to update the user's properties in the database to include the user's role. This can be done by setting the token.role = "member" to test our code, as shown in Example 5.

For your interest: Nextjs 13 Middleware

To implement authentication in Next.js, you can use NextAuth.js, an open-source library designed specifically for authentication in Next.js applications. NextAuth.js offers a secure and flexible way to handle user logins, signups, and authorization within your project.

To start using NextAuth.js, you need to create a Next.js project by running a command in your terminal. After that, install NextAuth.js by running another command in your terminal.

Authentication is verifying a user's identity, checking if a user is who they claim to be. A typical example of authentication is using an ID to buy age-restricted items in a store.