Securing a Next.js Application with Keycloak

In this article, we'll be using Keycloak to quickly augment an application with user management and SSO. We will demonstrate the integration by securing a page for logged-in users. This quickly provides a jump-off point to more complex integrations.

Phase Two is a Keycloak as a Service provider enabling SaaS builders to accelerate time-to-market with powerful enterprise features like SSO, identity, and user management features. Phase Two enhances Keycloak through a variety of open-source extentions for modern SaaS use cases. Phase Two supports both hosted and on-premise deployment options.

What is Keycloak?

Keycloak has been a leader in the Identity and Access Management world since its launch almost 8 years ago. It is an open-source offering under the stewardship of Red Hat

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If you just want to skip to the code, visit the Phase Two Next.js example. We also have a plain React example.

TOC

• Keycloak Setup
• Next.js + Keycloak Integration

Setting up a Keycloak Instance

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If you already have a functioning Keycloak instance, you can skip to the next section.

Setting up an OIDC Client

We need to create a OpenID Connect Client in Keycloak for the app to communicate with.

OIDC Config

Adding a Non-Admin User

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It is bad practice to use your Admin user to sign in to an Application.

Since we do not want to use our Admin user for signing into the app we will build, we need to add another non-admin user.

Setting up a Next.js Project

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We will use the Phase Two Next.js example code here, but the logic could easily be applied to any existing application.

This example uses Next.js 13 and splits server and client components accordingly.

1. Clone the Phase Two example repo.
2. Open the Next.js folder within /frameworks/nextjs.
3. Run npm install and then npm run dev. This example leverages NextAuth.js to provide hook and HOC support.
4. NextAuth.js configures an API route that is uses for the Authentication of the Client. It generates the routes automatically for you. These are added to Next.js in the api/auth/[...nextauth]/route.ts file.
5. Open the src/lib/auth.ts file. This is a server only file. We will be updating a few values from the prior section where we set up our OIDC client. Taking the values from the OIDC Client Config section, set those values in the code. While it is recommended to use Environment variables for the secret, for the purpose of this tutorial, paste in the Client secret from the OIDC client creation section for the value of clientSecret

const authServerUrl = "https://euc1.auth.ac/auth/";
const realm = "shared-deployment-001";
const clientId = "reg-example-1";
const clientSecret = "CLIENT_SECRET"; // Paste "Client secret" here. Use Environment variables in prod

Those are used to popluate the AuthOptions config for the KeycloakProvider:

export const AuthOptions: NextAuthOptions = {
  providers: [
    KeycloakProvider({
      clientId,
      clientSecret,
      issuer: `${authServerUrl}realms/${realm}`,
    }),
  ],
};

The config is then provided to the AuthProvider in the /src/app/layout.tsx file. Next.js uses this file to generate an HTML view for this page.

import { NextAuthProvider as AuthProvider } from "./providers";
...
<AuthProvider {...oidcConfig}>
  <App />
</AuthProvider>

At this point, our entire application will be able to access all information and methods needed to perform authentication. View the providers.tsx file for additional information about how the SessionProvider is used. The SessionProvider enables use of Hooks to derive the authenticated state. View user.component.tsx for exactly how the code is authenticating your user. The sections rendering the "Log in" and "Log out" buttons are conditional areas based on the authenticated context. The buttons invoke functions provided by NextAuth.

The logic using the hook to conditionally determine the Authenticated state, can be used to secure routes, components, and more.

1. Open localhost:3000. You will see the Phase Two example landing page. You current state should be "Not authenticated". Click Log In. This will redirect you to your login page.

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Use the non-admin user created in the previous section to sign in.

1. Enter the credentials of the non-admin user you created. Click Submit. You will then be redirected to the application. The Phase Two example landing page now loads your "Authenticated" state, displaying your user's email and their Token.
2. After your first log in, click Log out. Then click Log in again. Notice how this time you will not be redirected to sign in as your state is already in the browser. Neat! If you clear the browser state for that tab, then you will have to be redirected away to sign-in again.

Learning more

Phase Two's enhanced Keycloak provides many ways to quickly control and tweak the log in and user management experience. Our blog has many use cases from customizing login pages, setting up magic links (password-less sign in), and Organization workflows.