Role-based access control

There are two ways to add role-based access control (RBAC) to your application with Auth.js, based on the session strategy you choose. Let’s see an example for each of these.

Getting the role

Start by adding a profile() callback to the providers’ config to determine the user role:

./auth.ts

import NextAuth from "next-auth"
import Google from "next-auth/providers/google"
 
export const { handlers, auth } = NextAuth({
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      },
    })
  ],
})

./src/auth.ts

import SvelteKitAuth from "@auth/sveltekit"
import Google from "@auth/sveltekit/providers/google"
 
export const { handle } = SvelteKitAuth({
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      },
    })
  ],
})

💡

Determining the users role is your responsibility, you can either add your own logic or if your provider returns a role you can use that instead.

Persisting the role

Persisting the role will be different depending on the session strategy you’re using. If you don’t know which session strategy you’re using, then most likely you’re using JWT (the default one).

With JWT

When you don’t have a database configured, the role will be persisted in a cookie, by using the jwt() callback. On sign-in, the role property is exposed from the profile callback on the user object. Persist the user.role value by assigning it to token.role. That’s it!

If you also want to use the role on the client, you can expose it via the session callback.

./auth.ts

import NextAuth from "next-auth"
import Google from "next-auth/providers/google"
 
export const { handlers, auth } = NextAuth({
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      },
    })
  ],
  callbacks: {
    jwt({ token, user }) {
      if(user) token.role = user.role
      return token
    },
    session({ session, token }) {
      session.user.role = token.role
      return session
    }
  }
})

./src/auth.ts

import SvelteKitAuth from "@auth/sveltekit"
import Google from "@auth/sveltekit/providers/google"
 
export const { handle } = SvelteKitAuth({
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      },
    })
  ],
  callbacks: {
    jwt({ token, user }) {
      if(user) token.role = user.role
      return token
    },
    session({ session, token }) {
      session.user.role = token.role
      return session
    }
  }
})

With this strategy, if you want to update the role, the user needs to be forced to sign in again.

With Database

When you have a database, you can save the user role on the User model. The below example is showing you how to do this with Prisma, but the idea is the same for all adapters.

First, add a role column to the User model.

/prisma/schema.prisma

model User {
  id            String    @id @default(cuid())
  name          String?
  email         String?   @unique
  emailVerified DateTime?
  image         String?
  role          String?  // New column
  accounts      Account[]
  sessions      Session[]
}

The profile() callback’s return value is used to create users in the database. That’s it! Your newly created users will now have an assigned role.

If you also want to use the role on the client, you can expose it via the session callback.

./auth.ts

import NextAuth from "next-auth"
import Google from "next-auth/providers/google"
import prisma from "lib/prisma"
 
export const { handlers, auth } = NextAuth({
  adapter: PrismaAdapter(prisma),
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      }
    })
  ],
  callbacks: {
    session({ session, user }) {
      session.user.role = user.role
      return session
    }
  }
})

./src/auth.ts

import SvelteKitAuth from "@auth/sveltekit"
import Google from "@auth/sveltekit/providers/google"
import prisma from "lib/prisma"
 
export const { handle, auth } = SvelteKitAuth({
  adapter: PrismaAdapter(prisma),
  providers: [
    Google({
      profile(profile) {
        return { role: profile.role ?? "user", ... }
      }
      ...
    })
  ],
  callbacks: {
    session({ session, user }) {
      session.user.role = user.role
      return session
    }
  }
})

src/hooks.server.ts

export { handle } from "./auth"

It is up to you how you want to manage to update the roles, either through direct database access or building your role update API.

Using the role

If you want to use the role in the client, for both cases above, when using the useSession hook, session.user.role will have the required role if you exposed it via the session callback. You can use this to render a different UI for different users.

./app/admin/page.tsx

import { useSession } from "next-auth/react";
 
export default function Page() {
  const session = await useSession();
 
  if (session?.user.role === "admin") {
    return <p>You are an admin, welcome!</p>;
  }
 
  return <p>You are not authorized to view this page!</p>;
}

./routes/+page.server.ts

import { redirect } from "@sveltejs/kit"
 
export const load: PageServerLoad = async (event) => {
  const session = await event.locals.auth()
 
  if (!session && event.url.pathname !== "/login") {
    const fromUrl = event.url.pathname + event.url.search
    redirect(307, `/login?redirectTo=${encodeURIComponent(fromUrl)}`)
  }
 
  return {
    session,
  }
}

💡

When using Next.js and JWT, you can alternatively also use Middleware to redirect the user based on their role, even before rendering the page.

Resources

Restricting users accessing to the app Configuring GitHub for OAuth

Role-based access control

Getting the role

Persisting the role

With JWT

With Database

Using the role

Resources

About Auth.js

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Acknowledgements