Next.js has recently released a stable version of App Router enriched with in-built support for layouts, templates, routing, loading, and error handling.

The current version of Next-Auth documentation is published with examples of the Page Router of Next.js. This document share approach to setting up Next.js with the Next-Auth App Router.

What is covered in this document?

Setup of Next.js app with app router.
Install Next-Auth.
Configuration of Github Provider.
Add Handler for Next-Auth
Sign in and Sign out using next-auth.
Use session in the Server Components
Use of session in the Client Components.

Set up the Next.js app with the App router.

Follow this document to create a basic next.js app with an app router.

Next.js app with App router.

Install Next-Auth

npm install next-auth

Configuration of Github Provider

Create a GitHub App first, providing you a client Id and Secret. Add a file auth.js in the lib folder.

Note: Generate a secret to add as NEXTAUTH_SECRET, it must be added in the auth options.

openssl rand -base64 32

// output
// mQ46qpFwfE1BHuqMC+qlm19qBAD9fVPgh28werwe3ASFlAfnKjM=

next. config.js

/** @type {import('next').NextConfig} */
const nextConfig = {
  images: {
    remotePatterns: [
      {
        protocol: 'https',
        hostname: 'i.imgur.com',
      },
    ],
  },
  env: {
    GITHUB_APP_CLIENT_ID: '919b87qa4sdfs1qdc44f53baf9',
    GITHUB_APP_CLIENT_SECRET: '2aeq98df3f8cwqerc2d03a8360e993c115ba8d5f71de9',
    NEXTAUTH_SECRET: 'mQ46qpFwfE1BHuqMC+qlm19qBAD9fVPgh28werwe3ASFlAfnKjM=',
  },
};

module.exports = nextConfig;

import { NextAuthOptions } from 'next-auth';
import GithubProvider from 'next-auth/providers/github';
export const authOptions: NextAuthOptions = {
  // Secret for Next-auth, without this JWT encryption/decryption won't work
  secret: process.env.NEXTAUTH_SECRET,

  // Configure one or more authentication providers
  providers: [
    GithubProvider({
      clientId: process.env.GITHUB_APP_CLIENT_ID as string,
      clientSecret: process.env.GITHUB_APP_CLIENT_SECRET as string,
    }),
  ],
};

Add Handler for Next-Auth

Create a file route.js in the folder /app/auth/[…nextauth]

Next-Auth Handler

import NextAuth from 'next-auth';
import { authOptions } from '@/app/lib/auth';

const handler = NextAuth(authOptions);
export { handler as GET, handler as POST };

Sign in and Sign out using next-auth

All requests to any of these paths /api/auth/* (signIn, callback, signOut, etc.) will be handled by NextAuth.js.

Once you click the button, log in, and authorize the app, it will get a cookie in the session.

Next-Auth default Sign in page
After successful sign-in.

Next-Auth token

Sign Out

use this link /api/auth/signout to sign out.

Session in API routes.

API route handlers are considered server components. It can be a static or dynamic handler but these are always on the server side.

import { authOptions } from '@/app/lib/auth';
import { getServerSession } from 'next-auth';
import { NextResponse } from 'next/server';

export async function GET(request: Request) {
  const session = await getServerSession(authOptions);
  console.log(session);
  return NextResponse.json({
    id: 1,
  });
}

Output

{
  user: {
    name: 'Rohit Kumar Khatri',
    email: 'er.rohitkumar@outlook.com',
    image: 'https://avatars.githubusercontent.com/u/34018015?v=4'
  }
}

Session in Server Components

It is also similar in all server components. Use the same function as mentioned above.

await getServerSession(authOptions);

Session in Client Components

First, add Session Provider in the Root Layout

'use client';

import { SessionProvider } from 'next-auth/react';
import { ReactNode } from 'react';

export default function NextAuthProvider({
  children,
}: {
  children: ReactNode;
}) {
  return <SessionProvider>{children}</SessionProvider>;
}

import { useSelectedLayoutSegments } from 'next/navigation';
import './globals.css';
import { Inter } from 'next/font/google';
import Footer from '@/app/components/Footer';
import Navbar from '@/app/components/Navbar';
import NextAuthProvider from '@/app/context/NextAuthProvider';
import { ReactNode } from 'react';
const inter = Inter({ subsets: ['latin'] });

export default function RootLayout({ children }: { children: ReactNode }) {
  return (
    <html lang="en">
      <body className={`inter.className`}>
        <NextAuthProvider>
          <div className="w-10/12 m-auto text-center bg-white flex flex-col min-h-screen">
            <div>
              <Navbar />
            </div>
            <div className="grow">{children}</div>
            <Footer />
          </div>
        </NextAuthProvider>
      </body>
    </html>
  );
}

Now use session in any client component.

'use client';

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

export default function ClientComponent() {
  const { data: session, status } = useSession();
  return (
    <div>
      ClientComponent {status}{' '}
      {status === 'authenticated' && session.user?.name}
    </div>
  );
}

Next-Auth in App Router of Next.js