web

Next.js

Next.js

In this quickstart, you are going to build an application with Next.js and integrate it with FusionAuth. You’ll be building it for ChangeBank, a global leader in converting dollars into coins. It’ll have areas reserved for users who have logged in as well as public facing sections.

The Docker Compose file and source code for a complete application are available at https://github.com/FusionAuth/fusionauth-quickstart-javascript-nextjs-web.

Prerequisites

  • Node LTS
  • Docker: The quickest way to stand up FusionAuth. (There are other ways).
  • git: Not required but recommended if you want to track your changes.

General Architecture

While this sample application doesn't have login functionality without FusionAuth, a more typical integration will replace an existing login system with FusionAuth.

In that case, the system might look like this before FusionAuth is introduced.

UserApplicationView HomepageClick Login LinkShow Login FormFill Out and Submit Login FormAuthenticates UserDisplay User's Account or OtherInfoUserApplication

Request flow during login before FusionAuth

The login flow will look like this after FusionAuth is introduced.

UserApplicationFusionAuthView HomepageClick Login Link (to FusionAuth)View Login FormShow Login FormFill Out and Submit Login FormAuthenticates UserGo to Redirect URIRequest the Redirect URIIs User Authenticated?User is AuthenticatedDisplay User's Account or OtherInfoUserApplicationFusionAuth

Request flow during login after FusionAuth

In general, you are introducing FusionAuth in order to normalize and consolidate user data. This helps make sure it is consistent and up-to-date as well as offloading your login security and functionality to FusionAuth.

Getting Started

In this section, you’ll get FusionAuth up and running, and configured with the ChangeBank application.

Clone The Code

First off, grab the code from the repository and change into that directory.

git clone https://github.com/FusionAuth/fusionauth-quickstart-javascript-nextjs-web.git
cd fusionauth-quickstart-javascript-nextjs-web

Run FusionAuth Via Docker

You'll find a Docker Compose file (docker-compose.yml) and an environment variables configuration file (.env) in the root directory of the repo.

Assuming you have Docker installed, you can stand up FusionAuth on your machine with the following.

docker compose up -d

Here you are using a bootstrapping feature of FusionAuth called Kickstart. When FusionAuth comes up for the first time, it will look at the kickstart/kickstart.json file and configure FusionAuth to your specified state.

If you ever want to reset the FusionAuth application, you need to delete the volumes created by Docker Compose by executing docker compose down -v, then re-run docker compose up -d.

FusionAuth will be initially configured with these settings:

  • Your client Id is e9fdb985-9173-4e01-9d73-ac2d60d1dc8e.
  • Your client secret is super-secret-secret-that-should-be-regenerated-for-production.
  • Your example username is richard@example.com and the password is password.
  • Your admin username is admin@example.com and the password is password.
  • The base URL of FusionAuth is http://localhost:9011/.

You can log in to the FusionAuth admin UI and look around if you want to, but with Docker and Kickstart, everything will already be configured correctly.

If you want to see where the FusionAuth values came from, they can be found in the FusionAuth app. The tenant Id is found on the Tenants page. To see the Client Id and Client Secret, go to the Applications page and click the View icon under the actions for the ChangeBank application. You'll find the Client Id and Client Secret values in the OAuth configuration section.

The .env file contains passwords. In a real application, always add this file to your .gitignore file and never commit secrets to version control.

Create Next.js Application

In this section, you’ll set up a basic Next.js application with two pages.

  1. Homepage
  2. Account - protected

Create a new application using the npx.

npx create-next-app@latest changebank --ts --eslint --no-tailwind --src-dir --app --import-alias "@/*"

Make sure you are in your new directory changebank.

cd changebank

Install NextAuth.js, which simplifies integrating with FusionAuth and creating a secure web application.

npm install next-auth

Copy environment variables from our complete application example.

cp ../complete-application/.env.example .env.local

Also copy an image file into a new directory within public called img.

mkdir ./public/img && cp ../complete-application/public/img/money.jpg ./public/img/money.jpg

As you will be recreating all of the files in our app directory, please delete all files within /src/app.

rm -rf ./src/app && mkdir ./src/app

Authentication

Next.js 13.2 introduced Route Handlers, which are the preferred way to handle REST-like requests. In the Changebank application you can configure NextAuth.js FusionAuth’s provider in a new route handler by creating a file within src/app/api/auth/[...nextauth]/route.ts.

On first load of Next.js this file will make sure that you have all of the correct environment variables. The variables are then exported in an object called authOptions which can be imported on the server when you need to get our session using getServerSession.

The FusionAuthProvider is then provided to NextAuth as a provider for any GET or POST commands that are sent to the /api/auth/* route.

Create a new file named src/app/api/auth/[...nextauth]/route.ts and copy the following code for the ChangeBank application.

import NextAuth from "next-auth"
import FusionAuthProvider from "next-auth/providers/fusionauth"

const fusionAuthIssuer = process.env.FUSIONAUTH_ISSUER;
const fusionAuthClientId = process.env.FUSIONAUTH_CLIENT_ID;
const fusionAuthClientSecret = process.env.FUSIONAUTH_CLIENT_SECRET;
const fusionAuthUrl = process.env.FUSIONAUTH_URL;
const fusionAuthTenantId = process.env.FUSIONAUTH_TENANT_ID;

const missingError = 'missing in environment variables.';
if (!fusionAuthIssuer) {
    throw Error('FUSIONAUTH_ISSUER' + missingError)
}
if (!fusionAuthClientId) {
    throw Error('FUSIONAUTH_CLIENT_ID' + missingError)
}
if (!fusionAuthClientSecret) {
    throw Error('FUSIONAUTH_CLIENT_SECRET' + missingError)
}
if (!fusionAuthUrl) {
    throw Error('FUSIONAUTH_URL' + missingError)
}
if (!fusionAuthTenantId) {
    throw Error('FUSIONAUTH_TENANT_ID' + missingError)
}

export const authOptions =
{
    providers: [
        FusionAuthProvider({
            issuer: fusionAuthIssuer,
            clientId: fusionAuthClientId,
            clientSecret: fusionAuthClientSecret,
            wellKnown: `${fusionAuthUrl}/.well-known/openid-configuration/${fusionAuthTenantId}`,
            tenantId: fusionAuthTenantId, // Only required if you're using multi-tenancy
        }),
    ],
}

const handler = NextAuth(authOptions)

export { handler as GET, handler as POST }

App Customization

Styles

Create a new file named src/app/globals.css and copy the below CSS for the ChangeBank application.

h1 {
  color: #096324;
}

h3 {
  color: #096324;
  margin-top: 20px;
  margin-bottom: 40px;
}

a {
  color: #096324;
}

p {
  font-size: 18px;
}

.header-email {
  color: #096324;
  margin-right: 20px;
}

.fine-print {
  font-size: 16px;
}

body {
  font-family: sans-serif;
  padding: 0px;
  margin: 0px;
}

.h-row {
  display: flex;
  align-items: center;
}

#page-container {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
}

#page-header {
  flex: 0;
  display: flex;
  flex-direction: column;
}

#logo-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px;
}

.menu-bar {
  display: flex;
  flex-direction: row-reverse;
  align-items: center;
  height: 35px;
  padding: 15px 50px 15px 30px;
  background-color: #096324;
  font-size: 20px;
}

.menu-link {
  font-weight: 600;
  color: #ffffff;
  margin-left: 40px;
}

.menu-link {
  font-weight: 600;
  color: #ffffff;
  margin-left: 40px;
}

.inactive {
  text-decoration-line: none;
}

.button-lg {
  width: 150px;
  height: 30px;
  background-color: #096324;
  color: #ffffff;
  font-size: 16px;
  font-weight: 700;
  border-radius: 10px;
  text-align: center;
  text-decoration-line: none;
  cursor: pointer;
}

.column-container {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
}

.content-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 60px 20px 20px 40px;
}

.balance {
  font-size: 50px;
  font-weight: 800;
}

.change-label {
  font-size: 20px;
  margin-right: 5px;
}

.change-input {
  font-size: 20px;
  height: 40px;
  text-align: end;
  padding-right: 10px;
}

.change-submit {
  font-size: 15px;
  height: 40px;
  margin-left: 15px;
  border-radius: 5px;
}

.change-message {
  font-size: 20px;
  margin-bottom: 15px;
}

.error-message {
  font-size: 20px;
  color: #ff0000;
  margin-bottom: 15px;
}

.app-container {
  flex: 0;
  min-width: 440px;
  display: flex;
  flex-direction: column;
  margin-top: 40px;
  margin-left: 80px;
}

.change-container {
  flex: 1;
}

Login Button

Create a new file in src/components/LoginButton.tsx that will be used for a button component. Our login button will only be used on the client side so make sure to add use client at the top of this file. For this button you can use the signIn and signOut functions from next-auth/react. By passing in the session from our pages you can determine if the Log in or Log out should be shown.

Copy the below code for the ChangeBank application into src/components/LoginButton.tsx.

'use client';

import { signIn, signOut } from 'next-auth/react';

export default function LoginButton({ session }: { session: any }) {
  if (session) {
    return (
      <>
        Status: Logged in as {session?.user?.email} <br />
        <button className="button-lg" onClick={() => signOut()}>
          Log out
        </button>
      </>
    );
  }
  return (
    <>
      <button className="button-lg" onClick={() => signIn()}>
        Log in
      </button>
    </>
  );
}

Create a new file in src/components/LoginLink.tsx that will be used for a link component. Our login link will only be used on the client side so make sure to add use client at the top of this file. For this link you can use the signIn function from next-auth/react.

Copy the below code for the ChangeBank application into src/components/LoginLink.tsx.

'use client';

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

export default function LoginButton({ session }: { session: any }) {
  return (
    <>
      <p>
        To get started,{' '}
        <a
          onClick={() => signIn()}
          style={{ textDecoration: 'underline', cursor: 'pointer' }}
        >
          log in or create a new account.
        </a>
      </p>
    </>
  );
}

Layout

If this is your first time using the Next.js App Router, you should read through Routing Fundamentals.

Below you will find the full code for the Root Layout.

This has the overall structure of our application. The other pages will be added where {children} is located.

Create a new file named src/app/layout.tsx and copy the below code to create the layout for the ChangeBank application.

import './globals.css';
import type { Metadata } from 'next';
import Image from 'next/image';
import LoginButton from '../components/LoginButton';

import { getServerSession } from 'next-auth/next';
import { authOptions } from './api/auth/[...nextauth]/route';

export const metadata: Metadata = {
  title: 'FusionAuth Next.js with NextAuth.js',
  description: 'Generated by create next app',
};

export default async function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  const session = await getServerSession(authOptions);

  return (
    <html lang="en">
      <body>
        <div id="page-container">
          <div id="page-header">
            <div id="logo-header">
              <Image
                src="https://fusionauth.io/assets/img/samplethemes/changebank/changebank.svg"
                alt="change bank logo"
                width="257"
                height="55"
              />
              <LoginButton session={session} />
            </div>

            <div id="menu-bar" className="menu-bar">
              {session ? (
                <>
                  <a
                    href="/makechange"
                    className="menu-link"
                    style={{ textDecorationLine: 'underline' }}
                  >
                    Make Change
                  </a>
                  <a
                    href="/account"
                    className="menu-link"
                    style={{ textDecorationLine: 'underline' }}
                  >
                    Account
                  </a>
                </>
              ) : (
                <>
                  <a className="menu-link">About</a>
                  <a className="menu-link">Services</a>
                  <a className="menu-link">Products</a>
                  <a
                    className="menu-link"
                    style={{ textDecorationLine: 'underline' }}
                  >
                    Home
                  </a>
                </>
              )}
            </div>
          </div>
          {children}
        </div>
      </body>
    </html>
  );
}

Home Page

Create a new file src/app/page.tsx which will have the Homepage details. Not much here just an image and another Login button.

import { getServerSession } from 'next-auth';
import Image from 'next/image';
import { redirect } from 'next/navigation';
import { authOptions } from './api/auth/[...nextauth]/route';
import LoginLink from '../components/LoginLink';

export default async function Home() {
  const session = await getServerSession(authOptions);

  if (session) {
    redirect('/account');
  }
  return (
    <main>
      <div style={{ flex: '1' }}>
        <div className="column-container">
          <div className="content-container">
            <div style={{ marginBottom: '100px' }}>
              <h1>Welcome to Changebank</h1>
              <LoginLink session={session} />
            </div>
          </div>
          <div style={{ width: '100%', maxWidth: 800 }}>
            <Image
              src="/img/money.jpg"
              alt="money"
              width={1512}
              height={2016}
              style={{
                objectFit: 'contain',
                width: '100%',
                position: 'relative',
                height: 'unset',
              }}
            />
          </div>
        </div>
      </div>
    </main>
  );
}

Account Page

Create a new file src/app/account/page.tsx which will have the Account details.

One special note here is that there is a check to see if the session is missing. If it is, you redirect back to the homepage which protects this page on the server for unauthorized access. (You can find the same when a user is logged in on the homepage, it will redirect to /account)

Here’s the contents of src/app/account/page.tsx.

import { getServerSession } from 'next-auth';
import Image from 'next/image';
import { authOptions } from '../api/auth/[...nextauth]/route';
import { redirect } from 'next/navigation';

export default async function Account() {
  const session = await getServerSession(authOptions);

  if (!session) {
    redirect('/');
  }
  return (
    <section>
      <div style={{ flex: '1' }}>
        <div className="column-container">
          <div className="app-container">
            <h3>Your balance</h3>
            <div className="balance">$0.00</div>
          </div>
        </div>
      </div>
    </section>
  );
}

Make Change Page

Finally, we’ll add some business logic for logged in users to make change with the following code in src/app/makechange/page.tsx:

import { getServerSession } from 'next-auth';
import { authOptions } from '../api/auth/[...nextauth]/route';
import { redirect } from 'next/navigation';
import MakeChangeForm from '../../components/MakeChangeForm';

export default async function MakeChange() {
  const session = await getServerSession(authOptions);

  if (!session) {
    redirect('/');
  }
  return (
    <>
      <MakeChangeForm />
    </>
  );
}

If the user session is not present the user is redirect back the the homepage at the base route. If the user is present then the MakeChangeForm is presented. Create a new file located at /src/components/MakeChangeForm.tsx with the below code. This component has all of the business logic needed for taking in a dollar amount of money and returning the correct amount of each coin.

'use client';

import { useEffect, useState } from 'react';

var coins = {
  quarters: 0.25,
  dimes: 0.1,
  nickels: 0.05,
  pennies: 0.01,
};

export default function MakeChangeForm() {
  const [message, setMessage] = useState('');
  const [amount, setAmount] = useState(0);
  useEffect(() => {
    setMessage('');
    setAmount(0);
  }, []);

  const onMakeChange = (event: any) => {
    event.preventDefault();

    try {
      setMessage('We can make change for');

      let remainingAmount = amount;
      for (const [name, nominal] of Object.entries(coins)) {
        let count = Math.floor(remainingAmount / nominal);
        remainingAmount =
          Math.ceil((remainingAmount - count * nominal) * 100) / 100;

        setMessage((m) => `${m} ${count} ${name}`);
      }
      setMessage((m) => `${m}!`);
    } catch (ex: any) {
      setMessage(
        `There was a problem converting the amount submitted. ${ex.message}`
      );
    }
  };

  return (
    <section>
      <div style={{ flex: '1' }}>
        <div className="column-container">
          <div className="app-container change-container">
            <h3>We Make Change</h3>
            <div className="change-message">{message}</div>
            <form onSubmit={onMakeChange}>
              <div className="h-row">
                <div className="change-label">Amount in USD: $</div>
                <input
                  className="change-input"
                  type="number"
                  step={0.01}
                  name="amount"
                  value={amount}
                  onChange={(e) => setAmount(+e.target.value)}
                />
                <input
                  className="change-submit"
                  type="submit"
                  value="Make Change"
                />
              </div>
            </form>
          </div>
        </div>
      </div>
    </section>
  );
}

Run the Application

You can now open up an incognito window and visit the NextJS app at http://localhost:3000/. Log in with the user account you created when setting up FusionAuth, and you’ll see the email of the user next to a logout button.

npm run dev

Try clicking the Login button at the top or center of the screen.

This will take you through the NextAuth.js authentication flow. First prompting you to select Sign in with FusionAuth.

You can then login to FusionAuth with Email: richard@example.com Password: password (as you might expect not ideal for production.)

This will then take you back to the application in the API route it will check for a session and appropriately redirect you to the /account route when your session has been established.

Next Steps

This quickstart is a great way to get a proof of concept up and running quickly, but to run your application in production, there are some things you're going to want to do.

FusionAuth Customization

FusionAuth gives you the ability to customize just about everything to do with the user's experience and the integration of your application. This includes:

Security

Tenant and Application Management