Introduction

In modern web development, authentication is a crucial aspect of building secure and user-friendly applications. Firebase Authentication provides developers with a robust solution for user authentication, allowing them to integrate authentication quickly and securely into their applications. When combined with the latest features of Next.js, a powerful React framework, developers can create seamless authentication experiences for their users while leveraging the benefits of server-side rendering and static site generation. In this article, we’ll explore how to integrate Firebase Authentication with Next.js, taking advantage of its latest features.

Setting Up Firebase Authentication

First, let’s set up Firebase Authentication in our Next.js project. Start by creating a Firebase project in the Firebase console and enabling the authentication feature. Once you have your Firebase project set up, install the Firebase SDK in your Next.js project using npm or yarn:

bash
npm install firebase

Next, initialize Firebase in your Next.js application by creating a firebase.js file in your project’s lib directory:

javascript
// lib/firebase.js
import firebase from 'firebase/app';
import 'firebase/auth';
const firebaseConfig = {
apiKey: ‘YOUR_API_KEY’,
authDomain: ‘YOUR_AUTH_DOMAIN’,
projectId: ‘YOUR_PROJECT_ID’,
// Add more Firebase config options here…
};if (!firebase.apps.length) {
firebase.initializeApp(firebaseConfig);
}export default firebase;

Replace 'YOUR_API_KEY', 'YOUR_AUTH_DOMAIN', and 'YOUR_PROJECT_ID' with your Firebase project’s configuration details.

Implementing Authentication Features

With Firebase initialized in our Next.js project, we can now implement authentication features such as user sign-up, sign-in, sign-out, and user state management.

User Sign-Up

To allow users to sign up for your application, create a sign-up form component and handle form submission with Firebase:

javascript
// components/SignUpForm.js
import { useState } from 'react';
import firebase from '../lib/firebase';
const SignUpForm = () => {
const [email, setEmail] = useState();
const [password, setPassword] = useState();const handleSignUp = async (e) => {
e.preventDefault();
try {
await firebase.auth().createUserWithEmailAndPassword(email, password);
// User signed up successfully
} catch (error) {
// Handle sign-up errors
}
};return (
<form onSubmit={handleSignUp}>
<input
type=“email”
value={email}
onChange={(e) =>
setEmail(e.target.value)}
placeholder=”Email”
/>
<input
type=“password”
value={password}
onChange={(e) =>
setPassword(e.target.value)}
placeholder=”Password”
/>
<button type=“submit”>Sign Up</button>
</form>

);
};

export default SignUpForm;

User Sign-In

Similarly, implement a sign-in form component to allow users to sign in to your application:

javascript
// components/SignInForm.js
import { useState } from 'react';
import firebase from '../lib/firebase';
const SignInForm = () => {
const [email, setEmail] = useState();
const [password, setPassword] = useState();const handleSignIn = async (e) => {
e.preventDefault();
try {
await firebase.auth().signInWithEmailAndPassword(email, password);
// User signed in successfully
} catch (error) {
// Handle sign-in errors
}
};return (
<form onSubmit={handleSignIn}>
<input
type=“email”
value={email}
onChange={(e) =>
setEmail(e.target.value)}
placeholder=”Email”
/>
<input
type=“password”
value={password}
onChange={(e) =>
setPassword(e.target.value)}
placeholder=”Password”
/>
<button type=“submit”>Sign In</button>
</form>

);
};

export default SignInForm;

User Sign-Out

For signing out users, create a sign-out button component:

javascript
// components/SignOutButton.js
import firebase from '../lib/firebase';
const SignOutButton = () => {
const handleSignOut = async () => {
try {
await firebase.auth().signOut();
// User signed out successfully
} catch (error) {
// Handle sign-out errors
}
};return <button onClick={handleSignOut}>Sign Out</button>;
};export default SignOutButton;

Managing User State

Next.js provides a great way to manage user authentication state using its built-in getServerSideProps and useEffect hooks. You can fetch the current user’s authentication state on the server side and pass it as props to your pages:

javascript
// pages/index.js
import { useEffect, useState } from 'react';
import { useRouter } from 'next/router';
import firebase from '../lib/firebase';
const Home = ({ user }) => {
const router = useRouter();useEffect(() => {
if (!user) {
router.push(‘/signin’);
}
}, [user]);return (
<div>
<h1>Welcome to the Home Page!</h1>
<p>User: {user ? user.email : ‘Not signed in’}</p>
</div>

);
};

export async function getServerSideProps(context) {
const { req } = context;
let user = null;

try {
const token = await firebase.auth().verifyIdToken(req.cookies.token);
user = { email: token.email };
} catch (error) {
// User is not authenticated
}

return { props: { user } };
}

export default Home;

In this example, we use the getServerSideProps function to fetch the user’s authentication state on the server side and pass it as props to the Home component. If the user is not authenticated, we redirect them to the sign-in page.

Conclusion

Integrating Firebase Authentication with the latest features of Next.js provides a robust solution for building secure web applications. By leveraging Next.js’s serverless functions and Firebase’s authentication capabilities, developers can create scalable applications with minimal backend setup. Whether you’re building a simple login system or a complex web application, this integration offers a solid foundation for handling user authentication efficiently.

In this article, we covered the setup of Firebase Authentication, the integration of serverless functions with Next.js, and the implementation of a login page using Firebase Authentication. With this knowledge, you’re well-equipped to incorporate authentication into your Next.js projects, ensuring a seamless and secure user experience.