Flutter Firebase Authentication: Easy User Authentication for Your App

If you are building a mobile application, authentication is a critical feature that you need to include. You want to be sure that you are dealing with the right users and that they are who they say they are. Firebase Authentication simplifies the authentication process, so you don't need to spend time building it from scratch.

Getting Started

First, you will need to set up Firebase Authentication in your project by following these steps:

1. Create or log in to your Firebase account
2. Create a new project
3. Add Firebase to your project
4. Enable Firebase Authentication in your project
5. Add Firebase Authentication dependencies to your project

Once you have set up Firebase Authentication in your project, you can start using it to authenticate users.

Email/Password Auth

One of the easiest ways to authenticate users using Firebase Authentication is through email and password. With Firebase Authentication, you can easily create and manage users, as well as authenticate them with email and password.

To create a new email/password user, you can use the following code:

import 'package:firebase_auth/firebase_auth.dart';

final FirebaseAuth _auth = FirebaseAuth.instance;

Future createUserWithEmailAndPassword(
  String email, String password) async {
  final UserCredential userCredential = await _auth
      .createUserWithEmailAndPassword(email: email, password: password);
  final User user = userCredential.user;
  return user.uid;
}

To log in an email/password user, you can use the following code:

Future signInWithEmailAndPassword(
  String email, String password) async {
  final UserCredential userCredential = await _auth.signInWithEmailAndPassword(
      email: email, password: password);
  final User user = userCredential.user;
  return user.uid;
}

Google Sign-In

A popular way to authenticate users in mobile applications is through Google Sign-In. Firebase Authentication integrates with Google Sign-In, so you can easily set up Google Sign-In authentication in your app.

To enable Google Sign-In for Firebase Authentication, follow these steps:

1. Set up Firebase Authentication
2. Enable Google Sign-In in the Firebase console
3. Add the Google Services plugin to your app
4. Configure your Firebase project to use Google Sign-In
5. Implement Google Sign-In in your app

Once you have enabled Google Sign-In in your Firebase project, you can use the following code to authenticate users with Google Sign-In:

import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';

final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn _googleSignIn = GoogleSignIn();

Future signInWithGoogle() async {
  final GoogleSignInAccount googleSignInAccount = await _googleSignIn.signIn();
  final GoogleSignInAuthentication googleSignInAuthentication =
      await googleSignInAccount.authentication;
  final AuthCredential credential = GoogleAuthProvider.credential(
    accessToken: googleSignInAuthentication.accessToken,
    idToken: googleSignInAuthentication.idToken,
  );
  final UserCredential userCredential = await _auth.signInWithCredential(credential);
  final User user = userCredential.user;
  return user.uid;
}

Summary

Firebase Authentication is an easy and powerful way to authenticate users for your mobile app. With Firebase Authentication, you can easily manage your users and authenticate them using email/password or Google Sign-In.