Firebase Auth

Firebase Auth is a service offered by Firebase that allows developers to add authentication to their mobile and web applications. With Firebase Auth, developers can:

• Authenticate users with email and password
• Authenticate users using popular third-party login providers (such as Google, Facebook, Twitter, etc.)
• Authenticate users using custom authentication methods (such as phone number authentication)
• Manage user passwords and account information
• Implement security features (such as two-factor authentication)

Firebase Auth also offers a fully-featured client-side authentication API, as well as server-side authentication libraries for popular languages such as Java, Python, and Node.js.

Getting Started

To use Firebase Auth, you'll first need to create a Firebase project and add Firebase to your mobile or web application. Once you've done that, you can follow these steps to add authentication:

Step 1: Enable Authentication Providers

Go to the "Authentication" tab of your Firebase project's console, and enable the authentication providers you want to use (such as email/password, Google, Facebook, etc.).

Step 2: Integrate the Firebase Authentication SDK

For mobile applications, add the Firebase Authentication SDK to your app by adding the following dependencies to your project:

dependencies {
    // ...

    implementation 'com.google.firebase:firebase-auth:19.3.2'
}

For web applications, include the Firebase Authentication SDK by adding the following script to your HTML page:

<script src="https://www.gstatic.com/firebasejs/7.19.0/firebase-auth.js"></script>

Step 3: Integrate Authentication into your App

Using Firebase Auth is different depending on whether you're using a mobile or web application. However, the basic process is the same:

1. Create a Firebase Auth instance:

FirebaseAuth mAuth = FirebaseAuth.getInstance();

2. Implement a sign-in method, such as email/password sign-in or third-party sign-in:

// Email/password sign-in
mAuth.signInWithEmailAndPassword(email, password)
    .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
        @Override
        public void onComplete(@NonNull Task<AuthResult> task) {
            if (task.isSuccessful()) {
                // Sign in success, update UI with the signed-in user's information
            } else {
                // If sign in fails, display a message to the user.
            }
        }
    });

// Third-party sign-in (Google)
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
        .requestIdToken(getString(R.string.default_web_client_id))
        .requestEmail()
        .build();

GoogleSignInClient mGoogleSignInClient = GoogleSignIn.getClient(this, gso);

Intent signInIntent = mGoogleSignInClient.getSignInIntent();
startActivityForResult(signInIntent, RC_SIGN_IN);

// In onActivityResult
Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
handleSignInResult(task);

3. Implement sign-out and delete-account methods:

// Sign out
mAuth.signOut();

// Delete account
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();

user.delete()
    .addOnCompleteListener(new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            if (task.isSuccessful()) {
                // Account deleted successfully
            } else {
                // Account deletion failed
            }
        }
    });

Conclusion

Firebase Auth is a powerful authentication service that allows developers to easily add authentication to their mobile and web applications. By following the steps outlined above, you can easily integrate Firebase Auth into your own application!

References

• Firebase Auth documentation
• Firebase Auth Android documentation
• Firebase Auth iOS documentation
• Firebase Auth Web documentation