cd39d3178c
* Add this as a guide for Firebase Auth. This is a thorough guide on how to implement Google sign-in using firebase authentication. * made folder name lowercase * updated directory name and frontmatter title
138 lines
5.8 KiB
Markdown
138 lines
5.8 KiB
Markdown
---
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title: Setting up Firebase Authentication
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---
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# Setting up Firebase Authentication
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## Prerequisites
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1. The latest version of Android Studio
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2. Have connected with Firebase manually or via Firebase Assistant (See [Connecting to Firebase](guide/src/pages/android-development/firebase/connecting-to-firebase)).
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It is recommended that you do this so as to not be confused by partial instructions related to this in the docs mentioned below.
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## Setting it up with Android Studio
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After adding Firebase to your project, you will need to add extra dependencies and do some other things in order to setup
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the Firebase Authentication for Google sign-in. There are following documentation about this:
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* [Firebase](https://firebase.google.com/docs/storage/android/start)
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There may be chance of confusion in that documentation or if you are new to firebase then you may face little bit hard to understand it.
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So follow the belows steps carefully:
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**Add Gradle Dependencies**
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In your app-level build.gradle file, add the following
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```java
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dependencies {
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implementation 'com.google.firebase:firebase-auth:16.0.4'
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implementation 'com.google.android.gms:play-services-auth:16.0.1'
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}
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```
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## Installation of Firebase Android SDK, permissions and setup code
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Detailed instructions for these can be found [here](https://firebase.google.com/docs/android/setup).
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## Resources
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* [SHA-1 fingerprint](https://developers.google.com/android/guides/client-auth)
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It is important that after you connect your project to firebase you should specify SHA-1 fingerprint, do so from the Settings page of the Firebase console.
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* [Enable Google Sign-In in the Firebase console]
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1. In the Firebase console, open the Auth section.
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2. On the Sign in method tab, enable the Google sign-in method and click Save.
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There are four steps that must be followed for the sign-in:
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1. Integrate Google Sign-In bt following the link attached [Integrating Google Sign-In into Your Android App page](https://developers.google.com/identity/sign-in/android/sign-in) this helps in setting up the login button, checking for existing users etc. When you configure the GoogleSignInOptions object, call requestIdToken:
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```
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GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
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.requestIdToken(getString(R.string.default_web_client_id))
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.requestEmail()
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.build();
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```
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You must pass your server's client ID to the requestIdToken method. To find the OAuth 2.0 client ID:
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1. Open the [Credentials](https://console.developers.google.com/apis/credentials) page in the API Console.
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2. The Web application type client ID is your backend server's OAuth 2.0 client ID.
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After you integrate Google Sign-In, your sign-in activity has code similar to the following:
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```
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private void signIn() {
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Intent signInIntent = mGoogleSignInClient.getSignInIntent();
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startActivityForResult(signInIntent, RC_SIGN_IN);
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}
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@Override
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public void onActivityResult(int requestCode, int resultCode, Intent data) {
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super.onActivityResult(requestCode, resultCode, data);
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// Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
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if (requestCode == RC_SIGN_IN) {
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Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
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try {
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// Google Sign In was successful, authenticate with Firebase
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GoogleSignInAccount account = task.getResult(ApiException.class);
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firebaseAuthWithGoogle(account);
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} catch (ApiException e) {
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// Google Sign In failed, update UI appropriately
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Log.w(TAG, "Google sign in failed", e);
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// ...
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}
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}
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}
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```
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2. In your sign-in activity's onCreate method, get the shared instance of the FirebaseAuth object:
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```
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private FirebaseAuth mAuth;
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// ...
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// Initialize Firebase Auth
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mAuth = FirebaseAuth.getInstance();
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```
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3. It is important to check if the a user has already participated and initialized his gmail account with application hence onStart you need to test the user status:
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```
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@Override
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public void onStart() {
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super.onStart();
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// Check if user is signed in (non-null) and update UI accordingly.
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FirebaseUser currentUser = mAuth.getCurrentUser();
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if(currentUser!=Null){
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//User exists
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}
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}
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```
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4. Finally, after a user successfully signs in, get the ID token from the GoogleSignInAccount object, exchange it for a Firebase credential, and authenticate with Firebase using the Firebase credential, without this step your user details will not be logged in the Firebase Auth user list:
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```
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private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
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Log.d(TAG, "firebaseAuthWithGoogle:" + acct.getId());
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AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
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mAuth.signInWithCredential(credential)
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.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
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@Override
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public void onComplete(@NonNull Task<AuthResult> task) {
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if (task.isSuccessful()) {
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// Sign in success, update UI with the signed-in user's information
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Log.d(TAG, "signInWithCredential:success");
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FirebaseUser user = mAuth.getCurrentUser();
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updateUI(user);
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} else {
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// If sign in fails, display a message to the user.
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Log.w(TAG, "signInWithCredential:failure", task.getException());
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Snackbar.make(findViewById(R.id.main_layout), "Authentication Failed.", Snackbar.LENGTH_SHORT).show();
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updateUI(null);
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}
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// ...
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}
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});
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}
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```
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## Note
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Google now deprecated 'compile' and in place of that you need to use 'implementation'.
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