Flutter+Firebase — Authenticate with Twitter

I really got excited seeing the latest update to the Flutter Firebase Auth plugin which adds support for Twitter and decided to try it out.

But before we begin, I have made the following assumptions

• Flutter has been installed on your computer. If in need of help the Flutter team have detailed step-by-step articles on how to get this done.
• Created a Twitter app. For more details visit Twitters app page
• You have created a firebase project with support for both Android and iOS. If in need of help this article explains the steps.
• Enabled Twitter authentication for your Firebase project. You can do this by following step 5 of Before you begin section here
• Downloaded and added both GoogleService-Info.plist and google-services.json files to Runner directory for iOS and android->app for Android.

final app demo (Android)

In order to achieve our purpose, the below plugins (listed in pubspec.yaml) were used

dependencies: firebase_auth: '^0.5.9'//we need to get a FirebaseUser
  google_sign_in: '^3.0.3' //not really needed
  flutter_twitter_login: "^1.1.0" //helps with Twitter OAuth dance
  flutter: sdk: flutter

Authenticating With Twitter

First we get a TwitterLogin using flutter_twitter_login plugin

final TwitterLogin twitterLogin = new TwitterLogin( consumerKey: Strings.twitterApiKey, 
consumerSecret: Strings.twitterApiSecret
);

Second, we get the TwitterLoginResult, TwitterLoginStatus and TwitterSession. This also using flutter_twitter_login.

_twitterLoginResult = await twitterLogin.authorize();
_currentUserTwitterSession = _twitterLoginResult.session;
_twitterLoginStatus = _twitterLoginResult.status;

We need TwitterSession to retrieve token and secret needed by FirebaseAuth.instance.signInWithTwitter(…)

Now that we have our TwitterSession, our third step will be to get a FirebaseUser provided Twitter login was successful.

_currentUser = await _firebaseAuth.signInWithTwitter(
    authToken: _currentUserTwitterSession?.token ?? '',
    authTokenSecret: _currentUserTwitterSession?.secret ?? ''
);

Not to worry, I did not forget our iOS friends

final app demo (iOS)

And this wraps the end of my very first post. Looking forward to the next one already 😃.

Whoops!! Here is the complete code on GitHuB.