How to sign a Azure AD user into Firebase in a Flutter mobile app?

Question

For a Flutter mobile app I am trying to use a Microsoft OAuthProvider to get a Firebase credential with which to sign the user into Firebase with their Azure AD account.

The closest I got was using a third party Active Directory auth package to log the user in and get an access token. However the sign-in to Firebase fails with an error message that suggests the idToken is invalid.

final AadOAuth oauth = new AadOAuth(config);
await oauth.login();

// accessToken looks legit
String accessToken = await oauth.getAccessToken();

String idToken = await oauth.getIdToken();

OAuthProvider provider = OAuthProvider('microsoft.com');

// Also tried the constructor without the idToken
OAuthCredential credential = provider.credential(accessToken: accessToken, idToken: idToken);

// app fails here:
await FirebaseAuth.instance.signInWithCredential(credential);

// this works fine, but only on web platform:
await FirebaseAuth.instance.signInWithPopup(provider);

Because it is a platform specific error (iOS in this case), the exception details are not surfaced. All I get is:

PlatformException(internal-error, ) nativeErrorCode: 17999

Here is my app settings in the Azure portal:

Full manifest here

Has anyone been successful in using Microsoft Auth to sign a user in to Firebase in a Flutter mobile app?

Solution

You can use Firebase Auth OAuth package for it.

And sign in to the firebase using the Microsoft Auth provider.

User user = await FirebaseAuthOAuth().openSignInFlow(
  "microsoft.com", ["email openid"], {'tenant': 'your-tenent-id'});

This integrates nicely with firebase so, firebase authStateChange also works with this method.

Comments

[Jannie Theunissen]

I am building a mobile app. The implicit grant flow is only available for a web app. I tried creating a web client and ticking those two boxes and including the openid scope, but the flow still fails on exactly the same line with the same error.

[svyat1s]

have you tried provider.credential with only idToken?

[svyat1s]

and do you use Azure B2C directory or regular Azure?

[Jannie Theunissen]

I don't use B2C and constructing the credential with just the id token fails on the same step, but with a slightly different error message: error code: internal-error

[kobowo]

Is there a way to use the data using this library to get a Microsoft Access token so that I can access MS Graph?

[Mateus Felipe]

Where do I get the tenant ID?

[imperial-lord]

Using this I get the error here - github.com/amrfarid140/firebase_auth_oauth/issues/49. Can anyone help?