firebase_auth: SAMLAuthProvider throws an error with loginWithSSOProvider

[ohhyungkwon]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Auth

Which platforms are affected?

iOS

Description

When signInWithProvider is called with SAMLAuthProvider, the login seems successful but it throws an error like below:

loginWithSSOProvider error: type 'String' is not a subtype of type 'Map<dynamic, dynamic>?'

Reproducing the issue

final provider = SAMLAuthProvider('saml.mycompany.com');

UserCredential userCredential = await FirebaseAuth.instance.signInWithProvider(provider);

Firebase Core version

3.10.0

Flutter Version

3.22.3

Relevant Log Output

Error received from Flutter ["exceptionDescription": type 'String' is not a subtype of type 'Map<dynamic, dynamic>?'#0      platformExceptionToFirebaseAuthException (package:firebase_auth_platform_interface/src/method_channel/utils/exception.dart:47:25), "stackTraceDescription": #0      platformExceptionToFirebaseAuthException (package:firebase_auth_platform_interface/src/method_channel/utils/exception.dart:47:25)
#1      convertPlatformException (package:firebase_auth_platform_interface/src/method_channel/utils/exception.dart:26:5)
#2      MethodChannelFirebaseAuth.signInWithProvider (package:firebase_auth_platform_interface/src/method_channel/method_channel_firebase_auth.dart:405:7)
<asynchronous suspension>
#3      FirebaseAuth.signInWithProvider (package:firebase_auth/src/firebase_auth.dart:641:9)
<asynchronous suspension>
]

Flutter dependencies

Expand Flutter dependencies snippet

Dart SDK 3.4.4
Flutter SDK 3.22.3

dependencies:
...
- firebase_auth: ^5.4.0
- firebase_core: ^3.10.0
...

Additional context and comments

Android also throws an error but it it different with iOS. The Android throws below error.

loginWithSSOProvider error: [firebase_auth/unknown] https://myproject.firebaseapp.com/__/auth/handler?providerId= saml.mycompany.com

[MichaelVerdon]

We've been unable to reproduce the issue but if you could provide a minimal reproducible example in the form of a repo that would be really helpful.

[ohhyungkwon]

@MichaelVerdon It looks like the package does not handle the error properly.

1. signInWithProvider in messages.pigeon.dart throws PlatformException error like below.

2. signInWithProvider in method_channel_firebase_auth.dart catches the exception and converts the exception.

convertPlatformException causes another exception and it wipes original error which is PlatformException(sign-in-failed, An internal error has occurred, print and inspect the error details for more information., INVALID_CREDENTIAL_OR_PROVIDER_ID : Invalid IdP response/credential: https://myproject.firebaseapp.com/__/auth/handler?providerId= saml.mycompany.com, null).

[ohhyungkwon]

Apart from above issue, the original or platform error says there is an invalid provider id.

The SAML is from Google Workspace and it is working fine using the web SDK.

Does flutterfire support SAML for Android and iOS? I can see this firebase/firebase-android-sdk#662.

[MichaelVerdon]

From what I understand, the mobile SDKs do not natively support SAML the same way that web does so we will be investigating a work around.