Firebase Custom Tokens generated by this are invalid

[jpeiffer]

Version: firebase_admin: ^0.2.0-dev.1

The Firebase custom tokens generated by this library result in an auth error from the Firebase servers:

The custom token format is incorrect. Please check the documentation.

It appears this library is putting in extra attributes that are not put in via the Java SDK. Specifically, this puts in a kid and a typ attribute in the header that the Java SDK doesn't.

I tried generating a token manually without those attributes and it was accepted by Firebase. Through some more experimentation, it's the typ attribute that's causing Firebase to reject the token as invalid as it accepts it still with the kid in place.

It looks like all that needs to change is to remove the typ header. The fix would be to change: lib/src/auth/token_tenerator.dart

Around lines 68-70... from:

    var builder = JsonWebSignatureBuilder()
      ..jsonContent = claims
      ..setProtectedHeader('typ', 'JWT')
      ..addRecipient(certificate.privateKey, algorithm: 'RS256');

... to ...

    var builder = JsonWebSignatureBuilder()
      ..jsonContent = claims
      ..addRecipient(certificate.privateKey, algorithm: 'RS256');