How to Handle Firebase Auth exceptions on flutter

问题

Please does anyone know how to catch firebase Auth exceptions on flutter and display them,

Note: I am not interested in the console ( catcherror((e) print(e))

I need something that is more effective, e.g " user doesn't exist" So that I can then pass it to a string and display it.

Been dealing with this for months.

Thanks in advance

i have tried replacing print(e) with // errorMessage=e.toString(); and then passing it to a function, all efforts have been frutile

    FirebaseAuth.instance
              .signInWithEmailAndPassword(email: emailController.text, password: passwordController.text)
              .then((FirebaseUser user) {
                _isInAsyncCall=false;
            Navigator.of(context).pushReplacementNamed("/TheNextPage");

          }).catchError((e) {
           // errorMessage=e.toString();
            print(e);
            _showDialog(errorMessage);

            //exceptionNotice();
            //print(e);

i want to be able to extract the exception message and pass the exception message to a dialog that i can then display to the user

回答1:

The firebase auth plugin doesn't really have a proper cross-platform error code system yet so you have to handle errors for android and ios independently.

I'm currently using the temporary fix from this github issue: #20223

Do note since its a temp fix, don't expect it to be fully reliable as a permanent solution.

enum authProblems { UserNotFound, PasswordNotValid, NetworkError }

try {
  FirebaseUser user = await FirebaseAuth.instance.signInWithEmailAndPassword(
      email: email,
      password: password,
  );
} catch (e) {
  authProblems errorType;
  if (Platform.isAndroid) {
    switch (e.message) {
      case 'There is no user record corresponding to this identifier. The user may have been deleted.':
        errorType = authProblems.UserNotFound;
        break;
      case 'The password is invalid or the user does not have a password.':
        errorType = authProblems.PasswordNotValid;
        break;
      case 'A network error (such as timeout, interrupted connection or unreachable host) has occurred.':
        errorType = authProblems.NetworkError;
        break;
      // ...
      default:
        print('Case ${e.message} is not yet implemented');
    }
  } else if (Platform.isIOS) {
    switch (e.code) {
      case 'Error 17011':
        errorType = authProblems.UserNotFound;
        break;
      case 'Error 17009':
        errorType = authProblems.PasswordNotValid;
        break;
      case 'Error 17020':
        errorType = authProblems.NetworkError;
        break;
      // ...
      default:
        print('Case ${e.message} is not yet implemented');
    }
  }
  print('The error is $errorType');
}

回答2:

Expanding on the accepted answer I thought it's worth to mention that:

The firebase_auth plugin has AuthException.
As pointed out in this Github issue post you can have the same error codes for Android and iOS.
If you have this code in a non-UI layer you can use rethrow or better throw your own formatted exceptions and catch those at the UI level (where you'll know exactly the kind of error you'll get).

try {
  AuthResult authResult = await FirebaseAuth.instance.signInWithCredential(credential);
  // Your auth logic ...
} on AuthException catch (e) {
  print('''
    caught firebase auth exception\n
    ${e.code}\n
    ${e.message}
  ''');

  var message = 'Oops!'; // Default message
  switch (e.code) {
    case 'ERROR_WRONG_PASSWORD':
      message = 'The password you entered is totally wrong!';
      break;
    // More custom messages ...
  }
  throw Exception(message); // Or extend this with a custom exception class
} catch (e) {
  print('''
    caught exception\n
    $e
  ''');
  rethrow;
}

回答3:

I just coded myself a way to do this without Platform dependent Code:

This is possible since .signInWithEmailAndPassword correctly throws Errors with defined codes, that we can grab to identify the error and handle things in the way the should be handled.

The following example creates a new Future.error, if any error happens, and a Bloc is then configured to shovel that data through to the Widget.

Future<String> signIn(String email, String password) async {
  FirebaseUser user;
  String errorMessage;

  try {
    AuthResult result = await _firebaseAuth.signInWithEmailAndPassword(email: email, password: password);
    user = result.user;
  } catch (error) {
    switch (error.code) {
      case "ERROR_INVALID_EMAIL":
        errorMessage = "Your email address appears to be malformed.";
        break;
      case "ERROR_WRONG_PASSWORD":
        errorMessage = "Your password is wrong.";
        break;
      case "ERROR_USER_NOT_FOUND":
        errorMessage = "User with this email doesn't exist.";
        break;
      case "ERROR_USER_DISABLED":
        errorMessage = "User with this email has been disabled.";
        break;
      case "ERROR_TOO_MANY_REQUESTS":
        errorMessage = "Too many requests. Try again later.";
        break;
      case "ERROR_OPERATION_NOT_ALLOWED":
        errorMessage = "Signing in with Email and Password is not enabled.";
        break;
      default:
        errorMessage = "An undefined Error happened.";
    }
  }

  if (errorMessage != null) {
    return Future.error(errorMessage);
  }

  return user.uid;
}

来源：https://stackoverflow.com/questions/56113778/how-to-handle-firebase-auth-exceptions-on-flutter

标签

firebase

Flutter

firebase-authentication