Cognito with MFA and Flutter - Flow

Question

I am trying to log into AWS Cognito and have configured the user pool to have MFA via email. I have it 99% working, but am experiencing a weird error at the end. I am using Flutter and the amazon_cognito_identity_dart_2 flutter package. My users are created by an admin and users are not allowed to sign up in the app itself. My flow goes like such:

//global var
final userPool = new CognitoUserPool(
    CognitoConstants.poolID,
    CognitoConstants.appClientID,
  );
...
///in login function
final authDetails = new AuthenticationDetails(
      username: email,
      password: password,
    );
final cognitoUser = new CognitoUser(email, userPool);
try {
      session = await cognitoUser.authenticateUser(authDetails);
    } catch (e) {}

The above try catches a CognitoUserNewPasswordRequiredException exception the first time the user logs in because they must change their password as a temp password was mailed to them on account creation. So then I call the below function to reset the password:

try {
      session = await user.sendNewPasswordRequiredAnswer(newPassword);
    } catch (e) {}

The above throws a CognitoUserMfaSetupException exception because MFA is enabled but the device is not known. However, this password definitely works and I can log in (but not proceed). So now I am kind of stuck on what to do. I have tried a few different things, but none seem to work. Here is what I have tried and am the closest:

user.resendConfirmationCode(); //sends code to email
///await modal to grab MFA response and store it in token variable.
try {
   print('Username: ${user.username}');
   session = await user.sendMFACode(token, 'SOFTWARE_TOKEN_MFA');
} catch (e) {}

The above try/catch always catches an error and says "CognitoClientException{statusCode: 400, code: CodeMismatchException, name: CodeMismatchException, message: Invalid code or auth state for the user.}" However, I know the code is correct, so it must be the auth state of the user. But how can I ensure the auth state is good here? I think I am missing another step, and have tried the documents in: https://docs.aws.amazon.com/cognito/latest/developerguide/how-to-create-user-accounts.html and also all the examples in the pub.dev package, but none seem that great for dealing with MFA. If I print the user.username out, as in this example above, the email is in fact printed out so it knows the details on the user. Any ideas? Thanks in advance!

Cognito with MFA and Flutter -> Flow

0 Answers