使用 Flutter 和 Ferry 获取数据后，无法使用来自 GraphQl 查询的数据

Question

I currently have a function in a bloc which is calling my repository to grab data from my server using GraphQL. I am able to get the data back. However I am not able to return it to my bloc as the function exits out after grabbing the data.

Here is the code in my bloc....

Either<AuthFailure, GLoginData_login> failureOrSuccess;

   failureOrSuccess = await loginWithUsernameAndPassword(username: state.username, password: state.password)
       .whenComplete(() {             <---------- This line is never triggered (why not?)
     failureOrSuccess.fold((l) => null, (r) {
       print('You have the data $r'); 
     });
   });

As you can see I am awaiting for the response from the forwardedCall.

Here is the code in my repository which the bloc calls....

abstract class LoginRepository<TData, TVars, TRequest extends OperationRequest<TData, dynamic>> {
  Future<Either<AuthFailure, GLoginData_login>> loginWithUsernameAndPassword({
    @required Username username,
    @required Password password,
  });
}

This repository is an abstract class where the method is implemented in the following class...

class LoginUser extends LoginRepository {
  
  @override
  Future<Either<AuthFailure, GLoginData_login>> loginWithUsernameAndPassword(
          {@required Username username, @required Password password}) =>
      _runQuery(username: username, password: password);

  Future<Either<AuthFailure, GLoginData_login>> _runQuery(
      {@required Username username, @required Password password}) async {

    final loginReq = GLoginReq(
      (b) => b
        ..vars.LoginInput.username = usernameStr
        ..vars.LoginInput.password = passwordStr,
    );
    try {
    return await GetIt.instance<Client>().request(loginReq).listen((response) {
      if (!response.loading && response.dataSource == DataSource.Link && 
         response.data != null) {
        GLoginData data = response.data;
        GLoginData_login login = data.login;
        return login;
      }

      if (response.linkException != null) {
        return response.graphqlErrors;
      }
    }).asFuture(); <------ I am marking it as a future so that it can be passed back

  } on Exception catch (e) {
  // Will need a created AuthException depending on our API and requirements
  if (e.toString() == 'ERROR_NO_ACCOUNT_MATCHES_DETAILS_GIVEN') {
    return left(const AuthFailure.invalidUsernameAndPaswordCombination());
  } else {
    return left(const AuthFailure.serverError());
  }
 }
}
}

I do receive the data from the serverising the client response. However in my bloc I cannot do anything with it as it just jumps out of the bloc after the loginWithUsernameAndPassword function completes.

How can I use the return value in my bloc, the whenComplete value line isn't working.

Thanks for any help you can provide.

Answer 1

just do:

either.fold(
   (l) => Something(),
   (r) => Something(),
);

If you have a function that returns the values then put the l or r into the function.