UseCallAdapter class

By annotating a method with @UseCallAdapter, you can specify a custom adapter class where you can adapt a call to another response wrapper

Usage

1. Create the call adapter by extending CallAdapter: pass in type parameters for the original call return type and adapted call return type. Note: your adapter subclass must accept a single type parameter(T), where T is the type of the unwrapped response from the original call. e.g. "UserResponse" in "Future"

class ResultCallAdapter<T> extends CallAdapter<Future<T>, Future<Result<T>>> {
  @override
  Future<Result<T>> adapt(Future<T> Function() call) async {
    try {
      final response = await call();
      return Success<T>(response);
    } catch (e) {
      return Error(e);
    }
  } 
}

2. Set the adapter on an API method or the entire API interface:

• To apply the adapter to an individual method, use @UseCallAdapter on the method:

@UseCallAdapter(ResultCallAdapter)
Future<Result<UserResponse>> fetchData();

• To apply it to all methods in an Api interface, pass the adapter to @RestApi:

@RestApi(callAdapter: ResultCallAdapter)
abstract class MyApiService {
  @GET('/data')
  Future<Result<UserResponse>> fetchData();
}