mediatr 0.2.1

Dart mediatr package. Central mediator that allows sending requests, and publishing events.

Dart mediator package

Pure dart package. No dependencies in flutter can be run both in flutter and dart API's.

Inspired by https://github.com/jbogard/MediatR

Create and send a request

 /// Create the request 
 class AddRequest extends IRequest<int> {
  final int i;

  AddRequest(this.i);
}

/// Create a request handler 
class AddRequestHandler extends IRequestHandler<AddRequest, int> {
  @override
  Future<int> call(AddRequest request) async {
    return request.i + 1;
  }
}
/// Register the handler to the mediator instance ( commonly stored as a singleton )
 final mediator = Mediator(Pipeline());

 mediator.registerHandler<AddRequest, int, AddRequestHandler>(
          () => AddRequestHandler(),
        );

/// Send the request through the mediator instance
final added = await mediator.send<AddRequest, int>(
          AddRequest(2),
        );
print(added); // prints 3

Publishing events

/// create an event extending IDomainEvent
class MyEvent extends IDomainEvent {
  @override
  String get name => 'MyEvent';
}

mediator.publish<MyEvent>(MyEvent());

Subscribe on events with functions

/// subscribe on mediator instance
var unsubscribeFunc = mediator.subscribeWithFunc<MyEvent>((event){
 print(event.name);
});

/// call the func returned to unsubscribe
unsubscribeFunc();

Subscribe on events with a class instance

class MyEventHandler extends IEventHandler<MyEvent> {
  @override
  Future<void> call(MyEvent event) {
    print(event);
  }
}
var eventHandler = MyEventHandler();

mediator.subscribe<MyEvent>(eventHandler);


/// call unsubscribe with the same instance to remove the handler.
mediator.unsubscribe<MyEvent>(eventHandler);

Adding a middleware for all requests

class LoggingBehavior extends IPipelineBehavior {
  @override
  Future process(IRequest request, RequestHandlerDelegate next) {
    print(request);
    return next(request);
  }
}

final mediator = Mediator(
  Pipeline()
    ..addMiddleware(
      LoggingBehavior(),
    ),
);