How to configure simple injector container and lifestylse in a MVC web app with WebAPI, WCF, SignalR and Background Task

Question

The simple injector documentation provides great examples on how to setup the container for WebRequest, Web API, WCF, ... but the examples are specific to one technology/lifest

Answer 1

I have to say, I stumble on a similar scenario some time ago, I ended up by sharing my configuration over my web API and signalR, but you need to implement a custom lifestyle for signalR since it's not based on web request.

specially in signalR you'll find some issues handling per-web-request dependencies in a Hub some of them are going to be null like httpContext.Current among others.

The solution:

You need a hybrid lifestyle between WebRequestLifestlye and either Lifestyle.Transient, Lifestyle.Singleton, or LifetimeScopeLifestyle. I ended up I finished using the decorator pattern, you may read this post and this other post.

my decorator

public class CommandLifetimeScopeDecorator : ICommandHandler
    {
        private readonly Func> _handlerFactory;
        private readonly Container _container;

        public CommandLifetimeScopeDecorator(
        Func> handlerFactory, Container container)
        {
            _handlerFactory = handlerFactory;
            _container = container;
        }

        public void Handle(T command)
        {
            using (_container.BeginLifetimeScope())
            {
                var handler = _handlerFactory(); // resolve scoped dependencies
                handler.Handle(command);
            }
        }

    }

    public interface ICommandHandler
    {
        void Handle(T command);
    }

I managed the dependencies using a hub activator for signalR

public class MyHubActivator : IHubActivator
    {
        private readonly Container _container;

        public MyHubActivator(Container container)
        {
            _container = container;
        }

        public IHub Create(HubDescriptor descriptor)
        {
            return _container.GetInstance(descriptor.HubType) as IHub;
        }
    }

a composite root file which is where you are going to handle your dependencies

public CompositRoot(Container container)
{
    _container = container;
}
public container Configure()
{
   // _container.Registerall container dependencies
   return _container;
}

then share your composite root configuration when you are bootstrapping your app

var compositRoot = new CompositRoot(simpleInjector.Container); //simple injector instance
compositRoot.Configure();

For signalR

GlobalHost.DependencyResolver.Register(typeof(IHubActivator), () => new MyHubActivator(compositRoot));

and you may reuse your configuration among other projects!

my two cents hope that helps!