IoC: Castle Windsor and WebAPI

Question

I have an MVC4 site using Castle Windsor that I want to add some WebAPI calls to, so I start digging around a little bit on the interwebs.

Now I don\'t know the ins

Answer 1

Existing Castle Windsor MVC configuration

Assuming you have MVC and Castle Windsor setup similarly to the Castle Windsor MVC tutorial, adding IoC to get Web API controllers to utilize dependency injection is very simple with Mark Seemann's post (note that he explains why not to use IDependencyResolver).

From the Castle Windsor tutorial you should have something like this in Global.asax.cs.

    private static IWindsorContainer container;

    protected void Application_Start()
    {
        //... MVC / Web API routing etc.
        BootStrapper bs = new BootStrapper();
        container = bs.ConfigureCastleWindsorMVC();
    }

BootStrapper.ConfigureCastleWindsorMVC() snip

        IWindsorContainer container = new WindsorContainer()
            .Install(
                new LoggerInstaller()
                //...,
                , new ControllersInstaller()
            );

        var controllerFactory = new WindsorControllerFactory(container.Kernel);
        ControllerBuilder.Current.SetControllerFactory(controllerFactory);
        return container;

Required changes

From Mark Seemann's post you need to get into Web API's entry point (Composition Root) through the IHttpControllerActivator. Here's his adapter implementation which you need.

public class WindsorCompositionRoot : IHttpControllerActivator
{
    private readonly IWindsorContainer container;

    public WindsorCompositionRoot(IWindsorContainer container)
    {
        this.container = container;
    }

    public IHttpController Create(HttpRequestMessage request,
        HttpControllerDescriptor controllerDescriptor, Type controllerType)
    {
        var controller =
            (IHttpController)this.container.Resolve(controllerType);

        request.RegisterForDispose(
            new Release(() => this.container.Release(controller)));

        return controller;
    }

    private class Release : IDisposable
    {
        private readonly Action release;

        public Release(Action release) { this.release = release; }

        public void Dispose()
        {
            this.release();
        }
    }
}

With the IHttpControllerActivator adapter and the MVC Castle Windsor container implementation, you just need to configure it in the Global.asax.cs (or in BootStrapper if you used that). It has to be after the MVC initialization since the MVC initialization has all of the installers.

    private static IWindsorContainer container;

    protected void Application_Start()
    {
        // MVC / Web API routing etc.
        BootStrapper bs = new BootStrapper();
        container = bs.ConfigureCastleWindsorMVC();
        // Web API Castle Windsor ++ ADD THIS ++
        GlobalConfiguration.Configuration.Services.Replace(
            typeof(IHttpControllerActivator),
            new WindsorCompositionRoot(container));
    }

Final Result:

The Web API controllers can use your injected dependencies the same as your MVC controllers.

public class TestController : ApiController
{
    private readonly ITestService TestService;

    public TestController(ITestService testService)
    {
        this.TestService = testService;
    }

    // GET api/<controller>
    public IEnumerable<string> Get()
    {
        return TestService.GetSomething();
        //return new string[] { "value1", "value2" };
    }
}

Answer 2

The following sample project gave me the answer I was looking for. It uses Castle Windsor for dependency injection. I was able to use MVC Controllers alongside Web API controllers on the same Application.

mirajavora / WebAPISample

---

Here's the post detailing it:

Getting Started with ASP.NET Web API

Answer 3

First as Iko stated you need to create a class that implements IHttpControllerActivator.

Then in ContainerBootstrapper in Bootstrap() add the following Replace the default with the one implemented:

 //This will help in creating Web api with Dependency injection
 GlobalConfiguration.Configuration.Services.Replace(
 typeof(IHttpControllerActivator),
 new WindsorCompositionRoot(container));

Lastly which is not mentioned here and it didn't work for me without it that you should add the following in you implemented IWindsorInstaller service inside install() :

container.Register(
    Classes.FromThisAssembly()
    .BasedOn<ApiController>()
    .LifestyleTransient()    
);

Answer 4

In order to use Windsor with webapi follow http://blog.ploeh.dk/2012/10/03/DependencyInjectioninASP.NETWebAPIwithCastleWindsor/ (BEH: fixed link)

Read also Castle Windsor/DelegatingHandler/IPrincipal Dependency Injection (DI)/Inversion of Control (IoC) in ASP.NET Web API

You can use webapi and MVC controllers in the same app (I prefer to keep it separate) but routing and controllers factory are different and you have to set up two different configuration and handle routing overlaps... For MVC & Windsor you can find a great