Castle Windsor

For WebApi Projects

• Create a stasndard WebApi project with Visual Studio
• Add Castle.Core with Nuget
• Create an installer for the controllers. This will search for all WebApi controllers

public class ControllersInstaller : IWindsorInstaller
{
    public void Install(
    	IWindsorContainer container, 
    	IConfigurationStore store)
    {
        container.Register(
            Classes.
                FromThisAssembly().
                BasedOn<IHttpController>(). //Web API
                If(c => c.Name.EndsWith("Controller")).
                LifestyleTransient());
    }
}

• Prepare a class to contain all the needed initializations (to avoid putting garbage inside the Global.asax). This will search for all assemblies inside the application bin directory with an AssemblyFilter.

public class WindsorConfig
{
    private static IWindsorContainer _container;
    public static IWindsorContainer Container { get { return _container; } }

    public static void RegisterCastleWindsor()
    {
        _container = new WindsorContainer();

        string path = new Uri(
        	Path.GetDirectoryName(
        		Assembly.GetExecutingAssembly().GetName().CodeBase)).
        	AbsolutePath;
        var filter = new AssemblyFilter(path)
	        .FilterByAssembly(a => !a.IsDynamic);

        _container.Kernel.Resolver.
            AddSubResolver(new CollectionResolver(_container.Kernel));
        _container.AddFacility<TypedFactoryFacility>();

        _container.AddFacility<LoggingFacility>(f =>
            f.LogUsing(LoggerImplementation.Log4net));

        _container.Install(FromAssembly.InDirectory(filter));

        GlobalConfiguration.Configuration.Services.Replace(
            typeof(IHttpControllerActivator),
            new WindsorWebApiControllerActivator(_container));
    }
}

• Prepare an activator for the WebApi controllers

public class WindsorWebApiControllerActivator : IHttpControllerActivator
{
    private readonly IWindsorContainer _container;

    public WindsorWebApiControllerActivator(IWindsorContainer container)
    {
        _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)
        {
            _release = release;
        }

        public void Dispose()
        {
            _release();
        }
    }
}

• Modify the application_start in Global.asax to initialize Castle

public class WebApiApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        WindsorConfig.RegisterCastleWindsor();
        ...
   	}
   	...
}