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Windsor Integration

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By enabling Windsor Container integration, your controllers, filters and ViewComponents might request dependencies or configurations that can be satisfied by the container, thus leading your design to a loosely coupled state.

Warning

Once the integration is set you must register controllers and ViewComponents as ordinary container components. Filters can optionally be registered. To look up a ViewComponent on the view you must use the key used to register the component on the container instead of the ViewComponent name.

Necessary assemblies on the web project

Make your web project reference the following assemblies:

Web.config

Use the useWindsorIntegration attribute: 


<?xml version="1.0" ?> 
<configuration>

    <configSections>
        <section name="monorail"
                 type="Castle.MonoRail.Engine.Configuration.MonoRailSectionHandler, Castle.MonoRail.Engine" />
        <section name="castle"
                 type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />
    </configSections>

    <monorail useWindsorIntegration="true">
        <viewEngine 
            viewPathRoot="views" 
            customEngine="Castle.MonoRail.Framework.Views.NVelocity.NVelocityViewEngine, Castle.MonoRail.Framework.Views.NVelocity" />
    </monorail>

    <castle>

      <!-- component and facilities configuration goes here -->

    </castle>

</configuration>

Global.asax

You must make your container available to the web application. The best place for it is the global.asax: 


<%@ Application Inherits="YourApp.Web.MyGlobalApplication"  %>

MyGlobalApplication.cs: 


namespace YourApp.Web
{
    using System;
    using System.Web;

    using Castle.Windsor;
    using Castle.ActiveRecord;


    public class MyGlobalApplication : HttpApplication, IContainerAccessor
    {
        private static WebAppContainer container;

        public void Application_OnStart()
        {
            container = new WebAppContainer();
        }

        public void Application_OnEnd() 
        {
            container.Dispose();
        }

        public IWindsorContainer Container
        {
            get { return container; }
        }
    }
}

Container set up

You must register a facility named RailsFacility. It ensures that the lifestyle of each controller is set to Transient - as using the default, singleton, would be a terrible mistake - and register each component/controller on the ControllerTree.

Quick Note

Also note that from now on, your controllers, view components and optionally the filters are standard components, and they need to be registered on the container. 


namespace YourApp.Web
{
    using System;

    using YourApp.Web.Controllers;

    using Castle.Model.Resource;
    using Castle.Windsor.Configuration.Interpreters;
    using Castle.MonoRail.WindsorExtension;

    public class WebAppContainer : WindsorContainer
    {
        public WebAppContainer() : base(new XmlInterpreter( new ConfigResource() ))
        {
            RegisterFacilities();
            RegisterComponents();
        }

        protected void RegisterFacilities()
        {
            AddFacility( "rails", new RailsFacility() );
        }

        protected void RegisterComponents()
        {
            AddComponent( "home.controller", typeof(HomeController) );
        }
    }
}

Obviously you can decide to register the facility and the components directly on the configuration file. The approach above is just a suggestion.

Benefits

Once the integration is set you can take advantage of all the benefits offered by an Inversion of control container.

Example

Suppose you have a controller that receives files uploads. Where should it store the files? Make it configurable.

On the controller: 


public class ImageGalleryController : Controller
{
    ...

    public ImageGalleryController(String imageDirectory)
    {
        this.imageDirectory = imageDirectory;
    }

    ...
}

Let's assume that this controller was registered on the container with the key imagegallery.controller. On the configuration section: 


<castle>

  <components>

    <component id="imagegallery.controller">
      <parameters>
        <imageDirectory>C:\mytempdir\safedir</imageDirectory>
      </parameters>
    </component>

  <components>

</castle>

Your controller could assume a default directory and allow it to be overriden as well: 


public class ImageGalleryController : Controller
{
    private String imageDirectory = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);

    public ImageGalleryController()
    {
    }

    public string ImageDirectory
    {
        get { return imageDirectory; }
        set { imageDirectory = value; }
    }

    ...
}

The previous configuration for the component still valid. But now it is optional as the controller can live without it.

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