Episerver CMS: Route requests to alternate controllers and actions based on page properties.

CustomRoutingResolver.cs

using EPiServer.Core;
using EPiServer.Framework;
using EPiServer.Framework.Initialization;
using EPiServer.ServiceLocation;
using EPiServer.Web;
using System.Linq;
using System.Web;

namespace BlendInteractive.Business
{
    /// <summary>
    /// Checks a property of the rendering page for specified custom controller/action. This enables
    /// "one-off" and "application-ish" pages to be an instance of an existing page type, but use a
    /// different controller, action, or combination of the two.
    /// </summary>
    [InitializableModule]
    [ModuleDependency(typeof(EPiServer.Web.InitializationModule))]
    public class CustomRoutingResolver : IInitializableModule
    {
        /// <summary>
        /// The name of the property which holds the custom controller value
        /// </summary>
        private const string controllerPropertyName = "CustomController";

        /// <summary>
        /// The name of the property which holds the custom action value
        /// </summary>
        private const string actionPropertyName = "CustomAction";

        /// <summary>
        /// Only execute for these page types
        /// </summary>
        private string[] allowedTypes = new[] { "StandardPage" };

        public void Initialize(InitializationEngine context)
        {
            ServiceLocator.Current.GetInstance<TemplateResolver>().TemplateResolved += (object sender, TemplateResolverEventArgs e) =>
            {
                // This method gets called when trying to resolve a URL. In some cases, the context will be null.
                if (HttpContext.Current == null)
                {
                    return;
                }

                // If it's not a page, abandon.
                if (!(e.ItemToRender is PageData))
                {
                    return;
                }

                var page = (PageData)e.ItemToRender;

                // If it's not an allowed type, abandon.
                if(!allowedTypes.Contains(page.PageTypeName))
                {
                    return;
                }

                // Handle custom controller assignment
                if (page.GetPropertyValue(controllerPropertyName) != null)
                {
                    var customControllerValue = page.GetPropertyValue(controllerPropertyName).Trim();

                    // Form the name of the desired controller
                    if (!customControllerValue.ToLower().EndsWith("controller"))
                    {
                        customControllerValue = customControllerValue + "Controller";
                    }

                    // Attempt to get that controller from the list of supported templates
                    var controller = e.SupportedTemplates.FirstOrDefault(t => t.Name.ToLower() == customControllerValue.ToLower());
                    if (controller != null)
                    {
                        e.SelectedTemplate = controller;
                    }
                }

                // Handle custom action assignment
                if (page.GetPropertyValue(actionPropertyName) != null)
                {
                    var customActionValue = page.GetPropertyValue(actionPropertyName).Trim();
                    HttpContext.Current.Request.RequestContext.RouteData.Values["action"] = customActionValue;

                    // Note that we have no way of verifying the action actually exists...
                }
            };
        }

        public void Preload(string[] parameters)
        {
        }

        public void Uninitialize(InitializationEngine context)
        {
            
        }
    }
}