Fixes: #U4-1760 - allows a developer to set the default RenderMvcController on startup.

src/Umbraco.Tests/Routing/RenderRouteHandlerTests.cs

@@ -38,6 +38,8 @@ namespace Umbraco.Tests.Routing
 
         protected override void FreezeResolution()
         {
+            DefaultRenderMvcControllerResolver.Current = new DefaultRenderMvcControllerResolver(typeof(RenderMvcController));
+
             SurfaceControllerResolver.Current = new SurfaceControllerResolver(
                 PluginManager.Current.ResolveSurfaceControllers());
             UmbracoApiControllerResolver.Current = new UmbracoApiControllerResolver(

src/Umbraco.Web/Mvc/DefaultRenderMvcControllerResolver.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Web.Mvc;
+using Umbraco.Core;
+using Umbraco.Core.ObjectResolution;
+
+namespace Umbraco.Web.Mvc
+{
+    /// <summary>
+    /// A resolver used to resolve the default RenderMvcController that is used to render any front-end
+    /// Umbraco page when using MVC when there are no routes hijacked.
+    /// </summary>
+    public class DefaultRenderMvcControllerResolver : SingleObjectResolverBase<DefaultRenderMvcControllerResolver, Type>
+    {
+        /// <summary>
+        /// Constructor accepting the default RenderMvcController
+        /// </summary>
+        /// <param name="value"></param>
+        public DefaultRenderMvcControllerResolver(Type value)
+            : base(value)
+        {
+            ValidateType(value);
+        }
+
+        /// <summary>
+        /// Returns the Default RenderMvcController type
+        /// </summary>
+        /// <returns></returns>
+        public Type GetDefaultControllerType()
+        {
+            return Value;
+        }
+
+        /// <summary>
+        /// Returns an instance of the default controller instance.
+        /// </summary>
+        public RenderMvcController GetControllerInstance()
+        {
+            //try the dependency resolver, then the activator
+            var instance = DependencyResolver.Current.GetService(Value) ?? Activator.CreateInstance(Value);
+            var result = instance as RenderMvcController;
+            if (result == null)
+            {
+                throw new InvalidOperationException("Could not create an instance of " + Value + " for the default RenderMvcController");
+            }
+            return result;
+        }
+
+        /// <summary>
+        /// Sets the default RenderMvcController type
+        /// </summary>
+        /// <param name="controllerType"></param>
+        public void SetDefaultControllerType(Type controllerType)
+        {
+            ValidateType(controllerType);
+            Value = controllerType;
+        }
+
+        /// <summary>
+        /// Ensures that the type passed in is of type RenderMvcController
+        /// </summary>
+        /// <param name="type"></param>
+        private void ValidateType(Type type)
+        {
+            if (TypeHelper.IsTypeAssignableFrom<RenderMvcController>(type) == false)
+            {
+                throw new InvalidOperationException("The Type specified (" + type + ") is not of type " + typeof(RenderMvcController));
+            }
+        }
+
+    }
+}

src/Umbraco.Web/Mvc/RenderRouteHandler.cs

@@ -236,12 +236,13 @@ namespace Umbraco.Web.Mvc
 		/// <returns></returns>
 		internal virtual RouteDefinition GetUmbracoRouteDefinition(RequestContext requestContext, PublishedContentRequest publishedContentRequest)
 		{
-			var defaultControllerName = ControllerExtensions.GetControllerName<RenderMvcController>();
+		    var defaultControllerType = DefaultRenderMvcControllerResolver.Current.GetDefaultControllerType();
+            var defaultControllerName = ControllerExtensions.GetControllerName(defaultControllerType);
 			//creates the default route definition which maps to the 'UmbracoController' controller
 			var def = new RouteDefinition
 				{
 					ControllerName = defaultControllerName,
-					ControllerType = typeof(RenderMvcController),
+                    ControllerType = defaultControllerType,
 					PublishedContentRequest = publishedContentRequest,
 					ActionName = ((Route)requestContext.RouteData.Route).Defaults["action"].ToString(),
 					HasHijackedRoute = false
@@ -260,12 +261,12 @@ namespace Umbraco.Web.Mvc
 
 			//check if there's a custom controller assigned, base on the document type alias.
             var controllerType = _controllerFactory.GetControllerTypeInternal(requestContext, publishedContentRequest.PublishedContent.DocumentTypeAlias);
-            
+
 			//check if that controller exists
 		    if (controllerType != null)
 		    {
                 //ensure the controller is of type 'RenderMvcController'
-		        if (controllerType.IsSubclassOf(typeof (RenderMvcController)))
+                if (TypeHelper.IsTypeAssignableFrom<RenderMvcController>(controllerType))
 		        {
 		            //set the controller and name to the custom one
 		            def.ControllerType = controllerType;

src/Umbraco.Web/Mvc/UmbracoControllerFactory.cs

@@ -29,8 +29,11 @@ namespace Umbraco.Web.Mvc
         /// <param name="requestContext">The request context.</param><param name="controllerName">The name of the controller.</param>
         public virtual IController CreateController(RequestContext requestContext, string controllerName)
         {
-            Type controllerType = GetControllerType(requestContext, controllerName) ??
-                                  _innerFactory.GetControllerType(requestContext, ControllerExtensions.GetControllerName(typeof(RenderMvcController)));
+            var controllerType = GetControllerType(requestContext, controllerName) ??
+                                 _innerFactory.GetControllerType(
+                                     requestContext,
+                                     ControllerExtensions.GetControllerName(
+                                         DefaultRenderMvcControllerResolver.Current.GetDefaultControllerType()));
 
             return _innerFactory.GetControllerInstance(requestContext, controllerType);
         }

src/Umbraco.Web/Umbraco.Web.csproj

@@ -330,6 +330,7 @@
     <Compile Include="BaseRest\RestExtensionMethodAttribute.cs" />
     <Compile Include="BaseRest\RestExtensionMethodInfo.cs" />
     <Compile Include="ContextualPublishedCacheExtensions.cs" />
+    <Compile Include="Mvc\DefaultRenderMvcControllerResolver.cs" />
     <Compile Include="PublishedCache\ContextualPublishedContentCache.cs" />
     <Compile Include="PublishedCache\ContextualPublishedCacheOfT.cs" />
     <Compile Include="PublishedCache\ContextualPublishedCache.cs" />

src/Umbraco.Web/UmbracoApplication.cs

@@ -8,11 +8,30 @@ using System.Web.Hosting;
 using System.Web.Mvc;
 using Umbraco.Core;
 using Umbraco.Core.Logging;
+using Umbraco.Web.Mvc;
 using Umbraco.Web.Routing;
 using umbraco.businesslogic;
 
 namespace Umbraco.Web
 {
+    public class CustomRenderController : RenderMvcController
+    {
+        public override ActionResult Index(Models.RenderModel model)
+        {
+            HttpContext.Response.ContentType = "text/plain";
+            return base.Index(model);
+        }
+    }
+
+    public class CustomApplicationEventHandler : ApplicationEventHandler
+    {
+        protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
+        {
+            DefaultRenderMvcControllerResolver.Current.SetDefaultControllerType(typeof(CustomRenderController));
+            base.ApplicationStarting(umbracoApplication, applicationContext);
+        }
+    }
+
 	/// <summary>
 	/// The Umbraco global.asax class
 	/// </summary>

src/Umbraco.Web/WebBootManager.cs

@@ -235,6 +235,9 @@ namespace Umbraco.Web
         {
             base.InitializeResolvers();
 
+            //set the default RenderMvcController
+            DefaultRenderMvcControllerResolver.Current = new DefaultRenderMvcControllerResolver(typeof(RenderMvcController));
+
             //Override the ServerMessengerResolver to set a username/password for the distributed calls
             ServerMessengerResolver.Current.SetServerMessenger(new DefaultServerMessenger(() =>
             {