Lots of notes, removes data tokens,

src/Umbraco.Web.Common/Controllers/RenderController.cs

@@ -0,0 +1,99 @@
+using System;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.ViewEngines;
+using Microsoft.Extensions.Logging;
+using Umbraco.Core;
+using Umbraco.Core.Models.PublishedContent;
+using Umbraco.Web.Common.Filters;
+using Umbraco.Web.Common.Routing;
+using Umbraco.Web.Models;
+using Umbraco.Web.Routing;
+
+namespace Umbraco.Web.Common.Controllers
+{
+
+    /// <summary>
+    /// Represents the default front-end rendering controller.
+    /// </summary>
+    [TypeFilter(typeof(ModelBindingExceptionFilter))]
+    public class RenderController : UmbracoController, IRenderController
+    {
+        private readonly ILogger<RenderController> _logger;
+        private readonly ICompositeViewEngine _compositeViewEngine;
+        private UmbracoRouteValues _routeValues;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RenderController"/> class.
+        /// </summary>
+        public RenderController(ILogger<RenderController> logger, ICompositeViewEngine compositeViewEngine)
+        {
+            _logger = logger;
+            _compositeViewEngine = compositeViewEngine;
+        }
+
+        /// <summary>
+        /// Gets the current content item.
+        /// </summary>
+        protected IPublishedContent CurrentPage => UmbracoRouteValues.PublishedContent;
+
+        /// <summary>
+        /// Gets the <see cref="UmbracoRouteValues"/>
+        /// </summary>
+        protected UmbracoRouteValues UmbracoRouteValues
+        {
+            get
+            {
+                if (_routeValues != null)
+                {
+                    return _routeValues;
+                }
+
+                if (!ControllerContext.RouteData.Values.TryGetValue(Core.Constants.Web.UmbracoRouteDefinitionDataToken, out var def))
+                {
+                    throw new InvalidOperationException($"No route value found with key {Core.Constants.Web.UmbracoRouteDefinitionDataToken}");
+                }
+
+                _routeValues = (UmbracoRouteValues)def;
+                return _routeValues;
+            }
+        }
+
+        /// <summary>
+        /// Ensures that a physical view file exists on disk.
+        /// </summary>
+        /// <param name="template">The view name.</param>
+        protected bool EnsurePhsyicalViewExists(string template)
+        {
+            ViewEngineResult result = _compositeViewEngine.FindView(ControllerContext, template, false);
+            if (result.View != null)
+            {
+                return true;
+            }
+
+            _logger.LogWarning("No physical template file was found for template {Template}", template);
+            return false;
+        }
+
+        /// <summary>
+        /// Gets an action result based on the template name found in the route values and a model.
+        /// </summary>
+        /// <typeparam name="T">The type of the model.</typeparam>
+        /// <param name="model">The model.</param>
+        /// <returns>The action result.</returns>
+        /// <exception cref="InvalidOperationException">If the template found in the route values doesn't physically exist and exception is thrown</exception>
+        protected IActionResult CurrentTemplate<T>(T model)
+        {
+            if (EnsurePhsyicalViewExists(UmbracoRouteValues.TemplateName) == false)
+            {
+                throw new InvalidOperationException("No physical template file was found for template " + UmbracoRouteValues.TemplateName);
+            }
+
+            return View(UmbracoRouteValues.TemplateName, model);
+        }
+
+        /// <summary>
+        /// The default action to render the front-end view.
+        /// </summary>
+        public virtual IActionResult Index() => CurrentTemplate(new ContentModel(CurrentPage));
+    }
+}