Adding IView.Path and ViewContext.ExecutingPagePath

Fixes #1940

src/Microsoft.AspNet.Mvc.Core/Rendering/ViewEngine/IView.cs

@@ -5,8 +5,21 @@
 
 namespace Microsoft.AspNet.Mvc.Rendering
 {
+    /// <summary>
+    /// Specifies the contract for a view.
+    /// </summary>
     public interface IView
     {
+        /// <summary>
+        /// Gets the path of the view as resolved by the <see cref="IViewEngine"/>.
+        /// </summary>
+        string Path { get; }
+
+        /// <summary>
+        /// Asynchronously renders the view using the specified <paramref name="context"/>.
+        /// </summary>
+        /// <param name="context">The <see cref="ViewContext"/>.</param>
+        /// <returns>A <see cref="Task"/> that on completion renders the view.</returns>
         Task RenderAsync([NotNull] ViewContext context);
     }
 }

src/Microsoft.AspNet.Mvc.Core/ViewContext.cs

@@ -6,6 +6,9 @@
 
 namespace Microsoft.AspNet.Mvc
 {
+    /// <summary>
+    /// Context for view execution.
+    /// </summary>
     public class ViewContext : ActionContext
     {
         // We need a default FormContext if the user uses html <form> instead of an MvcForm
@@ -14,6 +17,13 @@ public class ViewContext : ActionContext
         private FormContext _formContext;
         private DynamicViewData _viewBag;
 
+        /// <summary>
+        /// Initializes a new instance of <see cref="ViewContext"/>.
+        /// </summary>
+        /// <param name="actionContext">The <see cref="ActionContext"/>.</param>
+        /// <param name="view">The <see cref="IView"/> being rendered.</param>
+        /// <param name="viewData">The <see cref="ViewDataDictionary"/>.</param>
+        /// <param name="writer">The <see cref="TextWriter"/> to render output to.</param>
         public ViewContext(
             [NotNull] ActionContext actionContext,
             [NotNull] IView view,
@@ -31,6 +41,13 @@ public class ViewContext : ActionContext
             ValidationMessageElement = "span";
         }
 
+        /// <summary>
+        /// Initializes a new instance of <see cref="ViewContext"/>.
+        /// </summary>
+        /// <param name="viewContext">The <see cref="ViewContext"/> to copy values from.</param>
+        /// <param name="view">The <see cref="IView"/> being rendered.</param>
+        /// <param name="viewData">The <see cref="ViewDataDictionary"/>.</param>
+        /// <param name="writer">The <see cref="TextWriter"/> to render output to.</param>
         public ViewContext(
             [NotNull] ViewContext viewContext,
             [NotNull] IView view,
@@ -49,6 +66,10 @@ public class ViewContext : ActionContext
             Writer = writer;
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="Mvc.FormContext"/> for the form element being rendered.
+        /// A default context is returned if no form is currently being rendered.
+        /// </summary>
         public virtual FormContext FormContext
         {
             get
@@ -62,6 +83,9 @@ public virtual FormContext FormContext
             }
         }
 
+        /// <summary>
+        /// Gets or sets a value that indicates whether client-side validation is enabled.
+        /// </summary>
         public bool ClientValidationEnabled { get; set; }
 
         /// <summary>
@@ -84,6 +108,9 @@ public virtual FormContext FormContext
         /// </summary>
         public string ValidationMessageElement { get; set; }
 
+        /// <summary>
+        /// Gets the dynamic view bag.
+        /// </summary>
         public dynamic ViewBag
         {
             get
@@ -97,12 +124,30 @@ public dynamic ViewBag
             }
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="IView"/> currently being rendered, if any.
+        /// </summary>
         public IView View { get; set; }
 
+        /// <summary>
+        /// Gets or sets the <see cref="ViewDataDictionary"/>.
+        /// </summary>
         public ViewDataDictionary ViewData { get; set; }
 
+        /// <summary>
+        /// Gets or sets the <see cref="TextWriter"/> used to write the output.
+        /// </summary>
         public TextWriter Writer { get; set; }
 
+        /// <summary>
+        /// Gets or sets the path of the view file currently being rendered.
+        /// </summary>
+        /// <remarks>
+        /// The rendering of a view may involve one or more files (e.g. _ViewStart, Layouts etc).
+        /// This property contains the path of the file currently being rendered.
+        /// </remarks>
+        public string ExecutingFilePath { get; set; }
+
         public FormContext GetFormContextForClientValidation()
         {
             return (ClientValidationEnabled) ? FormContext : null;

src/Microsoft.AspNet.Mvc.Razor/RazorView.cs

@@ -42,6 +42,12 @@ public class RazorView : IView
             IsPartial = isPartial;
         }
 
+        /// <inheritdoc />
+        public string Path
+        {
+            get { return RazorPage.Path; }
+        }
+
         /// <summary>
         /// Gets <see cref="IRazorPage"/> instance that the views executes on.
         /// </summary>
@@ -93,7 +99,9 @@ public virtual async Task RenderAsync([NotNull] ViewContext context)
             // The writer for the body is passed through the ViewContext, allowing things like HtmlHelpers
             // and ViewComponents to reference it.
             var oldWriter = context.Writer;
+            var oldFilePath = context.ExecutingFilePath;
             context.Writer = writer;
+            context.ExecutingFilePath = page.Path;
 
             try
             {
@@ -109,6 +117,7 @@ public virtual async Task RenderAsync([NotNull] ViewContext context)
             finally
             {
                 context.Writer = oldWriter;
+                context.ExecutingFilePath = oldFilePath;
                 writer.Dispose();
             }
         }
@@ -131,12 +140,21 @@ private async Task RenderViewStartAsync(ViewContext context)
             var viewStarts = _viewStartProvider.GetViewStartPages(RazorPage.Path);
 
             string layout = null;
-            foreach (var viewStart in viewStarts)
+            var oldFilePath = context.ExecutingFilePath;
+            try
+            {
+                foreach (var viewStart in viewStarts)
+                {
+                    context.ExecutingFilePath = viewStart.Path;
+                    // Copy the layout value from the previous view start (if any) to the current.
+                    viewStart.Layout = layout;
+                    await RenderPageCoreAsync(viewStart, context);
+                    layout = viewStart.Layout;
+                }
+            }
+            finally
             {
-                // Copy the layout value from the previous view start (if any) to the current.
-                viewStart.Layout = layout;
-                await RenderPageCoreAsync(viewStart, context);
-                layout = viewStart.Layout;
+                context.ExecutingFilePath = oldFilePath;
             }
 
             // Copy over interesting properties from the ViewStart page to the entry page.

test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/ViewEngineController.ViewWithPaths.txt

@@ -0,0 +1,21 @@
+<Layout>
+    /Views/ViewWithPaths/_Layout.cshtml
+    /Views/ViewWithPaths/Index.cshtml
+</Layout>
+
+<ViewStart>
+    Views\ViewWithPaths\_ViewStart.cshtml
+    /Views/ViewWithPaths/Index.cshtml
+</ViewStart>
+<Index>
+    /Views/ViewWithPaths/Index.cshtml
+    /Views/ViewWithPaths/Index.cshtml
+    <component>
+/Views/Shared/Components/ComponentForViewWithPaths/Default.cshtml
+/Views/Shared/Components/ComponentForViewWithPaths/Default.cshtml
+</component>
+    <Partial>
+/Views/ViewWithPaths/_Partial.cshtml
+/Views/ViewWithPaths/_Partial.cshtml
+</Partial>
+</Index>

test/Microsoft.AspNet.Mvc.FunctionalTests/ViewEngineTests.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.TestHost;
@@ -395,5 +396,21 @@ public async Task PartialsRenderedViaPartialAsync_CanRenderLayouts()
             // Assert
             Assert.Equal(expected, body.Trim());
         }
+
+        [Fact]
+        public async Task RazorView_SetsViewPathAndExecutingPagePath()
+        {
+            // Arrange
+            var expected = await GetType().GetTypeInfo().Assembly
+                .ReadResourceAsStringAsync("compiler/resources/ViewEngineController.ViewWithPaths.txt");
+            var server = TestServer.Create(_provider, _app);
+            var client = server.CreateClient();
+
+            // Act
+            var body = await client.GetStringAsync("http://localhost/ViewWithPaths");
+
+            // Assert
+            Assert.Equal(expected, body.Trim());
+        }
     }
 }

test/Microsoft.AspNet.Mvc.Razor.Test/RazorViewTest.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
@@ -83,6 +84,61 @@ public async Task RenderAsync_AsPartial_ActivatesViews_WithThePassedInViewContex
             Assert.Same(expectedWriter, viewContext.Writer);
         }
 
+        [Fact]
+        public async Task ViewContext_ExecutingPagePath_ReturnsPathOfRazorPageBeingExecuted()
+        {
+            // Arrange
+            var pagePath = "/my/view";
+            var paths = new List<string>();
+            var page = new TestableRazorPage(v =>
+            {
+                paths.Add(v.ViewContext.ExecutingFilePath);
+                Assert.Equal(pagePath, v.ViewContext.View.Path);
+            })
+            {
+                Path = pagePath
+            };
+
+            var viewStart = new TestableRazorPage(v =>
+            {
+                v.Layout = LayoutPath;
+                paths.Add(v.ViewContext.ExecutingFilePath);
+                Assert.Equal(pagePath, v.ViewContext.View.Path);
+            })
+            {
+                Path = "_ViewStart"
+            };
+
+            var layout = new TestableRazorPage(v =>
+            {
+                v.RenderBodyPublic();
+                paths.Add(v.ViewContext.ExecutingFilePath);
+                Assert.Equal(pagePath, v.ViewContext.View.Path);
+            })
+            {
+                Path = LayoutPath
+            };
+
+            var activator = Mock.Of<IRazorPageActivator>();
+            var viewEngine = new Mock<IRazorViewEngine>();
+            viewEngine.Setup(v => v.FindPage(It.IsAny<ActionContext>(), LayoutPath))
+                      .Returns(new RazorPageResult(LayoutPath, layout));
+            var view = new RazorView(viewEngine.Object,
+                                     activator,
+                                     CreateViewStartProvider(viewStart),
+                                     page,
+                                     isPartial: false);
+
+            var viewContext = CreateViewContext(view);
+            var expectedWriter = viewContext.Writer;
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Equal(new[] { "_ViewStart", pagePath, LayoutPath }, paths);
+        }
+
         [Fact]
         public async Task RenderAsync_AsPartial_ActivatesViews()
         {

test/WebSites/CompositeViewEngineWebSite/TestPartialView.cs

@@ -9,6 +9,8 @@ namespace CompositeViewEngineWebSite
 {
     public class TestPartialView : IView
     {
+        public string Path { get; set; }
+
         public async Task RenderAsync(ViewContext context)
         {
             await context.Writer.WriteLineAsync("world");

test/WebSites/CompositeViewEngineWebSite/TestView.cs

@@ -9,6 +9,8 @@ namespace CompositeViewEngineWebSite
 {
     public class TestView : IView
     {
+        public string Path { get; set; }
+
         public async Task RenderAsync(ViewContext context)
         {
             await context.Writer.WriteLineAsync("Content from test view");

test/WebSites/ModelBindingWebSite/Controllers/RoundtripController.cs

@@ -68,6 +68,8 @@ public Person Person(Person boundPerson)
 
         private sealed class TestView : IView
         {
+            public string Path { get; set; }
+
             public Task RenderAsync(ViewContext context)
             {
                 throw new NotImplementedException();

test/WebSites/RazorWebSite/Components/ComponentForViewWithPaths.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+
+namespace MvcSample.Web.Components
+{
+    [ViewComponent(Name = "ComponentForViewWithPaths")]
+    public class ComponentForViewWithPaths : ViewComponent
+    {
+        public IViewComponentResult Invoke()
+        {
+            return View();
+        }
+    }
+}

test/WebSites/RazorWebSite/Controllers/ViewWithPathsController.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+
+namespace RazorWebSite.Controllers
+{
+    public class ViewWithPathsController : Controller
+    {
+        [HttpGet("/ViewWithPaths")]
+        public IActionResult Index()
+        {
+            return View();
+        }
+    }
+}

test/WebSites/RazorWebSite/Views/Shared/Components/ComponentForViewWithPaths/Default.cshtml

@@ -0,0 +1,4 @@
+<component>
+@ViewContext.ExecutingFilePath
+@ViewContext.View.Path
+</component>

test/WebSites/RazorWebSite/Views/ViewWithPaths/Index.cshtml

@@ -0,0 +1,6 @@
+<Index>
+    @ViewContext.ExecutingFilePath
+    @ViewContext.View.Path
+    @Component.Invoke("ComponentForViewWithPaths")
+    @Html.Partial("_Partial")
+</Index>

test/WebSites/RazorWebSite/Views/ViewWithPaths/_Layout.cshtml

@@ -0,0 +1,5 @@
+<Layout>
+    @ViewContext.ExecutingFilePath
+    @ViewContext.View.Path
+</Layout>
+@RenderBody()

test/WebSites/RazorWebSite/Views/ViewWithPaths/_Partial.cshtml

@@ -0,0 +1,4 @@
+<Partial>
+@ViewContext.ExecutingFilePath
+@ViewContext.View.Path
+</Partial>