Add ITagHelperComponentManager (#6302)

Addresses #6282

src/Microsoft.AspNetCore.Mvc.Razor/DependencyInjection/MvcRazorMvcCoreBuilderExtensions.cs

@@ -8,6 +8,7 @@ using Microsoft.AspNetCore.Mvc.Razor;
 using Microsoft.AspNetCore.Mvc.Razor.Compilation;
 using Microsoft.AspNetCore.Mvc.Razor.Extensions;
 using Microsoft.AspNetCore.Mvc.Razor.Internal;
+using Microsoft.AspNetCore.Mvc.Razor.TagHelpers;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -187,6 +188,9 @@ namespace Microsoft.Extensions.DependencyInjection
             services.TryAddSingleton<ITagHelperActivator, DefaultTagHelperActivator>();
             services.TryAddSingleton<ITagHelperFactory, DefaultTagHelperFactory>();
 
+            // TagHelperComponents manager
+            services.TryAddScoped<ITagHelperComponentManager, TagHelperComponentManager>();
+
             // Consumed by the Cache tag helper to cache results across the lifetime of the application.
             services.TryAddSingleton<IMemoryCache, MemoryCache>();
         }

src/Microsoft.AspNetCore.Mvc.Razor/Internal/TagHelperComponentManager.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// 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 Microsoft.AspNetCore.Mvc.Razor.TagHelpers;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Internal
+{
+    /// <summary>
+    /// The default implementation of the <see cref="ITagHelperComponentManager"/>.
+    /// </summary>
+    public class TagHelperComponentManager : ITagHelperComponentManager
+    {
+        /// <summary>
+        /// Creates a new <see cref="TagHelperComponentManager"/>.
+        /// </summary>
+        /// <param name="tagHelperComponents">The collection of <see cref="ITagHelperComponent"/>s.</param>
+        public TagHelperComponentManager(IEnumerable<ITagHelperComponent> tagHelperComponents)
+        {
+            if (tagHelperComponents == null)
+            {
+                throw new ArgumentNullException(nameof(tagHelperComponents));
+            }
+
+            Components = new List<ITagHelperComponent>(tagHelperComponents);
+        }
+
+        /// <inheritdoc />
+        public ICollection<ITagHelperComponent> Components { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/TagHelpers/BodyTagHelper.cs

@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System.Collections.Generic;
 using System.ComponentModel;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Microsoft.Extensions.Logging;
@@ -18,10 +17,11 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
         /// <summary>
         /// Creates a new <see cref="BodyTagHelper"/>.
         /// </summary>
-        /// <param name="components">The list of <see cref="ITagHelperComponent"/>.</param>
+        /// <param name="manager">The <see cref="ITagHelperComponentManager"/> which contains the collection
+        /// of <see cref="ITagHelperComponent"/>s.</param>
         /// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
-        public BodyTagHelper(IEnumerable<ITagHelperComponent> components, ILoggerFactory loggerFactory)
+        public BodyTagHelper(ITagHelperComponentManager manager, ILoggerFactory loggerFactory)
-            : base(components, loggerFactory)
+            : base(manager, loggerFactory)
         {
         }
     }

src/Microsoft.AspNetCore.Mvc.Razor/TagHelpers/HeadTagHelper.cs

@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System.Collections.Generic;
 using System.ComponentModel;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Microsoft.Extensions.Logging;
@@ -18,10 +17,11 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
         /// <summary>
         /// Creates a new <see cref="HeadTagHelper"/>.
         /// </summary>
-        /// <param name="components">The list of <see cref="ITagHelperComponent"/>.</param>
+        /// <param name="manager">The <see cref="ITagHelperComponentManager"/> which contains the collection
+        /// of <see cref="ITagHelperComponent"/>s.</param>
         /// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
-        public HeadTagHelper(IEnumerable<ITagHelperComponent> components, ILoggerFactory loggerFactory)
+        public HeadTagHelper(ITagHelperComponentManager manager, ILoggerFactory loggerFactory)
-            : base(components, loggerFactory)
+            : base(manager, loggerFactory)
         {
         }
     }

src/Microsoft.AspNetCore.Mvc.Razor/TagHelpers/ITagHelperComponentManager.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
+{
+    /// <summary>
+    /// An implementation of this interface provides the collection of <see cref="ITagHelperComponent"/>s
+    /// that will be used by <see cref="TagHelperComponentTagHelper"/>s.
+    /// </summary>
+    public interface ITagHelperComponentManager
+    {
+        /// <summary>
+        /// Gets the collection of <see cref="ITagHelperComponent"/>s that will be used by
+        /// <see cref="TagHelperComponentTagHelper"/>s.
+        /// </summary>
+        ICollection<ITagHelperComponent> Components { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/TagHelpers/TagHelperComponentTagHelper.cs

@@ -11,6 +11,10 @@ using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
 {
+    /// <summary>
+    /// Initializes and processes the <see cref="ITagHelperComponent"/>s added to the 
+    /// <see cref="ITagHelperComponentManager.Components"/> in the specified order.
+    /// </summary>
     public abstract class TagHelperComponentTagHelper : TagHelper
     {
         private readonly ILogger _logger;
@@ -18,16 +22,21 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
         private IEnumerable<ITagHelperComponent> _components;
 
         /// <summary>
-        /// Creates a new <see cref="TagHelperComponentTagHelper"/>.
+        /// Creates a new <see cref="TagHelperComponentTagHelper"/> and orders the 
+        /// the collection of <see cref="ITagHelperComponent"/>s in <see cref="ITagHelperComponentManager.Components"/>.
         /// </summary>
-        /// <param name="components">The list of <see cref="ITagHelperComponent"/>.</param>
+        /// <param name="manager">The <see cref="ITagHelperComponentManager"/> which contains the collection
+        /// of <see cref="ITagHelperComponent"/>s.</param>
         /// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
-        public TagHelperComponentTagHelper(IEnumerable<ITagHelperComponent> components,
+        /// <remarks>The <see cref="ITagHelperComponentManager.Components"/> are ordered after the 
+        /// creation of the <see cref="ITagHelperComponentManager"/> to position the <see cref="ITagHelperComponent"/>s
+        /// added from controllers and views correctly.</remarks>
+        public TagHelperComponentTagHelper(ITagHelperComponentManager manager,
             ILoggerFactory loggerFactory)
         {
-            if (components == null)
+            if (manager == null)
             {
-                throw new ArgumentNullException(nameof(components));
+                throw new ArgumentNullException(nameof(manager));
             }
 
             if (loggerFactory == null)
@@ -35,14 +44,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 throw new ArgumentNullException(nameof(loggerFactory));
             }
 
-            _components = components;
+            _components = manager.Components.OrderBy(p => p.Order).ToArray();
             _logger = loggerFactory.CreateLogger(GetType());
         }
 
         /// <inheritdoc />
         public override void Init(TagHelperContext context)
         {
-            _components = _components.OrderBy(p => p.Order);
             foreach (var component in _components)
             {
                 component.Init(context);

test/Microsoft.AspNetCore.Mvc.FunctionalTests/TagHelperComponentTagHelperTest.cs

@@ -61,6 +61,30 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
 
+#if GENERATE_BASELINES
+            ResourceFile.UpdateFile(_resourcesAssembly, outputFile, expectedContent, responseContent);
+#else
+            Assert.Equal(expectedContent, responseContent, ignoreLineEndingDifferences: true);
+#endif
+        }
+
+        [Fact]
+        public async Task AddTestTagHelperComponent_FromController()
+        {
+            // Arrange
+            var url = "http://localhost/AddTagHelperComponent/AddComponent";
+            var request = new HttpRequestMessage(HttpMethod.Get, url);
+            var outputFile = "compiler/resources/RazorWebSite.AddTagHelperComponent.AddComponent.html";
+            var expectedContent =
+                await ResourceFile.ReadResourceAsync(_resourcesAssembly, outputFile, sourceFile: false);
+
+            // Act
+            var response = await Client.SendAsync(request);
+            var responseContent = await response.Content.ReadAsStringAsync();
+
+            // Assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
 #if GENERATE_BASELINES
             ResourceFile.UpdateFile(_resourcesAssembly, outputFile, expectedContent, responseContent);
 #else

test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/RazorWebSite.AddTagHelperComponent.AddComponent.html

@@ -0,0 +1,6 @@
+<head inject>
+Hello from Head Tag Helper Component
+<script>'This was injected!!'</script></head>
+<body inject>
+Hello from Body Tag Helper Component
+Processed TagHelperComponent added from controller.<script>'This was injected!!'</script>Processed TagHelperComponent added from view.</body>

test/Microsoft.AspNetCore.Mvc.Razor.Test/TagHelpers/TagHelperComponentTagHelperTest.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.Razor.Internal;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -27,7 +28,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 uniqueId: "test");
 
             var incrementer = 0;
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
             {
                 new CallbackTagHelperComponent(
                     order: 2,
@@ -53,7 +54,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                         incrementer++;
                     },
                     processAsyncCallback: null),
-            }, NullLoggerFactory.Instance);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, NullLoggerFactory.Instance);
 
             // Act
             testTagHelperComponentTagHelper.Init(tagHelperContext);
@@ -80,7 +83,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                     new DefaultTagHelperContent()));
 
             var incrementer = 0;
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
             {
                 new CallbackTagHelperComponent(
                     order: 2,
@@ -106,7 +109,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                         Assert.Equal(0, incrementer);
                         incrementer++;
                     }),
-            }, NullLoggerFactory.Instance);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, NullLoggerFactory.Instance);
 
             // Act
             testTagHelperComponentTagHelper.Init(tagHelperContext);
@@ -133,10 +138,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
                     new DefaultTagHelperContent()));
 
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new[]
             {
                 new TestTagHelperComponent()
-            }, NullLoggerFactory.Instance);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, NullLoggerFactory.Instance);
 
             // Act
             testTagHelperComponentTagHelper.Init(tagHelperContext);
@@ -162,16 +169,51 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
                     new DefaultTagHelperContent()));
 
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
             {
                 new TestTagHelperComponent()
-            }, NullLoggerFactory.Instance);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, NullLoggerFactory.Instance);
 
             // Act
             await testTagHelperComponentTagHelper.ProcessAsync(tagHelperContext, output);
 
             // Assert           
-            Assert.Equal("Processed", output.PostContent.GetContent());
+            Assert.Equal("Processed1", output.PostContent.GetContent());
+        }
+
+        [Fact]
+        public async Task ProcessAsync_InvokesTagHelperComponentProcessAsync_WithAddedTagHelperComponents()
+        {
+            // Arrange
+            var tagHelperContext = new TagHelperContext(
+                "head",
+                allAttributes: new TagHelperAttributeList(
+                    Enumerable.Empty<TagHelperAttribute>()),
+                items: new Dictionary<object, object>(),
+                uniqueId: "test");
+
+            var output = new TagHelperOutput(
+                "head",
+                attributes: new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
+                    new DefaultTagHelperContent()));
+
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
+            {
+                new TestTagHelperComponent()
+            });
+
+            testTagHelperComponentManager.Components.Add(new TestAddTagHelperComponent(0));
+            testTagHelperComponentManager.Components.Add(new TestAddTagHelperComponent(2));
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, NullLoggerFactory.Instance);
+
+            // Act
+            await testTagHelperComponentTagHelper.ProcessAsync(tagHelperContext, output);
+
+            // Assert           
+            Assert.Equal("Processed0Processed1Processed2", output.PostContent.GetContent());
         }
 
         [Fact]
@@ -193,10 +235,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
                     new DefaultTagHelperContent()));
 
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
             {
                 new TestTagHelperComponent()
-            }, loggerFactory);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, loggerFactory);
 
             // Act
             testTagHelperComponentTagHelper.Init(tagHelperContext);
@@ -224,10 +268,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
                 getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
                     new DefaultTagHelperContent()));
 
-            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(new []
+            var testTagHelperComponentManager = new TagHelperComponentManager(new []
             {
                 new TestTagHelperComponent()
-            }, loggerFactory);
+            });
+
+            var testTagHelperComponentTagHelper = new TestTagHelperComponentTagHelper(testTagHelperComponentManager, loggerFactory);
 
             // Act
             await testTagHelperComponentTagHelper.ProcessAsync(tagHelperContext, output);
@@ -239,9 +285,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
         private class TestTagHelperComponentTagHelper : TagHelperComponentTagHelper
         {
             public TestTagHelperComponentTagHelper(
-                IEnumerable<ITagHelperComponent> components,
+                ITagHelperComponentManager manager,
                 ILoggerFactory loggerFactory)
-                : base(components, loggerFactory)
+                : base(manager, loggerFactory)
             {
             }
         }
@@ -284,7 +330,29 @@ namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers
 
             public Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
             {
-                output.PostContent.AppendHtml("Processed");
+                output.PostContent.AppendHtml("Processed1");
+                return Task.CompletedTask;
+            }
+        }
+
+        private class TestAddTagHelperComponent : ITagHelperComponent
+        {
+            private int _order;
+
+            public TestAddTagHelperComponent(int order)
+            {
+                _order = order;
+            }
+
+            public int Order => _order;
+
+            public void Init(TagHelperContext context)
+            {
+            }
+
+            public Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
+            {
+                output.PostContent.AppendHtml("Processed" + Order);
                 return Task.CompletedTask;
             }
         }

test/WebSites/RazorWebSite/Controllers/AddTagHelperComponentController.cs

@@ -0,0 +1,24 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Razor.TagHelpers;
+
+namespace RazorWebSite.Controllers
+{
+    public class AddTagHelperComponentController : Controller
+    {
+        private readonly ITagHelperComponentManager _tagHelperComponentManager;
+
+        public AddTagHelperComponentController(ITagHelperComponentManager tagHelperComponentManager)
+        {
+            _tagHelperComponentManager = tagHelperComponentManager;
+        }
+
+        public IActionResult AddComponent()
+        {
+            _tagHelperComponentManager.Components.Add(new TestBodyTagHelperComponent(0, "Processed TagHelperComponent added from controller."));
+            return View("AddComponent");
+        }
+    }
+}

test/WebSites/RazorWebSite/Services/TestBodyTagHelperComponent.cs

@@ -7,15 +7,33 @@ using Microsoft.AspNetCore.Razor.TagHelpers;
 
 namespace RazorWebSite
 {
-    public class TestBodyTagHelperComponent : TagHelperComponent
+    public class TestBodyTagHelperComponent : ITagHelperComponent
     {
-        public override int Order => 1;
+        private int _order;
+        private string _html;
 
-        public override Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
+        public TestBodyTagHelperComponent() : this(1, "<script>'This was injected!!'</script>")
+        {
+
+        }
+
+        public TestBodyTagHelperComponent(int order, string html)
+        {
+            _order = order;
+            _html = html;
+        }
+
+        public int Order => _order;
+
+        public void Init(TagHelperContext context)
+        {
+        }
+
+        public Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
         {
             if (string.Equals(context.TagName, "body", StringComparison.Ordinal) && output.Attributes.ContainsName("inject"))
             {
-                output.PostContent.AppendHtml("<script>'This was injected!!'</script>");
+                output.PostContent.AppendHtml(_html);
             }
 
             return Task.FromResult(0);

test/WebSites/RazorWebSite/Views/AddTagHelperComponent/AddComponent.cshtml

@@ -0,0 +1,10 @@
+@inject Microsoft.AspNetCore.Mvc.Razor.TagHelpers.ITagHelperComponentManager manager
+<head inject>
+Hello from Head Tag Helper Component
+</head>
+@{ 
+    manager.Components.Add(new TestBodyTagHelperComponent(2, "Processed TagHelperComponent added from view."));
+}
+<body inject>
+Hello from Body Tag Helper Component
+</body>