Influence HTML head from Blazor

AspNetCore.sln

@@ -1427,6 +1427,20 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Compon
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.AspNetCore.Components.Web.Extensions.Tests", "src\Components\Web.Extensions\test\Microsoft.AspNetCore.Components.Web.Extensions.Tests.csproj", "{157605CB-5170-4C1A-980F-4BAE42DB60DE}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "testassets", "testassets", "{2531F00A-54EB-4074-9C0B-9AF9FB3679DC}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "BasicTestApp", "src\Components\test\testassets\BasicTestApp\BasicTestApp.csproj", "{85D67E40-4B11-48ED-8C43-34590A1FB9ED}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LazyTestContentPackage", "src\Components\test\testassets\LazyTestContentPackage\LazyTestContentPackage.csproj", "{C0EF53A5-5A94-4849-86B0-2297EA08D649}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ComponentsApp.App", "src\Components\test\testassets\ComponentsApp.App\ComponentsApp.App.csproj", "{4FDD820F-8397-41B7-956E-F257DD044BD8}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ComponentsApp.Server", "src\Components\test\testassets\ComponentsApp.Server\ComponentsApp.Server.csproj", "{CA7C7A53-446F-453A-A57B-78BB1443B8A8}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TestContentPackage", "src\Components\test\testassets\TestContentPackage\TestContentPackage.csproj", "{B32C5882-2313-40D0-A003-2FF33724CFE6}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Components.TestServer", "src\Components\test\testassets\TestServer\Components.TestServer.csproj", "{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}"
+EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Sdk", "Sdk", "{FED4267E-E5E4-49C5-98DB-8B3F203596EE}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.NET.Sdk.BlazorWebAssembly", "src\Components\WebAssembly\Sdk\src\Microsoft.NET.Sdk.BlazorWebAssembly.csproj", "{6B2734BF-C61D-4889-ABBF-456A4075D59B}"
@@ -6739,6 +6753,78 @@ Global
 		{157605CB-5170-4C1A-980F-4BAE42DB60DE}.Release|x64.Build.0 = Release|Any CPU
 		{157605CB-5170-4C1A-980F-4BAE42DB60DE}.Release|x86.ActiveCfg = Release|Any CPU
 		{157605CB-5170-4C1A-980F-4BAE42DB60DE}.Release|x86.Build.0 = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|x64.Build.0 = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Debug|x86.Build.0 = Debug|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|Any CPU.Build.0 = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|x64.ActiveCfg = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|x64.Build.0 = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|x86.ActiveCfg = Release|Any CPU
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED}.Release|x86.Build.0 = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|x64.Build.0 = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Debug|x86.Build.0 = Debug|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|x64.ActiveCfg = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|x64.Build.0 = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|x86.ActiveCfg = Release|Any CPU
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649}.Release|x86.Build.0 = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|x64.Build.0 = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Debug|x86.Build.0 = Debug|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|x64.ActiveCfg = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|x64.Build.0 = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|x86.ActiveCfg = Release|Any CPU
+		{4FDD820F-8397-41B7-956E-F257DD044BD8}.Release|x86.Build.0 = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|x64.Build.0 = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Debug|x86.Build.0 = Debug|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|x64.ActiveCfg = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|x64.Build.0 = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|x86.ActiveCfg = Release|Any CPU
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8}.Release|x86.Build.0 = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|x64.Build.0 = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Debug|x86.Build.0 = Debug|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|x64.ActiveCfg = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|x64.Build.0 = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|x86.ActiveCfg = Release|Any CPU
+		{B32C5882-2313-40D0-A003-2FF33724CFE6}.Release|x86.Build.0 = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|x64.Build.0 = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Debug|x86.Build.0 = Debug|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|Any CPU.Build.0 = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|x64.ActiveCfg = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|x64.Build.0 = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|x86.ActiveCfg = Release|Any CPU
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00}.Release|x86.Build.0 = Release|Any CPU
 		{6B2734BF-C61D-4889-ABBF-456A4075D59B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{6B2734BF-C61D-4889-ABBF-456A4075D59B}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{6B2734BF-C61D-4889-ABBF-456A4075D59B}.Debug|x64.ActiveCfg = Debug|Any CPU
@@ -7502,6 +7588,13 @@ Global
 		{F71FE795-9923-461B-9809-BB1821A276D0} = {60D51C98-2CC0-40DF-B338-44154EFEE2FF}
 		{8294A74F-7DAA-4B69-BC56-7634D93C9693} = {F71FE795-9923-461B-9809-BB1821A276D0}
 		{157605CB-5170-4C1A-980F-4BAE42DB60DE} = {F71FE795-9923-461B-9809-BB1821A276D0}
+		{2531F00A-54EB-4074-9C0B-9AF9FB3679DC} = {0508E463-0269-40C9-B5C2-3B600FB2A28B}
+		{85D67E40-4B11-48ED-8C43-34590A1FB9ED} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
+		{C0EF53A5-5A94-4849-86B0-2297EA08D649} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
+		{4FDD820F-8397-41B7-956E-F257DD044BD8} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
+		{CA7C7A53-446F-453A-A57B-78BB1443B8A8} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
+		{B32C5882-2313-40D0-A003-2FF33724CFE6} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
+		{26F88A06-319C-43F3-9FD9-8BC2D29F8C00} = {2531F00A-54EB-4074-9C0B-9AF9FB3679DC}
 		{FED4267E-E5E4-49C5-98DB-8B3F203596EE} = {562D5067-8CD8-4F19-BCBB-873204932C61}
 		{6B2734BF-C61D-4889-ABBF-456A4075D59B} = {FED4267E-E5E4-49C5-98DB-8B3F203596EE}
 		{83371889-9A3E-4D16-AE77-EB4F83BC6374} = {FED4267E-E5E4-49C5-98DB-8B3F203596EE}

src/Components/Web.Extensions/src/HeadManagement/HeadManagementJSRuntimeExtensions.cs

@@ -0,0 +1,28 @@
+// 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.Threading.Tasks;
+using Microsoft.JSInterop;
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    internal static class HeadManagementJSRuntimeExtensions
+    {
+        private const string JsFunctionsPrefix = "_blazorHeadManager";
+
+        public static ValueTask SetTitleAsync(this IJSRuntime jsRuntime, string title)
+        {
+            return jsRuntime.InvokeVoidAsync($"{JsFunctionsPrefix}.setTitle", title);
+        }
+
+        public static ValueTask AddOrUpdateHeadTagAsync(this IJSRuntime jsRuntime, TagElement tag, string id)
+        {
+            return jsRuntime.InvokeVoidAsync($"{JsFunctionsPrefix}.addOrUpdateHeadTag", tag, id);
+        }
+
+        public static ValueTask RemoveHeadTagAsync(this IJSRuntime jsRuntime, string id)
+        {
+            return jsRuntime.InvokeVoidAsync($"{JsFunctionsPrefix}.removeHeadTag", id);
+        }
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/HeadTagBase.cs

@@ -0,0 +1,67 @@
+// 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 System.Text.Json;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.JSInterop;
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    /// <summary>
+    /// Serves as a base for components that represent tags in the HTML head.
+    /// </summary>
+    public abstract class HeadTagBase : ComponentBase, IDisposable
+    {
+        private readonly string _id = Guid.NewGuid().ToString("N");
+
+        private TagElement _tagElement;
+
+        private bool _hasRendered;
+
+        [Inject]
+        private IJSRuntime JSRuntime { get; set; } = default!;
+
+        /// <summary>
+        /// Gets or sets a collection of additional attributes that will be applied to the meta element.
+        /// </summary>
+        [Parameter(CaptureUnmatchedValues = true)]
+        public IReadOnlyDictionary<string, object>? Attributes { get; set; }
+
+        /// <summary>
+        /// Gets the name of the tag being represented.
+        /// </summary>
+        protected abstract string TagName { get; }
+
+        /// <inheritdoc />
+        protected override void OnParametersSet()
+        {
+            _tagElement = new TagElement(TagName, Attributes);
+        }
+
+        /// <inheritdoc />
+        protected override async Task OnAfterRenderAsync(bool firstRender)
+        {
+            _hasRendered = true;
+
+            await JSRuntime.AddOrUpdateHeadTagAsync(_tagElement, _id);
+        }
+
+        /// <inheritdoc />
+        protected override void BuildRenderTree(RenderTreeBuilder builder)
+        {
+            builder.AddMarkupContent(0, $"<!--Head:{JsonSerializer.Serialize(_tagElement, JsonSerializerOptionsProvider.Options)}-->");
+        }
+
+        /// <inheritdoc />
+        public void Dispose()
+        {
+            if (_hasRendered)
+            {
+                _ = JSRuntime.RemoveHeadTagAsync(_id);
+            }
+        }
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/Link.cs

@@ -0,0 +1,14 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    /// <summary>
+    /// A component that adds a link tag to the HTML head.
+    /// </summary>
+    public sealed class Link : HeadTagBase
+    {
+        /// <inheritdoc />
+        protected override string TagName => "link";
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/Meta.cs

@@ -0,0 +1,14 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    /// <summary>
+    /// A component that adds a meta tag to the HTML head.
+    /// </summary>
+    public sealed class Meta : HeadTagBase
+    {
+        /// <inheritdoc />
+        protected override string TagName => "meta";
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/TagElement.cs

@@ -0,0 +1,22 @@
+// 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;
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    internal readonly struct TagElement
+    {
+        public string Type => "tag";
+
+        public string TagName { get; }
+
+        public IReadOnlyDictionary<string, object>? Attributes { get; }
+
+        public TagElement(string tagName, IReadOnlyDictionary<string, object>? attributes)
+        {
+            TagName = tagName;
+            Attributes = attributes;
+        }
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/Title.cs

@@ -0,0 +1,37 @@
+// 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.Text.Json;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.JSInterop;
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    /// <summary>
+    /// A component that changes the title of the document.
+    /// </summary>
+    public sealed class Title : ComponentBase
+    {
+        [Inject]
+        private IJSRuntime JSRuntime { get; set; } = default!;
+
+        /// <summary>
+        /// Gets or sets the value to use as the document's title.
+        /// </summary>
+        [Parameter]
+        public string Value { get; set; } = string.Empty;
+
+        /// <inheritdoc />
+        protected override async Task OnAfterRenderAsync(bool firstRender)
+        {
+            await JSRuntime.SetTitleAsync(Value);
+        }
+
+        /// <inheritdoc />
+        protected override void BuildRenderTree(RenderTreeBuilder builder)
+        {
+            builder.AddMarkupContent(0, $"<!--Head:{JsonSerializer.Serialize(new TitleElement(Value), JsonSerializerOptionsProvider.Options)}-->");
+        }
+    }
+}

src/Components/Web.Extensions/src/HeadManagement/TitleElement.cs

@@ -0,0 +1,17 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Components.Web.Extensions.Head
+{
+    internal readonly struct TitleElement
+    {
+        public string Type => "title";
+
+        public string Title { get; }
+
+        public TitleElement(string title)
+        {
+            Title = title;
+        }
+    }
+}

src/Components/Web.Extensions/src/Microsoft.AspNetCore.Components.Web.Extensions.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk.Razor">
 
   <PropertyGroup>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
@@ -9,6 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Reference Include="Microsoft.AspNetCore.Components" />
     <Reference Include="Microsoft.AspNetCore.DataProtection" />
     <Reference Include="Microsoft.JSInterop" />
   </ItemGroup>

src/Components/Web.Extensions/src/Properties/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.AspNetCore.Components.Web.Extensions.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]