[Blazor] Consume fingerprinted assets in MVC and Blazor (#56045)

* Adds support for using fingerprinted assets in Blazor and MVC.
* Fingerprinted assets are registered as additional endpoints to the system.
* Static Assets exposes the descriptors so that they can be consumed and used by Blazor and MVC/Razor pages.
* Helper methods `WithStaticAssets` map specific MapControllers/RazorPages/RazorComponents invocations to a given `MapStaticAsset` invocation and expose a `ResourceAssetCollection` as endpoint metadata that can be later on used by the system to change the way markup is rendered.
* There's built-in support in all MVC Tag helpers (URLTagHelper, ImageTagHelper, LinkTagHelper, ScriptTagHelper).
* There's support for JavaScript import maps in the ScriptTagHelper to render a JavaScript import map that maps JS modules to their fingerprinted URLs.
* `ComponentBase` exposes an `Assets` property that lets Blazor components consume the fingerprinted names of a given asset.
* When webassembly is in use, an additional couple of endpoints is registered exposing the mapping to webassembly as an additional JS Module that webassembly apps can use to consume the mapping from client code.
* Caching is disabled during development for all assets to avoid issues and can be re-enabled through a configuration property.
* Similarly, integrity is not exposed during development to avoid issues where users change a file on the fly while the app is running.

Author: javiercn

AspNetCore.sln

@@ -1816,6 +1816,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GetDocumentInsider.Tests",
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "GetDocumentSample", "src\Tools\GetDocumentInsider\sample\GetDocumentSample.csproj", "{D8F7091E-A2D1-4E81-BA7C-97EAE392D683}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "BlazorUnitedApp.Client", "src\Components\Samples\BlazorUnitedApp.Client\BlazorUnitedApp.Client.csproj", "{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -10977,6 +10979,22 @@ Global
 		{D8F7091E-A2D1-4E81-BA7C-97EAE392D683}.Release|x64.Build.0 = Release|Any CPU
 		{D8F7091E-A2D1-4E81-BA7C-97EAE392D683}.Release|x86.ActiveCfg = Release|Any CPU
 		{D8F7091E-A2D1-4E81-BA7C-97EAE392D683}.Release|x86.Build.0 = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|arm64.ActiveCfg = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|arm64.Build.0 = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|x64.Build.0 = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Debug|x86.Build.0 = Debug|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|Any CPU.Build.0 = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|arm64.ActiveCfg = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|arm64.Build.0 = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|x64.ActiveCfg = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|x64.Build.0 = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|x86.ActiveCfg = Release|Any CPU
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -11874,6 +11892,7 @@ Global
 		{9536C284-65B4-4884-BB50-06D629095C3E} = {274100A5-5B2D-4EA2-AC42-A62257FC6BDC}
 		{6A19D94D-2BC6-4198-BE2E-342688FDBA4B} = {A1B75FC7-A777-4412-A635-D0C9ED8FE7A0}
 		{D8F7091E-A2D1-4E81-BA7C-97EAE392D683} = {A1B75FC7-A777-4412-A635-D0C9ED8FE7A0}
+		{757CBDE0-5D0A-4FD8-99F3-6C20BDDD4E63} = {5FE1FBC1-8CE3-4355-9866-44FE1307C5F1}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3E8720B3-DBDD-498C-B383-2CC32A054E8F}

src/Components/Components.slnf

@@ -19,6 +19,7 @@
       "src\\Components\\QuickGrid\\Microsoft.AspNetCore.Components.QuickGrid.EntityFrameworkAdapter\\src\\Microsoft.AspNetCore.Components.QuickGrid.EntityFrameworkAdapter.csproj",
       "src\\Components\\QuickGrid\\Microsoft.AspNetCore.Components.QuickGrid\\src\\Microsoft.AspNetCore.Components.QuickGrid.csproj",
       "src\\Components\\Samples\\BlazorServerApp\\BlazorServerApp.csproj",
+      "src\\Components\\Samples\\BlazorUnitedApp.Client\\BlazorUnitedApp.Client.csproj",
       "src\\Components\\Samples\\BlazorUnitedApp\\BlazorUnitedApp.csproj",
       "src\\Components\\Server\\src\\Microsoft.AspNetCore.Components.Server.csproj",
       "src\\Components\\Server\\test\\Microsoft.AspNetCore.Components.Server.Tests.csproj",

src/Components/Components/src/ComponentBase.cs

@@ -47,6 +47,11 @@ public ComponentBase()
     /// </summary>
     protected ComponentPlatform Platform => _renderHandle.Platform;
 
+    /// <summary>
+    /// Gets the <see cref="ResourceAssetCollection"/> for the application.
+    /// </summary>
+    protected ResourceAssetCollection Assets => _renderHandle.Assets;
+
     /// <summary>
     /// Gets the <see cref="IComponentRenderMode"/> assigned to this component.
     /// </summary>

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -1,4 +1,5 @@
 #nullable enable
+Microsoft.AspNetCore.Components.ComponentBase.Assets.get -> Microsoft.AspNetCore.Components.ResourceAssetCollection!
 Microsoft.AspNetCore.Components.ComponentBase.AssignedRenderMode.get -> Microsoft.AspNetCore.Components.IComponentRenderMode?
 Microsoft.AspNetCore.Components.ComponentBase.Platform.get -> Microsoft.AspNetCore.Components.ComponentPlatform!
 Microsoft.AspNetCore.Components.ComponentPlatform
@@ -7,6 +8,21 @@ Microsoft.AspNetCore.Components.ComponentPlatform.IsInteractive.get -> bool
 Microsoft.AspNetCore.Components.ComponentPlatform.Name.get -> string!
 Microsoft.AspNetCore.Components.ExcludeFromInteractiveRoutingAttribute
 Microsoft.AspNetCore.Components.ExcludeFromInteractiveRoutingAttribute.ExcludeFromInteractiveRoutingAttribute() -> void
+Microsoft.AspNetCore.Components.RenderHandle.Assets.get -> Microsoft.AspNetCore.Components.ResourceAssetCollection!
 Microsoft.AspNetCore.Components.RenderHandle.Platform.get -> Microsoft.AspNetCore.Components.ComponentPlatform!
 Microsoft.AspNetCore.Components.RenderHandle.RenderMode.get -> Microsoft.AspNetCore.Components.IComponentRenderMode?
+Microsoft.AspNetCore.Components.ResourceAsset
+Microsoft.AspNetCore.Components.ResourceAsset.Properties.get -> System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Components.ResourceAssetProperty!>?
+Microsoft.AspNetCore.Components.ResourceAsset.ResourceAsset(string! url, System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Components.ResourceAssetProperty!>? properties) -> void
+Microsoft.AspNetCore.Components.ResourceAsset.Url.get -> string!
+Microsoft.AspNetCore.Components.ResourceAssetCollection
+Microsoft.AspNetCore.Components.ResourceAssetCollection.IsContentSpecificUrl(string! path) -> bool
+Microsoft.AspNetCore.Components.ResourceAssetCollection.ResourceAssetCollection(System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Components.ResourceAsset!>! resources) -> void
+Microsoft.AspNetCore.Components.ResourceAssetCollection.this[string! key].get -> string!
+Microsoft.AspNetCore.Components.ResourceAssetProperty
+Microsoft.AspNetCore.Components.ResourceAssetProperty.Name.get -> string!
+Microsoft.AspNetCore.Components.ResourceAssetProperty.ResourceAssetProperty(string! name, string! value) -> void
+Microsoft.AspNetCore.Components.ResourceAssetProperty.Value.get -> string!
+static readonly Microsoft.AspNetCore.Components.ResourceAssetCollection.Empty -> Microsoft.AspNetCore.Components.ResourceAssetCollection!
+virtual Microsoft.AspNetCore.Components.RenderTree.Renderer.Assets.get -> Microsoft.AspNetCore.Components.ResourceAssetCollection!
 virtual Microsoft.AspNetCore.Components.RenderTree.Renderer.ComponentPlatform.get -> Microsoft.AspNetCore.Components.ComponentPlatform!

src/Components/Components/src/RenderHandle.cs

@@ -73,6 +73,17 @@ public IComponentRenderMode? RenderMode
         }
     }
 
+    /// <summary>
+    /// Gets the <see cref="ResourceAssetCollection"/> associated with the <see cref="Renderer"/>.
+    /// </summary>
+    public ResourceAssetCollection Assets
+    {
+        get
+        {
+            return _renderer?.Assets ?? throw new InvalidOperationException("No renderer has been initialized.");
+        }
+    }
+
     /// <summary>
     /// Notifies the renderer that the component should be rendered.
     /// </summary>

src/Components/Components/src/RenderTree/Renderer.cs

@@ -158,6 +158,11 @@ protected internal ComponentState GetComponentState(IComponent component)
     /// </summary>
     protected internal virtual ComponentPlatform ComponentPlatform { get; }
 
+    /// <summary>
+    /// Gets the <see cref="ResourceAssetCollection"/> associated with this <see cref="Renderer"/>.
+    /// </summary>
+    protected internal virtual ResourceAssetCollection Assets { get; } = ResourceAssetCollection.Empty;
+
     private async void RenderRootComponentsOnHotReload()
     {
         // Before re-rendering the root component, also clear any well-known caches in the framework

src/Components/Components/src/ResourceAsset.cs

@@ -0,0 +1,29 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics;
+using System.Linq;
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// A resource of the components application, such as a script, stylesheet or image.
+/// </summary>
+/// <param name="url">The URL of the resource.</param>
+/// <param name="properties">The properties associated to this resource.</param>
+[DebuggerDisplay($"{{{nameof(GetDebuggerDisplay)}(),nq}}")]
+public sealed class ResourceAsset(string url, IReadOnlyList<ResourceAssetProperty>? properties)
+{
+    /// <summary>
+    /// Gets the URL that identifies this resource.
+    /// </summary>
+    public string Url { get; } = url;
+
+    /// <summary>
+    /// Gets a list of properties associated to this resource.
+    /// </summary>
+    public IReadOnlyList<ResourceAssetProperty>? Properties { get; } = properties;
+
+    private string GetDebuggerDisplay() =>
+        $"Url: '{Url}' - Properties: {string.Join(", ", Properties?.Select(p => $"{p.Name} = {p.Value}") ?? [])}";
+}

src/Components/Components/src/ResourceAssetCollection.cs

@@ -0,0 +1,71 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections;
+using System.Collections.Frozen;
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// Describes a mapping of static assets to their corresponding unique URLs.
+/// </summary>
+public sealed class ResourceAssetCollection : IReadOnlyList<ResourceAsset>
+{
+    /// <summary>
+    /// An empty <see cref="ResourceAssetCollection"/>.
+    /// </summary>
+    public static readonly ResourceAssetCollection Empty = new([]);
+
+    private readonly FrozenDictionary<string, ResourceAsset> _uniqueUrlMappings;
+    private readonly FrozenSet<string> _contentSpecificUrls;
+    private readonly IReadOnlyList<ResourceAsset> _resources;
+
+    /// <summary>
+    /// Initializes a new instance of <see cref="ResourceAssetCollection"/>
+    /// </summary>
+    /// <param name="resources">The list of resources available.</param>
+    public ResourceAssetCollection(IReadOnlyList<ResourceAsset> resources)
+    {
+        var mappings = new Dictionary<string, ResourceAsset>(StringComparer.OrdinalIgnoreCase);
+        var contentSpecificUrls = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        _resources = resources;
+        foreach (var resource in resources)
+        {
+            foreach (var property in resource.Properties ?? [])
+            {
+                if (property.Name.Equals("label", StringComparison.OrdinalIgnoreCase))
+                {
+                    if (mappings.TryGetValue(property.Value, out var value))
+                    {
+                        throw new InvalidOperationException($"The static asset '{property.Value}' is already mapped to {value.Url}.");
+                    }
+                    mappings[property.Value] = resource;
+                    contentSpecificUrls.Add(resource.Url);
+                }
+            }
+        }
+
+        _uniqueUrlMappings = mappings.ToFrozenDictionary();
+        _contentSpecificUrls = contentSpecificUrls.ToFrozenSet();
+    }
+
+    /// <summary>
+    /// Gets the unique content-based URL for the specified static asset.
+    /// </summary>
+    /// <param name="key">The asset name.</param>
+    /// <returns>The unique URL if availabe, the same <paramref name="key"/> if not available.</returns>
+    public string this[string key] => _uniqueUrlMappings.TryGetValue(key, out var value) ? value.Url : key;
+
+    /// <summary>
+    /// Determines whether the specified path is a content-specific URL.
+    /// </summary>
+    /// <param name="path">The path to check.</param>
+    /// <returns><c>true</c> if the path is a content-specific URL; otherwise, <c>false</c>.</returns>
+    public bool IsContentSpecificUrl(string path) => _contentSpecificUrls.Contains(path);
+
+    // IReadOnlyList<ResourceAsset> implementation
+    ResourceAsset IReadOnlyList<ResourceAsset>.this[int index] => _resources[index];
+    int IReadOnlyCollection<ResourceAsset>.Count => _resources.Count;
+    IEnumerator<ResourceAsset> IEnumerable<ResourceAsset>.GetEnumerator() => _resources.GetEnumerator();
+    IEnumerator IEnumerable.GetEnumerator() => _resources.GetEnumerator();
+}

src/Components/Components/src/ResourceAssetProperty.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// A resource property.
+/// </summary>
+/// <param name="name">The name of the property.</param>
+/// <param name="value">The value of the property.</param>
+public sealed class ResourceAssetProperty(string name, string value)
+{
+    /// <summary>
+    /// Gets the name of the property.
+    /// </summary>
+    public string Name { get; } = name;
+
+    /// <summary>
+    /// Gets the value of the property.
+    /// </summary>
+    public string Value { get; } = value;
+}

src/Components/Components/test/ResourceAssetCollectionTest.cs

@@ -0,0 +1,88 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components;
+
+public class ResourceAssetCollectionTest
+{
+    [Fact]
+    public void CanCreateResourceCollection()
+    {
+        // Arrange
+        var resourceAssetCollection = new ResourceAssetCollection([
+            new ResourceAsset("image1.jpg",[]),
+            ]);
+
+        // Act
+        var collectionAsReadOnlyList = resourceAssetCollection as IReadOnlyList<ResourceAsset>;
+
+        // Assert
+        Assert.Equal(1, collectionAsReadOnlyList.Count);
+        Assert.Equal("image1.jpg", collectionAsReadOnlyList[0].Url);
+    }
+
+    [Fact]
+    public void CanResolveFingerprintedResources()
+    {
+        // Arrange
+        var resourceAssetCollection = new ResourceAssetCollection([
+            new ResourceAsset(
+                "image1.fingerprint.jpg",
+                [new ResourceAssetProperty("label", "image1.jpg")]),
+            ]);
+
+        // Act
+        var resolvedUrl = resourceAssetCollection["image1.jpg"];
+
+        // Assert
+        Assert.Equal("image1.fingerprint.jpg", resolvedUrl);
+    }
+
+    [Fact]
+    public void ResolvingNoFingerprintedResourcesReturnsSameUrl()
+    {
+        // Arrange
+        var resourceAssetCollection = new ResourceAssetCollection([
+            new ResourceAsset("image1.jpg",[])]);
+
+        // Act
+        var resolvedUrl = resourceAssetCollection["image1.jpg"];
+
+        // Assert
+        Assert.Equal("image1.jpg", resolvedUrl);
+    }
+
+    [Fact]
+    public void ResolvingNonExistentResourceReturnsSameUrl()
+    {
+        // Arrange
+        var resourceAssetCollection = new ResourceAssetCollection([
+            new ResourceAsset("image1.jpg",[])]);
+
+        // Act
+        var resolvedUrl = resourceAssetCollection["image2.jpg"];
+
+        // Assert
+        Assert.Equal("image2.jpg", resolvedUrl);
+    }
+
+    [Fact]
+    public void CanDetermineContentSpecificUrls()
+    {
+        // Arrange
+        var resourceAssetCollection = new ResourceAssetCollection([
+            new ResourceAsset("image1.jpg",[]),
+            new ResourceAsset(
+                "image2.fingerprint.jpg",
+                [new ResourceAssetProperty("label", "image2.jpg")]),
+            ]);
+
+        // Act
+        var isContentSpecificUrl1 = resourceAssetCollection.IsContentSpecificUrl("image1.jpg");
+        var isContentSpecificUrl2 = resourceAssetCollection.IsContentSpecificUrl("image2.fingerprint.jpg");
+
+        // Assert
+        Assert.False(isContentSpecificUrl1);
+        Assert.True(isContentSpecificUrl2);
+    }
+}

src/Components/Endpoints/src/Assets/ImportMap.cs

@@ -0,0 +1,63 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// Represents an <c><script type="importmap"></script></c> element that defines the import map for module scripts
+/// in the application.
+/// </summary>
+public sealed class ImportMap : IComponent
+{
+    private RenderHandle _renderHandle;
+    private bool _firstRender = true;
+    private ImportMapDefinition? _computedImportMapDefinition;
+
+    /// <summary>
+    /// Gets or sets the <see cref="HttpContext"/> for the component.
+    /// </summary>
+    [CascadingParameter] public HttpContext? HttpContext { get; set; } = null;
+
+    /// <summary>
+    /// Gets or sets the import map definition to use for the component. If not set
+    /// the component will generate the import map based on the assets defined for this
+    /// application.
+    /// </summary>
+    [Parameter]
+    public ImportMapDefinition? ImportMapDefinition { get; set; }
+
+    void IComponent.Attach(RenderHandle renderHandle)
+    {
+        _renderHandle = renderHandle;
+    }
+
+    Task IComponent.SetParametersAsync(ParameterView parameters)
+    {
+        parameters.SetParameterProperties(this);
+        if (!_firstRender && ReferenceEquals(ImportMapDefinition, _computedImportMapDefinition))
+        {
+            return Task.CompletedTask;
+        }
+        else
+        {
+            _firstRender = false;
+            _computedImportMapDefinition = ImportMapDefinition ?? HttpContext?.GetEndpoint()?.Metadata.GetMetadata<ImportMapDefinition>();
+            if (_computedImportMapDefinition != null)
+            {
+                _renderHandle.Render(RenderImportMap);
+            }
+            return Task.CompletedTask;
+        }
+    }
+
+    private void RenderImportMap(RenderTreeBuilder builder)
+    {
+        builder.OpenElement(0, "script");
+        builder.AddAttribute(1, "type", "importmap");
+        builder.AddMarkupContent(2, _computedImportMapDefinition!.ToJson());
+        builder.CloseElement();
+    }
+}