Write import map to html files

src/BlazorWasmSdk/Targets/Microsoft.NET.Sdk.BlazorWebAssembly.6_0.targets

@@ -50,9 +50,15 @@ Copyright (c) .NET Foundation. All rights reserved.
     <DebuggerSupport Condition="'$(DebuggerSupport)' == '' and '$(Configuration)' != 'Debug'">false</DebuggerSupport>
     <BlazorCacheBootResources Condition="'$(BlazorCacheBootResources)' == ''">true</BlazorCacheBootResources>
 
+    <_TargetingNETBefore80>$([MSBuild]::VersionLessThan('$(TargetFrameworkVersion)', '8.0'))</_TargetingNETBefore80>
     <_TargetingNET80OrLater>$([MSBuild]::VersionGreaterThanOrEquals('$(TargetFrameworkVersion)', '8.0'))</_TargetingNET80OrLater>
-    <WasmFingerprintDotnetJs>true</WasmFingerprintDotnetJs>
-    <WasmFingerprintDotnetJs Condition="'$(_TargetingNET80OrLater)' == 'true'">false</WasmFingerprintDotnetJs>
+    <_TargetingNETBefore100>$([MSBuild]::VersionLessThan('$(TargetFrameworkVersion)', '10.0'))</_TargetingNETBefore100>
+
+    <!--  8 <  .NET      we want to fingerprint dotnet.js because it's part of the blazor.boot.json which is loaded from blazor.webassembly.js -->
+    <!--  8 <= .NET < 10 we don't want to fingerprint dotnet.js because it's path is hardcoded in blazor.webassembly.js -->
+    <!-- 10 <= .NET      we want to leave fingerprinting to WasmSDK because it knows if import maps where applied -->
+    <WasmFingerprintDotnetJs Condition="'$(_TargetingNETBefore80)' == 'true'">true</WasmFingerprintDotnetJs>
+    <WasmFingerprintDotnetJs Condition="'$(_TargetingNET80OrLater)' == 'true' and '$(_TargetingNETBefore100)' == 'true'">false</WasmFingerprintDotnetJs>
     <WasmEnableWebcil Condition="'$(WasmEnableWebcil)' == '' and ('$(TargetFrameworkIdentifier)' != '.NETCoreApp' or '$(_TargetingNET80OrLater)' != 'true')">false</WasmEnableWebcil>
 
     <!-- Turn off parts of the build that do not apply to Blazor projects -->

src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets

@@ -0,0 +1,212 @@
+<!--
+***********************************************************************************************
+Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
+
+WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and have
+          created a backup copy.  Incorrect changes to this file will make it
+          impossible to load or build your projects from the command-line or the IDE.
+
+Copyright (c) .NET Foundation. All rights reserved.
+***********************************************************************************************
+-->
+
+<Project ToolsVersion="14.0">
+
+  <UsingTask TaskName="Microsoft.AspNetCore.StaticWebAssets.Tasks.WriteImportMapToHtml" AssemblyFile="$(StaticWebAssetsSdkBuildTasksAssembly)" />
+
+  <PropertyGroup>
+
+    <!--
+        ResolveBuildRelatedStaticWebAssets
+          ResolveHtmlImportMapBuildStaticWebAssets
+            GenerateHtmlImportMapBuildStaticWebAssets
+              ResolveHtmlImportMapBuildConfiguration
+     -->
+    <ResolveBuildRelatedStaticWebAssetsDependsOn>
+      $(ResolveBuildRelatedStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapBuildStaticWebAssets;
+    </ResolveBuildRelatedStaticWebAssetsDependsOn>
+    <ResolveCompressedFilesDependsOn>
+      $(ResolveCompressedFilesDependsOn);
+      ResolveHtmlImportMapBuildStaticWebAssets
+    </ResolveCompressedFilesDependsOn>
+    <ResolveBuildServiceWorkerStaticWebAssetsDependsOn>
+      $(ResolveBuildServiceWorkerStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapBuildStaticWebAssets
+    </ResolveBuildServiceWorkerStaticWebAssetsDependsOn>
+    <ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
+      GenerateHtmlImportMapBuildStaticWebAssets;
+      $(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn)
+    </ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
+    <GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+      ResolveHtmlImportMapBuildConfiguration;
+      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)
+    </GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+
+    <!--
+        ResolvePublishRelatedStaticWebAssets
+          ResolveHtmlImportMapPublishStaticWebAssets
+            GenerateHtmlImportMapPublishStaticWebAssets
+              ResolveHtmlImportMapPublishConfiguration
+     -->
+    <ResolvePublishRelatedStaticWebAssetsDependsOn>
+      $(ResolvePublishRelatedStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapPublishStaticWebAssets
+    </ResolvePublishRelatedStaticWebAssetsDependsOn>
+    <ResolvePublishCompressedStaticWebAssetsDependsOn>
+      $(ResolvePublishCompressedStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapPublishStaticWebAssets
+    </ResolvePublishCompressedStaticWebAssetsDependsOn>
+    <ResolvePublishServiceWorkerStaticWebAssetsDependsOn>
+      $(ResolvePublishServiceWorkerStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapPublishStaticWebAssets
+    </ResolvePublishServiceWorkerStaticWebAssetsDependsOn>
+    <ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
+      GenerateHtmlImportMapPublishStaticWebAssets;
+      $(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn)
+    </ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
+    <GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
+      ResolveHtmlImportMapPublishConfiguration;
+      $(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn)
+    </GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
+
+  </PropertyGroup>
+
+  <!-- Build -->
+
+  <Target Name="ResolveHtmlImportMapBuildConfiguration">
+    <PropertyGroup>
+      <_BuildImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'build'))</_BuildImportMapHtmlPath>
+    </PropertyGroup>
+
+    <MakeDir Directories="$(_BuildImportMapHtmlPath)"/>
+
+    <ItemGroup>
+      <_HtmlStaticWebAssets Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Publish' and '%(Extension)' == '.html'" />
+      <_EsModuleCandidate Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Publish'" />
+    </ItemGroup>
+
+    <FilterStaticWebAssetEndpoints Condition="'@(_EsModuleCandidate)' != ''"
+      Endpoints="@(StaticWebAssetEndpoint)"
+      Assets="@(_EsModuleCandidate)"
+      Filters=""
+    >
+      <Output TaskParameter="FilteredEndpoints" ItemName="_EsModuleCandidateEndpoints" />
+    </FilterStaticWebAssetEndpoints>
+  </Target>
+
+  <Target Name="GenerateHtmlImportMapBuildStaticWebAssets" DependsOnTargets="$(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)">
+    <WriteImportMapToHtml
+      Endpoints="@(_EsModuleCandidateEndpoints)"
+      HtmlFiles="@(_HtmlStaticWebAssets)"
+      OutputPath="$(_BuildImportMapHtmlPath)">
+      <Output TaskParameter="HtmlCandidates" ItemName="_HtmlCandidates" />
+      <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlFilesToRemove" />
+      <Output TaskParameter="FileWrites" ItemName="FileWrites" />
+    </WriteImportMapToHtml>
+  </Target>
+
+  <Target Name="ResolveHtmlImportMapBuildStaticWebAssets" DependsOnTargets="$(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn)">
+    <ItemGroup>
+      <_HtmlCandidatesNoMetadata
+        Include="@(_HtmlCandidates)"
+        RemoveMetadata="SourceType;AssetKind;Integrity;Fingerprint" />
+      <_HtmlCandidatesNoMetadata ContentRoot="$(_BuildImportMapHtmlPath)" />
+    </ItemGroup>
+    <DefineStaticWebAssets CandidateAssets="@(_HtmlCandidatesNoMetadata)"
+      SourceType="Computed"
+      AssetKind="Build"
+    >
+      <Output TaskParameter="Assets" ItemName="_UpdatedHtmlStaticWebAssets" />
+    </DefineStaticWebAssets>
+    <DefineStaticWebAssetEndpoints
+      CandidateAssets="@(_UpdatedHtmlStaticWebAssets)"
+      ExistingEndpoints="@(StaticWebAssetEndpoint)"
+      ContentTypeMappings="@(StaticWebAssetContentTypeMapping)"
+    >
+      <Output TaskParameter="Endpoints" ItemName="_UpdatedHtmlStaticWebAssetsEndpoint" />
+    </DefineStaticWebAssetEndpoints>
+    <FilterStaticWebAssetEndpoints Condition="'@(_HtmlFilesToRemove)' != ''"
+      Endpoints="@(StaticWebAssetEndpoint)"
+      Assets="@(_HtmlFilesToRemove)"
+      Filters=""
+    >
+      <Output TaskParameter="FilteredEndpoints" ItemName="_HtmlFileEndpointsToRemove" />
+    </FilterStaticWebAssetEndpoints>
+    <ItemGroup>
+      <StaticWebAsset Remove="@(_HtmlFilesToRemove)" />
+      <StaticWebAsset Include="@(_UpdatedHtmlStaticWebAssets)" />
+      <StaticWebAssetEndpoint Remove="@(_HtmlFileEndpointsToRemove)" />
+      <StaticWebAssetEndpoint Include="@(_UpdatedHtmlStaticWebAssetsEndpoint)" />
+    </ItemGroup>
+  </Target>
+
+  <!-- Publish -->
+
+  <Target Name="ResolveHtmlImportMapPublishConfiguration">
+    <PropertyGroup>
+      <_PublishImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'publish'))</_PublishImportMapHtmlPath>
+    </PropertyGroup>
+
+    <MakeDir Directories="$(_PublishImportMapHtmlPath)"/>
+
+    <ItemGroup>
+      <_EsModuleCandidateForPublish Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Build'" />
+    </ItemGroup>
+
+    <FilterStaticWebAssetEndpoints Condition="'@(_EsModuleCandidateForPublish)' != ''"
+      Endpoints="@(StaticWebAssetEndpoint)"
+      Assets="@(_EsModuleCandidateForPublish)"
+      Filters=""
+    >
+      <Output TaskParameter="FilteredEndpoints" ItemName="_EsModuleCandidateForPublishEndpoints" />
+    </FilterStaticWebAssetEndpoints>
+  </Target>
+
+  <Target Name="GenerateHtmlImportMapPublishStaticWebAssets" DependsOnTargets="$(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn)">
+    <WriteImportMapToHtml
+      Endpoints="@(_EsModuleCandidateForPublishEndpoints)"
+      HtmlFiles="@(_HtmlStaticWebAssets)"
+      OutputPath="$(_PublishImportMapHtmlPath)">
+      <Output TaskParameter="HtmlCandidates" ItemName="_HtmlPublishCandidates" />
+      <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlPublishFilesToRemove" />
+      <Output TaskParameter="FileWrites" ItemName="FileWrites" />
+    </WriteImportMapToHtml>
+  </Target>
+
+  <Target Name="ResolveHtmlImportMapPublishStaticWebAssets" DependsOnTargets="$(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn)">
+    <ItemGroup>
+      <_HtmlPublishCandidatesNoMetadata
+        Include="@(_HtmlPublishCandidates)"
+        RemoveMetadata="SourceType;AssetKind;Integrity;Fingerprint" />
+      <_HtmlPublishCandidatesNoMetadata ContentRoot="$(_PublishImportMapHtmlPath)" />
+    </ItemGroup>
+    <DefineStaticWebAssets CandidateAssets="@(_HtmlPublishCandidatesNoMetadata)"
+      SourceType="Computed"
+      AssetKind="Publish"
+    >
+      <Output TaskParameter="Assets" ItemName="_UpdatedHtmlPublishStaticWebAssets" />
+    </DefineStaticWebAssets>
+    <DefineStaticWebAssetEndpoints
+      CandidateAssets="@(_UpdatedHtmlPublishStaticWebAssets)"
+      ExistingEndpoints="@(StaticWebAssetEndpoint)"
+      ContentTypeMappings="@(StaticWebAssetContentTypeMapping)"
+    >
+      <Output TaskParameter="Endpoints" ItemName="_UpdatedHtmlPublishStaticWebAssetsEndpoint" />
+    </DefineStaticWebAssetEndpoints>
+    <FilterStaticWebAssetEndpoints Condition="'@(_HtmlPublishFilesToRemove)' != ''"
+      Endpoints="@(StaticWebAssetEndpoint)"
+      Assets="@(_HtmlPublishFilesToRemove)"
+      Filters=""
+    >
+      <Output TaskParameter="FilteredEndpoints" ItemName="_HtmlPublishFileEndpointsToRemove" />
+    </FilterStaticWebAssetEndpoints>
+    <ItemGroup>
+      <StaticWebAsset Remove="@(_HtmlPublishFilesToRemove)" />
+      <StaticWebAsset Include="@(_UpdatedHtmlPublishStaticWebAssets)" />
+      <StaticWebAssetEndpoint Remove="@(_HtmlPublishFileEndpointsToRemove)" />
+      <StaticWebAssetEndpoint Include="@(_UpdatedHtmlPublishStaticWebAssetsEndpoint)" />
+    </ItemGroup>
+  </Target>
+
+</Project>

src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets

@@ -737,5 +737,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Import Project="Microsoft.NET.Sdk.StaticWebAssets.Compression.targets" Condition="'$(CompressionEnabled)' == 'true'" />
 
   <Import Project="Microsoft.NET.Sdk.StaticWebAssets.ServiceWorker.targets" Condition="'$(ServiceWorkerAssetsManifest)' != ''" />
+
+  <Import Project="Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets" Condition="'$(WriteImportMapToHtml)' == 'true'" />
 
 </Project>

src/StaticWebAssetsSdk/Tasks/Utils/ArtifactWriter.cs

@@ -10,9 +10,14 @@ namespace Microsoft.AspNetCore.StaticWebAssets.Tasks.Utils;
 
 public static class ArtifactWriter
 {
-    public static void PersistFileIfChanged<T>(this Task task, T manifest, string artifactPath, JsonTypeInfo<T> serializer)
+    public static bool PersistFileIfChanged<T>(this Task task, T manifest, string artifactPath, JsonTypeInfo<T> serializer)
     {
         var data = JsonSerializer.SerializeToUtf8Bytes(manifest, serializer);
+        return PersistFileIfChanged(task, data, artifactPath);
+    }
+
+    public static bool PersistFileIfChanged(this Task task, byte[] data, string artifactPath)
+    {
         var newHash = ComputeHash(data);
         var fileExists = File.Exists(artifactPath);
         var existingManifestHash = fileExists ? ComputeHash(artifactPath) : null;
@@ -21,15 +26,18 @@ public static void PersistFileIfChanged<T>(this Task task, T manifest, string ar
         {
             task.Log.LogMessage(MessageImportance.Low, $"Creating artifact because artifact file '{artifactPath}' does not exist.");
             File.WriteAllBytes(artifactPath, data);
+            return true;
         }
         else if (!string.Equals(newHash, existingManifestHash, StringComparison.Ordinal))
         {
             task.Log.LogMessage(MessageImportance.Low, $"Updating artifact because artifact version '{newHash}' is different from existing artifact hash '{existingManifestHash}'.");
             File.WriteAllBytes(artifactPath, data);
+            return true;
         }
         else
         {
             task.Log.LogMessage(MessageImportance.Low, $"Skipping artifact updated because artifact version '{existingManifestHash}' has not changed.");
+            return false;
         }
     }