Trim down framework references for Blazor dev server (#31420)

* Only include Microsoft.AspNetCore.App framework reference for Blazor dev server
* Address feedback from peer review
* Use SharedFxVersion property

eng/Versions.props

@@ -261,6 +261,7 @@
     <XunitExtensibilityExecutionVersion>$(XunitVersion)</XunitExtensibilityExecutionVersion>
     <XUnitRunnerVisualStudioVersion>2.4.3</XUnitRunnerVisualStudioVersion>
     <MicrosoftDataSqlClientVersion>1.0.19249.1</MicrosoftDataSqlClientVersion>
+    <MicrosoftAspNetCoreAppVersion>6.0.0-preview.3.21167.1</MicrosoftAspNetCoreAppVersion>
   </PropertyGroup>
   <!-- Restore feeds -->
   <PropertyGroup Label="Restore feeds">

src/Components/WebAssembly/DevServer/src/Microsoft.AspNetCore.Components.WebAssembly.DevServer.csproj

@@ -11,6 +11,9 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <!-- Set this to false because assemblies should not reference this assembly directly, (except for tests, of course). -->
     <IsProjectReferenceProvider>false</IsProjectReferenceProvider>
+    <!-- Disable the default runtimeconfig.json in favor of the one that we create which contains the correct
+    framework references. Workaround for issues launching Blazor WASM apps with IIS Express. -->
+    <GenerateRuntimeConfigurationFiles>false</GenerateRuntimeConfigurationFiles>
   </PropertyGroup>
 
   <ItemGroup>
@@ -19,6 +22,21 @@
     <Compile Include="$(SharedSourceRoot)CommandLineUtils\**\*.cs" />
   </ItemGroup>
 
+  <Target Name="_CreateRuntimeConfig" BeforeTargets="CoreBuild">
+    <PropertyGroup>
+      <_RuntimeConfigProperties>
+        SharedFxVersion=$(SharedFxVersion);
+      </_RuntimeConfigProperties>
+
+      <_RuntimeConfigPath>$(IntermediateOutputPath)blazor-devserver.runtimeconfig.json</_RuntimeConfigPath>
+    </PropertyGroup>
+
+    <GenerateFileFromTemplate
+      TemplateFile="blazor-devserver.runtimeconfig.json.in"
+      Properties="$(_RuntimeConfigProperties)"
+      OutputPath="$(_RuntimeConfigPath)" />
+  </Target>
+
   <!-- Pack settings -->
   <PropertyGroup>
     <GenerateNuspecDependsOn>$(GenerateNuspecDependsOn);publish</GenerateNuspecDependsOn>
@@ -28,6 +46,7 @@
 
   <ItemGroup>
     <NuspecProperty Include="publishDir=$(PublishDir)" />
+    <NuspecProperty Include="objDir=$(IntermediateOutputPath)" />
     <NuspecProperty Include="PackageThirdPartyNoticesFile=$(PackageThirdPartyNoticesFile)" />
   </ItemGroup>
 

src/Components/WebAssembly/DevServer/src/Microsoft.AspNetCore.Components.WebAssembly.DevServer.nuspec

@@ -8,5 +8,6 @@
     <file src="build\**" target="build" />
     <file src="$publishDir$**\*" target="tools" />
     <file src="$PackageThirdPartyNoticesFile$" target=".\THIRD-PARTY-NOTICES.txt" />
+    <file src="$objDir$blazor-devserver.runtimeconfig.json" target="tools\blazor-devserver.runtimeconfig.json" />
   </files>
 </package>

src/Components/WebAssembly/DevServer/src/blazor-devserver.runtimeconfig.json.in

@@ -0,0 +1,10 @@
+{
+  "runtimeOptions": {
+    "tfm": "net6.0",
+    "framework": {
+      "name": "Microsoft.AspNetCore.App",
+      "version": "${SharedFxVersion}"
+    },
+    "rollForwardOnNoCandidateFx": 2
+  }
+}