Integrate with IIISEnvironmentFeature

This change adds support for IIISEnvironmentFeature, as well as a copy
of it internally so we can have similar behavior within the adapters
across all supported .NET versions and servers.

Author: twsouthwick

global.json

@@ -1,15 +1,17 @@
 {
   "sdk": {
-    "version": "8.0.100-rc.1.23455.8"
+    "version": "8.0.100-rc.2.23502.2"
   },
   "tools": {
-    "dotnet": "8.0.100-rc.1.23455.8",
+    "dotnet": "8.0.100-rc.2.23502.2",
     "runtimes": {
       "dotnet": [
-        "6.0.4"
+        "6.0.4",
+        "7.0.12"
       ],
       "aspnetcore": [
-        "6.0.4"
+        "6.0.4",
+        "7.0.12"
       ]
     }
   },

src/Microsoft.AspNetCore.SystemWebAdapters.CoreServices/Features/IIISEnvironmentFeature.cs

@@ -0,0 +1,60 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#if !NET8_0_OR_GREATER
+using System;
+
+namespace Microsoft.AspNetCore.Server.IIS;
+
+/// <summary>
+/// This feature provides access to IIS application information. This is <see href="https://github.com/dotnet/aspnetcore/blob/4218bd758012820a955b0185e5b1824168d00c6a/src/Servers/IIS/IIS/src/IIISEnvironmentFeature.cs">available in-box</see>
+/// on .NET 8, but we have an internal copy so we can utilize its features on downlevel versions.
+/// </summary>
+internal interface IIISEnvironmentFeature
+{
+    /// <summary>
+    /// Gets the version of IIS that is being used.
+    /// </summary>
+    Version IISVersion { get; }
+
+    /// <summary>
+    /// Gets the AppPool name that is currently running
+    /// </summary>
+    string AppPoolId { get; }
+
+    /// <summary>
+    /// Gets the path to the AppPool config
+    /// </summary>
+    string AppPoolConfigFile { get; }
+
+    /// <summary>
+    /// Gets path to the application configuration that is currently running
+    /// </summary>
+    string AppConfigPath { get; }
+
+    /// <summary>
+    /// Gets the physical path of the application.
+    /// </summary>
+    string ApplicationPhysicalPath { get; }
+
+    /// <summary>
+    /// Gets the virtual path of the application.
+    /// </summary>
+    string ApplicationVirtualPath { get; }
+
+    /// <summary>
+    /// Gets ID of the current application.
+    /// </summary>
+    string ApplicationId { get; }
+
+    /// <summary>
+    /// Gets the name of the current site.
+    /// </summary>
+    string SiteName { get; }
+
+    /// <summary>
+    /// Gets the id of the current site.
+    /// </summary>
+    uint SiteId { get; }
+}
+#endif

src/Microsoft.AspNetCore.SystemWebAdapters.CoreServices/HostingRuntimeExtensions.cs

@@ -8,6 +8,10 @@
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.AspNetCore.Server.IIS;
+using Microsoft.Extensions.Configuration;
+using Microsoft.AspNetCore.Hosting.Server;
 
 namespace Microsoft.AspNetCore.SystemWebAdapters;
 
@@ -21,6 +25,8 @@ public static void AddHostingRuntime(this IServiceCollection services)
         services.TryAddEnumerable(ServiceDescriptor.Singleton<IStartupFilter, HostingEnvironmentStartupFilter>());
 
         services.AddOptions<SystemWebAdaptersOptions>()
+
+            // This configures for anyone using older IIS modules that don't set the values (and to maintain behavior with the adapters <1.3)
             .Configure(options =>
             {
                 options.IsHosted = true;
@@ -32,6 +38,20 @@ public static void AddHostingRuntime(this IServiceCollection services)
                     options.AppDomainAppVirtualPath = config.pwzVirtualApplicationPath;
                     options.AppDomainAppPath = config.pwzFullApplicationPath;
                 }
+            })
+
+            // On .NET 8+, IIISEnvironmentFeature is available by default if running on IIS. We have an internal version
+            // we load at startup so that regardless of version and server this may be available (for example, in case some
+            // one wants to set the environment variables on a Kestrel hosted system to get the behavior)
+            .Configure<IServer>((options, server) =>
+            {
+                if (server.Features.Get<IIISEnvironmentFeature>() is { } feature)
+                {
+                    options.AppDomainAppPath = feature.ApplicationPhysicalPath;
+                    options.AppDomainAppVirtualPath = feature.ApplicationVirtualPath;
+                    options.ApplicationID = feature.ApplicationId;
+                    options.SiteName = feature.SiteName;
+                }
             });
     }
 
@@ -43,11 +63,82 @@ public HostingEnvironmentStartupFilter(HostingEnvironmentAccessor accessor)
         }
 
         public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
-            => builder => next(builder);
+            => builder =>
+            {
+                // We ensure this feature is available for both pre-.NET 8 as well as .NET 8+ on non-IIS systems if the right environment variables are set
+                if (builder.ApplicationServices.GetService<IServer>() is { } server && server.Features.Get<IIISEnvironmentFeature>() is null)
+                {
+                    if (IISEnvironmentFeature.TryCreate(builder.ApplicationServices.GetRequiredService<IConfiguration>(), out var feature))
+                    {
+                        server.Features.Set<IIISEnvironmentFeature>(feature);
+                    }
+                }
+
+                next(builder);
+            };
 
         public void Dispose()
         {
             HostingEnvironmentAccessor.Current = null;
         }
     }
+
+    /// <summary>
+    /// Copy of https://github.com/dotnet/aspnetcore/blob/4218bd758012820a955b0185e5b1824168d00c6a/src/Servers/IIS/IIS/src/Core/IISEnvironmentFeature.cs
+    /// </summary>
+    private sealed class IISEnvironmentFeature : IIISEnvironmentFeature
+    {
+        public static bool TryCreate(IConfiguration configuration, [NotNullWhen(true)] out IIISEnvironmentFeature? result)
+        {
+            var feature = new IISEnvironmentFeature(configuration);
+
+            if (feature.IISVersion is not null)
+            {
+                result = feature;
+                return true;
+            }
+
+            result = null;
+            return false;
+        }
+
+        private IISEnvironmentFeature(IConfiguration configuration)
+        {
+            if (Version.TryParse(configuration["IIS_VERSION"], out var version))
+            {
+                IISVersion = version;
+            }
+
+            if (uint.TryParse(configuration["IIS_SITE_ID"], out var siteId))
+            {
+                SiteId = siteId;
+            }
+
+            AppPoolId = configuration["IIS_APP_POOL_ID"] ?? string.Empty;
+            AppPoolConfigFile = configuration["IIS_APP_POOL_CONFIG_FILE"] ?? string.Empty;
+            AppConfigPath = configuration["IIS_APP_CONFIG_PATH"] ?? string.Empty;
+            ApplicationPhysicalPath = configuration["IIS_PHYSICAL_PATH"] ?? string.Empty;
+            ApplicationVirtualPath = configuration["IIS_APPLICATION_VIRTUAL_PATH"] ?? string.Empty;
+            ApplicationId = configuration["IIS_APPLICATION_ID"] ?? string.Empty;
+            SiteName = configuration["IIS_SITE_NAME"] ?? string.Empty;
+        }
+
+        public Version IISVersion { get; } = null!;
+
+        public string AppPoolId { get; }
+
+        public string AppPoolConfigFile { get; }
+
+        public string AppConfigPath { get; }
+
+        public string ApplicationPhysicalPath { get; }
+
+        public string ApplicationVirtualPath { get; }
+
+        public string ApplicationId { get; }
+
+        public string SiteName { get; }
+
+        public uint SiteId { get; }
+    }
 }

test/Microsoft.AspNetCore.SystemWebAdapters.CoreServices.Tests/HttpRuntimeIntegrationTests.cs

@@ -0,0 +1,92 @@
+// 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.Generic;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Server.IIS;
+using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Options;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.SystemWebAdapters;
+
+public class HttpRuntimeIntegrationTests : SelfHostedTestBase
+{
+    private const string IIS_VERSION = "IIS_Version";
+    private const string IIS_SITE_ID = "IIS_SITE_ID";
+    private const string IIS_SITE_NAME = "IIS_SITE_NAME";
+    private const string IIS_APPLICATION_VIRTUAL_PATH = "IIS_APPLICATION_VIRTUAL_PATH";
+    private const string IIS_PHYSICAL_PATH = "IIS_PHYSICAL_PATH";
+    private const string IIS_APPLICATION_ID = "IIS_APPLICATION_ID";
+    private const string IIS_APP_CONFIG_PATH = "IIS_APP_CONFIG_PATH";
+    private const string IIS_APP_POOL_CONFIG_FILE = "IIS_APP_POOL_CONFIG_FILE";
+    private const string IIS_APP_POOL_ID = "IIS_APP_POOL_ID";
+
+    [Fact]
+    public async Task ConfigureRuntimeViaConfig()
+    {
+        // Arrange
+        using var host = await GetTestHost()
+            .ConfigureAppConfiguration(config =>
+            {
+                config.AddInMemoryCollection(new Dictionary<string, string>
+                {
+                    [IIS_VERSION] = "10.0",
+                    [IIS_SITE_ID] = "1",
+                    [IIS_APP_POOL_ID] = IIS_APP_POOL_ID,
+                    [IIS_APP_POOL_CONFIG_FILE] = IIS_APP_POOL_CONFIG_FILE,
+                    [IIS_APP_CONFIG_PATH] = IIS_APP_CONFIG_PATH,
+                    [IIS_PHYSICAL_PATH] = IIS_PHYSICAL_PATH,
+                    [IIS_APPLICATION_VIRTUAL_PATH] = IIS_APPLICATION_VIRTUAL_PATH,
+                    [IIS_APPLICATION_ID] = IIS_APPLICATION_ID,
+                    [IIS_SITE_NAME] = IIS_SITE_NAME,
+                });
+            })
+            .StartAsync();
+
+        // Act
+        var options = host.Services.GetRequiredService<IOptions<SystemWebAdaptersOptions>>().Value;
+
+        // Assert
+        Assert.Equal(IIS_SITE_NAME, options.SiteName);
+        Assert.Equal(IIS_APPLICATION_VIRTUAL_PATH, options.AppDomainAppVirtualPath);
+        Assert.Equal(IIS_PHYSICAL_PATH, options.AppDomainAppPath);
+        Assert.Equal(IIS_APPLICATION_ID, options.ApplicationID);
+        Assert.True(options.IsHosted);
+    }
+
+    [Fact]
+    public async Task ConfigureRuntimeViaFeature()
+    {
+        // Arrange
+        var feature = new Mock<IIISEnvironmentFeature>();
+
+        feature.Setup(f => f.SiteName).Returns(IIS_SITE_NAME);
+        feature.Setup(f => f.ApplicationVirtualPath).Returns(IIS_APPLICATION_VIRTUAL_PATH);
+        feature.Setup(f => f.ApplicationPhysicalPath).Returns(IIS_PHYSICAL_PATH);
+        feature.Setup(f => f.ApplicationId).Returns(IIS_APPLICATION_ID);
+        feature.Setup(f => f.AppConfigPath).Returns(IIS_APP_CONFIG_PATH);
+        feature.Setup(f => f.AppPoolConfigFile).Returns(IIS_APP_POOL_CONFIG_FILE);
+        feature.Setup(f => f.AppPoolId).Returns(IIS_APP_POOL_ID);
+
+        using var host = await GetTestHost()
+            .StartAsync();
+
+        host.GetTestServer().Features.Set<IIISEnvironmentFeature>(feature.Object);
+
+        // Act
+        var options = host.Services.GetRequiredService<IOptions<SystemWebAdaptersOptions>>().Value;
+
+        // Assert
+        Assert.Equal(IIS_SITE_NAME, options.SiteName);
+        Assert.Equal(IIS_APPLICATION_VIRTUAL_PATH, options.AppDomainAppVirtualPath);
+        Assert.Equal(IIS_PHYSICAL_PATH, options.AppDomainAppPath);
+        Assert.Equal(IIS_APPLICATION_ID, options.ApplicationID);
+        Assert.True(options.IsHosted);
+    }
+}

test/Microsoft.AspNetCore.SystemWebAdapters.CoreServices.Tests/SelfHostedTestBase.cs

@@ -0,0 +1,39 @@
+// 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.Hosting;
+using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Xunit;
+
+namespace Microsoft.AspNetCore.SystemWebAdapters;
+
+[Collection(nameof(SelfHostedTests))]
+public class SelfHostedTestBase
+{
+    /// <summary>
+    /// This method starts up a host in the background that
+    /// makes it possible to initialize <see cref="HttpRuntime"/>
+    /// and <see cref="HostingEnvironment"/> with values needed 
+    /// for testing with the <paramref name="configure"/> option.
+    /// </summary>
+    /// <param name="configure">
+    /// Configuration for the hosting and runtime options.
+    /// </param>
+    protected static IHostBuilder GetTestHost()
+        => new HostBuilder()
+           .ConfigureWebHost(webBuilder =>
+           {
+               webBuilder
+                   .UseTestServer()
+                   .ConfigureServices(services =>
+                   {
+                       services.AddSystemWebAdapters();
+                   })
+                   .Configure(app =>
+                   {
+                       // No need to configure pipeline for tests
+                   });
+           });
+}