Add feature to expose IIS hosting details

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/AspNetCore.vcxproj

@@ -35,6 +35,7 @@
     <ClInclude Include="AppOfflineApplication.h" />
     <ClInclude Include="AppOfflineHandler.h" />
     <ClInclude Include="DisconnectHandler.h" />
+    <ClInclude Include="ModuleEnvironment.h" />
     <ClInclude Include="ShimOptions.h" />
     <ClInclude Include="globalmodule.h" />
     <ClInclude Include="resource.h" />
@@ -49,6 +50,7 @@
     <ClCompile Include="AppOfflineApplication.cpp" />
     <ClCompile Include="AppOfflineHandler.cpp" />
     <ClCompile Include="DisconnectHandler.cpp" />
+    <ClCompile Include="ModuleEnvironment.cpp" />
     <ClCompile Include="ShimOptions.cpp" />
     <ClCompile Include="dllmain.cpp" />
     <ClCompile Include="globalmodule.cpp" />

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/ModuleEnvironment.cpp

@@ -0,0 +1,58 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+#include "ModuleEnvironment.h"
+#include <string>
+#include <sstream>
+
+// Set in the RegisterModule call IIS uses to initiate the module
+extern DWORD g_dwIISServerVersion;
+
+static std::wstring GetIISVersion() {
+    int major = (int)(g_dwIISServerVersion >> 16);
+    int minor = (int)(g_dwIISServerVersion & 0xffff);
+
+    std::wstringstream version;
+    version << major << "." << minor;
+
+    return version.str();
+}
+
+static std::wstring ToVirtualPath(const std::wstring& configurationPath) {
+    int segments = 0;
+    size_t position = configurationPath.find('/');
+
+    // Skip first 4 segments of config path
+    while (segments != 3 && position != std::wstring::npos)
+    {
+        segments++;
+        position = configurationPath.find('/', position + 1);
+    }
+
+    if (position != std::wstring::npos)
+    {
+        return configurationPath.substr(position);
+    }
+
+    return L"/";
+}
+
+void SetApplicationEnvironmentVariables(_In_ IHttpServer &server, _In_ IHttpContext &pHttpContext) {
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_VERSION", GetIISVersion().c_str());
+
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_APP_POOL_ID", server.GetAppPoolName());
+
+    IHttpServer2* server2;
+    if (SUCCEEDED(HttpGetExtendedInterface(&server, &server, &server2))) {
+        SetEnvironmentVariable(L"ASPNETCORE_IIS_APP_POOL_CONFIG_FILE", server2->GetAppPoolConfigFile());
+    }
+
+    IHttpSite* site = pHttpContext.GetSite();
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_SITE_NAME", site->GetSiteName());
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_SITE_ID", std::to_wstring(site->GetSiteId()).c_str());
+
+    IHttpApplication* app = pHttpContext.GetApplication();
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_APP_CONFIG_PATH", app->GetAppConfigPath());
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_APPLICATION_ID", app->GetApplicationId());
+    SetEnvironmentVariable(L"ASPNETCORE_IIS_APPLICATION_VIRTUAL_PATH", ToVirtualPath(app->GetAppConfigPath()).c_str());
+}

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/ModuleEnvironment.h

@@ -0,0 +1,6 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+#pragma once
+
+void SetApplicationEnvironmentVariables(_In_ IHttpServer& server, _In_ IHttpContext& pHttpContext);

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/applicationinfo.cpp

@@ -16,6 +16,7 @@
 #include "ConfigurationLoadException.h"
 #include "resource.h"
 #include "file_utility.h"
+#include "ModuleEnvironment.h"
 
 extern HINSTANCE           g_hServerModule;
 extern BOOL                g_fInAppOfflineShutdown;
@@ -72,6 +73,8 @@ APPLICATION_INFO::CreateHandler(
 HRESULT
 APPLICATION_INFO::CreateApplication(IHttpContext& pHttpContext)
 {
+    SetApplicationEnvironmentVariables(m_pServer, pHttpContext);
+
     auto& pHttpApplication = *pHttpContext.GetApplication();
     if (AppOfflineApplication::ShouldBeStarted(pHttpApplication))
     {

src/Servers/IIS/AspNetCoreModuleV2/AspNetCore/dllmain.cpp

@@ -19,6 +19,7 @@ BOOL                g_fRecycleProcessCalled = FALSE;
 BOOL                g_fInShutdown = FALSE;
 BOOL                g_fInAppOfflineShutdown = FALSE;
 HINSTANCE           g_hServerModule;
+DWORD               g_dwIISServerVersion;
 
 VOID
 StaticCleanup()
@@ -90,7 +91,7 @@ HRESULT
 
 --*/
 {
-    UNREFERENCED_PARAMETER(dwServerVersion);
+    g_dwIISServerVersion = dwServerVersion;
 
     if (pHttpServer->IsCommandLineLaunch())
     {

src/Servers/IIS/IIS/samples/NativeIISSample/Startup.cs

@@ -96,11 +96,32 @@ public void Configure(IApplicationBuilder app)
             }
 
             await context.Response.WriteAsync(Environment.NewLine);
-            var addresses = context.RequestServices.GetService<IServer>().Features.Get<IServerAddressesFeature>();
+            var server = context.RequestServices.GetService<IServer>();
+
+            var addresses = server.Features.Get<IServerAddressesFeature>();
             foreach (var key in addresses.Addresses)
             {
                 await context.Response.WriteAsync(key + Environment.NewLine);
             }
+
+            if (server.Features.Get<IIISEnvironmentFeature>() is { } envFeature)
+            {
+                await context.Response.WriteAsync(Environment.NewLine);
+                await context.Response.WriteAsync("IIS Environment Information:" + Environment.NewLine);
+                await context.Response.WriteAsync("IIS Version: " + envFeature.IISVersion + Environment.NewLine);
+                await context.Response.WriteAsync("ApplicationId: " + envFeature.ApplicationId + Environment.NewLine);
+                await context.Response.WriteAsync("Application Path: " + envFeature.ApplicationPhysicalPath + Environment.NewLine);
+                await context.Response.WriteAsync("Application Virtual Path: " + envFeature.ApplicationVirtualPath + Environment.NewLine);
+                await context.Response.WriteAsync("Application Config Path: " + envFeature.AppConfigPath + Environment.NewLine);
+                await context.Response.WriteAsync("AppPool ID: " + envFeature.AppPoolId + Environment.NewLine);
+                await context.Response.WriteAsync("AppPool Config File: " + envFeature.AppPoolConfigFile + Environment.NewLine);
+                await context.Response.WriteAsync("Site ID: " + envFeature.SiteId + Environment.NewLine);
+                await context.Response.WriteAsync("Site Name: " + envFeature.SiteName + Environment.NewLine);
+            }
+            else
+            {
+                await context.Response.WriteAsync($"No {nameof(IIISEnvironmentFeature)} available." + Environment.NewLine);
+            }
         });
     }
 

src/Servers/IIS/IIS/src/Core/IISEnvironmentFeature.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 System.Diagnostics.CodeAnalysis;
+using Microsoft.Extensions.Configuration;
+
+namespace Microsoft.AspNetCore.Server.IIS.Core;
+
+internal 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; }
+}

src/Servers/IIS/IIS/src/Core/IISHttpServer.cs

@@ -9,6 +9,7 @@
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Hosting.Server.Features;
 using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
@@ -58,6 +59,7 @@ public IISHttpServer(
         IISNativeApplication nativeApplication,
         IHostApplicationLifetime applicationLifetime,
         IAuthenticationSchemeProvider authentication,
+        IConfiguration configuration,
         IOptions<IISServerOptions> options,
         ILogger<IISHttpServer> logger
         )
@@ -77,6 +79,11 @@ ILogger<IISHttpServer> logger
 
         Features.Set<IServerAddressesFeature>(_serverAddressesFeature);
 
+        if (IISEnvironmentFeature.TryCreate(configuration, out var iisEnvFeature))
+        {
+            Features.Set<IIISEnvironmentFeature>(iisEnvFeature);
+        }
+
         if (_options.MaxRequestBodySize > _options.IisMaxRequestSizeLimit)
         {
             _logger.LogWarning(CoreStrings.MaxRequestLimitWarning);

src/Servers/IIS/IIS/src/IIISEnvironmentFeature.cs

@@ -0,0 +1,55 @@
+// 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.Server.IIS;
+
+/// <summary>
+/// This feature provides access to IIS application information
+/// </summary>
+public 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; }
+}

src/Servers/IIS/IIS/src/PublicAPI.Unshipped.txt

@@ -26,4 +26,14 @@
 *REMOVED*override Microsoft.AspNetCore.Server.IIS.Core.WriteOnlyStream.ReadTimeout.get -> int
 *REMOVED*override Microsoft.AspNetCore.Server.IIS.Core.WriteOnlyStream.ReadTimeout.set -> void
 *REMOVED*override Microsoft.AspNetCore.Server.IIS.Core.WriteOnlyStream.Seek(long offset, System.IO.SeekOrigin origin) -> long
-*REMOVED*override Microsoft.AspNetCore.Server.IIS.Core.WriteOnlyStream.SetLength(long value) -> void
+*REMOVED*override Microsoft.AspNetCore.Server.IIS.Core.WriteOnlyStream.SetLength(long value) -> void
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.AppConfigPath.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.ApplicationId.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.ApplicationPhysicalPath.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.ApplicationVirtualPath.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.AppPoolConfigFile.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.AppPoolId.get -> string!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.IISVersion.get -> System.Version!
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.SiteId.get -> uint
+Microsoft.AspNetCore.Server.IIS.IIISEnvironmentFeature.SiteName.get -> string!

src/Servers/IIS/IIS/test/Common.FunctionalTests/RequestResponseTests.cs

@@ -611,6 +611,28 @@ public async Task HostingEnvironmentIsCorrect()
         Assert.Equal(_fixture.DeploymentResult.ContentRoot + "\\", await _fixture.Client.GetStringAsync("/ASPNETCORE_IIS_PHYSICAL_PATH"));
     }
 
+    [ConditionalTheory]
+    [InlineData("IIISEnvironmentFeature")]
+    [InlineData("IIISEnvironmentFeatureConfig")]
+    public async Task IISEnvironmentFeatureIsAvailable(string endpoint)
+    {
+        var siteName = _fixture.DeploymentResult.DeploymentParameters.SiteName.ToUpperInvariant();
+
+        var expected = $"""
+            IIS Version: 10.0
+            ApplicationId: /LM/W3SVC/1/ROOT
+            Application Path: {_fixture.DeploymentResult.ContentRoot}\
+            Application Virtual Path: /
+            Application Config Path: MACHINE/WEBROOT/APPHOST/{siteName}
+            AppPool ID: {_fixture.DeploymentResult.AppPoolName}
+            AppPool Config File: {_fixture.DeploymentResult.DeploymentParameters.ServerConfigLocation}
+            Site ID: 1
+            Site Name: {siteName}
+            """;
+
+        Assert.Equal(expected, await _fixture.Client.GetStringAsync($"/{endpoint}"));
+    }
+
     [ConditionalTheory]
     [InlineData(65000)]
     [InlineData(1000000)]