Parse Path and PathBase from Virtual Directory. (#457)

src/Microsoft.AspNetCore.Server.IISIntegration/NativeMethods.cs

@@ -75,8 +75,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
         public unsafe static extern bool http_set_managed_context(IntPtr pHttpContext, IntPtr pvManagedContext);
 
         [DllImport(AspNetCoreModuleDll)]
-        [return: MarshalAs(UnmanagedType.BStr)]
-        public unsafe static extern string http_get_application_full_path();
+        public unsafe static extern int http_get_application_paths([MarshalAs(UnmanagedType.BStr)] out string fullPath, [MarshalAs(UnmanagedType.BStr)] out string virtualPath);
 
         [DllImport(AspNetCoreModuleDll)]
         public unsafe static extern bool http_shutdown();

src/Microsoft.AspNetCore.Server.IISIntegration/Server/IISHttpContext.cs

@@ -67,7 +67,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
             _pipeFactory = pipeFactory;
             _pHttpContext = pHttpContext;
 
-            NativeMethods.http_set_managed_context(pHttpContext, (IntPtr)_thisHandle);
+            NativeMethods.http_set_managed_context(_pHttpContext, (IntPtr)_thisHandle);
             unsafe
             {
                 Method = GetVerb();
@@ -80,27 +80,17 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
 
                 var originalPath = RequestUriBuilder.DecodeAndUnescapePath(GetRawUrlInBytes());
 
-                // TODO: Read this from IIS config
-                // See https://github.com/aspnet/IISIntegration/issues/427
-                var prefix = "/";
                 if (KnownMethod == HttpApiTypes.HTTP_VERB.HttpVerbOPTIONS && string.Equals(RawTarget, "*", StringComparison.Ordinal))
                 {
                     PathBase = string.Empty;
                     Path = string.Empty;
                 }
-                // These paths are both unescaped already.
-                else if (originalPath.Length == prefix.Length - 1)
-                {
-                    // They matched exactly except for the trailing slash.
-                    PathBase = originalPath;
-                    Path = string.Empty;
-                }
                 else
                 {
-                    // url: /base/path, prefix: /base/, base: /base, path: /path
-                    // url: /, prefix: /, base: , path: /
-                    PathBase = originalPath.Substring(0, prefix.Length - 1);
-                    Path = originalPath.Substring(prefix.Length - 1);
+                    // Path and pathbase are unescaped by RequestUriBuilder
+                    // The UsePathBase middleware will modify the pathbase and path correctly
+                    PathBase = string.Empty;
+                    Path = originalPath;
                 }
 
                 var cookedUrl = GetCookedUrl();

src/Microsoft.AspNetCore.Server.IISIntegration/Server/IISHttpServer.cs

@@ -9,7 +9,6 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Http.Features;
-using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Server.IISIntegration
 {
@@ -38,7 +37,6 @@ namespace Microsoft.AspNetCore.Server.IISIntegration
             _iisContextFactory = new IISContextFactory<TContext>(_pipeFactory, application);
 
             // Start the server by registering the callback
-            // TODO the context may change here for shutdown.
             NativeMethods.register_callbacks(_requestHandler, _shutdownHandler, _onAsyncCompletion, (IntPtr)_httpServerHandle, (IntPtr)_httpServerHandle);
 
             return Task.CompletedTask;

src/Microsoft.AspNetCore.Server.IISIntegration/Server/IISServerSetupFilter.cs

@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+
+namespace Microsoft.AspNetCore.Server.IISIntegration
+{
+    internal class IISServerSetupFilter : IStartupFilter
+    {
+        private string _virtualPath;
+
+        public IISServerSetupFilter(string virtualPath)
+        {
+            _virtualPath = virtualPath;
+        }
+
+        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
+        {
+            return app =>
+            {
+                app.UsePathBase(_virtualPath);
+                next(app);
+            };
+        }
+    }
+}

src/Microsoft.AspNetCore.Server.IISIntegration/WebHostBuilderIISExtensions.cs

@@ -45,11 +45,19 @@ namespace Microsoft.AspNetCore.Hosting
                 hostBuilder.UseSetting(nameof(UseIISIntegration), "true");
                 hostBuilder.CaptureStartupErrors(true);
 
-                var applicationPath = NativeMethods.http_get_application_full_path();
-                hostBuilder.UseContentRoot(applicationPath);
+                // TODO consider adding a configuration load where all variables needed are loaded from ANCM in one call.
+                var hResult = NativeMethods.http_get_application_paths(out var fullPath, out var virtualPath);
+                var exception = Marshal.GetExceptionForHR(hResult);
+                if (exception != null)
+                {
+                    throw exception;
+                }
+
+                hostBuilder.UseContentRoot(fullPath);
                 return hostBuilder.ConfigureServices(services =>
                 {
                     services.AddSingleton<IServer, IISHttpServer>();
+                    services.AddSingleton<IStartupFilter>(new IISServerSetupFilter(virtualPath));
                     services.AddAuthenticationCore();
                 });
             }