Fix route name lookup when hosted in IIS. Fixes #302.

Author: Chris Martinez

src/Microsoft.AspNet.OData.Versioning.ApiExplorer/Microsoft.AspNet.OData.Versioning.ApiExplorer.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
  <PropertyGroup>
-  <VersionPrefix>1.2.1</VersionPrefix>
+  <VersionPrefix>1.2.2</VersionPrefix>
   <AssemblyVersion>1.2.0.0</AssemblyVersion>
   <TargetFramework>net45</TargetFramework>
   <AssemblyTitle>Microsoft ASP.NET Web API Versioned API Explorer for OData v4.0</AssemblyTitle>
@@ -12,7 +12,7 @@
  </PropertyGroup>
 
  <ItemGroup>
-  <ReleaseNotes Include="Fix convention-based link generation (Issue 265)" />
+  <ReleaseNotes Include="Fix hosting in IIS (Issue 302)" />
  </ItemGroup>
 
  <ItemGroup>

src/Microsoft.AspNet.OData.Versioning.ApiExplorer/System.Web.Http/HttpRouteCollectionExtensions.cs

@@ -2,7 +2,9 @@
 {
     using System.Collections.Generic;
     using System.Diagnostics.Contracts;
+    using System.Reflection;
     using System.Web.Http.Routing;
+    using static System.Reflection.BindingFlags;
 
     static class HttpRouteCollectionExtensions
     {
@@ -11,9 +13,7 @@ internal static string GetRouteName( this HttpRouteCollection routes, IHttpRoute
             Contract.Requires( routes != null );
             Contract.Requires( route != null );
 
-            var items = new KeyValuePair<string, IHttpRoute>[routes.Count];
-
-            routes.CopyTo( items, 0 );
+            var items = CopyRouteEntries( routes );
 
             foreach ( var item in items )
             {
@@ -25,5 +25,61 @@ internal static string GetRouteName( this HttpRouteCollection routes, IHttpRoute
 
             return null;
         }
+
+        static KeyValuePair<string, IHttpRoute>[] CopyRouteEntries( HttpRouteCollection routes )
+        {
+            Contract.Requires( routes != null );
+            Contract.Ensures( Contract.Result<KeyValuePair<string, IHttpRoute>[]>() != null );
+
+            var items = new KeyValuePair<string, IHttpRoute>[routes.Count];
+
+            try
+            {
+                routes.CopyTo( items, 0 );
+            }
+            catch ( NotSupportedException ) when ( routes.GetType().FullName == "System.Web.Http.WebHost.Routing.HostedHttpRouteCollection" )
+            {
+                var keys = GetRouteKeys( routes );
+
+                for ( var i = 0; i < keys.Count; i++ )
+                {
+                    var key = keys[i];
+                    var route = routes[key];
+
+                    items[i] = new KeyValuePair<string, IHttpRoute>( key, route );
+                }
+            }
+
+            return items;
+        }
+
+        static IReadOnlyList<string> GetRouteKeys( HttpRouteCollection routes )
+        {
+            Contract.Requires( routes != null );
+            Contract.Ensures( Contract.Result<IReadOnlyList<string>>() != null );
+
+            var collection = GetKeys( routes );
+            var keys = new string[collection.Count];
+
+            collection.CopyTo( keys, 0 );
+
+            return keys;
+        }
+
+        static ICollection<string> GetKeys( HttpRouteCollection routes )
+        {
+            Contract.Requires( routes != null );
+            Contract.Ensures( Contract.Result<ICollection<string>>() != null );
+
+            // HACK: System.Web.Routing.RouteCollection doesn't expose the names associated with registered routes. The
+            // HostedHttpRouteCollection could have provided an adapter to support it, but didn't. Instead, it always throws
+            // NotSupportedException for the HttpRouteCollection.CopyTo method. This only happens when hosted on IIS. The
+            // only way to get the keys is use reflection to poke at the underlying dictionary.
+            var routeCollection = routes.GetType().GetField( "_routeCollection", Instance | NonPublic ).GetValue( routes );
+            var dictionary = routeCollection.GetType().GetField( "_namedMap", Instance | NonPublic ).GetValue( routeCollection );
+            var keys = (ICollection<string>) dictionary.GetType().GetRuntimeProperty( "Keys" ).GetValue( dictionary, null );
+
+            return keys;
+        }
     }
 }