Fixes [#276] Throw a nicer error when the routing services haven't been added to DI

src/Microsoft.AspNet.Routing/BuilderExtensions.cs

@@ -3,6 +3,8 @@
 
 using System;
 using Microsoft.AspNet.Routing;
+using Microsoft.AspNet.Routing.Internal;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -29,6 +31,14 @@ namespace Microsoft.AspNet.Builder
                 throw new ArgumentNullException(nameof(router));
             }
 
+            if (builder.ApplicationServices.GetService(typeof(RoutingMarkerService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    nameof(RoutingServiceCollectionExtensions.AddRouting),
+                    "ConfigureServices(...)"));
+            }
+
             return builder.UseMiddleware<RouterMiddleware>(router);
         }
     }

src/Microsoft.AspNet.Routing/DependencyInjection/RoutingServiceCollectionExtensions.cs

@@ -34,6 +34,8 @@ namespace Microsoft.Extensions.DependencyInjection
                 return provider.Create<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy(encoder));
             });
 
+            services.TryAddSingleton(typeof(RoutingMarkerService));
+
             if (configureOptions != null)
             {
                 services.Configure(configureOptions);

src/Microsoft.AspNet.Routing/Internal/RoutingMarkerService.cs

@@ -0,0 +1,15 @@
+// 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 Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.AspNet.Routing.Internal
+{
+    /// <summary>
+    /// A marker class used to determine if all the routing services were added
+    /// to the <see cref="IServiceCollection"/> before routing is configured.
+    /// </summary>
+    public class RoutingMarkerService
+    {
+    }
+}

src/Microsoft.AspNet.Routing/Properties/Resources.Designer.cs

@@ -426,6 +426,22 @@ namespace Microsoft.AspNet.Routing
             return string.Format(CultureInfo.CurrentCulture, GetString("AttributeRoute_DifferentLinkGenerationEntries_SameName"), p0);
         }
 
+        /// <summary>
+        /// Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.
+        /// </summary>
+        internal static string UnableToFindServices
+        {
+            get { return GetString("UnableToFindServices"); }
+        }
+
+        /// <summary>
+        /// Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.
+        /// </summary>
+        internal static string FormatUnableToFindServices(object p0, object p1, object p2)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("UnableToFindServices"), p0, p1, p2);
+        }
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);

src/Microsoft.AspNet.Routing/Resources.resx

@@ -195,4 +195,7 @@
   <data name="AttributeRoute_DifferentLinkGenerationEntries_SameName" xml:space="preserve">
     <value>Two or more routes named '{0}' have different templates.</value>
   </data>
+  <data name="UnableToFindServices" xml:space="preserve">
+    <value>Unable to find the required services. Please add all the required services by calling '{0}.{1}' inside the call to '{2}' in the application startup code.</value>
+  </data>
 </root>

src/Microsoft.AspNet.Routing/RouteBuilder.cs

@@ -4,6 +4,8 @@
 using System;
 using System.Collections.Generic;
 using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Routing.Internal;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNet.Routing
 {
@@ -21,6 +23,14 @@ namespace Microsoft.AspNet.Routing
                 throw new ArgumentNullException(nameof(applicationBuilder));
             }
 
+            if (applicationBuilder.ApplicationServices.GetService(typeof(RoutingMarkerService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    nameof(RoutingServiceCollectionExtensions.AddRouting),
+                    "ConfigureServices(...)"));
+            }
+
             ApplicationBuilder = applicationBuilder;
             ServiceProvider = applicationBuilder.ApplicationServices;
 

test/Microsoft.AspNet.Routing.Tests/BuilderExtensionsTest.cs

@@ -0,0 +1,35 @@
+// 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.AspNet.Routing;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Builder
+{
+    public class BuilderExtensionsTest
+    {
+        [Fact]
+        public void UseRouter_ThrowsInvalidOperationException_IfRoutingMarkerServiceIsNotRegistered()
+        {
+            // Arrange
+            var applicationBuilderMock = new Mock<IApplicationBuilder>();
+            applicationBuilderMock
+                .Setup(s => s.ApplicationServices)
+                .Returns(Mock.Of<IServiceProvider>());
+
+            var router = Mock.Of<IRouter>();
+            
+            // Act & Assert
+            var exception = Assert.Throws<InvalidOperationException>(
+                () => applicationBuilderMock.Object.UseRouter(router));
+
+            Assert.Equal(
+                "Unable to find the required services. Please add all the required services by calling " +
+                "'IServiceCollection.AddRouting' inside the call to 'ConfigureServices(...)'" +
+                " in the application startup code.",
+                exception.Message);
+        }
+    }
+}

test/Microsoft.AspNet.Routing.Tests/RouteBuilderTest.cs

@@ -0,0 +1,32 @@
+// 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.AspNet.Builder;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Routing
+{
+    public class RouteBuilderTest
+    {
+        [Fact]
+        public void Ctor_ThrowsInvalidOperationException_IfRoutingMarkerServiceIsNotRegistered()
+        {
+            // Arrange
+            var applicationBuilderMock = new Mock<IApplicationBuilder>();
+            applicationBuilderMock
+                .Setup(s => s.ApplicationServices)
+                .Returns(Mock.Of<IServiceProvider>());
+
+            // Act & Assert
+            var exception = Assert.Throws<InvalidOperationException>(() => new RouteBuilder(applicationBuilderMock.Object));
+
+            Assert.Equal(
+                "Unable to find the required services. Please add all the required services by calling " +
+                "'IServiceCollection.AddRouting' inside the call to 'ConfigureServices(...)'" +
+                " in the application startup code.",
+                exception.Message);
+        }
+    }
+}

test/Microsoft.AspNet.Routing.Tests/RouteTest.cs

@@ -9,6 +9,7 @@ using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Internal;
 using Microsoft.AspNet.Routing.Constraints;
+using Microsoft.AspNet.Routing.Internal;
 using Microsoft.AspNet.Testing;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -1578,6 +1579,7 @@ namespace Microsoft.AspNet.Routing
         {
             var services = new ServiceCollection();
             services.AddSingleton<IInlineConstraintResolver>(_inlineConstraintResolver);
+            services.AddSingleton<RoutingMarkerService>();
 
             var applicationBuilder = Mock.Of<IApplicationBuilder>();
             applicationBuilder.ApplicationServices = services.BuildServiceProvider();

test/Microsoft.AspNet.Routing.Tests/TemplateParserDefaultValuesTests.cs

@@ -3,6 +3,7 @@
 
 using System;
 using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Routing.Internal;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
 using Moq;
@@ -112,6 +113,7 @@ namespace Microsoft.AspNet.Routing.Tests
         {
             var services = new ServiceCollection();
             services.AddSingleton<IInlineConstraintResolver>(_inlineConstraintResolver);
+            services.AddSingleton<RoutingMarkerService>();
 
             var applicationBuilder = Mock.Of<IApplicationBuilder>();
             applicationBuilder.ApplicationServices = services.BuildServiceProvider();