Check dispatcher services registered (#610)

src/Microsoft.AspNetCore.Routing/Builder/DispatcherApplicationBuilderExtensions.cs

@@ -1,7 +1,10 @@
 // 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.Routing;
+using Microsoft.AspNetCore.Routing.Internal;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Builder
 {
@@ -9,12 +12,29 @@ namespace Microsoft.AspNetCore.Builder
     {
         public static IApplicationBuilder UseDispatcher(this IApplicationBuilder builder)
         {
+            VerifyDispatcherIsRegistered(builder);
+
             return builder.UseMiddleware<DispatcherMiddleware>();
         }
 
         public static IApplicationBuilder UseEndpoint(this IApplicationBuilder builder)
         {
+            VerifyDispatcherIsRegistered(builder);
+
             return builder.UseMiddleware<EndpointMiddleware>();
         }
+
+        private static void VerifyDispatcherIsRegistered(IApplicationBuilder app)
+        {
+            // Verify if AddDispatcher was done before calling UseDispatcher/UseEndpoint
+            // We use the DispatcherMarkerService to make sure if all the services were added.
+            if (app.ApplicationServices.GetService(typeof(DispatcherMarkerService)) == null)
+            {
+                throw new InvalidOperationException(Resources.FormatUnableToFindServices(
+                    nameof(IServiceCollection),
+                    nameof(DispatcherServiceCollectionExtensions.AddDispatcher),
+                    "ConfigureServices(...)"));
+            }
+        }
     }
 }

src/Microsoft.AspNetCore.Routing/DependencyInjection/DispatcherServiceCollectionExtensions.cs

@@ -6,6 +6,7 @@ using System.Reflection;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.AspNetCore.Routing.EndpointConstraints;
 using Microsoft.AspNetCore.Routing.EndpointFinders;
+using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.AspNetCore.Routing.Matchers;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Options;
@@ -34,6 +35,7 @@ namespace Microsoft.Extensions.DependencyInjection
             //
             // Default matcher implementation
             //
+            services.TryAddSingleton<MatchProcessorFactory, DefaultMatchProcessorFactory>();
             services.TryAddSingleton<MatcherFactory, TreeMatcherFactory>();
 
             // Link generation related services
@@ -50,6 +52,8 @@ namespace Microsoft.Extensions.DependencyInjection
             services.TryAddEnumerable(
                 ServiceDescriptor.Transient<IEndpointConstraintProvider, DefaultEndpointConstraintProvider>());
 
+            services.TryAddSingleton(typeof(DispatcherMarkerService));
+
             return services;
         }
 

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

@@ -30,7 +30,6 @@ namespace Microsoft.Extensions.DependencyInjection
                 throw new ArgumentNullException(nameof(services));
             }
 
-            services.TryAddSingleton<MatchProcessorFactory, DefaultMatchProcessorFactory>();
             services.TryAddTransient<IInlineConstraintResolver, DefaultInlineConstraintResolver>();
             services.TryAddSingleton<ObjectPool<UriBuildingContext>>(s =>
             {

src/Microsoft.AspNetCore.Routing/Internal/DispatcherMarkerService.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.AspNetCore.Routing.Internal
+{
+    /// <summary>
+    /// A marker class used to determine if all the dispatcher services were added
+    /// to the <see cref="IServiceCollection"/> before dispatcher is configured.
+    /// </summary>
+    internal class DispatcherMarkerService
+    {
+    }
+}

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

@@ -9,7 +9,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
     /// 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
+    internal class RoutingMarkerService
     {
     }
 }

test/Microsoft.AspNetCore.Routing.Tests/DispatcherApplicationBuilderExtensions.cs

@@ -0,0 +1,103 @@
+// 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 System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder.Internal;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Builder
+{
+    public class DispatcherApplicationBuilderExtensions
+    {
+        [Fact]
+        public void UseDispatcher_ServicesNotRegistered_Throws()
+        {
+            // Arrange
+            var app = new ApplicationBuilder(Mock.Of<IServiceProvider>());
+
+            // Act
+            var ex = Assert.Throws<InvalidOperationException>(() => app.UseDispatcher());
+
+            // Assert
+            Assert.Equal(
+                "Unable to find the required services. " +
+                "Please add all the required services by calling 'IServiceCollection.AddDispatcher' " +
+                "inside the call to 'ConfigureServices(...)' in the application startup code.",
+                ex.Message);
+        }
+
+        [Fact]
+        public void UseEndpoint_ServicesNotRegistered_Throws()
+        {
+            // Arrange
+            var app = new ApplicationBuilder(Mock.Of<IServiceProvider>());
+
+            // Act
+            var ex = Assert.Throws<InvalidOperationException>(() => app.UseEndpoint());
+
+            // Assert
+            Assert.Equal(
+                "Unable to find the required services. " +
+                "Please add all the required services by calling 'IServiceCollection.AddDispatcher' " +
+                "inside the call to 'ConfigureServices(...)' in the application startup code.",
+                ex.Message);
+        }
+
+        [Fact]
+        public async Task UseDispatcher_ServicesRegistered_SetsFeature()
+        {
+            // Arrange
+            var services = CreateServices();
+
+            var app = new ApplicationBuilder(services);
+
+            app.UseDispatcher();
+
+            var appFunc = app.Build();
+            var httpContext = new DefaultHttpContext();
+
+            // Act
+            await appFunc(httpContext);
+
+            // Assert
+            Assert.NotNull(httpContext.Features.Get<IEndpointFeature>());
+        }
+
+        [Fact]
+        public async Task UseEndpoint_ServicesRegistered_SetsFeature()
+        {
+            // Arrange
+            var services = CreateServices();
+
+            var app = new ApplicationBuilder(services);
+
+            app.UseDispatcher();
+            app.UseEndpoint();
+
+            var appFunc = app.Build();
+            var httpContext = new DefaultHttpContext();
+
+            // Act
+            await appFunc(httpContext);
+
+            // Assert
+            Assert.NotNull(httpContext.Features.Get<IEndpointFeature>());
+        }
+
+        private IServiceProvider CreateServices()
+        {
+            var services = new ServiceCollection();
+
+            services.AddLogging();
+            services.AddOptions();
+            services.AddDispatcher();
+
+            return services.BuildServiceProvider();
+        }
+    }
+}