[Fixes #33]AddCors should adopt new pattern

samples/UseOptions/Startup.cs

@@ -9,9 +9,7 @@ namespace UseOptions
     {
         public void ConfigureServices(IServiceCollection services)
         {
-            services.AddCors();
+            services.AddCors(options =>
-            services.ConfigureCors(
-                options =>
                     options.AddPolicy("allowSingleOrigin", builder => builder.WithOrigins("http://example.com")));
         }
 

src/Microsoft.AspNet.Cors.Core/CorsServiceCollectionExtensions.cs

@@ -2,8 +2,11 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.AspNet.Cors;
 using Microsoft.AspNet.Cors.Core;
+using Microsoft.Framework.Configuration;
 using Microsoft.Framework.DependencyInjection.Extensions;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.Framework.DependencyInjection
 {
@@ -13,12 +16,30 @@ namespace Microsoft.Framework.DependencyInjection
     public static class CorsServiceCollectionExtensions
     {
         /// <summary>
-        /// Can be used to configure services in the <paramref name="serviceCollection"/>.
+        /// Add services needed to support CORS to the given <paramref name="serviceCollection"/>.
         /// </summary>
-        /// <param name="serviceCollection">The service collection which needs to be configured.</param>
+        /// <param name="serviceCollection">The service collection to which CORS services are added.</param>
+        /// <returns>The updated <see cref="IServiceCollection"/>.</returns>
+        public static IServiceCollection AddCors(this IServiceCollection serviceCollection)
+        {
+            if (serviceCollection == null)
+            {
+                throw new ArgumentNullException(nameof(serviceCollection));
+            }
+
+            serviceCollection.AddOptions();
+            serviceCollection.TryAdd(ServiceDescriptor.Transient<ICorsService, CorsService>());
+            serviceCollection.TryAdd(ServiceDescriptor.Transient<ICorsPolicyProvider, DefaultCorsPolicyProvider>());
+            return serviceCollection;
+        }
+
+        /// <summary>
+        /// Add services needed to support CORS to the given <paramref name="serviceCollection"/>.
+        /// </summary>
+        /// <param name="serviceCollection">The service collection to which CORS services are added.</param>
         /// <param name="configure">A delegate which is run to configure the services.</param>
-        /// <returns></returns>
+        /// <returns>The updated <see cref="IServiceCollection"/>.</returns>
-        public static IServiceCollection ConfigureCors(
+        public static IServiceCollection AddCors(
             this IServiceCollection serviceCollection,
             Action<CorsOptions> configure)
         {
@@ -32,20 +53,8 @@ namespace Microsoft.Framework.DependencyInjection
                 throw new ArgumentNullException(nameof(configure));
             }
 
-            return serviceCollection.Configure(configure);
+            serviceCollection.Configure(configure);
-        }
+            return serviceCollection.AddCors();
-
-        /// <summary>
-        /// Add services needed to support CORS to the given <paramref name="serviceCollection"/>.
-        /// </summary>
-        /// <param name="serviceCollection">The service collection to which CORS services are added.</param>
-        /// <returns>The updated <see cref="IServiceCollection"/>.</returns>
-        public static IServiceCollection AddCors(this IServiceCollection serviceCollection)
-        {
-            serviceCollection.AddOptions();
-            serviceCollection.TryAdd(ServiceDescriptor.Transient<ICorsService, CorsService>());
-            serviceCollection.TryAdd(ServiceDescriptor.Transient<ICorsPolicyProvider, DefaultCorsPolicyProvider>());
-            return serviceCollection;
         }
     }
 }

test/Microsoft.AspNet.Cors.Test/CorsMiddlewareTests.cs

@@ -23,7 +23,7 @@ namespace Microsoft.AspNet.Cors.Test
             // Arrange
             using (var server = TestServer.Create(app =>
             {
-                app.UseCors(builder => 
+                app.UseCors(builder =>
                     builder.WithOrigins("http://localhost:5001")
                            .WithMethods("PUT")
                            .WithHeaders("Header1")
@@ -70,8 +70,7 @@ namespace Microsoft.AspNet.Cors.Test
             },
             services =>
             {
-                services.AddCors();
+                services.AddCors(options =>
-                services.ConfigureCors(options =>
                 {
                     options.AddPolicy("customPolicy", policy);
                 });
@@ -129,7 +128,7 @@ namespace Microsoft.AspNet.Cors.Test
             // Arrange
             using (var server = TestServer.Create(app =>
             {
-                app.UseCors(builder => 
+                app.UseCors(builder =>
                     builder.WithOrigins("http://localhost:5001")
                            .WithMethods("PUT")
                            .WithHeaders("Header1")
@@ -156,7 +155,7 @@ namespace Microsoft.AspNet.Cors.Test
         [Fact]
         public async Task Uses_PolicyProvider_AsFallback()
         {
-            // Arrange 
+            // Arrange
             var corsService = Mock.Of<ICorsService>();
             var mockProvider = new Mock<ICorsPolicyProvider>();
             mockProvider.Setup(o => o.GetPolicyAsync(It.IsAny<HttpContext>(), It.IsAny<string>()))
@@ -184,7 +183,7 @@ namespace Microsoft.AspNet.Cors.Test
         [Fact]
         public async Task DoesNotSetHeaders_ForNoPolicy()
         {
-            // Arrange 
+            // Arrange
             var corsService = Mock.Of<ICorsService>();
             var mockProvider = new Mock<ICorsPolicyProvider>();
             mockProvider.Setup(o => o.GetPolicyAsync(It.IsAny<HttpContext>(), It.IsAny<string>()))