Add support for Results extension point

Author: captainsafia

src/Http/Http.Extensions/test/Microsoft.AspNetCore.Http.Extensions.Tests.csproj

@@ -12,6 +12,7 @@
 
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Http" />
+    <Reference Include="Microsoft.AspNetCore.Http.Results" />
     <Reference Include="Microsoft.AspNetCore.Http.Extensions" />
     <Reference Include="Microsoft.Extensions.DependencyInjection" />
   </ItemGroup>

src/Http/Http.Extensions/test/RequestDelegateFactoryTests.cs

@@ -19,6 +19,7 @@
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Http.Json;
 using Microsoft.AspNetCore.Http.Metadata;
+using Microsoft.AspNetCore.Http.Result;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -2240,6 +2241,35 @@ public async Task TreatsUnknownNullabilityAsOptionalForReferenceType(bool provid
 
 #nullable enable
 
+        [Fact]
+        public async Task CanExecuteRequestDelegateWithResultsExtension()
+        {
+            IResult actionWithExtensionsResult(string name) => Results.Extensions.TestResult(name);
+
+            var httpContext = new DefaultHttpContext();
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddSingleton(LoggerFactory);
+            httpContext.RequestServices = serviceCollection.BuildServiceProvider();
+            var responseBodyStream = new MemoryStream();
+            httpContext.Response.Body = responseBodyStream;
+
+            httpContext.Request.Query = new QueryCollection(new Dictionary<string, StringValues>
+            {
+                ["name"] = "Tester"
+            });
+
+            var factoryResult = RequestDelegateFactory.Create(actionWithExtensionsResult);
+
+            var requestDelegate = factoryResult.RequestDelegate;
+            await requestDelegate(httpContext);
+
+            Assert.Equal(200, httpContext.Response.StatusCode);
+            Assert.False(httpContext.RequestAborted.IsCancellationRequested);
+            var decodedResponseBody = Encoding.UTF8.GetString(responseBodyStream.ToArray());
+            Assert.Equal(@"""Hello Tester. This is from an extension method.""", decodedResponseBody);
+
+        }
+
         private class Todo : ITodo
         {
             public int Id { get; set; }
@@ -2460,4 +2490,12 @@ public RequestBodyDetectionFeature(bool canHaveBody)
             public bool CanHaveBody { get; }
         }
     }
+
+    internal static class TestExtensionResults
+    {
+        public static IResult TestResult(this IResultExtensions resultExtensions, string name)
+        {
+            return Results.Ok($"Hello {name}. This is from an extension method.");
+        }
+    }
 }

src/Http/Http.Results/src/IResultExtensions.cs

@@ -0,0 +1,11 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Http.Result
+{
+    /// <summary>
+    /// Provides an interface for registering external methods that provide
+    /// custom <see cref="IResult" /> instances.
+    /// </summary>
+    public interface IResultExtensions { }
+}

src/Http/Http.Results/src/PublicAPI.Unshipped.txt

@@ -31,3 +31,5 @@ static Microsoft.AspNetCore.Http.Results.Text(string! content, string? contentTy
 static Microsoft.AspNetCore.Http.Results.Unauthorized() -> Microsoft.AspNetCore.Http.IResult!
 static Microsoft.AspNetCore.Http.Results.UnprocessableEntity(object? error = null) -> Microsoft.AspNetCore.Http.IResult!
 static Microsoft.AspNetCore.Http.Results.ValidationProblem(System.Collections.Generic.IDictionary<string!, string![]!>! errors, string? detail = null, string? instance = null, int? statusCode = null, string? title = null, string? type = null) -> Microsoft.AspNetCore.Http.IResult!
+static Microsoft.AspNetCore.Http.Results.Extensions.get -> Microsoft.AspNetCore.Http.Result.IResultExtensions!
+Microsoft.AspNetCore.Http.Result.IResultExtensions

src/Http/Http.Results/src/ResultExtensions.cs

@@ -0,0 +1,11 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Http.Result
+{
+    /// <summary>
+    /// Implements an interface for registering external methods that provide
+    /// custom <see cref="IResult"/> instances.
+    /// </summary>
+    internal sealed class ResultExtensions : IResultExtensions { }
+}

src/Http/Http.Results/src/Results.cs

@@ -588,5 +588,11 @@ public static IResult Accepted(string? uri = null, object? value = null)
         /// <returns>The created <see cref="IResult"/> for the response.</returns>
         public static IResult AcceptedAtRoute(string? routeName = null, object? routeValues = null, object? value = null)
             => new AcceptedAtRouteResult(routeName, routeValues, value);
+
+        /// <summary>
+        /// Provides a place for external libraries to extend the default <see cref="Results"/> set
+        /// via extension methods returning custom <see cref="IResult" /> implementations.
+        /// </summary>
+        public static IResultExtensions Extensions { get; } = new ResultExtensions();
     }
 }