Added header to result, and test

Author: drewgillies

src/NuGetGallery/Controllers/PackagesController.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Diagnostics;
 using System.Globalization;
 using System.IO;
@@ -796,8 +797,10 @@ private static async Task<byte[]> ReadPackageFile(PackageArchiveReader packageAr
             }
         }
 
+        // This additional delete action addresses issue https://github.com/NuGet/Engineering/issues/2866 - we need to error out.
         [HttpDelete]
-        public HttpStatusCodeResult DisplayPackage() => new HttpStatusCodeResult(HttpStatusCode.MethodNotAllowed);
+        public HttpStatusCodeResult DisplayPackage() 
+            => new HttpStatusCodeWithHeadersResult(HttpStatusCode.MethodNotAllowed, new NameValueCollection() { { "allow", "GET" } });
 
         [HttpGet]
         public virtual async Task<ActionResult> DisplayPackage(string id, string version)

src/NuGetGallery/Infrastructure/HttpStatusCodeWithHeadersResult.cs

@@ -0,0 +1,27 @@
+// 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.Collections.Specialized;
+using System.Net;
+using System.Web.Mvc;
+
+namespace NuGetGallery
+{
+    public class HttpStatusCodeWithHeadersResult : HttpStatusCodeResult
+    {
+        public readonly NameValueCollection Headers;
+
+        public HttpStatusCodeWithHeadersResult(HttpStatusCode statusCode, NameValueCollection headers)
+            : base(statusCode)
+        {
+            Headers = headers;
+        }
+
+        public override void ExecuteResult(ControllerContext context)
+        {
+            base.ExecuteResult(context);
+            var response = context.RequestContext.HttpContext.Response;
+            response.Headers.Add(Headers);
+        }
+    }
+}

src/NuGetGallery/NuGetGallery.csproj

@@ -227,6 +227,7 @@
     <Compile Include="Infrastructure\ABTestEnrollmentFactory.cs" />
     <Compile Include="Infrastructure\CookieBasedABTestService.cs" />
     <Compile Include="Infrastructure\RequestValidationExceptionFilter.cs" />
+    <Compile Include="Infrastructure\HttpStatusCodeWithHeadersResult.cs" />
     <Compile Include="Infrastructure\IABTestEnrollmentFactory.cs" />
     <Compile Include="Infrastructure\IABTestService.cs" />
     <Compile Include="Infrastructure\ILuceneDocumentFactory.cs" />

tests/NuGetGallery.Facts/Controllers/ControllerTests.cs

@@ -74,6 +74,7 @@ public void AllActionsHaveAntiForgeryTokenIfNotGet()
                 new ControllerActionRuleException(typeof(ApiController), nameof(ApiController.DeletePackage)),
                 new ControllerActionRuleException(typeof(ApiController), nameof(ApiController.PublishPackage)),
                 new ControllerActionRuleException(typeof(ApiController), nameof(ApiController.DeprecatePackage)),
+                new ControllerActionRuleException(typeof(PackagesController), nameof(PackagesController.DisplayPackage)),
             };
 
             // Act

tests/NuGetGallery.Facts/Controllers/PackagesControllerFacts.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Globalization;
 using System.IO;
 using System.Linq;
@@ -498,6 +499,19 @@ public async Task GivenANonExistentPackageIt404s()
                 ResultAssert.IsNotFound(result);
             }
 
+            [Fact]
+            public void GivenADeleteMethodIt405sWithAllowHeader()
+            {
+                // Arrange
+                var controller = CreateController(GetConfigurationService());
+
+                // Act
+                var result = controller.DisplayPackage();
+
+                // Assert
+                ResultAssert.IsStatusCodeWithHeaders(result, HttpStatusCode.MethodNotAllowed, new NameValueCollection() { { "allow", "GET" } });
+            }
+
             public static IEnumerable<PackageStatus> ValidatingPackageStatuses =
                 new[] { PackageStatus.Validating, PackageStatus.FailedValidation };
 

tests/NuGetGallery.Facts/TestUtils/ResultAssert.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 using System;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Net;
 using System.Web.Mvc;
 using System.Web.Routing;
@@ -127,6 +128,19 @@ public static HttpStatusCodeResult IsStatusCode(ActionResult result, int statusC
             return statusCodeResult;
         }
 
+        public static HttpStatusCodeWithHeadersResult IsStatusCodeWithHeaders(ActionResult result, HttpStatusCode statusCode, NameValueCollection headers)
+        {
+            var statusCodeResult = Assert.IsAssignableFrom<HttpStatusCodeWithHeadersResult>(result);
+            Assert.Equal((int)statusCode, statusCodeResult.StatusCode);
+
+            foreach (var key in headers.AllKeys)
+            {
+                Assert.Equal(headers.Get(key), statusCodeResult.Headers.Get(key));
+            }
+
+            return statusCodeResult;
+        }
+
         public static EmptyResult IsEmpty(ActionResult result)
         {
             return Assert.IsType<EmptyResult>(result);