[Fixes #4152] Add HttpOptionsAttribute

src/Microsoft.AspNetCore.Mvc.Core/HttpOptionsAttribute.cs

@@ -0,0 +1,38 @@
+// 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.Collections.Generic;
+using Microsoft.AspNetCore.Mvc.Routing;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// Identifies an action that only supports the HTTP OPTIONS method.
+    /// </summary>
+    public class HttpOptionsAttribute : HttpMethodAttribute
+    {
+        private static readonly IEnumerable<string> _supportedMethods = new string[] { "OPTIONS" };
+
+        /// <summary>
+        /// Creates a new <see cref="HttpOptionsAttribute"/>.
+        /// </summary>
+        public HttpOptionsAttribute()
+            : base(_supportedMethods)
+        {
+        }
+
+        /// <summary>
+        /// Creates a new <see cref="HttpOptionsAttribute"/> with the given route template.
+        /// </summary>
+        /// <param name="template">The route template. May not be null.</param>
+        public HttpOptionsAttribute(string template)
+            : base(_supportedMethods, template)
+        {
+            if (template == null)
+            {
+                throw new ArgumentNullException(nameof(template));
+            }
+        }
+    }
+}