Hoist method attributes from the request delegate as metadata. (#6911)

- This should allow a more declarative approach to declaring endpoint metadata using the default methods.
- Attributes are applied first and can be overridden imperatively

src/Http/Routing/src/Builder/EndpointRouteBuilderExtensions.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.AspNetCore.Routing.Patterns;
@@ -21,7 +22,6 @@ namespace Microsoft.AspNetCore.Builder
         private static readonly string[] PutVerb = new[] { "PUT" };
         private static readonly string[] DeleteVerb = new[] { "DELETE" };
 
-        #region MapVerbs
         /// <summary>
         /// Adds a <see cref="RouteEndpoint"/> to the <see cref="IEndpointRouteBuilder"/> that matches HTTP GET requests
         /// for the specified pattern.
@@ -227,9 +227,7 @@ namespace Microsoft.AspNetCore.Builder
 
             return Map(builder, pattern, displayName ?? $"{pattern} HTTP: {string.Join(", ", httpMethods)}", requestDelegate, metadata: resolvedMetadata.ToArray());
         }
-        #endregion
 
-        #region Map
         /// <summary>
         /// Adds a <see cref="RouteEndpoint"/> to the <see cref="IEndpointRouteBuilder"/> that matches HTTP requests
         /// for the specified pattern.
@@ -323,8 +321,17 @@ namespace Microsoft.AspNetCore.Builder
             var routeEndpointBuilder = new RouteEndpointBuilder(
                 requestDelegate,
                 pattern,
-                defaultOrder);
-            routeEndpointBuilder.DisplayName = displayName;
+                defaultOrder)
+            {
+                DisplayName = displayName
+            };
+
+            // Add delegate attributes as metadata
+            foreach (var attribute in requestDelegate.Method.GetCustomAttributes())
+            {
+                routeEndpointBuilder.Metadata.Add(attribute);
+            }
+
             if (metadata != null)
             {
                 foreach (var item in metadata)
@@ -343,6 +350,5 @@ namespace Microsoft.AspNetCore.Builder
 
             return modelEndpointDataSource.AddEndpointBuilder(routeEndpointBuilder);
         }
-        #endregion
     }
 }

src/Http/Routing/test/UnitTests/Builder/MapEndpointEndpointDataSourceBuilderExtensionsTest.cs

@@ -2,11 +2,9 @@
 // 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.Text;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
-using Microsoft.AspNetCore.Routing.Matching;
 using Microsoft.AspNetCore.Routing.Patterns;
 using Xunit;
 
@@ -97,5 +95,59 @@ namespace Microsoft.AspNetCore.Builder
             Assert.Equal("/", endpointBuilder1.RoutePattern.RawText);
             Assert.Equal(metadata, Assert.Single(endpointBuilder1.Metadata));
         }
+
+        [Fact]
+        public void MapEndpoint_AttributesCollectedAsMetadata()
+        {
+            // Arrange
+            var builder = new DefaultEndpointRouteBuilder();
+
+            // Act
+            var endpointBuilder = builder.Map(RoutePatternFactory.Parse("/"), "Display name!", Handle);
+
+            // Assert
+            var endpointBuilder1 = GetRouteEndpointBuilder(builder);
+            Assert.Equal("Display name!", endpointBuilder1.DisplayName);
+            Assert.Equal("/", endpointBuilder1.RoutePattern.RawText);
+            Assert.Equal(2, endpointBuilder1.Metadata.Count);
+            Assert.IsType<Attribute1>(endpointBuilder1.Metadata[0]);
+            Assert.IsType<Attribute2>(endpointBuilder1.Metadata[1]);
+        }
+
+        [Fact]
+        public void MapEndpoint_ExplicitMetadataAddedAfterAttributeMetadata()
+        {
+            // Arrange
+            var builder = new DefaultEndpointRouteBuilder();
+
+            // Act
+            var endpointBuilder = builder.Map(RoutePatternFactory.Parse("/"), "Display name!", Handle, new Metadata());
+
+            // Assert
+            var endpointBuilder1 = GetRouteEndpointBuilder(builder);
+            Assert.Equal("Display name!", endpointBuilder1.DisplayName);
+            Assert.Equal("/", endpointBuilder1.RoutePattern.RawText);
+            Assert.Equal(3, endpointBuilder1.Metadata.Count);
+            Assert.IsType<Attribute1>(endpointBuilder1.Metadata[0]);
+            Assert.IsType<Attribute2>(endpointBuilder1.Metadata[1]);
+            Assert.IsType<Metadata>(endpointBuilder1.Metadata[2]);
+        }
+
+        [Attribute1]
+        [Attribute2]
+        private static Task Handle(HttpContext context) => Task.CompletedTask;
+
+        private class Attribute1 : Attribute
+        {
+        }
+
+        private class Attribute2 : Attribute
+        {
+        }
+
+        private class Metadata
+        {
+
+        }
     }
 }

src/Http/Routing/test/testassets/RoutingSandbox/UseEndpointRoutingStartup.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.IO;
 using System.Linq;
 using System.Text;
@@ -46,6 +47,10 @@ namespace RoutingSandbox
                         foreach (var endpoint in dataSource.Endpoints.OfType<RouteEndpoint>().OrderBy(e => e.RoutePattern.RawText, StringComparer.OrdinalIgnoreCase))
                         {
                             sb.AppendLine($"- {endpoint.RoutePattern.RawText}");
+                            foreach (var metadata in endpoint.Metadata)
+                            {
+                                sb.AppendLine("    " + metadata);
+                            }
                         }
 
                         var response = httpContext.Response;
@@ -79,6 +84,10 @@ namespace RoutingSandbox
                         return Task.CompletedTask;
                     });
 
+                builder.MapGet("/attributes", HandlerWithAttributes);
+
+                builder.Map("/getwithattributes", Handler);
+
                 builder.MapFramework(frameworkBuilder =>
                 {
                     frameworkBuilder.AddPattern("/transform/{hub:slugify=TestHub}/{method:slugify=TestMethod}");
@@ -92,5 +101,29 @@ namespace RoutingSandbox
 
             app.UseStaticFiles();
         }
+
+        [Authorize]
+        private Task HandlerWithAttributes(HttpContext context)
+        {
+            return context.Response.WriteAsync("I have ann authorize attribute");
+        }
+
+        [HttpGet]
+        private Task Handler(HttpContext context)
+        {
+            return context.Response.WriteAsync("I have a method metadata attribute");
+        }
+
+        private class AuthorizeAttribute : Attribute
+        {
+
+        }
+
+        private class HttpGetAttribute : Attribute, IHttpMethodMetadata
+        {
+            public bool AcceptCorsPreflight => false;
+
+            public IReadOnlyList<string> HttpMethods { get; } = new List<string> { "GET" };
+        }
     }
 }