Improve Minimal APIs support for request media types #35082

src/Http/Http.Abstractions/src/Metadata/IAcceptsMetadata.cs

@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Http.Metadata
+{
+    /// <summary>
+    /// Interface for accepting request media types.
+    /// </summary>
+    public interface IAcceptsMetadata
+    {
+        /// <summary>
+        /// Gets a list of the allowed request content types.
+        /// If the incoming request does not have a <c>Content-Type</c> with one of these values, the request will be rejected with a 415 response.
+        /// </summary>
+        IReadOnlyList<string> ContentTypes { get; }
+
+        /// <summary>
+        /// Gets the type being read from the request. 
+        /// </summary>
+        Type? RequestType { get; }
+    }
+}

src/Http/Http.Abstractions/src/PublicAPI.Unshipped.txt

@@ -7,6 +7,9 @@
 *REMOVED*abstract Microsoft.AspNetCore.Http.HttpRequest.ContentType.get -> string!
 Microsoft.AspNetCore.Http.IResult
 Microsoft.AspNetCore.Http.IResult.ExecuteAsync(Microsoft.AspNetCore.Http.HttpContext! httpContext) -> System.Threading.Tasks.Task!
+Microsoft.AspNetCore.Http.Metadata.IAcceptsMetadata
+Microsoft.AspNetCore.Http.Metadata.IAcceptsMetadata.ContentTypes.get -> System.Collections.Generic.IReadOnlyList<string!>!
+Microsoft.AspNetCore.Http.Metadata.IAcceptsMetadata.RequestType.get -> System.Type?
 Microsoft.AspNetCore.Http.Metadata.IFromBodyMetadata
 Microsoft.AspNetCore.Http.Metadata.IFromBodyMetadata.AllowEmpty.get -> bool
 Microsoft.AspNetCore.Http.Metadata.IFromHeaderMetadata
@@ -18,6 +21,10 @@ Microsoft.AspNetCore.Http.Metadata.IFromRouteMetadata.Name.get -> string?
 Microsoft.AspNetCore.Http.Metadata.IFromServiceMetadata
 Microsoft.AspNetCore.Http.Endpoint.Endpoint(Microsoft.AspNetCore.Http.RequestDelegate? requestDelegate, Microsoft.AspNetCore.Http.EndpointMetadataCollection? metadata, string? displayName) -> void
 Microsoft.AspNetCore.Http.Endpoint.RequestDelegate.get -> Microsoft.AspNetCore.Http.RequestDelegate?
+Microsoft.AspNetCore.Http.RequestDelegateResult
+Microsoft.AspNetCore.Http.RequestDelegateResult.EndpointMetadata.get -> System.Collections.Generic.IReadOnlyList<object!>!
+Microsoft.AspNetCore.Http.RequestDelegateResult.RequestDelegate.get -> Microsoft.AspNetCore.Http.RequestDelegate!
+Microsoft.AspNetCore.Http.RequestDelegateResult.RequestDelegateResult(Microsoft.AspNetCore.Http.RequestDelegate! requestDelegate, System.Collections.Generic.IReadOnlyList<object!>! metadata) -> void
 Microsoft.AspNetCore.Routing.RouteValueDictionary.TryAdd(string! key, object? value) -> bool
 static readonly Microsoft.AspNetCore.Http.HttpProtocol.Http09 -> string!
 static Microsoft.AspNetCore.Http.HttpProtocol.IsHttp09(string! protocol) -> bool

src/Http/Http.Abstractions/src/RequestDelegateResult.cs

@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Http
+{
+    /// <summary>
+    /// The result of creating a <see cref="RequestDelegate" /> from a <see cref="Delegate" />
+    /// </summary>
+    public sealed class RequestDelegateResult
+    {
+        /// <summary>
+        /// Creates a new instance of <see cref="RequestDelegateResult"/>.
+        /// </summary>
+        public RequestDelegateResult(RequestDelegate requestDelegate, IReadOnlyList<object> metadata)
+        {
+            RequestDelegate = requestDelegate;
+            EndpointMetadata = metadata;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="RequestDelegate" />
+        /// </summary>
+        public RequestDelegate RequestDelegate { get;}
+
+        /// <summary>
+        /// Gets endpoint metadata inferred from creating the <see cref="RequestDelegate" />
+        /// </summary>
+        public IReadOnlyList<object> EndpointMetadata { get;}
+    }
+
+}

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

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>ASP.NET Core common extension methods for HTTP abstractions, HTTP headers, HTTP request/response, and session state.</Description>
@@ -16,6 +16,7 @@
     <Compile Include="..\..\Shared\StreamCopyOperationInternal.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)ProblemDetailsJsonConverter.cs" LinkBase="Shared"/>
     <Compile Include="$(SharedSourceRoot)HttpValidationProblemDetailsJsonConverter.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)RoutingMetadata\AcceptsMetadata.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Http/Http.Extensions/src/PublicAPI.Unshipped.txt

@@ -192,8 +192,8 @@ static Microsoft.AspNetCore.Http.HeaderDictionaryTypeExtensions.AppendList<T>(th
 static Microsoft.AspNetCore.Http.HeaderDictionaryTypeExtensions.GetTypedHeaders(this Microsoft.AspNetCore.Http.HttpRequest! request) -> Microsoft.AspNetCore.Http.Headers.RequestHeaders!
 static Microsoft.AspNetCore.Http.HeaderDictionaryTypeExtensions.GetTypedHeaders(this Microsoft.AspNetCore.Http.HttpResponse! response) -> Microsoft.AspNetCore.Http.Headers.ResponseHeaders!
 static Microsoft.AspNetCore.Http.HttpContextServerVariableExtensions.GetServerVariable(this Microsoft.AspNetCore.Http.HttpContext! context, string! variableName) -> string?
-static Microsoft.AspNetCore.Http.RequestDelegateFactory.Create(System.Delegate! action, Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions? options = null) -> Microsoft.AspNetCore.Http.RequestDelegate!
-static Microsoft.AspNetCore.Http.RequestDelegateFactory.Create(System.Reflection.MethodInfo! methodInfo, System.Func<Microsoft.AspNetCore.Http.HttpContext!, object!>? targetFactory = null, Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions? options = null) -> Microsoft.AspNetCore.Http.RequestDelegate!
+static Microsoft.AspNetCore.Http.RequestDelegateFactory.Create(System.Delegate! action, Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions? options = null) -> Microsoft.AspNetCore.Http.RequestDelegateResult!
+static Microsoft.AspNetCore.Http.RequestDelegateFactory.Create(System.Reflection.MethodInfo! methodInfo, System.Func<Microsoft.AspNetCore.Http.HttpContext!, object!>? targetFactory = null, Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions? options = null) -> Microsoft.AspNetCore.Http.RequestDelegateResult!
 static Microsoft.AspNetCore.Http.ResponseExtensions.Clear(this Microsoft.AspNetCore.Http.HttpResponse! response) -> void
 static Microsoft.AspNetCore.Http.ResponseExtensions.Redirect(this Microsoft.AspNetCore.Http.HttpResponse! response, string! location, bool permanent, bool preserveMethod) -> void
 static Microsoft.AspNetCore.Http.SendFileResponseExtensions.SendFileAsync(this Microsoft.AspNetCore.Http.HttpResponse! response, Microsoft.Extensions.FileProviders.IFileInfo! file, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task!

src/Http/Http.Extensions/src/RequestDelegateFactory.cs

@@ -4,6 +4,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Linq.Expressions;
+using System.Net.Http;
 using System.Reflection;
 using System.Security.Claims;
 using System.Text;
@@ -63,14 +64,16 @@ public static partial class RequestDelegateFactory
         private static readonly BinaryExpression TempSourceStringNotNullExpr = Expression.NotEqual(TempSourceStringExpr, Expression.Constant(null));
         private static readonly BinaryExpression TempSourceStringNullExpr = Expression.Equal(TempSourceStringExpr, Expression.Constant(null));
 
+        private static readonly AcceptsMetadata DefaultAcceptsMetadata = new(new[] { "application/json" });
+
         /// <summary>
         /// Creates a <see cref="RequestDelegate"/> implementation for <paramref name="action"/>.
         /// </summary>
         /// <param name="action">A request handler with any number of custom parameters that often produces a response with its return value.</param>
         /// <param name="options">The <see cref="RequestDelegateFactoryOptions"/> used to configure the behavior of the handler.</param>
-        /// <returns>The <see cref="RequestDelegate"/>.</returns>
+        /// <returns>The <see cref="RequestDelegateResult"/>.</returns>
 #pragma warning disable RS0026 // Do not add multiple public overloads with optional parameters
-        public static RequestDelegate Create(Delegate action, RequestDelegateFactoryOptions? options = null)
+        public static RequestDelegateResult Create(Delegate action, RequestDelegateFactoryOptions? options = null)
 #pragma warning restore RS0026 // Do not add multiple public overloads with optional parameters
         {
             if (action is null)
@@ -84,12 +87,15 @@ public static RequestDelegate Create(Delegate action, RequestDelegateFactoryOpti
                 null => null,
             };
 
-            var targetableRequestDelegate = CreateTargetableRequestDelegate(action.Method, options, targetExpression);
-
-            return httpContext =>
+            var factoryContext = new FactoryContext
             {
-                return targetableRequestDelegate(action.Target, httpContext);
+                ServiceProviderIsService = options?.ServiceProvider?.GetService<IServiceProviderIsService>()
             };
+
+            var targetableRequestDelegate = CreateTargetableRequestDelegate(action.Method, options, factoryContext, targetExpression);
+
+            return new RequestDelegateResult(httpContext => targetableRequestDelegate(action.Target, httpContext), factoryContext.Metadata);
+
         }
 
         /// <summary>
@@ -100,7 +106,7 @@ public static RequestDelegate Create(Delegate action, RequestDelegateFactoryOpti
         /// <param name="options">The <see cref="RequestDelegateFactoryOptions"/> used to configure the behavior of the handler.</param>
         /// <returns>The <see cref="RequestDelegate"/>.</returns>
 #pragma warning disable RS0026 // Do not add multiple public overloads with optional parameters
-        public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, object>? targetFactory = null, RequestDelegateFactoryOptions? options = null)
+        public static RequestDelegateResult Create(MethodInfo methodInfo, Func<HttpContext, object>? targetFactory = null, RequestDelegateFactoryOptions? options = null)
 #pragma warning restore RS0026 // Do not add multiple public overloads with optional parameters
         {
             if (methodInfo is null)
@@ -113,31 +119,30 @@ public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, ob
                 throw new ArgumentException($"{nameof(methodInfo)} does not have a declaring type.");
             }
 
+            var factoryContext = new FactoryContext
+            {
+                ServiceProviderIsService = options?.ServiceProvider?.GetService<IServiceProviderIsService>()
+            };
+
             if (targetFactory is null)
             {
                 if (methodInfo.IsStatic)
                 {
-                    var untargetableRequestDelegate = CreateTargetableRequestDelegate(methodInfo, options, targetExpression: null);
+                    var untargetableRequestDelegate = CreateTargetableRequestDelegate(methodInfo, options, factoryContext, targetExpression: null);
 
-                    return httpContext =>
-                    {
-                        return untargetableRequestDelegate(null, httpContext);
-                    };
+                    return new RequestDelegateResult(httpContext => untargetableRequestDelegate(null, httpContext), factoryContext.Metadata);
                 }
 
                 targetFactory = context => Activator.CreateInstance(methodInfo.DeclaringType)!;
             }
 
             var targetExpression = Expression.Convert(TargetExpr, methodInfo.DeclaringType);
-            var targetableRequestDelegate = CreateTargetableRequestDelegate(methodInfo, options, targetExpression);
+            var targetableRequestDelegate = CreateTargetableRequestDelegate(methodInfo, options, factoryContext, targetExpression);
 
-            return httpContext =>
-            {
-                return targetableRequestDelegate(targetFactory(httpContext), httpContext);
-            };
+            return new RequestDelegateResult(httpContext => targetableRequestDelegate(targetFactory(httpContext), httpContext), factoryContext.Metadata);
         }
 
-        private static Func<object?, HttpContext, Task> CreateTargetableRequestDelegate(MethodInfo methodInfo, RequestDelegateFactoryOptions? options, Expression? targetExpression)
+        private static Func<object?, HttpContext, Task> CreateTargetableRequestDelegate(MethodInfo methodInfo, RequestDelegateFactoryOptions? options, FactoryContext factoryContext, Expression? targetExpression)
         {
             // Non void return type
 
@@ -155,11 +160,6 @@ public static RequestDelegate Create(MethodInfo methodInfo, Func<HttpContext, ob
             //     return default;
             // }
 
-            var factoryContext = new FactoryContext()
-            {
-                ServiceProviderIsService = options?.ServiceProvider?.GetService<IServiceProviderIsService>()
-            };
-
             if (options?.RouteParameterNames is { } routeParameterNames)
             {
                 factoryContext.RouteParameters = new(routeParameterNames);
@@ -861,6 +861,7 @@ private static Expression BindParameterFromBody(ParameterInfo parameter, bool al
                 }
             }
 
+            factoryContext.Metadata.Add(DefaultAcceptsMetadata);
             var isOptional = IsOptionalParameter(parameter);
 
             factoryContext.JsonRequestBodyType = parameter.ParameterType;
@@ -1111,6 +1112,8 @@ private class FactoryContext
 
             public Dictionary<string, string> TrackedParameters { get; } = new();
             public bool HasMultipleBodyParameters { get; set; }
+
+            public List<object> Metadata { get; } = new();
         }
 
         private static class RequestDelegateFactoryConstants