Add support for route handler filter factories (#40667)

* Add support for route handler filter factories

* Address feedback from peer review

* Apply suggestions from code review

Co-authored-by: David Fowler <[email protected]>

* Fix XML comment for RouteHandlerFilterDelegate

* React to feedback from API review

* Fix up RouteHandlerContext instantiation

* Address more feedback from peer review

* Remove RouteHandlerContext passing

* Remove old RouteHandlerFilterFactories implementation

* Fix up RouteHandlerContext references

Co-authored-by: David Fowler <[email protected]>

Author: captainsafia

src/Http/Http.Abstractions/src/IRouteHandlerFilter.cs

@@ -9,12 +9,12 @@ namespace Microsoft.AspNetCore.Http;
 public interface IRouteHandlerFilter
 {
     /// <summary>
-    /// Implements the core logic associated with the filter given a <see cref="RouteHandlerFilterContext"/>
+    /// Implements the core logic associated with the filter given a <see cref="RouteHandlerInvocationContext"/>
     /// and the next filter to call in the pipeline.
     /// </summary>
-    /// <param name="context">The <see cref="RouteHandlerFilterContext"/> associated with the current request/response.</param>
+    /// <param name="context">The <see cref="RouteHandlerInvocationContext"/> associated with the current request/response.</param>
     /// <param name="next">The next filter in the pipeline.</param>
     /// <returns>An awaitable result of calling the handler and apply
     /// any modifications made by filters in the pipeline.</returns>
-    ValueTask<object?> InvokeAsync(RouteHandlerFilterContext context, Func<RouteHandlerFilterContext, ValueTask<object?>> next);
+    ValueTask<object?> InvokeAsync(RouteHandlerInvocationContext context, RouteHandlerFilterDelegate next);
 }

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

@@ -1,18 +1,23 @@
 #nullable enable
 *REMOVED*abstract Microsoft.AspNetCore.Http.HttpResponse.ContentType.get -> string!
 Microsoft.AspNetCore.Http.EndpointMetadataCollection.GetRequiredMetadata<T>() -> T!
-Microsoft.AspNetCore.Http.RouteHandlerFilterContext.RouteHandlerFilterContext(Microsoft.AspNetCore.Http.HttpContext! httpContext, params object![]! parameters) -> void
-Microsoft.AspNetCore.Http.IRouteHandlerFilter.InvokeAsync(Microsoft.AspNetCore.Http.RouteHandlerFilterContext! context, System.Func<Microsoft.AspNetCore.Http.RouteHandlerFilterContext!, System.Threading.Tasks.ValueTask<object?>>! next) -> System.Threading.Tasks.ValueTask<object?>
+Microsoft.AspNetCore.Http.IRouteHandlerFilter.InvokeAsync(Microsoft.AspNetCore.Http.RouteHandlerInvocationContext! context, Microsoft.AspNetCore.Http.RouteHandlerFilterDelegate! next) -> System.Threading.Tasks.ValueTask<object?>
 Microsoft.AspNetCore.Http.Metadata.IFromFormMetadata
 Microsoft.AspNetCore.Http.Metadata.IFromFormMetadata.Name.get -> string?
+Microsoft.AspNetCore.Http.RouteHandlerContext
+Microsoft.AspNetCore.Http.RouteHandlerContext.EndpointMetadata.get -> Microsoft.AspNetCore.Http.EndpointMetadataCollection!
+Microsoft.AspNetCore.Http.RouteHandlerContext.MethodInfo.get -> System.Reflection.MethodInfo!
+Microsoft.AspNetCore.Http.RouteHandlerContext.RouteHandlerContext(System.Reflection.MethodInfo! methodInfo, Microsoft.AspNetCore.Http.EndpointMetadataCollection! endpointMetadata) -> void
+Microsoft.AspNetCore.Http.RouteHandlerFilterDelegate
+Microsoft.AspNetCore.Http.RouteHandlerInvocationContext
+Microsoft.AspNetCore.Http.RouteHandlerInvocationContext.HttpContext.get -> Microsoft.AspNetCore.Http.HttpContext!
+Microsoft.AspNetCore.Http.RouteHandlerInvocationContext.Parameters.get -> System.Collections.Generic.IList<object?>!
+Microsoft.AspNetCore.Http.RouteHandlerInvocationContext.RouteHandlerInvocationContext(Microsoft.AspNetCore.Http.HttpContext! httpContext, params object![]! parameters) -> void
 Microsoft.AspNetCore.Routing.RouteValueDictionary.RouteValueDictionary(Microsoft.AspNetCore.Routing.RouteValueDictionary? dictionary) -> void
 Microsoft.AspNetCore.Routing.RouteValueDictionary.RouteValueDictionary(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string!, object?>>? values) -> void
 Microsoft.AspNetCore.Routing.RouteValueDictionary.RouteValueDictionary(System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string!, string?>>? values) -> void
 abstract Microsoft.AspNetCore.Http.HttpResponse.ContentType.get -> string?
 Microsoft.AspNetCore.Http.Metadata.ISkipStatusCodePagesMetadata
-Microsoft.AspNetCore.Http.RouteHandlerFilterContext
-Microsoft.AspNetCore.Http.RouteHandlerFilterContext.HttpContext.get -> Microsoft.AspNetCore.Http.HttpContext!
-Microsoft.AspNetCore.Http.RouteHandlerFilterContext.Parameters.get -> System.Collections.Generic.IList<object?>!
 Microsoft.AspNetCore.Http.IRouteHandlerFilter
 Microsoft.AspNetCore.Http.Metadata.IEndpointDescriptionMetadata
 Microsoft.AspNetCore.Http.Metadata.IEndpointDescriptionMetadata.Description.get -> string!

src/Http/Http.Abstractions/src/RouteHandlerContext.cs

@@ -0,0 +1,34 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Reflection;
+
+namespace Microsoft.AspNetCore.Http;
+
+/// <summary>
+/// Represents the information accessible via the route handler filter
+/// API when the user is constructing a new route handler.
+/// </summary>
+public sealed class RouteHandlerContext
+{
+    /// <summary>
+    /// Creates a new instance of the <see cref="RouteHandlerContext"/>.
+    /// </summary>
+    /// <param name="methodInfo">The <see cref="MethodInfo"/> associated with the route handler of the current request.</param>
+    /// <param name="endpointMetadata">The <see cref="EndpointMetadataCollection"/> associated with the endpoint the filter is targeting.</param>
+    public RouteHandlerContext(MethodInfo methodInfo, EndpointMetadataCollection endpointMetadata)
+    {
+        MethodInfo = methodInfo;
+        EndpointMetadata = endpointMetadata;
+    }
+
+    /// <summary>
+    /// The <see cref="MethodInfo"/> associated with the current route handler.
+    /// </summary>
+    public MethodInfo MethodInfo { get; }
+
+    /// <summary>
+    /// The <see cref="EndpointMetadataCollection"/> associated with the current endpoint.
+    /// </summary>
+    public EndpointMetadataCollection EndpointMetadata { get; }
+}

src/Http/Http.Abstractions/src/RouteHandlerFilterDelegate.cs

@@ -0,0 +1,13 @@
+// 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;
+
+/// <summary>
+/// A delegate that is applied as a filter on a route handler.
+/// </summary>
+/// <param name="context">The <see cref="RouteHandlerInvocationContext"/> associated with the current request.</param>
+/// <returns>
+/// A <see cref="ValueTask"/> result of calling the handler and applying any modifications made by filters in the pipeline.
+/// </returns>
+public delegate ValueTask<object?> RouteHandlerFilterDelegate(RouteHandlerInvocationContext context);

src/Http/Http.Abstractions/src/RouteHandlerFilterContext.cs renamed to src/Http/Http.Abstractions/src/RouteHandlerInvocationContext.cs

@@ -7,14 +7,14 @@ namespace Microsoft.AspNetCore.Http;
 /// Provides an abstraction for wrapping the <see cref="HttpContext"/> and parameters
 /// provided to a route handler.
 /// </summary>
-public class RouteHandlerFilterContext
+public sealed class RouteHandlerInvocationContext
 {
     /// <summary>
-    /// Creates a new instance of the <see cref="RouteHandlerFilterContext"/> for a given request.
+    /// Creates a new instance of the <see cref="RouteHandlerInvocationContext"/> for a given request.
     /// </summary>
     /// <param name="httpContext">The <see cref="HttpContext"/> associated with the current request.</param>
     /// <param name="parameters">A list of parameters provided in the current request.</param>
-    public RouteHandlerFilterContext(HttpContext httpContext, params object[] parameters)
+    public RouteHandlerInvocationContext(HttpContext httpContext, params object[] parameters)
     {
         HttpContext = httpContext;
         Parameters = parameters;
@@ -28,7 +28,7 @@ public RouteHandlerFilterContext(HttpContext httpContext, params object[] parame
     /// <summary>
     /// A list of parameters provided in the current request to the filter.
     /// <remarks>
-    /// This list is not read-only to premit modifying of existing parameters by filters.
+    /// This list is not read-only to permit modifying of existing parameters by filters.
     /// </remarks>
     /// </summary>
     public IList<object?> Parameters { get; }

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

@@ -1,8 +1,8 @@
 #nullable enable
+Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions.RouteHandlerFilterFactories.get -> System.Collections.Generic.IReadOnlyList<System.Func<Microsoft.AspNetCore.Http.RouteHandlerContext!, Microsoft.AspNetCore.Http.RouteHandlerFilterDelegate!, Microsoft.AspNetCore.Http.RouteHandlerFilterDelegate!>!>?
+Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions.RouteHandlerFilterFactories.init -> void
 Microsoft.Extensions.DependencyInjection.RouteHandlerJsonServiceExtensions
 static Microsoft.Extensions.DependencyInjection.RouteHandlerJsonServiceExtensions.ConfigureRouteHandlerJsonOptions(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services, System.Action<Microsoft.AspNetCore.Http.Json.JsonOptions!>! configureOptions) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
-Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions.RouteHandlerFilters.get -> System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Http.IRouteHandlerFilter!>?
-Microsoft.AspNetCore.Http.RequestDelegateFactoryOptions.RouteHandlerFilters.init -> void
 Microsoft.AspNetCore.Http.EndpointDescriptionAttribute
 Microsoft.AspNetCore.Http.EndpointDescriptionAttribute.EndpointDescriptionAttribute(string! description) -> void
 Microsoft.AspNetCore.Http.EndpointDescriptionAttribute.Description.get -> string!

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

@@ -79,13 +79,13 @@ public static partial class RequestDelegateFactory
     private static readonly BinaryExpression TempSourceStringNullExpr = Expression.Equal(TempSourceStringExpr, Expression.Constant(null));
     private static readonly UnaryExpression TempSourceStringIsNotNullOrEmptyExpr = Expression.Not(Expression.Call(StringIsNullOrEmptyMethod, TempSourceStringExpr));
 
-    private static readonly ConstructorInfo RouteHandlerFilterContextConstructor = typeof(RouteHandlerFilterContext).GetConstructor(new[] { typeof(HttpContext), typeof(object[]) })!;
-    private static readonly ParameterExpression FilterContextExpr = Expression.Parameter(typeof(RouteHandlerFilterContext), "context");
-    private static readonly MemberExpression FilterContextParametersExpr = Expression.Property(FilterContextExpr, typeof(RouteHandlerFilterContext).GetProperty(nameof(RouteHandlerFilterContext.Parameters))!);
-    private static readonly MemberExpression FilterContextHttpContextExpr = Expression.Property(FilterContextExpr, typeof(RouteHandlerFilterContext).GetProperty(nameof(RouteHandlerFilterContext.HttpContext))!);
+    private static readonly ConstructorInfo RouteHandlerInvocationContextConstructor = typeof(RouteHandlerInvocationContext).GetConstructor(new[] { typeof(HttpContext), typeof(object[]) })!;
+    private static readonly ParameterExpression FilterContextExpr = Expression.Parameter(typeof(RouteHandlerInvocationContext), "context");
+    private static readonly MemberExpression FilterContextParametersExpr = Expression.Property(FilterContextExpr, typeof(RouteHandlerInvocationContext).GetProperty(nameof(RouteHandlerInvocationContext.Parameters))!);
+    private static readonly MemberExpression FilterContextHttpContextExpr = Expression.Property(FilterContextExpr, typeof(RouteHandlerInvocationContext).GetProperty(nameof(RouteHandlerInvocationContext.HttpContext))!);
     private static readonly MemberExpression FilterContextHttpContextResponseExpr = Expression.Property(FilterContextHttpContextExpr, typeof(HttpContext).GetProperty(nameof(HttpContext.Response))!);
     private static readonly MemberExpression FilterContextHttpContextStatusCodeExpr = Expression.Property(FilterContextHttpContextResponseExpr, typeof(HttpResponse).GetProperty(nameof(HttpResponse.StatusCode))!);
-    private static readonly ParameterExpression InvokedFilterContextExpr = Expression.Parameter(typeof(RouteHandlerFilterContext), "filterContext");
+    private static readonly ParameterExpression InvokedFilterContextExpr = Expression.Parameter(typeof(RouteHandlerInvocationContext), "filterContext");
 
     private static readonly string[] DefaultAcceptsContentType = new[] { "application/json" };
     private static readonly string[] FormFileContentType = new[] { "multipart/form-data" };
@@ -166,7 +166,7 @@ private static FactoryContext CreateFactoryContext(RequestDelegateFactoryOptions
             RouteParameters = options?.RouteParameterNames?.ToList(),
             ThrowOnBadRequest = options?.ThrowOnBadRequest ?? false,
             DisableInferredFromBody = options?.DisableInferBodyFromParameters ?? false,
-            Filters = options?.RouteHandlerFilters?.ToList()
+            Filters = options?.RouteHandlerFilterFactories?.ToList()
         };
 
     private static Func<object?, HttpContext, Task> CreateTargetableRequestDelegate(MethodInfo methodInfo, Expression? targetExpression, FactoryContext factoryContext)
@@ -196,15 +196,15 @@ private static FactoryContext CreateFactoryContext(RequestDelegateFactoryOptions
         if (factoryContext.Filters is { Count: > 0 })
         {
             var filterPipeline = CreateFilterPipeline(methodInfo, targetExpression, factoryContext);
-            Expression<Func<RouteHandlerFilterContext, ValueTask<object?>>> invokePipeline = (context) => filterPipeline(context);
+            Expression<Func<RouteHandlerInvocationContext, ValueTask<object?>>> invokePipeline = (context) => filterPipeline(context);
             returnType = typeof(ValueTask<object?>);
-            // var filterContext = new RouteHandlerFilterContext(httpContext, new[] { (object)name_local, (object)int_local });
+            // var filterContext = new RouteHandlerInvocationContext(httpContext, new[] { (object)name_local, (object)int_local });
             // invokePipeline.Invoke(filterContext);
             factoryContext.MethodCall = Expression.Block(
                 new[] { InvokedFilterContextExpr },
                 Expression.Assign(
                     InvokedFilterContextExpr,
-                    Expression.New(RouteHandlerFilterContextConstructor,
+                    Expression.New(RouteHandlerInvocationContextConstructor,
                         new Expression[] { HttpContextExpr, Expression.NewArrayInit(typeof(object), factoryContext.BoxedArgs) })),
                     Expression.Invoke(invokePipeline, InvokedFilterContextExpr)
                 );
@@ -222,13 +222,13 @@ private static FactoryContext CreateFactoryContext(RequestDelegateFactoryOptions
         return HandleRequestBodyAndCompileRequestDelegate(responseWritingMethodCall, factoryContext);
     }
 
-    private static Func<RouteHandlerFilterContext, ValueTask<object?>> CreateFilterPipeline(MethodInfo methodInfo, Expression? target, FactoryContext factoryContext)
+    private static RouteHandlerFilterDelegate CreateFilterPipeline(MethodInfo methodInfo, Expression? target, FactoryContext factoryContext)
     {
         Debug.Assert(factoryContext.Filters is not null);
         // httpContext.Response.StatusCode >= 400
         // ? Task.CompletedTask
         // : handler((string)context.Parameters[0], (int)context.Parameters[1])
-        var filteredInvocation = Expression.Lambda<Func<RouteHandlerFilterContext, ValueTask<object?>>>(
+        var filteredInvocation = Expression.Lambda<RouteHandlerFilterDelegate>(
             Expression.Condition(
                 Expression.GreaterThanOrEqual(FilterContextHttpContextStatusCodeExpr, Expression.Constant(400)),
                 CompletedValueTaskExpr,
@@ -240,12 +240,16 @@ target is null
                             : Expression.Call(target, methodInfo, factoryContext.ContextArgAccess))
                 )),
             FilterContextExpr).Compile();
+        var routeHandlerContext = new RouteHandlerContext(
+            methodInfo,
+            new EndpointMetadataCollection(factoryContext.Metadata));
 
         for (var i = factoryContext.Filters.Count - 1; i >= 0; i--)
         {
-            var currentFilter = factoryContext.Filters![i];
+            var currentFilterFactory = factoryContext.Filters[i];
             var nextFilter = filteredInvocation;
-            filteredInvocation = (RouteHandlerFilterContext context) => currentFilter.InvokeAsync(context, nextFilter);
+            var currentFilter = currentFilterFactory(routeHandlerContext, nextFilter);
+            filteredInvocation = (RouteHandlerInvocationContext context) => currentFilter(context);
 
         }
         return filteredInvocation;
@@ -264,7 +268,7 @@ private static Expression[] CreateArguments(ParameterInfo[]? parameters, Factory
         {
             args[i] = CreateArgument(parameters[i], factoryContext);
             // Register expressions containing the boxed and unboxed variants
-            // of the route handler's arguments for use in RouteHandlerFilterContext
+            // of the route handler's arguments for use in RouteHandlerInvocationContext
             // construction and route handler invocation.
             // (string)context.Parameters[0];
             factoryContext.ContextArgAccess.Add(
@@ -1693,7 +1697,7 @@ private class FactoryContext
         public List<Expression> ContextArgAccess { get; } = new();
         public Expression? MethodCall { get; set; }
         public List<Expression> BoxedArgs { get; } = new();
-        public List<IRouteHandlerFilter>? Filters { get; init; }
+        public List<Func<RouteHandlerContext, RouteHandlerFilterDelegate, RouteHandlerFilterDelegate>>? Filters { get; init; }
     }
 
     private static class RequestDelegateFactoryConstants

src/Http/Http.Extensions/src/RequestDelegateFactoryOptions.cs

@@ -35,5 +35,5 @@ public sealed class RequestDelegateFactoryOptions
     /// <summary>
     /// The list of filters that must run in the pipeline for a given route handler.
     /// </summary>
-    public IReadOnlyList<IRouteHandlerFilter>? RouteHandlerFilters { get; init; }
+    public IReadOnlyList<Func<RouteHandlerContext, RouteHandlerFilterDelegate, RouteHandlerFilterDelegate>>? RouteHandlerFilterFactories { get; init; }
 }