Update FilterCollectionExtensions (#359)

* update

* update

* update

* update AddForFeature

* add test

* update

Author: zhiyuanliang-ms

src/Microsoft.FeatureManagement.AspNetCore/FeatureGatedAsyncActionFilter.cs

@@ -4,33 +4,73 @@
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.Extensions.DependencyInjection;
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 
 namespace Microsoft.FeatureManagement
 {
     /// <summary>
-    /// A place holder MVC filter that is used to dynamically activate a filter based on whether a feature is enabled.
+    /// A place holder MVC filter that is used to dynamically activate a filter based on whether a feature (or set of features) is enabled.
     /// </summary>
     /// <typeparam name="T">The filter that will be used instead of this placeholder.</typeparam>
     class FeatureGatedAsyncActionFilter<T> : IAsyncActionFilter where T : IAsyncActionFilter
     {
-        public FeatureGatedAsyncActionFilter(string featureName)
+        /// <summary>
+        /// Creates a feature gated filter for multiple features with a specified requirement type and ability to negate the evaluation.
+        /// </summary>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled.</param>
+        /// <param name="negate">Whether to negate the evaluation result.</param>
+        /// <param name="features">The features that control whether the wrapped filter executes.</param>
+        public FeatureGatedAsyncActionFilter(RequirementType requirementType, bool negate, params string[] features)
         {
-            if (string.IsNullOrEmpty(featureName))
+            if (features == null || features.Length == 0)
             {
-                throw new ArgumentNullException(nameof(featureName));
+                throw new ArgumentNullException(nameof(features));
             }
 
-            FeatureName = featureName;
+            Features = features;
+            RequirementType = requirementType;
+            Negate = negate;
         }
 
-        public string FeatureName { get; }
+        /// <summary>
+        /// The set of features that gate the wrapped filter.
+        /// </summary>
+        public IEnumerable<string> Features { get; }
+
+        /// <summary>
+        /// Controls whether any or all features in <see cref="Features"/> should be enabled to allow the wrapped filter to execute.
+        /// </summary>
+        public RequirementType RequirementType { get; }
+
+        /// <summary>
+        /// Negates the evaluation for whether or not the wrapped filter should execute.
+        /// </summary>
+        public bool Negate { get; }
 
         public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
         {
-            IFeatureManager featureManager = context.HttpContext.RequestServices.GetRequiredService<IFeatureManagerSnapshot>();
+            IFeatureManagerSnapshot featureManager = context.HttpContext.RequestServices.GetRequiredService<IFeatureManagerSnapshot>();
+
+            bool enabled;
+
+            // Enabled state is determined by either 'any' or 'all' features being enabled.
+            if (RequirementType == RequirementType.All)
+            {
+                enabled = await Features.All(async f => await featureManager.IsEnabledAsync(f).ConfigureAwait(false));
+            }
+            else
+            {
+                enabled = await Features.Any(async f => await featureManager.IsEnabledAsync(f).ConfigureAwait(false));
+            }
+
+            if (Negate)
+            {
+                enabled = !enabled;
+            }
 
-            if (await featureManager.IsEnabledAsync(FeatureName).ConfigureAwait(false))
+            if (enabled)
             {
                 IAsyncActionFilter filter = ActivatorUtilities.CreateInstance<T>(context.HttpContext.RequestServices);
 

src/Microsoft.FeatureManagement.AspNetCore/FilterCollectionExtensions.cs

@@ -16,12 +16,63 @@ public static class FilterCollectionExtensions
         /// <typeparam name="TFilterType">The MVC filter to add and use if the feature is enabled.</typeparam>
         /// <param name="filters">The filter collection to add to.</param>
         /// <param name="feature">The feature that will need to enabled to trigger the execution of the MVC filter.</param>
-        /// <returns></returns>
+        /// <returns>The reference to the added filter metadata.</returns>
         public static IFilterMetadata AddForFeature<TFilterType>(this FilterCollection filters, string feature) where TFilterType : IAsyncActionFilter
         {
-            IFilterMetadata filterMetadata = null;
+            IFilterMetadata filterMetadata = new FeatureGatedAsyncActionFilter<TFilterType>(RequirementType.Any, false, feature);
 
-            filters.Add(new FeatureGatedAsyncActionFilter<TFilterType>(feature));
+            filters.Add(filterMetadata);
+
+            return filterMetadata;
+        }
+
+        /// <summary>
+        /// Adds an MVC filter that will only activate during a request if the specified feature is enabled.
+        /// </summary>
+        /// <typeparam name="TFilterType">The MVC filter to add and use if the feature is enabled.</typeparam>
+        /// <param name="filters">The filter collection to add to.</param>
+        /// <param name="features">The features that control whether the MVC filter executes.</param>
+        /// <returns>The reference to the added filter metadata.</returns>
+        public static IFilterMetadata AddForFeature<TFilterType>(this FilterCollection filters, params string[] features) where TFilterType : IAsyncActionFilter
+        {
+            IFilterMetadata filterMetadata = new FeatureGatedAsyncActionFilter<TFilterType>(RequirementType.Any, false, features);
+
+            filters.Add(filterMetadata);
+
+            return filterMetadata;
+        }
+
+        /// <summary>
+        /// Adds an MVC filter that will only activate during a request if the specified features are enabled based on the provided requirement type.
+        /// </summary>
+        /// <typeparam name="TFilterType">The MVC filter to add and use if the features condition is satisfied.</typeparam>
+        /// <param name="filters">The filter collection to add to.</param>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled.</param>
+        /// <param name="features">The features that control whether the MVC filter executes.</param>
+        /// <returns>The reference to the added filter metadata.</returns>
+        public static IFilterMetadata AddForFeature<TFilterType>(this FilterCollection filters, RequirementType requirementType, params string[] features) where TFilterType : IAsyncActionFilter
+        {
+            IFilterMetadata filterMetadata = new FeatureGatedAsyncActionFilter<TFilterType>(requirementType, false, features);
+
+            filters.Add(filterMetadata);
+
+            return filterMetadata;
+        }
+
+        /// <summary>
+        /// Adds an MVC filter that will only activate during a request if the specified features are enabled based on the provided requirement type and negation flag.
+        /// </summary>
+        /// <typeparam name="TFilterType">The MVC filter to add and use if the features condition is satisfied.</typeparam>
+        /// <param name="filters">The filter collection to add to.</param>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled.</param>
+        /// <param name="negate">Whether to negate the evaluation result for the provided features set.</param>
+        /// <param name="features">The features that control whether the MVC filter executes.</param>
+        /// <returns>The reference to the added filter metadata.</returns>
+        public static IFilterMetadata AddForFeature<TFilterType>(this FilterCollection filters, RequirementType requirementType, bool negate, params string[] features) where TFilterType : IAsyncActionFilter
+        {
+            IFilterMetadata filterMetadata = new FeatureGatedAsyncActionFilter<TFilterType>(requirementType, negate, features);
+
+            filters.Add(filterMetadata);
 
             return filterMetadata;
         }

tests/Tests.FeatureManagement.AspNetCore/FeatureManagementAspNetCore.cs

@@ -202,6 +202,47 @@ public async Task GatesRazorPageFeatures()
             Assert.Equal(HttpStatusCode.OK, gateAnyNegateResponse.StatusCode);
         }
 
+        [Fact]
+        public async Task GatesActionFilterFeatures()
+        {
+            IConfiguration config = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();
+
+            TestServer server = new TestServer(WebHost.CreateDefaultBuilder().ConfigureServices(services =>
+            {
+                services
+                    .AddSingleton(config)
+                    .AddFeatureManagement()
+                    .AddFeatureFilter<TestFilter>();
+
+                services.AddMvcCore(o =>
+                {
+                    DisableEndpointRouting(o);
+                    o.Filters.AddForFeature<MvcFilter>(RequirementType.All, Features.ConditionalFeature, Features.ConditionalFeature2);
+                });
+            }).Configure(app => app.UseMvc()));
+
+            TestFilter filter = (TestFilter)server.Host.Services.GetRequiredService<IEnumerable<IFeatureFilterMetadata>>().First(f => f is TestFilter);
+            HttpClient client = server.CreateClient();
+
+            //
+            // Enable all features
+            filter.Callback = _ => Task.FromResult(true);
+            HttpResponseMessage res = await client.GetAsync("");
+            Assert.True(res.Headers.Contains(nameof(MvcFilter)));
+
+            //
+            // Enable 1/2 features
+            filter.Callback = ctx => Task.FromResult(ctx.FeatureName == Features.ConditionalFeature);
+            res = await client.GetAsync("");
+            Assert.False(res.Headers.Contains(nameof(MvcFilter)));
+
+            //
+            // Enable no
+            filter.Callback = _ => Task.FromResult(false);
+            res = await client.GetAsync("");
+            Assert.False(res.Headers.Contains(nameof(MvcFilter)));
+        }
+
         private static void DisableEndpointRouting(MvcOptions options)
         {
             options.EnableEndpointRouting = false;