Merge pull request #524 from crodriguesbr/add-feature-flags-endpoint-support

Add feature flags endpoint support

Author: jimmyca15

src/Microsoft.FeatureManagement.AspNetCore/FeatureGateEndpointFilter.cs

@@ -0,0 +1,98 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.HttpResults;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Microsoft.FeatureManagement.AspNetCore
+{
+    /// <summary>
+    /// An endpoint filter that controls access based on feature flag states.
+    /// </summary>
+    internal sealed class FeatureGateEndpointFilter : IEndpointFilter
+    {
+        /// <summary>
+        /// Gets the collection of feature flags to evaluate.
+        /// </summary>
+        private readonly IEnumerable<string> _features;
+
+        /// <summary>
+        /// Gets the type of requirement (All or Any) for feature evaluation.
+        /// </summary>
+        private readonly RequirementType _requirementType;
+
+        /// <summary>
+        /// Gets whether the feature evaluation result should be negated.
+        /// </summary>
+        private readonly bool _negate;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FeatureGateEndpointFilter"/> class.
+        /// </summary>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <exception cref="ArgumentNullException">Thrown when features collection is null or empty.</exception>
+        public FeatureGateEndpointFilter(params string[] features)
+            : this(RequirementType.All, negate: false, features)
+        {
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="FeatureGateEndpointFilter"/> class.
+        /// </summary>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled in order to pass.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <exception cref="ArgumentNullException">Thrown when features collection is null or empty.</exception>
+        public FeatureGateEndpointFilter(RequirementType requirementType, params string[] features)
+            : this(requirementType, negate: false, features)
+        {
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="FeatureGateEndpointFilter"/> class.
+        /// </summary>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled in order to pass.</param>
+        /// <param name="negate">Specifies whether the feature evaluation result should be negated.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <exception cref="ArgumentNullException">Thrown when features collection is null or empty.</exception>
+        public FeatureGateEndpointFilter(RequirementType requirementType, bool negate, params string[] features)
+        {
+            if (features == null || features.Length == 0)
+            {
+                throw new ArgumentNullException(nameof(features));
+            }
+
+            _features = features;
+            _requirementType = requirementType;
+            _negate = negate;
+        }
+
+        /// <summary>
+        /// Invokes the feature flag filter to control endpoint access based on feature states.
+        /// </summary>
+        /// <param name="context">The endpoint filter invocation context.</param>
+        /// <param name="next">The delegate representing the next filter in the pipeline.</param>
+        /// <returns>
+        /// A <see cref="NotFound"/> result if access is denied, otherwise continues the pipeline.
+        /// </returns>
+        public async ValueTask<object> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
+        {
+            IVariantFeatureManager fm = context.HttpContext.RequestServices.GetRequiredService<IVariantFeatureManagerSnapshot>();
+
+            bool enabled = _requirementType == RequirementType.All
+                ? await _features.All(async feature => await fm.IsEnabledAsync(feature).ConfigureAwait(false))
+                : await _features.Any(async feature => await fm.IsEnabledAsync(feature).ConfigureAwait(false));
+
+            bool isAllowed = _negate ? !enabled : enabled;
+
+            return isAllowed
+                ? await next(context).ConfigureAwait(false)
+                : Results.NotFound();
+        }
+    }
+}

src/Microsoft.FeatureManagement.AspNetCore/FeatureGateEndpointFilterExtensions.cs

@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.FeatureManagement.AspNetCore
+{
+    /// <summary>
+    /// Extension methods that provide feature management integration for ASP.NET Core endpoint building.
+    /// </summary>
+    public static class FeatureGateEndpointFilterExtensions
+    {
+        /// <summary>
+        /// Adds a filter to the endpoint that gates access based on whether one or more features are enabled.
+        /// All features must be enabled for access to be granted.
+        /// </summary>
+        /// <param name="builder">The endpoint convention builder.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <returns>The endpoint convention builder for chaining.</returns>
+        public static IEndpointConventionBuilder WithFeatureGate(this IEndpointConventionBuilder builder, params string[] features)
+        {
+            return builder.AddEndpointFilter(new FeatureGateEndpointFilter(features));
+        }
+
+        /// <summary>
+        /// Adds a filter to the endpoint with specified requirement type for multiple features.
+        /// </summary>
+        /// <param name="builder">The endpoint convention builder.</param>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled in order to pass.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <returns>The endpoint convention builder for chaining.</returns>
+        public static IEndpointConventionBuilder WithFeatureGate(this IEndpointConventionBuilder builder, RequirementType requirementType, params string[] features)
+        {
+            return builder.AddEndpointFilter(new FeatureGateEndpointFilter(requirementType, features));
+        }
+
+        /// <summary>
+        /// Adds a filter to the endpoint with negation capability for multiple features.
+        /// </summary>
+        /// <param name="builder">The endpoint convention builder.</param>
+        /// <param name="negate">Specifies whether the feature evaluation result should be negated.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <returns>The endpoint convention builder for chaining.</returns>
+        public static IEndpointConventionBuilder WithFeatureGate(this IEndpointConventionBuilder builder, bool negate, params string[] features)
+        {
+            return builder.AddEndpointFilter(new FeatureGateEndpointFilter(RequirementType.All, negate, features));
+        }
+
+        /// <summary>
+        /// Adds a filter to the endpoint with full control over requirement type and negation.
+        /// </summary>
+        /// <param name="builder">The endpoint convention builder.</param>
+        /// <param name="requirementType">Specifies whether all or any of the provided features should be enabled in order to pass.</param>
+        /// <param name="negate">Specifies whether the feature evaluation result should be negated.</param>
+        /// <param name="features">The collection of feature flags to evaluate.</param>
+        /// <returns>The endpoint convention builder for chaining.</returns>
+        public static IEndpointConventionBuilder WithFeatureGate(this IEndpointConventionBuilder builder, RequirementType requirementType, bool negate, params string[] features)
+        {
+            return builder.AddEndpointFilter(new FeatureGateEndpointFilter(requirementType, negate, features));
+        }
+    }
+}