Add AllowAnonymous extension method on IEndpointConventionBuilder (#21909)

src/Security/Authorization/Policy/ref/Microsoft.AspNetCore.Authorization.Policy.netcoreapp.cs

@@ -44,6 +44,7 @@ namespace Microsoft.AspNetCore.Builder
     }
     public static partial class AuthorizationEndpointConventionBuilderExtensions
     {
+        public static TBuilder AllowAnonymous<TBuilder>(this TBuilder builder) where TBuilder : Microsoft.AspNetCore.Builder.IEndpointConventionBuilder { throw null; }
         public static TBuilder RequireAuthorization<TBuilder>(this TBuilder builder) where TBuilder : Microsoft.AspNetCore.Builder.IEndpointConventionBuilder { throw null; }
         public static TBuilder RequireAuthorization<TBuilder>(this TBuilder builder, params Microsoft.AspNetCore.Authorization.IAuthorizeData[] authorizeData) where TBuilder : Microsoft.AspNetCore.Builder.IEndpointConventionBuilder { throw null; }
         public static TBuilder RequireAuthorization<TBuilder>(this TBuilder builder, params string[] policyNames) where TBuilder : Microsoft.AspNetCore.Builder.IEndpointConventionBuilder { throw null; }

src/Security/Authorization/Policy/src/AuthorizationEndpointConventionBuilderExtensions.cs

@@ -13,6 +13,9 @@ namespace Microsoft.AspNetCore.Builder
     /// </summary>
     public static class AuthorizationEndpointConventionBuilderExtensions
     {
+
+        private static readonly IAllowAnonymous _allowAnonymousMetadata = new AllowAnonymousAttribute();
+
         /// <summary>
         /// Adds the default authorization policy to the endpoint(s).
         /// </summary>
@@ -79,6 +82,22 @@ namespace Microsoft.AspNetCore.Builder
             return builder;
         }
 
+        /// <summary>
+        /// Allows anonymous access to the endpoint by adding <see cref="AllowAnonymousAttribute" /> to the endpoint metadata. This will bypass
+        /// all authorization checks for the endpoint including the default authorization policy and fallback authorization policy.
+        /// </summary>
+        /// <param name="builder">The endpoint convention builder.</param>
+        /// <returns>The original convention builder parameter.</returns>
+        public static TBuilder AllowAnonymous<TBuilder>(this TBuilder builder) where TBuilder : IEndpointConventionBuilder
+        {
+            builder.Add(endpointBuilder =>
+            {
+                endpointBuilder.Metadata.Add(_allowAnonymousMetadata);
+            });
+            return builder;
+        }
+
+
         private static void RequireAuthorizationCore<TBuilder>(TBuilder builder, IEnumerable<IAuthorizeData> authorizeData)
             where TBuilder : IEndpointConventionBuilder
         {

src/Security/Authorization/test/AuthorizationEndpointConventionBuilderExtensionsTests.cs

@@ -121,6 +121,37 @@ namespace Microsoft.AspNetCore.Authorization.Test
             Assert.True(chainedBuilder.TestProperty);
         }
 
+        [Fact]
+        public void AllowAnonymous_Default()
+        {
+            // Arrange
+            var builder = new TestEndpointConventionBuilder();
+
+            // Act
+            builder.AllowAnonymous();
+
+            // Assert
+            var convention = Assert.Single(builder.Conventions);
+
+            var endpointModel = new RouteEndpointBuilder((context) => Task.CompletedTask, RoutePatternFactory.Parse("/"), 0);
+            convention(endpointModel);
+
+            Assert.IsAssignableFrom<IAllowAnonymous>(Assert.Single(endpointModel.Metadata));
+        }
+
+        [Fact]
+        public void AllowAnonymous_ChainedCall()
+        {
+            // Arrange
+            var builder = new TestEndpointConventionBuilder();
+
+            // Act
+            var chainedBuilder = builder.AllowAnonymous();
+
+            // Assert
+            Assert.True(chainedBuilder.TestProperty);
+        }
+
         private class TestEndpointConventionBuilder : IEndpointConventionBuilder
         {
             public IList<Action<EndpointBuilder>> Conventions { get; } = new List<Action<EndpointBuilder>>();