PR feedback

Author: JamesNK

src/Http/Routing/src/Builder/RoutingEndpointConventionBuilderExtensions.cs

@@ -6,8 +6,21 @@
 
 namespace Microsoft.AspNetCore.Builder
 {
+    /// <summary>
+    /// Extension methods for adding routing metadata to endpoint instances using <see cref="IEndpointConventionBuilder"/>.
+    /// </summary>
     public static class RoutingEndpointConventionBuilderExtensions
     {
+        /// <summary>
+        /// Requires that endpoints match one of the specified hosts during routing.
+        /// </summary>
+        /// <param name="builder">The <see cref="IEndpointConventionBuilder"/> to add the metadata to.</param>
+        /// <param name="hosts">
+        /// The hosts used during routing.
+        /// Hosts should be Unicode rather than punycode, and may have a port.
+        /// An empty collection means any host will be accepted.
+        /// </param>
+        /// <returns>A reference to this instance after the operation has completed.</returns>
         public static IEndpointConventionBuilder RequireHost(this IEndpointConventionBuilder builder, params string[] hosts)
         {
             if (builder == null)

src/Http/Routing/src/HostAttribute.cs

@@ -12,7 +12,8 @@ namespace Microsoft.AspNetCore.Routing
     /// Attribute for providing host metdata that is used during routing.
     /// </summary>
     [DebuggerDisplay("{DebuggerToString(),nq}")]
-    public class HostAttribute : IHostMetadata
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
+    public sealed class HostAttribute : Attribute, IHostMetadata
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="HostAttribute" /> class.

src/Http/Routing/src/Matching/HostMatcherPolicy.cs

@@ -8,7 +8,11 @@
 
 namespace Microsoft.AspNetCore.Routing.Matching
 {
-    public class HostMatcherPolicy : MatcherPolicy, IEndpointComparerPolicy, INodeBuilderPolicy
+    /// <summary>
+    /// An <see cref="MatcherPolicy"/> that implements filtering and selection by
+    /// the host header of a request.
+    /// </summary>
+    public sealed class HostMatcherPolicy : MatcherPolicy, IEndpointComparerPolicy, INodeBuilderPolicy
     {
         // Run after HTTP methods, but before 'default'.
         public override int Order { get; } = -100;