Add HostPolicyMatcher

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

@@ -0,0 +1,43 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Routing;
+
+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)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (hosts == null)
+            {
+                throw new ArgumentNullException(nameof(hosts));
+            }
+
+            builder.Add(endpointBuilder =>
+            {
+                endpointBuilder.Metadata.Add(new HostAttribute(hosts));
+            });
+            return builder;
+        }
+    }
+}

src/Http/Routing/src/DependencyInjection/RoutingServiceCollectionExtensions.cs

@@ -87,6 +87,7 @@ public static IServiceCollection AddRouting(this IServiceCollection services)
             //
             services.TryAddSingleton<EndpointSelector, DefaultEndpointSelector>();
             services.TryAddEnumerable(ServiceDescriptor.Singleton<MatcherPolicy, HttpMethodMatcherPolicy>());
+            services.TryAddEnumerable(ServiceDescriptor.Singleton<MatcherPolicy, HostMatcherPolicy>());
 
             //
             // Misc infrastructure

src/Http/Routing/src/HostAttribute.cs

@@ -0,0 +1,67 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace Microsoft.AspNetCore.Routing
+{
+    /// <summary>
+    /// Attribute for providing host metdata that is used during routing.
+    /// </summary>
+    [DebuggerDisplay("{DebuggerToString(),nq}")]
+    [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.
+        /// </summary>
+        /// <param name="host">
+        /// The host used during routing.
+        /// Host should be Unicode rather than punycode, and may have a port.
+        /// </param>
+        public HostAttribute(string host) : this(new[] { host })
+        {
+            if (host == null)
+            {
+                throw new ArgumentNullException(nameof(host));
+            }
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HostAttribute" /> class.
+        /// </summary>
+        /// <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>
+        public HostAttribute(params string[] hosts)
+        {
+            if (hosts == null)
+            {
+                throw new ArgumentNullException(nameof(hosts));
+            }
+
+            Hosts = hosts.ToArray();
+        }
+
+        /// <summary>
+        /// Returns a read-only collection of hosts used during routing.
+        /// Hosts will be Unicode rather than punycode, and may have a port.
+        /// An empty collection means any host will be accepted.
+        /// </summary>
+        public IReadOnlyList<string> Hosts { get; }
+
+        private string DebuggerToString()
+        {
+            var hostsDisplay = (Hosts.Count == 0)
+                ? "*:*"
+                : string.Join(",", Hosts.Select(h => h.Contains(':') ? h : h + ":*"));
+
+            return $"Hosts: {hostsDisplay}";
+        }
+    }
+}

src/Http/Routing/src/HttpMethodMetadata.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;

src/Http/Routing/src/IHostMetadata.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Routing
+{
+    /// <summary>
+    /// Represents host metadata used during routing.
+    /// </summary>
+    public interface IHostMetadata
+    {
+        /// <summary>
+        /// Returns a read-only collection of hosts used during routing.
+        /// Hosts will be Unicode rather than punycode, and may have a port.
+        /// An empty collection means any host will be accepted.
+        /// </summary>
+        IReadOnlyList<string> Hosts { get; }
+    }
+}