Changes due to davidfowl feedback

Changed dispatchers to IMatcher, added a context.

Removed a bunch of outdated cruft and updated the sample to use
attribute-routing like entries.

samples/DispatcherSample/Startup.cs

@@ -22,11 +22,10 @@ namespace DispatcherSample
             // This is a temporary layering issue, don't worry about :)
             services.AddRouting();
             services.AddSingleton<RouteTemplateUrlGenerator>();
-            services.AddSingleton<IDefaultDispatcherFactory, TreeDispatcherFactory>();
+            services.AddSingleton<IDefaultMatcherFactory, TreeMatcherFactory>();
 
             // Imagine this was done by MVC or another framework.
             services.AddSingleton<DispatcherDataSource>(ConfigureDispatcher());
-            services.AddSingleton<EndpointSelector, TemplateEndpointSelector>();
             services.AddSingleton<EndpointSelector, HttpMethodEndpointSelector>();
 
         }
@@ -37,18 +36,20 @@ namespace DispatcherSample
             {
                 Addresses =
                 {
-                    new TemplateAddress("{controller=Home}/{action=Index}/{id?}", new { controller = "Home", action = "Index", }, "Home:Index()"),
+                    new TemplateAddress("{id?}", new { controller = "Home", action = "Index", }, "Home:Index()"),
-                    new TemplateAddress("{controller=Home}/{action=Index}/{id?}", new { controller = "Home", action = "About", }, "Home:About()"),
+                    new TemplateAddress("Home/About/{id?}", new { controller = "Home", action = "About", }, "Home:About()"),
-                    new TemplateAddress("{controller=Home}/{action=Index}/{id?}", new { controller = "Admin", action = "Index", }, "Admin:Index()"),
+                    new TemplateAddress("Admin/Index/{id?}", new { controller = "Admin", action = "Index", }, "Admin:Index()"),
-                    new TemplateAddress("{controller=Home}/{action=Index}/{id?}", new { controller = "Admin", action = "Users", }, "Admin:GetUsers()/Admin:EditUsers()"),
+                    new TemplateAddress("Admin/Users/{id?}", new { controller = "Admin", action = "Users", }, "Admin:GetUsers()/Admin:EditUsers()"),
                 },
                 Endpoints =
                 {
-                    new TemplateEndpoint("{controller=Home}/{action=Index}/{id?}", new { controller = "Home", action = "Index", }, Home_Index, "Home:Index()"),
+                    new TemplateEndpoint("{id?}", new { controller = "Home", action = "Index", }, Home_Index, "Home:Index()"),
-                    new TemplateEndpoint("{controller=Home}/{action=Index}/{id?}", new { controller = "Home", action = "About", }, Home_About, "Home:About()"),
+                    new TemplateEndpoint("Home/{id?}", new { controller = "Home", action = "Index", }, Home_Index, "Home:Index()"),
-                    new TemplateEndpoint("{controller=Home}/{action=Index}/{id?}", new { controller = "Admin", action = "Index", }, Admin_Index, "Admin:Index()"),
+                    new TemplateEndpoint("Home/Index/{id?}", new { controller = "Home", action = "Index", }, Home_Index, "Home:Index()"),
-                    new TemplateEndpoint("{controller=Home}/{action=Index}/{id?}", new { controller = "Admin", action = "Users", }, "GET", Admin_GetUsers, "Admin:GetUsers()", new AuthorizationPolicyMetadata("Admin")),
+                    new TemplateEndpoint("Home/About/{id?}", new { controller = "Home", action = "About", }, Home_About, "Home:About()"),
-                    new TemplateEndpoint("{controller=Home}/{action=Index}/{id?}", new { controller = "Admin", action = "Users", }, "POST", Admin_EditUsers, "Admin:EditUsers()", new AuthorizationPolicyMetadata("Admin")),
+                    new TemplateEndpoint("Admin/Index/{id?}", new { controller = "Admin", action = "Index", }, Admin_Index, "Admin:Index()"),
+                    new TemplateEndpoint("Admin/Users/{id?}", new { controller = "Admin", action = "Users", }, "GET", Admin_GetUsers, "Admin:GetUsers()", new AuthorizationPolicyMetadata("Admin")),
+                    new TemplateEndpoint("Admin/Users/{id?}", new { controller = "Admin", action = "Users", }, "POST", Admin_EditUsers, "Admin:EditUsers()", new AuthorizationPolicyMetadata("Admin")),
                 },
             };
         }

src/Microsoft.AspNetCore.Dispatcher.Abstractions/IDispatcherFeature.cs

@@ -1,6 +1,7 @@
 // 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.Http;
 
 namespace Microsoft.AspNetCore.Dispatcher
@@ -9,7 +10,7 @@ namespace Microsoft.AspNetCore.Dispatcher
     {
         Endpoint Endpoint { get; set; }
 
-        RequestDelegate RequestDelegate { get; set; }
+        Func<RequestDelegate, RequestDelegate> Handler { get; set; }
 
         DispatcherValueCollection Values { get; set; }
     }

src/Microsoft.AspNetCore.Dispatcher/DefaultAddressTable.cs

@@ -21,10 +21,10 @@ namespace Microsoft.AspNetCore.Dispatcher
 
             _options = options.Value;
 
-            _groups = new List<Address>[options.Value.Dispatchers.Count];
+            _groups = new List<Address>[options.Value.Matchers.Count];
-            for (var i = 0; i < options.Value.Dispatchers.Count; i++)
+            for (var i = 0; i < options.Value.Matchers.Count; i++)
             {
-                _groups[i] = new List<Address>(options.Value.Dispatchers[i].AddressProvider?.Addresses ?? Array.Empty<Address>());
+                _groups[i] = new List<Address>(options.Value.Matchers[i].AddressProvider?.Addresses ?? Array.Empty<Address>());
             }
         }
 

src/Microsoft.AspNetCore.Dispatcher/DefaultDispatcherConfigureOptions.cs

@@ -10,12 +10,12 @@ namespace Microsoft.AspNetCore.Dispatcher
     internal class DefaultDispatcherConfigureOptions : IConfigureOptions<DispatcherOptions>
     {
         private readonly IEnumerable<DispatcherDataSource> _dataSources;
-        private readonly IDefaultDispatcherFactory _dispatcherFactory;
+        private readonly IDefaultMatcherFactory _dispatcherFactory;
         private readonly IEnumerable<EndpointSelector> _endpointSelectors;
         private readonly IEnumerable<EndpointHandlerFactoryBase> _handlerFactories;
 
         public DefaultDispatcherConfigureOptions(
-            IDefaultDispatcherFactory dispatcherFactory,
+            IDefaultMatcherFactory dispatcherFactory,
             IEnumerable<DispatcherDataSource> dataSources,
             IEnumerable<EndpointSelector> endpointSelectors,
             IEnumerable<EndpointHandlerFactoryBase> handlerFactories)
@@ -33,7 +33,7 @@ namespace Microsoft.AspNetCore.Dispatcher
                 throw new ArgumentNullException(nameof(options));
             }
 
-            options.Dispatchers.Add(_dispatcherFactory.CreateDispatcher(new CompositeDispatcherDataSource(_dataSources), _endpointSelectors));
+            options.Matchers.Add(_dispatcherFactory.CreateDispatcher(new CompositeDispatcherDataSource(_dataSources), _endpointSelectors));
 
             foreach (var handlerFactory in _handlerFactories)
             {

src/Microsoft.AspNetCore.Dispatcher/DispatcherCollection.cs

@@ -1,40 +0,0 @@
-// 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.ObjectModel;
-using Microsoft.AspNetCore.Http;
-
-namespace Microsoft.AspNetCore.Dispatcher
-{
-    public class DispatcherCollection : Collection<DispatcherEntry>
-    {
-        public void Add(DispatcherBase dispatcher)
-        {
-            if (dispatcher == null)
-            {
-                throw new ArgumentNullException(nameof(dispatcher));
-            }
-
-            Add(new DispatcherEntry()
-            {
-                Dispatcher = dispatcher.InvokeAsync,
-                AddressProvider  = dispatcher,
-                EndpointProvider = dispatcher,
-            });
-        }
-
-        public void Add(RequestDelegate dispatcher)
-        {
-            if (dispatcher == null)
-            {
-                throw new ArgumentNullException(nameof(dispatcher));
-            }
-
-            Add(new DispatcherEntry()
-            {
-                Dispatcher = dispatcher,
-            });
-        }
-    }
-}

src/Microsoft.AspNetCore.Dispatcher/DispatcherFeature.cs

@@ -1,6 +1,7 @@
 // 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.Http;
 
 namespace Microsoft.AspNetCore.Dispatcher
@@ -9,7 +10,7 @@ namespace Microsoft.AspNetCore.Dispatcher
     {
         public Endpoint Endpoint { get; set; }
 
-        public RequestDelegate RequestDelegate { get; set; }
+        public Func<RequestDelegate, RequestDelegate> Handler { get; set; }
 
         public DispatcherValueCollection Values { get; set; }
     }

src/Microsoft.AspNetCore.Dispatcher/DispatcherLoggerExtensions.cs

@@ -31,9 +31,9 @@ namespace Microsoft.AspNetCore.Dispatcher
             _ambiguousEndpoints(logger, ambiguousEndpoints, null);
         }
 
-        public static void EndpointMatched(this ILogger logger, string endpointName)
+        public static void EndpointMatched(this ILogger logger, Endpoint endpoint)
         {
-            _endpointMatched(logger, endpointName ?? "Unnamed endpoint", null);
+            _endpointMatched(logger, endpoint.DisplayName ?? "Unnamed endpoint", null);
         }
 
         public static void NoEndpointsMatched(this ILogger logger, PathString pathString)

src/Microsoft.AspNetCore.Dispatcher/DispatcherMiddleware.cs

@@ -42,12 +42,38 @@ namespace Microsoft.AspNetCore.Dispatcher
             var feature = new DispatcherFeature();
             httpContext.Features.Set<IDispatcherFeature>(feature);
 
-            foreach (var entry in _options.Dispatchers)
+            var context = new MatcherContext(httpContext);
+            foreach (var entry in _options.Matchers)
             {
-                await entry.Dispatcher(httpContext);
+                await entry.Matcher.MatchAsync(context);
-                if (feature.Endpoint != null || feature.RequestDelegate != null)
+
+                if (context.ShortCircuit != null)
                 {
-                    _logger.LogInformation("Matched endpoint {Endpoint}", feature.Endpoint.DisplayName);
+                    feature.Endpoint = context.Endpoint;
+                    feature.Values = context.Values;
+
+                    await context.ShortCircuit(httpContext);
+                    return;
+                }
+
+                if (context.Endpoint != null)
+                {
+                    _logger.LogInformation("Matched endpoint {Endpoint}", context.Endpoint.DisplayName);
+
+                    feature.Endpoint = context.Endpoint;
+                    feature.Values = context.Values;
+
+                    // Associate this with the DispatcherEntry, not global
+                    for (var i = 0; i < _options.HandlerFactories.Count; i++)
+                    {
+                        var middleware = _options.HandlerFactories[i](feature.Endpoint);
+                        if (middleware != null)
+                        {
+                            feature.Handler = middleware;
+                            break;
+                        }
+                    }
+
                     break;
                 }
             }

src/Microsoft.AspNetCore.Dispatcher/DispatcherOptions.cs

@@ -7,7 +7,7 @@ namespace Microsoft.AspNetCore.Dispatcher
 {
     public class DispatcherOptions
     {
-        public DispatcherCollection Dispatchers { get; } = new DispatcherCollection();
+        public MatcherCollection Matchers { get; } = new MatcherCollection();
 
         public IList<EndpointHandlerFactory> HandlerFactories { get; } = new List<EndpointHandlerFactory>();
     }

src/Microsoft.AspNetCore.Dispatcher/EndpointMiddleware.cs

@@ -37,28 +37,15 @@ namespace Microsoft.AspNetCore.Dispatcher
             _next = next;
         }
 
-        public async Task Invoke(HttpContext context)
+        public async Task Invoke(HttpContext httpContext)
         {
-            var feature = context.Features.Get<IDispatcherFeature>();
+            var feature = httpContext.Features.Get<IDispatcherFeature>();
-            if (feature.Endpoint != null && feature.RequestDelegate == null)
+            if (feature.Handler != null)
-            {
-                for (var i = 0; i < _options.HandlerFactories.Count; i++)
-                {
-                    var handler = _options.HandlerFactories[i](feature.Endpoint);
-                    if (handler != null)
-                    {
-                        feature.RequestDelegate = handler(_next);
-                        break;
-                    }
-                }
-            }
-
-            if (feature.RequestDelegate != null)
             {
                 _logger.LogInformation("Executing endpoint {Endpoint}", feature.Endpoint.DisplayName);
                 try
                 {
-                    await feature.RequestDelegate(context);
+                    await feature.Handler(_next)(httpContext);
                 }
                 finally
                 {
@@ -68,7 +55,7 @@ namespace Microsoft.AspNetCore.Dispatcher
                 return;
             }
 
-            await _next(context);
+            await _next(httpContext);
         }
     }
 }

src/Microsoft.AspNetCore.Dispatcher/EndpointSelectorContext.cs

@@ -13,13 +13,18 @@ namespace Microsoft.AspNetCore.Dispatcher
     {
         private int _index;
 
-        public EndpointSelectorContext(HttpContext httpContext, IList<Endpoint> endpoints, IList<EndpointSelector> selectors)
+        public EndpointSelectorContext(HttpContext httpContext, DispatcherValueCollection values, IList<Endpoint> endpoints, IList<EndpointSelector> selectors)
         {
             if (httpContext == null)
             {
                 throw new ArgumentNullException(nameof(httpContext));
             }
 
+            if (values == null)
+            {
+                throw new ArgumentNullException(nameof(values));
+            }
+
             if (endpoints == null)
             {
                 throw new ArgumentNullException(nameof(endpoints));
@@ -31,6 +36,7 @@ namespace Microsoft.AspNetCore.Dispatcher
             }
 
             HttpContext = httpContext;
+            Values = values;
             Endpoints = endpoints;
             Selectors = selectors; 
         }
@@ -41,6 +47,10 @@ namespace Microsoft.AspNetCore.Dispatcher
 
         public IList<EndpointSelector> Selectors { get; }
 
+        public RequestDelegate ShortCircuit { get; set; }
+
+        public DispatcherValueCollection Values { get; }
+
         public Task InvokeNextAsync()
         {
             if (_index >= Selectors.Count)

src/Microsoft.AspNetCore.Dispatcher/IDefaultMatcherFactory.cs

@@ -5,8 +5,8 @@ using System.Collections.Generic;
 
 namespace Microsoft.AspNetCore.Dispatcher
 {
-    public interface IDefaultDispatcherFactory
+    public interface IDefaultMatcherFactory
     {
-        DispatcherEntry CreateDispatcher(DispatcherDataSource dataSource, IEnumerable<EndpointSelector> endpointSelectors);
+        MatcherEntry CreateDispatcher(DispatcherDataSource dataSource, IEnumerable<EndpointSelector> endpointSelectors);
     }
 }

src/Microsoft.AspNetCore.Dispatcher/IMatcher.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.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Dispatcher
+{
+    /// <summary>
+    /// An interface for components that can select an <see cref="Endpoint"/> given the current request, as part
+    /// of the execution of <see cref="DispatcherMiddleware"/>.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// <see cref="IMatcher"/> implementations can also optionally implement the <see cref="IEndpointCollectionProvider"/>
+    /// and <see cref="IAddressCollectionProvider"/> interfaces to provide addition information.
+    /// </para>
+    /// <para>
+    /// Use <see cref="DispatcherOptions"/> to register instances of <see cref="IMatcher"/> that will be used by the
+    /// <see cref="DispatcherMiddleware"/>.
+    /// </para>
+    /// </remarks>
+    public interface IMatcher
+    {
+        /// <summary>
+        /// Attempts to asynchronously select an <see cref="Endpoint"/> for the current request.
+        /// </summary>
+        /// <param name="context">The <see cref="MatcherContext"/> associated with the current request.</param>
+        /// <returns>A <see cref="Task"/> which represents the asynchronous completion of the operation.</returns>
+        /// <remarks>
+        /// <para>
+        /// An implementation should use data from the current request (<see cref="MatcherContext.HttpContext"/>) to select the
+        /// <see cref="Endpoint"/> and set <see cref="MatcherContext.Endpoint"/> and optionally <see cref="MatcherContext.Values"/>
+        /// to indicate a successful result.
+        /// </para>
+        /// <para>
+        /// If the matcher encounters an immediate failure condition, the implementation should set
+        /// <see cref="MatcherContext.ShortCircuit"/> to a <see cref="RequestDelegate"/> that will respond to the current request.
+        /// </para>
+        /// </remarks>
+        Task MatchAsync(MatcherContext context);
+    }
+}

src/Microsoft.AspNetCore.Dispatcher/MatcherBase.cs

@@ -14,23 +14,22 @@ using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNetCore.Dispatcher
 {
-    public abstract class DispatcherBase : IAddressCollectionProvider, IEndpointCollectionProvider
+    public abstract class MatcherBase : IMatcher, IAddressCollectionProvider, IEndpointCollectionProvider
     {
         private List<Address> _addresses;
         private List<Endpoint> _endpoints;
         private List<EndpointSelector> _endpointSelectors;
 
-        private object _initialize;
-        private bool _selectorsInitialized;
-        private readonly Func<object> _initializer;
         private object _lock;
-
         private bool _servicesInitialized;
+        private bool _selectorsInitialized;
+        private readonly Func<object> _selectorInitializer;
 
-        public DispatcherBase()
+
+        public MatcherBase()
         {
             _lock = new object();
-            _initializer = InitializeSelectors;
+            _selectorInitializer = InitializeSelectors;
         }
 
         protected ILogger Logger { get; private set; }
@@ -92,39 +91,37 @@ namespace Microsoft.AspNetCore.Dispatcher
             return ((IEndpointCollectionProvider)DataSource)?.Endpoints ?? _endpoints ?? (IReadOnlyList<Endpoint>)Array.Empty<Endpoint>();
         }
 
-        public virtual async Task InvokeAsync(HttpContext httpContext)
+        public virtual async Task MatchAsync(MatcherContext context)
         {
-            if (httpContext == null)
+            if (context == null)
             {
-                throw new ArgumentNullException(nameof(httpContext));
+                throw new ArgumentNullException(nameof(context));
             }
 
-            EnsureServicesInitialized(httpContext);
+            EnsureServicesInitialized(context);
 
-            var feature = httpContext.Features.Get<IDispatcherFeature>();
+            context.Values = await MatchRequestAsync(context.HttpContext);
-            if (await TryMatchAsync(httpContext))
+            if (context.Values != null)
             {
-                if (feature.RequestDelegate != null)
+                await SelectEndpointAsync(context, GetEndpoints());
-                {
-                    // Short circuit, no need to select an endpoint.
-                    return;
-                }
-
-                feature.Endpoint = await SelectEndpointAsync(httpContext, GetEndpoints(), Selectors);
             }
         }
 
-        protected virtual Task<bool> TryMatchAsync(HttpContext httpContext)
+        protected virtual Task<DispatcherValueCollection> MatchRequestAsync(HttpContext httpContext)
         {
-            // By default don't apply any criteria.
+            // By default don't apply any criteria or provide any values.
-            return Task.FromResult(true);
+            return Task.FromResult(new DispatcherValueCollection());
         }
 
-        protected virtual async Task<Endpoint> SelectEndpointAsync(HttpContext httpContext, IEnumerable<Endpoint> endpoints, IEnumerable<EndpointSelector> selectors)
+        protected virtual void InitializeServices(IServiceProvider services)
         {
-            if (httpContext == null)
+        }
+
+        protected virtual async Task SelectEndpointAsync(MatcherContext context, IEnumerable<Endpoint> endpoints)
+        {
+            if (context == null)
             {
-                throw new ArgumentNullException(nameof(httpContext));
+                throw new ArgumentNullException(nameof(context));
             }
 
             if (endpoints == null)
@@ -132,25 +129,28 @@ namespace Microsoft.AspNetCore.Dispatcher
                 throw new ArgumentNullException(nameof(endpoints));
             }
 
-            if (selectors == null)
+            EnsureSelectorsInitialized();
-            {
-                throw new ArgumentNullException(nameof(selectors));
-            }
 
-            LazyInitializer.EnsureInitialized(ref _initialize, ref _selectorsInitialized, ref _lock, _initializer);
+            var selectorContext = new EndpointSelectorContext(context.HttpContext, context.Values, endpoints.ToList(), Selectors.ToList());
-
-            var selectorContext = new EndpointSelectorContext(httpContext, endpoints.ToList(), selectors.ToList());
             await selectorContext.InvokeNextAsync();
 
+            if (selectorContext.ShortCircuit != null)
+            {
+                context.ShortCircuit = selectorContext.ShortCircuit;
+                return;
+            }
+
             switch (selectorContext.Endpoints.Count)
             {
                 case 0:
-                    Logger.NoEndpointsMatched(httpContext.Request.Path);
+                    Logger.NoEndpointsMatched(context.HttpContext.Request.Path);
-                    return null;
+                    return;
 
                 case 1:
-                    Logger.EndpointMatched(selectorContext.Endpoints[0].DisplayName);
+                    context.Endpoint = selectorContext.Endpoints[0];
-                    return selectorContext.Endpoints[0];
+
+                    Logger.EndpointMatched(context.Endpoint);
+                    return;
 
                 default:
                     var endpointNames = string.Join(
@@ -167,6 +167,12 @@ namespace Microsoft.AspNetCore.Dispatcher
             }
         }
 
+        protected void EnsureSelectorsInitialized()
+        {
+            object _ = null;
+            LazyInitializer.EnsureInitialized(ref _, ref _selectorsInitialized, ref _lock, _selectorInitializer);
+        }
+
         private object InitializeSelectors()
         {
             foreach (var selector in Selectors)
@@ -177,23 +183,25 @@ namespace Microsoft.AspNetCore.Dispatcher
             return null;
         }
 
-        protected void EnsureServicesInitialized(HttpContext httpContext)
+        protected void EnsureServicesInitialized(MatcherContext context)
         {
             if (Volatile.Read(ref _servicesInitialized))
             {
                 return;
             }
 
-            EnsureServicesInitializedSlow(httpContext);
+            EnsureServicesInitializedSlow(context);
         }
 
-        private void EnsureServicesInitializedSlow(HttpContext httpContext)
+        private void EnsureServicesInitializedSlow(MatcherContext context)
         {
             lock (_lock)
             {
                 if (!Volatile.Read(ref _servicesInitialized))
                 {
-                    Logger = httpContext.RequestServices.GetRequiredService<ILoggerFactory>().CreateLogger(GetType());
+                    var services = context.HttpContext.RequestServices;
+                    Logger = services.GetRequiredService<ILoggerFactory>().CreateLogger(GetType());
+                    InitializeServices(services);
                 }
             }
         }

src/Microsoft.AspNetCore.Dispatcher/MatcherCollection.cs

@@ -0,0 +1,39 @@
+// 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.ObjectModel;
+
+namespace Microsoft.AspNetCore.Dispatcher
+{
+    public class MatcherCollection : Collection<MatcherEntry>
+    {
+        public void Add(MatcherBase matcher)
+        {
+            if (matcher == null)
+            {
+                throw new ArgumentNullException(nameof(matcher));
+            }
+
+            Add(new MatcherEntry()
+            {
+                Matcher = matcher,
+                AddressProvider  = matcher,
+                EndpointProvider = matcher,
+            });
+        }
+
+        public void Add(IMatcher matcher)
+        {
+            if (matcher == null)
+            {
+                throw new ArgumentNullException(nameof(matcher));
+            }
+
+            Add(new MatcherEntry()
+            {
+                Matcher = matcher,
+            });
+        }
+    }
+}

src/Microsoft.AspNetCore.Dispatcher/MatcherContext.cs

@@ -0,0 +1,48 @@
+// 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.Http;
+
+namespace Microsoft.AspNetCore.Dispatcher
+{
+    /// <summary>
+    /// A context object for <see cref="IMatcher.MatchAsync(MatcherContext)"/>.
+    /// </summary>
+    public class MatcherContext
+    {
+        /// <summary>
+        /// Creates a new <see cref="MatcherContext"/> for the current request.
+        /// </summary>
+        /// <param name="httpContext">The <see cref="Http.HttpContext"/> associated with the current request.</param>
+        public MatcherContext(HttpContext httpContext)
+        {
+            if (httpContext == null)
+            {
+                throw new ArgumentNullException(nameof(httpContext));
+            }
+
+            HttpContext = httpContext;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="Http.HttpContext"/> associated with the current request.
+        /// </summary>
+        public HttpContext HttpContext { get; }
+
+        /// <summary>
+        /// Gets or sets the <see cref="Endpoint"/> selected by the matcher.
+        /// </summary>
+        public Endpoint Endpoint { get; set; }
+
+        /// <summary>
+        /// Gets or sets a short-circuit delegate provided by the matcher.
+        /// </summary>
+        public RequestDelegate ShortCircuit { get; set; }
+
+        /// <summary>
+        /// Gets or sets a <see cref="DispatcherValueCollection"/> provided by the matcher.
+        /// </summary>
+        public DispatcherValueCollection Values { get; set; }
+    }
+}

src/Microsoft.AspNetCore.Dispatcher/MatcherEntry.cs

@@ -1,13 +1,11 @@
 // 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 Microsoft.AspNetCore.Http;
-
 namespace Microsoft.AspNetCore.Dispatcher
 {
-    public class DispatcherEntry
+    public class MatcherEntry
     {
-        public RequestDelegate Dispatcher { get; set; }
+        public IMatcher Matcher { get; set; }
 
         public IAddressCollectionProvider AddressProvider { get; set; }
 

src/Microsoft.AspNetCore.Dispatcher/TemplateEndpointSelector.cs

@@ -1,55 +0,0 @@
-// 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.Threading.Tasks;
-
-namespace Microsoft.AspNetCore.Dispatcher
-{
-    public class TemplateEndpointSelector : EndpointSelector
-    {
-        public override Task SelectAsync(EndpointSelectorContext context)
-        {
-            if (context == null)
-            {
-                throw new ArgumentNullException(nameof(context));
-            }
-
-            var dispatcherFeature = context.HttpContext.Features.Get<IDispatcherFeature>();
-
-            for (var i = context.Endpoints.Count - 1; i >= 0; i--)
-            {
-                var endpoint = context.Endpoints[i] as ITemplateEndpoint;
-                if (!CompareRouteValues(dispatcherFeature.Values, endpoint.Values))
-                {
-                    context.Endpoints.RemoveAt(i);
-                }
-            }
-            
-            return context.InvokeNextAsync();
-        }
-        
-        private bool CompareRouteValues(DispatcherValueCollection values, DispatcherValueCollection requiredValues)
-        {
-            foreach (var kvp in requiredValues)
-            {
-                if (string.IsNullOrEmpty(kvp.Value.ToString()))
-                {
-                    if (values.TryGetValue(kvp.Key, out var routeValue) && !string.IsNullOrEmpty(routeValue.ToString()))
-                    {
-                        return false;
-                    }
-                }
-                else
-                {
-                    if (!values.TryGetValue(kvp.Key, out var routeValue) || !string.Equals(kvp.Value.ToString(), routeValue.ToString(), StringComparison.OrdinalIgnoreCase))
-                    {
-                        return false;
-                    }
-                }
-            }
-
-            return true;
-        }
-    }
-}

src/Microsoft.AspNetCore.Routing/Dispatcher/RouteTemplateDispatcher.cs

@@ -1,157 +0,0 @@
-// 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.Threading.Tasks;
-using Microsoft.AspNetCore.Dispatcher;
-using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Routing.Template;
-
-namespace Microsoft.AspNetCore.Routing.Dispatcher
-{
-    public class RouteTemplateDispatcher : DispatcherBase
-    {
-        private readonly IDictionary<string, IRouteConstraint> _constraints;
-        private readonly RouteValueDictionary _defaults;
-        private readonly TemplateMatcher _matcher;
-        private readonly RouteTemplate _parsedTemplate;
-
-        public RouteTemplateDispatcher(
-            string routeTemplate,
-            IInlineConstraintResolver constraintResolver)
-            : this(routeTemplate, constraintResolver, null, null)
-        {
-        }
-
-        public RouteTemplateDispatcher(
-            string routeTemplate,
-            IInlineConstraintResolver constraintResolver,
-            RouteValueDictionary defaults)
-            : this(routeTemplate, constraintResolver, defaults, null)
-        {
-        }
-
-        public RouteTemplateDispatcher(
-            string routeTemplate,
-            IInlineConstraintResolver constraintResolver,
-            RouteValueDictionary defaults,
-            IDictionary<string, object> constraints)
-        {
-            if (routeTemplate == null)
-            {
-                throw new ArgumentNullException(nameof(routeTemplate));
-            }
-
-            if (constraintResolver == null)
-            {
-                throw new ArgumentNullException(nameof(constraintResolver));
-            }
-
-            RouteTemplate = routeTemplate;
-
-            try
-            {
-                // Data we parse from the template will be used to fill in the rest of the constraints or
-                // defaults. The parser will throw for invalid routes.
-                _parsedTemplate = TemplateParser.Parse(routeTemplate);
-
-                _constraints = GetConstraints(constraintResolver, _parsedTemplate, constraints);
-                _defaults = GetDefaults(_parsedTemplate, defaults);
-            }
-            catch (Exception exception)
-            {
-                throw new RouteCreationException(Resources.FormatTemplateRoute_Exception(string.Empty, routeTemplate), exception);
-            }
-
-            _matcher = new TemplateMatcher(_parsedTemplate, _defaults);
-        }
-
-        public string RouteTemplate { get; }
-
-        protected override Task<bool> TryMatchAsync(HttpContext httpContext)
-        {
-            if (httpContext == null)
-            {
-                throw new ArgumentNullException(nameof(httpContext));
-            }
-
-            var feature = httpContext.Features.Get<IDispatcherFeature>();
-            feature.Values = feature.Values ?? new RouteValueDictionary();
-
-            if (!_matcher.TryMatch(httpContext.Request.Path, (RouteValueDictionary)feature.Values))
-            {
-                // If we got back a null value set, that means the URI did not match
-                return Task.FromResult(false);
-            }
-
-            foreach (var kvp in _constraints)
-            {
-                var constraint = kvp.Value;
-                if (!constraint.Match(httpContext, null, kvp.Key, (RouteValueDictionary)feature.Values, RouteDirection.IncomingRequest))
-                {
-                    return Task.FromResult(false);
-                }
-            }
-
-            return Task.FromResult(true);
-        }
-
-        private static IDictionary<string, IRouteConstraint> GetConstraints(
-            IInlineConstraintResolver inlineConstraintResolver,
-            RouteTemplate parsedTemplate,
-            IDictionary<string, object> constraints)
-        {
-            var constraintBuilder = new RouteConstraintBuilder(inlineConstraintResolver, parsedTemplate.TemplateText);
-
-            if (constraints != null)
-            {
-                foreach (var kvp in constraints)
-                {
-                    constraintBuilder.AddConstraint(kvp.Key, kvp.Value);
-                }
-            }
-
-            foreach (var parameter in parsedTemplate.Parameters)
-            {
-                if (parameter.IsOptional)
-                {
-                    constraintBuilder.SetOptional(parameter.Name);
-                }
-
-                foreach (var inlineConstraint in parameter.InlineConstraints)
-                {
-                    constraintBuilder.AddResolvedConstraint(parameter.Name, inlineConstraint.Constraint);
-                }
-            }
-
-            return constraintBuilder.Build();
-        }
-
-        private static RouteValueDictionary GetDefaults(
-            RouteTemplate parsedTemplate,
-            RouteValueDictionary defaults)
-        {
-            var result = defaults == null ? new RouteValueDictionary() : new RouteValueDictionary(defaults);
-
-            foreach (var parameter in parsedTemplate.Parameters)
-            {
-                if (parameter.DefaultValue != null)
-                {
-                    if (result.ContainsKey(parameter.Name))
-                    {
-                        throw new InvalidOperationException(
-                          Resources.FormatTemplateRoute_CannotHaveDefaultValueSpecifiedInlineAndExplicitly(
-                              parameter.Name));
-                    }
-                    else
-                    {
-                        result.Add(parameter.Name, parameter.DefaultValue);
-                    }
-                }
-            }
-
-            return result;
-        }
-    }
-}

src/Microsoft.AspNetCore.Routing/Dispatcher/RouterDispatcher.cs

@@ -1,72 +0,0 @@
-// 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.Threading.Tasks;
-using Microsoft.AspNetCore.Dispatcher;
-using Microsoft.AspNetCore.Http;
-
-namespace Microsoft.AspNetCore.Routing.Dispatcher
-{
-    /// <summary>
-    /// An adapter to plug an <see cref="IRouter"/> into a dispatcher.
-    /// </summary>
-    public class RouterDispatcher : DispatcherBase
-    {
-        private readonly Endpoint _fallbackEndpoint;
-        private readonly IRouter _router;
-
-        public RouterDispatcher(IRouter router)
-        {
-            if (router == null)
-            {
-                throw new ArgumentNullException(nameof(router));
-            }
-
-            _router = router;
-            _fallbackEndpoint = new UnknownEndpoint(_router);
-        }
-
-        protected override async Task<bool> TryMatchAsync(HttpContext httpContext)
-        {
-            if (httpContext == null)
-            {
-                throw new ArgumentNullException(nameof(httpContext));
-            }
-            
-            var routeContext = new RouteContext(httpContext);
-            await _router.RouteAsync(routeContext);
-
-            var feature = httpContext.Features.Get<IDispatcherFeature>();
-            if (routeContext.Handler == null)
-            {
-                // The route did not match, clear everything as it may have been set by the route.
-                feature.Endpoint = null;
-                feature.RequestDelegate = null;
-                feature.Values = null;
-                return false;
-            }
-            else
-            {
-                feature.Endpoint = feature.Endpoint ?? _fallbackEndpoint;
-                feature.RequestDelegate = routeContext.Handler;
-                feature.Values = routeContext.RouteData.Values;
-                return true;
-            }
-        }
-
-        private class UnknownEndpoint : Endpoint
-        {
-            public UnknownEndpoint(IRouter router)
-            {
-                DisplayName = $"Endpoint for '{router}";
-            }
-
-            public override string DisplayName { get; }
-
-            public override IReadOnlyList<object> Metadata => Array.Empty<object>();
-        }
-    }
-}
-

src/Microsoft.AspNetCore.Routing/Dispatcher/TreeMatcher.cs

@@ -5,7 +5,6 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Dispatcher;
@@ -15,11 +14,10 @@ using Microsoft.AspNetCore.Routing.Logging;
 using Microsoft.AspNetCore.Routing.Template;
 using Microsoft.AspNetCore.Routing.Tree;
 using Microsoft.Extensions.Internal;
-using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Routing.Dispatcher
 {
-    public class TreeDispatcher : DispatcherBase
+    public class TreeMatcher : MatcherBase
     {
         private bool _dataInitialized;
         private object _lock;
@@ -27,31 +25,30 @@ namespace Microsoft.AspNetCore.Routing.Dispatcher
 
         private readonly Func<Cache> _initializer;
 
-        public TreeDispatcher()
+        public TreeMatcher()
         {
             _lock = new object();
             _initializer = CreateCache;
         }
 
-        public override async Task InvokeAsync(HttpContext httpContext)
+        public override async Task MatchAsync(MatcherContext context)
         {
-            if (httpContext == null)
+            if (context == null)
             {
-                throw new ArgumentNullException(nameof(httpContext));
+                throw new ArgumentNullException(nameof(context));
             }
 
-            EnsureServicesInitialized(httpContext);
+            EnsureServicesInitialized(context);
 
             var cache = LazyInitializer.EnsureInitialized(ref _cache, ref _dataInitialized, ref _lock, _initializer);
 
-            var feature = httpContext.Features.Get<IDispatcherFeature>();
+            var values = new RouteValueDictionary();
-            var values = feature.Values?.AsRouteValueDictionary() ?? new RouteValueDictionary();
+            context.Values = values;
-            feature.Values = values;
 
             for (var i = 0; i < cache.Trees.Length; i++)
             {
                 var tree = cache.Trees[i];
-                var tokenizer = new PathTokenizer(httpContext.Request.Path);
+                var tokenizer = new PathTokenizer(context.HttpContext.Request.Path);
 
                 var treenumerator = new Treenumerator(tree.Root, tokenizer);
 
@@ -64,23 +61,36 @@ namespace Microsoft.AspNetCore.Routing.Dispatcher
                         var matcher = item.TemplateMatcher;
 
                         values.Clear();
-                        if (!matcher.TryMatch(httpContext.Request.Path, values))
+                        if (!matcher.TryMatch(context.HttpContext.Request.Path, values))
                         {
                             continue;
                         }
 
                         Logger.MatchedRoute(entry.RouteName, entry.RouteTemplate.TemplateText);
 
-                        if (!MatchConstraints(httpContext, values, entry.Constraints))
+                        if (!MatchConstraints(context.HttpContext, values, entry.Constraints))
                         {
                             continue;
                         }
 
-                        feature.Endpoint = await SelectEndpointAsync(httpContext, (Endpoint[])entry.Tag, Selectors);
+                        await SelectEndpointAsync(context, (Endpoint[])entry.Tag);
-                        if (feature.Endpoint != null || feature.RequestDelegate != null)
+                        if (context.ShortCircuit != null)
                         {
                             return;
                         }
+
+                        if (context.Endpoint != null)
+                        {
+                            if (context.Endpoint is ITemplateEndpoint templateEndpoint)
+                            {
+                                foreach (var kvp in templateEndpoint.Values)
+                                {
+                                    context.Values[kvp.Key] = kvp.Value;
+                                }
+                            }
+
+                            return;
+                        }
                     }
                 }
             }

src/Microsoft.AspNetCore.Routing/Dispatcher/TreeMatcherFactory.cs

@@ -7,30 +7,30 @@ using Microsoft.AspNetCore.Dispatcher;
 
 namespace Microsoft.AspNetCore.Routing.Dispatcher
 {
-    public class TreeDispatcherFactory : IDefaultDispatcherFactory
+    public class TreeMatcherFactory : IDefaultMatcherFactory
     {
-        public DispatcherEntry CreateDispatcher(DispatcherDataSource dataSource, IEnumerable<EndpointSelector> endpointSelectors)
+        public MatcherEntry CreateDispatcher(DispatcherDataSource dataSource, IEnumerable<EndpointSelector> endpointSelectors)
         {
             if (dataSource == null)
             {
                 throw new ArgumentNullException(nameof(dataSource));
             }
 
-            var dispatcher = new TreeDispatcher()
+            var matcher = new TreeMatcher()
             {
                 DataSource = dataSource,
             };
 
             foreach (var endpointSelector in endpointSelectors)
             {
-                dispatcher.Selectors.Add(endpointSelector);
+                matcher.Selectors.Add(endpointSelector);
             }
 
-            return new DispatcherEntry()
+            return new MatcherEntry()
             {
-                AddressProvider = dispatcher,
+                AddressProvider = matcher,
-                Dispatcher = dispatcher.InvokeAsync,
+                Matcher = matcher,
-                EndpointProvider = dispatcher,
+                EndpointProvider = matcher,
             };
         }
     }

test/Microsoft.AspNetCore.Dispatcher.FunctionalTest/ApiAppStartup.cs

@@ -21,7 +21,7 @@ namespace Microsoft.AspNetCore.Dispatcher.FunctionalTest
             // This is a temporary layering issue, don't worry about it :)
             services.AddRouting();
             services.AddSingleton<RouteTemplateUrlGenerator>();
-            services.AddSingleton<IDefaultDispatcherFactory, TreeDispatcherFactory>();
+            services.AddSingleton<IDefaultMatcherFactory, TreeMatcherFactory>();
 
             services.Configure<DispatcherOptions>(ConfigureDispatcher);
         }
@@ -58,7 +58,7 @@ namespace Microsoft.AspNetCore.Dispatcher.FunctionalTest
 
         public void ConfigureDispatcher(DispatcherOptions options)
         {
-            options.Dispatchers.Add(new TreeDispatcher()
+            options.Matchers.Add(new TreeMatcher()
             {
                 Endpoints =
                 {

test/Microsoft.AspNetCore.Dispatcher.Test/HttpMethodEndpointSelectorTest.cs

@@ -84,13 +84,14 @@ namespace Microsoft.AspNetCore.Dispatcher
         {
             var httpContext = new DefaultHttpContext();
             httpContext.Request.Method = httpMethod;
+
             var selector = new HttpMethodEndpointSelector();
             var selectors = new List<EndpointSelector>()
             {
                 selector
             };
 
-            var selectorContext = new EndpointSelectorContext(httpContext, endpoints, selectors);
+            var selectorContext = new EndpointSelectorContext(httpContext, new DispatcherValueCollection(), endpoints, selectors);
             return (selectorContext, selector);
         }