Add documentation for Routing surface area (#26513)

* Add documentation for Routing surface area

* Apply suggestions from code review

Co-authored-by: James Newton-King <james@newtonking.com>

* Fix up some doc strings

Co-authored-by: James Newton-King <james@newtonking.com>

src/Http/Http.Abstractions/src/StatusCodes.cs

@@ -4,7 +4,7 @@
 namespace Microsoft.AspNetCore.Http
 {
     /// <summary>
-    /// A collection of contants for HTTP status codes.
+    /// A collection of constants for HTTP status codes.
     ///
     /// Status Codes listed at http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
     /// </summary>

src/Http/Routing.Abstractions/src/IRouteHandler.cs

@@ -6,7 +6,7 @@ using Microsoft.AspNetCore.Http;
 namespace Microsoft.AspNetCore.Routing
 {
     /// <summary>
-    /// Defines a contract for a handler of a route. 
+    /// Defines a contract for a handler of a route.
     /// </summary>
     public interface IRouteHandler
     {

src/Http/Routing.Abstractions/src/IRouter.cs

@@ -6,7 +6,7 @@ using System.Threading.Tasks;
 namespace Microsoft.AspNetCore.Routing
 {
     /// <summary>
-    ///
+    /// Interface for implementing a router.
     /// </summary>
     public interface IRouter
     {

src/Http/Routing/perf/Matching/MatcherBuilderMultipleEntryBenchmark.cs

@@ -205,4 +205,4 @@ namespace Microsoft.AspNetCore.Routing.Matching
             }
         }
     }
-}
+}

src/Http/Routing/src/Builder/EndpointRoutingApplicationBuilderExtensions.cs

@@ -9,6 +9,9 @@ using Microsoft.Extensions.Options;
 
 namespace Microsoft.AspNetCore.Builder
 {
+    /// <summary>
+    /// Constains extensions for configuring routing on an <see cref="IApplicationBuilder"/>.
+    /// </summary>
     public static class EndpointRoutingApplicationBuilderExtensions
     {
         private const string EndpointRouteBuilder = "__EndpointRouteBuilder";

src/Http/Routing/src/CompositeEndpointDataSource.cs

@@ -40,6 +40,11 @@ namespace Microsoft.AspNetCore.Routing
             _dataSources = dataSources;
         }
 
+        /// <summary>
+        /// Instantiates a <see cref="CompositeEndpointDataSource"/> object from <paramref name="endpointDataSources"/>.
+        /// </summary>
+        /// <param name="endpointDataSources">An collection of <see cref="EndpointDataSource" /> objects.</param>
+        /// <returns>A <see cref="CompositeEndpointDataSource"/> </returns>
         public CompositeEndpointDataSource(IEnumerable<EndpointDataSource> endpointDataSources) : this()
         {
             _dataSources = new List<EndpointDataSource>();
@@ -62,6 +67,9 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
+        /// <summary>
+        /// Returns the collection of <see cref="EndpointDataSource"/> instances associated with the object.
+        /// </summary>
         public IEnumerable<EndpointDataSource> DataSources => _dataSources;
 
         /// <summary>
@@ -123,12 +131,12 @@ namespace Microsoft.AspNetCore.Routing
                 // Refresh the endpoints from datasource so that callbacks can get the latest endpoints
                 _endpoints = _dataSources.SelectMany(d => d.Endpoints).ToArray();
 
-                // Prevent consumers from re-registering callback to inflight events as that can 
+                // Prevent consumers from re-registering callback to inflight events as that can
                 // cause a stackoverflow
                 // Example:
                 // 1. B registers A
                 // 2. A fires event causing B's callback to get called
-                // 3. B executes some code in its callback, but needs to re-register callback 
+                // 3. B executes some code in its callback, but needs to re-register callback
                 //    in the same callback
                 var oldTokenSource = _cts;
                 var oldToken = _consumerChangeToken;

src/Http/Routing/src/Constraints/OptionalRouteConstraint.cs

@@ -7,10 +7,14 @@ using Microsoft.AspNetCore.Http;
 namespace Microsoft.AspNetCore.Routing.Constraints
 {
     /// <summary>
-    /// Defines a constraint on an optional parameter. If the parameter is present, then it is constrained by InnerConstraint. 
+    /// Defines a constraint on an optional parameter. If the parameter is present, then it is constrained by InnerConstraint.
     /// </summary>
     public class OptionalRouteConstraint : IRouteConstraint
     {
+        /// <summary>
+        /// Creates a new <see cref="OptionalRouteConstraint"/> instance given the <paramref name="innerConstraint"/>.
+        /// </summary>
+        /// <param name="innerConstraint"></param>
         public OptionalRouteConstraint(IRouteConstraint innerConstraint)
         {
             if (innerConstraint == null)
@@ -21,8 +25,12 @@ namespace Microsoft.AspNetCore.Routing.Constraints
             InnerConstraint = innerConstraint;
         }
 
+        /// <summary>
+        /// Gets the <see cref="IRouteConstraint"/> associated with the optional parameter.
+        /// </summary>
         public IRouteConstraint InnerConstraint { get; }
 
+        /// <inheritdoc />
         public bool Match(
             HttpContext? httpContext,
             IRouter? route,

src/Http/Routing/src/Constraints/RegexRouteConstraint.cs

@@ -8,10 +8,17 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing.Constraints
 {
+    /// <summary>
+    /// Constrains a route parameter to match a regular expression.
+    /// </summary>
     public class RegexRouteConstraint : IRouteConstraint
     {
         private static readonly TimeSpan RegexMatchTimeout = TimeSpan.FromSeconds(10);
 
+        /// <summary>
+        /// Constructor for a <see cref="RegexRouteConstraint"/> given a <paramref name="regex"/>.
+        /// </summary>
+        /// <param name="regex">A <see cref="Regex"/> instance to use as a constraint.</param>
         public RegexRouteConstraint(Regex regex)
         {
             if (regex == null)
@@ -22,6 +29,10 @@ namespace Microsoft.AspNetCore.Routing.Constraints
             Constraint = regex;
         }
 
+        /// <summary>
+        /// Constructor for a <see cref="RegexRouteConstraint"/> given a <paramref name="regexPattern"/>.
+        /// </summary>
+        /// <param name="regexPattern">A string containing the regex pattern.</param>
         public RegexRouteConstraint(string regexPattern)
         {
             if (regexPattern == null)
@@ -35,8 +46,12 @@ namespace Microsoft.AspNetCore.Routing.Constraints
                 RegexMatchTimeout);
         }
 
+        /// <summary>
+        /// Gets the regular expression used in the route constraint.
+        /// </summary>
         public Regex Constraint { get; private set; }
 
+        /// <inheritdoc />
         public bool Match(
             HttpContext? httpContext,
             IRouter? route,

src/Http/Routing/src/DataTokensMetadata.cs

@@ -14,6 +14,10 @@ namespace Microsoft.AspNetCore.Routing
     /// </summary>
     public sealed class DataTokensMetadata : IDataTokensMetadata
     {
+        /// <summary>
+        /// Constructor for a new <see cref="DataTokensMetadata"/> given <paramref name="dataTokens"/>.
+        /// </summary>
+        /// <param name="dataTokens">The data tokens.</param>
         public DataTokensMetadata(IReadOnlyDictionary<string, object> dataTokens)
         {
             if (dataTokens == null)

src/Http/Routing/src/INamedRouter.cs

@@ -3,8 +3,14 @@
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// An interface for an <see cref="IRouter"/> with a name.
+    /// </summary>
     public interface INamedRouter : IRouter
     {
+        /// <summary>
+        /// The name of the router. Can be null.
+        /// </summary>
         string? Name { get; }
     }
 }

src/Http/Routing/src/IRouteCollection.cs

@@ -3,8 +3,15 @@
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Interface for a router that supports appending new routes.
+    /// </summary>
     public interface IRouteCollection : IRouter
     {
+        /// <summary>
+        /// Appends the collection of routes defined in <paramref name="router"/>.
+        /// </summary>
+        /// <param name="router">A <see cref="IRouter"/> instance.</param>
         void Add(IRouter router);
     }
 }

src/Http/Routing/src/InlineRouteParameterParser.cs

@@ -7,8 +7,16 @@ using Microsoft.AspNetCore.Routing.Template;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Contains methods for parsing processing constraints from a route definition.
+    /// </summary>
     public static class InlineRouteParameterParser
     {
+        /// <summary>
+        /// Parses a string representing the provided <paramref name="routeParameter"/> into a <see cref="TemplatePart"/>.
+        /// </summary>
+        /// <param name="routeParameter">A string representation of the route parameter.</param>
+        /// <returns>A <see cref="TemplatePart"/> instance.</returns>
         public static TemplatePart ParseRouteParameter(string routeParameter)
         {
             if (routeParameter == null)

src/Http/Routing/src/Internal/DfaGraphWriter.cs

@@ -26,11 +26,20 @@ namespace Microsoft.AspNetCore.Routing.Internal
     {
         private readonly IServiceProvider _services;
 
+        /// <summary>
+        /// Constructor for a <see cref="DfaGraphWriter"/> given <paramref name="services"/>.
+        /// </summary>
+        /// <param name="services">The <see cref="IServiceCollection" /> to add services to.</param>
         public DfaGraphWriter(IServiceProvider services)
         {
             _services = services;
         }
 
+        /// <summary>
+        /// Displays a graph representation of <paramref name="dataSource"/> in DOT.
+        /// </summary>
+        /// <param name="dataSource">The <see cref="EndpointDataSource"/> to extract routes from.</param>
+        /// <param name="writer">The <see cref="TextWriter"/> to which the content is written.</param>
         public void Write(EndpointDataSource dataSource, TextWriter writer)
         {
             var builder = _services.GetRequiredService<DfaMatcherBuilder>();
@@ -46,7 +55,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
 
             // Assign each node a sequential index.
             var visited = new Dictionary<DfaNode, int>();
-            
+
             var tree = builder.BuildDfaTree(includeLabel: true);
 
             writer.WriteLine("digraph DFA {");

src/Http/Routing/src/Matching/EndpointMetadataComparer.cs

@@ -87,6 +87,9 @@ namespace Microsoft.AspNetCore.Routing.Matching
     /// </typeparam>
     public abstract class EndpointMetadataComparer<TMetadata> : IComparer<Endpoint> where TMetadata : class
     {
+        /// <summary>
+        /// A default instance of the <see cref="EndpointMetadataComparer"/>.
+        /// </summary>
         public static readonly EndpointMetadataComparer<TMetadata> Default = new DefaultComparer<TMetadata>();
 
         /// <summary>

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

@@ -19,8 +19,10 @@ namespace Microsoft.AspNetCore.Routing.Matching
         private const string WildcardPrefix = "*.";
 
         // Run after HTTP methods, but before 'default'.
+        /// <inheritdoc />
         public override int Order { get; } = -100;
 
+        /// <inheritdoc />
         public IComparer<Endpoint> Comparer { get; } = new HostMetadataEndpointComparer();
 
         bool INodeBuilderPolicy.AppliesToEndpoints(IReadOnlyList<Endpoint> endpoints)
@@ -70,6 +72,7 @@ namespace Microsoft.AspNetCore.Routing.Matching
             });
         }
 
+        /// <inheritdoc />
         public Task ApplyAsync(HttpContext httpContext, CandidateSet candidates)
         {
             if (httpContext == null)
@@ -189,6 +192,7 @@ namespace Microsoft.AspNetCore.Routing.Matching
             throw new InvalidOperationException($"Could not parse host: {host}");
         }
 
+        /// <inheritdoc />
         public IReadOnlyList<PolicyNodeEdge> GetEdges(IReadOnlyList<Endpoint> endpoints)
         {
             if (endpoints == null)
@@ -273,6 +277,7 @@ namespace Microsoft.AspNetCore.Routing.Matching
                 .ToArray();
         }
 
+        /// <inheritdoc />
         public PolicyJumpTable BuildJumpTable(int exitDestination, IReadOnlyList<PolicyJumpTableEdge> edges)
         {
             if (edges == null)

src/Http/Routing/src/Matching/INodeBuilderPolicy.cs

@@ -6,12 +6,31 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing.Matching
 {
+    /// <summary>
+    /// Implements an interface for a matcher policy with support for generating graph representations of the endpoints.
+    /// </summary>
     public interface INodeBuilderPolicy
     {
+        /// <summary>
+        /// Evaluates if the policy matches any of the endpoints provided in <paramref name="endpoints"/>.
+        /// </summary>
+        /// <param name="endpoints">A list of <see cref="Endpoint"/>.</param>
+        /// <returns><see langword="true"/> if the policy applies to any of the provided <paramref name="endpoints"/>.</returns>
         bool AppliesToEndpoints(IReadOnlyList<Endpoint> endpoints);
 
+        /// <summary>
+        /// Generates a graph that representations the relationship between endpoints and hosts.
+        /// </summary>
+        /// <param name="endpoints">A list of <see cref="Endpoint"/>.</param>
+        /// <returns>A graph representing the relationship between endpoints and hosts.</returns>
         IReadOnlyList<PolicyNodeEdge> GetEdges(IReadOnlyList<Endpoint> endpoints);
 
+        /// <summary>
+        /// Constructs a jump table given the a set of <paramref name="edges"/>.
+        /// </summary>
+        /// <param name="exitDestination">The default destination for lookups.</param>
+        /// <param name="edges">A list of <see cref="PolicyJumpTableEdge"/>.</param>
+        /// <returns>A <see cref="PolicyJumpTable"/> instance.</returns>
         PolicyJumpTable BuildJumpTable(int exitDestination, IReadOnlyList<PolicyJumpTableEdge> edges);
     }
 }

src/Http/Routing/src/Matching/PolicyJumpTable.cs

@@ -5,8 +5,15 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing.Matching
 {
+    /// <summary>
+    /// Supports retrieving endpoints that fulfill a certain matcher policy.
+    /// </summary>
     public abstract class PolicyJumpTable
     {
+        /// <summary>
+        /// Returns the destination for a given <paramref name="httpContext"/> in the current jump table.
+        /// </summary>
+        /// <param name="httpContext">The <see cref="HttpContext"/> associated with the current request.</param>
         public abstract int GetDestination(HttpContext httpContext);
 
         internal virtual string DebuggerToString()

src/Http/Routing/src/Matching/PolicyJumpTableEdge.cs

@@ -3,16 +3,31 @@
 
 namespace Microsoft.AspNetCore.Routing.Matching
 {
+    /// <summary>
+    /// Represents an entry in a <see cref="PolicyJumpTable"/>.
+    /// </summary>
     public readonly struct PolicyJumpTableEdge
     {
+        /// <summary>
+        /// Constructs a new <see cref="PolicyJumpTableEdge"/> instance.
+        /// </summary>
+        /// <param name="state">Represents the match heuristic of the policy.</param>
+        /// <param name="destination"></param>
         public PolicyJumpTableEdge(object state, int destination)
         {
             State = state ?? throw new System.ArgumentNullException(nameof(state));
             Destination = destination;
         }
 
+        /// <summary>
+        /// Gets the object used to represent the match heuristic. Can be a host, HTTP method, etc.
+        /// depending on the matcher policy.
+        /// </summary>
         public object State { get; }
 
+        /// <summary>
+        /// Gets the destination of the current entry.
+        /// </summary>
         public int Destination { get; }
     }
 }

src/Http/Routing/src/Matching/PolicyNodeEdge.cs

@@ -6,16 +6,31 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing.Matching
 {
+    /// <summary>
+    /// Represents an edge in a matcher policy graph.
+    /// </summary>
     public readonly struct PolicyNodeEdge
     {
+        /// <summary>
+        /// Constructs a new <see cref="PolicyNodeEdge"/> instance.
+        /// </summary>
+        /// <param name="state">Represents the match heuristic of the policy.</param>
+        /// <param name="endpoints">Represents the endpoints that match the policy</param>
         public PolicyNodeEdge(object state, IReadOnlyList<Endpoint> endpoints)
         {
             State = state ?? throw new System.ArgumentNullException(nameof(state));
             Endpoints = endpoints ?? throw new System.ArgumentNullException(nameof(endpoints));
         }
 
+        /// <summary>
+        /// Gets the endpoints that match the policy defined by <see cref="State"/>.
+        /// </summary>
         public IReadOnlyList<Endpoint> Endpoints { get; }
 
+        /// <summary>
+        /// Gets the object used to represent the match heuristic. Can be a host, HTTP method, etc.
+        /// depending on the matcher policy.
+        /// </summary>
         public object State { get; }
     }
 }

src/Http/Routing/src/Microsoft.AspNetCore.Routing.csproj

@@ -7,7 +7,7 @@ Microsoft.AspNetCore.Routing.Route
 Microsoft.AspNetCore.Routing.RouteCollection</Description>
     <TargetFramework>$(DefaultNetCoreTargetFramework)</TargetFramework>
     <IsAspNetCoreApp>true</IsAspNetCoreApp>
-    <NoWarn>$(NoWarn);CS1591</NoWarn>
+    <NoWarn>$(NoWarn.Replace('1591', ''))</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;routing</PackageTags>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

src/Http/Routing/src/RequestDelegateRouteBuilderExtensions.cs

@@ -10,6 +10,9 @@ using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Provides extension methods for adding new handlers to a <see cref="IRouteBuilder"/>.
+    /// </summary>
     public static class RequestDelegateRouteBuilderExtensions
     {
         /// <summary>

src/Http/Routing/src/Route.cs

@@ -7,10 +7,19 @@ using System.Threading.Tasks;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Represents an instance of a route.
+    /// </summary>
     public class Route : RouteBase
     {
         private readonly IRouter _target;
 
+        /// <summary>
+        /// Constructs a new <see cref="Route"/> instance.
+        /// </summary>
+        /// <param name="target">An <see cref="IRouter"/> instance associated with the component.</param>
+        /// <param name="routeTemplate">A string representation of the route template.</param>
+        /// <param name="inlineConstraintResolver">An <see cref="IInlineConstraintResolver"/> used for resolving inline constraints.</param>
         public Route(
             IRouter target,
             string routeTemplate,
@@ -25,6 +34,15 @@ namespace Microsoft.AspNetCore.Routing
         {
         }
 
+        /// <summary>
+        /// Constructs a new <see cref="Route"/> instance.
+        /// </summary>
+        /// <param name="target">An <see cref="IRouter"/> instance associated with the component.</param>
+        /// <param name="routeTemplate">A string representation of the route template.</param>
+        /// <param name="defaults">The default values for parameters in the route.</param>
+        /// <param name="constraints">The constraints for the route.</param>
+        /// <param name="dataTokens">The data tokens for the route.</param>
+        /// <param name="inlineConstraintResolver">An <see cref="IInlineConstraintResolver"/> used for resolving inline constraints.</param>
         public Route(
             IRouter target,
             string routeTemplate,
@@ -36,6 +54,16 @@ namespace Microsoft.AspNetCore.Routing
         {
         }
 
+        /// <summary>
+        /// Constructs a new <see cref="Route"/> instance.
+        /// </summary>
+        /// <param name="target">An <see cref="IRouter"/> instance associated with the component.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeTemplate">A string representation of the route template.</param>
+        /// <param name="defaults">The default values for parameters in the route.</param>
+        /// <param name="constraints">The constraints for the route.</param>
+        /// <param name="dataTokens">The data tokens for the route.</param>
+        /// <param name="inlineConstraintResolver">An <see cref="IInlineConstraintResolver"/> used for resolving inline constraints.</param>
         public Route(
             IRouter target,
             string? routeName,
@@ -45,11 +73,11 @@ namespace Microsoft.AspNetCore.Routing
             RouteValueDictionary? dataTokens,
             IInlineConstraintResolver inlineConstraintResolver)
             : base(
-                  routeTemplate, 
+                  routeTemplate,
-                  routeName, 
+                  routeName,
-                  inlineConstraintResolver, 
+                  inlineConstraintResolver,
-                  defaults, 
+                  defaults,
-                  constraints, 
+                  constraints,
                   dataTokens)
         {
             if (target == null)
@@ -60,14 +88,19 @@ namespace Microsoft.AspNetCore.Routing
             _target = target;
         }
 
+        /// <summary>
+        /// Gets a string representation of the route template.
+        /// </summary>
         public string? RouteTemplate => ParsedTemplate.TemplateText;
 
+        /// <inheritdoc />
         protected override Task OnRouteMatched(RouteContext context)
         {
             context.RouteData.Routers.Add(_target);
             return _target.RouteAsync(context);
         }
 
+        /// <inheritdoc />
         protected override VirtualPathData? OnVirtualPathGenerated(VirtualPathContext context)
         {
             return _target.GetVirtualPath(context);

src/Http/Routing/src/RouteBase.cs

@@ -14,6 +14,9 @@ using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Base class implementation of an <see cref="IRouter"/>.
+    /// </summary>
     public abstract class RouteBase : IRouter, INamedRouter
     {
         private readonly object _loggersLock = new object();
@@ -23,6 +26,15 @@ namespace Microsoft.AspNetCore.Routing
         private ILogger? _logger;
         private ILogger? _constraintLogger;
 
+        /// <summary>
+        /// Creates a new <see cref="RouteBase"/> instance.
+        /// </summary>
+        /// <param name="template">The route template.</param>
+        /// <param name="name">The name of the route.</param>
+        /// <param name="constraintResolver">An <see cref="IInlineConstraintResolver"/> used for resolving inline constraints.</param>
+        /// <param name="defaults">The default values for parameters in the route.</param>
+        /// <param name="constraints">The constraints for the route.</param>
+        /// <param name="dataTokens">The data tokens for the route.</param>
         public RouteBase(
             string? template,
             string? name,
@@ -56,20 +68,45 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
+        /// <summary>
+        /// Gets the set of constraints associated with each route.
+        /// </summary>
         public virtual IDictionary<string, IRouteConstraint> Constraints { get; protected set; }
 
+        /// <summary>
+        /// Gets the resolver used for resolving inline constraints.
+        /// </summary>
         protected virtual IInlineConstraintResolver ConstraintResolver { get; set; }
 
+        /// <summary>
+        /// Gets the data tokens associated with the route.
+        /// </summary>
         public virtual RouteValueDictionary DataTokens { get; protected set; }
 
+        /// <summary>
+        /// Gets the default values for each route parameter.
+        /// </summary>
         public virtual RouteValueDictionary Defaults { get; protected set; }
 
+        /// <inheritdoc />
         public virtual string? Name { get; protected set; }
 
+        /// <summary>
+        /// Gets the <see cref="RouteTemplate"/> associated with the route.
+        /// </summary>
         public virtual RouteTemplate ParsedTemplate { get; protected set; }
 
+        /// <summary>
+        /// Executes asynchronously whenever routing occurs.
+        /// </summary>
+        /// <param name="context">A <see cref="RouteContext"/> instance.</param>
         protected abstract Task OnRouteMatched(RouteContext context);
 
+        /// <summary>
+        /// Executes whenever a virtual path is dervied from a <paramref name="context"/>.
+        /// </summary>
+        /// <param name="context">A <see cref="VirtualPathContext"/> instance.</param>
+        /// <returns>A <see cref="VirtualPathData"/> instance.</returns>
         protected abstract VirtualPathData? OnVirtualPathGenerated(VirtualPathContext context);
 
         /// <inheritdoc />
@@ -168,6 +205,12 @@ namespace Microsoft.AspNetCore.Routing
             return pathData;
         }
 
+        /// <summary>
+        /// Extracts constatins from a given <see cref="RouteTemplate"/>.
+        /// </summary>
+        /// <param name="inlineConstraintResolver">An <see cref="IInlineConstraintResolver"/> used for resolving inline constraints.</param>
+        /// <param name="parsedTemplate">A <see cref="RouteTemplate"/> instance.</param>
+        /// <param name="constraints">A collection of constraints on the route template.</param>
         protected static IDictionary<string, IRouteConstraint> GetConstraints(
             IInlineConstraintResolver inlineConstraintResolver,
             RouteTemplate parsedTemplate,
@@ -199,6 +242,11 @@ namespace Microsoft.AspNetCore.Routing
             return constraintBuilder.Build();
         }
 
+        /// <summary>
+        /// Gets the default values for parameters in a templates.
+        /// </summary>
+        /// <param name="parsedTemplate">A <see cref="RouteTemplate"/> instance.</param>
+        /// <param name="defaults">A collection of defaults for each parameter.</param>
         protected static RouteValueDictionary GetDefaults(
             RouteTemplate parsedTemplate,
             RouteValueDictionary? defaults)
@@ -296,6 +344,7 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
+        /// <inheritdoc />
         public override string ToString()
         {
             return ParsedTemplate.TemplateText!;

src/Http/Routing/src/RouteBuilder.cs

@@ -10,13 +10,26 @@ using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Provides support for specifying routes in an application.
+    /// </summary>
     public class RouteBuilder : IRouteBuilder
     {
+        /// <summary>
+        /// Constructs a new <see cref="RouteBuilder"/> instance given an <paramref name="applicationBuilder"/>.
+        /// </summary>
+        /// <param name="applicationBuilder">An <see cref="IApplicationBuilder"/> instance.</param>
         public RouteBuilder(IApplicationBuilder applicationBuilder)
             : this(applicationBuilder, defaultHandler: null)
         {
         }
 
+        /// <summary>
+        /// Constructs a new <see cref="RouteBuilder"/> instance given an <paramref name="applicationBuilder"/>
+        /// and <paramref name="defaultHandler"/>.
+        /// </summary>
+        /// <param name="applicationBuilder">An <see cref="IApplicationBuilder"/> instance.</param>
+        /// <param name="defaultHandler">The default <see cref="IRouter"/> used if a new route is added without a handler.</param>
         public RouteBuilder(IApplicationBuilder applicationBuilder, IRouter? defaultHandler)
         {
             if (applicationBuilder == null)
@@ -39,14 +52,19 @@ namespace Microsoft.AspNetCore.Routing
             Routes = new List<IRouter>();
         }
 
+        /// <inheritdoc />
         public IApplicationBuilder ApplicationBuilder { get; }
 
+        /// <inheritdoc />
         public IRouter? DefaultHandler { get; set; }
 
+        /// <inheritdoc />
         public IServiceProvider ServiceProvider { get; }
 
+        /// <inheritdoc />
         public IList<IRouter> Routes { get; }
 
+        /// <inheritdoc />
         public IRouter Build()
         {
             var routeCollection = new RouteCollection();

src/Http/Routing/src/RouteCollection.cs

@@ -14,6 +14,9 @@ using Microsoft.Extensions.Options;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Supports managing a collection fo multiple routes.
+    /// </summary>
     public class RouteCollection : IRouteCollection
     {
         private readonly static char[] UrlQueryDelimiters = new char[] { '?', '#' };
@@ -24,16 +27,24 @@ namespace Microsoft.AspNetCore.Routing
 
         private RouteOptions? _options;
 
+        /// <summary>
+        /// Gets the route at a given index.
+        /// </summary>
+        /// <value>The route at the given index.</value>
         public IRouter this[int index]
         {
             get { return _routes[index]; }
         }
 
+        /// <summary>
+        /// Gets the total number of routes registered in the collection.
+        /// </summary>
         public int Count
         {
             get { return _routes.Count; }
         }
 
+        /// <inheritdoc />
         public void Add(IRouter router)
         {
             if (router == null)
@@ -57,6 +68,7 @@ namespace Microsoft.AspNetCore.Routing
             _routes.Add(router);
         }
 
+        /// <inheritdoc />
         public async virtual Task RouteAsync(RouteContext context)
         {
             // Perf: We want to avoid allocating a new RouteData for each route we need to process.
@@ -88,6 +100,7 @@ namespace Microsoft.AspNetCore.Routing
             }
         }
 
+        /// <inheritdoc />
         public virtual VirtualPathData? GetVirtualPath(VirtualPathContext context)
         {
             EnsureOptions(context.HttpContext);

src/Http/Routing/src/RouteConstraintMatcher.cs

@@ -9,8 +9,24 @@ using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Use to evaluate if all route parameter values match their constraints.
+    /// </summary>
     public static class RouteConstraintMatcher
     {
+        /// <summary>
+        /// Determines if <paramref name="routeValues"/> match the provided <paramref name="constraints"/>.
+        /// </summary>
+        /// <param name="constraints">The constraints for the route.</param>
+        /// <param name="routeValues">The route parameter values extracted from the matched route.</param>
+        /// <param name="httpContext">The <see cref="HttpContext"/> associated with the current request.</param>
+        /// <param name="route">The router that this constraint belongs to.</param>
+        /// <param name="routeDirection">
+        /// Indicates whether the constraint check is performed
+        /// when the incoming request is handled or when a URL is generated.
+        /// </param>
+        /// <param name="logger">The <see cref="ILogger{TCategoryName}"/>.</param>
+        /// <returns><see langword="true"/> if the all route values match their constraints.</returns>
         public static bool Match(
             IDictionary<string, IRouteConstraint> constraints,
             RouteValueDictionary routeValues,

src/Http/Routing/src/RouteEndpointBuilder.cs

@@ -8,12 +8,27 @@ using Microsoft.AspNetCore.Routing.Patterns;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Supports building a new <see cref="RouteEndpoint"/>.
+    /// </summary>
     public sealed class RouteEndpointBuilder : EndpointBuilder
     {
+        /// <summary>
+        /// Gets or sets the <see cref="RoutePattern"/> associated with this endpoint.
+        /// </summary>
         public RoutePattern RoutePattern { get; set; }
 
+        /// <summary>
+        ///  Gets or sets the order assigned to the endpoint.
+        /// </summary>
         public int Order { get; set; }
 
+        /// <summary>
+        /// Constructs a new <see cref="RouteEndpointBuilder"/> instance.
+        /// </summary>
+        /// <param name="requestDelegate">The delegate used to process requests for the endpoint.</param>
+        /// <param name="routePattern">The <see cref="RoutePattern"/> to use in URL matching.</param>
+        /// <param name="order">The order assigned to the endpoint.</param>
         public RouteEndpointBuilder(
            RequestDelegate requestDelegate,
            RoutePattern routePattern,
@@ -24,6 +39,7 @@ namespace Microsoft.AspNetCore.Routing
             Order = order;
         }
 
+        /// <inheritdoc />
         public override Endpoint Build()
         {
             if (RequestDelegate is null)

src/Http/Routing/src/RouteHandler.cs

@@ -8,26 +8,36 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Supports implementing a handler that executes for a given route.
+    /// </summary>
     public class RouteHandler : IRouteHandler, IRouter
     {
         private readonly RequestDelegate _requestDelegate;
 
+        /// <summary>
+        /// Constructs a new <see cref="RouteHandler"/> instance.
+        /// </summary>
+        /// <param name="requestDelegate">The delegate used to process requests.</param>
         public RouteHandler(RequestDelegate requestDelegate)
         {
             _requestDelegate = requestDelegate;
         }
 
+        /// <inheritdoc />
         public RequestDelegate GetRequestHandler(HttpContext httpContext, RouteData routeData)
         {
             return _requestDelegate;
         }
 
+        /// <inheritdoc />
         public VirtualPathData? GetVirtualPath(VirtualPathContext context)
         {
             // Nothing to do.
             return null;
         }
 
+        /// <inheritdoc />
         public Task RouteAsync(RouteContext context)
         {
             context.Handler = _requestDelegate;

src/Http/Routing/src/RouteOptions.cs

@@ -9,6 +9,9 @@ using Microsoft.AspNetCore.Routing.Constraints;
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// Represents the configurable options on a route.
+    /// </summary>
     public class RouteOptions
     {
         private IDictionary<string, Type> _constraintTypeMap = GetDefaultConstraintMap();
@@ -64,6 +67,9 @@ namespace Microsoft.AspNetCore.Routing
         /// </remarks>
         public bool SuppressCheckForUnhandledSecurityMetadata { get; set; }
 
+        /// <summary>
+        /// Gets or sets a collection of constraints on the current route.
+        /// </summary>
         public IDictionary<string, Type> ConstraintMap
         {
             get

src/Http/Routing/src/RouteValueEqualityComparer.cs

@@ -20,6 +20,9 @@ namespace Microsoft.AspNetCore.Routing
     /// </remarks>
     public class RouteValueEqualityComparer : IEqualityComparer<object?>
     {
+        /// <summary>
+        /// A default instance of the <see cref="RouteValueEqualityComparer"/>.
+        /// </summary>
         public static readonly RouteValueEqualityComparer Default = new RouteValueEqualityComparer();
 
         /// <inheritdoc />

src/Http/Routing/src/RouterMiddleware.cs

@@ -9,12 +9,21 @@ using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Builder
 {
+    /// <summary>
+    /// Middleware responsible for routing.
+    /// </summary>
     public class RouterMiddleware
     {
         private readonly ILogger _logger;
         private readonly RequestDelegate _next;
         private readonly IRouter _router;
 
+        /// <summary>
+        /// Constructs a new <see cref="RouterMiddleware"/> instance with a given <paramref name="router"/>.
+        /// </summary>
+        /// <param name="next">The delegate representing the remaining middleware in the request pipeline.</param>
+        /// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
+        /// <param name="router">The <see cref="IRouter"/> to use for routing requests.</param>
         public RouterMiddleware(
             RequestDelegate next,
             ILoggerFactory loggerFactory,
@@ -26,6 +35,11 @@ namespace Microsoft.AspNetCore.Builder
             _logger = loggerFactory.CreateLogger<RouterMiddleware>();
         }
 
+        /// <summary>
+        /// Evaluates the handler associated with the <see cref="RouteContext"/>
+        /// derived from <paramref name="httpContext"/>.
+        /// </summary>
+        /// <param name="httpContext">A <see cref="HttpContext"/> instance.</param>
         public async Task Invoke(HttpContext httpContext)
         {
             var context = new RouteContext(httpContext);

src/Http/Routing/src/RoutingFeature.cs

@@ -3,8 +3,12 @@
 
 namespace Microsoft.AspNetCore.Routing
 {
+    /// <summary>
+    /// A feature for routing functionality.
+    /// </summary>
     public class RoutingFeature : IRoutingFeature
     {
+        /// <inheritdoc />
         public RouteData? RouteData { get; set; }
     }
 }

src/Http/Routing/src/Template/InlineConstraint.cs

@@ -25,6 +25,10 @@ namespace Microsoft.AspNetCore.Routing.Template
             Constraint = constraint;
         }
 
+        /// <summary>
+        /// Creates a new <see cref="InlineConstraint"/> instance given a <see cref="RoutePatternParameterPolicyReference"/>.
+        /// </summary>
+        /// <param name="other">A <see cref="RoutePatternParameterPolicyReference"/> instance.</param>
         public InlineConstraint(RoutePatternParameterPolicyReference other)
         {
             if (other == null)

src/Http/Routing/src/Template/RoutePrecedence.cs

@@ -15,11 +15,17 @@ namespace Microsoft.AspNetCore.Routing.Template
     /// </summary>
     public static class RoutePrecedence
     {
-        // Compute the precedence for matching a provided url
+        /// <summary>
-        // e.g.: /api/template == 1.1
+        ///  Compute the precedence for matching a provided url
-        //       /api/template/{id} == 1.13
+        /// </summary>
-        //       /api/{id:int} == 1.2
+        /// <example>
-        //       /api/template/{id:int} == 1.12
+        ///     e.g.: /api/template == 1.1
+        ///     /api/template/{id} == 1.13
+        ///     /api/{id:int} == 1.2
+        ///     /api/template/{id:int} == 1.12
+        /// </example>
+        /// <param name="template">The <see cref="RouteTemplate"/> to compute precendence for.</param>
+        /// <returns>A <see cref="decimal"/> representing the route's precendence.</returns>
         public static decimal ComputeInbound(RouteTemplate template)
         {
             ValidateSegementLength(template.Segments.Count);
@@ -61,11 +67,17 @@ namespace Microsoft.AspNetCore.Routing.Template
             return precedence;
         }
 
-        // Compute the precedence for generating a url
+        /// <summary>
-        // e.g.: /api/template          == 5.5
+        ///  Compute the precedence for generating a url.
-        //       /api/template/{id}     == 5.53
+        /// </summary>
-        //       /api/{id:int}          == 5.4
+        /// <example>
-        //       /api/template/{id:int} == 5.54
+        ///     e.g.: /api/template    == 5.5
+        ///     /api/template/{id}     == 5.53
+        ///     /api/{id:int}          == 5.4
+        ///     /api/template/{id:int} == 5.54
+        /// </example>
+        /// <param name="template">The <see cref="RouteTemplate"/> to compute precendence for.</param>
+        /// <returns>A <see cref="decimal"/> representing the route's precendence.</returns>
         public static decimal ComputeOutbound(RouteTemplate template)
         {
             ValidateSegementLength(template.Segments.Count);

src/Http/Routing/src/Template/RouteTemplate.cs

@@ -11,11 +11,18 @@ using Microsoft.AspNetCore.Routing.Patterns;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Represents the template for a route.
+    /// </summary>
     [DebuggerDisplay("{DebuggerToString()}")]
     public class RouteTemplate
     {
         private const string SeparatorString = "/";
 
+        /// <summary>
+        /// Constructs a new <see cref="RouteTemplate"/> instance given <paramref name="other"/>.
+        /// </summary>
+        /// <param name="other">A <see cref="RoutePattern"/> instance.</param>
         public RouteTemplate(RoutePattern other)
         {
             if (other == null)
@@ -42,6 +49,12 @@ namespace Microsoft.AspNetCore.Routing.Template
             }
         }
 
+        /// <summary>
+        /// Constructs a a new <see cref="RouteTemplate" /> instance given the <paramref name="template"/> string
+        /// and a list of <paramref name="segments"/>. Computes the parameters in the route template.
+        /// </summary>
+        /// <param name="template">A string representation of the route template.</param>
+        /// <param name="segments">A list of <see cref="TemplateSegment"/>.</param>
         public RouteTemplate(string template, List<TemplateSegment> segments)
         {
             if (segments == null)
@@ -68,12 +81,26 @@ namespace Microsoft.AspNetCore.Routing.Template
             }
         }
 
+        /// <summary>
+        /// Gets the string representation of the route template.
+        /// </summary>
         public string? TemplateText { get; }
 
+        /// <summary>
+        /// Gets the list of <see cref="TemplatePart"/> that represent that parameters defined in the route template.
+        /// </summary>
         public IList<TemplatePart> Parameters { get; }
 
+        /// <summary>
+        /// Gets the list of <see cref="TemplateSegment"/> that compromise the route template.
+        /// </summary>
         public IList<TemplateSegment> Segments { get; }
 
+        /// <summary>
+        /// Gets the <see cref="TemplateSegment"/> at a given index.
+        /// </summary>
+        /// <param name="index">The index of the element to retrieve.</param>
+        /// <returns>A <see cref="TemplateSegment"/> instance.</returns>
         public TemplateSegment? GetSegment(int index)
         {
             if (index < 0)
@@ -109,7 +136,7 @@ namespace Microsoft.AspNetCore.Routing.Template
         }
 
         /// <summary>
-        /// Converts the <see cref="RouteTemplate"/> to the equivalent 
+        /// Converts the <see cref="RouteTemplate"/> to the equivalent
         /// <see cref="RoutePattern"/>
         /// </summary>
         /// <returns>A <see cref="RoutePattern"/>.</returns>

src/Http/Routing/src/Template/TemplateBinder.cs

@@ -15,6 +15,9 @@ using Microsoft.Extensions.ObjectPool;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Supports processing and binding parameter values in a route template.
+    /// </summary>
     public class TemplateBinder
     {
         private readonly UrlEncoder _urlEncoder;
@@ -159,7 +162,12 @@ namespace Microsoft.AspNetCore.Routing.Template
             _slots = AssignSlots(_pattern, _filters);
         }
 
-        // Step 1: Get the list of values we're going to try to use to match and generate this URI
+        /// <summary>
+        /// Generates the parameter values in the route.
+        /// </summary>
+        /// <param name="ambientValues">The values associated with the current request.</param>
+        /// <param name="values">The route values to process.</param>
+        /// <returns>A <see cref="TemplateValuesResult"/> instance. Can be null.</returns>
         public TemplateValuesResult? GetValues(RouteValueDictionary? ambientValues, RouteValueDictionary values)
         {
             // Make a new copy of the slots array, we'll use this as 'scratch' space
@@ -424,10 +432,14 @@ namespace Microsoft.AspNetCore.Routing.Template
         }
 
         // Step 1.5: Process constraints
-        //
+        /// <summary>
-        // Processes the constraints **if** they were passed in to the TemplateBinder constructor.
+        /// Processes the constraints **if** they were passed in to the TemplateBinder constructor.
-        // Returns true on success
+        /// </summary>
-        // Returns false + sets the name/constraint for logging on failure.
+        /// <param name="httpContext">The <see cref="HttpContext"/> associated with the current request.</param>
+        /// <param name="combinedValues">A dictionary that contains the parameters for the route.</param>
+        /// <param name="parameterName">The name of the parameter.</param>
+        /// <param name="constraint">The constraint object.</param>
+        /// <returns><see langword="true"/> if constraints were processed succesfully and false otherwise.</returns>
         public bool TryProcessConstraints(HttpContext? httpContext, RouteValueDictionary combinedValues, out string? parameterName, out IRouteConstraint? constraint)
         {
             var constraints = _constraints;
@@ -447,6 +459,11 @@ namespace Microsoft.AspNetCore.Routing.Template
         }
 
         // Step 2: If the route is a match generate the appropriate URI
+        /// <summary>
+        /// Returns a string representation of the URI associated with the route.
+        /// </summary>
+        /// <param name="acceptedValues">A dictionary that contains the parameters for the route.</param>
+        /// <returns>The string representation of the route.</returns>
         public string? BindValues(RouteValueDictionary acceptedValues)
         {
             var context = _pool.Get();

src/Http/Routing/src/Template/TemplateMatcher.cs

@@ -9,6 +9,9 @@ using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Supports matching paths to route templates and extracting parameter values.
+    /// </summary>
     public class TemplateMatcher
     {
         private const string SeparatorString = "/";
@@ -21,6 +24,11 @@ namespace Microsoft.AspNetCore.Routing.Template
         private static readonly char[] Delimiters = new char[] { SeparatorChar };
         private RoutePatternMatcher _routePatternMatcher;
 
+        /// <summary>
+        /// Creates a new <see cref="TemplateMatcher"/> instance given a <paramref name="template"/> and <paramref name="defaults"/>.
+        /// </summary>
+        /// <param name="template">The <see cref="RouteTemplate"/> to compare against.</param>
+        /// <param name="defaults">The default values for parameters in the <paramref name="template"/>.</param>
         public TemplateMatcher(
             RouteTemplate template,
             RouteValueDictionary defaults)
@@ -62,10 +70,23 @@ namespace Microsoft.AspNetCore.Routing.Template
             _routePatternMatcher = new RoutePatternMatcher(routePattern, Defaults);
         }
 
+        /// <summary>
+        /// Gets the default values for parameters in the <see cref="Template"/>.
+        /// </summary>
         public RouteValueDictionary Defaults { get; }
 
+        /// <summary>
+        /// Gets the <see cref="RouteTemplate"/> to match against.
+        /// </summary>
         public RouteTemplate Template { get; }
 
+        /// <summary>
+        /// Evaluates if the provided <paramref name="path"/> matches the <see cref="Template"/>. Populates
+        /// <paramref name="values"/> with parameter values.
+        /// </summary>
+        /// <param name="path">A <see cref="PathString"/> representing the route to match.</param>
+        /// <param name="values">A <see cref="RouteValueDictionary"/> to populate with parameter values.</param>
+        /// <returns><see langword="true"/> if <paramref name="path"/> matches <see cref="Template"/>.</returns>
         public bool TryMatch(PathString path, RouteValueDictionary values)
         {
             if (values == null)

src/Http/Routing/src/Template/TemplateParser.cs

@@ -6,8 +6,16 @@ using Microsoft.AspNetCore.Routing.Patterns;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Provides methods for parsing route template strings.
+    /// </summary>
     public static class TemplateParser
     {
+        /// <summary>
+        /// Creates a <see cref="RouteTemplate"/> for a given <paramref name="routeTemplate"/> string.
+        /// </summary>
+        /// <param name="routeTemplate">A string representation of the route template.</param>
+        /// <returns>A <see cref="RouteTemplate"/> instance.</returns>
         public static RouteTemplate Parse(string routeTemplate)
         {
             if (routeTemplate == null)

src/Http/Routing/src/Template/TemplatePart.cs

@@ -10,13 +10,23 @@ using Microsoft.AspNetCore.Routing.Patterns;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Represents a part of a route template segment.
+    /// </summary>
     [DebuggerDisplay("{DebuggerToString()}")]
     public class TemplatePart
     {
+        /// <summary>
+        /// Constructs a new <see cref="TemplatePart"/> instance.
+        /// </summary>
         public TemplatePart()
         {
         }
 
+        /// <summary>
+        /// Constructs a new <see cref="TemplatePart"/> instance given a <paramref name="other"/>.
+        /// </summary>
+        /// <param name="other">A <see cref="RoutePatternPart"/> instance representing the route part.</param>
         public TemplatePart(RoutePatternPart other)
         {
             IsLiteral = other.IsLiteral || other.IsSeparator;
@@ -47,6 +57,11 @@ namespace Microsoft.AspNetCore.Routing.Template
             }
         }
 
+        /// <summary>
+        /// Create a <see cref="TemplatePart"/> representing a literal route part.
+        /// </summary>
+        /// <param name="text">The text of the literate route part.</param>
+        /// <returns>A <see cref="TemplatePart"/> instance.</returns>
         public static TemplatePart CreateLiteral(string text)
         {
             return new TemplatePart()
@@ -56,6 +71,15 @@ namespace Microsoft.AspNetCore.Routing.Template
             };
         }
 
+        /// <summary>
+        /// Creates a <see cref="TemplatePart"/> representing a paramter part.
+        /// </summary>
+        /// <param name="name">The name of the parameter.</param>
+        /// <param name="isCatchAll"><see langword="true"/> if the parameter is a catch-all parameter.</param>
+        /// <param name="isOptional"><see langword="true"/> if the parameter is an optional parameter.</param>
+        /// <param name="defaultValue">The default value of the parameter.</param>
+        /// <param name="inlineConstraints">A collection of constraints associated with the parameter.</param>
+        /// <returns>A <see cref="TemplatePart"/> instance.</returns>
         public static TemplatePart CreateParameter(
             string name,
             bool isCatchAll,
@@ -79,14 +103,41 @@ namespace Microsoft.AspNetCore.Routing.Template
             };
         }
 
+        /// <summary>
+        /// <see langword="true"/> if the route part is is a catch-all part (e.g. /*).
+        /// </summary>
         public bool IsCatchAll { get; private set; }
+        /// <summary>
+        /// <see langword="true"/> if the route part is represents a literal value.
+        /// </summary>
         public bool IsLiteral { get; private set; }
+        /// <summary>
+        /// <see langword="true"/> if the route part represents a parameterized value.
+        /// </summary>
         public bool IsParameter { get; private set; }
+        /// <summary>
+        /// <see langword="true"/> if the route part represents an optional part.
+        /// </summary>
         public bool IsOptional { get; private set; }
+        /// <summary>
+        /// <see langword="true"/> if the route part represents an optional seperator.
+        /// </summary>
         public bool IsOptionalSeperator { get; set; }
+        /// <summary>
+        /// The name of the route parameter. Can be null.
+        /// </summary>
         public string? Name { get; private set; }
+        /// <summary>
+        /// The textual representation of the route paramter. Can be null. Used to represent route seperators and literal parts.
+        /// </summary>
         public string? Text { get; private set; }
+        /// <summary>
+        /// The default value for route paramters. Can be null.
+        /// </summary>
         public object? DefaultValue { get; private set; }
+        /// <summary>
+        /// The constraints associates with a route paramter.
+        /// </summary>
         public IEnumerable<InlineConstraint> InlineConstraints { get; private set; } = Enumerable.Empty<InlineConstraint>();
 
         internal string? DebuggerToString()
@@ -101,6 +152,10 @@ namespace Microsoft.AspNetCore.Routing.Template
             }
         }
 
+        /// <summary>
+        /// Creates a <see cref="RoutePatternPart"/> for the route part designated by the <see cref="TemplatePart"/>.
+        /// </summary>
+        /// <returns>A <see cref="RoutePatternPart"/> instance.</returns>
         public RoutePatternPart ToRoutePatternPart()
         {
             if (IsLiteral && IsOptionalSeperator)

src/Http/Routing/src/Template/TemplateSegment.cs

@@ -9,14 +9,24 @@ using Microsoft.AspNetCore.Routing.Patterns;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
+    /// <summary>
+    /// Represents a segment of a route template.
+    /// </summary>
     [DebuggerDisplay("{DebuggerToString()}")]
     public class TemplateSegment
     {
+        /// <summary>
+        /// Constructs a new <see cref="TemplateSegment"/> instance.
+        /// </summary>
         public TemplateSegment()
         {
             Parts = new List<TemplatePart>();
         }
 
+        /// <summary>
+        /// Constructs a new <see cref="TemplateSegment"/> instance given another <see cref="RoutePatternPathSegment"/>.
+        /// </summary>
+        /// <param name="other">A <see cref="RoutePatternPathSegment"/> instance.</param>
         public TemplateSegment(RoutePatternPathSegment other)
         {
             if (other == null)
@@ -32,8 +42,14 @@ namespace Microsoft.AspNetCore.Routing.Template
             }
         }
 
+        /// <summary>
+        /// <see langword="true"/> if the segment contains a single entry.
+        /// </summary>
         public bool IsSimple => Parts.Count == 1;
 
+        /// <summary>
+        /// Gets the list of individual parts in the template segment.
+        /// </summary>
         public List<TemplatePart> Parts { get; }
 
         internal string DebuggerToString()
@@ -41,6 +57,10 @@ namespace Microsoft.AspNetCore.Routing.Template
             return string.Join(string.Empty, Parts.Select(p => p.DebuggerToString()));
         }
 
+        /// <summary>
+        /// Returns a <see cref="RoutePatternPathSegment"/> for the template segment.
+        /// </summary>
+        /// <returns>A <see cref="RoutePatternPathSegment"/> instance.</returns>
         public RoutePatternPathSegment ToRoutePatternPathSegment()
         {
             var parts = Parts.Select(p => p.ToRoutePatternPart());

src/Http/Routing/src/Tree/TreeRouter.cs

@@ -19,8 +19,10 @@ namespace Microsoft.AspNetCore.Routing.Tree
     /// </summary>
     public class TreeRouter : IRouter
     {
-        // Key used by routing and action selection to match an attribute route entry to a
+        /// <summary>
-        // group of action descriptors.
+        /// Key used by routing and action selection to match an attribute
+        /// route entry to agroup of action descriptors.
+        /// </summary>
         public static readonly string RouteGroupKey = "!__route_group";
 
         private readonly LinkGenerationDecisionTree _linkGenerationTree;