Added more direct routing APIs (#2147)

* Added more direct routing APIs
- Added helpers to make direct routing more easily accessible.
- Updated the sample to use them.

* Dedupe more

samples/ReverseProxy.Direct.Sample/Startup.cs

@@ -82,6 +82,8 @@ public void Configure(IApplicationBuilder app, IHttpForwarder forwarder)
                     }
                 });
 
+                endpoints.MapForwarder("/sample/{id}", "https://httpbin.org", "/anything/{id}");
+                endpoints.MapForwarder("/sample/anything/{id}", "https://httpbin.org", b => b.AddPathRemovePrefix("/sample"));
 
                 // When using extension methods for registering IHttpForwarder providing configuration, transforms, and HttpMessageInvoker is optional (defaults will be used).
                 endpoints.MapForwarder("/{**catch-all}", "https://example.com", requestOptions, transformer, httpClient);

src/ReverseProxy/Routing/DirectForwardingIEndpointRouteBuilderExtensions.cs

@@ -6,6 +6,8 @@
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection;
 using Yarp.ReverseProxy.Forwarder;
+using Yarp.ReverseProxy.Transforms;
+using Yarp.ReverseProxy.Transforms.Builder;
 
 namespace Microsoft.AspNetCore.Builder;
 
@@ -22,6 +24,42 @@ public static IEndpointConventionBuilder MapForwarder(this IEndpointRouteBuilder
         return endpoints.MapForwarder(pattern, destinationPrefix, ForwarderRequestConfig.Empty);
     }
 
+    /// <summary>
+    /// Adds direct forwarding of HTTP requests that match the specified pattern to a specific destination and target path applying route values from the pattern using default configuration for the outgoing request, and default HTTP client.
+    /// </summary>
+    public static IEndpointConventionBuilder MapForwarder(this IEndpointRouteBuilder endpoints, string pattern, string destinationPrefix, string targetPath)
+    {
+        return endpoints.MapForwarder(pattern, destinationPrefix, ForwarderRequestConfig.Empty, targetPath);
+    }
+
+    /// <summary>
+    /// Adds direct forwarding of HTTP requests that match the specified pattern to a specific destination and target path applying route values from the pattern using customized configuration for the outgoing request, and default HTTP client.
+    /// </summary>
+    public static IEndpointConventionBuilder MapForwarder(this IEndpointRouteBuilder endpoints, string pattern, string destinationPrefix, ForwarderRequestConfig requestConfig, string targetPath)
+    {
+        return endpoints.MapForwarder(pattern, destinationPrefix, requestConfig, b => b.AddPathRouteValues(targetPath));
+    }
+
+    /// <summary>
+    /// Adds direct forwarding of HTTP requests that match the specified pattern to a specific destination using default configuration for the outgoing request, customized transforms, and default HTTP client.
+    /// </summary>
+    public static IEndpointConventionBuilder MapForwarder(this IEndpointRouteBuilder endpoints, string pattern, string destinationPrefix, Action<TransformBuilderContext> configureTransform)
+    {
+        return endpoints.MapForwarder(pattern, destinationPrefix, ForwarderRequestConfig.Empty, configureTransform);
+    }
+
+    /// <summary>
+    /// Adds direct forwarding of HTTP requests that match the specified pattern to a specific destination using customized configuration for the outgoing request, customized transforms, and default HTTP client.
+    /// </summary>
+    public static IEndpointConventionBuilder MapForwarder(this IEndpointRouteBuilder endpoints, string pattern, string destinationPrefix, ForwarderRequestConfig requestConfig, Action<TransformBuilderContext> configureTransform)
+    {
+        var transformBuilder = endpoints.ServiceProvider.GetRequiredService<ITransformBuilder>();
+
+        var transformer = transformBuilder.Create(configureTransform);
+
+        return endpoints.MapForwarder(pattern, destinationPrefix, requestConfig, transformer);
+    }
+
     /// <summary>
     /// Adds direct forwarding of HTTP requests that match the specified pattern to a specific destination using customized configuration for the outgoing request, default transforms, and default HTTP client.
     /// </summary>