Server Reset/Trailers docs (#20059)

* HTTP.SYS and IIS docs

* fixups

* Updates

* Updates

* Update

* feedback

* Feedback

* Feedback

* fb

* fix path

* protocols

* oops

* Update aspnetcore/includes/trailers.md

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

* Update protocols.md (#20079)

* Update protocols.md

* Update protocols.md

* Apply suggestions from code review

Co-authored-by: Luke Latham <llatham@aquent.com>

* Apply suggestions from code review

Co-authored-by: Luke Latham <llatham@aquent.com>

* Update aspnetcore/host-and-deploy/iis/protocols.md

Co-authored-by: Luke Latham <llatham@aquent.com>

Co-authored-by: Luke Latham <llatham@aquent.com>

Co-authored-by: Luke Latham <llatham@aquent.com>
Co-authored-by: James Newton-King <james@newtonking.com>
Co-authored-by: Rick Anderson <3605364+Rick-Anderson@users.noreply.github.com>

Author: 4 people

aspnetcore/fundamentals/servers/httpsys.md

@@ -256,6 +256,23 @@ In Visual Studio, the default launch profile is for IIS Express. To run the proj
 
 For apps hosted by HTTP.sys that interact with requests from the Internet or a corporate network, additional configuration might be required when hosting behind proxy servers and load balancers. For more information, see [Configure ASP.NET Core to work with proxy servers and load balancers](xref:host-and-deploy/proxy-load-balancer).
 
+## Advanced HTTP/2 features to support gRPC
+
+Additional HTTP/2 features in HTTP.sys support gRPC, including support for response trailers and sending reset frames.
+
+Requirements to run gRPC with HTTP.SYS:
+
+* Windows 10, OS Build 19041.508 or later
+* TLS 1.2 or later connection
+
+### Trailers
+
+[!INCLUDE[](~/includes/trailers.md)]
+
+### Reset
+
+[!INCLUDE[](~/includes/reset.md)]
+
 ## Additional resources
 
 * [Enable Windows Authentication with HTTP.sys](xref:security/authentication/windowsauth#httpsys)
@@ -1021,4 +1038,4 @@ For apps hosted by HTTP.sys that interact with requests from the Internet or a c
 * [The host](xref:fundamentals/index#host)
 * <xref:test/troubleshoot>
 
-::: moniker-end
+::: moniker-end

aspnetcore/fundamentals/servers/kestrel.md

@@ -340,6 +340,14 @@ webBuilder.ConfigureKestrel(serverOptions =>
 
 The default value is 96 KB (98,304).
 
+### Trailers
+
+[!INCLUDE[](~/includes/trailers.md)]
+
+### Reset
+
+[!INCLUDE[](~/includes/reset.md)]
+
 ### Synchronous I/O
 
 <xref:Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerOptions.AllowSynchronousIO> controls whether synchronous I/O is allowed for the request and response. The default value is `false`.

aspnetcore/host-and-deploy/iis/index.md

@@ -533,24 +533,6 @@ ICACLS C:\sites\MyWebApp /grant "IIS AppPool\DefaultAppPool":F
 
 For more information, see the [icacls](/windows-server/administration/windows-commands/icacls) topic.
 
-## HTTP/2 support
-
-[HTTP/2](https://httpwg.org/specs/rfc7540.html) is supported with ASP.NET Core in the following IIS deployment scenarios:
-
-* In-process
-  * Windows Server 2016/Windows 10 or later; IIS 10 or later
-  * TLS 1.2 or later connection
-* Out-of-process
-  * Windows Server 2016/Windows 10 or later; IIS 10 or later
-  * Public-facing edge server connections use HTTP/2, but the reverse proxy connection to the [Kestrel server](xref:fundamentals/servers/kestrel) uses HTTP/1.1.
-  * TLS 1.2 or later connection
-
-For an in-process deployment when an HTTP/2 connection is established, [HttpRequest.Protocol](xref:Microsoft.AspNetCore.Http.HttpRequest.Protocol*) reports `HTTP/2`. For an out-of-process deployment when an HTTP/2 connection is established, [HttpRequest.Protocol](xref:Microsoft.AspNetCore.Http.HttpRequest.Protocol*) reports `HTTP/1.1`.
-
-For more information on the in-process and out-of-process hosting models, see <xref:host-and-deploy/aspnet-core-module>.
-
-HTTP/2 is enabled by default. Connections fall back to HTTP/1.1 if an HTTP/2 connection isn't established. For more information on HTTP/2 configuration with IIS deployments, see [HTTP/2 on IIS](/iis/get-started/whats-new-in-iis-10/http2-on-iis).
-
 ## CORS preflight requests
 
 *This section only applies to ASP.NET Core apps that target the .NET Framework.*

aspnetcore/host-and-deploy/iis/protocols.md

@@ -0,0 +1,46 @@
+---
+title: Use ASP.NET Core with HTTP/2 on IIS
+author: rick-anderson
+description: Learn how to use HTTP/2 features with IIS.
+monikerRange: '>= aspnetcore-5.0'
+ms.author: riande
+ms.custom: mvc
+ms.date: 01/13/2020
+no-loc: ["ASP.NET Core Identity", cookie, Cookie, Blazor, "Blazor Server", "Blazor WebAssembly", "Identity", "Let's Encrypt", Razor, SignalR]
+uid: host-and-deploy/iis/protocols
+---
+
+# Use ASP.NET Core with HTTP/2 on IIS
+
+By [Justin Kotalik](https://github.com/jkotalik)
+
+[HTTP/2](https://httpwg.org/specs/rfc7540.html) is supported with ASP.NET Core in the following IIS deployment scenarios:
+
+* Windows Server 2016 or later / Windows 10 or later
+* IIS 10 or later
+* TLS 1.2 or later connection
+* When [hosting out-of-process](xref:host-and-deploy/iis/index#out-of-process-hosting-model): Public-facing edge server connections use HTTP/2, but the reverse proxy connection to the [Kestrel server](xref:fundamentals/servers/kestrel) uses HTTP/1.1.
+
+For an in-process deployment when an HTTP/2 connection is established, [`HttpRequest.Protocol`](xref:Microsoft.AspNetCore.Http.HttpRequest.Protocol*) reports `HTTP/2`. For an out-of-process deployment when an HTTP/2 connection is established, [`HttpRequest.Protocol`](xref:Microsoft.AspNetCore.Http.HttpRequest.Protocol*) reports `HTTP/1.1`.
+
+For more information on the in-process and out-of-process hosting models, see <xref:host-and-deploy/aspnet-core-module>.
+
+HTTP/2 is enabled by default for HTTPS/TLS connections. Connections fall back to HTTP/1.1 if an HTTP/2 connection isn't established. For more information on HTTP/2 configuration with IIS deployments, see [HTTP/2 on IIS](/iis/get-started/whats-new-in-iis-10/http2-on-iis).
+
+## Advanced HTTP/2 features to support gRPC
+
+Additional HTTP/2 features in IIS support gRPC, including support for response trailers and sending reset frames.
+
+Requirements to run gRPC on IIS:
+
+* In-process hosting.
+* Windows 10, OS Build 20300.1000 or later. May require use of Windows Insider Builds.
+* TLS 1.2 or later connection
+
+### Trailers
+
+[!INCLUDE[](~/includes/trailers.md)]
+
+### Reset
+
+[!INCLUDE[](~/includes/reset.md)]

aspnetcore/includes/reset.md

@@ -0,0 +1,8 @@
+Reset allows for the server to reset a HTTP/2 request with a specified error code. A reset request is considered aborted.
+
+```csharp
+var resetFeature = httpContext.Features.Get<IHttpResetFeature>();
+resetFeature.Reset(errorCode: 2);
+```
+
+`Reset` in the preceding code example specifies the `INTERNAL_ERROR` error code. For more information about HTTP/2 error codes, visit the [HTTP/2 specification error code section](https://tools.ietf.org/html/rfc7540#page-50).

aspnetcore/includes/trailers.md

@@ -0,0 +1,19 @@
+HTTP Trailers are similar to HTTP Headers, except they are sent after the response body is sent. For IIS and HTTP.SYS, only HTTP/2 response trailers are supported.
+
+```csharp
+if (httpContext.Response.SupportsTrailers())
+{
+    httpContext.Response.DeclareTrailer("trailername");	
+
+    // Write body
+    httpContext.Response.WriteAsync("Hello world");
+
+    httpContext.Response.AppendTrailer("trailername", "TrailerValue");
+}
+```
+
+In the preceding example code:
+
+* `SupportsTrailers` ensures that trailers are supported for the response.
+* `DeclareTrailer` adds the given trailer name to the `Trailer` response header. Declaring a response's trailers is optional, but recommended. If `DeclareTrailer` is called, it must be before the response headers are sent.
+* `AppendTrailer` appends the trailer.

aspnetcore/toc.yml

@@ -933,6 +933,9 @@
         - name: Transform web.config
           displayName: deploy, publish
           uid: host-and-deploy/iis/transform-webconfig
+        - name: HTTP/2
+          displayName: deploy, publish
+          uid: host-and-deploy/iis/protocols
     - name: Kestrel
       uid: fundamentals/servers/kestrel
       displayName: deploy, publish, server