Merge pull request #15 from ejball/disable-sse-buffering

Directory.Build.props

@@ -1,8 +1,8 @@
 <Project>
 
   <PropertyGroup>
-    <VersionPrefix>3.10.0</VersionPrefix>
-    <PackageValidationBaselineVersion>3.9.0</PackageValidationBaselineVersion>
+    <VersionPrefix>3.10.1</VersionPrefix>
+    <PackageValidationBaselineVersion>3.10.0</PackageValidationBaselineVersion>
     <LangVersion>12.0</LangVersion>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>

ReleaseNotes.md

@@ -1,5 +1,9 @@
 # Release Notes
 
+## 3.10.1
+
+* Disable buffering for text/event-stream.
+
 ## 3.10.0
 
 * Support events.

conformance/WebApiControllerServer/WebApiControllerServerApp.cs

@@ -37,14 +37,15 @@ public void Configuration(IAppBuilder app)
 		{
 			var configuration = new HttpConfiguration();
 			configuration.MapHttpAttributeRoutes();
-			configuration.Services.Replace(typeof(IHostBufferPolicySelector), new NoBufferPolicySelector());
+			configuration.Services.Replace(typeof(IHostBufferPolicySelector), new SseBufferPolicySelector(configuration.Services.GetHostBufferPolicySelector()));
 			app.UseWebApi(configuration);
 		}
 
-		private sealed class NoBufferPolicySelector : IHostBufferPolicySelector
+		private sealed class SseBufferPolicySelector(IHostBufferPolicySelector? inner) : IHostBufferPolicySelector
 		{
-			public bool UseBufferedInputStream(object hostContext) => false;
-			public bool UseBufferedOutputStream(HttpResponseMessage response) => false; //// required for event streaming
+			public bool UseBufferedInputStream(object hostContext) => inner?.UseBufferedInputStream(hostContext) ?? false;
+			public bool UseBufferedOutputStream(HttpResponseMessage response) =>
+				response.Content.Headers.ContentType?.MediaType != "text/event-stream" && (inner?.UseBufferedOutputStream(response) ?? false);
 		}
 	}
 

conformance/WebApiMiddlewareServer/WebApiMiddlewareServerApp.cs

@@ -34,14 +34,15 @@ public void Configuration(IAppBuilder app)
 				Tests = LoadTests(),
 				JsonSerializer = JsonSerializer,
 			})));
-			configuration.Services.Replace(typeof(IHostBufferPolicySelector), new NoBufferPolicySelector());
+			configuration.Services.Replace(typeof(IHostBufferPolicySelector), new SseBufferPolicySelector(configuration.Services.GetHostBufferPolicySelector()));
 			app.UseWebApi(configuration);
 		}
 
-		private sealed class NoBufferPolicySelector : IHostBufferPolicySelector
+		private sealed class SseBufferPolicySelector(IHostBufferPolicySelector? inner) : IHostBufferPolicySelector
 		{
-			public bool UseBufferedInputStream(object hostContext) => false;
-			public bool UseBufferedOutputStream(HttpResponseMessage response) => false; //// required for event streaming
+			public bool UseBufferedInputStream(object hostContext) => inner?.UseBufferedInputStream(hostContext) ?? false;
+			public bool UseBufferedOutputStream(HttpResponseMessage response) =>
+				response.Content.Headers.ContentType?.MediaType != "text/event-stream" && (inner?.UseBufferedOutputStream(response) ?? false);
 		}
 	}
 

src/Facility.AspNetCore/FacilityAspNetCoreUtility.cs

@@ -3,6 +3,7 @@
 using Facility.Core.Http;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Extensions;
+using Microsoft.AspNetCore.Http.Features;
 
 namespace Facility.AspNetCore;
 
@@ -62,20 +63,22 @@ public static HttpResponseMessage CreateHttpResponseMessage(ServiceErrorDto erro
 	/// </summary>
 	public static async Task WriteHttpResponseMessageAsync(HttpResponseMessage httpResponseMessage, HttpResponse contextResponse)
 	{
-		contextResponse.StatusCode = (int) httpResponseMessage.StatusCode;
+		// disable buffering for text/event-stream
+		var contentHeaders = httpResponseMessage.Content.Headers;
+		if (contentHeaders.ContentType?.MediaType == "text/event-stream")
+			contextResponse.HttpContext.Features.Get<IHttpResponseBodyFeature>()?.DisableBuffering();
 
-		var responseHeaders = httpResponseMessage.Headers;
+		contextResponse.StatusCode = (int) httpResponseMessage.StatusCode;
 
 		// Ignore the Transfer-Encoding header if it is just "chunked".
 		// We let the host decide about whether the response should be chunked or not.
+		var responseHeaders = httpResponseMessage.Headers;
 		if (responseHeaders is { TransferEncodingChunked: true, TransferEncoding.Count: 1 })
 			responseHeaders.TransferEncoding.Clear();
 
 		foreach (var header in responseHeaders)
 			contextResponse.Headers.Append(header.Key, header.Value.ToArray());
 
-		var contentHeaders = httpResponseMessage.Content.Headers;
-
 		// Copy the response content headers only after ensuring they are complete.
 		// We ask for Content-Length first because HttpContent lazily computes this
 		// and only afterward writes the value into the content headers.