Bug fix/race condition in get soap action

src/SoapCore.Tests/HeadersHelperThreadingTest.cs

@@ -0,0 +1,52 @@
+using System;
+using System.ServiceModel.Channels;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace SoapCore.Tests
+{
+	[TestClass]
+	public class HeadersHelperThreadingTest
+	{
+		[TestMethod]
+		public void GetSoapAction_IsThreadSafe()
+		{
+			// Arrange
+			const int totalOperations = 200_000;
+			var exceptions = new System.Collections.Concurrent.ConcurrentQueue<Exception>();
+
+			// Act
+			Parallel.For(0, totalOperations, (i, loopState) =>
+			{
+				try
+				{
+					var httpContext = new DefaultHttpContext();
+
+					// Add variability to the action to ensure the parsing logic is stressed
+					var action = $"http://test-uri.org/IService/TestAction{i % 100}";
+					httpContext.Request.Headers["Content-Type"] = $"application/soap+xml; charset=utf-8; action=\"{action}\"";
+					var message = Message.CreateMessage(MessageVersion.Soap12WSAddressing10, "action");
+
+					// The ref message is modified by GetSoapAction, so we need to pass it in a way that can be updated.
+					var messageRef = new Message[1] { message };
+					var soapAction = HeadersHelper.GetSoapAction(httpContext, ref messageRef[0]);
+
+					// Assert
+					Assert.AreEqual(action, soapAction);
+				}
+				catch (Exception ex)
+				{
+					exceptions.Enqueue(ex);
+					loopState.Stop(); // Stop on first error to fail fast
+				}
+			});
+
+			// Assert
+			if (!exceptions.IsEmpty)
+			{
+				throw new AggregateException("One or more exceptions were thrown in worker threads.", exceptions);
+			}
+		}
+	}
+}

src/SoapCore/HeadersHelper.cs

@@ -9,7 +9,7 @@
 
 namespace SoapCore
 {
-	internal static class HeadersHelper
+	public static class HeadersHelper
 	{
 		private static readonly char[] ContentTypeSeparators = new[] { ';' };
 
@@ -47,49 +47,61 @@ public static string GetSoapAction(HttpContext httpContext, ref Message message)
 					}
 
 					var buff = ArrayPool<Range>.Shared.Rent(nInstances);
-					var rangeSpan = new Span<Range>(buff);
-					var nItems = itemSpan.Split(rangeSpan, ContentTypeSeparators, StringSplitOptions.RemoveEmptyEntries);
-
-					for (int i = 0; i < nItems; i++)
+					try
 					{
-						var headerItem = itemSpan[rangeSpan[i]].TrimStart();
-						if (headerItem.Length < 6)
-						{
-							continue;
-						}
+						var rangeSpan = new Span<Range>(buff);
+						var nItems = itemSpan.Split(rangeSpan, ContentTypeSeparators, StringSplitOptions.RemoveEmptyEntries);
+						bool found = false;
 
-						if (!headerItem.StartsWith("action".AsSpan(), StringComparison.OrdinalIgnoreCase))
+						for (int i = 0; i < nItems; i++)
 						{
-							continue;
-						}
+							var headerItem = itemSpan[rangeSpan[i]].TrimStart();
+							if (headerItem.Length < 6)
+							{
+								continue;
+							}
 
-						headerItem = headerItem.Slice(6).TrimStart();
+							if (!headerItem.StartsWith("action".AsSpan(), StringComparison.OrdinalIgnoreCase))
+							{
+								continue;
+							}
 
-						if (headerItem[0] != '=')
-						{
-							continue;
-						}
+							headerItem = headerItem.Slice(6).TrimStart();
 
-						headerItem = headerItem.Slice(1).TrimStart();
+							if (headerItem.Length == 0 || headerItem[0] != '=')
+							{
+								continue;
+							}
 
-						if (headerItem[0] != '"')
-						{
-							continue;
-						}
+							headerItem = headerItem.Slice(1).TrimStart();
 
-						headerItem = headerItem.Slice(1).TrimStart();
+							if (headerItem.Length == 0 || headerItem[0] != '"')
+							{
+								continue;
+							}
 
-						var quoteIndex = headerItem.IndexOf('"');
-						if (quoteIndex < 0)
-						{
-							continue;
+							headerItem = headerItem.Slice(1).TrimStart();
+
+							var quoteIndex = headerItem.IndexOf('"');
+							if (quoteIndex < 0)
+							{
+								continue;
+							}
+
+							soapAction = headerItem.Slice(0, quoteIndex);
+							found = true;
+							break;
 						}
 
+						if (found)
+						{
+							break;
+						}
+					}
+					finally
+					{
 						ArrayPool<Range>.Shared.Return(buff);
-						soapAction = headerItem.Slice(0, quoteIndex);
 					}
-
-					ArrayPool<Range>.Shared.Return(buff);
 				}
 
 #else

src/SoapCore/SoapEndpointMiddleware.cs

@@ -537,10 +537,9 @@ private async Task<Message> ProcessMessage(Message requestMessage, SoapMessageEn
 				reader?.Dispose();
 			}
 
-			// Execute response message filters
-			foreach (var messageFilter in asyncMessageFilters.Reverse())
+			for (var i = asyncMessageFilters.Length - 1; i >= 0; i--)
 			{
-				await messageFilter.OnResponseExecuting(responseMessage);
+				await asyncMessageFilters[i].OnResponseExecuting(responseMessage);
 			}
 
 			SetHttpResponse(httpContext, responseMessage);