Fix for #147

src/System.Web.Http.Cors/CorsMessageHandler.cs

@@ -73,7 +73,9 @@ protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage
                 catch (Exception exception)
                 {
                     if (_rethrowExceptions)
+                    {
                         throw;
+                    }
 
                     return HandleException(request, exception);
                 }

test/System.Web.Http.Cors.Test/Controllers/ThrowingController.cs

@@ -0,0 +1,11 @@
+namespace System.Web.Http.Cors
+{
+    [EnableCors("*", "*", "*")]
+    public class ThrowingController : ApiController
+    {
+        public string Get()
+        {
+            throw new Exception();
+        }
+    }
+}

test/System.Web.Http.Cors.Test/CorsMessageHandlerTest.cs

@@ -7,13 +7,22 @@
 using System.Threading;
 using System.Threading.Tasks;
 using System.Web.Cors;
+using System.Web.Http.ExceptionHandling;
 using System.Web.Http.Hosting;
 using Microsoft.TestCommon;
 
 namespace System.Web.Http.Cors
 {
     public class CorsMessageHandlerTest
     {
+        private class PassthroughExceptionHandler : IExceptionHandler
+        {
+            public Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken)
+            {
+                throw context.Exception;
+            }
+        }
+
         [Fact]
         public void Constructor_NullConfig_Throws()
         {
@@ -180,6 +189,40 @@ public async Task SendAsync_HandlesExceptions_ThrownDuringPreflight()
             Assert.Equal(HttpStatusCode.MethodNotAllowed, response.StatusCode);
         }
 
+        [Fact]
+        public async Task SendAsync_Preflight_RethrowsExceptions_WhenRethrowFlagIsTrue()
+        {
+            HttpConfiguration config = new HttpConfiguration();
+            config.Routes.MapHttpRoute("default", "{controller}");
+            HttpServer server = new HttpServer(config);
+            CorsMessageHandler corsHandler = new CorsMessageHandler(config, true);
+            corsHandler.InnerHandler = server;
+            HttpMessageInvoker invoker = new HttpMessageInvoker(corsHandler);
+            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Options, "http://localhost/sample");
+            request.SetConfiguration(config);
+            request.Headers.Add(CorsConstants.Origin, "http://localhost");
+            request.Headers.Add(CorsConstants.AccessControlRequestMethod, "RandomMethod");
+
+            await Assert.ThrowsAsync<HttpResponseException>(() => invoker.SendAsync(request, CancellationToken.None));
+        }
+
+        [Fact]
+        public async Task SendAsync_RethrowsExceptions_WhenRethrowFlagIsTrue()
+        {
+            HttpConfiguration config = new HttpConfiguration();
+            config.Routes.MapHttpRoute("default", "{controller}");
+            config.Services.Replace(typeof(IExceptionHandler), new PassthroughExceptionHandler());
+            HttpServer server = new HttpServer(config);
+            CorsMessageHandler corsHandler = new CorsMessageHandler(config, true);
+            corsHandler.InnerHandler = server;
+            HttpMessageInvoker invoker = new HttpMessageInvoker(corsHandler);
+            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "http://localhost/throwing");
+            request.SetConfiguration(config);
+            request.Headers.Add(CorsConstants.Origin, "http://localhost");
+
+            await Assert.ThrowsAsync<Exception>(() => invoker.SendAsync(request, CancellationToken.None));
+        }
+
         [Fact]
         public Task HandleCorsRequestAsync_NullConfig_Throws()
         {

test/System.Web.Http.Cors.Test/System.Web.Http.Cors.Test.csproj

@@ -82,6 +82,7 @@
     <Compile Include="Controllers\PerControllerConfigController.cs" />
     <Compile Include="Controllers\SampleController.cs" />
     <Compile Include="Controllers\DefaultController.cs" />
+    <Compile Include="Controllers\ThrowingController.cs" />
     <Compile Include="CorsMessageHandlerTest.cs" />
     <Compile Include="DisableCorsAttributeTest.cs" />
     <Compile Include="EnableCorsAttributeTest.cs" />