Fix behaviour for Preflight requests on the ODataBatchMiddleware. (#2356)

Author: marabooy

src/Microsoft.AspNetCore.OData/Batch/ODataBatchMiddleware.cs

@@ -34,13 +34,15 @@ public ODataBatchMiddleware(RequestDelegate next)
         /// <returns>A task that can be awaited.</returns>
         public async Task Invoke(HttpContext context)
         {
-            // Attempt to match the path to a bach route.
+            HttpRequest request = context.Request;
+            bool isPreFlight = HttpMethods.IsOptions(request.Method);
+           
+            // Attempt to match the path to a batch route.
             ODataBatchPathMapping batchMapping = context.RequestServices.GetRequiredService<ODataBatchPathMapping>();
 
-            string routeName;
-            if (batchMapping.TryGetRouteName(context, out routeName))
+            if (!isPreFlight && batchMapping.TryGetRouteName(context, out string routeName))
             {
-                // Get the per-route continer and retrieve the batch handler.
+                // Get the per-route container and retrieve the batch handler.
                 IPerRouteContainer perRouteContainer = context.RequestServices.GetRequiredService<IPerRouteContainer>();
                 if (perRouteContainer == null)
                 {

test/UnitTest/Microsoft.AspNet.OData.Test.Shared/Batch/ODataBatchMiddlewareTests.cs

@@ -0,0 +1,84 @@
+#if NETCORE
+using System.Net.Http;
+using System.Threading.Tasks;
+using Microsoft.AspNet.OData.Batch;
+using Microsoft.AspNet.OData.Extensions;
+using Microsoft.AspNet.OData.Test.Abstraction;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.OData;
+using Xunit;
+using ServiceLifetime = Microsoft.OData.ServiceLifetime;
+
+namespace Microsoft.AspNet.OData.Test.Batch
+{
+    public class ODataBatchMiddlewareTests
+    {
+        private const string URI = "http://localhost/$batch";
+
+        private readonly ODataBatchMiddleware _batchMiddleware;
+        private readonly IRouteBuilder _routeBuilder;
+
+        public ODataBatchMiddlewareTests()
+        {
+            _batchMiddleware = new ODataBatchMiddleware(CorsDelegate);
+            _routeBuilder = RoutingConfigurationFactory.CreateWithRootContainer("odata");
+            _routeBuilder.MapODataServiceRoute("odata", "odata", b =>
+            {
+                b.AddService<ODataBatchHandler>(ServiceLifetime.Singleton,
+                    implementationFactory => new TestODataBatchHandler());
+            });
+        }
+
+        private HttpRequest CreateRequest(HttpMethod method)
+        {
+            
+            HttpRequest request = RequestFactory.Create(method, URI, this._routeBuilder, "odata");
+            ODataBatchPathMapping batchMapping =
+                request.HttpContext.RequestServices.GetRequiredService<ODataBatchPathMapping>();
+            batchMapping.AddRoute("odata", "/$batch");
+            return request;
+        }
+
+        [Fact]
+        public async Task BatchMiddlewareShouldNotHandlePreflightRequests()
+        {
+            var request = CreateRequest(HttpMethod.Options);
+
+            await _batchMiddleware.Invoke(request.HttpContext);
+
+            Assert.True(request.HttpContext.Items.ContainsKey("TestKey"));
+        }
+
+        [Fact]
+        public async Task BatchMiddlewareShouldWorkNormallyForNonPreflightRequests()
+        {
+            var request = CreateRequest(HttpMethod.Post);
+            await _batchMiddleware.Invoke(request.HttpContext);
+
+            Assert.False(request.HttpContext.Items.ContainsKey("TestKey"));
+        }
+
+
+
+        private Task CorsDelegate(HttpContext context)
+        {
+            // This mocks the execution of the cors middleware which should be registered for cors to work normally.
+            // the ODatabatch middleware should not process the request but instead pass it on to the next middleware for cors to work as expected.
+            // https://github.com/dotnet/aspnetcore/blob/master/src/Middleware/CORS/src/Infrastructure/CorsMiddleware.cs
+            context.Items.Add("TestKey", "TestValue");
+            return Task.CompletedTask;
+        }
+
+    }
+
+    public class TestODataBatchHandler : DefaultODataBatchHandler
+    {
+        public override Task ProcessBatchAsync(HttpContext context, RequestDelegate nextHandler)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}
+#endif

test/UnitTest/Microsoft.AspNet.OData.Test.Shared/Microsoft.AspNet.OData.Test.Shared.projitems

@@ -17,6 +17,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Batch\MockHttpServer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchContentTest.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchHttpRequestMessageExtensionsTest.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchMiddlewareTests.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchReaderExtensionsTest.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchRequestHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Batch\ODataBatchRequestItemTest.cs" />