Merge pull request #30 from Kentico/MVCHF11-3-initialization-exception

MVCHF11-3 - Fix issue with concurrent GlobalFilters registration

CHANGELOG.md

@@ -81,6 +81,11 @@
 
 ## Kentico.Content.Web.Mvc
 
+### 2.0.1 (2018-03-16)
+#### Fixed
+* Fix concurrent GlobalFilters registration which led to failed application initialization under high traffic.
+[#30](https://github.com/Kentico/Mvc/pull/30)
+
 ### 2.0.0 (2017-12-11)
 #### Release notes
 * This package version supports integration with Kentico 11.

src/Kentico.Content.Web.Mvc/ApplicationBuilderExtensions.cs

@@ -13,6 +13,8 @@ public static class ApplicationBuilderExtensions
         /// <param name="builder">The application builder.</param>
         public static void UsePreview(this ApplicationBuilder builder)
         {
+            PreviewGlobalFilters.Register();
+
             var module = new PreviewFeatureModule();
             builder.RegisterModule(module);
         }

src/Kentico.Content.Web.Mvc/Kentico.Content.Web.Mvc.csproj

@@ -51,6 +51,7 @@
     <Compile Include="HelperMethods\UrlHelperFileMethods.cs" />
     <Compile Include="IFeatureSetExtensions.cs" />
     <Compile Include="Preview\IPreviewFeature.cs" />
+    <Compile Include="Preview\PreviewGlobalFilters.cs" />
     <Compile Include="Preview\PreviewOutputCacheFilter.cs" />
     <Compile Include="Preview\PreviewFeature.cs" />
     <Compile Include="Preview\PreviewFeatureModule.cs" />

src/Kentico.Content.Web.Mvc/Preview/PreviewFeatureModule.cs

@@ -1,10 +1,10 @@
 using System;
 using System.Web;
-using System.Web.Mvc;
 using System.Web.Helpers;
 
 using CMS.DocumentEngine;
 using CMS.Helpers;
+
 using Kentico.Web.Mvc;
 
 namespace Kentico.Content.Web.Mvc
@@ -22,7 +22,6 @@ internal sealed class PreviewFeatureModule : IModule
         public void Initialize(HttpApplication application)
         {
             application.BeginRequest += HandleBeginRequest;
-            GlobalFilters.Filters.Add(new PreviewOutputCacheFilter());
         }
 
 

src/Kentico.Content.Web.Mvc/Preview/PreviewGlobalFilters.cs

@@ -0,0 +1,25 @@
+using System.Linq;
+using System.Web.Mvc;
+
+namespace Kentico.Content.Web.Mvc
+{
+    /// <summary>
+    /// Class that provides registration of all the required global filters for the page preview feature.
+    /// </summary>
+    internal static class PreviewGlobalFilters
+    {
+        /// <summary>
+        /// Registers global filters for the Preview feature.
+        /// </summary>
+        public static void Register()
+        {
+            var globalFilters = GlobalFilters.Filters;
+
+            // Add a filter to disable output cache for preview
+            if (!globalFilters.Any(f => f.Instance.GetType().Equals(typeof(PreviewOutputCacheFilter))))
+            {
+                globalFilters.Add(new PreviewOutputCacheFilter());
+            }
+        }
+    }
+}

src/Kentico.Content.Web.Mvc/Properties/AssemblyInfo.cs

@@ -14,6 +14,6 @@
 [assembly: Guid("430a1add-4583-459f-879c-a22a61e44a3b")]
 [assembly: AssemblyVersion("2.0.0.0")]
 [assembly: AssemblyFileVersion("2.0.0.0")]
-[assembly: AssemblyInformationalVersion("2.0.0")]
+[assembly: AssemblyInformationalVersion("2.0.1")]
 
 [assembly: InternalsVisibleTo("Kentico.Content.Web.Mvc.Tests")]

test/Kentico.Content.Web.Mvc.Tests/Kentico.Content.Web.Mvc.Tests.csproj

@@ -47,6 +47,7 @@
     <Compile Include="HelperMethods\NameValueCollectionExtensionsTests.cs" />
     <Compile Include="HelperMethods\SizeConstraintTests.cs" />
     <Compile Include="HelperMethods\UrlHelperFileMethodsTests.cs" />
+    <Compile Include="Preview\PreviewGlobalFiltersTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>

test/Kentico.Content.Web.Mvc.Tests/Preview/PreviewGlobalFiltersTests.cs

@@ -0,0 +1,59 @@
+using System.Linq;
+using System.Web.Mvc;
+
+using CMS.Tests;
+
+using NUnit.Framework;
+
+namespace Kentico.Content.Web.Mvc.Tests
+{
+    /// <summary>
+    /// Unit tests for class <see cref="PreviewGlobalFiltersTests"/>.
+    /// </summary>
+    public class PreviewGlobalFiltersTests
+    {
+        [TestFixture]
+        [Category.Unit]
+        public class RegisterTests
+        {
+            [SetUp]
+            public void SetUp()
+            {
+                GlobalFilters.Filters.Clear();
+            }
+
+
+            [OneTimeTearDown]
+            public void OneTimeTearDown()
+            {
+                GlobalFilters.Filters.Clear();
+            }
+
+
+            [Test]
+            public void Register_SingleCall_PreviewFilterRegistered()
+            {
+                PreviewGlobalFilters.Register();
+
+                CMSAssert.All(
+                    () => Assert.That(GlobalFilters.Filters.Count, Is.EqualTo(1)),
+                    () => Assert.That(GlobalFilters.Filters.First().Instance, Is.TypeOf(typeof(PreviewOutputCacheFilter)))
+                );
+            }
+
+
+            [Test]
+            public void Register_TwoCalls_PreviewFilterRegisteredOnlyOnce()
+            {
+                PreviewGlobalFilters.Register();
+                PreviewGlobalFilters.Register();
+
+                CMSAssert.All(
+                    () => Assert.That(GlobalFilters.Filters.Count, Is.EqualTo(1)),
+                    () => Assert.That(GlobalFilters.Filters.First().Instance, Is.TypeOf(typeof(PreviewOutputCacheFilter)))
+                );
+            }
+
+        }
+    }
+}