Removes IDisplayedContentItemHandler in favour of ICacheTagProvider (#7793)

Fixes #7792

src/Orchard.Web/Modules/Orchard.OutputCache/Filters/OutputCacheFilter.cs

@@ -20,7 +20,6 @@ using Orchard.OutputCache.Helpers;
 using Orchard.OutputCache.Models;
 using Orchard.OutputCache.Services;
 using Orchard.Services;
-using Orchard.Themes;
 using Orchard.UI.Admin;
 using Orchard.Utility.Extensions;
 
@@ -33,14 +32,12 @@ namespace Orchard.OutputCache.Filters {
         // Dependencies.
         private readonly ICacheManager _cacheManager;
         private readonly IOutputCacheStorageProvider _cacheStorageProvider;
-        private readonly ITagCache _tagCache;
-        private readonly IDisplayedContentItemHandler _displayedContentItemHandler;
         private readonly IWorkContextAccessor _workContextAccessor;
-        private readonly IThemeManager _themeManager;
         private readonly IClock _clock;
         private readonly ICacheService _cacheService;
         private readonly ISignals _signals;
         private readonly ShellSettings _shellSettings;
+        private readonly IEnumerable<ICacheTagProvider> _cacheTagProviders;
         private readonly ICachingEventHandler _cachingEvents;
         private bool _isDisposed = false;
 
@@ -49,26 +46,22 @@ namespace Orchard.OutputCache.Filters {
         public OutputCacheFilter(
             ICacheManager cacheManager,
             IOutputCacheStorageProvider cacheStorageProvider,
-            ITagCache tagCache,
-            IDisplayedContentItemHandler displayedContentItemHandler,
             IWorkContextAccessor workContextAccessor,
-            IThemeManager themeManager,
             IClock clock,
             ICacheService cacheService,
             ISignals signals,
             ShellSettings shellSettings,
+            IEnumerable<ICacheTagProvider> cacheTagProviders,
             ICachingEventHandler cachingEvents) {
 
             _cacheManager = cacheManager;
             _cacheStorageProvider = cacheStorageProvider;
-            _tagCache = tagCache;
-            _displayedContentItemHandler = displayedContentItemHandler;
             _workContextAccessor = workContextAccessor;
-            _themeManager = themeManager;
             _clock = clock;
             _cacheService = cacheService;
             _signals = signals;
             _shellSettings = shellSettings;
+            _cacheTagProviders = cacheTagProviders;
             _cachingEvents = cachingEvents;
 
             Logger = NullLogger.Instance;
@@ -206,8 +199,17 @@ namespace Orchard.OutputCache.Filters {
                 var cacheDuration = _cacheRouteConfig != null && _cacheRouteConfig.Duration.HasValue ? _cacheRouteConfig.Duration.Value : CacheSettings.DefaultCacheDuration;
                 var cacheGraceTime = _cacheRouteConfig != null && _cacheRouteConfig.GraceTime.HasValue ? _cacheRouteConfig.GraceTime.Value : CacheSettings.DefaultCacheGraceTime;
 
-                // Include each content item ID as tags for the cache entry.
-                var contentItemIds = _displayedContentItemHandler.GetDisplayed().Select(x => x.ToString(CultureInfo.InvariantCulture)).ToArray();
+                // Get the tags for this cache item from.
+                var cacheItemTags = new List<string>();
+
+                foreach (var cacheTagProvider in _cacheTagProviders) {
+                    try {
+                        cacheItemTags.AddRange(cacheTagProvider.GetTags());
+                    }
+                    catch (Exception ex) {
+                        Logger.Warning(ex, "Cache tags from provider {0} will not be added to the cached item ({1}) because the provider threw an exception when asked to provide tags.", cacheTagProvider.GetType().FullName, _cacheKey);
+                    }
+                }
 
                 // Capture the response output using a custom filter stream.
                 var response = filterContext.HttpContext.Response;
@@ -248,7 +250,7 @@ namespace Orchard.OutputCache.Filters {
                                 Url = filterContext.HttpContext.Request.Url.AbsolutePath,
                                 Tenant = scope.Resolve<ShellSettings>().Name,
                                 StatusCode = response.StatusCode,
-                                Tags = new[] { _invariantCacheKey }.Union(contentItemIds).ToArray(),
+                                Tags = new[] { _invariantCacheKey }.Union(cacheItemTags.Distinct()).ToArray(),
                                 ETag = etag
                             };
 

src/Orchard.Web/Modules/Orchard.OutputCache/Handlers/DisplayedContentCacheTagProvider.cs

@@ -1,26 +1,23 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Globalization;
 using System.Linq;
 using Orchard.OutputCache.Services;
 using Orchard.ContentManagement.Handlers;
 
 namespace Orchard.OutputCache.Handlers {
     /// <summary>
-    /// Saves references to content items which have been displayed during a request
+    /// Creates tags for content items which have been displayed during a request
     /// </summary>
-    public class DisplayedContentItemHandler : ContentHandler, IDisplayedContentItemHandler {
+    public class DisplayedContentCacheTagProvider : ContentHandler, ICacheTagProvider {
         private readonly Collection<int> _itemIds = new Collection<int>();
 
         protected override void BuildDisplayShape(BuildDisplayContext context) {
             _itemIds.Add(context.Content.Id);
         }
 
-        public bool IsDisplayed(int id) {
-            return _itemIds.Contains(id);
-        }
-
-        public IEnumerable<int> GetDisplayed() {
-            return _itemIds.Distinct();
+        public IEnumerable<string> GetTags() {
+            return _itemIds.Distinct().Select(id => id.ToString(CultureInfo.InvariantCulture));
         }
     }
 }

src/Orchard.Web/Modules/Orchard.OutputCache/ICachingEventHandler.cs

@@ -1,9 +1,5 @@
 using Orchard.Events;
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using System.Text;
-using System.Web;
 
 namespace Orchard.OutputCache {
     public interface ICachingEventHandler : IEventHandler {

src/Orchard.Web/Modules/Orchard.OutputCache/Orchard.OutputCache.csproj

@@ -128,7 +128,7 @@
     <Compile Include="Filters\CaptureStream.cs" />
     <Compile Include="Filters\OutputCacheFilter.cs" />
     <Compile Include="Handlers\CacheSettingsPartHandler.cs" />
-    <Compile Include="Handlers\DisplayedContentItemHandler.cs" />
+    <Compile Include="Handlers\DisplayedContentCacheTagProvider.cs" />
     <Compile Include="DatabaseOutputCacheMigrations.cs" />
     <Compile Include="Helpers\OutputCacheAttributeExtensions.cs" />
     <Compile Include="Migrations.cs" />
@@ -144,7 +144,7 @@
     <Compile Include="Services\DefaultCacheControlStrategy.cs" />
     <Compile Include="Services\DefaultTagCache.cs" />
     <Compile Include="Services\ICacheControlStrategy.cs" />
-    <Compile Include="Services\IDisplayedContentItemHandler.cs" />
+    <Compile Include="Services\ICacheTagProvider.cs" />
     <Compile Include="Services\ITagCache.cs" />
     <Compile Include="Services\DefaultCacheStorageProvider.cs" />
     <Compile Include="Services\ICacheService.cs" />

src/Orchard.Web/Modules/Orchard.OutputCache/Services/ICacheTagProvider.cs

@@ -0,0 +1,7 @@
+using System.Collections.Generic;
+
+namespace Orchard.OutputCache.Services {
+    public interface ICacheTagProvider : IDependency {
+        IEnumerable<string> GetTags();
+    }
+}

src/Orchard.Web/Modules/Orchard.OutputCache/Services/IDisplayedContentItemHandler.cs

@@ -1,9 +0,0 @@
-using System.Collections.Generic;
-using Orchard;
-
-namespace Orchard.OutputCache.Services {
-    public interface IDisplayedContentItemHandler : IDependency {
-        bool IsDisplayed(int id);
-        IEnumerable<int> GetDisplayed();
-    }
-}