Merge branch 'dev-v7' of https://github.com/umbraco/Umbraco-CMS into dev-v7

src/Umbraco.Web.UI.Client/src/views/content/edit.html

@@ -58,7 +58,7 @@
                </umb-button>
 
                <umb-button
-                  ng-if="!page.isNew"
+                  ng-if="!page.isNew && content.allowPreview"
                   type="button"
                   action="preview(content)"
                   label="Preview page"

src/Umbraco.Web/Models/ContentEditing/ContentItemDisplay.cs

@@ -20,6 +20,11 @@ namespace Umbraco.Web.Models.ContentEditing
     [DataContract(Name = "content", Namespace = "")]
     public class ContentItemDisplay : ListViewAwareContentItemDisplayBase<ContentPropertyDisplay, IContent>
     {
+        public ContentItemDisplay()
+        {
+            AllowPreview = true;
+        }
+
         [DataMember(Name = "publishDate")]
         public DateTime? PublishDate { get; set; }
 
@@ -34,7 +39,16 @@ namespace Umbraco.Web.Models.ContentEditing
 
         [DataMember(Name = "urls")]
         public string[] Urls { get; set; }
-        
+
+        /// <summary>
+        /// Determines whether previewing is allowed for this node
+        /// </summary>
+        /// <remarks>
+        /// By default this is true but by using events developers can toggle this off for certain documents if there is nothing to preview
+        /// </remarks>
+        [DataMember( Name = "allowPreview" )]
+        public bool AllowPreview { get; set; }
+
         /// <summary>
         /// The allowed 'actions' based on the user's permissions - Create, Update, Publish, Send to publish
         /// </summary>

src/Umbraco.Web/Models/Mapping/ContentModelMapper.cs

@@ -66,6 +66,7 @@ namespace Umbraco.Web.Models.Mapping
                             ? new[] {"Cannot generate urls without a current Umbraco Context"}
                             : content.GetContentUrls(UmbracoContext.Current)))
                 .ForMember(display => display.Properties, expression => expression.Ignore())
+                .ForMember(display => display.AllowPreview, expression => expression.Ignore())
                 .ForMember(display => display.TreeNodeUrl, expression => expression.Ignore())
                 .ForMember(display => display.Notifications, expression => expression.Ignore())
                 .ForMember(display => display.Errors, expression => expression.Ignore())

src/Umbraco.Web/Redirects/RedirectTrackingEventHandler.cs

@@ -93,6 +93,8 @@ namespace Umbraco.Web.Redirects
         {
             get
             {
+                if (UmbracoContext.Current == null)
+                    return null;
                 var oldRoutes = (Dictionary<int, Tuple<Guid, string>>) UmbracoContext.Current.HttpContext.Items[ContextKey3];
                 if (oldRoutes == null)
                     UmbracoContext.Current.HttpContext.Items[ContextKey3] = oldRoutes = new Dictionary<int, Tuple<Guid, string>>();
@@ -165,8 +167,11 @@ namespace Umbraco.Web.Redirects
 
         private void PageCacheRefresher_CacheUpdated(PageCacheRefresher sender, CacheRefresherEventArgs cacheRefresherEventArgs)
         {
-            var removeKeys = new List<int>();
+            if (OldRoutes == null)
+                return;
 
+            var removeKeys = new List<int>();
+            
             foreach (var oldRoute in OldRoutes)
             {
                 // assuming we cannot have 'CacheUpdated' for only part of the infos else we'd need