For some reason, sometimes routes values can be null.

Closes : #26, Refs: #19

Author: moonpyk

DevTrends.MvcDonutCaching/DonutOutputCacheAttribute.cs

@@ -144,6 +144,12 @@ public override void OnActionExecuting(ActionExecutingContext filterContext)
 
             var cacheKey = KeyGenerator.GenerateKey(filterContext, CacheSettings);
 
+            // If we are unable to generate a cache key it mean we can't do anything
+            if (string.IsNullOrEmpty(cacheKey))
+            {
+                return;
+            }
+
             // Are we actually storing data on the server side ?
             if (CacheSettings.IsServerCachingEnabled)
             {
@@ -302,6 +308,11 @@ private void ExecuteCallback(ControllerContext context, bool hasErrors)
         {
             var cacheKey = KeyGenerator.GenerateKey(context, CacheSettings);
 
+            if (string.IsNullOrEmpty(cacheKey))
+            {
+                return;
+            }
+
             var callback = context.HttpContext.Items[cacheKey] as Action<bool>;
 
             if (callback != null)

DevTrends.MvcDonutCaching/KeyGenerator.cs

@@ -23,17 +23,40 @@ public KeyGenerator(IKeyBuilder keyBuilder)
 
         public string GenerateKey(ControllerContext context, CacheSettings cacheSettings)
         {
-            var actionName     = context.RouteData.Values["action"].ToString();
-            var controllerName = context.RouteData.Values["controller"].ToString();
-            string areaName    = null;
+            var routeData = context.RouteData;
 
-            if (context.RouteData.DataTokens.ContainsKey("area"))
+            if (routeData == null)
             {
-                areaName = context.RouteData.DataTokens["area"].ToString();
+                return null;
+            }
+
+            string actionName = null,
+                controllerName = null;
+
+            if (routeData.Values["action"] != null)
+            {
+                actionName = routeData.Values["action"].ToString();
+            }
+
+            if (routeData.Values["controller"] != null)
+            {
+                controllerName = routeData.Values["controller"].ToString();
+            }
+
+            if (string.IsNullOrEmpty(actionName) || string.IsNullOrEmpty(controllerName))
+            {
+                return null;
+            }
+
+            string areaName = null;
+
+            if (routeData.DataTokens.ContainsKey("area"))
+            {
+                areaName = routeData.DataTokens["area"].ToString();
             }
 
             // remove controller, action and DictionaryValueProvider which is added by the framework for child actions
-            var filteredRouteData = context.RouteData.Values.Where(
+            var filteredRouteData = routeData.Values.Where(
                 x => x.Key.ToLowerInvariant() != "controller" && 
                      x.Key.ToLowerInvariant() != "action" &&   
                      x.Key.ToLowerInvariant() != "area" &&