getting "Object reference not set to an instance of an object" while generating a key

[gdegroot]

First thanks for this fabulous feature!

I'm using donut caching successfully for a while, but sometimes I receive an "Object reference not set to an instance of an object" at:

I guess cacheSettings is null. Do you have a clue where I can find a solution to this problem?

Thanks, Glenn

[jaandrews]

I'm also getting this error, but the reported line is different. Below is the trace of the error.

System.NullReferenceException: Object reference not set to an instance of an object.
   at DevTrends.MvcDonutCaching.KeyGenerator.GenerateKey(ControllerContext context, CacheSettings cacheSettings) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\KeyGenerator.cs:line 99
   at DevTrends.MvcDonutCaching.DonutOutputCacheAttribute.ExecuteCallback(ControllerContext context, Boolean hasErrors) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\DonutOutputCacheAttribute.cs:line 335
   at DevTrends.MvcDonutCaching.DonutOutputCacheAttribute.OnException(ExceptionContext filterContext) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\DonutOutputCacheAttribute.cs:line 157
   at System.Web.Mvc.ControllerActionInvoker.InvokeExceptionFilters(ControllerContext controllerContext, IList`1 filters, Exception exception)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__19(AsyncCallback asyncCallback, Object asyncState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.BeginInvokeAction(ControllerContext controllerContext, String actionName, AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.<BeginExecuteCore>b__1c(AsyncCallback asyncCallback, Object asyncState, ExecuteCoreState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.<BeginExecute>b__14(AsyncCallback asyncCallback, Object callbackState, Controller controller)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(AsyncCallback asyncCallback, Object asyncState, ProcessRequestState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I suspect that routeValues is null when I get this error, which happens when a potentially dangerous request is made. Here is the error message that precedes this error.

System.Web.HttpRequestValidationException (0x80004005): A potentially dangerous Request.QueryString value was detected from the client (sections="All<script>alert(12345)...").
   at System.Web.HttpRequest.ValidateString(String value, String collectionKey, RequestValidationSource requestCollection)
   at System.Web.HttpRequest.<>c__DisplayClass280_0.<ValidateHttpValueCollection>b__0(String key, String value)
   at System.Web.HttpValueCollection.EnsureKeyValidated(String key)
   at System.Web.HttpValueCollection.Get(String name)
   at System.Collections.Specialized.NameValueCollection.get_Item(String name)
   at DevTrends.MvcDonutCaching.KeyGenerator.GenerateKey(ControllerContext context, CacheSettings cacheSettings) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\KeyGenerator.cs:line 119
   at DevTrends.MvcDonutCaching.DonutOutputCacheAttribute.ExecuteCallback(ControllerContext context, Boolean hasErrors) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\DonutOutputCacheAttribute.cs:line 335
   at DevTrends.MvcDonutCaching.DonutOutputCacheAttribute.OnException(ExceptionContext filterContext) in C:\Users\moonpyk\Documents\Visual Studio 2013\Projects\MvcDonutCaching\DevTrends.MvcDonutCaching\DonutOutputCacheAttribute.cs:line 157
   at System.Web.Mvc.ControllerActionInvoker.InvokeExceptionFilters(ControllerContext controllerContext, IList`1 filters, Exception exception)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__19(AsyncCallback asyncCallback, Object asyncState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.BeginInvokeAction(ControllerContext controllerContext, String actionName, AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.<BeginExecuteCore>b__1c(AsyncCallback asyncCallback, Object asyncState, ExecuteCoreState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.<BeginExecute>b__14(AsyncCallback asyncCallback, Object callbackState, Controller controller)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(AsyncCallback asyncCallback, Object asyncState, ProcessRequestState innerState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
   at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)