problem with RadCompression in Q2 build

[AgJeff]

I have ELMAH running on my server which reports and logs errors that might otherwise not be seen. Running on IIS 7 server fully patched. I have a web application that after I updated to the latest build (2009.1.527.35) starts throwing this error

System.Web.HttpException: Server cannot append header after HTTP headers have been sent.

Generated: Mon, 01 Jun 2009 18:55:13 GMT

System.Web.HttpException: Server cannot append header after HTTP headers have been sent.

   at System.Web.HttpResponse.AppendHeader(String name, String value)

   at Telerik.Web.UI.RadCompression.application_EndRequest(Object sender, EventArgs e)

   at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()

   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

[Bruno]

I think that this error may be caused by calling flush on the response. You may consider excluding the handler from compression module by overriding the module's  IsHttpCompressionEnabled method similar to the following:

public class MyModule: RadCompression
    {
        public override bool IsHttpCompressionEnabled()
        {
            if (HttpContext.Current.Handler is <YOUR_HANDLER_TYPE>)
            {
                return false;
            }
            return base.IsHttpCompressionEnabled();
        }
    }

-- Bruno

[AgJeff]

I don't believe this has anything to do with the handler because
1. it only happens on one page on the site
2. it worked without incident in all builds prior to this one

I only mention ELMAH because this is an error that most people would never know about and would not have seen. I only know about it because it's reported to me each time it happens

There is a rad rotator control on the page but nothing else of interest

[Rosen]

Hello,

Can you please check the latest internal build and see if the issue you are facing still exists? Please give it a try and let us know about the result.

Kind regards,
Rosen
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Check out the tips for optimizing your support resource searches.

[Gold Systems]

Hello,

We are currently experiencing the same issue, but I cannot confirm it was caused by the latest build.  We are fully updated, IIS7, Telerik version 2009.1.527.35.

Just curious if anything has come of this yet.

[AgJeff]

I have not yet tried the latest internal build - will wait for the release since it's not a show stopper. Thought I would mention that IIS compression is not turned on for this site.

[Sebastian]

Hello guys,

Follow the directions provided in Bruno's post and try the latest internal build from your accounts or the Q2 2009 (scheduled in the begging of the next month) to see whether this helps.
 
Kind regards,
Sebastian
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Check out the tips for optimizing your support resource searches.

[Kori]

We're also getting this issue quite often. Quite annoying, although nothing seems to be broken. ELMAH just returns the error every few minutes.

System.Web.HttpException: Server cannot append header after HTTP headers have been sent.
Generated: Fri, 11 Sep 2009 16:46:56 GMT

System.Web.HttpException: Server cannot append header after HTTP headers have been sent.
   at System.Web.HttpResponse.AppendHeader(String name, String value)
   at Telerik.Web.UI.RadCompression.application_EndRequest(Object sender, EventArgs e)
   at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Any suggestions? We're using RadControls Q2 2009, .NET 3.5 and Elmah.

[Sebastian]

Hello Kori,

Can you check whether this problem appears with the Q2 2009 SP1 release (2009.2.826) of RadControls for ASP.NET AJAX? If so, I suggest you isolate a simplified version of your project, exhibiting it, and send it enclosed to a standard support ticket. I will test/debug it locally an will get back to you with my findings.

Kind regards,
Sebastian
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.