Append headers exception


I noticed that every time a spider or search engine bot stops at my site, I always get the error below in the log. Also, sometimes, not all the time, I get the same error when I browse the site myself:
Exception message: Server cannot append header after HTTP headers have been sent.
Exception source : mscorlib
Exception stack trace :
Server stack trace:
at System.Web.HttpResponse.AppendHeader(String name, String value)
at Miron.Web.MbCompression.EncodingManager.SetResponseEncodingType()
at Miron.Web.MbCompression.OutputCacheStorage.Excute(HttpContext context, String[] absoluteFiles, Minifier minify, Int32 versionHash, EncodingManager encodingMgr)
at Miron.Web.MbCompression.CompressionHandlerBase.ProcessRequest(HttpContext context)
at Miron.Web.MbCompression.JavaScriptCompressionHandler.ProcessRequest(HttpContext context)
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message reqMsg, Boolean bProxyCase)
at System.Runtime.Remoting.Proxies.RemotingProxy.Invoke(Object NotUsed, MessageData& msgData)
at System.Action`1.EndInvoke(IAsyncResult result)
at Miron.Web.MbCompression.CompressionHandlerBase.EndProcessRequest(IAsyncResult result)
at System.Web.HttpApplication.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)
Execution file path : /scripts/jslib.axd
Raw URL : /scripts/jslib.axd?d=StateCountyCityChooser.js&v=1
URL Referrer : http://www.vacationrentalslounge.com/default.aspx
User agent : Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/ Safari/532.5
Any idea what might be the problem? Is it possible that I am doing something in my code that interferes with the setting of the header, more specifically, according to the error, the EncodingType?
Thank you,


javierperez wrote Nov 1, 2010 at 5:45 PM

Did you get an answer to this problem? I am getting the same exceptions.


wrote Sep 7, 2011 at 8:32 AM

wrote Feb 14, 2013 at 2:04 AM