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Home / Developer Network / Forums / Sitefinity 3.x: Bugs & Issues > Unable to generate etag from dependencies.

• J.Hoventer Master

  Posted on Feb 19, 2010 (permalink)

  When I updated the home page's Title value and saved the page I got the following exception:
  
  Exception information:
      Exception type: HttpException
      Exception message: Unable to generate etag from dependencies. One of the dependencies couldn't generate a unique id.
  
  Stack trace:    at System.Web.HttpCachePolicy.UpdateFromDependencies(HttpResponse response)
     at System.Web.HttpCachePolicy.UpdateCachedHeaders(HttpResponse response)
     at System.Web.HttpCachePolicy.GetCurrentSettings(HttpResponse response)
     at System.Web.Caching.OutputCacheModule.OnLeave(Object source, EventArgs eventArgs)
     at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
     at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
  
  I went back to the page and changed the value back to what it was. This corrected the problem.
  
  How do we make sure this doesn't happen in future?
  
  Regards,
  Jacques

  Reply

• Ivan Dimitrov Ivan Dimitrov

  Posted on Feb 22, 2010 (permalink)

  Hi J.Hoventer,
  
  ETags are GUIDs. In your case the Guid seems not to be generated or it is not valid due to some configuration( IIS , load balancer or some values for the ASP.NET caching) . It seems that you use  SlidingExpiration and  ASP.NET caching for pages where SetETagFromFileDependencies is called. This method  creates an ETag by combining the file names and last modified timestamps for all files on which the handler is dependent. ETag values are unique identifiers that are generated by the server and changed every time the object is modified.
  
  All the best,
  Ivan Dimitrov
  the Telerik team

  
  Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.

  Reply

• J.Hoventer Master

  Posted on Feb 23, 2010 (permalink)

  Hi Ivan, thanks for the response,
  
  But I must admit, I'm not sure what I should be doing about this. Is this a problem that can be sorted out, is this something caused by Asp.net or Sitefinity?
  
  Regards,
  Jacques

  Reply

• Radoslav Georgiev Radoslav Georgiev

  Posted on Feb 23, 2010 (permalink)

  Hello J.Hoventer,

  
  

  Thank you for getting back to us.

  
  

  Could you please try to turn off ETags for the website and see what the result would be. You can take a look at the following blog post for reference: IIS7 Deployments calls for ETag Usage Review if using, take a look at the last comment for insight on who to "disable" ETag.

  
  Best wishes,
  Radoslav Georgiev
  the Telerik team

  
  Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.

  Reply

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