Throwing exception in Http Module's Init RSS

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  jamiebarrow

  Member

  10 Points

  8 Posts

  Throwing exception in Http Module's Init

  Aug 18, 2011 04:00 PM|LINK

  Hi,

  If an exception is thrown in the Init method of an Http Module, what are the expected consequences?

  I would like to catch an exception thrown in a different module, by a previously registered module. I'm using IIS 7/7.5.

  I've registered the modules as below:

  <system.webServer>
      <modules>
          <add name="ErrorHandlingHttpModule" type="ErrorHandlingHttpModule"/>
          <add name="ErrorCausingHttpModule" type="ErrorCausingHttpModule"/>
      </modules>
  </system.webServer>
  
  

  Which refer to the below (with details left out):

  public class ErrorHandlingHttpModule : IHttpModule
  {
      public void Init(HttpApplication Application)
      {
          Application.Error += new System.EventHandler(Application_Error);
      }
      void Application_Error(object sender, System.EventArgs e)
      {
          // handle error and transfer to a custom page
      }
  }

  public class ErrorCausingHttpModule:IHttpModule
  {
      public void Init(HttpApplication Application)
      {
          Application.Error += new System.EventHandler(Application_Error);
          throw new Exception("BANG");
      }
      void Application_Error(object sender, System.EventArgs e)
      {
      }
  }

  I ran the app in debug mode, with breakpoints set on all the methods & events and found that the Application_Error event never is reached in either module. Eventually causing the yellow screen of death.

  It appears then that if an exception is thrown in the Init method of an IHttpModule implementation, that the whole thing just crashes... is there no way to avoid the yellow screen of death in this case, and display a user friendly error page instead?

  Thanks,

  James

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  jamiebarrow

  Member

  10 Points

  8 Posts

  Re: Throwing exception in Http Module's Init

  Aug 18, 2011 04:02 PM|LINK

  And I guess more specifically, what is the process in loading an application's modules on IIS 7?

  If anyone has refrences describing the whole process/workflow/lifecycle in detail, it would be much appreciated.