title: How to retrieve an URL inside a .NET http handler?
body: <p>I'm hosting images on a server, within an ASP.NET application.
  I wrote a custom http handler that resizes the image and also increment "image_view_count" in a DB.</p>
  
  <p>Now, I would like to also do some logging to know where the image is used. For example:</p>
  
  <p>Image abc.jpg is on my server at www.myserver.com/stuff/abc.jpg
  Somebody uses it by linking it in a forum post located at www.forum.com/thread.php?id=1234</p>
  
  <p>I would like to retrieve the www.forum.com/thread.php?id=1234 URL in my http handler. When I use Request.Url.ToString(), in the previous example, I receive www.myserver.com/stuff/abc.jpg.</p>
  
  <p>How should I do this ? Is there an equivalent in managed code to location.href ?</p>