title: setting the filename for a downloaded file in a rails application
body: <p>I have a controller action that allows a user to download a file with an extension of .ppt . It's not really a powerpoint binary, just an xml-ish format that powerpoint can read. the file is downloaded from the show action of a controller called ElementsController, but the show action is not actually defined in the controller, there is, however, a template file for it in app/views/elements/show.ppt.builder .  I have the Mime::Type registered in config/initializers/mime_types.rb as such: </p>
  
  <p><code>Mime::Type.register "multipart/related", :ppt</code></p>
  
  <p>and the file downloads properly, and opens with powerpoint on a windows system, yet the problem is the filename.  the name of the file is 3.ppt where three is the id parameter in the url.  I would like to know if there is a way to set the filename to something a little more descriptive than 3.ppt.</p>
  
  <p>thx,</p>
  
  <p>-C</p>