title: Apache sub-route/symlink exceptions-to-the-rule
body: <p>I don't know how to describe this problem without a specific setup, so I'm not sure if the post title is very meaningful.</p>
  
  <p>Anyway, we have a Rails app called <code>marketing</code> running on Phusion Passenger.  We have the Passenger <code>VirtualHost</code> set up with a <code>RailsBaseURI /marketing</code> entry, and the <code>/var/www/html/marketing</code> symlink that points to the Rails directory in a separate part of the file system (say <code>/home/user1/marketing</code>).  This all works fine, and we can hit the app at <code>ourdomain.com/marketing</code>.  The Rails app has a couple of routes like <code>/marketing/businesses</code> and <code>/marketing/certificates</code> that point to different "subapps" corresponding to various functionalities of our marketing division.</p>
  
  <p>Now, I have a standalone Adobe AIR app called <code>MarketingPeanuts</code> that supports the AIR autoupdate feature.  In short, the autoupdate requires the AIR installer package and a config file on the server ("autoupdate contents"), and the AIR application code points to this URL.  I would like the URL for the autoupdate to be <code>ourdomain.com/marketing/peanuts</code> to maintain semantics.  However, I do not want to put the autoupdate contents into the Rails directory because 1) the <code>MarketingPeanuts</code> AIR app is not related in any way to the Rails app (other than being another function of the marketing division), and 2) any time I need to update the AIR app, I would have to redeploy the Rails app just to get the most recent autoupdate contents onto the server.</p>
  
  <p>So what I want to do is put the AIR autoupdate contents in a completely different part of the filesystem (say <code>/home/user2/marketing_peanuts</code>), and somehow tell Apache that if it sees the specific sub-URL <code>/marketing/peanuts</code>, point to this location, otherwise, send all other <code>/marketing/*</code> sub-URLs to the Rails directory (<code>/home/user1/marketing</code> from above).  All while not having Rails complain about the non-existent route (although if Apache can solve this problem, then the Rails problem shouldn't even exist).</p>
  
  <p>Is it possible to do this kind of thing in Apache (I'm guessing yes), and if yes, how?</p>