title: How/where to temporarily store ActiveRecord objects if not in session?
body: <p>I'm refactoring a Rails-based event registration application that has a checkout process that hits several ActiveRecord models.  Ideally, the objects should not be saved unless checkout is complete (payment is successfully processed).  I'm not entirely certain why it would be a bad thing to serialize these objects into the session temporarily, but I've read over and over that its bad mojo.  At least there's no risk of getting out of sync with existing records, as there won't be any existing records.</p>
  
  <p>My questions are:</p>
  
  <p>A) Is it still problematic to store records in the session even though they don't exist elsewhere?  Even if I modify a model, can't I kill all existing sessions?</p>
  
  <p>B) If it may cause problems, how should I temporarily store objects?  Should I save them and use a boolean flag to indicate permanent vs. temporary status?  Then cron a script to weed out stale temporary objects?</p>
  
  <p>Thoughts?</p>