Rails 3: How to identify after_commit action in observers? (create/update/destroy)

Question

I have an observer and I register an after_commit callback. How can I tell whether it was fired after create or update? I can tell an item was destroyed by asking

Answer 1

This is similar to your 1st approach but it only uses one method (before_save or before_validate to really be safe) and I don't see why this would override any value

class ItemObserver
  def before_validation(item) # or before_save
    @new_record = item.new_record?
  end

  def after_commit(item)
    @new_record ? do_this : do_that
  end
end

Update

This solution doesn't work because as stated by @eleano, ItemObserver is a Singleton, it has only one instance. So if 2 Item are saved at the same time @new_record could take its value from item_1 while after_commit is triggered by item_2. To overcome this problem there should be an item.id checking/mapping to "post-synchornize" the 2 callback methods : hackish.