Question

It looks like association extensions have changed quite a bit throughout Rails 3.x.

I need to access the proxy owner and the proxy target (i.e, the has_many object and the belongs_to object).

The most recent documentation says To use proxy_association.owner and proxy_association.target. However, this throws an method missing. I found some older references (can’t find them now), saying that self.proxy_target would work. However this only seems to work intermittently and isn’t reliable between my local environment and production (strange… I know).

Does anybody know where I can find more definitive answer on how to access the owner and target from within an association extension using Rails 3.0.10?

Answer 1

proxy_association is new in rails 3.1. The rails 3.0.x (and 2.x) equivalent is proxy_owner and proxy_target. However proxy_target returns the instance variable that caches the association if it has been loaded, i.e. if the association has not yet been loaded you’d get back [] for a collection association. Or in other words, given

class Bar < ActiveRecord::Base
  has_many :foos do
    def target_test
      proxy_target
    end
  end
end

then

bar = Bar.first
bar.foos.target_test #=> []
bar.foos.inspect
bar.foos.target_test #=> [#<Foo id: 1 ...>]

You can force the target to be loaded by calling load_target before calling proxy_target. That all set I’m not sure why this is important – if you call stuff on self it will be forwarded to the target for you