How would you refactor this to make it more DRY

i have your typical nested resource pattern, and at most any resource
is one level deep… so for a model PurchaseOrder which is optionally
nested under Customer ive worked up this before_filter…

but the problem is, i have my parent class name hard coded into the
function… so i can either copy this to every controller (which i
really know in my heart cant be appropriate) or ask for some input…

now i know all about resource_controller and the make_resourceful
plugins… but they’re all a bit too magical and over the top for my
needs - as awesome as they may be.

anyhow… heres the function.

private
def load_parent
class_name = :customer
parent_sym = “#{class_name.to_s}_id”.to_sym
parent_class = class_name.to_s.classify.constantize

# if there is a customer_id in params then load it...
#if not return the current controllers class, constantized so i

can do things like
# @purchase_order = @parent.find(params[:id])
# in my actions and have it work regardless of the presence of a
parent or not.

@parent = params[parent_sym] ?
  parent_class.find(params[parent_sym]).send

(self.controller_name.tableize.to_sym) :
self.controller_name.classify.constantize
end