help with extensions

I am working with extensions to has_many associations, and I want to create a finder method that is conditional on the attributes of the object whose association I’m working with.

So, to use the example from the Agile Web Development: the authors show on pg 340 in the second edition how to pass an argument to a finder method. But I want to know if it’s possible to instead have the finder method look at attributes of the object on which the finder method is ultimately being executed (here, user) to determine the conditions.

class User

has_many :reading has_many :articles, :through => :readings do def rated_at_or_above(rating) # this is the finder method in AWD – works fine find :all, :conditions => [‘rating >= ?’, rating] end def rated_at_or_above_threshold # but can I do something like this? (doesn’t work) find :all, :conditions => [‘rating >= ?’, user.threshold] # NoMethodError: undefined method user for Article:class


end end

How would I implement this? As the error suggests, the problem is that the article doesn’t know who its user is. So how can I pass that information to this method, given that it’s nested inside of this association?


(Btw, I tried to post this yesterday but it has not appeared, and another msg suggested that posts made from the Google Groups page get lost sometimes – sorry if this is double-posted.)