call a function for :condition in association

I want to display sent messages by the user. Problem is drafts and sent message contents are stored in the same table, so I want to put a condition on the following association from user.rb

has_many :sent_messages, :class_name => "Message", :foreign_key => "user_id",  :conditions => [#it has been sent!]

I thought of using a is_sent method from message.rb

def is_sent
    current_user开发者_StackOverflow.drafts.find_by_message_id(:first, self.id).empty?
end

How can i call this method in the :condition of my association? Would it be preferable to use a column in my Message table specifying if the stored message has been sent or not?

Thanks!

I would add a boolean sent column to Message, and use this condition in the has_many:

:conditions => { :sent => true }

This would also give you the function sent? in Message, eliminating your is_sent function. Note that using a question mark like that in function names in Ruby is common practice, and is_ is frowned upon.