module ActiveModel # == Active Model Conversions # # Handles default conversions: to_model, to_key and to_param. # # Let's take for example this non persisted object. # # class ContactMessage # include ActiveModel::Conversion # # # ContactMessage are never persisted in the DB # def persisted? # false # end # end # # cm = ContactMessage.new # cm.to_model == self # => true # cm.to_key # => nil # cm.to_param # => nil # module Conversion # If your object is already designed to implement all of the Active Model # you can use the default <tt>:to_model</tt> implementation, which simply # returns self. # # If your model does not act like an Active Model object, then you should # define <tt>:to_model</tt> yourself returning a proxy object that wraps # your object with Active Model compliant methods. def to_model self end # Returns an Enumerable of all key attributes if any is set, regardless # if the object is persisted or not. # # Note the default implementation uses persisted? just because all objects # in Ruby 1.8.x responds to <tt>:id</tt>. def to_key persisted? ? [id] : nil end # Returns a string representing the object's key suitable for use in URLs, # or nil if <tt>persisted?</tt> is false. def to_param persisted? ? to_key.join('-') : nil end end end