module ActiveModel # == Active Model Conversions # # Handles default conversions: to_model, to_key and to_param. # # == Example # # 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 to_model implementation, which simply returns # self. # # If your model does not act like an Active Model object, then you should # define :to_model yourself returning a proxy object that wraps # your object with Active Model compliant methods. def to_model self end # Returns an Enumerable of all (primary) key attributes or nil if # persisted? is false def to_key persisted? ? [id] : nil end # Returns a string representing the object's key suitable for use in URLs, # or nil if persisted? is false def to_param to_key ? to_key.join('-') : nil end end end