require 'active_support/concern' require 'active_support/inflector' module ActiveModel # == Active Model Conversions # # Handles default conversions: to_model, to_key, to_param, and to_partial_path. # # 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 # cm.to_path # => "contact_messages/contact_message" # module Conversion extend ActiveSupport::Concern # 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 key attributes if any is set, regardless # if the object is persisted or not. def to_key key = respond_to?(:id) && id key ? [key] : nil end # Returns a string representing the object's key suitable for use in URLs, # or nil if persisted? is false. def to_param persisted? ? to_key.join('-') : nil end # Returns a string identifying the path associated with the object. # ActionPack uses this to find a suitable partial to represent the object. def to_partial_path self.class._to_partial_path end module ClassMethods #:nodoc: # Provide a class level cache for the to_path. This is an # internal method and should not be accessed directly. def _to_partial_path #:nodoc: @_to_partial_path ||= begin element = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(self)) collection = ActiveSupport::Inflector.tableize(self) "#{collection}/#{element}".freeze end end end end end