Module: Polymorpheus::Interface::ClassMethods

Defined in:
lib/polymorpheus/interface.rb

Instance Method Summary collapse

Instance Method Details

#belongs_to_polymorphic(*args) ⇒ Object 



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# File 'lib/polymorpheus/interface.rb', line 25

def belongs_to_polymorphic(*args)
  options = args.extract_options!
  polymorphic_api = options[:as]
  associations = args.collect(&:to_s).collect(&:downcase)
  association_keys = associations.collect{|association| "#{association}_id"}

  # Set belongs_to assocaitions
  associations.each do |associated_model|
    belongs_to associated_model.to_sym
  end

  # Class constant defining the keys
  const_set "#{polymorphic_api}_keys".upcase, association_keys

  # Helper methods and constants
  define_method "#{polymorphic_api}_types" do
    associations
  end

  define_method "#{polymorphic_api}_active_key" do
    keys = association_keys.select { |key| self.send(key).present? }
    keys.first if keys.length == 1
  end

  define_method "#{polymorphic_api}_query_condition" do
    fk = self.send("#{polymorphic_api}_active_key")
    { fk.to_s => self.send(fk) } if fk
  end

  # Getter method
  define_method polymorphic_api do
    if key = self.send("#{polymorphic_api}_active_key")
      # we are connecting to an existing item in the db
      self.send key.gsub(/_id$/,'')
    else
      # we can also link to a new record if we're careful
      objs = associations.map { |association| self.send(association) }.compact
      objs.first if objs.length == 1
     end
  end

  # Setter method
  define_method "#{polymorphic_api}=" do |polymorphic_obj|

    klass_ancestors = polymorphic_obj.class
                      .ancestors.map(&:name).compact.map(&:underscore)
    match = associations & klass_ancestors

    if match.blank?
      raise Polymorpheus::Interface::InvalidTypeError, associations
    elsif match.length > 1
      raise Polymorpheus::Interface::AmbiguousTypeError
    else
      accessor = "#{polymorphic_obj.class.base_class.name.underscore}_id="
      self.send(accessor, polymorphic_obj.id)
      (associations - match).each do |association_to_reset|
        self.send("#{association_to_reset}_id=", nil)
      end
    end
  end

  # Private method called as part of validation
  # Validate that there is exactly one associated object
  define_method "polymorphic_#{polymorphic_api}_relationship_is_valid" do
    if !self.send(polymorphic_api)
      self.errors.add(:base,
        "You must specify exactly one of the following: {#{associations.join(', ')}}")
    end
  end
  private "polymorphic_#{polymorphic_api}_relationship_is_valid"

end

#validates_polymorph(polymorphic_api) ⇒ Object 



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# File 'lib/polymorpheus/interface.rb', line 98

def validates_polymorph(polymorphic_api)
  validate "polymorphic_#{polymorphic_api}_relationship_is_valid"
end