method returns accessible attributes with inheritance and descendants

get_permitted_params.rb

def permitted_params(klass)
  self_attrs = klass.accessible_attributes.reject { |attr| attr =~ /_attributes$/ }.map(&:to_sym)
  nested_attrs = klass.nested_attributes_options.keys.map do |nested_klass|
    nested_const_klass = nested_klass.to_s.singularize.classify.constantize
    { "#{nested_klass}_attributes".to_sym => permitted_params(nested_const_klass) }
  end
  types_attrs = klass.descendants.map { |type_class| permitted_params(type_class) }
  (self_attrs + (types_attrs || []) + nested_attrs).flatten.uniq.compact
end