Rails 4: scrubber with customizeable lists of allowed tags and attributes, based on :strip from Loofah gem

allowed_tags_scrubber.rb

# place this file to app/scrubbers/ directory
#
# This scrubber is analog of :strip build-in scrubber 
#  (http://rubydoc.info/github/flavorjones/loofah/master/Loofah/Scrubbers/Strip)
# with allowed @tags and @attributes lists.
# Fallback to default :strip behavior included.

class AllowedTagsScrubber < Loofah::Scrubber
  def initialize(options={})
    @direction = :bottom_up
    @tags = options[:tags]
    @attributes = options[:attributes]
  end
  
  def scrub(node)
    scrub_node_attributes(node) and return CONTINUE if node_allowed?(node)
    node.before node.children
    node.remove
  end
  
  private
  
  def scrub_node_attributes(node)
    fallback_scrub_node_attributes(node) and return true unless @attributes.present? && @attributes.respond_to?(:include?)
    node.attribute_nodes.each do |attr_node|
      attr_node.remove unless @attributes.include?(attr_node.name)
    end
  end
  
  def allowed_not_element_node_types
    [ Nokogiri::XML::Node::TEXT_NODE, Nokogiri::XML::Node::CDATA_SECTION_NODE ]
  end
  
  def fallback_scrub_node_attributes(node)
    Loofah::HTML5::Scrub.scrub_attributes(node)
  end
  
  def fallback_allowed_element_detection(node)
    Loofah::HTML5::Scrub.allowed_element?(node.name)
  end
  
  def node_allowed?(node)
    return fallback_allowed_element_detection(node) unless @tags.present? && @tags.respond_to?(:include?)
    return true if allowed_not_element_node_types.include?(node.type)
    return false unless node.type == Nokogiri::XML::Node::ELEMENT_NODE
    @tags.include? node.name
  end

end

application_helper.rb

module ApplicationHelper
...
  def sanitize(string, options)
    Loofah.fragment(string).scrub!(AllowedTagsScrubber.new(options)).to_s
  end
...
end

scrubbers_autoload.rb

# place this file to config/initializers/ directory
Rails.application.config.autoload_paths += [ Rails.root.join('app', 'scrubbers') ]