HTML sanitize while preserving entities

sanitize.rb

    def sanitize_html text
      escaped_text = text.gsub("&", "%AMP%")
      sanitized = Sanitize.fragment(escaped_text, Sanitize::Config::BASIC).split("\n")
      while sanitized.size > 0 && sanitized[0].blank?
        sanitized.shift
      end
      while sanitized.size > 0 && sanitized[-1].blank?
        sanitized.pop
      end
      return sanitized.join("\n").strip.gsub("%AMP%", '&')
    end