Lightweight detector of mobile devices, OSs & browsers (Ruby)

mobile_detector.rb

class MobileDetector
  # pass request.env for Rails 3.2
  def initialize(headers)
    @headers = headers
  end

  def get_mobile_os
    regexps = {
      #mobile OSs
      'ios' => 'ip(hone|ad|od)',
      'android' => 'android',
      'webos' => '(web|hpw)os',
      'palmos' => 'palm(\s?os|source)',
      'windows' => 'windows (phone|ce)',
      'symbian' => 'symbian(\s?os|)|symbos',
      'bbos' => 'blackberry(.*?version\/\d+|\d+\/\d+)',
      'bada' => 'bada'
    }

    return nil unless @headers['HTTP_USER_AGENT']

    regexps.each do |name, re|
      return name.to_sym if @headers['HTTP_USER_AGENT'] =~ Regexp.new(re, Regexp::IGNORECASE)
    end

    nil
  end

  def mobile?
    regexps = {
      #mobile browsers
      'opera_mobile' => 'opera (mobi|mini)', # Opera Mobile or Mini
      'webkit_mobile' => '(android|nokia|webos|hpwos|blackberry).*?webkit|webkit.*?(mobile|kindle|bolt|skyfire|dolfin|iris)', # Webkit mobile
      'firefox_mobile' => 'fennec', # Firefox mobile
      'ie_mobile' => 'iemobile|windows ce', # IE mobile
      'netfront' => 'netfront|kindle|psp|blazer|jasmine', # Netfront
      'uc_browser' => 'ucweb' # UC browser
    }

    return nil unless @headers['HTTP_USER_AGENT']

    regexps.each do |name, re|
      return true if @headers['HTTP_USER_AGENT'] =~ Regexp.new(re, Regexp::IGNORECASE)
    end

    false
  end

  def desktop?
    !mobile?
  end
end