Application Controller

application_controller.rb

before_filter :prepare_for_mobile

private

def mobile_device?
  if session[:mobile_param]
    session[:mobile_param] == "1"
  else
    request.user_agent =~ /Mobile|webOS/
  end
end
helper_method :mobile_device?

def prepare_for_mobile
  if request.format == 'text/html'
    session[:mobile_param] = params[:mobile] if params[:mobile]
    request.format = :mobile if mobile_device?
  end
end