detect heavy assets

listup.rb

begin
  class Capybara::Poltergeist::NetworkTraffic::Response
    def stage
      @data['stage']
    end
  end

  poltergeist_drivers = Capybara
    .send(:session_pool)
    .each_value.map(&:driver)
    .select { |driver| driver.is_a? Capybara::Poltergeist::Driver }
  poltergeist_drivers.each do |driver|
    begin
      _window_handle = driver.browser.window_handle
      driver.browser.window_handles.each do |window_handle|
        driver.browser.switch_to_window window_handle

        network_traffics = []
        driver.network_traffic.each do |request|
          start_request = request.response_parts.find { |response_part| response_part.stage == 'start' }
          end_request = request.response_parts.find { |response_part| response_part.stage == 'end' }

          if start_request && end_request
            network_traffics << [request.url, end_request.time - start_request.time]
          else
            network_traffics << [request.url, 0]
          end
        end
        network_traffics.each do |t,u|
          puts "%03.03fsec:%s" % [u, t]
        end
      end
    ensure
      driver.browser.switch_to_window _window_handle
    end
  end
  nil
end