Chrome无头下载pdf使用水豚和硒

我已经设置了我的无头chrome与以下和这对所有的测试不下载文件的作品。

download_path="#{Rails.root}/tmp/downloads"

Capybara.register_driver(:headless_chrome) do |app|
  caps = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: {
      prefs: {
        'download.default_directory' => download_path,
        "download.extensions_to_open" => "applications/pdf",
        'download.directory_upgrade' => true,
        'download.prompt_for_download' => false,
        'plugins.plugins_disabled' => ["Chrome PDF Viewer"]
      },
      binary: "/opt/google/chrome/google-chrome",
      args: %w[headless disable-gpu window-size=1920,1080]
    }
  )
  Capybara::Selenium::Driver.new(
    app,
    browser: :chrome,
    desired_capabilities: caps
  )
end

我已经读到,我应该发送一个命令到硒铬驱动程序,允许下载,但我不知道如何与我的设置。这就是我想做的,但我的设置(不是从我的代码库);

@driver = Selenium::WebDriver.for :chrome, options: options

bridge = @driver.send(:bridge)
path = '/session/:session_id/chromium/send_command'
path[':session_id'] = bridge.session_id
bridge.http.call(:post, path, cmd: 'Page.setDownloadBehavior',
                 params: {
                   behavior: 'allow',
                   downloadPath: download_path
                 })

如何在设置中访问selenium网桥以便发送此http调用?