使用硒的 chromedriver 中的节流 CPU

Question

所以我尝试在下面的selenium chromedriver 设置中添加CPUThrottlingRate。

require 'webdrivers/chromedriver'

module ChromeBrowser
  class << self

    def headless(throttling)
      @browser ||= headless_chrome_browser(throttling || 'regular')
    end

    private

    def headless_chrome_browser(throttling)
      options = Selenium::WebDriver::Chrome::Options.new

      # -> https://peter.sh/experiments/chromium-command-line-switches/#profiler-timing
      options.add_argument '--ignore-certificate-errors'
      # options.add_argument "--user-agent=#{random_user_agent}" # set Random User Agent
      options.add_argument '--allow-insecure-localhost'
      options.add_argument '--window-size=1400x1400'
      options.add_argument '--disable-gpu'
      options.add_argument '--disable-dev-shm-usage'
      options.add_argument '--noerrdialogs' # Suppresses all error dialogs when present
      options.add_argument '--profiler-timing=0' # whether chrome will contain timing information
      options.add_argument '--disable-infobars' # prevent infobars from appearing
      options.add_argument '--headless' if Rails.env.production? # headless on chrome
      # options.add_argument '--blink-settings=imagesEnabled=false' # disable images
      options.add_argument '--no-referrers' # don't send HTTP-Referer headers
      options.add_argument '--disable-breakpad' # disables the crash reporting
      options.add_argument '--disable-demo-model' # disables the chrome OS demo
      options.add_argument '--disable-translate' # disable google translate
      options.add_argument '--dns-prefetch-disable' # disable DNS prefetching
      options.add_argument '--no-pings' # no hyperlink auditing pings

      browser = Selenium::WebDriver.for :chrome, options: options

      case throttling
      when 'slow'
        browser.network_conditions = {
          offline: false,
          latency: 50,
          download_throughput: 51200,
          upload_throughput: 51200
        }
      when 'regular'
        browser.network_conditions = {
          offline: false,
          latency: 30,
          download_throughput: 51200,
          upload_throughput: 512000
        }
      when 'fast'
        browser.network_conditions = {
          offline: false,
          latency: 20,
          download_throughput: 1024000,
          upload_throughput: 1024000
        }
      end

      return browser
    end
  end
end

我在这里寻找 this 解决方案，但使用 ruby​​。

## rate 1 is no throttle, 2 is 2x slower, etc. 
driver.execute_cdp_cmd("Emulation.setCPUThrottlingRate", {'rate': 10})

• developertools 已安装
• running on chromedriver v92

我正在尝试同时限制网络速度和 CPU 以模拟 ~kinda~ 现实生活中的请求。

似乎无法弄清楚，我错过了什么？有用的链接：

• https://www.selenium.dev/documentation/support_packages/chrome_devtools/
• CPU throttling in chrome via python selenium
• https://github.com/SeleniumHQ/selenium/wiki/Ruby-Bindings

---

我试过了：

...
browser = Selenium::WebDriver.for :chrome, options: options
devToolsSession = browser.devtools
devToolsSession.send_cmd('Emulation.setCPUThrottlingRate', {rate: 10})

哪个产生

ArgumentError: wrong number of arguments (given 2, expected 1)
from /Users/minijohn/.asdf/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/selenium-webdriver-4.0.3/lib/selenium/webdriver/devtools.rb:55:in `send_cmd'

只有一个参数

Selenium::WebDriver::Error::WebDriverError: -32602: Invalid parameters: Failed to deserialize params.rate - BINDINGS: mandatory field missing at position 7
from /Users/minijohn/.asdf/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/selenium-webdriver-4.0.3/lib/selenium/webdriver/devtools.rb:69:in `send_cmd'

也试过了

browser = Selenium::WebDriver.for :chrome, options: options
browser.send_cmd('Emulation.setCPUThrottlingRate', {rate: 10})

产生

NoMethodError: undefined method `send_cmd' for #<Selenium::WebDriver::Chrome::Driver:0x2738339e1fe77884 browser=:chrome>
from (pry):14:in `headless_chrome_browser'

Answer 1

Selenium 的目标是定义浏览器供应商将在 WebDriver BiDi 规范中支持的常用命令，并通过简单的 API 支持它们，该 API 可通过 Driver#devtools 方法访问。

同时，任何 Chrome DevTools 命令都可以通过Driver#execute_cdp 执行。

在这种情况下，它看起来像：

SL-1495:code titusfortner$ irb
irb(main):001:0> require 'selenium-webdriver'
=> true
irb(main):002:0> driver = Selenium::WebDriver.for :chrome
=> #<Selenium::WebDriver::Chrome::Driver:0x..fc42365c4d30079b0 browser=:chrome>
irb(main):003:0> driver.execute_cdp('Emulation.setCPUThrottlingRate', rate: 10)
=> {}
irb(main):004:0> 

这里的关键是，在 Ruby 中，我们为此使用关键字而不是 Hash，而在 Ruby 3 中，它们现在的处理方式有所不同。