Selenium Webdriver在chrome：// downloads上找不到元素

Question

我在python中将selenium与chromedriver一起使用。

我的问题是selenium导致我尝试访问chrome下载页面（chrome：// downloads）上的元素时出现错误。例如，我尝试获取文件URL“
http：//file.jpg ”。

<a id="url" target="_blank" href="http://file.jpg">http://file.jpg</a>

但是当我尝试通过其ID获取元素时，出现了异常。

码：

driver = webdriver.Chrome("chromedriver.exe")
driver.get("chrome://downloads/")
file_url = driver.find_element_by_id("url").get_attribute("href")

例外：

Traceback (most recent call last):
  File "<pyshell#34>", line 3, in <module>
    driver.find_element_by_id("url")
  File "D:\Python\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 269, in find_element_by_id
    return self.find_element(by=By.ID, value=id_)
  File "D:\Python\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 752, in find_element
    'value': value})['value']
  File "D:\Python\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 236, in execute
    self.error_handler.check_response(response)
  File "D:\Python\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 192, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"id","selector":"url"}
  (Session info: chrome=56.0.2924.87)
  (Driver info: chromedriver=2.27.440174 (e97a722caafc2d3a8b807ee115bfb307f7d2cfd9),platform=Windows NT 10.0.10586 x86_64)

通过javascript使用driver.execute_script()也不适合我。NoSuchElementException在浏览器中可以看到元素时，为什么会出现？

Answer 1

目标链接位于几个shadow-root块内。试试这个：

driver = webdriver.Chrome("chromedriver.exe")
driver.get("chrome://downloads/")

manager = driver.find_element_by_css_selector('body/deep/downloads-manager')
item = manager.find_element_by_css_selector('body/deep/downloads-item')
shadow = driver.execute_script('return arguments[0].shadowRoot;', item)
link = shadow.find_element_by_css_selector('div#title-area>a')

file_url = link.get_attribute("href")