Question

我正在使用如下所示的显式等待，以检查元素是否可点击。

WebDriverWait(driver, 30).until(
        expected_conditions.element_to_be_clickable((By.CSS_SELECTOR, "#search")))

但是我得到了错误

 <class 'selenium.common.exceptions.WebDriverException'>
Message: The command 'GET /session/.../displayed' was not found.

如果我使用time.sleep()可以正常工作，而不是显式等待。我已将safari驱动程序初始化为

from selenium.webdriver import Safari
driver = Safari()

这是stacktrace

  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/support/wait.py", line 71, in until
    value = method(self._driver)
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/support/expected_conditions.py", line 283, in __call__
    element = visibility_of_element_located(self.locator)(driver)
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/support/expected_conditions.py", line 127, in __call__
    return _element_if_visible(_find_element(driver, self.locator))
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/support/expected_conditions.py", line 147, in _element_if_visible
    return element if element.is_displayed() == visibility else False
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/remote/webelement.py", line 490, in is_displayed
    return self._execute(Command.IS_ELEMENT_DISPLAYED)['value']
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/remote/webelement.py", line 628, in _execute
    return self._parent.execute(command, params)
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/remote/webdriver.py", line 314, in execute
    self.error_handler.check_response(response)
  File "/Users/Library/Python/2.7/lib/python/site-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
WebDriverException: Message: The command 'GET /session/7.../displayed' was not found.

Answer 1

此错误消息...

 <class 'selenium.common.exceptions.WebDriverException'>
Message: The command 'GET /session/.../displayed' was not found.

...表示向/session/{session id}/element/{element id}/displayed发送 GET 请求失败。

显示的元素

根据WebDriver W3C Editor's Draft，element displayed算法为 boolean 状态，其中true表示元素已显示，并且{ {1}}表示该元素未显示。要计算元素上的状态，请调用false。如果这样做不会产生错误，请从此函数调用中返回返回值。否则，返回带有错误代码 未知错误的错误。

此功能通常对URI模板为

的GET请求公开

Call(bot.dom.isShown, null, element)

分析

您已调用：

/session/{session id}/element/{element id}/displayed

WebDriverWait(driver, 30).until(expected_conditions.element_to_be_clickable((By.CSS_SELECTOR, "#search")))类在内部调用element_to_be_clickable()，并定义为：

visibility_of_element_located()

现在，class element_to_be_clickable(object): """ An Expectation for checking an element is visible and enabled such that you can click it.""" def __init__(self, locator): self.locator = locator def __call__(self, driver): element = visibility_of_element_located(self.locator)(driver) if element and element.is_enabled(): return element else: return False类返回visibility_of_element_located()，其定义为：

_element_if_visible(_find_element(driver, self.locator))

同样，class visibility_of_element_located(object): """ An expectation for checking that an element is present on the DOM of a page and visible. Visibility means that the element is not only displayed but also has a height and width that is greater than 0. locator - used to find the element returns the WebElement once it is located and visible """ def __init__(self, locator): self.locator = locator def __call__(self, driver): try: return _element_if_visible(_find_element(driver, self.locator)) except StaleElementReferenceException: return False返回_element_if_visible()，其定义为：

element if element.is_displayed() == visibility else False

因此，由于def _element_if_visible(element, visibility=True): return element if element.is_displayed() == visibility else False的{{1}}条件失败，因此您将错误视为 if()请求对 element.is_displayed() == visibility 端点失败。

没有相关的 HTML 和先前的步骤，很难猜测确切的原因，但可能是以下两种情况之一：

原因

NoSuchElementException 的原因可能是以下之一：

您采用的定位器策略无法识别HTML DOM中的任何元素。
您采用的定位器策略无法识别该元素，因为该元素不在浏览器的Viewport中。
您采用的定位器策略可以识别元素，但由于存在属性 style =“ display：none;” 而不会显示。
您采用的定位器策略不能唯一标识 HTML DOM 中所需的元素，并且当前可以找到其他隐藏 / 不可见元素。
您要查找的 WebElement 位于GET标记内。

解决方案

解决 NoSuchElementException 的解决方案可以是以下任意一种：

采用一个Locator Strategy来唯一标识所需的 WebElement 。您可以借助开发人员工具（ Ctrl + Shift + I 或 F12 ），然后使用元素检查器。

在这里您将找到有关how to inspect element in selenium3.6 as firebug is not an option any more for FF 56?
使用execute_script()方法滚动查看元素，如下所示：
```
/session/{session id}/element/{element id}/displayed
```
在这里您将找到有关Scrolling to top of the page in Python using Selenium

如果元素具有属性 style =“ display：none;” ，请通过<iframe>方法删除该属性，如下所示：

elem = driver.find_element_by_xpath("element_xpath")
driver.execute_script("arguments[0].scrollIntoView();", elem)

要检查元素是否在executeScript()内，遍历 HTML 以找到相应的elem = driver.find_element_by_xpath("element_xpath") driver.execute_script("arguments[0].removeAttribute('style')", elem) elem.send_keys("text_to_send")标签和<iframe>所需的 iframe 通过以下两种方法之一：
```
<iframe>
```
在这里您可以找到有关How can I select a html element no matter what frame it is in in selenium?的详细讨论。

WebDriverException：消息：使用safaridriver和Selenium 3.13.0显式等待时找不到命令'GET /session/7.../displayed'

1 个答案:

显示的元素

分析

原因

解决方案