如何解决“WebDriverException: Message: TypeError: can't access dead object"并等待使用 Selenium 和 Python 的框架可用 [英] How to address "WebDriverException: Message: TypeError: can't access dead object" and wait for a frame to be available using Selenium and Python

问题描述

我需要测试一个相当复杂的网页设置，其中包含嵌套框架.

I have a rather complex webpage setup I need to test, containing nested frames.

在实际问题中，selenium 代码正在加载包含框架的新网页内容，我想切换到该框架.为了避免任何显式等待，我尝试了以下代码片段:

In the actual problem the selenium code is loading new webpage contents containing a frame, which I want to switch to. In order to avoid any explicit waits, I tried the following code snippet:

self.driver.switch_to_default_content()
WebDriverWait(self.driver, 300).
        until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'frame1')))
WebDriverWait(self.driver, 300).
        until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'frame2')))

但是，此代码段总是失败并导致以下错误:

However, this snippet always fails and results in the following error:

  ...
  File "/home/adietz/Projects/Venv/nosetests/local/lib/python2.7/site-packages/selenium/webdriver/support/wait.py", line 71, in until
    value = method(self._driver)
  File "/home/adietz/Projects/Venv/nosetests/local/lib/python2.7/site-packages/selenium/webdriver/support/expected_conditions.py", line 247, in __call__
    self.frame_locator))
  File "/home/adietz/Projects/Venv/nosetests/local/lib/python2.7/site-packages/selenium/webdriver/support/expected_conditions.py", line 402, in _find_element
    raise e
WebDriverException: Message: TypeError: can't access dead object

但是，如果我另外使用 sleep:

However, if I use a sleep in addition:

time.sleep(30)
self.driver.switch_to_default_content()
WebDriverWait(self.driver, 300).
        until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'frame1')))
WebDriverWait(self.driver, 300).
        until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'frame2')))

selenium 能够在框架内找到框架并切换到它.看起来在错误情况下 selenium 切换到 'frame1' 而 'frame2' 尚未加载，但 'frame2' 已加载到 'frame1' 的其他实例中，或者 selenium 无法识别(可能是错误?).所以现在硒在一些frame1"中，并且由于某些原因没有意识到frame2"已被加载.

selenium is able to find the frame inside the frame and switch to it. It looks like in the error case selenium switches to 'frame1' while 'frame2' is not yet loaded, but 'frame2' gets loaded in some other instance of 'frame1', or not recognized by selenium (maybe a bug?). So now selenium is inside some 'frame1' and for some reasons does not realize that the 'frame2' has been loaded.

我可以解决这个问题的唯一方法(不使用长时间睡眠)是使用这段丑陋的代码:

The only way I can fix this (without using a long sleep) is by using this ugly piece of code:

    mustend = time.time() + 300
    while time.time() < mustend:
        try:
            self.driver.switch_to_default_content()
            self.driver.switch_to.frame(self.driver.find_element_by_id("frame1"))
            self.driver.switch_to.frame(self.driver.find_element_by_id("frame2"))               
            break
        except WebDriverException as e:
            self.log("Sleeping 1 sec")
            time.sleep(1)
    if time.time() > mustend:
        raise TimeoutException

因此，每当我收到 WebDriverException(死对象)时，我都会转到顶级框架并尝试切换到内部框架 - 逐帧.

So whenever I get a WebDriverException (dead object), I go to the top-level frame and try to switch to the inner frame - frame by frame.

还有其他方法可以尝试吗?

Is there any other approach I can try?

其他信息

• iframe 是嵌套的，即frame2"在frame1"内.

推荐答案

更好的方法是创建自己的 expected_condition.例如:

Better approach is to make your own expected_condition. For example:

class nested_frames_to_be_available_and_switch:
    def __init__(self, *args):
        """
        :param args: locators tuple of nested frames (BY.ID, "ID1"), (BY.ID, "ID2"), ...
        """
        self.locators = args

    def __call__(self, driver):
        try:
            for locator in self.locators:
                driver.switch_to.frame(driver.find_element(*locator))
        except WebDriverException:
            driver.switch_to_default_content()
            return False
        return True

WebDriverWait(driver, 300).until(nested_frames_to_be_available_and_switch((By.ID, 'frame1'), (By.ID, 'frame1')))

但也许没有必要……我需要看看你的 html DOM.

But maybe there is no need for that.. To tell so I need to see your html DOM.

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