python - 将 while 语句与 WebDriverWait 和 Expected_conditions 一起使用

Question

我正在尝试使用 AJAX 和 jquery 处理网络。我想向下滚动直到到达某个部分，所以我用 wait 和 EC 做了一些方法，但没有成功，如下所示:

 scroll_bottom = """$('html, body').animate({scrollTop:$(document).height()},'fast');"""
 from selenium.webdriver.common.by import By
 # from selenium.webdriver.support.ui import WebDriverWait
 from selenium.webdriver.support import expected_conditions as EC
 # wait = WebDriverWait(driver,10)
 while EC.element_to_be_clickable((By.ID,"STOP_HERE")):
     driver.execute_script(scroll_bottom)

有什么方法可以处理等待和EC，以便在某些元素可见和/或可点击之前执行某些操作？

编辑:

我用 JavaScript 做了一些肮脏的把戏，但这绝对不是达到我的目标的 Pythonic 方式。

def scroll_b():
    from selenium.webdriver.common.by import By
    from selenium.webdriver.support.ui import WebDriverWait
    driver.execute_script(load_jquery)
    wait = WebDriverWait(driver,10)
    js = """return document.getElementById("STOP_HERE")"""
    selector = driver.execute_script(js)
    while not  selector :
        driver.execute_script(scroll_bottom)
        time.sleep(1)
        selector = driver.execute_script(js)
    print("END OF SCROLL")

Answer 1

这不是内置预期条件的工作方式。一般来说，一旦激活它们，它们就会阻塞，直到任何条件返回 True。

我认为你想要的是自定义的预期条件。这是未经测试的:

from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait

scroll_bottom = """$('html, body').animate({scrollTop:$(document).height()},'fast');"""

def scroll_wait(driver):
    # See if your element is present
    # Use the plural 'elements' to prevent throwing an exception
    # if the element is not yet present
    elem = driver.find_elements_by_id("STOP_HERE")

    # Now use a conditional to control the Wait
    if elem and elem[0].is_enabled and elem[0].is_displayed:
        # Returning True (or something that is truthy, like a non-empty list)
        # will cause the selenium Wait to exit
        return elem[0]
    else:
        # Scroll down more
        driver.execute_script(scroll_bottom)

        # Returning False will cause the Wait to wait and then retry
        return False

# Now use your custom expected condition with a Wait
TIMEOUT = 30  # 30 second timeout
WebDriverWait(driver, TIMEOUT, poll_frequency=0.25).until(scroll_wait)

这种方法的优点在于，它会在 30 秒(或者您设置的 TIMEOUT 的值)后抛出异常。