python selenium的使用

*隐式等待

　　driver.implicitly_wait(time_to_wait)

　　当查找节点而节点并没有立即出现的时候，隐形等待一段时间直到元素被找到或命令完成，该命令在每个会话中仅需执行一次

In [5]: driver = webdriver.Chrome()

DevTools listening on ws://127.0.0.1:12823/devtools/browser/5e6b75be-748f-42e0-a726-02883e6ff2ef

In [6]: ?driver.implicitly_wait
Signature: driver.implicitly_wait(time_to_wait)
Docstring:
Sets a sticky timeout to implicitly wait for an element to be found,
   or a command to complete. This method only needs to be called one
   time per session. To set the timeout for calls to
   execute_async_script, see set_script_timeout.

:Args:
 - time_to_wait: Amount of time to wait (in seconds)

:Usage:
    driver.implicitly_wait(30)

*显示等待

先指定好某个要查找的节点，然后指定一个最长的等待时间，默认每0.5秒轮询一次，如果在规定时间内加载出来了这个节点，那就返回查找的节点，如果到了规定时间依然没有加载出该节点，则会抛出超时异常。

且在调用期间默认忽略NoSuchElementException异常，注解如下：

In [7]: from selenium.webdriver.support.ui import WebDriverWait

In [8]: ?WebDriverWait
Init signature: WebDriverWait(driver, timeout, poll_frequency=0.5, ignored_exceptions=None)
Docstring:      <no docstring>
Init docstring:
Constructor, takes a WebDriver instance and timeout in seconds.

:Args:
 - driver - Instance of WebDriver (Ie, Firefox, Chrome or Remote)
 - timeout - Number of seconds before timing out
 - poll_frequency - sleep interval between calls
   By default, it is 0.5 second.
 - ignored_exceptions - iterable structure of exception classes ignored during calls.
   By default, it contains NoSuchElementException only.

Example:
 from selenium.webdriver.support.ui import WebDriverWait

 element = WebDriverWait(driver, 10).until(lambda x: x.find_element_by_id("someId"))

 is_disappeared = WebDriverWait(driver, 30, 1, (ElementNotVisibleException)).\

             until_not(lambda x: x.find_element_by_id("someId").is_displayed())
File:           d:\anaconda3\lib\site-packages\selenium\webdriver\support\wait.py
Type:           type

例：

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
driver = webdriver.Chrome(chrome_options=option)
wait = WebDriverWait(driver, 5)
datarange = wait.until(EC.element_to_be_clickable((By.XPATH, '//*[@id="managed-accounts-view"]/div/div[1]/div/date-range-selector/div/div[1]/*'))) #节点可点击
datarange.click()

python selenium的使用

猜你喜欢