selenium（2） wait & page objects

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

driver = webdriver.Firefox()
driver.get("http://somedomain/url_that_delays_loading")
try:
    element = WebDriverWait(driver, 10).until(    //使用 WebDriverWait()来等待  最多等10秒来等待找到指定条件的元素， 超时未找到抛出TimeoutException
        EC.presence_of_element_located((By.ID, "myDynamicElement"))
    )
finally:
    driver.quit()

其他的EC方法用于自动化浏览器

title_is
title_contains
presence_of_element_located
visibility_of_element_located
visibility_of
presence_of_all_elements_located
text_to_be_present_in_element
text_to_be_present_in_element_value
frame_to_be_available_and_switch_to_it
invisibility_of_element_located
element_to_be_clickable
staleness_of
element_to_be_selected
element_located_to_be_selected
element_selection_state_to_be
element_located_selection_state_to_be
alert_is_present

例如：

from selenium.webdriver.support import expected_conditions as EC

wait = WebDriverWait(driver, 10)
element = wait.until(EC.element_to_be_clickable((By.ID, 'someid')))

也可创建自定义等待条件。可以使用带有__call__方法的类创建自定义等待条件，当条件不匹配时，该方法将返回False。

 1 class element_has_css_class(object):  //自定义的方法
 2   """An expectation for checking that an element has a particular css class.
 3 
 4   locator - used to find the element
 5   returns the WebElement once it has the particular css class
 6   """
 7   def __init__(self, locator, css_class):
 8     self.locator = locator
 9     self.css_class = css_class
10 
11   def __call__(self, driver):
12     element = driver.find_element(*self.locator)   # Finding the referenced element
13     if self.css_class in element.get_attribute("class"):
14         return element
15     else:
16         return False
17 
18 # Wait until an element with id='myNewInput' has class 'myCSSClass'
19 wait = WebDriverWait(driver, 10)
20 element = wait.until(element_has_css_class((By.ID, 'myNewInput'), "myCSSClass"))  // 先通过 init方法 call 方法

3.默认等待

1 from selenium import webdriver
2 
3 driver = webdriver.Firefox()
4 driver.implicitly_wait(10) # seconds
5 driver.get("http://somedomain/url_that_delays_loading")
6 myDynamicElement = driver.find_element_by_id("myDynamicElement")