Python Selenium three ways to wait

1. Forced wait
The first is also the most simple and rough one way is to force waiting for sleep (xx), the force of the Lightning, such as XX time, whether the bump can keep up with the speed, or has been early, must wait xx time.
Look at the code:

#-*-coding: utf-8-*-
from selenium import webdriver
from time import sleep
driver = webdriver.Firefox ()
driver.get (‘https://www.xuehu365.com’)
sleep (3) # Force to wait 3 seconds before executing the next step
print driver.current_url
driver.quit () 

This is called forced wait, regardless of whether your browser is loaded, the program will have to wait 3 seconds, 3 seconds to continue to execute the following code, as debugging is very useful, and sometimes can be in the code such as waiting, but not always use this kind of wait, too rigid, seriously affect program execution speed.

2. Hidden waiting
The second method is called the Hidden Wait, implicitly_wait (xx), the meaning of the hidden wait is: The flash and bump-man agreement, no matter where the flash to, all must wait for the bump man xx seconds, if the bump in this period of time to come, then two people immediately set off to play monsters, if the bump in the specified time, Then the flash himself, that nature will wait for you to throw an exception.
Look at the code:

#-*-coding: utf-8-*-
from selenium import webdriver
driver = webdriver.Firefox ()
driver.implicitly_wait (30) # implicit wait, wait up to 30 seconds
driver.get (‘https://www.xuehu365.com’)
print driver.current_url
driver.quit () 

The stealth wait is set to a maximum wait time, if the page load completes within the specified time, then the next step, otherwise wait until the time cutoff, and then perform the next step. Note Here is a disadvantage, that is, the program will always wait for the entire page to load complete, that is, generally you see the browser tab bar that small circle no longer go, will do the next step, but sometimes the page wants the element has been loaded completed, but because the individual JS and other things particularly slow, I still have to wait until the page is complete to perform the next step, and I want to wait for the element I want to come out and what to do next? There is a way, it depends on selenium provide another way of waiting--------explicit waiting wait.

What needs to be specifically explained is: The recessive waits for the whole driver the cycle all to have the function, so as long as set once can, I have seen someone to take the recessive wait as the sleep in use, walks everywhere to come ...

3. Explicit wait
The third method is the explicit wait, webdriverwait, with the class of until () and Until_not () methods, can be based on the conditions of judgment and flexibility to wait. Its main meaning is: The program every XX seconds to see a glance, if the condition is set up, then the next step, otherwise continue to wait until the maximum set time, and then throw timeoutexception.
Let's look at a code example:

#-*-coding: utf-8-*-
from selenium import webdriver
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
driver = webdriver.Firefox ()
driver.implicitly_wait (10) # Implicit wait and explicit wait can be used at the same time, but note that the longest wait time is the greater of
driver.get (‘https://xuehu365.com’)
locator = (By.LINK_TEXT, ‘CSDN’)
try:
WebDriverWait (driver, 20, 0.5) .until (EC.presence_of_element_located (locator))
print driver.find_element_by_link_text (‘CSDN’). get_attribute (‘href‘)
finally:
driver.close () 

In the example above, we set the implicit wait and explicit wait, in other operations, the implicit wait plays a decisive role in webdriverwait. The dominant wait plays a major role, but it is important to note that the longest wait time depends on the larger of the two, in this case, 20, if the implicit wait time > Dominant wait time, the maximum wait time for the sentence code is equal to the hidden wait time.

Python Selenium three ways to wait