Don't wait for a page to load using Selenium i

问题:

How do I make selenium click on elements and scrape data before the page has fully loaded? My internet connection is quite terrible so it sometimes takes forever to load the page entirely, is there anyway around this?

回答1:

ChromeDriver 77.0 (which supports Chrome version 77) now supports eager as pageLoadStrategy.

Resolved issue 1902: Support eager page load strategy [Pri-2]

---

As you question mentions of click on elements and scrape data before the page has fully loaded in this case we can take help of an attribute pageLoadStrategy. When Selenium loads a page/url by default it follows a default configuration with pageLoadStrategy set to normal. Selenium can start executing the next line of code from different Document readiness state. Currently Selenium supports 3 different Document readiness state which we can configure through the pageLoadStrategy as follows:

1. none (undefined)
2. eager (page becomes interactive)
3. normal (complete page load)

Here is the code block to configure the pageLoadStrategy:

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

binary = r'C:\Program Files\Mozilla Firefox\firefox.exe'
caps = DesiredCapabilities().FIREFOX
# caps["pageLoadStrategy"] = "normal"  #  complete
caps["pageLoadStrategy"] = "eager"  #  interactive
# caps["pageLoadStrategy"] = "none"   #  undefined
driver = webdriver.Firefox(capabilities=caps, firefox_binary=binary, executable_path="C:\\Utility\\BrowserDrivers\\geckodriver.exe")
driver.get("https://google.com")

回答2:

For Chromedriver it works the same as in @DebanjanB's answer, however the 'eager' page load strategy is not yet supported

So for chromedriver you get:

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

caps = DesiredCapabilities().CHROME
# caps["pageLoadStrategy"] = "normal"  #  Waits for full page load
caps["pageLoadStrategy"] = "none"   # Do not wait for full page load
driver = webdriver.Chrome(desired_capabilities=caps, executable_path="path/to/chromedriver.exe")

Note that when using the 'none' strategy you most likely have to implement your own wait method to check if the element you need is loaded.

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

WebDriverWait(driver, timeout=10).until(
    ec.visibility_of_element_located((By.ID, "your_element_id"))
)

Now you can start interacting with your element before the page is fully loaded!