如何使用Python在Selenium中截屏指定的WebElement

Question

我想截屏Selenium中的一个元素，根据文档，每个WebElement都有一个功能：

截图（文件名）

将当前元素的屏幕截图保存到PNG图像文件。如果有任何IOError，则返回False，否则返回True。在文件名中使用完整路径。

Args:filename：您希望将屏幕截图保存到的完整路径。这应该以一个简单的结尾。png扩展

用法：元素。截图（“/Screenshots/foo.png”）

但是，当我在程序中使用此功能时：

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from time import sleep


url='http://www.google.com'
browser = webdriver.Chrome()  
browser.get(url)
content = browser.find_element_by_id('searchform')
content.screenshot('/home/ding/Pictures/shot.png')

它会引发如下错误：

Traceback (most recent call last):

  File "<ipython-input-8-309cb404878d>", line 11, in <module>
    content.screenshot('/home/ding/Pictures/shot.png')

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/webelement.py", line 453, in screenshot
    png = self.screenshot_as_png

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/webelement.py", line 435, in screenshot_as_png
    return base64.b64decode(self.screenshot_as_base64.encode('ascii'))

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/webelement.py", line 425, in screenshot_as_base64
    return self._execute(Command.ELEMENT_SCREENSHOT)['value']

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/webelement.py", line 501, in _execute
    return self._parent.execute(command, params)

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 308, in execute
    self.error_handler.check_response(response)

  File "/home/ding/anaconda3/lib/python3.6/site-packages/selenium/webdriver/remote/errorhandler.py", line 165, in check_response
    raise exception_class(value)

WebDriverException: unknown command: session/efbca24571c5332230f4d032ae04787c/element/0.7487814861441955-1/screenshot

如何解决这个问题，并在Python中使用Selenium拍摄元素的屏幕截图？

Answer 1

导入其他库来编写文件在我看来很愚蠢。。。

使用内置的open：

button_element = self._driver.find_element_by_class_name("a-button-input")
with open("element.png", "wb") as elem_file:
    elem_file.write(button_element.screenshot_as_png)

亚马逊元素输出：

Answer 2

你需要用save_screenshot方法替换screenshot。所以

而不是：

content.screenshot('/home/ding/Pictures/shot.png')

使用：

content.save_screenshot('/home/ding/Pictures/shot.png')

Answer 3

这段代码非常适合在火狐浏览器中截取特定元素的屏幕截图。

from selenium import webdriver
import io
from PIL import Image

fox = webdriver.Firefox()
fox.get('http://stackoverflow.com/')
image = fox.find_element_by_id('hlogo').screenshot_as_png
imageStream = io.BytesIO(image)
im = Image.open(imageStream)
im.save(image_path)