Pycharm：使用 Python 的 Selenium：无法使用无头 chrome 找到 Web 元素

Question

当我使用 headless chrome 运行以下代码时，我在识别元素时遇到了问题。通过使用 head full 模式注释以下行，相同的代码运行良好。

# chrome_options.add_argument('--headless')

# chrome_options.add_argument('--disable-gpu')

测试详情：

操作系统： Windows10

ChromeDriver： 75.0.3770.8

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

chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument('--headless')
chrome_options.add_argument('--disable-gpu')
driver = webdriver.Chrome(ChromeDriverManager().install(), options=chrome_options)
wait = WebDriverWait(driver,30)
driver.maximize_window()
driver.get('https://learn.letskodeit.com/')
print(driver.title)
wait.until(EC.element_to_be_clickable((By.LINK_TEXT, 'Login'))).click()
wait.until(EC.visibility_of_element_located((By.ID, 'user_email'))).send_keys("test@email.com")
wait.until(EC.visibility_of_element_located((By.ID, 'user_password'))).send_keys("abcabc")
wait.until(EC.visibility_of_element_located((By.NAME, 'commit'))).click()
print(driver.title)
driver.close()
driver.quit()

输出：

"C:\Program Files (x86)\Python37-32\python.exe" C:/PycharmProjects/seleniumwd2/basics/RunHeadlessChromeTests.py

Checking for win32 chromedriver:75.0.3770.8 in cache
Driver found in C:\Users\vishr\.wdm\chromedriver\75.0.3770.8\win32/chromedriver.exe
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Traceback (most recent call last):
  File "C:/PycharmProjects/seleniumwd2/basics/RunHeadlessChromeTests.py", line 15, in <module>
    wait.until(EC.element_to_be_clickable((By.LINK_TEXT, 'Login'))).click()
  File "C:\Users\vishr\AppData\Roaming\Python\Python37\site-packages\selenium\webdriver\support\wait.py", line 80, in until
    raise TimeoutException(message, screen, stacktrace)
selenium.common.exceptions.TimeoutException: Message: 


Process finished with exit code 1

Answer 1

对于无头浏览器，您必须设置窗口大小以触发事件。因为无头浏览器无法识别没有窗口大小的点击位置。

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

chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument('--headless')
chrome_options.add_argument('--disable-gpu')
chrome_options.add_argument('window-size=1920x1080')

driver = webdriver.Chrome(executable_path='path/to/chrome driver',options=chrome_options)
wait = WebDriverWait(driver,30)
driver.maximize_window()
driver.get('https://learn.letskodeit.com/')
print(driver.title)
wait.until(EC.element_to_be_clickable((By.LINK_TEXT, 'Login'))).click()
wait.until(EC.visibility_of_element_located((By.ID, 'user_email'))).send_keys("test@email.com")
wait.until(EC.visibility_of_element_located((By.ID, 'user_password'))).send_keys("abcabc")
wait.until(EC.visibility_of_element_located((By.NAME, 'commit'))).click()
print(driver.title)
driver.close()
driver.quit()

在无头模式下在控制台上打印输出。

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Answer 2

VISHVAMBRUTHJAVAGALTHIMMEGOWDA，

我尝试了您的代码并遇到了同样的异常，首先我认为 username 在 Frame 或 iframe 中，但事实并非如此。

然后我尝试引入 webdriver wait 并且效果很好：

代码：

wait = WebDriverWait(driver,10)

driver.maximize_window()

driver.get("https://learn.letskodeit.com/")

print(driver.title)

driver.find_element_by_xpath("//a[contains(text(),'Login')]").click()

wait.until(EC.visibility_of_element_located((By.ID, 'user_email'))).send_keys("test@email.com")

#driver.find_element_by_id("user_email").

driver.find_element_by_id("user_password").send_keys("abcabc")

driver.find_element_by_name("commit").click()

print(driver.title)  

记得导入这些：

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

编辑 1：

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import time

options = Options()
options.add_argument('--headless')
options.add_argument('--disable-gpu')  # Last I checked this was necessary.
driver = webdriver.Chrome("C:/Users/XXXX/Downloads/BrowserDriver/chromedriver_win32/chromedriver.exe", chrome_options=options)
wait = WebDriverWait(driver,10)

driver.get("https://learn.letskodeit.com/")

print(driver.title)


wait.until(EC.element_to_be_clickable((By.LINK_TEXT, 'Login'))).click()

wait.until(EC.visibility_of_element_located((By.ID, 'user_email'))).send_keys("test@email.com")

wait.until(EC.visibility_of_element_located((By.ID, 'user_password'))).send_keys("abcabc")

wait.until(EC.visibility_of_element_located((By.NAME, 'commit'))).click()

print(driver.title)

Answer 3

要在文本为 Login 的元素上 click()，您必须为 element_to_be_clickable() 诱导 WebDriverWait，您可以使用以下任一解决方案：

• 使用PARTIAL_LINK_TEXT：

  WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.PARTIAL_LINK_TEXT, "Login"))).click()
  

• 使用CSS_SELECTOR：

  WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.CSS_SELECTOR, "a.navbar-link.fedora-navbar-link[href='/sign_in']"))).click()
  

• 使用XPATH：

  WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.XPATH, "//a[@class='navbar-link fedora-navbar-link' and @href='/sign_in']"))).click()
  

• 注意：您必须添加以下导入：

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

Answer 4

您正在单击一个加载另一个页面的按钮。 您必须等待其他页面加载。这很难做到完美。

最简单的解决方案：

sleep(3)

使用隐式等待的更好解决方案：

driver.implicitly_wait(3)

使用显式等待的更好解决方案：

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, 3).until(EC.presence_of_element_located((By.ID, "user_email")))

更好的解决方案是捕获异常，并将所有这些解决方案分层。