Handling modal dialogs in Selenium WebDriver with Python headless mode

[sofiap]

I’m working on a web scraping project using Selenium WebDriver with Python on an Ubuntu server. Since I’m running this in headless mode without a display, I keep running into modal dialog issues that prevent my script from continuing.

Here’s a simple example of what I’m trying to do:

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

# Setup headless browser
options = webdriver.ChromeOptions()
options.add_argument('--headless')
driver = webdriver.Chrome(options=options)

try:
    driver.get('https://example-site.com')
    # Wait for content to load
    wait = WebDriverWait(driver, 15)
    content = wait.until(EC.presence_of_element_located((By.ID, 'main-content')))
    print('Page loaded successfully')
except Exception as error:
    print(f'Error occurred: {error}')
finally:
    driver.quit()

The problem is I get a ‘Modal dialog present’ error that stops everything. What’s the best way to detect and dismiss these popup dialogs automatically in headless mode? Are there any specific methods or configurations I should use?

[Finn_Mystery]

Dealing with modal dialogs in headless mode can indeed be quite a hassle. From my experience, utilizing driver.switch_to.alert is fundamental for catching and dismissing alerts. You might also want to implement error handling with NoAlertPresentException to avoid breaking your flow when an alert isn’t present. I find that running a periodic check for alerts during page interactions until the required elements are fully loaded helps mitigate interruptions. Additionally, consider including --disable-web-security and --disable-extensions in your Chrome options; these settings can prevent some popups from appearing altogether.

[Alex_Thunder]

wrap ur main code in a try-except block to catch selenium’s UnexpectedAlertPresentException. when it hits, just run driver.switch_to.alert.accept() and keep scraping. works great for me in headless chrome - just heads up that sometimes you’ll need to handle several alerts in a row.

[sofiag]

I’ve encountered similar issues with sites that frequently trigger modal dialogs. To effectively manage them, I recommend creating a dedicated function that checks for alerts prior to executing significant actions. You can appropriately wrap driver.switch_to.alert in a try-except structure around your main code. Additionally, incorporating options like --disable-popup-blocking and --no-sandbox in your Chrome configurations can significantly reduce the occurrence of modal alerts. Timing is critical; some websites invoke alerts following specific events, so adding slight delays like time.sleep(1) after page loads, but before any interactions, can provide a buffer for handling these modal triggers.