What is the difference in accessing Cloudflare website using ChromeDriver/Chrome in normal/headless mode through Selenium Python

Question

I have a question about --headless mode in Python Selenium for Chrome.

Code

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

 CHROME_DRIVER_DIR = "selenium/chromedriver"

 chrome_options = webdriver.ChromeOptions()
 caps = DesiredCapabilities().CHROME
 chrome_options.add_argument("--disable-dev-shm-usage")
 chrome_options.add_argument("--remote-debugging-port=9222")
 chrome_options.add_argument("--headless")  # Runs Chrome in headless mode.
 chrome_options.add_argument('--no-sandbox')  # # Bypass OS security model
 chrome_options.add_argument("--disable-extensions")
 chrome_options.add_argument("--disable-gpu")

 browser = webdriver.Chrome(desired_capabilities=caps, executable_path=CHROME_DRIVER_DIR, options=chrome_options)

 browser.get("https://www.manta.com/c/mm2956g/mashuda-contractors")
 print(browser.page_source)
 browser.quit()

When I'm remove chrome_options.add_argument("--headless") all working good, but with this --headless* got next issue

Please enable cookies.

Error 1020 Ray ID: 53fd62b4087d8116 • 2019-12-04 11:19:28 UTC

Access denied

What happened?
This website is using a security service to protect itself from online attacks.

Cloudflare Ray ID: 53fd62b4087d8116 • Your IP: 168.81.117.111 • Performance & security by Cloudflare

What is the difference for normal mode and --headless?

Answer 1

When scraping CloudFlare protected website, here is the list of things you need to do:

1. Ensure you are sending headers identical (and in the same order) to what browser sends
2. Ensure you are using non-datacenter ip address range
3. And if it still does not work, like in my case...

I encountered the same issue when scraping one ecommerce website (guess dot com). Changing headers order didn't fix it for me. My conclusions: apparently, CloudFlare analyses the TLS fingerprint of the request and throws 403 (1020) code in case the fingerprint matches node.js/python/curl which are usually used for scraping. The solution is to emulate the fingeprint of some popular browser - and the most obvious way would be to use Puppeteer.js with puppeteer extra stealth plugin. And it worked! But.. since Puppeteer was not fast enough for my use case (I put it mildly.. Puppeteer is insane in terms of resources and sluggishness) I had to build an utility which uses boringSSL (the SSL lib used by Chrome) - and since compiling C/C++ code and figuring out the cryptic compilation errors of some TLS library is no fun for most of web devs - I wrapped it as an API server, which you can try here: https://rapidapi.com/restyler/api/scrapeninja

Read more on how CloudFlare analyzes TLS: https://blog.cloudflare.com/monsters-in-the-middleboxes/