I have a WebDriver testsuite, which operates different when I execute it in normal and headless browser. There is an element which is not found when I execute it in headless mode, but found when I use the same code, same driver in normal mode. I use this flag to set headless mode:
chromeOptions.addArguments("--headless"); There is ChromeDriver 2.31 and WebDriver 3.5.2 in use. How could I debug this?
There are two ways to debug. You can get Page Source and check what is different.
Now when you launch a browser using Selenium, it is using the Debugging session to automate chrome. So you can't do a remote debugger to your website using this.
You need to launch chrome manually.
chrome --headless --remote-debugging-port=9222 --disable-gpu http://tarunlalwani.com Now in open another chrome and debug the site by going to http://127.0.0.1:9222 and inspect the site.
for debugging headless, try to get an screenshot before the error:
in Python:
WINDOW_SIZE = "1200,900" opts.add_argument("--window-size=%s" % self.WINDOW_SIZE) if self.HEADLESS: opts.add_argument('--headless') self.driver = webdriver.Chrome(executable_path=chromedriver,options=opts) driver.save_screenshot('./foto.png') for anyone struggling with this (as i was), there's a powerful method you can use in selenium called execute_script.
as an example, i was finding an element by xpath and clicking on it:
browser.find_element_by_xpath("//li[@id='tabletid']").click() but this wasn't working in headless. after inspecting the element i found out the button click actually executes a simple javascript line. so i replaced this line with:
js = """drawTable(); return false;""" browser.execute_script(js) and i was able to actually pull my data! now my script will work in ssh, docker, etc.
<div id="answer-64273543" class="answer" data-answerid="answer-64273543"... if i parse thru it and find the button to "add comment" as <button type="submit" class="s-btn s-btn_primary">... i could select that element and .click() it in selenium. or if there were an equivalent javascript code that got ran when i clicked add comment i.e. addComment(); return false; i could use .execute_script() to run that instead, in case there are multiple elements or the driver can't find it