Downloading with chrome headless and selenium

Question

I'm using python-selenium and Chrome 59 and trying to automate a simple download sequence. When I launch the browser normally, the download works, but when I do so in headless mode, the download doesn't work.

# Headless implementation
from selenium import webdriver

chromeOptions = webdriver.ChromeOptions()
chromeOptions.add_argument("headless")

driver = webdriver.Chrome(chrome_options=chromeOptions)

driver.get('https://www.mockaroo.com/')
driver.find_element_by_id('download').click()
# ^^^ Download doesn't start

---

# Normal Mode
from selenium import webdriver

driver = webdriver.Chrome()

driver.get('https://www.mockaroo.com/')
driver.find_element_by_id('download').click()
# ^^^ Download works normally

---

I've even tried adding a default path:

prefs = {"download.default_directory" : "/Users/Chetan/Desktop/"}
chromeOptions.add_argument("headless")
chromeOptions.add_experimental_option("prefs",prefs)

Adding a default path works in the normal implementation, but the same problem persists in the headless version.

How do I get the download to start in headless mode?

Answer 1

Yes, it's a "feature", for security. As mentioned before here is the bug discussion: https://bugs.chromium.org/p/chromium/issues/detail?id=696481

Support was added in chrome version 62.0.3196.0 or above to enable downloading.

Here is a python implementation. I had to add the command to the chromedriver commands. I will try to submit a PR so it is included in the library in the future.

def enable_download_in_headless_chrome(self, driver, download_dir):
    # add missing support for chrome "send_command"  to selenium webdriver
    driver.command_executor._commands["send_command"] = ("POST", '/session/$sessionId/chromium/send_command')

    params = {'cmd': 'Page.setDownloadBehavior', 'params': {'behavior': 'allow', 'downloadPath': download_dir}}
    command_result = driver.execute("send_command", params)

For reference here is a little repo to demonstrate how to use this: https://github.com/shawnbutton/PythonHeadlessChrome

update 2020-05-01 There have been comments saying this is not working anymore. Given this patch is now over a year old it's quite possible they have changed the underlying library.