Downloading with chrome headless and selenium

UPDATED PYTHON SOLUTION - TESTED Mar 4, 2021 on chromedriver v88 and v89

This will allow you to click to download files in headless mode.

    from selenium import webdriver
    from selenium.webdriver.common.keys import Keys
    from selenium.webdriver.chrome.options import Options

    # Instantiate headless driver
    chrome_options = Options()

    # Windows path
    chromedriver_location = 'C:\\path\\to\\chromedriver_win32\\chromedriver.exe'
    # Mac path. May have to allow chromedriver developer in os system prefs
    '/Users/path/to/chromedriver'

    chrome_options.add_argument("--headless")
    chrome_options.add_argument("--no-sandbox")
    chrome_options.add_argument("--disable-dev-shm-usage")
    
    chrome_prefs = {"download.default_directory": r"C:\path\to\Downloads"} # (windows)
    chrome_options.experimental_options["prefs"] = chrome_prefs

    driver = webdriver.Chrome(chromedriver_location,options=chrome_options)

    # Download your file
    driver.get('https://www.mockaroo.com/')
    driver.find_element_by_id('download').click()

This is a feature of Chrome to prevent from software to download files to your computer. There is a workaround though. Read more about it here.

What you need to do is enable it via DevTools, Something like that:

async function setDownload () {
  const client = await CDP({tab: 'ws://localhost:9222/devtools/browser'});
  const info =  await client.send('Browser.setDownloadBehavior', {behavior : "allow", downloadPath: "/tmp/"});
  await client.close();
}

This is the solution some one gave in the mentioned topic. Here is his comment.

Here's a working example for Python based on Shawn Button's answer. I've tested this with Chromium 68.0.3440.75 & chromedriver 2.38

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

chrome_options = Options()
chrome_options.add_experimental_option("prefs", {
  "download.default_directory": "/path/to/download/dir",
  "download.prompt_for_download": False,
})

chrome_options.add_argument("--headless")
driver = webdriver.Chrome(chrome_options=chrome_options)

driver.command_executor._commands["send_command"] = ("POST", '/session/$sessionId/chromium/send_command')
params = {'cmd': 'Page.setDownloadBehavior', 'params': {'behavior': 'allow', 'downloadPath': "/path/to/download/dir"}}
command_result = driver.execute("send_command", params)

driver.get('http://download-page.url/')
driver.find_element_by_css_selector("#download_link").click()

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.