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I'm learning to use Selenium for basic things like taking a screenshot, scraping, and testing and would like to use it with headless Chrome, which is now stable as of Chrome 59.

I have been able to take a screenshot using the 'selenium-webdriver' gem and chromedriver, but not headless.

Here is the ruby script that I am running which hangs after starting to initialize the driver

require 'rubygems'
require 'selenium-webdriver'

Selenium::WebDriver.logger.level = :debug
p 'initializing driver'
driver = Selenium::WebDriver.for :chrome, switches: %w[--headless --disable-gpu --screenshot --hide-scrollbars]
p 'navigating to Google'
driver.navigate.to "http://google.com"  
driver.save_screenshot("./screen.png")
driver.quit

and the output from the logs:

:> ruby rubytest.rb
"initializing driver"
2017-06-07 15:55:43 DEBUG Selenium Executing Process 

["/Users/name/Documents/scrapings/python/env/bin/chromedriver", "--port=9515"]
2017-06-07 15:55:43 DEBUG Selenium polling for socket on ["127.0.0.1", 9515]
Starting ChromeDriver 2.29.461585 (0be2cd95f834e9ee7c46bcc7cf405b483f5ae83b) on port 9515
Only local connections are allowed.
2017-06-07 15:55:43 INFO Selenium -> POST session
2017-06-07 15:55:43 INFO Selenium    >>> http://127.0.0.1:9515/session | {"desiredCapabilities":{"browserName":"chrome","version":"","platform":"ANY","javascriptEnabled":true,"cssSelectorsEnabled":true,"takesScreenshot":false,"nativeEvents":false,"rotatable":false,"chromeOptions":{"args":["--headless","--disable-gpu","--screenshot","--hide-scrollbars"]}}}
2017-06-07 15:55:43 DEBUG Selenium      > {"Accept"=>"application/json", "Content-Type"=>"application/json; charset=utf-8", "Content-Length"=>"284"}
[RUBY BACKTRACE TO DRIVER INITIALIZATION]

I have tried using the JavaScript and Python drivers with similar code and nothing works. When I try this with Python, the error message is 

WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally
  (Driver info: chromedriver=2.29.461585 (0be2cd95f834e9ee7c46bcc7cf405b483f5ae83b),platform=Mac OS X 10.12.5 x86_64)
Andrew Patterson
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    Is this of use? https://medium.com/@CukeHub/headless-chrome-with-ruby-cucumber-selenium-abf6da437fd9 – max pleaner Jun 08 '17 at 00:37
  • Yes, it was of some use, thank you. Passing the `--headless` argument through desired_capabilities allowed me to navigate and select elements headlessly; however, this method still does not give a screenshot like normal 'non-headless' Chrome. – Andrew Patterson Jun 08 '17 at 02:11
  • I just found a nice little [link](https://sermoa.wordpress.com/2013/10/24/getting-chromedriver-to-work-with-ruby-selenium-webdriver-under-osx-mavericks/) that deals with the same/similar problem. – Saša Zejnilović Jun 08 '17 at 11:15
  • I'm having the same issue with Ruby. Browser launches in headless mode OK, but resulting screenshot is empty. This works fine for me in Python and JavaScript. – boldfacedesignuk Jun 08 '17 at 11:22

3 Answers3

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I found this blog post useful for setting up headless chrome with selenium in ruby

require "selenium-webdriver"

# configure the driver to run in headless mode
options = Selenium::WebDriver::Chrome::Options.new
options.add_argument('--headless')
driver = Selenium::WebDriver.for :chrome, options: options

driver.navigate.to "https://www.google.com"

# resize the window and take a screenshot
driver.manage.window.resize_to(800, 800)
driver.save_screenshot "screenshot.png"
acowpy
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2

Managed to work through this in the end via various docs, blog posts and gists.

caps = Selenium::WebDriver::Remote::Capabilities.chrome("desiredCapabilities" => {"takesScreenshot" => true}, "chromeOptions" => {"binary" => "/Applications/Google Chrome Canary.app/Contents/MacOS/Google Chrome Canary"})

driver = Selenium::WebDriver.for :chrome, desired_capabilities: caps, switches: %w[--headless --no-sandbox --disable-gpu --remote-debugin-port=9222 --screen-size=1200x800]

You need to use a very recent version of Chrome (I'm using Canary) and tell Selenium the path to the binary. You also need to set the desired capabilities for 'takesScreenshot' to true.

boldfacedesignuk
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  • Note for anyone running things inside a Docker container, you'll need to replace element.send_keys() with this util function: def send_keys(d, el, str) d.execute_script('arguments[0].setAttribute("value", arguments[1])', el, str) end Use it like so: send_keys(driver, searchElement, "WebDriver") – boldfacedesignuk Jun 08 '17 at 16:21
  • I'm on Chrome 59 which is the most recent version, andI'm still getting a blank screenshot. Also, is there a reason that you have desiredCapabilities nested twice? – Andrew Patterson Jun 08 '17 at 18:25
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    Good question, and in fact you're right we can clean this up like so: caps = Selenium::WebDriver::Remote::Capabilities.chrome("desiredCapabilities" => {"takesScreenshot" => true}, "chromeOptions" => {"binary" => "/Applications/Google Chrome Canary.app/Contents/MacOS/Google Chrome Canary", "args" => ["--headless", "--no-sandbox", "--disable-gpu", "--remote-debugin-port=9222", "--screen-size=1200x800"]}) driver = Selenium::WebDriver.for :chrome, desired_capabilities: caps – boldfacedesignuk Jun 09 '17 at 07:56
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    Not sure why screenshots don't work with v59, but you can download Canary (v61) here: https://www.google.com/chrome/browser/canary.html Hopefully whatever fixes are in v61 will filter into the stable release sooner rather than later. – boldfacedesignuk Jun 09 '17 at 08:04
2

I've written a blog post about how to do it. Summing up:

1) Make sure you have Chrome version 57+ on Linux, 59+ on macOS or 60+ on Windows;

2) Add/update the gem selenium-webdriver;

3) Make sure you’re using ChromeDriver version 2.30 or higher;

4) Add the following driver to your spec_helper.rb or rails_helper.rb:

Capybara.register_driver :chrome do |app|
  Capybara::Selenium::Driver.new app, browser: :chrome,
    options: Selenium::WebDriver::Chrome::Options.new(args: %w[headless disable-gpu])
end

Capybara.javascript_driver = :chrome
Lucas Caton
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