Cuprite - Headless Chrome driver for Capybara

Cuprite is a pure Ruby driver (read as no Java/Selenium/WebDriver/ChromeDriver requirement) for Capybara. It allows you to run your Capybara tests on a headless Chrome or Chromium by CDP protocol. Under the hood it uses Ferrum which is high-level API to the browser again by CDP protocol.

The emphasis was made on raw CDP protocol because Headless Chrome allows you to do so many things that are barely supported by WebDriver because it should have consistent design with other browsers. The design of the driver will be as close to Poltergeist as possible though it's not a goal.

Install

Add these lines to your Gemfile and run bundle install.

gem "cuprite", group: :test

In your test setup add:

require "capybara/cuprite"
Capybara.javascript_driver = :cuprite
Capybara.register_driver(:cuprite) do |app|
  Capybara::Cuprite::Driver.new(app, window_size: [1200, 800])
end

If you already had tests on Poltergeist then it should simply work, for Selenium you better check your code for .manage calls because things are much easier with Cuprite, see the documentation below.

Install Chrome

There's no official Chrome or Chromium package for Linux don't install it this way because it either will be outdated or unofficial, both are bad. Download it from official source. Chrome binary should be in the PATH or BROWSER_PATH or you can pass it as an option

Customization

You can customize options with the following code in your test setup:

Capybara.register_driver(:cuprite) do |app|
  Capybara::Cuprite::Driver.new(app, options)
end

Running in Docker

In docker as root you must pass the no-sandbox browser option:

Capybara::Cuprite::Driver.new(app, browser_options: { 'no-sandbox': nil })

options Hash
- :browser_path (String) - Path to chrome binary, you can also set ENV variable as BROWSER_PATH=some/path/chrome bundle exec rspec.
- :headless (Boolean) - Set browser as headless or not, true by default.
- :slowmo (Integer | Float) - Set a delay to wait before sending command. Usefull companion of headless option, so that you have time to see changes.
- :logger (Object responding to puts) - When present, debug output is written to this object.
- :timeout (Numeric) - The number of seconds we'll wait for a response when communicating with browser. Default is 5.
- :js_errors (Boolean) - When true, JavaScript errors get re-raised in Ruby.
- :window_size (Array) - The dimensions of the browser window in which to test, expressed as a 2-element array, e.g. [1024, 768]. Default: [1024, 768]
- :browser_options (Hash) - Additional command line options, see them all e.g. { "ignore-certificate-errors" => nil }
- :extensions (Array) - An array of JS files to be preloaded into the browser
- :port (Integer) - Remote debugging port for headless Chrome
- :host (String) - Remote debugging address for headless Chrome
- :url (String) - URL for a running instance of Chrome. If this is set, a browser process will not be spawned.
- :url_blacklist (Array) - array of strings to match against requested URLs
- :url_whitelist (Array) - array of strings to match against requested URLs
- :process_timeout (Integer) - How long to wait for the Chrome process to respond on startup

Clicking/Scrolling

page.driver.click(x, y) Click a very specific area of the screen.
page.driver.scroll_to(left, top) Scroll to given position.
element.send_keys(*keys) Send keys to given node.

Request headers

Manipulate HTTP request headers like a boss:

page.driver.headers # => {}
page.driver.headers = { "User-Agent" => "Cuprite" }
page.driver.add_headers("Referer" => "https://example.com")
page.driver.headers # => { "User-Agent" => "Cuprite", "Referer" => "https://example.com" }

Notice that headers= will overwrite already set headers. You should use add_headers if you want to add a few more. These headers will apply to all subsequent HTTP requests (including requests for assets, AJAX, etc). They will be automatically cleared at the end of the test.

Network traffic

page.driver.network_traffic Inspect network traffic (resources have been loaded) on the current page. This returns an array of request objects.

page.driver.network_traffic # => [Request, ...]
request = page.driver.network_traffic.first
request.response

Please note that network traffic is not cleared when you visit new page. You can manually clear the network traffic by calling page.driver.clear_network_traffic or page.driver.reset

Manipulating cookies

The following methods are used to inspect and manipulate cookies:

page.driver.cookies - a hash of cookies accessible to the current page. The keys are cookie names. The values are Cookie objects, with the following methods: name, value, domain, path, size, secure?, httponly?, session?, expires.
page.driver.set_cookie(name, value, options = {}) - set a cookie. The options hash can take the following keys: :domain, :path, :secure, :httponly, :expires. :expires should be a Time object.
page.driver.remove_cookie(name) - remove a cookie
page.driver.clear_cookies - clear all cookies

Screenshot

Besides capybara screenshot method you can get image as Base64:

page.driver.render_base64(format, options)

Authorization

page.driver.basic_authorize(user, password)
page.driver.set_proxy(ip, port, type, user, password)

URL Blacklisting & Whitelisting

Cuprite supports URL blacklisting, which allows you to prevent scripts from running on designated domains:

page.driver.browser.url_blacklist = ["http://www.example.com"]

and also URL whitelisting, which allows scripts to only run on designated domains:

page.driver.browser.url_whitelist = ["http://www.example.com"]

If you are experiencing slower run times, consider creating a URL whitelist of domains that are essential or a blacklist of domains that are not essential, such as ad networks or analytics, to your testing environment.

Remote debugging

If you use the inspector: true option, remote debugging will be enabled. When this option is enabled, you can insert page.driver.debug into your tests to pause the test and launch a browser which gives you the Chrome inspector to view all your open pages and inspect them.

You can register this debugger driver with a different name and set it as the current javascript driver. By example, in your helper file:

Capybara.register_driver :cuprite_debug do |app|
  Capybara::Cuprite::Driver.new(app, inspector: true)
end

Capybara.javascript_driver = :cuprite_debug

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

krisleech/cuprite