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Ferrum - high-level API to control Chrome in Ruby

<img align="right" width="320" height="241" alt="Ferrum logo" src="https://raw.githubusercontent.com/rubycdp/ferrum/main/logo.svg?sanitize=true">

As simple as Puppeteer, though even simpler.

It is Ruby clean and high-level API to Chrome. Runs headless by default, but you can configure it to run in a headful mode. All you need is Ruby and Chrome or Chromium. Ferrum connects to the browser by CDP protocol and there's no Selenium/WebDriver/ChromeDriver dependency. The emphasis was made on a raw CDP protocol because Chrome allows you to do so many things that are barely supported by WebDriver because it should have consistent design with other browsers.

The development is done in RubyMine provided by OSS license.

Index

Install

There's no official Chrome or Chromium package for Linux don't install it this way because it's either outdated or unofficial, both are bad.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

Add this to your Gemfile and run bundle install.

gem "ferrum"

Examples

Navigate to a website and save a screenshot:

browser = Ferrum::Browser.new
browser.go_to("https://google.com")
browser.screenshot(path: "google.png")
browser.quit

When you work with browser instance Ferrum creates and maintains a default page for you, in fact all the methods above are sent to the page instance that is created in the default_context of the browser instance. You can interact with a page created manually and this is preferred:

browser = Ferrum::Browser.new
page = browser.create_page
page.go_to("https://google.com")
input = page.at_xpath("//input[@name='q']")
input.focus.type("Ruby headless driver for Chrome", :Enter)
page.at_css("a > h3").text # => "rubycdp/ferrum: Ruby Chrome/Chromium driver - GitHub"
browser.quit

Evaluate some JavaScript and get full width/height:

browser = Ferrum::Browser.new
page = browser.create_page
page.go_to("https://www.google.com/search?q=Ruby+headless+driver+for+Capybara")
width, height = page.evaluate <<~JS
  [document.documentElement.offsetWidth,
   document.documentElement.offsetHeight]
JS
# => [1024, 1931]
browser.quit

Do any mouse movements you like:

# Trace a 100x100 square
browser = Ferrum::Browser.new
page = browser.create_page
page.go_to("https://google.com")
page.mouse
  .move(x: 0, y: 0)
  .down
  .move(x: 0, y: 100)
  .move(x: 100, y: 100)
  .move(x: 100, y: 0)
  .move(x: 0, y: 0)
  .up

browser.quit

Docker

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

Ferrum::Browser.new(browser_options: { 'no-sandbox': nil })

It has also been reported that the Chrome process repeatedly crashes when running inside a Docker container on an M1 Mac preventing Ferrum from working. Ferrum should work as expected when deployed to a Docker container on a non-M1 Mac.

Customization

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

Ferrum::Browser.new(options)

Navigation

go_to(url) : String

Navigate page to.

page.go_to("https://github.com/")

back

Navigate to the previous page in history.

page.go_to("https://github.com/")
page.at_xpath("//a").click
page.back

forward

Navigate to the next page in history.

page.go_to("https://github.com/")
page.at_xpath("//a").click
page.back
page.forward

refresh

Reload current page.

page.go_to("https://github.com/")
page.refresh

stop

Stop all navigations and loading pending resources on the page

page.go_to("https://github.com/")
page.stop

position = **options

Set the position for the browser window

browser.position = { left: 10, top: 20 }

position : Array<Integer>

Get the position for the browser window

browser.position # => [10, 20]

window_bounds = **options

Set window bounds

browser.window_bounds = { left: 10, top: 20, width: 1024, height: 768, window_state: "normal" }

window_bounds : Hash<String, Integer | String>

Get window bounds

browser.window_bounds # => { "left": 0, "top": 1286, "width": 10, "height": 10, "windowState": "normal" }

window_id : Integer

Current window id

browser.window_id # => 1

Finders

at_css(selector, **options) : Node | nil

Find node by selector. Runs document.querySelector within the document or provided node.

page.go_to("https://github.com/")
page.at_css("a[aria-label='Issues you created']") # => Node

css(selector, **options) : Array<Node> | []

Find nodes by selector. The method runs document.querySelectorAll within the document or provided node.

page.go_to("https://github.com/")
page.css("a[aria-label='Issues you created']") # => [Node]

at_xpath(selector, **options) : Node | nil

Find node by xpath.

page.go_to("https://github.com/")
page.at_xpath("//a[@aria-label='Issues you created']") # => Node

xpath(selector, **options) : Array<Node> | []

Find nodes by xpath.

page.go_to("https://github.com/")
page.xpath("//a[@aria-label='Issues you created']") # => [Node]

current_url : String

Returns current top window location href.

page.go_to("https://google.com/")
page.current_url # => "https://www.google.com/"

current_title : String

Returns current top window title

page.go_to("https://google.com/")
page.current_title # => "Google"

body : String

Returns current page's html.

page.go_to("https://google.com/")
page.body # => '<html itemscope="" itemtype="http://schema.org/WebPage" lang="ru"><head>...

Screenshots

screenshot(**options) : String | Integer

Saves screenshot on a disk or returns it as base64.

page.go_to("https://google.com/")
# Save on the disk in PNG
page.screenshot(path: "google.png") # => 134660
# Save on the disk in JPG
page.screenshot(path: "google.jpg") # => 30902
# Save to Base64 the whole page not only viewport and reduce quality
page.screenshot(full: true, quality: 60, encoding: :base64) # "iVBORw0KGgoAAAANSUhEUgAABAAAAAMACAYAAAC6uhUNAAAAAXNSR0IArs4c6Q...
# Save on the disk with the selected element in PNG
page.screenshot(path: "google.png", selector: 'textarea') # => 11340
# Save to Base64 with an area of the page in PNG
page.screenshot(path: "google.png", area: { x: 0, y: 0, width: 400, height: 300 }) # => 54239
# Save with specific background color
page.screenshot(background_color: Ferrum::RGBA.new(0, 0, 0, 0.0))

pdf(**options) : String | Boolean

Saves PDF on a disk or returns it as base64.

page.go_to("https://google.com/")
# Save to disk as a PDF
page.pdf(path: "google.pdf", paper_width: 1.0, paper_height: 1.0) # => true

mhtml(**options) : String | Integer

Saves MHTML on a disk or returns it as a string.

page.go_to("https://google.com/")
page.mhtml(path: "google.mhtml") # => 87742

Network

page.network

traffic Array<Network::Exchange>

Returns all information about network traffic as Network::Exchange instance which in general is a wrapper around request, response and error.

page.go_to("https://github.com/")
page.network.traffic # => [#<Ferrum::Network::Exchange, ...]

request : Network::Request

Page request of the main frame.

page.go_to("https://github.com/")
page.network.request # => #<Ferrum::Network::Request...

response : Network::Response

Page response of the main frame.

page.go_to("https://github.com/")
page.network.response # => #<Ferrum::Network::Response...

status : Integer

Contains the status code of the main page response (e.g., 200 for a success). This is just a shortcut for response.status.

page.go_to("https://github.com/")
page.network.status # => 200

wait_for_idle(**options) : Boolean

Waits for network idle, returns true in case of success and false if there are still connections.

page.go_to("https://example.com/")
page.at_xpath("//a[text() = 'No UI changes button']").click
page.network.wait_for_idle # => true

wait_for_idle!(**options)

Waits for network idle or raises Ferrum::TimeoutError error. Accepts same arguments as wait_for_idle.

page.go_to("https://example.com/")
page.at_xpath("//a[text() = 'No UI changes button']").click
page.network.wait_for_idle! # might raise an error

clear(type)

Clear page's cache or collected traffic.

traffic = page.network.traffic # => []
page.go_to("https://github.com/")
traffic.size # => 51
page.network.clear(:traffic)
traffic.size # => 0

intercept(**options)

Set request interception for given options. This method is only sets request interception, you should use on callback to catch requests and abort or continue them.

browser = Ferrum::Browser.new
page = browser.create_page
page.network.intercept
page.on(:request) do |request|
  if request.match?(/bla-bla/)
    request.abort
  elsif request.match?(/lorem/)
    request.respond(body: "Lorem ipsum")
  else
    request.continue
  end
end
page.go_to("https://google.com")

authorize(**options, &block)

If site or proxy uses authorization you can provide credentials using this method.

page.network.authorize(user: "login", password: "pass") { |req| req.continue }
page.go_to("http://example.com/authenticated")
puts page.network.status # => 200
puts page.body # => Welcome, authenticated client

Since Chrome implements authorize using request interception you must continue or abort authorized requests. If you already have code that uses interception you can use authorize without block, but if not you are obliged to pass block, so this is version doesn't pass block and can work just fine:

browser = Ferrum::Browser.new
page = browser.create_page
page.network.intercept
page.on(:request) do |request|
  if request.resource_type == "Image"
    request.abort
  else
    request.continue
  end
end

page.network.authorize(user: "login", password: "pass", type: :proxy)

page.go_to("https://google.com")

You used to call authorize method without block, but since it's implemented using request interception there could be a collision with another part of your code that also uses request interception, so that authorize allows the request while your code denies but it's too late. The block is mandatory now.

emulate_network_conditions(**options)

Activates emulation of network conditions.

page.network.emulate_network_conditions(connection_type: "cellular2g")
page.go_to("https://github.com/")

offline_mode

Activates offline mode for a page.

page.network.offline_mode
page.go_to("https://github.com/") # => Ferrum::StatusError (Request to https://github.com/ failed(net::ERR_INTERNET_DISCONNECTED))

cache(disable: Boolean)

Toggles ignoring cache for each request. If true, cache will not be used.

page.network.cache(disable: true)

Downloads

page.downloads

files Array<Hash>

Returns all information about downloaded files as a Hash.

page.go_to("http://localhost/attachment.pdf")
page.downloads.files # => [{"frameId"=>"E3316DF1B5383D38F8ADF7485005FDE3", "guid"=>"11a68745-98ac-4d54-9b57-9f9016c268b3", "url"=>"http://localhost/attachment.pdf", "suggestedFilename"=>"attachment.pdf", "totalBytes"=>4911, "receivedBytes"=>4911, "state"=>"completed"}]

wait(timeout)

Waits until the download is finished.

page.go_to("http://localhost/attachment.pdf")
page.downloads.wait

or

page.go_to("http://localhost/page")
page.downloads.wait { page.at_css("#download").click }

set_behavior(**options)

Sets behavior in case of file to be downloaded.

page.go_to("https://example.com/")
page.downloads.set_behavior(save_path: "/tmp", behavior: :allow)

Proxy

You can set a proxy with a :proxy option:

Ferrum::Browser.new(proxy: { host: "x.x.x.x", port: "8800", user: "user", password: "pa$$" })

:bypass can specify semi-colon-separated list of hosts for which proxy shouldn't be used:

Ferrum::Browser.new(proxy: { host: "x.x.x.x", port: "8800", bypass: "*.google.com;*foo.com" })

In general passing a proxy option when instantiating a browser results in a browser running with proxy command line flags, so that it affects all pages and contexts. You can create a page in a new context which can use its own proxy settings:

browser = Ferrum::Browser.new

browser.create_page(proxy: { host: "x.x.x.x", port: 31337, user: "user", password: "password" }) do |page|
  page.go_to("https://api.ipify.org?format=json")
  page.body # => "x.x.x.x"
end

browser.create_page(proxy: { host: "y.y.y.y", port: 31337, user: "user", password: "password" }) do |page|
  page.go_to("https://api.ipify.org?format=json")
  page.body # => "y.y.y.y"
end

Mouse

page.mouse

scroll_to(x, y)

Scroll page to a given x, y

page.go_to("https://www.google.com/search?q=Ruby+headless+driver+for+Capybara")
page.mouse.scroll_to(0, 400)

click(**options) : Mouse

Click given coordinates, fires mouse move, down and up events.

down(**options) : Mouse

Mouse down for given coordinates.

up(**options) : Mouse

Mouse up for given coordinates.

move(x:, y:, steps: 1) : Mouse

Mouse move to given x and y.

Keyboard

page.keyboard

down(key) : Keyboard

Dispatches a keydown event.

up(key) : Keyboard

Dispatches a keyup event.

type(*keys) : Keyboard

Sends a keydown, keypress/input, and keyup event for each character in the text.

modifiers(keys) : Integer

Returns bitfield for a given keys

Cookies

page.cookies

all : Hash<String, Cookie>

Returns cookies hash

page.cookies.all # => {"NID"=>#<Ferrum::Cookies::Cookie:0x0000558624b37a40 @attributes={"name"=>"NID", "value"=>"...", "domain"=>".google.com", "path"=>"/", "expires"=>1583211046.575681, "size"=>178, "httpOnly"=>true, "secure"=>false, "session"=>false}>}

: Cookie

Returns cookie

page.cookies["NID"] # => <Ferrum::Cookies::Cookie:0x0000558624b67a88 @attributes={"name"=>"NID", "value"=>"...", "domain"=>".google.com", "path"=>"/", "expires"=>1583211046.575681, "size"=>178, "httpOnly"=>true, "secure"=>false, "session"=>false}>

set(value) : Boolean

Sets a cookie

page.cookies.set(name: "stealth", value: "omg", domain: "google.com") # => true

nid_cookie = page.cookies["NID"] # => <Ferrum::Cookies::Cookie:0x0000558624b67a88>
page.cookies.set(nid_cookie) # => true

remove(**options) : Boolean

Removes given cookie

page.cookies.remove(name: "stealth", domain: "google.com") # => true

clear : Boolean

Removes all cookies for current page

page.cookies.clear # => true

store(path) : Boolean

Stores all cookies of current page in a file.

# Cookies are saved into cookies.yml
page.cookies.store # => 15657

load(path) : Boolean

Loads all cookies from the file and sets them for current page.

# Cookies are loaded from cookies.yml
page.cookies.load # => true

Headers

page.headers

get : Hash

Get all headers

set(headers) : Boolean

Set given headers. Eventually clear all headers and set given ones.

add(headers) : Boolean

Adds given headers to already set ones.

clear : Boolean

Clear all headers.

JavaScript

evaluate(expression, *args)

Evaluate and return result for given JS expression

page.evaluate("[window.scrollX, window.scrollY]")

evaluate_async(expression, wait_time, *args)

Evaluate asynchronous expression and return result

page.evaluate_async(%(arguments[0]({foo: "bar"})), 5) # => { "foo" => "bar" }

execute(expression, *args)

Execute expression. Doesn't return the result

page.execute(%(1 + 1)) # => true

evaluate_on_new_document(expression)

Evaluate JavaScript to modify things before a page load

browser.evaluate_on_new_document <<~JS
  Object.defineProperty(navigator, "languages", {
    get: function() { return ["tlh"]; }
  });
JS

add_script_tag(**options) : Boolean

page.add_script_tag(url: "http://example.com/stylesheet.css") # => true

add_style_tag(**options) : Boolean

page.add_style_tag(content: "h1 { font-size: 40px; }") # => true

bypass_csp(**options) : Boolean

page.bypass_csp # => true
page.go_to("https://github.com/ruby-concurrency/concurrent-ruby/blob/master/docs-source/promises.in.md")
page.refresh
page.add_script_tag(content: "window.__injected = 42")
page.evaluate("window.__injected") # => 42

Emulation

disable_javascript

Disables Javascripts from the loaded HTML source. You can still evaluate JavaScript with evaluate or execute. Returns nothing.

page.disable_javascript

set_viewport

Overrides device screen dimensions and emulates viewport.

page.set_viewport(width: 1000, height: 600, scale_factor: 3)

Frames

frames : Array[Frame] | []

Returns all the frames current page have.

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
page.frames # =>
# [
#   #<Ferrum::Frame @id="C6D104CE454A025FBCF22B98DE612B12" @parent_id=nil @name=nil @state=:stopped_loading @execution_id=1>,
#   #<Ferrum::Frame @id="C09C4E4404314AAEAE85928EAC109A93" @parent_id="C6D104CE454A025FBCF22B98DE612B12" @state=:stopped_loading @execution_id=2>,
#   #<Ferrum::Frame @id="2E9C7F476ED09D87A42F2FEE3C6FBC3C" @parent_id="C6D104CE454A025FBCF22B98DE612B12" @state=:stopped_loading @execution_id=3>,
#   ...
# ]

main_frame : Frame

Returns page's main frame, the top of the tree and the parent of all frames.

frame_by(**options) : Frame | nil

Find frame by given options.

page.frame_by(id: "C6D104CE454A025FBCF22B98DE612B12")

Frame

id : String

Frame's unique id.

parent_id : String | nil

Parent frame id if this one is nested in another one.

execution_id : Integer

Execution context id which is used by JS, each frame has it's own context in which JS evaluates.

name : String | nil

If frame was given a name it should be here.

state : Symbol | nil

One of the states frame's in:

url : String

Returns current frame's location href.

page.go_to("https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe")
frame = page.frames[1]
frame.url # => https://interactive-examples.mdn.mozilla.net/pages/tabbed/iframe.html

title

Returns current frame's title.

page.go_to("https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe")
frame = page.frames[1]
frame.title # => HTML Demo: <iframe>

main? : Boolean

If current frame is the main frame of the page (top of the tree).

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
frame = page.frame_by(id: "C09C4E4404314AAEAE85928EAC109A93")
frame.main? # => false

current_url : String

Returns current frame's top window location href.

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
frame = page.frame_by(id: "C09C4E4404314AAEAE85928EAC109A93")
frame.current_url # => "https://www.w3schools.com/tags/tag_frame.asp"

current_title : String

Returns current frame's top window title.

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
frame = page.frame_by(id: "C09C4E4404314AAEAE85928EAC109A93")
frame.current_title # => "HTML frame tag"

body : String

Returns current frame's html.

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
frame = page.frame_by(id: "C09C4E4404314AAEAE85928EAC109A93")
frame.body # => "<html><head></head><body></body></html>"

doctype

Returns current frame's doctype.

page.go_to("https://www.w3schools.com/tags/tag_frame.asp")
page.main_frame.doctype # => "<!DOCTYPE html>"

content = html

Sets a content of a given frame.

page.go_to("https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe")
frame = page.frames[1]
frame.body # <html lang="en"><head><style>body {transition: opacity ease-in 0.2s; }...
frame.content = "<html><head></head><body><p>lol</p></body></html>"
frame.body # => <html><head></head><body><p>lol</p></body></html>

Dialogs

accept(text)

Accept dialog with given text or default prompt if applicable

dismiss

Dismiss dialog

page.on(:dialog) do |dialog|
  if dialog.match?(/bla-bla/)
    dialog.accept
  else
    dialog.dismiss
  end
end
page.go_to("https://google.com")

Animation

You can slow down or speed up CSS animations.

playback_rate : Integer

Returns playback rate for CSS animations, defaults to 1.

playback_rate = value

Sets playback rate of CSS animations

page.playback_rate = 2000
page.go_to("https://google.com")
page.playback_rate # => 2000

Node

node? : Boolean

frame_id

frame : Frame

Returns Frame object for current node, you can keep using Finders for that object:

frame =  page.at_xpath("//iframe").frame # => Frame
frame.at_css("//a[text() = 'Log in']") # => Node

focus

focusable?

moving? : Boolean

wait_for_stop_moving

blur

type

click

hover

select_file

at_xpath

at_css

xpath

css

text

inner_text

value

property

attribute

evaluate

selected : Array<Node>

select

scroll_into_view

in_viewport?(of: Node | nil) : Boolean

remove

exists?

(chainable) Selects options by passed attribute.

page.at_xpath("//*[select]").select(["1"]) # => Node (select)
page.at_xpath("//*[select]").select(["text"], by: :text) # => Node (select)

Accept string, array or strings:

page.at_xpath("//*[select]").select("1")
page.at_xpath("//*[select]").select("1", "2")
page.at_xpath("//*[select]").select(["1", "2"])

Tracing

You can use tracing.record to create a trace file which can be opened in Chrome DevTools or timeline viewer.

page.tracing.record(path: "trace.json") do
  page.go_to("https://www.google.com")
end

tracing.record(**options) : String

Accepts block, records trace and by default returns trace data from Tracing.tracingComplete event as output. When path is specified returns true and stores trace data into file.

Clean Up

reset

Closes browser tabs opened by the Browser instance.

# connect to a long-running Chrome process
browser = Ferrum::Browser.new(url: 'http://localhost:9222')

browser.go_to("https://github.com/")

# clean up, lest the tab stays there hanging forever
browser.reset

browser.quit

Thread safety

Ferrum is fully thread-safe. You can create one browser or a few as you wish and start playing around using threads. Example below shows how to create a few pages which share the same context. Context is similar to an incognito profile but you can have more than one, think of it like it's independent browser session:

browser = Ferrum::Browser.new
context = browser.contexts.create

t1 = Thread.new(context) do |c|
  page = c.create_page
  page.go_to("https://www.google.com/search?q=Ruby+headless+driver+for+Capybara")
  page.screenshot(path: "t1.png")
end

t2 = Thread.new(context) do |c|
  page = c.create_page
  page.go_to("https://www.google.com/search?q=Ruby+static+typing")
  page.screenshot(path: "t2.png")
end

t1.join
t2.join

context.dispose
browser.quit

or you can create two independent contexts:

browser = Ferrum::Browser.new

t1 = Thread.new(browser) do |b|
  context = b.contexts.create
  page = context.create_page
  page.go_to("https://www.google.com/search?q=Ruby+headless+driver+for+Capybara")
  page.screenshot(path: "t1.png")
  context.dispose
end

t2 = Thread.new(browser) do |b|
  context = b.contexts.create
  page = context.create_page
  page.go_to("https://www.google.com/search?q=Ruby+static+typing")
  page.screenshot(path: "t2.png")
  context.dispose
end

t1.join
t2.join

browser.quit

Development

After checking out the repo, run bundle install to install dependencies.

Then, run bundle exec rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub.

License

The gem is available as open source under the terms of the MIT License.