Captures a web page as a screenshot.
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Captures a web page as a screenshot using Poltergeist, Capybara and PhantomJS.

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Download and install PhantomJS version 2.X, add the directory containing the binary to your PATH.

Add the webshot gem to your Gemfile:

gem "webshot"

And then execute:

$ bundle

Or install it yourself as:

$ gem install webshot


# Setup Capybara
ws = Webshot::Screenshot.instance

# Capture Google's home page
ws.capture "", "google.png"

# Customize thumbnail
ws.capture "", "google.png", width: 100, height: 90, quality: 85

# Specify only width, height will be computed according to page's height
ws.capture "", "google.png", width: 1024

# Specify an array of additional HTTP status codes to accept,
# beyond normal success codes like 200 or 302
ws.capture "", "google_404.png", allowed_status_codes: [404]

# Customize thumbnail generation (MiniMagick)
# see:
ws.capture("", "google.png") do |magick|
  magick.combine_options do |c|
    c.thumbnail "100x"
    c.background "white"
    c.extent "100x90"
    c.gravity "north"
    c.quality 85

You can wait some time after visit page before capturing screenshot.

# Timeout in seconds
ws.capture '', 'google.png', timeout: 2

You can login before capturing screenshot.

ws.start_session do
  visit ''
  fill_in 'Username or Email', :with => ''
  fill_in 'Password', :with => 'password'
  click_button 'Sign in'
end.capture '', 'github.png'


It's not recommended to start multiple PhantomJS concurrently. You should serialize requests, treat the process as unreliable and monitor it with daemontools, god, monit, etc.

Recommended setup:

 [S3] <-- [CloudFront + 404 handler] <-- User Request
Worker <--> [Queue] <-- App

The application triggers screenshot requests which are queued and then processed by a background worker (Resque, Sidekiq, etc). The worker uploads the images to S3 which are served through CloudFront. The CDN should be configured to serve a default image (404 handler) with a low TTL to handle screenshot are not yet ready or couldn't be generated.


  • sed 's/S3/Your file hosting service/g'
  • sed 's/CloudFront/Your CDN service/g'


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request