Webshot
Captures a web page as a screenshot using Poltergeist, Capybara and PhantomJS.
Installation
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
Usage
# Setup Capybara
ws = Webshot::Screenshot.instance
# Capture Google's home page
ws.capture "http://www.google.com/", "google.png"
# Customize thumbnail
ws.capture "http://www.google.com/", "google.png", width: 100, height: 90, quality: 85
# Specify only width, height will be computed according to page's height
ws.capture "http://www.google.com/", "google.png", width: 1024
# Specify an array of additional HTTP status codes to accept,
# beyond normal success codes like 200 or 302
ws.capture "http://www.google.com/foo", "google_404.png", allowed_status_codes: [404]
# Customize thumbnail generation (MiniMagick)
# see: https://github.com/minimagick/minimagick
ws.capture("http://www.google.com/", "google.png") do |magick|
magick.combine_options do |c|
c.thumbnail "100x"
c.background "white"
c.extent "100x90"
c.gravity "north"
c.quality 85
end
endYou can wait some time after visit page before capturing screenshot.
# Timeout in seconds
ws.capture 'http://www.google.com/', 'google.png', timeout: 2You can login before capturing screenshot.
ws.start_session do
visit 'https://github.com/login'
fill_in 'Username or Email', :with => 'user@example.com'
fill_in 'Password', :with => 'password'
click_button 'Sign in'
end.capture 'https://github.com/username/', 'github.png'Scaling
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.
Notes:
- sed 's/S3/Your file hosting service/g'
- sed 's/CloudFront/Your CDN service/g'
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request