A few days ago I’ve discovered that Thumbshots.org stopped to deliver web page screenshots for my DNS checking tool.
I don’t know when it happened, at some point back in time I’ve noticed that they are serving a placeholder image instead of screenshots. After a quick investigation I’ve found that they have a quota for the free usage tier now.
I’m missing the thumbnails, they make the reports to look more attractive with a better look and feel. I’ve checked for alternatives and I’ve found nothing to satisfy my needs. Considering today’s ridiculous prices of a VPS and bandwidth I decided that I would implement a simple service which will generate web page screenshots and store them on Amazon S3.
The first thing which came into my mind was PhantomJS, I could generate screenshots using PhantomJS. After analyzing Node.js gluing modules for PhantomJS I decided that I shouldn’t add another piece to manage in my stack. I settled to a Ruby solution, thanks to Capybara and Poltergeist it was trivial to implement:
require "capybara/dsl"
require "capybara/poltergeist"
class Screenshot
include Capybara::DSL
# Captures a screenshot of +url+ saving it to +path+.
def capture(url, path)
# Browser settings
page.driver.resize(1024, 768)
page.driver.headers = {
"User-Agent" => "Webshot 1.0",
}
# Open page
visit url
if page.driver.status_code == 200
# Save screenshot
page.driver.save_screenshot(path, :full => true)
# Resize image
# ...
else
# Handle error
end
end
end
# By default Capybara will try to boot a rack application
# automatically. You might want to switch off Capybara's
# rack server if you are running against a remote application
Capybara.run_server = false
Capybara.register_driver :poltergeist do |app|
Capybara::Poltergeist::Driver.new(app, {
# Raise JavaScript errors to Ruby
js_errors: false,
# Additional command line options for PhantomJS
phantomjs_options: ['--ignore-ssl-errors=yes'],
})
end
Capybara.current_driver = :poltergeist
screenshot = Screenshot.new
screenshot.capture "http://www.google.com/", "output.png"
After adding resizing capabilities with mini_magick,
I’ve packed the example as a Ruby gem (webshot):
$ gem install webshot
# Setup Capybara
Webshot.capybara_setup!
# Take a screenshot of Google's home page
# and save it to a image file using png format
webshot = Webshot::Screenshot.new
webshot.capture "http://www.google.com/", "google.png"