I would like to generate HTML Snapshots using Watir, hosted on Heroku.
Google's Full Specification for Making AJAX Applications Crawlable suggests using HTMLUnit... see How do I create an HTML snapshot? point #3.
HtmlUnit is a Java-only headless browser emulator; and unfortunately jRuby is not an option on Heroku. So HtmlUnit is ruled out (to my knowledge).
If you're interested I have another question open regarding HtmlUnit as a service hosted on Google App Engine... Making AJAX Applications Crawlable? How to build a simple web service on Google App Engine to produce HTML Snapshots? ... still waiting on a proven example/answer.
No. You need a full desktop environment to run watir. Heroku doesn't provide you with that.
You could use a service such as Amazon EC2
Yes you can
Use Watir with PhantomJS, which is headless
browser = Watir::Browser.new :phantomjs
To use PhantomJS on Heroku, you'll need to use a Heroku PhantomJS buildpack
Troelskin's answer is incorrect. There are ways to run "headless" browsers with Watir, which do not require a "full desktop environment". Having said that, I do not know which method may be appropriate on Heroku.
Other "headless" automation options (if you are using Ruby) are Mechanize with Open-Uri, along with (optional) Nokogiri.
来源：https://stackoverflow.com/questions/3597118/can-you-deploy-watir-on-heroku-to-generate-html-snapshots-if-so-how