I have an idea to build a Ruby script for a safe-browsing Firefox for younger kids in my family. My idea was to pull the current URL from the browser every so often, use the Nokogiri gem to parse the page for keywords (that might be found on a pornography page, for example), and shut the browser down if a certain number of matches are found.
Are there any APIs to allow that kind of interaction with the browser, preferably in Ruby?