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An unholy amalgam of therubyracer's V8 engine and emscripted-ruby to allow a truly sandboxed Ruby-on-Ruby environment.
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An unholy amalgam of therubyracer's V8 engine and emscripted-ruby to allow a truly sandboxed Ruby-on-Ruby environment. This is a terrible idea.


Add this line to your application's Gemfile:

gem 'ruby_on_ruby'

Or install it yourself as:

$ gem install ruby_on_ruby

As with any usage of therubyracer, you'll need to install v8 with your package manager or use the libv8 gem (currently ~> 3.11.8). See therubyracer's installation instructions for more information.


require 'ruby_on_ruby'
context =
context.eval "(1..10).inject(1) { |fact, n| fact * n }" # => "3628800"

I have questions!

What version of Ruby is running in the sandbox?

Ruby MRI 1.8.7

Can the host and guest environments interact?

Only through assignment and return values, at the moment. If emscripted-ruby provides a more complete API, so can I. For now, it's probably best to communicate over simple structures and do things like this:

context.eval "a = #{my_ruby_data.inspect}"
context.eval "result = process a"
result = eval(context.eval("result"))
# Horrible, right?  Right!

Is there Garbage Collection?

Nope. Available RAM ought be enough for anybody. (According to emscripted-ruby, "The Ruby garbage collector is currently incompatible with Emscripten, so we disable it completely. This causes memory leaks, but prevents crashes.")

Does this actually work?


Is it slow?

That depends. For your problem, is three orders of magnitude slower acceptable? Remember: Ruby scales! Just run it on three orders of magnitude more servers.

(Also, the same code may be up to an order of magnitude FASTER than native, non-sandboxed Ruby if you write it in JavaScript and run it with therubyracer, or with RubyOnRuby::Context#js_eval.)

Why would you make this?

No comment.


This code is released under the MIT License. You can use it however you like. I recommend that you not, and will not be held accountable if you do.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request
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