Question

I would like to include module in my Application Controller based on instance variable.

I’ve got something like this right now:

class ApplicationController

  before_filter :include_module

  def include_module
    @@site = "foo"
    class_eval{ include @@site.classify.constantize::Bar }
  end
end

However, I would like to make this snippet thread safe. Is it possible? What I would like to achieve, is on each request load module, which name depends on some variable.

Answer 1

AFAIK Rails is thread safe and on MRI will be single threaded. However context matters. Are you running MRI or JRuby? I suggest you read through the following 3 once

http://m.onkey.org/thread-safety-for-your-rails

http://yehudakatz.com/2010/08/14/threads-in-ruby-enough-already/

http://blog.headius.com/2008/08/qa-what-thread-safe-rails-means.html

EDIT: If your rails application is single threaded then your variables are thread safe. I should have added that before. In that context Rails is thread safe.