Install now with sudo gem install classroom

ClassRoom (RubyForge project) is a project to develop a distributed 'class server' powered by DRb that I have been working on. Let's skip long explanations and jump into code. First, we'll create a very basic "Dog" class with some basic features:

class Dog
  attr_accessor :name

  def self.count
    @@count ||= 0
  end

  def initialize(options)
    self.name = options[:name]
    @@count ||= 0
    @@count += 1
  end
end

Next, we'll create a program that can use Dog via ClassRoom:

require 'rubygems'
require 'classroom'

class_server = ClassRoom::Client.new('classroom://:2001')
class_server.add_class(IO.read('dog.rb'))
class_server.load_class(:all)

puts "There are #{Dog.count} dogs"
fido = Dog.new(:name => "Fido")
puts "There are #{Dog.count} dogs"
rufus = Dog.new(:name => "Rufus")
puts "There are #{Dog.count} dogs"
puts "fido's name is #{fido.name}"

# => There are 0 dogs
# => There are 1 dogs
# => There are 2 dogs
# => fido's name is Fido

Take care to notice that at no point is dog.rb actually included/'require'd. The Dog class doesn't exist until line 6. What happens is that the script connects to a ClassRoom server, uploads the Dog class to it, and then loads all of the classes from the ClassRoom server to be used as if they're local (they're not, they run direct from the ClassRoom server, all the load does is create proxy classes).

If this looks a little familiar, it's because DRb provides some of this functionality. But DRb only lets you use an object remotely, whereas ClassRoom lets you use classes and objects naturally as you normally would. Class methods, object methods, initializers, etc, all work as you'd expect.

You can upload classes (or Modules or entire class hierarchies!) to a ClassRoom server on-the-fly and use them from any applications you like. You can, if you like, change the functionality of classes mid-execution and all of your client applications will use the new classes and methods seamlessly. Alternatively, you might want to load up classes from the server end only and allow them to be used by various applications. It's (mostly) up to you, and it's (mostly) seamless.

ClassRoom is VERY, VERY ALPHA right now, but if you know your bindings from your singletons, have a play with it. If you install the gem, there are about ten example demonstration scripts (including the server.rb you'll need) in the /examples folder where the gem is installed. These should fill in most of the gaps. In case you want to get experimenting immediately, here's a basic server:

require 'rubygems'
require 'classroom'

url = ClassRoom::ClassServer.prepare
# ClassRoom::ClassServerContainer.add_class(IO.read('someclass.rb')) 
puts "ClassRoom server running at #{url}"
ClassRoom::ClassServer.start

Have a play and leave some comments. I want to open this up even more next.