Presented at the Ruby Drink-up of Sophia Antipolis on the 6th of December 2011 by Nicolas Bondoux (@nicolas_bondoux).

1. DRb: an easy distributed objects framework for Ruby Ruby Drink-up of Sophia-Antipolis Nicolas Bondoux 06/12/2011

3. Transparent usage

4. No IDL; no need to share class definitions

5. DRb main classes are in standard library

7. Implemented network layers tcp, unix sockets, tcp+ssl

11. Acts as a proxy for a remote object

15. “drbunix:/tmp/toto” -> unix socket

17. DRbObject.new (obj, nil) will holds the ref of obj as well as the URI of current server (Drb.uri)

19. DrbObject example # server side require 'drb' MyURI = "druby://127.0.0.1:55555" $s = "Toto" class SimpleServer include DRb::DRbUndumped def s_DRbObject return DRbObject.new($s) end def s return $s end def s_clone return String.new($s) end end DRb.start_service(MyURI, SimpleServer.new) #on client side: require 'drb' MyURI = "druby://127.0.0.1:55555" server = DRb::DRbObject.new(nil,MyURI) s = server.s puts s puts s.class #String s.concat(" updated!") puts server.s_clone # display "Toto" s = server.s_DRbObject # DRb::DRbObject s.concat(" updated !") puts server.s_clone # display "Toto updated !"

21. Objects that cannot be marshalled are always passed as DRbObjects: Proc, IO, singletons, or any object referencing one of them

22. Objects that include DRb::DRbUndumped are always passed as DRbObject

24. Complex example with a Proc # server require 'drb' MyURI = "druby://127.0.0.1:55555" class Container def initialize @t = [] end def push o @t.push o end def each(&block) @t.each(&block) end end s = Container.new DRb.start_service(MyURI, s,{:safe_level => 1}) # client require 'drb' MyURI = "druby://127.0.0.1:55555" class Box include DRbUndumped attr_accessor :v def initialize v @v = v end end # needed to share local objects with the server: DRb.start_service s = DRbObject.new(nil, MyURI) a = Box.new(1) b = Box.new(2) s.push a s.push b s.each{ |i| puts i.class i.v = (i.v * 2) } # Box # Box # => block is called in local # => its parameters are converted back to local objects puts a.v # 2 puts b.v # 4

26. Unmarshaller converts a DrbObject on local object as a ref on local object

29. $SAFE variable should be set to 1 to prevent remote eval (can be set as parameter of the DRbServer)

32. Any Question ?