From: "Stephan Kämper" <Stephan.Kaemper@...>
Date: 2004-01-04T09:01:47+09:00
Subject: More from using DRb and observers...

Andre Nathan wrote:
> Have a look at the thread starting at ruby-talk:88698.
> 
Hi all,

Andre, thanks for the link to the earlier discussion.

Now the 'compressed' notifier looks like this...

require 'drb'
require 'drb/observer'

class Notifier
   include Observable
   include DRb::DRbUndumped

   def change( i )
     puts "Changing: #{'%2d' % i}"
     changed( true )
     notify_observers( Time.now, i )
   end
end

DRb.start_service( 'druby://tao:4711', Notifier.new )
puts DRb.uri
DRb.thread.join

....and the client like that:

require 'drb'

class Client
   include DRb::DRbUndumped

   def initialize( observed )
     observed.add_observer( self )
   end

   def update( *args )
     puts "!!!"
     p *args
   end
end
DRb.start_service
notifier = DRbObject.new( nil, 'druby://tao:4711' )
d = Client.new( notifier )

notifier.change( rand( 10 ) )

Now, running both programs once works fine.

For Notifier:
[979] stk@tao ~/devel/util: ruby Notifier.rb
druby://tao:4711
Changing:  4


For Client:
[974] stk@tao ~/devel/util: ruby Client.rb
!!!
Sun Jan 04 00:32:53 CET 2004
6
Great! And thanks again for the help!


Unfortunately starting the client a second time it get an error I 
(partially) don't understand.

The Server output continues with:

Changing:  1


The Client output is this:
Sun Jan 04 00:40:11 CET 2004
4
[974] stk@tao ~/devel/util: ruby Client.rb
(druby://tao:4711) /usr/local/lib/ruby/1.8/drb/drb.rb:705:in `open': 
druby://tao:33324 - #<Errno::ECONNREFUSED: Connection refused - 
connect(2)> (DRb::DRbConnError)
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:698:in `each'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:698:in `open'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:1084:in `initialize'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:1067:in `new'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:1067:in `open'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/drb/drb.rb:1014:in `method_missing'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/observer.rb:185:in `notify_observers'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/observer.rb:184:in `each'
         from (druby://tao:4711) 
/usr/local/lib/ruby/1.8/observer.rb:184:in `notify_observers'
         from (druby://tao:4711) Notifier.rb:11:in `change'
         from Client.rb:19
[974] stk@tao ~/devel/util:

Now, why does it say >>> druby://tao:33324 <<< in the 1st line of th output?
And how can I stop this?

BTW, 'ruby -v' yields: ruby 1.8.1 (2003-12-25) [i686-linux].

Happy rubying!

Stephan