From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-10-02T02:33:31+09:00
Subject: Re: cannot reverse string using drb :(

On Mon, Oct 1, 2012 at 7:24 PM, ajay paswan <lists@ruby-forum.com> wrote:
> "Jesús Gabriel y Galán" <jgabrielygalan@gmail.com> wrote in post
> #1078201:
>> On Mon, Oct 1, 2012 at 6:34 PM, ajay paswan <lists@ruby-forum.com>
>> wrote:
>>> # start up the DRb service
>>> object[0].each do |aa|
>>>
>>> puts "all string reversed"
>>>
>>> --
>>> Posted via http://www.ruby-forum.com/.
>>>
>>
>> If you check the DRB docs here
>> (http://ruby-doc.org/stdlib-1.9.2/libdoc/drb/rdoc/index.html), you
>> will see:
>   where is it written, sorry to be stupid, but may be am asking these
> questions as I am not comfortable or cannot read doc's any help
> please..?

Sorry, I pasted the first link, you have to click on the DRb module:

http://ruby-doc.org/stdlib-1.9.2/libdoc/drb/rdoc/DRb.html


>>
>>
>>
>> 1.9.2p290 :041 > remote_array.map! do |el|
>> 1.9.2p290 :042 >     if Array === el
>> 1.9.2p290 :043?>     el.map{|s| s.reverse}
>> 1.9.2p290 :044?>     else
> Its great to have so explained answer, but really I am unable to get the
> meaniing of codes, and what if I deal with a class's object?
>> 1.9.2p290 :045 >       el
>> 1.9.2p290 :046?>     end
>> 1.9.2p290 :047?>   end
>>  => [["tsrif", "dnoces", "driht", "htruof"], false]
>> 1.9.2p290 :048 > remote_array[1] = true
>>  => true
>>
>> Which as you see is a bit weird, but this is because the structure you
>> chose. I know this is just an example, but it shows that you should
>> model your server objects in such a way to make easy for the clients
>> to do the stuff.
> Sorry, but can I get an example Sir?

What I posted above is an example of the client code that goes with your server.

client.rb
#!/usr/bin/env ruby -w
# simple_client.rb
# A simple DRb client

require 'drb'

DRb.start_service

# attach to the DRb server via a URI given on the command line
remote_array = DRbObject.new nil, ARGV.shift

remote_array.map! do |el|
	if Array === el
		el.map{|s| s.reverse}
	else
    	        el
	end
end

puts "all string reversed"
remote_array[1]=true
puts "flag made true to finish"

> Its great to have so explained answer, but really I am unable to get the
> meaniing of codes, and what if I deal with a class's object?

Well, in order to understand DRb you have to know that when you call a
method on a remote object it's executed on the server. The result is
passed to the client. If you call methods on this result, they are not
passed anymore to the server:

remote_array = DRbObject.new nil, ARGV.shift

first_element = remote_array[0] # the method [] with argument 0 is
executed on the server. The result is an Array, which is marshalled
and sent to the client. first_element is a *copy* of the server's
array.

first_element[0] = "test"  # now, this method []= with arguments 0 and
"test" is executed only on the client, cause it's done against a
regular array, and not a DRbObject.


Jesus.