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From: Sausheong Chang on 9 Dec 2009 09:39
Hi

I have a slightly different problem. I have an array stored in the
object:

class Room
include DRb::DRbUndumped
attr_accessor :name
attr_accessor :game
attr_accessor :observers

def initialize(name=nil)
@game = nil
@observers = []
@name = name
end
end

And the object is stored at the 'server'. At the 'client' I got the
object and is able to modify the @name instance variable at the
'server'. However when I tried to add objects to the @observers array it
doesn't seem to appear at the 'server'. What could be wrong?


Brian Candler wrote:
> Master Marv wrote:
>> if a client modifies the status variable of a class instance in the
>> array it does not get changed.
>>
>> dump = DRbObject.new nil, ARGV.shift
>> myclass = IEB_wrapper1.new
>> dump.push myclass
>> dump[0].status = "Hello"
>> p dump[0].status => results in "ready" not in "Hello"
>>
>> how can i modify the status of my class in the array on the drb server?
>
> class IEB_wrapper1
> include DRbUndumped
> end
>
> This means that instead of passing across a *copy* of the object (made
> using Marshal.dump and load), it will pass across a DRb *proxy object*.
> All operations made on that proxy are sent across as remote method calls
> and therefore made on the server.
>
> I wrote a document called "DrbTutorial" on rubygarden.org, which
> unfortunately is long since gone. You might be able to find a cached
> copy somewhere.

--
Posted via http://www.ruby-forum.com/.

From: Brian Candler on 9 Dec 2009 10:21
Sausheong Chang wrote:
> I have a slightly different problem. I have an array stored in the
> object:
>
> class Room
> include DRb::DRbUndumped
> attr_accessor :name
> attr_accessor :game
> attr_accessor :observers
>
> def initialize(name=nil)
> @game = nil
> @observers = []
> @name = name
> end
> end
>
> And the object is stored at the 'server'. At the 'client' I got the
> object and is able to modify the @name instance variable at the
> 'server'. However when I tried to add objects to the @observers array it
> doesn't seem to appear at the 'server'. What could be wrong?

Try this:

@observers = [].extend DRb::DRbUndumped

I think the same thing is happening one level down: although the Room
instance stays where it is, when you make a call across the net to
room.observers the return value is a *copy* of this array.

Another solution is to remove the attr_accessor for observers
completely, and instead implement separate methods for what the client
really needs to do - e.g. add an observer, remove an observer, iterate
across observers.
--
Posted via http://www.ruby-forum.com/.

From: Sausheong Chang on 9 Dec 2009 11:20
Thanks! That worked, though a bit messier than I would have liked it.


Brian Candler wrote:

>
> Try this:
>
> @observers = [].extend DRb::DRbUndumped
>
> I think the same thing is happening one level down: although the Room
> instance stays where it is, when you make a call across the net to
> room.observers the return value is a *copy* of this array.
>
> Another solution is to remove the attr_accessor for observers
> completely, and instead implement separate methods for what the client
> really needs to do - e.g. add an observer, remove an observer, iterate
> across observers.
--
Posted via http://www.ruby-forum.com/.

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