From: Eric Hodel <drbrain@...7.net>
Date: 2006-04-11T03:10:21+09:00
Subject: Re: do i have to use DRbUndumped?

On Apr 10, 2006, at 8:23 AM, holy sinner wrote:

> i am currently using Ruby 1.8.4 and DRb 2.0.4, and i am stuck with  
> some marshalling problem
> related to tuplespace. this is my hello world code using tuplespace
>
> ---
> #HelloWorld.rb
> require "rinda/ring"
>
> class HelloWorld
> #	include DRbUndumped
> 	def initialize(str)
> 		@str = str
> 	end
> 	def _dump(dumpDepth)
> 		@str
> 	end
> 	def HelloWorld._load(srcString)
> 		HelloWorld.new(srcString)
> 	end
> 	def to_s
> 		@str
> 	end
> end
>
> DRb.start_service
>
> ringServer = Rinda::RingFinger.primary
> tupleSpace = ringServer.read([:name, :TupleSpace, nil, nil])[2]
> tupleSpace = Rinda::TupleSpaceProxy.new tupleSpace
>
> tupleSpace.write(["helloWorldObject", HelloWorld.new("Hello World!")])
>
> aHelloWorldObject = tupleSpace.take(["helloWorldObject", nil])
> puts aHelloWorldObject[1]
>
> #DRb.thread.join
>
> ---
>
> my problem is that _dump doesn't work, because the HelloWorld  
> object gets converted into DRb::DRbUnknown, which can not be  
> converted into tuple to be inserted into the tuplespace. it does  
> not occur if i use DRb::DRbUndumped, but i think using  
> DRb::DRbUndumped is rather unsecure if i try using read instead of  
> take to get the object out of the tuplespace.

Unsecure?  Why?

If you're worried about losing the object due to the taking process  
dying use a TupleSpaceProxy.  It ensures that the object won't get lost.

> the question is:
>  - what's wrong with my _dump (and _load) ? do i have to use  
> DRb::DRbUndumped ?

You should really use marshal_load and marshal_dump.   
DRb::DRbUndumped must be used on objects that don't have their class  
present on all ruby processes in the system.

>  - do i have to use Rinda::Ring to work with Rinda::TupleSpace ?

No.  Rinda::Ring lets you find DRb services easily.  It is zeroconf  
for DRb.

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

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