On Fri, 27 Oct 2006 00:33:17 -0400, Deepankar Sharma <deepankar.sharma@gmail.com> wrote:

Hello,

I am trying to use pb.Copyable to send some python objects back and forth between a client and server. I followed the documentation and quickly got some simple examples working. However i got stuck when i tried sending some python objects which are actually wrappers for stuff written in C. Here is an example of what i am trying to do

Class C (Wrapper for a c data structure)

Class B (inherits from class C and from pb.Copyable)

I have a lot of wrapper functions which give me instances of Class C. Trying to do c_instance.__class__ = B does not work. I somehow need to cast those instances into instances of class B so that the jellying/unjellying can take place. What does one do in such a situation ?

Instead of subclassing C, write a wrapper for it. Implement getStateFor on the wrapper. For example:

...

...

from twisted.spread import pb class X(object): ... def __init__(self, y): ... self.y = y ... class Z(pb.Jellyable): ... def __init__(self, x): ... self.x = x ... def getStateFor(self, jellier): ... return {'y': self.x.y} ... pb.jelly(Z(X(10))) ['__main__.Z', ['dictionary', ['y', 10]]] from twisted.spread import jelly def unjellyZ(jellier, state): ... return Z(X(y=pb.unjelly(state[1])['y'])) ... jelly.setUnjellyableForClass('__main__.Z', unjellyZ) pb.unjelly(['__main__.Z', ['dictionary', ['y', 10]]]).x.y 10

Jean-Paul

On Fri, 27 Oct 2006 00:33:17 -0400, Deepankar Sharma <deepankar.sharma@gmail.com> wrote:

Hello,

I am trying to use pb.Copyable to send some python objects back and forth between a client and server. I followed the documentation and quickly got some simple examples working. However i got stuck when i tried sending some python objects which are actually wrappers for stuff written in C. Here is an example of what i am trying to do

Class C (Wrapper for a c data structure)

Class B (inherits from class C and from pb.Copyable)

I have a lot of wrapper functions which give me instances of Class C. Trying to do c_instance.__class__ = B does not work. I somehow need to cast those instances into instances of class B so that the jellying/unjellying can take place. What does one do in such a situation ?

Instead of subclassing C, write a wrapper for it. Implement getStateFor on the wrapper. For example:

...

...

from twisted.spread import pb class X(object): ... def __init__(self, y): ... self.y = y ... class Z(pb.Jellyable): ... def __init__(self, x): ... self.x = x ... def getStateFor(self, jellier): ... return {'y': self.x.y} ... pb.jelly(Z(X(10))) ['__main__.Z', ['dictionary', ['y', 10]]] from twisted.spread import jelly def unjellyZ(jellier, state): ... return Z(X(y=pb.unjelly(state[1])['y'])) ... jelly.setUnjellyableForClass('__main__.Z', unjellyZ) pb.unjelly(['__main__.Z', ['dictionary', ['y', 10]]]).x.y 10

Jean-Paul