[Zope3-dev] Object Serialization Brainstorm

[Casey Duncan]

On Friday 21 December 2001 01:50 pm, Lennart Regebro allegedly wrote:
> From: "Casey Duncan" <c.duncan@nlada.org>
>
> > The key question is: Is it possible to design the system such that any
> > object visible in the ZMI could be arbitrarily (and automatically)
> > transformed or serialized into externally usable XML?
>
> Automatically? I can't see how. Even the example you give is not
> possible to do automatically, but require the object to know how to
> transform themselves itself into XML. How would you otherwise know that the
> data attribute is to be tranformed into a file with an encoding?

Actually you'd be surprised what you can do with introspection. Most data is 
just stored using simple types, so it can be handled, and object 
class/instance structures can be examined at run-time. Do an export of Zope 
objects in XML format to see what I mean. The problem with the export is that 
it is organized from the ZODB point of view, which isn't really that useful 
for anyting but packing and shipping data in and out of the ZODB.

Worst case, if introspection of the class structure fails, you can just stuff 
the pickled data as the value, but that has limited usefulness. That is where 
allowing a class or even an interface (or both) to define serialization 
overrides could come in handy. Hopefully the system could be designed such 
that you would only need to do it in special cases, or where reorganizing the 
data a special way is beneficial.

I think it can be done. I also think it is ambitious. I don't propose that 
Zope 3 has to implement this, what I do propose is that we maybe think of 
ways to implement Zope 3 now that will make this easier to implement later.

/---------------------------------------------------\
  Casey Duncan, Sr. Web Developer
  National Legal Aid and Defender Association
  c.duncan@nlada.org
\---------------------------------------------------/