[Zope-dev] Storing part of an object on the file system

[Steve Alexander]

Andy McKay wrote:

> Ok whack idea #34... Well sort of, the idea was sparked by ExtFile (yes its
> all his fault honest). We want to have files on the file system for many
> reasons which I won't go into now, just take it for granted. But we also
> want some of the objects information to be in the standard data.fs, so we
> can catalog it use acquisition provide a simple interface to it and so on.
> So far you are saying thats ExtFile and you are right.
> 
> But we want to extend it to any object anywhere, instead of storing the data
> attribute in the object and pickling it in the ZODB I want to be able to
> store the data attribute on the file system. This gives us loads of
> advantages we also thought this would be extremely useful to other people.
> We've bounced around ideas on how to do this and here the only two so far:

Use ZPatterns. This is exactly what ZPatterns is designed for; choosing
different places to store and retrieve different attributes.

> -    we could overload the data attribute with a class that on Pickling into
> the ZODB instead writes it on to the filesystem...

You can easily do this with ZPatterns.

> -    we could in the ZODB put a hack to say if pickling something with so
> and so attribute do this instead...

You can easily do this with ZPatterns.

> I feel like this something I should just not be doing, but it would be great
> if I could get it work...

Take a look at the SkinScript reference.

http://www.zope.org//Members/pje/Wikis/ZPatterns/SkinScriptSyntax

--
Steve Alexander
Software Engineer
Cat-Box limited
http://www.cat-box.net