[Zope3-Users] Re: RFC 4122 UUIDs

[Benji York]

Derek Richardson wrote:
> I believe that that will not guarantee a *universally* unique id, but 
> only an id unique within that ZODB. Am I wrong?
> 
> The RFC prescribes a specific algorithm for generating universally 
> unique IDs.

Of course, they are only "universally unique" in a probabilistic way.

It wouldn't be difficult to salt the integer IDs such that they generate 
UUIDs that are as likely as any other to be unique.  Something like this 
would work:

import uuid
int_id = 42
salt = 0x32352352353243263235235235324326
print uuid.UUID('%X' % (int_id ^ salt))

Another option would be to create an IOBtree to map each object's intid 
to a randomly generated UUID (generated by the uuid.uuid1 method from 
the earlier referenced module).
-- 
Benji York
Senior Software Engineer
Zope Corporation