We've been developing a video sharing product for Plone 3 / 4 which
uses dexterity, but we've had few problems related with dexteritys
missing support for UIDs. We're implementing oEmbed interface for our
package (http://www.oembed.com) and we need to have unique URL what
oembed provider can use to provide data to clients. We could use the
contents original URL, but then we have problems with broken links if
content is moved to other location so using something like UIDs is
preferred option.

I googled around for solutions and found lengthy discussions about
using IntIds with dexterity to create UIDs and I tried to take that
approach, but found myself being amazed how things were not working in
the way I thought they would. On package reinstalls sometimes
generated UIDs disappeared and IntId utility disappeared regularily
from site root. As I ran into trouble with IntId approach I developed
my own UID generator and created new index to portal_catalog for it.
This solution is working just fine, but I still think this behaviour
should be provided by the framework and I'd like to know if I've just
been staring same code too long and can't see how it is really
supposed to be done?

I'd appreciate any opinions for this subject.

- pingviini

2009/11/25 pingviini <jukka.ojani...@gmail.com>:

Dexterity objects have UIDs via zope.intid. They just don't have a
UID() method that returns an Archetypes UID string.

That shouldn't happen. If it does, it's a bug, which I'd ask that you
file. The above is too vague to diagnose, unfortunately.

It's supposed to be done by intids. They're not catalogued by default,
though perhaps they should be?

Note that intids (like AT UIDs) are not stable across sites, i.e. if
you export/import you are liable to get a different UID. For that,
you'd need hash based GUIDS, which is different. I'm sure there's a
Zope/Python package for that somewhere already.

Martin

    Martin> Note that intids (like AT UIDs) are not stable across sites,
    Martin> i.e. if you export/import you are liable to get a different
    Martin> UID. For that, you'd need hash based GUIDS, which is
    Martin> different. I'm sure there's a Zope/Python package for that
    Martin> somewhere already.

the uuid module in python standard lib allows for various kind of GUIDS,
both "stable" and "random", created using some kind of entropy generator.