[Zope-dev] Events in the core

[Florent Guillaume]

[Keeping only zope-dev, not zope-cmf]

Martijn Faassen wrote:
> Florent Guillaume wrote:
> 
>> I'd like to revive this discussion about having events in the core.
>>
>> Sidnei even mentionned getting them in Zope directly,
>> http://dev.zope.org/Wikis/DevSite/Proposals/IncludeEventsInCore
>>
>> I'm all for it, and would really help many people.
>>
>> It would be awesome if a minimal implementation could be compatible with
>> Zope 2.7.4, maybe as an addon product. But there needs to be a few hooks
>> in the core (object create/move/clone/delete).
>>
>> Could we try to move together on this ?
> 
> 
> Five already has had some work done in backporting the Zope 3 event 
> system, so it'd be nice to be able to reuse this. I'd be willing to work 
> together on this. I tried reasonably hard (there are at least some tests 
> :) to get Zope to send the right Zope 3 style events on creation, copy 
> and move.
> 
> If we backport the Zope 3 story, we'd need to worry about importing 
> issues. If we backport Zope 3 events, what package will they live in? 
> How will this relate to Five? What other packages does this draw in 
> (zope.interface definitely)? Etc.
> 
> Five can make something send Zope 3 events right now by just another 
> ZCML statement, though it drives a monkeypatch underneath..

The two options we have are quite different:

The model in Products/Event and Products/EventListenerTool is geared 
toward local definition of listeners and rules for dispatch (if needed, 
the tool could easily be divorced from CMF by the way).

Zope 3's event model (and the Five backport) is first a global event 
service, and global subscribers that may look in context-dependent 
places for specific logic to dispatch events.

So we have to chose. Jim added a comment in 
http://dev.zope.org/Wikis/DevSite/Proposals/IncludeEventsInCore saying 
(unsurprisingly) that he'd rather use the Zope 3 event system.

I'll work in that direction.

Martijn asked important question:

 > If we backport Zope 3 events, what package will they live in?
 > How will this relate to Five? What other packages does this draw in
 > (zope.interface definitely)? Etc.

If we want that to work with Five and Zope 2.7, will there be no way to 
use the current Zope Interface module ? Will we have to use the Zope 3 
one ? Can they be used together in a compatible manner ?

If someone has clues...

Florent

-- 
Florent Guillaume, Nuxeo (Paris, France)   CTO, Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg at nuxeo.com