[Zope3-Users] Re: event subscribers

[Florent Guillaume]

Pete Taylor wrote:
> hi all... question for any event subscriber gurus (or just anyone who knows
> more than me, which probably won't take much ;) )
> 
> i have a set of actions that i would like to have trigger off of a
> particular state in a workflow. in my unittest i can see that the workflow
> fires the event, but my subscriber doesn't pick up on it. similarly, the
> subscriber i have in zcml in the application proper does not respond when
> the workflow transition event is fired.
> 
> the functionality works if i explicitly call my subscription method against
> the event, but that only proves that the functionality of the code isn't
> broken...
> 
> the relevant zcml portion is as follows:
> <subscriber
> for="qarelease.interfaces.IRelease
> zope.app.workflow.stateful.interfaces.IAfterTransitionEvent"
> factory=".release.notifyTransition"
> />
> 
> the unittest subscribes with ztapi as follows:
> ztapi.subscribe((IRelease, IAfterTransitionEvent), None, notifyTransition)

As Jim mentioned, and as I discovered yesterday :), the ability to subscribe 
using a multi-adapter is not "stock" behavior of the basic event 
notification (which only sends one IEvent object), but actually behavior of 
the IObjectEvents, which have a special subscriber re-dispatching on both 
event.object and event, so that the multi-adapter subscribers can work.

What workflow framework are you using ? And what's 
qarelease.interfaces.IRelease ? Is it a transition or something else ?

That framework could be updated to do the same dance, if there's a clear 
"object" there. Or maybe some workflow event interfaces could be subclassed 
from IObjectEvent.

Florent

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