[Zope3-Users] event subscribers

[Jim Fulton]

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)
> 
> this seems, from both srichter's book and philiKON's book to be the 
> right way to do this (moving from ztapi.handle to ztapi.subscribe since 
> handle is being deprecated). 
> 
> does anyone have any experience in attempting to do anything like this?

Normallym event subscribers are single-object adapters.  In some cases,
we have subscrobers that redispatch on multiple objects.  For example,
object events have a subscriber that redispatches events based on the
object and event.  You expect something similar to be going on for workflow
events, but I suspect there isn't.

Jim

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