[Zope3-dev] Re: Correctly sending ObjectModifiedEvents [was SVN: zope.webdav/trunk/src/zope/webdav/ Emit an ObjectModifiedEvent on successfully modifying a property with]

[Michael Kerrin]

Philipp von Weitershausen wrote:
> Michael Kerrin wrote:
>> Log message for revision 72694:
>>   Emit an ObjectModifiedEvent on successfully modifying a property 
>> with   the proppatch method.
>
> ...
>>  
>> +        if changed:
>> +            zope.event.notify(ObjectModifiedEvent(self.context))
>> +
>
> Just emitting an ObjectModifiedEvent like that is pretty useless, IMO. 
> With this you have no clue
>
> - whether the object or the object's annotations were modified
>
> - which properties of which schema were modified.
>
> The good news is that the ObjectModifiedEvent API actually supports 
> this kind of stuff, you just need to use it:
>
>   info = Attributes(ITheSchema, 'foo', 'bar', 'blergh')
>   notify(ObjectModifiedEvent(obj, info))
>
> (Attributes is importable from zope.lifecycleevent). Note that the 
> object must not necessarily provide ITheSchema, it could also be that 
> the ITheSchema(obj) adapter was changed (this is useful when sending 
> modified events for annotation adapters like IZopeDublinCore).
>
Very interesting - I never even knew you could do this :-)

All modifications made by the PROPPATCH will be done via the adapter  
lookup you just mentioned so it is really nice that this is supported.
> Unfortunately, not many places in Zope 3 itself are good examples of 
> this. In fact, not even formlib sends this extra information along 
> with the events, something I've been meaning to report and fix. 
> (Thanks for reminding me to do so :)).
Thanks for the tip, I will definitely update webdav to use it.

Michael