[Zope3-checkins] SVN: Zope3/trunk/src/zope/app/dublincore/timeannotators.py Unwrap DCadapter in time annotators.

[Gary Poster]

On Feb 27, 2005, at 1:58 PM, Garrett Smith wrote:

> Gary Poster wrote:
>> Zope3/trunk/src/zope/app/dublincore/timeannotators.py Unwrap DCadapter
>> in time annotators.
>>
>>
>>
>> On Feb 25, 2005, at 7:10 PM, Albertas Agejevas wrote:
>>>
>>> ...Imagine a forum where anonymous
>>> users post comments.  Your suggestions imply that either DC write
>>> access will be public, or modification times will not be updated.
>>> This is bogus.
>>>
>>> A more plausible model would be if the event subscribers could be
>>> declared as "trusted" if they do system-level things, like updating
>>> the DC metadata or indexes.
>>
>> Albertas, your use case sounds reasonable.  On one hand, I think it
>> makes sense for a default Zope 3 app to *not* allow DC annotations if
>> you do not have write privileges to an object (for instance, if you
>> don't have have write access to an object it would seem surprising
>> that you could be last modifier to me, as an out-of-the-box
>> behavior); but on the other, it also might make sense for an app with
>> your use case to allow DC annotations.
>
> I see Albertas's point here. I think most people would want
> create/modified to always work, regardless of how they have their
> permissions set up.

Maybe so.  I don't feel strongly about it.

> This is also a function of event handlers *always* being called. Events
> are a nice way to add functionality, but once they're subscribed, they
> can be hard to work around.

Oh, yeah, good point. :-/

Isn't there some magic that if you subscribe None then that clears  
subscription for the exact combination of interfaces?...something like  
that?  Something even more surgical would be better for this sort of  
case.  But that might be workable.

>> Would making an override zcml registration of the DC annotation
>> subscriber in your package's zcml make sense for your app/package?  It
>> could make the DC subscriber a trusted subscriber ("trusted='yes'"),
>> which does precisely what you want AFAICT.  For the precise use case
>> you mentioned, you might even be able to register the trusted DC
>> subscriber only for the content types for which it makes sense (the
>> forum, I guess).
>
> I think implementing trusted event handlers is the way to go. Given
> they're adapters, it should be a matter of hooking up 'trusted' via the
> meta configure.
>
> It's certainly an inconsistency that normal adapters can be trusted,  
> but
> event handlers can't.

Maybe I'm missing a subtlety (handler vs. factory, maybe?) but this is  
already available on the HEAD, if I understand you.

http://127.0.0.1:8080/++apidoc++/ZCML/ 
http_co__sl__sl_namespaces.zope.org_sl_zope/subscriber/index.html

(or see zope.app.component.metadirectives.ISubscriberDirective)

I think I've used these (trusted subscribers)...

Gary