Re: Re: [Zope-CMF] Re: How do deal with cmfcatalog-wrapped objects?

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Just worked in the same area. I actually realised for our code, that  
we need two adapter, which reraises the question, how to reach for  
the real object for this adapters.

Two adapters:

Something like allowedRolesAndUsers is IMO a policy of the catalog or  
the overall system. Additionally there needs to be an adapter/ 
Interface to provide an object with the methods necessary for the  
selection of indices. This is more a descision of the developer of  
the object, or a particular application.

I think it is not a good solution, that the object-specific adapter  
inherits from the catalog-specific adapter.

So one ends up with a double wrapped object, where the outer catalog- 
specific adapter  needs to have access to the real object. How is  
this handled best? Is there a generic unwrap()-method?

__Janko


Am 07.04.2006 um 07:38 schrieb Andreas Jung:

> Both solution appear a bit "heavy" to me. I solved this issue for  
> TextIndexNG3 by adding generic support for wrapped objects by  
> introducing an
> IObjectWrapper interface which is checked by the indexer. Using  
> five:implements it is easy to attach this interface - if necessary  
> - to any
> wrapper class (including IndexableObjectWrapper@CMFCore). Writing  
> an adapter
> for adapting IndexableObjectWrapper to IObjectWrapper is trivial. I  
> think this solution is more straight forward and does not require  
> any changes
> to the CMF.
>
> -aj
>
> --On 31. März 2006 14:11:58 +0200 Philipp von Weitershausen  
> <philipp@xxxxxxxxxxxxxxxx> wrote:
> > 1. I think for the long term, IndexableObjectWrapper could be made a
> > decorator. This works as follows:
> >
> >   from zope.proxy import getProxiedObject
> >   from zope.app.decorator import Decorator
> >
> >   class IndexableObjectWrapper(Decorator):
> >
> >       def allowedRolesAndUsers(self):
> >           ob = getProxiedObject(self)
> >           allowed = {}
> >           for r in rolesForPermissionOn(View, ob):
> >               allowed[r] = 1
> >           localroles = _mergedLocalRoles(ob)
> >           for user, roles in localroles.items():
> >               for role in roles:
> >                   if allowed.has_key(role):
> >                       allowed['user:' + user] = 1
> >           if allowed.has_key('Owner'):
> >               del allowed['Owner']
> >           return list(allowed.keys())
> >
> > 2. In the short term we can apply the following trick
> > (IndexableObjectWrapper needs to be a new style class!):
> >
> >   from zope.interface import providedBy
> >   from zope.interface.declarations import  
> > ObjectSpecificationDescriptor
> >   from zope.interface.declarations import getObjectSpecification
> >   from zope.interface.declarations import ObjectSpecification
> >
> >   class IndexableObjectSpecification(ObjectSpecificationDescriptor):
> >
> >       def __get__(self, inst, cls=None):
> >           if inst is None:
> >               return getObjectSpecification(cls)
> >           else:
> >             provided = providedBy(inst.__ob)
> >             cls = type(inst)
> >             return ObjectSpecification(provided, cls)
> >
> >   class IndexableObjectWrapper(object):   # new-style!
> >       implements(...)  # it can implement as much as it wants
> >       __providedBy__ = IndexableObjectSpecification()
> >
> >       ...
>
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- --
Janko Hauser  email:  jhauser@xxxxxxxxx
              mobile: +49 1721 641552


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