Re: [Geopriv] question on presrules

Enrique Izaguirre wrote:
> Hi,
> 
> according to RFC5025 there could be scenarios where the transformations 
> within a matching ruled whose action=block may filter the presence 
> document showed to the requestor.
> 
> E.g. this can happen when there are two matching rules, one that is 
> blocking and the other is allowing, and they have different 
> transformation elements. If RFC4745 is applied, the combined action is 
> "allow" and the combined transformation is a superset of both 
> "transformations".

Right. That is a possibility.

> 
> So, is the assumption that clients are smart enough so they will never 
> fall into the above case? or should a presence server prevent clients 
> from not doing such combination of rules?

Its a job of the UI on the client to prevent this. Normally its not a 
problem. The spec has this to say:

A consequence of this design is that the results of combining several
    authorization documents can be non-obvious to end users.  For
    example, if one authorization document grants permission for all
    users from the example.com domain to see their presence, and another
    document blocks [email protected], the combination of these will still
    provide presence to [email protected].  Designers of user interfaces
    are encouraged to carefully pay attention to the results of combining
    multiple rules.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   499 Thornall St.
Cisco Fellow                                   Edison, NJ 08837
Cisco, Voice Technology Group
[email protected]
http://www.jdrosen.net                         PHONE: (408) 902-3084
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