[Cosmo-dev] Sharing format questions

[Philippe Bossut]

Morgen Sagen wrote:
> I've always wanted us to be able to think of items as something akin 
> to a Photoshop image:  composed of a set of "layers" which can be 
> added or removed independently.  Each layer would represent one or 
> more related attributes plus their values.  For example, one layer 
> could include the "when-ness" of an event (start time, duration, 
> recurrence), another could include reminder alarms, and another the 
> title.  The user will want all of those layers published to Cosmo so 
> that all their own clients (Chandler, Scooby, etc.) will have access.  
> They will also want to give controlled access of these layers to other 
> Principals (accounts/groups/tickets).  Likewise, the other Principals 
> are going to want to pick and choose which layers they want to see 
> (you may have given me access to your reminder alarms, but I don't 
> want to download them).  And going back to the "setting personal 
> reminder alarms on items I don't have write-access to" requirement -- 
> we would need to be able to store these layers somewhere on Cosmo even 
> if the Principal doesn't have permission to modify the item itself.
>
> A long time ago I described these layers as "records", with multiple 
> records being composited into an item:
>
>    
> http://lists.osafoundation.org/pipermail/chandler-dev/2002-November/000181.html 

I really like the metaphor, makes a lot of sense to me. The fact that it 
shatters the notion of "item" can be a concern though. You wouldn't have 
to push the idea very much to move the granularity level of the repo 
from the item to the level of the "layer". For instance:
- Wouldn't you need GUIDs per layer with such a model? (one layer being 
potentially used in several items)
- If each layer has its own ACL, wouldn't that require Cosmo to do quite 
a bit of fancy filtering when getting a request for an item? (just to 
make sure that a client doesn't get unauthorized info for instance).

BTW, great thread. Extremely interesting exchange of ideas here.

Cheers,
- Philippe