[sr-dev] git:master: xcap_server: support parsing oma pres-rules auid

[Iñaki Baz Castillo]

2010/9/29 Daniel-Constantin Mierla <miconda at gmail.com>:
>> does xcap-server already support oma pres-rules and resource-list or is
>> it on the roadmap?
>
> xcap server is just for storage and manipulation of xml xcap docs.

Unfortunatelly this is not entirely true. For example, the oma-icon
XCAP application (storage of an icon in XML format) requires a lot of
logic in the XCAP server, why?:

- Alice does a XCAP/HTMP PUT of his avatar/icon (a XCAP/XML document)
to the XCAP server.

- The Alice sends a PUBLISH (event "presence") to the presence server.
According to OMA specs, this PUBLISH can contain a <icon> element with
a link to the XCAP/XML document, something like:

    <icon>http://xcap.mydomain.org/org.openmobilealliance.pres-content/users/sip:alice@mydomain.com/oma_status-icon/index</icon>

- Bob is a watcher allowed by Alice for event "presence". Bob receives
the NOTIFY containing such <icon> link.

- Bob then performs a XCAP/HTTP GET for that URL.

- The XCAP server receives the GET from Bob and now, the XCAP server
MUST check if Bob is allwoed or not to see Alice's status. What does
it *mean*? It means that the XCAP server MUST get the 'pres-rules'
document of Alice and inspect if Bob is allowed or not. Such
'pres-rules' document could contain (MUST in OMA specs) an absolute
HTTP reference to Alice's 'resource-lists' document (as permissions
are based on sublists. Again, 'resource-lists' document can contain
(or MUST in OMA specs) absolute HTTP references to the
'resource-lists' document itself (yes, with depth 3 or 4, *really*).

This means that the XCAP server MUST behave as a SIP presence server
in order to allow or deny the icon of user B to user A. Painful? Yes.


> Presence modules are able to deal with pres-rules, not sure to what extent the oma additions.

Read OMA-WP-PRS_1_1_Implementation_Guidelines-20081209-A.pdf and
OMA-WP-XDM_1_1_Implementation_Guidelines-20081209-A.pdf.

There is clear how unclear the specs are. But basically, as I've said
above, pres-rules document contains absolute HTTP links to
resource-lists document, and resource-lists document contains absolute
HTTP links to itself.


Regards.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>