Minutes: XDI TC Telecon Thursday 2011-07-14

Following are the minutes of the unofficial telecon of the XDI TC at:

Date:  Thursday, 14 July 2011 USA

Time:  1:00PM - 2:00PM Pacific Time (20:00-21:30 UTC)

ATTENDING

Giovanni Bartolomeo

Bill Barnhill

Mike Schwartz 

Drummond Reed 

Joseph Boyle 

THE IDEARPAD LINK FOR TODAY IS:

     http://xdi.idearpad.org/36

1) UPDATE ON OPENXDI PROGRESS

Mike
 said that the project team finished implementing exclusion (processing 
of $not statements to exclude portions of the graph for $get requests). 
He explained that chaining $not (deny) conditions was relatively easy in
 comparison to chaining $do (allow) link contracts.

2) LINK CONTRACT POLICY EXPRESSION PROPOSAL

Mike sent a message to the list about a proposal for implementing policy expression/evaluation in link contracts:

  http://lists.oasis-open.org/archives/xdi/201107/msg00018.html

Mike
 explained that the first link contract implementation issue was 
synonyms between link contracts. Mike showed why the OpenXDI team needed
 to impose a rule that $is synonyms between $do contexts be canonical 
references to other link contracts. Drummond explained that this is in 
fact an ideal example of the need for canonical synonym semantics for 
$is he explained in a recent email to the list.

  http://lists.oasis-open.org/archives/xdi/201107/msg00011.html

Mike then walked us through his proposal for conditional statements in a link contract. The proposal includes:

$if context (as the parent for all conditions in the link contract)

$and and $or contexts (for grouping conditions)

$condition context (for concrete condition strings)

Evaluation operators for statements within conditions

Bill
 suggested that we consult with Hal Lockhart and Eve Maler because they 
have been dealing with policy expression languages for a long time. 
Drummond explained that he had coffee with Eve last week and discussing 
the intersection of UMA and XDI link contracts. He also thinks the TC 
should consult with Phil Windley at Kynetx because of the relevance of 
his KRL (Kynetx Rules Language).

Bill
 is working on a proposal for evalating conditions and policy 
expressions that he wants to finish implementing first before 
introducing. Bill's use cases have been taken from other domains and he 
is adapting them to XDI messages.

Mike
 suggested that we borrow as much as we can from LDAP because it has 
many years of history with attribute comparison (issues such as 
attribute type, case sensitivity, etc.)

3) LINK CONTRACT REFERENCES IN XDI MESSAGES

We need to close on the format for including the link contract reference in a message. See:

  http://lists.oasis-open.org/archives/xdi/201106/msg00041.html

  http://wiki.oasis-open.org/xdi/XdiMessagePatterns

We
 talked about whether $if statements in link contracts might affect the 
rule we agreed to last month that the requester must provide a reference
 to the link contract under which the requester has the rights to the 
data. Bill felt this is even more relevant because the same data may be 
available to the same requestor under multiple link contracts and the 
context may matter from a policy standpoint. Drummond agreed.

# DRUMMOND (and anyone else) - post proposed syntax for link contract references to the XdiMessagePatterns wiki page.

4) NEXT CALL

Drummond
 will be on vacation next week and not able to attend the call. We 
decided to skip next week's telecon, so the next call will be Thursday 
July 28 at the regular time.

------------

ONGOING ISSUES LIST

Each of these is a candidate for the agenda for future calls.

* DO WE NEED SEPARATE METAGRAPH WORDS FOR EQUIVALENCE AND INVERSION? (added 2011-06-30 - Giovanni)

This is an open issue because does not have a direct corallary in RDF.

* SYNONYM HANDLING (added 2011-06-30 - Giovanni)

This remains an open issue because it raises challenges with compatibility with RDF.

* TRANSACTIONAL INTEGRITY FOR XDI (added 2011-03-24)

Since 
 versioning, as one example, involves multiple transactions that must 
be  commited as a group, we will need to address transactional 
integrity.  Specifically, we need to define how this will be handled at 
the protocol  level, vs. the implementation level.

* PROPOSED CONSTRUCTS/OPERATORS FOR XDI

Discuss the following wiki page originally posted by Giovanni:

  http://wiki.oasis-open.org/xdi/XdiNewFoundation

* DICTIONARY STRUCTURE

Mike would like an example of the PDX dictionary as soon as we can do it.

*   EQUIVALENCE SEMANTICS

Close on whether we need an additional $ word that is the equivalent

of Higgins Personal Data Model (PDM)  semantics   of h:correlation,

which is not as strong as $is.

      http://lists.oasis-open.org/archives/xdi/201006/msg00036.html

* COOL URIS

Continue previous discussion about the use of standard RDF URIs in XDI:

  http://lists.oasis-open.org/archives/xdi/201006/msg00023.html