[occi-wg] Fwd: Link Relations: up/down vs parent/child vs ancestor/descendant etc.

[Sam Johnston]

Evening all,
FYI - there's been some discussion about OCCI dependencies on other lists
but I've been avoiding cross-posting given the audiences are quite
different. The latest is about wiring resources together using generic link
relations as it's preferable that we avoid rolling our own standards where
we can use ones that already exist.
Sam

---------- Forwarded message ----------
From: Sam Johnston <samj at samj.net>
Date: Tue, Sep 8, 2009 at 7:08 PM
Subject: Link Relations: up/down vs parent/child vs ancestor/descendant etc.
To: Atom Syntax <atom-syntax at imc.org>, HTTP Working Group <
ietf-http-wg at w3.org>


Evening all,
I am busy designing a protocol for cloud computing[1] and want clients to be
able to discover children of a given resource in order to navigate a tree
structure. I had been considering defining a new "collection" link relation
but then found draft-divilly-atom-hierarchy<http://tools.ietf.org/html/draft-divilly-atom-hierarchy>
which
defines a "down" relation.

My concern is that the terms "up" and "down" are ambiguous in this context
and indeed we may end up defining [URI] relations for "up" and "down" as
state changes for network resources. Furthermore there has been come
commentary/confusion of late around the use of multiple attributes (e.g. "up
up up") and now seems as good a time as ever to clarify given we have the
link relation I-D and HTML 5 WD on the table at the IETF and W3C
respectively.

I wonder whether it would be possible to instead use "parent" and "child"
(for first generation relationships) or "ancestor" and "descendant" (for
more generic n-generation relationships, where n is specified as an
attribute like "level=2")? This is simple and self-describing and could
resolve the issue once and for all. Alternatively the terms could be
abbreviated to "asc" and "desc" respectively (as in "ascend" and "descend").

I also wonder whether "collection" isn't a bad idea anyway - consider a
resource describing a bookshelf where the collection consists of books.

Sam

1. http://www.occi-wg.org/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.ogf.org/pipermail/occi-wg/attachments/20090908/25398cab/attachment.html