At Tue, 18 Nov 2008 06:13:46 -0500,
Ed Summers [EMAIL PROTECTED] wrote:
Thanks for bringing this up Erik. It really does seem to be
preferable to me to treat these tiles as web resources in their own
right, and to avoid treating them like resources that need to be
routed to with OpenURL. It is also seems preferable to leverage
RESTful practices like using the Accept header.
I wonder if it would improve downstream cache-ability to push parts of
the query string into the path of the URL, for example:
http://an.example.org/ds/CB_TM_QQ432/4/0/899/1210/657/1106
Which could be documented with a URI template [1]:
http://an.example.org/ds/{id}/{level}/{rotate}/{y}/{x}/{height}/{width}
I guess I ought to read the paper (and refresh my knowledge of http
caching) to see if portions of the URI would need to be optional, and
what that would mean.
Still, sure is nice to see this sort of open source work going on
around jpeg2000. My nagging complaint about jpeg2000 as a technology
is the somewhat limited options it presents tool wise ... and djatoka
is certainly movement in the right direction.
It might improve cache-ability: my understanding (not checking sources
here) is that many caches do not cache GETs to URIs with query parts,
although it is allowed. However: query parameter order does matter, so
an explicitly ordered URI template could certainly prevent the problem
of:
http://example.org/?a=1b=2
being considered a different resource than:
http://example.org/?b=2a=1
If you read rest-discuss, there have been discussions of image
manipulation with URI query parameters/paths.
http://article.gmane.org/gmane.comp.web.services.rest/6699
http://article.gmane.org/gmane.comp.web.services.rest/8167
There seem to be advantages to both methods (query parameters/paths).
There is the further possibility of using path parameters [1], which
seems a pretty natural fit, but not widely used:
http://an.example.org/ds/{id};level={level};rotate={rotate};y={y};x={x};height={height};width={width}
Additionally, I think that reading about how Amazon does (mostly) the
same thing would be useful:
http://www.aaugh.com/imageabuse.html
I think that the library community could contribute to possible work
in standardizing, to some extent, image manipulation with URIs; but I
do feel that using OpenURL will slow or prevent uptake.
best,
Erik Hetzner
1. http://www.w3.org/DesignIssues/Axioms.html#matrix
;; Erik Hetzner, California Digital Library
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