Discovering Data Collections Note

[Patrick Dowler]

A coupe of comments on the note:

In the second paragraph of 2.1.2 you have the wrong standardID for SIA
(should be #query-2.0).

In that same paragraph, the recommendation is to insert "aux" between
the tag and the version. That effectively means that the fragment is
now a parseable construct as clients will have to be able insert and
extract the "aux" nature of the standardID. So at first glance it
seems preferrable to put the "aux" string at the beginning or the end
rather than in the middle. I experimented a bit and there are a
variety of separator characters one can use in a URI fragment without
breaking a standard URI parser, eg.


groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0@aux").getFragment()
===> query-2.0 at aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0~aux").getFragment()
===> query-2.0~aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#aux~query-2.0").getFragment()
===> aux~query-2.0
groovy:000> new URI("ivo://ivoa.net/std/SIA#aux:query-2.0").getFragment()
===> aux:query-2.0
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0&aux").getFragment()
===> query-2.0&aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0*aux").getFragment()
===> query-2.0*aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0;aux").getFragment()
===> query-2.0;aux

some that are legal but too cumbersome:

groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0(aux)").getFragment()
===> query-2.0(aux)
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0[aux]").getFragment()
===> query-2.0[aux]

and some that I expected to not be valid and they were not:

groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0#aux").getFragment()
Illegal character in fragment at index 32: ivo://ivoa.net/std/SIA#query-2.0#aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0$aux").getFragment()
Unknown property: aux
groovy:000> new URI("ivo://ivoa.net/std/SIA#query-2.0%aux").getFragment()
Malformed escape pair at index 32: ivo://ivoa.net/std/SIA#query-2.0%aux

As I mentioned in Trieste, I have created ~20 data collections and do
intend to use this to connect them to services, so +1 on the basic
idea. I'd like to see it being easier to detect aux capabilities so at
a minimum the "aux" string should be at the beginning or end rather
than the middle. I'm less sure if there is value in making it
separable by specifying a special separator character.

On reading the note, I did consider another option, but will bring it
up in a separate message.

Pat

On 4 November 2016 at 03:35, Markus Demleitner
<msdemlei at ari.uni-heidelberg.de> wrote:
> Dear Colleagues,
>
> Also in the name of this WG, I'd like to bring the note on discovering
> data collections on the road to endorsement.  Among other reasons,
> Registry Interfaces 1.1 will probably use it in saying how to
> registry RegTAP registries, so it'd be great if we could get
> endorsement before RI 1.1 reaches the Exec.
>
> With that in view, I've reviewed the note and, in the end, did quite
> a few changes; below is the volute log since publishing the note (cf.
> http://volute.g-vo.org/svn/trunk/projects/registry/discovercollections)
>
> The change log says, shorter:
>
> * Now encouraging extra parameters in access URLs where appropriate.
> * No longer requiring auxiliary capabilities to be plain vr:Capability.
> * Updates for depreciation of served-by in VOResource 1.1.
> * Removed secion on GloTS.
>
> Before I submit it to the doc repo (scheduled for 2016-11-11): Does
> anyone have comments or opinions we should clarify within the WG
> before going to the TCG?  If you don't want to build the doc
> yourself, there's a formatted PDF at
>
> http://docs.g-vo.org/discovercollections.pdf
>
> Thanks,
>
>         Markus
>
> ------------------------------------------------------------------------
> r3685 | msdemlei | 2016-11-04 11:23:25 +0100 (Fri, 04 Nov 2016) | 3 lines
>
> discovercollections: bumping version.
>
>
> ------------------------------------------------------------------------
> r3684 | msdemlei | 2016-11-04 11:22:00 +0100 (Fri, 04 Nov 2016) | 3 lines
>
> discovercollections: removing section on GloTS.
>
>
> ------------------------------------------------------------------------
> r3683 | msdemlei | 2016-11-04 11:19:55 +0100 (Fri, 04 Nov 2016) | 3 lines
>
> discovercollections: Editorial changes.
>
>
> ------------------------------------------------------------------------
> r3682 | msdemlei | 2016-11-04 11:00:07 +0100 (Fri, 04 Nov 2016) | 6 lines
>
> discovercollections: served-by is deprecated by VOResource 1.1, use IsServedBy
> in the future.
>
> Also, some editorial changes.
>
>
> ------------------------------------------------------------------------
> r3681 | msdemlei | 2016-11-04 10:40:15 +0100 (Fri, 04 Nov 2016) | 5 lines
>
> discovercollections: No longer requiring auxiliary capabilities to be
> plain vr.Capability
>
> (also, some editorial changes)
>
> ------------------------------------------------------------------------
> r3675 | msdemlei | 2016-11-03 16:51:15 +0100 (Thu, 03 Nov 2016) | 4 lines
>
> discovercollections: Adding a piece on using in-URL parameters to constrain
> results to the data collections described.
>
>
> ------------------------------------------------------------------------
> r3674 | msdemlei | 2016-11-03 16:22:44 +0100 (Thu, 03 Nov 2016) | 4 lines
>
> discovercollections: Some editorial changes in preparation for making this
> an PEN.
>
>
> ------------------------------------------------------------------------
> r3546 | msdemlei | 2016-09-13 19:54:39 +0200 (Tue, 13 Sep 2016) | 3 lines
>
> discovercollections: moved SIA 2.0 aux cap id here from SimpleDALRegExt.
>



-- 
Patrick Dowler
Canadian Astronomy Data Centre
Victoria, BC, Canada