IVOA VOTable signature issue

[Marco Molinaro]

Dear DAL-ers & Apps-ers,

2017-03-23 10:40 GMT+01:00 François Bonnarel
<francois.bonnarel at astro.unistra.fr>:
> Hi Pierre, all,
>
> 1 ) Having the standardID of the protocol in an INFO tag of the response is
> definitely a good idea.

Regarding this topic, Pierre lighted a discussion at last week's
ASTERICS DADI Tech Forum.
The general opinion was that it's a good idea indeed, and that an INFO
element (as a <votable>
child) could take care of this information.

Some hesitation whether this info should be <resource> related was
expressed, but it seems
that, for now at least something like:

<info name="STANDARD_ID" value="ivo://ivoa.net/TAP"/>

may be ok.

Now, while looking at DALI-1.1, I realized that it's already there
(§4.4.3) and it's there since DALI-1.0.

The changes to make would be
- move it from a MAY clause into some more robust recommendation (not
a MUST, of course)
- define if it should be "standardID" (as it is now in the text) or
"STANDARD_ID",
   as proposed by Markus following the QUERY_STATUS format
- consider if we have to move that <info> from being child of
<resource> (DALI-1.1 currently)
  to a child of <votable> directly

Your opinions welcome, also considering that DALI-1.1 is in RFC.

Cheers,
    Marco

>
> 2 ) When you want to use Datalink from a protocol response which is not
> SIAV2 or ObsTap: let's say, SCS, SSA, SIAV1, TAP apart Obstap, SLAP or
> whatever, the best way to call it is to add a Datalink descriptor as Carlos
> did in his ASTERICS presentation. The list of IDs used by the DataLink
> service must be in one of main table columns to make this solution work.
>
> Cheers
>
> François
>
>
>
> Le 21/03/2017 à 12:08, Pierre Fernique a écrit :
>
>
> Dear DAL and App contributors,
> and especially SIAv2 and Datalink authors,
>
> In the contexte of the Aladin v10 developments, we are facing to a recurrent
> issue in the IVOA protocol suite.
>
> Most of IVOA protocols return VOTable, but without any signature or magic
> code.
> The consequence: IVOA clients can not easily recognize that this VOTable
> stream comes from a CS, a SIAv1, a SIAv2, a SSA, a Datalink, a TAP, an
> obsTAP or any other IVOA VOTable query result.
>
> Based on the presence of some UCDs or utypes or INFO tags, Aladin tries to
> recognize the original protocol in order to have the adequat actions (basic
> table display, fov supports, popup menus, column display filtering...). But
> we fail to find such a method for SIAv2. We are, more or less able to
> recognize obsCore results (based on utypes list =>
> "obscore:ObsDataset.dataProductType", "obscore:Access.Reference" and
> "obscore:Access.Format" , but it is not specifical to SIAv2.
>
> We are facing to the same difficulty for Datalink results. In this case, it
> is worse in the sense that some providers have already inserted Datalink
> links inside SIAv1 or CS results (see examples below). So in these cases, we
> cannot know "a priori" that such link will return Datalink VOTable stream.
> Without this knowledge, at the end, Aladin can only try to display on the
> sky view the VOTable Datalink result as a regular astronomical catalog (sad
> !).
>
> So, how can we do ? Thanks for any help.
>
> For the future standard releases, may we just think to systematically add
> the standardID of the original protocol inside an INFO tag, or something
> equivalent ?
>
> Pierre Fernique & Chaitra (in charge of SIAv2/Datalink/... implementation in
> Aladin v10)
>
> ---
>
> Datalink examples:
>
> GAVO SIAv1
>
> http://dc.zah.uni-heidelberg.de/lswscans/res/positions/siap/siap.xml?POS=210.8431667,54.2961666667&SIZE=0.1323&FORMAT=image/fits
> => Example of Datalink URL inside the result :
> http://dc.zah.uni-heidelberg.de/lswscans/res/positions/dl/dlmeta?ID=ivo%3A//org.gavo.dc/%7E%3Flswscans/data/part2/Schmidtplatten/FITS/A82.fits
>
> VizieR CS
>
> http://vizier.u-strasbg.fr/viz-bin/votable?-source=B%2Fcfht%2Fobscore&-c=09+55+33.17+%2B69+03+55.1&-out.add=_RAJ,_DEJ&-oc.form=dm&-out.meta=DhuL&-out.max=999999&-c.rm=10.81&-out=_VizieR,*Mime(image/fits),*&-mime=TSV&-out.all
> => Example of Datalink URL inside the result :
> http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/caom2ops/datalink?runid=ejkaxv927qnvu4ef&ID=caom%3ACFHT%2F469601%2F469601o
>
>