Definitive version of the VOTable schema for web services

[Doug Tody]

Hi -

This discussion may be academic as we may not want to modify "legacy"
code such as SkyNode etc., but it may still be worthwhile to help
determine why we have this problem and how to avoid it if we mix
VOTable and WSDL in the future.

The easiest way for a client app to deal with something as complex as
a VOTable is using VOTable class code.  The VOTable is passed through
the interface as a string or file, and accessed via the class code.
There is no need to bind it in a SOAP interface, except possibly to
a string parameter.

Of course a beginner (or wizard) might want to just use a tool such
as wsdl2java.  So the real question is, are WSDL and SOAP capable of
passing through a large complex string containing an encoded object?
In other words, is the problem with the SkyNode etc. interface and
WSDL, with the VOTable schema, or both?

This stuff really is broken if it tries to parse and validate very
complex schemas for external objects - that is a matter for the object
class code, not the interface, to deal with.

We still might want to simplify the VOTable schema, but the reason to
do that would be to simplify the schema and avoid unnecessary problems,
not to fix broken SOAP code.  It would be good to understand better
how these two issues sort out.

	- Doug


On Tue, 29 Jul 2008, Matthew Graham wrote:

> Hi,
> 
> I agree entirely with you, Doug. There, however, a number of services such as
> OpenSkyQuery,  SkyNodes, CasJobs, WESIX, etc. which give VOTable in response.
> The easiest way to use these for complete beginners is to use wsdl2java or
> wsdl2py and then just employ the client stubs. It takes a certain amount of
> experience and knowledge to bypass these tools and deal with VOTable directly
> in client calls with SOAP.
> 
> 	Cheers,
> 
> 	Matthew
> 
> 
> On Jul 29, 2008, at 7:51 PM, Doug Tody wrote:
> 
> > Hi -
> > 
> > I sympathize with the folks who don't much care about automatically
> > code-binding a VOTable, as this makes little sense for such a complex
> > object, however we have little need for a recursive constructs in
> > a table mechanism.  Simplifying the schema would have little effect
> > on any existing, heavily used code but could simplify these SOAP use
> > cases so might be worthwhile in any case.  On the other hand, why are
> > we referencing something as large and complex as the VOTable schema
> > at all in a SOAP call? (the same question would apply to something
> > like STC).  There ought to be a way to pass-through the VOTable as a
> > string without need to reference the schema.  The schema should only be
> > used for simple function arguments can be bound to language datatypes.
> > 
> > 	- Doug
> > 
> > 
> > On Tue, 29 Jul 2008, Matthew Graham wrote:
> > 
> > > Hi,
> > > 
> > > I really think that this has to come from the VOTable WG, even if it is
> > > now
> > > officially dormant. We have complained about this enough for long enough
> > > that
> > > it is shocking that we do not have a solution. Hopefully, one of the other
> > > national projects is sitting on a version of VOTable that actually works
> > > with
> > > all the code binders so it's minimal effort.
> > > 
> > > 	Cheers,
> > > 
> > > 	Matthew
> > > 
> > > On Jul 29, 2008, at 6:44 PM, Roy Williams wrote:
> > > 
> > > > If only there were some really smart person who understands XML schema
> > > > and
> > > > WSDL and all that -- who would be kind enough to volunteer to help the
> > > > IVOA
> > > > by proposing a universal VOTable schema.
> > > > Roy
> > > > 
> > > > 
> > > > Matthew Graham wrote:
> > > > > Hi,
> > > > > 
> > > > > Yes, I know it has and it's normally this time of year that I make the
> > > > > same request. It would be nice if we could actually sort this out once
> > > > > and
> > > > > for all.
> > > > > 
> > > > > Cheers,
> > > > > 
> > > > > Matthew
> > > > > 
> > > > > On Jul 29, 2008, at 6:02 PM, Alberto Conti wrote:
> > > > > 
> > > > > > I hope you will have more success that I had pointing this out.
> > > > > > It has been this way since a long long time ago....
> > > > > > -A
> > > > > > 
> > > > > > On Jul 29, 2008, at 8:18 PM, Matthew Graham wrote:
> > > > > > 
> > > > > > > Hi,
> > > > > > > 
> > > > > > > The VOTable schema that exists on the IVOA web site cannot just be
> > > > > > > imported into a WSDL document. There are several web services,
> > > > > > > e.g.
> > > > > > > Open SkyQuery, SkyNode, WESIX, which have produced their own
> > > > > > > version
> > > > > > > of the schema to work with WSDL - essentially all the complexTypes
> > > > > > > need to be named and globally defined instead of being anonymous
> > > > > > > under
> > > > > > > the elements. I was wondering whether the VOTable group could
> > > > > > > produce
> > > > > > > a sanctioned version of the VOTable 1.1 schema that will work with
> > > > > > > WSDL?
> > > > > > > 
> > > > > > > Cheers,
> > > > > > > 
> > > > > > > Matthew
> > > > > > 
> > > > > > Dr Alberto Conti
> > > > > > Community Missions Office
> > > > > > Space Telescope Science Institute
> > > > > > contact | tel: 410-338-4534 | aim: wscience
> > > > > > 
> > > > > > 
> > > > > 
> > > > 
> > > > -- 
> > > > 
> > > > California Institute of Technology
> > > > 626 395 3670
> > > > 
> > > 
> > 
>