Definitive version of the VOTable schema for web services

[Matthew Graham]

Hi,

OK, let's look at it this way: you have written a web service that  
returns a VOTable. The WSDL document will describe your service and  
specify the syntax of the request and response messages. Obviously  
what you would like to say (in a machine-readable format) is that the  
response message contains a VOTable. The style of web service that we  
advocate (doc/lit wrapped) means that we define the datatypes that are  
used in the messages in terms of XML Schema contained in the WSDL.

It is the inadequacies of the SOAP code that do not understand VOTable  
that force you to think about describing your service as returning XML  
or a string instead. And the WSDL then becomes a poor man's  
description because there then has to be some other piece of  
description that tells me as a client that this XML or string that I  
am getting from your service is really a VOTable. What is that other  
description? Is it machine readable? How do I find it? etc.

VOTable is a transport format that does not play very well with the  
tools that are supposed to use it.

	Cheers,

	Matthew

On Jul 29, 2008, at 9:34 PM, Doug Tody wrote:

> Hi Matthew -
>
> Thanks, that is what I needed to know.
>
> I think the SOAP code should be treating the VOTable as either
> your case 1 or 2 (string or XML-formatted string), but not as 3
> (VOTable with schema).  Aside from asking for trouble from such
> a complex schema, and having redundant object verification, it
> is inefficient to carry schema validation this far.  The VOTable
> should be passed through either as a string or as an XML formatted
> string, probably the former, with the client using real class code
> (a VOTable library) to deal with it.  Aside from reducing complexity
> and improving efficiency, if I were writing an application I would
> prefer to discover object-related errors when I deal with the object,
> not at the level of the low level interface.
>
> It is not clear to me that this means a client can't use a toolkit -
> if the WSDL treats a complex document as a string one could probably
> still use a toolkit or framework.