Resources = services!

[Ray Plante]

Hi Tony,

I've reviewed your document and am working up some feedback.  For now, 
here's some quick follow-on to our discussion.

On Tue, 10 Jun 2003, Tony Linde wrote:
> > > - I think 'Resource' is redundant - everything is a resource.
> > 
> > This is allowed for describing resources that (in the eyes of the
> > registrant/curator) do not fall into one of the specific 
> > classes. 
> 
> I'm still not sure I like the idea of 'anything' being dropped into the
> registry with no idea of what it is (ie, no way of automatically identifying
> its class and type).

I don't think this is an issue for the general framework.  If you as a 
registry builder are uncomfortable, then you can choose not to support it.  
If you as a user don't want to see these records, you can choose not to 
return these types.  Even VO-wide registries can choose not to support 
them.  However, the framework should be more general and allow for 
experimentation and variation that leads to evolution.  Disallowing it at 
the framework level seems an unnecessary restriction. 

> You've lost me - probably because I don't know much about web services.
> Resources should be fully described in the registry - whether or not some of
> this description is duplicated in the WSDL - maybe we can ultimately create
> a tool that generates the WSDL from a registry entry. But many resources
> won't be services and many services won't be web service delivered. So the
> WSDL must be subordinate to the registry metadata.

The Service metadata in VOResource attempts to leverage off existing 
interfaces instead of duplicating them.  The two examples are Web Services 
and GLU services.  Where such descriptions do not exist, the necessary 
description of the interface is defined; the examples of these are 
browser-based services (using the WebBrowser interface element) and HTTP 
Get-based services (using ParamHTTPGet, defined at the moment in 
VOStdService.xsd).  

The alternative is essentially reinventing the wheel in some way.  For Web 
Services, either you reinvent a schema for transmitting the same 
information that WSDL was designed to capture, or you reinvent the 
mechanism for accessing it.  Despite the fact that the WSDL file is 
referenced via a URL, a registry is free to pre-cache that file and index 
its contents, incorporating it into its searchable data.  

cheers,
Ray