Describing SSA services as a VO resource
Part of the standardization of a protocol is defining an XML schema for describing an instance of the service, primarily in a VO registry. This is done by creating an extension of the
VOResource schema.
Working Draft Schemas
Two working draft versions are currently available.
- SSA-wd.xsd: This is the version for Working Group discussion.
an example Note - this version is under final internal review; barring further comments, it will be released as an external working draft schema.
- SSA-v0.1.xsd
- This is a working draft version for current use in the Registry.
an example
Barring any further comments, the top schema will become SSA-v0.2.xsd and supercede the top one.
Representing v1.0 and pre-1.0 implementations
One important issue we need to address is how to support the earliest
SSA implementations. These were built well before v1.0 of the SSA
spec was completed; thus, it is unlikely that they would be compliant
at this time. Still, several do exist, and it would be good to
recognize these as serving spectra.
The subsection below gives a proposal for representing the pre-v1.0 services with a special version value on the interface. However, the editor of the SSA spec voiced a preference for labelling pre-v1.0 implementations using a different capability
xsi:type
, and there were no dissents. Thus, in the new schema above, there is a second capability type (defined identically to the first one) called
"ProtoSpectralAccess"
(as oppsed to
"SimpleSpectralAccess"
).
Previous version proposal
VOResource v1.0 allows one to list in one resource description support
for different versions of a protocol. For SSA, this means that within
the "SimpleSpectralAccess" capability element, multiple interface
elements may be listed, each with a different value for its version
attribute. (If version is not provided, "1.0" is to be assumed.)
I recommend that we encourage the registration of the early SSA services using the "SimpleSpectralAccess" capability but to set the value of the interface element to "proto". That is,
<ri:Resource ...>
...
<capability xsi:type="ssa:SimpleSpectralAccess">
<interface xsi:type="vs:ParamHTTP" version="proto">
<accessURL> ... </accessURL>
</interface>
...
<capability>
...
</ri:Resource>
(If you don't "proto" as a version string, please suggest an
alternative, e.g "0.5".)
--
RayPlante - 24 Sep 2007