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
- SSA-v0.1.xsd
- This is a working draft version for current use in the Registry.
an example
The reason for two versions is that there are several issues regarding details of the schema represented in
SSA-wd.xsd that still need to be discussed and worked out. However, there is demand to represent current SSA implementations in the registry ASAP; thus,
SSA-v0.1.xsd represents an interim schema that is to be adopted right away. WG approval of this interim schema will be sought at the Fall 2007 Interop in Cambridge.
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.
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