how to make a publisherDID

[Patrick Dowler]

I need to decide on a procedure for making publisherDID values for use in TAP 
services, for example in the ivoa.ObsCore table, but also our internal CAOM 
tables which also expose the same identifiers. This is following from the 
interesting DAL-DM-DCP discussions on use of URIs.

Presumably, I could start with a DataCollection identifier registered in the 
IVOA registry system, eg:

ivo://cadc.nrc.ca/archive/cfht

(note: more generally, a creatorDID would be linked to a DataCollection and a 
publisherDID might be linked to a provider/service in case they are not the 
same or definitive provider - let's ignore that for now)

In the past we would use the fragment, eg 
ivo://cadc.nrc.ca/archive/cfht#12345/raw but that implies that one can somehow 
"get" the entire collection and then look for "12345/raw" inside it (client 
side). 

Instead, I could append some dataset-specific to get an observation identifier, 
eg.

ivo://cadc.nrc.ca/archive/cfht/12345

and then append something product-specific to get an identifier for the product, 
eg.

ivo://cadc.nrc.ca/archive/cfht/12345/raw

However, if someone has one of these (the last one), what can they do with it? 
With this approach, there is no prescribed way to extract the identifier for 
the registered DataCollection. Should there be?

In VOSpace, the spec invents a new URI scheme (vos) that prescribes exactly 
how to extract/create the service URI from the vos URI, but it comes down to 
being able to separate the URI into two halves: a base that can be looked up 
in a registry and a separate bit (path in vos) that can be used when talking 
to the service. In principle this does not require a new scheme, but it does 
require at least a way to separate.

PS-I have the exact same issue with several services where I want to identify 
the service with an ivo URI and I want to make and use URIs for items found 
within/via that service.

-- 

Patrick Dowler
Tel/Tél: (250) 363-0044
Canadian Astronomy Data Centre
National Research Council Canada
5071 West Saanich Road
Victoria, BC V9E 2M7

Centre canadien de donnees astronomiques
Conseil national de recherches Canada
5071, chemin West Saanich
Victoria (C.-B.) V9E 2M7