IVO ids and Data Sets Identifiers

[Tony Linde]

> My only problem is that the usage of the # will forbid the 
> usage of the same identifier as an IVO identifier AND as an 
> UR[IL] directly usable to point to a dataset from an 

Good. It should not be usable as a url. It's sole purpose is as an
identifier of a resource within the registry and it has no meaning other
than that. 

> I feel it's a pity to introduce this incompatiblity -- and 
> moreover I agree fully with Arnold, I cannot understand the 
> necessity of a resource_key. What you need is just a unique 
> identifier, which will be supplied by the Authority.ID . It's 
> not the role of the registry to define this, IMHO.

The registry won't be defining either. Users of a registry will be able to
register an authority id and then define the resource keys under that
authority. The registry will ensure that the resource key chosen is unique
within that authority.

This has been discussed for months now. The telecon yesterday agreed that
the resource identifier WD should be submitted as a Proposed Recommendation
to allow projects to try it out, especially during the Jan demo.

If it turns out that people are only registering one resource under each
authority then we can revisit the situation. Let's get something *done*.

Cheers,
Tony. 

> -----Original Message-----
> From: owner-registry at eso.org [mailto:owner-registry at eso.org] 
> On Behalf Of Francois Ochsenbein
> Sent: 24 September 2003 15:22
> To: registry at ivoa.net
> Subject: Re: IVO ids and Data Sets Identifiers 
> 
> 
> 
> Tony,
> 
> My only problem is that the usage of the # will forbid the 
> usage of the same identifier as an IVO identifier AND as an 
> UR[IL] directly usable to point to a dataset from an 
> electronic article. It therefore 
> means that the 2 things have to be disjoined because it is 
> not possible (in the HTTP sense) to make a distinction between
>    //Authority.ID/(resource_key)#(dataset_1) and
>    //Authority.ID/(resource_key)#(dataset_2)
> 
> I feel it's a pity to introduce this incompatiblity -- and 
> moreover I agree fully with Arnold, I cannot understand the 
> necessity of a resource_key. What you need is just a unique 
> identifier, which will be supplied by the Authority.ID . It's 
> not the role of the registry to define this, IMHO.
> 
> Cheers, francois
> 
> >This is in reply to both Francois and Arnold.
> >
> >An AuthorityID is not a service and so will not have an 
> invocation URL 
> >associated with it. The AuthorityID is simply a way of grouping 
> >resources and allowing a registry to know that when it assigns a 
> >ResourceKey, it is globally unique (since no other registry 
> can assign 
> >a ResourceKey to that AuthorityID).
> >
> >So a service *must* have a ResourceKey as part of its unique 
> >identifier, as well as the AuthorityID.
> >
> >On the issue of the dataset identifier, there is no problem with:
> >  ivo://Authority.ID/(resource_key)#(dataset_identification)
> >since this is not being sent to an http server. It will be 
> interpreted 
> >by some piece of software (which can interpret the ivo:// protocol) 
> >which will understand that everything before the '#' sign is 
> a resource 
> >identifier and everything after it a dataset identifier. The 
> software 
> >will use the resource identifier to look up the service 
> metadata, get 
> >the service invocation method (web service or cgi or 
> whatever) and then 
> >call that service using the dataset identifier (as a 
> parameter to the 
> >web service or as the value part of a cgi '?name=value' pair).
> >
> >The ivo:// protocol is for the use of *VO software* only and 
> not http 
> >servers. They may use the same URI convention but they are 
> completely 
> >separate and different naming conventions.
> >
> >Cheers,
> >Tony.
> >
> >> From: owner-registry at eso.org [mailto:owner-registry at eso.org]
> >> On Behalf Of Francois Ochsenbein
> >> Sent: 23 September 2003 22:34
> >> To: registry at ivoa.net
> >> Subject: IVO ids and Data Sets Identifiers
> >> 
> >> 
> >> If I may intervene on this subject of the IVO identifiers, I
> >> would strongly suggest not to use the hash symbol as a 
> >> delimiter, because it has a special meaning in the HTTP 
> >> protocol: it indicates a marker in the document, and what 
> >> comes after the # symbol is quite generally ignored by the 
> >> HTTP servers.  For instance the output of an HTTP GET to
> >>   http://www.stsci.edu/ftp/science/hdfsouth/warnings.html#NICMOS
> >> is exactly identical to the output of
> >>   http://www.stsci.edu/ftp/science/hdfsouth/warnings.html
> >> (the browser simply scrolls the document to position it at 
> >> the "NICMOS" marker)
> >> 
> >> Therefore in the general scheme of the IVO identification
> >>    ivo://Authority.ID/(resource_key)(dataset/subset_identification)
> >> the # sign could maybe appear in the 3rd part
> >> (dataset/subset_identification) but certainly not a separator 
> >> between the parts 2 and 3 (and moreover not between the parts 
> >> 1 and 2) if it is wished that a resource can be reached using 
> >> the http conventions.
> >> 
> >> In fact, for datasets I would more agree with Guenther's
> >> arguments: one Authority.ID, and what follows it is defined 
> >> under the responsability of the Authority.ID who "publishes" 
> >> the way to access to the data. The dataset can effectively be 
> >> a simple document like
> >>    
> ivo://Authority.ID/Resource-Service/Repository/Intrument/datasetID
> >> 
> >> but could also be something like
> >>    
> >> 
> ivo://Authority.ID/RepositoryQuery?instrument=Intrument&ID=datasetID
> >> 
> >> As long as there is no ambiguity (the Authority.ID may
> >> "delegate" the "naming space" to different missions or 
> >> instruments or whatever) the role of the identifiers is 
> >> fulfilled. The problem with the links from the journals is, 
> >> as pointed out by Bob, the requirement for long-term 
> >> persistence which can only be achieved if any change in the 
> >> curator is 
> >> propagated to the Registry who has to make this mapping 
> between the 
> >> 'permanent' and the 'actual' identifiers (the GLU was not bad 
> >> in this role!) 
> 
> ==============================================================
> ==================
> Francois Ochsenbein       ------       Observatoire 
> Astronomique de Strasbourg
>    11, rue de l'Universite F-67000 STRASBOURG       Phone: 
> +33-(0)390 24 24 29
> Email: francois at astro.u-strasbg.fr   (France)         Fax: 
> +33-(0)390 24 24 32
> ==============================================================
> ==================
>