illegal/unrecommended use of IVOA identifiers

[John Taylor]

Hi Ray,
First up, apologies for the delay in replying to this. 
There is A Reason behind the choice of ivoids as messages.  They're 
meant to be unique, so using a URI seems to be reasonable.  Why a 
registry URI?  Well, we think that there could be a benefit in 
registering the messages as separate resources.  Messages are unique and 
there aren't that many of them, so why not register them?  That way the 
URI can be dereferenced to provide a (hopefully) unambiguous definition 
of what the message means, and who is responsible for its definition.  
It also opens up other possibilities: the user wants to find an 
application that can accept a VOTable, a search of the registry reveals 
the ivo://..../loadVOTable message VOResource, a follow up search then 
locates the applications that understand the message (assuming we've got 
as far as registering desktop applications).  All this would be hidden 
away behind some clever helper app of course.   Another possibility is 
you could have some Plastic message sender tool that could interrogate 
the registry to construct the GUI for any message.

Now if we decide not to the register the messages, it doesn't impact on 
the registry at all...the messages are just rather odd opaque 
strings....so where's the harm?

I do plan to register Plastic as a standard as you suggest - and will 
probably be bugging you on how to do this.  BTW - we can't use URI 
fragments as you propose, since they have another meaning in Plastic.

John

PS - the choice of votech.org as an authority Id was a mistake (well, 
let's be fair - it was my mistake)...I shouldn't have polluted the 
votech.org authId.


Ray Plante wrote:
> Hi John et al.
>
> I don't know if this has been pointed out to you or not; however, the 
> Plastic Specification is using IVOA identifiers in a non-standard way 
> to identify its messages.
>
> The IVOA Identifiers specification
> (http://www.ivoa.net/Documents/latest/IDs.html) states that the use of 
> the ivo indicates that the identifier has been registered with an IVOA 
> registry (section 3.2.2).
>
> To be compliant, each of the Plastic message identifiers would have to 
> be registered as a separate resource.  While in principle this is 
> possible, this is highly discouraged.  Instead, I would recommend the 
> approach that is to be used by the VOSpace standard in which names are 
> identified using a # suffix; e.g.,
>
>    ivo://votech.org/plastic#info/getIVORN
>
> For use of an identifier of this form to be compliant, only the 
> ivo://votech.org/plastic resource need be registered.  We have a new 
> schema we are putting forward for this purpose called VOStandard 
> (http://www.ivoa.net/internal/IVOA/RegUpgradeSummer2006/VOStandard-v0.1.xsd). 
>
> It defines two new Resource sub-classes, Standard and StandardService,
> that registers the existance of a standard; the former is probably 
> most appropriate for Plastic.  These types do not currently provide 
> metadata for defining what I might call properties (e.g. 
> info/getIVORN); however, we should probably add that.  Note that the 
> standard being described need not be an IVOA standard.
>
> Please let me know if you have any comment or suggestions on this front.
> The Registry WG is the WG that handles the Identifier standard.
>
> cheers,
> Ray
>
>
>


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