An STC "when" and "where" example

[Alasdair Allan]

Arnold Rots wrote:
> What I heard you say is that a VOEvent service should be allowed to 
> provide the amount of detail that it feels like providing, and if that 
> makes it useless to a client, that's too bad for the client and (s)he 
> should just ignore the event.
>
> What I was saying is that that is not acceptable; it does not conform 
> with accepted astronomical practice, as evidenced, for instance, by 
> the requirements for IAU Circulars.

Sorry but that's nuts. What about cases where there isn't enough 
information existing to provide enough detail for all the clients to 
act on? Do we not send an VOEvent message out at all? How do you figure 
out the level of detail required by the clients? You can't, there is an 
unknowable number of clients, many perhaps hidden behind brokering 
services which can't be seen by the process sending the alert, which 
may require different levels of detail to carry out their science 
programme.

This is nothing to do with the IAU accepted practices, and everything 
to do with the way you build the architectures for reliable and robust 
web services. The process sending the alert literally cannot have the 
responsibility to assess the level of accuracy or information required 
client side. It's not possible. It has to collect the information it 
knows about, or is willing to pass on without authenticated access as 
some data may be proprietary and must in that case be restricted to 
authenticated clients only, and push that...

Architecturally what you're asking for is not possible from services 
that have to run without human intervention.

Al.