TAP RFC [VOSI]

[Patrick Dowler]

Just to clarify: 

I take it that with this compromise resources and service ops 
(getCapabilities) would both be required in TAP 1.0, with a very simple 
explanation that they return the same document. Thus, the sync endpoint would 
retain the DAL RPC style interface and the users of either endpoint could use 
the resources or the RPC mechanism in 1.0.

It would open up the possibility in future to make one or both of async and 
sync optional. Just looking ahead to that a bit, it seems one would likely do 
it as follows:

- async is optional
- if async is supported, async must have sibling resources for metadata
- sync is optional
- if sync is supported, sync must support service ops

It appears we could make such a change without making any TAP 1.0 services 
invalid. Thus, we have two usage patterns that mesh together and we just have 
to make it clear that these few things that look like the same thing really 
are and they return the same metadata documents.

We retain the REQUEST and VERSION (it was retained in the proposed change, 
maybe that was not clear) as an avenue for future evolution or as a way for 
services to do custom operations.

Does that capture the essence of the proposed compromise? Does anyone see any 
issues or dead-ends for later versions? 

Pat

PS-I don't know that we will ever want to make sync/async optional... but I 
will comment in response to Alberto's question in a separate message.


On Sunday 27 September 2009 10:11:22 Douglas Tody wrote:
>      1)  We add resource endpoints for the VOSI operations.  Hence for base
>          resources we have the following (all with the same baseURL):
> 
>              sync
>              async
>              capabilities
>              availability
>              tableMetadata
> 
>      2)  We retain REQUEST and VERSION to specify the logical (service
>          specific) service operations.  These use either the sync or
>          async endpoints.  Hence we have
> 
>              async/REQUEST=doQuery&VERSION=1.0&...       # TAP
>              sync/REQUEST=queryData&VERSION=1.0&...      # Other DAL
>                  (etc.)
> 
>      3)  We require that getCapabilities be provided as a service
>          operation as well as as a base resource:
> 
>              sync/REQUEST=getCapabilities
> 

-- 

Patrick Dowler
Tel/Tél: (250) 363-0044
Canadian Astronomy Data Centre
National Research Council Canada
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