Re: [Geotools-devel] Process API update patch, the return

[Jody G. <jod...@gm...>]

Hi Andrea -

Thanks for chasing this one along - some comments inline...

On 29/08/2009, at 5:59 AM, Andrea Aime wrote:
> One significant feedback I got was to use Name instead of a String
> to indentify the processes. I mulled over it a bit but in the end
> it makes a lot of sense, since the quickest way to get lots of
> processes is to bind external providers, that most likely will
> have similarly named processes. For example, I think we have buffering
> in GeoTools, but there is one in Sextante as well, and if we ever
> decide to hook up GRASS abilities as well we'd have a third one.
> So... it's a good idea to namespace them a little.

yep.

> In practice thought, I've looked around and never seen anyone
> use the code space, that is, never seen something like:
>
> <Identifier codeSpace="xxx">buffer</Identifier>
>
> For example 52N WPS will apparently use the fully qualified
> name of the class as the process identifier, lots of
> dots and qualifications, but no codeSpace usage.

I have only run into code spaces with referencing authorities; so  
codespace "EPSG" is maintained by one authority; and codespace "OGC"  
maintained by another...
I assume undertakings like INSPIRE will have a "code" space where they  
will define some mandatory operations that WFS servers need to  
support ... this is however only my assumption!

> Adding to that, the KVP encoding requires the identifier
> to be specified somehow in the mandatory DescribeProcess
> KVP request asks one to use an Identifier in the KVP, but
> there is no guidance on how to encode the codespace,
> and all the examples do use plain jane strings, stuff like:
>
> http://foo.bar/foo?
>       Service=WPS&
>       Request=DescribeProcess&
>       Version=1.0.0&
>       Language=en-CA
>       Identifier=intersection,union

I remember having some trouble with deegree server when they started  
requiring a "namespace" for their "typenames" even when it went  
against WFS=1.0 spec; as I understand it this is a feature of WFS 1.1  
- could we mirror the idea?
>
> Following the patch in GeoServer I've basically ignored
> the codeSpace and made a convention that ":" is used
> to separate the namespace from the local name, so for
> example the GeoTools buffer process will be named
>
> <Identifier>gt:buffer</Identifier>

yeah okay that works for me.

> and a KVP request will say &Identifier=gt:buffer...
> Hacky but works and it's consistent between
> XML and KVP encodings... anyone with a better idea?

Nope I am content; breaking out a codespace KVP would not be  
consistent; however this is something to feedback to  
sta...@os... as a question.

> Long story short, using namespaced identiferies is a
> good idea, but it does not seem to apply in a straightforward
> way to the WPS protocol as is today.
>
> Can anyone review? I would like to commit and finally bind some  
> Sextante processes to GeoServer.

I will be happy to review.

Jody