[occi-wg] Format 4: Angle bracket or curly brackets

[Sam Johnston]

Alexis,

All of these points actually work in favour of XML - comments inline:

On Wed, May 13, 2009 at 4:50 PM, Alexis Richardson <
alexis.richardson at gmail.com> wrote:

> My 2c on this one:
>
> * I worry that allowing users to extend the core on the wire protocol
> by having something as extensible as XML, will lead them to do so in
> ways that break interop


I think we all [need to] accept that users must be able to extend the
protocol and in order to do so safely XML offers namespaces (among other
things) - in fact we need to do the same ourselves unless we're expecting to
deliver everything (billing, SLAs, monitoring, etc.) at the same time in one
bundle. Most alternatives (including JSON) put everyone in a room together
and still expect to be able to work out who farted when things go wrong.


> * I want something where it is really totally bogglingly obvious when
> the data deviates from the allowed format
>

Tightly specified XML is trivial to burn into any one of a number of schema
formats (e.g. RELAX NG) and then you've got on- and off-line validators
which can tell you exactly which line was broken and why. This is marvellous
for debugging and was used extensively to beat the reference implementation
into compliance with Atom 1.0, without having to rely on talking to another
implementation which may or may not be right. Most alternatives (including
JSON) have no such functionality... at least not yet.


> I note that eg HTTP has a very narrow core for interop, but people
> have come up with lots of ways to extend its usefulness by convention
> eg AtomPub
>

You realise of course that this works because HTTP adds a small amount of
structure to an arbitrary/opaque data channel? Atom does the same, just
adding the bare minimum of XML structure in the process...

Sam


> On Wed, May 13, 2009 at 3:42 PM, Richard Davies
> <richard.davies at elastichosts.com> wrote:
> > Decision 4: For the core wire format(s), is XML or JSON the better syntax
> > ('angle brackets vs. curly brackets')
> > a) XML
> > b) JSON
> >
> > Important*: This is an independent decision from decision 3 on meta-model
> >
> > Perspective of myself and Alexis: No strong view. We lean towards JSON,
> > since it feels easier to make a tight specification and hence to easier
> to
> > guarantee interoperability. Tightly specified use of XML might be equally
> > good.
> > _______________________________________________
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> > occi-wg at ogf.org
> > http://www.ogf.org/mailman/listinfo/occi-wg
> >
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