[occi-wg] JSON Rendering

Jamie Marshall ijm667 at hotmail.com
Wed Apr 18 04:41:35 EDT 2012


Both are good for me.Jamie

> To: ijm667 at hotmail.com
> Subject: RE: [occi-wg] JSON Rendering
> Date: Wed, 18 Apr 2012 09:19:55 +0200
> From: ralf at nyren.net
> CC: florian.feldhaus at gwdg.de; occi-wg at ogf.org
> 
> 
> What about:
> 
>  - Monday 2012-04-23 at 16:00 CET (14:00 UTC)
> 
> or
> 
>  - Tuesday 2012-04-24 at 16:00 CET (14:00 UTC)
> 
> ?
> 
> 
> 
> regards, Ralf
> 
> 
> 
> On Tue, 17 Apr 2012 22:15:05 +0200, Jamie Marshall <ijm667 at hotmail.com>
> 
> wrote:
> 
> > Monday, Tuesday and Friday, at any time, are my best days, Wednesday is
> 
> > quite busy and Thursday is out of the question.SincerelyJamie
> 
> > 
> 
> > 
> 
> > From: florian.feldhaus at gwdg.de
> 
> > To: ralf at nyren.net
> 
> > Date: Tue, 17 Apr 2012 19:59:07 +0000
> 
> > CC: occi-wg at ogf.org
> 
> > Subject: Re: [occi-wg] JSON Rendering
> 
> > 
> 
> > I would also like to participate. What date / time would be best for
> 
> you?
> 
> > For me every day of the week would work.
> 
> >  
> 
> > --Florian
> 
> >  
> 
> > Am 17.04.2012 um 21:34 schrieb Ralf Nyren:
> 
> >  
> 
> >> Good idea, next week should be ok.
> 
> >> /Ralf
> 
> >> 
> 
> >> On Tue, 17 Apr 2012 17:51:04 +0200, Edmonds, AndrewX
> 
> >> <andrewx.edmonds at intel.com> wrote:
> 
> >> 
> 
> >>> Suggestion: are people free for a confcall say next week to review and
> 
> >>> finalise the JSON work needed to be completed?
> 
> >>> 
> 
> >>> Andy
> 
> >>> 
> 
> >>> -----Original Message-----
> 
> >>> From: occi-wg-bounces at ogf.org [mailto:occi-wg-bounces at ogf.org] On
> 
> >>> Behalf Of alexander.papaspyrou at tu-dortmund.de
> 
> >>> Sent: Thursday, April 05, 2012 3:46 PM
> 
> >>> To: ralf at nyren.net
> 
> >>> Cc: occi-wg at ogf.org
> 
> >>> Subject: Re: [occi-wg] JSON Rendering
> 
> >>> 
> 
> >>> +1 from me on the separation path. Let's get it proper before it
> 
> cannot
> 
> >>> be separated anymore.
> 
> >>> 
> 
> >>> -A.
> 
> >>> 
> 
> >>> Am 05.04.2012 um 16:43 schrieb "Ralf Nyren" <ralf at nyren.net>:
> 
> >>> 
> 
> >>>> 
> 
> >>>> On Thu, 5 Apr 2012 09:21:52 +0000, "Feldhaus, Florian"
> 
> >>>> <florian.feldhaus at gwdg.de> wrote:
> 
> >>>>> Hi,
> 
> >>>>> 
> 
> >>>>> how do we proceed?
> 
> >>>> 
> 
> >>>> The best thing IMO would be to create a version 1.2 of the HTTP
> 
> >>>> Rendering doc and update it so that it is a clear separation between
> 
> >>>> Protocol and Data Format. The existing text/occi, text/occi and the
> 
> >>>> JSON data formats would then be pluggable modules to this spec.
> 
> >>>> 
> 
> >>>> The quick way is to continue writing the JSON rendering as a
> 
> >>>> standalone HTTP-based OCCI rendering which happens to be quite
> 
> similar
> 
> >>>> to the HTTP Rendering. Saves time but causes lots of duplication.
> 
> >>>> 
> 
> >>>>> Following a some responses to your comments:
> 
> >>>>> 
> 
> >>>>> Am 04.04.2012 um 10:59 schrieb Ralf Nyren:
> 
> >>>>> 
> 
> >>>>>> On Tue, 03 Apr 2012 14:31:24 +0200, Feldhaus, Florian
> 
> >>>>>> <florian.feldhaus at gwdg.de> wrote:
> 
> >>>>>> 
> 
> >>>>>>> Hi,
> 
> >>>>>>> 
> 
> >>>>>>> once again I would like to reiterate the JSON rendering. First a
> 
> >>>>>>> short overview what Alexander and I think are the main points we
> 
> >>>>>>> should
> 
> >>>>>>> address:
> 
> >>>>>>> - remove all HTTP Rendering specific parts from the JSON rendering
> 
> >>>>>> 
> 
> >>>>>> Remember that an OCCI rendering (as currently specified) includes
> 
> >>>> _both_
> 
> >>>>>> protocol and data format at the moment.
> 
> >>>>> 
> 
> >>>>> That's only partly true. A "pure" JSON rendering can already exist
> 
> >>>>> independently from the HTTP Rendering without any trouble in
> 
> >>>>> rendering.
> 
> >>>> 
> 
> >>>> No. Yes.
> 
> >>>> 
> 
> >>>> Probably a misunderstanding here. An OCCI Rendering is defined as a
> 
> >>>> way to manipulate the Core Model. So in theory you could have 2
> 
> >>>> different HTTP-based OCCI Renderings with different semantics where
> 
> >>>> one happen to be using XML as the data format and the othe JSON for
> 
> >>>> example. This is not nice but within the definition.
> 
> >>>> 
> 
> >>>> So to be complete an OCCI Rendering must both define the protocol and
> 
> >>>> whatever data format is used by that protocol.
> 
> >>>> 
> 
> >>>> This does not prevent us from having a single OCCI HTTP Protocol
> 
> >>>> Rendering with pluggable data formats.
> 
> >>>> 
> 
> >>>>>> I like the idea of having a common HTTP Protocol rendering spec
> 
> >>>>>> which the JSON rendering could be built upon though.
> 
> >>>>> 
> 
> >>>>> I second this and would like to move forward. Any comments on the
> 
> >>>>> best strategy? Do we need to create a version 1.2 for the HTTP
> 
> >>>>> rendering?
> 
> >>>> 
> 
> >>>> I believe so yes. It would be mostly backwards compatible though.
> 
> >>>> 
> 
> >>>>>> However, the current HTTP rendering doc lacks things like e.g.
> 
> >>>>>> request parameters in URL which I would say is necessary to have a
> 
> >>>>>> sane JSON rendering.
> 
> >>>>> 
> 
> >>>>> I don't think so. The rendering should be independently of the
> 
> >>>>> transport protocol. If I ask your server to send me a file by mail
> 
> >>>>> containing the JSON rendering of all resources, that should work as
> 
> >>>>> well.
> 
> >>>> 
> 
> >>>> We are probably using different terminology here. I am referring to
> 
> an
> 
> >>>> OCCI "rendering". Your statement is 100% true for an OCCI data
> 
> format.
> 
> >>>> However, a data format is not enough to create an OCCI Rendering.
> 
> >>>> 
> 
> >>>>>>> - consider using RFC 5988 "Web Linking" for collection information
> 
> >>>>>>> (e.g. index, next, previous,…)
> 
> >>>>>> 
> 
> >>>>>> Gary and I had an email conversation which resulted in a solution
> 
> >>>>>> where all info necessary for pagination would end up in the request
> 
> >>>>>> URL. I.e.
> 
> >>>>>> basically eliminating the need for using special headers (such as
> 
> >>>>>> RFC 5988).
> 
> >>>>>> 
> 
> >>>>>> The request parameters to a collection simply allow you to specify
> 
> >>>>>> the amount of resource instances you want returned either _before_
> 
> >>>>>> or
> 
> >>>> _after_
> 
> >>>>>> a specific occi.core.id.
> 
> >>>>> 
> 
> >>>>> Do you have some examples? IMHO this should go to the revised HTTP
> 
> >>>>> rendering document.
> 
> >>>> 
> 
> >>>> The mail thread was on occi-wg so should be in the archives.
> 
> >>>> 
> 
> >>>> Agree that it would be best to put this into a 1.2 version of the
> 
> HTTP
> 
> >>>> Rendering doc.
> 
> >>>> 
> 
> >>>>>>> Examples:
> 
> >>>>>>> http://pastebin.com/ZK9Uf0K1 (Entities)
> 
> >>>>>> 
> 
> >>>>>> Nice, I like that you keep the "attributes" hash now ;)
> 
> >>>>>> 
> 
> >>>>>> How do you render Link attributes for the links tied to an OCCI
> 
> >>>> Resource?
> 
> >>>>> 
> 
> >>>>> In the example you can see Links are rendered as a hash containing
> 
> >>>>> href and kind. The only really necessary part is the href location.
> 
> >>>> Everything
> 
> >>>>> else is optional and could be retrieved by the client using separate
> 
> >>>> HTTP
> 
> >>>>> requests. It would also be possible to omit the hash and just render
> 
> >>>>> all link hrefs in an array. To allow for a slim rendering and also
> 
> >>>>> allow for additional information to be send to the client, I would
> 
> >>>>> suggest that we specify a hash with at least the href and optional
> 
> >>>>> all other parameters valid for the link. We could even go so far as
> 
> >>>>> to use the link rendering for rendering link attributes within
> 
> >>>>> resources.
> 
> >>>> 
> 
> >>>> After many long discussions it was decided to have inline rendering
> 
> of
> 
> >>>> Link attributes in the OCCI HTTP Rendering. I think the same should
> 
> >>>> apply to JSON.
> 
> >>>> 
> 
> >>>>>>> To keep the mail short, a detailed discussion can be found in the
> 
> >>>>>>> attached text document.
> 
> >>>>>> 
> 
> >>>>>> Just picking out one thread:
> 
> >>>>>> 
> 
> >>>>>>> resources and links should be represented differently. The entry
> 
> >>>>>>> "links" is unique for resources and the entries "target" and
> 
> >>>>>>> "source"
> 
> >>>>>>> are unique for links.
> 
> >>>>>> 
> 
> >>>>>> Sounds goods. So the top-level hash of the collection format would
> 
> >>>>>> have one hash "resources" and another hash "links" then?
> 
> >>>>>> I mean, we still have to cover the case where the client asks for
> 
> >>>>>> "everything" at the top-level URL and thus gets both Resources and
> 
> >>>> Links
> 
> >>>>>> in the response.
> 
> >>>>> 
> 
> >>>>> I would suggest to have a content-type for entities. It should
> 
> >>>>> contain a hash with "links" and "resources". Both then are arrays of
> 
> >>>>> hashes.
> 
> >>>> 
> 
> >>>> I rather have a single array, it plays much better with the
> 
> collection
> 
> >>>> concept of REST.
> 
> >>>> 
> 
> >>>>>>> In OCCI Core the attribute names should be changed from
> 
> >>>>>>> occi.core.source and occi.core.target to just source and target,
> 
> as
> 
> >>>> both
> 
> >>>>>>> are representing connections to other resources from within the
> 
> >>>>>>> OCCI model (similar to links in resources, or kind in entity).
> 
> >>>>>> 
> 
> >>>>>> occi.core.source and occi.core.target was named simply
> 
> source/target
> 
> >>>>>> up until just before the OCCI HTTP Rendering doc was published.
> 
> >>>>>> 
> 
> >>>>>> The fundamental problem here is that we have two different sorts of
> 
> >>>>>> "attributes".
> 
> >>>>>> 1. Attributes as part of the OCCI Core model. These include both
> 
> >>>>>> Entity.id, Entity.title, Resource.summary, Resource.links,
> 
> >>>>>> Link.target, Link.source, etc 2. Attributes as exposed by an OCCI
> 
> >>>>>> rendering. The HTTP Rendering exposes id, title, summary as
> 
> >>>>>> attributes as well as target and source.
> 
> >>>>>> However the Resource.links attribute is not exposed as an
> 
> >>>>>> attribute...
> 
> >>>>>> 
> 
> >>>>>> There is no clear distinction here which IMO leads to confusion.
> 
> >>>> 
> 
> >>>> No comments on the above?
> 
> >>>> 
> 
> >>>>>> Also remember that a subclass of OCCI Link may have Link.target
> 
> >>>> pointing
> 
> >>>>>> at some arbitrary external object.
> 
> >>>>> 
> 
> >>>>> In my opinion, source and target always point to resources, even if
> 
> >>>>> they lie outside the OCCI model. They contain complex data types
> 
> like
> 
> >>>>> kind or mixin and not primitive data types like id, title or
> 
> summary.
> 
> >>>> 
> 
> >>>> So, to link to a VNC console you would have the vnc:// URL where? In
> 
> a
> 
> >>>> VNC console Resource object?
> 
> >>>> 
> 
> >>>> /Ralf
> 
> >>>> _______________________________________________
> 
> >>>> occi-wg mailing list
> 
> >>>> occi-wg at ogf.org
> 
> >>>> https://www.ogf.org/mailman/listinfo/occi-wg
> 
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> 
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> 
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> 
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> 
> >>> 
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> >  
> 
> > 
> 
> > _______________________________________________
> 
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> 
> > occi-wg at ogf.org
> 
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