Re: [cmis] Rendition AtomPub and domain model inconsistency

[Florent Guillaume <fg@nuxeo.com>]

2010/2/9 Al Brown <albertcbrown@us.ibm.com>:
> So I can better understand, what is the use case in atompub where the client has a streamid?
> Why is the uri not sufficient to  differentiate the resources?

Sometimes you don't get a URI, there is none in the <rendition> element.

> The only use case I see is an api layer that supports both ws and atompub and uses the streamid above.  In that scenario why wouldn't the layer surface the uri as streamid above?

When a client uses a renditionFilter to get a set of possible
renditions (through <rendition> elements), and then chooses the
rendition he's interested in based on attributes like the mime type,
width, kind, etc. Then his only unique handle to get the actual
rendition content stream is the streamId.

Florent


> From: Florent Guillaume [fg@nuxeo.com]
> Sent: 02/09/2010 03:37 PM CET
> To: cmis <cmis@lists.oasis-open.org>
> Subject: [cmis] Rendition AtomPub and domain model inconsistency
>
>
>
> CMIS-630 was deferred from previous meetings. David C suggested we
> resolve it via
> email discussion, so here it is. For convenience, in the JIRA issue I wrote:
>
> There is a slight inconsistency between the domain model and the
> AtomPub way of exposing renditions.
> In the domain model a rendition has a unique id and a non-unique kind.
> This is exposed through <cmis:rendition>.
> But in the AtomPub rel=alternate links only cmisra:renditionKind is exposed.
> So, given a just rendition id, if there are several renditions of the
> same kind, an AtomPub client has no way of choosing which rendition
> link to use.
>
> To fix this, we can add a cmisra:streamId attribute to the atom:link
> element, but this would require a spec change so I'd think it's
> logical to defer this to 2.0.
>
> In the meantime unofficially I would advise server vendors to use
> rendition links of the form http://...?streamId=foo which would help
> clients introspect these URIs and choose the correct one.
>
> What do you think?
>
> Florent

-- 
Florent Guillaume, Director of R&D, Nuxeo
Open Source, Java EE based, Enterprise Content Management (ECM)
http://www.nuxeo.com   http://www.nuxeo.org   +33 1 40 33 79 87