RE: [oslc-core] Resource Preview Proposal

From
Sarabura, Martin <>
Date
2015-07-29T16:08:10+00:00
ID
Thread
RE: [oslc-core] Resource Preview Proposal
Martin, I think it's OK to use "deprecated". Since we're moving the standard over to OASIS it's in our best interest to make the transition as easy as possible.
 Hence full backwards compatibility makes sense now and for the foreseeable future, but maybe some day when tooling is sufficiently robust and everybody has upgraded to v3+ we can talk about truly deprecating a feature that is currently only marked as such.
 In the meantime clients can be developed against the non-deprecated specification, lessening the overall reliance on those features.

 

I am about to open up the ballot. Only members with voting privileges can vote on the ballot though all members will be able to see the results. If I've set
 it up properly each question on the ballot will allow for a comment - including for example on what it really means to "prefer" a representation. The system does allow amendments to be added to the text but most likely we'll just set up a new ballot if we
 needed. I can declare the ballot passed or rejected once we have quorum one way or the other.

 

 

Martin Sarabura

R&D Fellow, PTC

 

 

 

 

 

From:  [mailto:]
On Behalf Of Martin P Pain

Sent: July-29-15 11:45 AM

To: Jim Amsden

Cc: OASIS

Subject: Re: [oslc-core] Resource Preview Proposal

 

In general I'm happy to go this way, but I do (as always) have some more thoughts. Apologies if I'm just nit-picking.

"deprecated":

What does it mean in this context to mark things as "deprecated" if we've said that we never want to break backwards compatibility? It seems to mean something that we would remove if we could but
 we've said we're not going to. 

1. Preview discovery:

a. Can I suggest that we change the rel from "...#Compact" to be "...#compact" (lower-case "c"). It seems wrong to use something that looks like a class name as a rel value. Following the convention
 for triple predicates of a lower-case initial seems more fitting. 

b. Saying "servers MUST honour" a Prefer header seems to go against the meaning of "Prefer" (e.g. vs "Expect" - although I don't know much about that header and I'm not suggesting we use it). Does
 LDP require servers to honour any prefer headers that it specifies?

Martin Pain

Software Developer - Green Hat

Rational Test Virtualization Server, Rational Test Control Panel

 

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From:        "Jim Amsden" <>

To:        OASIS <>

Date:        29/07/2015 14:55

Subject:        Re: [oslc-core] Resource Preview Proposal

Sent by:        <>

After reviewing all the issues and options, which are discussed in detail in
https://wiki.oasis-open.org/oslc-core/V2Compatibility#preview,
 I'd like to make the following simple proposal for Resource Preview:

1. Preview Discovery

To preserve compatibility with OSLC2, preview discovery must continue to support the Accept: application/x-oslc-compact+xml header to get the Compact resource. This usage will be noted as deprecated. OLSC3 clients should use the Link header with rel="http://open-services.net/ns/core#Compact"
 and the Prefer header with include="http://open-services.net/ns/core#PreferCompact”, using the Accept header with standard MIME types such as text/turtle, application/rdf+xml, application/ld+json,
 etc. to get the Compact resource in the desired format.

2. Preview Resource Representation 

OSLC3 must continue to support the OSLC2 Compact resource XML representation. This format will be noted as deprecated. OSLC3 clients should use the Accept and Prefer headers to get the compact resource in Turtle or JSON format. Servers may support other formats
 such as application/rdf+xml and application/ld+json.

3. Preview Resize

OSLC3 will continue to support the OSLC2 oslc-preview-height resize message, but this usage will be noted as deprecated. OSLC3 servers should use the oslc-resize message. OSLC3 servers should send both the oslc-preview-height and oslc-resize messages if OSLC2
 compatibility is a requirement.

This results in very few changes to Resource Preview - just including the x- MIME type and XML format for the OSLC2 Compact resource, and handling the oslc-preview-height resize message for OSLC2 compatibility.

In order to complete the edits as soon as possible, we can try an electronic vote on this proposal.

Jim Amsden, Senior Technical Staff Member

OSLC and Linked Lifecycle Data

919-525-6575

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