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Re: Relationship to OASIS standards

From: Yves Lafon <ylafon@w3.org>
Date: Thu, 16 Apr 2009 13:24:33 -0400 (EDT)
To: Johannes Echterhoff <johannes.echterhoff@igsi.eu>
cc: public-ws-resource-access@w3.org
Message-ID: <Pine.LNX.4.64.0904090506520.3559@ubzre.j3.bet>
On Mon, 6 Apr 2009, Johannes Echterhoff wrote:

Dear Johannes,

> I am new to this list, therefore I am going to quickly introduce myself: my
> name is Johannes Echterhoff and I am involved in standardization activities
> of the Open Geospatial Consortium (OGC - http://www.opengeospatial.org).
>
> Recently, there was quite a discussion in an OGC working group on how to
> create standards that support both REST(ful) and WS-* (based upon standards
> from W3C and OASIS) style web services. A lot of these discussions revolve
> around the resources we need to model and how to do that in both
> architectural styles. For the WS-* style, this brought me to the WS-Resource
> specifications from OASIS. In addition, we want to integrate
> publish/subscribe functionality in some of our web services. This brought me
> to WS-Notification. I favoured the OASIS specifications because they reached
> the final specification status, while for example WS-Eventing at the time
> was "only" a W3C submission.

First, the "WS-* style" is not really dictated by all the WS-* 
specifications, but mostly by tools, then by selected clusters of 
WS-* specification. It is entirely possible to create RESTful Web Services 
using SOAP 1.2 and WSDL, (although a bit difficult to find the tools for 
that), but some WS-* specs are indeed mandating partially the overall 
architecture.

> Now that I learnt of the activities of your working group, I have some
> questions that I hope you can answer:
>
> How are the activities of this W3C working group, especially the resulting
> documents / standards related to the work done by OASIS? For example,
> WS-Eventing appears to provide a subset of the functionality given by
> WS-Notification.

There are no relationship between WS-Eventing work within the WS-RA WG and 
OASIS, unless OASIS TCs want to send issues, in that case they will be 
considered like all other issues by the Working Group, and if alignment is 
possible, there is nothing preventing it.

> Some time ago I read about a common approach to eventing in web service
> environments, titled WS-EventNotification. I thought this was a great idea,
> having a basic set of functionality which would support basic pub/sub and
> optional extensions which provided higher functionality, like topic based
> subscriptions or brokering. Unfortunately, according to
> http://travisspencer.com/blog/2008/11/effort-to-converge-ws-eventing.html
> the efforts to harmonize WS-Eventing and WS-Notification and create a
> single, common standard have ceased. Please comment if this is true and if
> so why the common approach has been abandoned.

As those efforts were made outside W3C framework, only participants in 
that effort are able to comment and explain why it didn't happen.

> There seems to be functional overlap of WS-(Resource)Transfer with the
> WS-ResourceProperties specification from OASIS. The current working drafts
> from your group look like they are more compatible with the http interface
> (get, put, delete etc.), so the functionality implemented by the proposed
> operations look like they could be more easily ported to a REST(ful) style
> web service - is this the intention?

WS-Transfer is quite close to the basic definition of verbs used in HTTP, 
WS-ResourceTransfer is one of the possible concrete use of WS-Transfer, 
and yes, being closer to HTTP while allowing the same kind of 
architectural style running on other underlying transports might indeed 
help keeping the same architectural style between both implementations.

> [As for WS-MetadataExchange and WS-Enumeration I do not know of an OASIS
> equivalent (have heard about WS-MetadataExchange before and found it quite
> useful), but if there is one, please let me know.]
>
>
> For my work at the OGC, I need guidance which approach (that from W3C or
> OASIS) to use and promote. It would help a lot if there was a public
> statement to what extent these apparently competing standards differ or
> share the same functionality. If possible, guidance why one should use one
> approach over the other would be highly appreciated - something like best
> practices for various use cases. Right now the only arguments pro/contra an
> approach for me are its current specification status
> (submission/recommendation/draft/etc.), the functionality required/provided
> and the available toolbase.

Issue is that things that appear to be competing quite often are not. I 
wold take the example of WS-Choreography and BPEL, they seem to tackle the 
same issue, but in fact they do it form different angles and are not 
really competing (especially as WS-Choreography didn't reach final REC).
So the right approach is first to settle on the functionnality you want to 
provide and pick the set on specification you want to adhere to based on 
that.

> The thing is that for my OGC related standardization work I need to decide
> which WS-* standards to use and which not to use. I would not like to end up
> with a W3C and an OASIS architectural style for the implementation
> specification of my geospatial web service, in addition to the REST(ful)
> style.

There is no "W3C and OASIS architectural styles", both organizations 
produced specifications that should help you implement Web Services using 
your architectural style. What matters most is your use cases and what you 
want to achieve.

> You see that I am a bit confused with the (apparently emerging) functional
> overlap of W3C and OASIS specifications. I hope you can help to clarify the
> current situation (on managing resources and eventing/notification in web
> services).

Could you come up with a set of issues based on differences between your 
requirements and the specifications the WS-RA WG is producing? That would 
be the ideal way to understand the issue you have with eventing and 
notification.
Cheers,

-- 
Baroula que barouleras, au tiƩu toujou t'entourneras.

         ~~Yves
Received on Thursday, 16 April 2009 17:24:42 GMT

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