WS-Transfer and HTTP, re TAG Issues whenToUseGet-7 & endPointRefs-47

A recent submission [1] to W3C, WS-Transfer [2], is a specification  
for a
protocol that provides document retrieval and management — the same
service provided by HTTP.  We infer that WS-Transfer is intended for
situations where:

* HTTP functionality is required but over some
   message-passing system which does not support TCP

* There is a requirement for Web Services
   capabilities, but no API is available to
   access the HTTP protocol layer

* There is a requirement for some Web Service
   capability that HTTP does not provide

The design of WS-Transfer raises a number of issues, several of which  
are
mentioned in the W3C's staff comment on the submission [3].  These  
issues
include:

* Does WS-Transfer's use of Web Services Addressing
   End Point References (EPRs) instead of URIs
   damage the Web?

* When WS-Transfer is carried over HTTP, can it make
   proper use of HTTP as an application level-protocol?
   Should a default HTTP binding be specified to promote
   proper use of the WS-Transfer/SOAP/HTTP combination?

Some of these concerns  were also discussed on the TAG's  
teleconference of

10 October 2006 [4].  We note that the TAG has for some time been  
tracking

at least two issues that are pertinent to WS-Transfer:

TAG issue whenToUseGet-7 [5] was originally raised in connection with  
XML
Forms, but was also the umbrella under which GET support was integrated
into the SOAP Recommendation [6,7,8] and into its HTTP binding [9].   
Those

changes provide means by which SOAP can properly use HTTP, and also  
allow
for SOAP envelopes to be directly sourced from conventional Web servers
[10] such as Apache.  The TAG also issued a related finding "URIs,
Addressability, and the use of HTTP GET and POST" [11].   The TAG has
reopened issue whenToUseGet-7, in part to facilitate discussion of
WS-Transfer.

Another issue pertinent to WS-Transfer is issue endPointRefs-47 [12],
under which the TAG has discussed several concerns relating to EPRs, and
their relationship to URIs.  In October of 2005, the TAG requested [13]
changes to the Web Services Addressing draft Recommendations, to  
indicate
the great value of using URIs, and only URIs, as the means of  
identifying
resources.

In accepting the member submission of WS-Transfer, the W3C team
observed[3]:

"The W3C Team plans to notify the Web Services Coordination Group of  
this
Member Submission but has no plans to start a Working Group in this  
area.
The Team also plans to ask the Technical Architecture Group (TAG) to
investigate the impact of this technology on the architecture of the  
Web."

Accordingly, this note is to announce that the TAG will indeed be
considering WS-Transfer, and to invite discussion on the www-tag@w3.org
mailing list.

Tim Berners-Lee
For the W3C Technical Architecture Group

  [1] http://www.w3.org/Submission/2006/04/

  [2] http://www.w3.org/Submission/WS-Transfer/

  [3] http://www.w3.org/Submission/2006/04/Comment

  [4]
http://lists.w3.org/Archives/Public/www-tag/2006Oct/att-0053/10- 
tagmem-minutes.html


  [5] http://www.w3.org/2001/tag/issues.html?type=1#whenToUseGet-7

  [6] http://www.w3.org/TR/soap12-part2/#WebMethodFeature

  [7] http://www.w3.org/TR/soap12-part2/#RPCResourceRetrieval

  [8] http://www.w3.org/TR/soap12-part2/#soapresmep

  [9] http://www.w3.org/TR/soap12-part2/#soapinhttp

[10] http://www.w3.org/TR/soap12-part2/#httpinterop

[11] http://www.w3.org/2001/tag/doc/whenToUseGet-20030922.html

[12] http://www.w3.org/2001/tag/issues.html?type=1#endPointRefs-47

[13] http://lists.w3.org/Archives/Public/www-tag/2005Oct/0057.html

ENDS

Received on Tuesday, 24 October 2006 17:24:15 UTC