[OAI-implementers] OAI-PMH & SOAP

Van de Sompel, Herbert Herbert.VandeSompel@bl.uk
Sat, 2 Feb 2002 19:49:12 -0000


Following some recent mentioning of SOAP on oai-implementers, we felt it
would be informative to list some major reasons why the upcoming v.2.0 of
the OAI-PMH will not -- yet -- have a SOAP version: 

* At the occasion of the first public presentation of the OAI-PMH 1.0 (DC,
Jan 2001) it was announced that the protocol would be kept unchanged for a
period of approx 12-18 months in order to allow for thorough
experimentation.  Also, it was announced that a stabilized version of the
protocol, taking into account the feedback of implementers, would be
released at the end of that 18-month period.  In order not to demotivate
early implementers, a "promise" was made by the OAI that the stabilized
version would be kept as close to version 1.0/1.1 as possible.  Since
v.1.0/1.1 is a protocol layered on top of HTTP, it was felt strongly that
v.2.0 should -- at least -- also have a version that remained on that chosen

* When starting the revision the OAI-PMH v.1.1., the OAI-tech group listed
approx. 20 issues for discussion.  One was the creation of a SOAP version of
the protocol (in addition to the HTTP-layered track).  Following the
procedure followed by oai-tech for this protocol revision, a white paper was
created by a member, which was brought forward for discussion.  Not a single
reaction was posted to the white paper, which presumably indicated the lack
of strong interest among the OAI-tech group and the communities it

Next, again, following the OAI-tech procedure, the OAI Executive posted a
mail to OAI-tech suggesting to drop the SOAP path for version 2.0 of the
OAI-PMH.  The following motivations were given:

- No perceived demand (until very recently, there had been no postings re
SOAP on the oai-implementers list, which was created Jan 2001);

- SOAP-related activities may draw energy away from the ongoing efforts for
the stabilization of the current -- non-SOAP -- version of the protocol (at
this point in time we are 100% sure that it would have been impossible to
meet the 05/2002 deadline for the release of OAI-PMH 2.0 if we had decided
to create a SOAP version too);

- No overwhelming indication of the existence of SOAP champions in the
OAI-tech team, willing to lead an effort with this respect. 

In the same mail, the OAI-Executive suggested to finalize version 2.0 first,
and then take on a SOAP version of the protocol.  

This posting by the OAI-Exec resulted in 3 supportive mails from OAI-tech
members, and no opposition.  Later on, in a conference call where all issues
where brought up again, OAI-tech decided unanimously to focus efforts on
stabilization of the non-SOAP version of the protocol, meanwhile encouraging
experimentation with and exploration of the SOAP path, in order to get ready
for the release of a SOAP version somewhere down the line.

* Indirect feedback received from a group working on a SOAP-based "Z39.50
New Generation" protocol suggested that they were running into certain
issues caused by the lack of stability of SOAP.  

* v.2.0 of the protocol will be much more disentagled from HTTP than
v.1.0/1.1.  As a result, a move to a SOAP version seems to be a logical next

Carl Lagoze & Herbert Van de Sompel
OAI Executive

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