[OAI-implementers] on the extensibility of OAI-PMH

[Fabio Simeoni]

Hi,

a 3rd party would like to consider extensions of the oai:recordType
component of the protocol's schema in order to disclose per-record
information other than and in addition to descriptive metadata (say
contained in a <foo> element following the <metadata> element). The extra
information is optional, in that standard OAI requests simply do not trigger
its generation; accordingly, the party would very much like this kind of
extension to be backword-compatible, so that a single implementation of the
extended server would equally serve old and new clients of the protocol.
Conceptually such an extension *is* backword-compatible but the protocol's
schema does not cater for it (why?). The 3rd party must either extend within
the OAI namespace, which it does not own (apparently a bad practice even
when technically harmless) or else extend into a new namespace and accept to
break all namespace-aware old clients. Is this correct and, in case, is
there a way around it? Or must the 3rd party admit that standard and
extended implementations of the protol must live (and be maintained) side by
side at two different URLs? 

regards,

fabio

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Fabio Simeoni 
Research Fellow
Department of Computer & Information Sciences
University of Strathclyde, Glasgow

TEL: +44 141 548 (3590)
FAX: +44 141 548 (4523)