record_transform — Metaproxy Module that performs Z39.50 presentResponse record transformations
This filter acts only on Z3950 present requests, and let all other types of packages and requests pass untouched. It's use is twofold: blocking Z3950 present requests, which the backend server does not understand and can not honor, and transforming the present syntax and elementset name according to the rules specified, to fetch only existing record formats, and transform them on the fly to requested record syntaxes.
The allowed record present syntax and
element name are described in multiple
<retrieval>
elements inside the
<retrievalinfo>
element. The syntax
attribute is mandatory, but
the name
attribute
may be omitted, in which case any
element name is accepted. An additional
identifier
attribute can be added to explicitly
describe the Z3950 identifier string.
Record transformations are invoked when the optional attributes
backendsyntax
and backendname
as well as the <convert>
element are specified.
Record conversions come in two flavors:
<marc>
binary conversions between different
binary MARC formats and MarcXML formats, and
<xslt>
stylesheet transformations performed
on any kind of XML records. These conversions can be stacked in any
order, and are performed linearly in file order.
The binary MARC record transformations
<marc>
are defined using the following
attributes: inputformat
, outputformat
,
inputcharset
and outputcharset
.
XML <xslt>
transformation instructions
accept only one mandatory stylesheet
attribute,
which is either an absolute path, or a relative path from the
working directory of metaproxy
to the location
of the requested XSLT stylesheet.
A typical configuration looks like this:
<filter type="record_transform"> <retrievalinfo> <retrieval syntax="grs-1"/> <retrieval syntax="usmarc" name="F"/> <retrieval syntax="usmarc" name="B"/> <retrieval syntax="xml" name="marcxml" identifier="info:srw/schema/1/marcxml-v1.1" backendsyntax="usmarc" backendname="F"> <convert> <marc inputformat="marc" outputformat="marcxml" inputcharset="marc-8"/> </convert> </retrieval> <retrieval syntax="xml" name="danmarc" backendsyntax="usmarc" backendname="F"> <convert> <marc inputformat="marc" outputformat="marcxchange" inputcharset="marc-8"/> </convert> </retrieval> <retrieval syntax="xml" name="dc" identifier="info:srw/schema/1/dc-v1.1" backendsyntax="usmarc" backendname="F"> <convert> <marc inputformat="marc" outputformat="marcxml" inputcharset="marc-8"/> <xslt stylesheet="xml/xslt/MARC21slim2DC.xsl"/> </convert> </retrieval> </retrievalinfo> </filter>