record_transform — Metaproxy Module that performs record transformations
This filter acts on Z39.50 present requests and Z39.50 search requests, and let all other types of packages and requests pass untouched. Its use is twofold: blocking Z39.50 present/search requests that the backend server does not understand or 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 Z39.50 identifier string.
The <retrieval> element and the content
is described in the
Retrieval Facility section
of the YAZ manual.
From Metaproxy version 1.3.26 and onwards, the backend conversion may
also use USEMARCON.
If USEMARCON is enabled, the backend may include
a usemarcon element with two attributes:
stage1 and stage2 that point to
conversion files as interpreted by USEMARCON. One or both must be given.
Schema is in two parts.. One for the filter itself, and one for the retrieval info.
# Metaproxy XML config file schemas
#
# Copyright (C) Index Data
# See the LICENSE file for details.
namespace mp = "http://indexdata.com/metaproxy"
include "retrievalinfo.rnc"
filter_record_transform =
attribute type { "record_transform" },
attribute id { xsd:NCName }?,
attribute name { xsd:NCName }?,
retrievalinfo
# Schema for YAZ retrieval info and USEMARCON extension
#
# Copyright (C) Index Data
# See the LICENSE file for details.
namespace y = "http://indexdata.com/yaz"
start |= retrievalinfo
marc = element y:marc {
attribute inputformat { xsd:string },
attribute outputformat { xsd:string },
attribute inputcharset { xsd:string },
attribute outputcharset { xsd:string }?,
attribute leaderspec { xsd:string }?
}
xslt = element y:xslt {
attribute stylesheet { xsd:string },
element y:param {
attribute name {xsd:string},
attribute value {xsd:string}
}*
}
usemarcon = element y:usemarcon {
attribute stage1 { xsd:string }?,
attribute stage2 { xsd:string }?
}
retrievalinfo =
element y:retrievalinfo {
attribute version { "1.0" },
element y:retrieval {
attribute syntax { xsd:string },
attribute name { xsd:string }?,
attribute identifier { xsd:string }?,
element y:backend {
attribute syntax { xsd:string },
attribute name { xsd:string }?,
(marc | xslt | usemarcon)*
}?
}+
}
A typical configuration looks like this:
<filter type="record_transform">
<retrievalinfo xmlns="http://indexdata.com/yaz" version="1.0">
<retrieval syntax="xml" name="dc"
identifier="info:srw/schema/1/dc-v1.1">
<backend syntax="usmarc" name="F">
<marc inputformat="marc" outputformat="marcxml"
inputcharset="marc-8"/>
<xslt stylesheet="../xml/xslt/MARC21slim2DC.xsl"/>
</backend>
</retrieval>
<retrieval syntax="opac"/>
<retrieval syntax="xml" name="opac">
<backend syntax="opac" name="F">
<marc inputformat="marc" outputformat="marcxml"
inputcharset="marc-8"/>
</backend>
</retrieval>
<retrieval syntax="usmarc">
<backend syntax="usmarc" name="F">
</backend>
</retrieval>
<retrieval syntax="usmarc" name="C">
<backend syntax="unimarc" name="F">
<usemarcon stage1="/etc/usemarcon/uni2us/uni2us.ini"/>
</backend>
</retrieval>
</retrievalinfo>
</filter>