X-Git-Url: http://git.indexdata.com/?p=idzebra-moved-to-github.git;a=blobdiff_plain;f=doc%2Frecordmodel-alvisxslt.xml;h=c633022cae14edd6c4b1ec81959c4c68d4403eaa;hp=764190da266a33d214b29a7414a86ba896fd767a;hb=693a0db94b4b3ac9aee7722572a6b81a86a12e13;hpb=14a2dbce03d7802ab5b1e57b09d915339bb5fc54 diff --git a/doc/recordmodel-alvisxslt.xml b/doc/recordmodel-alvisxslt.xml index 764190d..c633022 100644 --- a/doc/recordmodel-alvisxslt.xml +++ b/doc/recordmodel-alvisxslt.xml @@ -1,126 +1,457 @@ - - - ALVIS XML Record Model and Filter Module - + + ALVIS &acro.xml; Record Model and Filter Module + + + + The functionality of this record model has been improved and + replaced by the DOM &acro.xml; record model, see + . The Alvis &acro.xml; record + model is considered obsolete, and will eventually be removed + from future releases of the &zebra; software. + + The record model described in this chapter applies to the fundamental, - structured XML + structured &acro.xml; record type alvis, introduced in - . The ALVIS XML record model - is experimental, and it's inner workings might change in future - releases of the Zebra Information Server. + . - - + This filter has been developed under the + ALVIS project funded by + the European Community under the "Information Society Technologies" + Program (2002-2006). + - - ALLVIS Record Filter +
+ ALVIS Record Filter - The experimental, loadable Alvis XM/XSLT filter module + The experimental, loadable Alvis &acro.xml;/&acro.xslt; filter module mod-alvis.so is packaged in the GNU/Debian package libidzebra1.4-mod-alvis. + It is invoked by the zebra.cfg configuration statement + + recordtype.xml: alvis.db/filter_alvis_conf.xml + + In this example on all data files with suffix + *.xml, where the + Alvis &acro.xslt; filter configuration file is found in the + path db/filter_alvis_conf.xml. + + The Alvis &acro.xslt; filter configuration file must be + valid &acro.xml;. It might look like this (This example is + used for indexing and display of &acro.oai; harvested records): + + <?xml version="1.0" encoding="UTF-8"?> + <schemaInfo> + <schema name="identity" stylesheet="xsl/identity.xsl" /> + <schema name="index" identifier="http://indexdata.dk/zebra/xslt/1" + stylesheet="xsl/oai2index.xsl" /> + <schema name="dc" stylesheet="xsl/oai2dc.xsl" /> + <!-- use split level 2 when indexing whole OAI Record lists --> + <split level="2"/> + </schemaInfo> + + + + All named stylesheets defined inside + schema element tags + are for presentation after search, including + the indexing stylesheet (which is a great debugging help). The + names defined in the name attributes must be + unique, these are the literal schema or + element set names used in + &acro.srw;, + &acro.sru; and + &acro.z3950; protocol queries. + The paths in the stylesheet attributes + are relative to zebras working directory, or absolute to file + system root. + + + The <split level="2"/> decides where the + &acro.xml; Reader shall split the + collections of records into individual records, which then are + loaded into &acro.dom;, and have the indexing &acro.xslt; stylesheet applied. + + + There must be exactly one indexing &acro.xslt; stylesheet, which is + defined by the magic attribute + identifier="http://indexdata.dk/zebra/xslt/1". - - ALLVIS Internal Record Representation - FIXME - - - - ALLVIS Canonical Format - FIXME - - - - - - - - ALLVIS Record Model Configuration - FIXME - - - - +
+ ALVIS Internal Record Representation + When indexing, an &acro.xml; Reader is invoked to split the input + files into suitable record &acro.xml; pieces. Each record piece is then + transformed to an &acro.xml; &acro.dom; structure, which is essentially the + record model. Only &acro.xslt; transformations can be applied during + index, search and retrieval. Consequently, output formats are + restricted to whatever &acro.xslt; can deliver from the record &acro.xml; + structure, be it other &acro.xml; formats, HTML, or plain text. In case + you have libxslt1 running with E&acro.xslt; support, + you can use this functionality inside the Alvis + filter configuration &acro.xslt; stylesheets. + +
+ +
+ ALVIS Canonical Indexing Format + The output of the indexing &acro.xslt; stylesheets must contain + certain elements in the magic + xmlns:z="http://indexdata.dk/zebra/xslt/1" + namespace. The output of the &acro.xslt; indexing transformation is then + parsed using &acro.dom; methods, and the contained instructions are + performed on the magic elements and their + subtrees. + + + For example, the output of the command + + xsltproc xsl/oai2index.xsl one-record.xml + + might look like this: + + <?xml version="1.0" encoding="UTF-8"?> + <z:record xmlns:z="http://indexdata.dk/zebra/xslt/1" + z:id="oai:JTRS:CP-3290---Volume-I" + z:rank="47896"> + <z:index name="oai_identifier" type="0"> + oai:JTRS:CP-3290---Volume-I</z:index> + <z:index name="oai_datestamp" type="0">2004-07-09</z:index> + <z:index name="oai_setspec" type="0">jtrs</z:index> + <z:index name="dc_all" type="w"> + <z:index name="dc_title" type="w">Proceedings of the 4th + International Conference and Exhibition: + World Congress on Superconductivity - Volume I</z:index> + <z:index name="dc_creator" type="w">Kumar Krishen and *Calvin + Burnham, Editors</z:index> + </z:index> + </z:record> + + + This means the following: From the original &acro.xml; file + one-record.xml (or from the &acro.xml; record &acro.dom; of the + same form coming from a split input file), the indexing + stylesheet produces an indexing &acro.xml; record, which is defined by + the record element in the magic namespace + xmlns:z="http://indexdata.dk/zebra/xslt/1". + &zebra; uses the content of + z:id="oai:JTRS:CP-3290---Volume-I" as internal + record ID, and - in case static ranking is set - the content of + z:rank="47896" as static rank. Following the + discussion in + we see that this records is internally ordered + lexicographically according to the value of the string + oai:JTRS:CP-3290---Volume-I47896. + + + In this example, the following literal indexes are constructed: + + oai_identifier + oai_datestamp + oai_setspec + dc_all + dc_title + dc_creator + + where the indexing type is defined in the + type attribute + (any value from the standard configuration + file default.idx will do). Finally, any + text() node content recursively contained + inside the index will be filtered through the + appropriate char map for character normalization, and will be + inserted in the index. + + + Specific to this example, we see that the single word + oai:JTRS:CP-3290---Volume-I will be literal, + byte for byte without any form of character normalization, + inserted into the index named oai:identifier, + the text + Kumar Krishen and *Calvin Burnham, Editors + will be inserted using the w character + normalization defined in default.idx into + the index dc:creator (that is, after character + normalization the index will keep the individual words + kumar, krishen, + and, calvin, + burnham, and editors), and + finally both the texts + Proceedings of the 4th International Conference and Exhibition: + World Congress on Superconductivity - Volume I + and + Kumar Krishen and *Calvin Burnham, Editors + will be inserted into the index dc:all using + the same character normalization map w. + + + Finally, this example configuration can be queried using &acro.pqf; + queries, either transported by &acro.z3950;, (here using a yaz-client) + + open localhost:9999 + Z> elem dc + Z> form xml + Z> + Z> f @attr 1=dc_creator Kumar + Z> scan @attr 1=dc_creator adam + Z> + Z> f @attr 1=dc_title @attr 4=2 "proceeding congress superconductivity" + Z> scan @attr 1=dc_title abc + ]]> + + or the proprietary + extensions x-pquery and + x-pScanClause to + &acro.sru;, and &acro.srw; + + + + See for more information on &acro.sru;/&acro.srw; + configuration, and or the &yaz; + &acro.cql; section + for the details or the &yaz; frontend server. + + + Notice that there are no *.abs, + *.est, *.map, or other &acro.grs1; + filter configuration files involves in this process, and that the + literal index names are used during search and retrieval. + +
+
+ + +
+ ALVIS Record Model Configuration + + +
+ ALVIS Indexing Configuration + + As mentioned above, there can be only one indexing + stylesheet, and configuration of the indexing process is a synonym + of writing an &acro.xslt; stylesheet which produces &acro.xml; output containing the + magic elements discussed in + . + Obviously, there are million of different ways to accomplish this + task, and some comments and code snippets are in order to lead + our Padawan's on the right track to the good side of the force. + + + Stylesheets can be written in the pull or + the push style: pull + means that the output &acro.xml; structure is taken as starting point of + the internal structure of the &acro.xslt; stylesheet, and portions of + the input &acro.xml; are pulled out and inserted + into the right spots of the output &acro.xml; structure. On the other + side, push &acro.xslt; stylesheets are recursively + calling their template definitions, a process which is commanded + by the input &acro.xml; structure, and are triggered to produce some output &acro.xml; + whenever some special conditions in the input stylesheets are + met. The pull type is well-suited for input + &acro.xml; with strong and well-defined structure and semantics, like the + following &acro.oai; indexing example, whereas the + push type might be the only possible way to + sort out deeply recursive input &acro.xml; formats. + + + A pull stylesheet example used to index + &acro.oai; harvested records could use some of the following template + definitions: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ]]> + + + + Notice also, + that the names and types of the indexes can be defined in the + indexing &acro.xslt; stylesheet dynamically according to + content in the original &acro.xml; records, which has + opportunities for great power and wizardry as well as grande + disaster. + + + The following excerpt of a push stylesheet + might + be a good idea according to your strict control of the &acro.xml; + input format (due to rigorous checking against well-defined and + tight RelaxNG or &acro.xml; Schema's, for example): + + + + + + + ]]> + + This template creates indexes which have the name of the working + node of any input &acro.xml; file, and assigns a '1' to the index. + The example query + find @attr 1=xyz 1 + finds all files which contain at least one + xyz &acro.xml; element. In case you can not control + which element names the input files contain, you might ask for + disaster and bad karma using this technique. + + + One variation over the theme dynamically created + indexes will definitely be unwise: + + + + + + + + + + + + + + + + + + ]]> + + Don't be tempted to cross + the line to the dark side of the force, Padawan; this leads + to suffering and pain, and universal + disintegration of your project schedule. + +
+ +
ALVIS Exchange Formats - FIXME - - - + + An exchange format can be anything which can be the outcome of an + &acro.xslt; transformation, as far as the stylesheet is registered in + the main Alvis &acro.xslt; filter configuration file, see + . + In principle anything that can be expressed in &acro.xml;, HTML, and + TEXT can be the output of a schema or + element set directive during search, as long as + the information comes from the + original input record &acro.xml; &acro.dom; tree + (and not the transformed and indexed &acro.xml;!!). + + + In addition, internal administrative information from the &zebra; + indexer can be accessed during record retrieval. The following + example is a summary of the possibilities: + + + + + + + + + + + + + + + + + + + + + + + ]]> + + + +
+ +
+ ALVIS Filter &acro.oai; Indexing Example + + The source code tarball contains a working Alvis filter example in + the directory examples/alvis-oai/, which + should get you started. + + + More example data can be harvested from any &acro.oai; compliant server, + see details at the &acro.oai; + + http://www.openarchives.org/ web site, and the community + links at + + http://www.openarchives.org/community/index.html. + There is a tutorial + found at + + http://www.oaforum.org/tutorial/. + +
+ +
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