<?xml version="1.0" standalone="no"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1//EN"
- "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd"
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
+ "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd"
[
- <!ENTITY local SYSTEM "local.ent">
+ <!ENTITY copyright SYSTEM "copyright.xml">
+ <!ENTITY % local SYSTEM "local.ent">
+ %local;
<!ENTITY manref SYSTEM "manref.xml">
- <!ENTITY progref SYSTEM "progref.xml">
- <!ENTITY % common SYSTEM "common/common.ent">
- %common;
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- -->
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]>
-<!-- $Id: book.xml,v 1.47 2007-01-08 12:27:27 marc Exp $ -->
-<book id="metaproxy">
+<book>
<bookinfo>
<title>Metaproxy - User's Guide and Reference</title>
- <author>
- <firstname>Adam</firstname><surname>Dickmeiss</surname>
- </author>
- <author>
- <firstname>Marc</firstname><surname>Cromme</surname>
- </author>
- <author>
- <firstname>Mike</firstname><surname>Taylor</surname>
- </author>
+ <authorgroup>
+ <author>
+ <firstname>Adam</firstname><surname>Dickmeiss</surname>
+ </author>
+ <author>
+ <firstname>Marc</firstname><surname>Cromme</surname>
+ </author>
+ <author>
+ <firstname>Mike</firstname><surname>Taylor</surname>
+ </author>
+ </authorgroup>
+ <releaseinfo>&version;</releaseinfo>
<copyright>
- <year>2005-2007</year>
- <holder>Index Data ApS</holder>
+ <year>2005-2015</year>
+ <holder>Index Data</holder>
</copyright>
<abstract>
<simpara>
+ This manual is part of Metaproxy version &version;.
+ </simpara>
+ <simpara>
Metaproxy is a universal router, proxy and encapsulated
metasearcher for information retrieval protocols. It accepts,
processes, interprets and redirects requests from IR clients using
- standard protocols such as
+ standard protocols such as the binary
<ulink url="&url.z39.50;">ANSI/NISO Z39.50</ulink>
- (and in the future <ulink url="&url.sru;">SRU</ulink>
- and <ulink url="&url.srw;">SRW</ulink>), as
- well as functioning as a limited
- <ulink url="&url.http;">HTTP</ulink> server.
+ and the information search and retrieval
+ web service <ulink url="&url.sru;">SRU</ulink>
+ as well as functioning as a limited
+ <ulink url="&url.http;">HTTP</ulink> server.
+ </simpara>
+ <simpara>
Metaproxy is configured by an XML file which
specifies how the software should function in terms of routes that
the request packets can take through the proxy, each step on a
using the filter API.
</simpara>
<simpara>
- Metaproxy is <emphasis>not</emphasis> open-source software, but
- may be freely downloaded, unpacked, inspected, built and run for
- evaluation purposes. Deployment requires a separate, commercial,
- license.
+ Metaproxy is covered by the GNU General Public License version 2.
</simpara>
<simpara>
<inlinemediaobject>
<chapter id="introduction">
<title>Introduction</title>
-
-
+
<para>
<ulink url="&url.metaproxy;">Metaproxy</ulink>
is a stand alone program that acts as a universal router, proxy and
encapsulated metasearcher for information retrieval protocols such
- as <ulink url="&url.z39.50;">Z39.50</ulink>, and in the future
- <ulink url="&url.sru;">SRU</ulink> and <ulink url="&url.srw;">SRW</ulink>.
+ as <ulink url="&url.z39.50;">Z39.50</ulink> and
+ <ulink url="&url.sru;">SRU</ulink>.
To clients, it acts as a server of these protocols: it can be searched,
- records can be retrieved from it, etc.
+ records can be retrieved from it, etc.
To servers, it acts as a client: it searches in them,
retrieves records from them, etc. it satisfies its clients'
requests by transforming them, multiplexing them, forwarding them
</para>
</chapter>
- <chapter id="license">
- <title>The Metaproxy License</title>
- <orderedlist numeration="arabic">
- <listitem>
- <para>
- You are allowed to download this software for evaluation purposes.
- You can unpack it, build it, run it, see how it works and how it fits
- your needs, all at zero cost.
- </para>
- </listitem>
- <listitem>
- <para>
- You may NOT deploy the software. For the purposes of this license,
- deployment means running it for any purpose other than evaluation,
- whether or not you or anyone else makes a profit from doing so. If
- you wish to deploy the software, you must first contact Index Data and
- arrange to purchase a DEPLOYMENT LICENCE. If you are unsure
- whether or not your proposed use of the software constitutes
- deployment, email us at <literal>info@indexdata.com</literal>
- for clarification.
- </para>
- </listitem>
- <listitem>
- <para>
- You may modify your copy of the software (fix bugs, add features)
- if you need to. We encourage you to send your changes back to us for
- integration into the master copy, but you are not obliged to do so. You
- may NOT pass your changes on to any other party.
- </para>
- </listitem>
- <listitem>
- <para>
- There is NO WARRANTY for this software, to the extent permitted by
- applicable law. We provide the software ``as is'' without warranty of
- any kind, either expressed or implied, including, but not limited to, the
- implied warranties of MERCHANTABILITY and FITNESS FOR A
- PARTICULAR PURPOSE. The entire risk as to the quality and
- performance of the software is with you. Should the software prove
- defective, you assume the cost of all necessary servicing, repair or
- correction. In no event unless required by applicable law will we be
- liable to you for damages, arising out of the use of the software,
- including but not limited to loss of data or data being rendered
- inaccurate.
- </para>
- </listitem>
- <listitem>
- <para>
- All rights to the software are reserved by Index Data except where
- this license explicitly says otherwise.
- </para>
- </listitem>
- </orderedlist>
- </chapter>
-
<chapter id="installation">
<title>Installation</title>
<para>
</varlistentry>
<varlistentry><term><ulink url="&url.libxslt;">Libxslt</ulink></term>
<listitem>
- <para>This is an XSLT processor - based on
+ <para>This is an XSLT processor - based on
<ulink url="&url.libxml2;">Libxml2</ulink>. Both Libxml2 and
Libxslt must be installed with the development components
(header files, etc.) as well as the run-time libraries.
<listitem>
<para>
The popular C++ library. Initial versions of Metaproxy
- was built with 1.33.0. Version 1.33.1 works too.
+ was built with 1.32 but this is no longer supported.
+ Metaproxy is known to work with Boost version 1.33 through 1.55.
</para>
</listitem>
</varlistentry>
</para>
<para>
We have successfully built Metaproxy using the compilers
- <ulink url="&url.gcc;">GCC</ulink> version 4.0 and
- <ulink url="&url.vstudio;">Microsoft Visual Studio</ulink> 2003/2005.
+ <ulink url="&url.gcc;">GCC</ulink> and
+ <ulink url="&url.vstudio;">Microsoft Visual Studio</ulink>.
</para>
+ <para>
+ As an option, Metaproxy may also be compiled with
+ <ulink url="&url.usemarcon;">USEMARCON</ulink> support which allows for
+ MARC conversions for the <xref linkend="ref-record_transform"/> filter.
+ </para>
<section id="installation.unix">
<title>Installation on Unix (from Source)</title>
<para>
tools binary packages. If, for example, Libxml2/libxslt are already
installed as development packages use those (and omit compilation).
</para>
-
- <para>
- Libxml2/libxslt:
- </para>
- <screen>
- gunzip -c libxml2-version.tar.gz|tar xf -
- cd libxml2-version
- ./configure
- make
- su
- make install
- </screen>
- <screen>
- gunzip -c libxslt-version.tar.gz|tar xf -
- cd libxslt-version
- ./configure
- make
- su
- make install
- </screen>
- <para>
- YAZ/YAZ++:
- </para>
- <screen>
- gunzip -c yaz-version.tar.gz|tar xf -
- cd yaz-version
- ./configure
- make
- su
- make install
- </screen>
- <screen>
- gunzip -c yazpp-version.tar.gz|tar xf -
- cd yazpp-version
- ./configure
- make
- su
- make install
- </screen>
- <para>
- Boost:
- </para>
- <screen>
- gunzip -c boost-version.tar.gz|tar xf -
- cd boost-version
- ./configure
- make
- su
- make install
- </screen>
- <para>
- Metaproxy:
- </para>
- <screen>
- gunzip -c metaproxy-version.tar.gz|tar xf -
- cd metaproxy-version
- ./configure
- make
- su
- make install
- </screen>
+
+ <note>
+ <para>
+ <ulink url="&url.usemarcon;">USEMARCON</ulink> is not available
+ as a package at the moment, so Metaproxy must be built from source
+ if that is to be used.
+ </para>
+ </note>
+
+ <section id="libxml2.fromsource">
+ <title>Libxml2/libxslt</title>
+ <para>
+ Libxml2/libxslt:
+ </para>
+ <screen>
+ gunzip -c libxml2-version.tar.gz|tar xf -
+ cd libxml2-version
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ <screen>
+ gunzip -c libxslt-version.tar.gz|tar xf -
+ cd libxslt-version
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ </section>
+ <section id="usemarcon">
+ <title>USEMARCON (optional)</title>
+ <screen>
+ gunzip -c usemarcon317.tar.gz|tar xf -
+ cd usemarcon317
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ </section>
+
+ <section id="yaz.fromsource">
+ <title>YAZ/YAZ++</title>
+ <screen>
+ gunzip -c yaz-version.tar.gz|tar xf -
+ cd yaz-version
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ <screen>
+ gunzip -c yazpp-version.tar.gz|tar xf -
+ cd yazpp-version
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ </section>
+ <section>
+ <title id="boost.fromsource">Boost</title>
+ <para>
+ Metaproxy needs components thread and test from
+ Boost.
+ </para>
+ <screen>
+ gunzip -c boost-version.tar.gz|tar xf -
+ cd boost-version
+ ./configure --with-libraries=thread,test,regex --with-toolset=gcc
+ make
+ su
+ make install
+ </screen>
+ <para>
+ However, under the hood bjam is used. You can invoke that with
+ </para>
+ <screen>
+ ./bjam --toolset=gcc --with-thread --with-test --with-regex stage
+ </screen>
+ <para>
+ Replace <literal>stage</literal> with <literal>clean</literal> /
+ <literal>install</literal> to perform clean and install respectively.
+ </para>
+ <para>
+ Add <literal>--prefix=DIR</literal> to install Boost in other
+ prefix than <literal>/usr/local</literal>.
+ </para>
+ </section>
+ <section id="metaproxy.fromsource">
+ <title>Metaproxy</title>
+ <screen>
+ gunzip -c metaproxy-version.tar.gz|tar xf -
+ cd metaproxy-version
+ ./configure
+ make
+ su
+ make install
+ </screen>
+ <para>
+ You may have to tell configure where Boost is installed by supplying
+ options <literal>--with-boost</literal> and <literal>--with-boost-toolset</literal>.
+ The former sets the PREFIX for Boost (same as --prefix for Boost above).
+ The latter the compiler toolset (eg. gcc34).
+ </para>
+ <para>
+ Pass <literal>--help</literal> to configure to get a list of
+ available options.
+ </para>
+ </section>
</section>
<section id="installation.debian">
<title>Installation on Debian GNU/Linux</title>
<para>
- All dependencies for Metaproxy are available as
- <ulink url="&url.debian;">Debian</ulink>
- packages for the sarge (stable in 2005) and etch (testing in 2005)
- distributions.
+ All dependencies for Metaproxy are available as
+ <ulink url="&url.debian;">Debian</ulink> packages.
</para>
<para>
The procedures for Debian based systems, such as
</para>
<para>
There is currently no official Debian package for YAZ++.
- And the Debian package for YAZ is probably too old.
+ And the official Debian package for YAZ is probably too old.
+ But Index Data builds "new" versions of those for Debian (i386, amd64 only).
+ </para>
+ <para>
Update the <filename>/etc/apt/sources.list</filename>
to include the Index Data repository.
See YAZ' <ulink url="&url.yaz.download.debian;">Download Debian</ulink>
</para>
<screen>
apt-get install libxslt1-dev
- apt-get install libyazpp-dev
+ apt-get install libyazpp6-dev
apt-get install libboost-dev
+ apt-get install libboost-system-dev
apt-get install libboost-thread-dev
- apt-get install libboost-date-time-dev
- apt-get install libboost-program-options-dev
apt-get install libboost-test-dev
+ apt-get install libboost-regex-dev
</screen>
<para>
With these packages installed, the usual configure + make
</para>
</section>
+ <section id="installation.rpm">
+ <title>Installation on RPM based Linux Systems</title>
+ <para>
+ All external dependencies for Metaproxy are available as
+ RPM packages, either from your distribution site, or from the
+ <ulink url="http://fr.rpmfind.net/">RPMfind</ulink> site.
+ </para>
+ <para>
+ For example, an installation of the requires Boost C++ development
+ libraries on RedHat Fedora C4 and C5 can be done like this:
+ <screen>
+ wget ftp://fr.rpmfind.net/wlinux/fedora/core/updates/testing/4/SRPMS/boost-1.33.0-3.fc4.src.rpm
+ sudo rpmbuild --buildroot src/ --rebuild -p fc4/boost-1.33.0-3.fc4.src.rpm
+ sudo rpm -U /usr/src/redhat/RPMS/i386/boost-*rpm
+ </screen>
+ </para>
+ <para>
+ The <ulink url="&url.yaz;">YAZ</ulink> library is needed to
+ compile &metaproxy;, see there
+ for more information on available RPM packages.
+ </para>
+ <para>
+ There is currently no official RPM package for YAZ++.
+ See the <ulink url="&url.yazplusplus;">YAZ++</ulink> pages
+ for more information on a Unix tarball install.
+ </para>
+ <para>
+ With these packages installed, the usual configure + make
+ procedure can be used for Metaproxy as outlined in
+ <xref linkend="installation.unix"/>.
+ </para>
+ </section>
+
<section id="installation.windows">
<title>Installation on Windows</title>
<para>
- Metaproxy can be compiled with Microsoft
+ Metaproxy has been tested Microsoft
<ulink url="&url.vstudio;">Visual Studio</ulink>.
- Version 2003 (C 7.1) and 2005 (C 8.0) is known to work.
+ 2013 (C 12.0).
</para>
<section id="installation.windows.boost">
<title>Boost</title>
<para>
- Get Boost from its <ulink url="&url.boost;">home page</ulink>.
- You also need Boost Jam (an alternative to make).
- That's also available from the Boost home page.
- The files to be downloaded are called something like:
- <filename>boost_1_33-1.exe</filename>
- and
- <filename>boost-jam-3.1.12-1-ntx86.zip</filename>.
- Unpack Boost Jam first. Put <filename>bjam.exe</filename>
- in your system path. Make a command prompt and ensure
- it can be found automatically. If not check the PATH.
- The Boost .exe is a self-extracting exe with
- complete source for Boost. Compile that source with
- Boost Jam (An alternative to Make).
- The compilation takes a while.
- For Visual Studio 2003, use
- <screen>
- bjam "-sTOOLS=vc-7_1"
- </screen>
- Here <literal>vc-7_1</literal> refers to a "Toolset" (compiler system).
- For Visual Studio 2005, use
- <screen>
- bjam "-sTOOLS=vc-8_0"
- </screen>
- To install the libraries in a common place, use
- <screen>
- bjam "-sTOOLS=vc-7_1" install
- </screen>
- (or vc-8_0 for VS 2005).
- </para>
- <para>
- By default, the Boost build process installs the resulting
- libraries + header files in
- <literal>\boost\lib</literal>, <literal>\boost\include</literal>.
+ For Windows, it's easiest to get the precompiled Boost
+ package from <ulink url="&url.boost.windows.download;">here</ulink>.
+ Several versions of the Boost libraries may be selected when
+ installing Boost for windows. Please choose at least the
+ <emphasis>multithreaded</emphasis> (non-DLL) version because
+ the Metaproxy makefile uses that.
</para>
<para>
For more information about installing Boost refer to the
<para>
<ulink url="&url.libxslt;">Libxslt</ulink> can be downloaded
for Windows from
- <ulink url="&url.libxml2.download.win32;">here</ulink>.
+ <ulink url="&url.libxml2.download.windows;">here</ulink>.
</para>
<para>
- Libxslt has other dependencies, but these can all be downloaded
- from the same site. Get the following:
- iconv, zlib, libxml2, libxslt.
+ Libxslt also requires libxml2 to operate.
</para>
</section>
<title>YAZ++</title>
<para>
Get <ulink url="&url.yazplusplus;">YAZ++</ulink> as well.
- Version 1.0 or later is required. For now get it from
- Index Data's
- <ulink url="&url.snapshot.download;">Snapshot area</ulink>.
+ Version 1.6.0 or later is required.
</para>
<para>
YAZ++ includes NMAKE makefiles, similar to those found in the
</para>
</listitem>
</varlistentry>
-
+
</variablelist>
-
+
<para>
After successful compilation you'll find
<literal>metaproxy.exe</literal> in the
</section>
</chapter>
-
+
+<chapter id="yazproxy-comparison">
+ <title>YAZ Proxy Comparison</title>
+ <para>
+ The table below lists facilities either supported by either
+ <ulink url="&url.yazproxy;">YAZ Proxy</ulink> or Metaproxy.
+ </para>
+<table id="yazproxy-comparison-table">
+ <title>Metaproxy / YAZ Proxy comparison</title>
+ <tgroup cols="3">
+ <thead>
+ <row>
+ <entry>Facility</entry>
+ <entry>Metaproxy</entry>
+ <entry>YAZ Proxy</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Z39.50 server</entry>
+ <entry>Using filter <xref linkend="ref-frontend_net"/></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>SRU server</entry>
+ <entry>Supported with filter <xref linkend="ref-sru_z3950"/></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Z39.50 client</entry>
+ <entry>Supported with filter <xref linkend="ref-z3950_client"/></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>SRU client</entry>
+ <entry>Supported with filter <xref linkend="ref-zoom"/></entry>
+ <entry>Unsupported</entry>
+ </row>
+ <row>
+ <entry>Connection reuse</entry>
+ <entry>Supported with filter <literal>session_shared</literal></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Connection share</entry>
+ <entry>Supported with filter <literal>session_shared</literal></entry>
+ <entry>Unsupported</entry>
+ </row>
+ <row>
+ <entry>Result set reuse</entry>
+ <entry>Supported with filter <literal>session_shared</literal></entry>
+ <entry>Within one Z39.50 session / HTTP keep-alive</entry>
+ </row>
+ <row>
+ <entry>Record cache</entry>
+ <entry>Supported by filter <literal>session_shared</literal></entry>
+ <entry>Supported for last result set within one Z39.50/HTTP-keep alive session</entry>
+ </row>
+ <row>
+ <entry>Z39.50 Virtual database, i.e. select any Z39.50 target for database</entry>
+ <entry>Supported with filter <literal>virt_db</literal></entry>
+ <entry>Unsupported</entry>
+ </row>
+ <row>
+ <entry>SRU Virtual database, i.e. select any Z39.50 target for path</entry>
+ <entry>Supported with filter <literal>virt_db</literal>,
+ <literal>sru_z3950</literal></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Multi target search</entry>
+ <entry>Supported with filter <literal>multi</literal> (round-robin)</entry>
+ <entry>Unsupported</entry>
+ </row>
+ <row>
+ <entry>Retrieval and search limits</entry>
+ <entry>Supported using filter <literal>limit</literal></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Bandwidth limits</entry>
+ <entry>Supported using filter <literal>limit</literal></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Connect limits</entry>
+ <entry>Supported by filter <literal>frontend_net</literal> (connect-max)</entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Retrieval sanity check and conversions</entry>
+ <entry>Supported using filter <literal>record_transform</literal></entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Query check</entry>
+ <entry>
+ Supported by <literal>query_rewrite</literal> which may be check
+ a query and throw diagnostics (errors)
+ </entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Query rewrite</entry>
+ <entry>Supported with <literal>query_rewrite</literal></entry>
+ <entry>Unsupported</entry>
+ </row>
+ <row>
+ <entry>Session invalidate for -1 hits</entry>
+ <entry>Unsupported</entry>
+ <entry>Supported</entry>
+ </row>
+ <row>
+ <entry>Architecture</entry>
+ <entry>Multi-threaded + select for networked modules such as
+ <literal>frontend_net</literal>)</entry>
+ <entry>Single-threaded using select</entry>
+ </row>
+
+ <row>
+ <entry>Extensability</entry>
+ <entry>Most functionality implemented as loadable modules</entry>
+ <entry>Unsupported and experimental</entry>
+ </row>
+
+ <row>
+ <entry><ulink url="&url.usemarcon;">USEMARCON</ulink></entry>
+ <entry>Supported with <literal>record_transform</literal></entry>
+ <entry>Supported</entry>
+ </row>
+
+ <row>
+ <entry>Portability</entry>
+ <entry>
+ Requires YAZ, YAZ++ and modern C++ compiler supporting
+ <ulink url="&url.boost;">Boost</ulink>.
+ </entry>
+ <entry>
+ Requires YAZ and YAZ++.
+ STL is not required so pretty much any C++ compiler out there should work.
+ </entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+</table>
+</chapter>
+
<chapter id="architecture">
<title>The Metaproxy Architecture</title>
<para>
plugins that provide new filters. The filter API is small and
conceptually simple, but there are many details to master. See
the section below on
- <link linkend="extensions">extensions</link>.
+ <link linkend="filters">Filters</link>.
</para>
</listitem>
</varlistentry>
<chapter id="filters">
<title>Filters</title>
-
-
- <section>
+
+
+ <section id="filters-introductory-notes">
<title>Introductory notes</title>
<para>
It's useful to think of Metaproxy as an interpreter providing a small
others are sinks: they consume packages and return a result
(<literal>backend_test</literal>,
<literal>bounce</literal>,
- <literal>http_file</literal>,
+ <literal>http_file</literal>,
<literal>z3950_client</literal>);
the others are true filters, that read, process and pass on the
packages they are fed
<literal>virt_db</literal>).
</para>
</section>
-
-
+
+
<section id="overview.filter.types">
<title>Overview of filter types</title>
<para>
the core Metaproxy binary. This overview is intended to give a
flavor of the available functionality; more detailed information
about each type of filter is included below in
- <link linkend="filterref"
- >the reference guide to Metaproxy filters</link>.
+ <xref linkend="reference"/>.
</para>
<para>
The filters are here named by the string that is used as the
<para>
The filters are here listed in alphabetical order:
</para>
-
+
<!--
### New filters:
-->
- <section>
+ <section id="auth_simple">
<title><literal>auth_simple</literal>
(mp::filter::AuthSimple)</title>
<para>
the user.
</para>
</section>
-
- <section>
+
+ <section id="backend_test">
<title><literal>backend_test</literal>
(mp::filter::Backend_test)</title>
<para>
even read this section.
</para>
</section>
-
- <section>
+
+ <section id="bounce">
<title><literal>bounce</literal>
(mp::filter::Bounce)</title>
<para>
- A sink that swallows <emphasis>all packages</emphasis>,
+ A sink that swallows <emphasis>all packages</emphasis>,
and returns them almost unprocessed.
It never sends any package of any type further down the row, but
sets Z39.50 packages to Z_Close, and HTTP_Request packages to
HTTP_Response err code 400 packages, and adds a suitable bounce
- message.
- The bounce filter is usually added at end of each filter chain
- config.xml to prevent infinite hanging of for example HTTP
- requests packages when only the Z39.50 client partial sink
+ message.
+ The bounce filter is usually added at end of each filter chain route
+ to prevent infinite hanging of for example HTTP
+ requests packages when only the Z39.50 client partial sink
filter is found in the
- route.
+ route.
</para>
</section>
-
- <section>
+
+ <section id="cql_rpn">
+ <title><literal>cql_rpn</literal>
+ (mp::filter::CQLtoRPN)</title>
+ <para>
+ A query language transforming filter which catches Z39.50
+ <literal>searchRequest</literal>
+ packages containing <literal>CQL</literal> queries, transforms
+ those to <literal>RPN</literal> queries,
+ and sends the <literal>searchRequests</literal> on to the next
+ filters. It is among other things useful in a SRU context.
+ </para>
+ </section>
+
+ <section id="frontend_net">
<title><literal>frontend_net</literal>
(mp::filter::FrontendNet)</title>
<para>
</para>
</section>
- <section>
+ <section id="http_file">
<title><literal>http_file</literal>
(mp::filter::HttpFile)</title>
<para>
- A partial sink which swallows only HTTP_Request packages, and
+ A partial sink which swallows only
+ <literal>HTTP_Request</literal> packages, and
returns the contents of files from the local
- filesystem in response to HTTP requests.
+ filesystem in response to HTTP requests.
It lets Z39.50 packages and all other forthcoming package types
- pass untouched.
+ pass untouched.
(Yes, Virginia, this
does mean that Metaproxy is also a Web-server in its spare time. So
far it does not contain either an email-reader or a Lisp
interpreter, but that day is surely coming.)
</para>
</section>
-
- <section>
+
+ <section id="load_balance">
<title><literal>load_balance</literal>
(mp::filter::LoadBalance)</title>
<para>
Performs load balancing for incoming Z39.50 init requests.
It is used together with the <literal>virt_db</literal> filter,
but unlike the <literal>multi</literal> filter it does send an
- entire session to only one of the virtual backends. The
+ entire session to only one of the virtual backends. The
<literal>load_balance</literal> filter is assuming that
all backend targets have equal content, and chooses the backend
with least load cost for a new session.
</warning>
</para>
</section>
-
- <section>
+
+ <section id="log">
<title><literal>log</literal>
(mp::filter::Log)</title>
<para>
</para>
</section>
- <section>
+ <section id="multi">
<title><literal>multi</literal>
(mp::filter::Multi)</title>
<para>
of virtual databases and multi-database searching below.
</para>
</section>
-
- <section>
+
+ <section id="query_rewrite">
<title><literal>query_rewrite</literal>
(mp::filter::QueryRewrite)</title>
<para>
- Rewrites Z39.50 Type-1 and Type-101 (``RPN'') queries by a
+ Rewrites Z39.50 <literal>Type-1</literal>
+ and <literal>Type-101</literal> (``<literal>RPN</literal>'')
+ queries by a
three-step process: the query is transliterated from Z39.50
packet structures into an XML representation; that XML
representation is transformed by an XSLT stylesheet; and the
structure.
</para>
</section>
-
-
- <section>
+
+
+ <section id="record_transform">
<title><literal>record_transform</literal>
(mp::filter::RecordTransform)</title>
<para>
</para>
</section>
- <section>
+ <section id="session_shared">
<title><literal>session_shared</literal>
(mp::filter::SessionShared)</title>
<para>
- When this is finished, it will implement global sharing of
+ This filter implements global sharing of
result sets (i.e. between threads and therefore between
- clients), yielding performance improvements especially when
- incoming requests are from a stateless environment such as a
- web-server, in which the client process representing a session
- might be any one of many. However:
+ clients), yielding performance improvements by clever resource
+ pooling.
</para>
- <warning>
- <para>
- This filter is not yet completed.
- </para>
- </warning>
</section>
- <section>
+ <section id="sru_z3950">
<title><literal>sru_z3950</literal>
(mp::filter::SRUtoZ3950)</title>
<para>
messages.
The <literal>sru_z3950</literal> filter processes also SRU
GET/POST/SOAP explain requests, returning
- either the absolute minimum required by the standard, or a full
+ either the absolute minimum required by the standard, or a full
pre-defined ZeeReX explain record.
- See the
+ See the
<ulink url="&url.zeerex.explain;">ZeeReX Explain</ulink>
- standard pages and the
+ standard pages and the
<ulink url="&url.sru.explain;">SRU Explain</ulink> pages
for more information on the correct explain syntax.
SRU scan requests are not supported yet.
</para>
</section>
-
- <section>
+
+ <section id="template">
<title><literal>template</literal>
(mp::filter::Template)</title>
<para>
intended for civilians.
</para>
</section>
-
- <section>
+
+ <section id="virt_db">
<title><literal>virt_db</literal>
(mp::filter::VirtualDB)</title>
<para>
of virtual databases and multi-database searching below.
</para>
</section>
-
- <section>
+
+ <section id="z3950_client">
<title><literal>z3950_client</literal>
(mp::filter::Z3950Client)</title>
<para>
the route. Subsequent requests are sent to the same address,
which is remembered at Init time in a Session object.
HTTP_Request packages and all other forthcoming package types
- are passed untouched.
+ are passed untouched.
</para>
</section>
- <section>
+ <section id="zeerex_explain">
<title><literal>zeerex_explain</literal>
(mp::filter::ZeerexExplain)</title>
<para>
Z39.50 explain requests, returning a static ZeeReX
Explain XML record from the config section. All other packages
are passed through.
- See the
+ See the
<ulink url="&url.zeerex.explain;">ZeeReX Explain</ulink>
standard pages
for more information on the correct explain syntax.
</para>
</warning>
</section>
-
+
</section>
-
-
+
+
<section id="future.directions">
<title>Future directions</title>
<para>
</variablelist>
</section>
</chapter>
-
-
-
+
+
+
<chapter id="configuration">
<title>Configuration: the Metaproxy configuration file format</title>
-
-
- <section>
+
+
+ <section id="configuration-introductory-notes">
<title>Introductory notes</title>
<para>
If Metaproxy is an interpreter providing operations on packages, then
interpreter. Configuration is by means of a single XML file, the name
of which is supplied as the sole command-line argument to the
<command>metaproxy</command> program. (See
- <link linkend="progref">the reference guide</link>
- below for more information on invoking Metaproxy.)
+ <xref linkend="reference"/> below for more information on invoking
+ Metaproxy.)
</para>
</section>
-
+
<section id="overview.xml.structure">
<title>Overview of the config file XML structure</title>
<para>
<metaproxy xmlns="http://indexdata.com/metaproxy" version="1.0">
</screen>
<para>
- The top-level element is <metaproxy>. This contains a
- <start> element, a <filters> element and a
- <routes> element, in that order. <filters> is
- optional; the other two are mandatory. All three are
- non-repeatable.
+ The top-level element is <metaproxy>. This contains
+ a <dlpath> element,
+ a <start> element,
+ a <filters> element and
+ a <routes> element, in that order. <dlpath> and
+ <filters> are optional; the other two are mandatory.
+ All four are non-repeatable.
+ </para>
+ <para>
+ The <dlpath;> element contains a text element which
+ specifies the location of filter modules. This is only needed
+ if Metaproxy must load 3rd party filters (most filters with Metaproxy
+ are built into the Metaproxy application).
</para>
<para>
The <start> element is empty, but carries a
and contain various elements that provide suitable configuration
for a filter of its type. The filter-specific elements are
described in
- <link linkend="filterref">the reference guide below</link>.
+ <xref linkend="reference"/>.
Filters defined in this part of the file must carry an
<literal>id</literal> attribute so that they can be referenced
from elsewhere.
</para>
<screen><![CDATA[<?xml version="1.0"?>
<metaproxy xmlns="http://indexdata.com/metaproxy" version="1.0">
+ <dlpath>/usr/lib/metaproxy/modules</dlpath>
<start route="start"/>
<filters>
<filter id="frontend" type="frontend_net">
<filter id="backend" type="z3950_client">
</filter>
</filters>
- <routes>
+ <routes>
<route id="start">
<filter refid="frontend"/>
<filter type="log"/>
mutton, beef and trout packages.
When the response arrives, it is handed
back to the <literal>log</literal> filter, which emits another
- message; and then to the <literal>frontend_net</literal> filter,
+ message; and then to the <literal>frontend_net</literal> filter,
which returns the response to the client.
</para>
</section>
- <section id="checking.xml.syntax">
+
+ <section id="config-file-modularity">
+ <title>Config file modularity</title>
+ <para>
+ Metaproxy XML configuration snippets can be reused by other
+ filters using the <literal>XInclude</literal> standard, as seen in
+ the <literal>/etc/config-sru-to-z3950.xml</literal> example SRU
+ configuration.
+ <screen><![CDATA[
+ <filter id="sru" type="sru_z3950">
+ <database name="Default">
+ <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
+ href="explain.xml"/>
+ </database>
+ </filter>
+]]></screen>
+ </para>
+ </section>
+
+ <section id="config-file-syntax-check">
<title>Config file syntax checking</title>
<para>
The distribution contains RelaxNG Compact and XML syntax checking
files, as well as XML Schema files. These are found in the
- distribution paths
+ distribution paths
<screen>
xml/schema/metaproxy.rnc
xml/schema/metaproxy.rng
configuration files. For example, using the utility
<filename>xmllint</filename>, syntax checking is done like this:
<screen>
- xmllint --noout --schema xml/schema/metaproxy.xsd etc/config-local.xml
- xmllint --noout --relaxng xml/schema/metaproxy.rng etc/config-local.xml
+ xmllint --noout --schema xml/schema/metaproxy.xsd etc/config-local.xml
+ xmllint --noout --relaxng xml/schema/metaproxy.rng etc/config-local.xml
</screen>
(A recent version of <literal>libxml2</literal> is required, as
support for XML Schemas is a relatively recent addition.)
<title>Virtual databases and multi-database searching</title>
- <section>
+ <section id="multidb-introductory-notes">
<title>Introductory notes</title>
<para>
Two of Metaproxy's filters are concerned with multiple-database
<screen><![CDATA[<filter type="virt_db">
<virtual>
<database>lc</database>
- <target>z3950.loc.gov:7090/voyager</target>
+ <target>lx2.loc.gov:210/LCDB</target>
</virtual>
<virtual>
<database>marc</database>
<filter type="virt_db">
<virtual>
<database>lc</database>
- <target>z3950.loc.gov:7090/voyager</target>
+ <target>lx2.loc.gov:210/LCDB</target>
</virtual>
<virtual>
<database>marc</database>
</virtual>
<virtual>
<database>all</database>
- <target>z3950.loc.gov:7090/voyager</target>
+ <target>lx2.loc.gov:210/LCDB</target>
<target>indexdata.com/marc</target>
</virtual>
</filter>
merges them into a single Search response, which is what
eventually makes it back to the client.
</para>
- </section>
-
- <section id="multidb.picture">
- <title>A picture is worth a thousand words (but only five hundred on 64-bit architectures)</title>
- <simpara>
- <inlinemediaobject>
+ <mediaobject>
<imageobject>
<imagedata fileref="multi.pdf" format="PDF" scale="50"/>
</imageobject>
document.]
</phrase>
</textobject>
-<!-- ### This used to work with an older version of DocBook
<caption>
- <para>Caption: progress of packages through filters.</para>
+ <para>A picture is worth a thousand words (but only five hundred on 64-bit architectures)</para>
</caption>
--->
- </inlinemediaobject>
- </simpara>
+ </mediaobject>
</section>
</chapter>
+ <chapter id="sru-server">
+ <title>Combined SRU webservice and Z39.50 server configuration</title>
+ <para>
+ Metaproxy can act as
+ <ulink url="&url.sru;">SRU</ulink> and
+ web service server, which translates web service requests to
+ <ulink url="&url.z39.50;">ANSI/NISO Z39.50</ulink> packages and
+ sends them off to common available targets.
+ </para>
+ <para>
+ A typical setup for this operation needs a filter route including the
+ following modules:
+ </para>
+ <table id="sru-server-table-config" frame="top">
+ <title>SRU/Z39.50 Server Filter Route Configuration</title>
+ <tgroup cols="3">
+ <thead>
+ <row>
+ <entry>Filter</entry>
+ <entry>Importance</entry>
+ <entry>Purpose</entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry><literal>frontend_net</literal></entry>
+ <entry>required</entry>
+ <entry>Accepting HTTP connections and passing them to following
+ filters. Since this filter also accepts Z39.50 connections, the
+ server works as SRU and Z39.50 server on the same port.</entry>
+ </row>
+ <row>
+ <entry><literal>sru_z3950</literal></entry>
+ <entry>required</entry>
+ <entry>Accepting SRU GET/POST/SOAP explain and
+ searchRetrieve requests for the the configured databases.
+ Explain requests are directly served from the static XML configuration.
+ SearchRetrieve requests are
+ transformed to Z39.50 search and present packages.
+ All other HTTP and Z39.50 packages are passed unaltered.</entry>
+ </row>
+ <row>
+ <entry><literal>http_file</literal></entry>
+ <entry>optional</entry>
+ <entry>Serving HTTP requests from the filesystem. This is only
+ needed if the server should serve XSLT stylesheets, static HTML
+ files or Java Script for thin browser based clients.
+ Z39.50 packages are passed unaltered.</entry>
+ </row>
+ <row>
+ <entry><literal>cql_rpn</literal></entry>
+ <entry>required</entry>
+ <entry>Usually, Z39.50 servers do not talk CQL, hence the
+ translation of the CQL query language to RPN is mandatory in
+ most cases. Affects only Z39.50 search packages.</entry>
+ </row>
+ <row>
+ <entry><literal>record_transform</literal></entry>
+ <entry>optional</entry>
+ <entry>Some Z39.50 backend targets can not present XML record
+ syntaxes in common wanted element sets. using this filter, one
+ can transform binary MARC records to MARCXML records, and
+ further transform those to any needed XML schema/format by XSLT
+ transformations. Changes only Z39.50 present packages.</entry>
+ </row>
+ <row>
+ <entry><literal>session_shared</literal></entry>
+ <entry>optional</entry>
+ <entry>The stateless nature of web services requires frequent
+ re-searching of the same targets for display of paged result set
+ records. This might be an unacceptable burden for the accessed
+ backend Z39.50 targets, and this mosule can be added for
+ efficient backend target resource pooling.</entry>
+ </row>
+ <row>
+ <entry><literal>z3950_client</literal></entry>
+ <entry>required</entry>
+ <entry>Finally, a Z39.50 package sink is needed in the filter
+ chain to provide the response packages. The Z39.50 client module
+ is used to access external targets over the network, but any
+ coming local Z39.50 package sink could be used instead of.</entry>
+ </row>
+ <row>
+ <entry><literal>bounce</literal></entry>
+ <entry>required</entry>
+ <entry>Any Metaproxy package arriving here did not do so by
+ purpose, and is bounced back with connection closure. this
+ prevents inifinite package hanging inside the SRU server.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <para>
+ A typical minimal example <ulink url="&url.sru;">SRU</ulink>
+ server configuration file is found in the tarball distribution at
+ <literal>etc/config-sru-to-z3950.xml</literal>.
+ </para>
+ <para>
+ Off course, any other metaproxy modules can be integrated into a
+ SRU server solution, including, but not limited to, load balancing,
+ multiple target querying
+ (see <xref linkend="multidb"/>), and complex RPN query rewrites.
+ </para>
+
+
+ </chapter>
+
+ <!--
<chapter id="extensions">
<title>Writing extensions for Metaproxy</title>
<para>### To be written</para>
</chapter>
-
+ -->
<title>Classes in the Metaproxy source code</title>
- <section>
+ <section id="classes-introductory-notes">
<title>Introductory notes</title>
<para>
<emphasis>Stop! Do not read this!</emphasis>
You won't enjoy it at all. You should just skip ahead to
- <link linkend="refguide">the reference guide</link>,
+ <xref linkend="reference"/>,
which tells
<!-- The remainder of this paragraph is lifted verbatim from
Douglas Adams' _Hitch Hiker's Guide to the Galaxy_, chapter 8 -->
parentheses.
</para>
- <section>
+ <section id="class-FactoryFilter">
<title><literal>mp::FactoryFilter</literal>
(<filename>factory_filter.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-FactoryStatic">
<title><literal>mp::FactoryStatic</literal>
(<filename>factory_static.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-filter-Base">
<title><literal>mp::filter::Base</literal>
(<filename>filter.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-AuthSimple">
<title><literal>mp::filter::AuthSimple</literal>,
<literal>Backend_test</literal>, etc.
(<filename>filter_auth_simple.cpp</filename>,
</itemizedlist>
</section>
- <section>
+ <section id="class-Package">
<title><literal>mp::Package</literal>
(<filename>package.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-Pipe">
<title><literal>mp::Pipe</literal>
(<filename>pipe.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-RouterChain">
<title><literal>mp::RouterChain</literal>
(<filename>router_chain.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-RouterFleXML">
<title><literal>mp::RouterFleXML</literal>
(<filename>router_flexml.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-Session">
<title><literal>mp::Session</literal>
(<filename>session.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-ThreadPoolSocketObserver">
<title><literal>mp::ThreadPoolSocketObserver</literal>
(<filename>thread_pool_observer.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-util">
<title><literal>mp::util</literal>
(<filename>util.cpp</filename>)</title>
<para>
</para>
</section>
- <section>
+ <section id="class-xml">
<title><literal>mp::xml</literal>
(<filename>xmlutil.cpp</filename>)</title>
<para>
</para>
</section>
</chapter>
-
-
-
- <reference id="refguide">
- <title>Reference guide</title>
+
+
+ <reference id="reference">
+ <title>Reference</title>
+ <partintro id="reference-introduction">
<para>
The material in this chapter is drawn directly from the individual
manual entries. In particular, the Metaproxy invocation section is
on each individual filter is available using the name of the filter
as the argument to the <command>man</command> command.
</para>
- &manref;
+ </partintro>
+ &manref;
</reference>
+
+<appendix id="license">
+ <title>License</title>
+
+ ©right;
+
+ <para>
+ Metaproxy is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 2, or (at your option) any later
+ version.
+ </para>
+
+ <para>
+ Metaproxy is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+ </para>
+
+ <para>
+ You should have received a copy of the GNU General Public License
+ along with Metaproxy; see the file LICENSE. If not, write to the
+ Free Software Foundation,
+ 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ </para>
+
+ </appendix>
+
+ &gpl2;
</book>
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- mode: sgml
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- sgml-parent-document: nil
- sgml-local-catalogs: nil
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- End:
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+<!-- Keep this comment at the end of the file
+Local variables:
+mode: nxml
+nxml-child-indent: 1
+End:
+-->
projects / metaproxy-moved-to-github.git / blobdiff