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14 <title>YAZ User's Guide and Reference</title>
16 <author><firstname>Sebastian</firstname><surname>Hammer</surname></author>
17 <author><firstname>Adam</firstname><surname>Dickmeiss</surname></author>
18 <author><firstname>Mike</firstname><surname>Taylor</surname></author>
19 <author><firstname>Heikki</firstname><surname>Levanto</surname></author>
20 <author><firstname>Dennis</firstname><surname>Schafroth</surname></author>
22 <releaseinfo>&version;</releaseinfo>
24 <year>©right-year;</year>
25 <holder>Index Data</holder>
29 This document is the programmer's guide and reference to the &yaz;
30 package version &version;. &yaz; is a compact toolkit that provides
31 access to the Z39.50 and SRU/Solr protocols, as well as a set of
32 higher-level tools for implementing the server and client
34 The documentation can be used on its own, or as a reference when
35 looking at the example applications provided with the package.
40 <imagedata fileref="common/id.png" format="PNG"/>
43 <imagedata fileref="common/id.eps" format="EPS"/>
48 <chapter id="introduction">
49 <title>Introduction</title>
51 &yaz; is a C/C++ library for information retrieval applications
52 using the Z39.50/SRU/Solr protocols for information retrieval.
60 <ulink url="&url.z39.50;">Z39.50</ulink> version 3 support.
61 Amendments and Z39.50-2002 revision is supported.
67 <ulink url="&url.sru;">SRU GET/POST/SOAP</ulink>
68 version 1.1, 1.2 and 2.0 (over HTTP and HTTPS).
73 Includes BER encoders/decoders for the
74 <ulink url="&url.ill;">ISO ILL</ulink>
81 <ulink url="&url.solr;">Apache Solr</ulink> Web Service version 1.4.x
87 Supports the following transports: BER over TCP/IP
88 (<ulink url="&url.ber.over.tcpip;">RFC1729</ulink>),
89 BER over unix local socket, and
90 <ulink url="&url.http.1.1;">HTTP 1.1</ulink>.
95 Secure Socket Layer support using
96 <ulink url="&url.gnutls;">GnuTLS</ulink>.
97 If enabled, &yaz; uses HTTPS transport (for SOAP) or
98 "Secure BER" (for Z39.50).
104 <ulink url="&url.zoom;">ZOOM</ulink> C API implementing
105 Z39.50, SRU and Solr Web Service.
110 The &yaz; library offers a set of useful utilities
111 related to the protocols, such as MARC (ISO2709) parser,
112 CCL (ISO8777) parser,
113 <ulink url="&url.cql;">CQL</ulink>
114 parser, memory management routines, character set conversion.
119 Portable code. &yaz; compiles out-of-the box on most Unixes and
120 on Windows using Microsoft Visual C++.
125 Fast operation. The C based BER encoders/decoders as well
126 as the server component of &yaz; is very fast.
131 Liberal license that allows for commercial use of &yaz;.
137 <sect1 id="introduction.reading">
138 <title>Reading this Manual</title>
140 Most implementors only need to read a fraction of the
141 material in this manual, so a quick walkthrough of the chapters
147 <xref linkend="installation"/> contains installation
148 instructions for &yaz;. You don't need to read this
149 if you expect to download &yaz; binaries.
150 However, the chapter contains information about how
151 to make <emphasis>your</emphasis> application link
157 <xref linkend="zoom"/> describes the ZOOM API of &yaz;.
158 This is definitely worth reading if you wish to develop a Z39.50/SRU
164 <xref linkend="server"/> describes the generic frontend server
165 and explains how to develop server Z39.50/SRU applications for &yaz;.
166 Obviously worth reading if you're to develop a server.
171 <xref linkend="yaz-client"/> describes how to use the &yaz; Z39.50
172 client. If you're a developer and wish to test your server
173 or a server from another party, you might find this chapter
179 <xref linkend="asn"/> documents the most commonly used Z39.50
180 C data structures offered by the &yaz; API. Client
181 developers using ZOOM and non-Z39.50 implementors may skip this.
186 <xref linkend="soap"/> describes how SRU and SOAP is used
187 in &yaz;. Only if you're developing SRU applications
188 this section is a must.
193 <xref linkend="tools"/> contains sections for the various
194 tools offered by &yaz;. Scan through the material quickly
195 and see what's relevant to you! SRU implementors
196 might find the <link linkend="cql">CQL</link> section
202 <xref linkend="odr"/> goes through the details of the
203 ODR module which is the work horse that encodes and decodes
204 BER packages. Implementors using ZOOM only, do <emphasis>not</emphasis>
206 Most other Z39.50 implementors only need to read the first two
207 sections (<xref linkend="odr.introduction"/> and
208 <xref linkend="odr.use"/>).
213 <xref linkend="comstack"/> describes the network layer module
214 COMSTACK. Implementors using ZOOM or the generic frontend server
215 may skip this. Others, presumably, handling client/server
216 communication on their own should read this.
221 <sect1 id="introduction.api">
222 <title>The API</title>
224 The <ulink url="&url.yaz;">&yaz;</ulink>
225 toolkit offers several different levels of access to the
226 <ulink url="&url.z39.50;">ISO23950/Z39.50</ulink>,
227 <ulink url="&url.ill;">ILL</ulink> and
228 <ulink url="&url.sru;">SRU</ulink>
230 The level that you need to use depends on your requirements, and
231 the role (server or client) that you want to implement.
232 If you're developing a client application you should consider the
233 <link linkend="zoom">ZOOM</link> API.
234 It is, by far, the easiest way to develop clients in C.
235 Server implementers should consider the
236 <link linkend="server">generic frontend server</link>.
237 None of those high-level APIs support the whole protocol, but
238 they do include most facilities used in existing Z39.50 applications.
241 If you're using 'exotic' functionality (meaning anything not included in
242 the high-level APIs), developing non-standard extensions to Z39.50 or
243 you're going to develop an ILL application you'll have to learn the lower
247 The YAZ toolkit modules are shown in figure <xref linkend="yaz.layer"/>.
249 <figure id="yaz.layer">
250 <title>YAZ layers</title>
253 <imagedata fileref="apilayer.png" format="PNG"/>
256 <imagedata fileref="apilayer.eps" format="EPS"/>
261 There are four layers.
264 <para>A client or server application (or both).
265 This layer includes ZOOM and the generic frontend server.
270 The second layer provides a C represenation of the
271 protocol units (packages) for Z39.50 ASN.1, ILL ASN.1,
277 The third layer encodes and decodes protocol data units to
278 simple packages (buffer with certain length). The &odr; module
279 encodes and decodes BER whereas the HTTP modules encodes and
280 decodes HTTP ruquests/responses.
285 The lowest layer is &comstack; which exchanges the encoded packages
286 with a peer process over a network.
292 The &asn; module represents the ASN.1 definition of
293 the Z39.50 protocol. It establishes a set of type and
294 structure definitions, with one structure for each of the top-level
295 PDUs, and one structure or type for each of the contained ASN.1 types.
296 For primitive types, or other types that are defined by the ASN.1
297 standard itself (such as the EXTERNAL type), the C representation is
298 provided by the &odr; (Open Data Representation) subsystem.
301 &odr; is a basic mechanism for representing an
302 ASN.1 type in the C programming language, and for implementing BER
303 encoders and decoders for values of that type. The types defined in
304 the &asn; module generally have the prefix <literal>Z_</literal>, and
305 a suffix corresponding to the name of the type in the ASN.1
306 specification of the protocol (generally Z39.50-1995). In the case of
307 base types (those originating in the ASN.1 standard itself), the prefix
308 <literal>Odr_</literal> is sometimes seen. Either way, look for
309 the actual definition in either <filename>z-core.h</filename> (for the types
310 from the protocol), <filename>odr.h</filename> (for the primitive ASN.1
312 The &asn; library also provides functions (which are, in turn,
313 defined using &odr; primitives) for encoding and decoding data values.
314 Their general form is
316 <funcprototype><funcdef>int <function>z_<replaceable>xxx</replaceable></function></funcdef>
317 <paramdef>ODR <parameter>o</parameter></paramdef>
318 <paramdef>Z_<replaceable>xxx</replaceable> **<parameter>p</parameter></paramdef>
319 <paramdef>int <parameter>optional</parameter></paramdef>
320 <paramdef>const char *<parameter>name</parameter></paramdef>
323 (note the lower-case "z" in the function name)
327 If you are using the premade definitions of the &asn; module, and you
328 are not adding a new protocol of your own, the only parts of &odr; that you
329 need to worry about are documented in
330 <xref linkend="odr.use"/>.
334 When you have created a BER-encoded buffer, you can use the &comstack;
335 subsystem to transmit (or receive) data over the network. The &comstack;
336 module provides simple functions for establishing a connection
337 (passively or actively, depending on the role of your application),
338 and for exchanging BER-encoded PDUs over that connection. When you
339 create a connection endpoint, you need to specify what transport to
340 use (TCP/IP, SSL or UNIX sockets).
341 For the remainder of the connection's lifetime, you don't have
342 to worry about the underlying transport protocol at all - the &comstack;
343 will ensure that the correct mechanism is used.
346 We call the combined interfaces to &odr;, &asn;, and &comstack; the service
347 level API. It's the API that most closely models the Z39.50
348 service/protocol definition, and it provides unlimited access to all
349 fields and facilities of the protocol definitions.
352 The reason that the &yaz; service-level API is a conglomerate of the
353 APIs from three different submodules is twofold. First, we wanted to allow
354 the user a choice of different options for each major task. For instance,
355 if you don't like the protocol API provided by &odr;/&asn;, you
356 can use SNACC or BERUtils instead, and still have the benefits of the
357 transparent transport approach of the &comstack; module. Secondly,
358 we realize that you may have to fit the toolkit into an existing
359 event-processing structure, in a way that is incompatible with
360 the &comstack; interface or some other part of &yaz;.
364 <chapter id="installation">
365 <title>Compilation and Installation</title>
366 <sect1 id="installation-introduction">
367 <title>Introduction</title>
369 The latest version of the software will generally be found at:
372 <ulink url="&url.yaz.download;"/>
375 We have tried our best to keep the software portable, and on many
376 platforms, you should be able to compile everything with little or
380 The software is regularly tested on
381 <ulink url="&url.debian;">Debian GNU/Linux</ulink>,
382 <ulink url="&url.centos;">CentOS</ulink>,
383 <ulink url="&url.ubuntu;">Ubuntu Linux</ulink>,
384 <ulink url="&url.freebsd;">FreeBSD (i386)</ulink>,
385 <ulink url="&url.macosx;">MAC OSX</ulink>,
389 Some versions have be known to work on Windows XP, Solaris, HP/UX,
390 DEC Unix, <ulink url="&url.netbsd;">NetBSD</ulink>,
391 <ulink url="&url.openbsd;">OpenBSD</ulink>,
393 Data General DG/UX (with some CFLAGS tinkering),
394 SGI/IRIX, DDE Supermax, Apple Macintosh (using the Codewarrior programming
395 environment and the GUSI socket libraries),
399 If you move the software to other platforms, we'd be grateful if you'd
400 let us know about it. If you run into difficulties, we will try to help
401 if we can, and if you solve the problems, we would be happy to include
402 your fixes in the next release. So far, we have mostly avoided
403 <literal>#ifdefs</literal> for individual platforms, and we'd
404 like to keep it that way as far as it makes sense.
407 We maintain a mailing-list for the purpose of announcing new releases and
408 bug-fixes, as well as general discussion. Subscribe by
410 <ulink url="&url.yaz.mailinglist;">here</ulink>.
411 General questions and problems can be directed at
412 <ulink url="&url.yaz.mail;"/>, or the address given at the top of
416 <sect1 id="installation.unix"><title>UNIX</title>
419 <ulink url="&url.debian;">Debian GNU/Linux</ulink> (i386 and amd64),
420 <ulink url="&url.ubuntu;">Ubuntu</ulink> (i386 and amd64)
422 <ulink url="&url.centos;">CentOS</ulink> (amd64 only) packages for &yaz;.
423 You should be able to create packages for other CPUs by building
424 them from the source package.
427 YAZ is also part of several packages repositories. Some of them are
432 Solaris CSW: <ulink url="http://www.opencsw.org/packages/yaz/"/>
437 Solaris: <ulink url="http://unixpackages.com"/>
442 FreeBSD: <ulink url="http://www.freshports.org/net/yaz"/>
447 Debian: <ulink url="http://packages.debian.org/search?keywords=yaz"/>
452 Ubuntu: <ulink url="https://launchpad.net/ubuntu/+source/yaz"/>
458 <ulink url="http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/net/yaz/README.html"/>
462 <sect2 id="installation.source.unix">
463 <title>Compiling from source on Unix</title>
465 Note that if your system doesn't have a native ANSI C compiler, you may
466 have to acquire one separately. We recommend
467 <ulink url="&url.gcc;">GCC</ulink>.
470 If you wish to use character set conversion facilities in &yaz; or if you
471 are compiling &yaz; for use with Zebra it is a good idea to ensure that
472 the iconv library is installed. Some Unixes today already have it
474 <ulink url="&url.libiconv;">GNU libiconv</ulink>.
477 YAZ 3.0.16 and later includes a wrapper for the
478 <ulink url="&url.icu;">ICU</ulink>
479 (International Components for Unicode).
480 In order to use this, the developer version of the ICU library
481 must be available. ICU support is recommended for applications
482 such as Pazpar2 and Zebra.
485 The <ulink url="&url.libxslt;">libxslt</ulink>,
486 <ulink url="&url.libxml2;">libxml2</ulink> librararies are required
487 if &yaz; is to support SRU/Solr.
488 These libraries are very portable and should compile out-of-the
489 box on virtually all Unix platforms. It is available in binary
490 forms for Linux and others.
494 <ulink url="&url.autoconf;">Autoconf</ulink>,
495 <ulink url="&url.automake;">Automake</ulink> and
496 <ulink url="&url.libtool;">Libtool</ulink>
497 are used to generate Makefiles and configure &yaz; for the system.
498 You do <emphasis>not</emphasis> need these tools unless you're using the
499 Git version of &yaz;.
502 The CQL parser for &yaz; is built using
503 GNU <ulink url="&url.bison;">Bison</ulink>.
504 This tool is only needed if you're using the Git version of &yaz;.
507 &yaz; includes a tiny ASN.1 compiler. This compiler is
508 written in <ulink url="&url.tcl;">Tcl</ulink>.
509 But as for Bison you do not need it unless you're using Git
510 version of &yaz; or you're using the compiler to build your own codecs
514 Generally it should be sufficient to run configure without options,
521 The configure script attempts to use use the C compiler specified by
522 the <literal>CC</literal> environment variable. If not set, GNU C will be
523 used if it is available. The <literal>CFLAGS</literal> environment
524 variable holds options to be passed to the C compiler. If you're using
525 Bourne-compatible shell you may pass something like this to use a
526 particular C compiler with optimization enabled:
529 CC=/opt/ccs/bin/cc CFLAGS=-O ./configure
532 To customize &yaz;, the configure script also accepts a set of options.
533 The most important are:
537 <literal>--prefix</literal>=<replaceable>prefix</replaceable>
540 <para>Specifies installation prefix for &yaz;. This is
541 only needed if you run <literal>make install</literal> later to
542 perform a "system" installation. The prefix is
543 <literal>/usr/local</literal> if not specified.
549 <literal>--enable-tcpd</literal>
552 <para>The front end server will be built using Wietse's
553 <ulink url="&url.tcpwrapper;">TCP wrapper library</ulink>.
554 It allows you to allow/deny clients depending on IP number.
555 The TCP wrapper library is often used in GNU/Linux and
559 <refentrytitle>hosts_access</refentrytitle>
560 <manvolnum>5</manvolnum>
564 <refentrytitle>tcpd</refentrytitle>
565 <manvolnum>8</manvolnum>
572 <literal>--enable-threads</literal>
575 <para>&yaz; will be built using POSIX threads.
576 Specifically, <constant>_REENTRANT</constant> will be defined during
583 <literal>--disable-shared</literal>
586 <para>The make process will not create shared
587 libraries (also known as shared objects <filename>.so</filename>).
588 By default, shared libraries are created -
589 equivalent to <literal>--enable-shared</literal>.
595 <literal>--disable-shared</literal>
598 <para>The make process will not create
599 static libraries (<filename>.a</filename>).
600 By default, static libraries are created -
601 equivalent to <literal>--enable-static</literal>.
607 <literal>--with-iconv</literal>[=<replaceable>prefix</replaceable>]
610 <para>Compile &yaz; with iconv library in directory
611 <replaceable>prefix</replaceable>. By default configure will
612 search for iconv on the system. Use this option if it
613 doesn't find iconv. Alternatively,
614 <literal>--without-iconv</literal>, can be used to force &yaz;
621 <literal>--with-xslt</literal>[=<replaceable>prefix</replaceable>]
624 <para>Compile &yaz; with
625 <ulink url="&url.libxslt;">libxslt</ulink> in directory
626 <replaceable>prefix</replaceable>.
627 Use this option if you want XSLT and XML support.
628 By default, configure will
629 search for libxslt on the system. Use this option if
630 libxslt is not found automatically. Alternatively,
631 <literal>--without-xslt</literal>, can be used to force &yaz;
638 <literal>--with-xml2</literal>[=<replaceable>prefix</replaceable>]
641 <para>Compile &yaz; with
642 <ulink url="&url.libxml2;">libxml2</ulink> in directory
643 <replaceable>prefix</replaceable>.
644 Use this option if you want &yaz; to use XML and support SRU/Solr.
645 By default, configure will
646 search for libxml2 on the system. Use this option if
647 libxml2 is not found automatically. Alternatively,
648 <literal>--without-xml2</literal>, can be used to force &yaz;
652 Note that option <literal>--with-xslt</literal>
653 also enables libxml2.
659 <literal>--with-gnutls</literal>[=<replaceable>prefix</replaceable>]
662 <para>&yaz; will be linked with the GNU TLS libraries and
663 an SSL COMSTACK will be provided. By default configure enables
664 SSL support for YAZ if the GNU TLS development libraries are found
671 <literal>--with-icu</literal>[=<replaceable>prefix</replaceable>]
674 <para>&yaz; will be linked the
675 <ulink url="&url.icu;">ICU</ulink> library in the prefix if given.
676 If prefix is not given, the libraries exposed by the script
677 <application>icu-config</application> will be used if found.
684 <literal>--with-memcached</literal>
687 <para>&yaz; will be linked with
688 <ulink url="&url.libmemcached;">libMemcached</ulink> to allow
689 for result-set caching for ZOOM.
690 The prefix can not be given.
691 Note that 0.40 of libmemcached is required.
697 <literal>--with-redis</literal>
700 <para>&yaz; will be linked with the hiredis C library
701 to allow for result-set caching for ZOOM on a
702 <ulink url="&url.redis;">redis</ulink> server.
703 The prefix can not be given.
711 When configured, build the software by typing:
717 The following files are generated by the make process:
720 <term><filename>src/libyaz.la</filename></term>
722 Main &yaz; library. This is no ordinary library. It's
724 By default, &yaz; creates a static library in
725 <filename>lib/.libs/libyaz.a</filename>.
729 <term><filename>src/libyaz_server.la</filename></term>
731 Generic Frontend server. This is an add-on for libyaz.la.
732 Code in this library uses POSIX threads functions - if POSIX
733 threads are available on the platform.
737 <term><filename>src/libyaz_icu.la</filename></term>
739 Functions that wrap the ICU library.
743 <term><filename>ztest/yaz-ztest</filename></term>
744 <listitem><para>Test Z39.50 server.
748 <term><filename>client/yaz-client</filename></term>
749 <listitem><para>Z39.50 client for testing the protocol.
750 See chapter <link linkend="yaz-client">
751 YAZ client</link> for more information.
755 <term><filename>util/yaz-config</filename></term>
756 <listitem><para>A Bourne-shell script, generated by configure, that
757 specifies how external applications should compile - and link with
762 <term><filename>util/yaz-asncomp</filename></term>
763 <listitem><para>The ASN.1 compiler for &yaz;. Requires the
764 Tcl Shell, <application>tclsh</application>, in
765 <literal>PATH</literal> to operate.
769 <term><filename>util/yaz-iconv</filename></term>
770 <listitem><para>This program converts data in one character set to
771 another. This command exercises the YAZ character set
776 <term><filename>util/yaz-marcdump</filename></term>
777 <listitem><para>This program parses ISO2709 encoded MARC records
778 and prints them in line-format or XML.
782 <term><filename>util/yaz-icu</filename></term>
783 <listitem><para>This program exposes the ICU wrapper library if that
784 is enabled for YAZ. Only if ICU is available this program is
789 <term><filename>util/yaz-url</filename></term>
790 <listitem><para>This program is a simple HTTP page fetcher ala
795 <term><filename>zoom/zoomsh</filename></term>
797 A simple shell implemented on top of the
798 <link linkend="zoom">ZOOM</link> functions.
799 The shell is a command line application that allows you to enter
800 simple commands to perform ZOOM operations.
804 <term><filename>zoom/zoomtst1</filename>,
805 <filename>zoom/zoomtst2</filename>, ..</term>
807 Several small applications that demonstrates the ZOOM API.
813 If you wish to install &yaz; in system directories
814 <filename>/usr/local/bin</filename>,
815 <filename>/usr/local/lib</filename> .. etc, you can type:
821 You probably need to have root access in order to perform this.
822 You must specify the <literal>--prefix</literal> option for configure if
823 you wish to install &yaz; in other directories than the default
824 <filename>/usr/local/</filename>.
827 If you wish to perform an un-installation of &yaz;, use:
833 This will only work if you haven't reconfigured &yaz; (and therefore
834 changed installation prefix). Note that uninstall will not
835 remove directories created by make install, e.g.
836 <filename>/usr/local/include/yaz</filename>.
839 <sect2 id="installation-linking-yaz-unix">
840 <title>How to make apps using YAZ on UNIX</title>
842 This section describes how to compile - and link your own
843 applications using the &yaz; toolkit.
844 If you're used to Makefiles this shouldn't be hard. As for
845 other libraries you have used before, you need to set a proper include
846 path for your C/C++ compiler and specify the location of
847 &yaz; libraries. You can do it by hand, but generally we suggest
848 you use the <filename>yaz-config</filename> that is generated
849 by <filename>configure</filename>. This is especially
850 important if you're using the threaded version of &yaz; which
851 require you to pass more options to your linker/compiler.
854 The <filename>yaz-config</filename> script accepts command line
855 options that makes the <filename>yaz-config</filename> script print
856 options that you should use in your make process.
857 The most important ones are:
858 <literal>--cflags</literal>, <literal>--libs</literal>
859 which prints C compiler flags, and linker flags respectively.
862 A small and complete <literal>Makefile</literal> for a C
863 application consisting of one source file,
864 <filename>myprog.c</filename>, may look like this:
866 YAZCONFIG=/usr/local/bin/yaz-config
867 CFLAGS=`$(YAZCONFIG) --cflags`
868 LIBS=`$(YAZCONFIG) --libs`
870 $(CC) $(CFLAGS) -o myprog myprog.o $(LIBS)
874 The CFLAGS variable consists of a C compiler directive that will set
875 the include path to the <emphasis>parent</emphasis> directory
876 of <filename>yaz</filename>. That is, if &yaz; header files were
877 installed in <filename>/usr/local/include/yaz</filename>,
878 then include path is set to <filename>/usr/local/include</filename>.
879 Therefore, in your applications you should use
881 #include <yaz/proto.h>
883 and <emphasis>not</emphasis>
885 #include <proto.h>
889 For Libtool users, the <filename>yaz-config</filename> script provides
890 a different variant of option <literal>--libs</literal>, called
891 <literal>--lalibs</literal> that returns the name of the
892 Libtool archive(s) for &yaz; rather than the ordinary ones.
895 For applications using the threaded version of &yaz;,
896 specify <literal>threads</literal> after the
897 other options. When <literal>threads</literal> is given,
898 more flags and linker flags will be printed by
899 <filename>yaz-config</filename>. If our previous example was
900 using threads, you'd have to modify the lines that set
901 <literal>CFLAGS</literal> and <literal>LIBS</literal> as
904 CFLAGS=`$(YAZCONFIG) --cflags threads`
905 LIBS=`$(YAZCONFIG) --libs threads`
907 There is no need specify POSIX thread libraries in your Makefile.
908 The <literal>LIBS</literal> variable includes that as well.
912 <sect1 id="installation.win32">
913 <title>Windows</title>
914 <para>The easiest way to install YAZ on Windows is by downloading
916 <ulink url="&url.yaz.download.win32;">here</ulink>.
917 The installer comes with source too - in case you wish to
918 compile YAZ with different compiler options, etc.
921 <sect2 id="installation.win32.source">
922 <title>Compiling from Source on Windows</title>
924 &yaz; is shipped with "makefiles" for the NMAKE tool that comes
925 with <ulink url="&url.vstudio;">
926 Microsoft Visual Studio</ulink>. It has been tested with
927 Microsoft Visual Studio 2015.
930 Start a command prompt and switch the sub directory
931 <filename>WIN</filename> where the file <filename>makefile</filename>
932 is located. Customize the installation by editing the
933 <filename>makefile</filename> file (for example by using notepad).
934 The following summarizes the most important settings in that file:
937 <term><literal>DEBUG</literal></term>
939 If set to 1, the software is
940 compiled with debugging libraries (code generation is
941 multi-threaded debug DLL).
942 If set to 0, the software is compiled with release libraries
943 (code generation is multi-threaded DLL).
947 <term><literal>HAVE_TCL</literal>, <literal>TCL</literal></term>
949 If <literal>HAVE_TCL</literal> is set to 1, nmake will
950 use the ASN.1 compiler (<ulink url="&url.tcl;">Tcl</ulink> based).
951 You must set <literal>TCL</literal> to the full path of the Tcl
952 interpreter. A Windows version of Tcl is part of
953 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
956 If you do not have Tcl installed, set
957 <literal>HAVE_TCL</literal> to 0.
961 <term><literal>HAVE_BISON</literal>,
962 <literal>BISON</literal></term>
964 If GNU Bison is present, you might set <literal>HAVE_BISON</literal>
965 to 1 and specify the Bison executable in <literal>BISON</literal>.
966 Bison is only required if you use the Git version of
967 YAZ or if you modify the grammar for CQL
968 (<filename>cql.y</filename>).
971 A Windows version of GNU Bison can be fetched from here:
972 <ulink url="http://ftp.indexdata.dk/pub/support/windows/bison-2.4.1-setup.exe"/>.
976 <term><literal>HAVE_ICONV</literal>,
977 <literal>ICONV_DIR</literal></term>
979 If <literal>HAVE_ICONV</literal> is set to 1, YAZ is compiled
980 with iconv support. In this configuration, set
981 <literal>ICONV_DIR</literal> to the iconv source directory.
985 <term><literal>HAVE_LIBXML2</literal>,
986 <literal>LIBXML2_DIR</literal></term>
989 If <literal>HAVE_LIBXML2</literal> is set to 1, YAZ is compiled
990 with SRU support. In this configuration, set
991 <literal>LIBXML2_DIR</literal> to the
992 <ulink url="&url.libxml2;">libxml2</ulink> source directory.
995 You can get pre-compiled Libxml2+Libxslt DLLs and headers from
996 <ulink url="&url.libxml2.download.windows;">here</ulink>.
997 Should you with to compile those libraries yourself, refer to
998 to <xref linkend="installation.windows.libxml2"/>
1003 <term><literal>HAVE_LIBXSLT</literal>,
1004 <literal>LIBXSLT_DIR</literal></term>
1007 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1008 with XSLT support. In this configuration, set
1009 <literal>LIBXSLT_DIR</literal> to the
1010 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1014 libxslt depends on libxml2.
1020 <term><literal>HAVE_ICU</literal>,
1021 <literal>ICU_DIR</literal></term>
1024 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1025 with <ulink url="&url.icu;">ICU</ulink> support.
1026 In this configuration, set
1027 <literal>ICU_DIR</literal> to the
1028 <ulink url="&url.icu;">ICU</ulink> source directory.
1035 When satisfied with the settings in the makefile, type
1042 If the <filename>nmake</filename> command is not found on your system
1043 you probably haven't defined the environment variables required to
1044 use that tool. To fix that, find and run the batch file
1045 <filename>vcvars32.bat</filename>. You need to run it from within
1046 the command prompt or set the environment variables "globally";
1047 otherwise it doesn't work.
1051 If you wish to recompile &yaz; - for example if you modify
1052 settings in the <filename>makefile</filename> you can delete
1053 object files, etc by running.
1059 The following files are generated upon successful compilation:
1062 <term><filename>bin/yaz&soversion;.dll</filename> /
1063 <filename>bin/yaz&soversion;d.dll</filename></term>
1065 &yaz; Release/Debug DLL.
1069 <term><filename>lib/yaz&soversion;.lib</filename> /
1070 <filename>lib/yaz&soversion;d.lib</filename></term>
1072 Import library for <filename>yaz&soversion;.dll</filename> /
1073 <filename>yaz&soversion;d.dll</filename>.
1077 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1078 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1080 Release/Debug DLL for condition variable utilities (condvar.c).
1084 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1085 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1087 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1088 <filename>yaz_cond&soversion;d.dll</filename>.
1092 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1093 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1095 Release/Debug DLL for the ICU wrapper utility.
1096 Only build if HAVE_ICU is 1.
1100 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1101 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1103 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1104 <filename>yaz_icu&soversion;d.dll</filename>.
1108 <term><filename>bin/yaz-ztest.exe</filename></term>
1110 Z39.50 multi-threaded test/example server. It's a WIN32
1111 console application.
1115 <term><filename>bin/yaz-client.exe</filename></term>
1117 &yaz; Z39.50 client application. It's a WIN32 console application.
1118 See chapter <link linkend="yaz-client">YAZ client</link> for more
1123 <term><filename>bin/yaz-icu.exe</filename></term>
1124 <listitem><para>This program exposes the ICU wrapper library if that
1125 is enabled for YAZ. Only if ICU is available this program is
1130 <term><filename>bin/zoomsh.exe</filename></term>
1132 Simple console application implemented on top of the
1133 <link linkend="zoom">ZOOM</link> functions.
1134 The application is a command line shell that allows you to enter
1135 simple commands to perform ZOOM operations.
1139 <term><filename>bin/zoomtst1.exe</filename>,
1140 <filename>bin/zoomtst2.exe</filename>, ..</term>
1142 Several small applications that demonstrate the ZOOM API.
1149 <sect2 id="installation-linking-yaz-win32">
1150 <title>How to make apps using YAZ on Windows</title>
1152 This section will go though the process of linking your Windows
1153 applications with &yaz;.
1156 Some people are confused by the fact that we use the nmake
1157 tool to build &yaz;. They think they have to do that too - in order
1158 to make their Windows applications work with &yaz;. The good news is that
1159 you don't have to. You can use the integrated environment of
1160 Visual Studio if desired for your own application.
1163 When setting up a project or Makefile you have to set the following:
1166 <term>include path</term>
1168 Set it to the <filename>include</filename> directory of &yaz;.
1172 <term>import library <filename>yaz&soversion;.lib</filename></term>
1174 You must link with this library. It's located in the
1175 sub directory <filename>lib</filename> of &yaz;.
1176 If you want to link with the debug version of &yaz;, you must
1177 link against <filename>yaz&soversion;d.lib</filename> instead.
1181 <term>dynamic link library
1182 <filename>yaz&soversion;.dll</filename>
1185 This DLL must be in your execution path when you invoke
1186 your application. Specifically, you should distribute this
1187 DLL with your application.
1194 <sect2 id="installation.windows.libxml2">
1195 <title>Compiling Libxml2 and Libxslt on windows</title>
1197 Download libxml2 and Libxslt source and unpack it.
1198 In the example below we install Libxml2 2.9.2 and Libxslt 1.1.28
1199 for 32-bit, so we use the destination directories
1200 libxml2.2.9.2.win32 and libxslt-1.1.28.win32 to reflect both
1201 version and architecture.
1204 cscript configure.js prefix=c:\libxml2-2.9.2.win32 iconv=no
1211 There's an error in <filename>configure.js</filename> for Libxml2 2.9.2.
1212 Line 17 should be assigned to <filename>configure.ac</filename>
1213 rather than <filename>configure.in</filename>.
1217 For Libxslt it is similar. We must ensure that compilation of
1218 Libxslt links against the already installed libxml2.
1221 cscript configure.js prefix=c:\libxslt-1.1.28.win32 iconv=no \
1222 lib=c:\libxml2-2.9.2.win32\lib \
1223 include=c:\libxml2-2.9.2.win32\include\libxml2
1233 ### Still to document:
1234 ZOOM_connection_errcode(c)
1235 ZOOM_connection_errmsg(c)
1236 ZOOM_connection_addinfo(c)
1237 ZOOM_connection_addinfo(c)
1238 ZOOM_connection_diagset(c);
1239 ZOOM_connection_save_apdu_wrbuf
1240 ZOOM_diag_str(error)
1241 ZOOM_resultset_record_immediate(s, pos)
1242 ZOOM_resultset_cache_reset(r)
1243 ZOOM_options_set_callback(opt, function, handle)
1244 ZOOM_options_create_with_parent2(parent1, parent2)
1245 ZOOM_options_getl(opt, name, len)
1246 ZOOM_options_setl(opt, name, value, len)
1247 ZOOM_options_get_bool(opt, name, defa)
1248 ZOOM_options_get_int(opt, name, defa)
1249 ZOOM_options_set_int(opt, name, value)
1254 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1255 an initiative started by Mike Taylor (Mike is from the UK, which
1256 explains the peculiar name of the model). The goal of &zoom; is to
1257 provide a common Z39.50 client API not bound to a particular
1258 programming language or toolkit.
1261 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1262 You can make SRU ZOOM connections by specifying scheme
1263 <literal>http://</literal> for the hostname for a connection.
1264 The dialect of SRU used is specified by the value of the
1265 connection's <literal>sru</literal> option, which may be SRU over
1266 HTTP GET (<literal>get</literal>),
1267 SRU over HTTP POST (<literal>post</literal>), (SRU over
1268 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1269 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1270 Using the facility for embedding options in target strings, a
1271 connection can be forced to use SRU rather the SRW (the default) by
1272 prefixing the target string with <literal>sru=get,</literal>, like this:
1273 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1276 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1277 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1278 HTTP based protocols.
1281 The lack of a simple Z39.50 client API for &yaz; has become more
1282 and more apparent over time. So when the first &zoom; specification
1284 an implementation for &yaz; was quickly developed. For the first time, it is
1285 now as easy (or easier!) to develop clients as it is to develop
1286 servers with &yaz;. This
1287 chapter describes the &zoom; C binding. Before going further, please
1288 reconsider whether C is the right programming language for the job.
1289 There are other language bindings available for &yaz;, and still
1291 are in active development. See the
1292 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1296 In order to fully understand this chapter you should read and
1297 try the example programs <literal>zoomtst1.c</literal>,
1298 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1302 The C language misses features found in object oriented languages
1303 such as C++, Java, etc. For example, you'll have to manually,
1304 destroy all objects you create, even though you may think of them as
1305 temporary. Most objects have a <literal>_create</literal> - and a
1306 <literal>_destroy</literal> variant.
1307 All objects are in fact pointers to internal stuff, but you don't see
1308 that because of typedefs. All destroy methods should gracefully ignore a
1309 <literal>NULL</literal> pointer.
1312 In each of the sections below you'll find a sub section called
1313 protocol behavior, that describes how the API maps to the Z39.50
1316 <sect1 id="zoom-connections">
1317 <title>Connections</title>
1318 <para>The Connection object is a session with a target.
1321 #include <yaz/zoom.h>
1323 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1325 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1327 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1329 void ZOOM_connection_destroy(ZOOM_connection c);
1332 Connection objects are created with either function
1333 <function>ZOOM_connection_new</function> or
1334 <function>ZOOM_connection_create</function>.
1335 The former creates and automatically attempts to establish a network
1336 connection with the target. The latter doesn't establish
1337 a connection immediately, thus allowing you to specify options
1338 before establishing network connection using the function
1339 <function>ZOOM_connection_connect</function>.
1340 If the port number, <literal>portnum</literal>, is zero, the
1341 <literal>host</literal> is consulted for a port specification.
1342 If no port is given, 210 is used. A colon denotes the beginning of
1343 a port number in the host string. If the host string includes a
1344 slash, the following part specifies a database for the connection.
1347 You can prefix the host with a scheme followed by colon. The
1348 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1349 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1350 but can overridden to use SRU/post, SRW, and the Solr protocol.
1353 You can prefix the scheme-qualified host-string with one or more
1355 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1356 sequences, each of which represents an option to be set into the
1357 connection structure <emphasis>before</emphasis> the
1358 protocol-level connection is forged and the initialization
1359 handshake takes place. This facility can be used to provide
1360 authentication credentials, as in host-strings such as:
1361 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1364 Connection objects should be destroyed using the function
1365 <function>ZOOM_connection_destroy</function>.
1368 void ZOOM_connection_option_set(ZOOM_connection c,
1369 const char *key, const char *val);
1371 void ZOOM_connection_option_setl(ZOOM_connection c,
1373 const char *val, int len);
1375 const char *ZOOM_connection_option_get(ZOOM_connection c,
1377 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1382 The functions <function>ZOOM_connection_option_set</function> and
1383 <function>ZOOM_connection_option_setl</function> allows you to
1384 set an option given by <parameter>key</parameter> to the value
1385 <parameter>value</parameter> for the connection.
1386 For <function>ZOOM_connection_option_set</function>, the
1387 value is assumed to be a 0-terminated string. Function
1388 <function>ZOOM_connection_option_setl</function> specifies a
1389 value of a certain size (len).
1392 Functions <function>ZOOM_connection_option_get</function> and
1393 <function>ZOOM_connection_option_getl</function> returns
1394 the value for an option given by <parameter>key</parameter>.
1396 <table id="zoom-connection-options" frame="top">
1397 <title>ZOOM Connection Options</title>
1399 <colspec colwidth="4*" colname="name"></colspec>
1400 <colspec colwidth="7*" colname="description"></colspec>
1401 <colspec colwidth="3*" colname="default"></colspec>
1404 <entry>Option</entry>
1405 <entry>Description</entry>
1406 <entry>Default</entry>
1411 implementationName</entry><entry>Name of Your client
1412 </entry><entry>none</entry></row>
1414 user</entry><entry>Authentication user name
1415 </entry><entry>none</entry></row>
1417 group</entry><entry>Authentication group name
1418 </entry><entry>none</entry></row>
1420 password</entry><entry>Authentication password.
1421 </entry><entry>none</entry></row>
1423 authenticationMode</entry><entry>How authentication is encoded.
1424 </entry><entry>basic</entry></row>
1426 host</entry><entry>Target host. This setting is "read-only".
1427 It's automatically set internally when connecting to a target.
1428 </entry><entry>none</entry></row>
1430 proxy</entry><entry>Proxy host. If set, the logical host
1431 is encoded in the otherInfo area of the Z39.50 Init PDU
1432 with OID 1.2.840.10003.10.1000.81.1.
1433 </entry><entry>none</entry></row>
1435 clientIP</entry><entry>Client IP. If set, is
1436 encoded in the otherInfo area of a Z39.50 PDU with OID
1437 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1438 of a client. Is used if ZOOM is used in a gateway of some sort.
1439 </entry><entry>none</entry></row>
1441 async</entry><entry>If true (1) the connection operates in
1442 asynchronous operation which means that all calls are non-blocking
1444 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1445 </entry><entry>0</entry></row>
1447 maximumRecordSize</entry><entry> Maximum size of single record.
1448 </entry><entry>1 MB</entry></row>
1450 preferredMessageSize</entry><entry> Maximum size of multiple records.
1451 </entry><entry>1 MB</entry></row>
1453 lang</entry><entry> Language for negotiation.
1454 </entry><entry>none</entry></row>
1456 charset</entry><entry> Character set for negotiation.
1457 </entry><entry>none</entry></row>
1459 serverImplementationId</entry><entry>
1460 Implementation ID of server. (The old targetImplementationId
1461 option is also supported for the benefit of old applications.)
1462 </entry><entry>none</entry></row>
1464 targetImplementationName</entry><entry>
1465 Implementation Name of server. (The old
1466 targetImplementationName option is also supported for the
1467 benefit of old applications.)
1468 </entry><entry>none</entry></row>
1470 serverImplementationVersion</entry><entry>
1471 Implementation Version of server. (the old
1472 targetImplementationVersion option is also supported for the
1473 benefit of old applications.)
1474 </entry><entry>none</entry></row>
1476 databaseName</entry><entry>One or more database names
1477 separated by character plus (<literal>+</literal>), which is to
1478 be used by subsequent search requests on this Connection.
1479 </entry><entry>Default</entry></row>
1481 piggyback</entry><entry>True (1) if piggyback should be
1482 used in searches; false (0) if not.
1483 </entry><entry>1</entry></row>
1485 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1486 value, then target will return all records using small element set name
1487 </entry><entry>0</entry></row>
1489 largeSetLowerBound</entry><entry>If hits is greater than this
1490 value, the target will return no records.
1491 </entry><entry>1</entry></row>
1493 mediumSetPresentNumber</entry><entry>This value represents
1494 the number of records to be returned as part of a search when
1495 hits is less than or equal to large set lower bound and if hits
1496 is greater than small set upper bound.
1497 </entry><entry>0</entry></row>
1499 smallSetElementSetName</entry><entry>
1500 The element set name to be used for small result sets.
1501 </entry><entry>none</entry></row>
1503 mediumSetElementSetName</entry><entry>
1504 The element set name to be used for medium-sized result sets.
1505 </entry><entry>none</entry></row>
1507 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1508 After a successful Init, these options may be interrogated to
1509 discover whether the server claims to support the specified
1511 </entry><entry>none</entry></row>
1513 <entry>sru</entry><entry>
1514 SRU/Solr transport type. Must be either <literal>soap</literal>,
1515 <literal>get</literal>, <literal>post</literal>, or
1516 <literal>solr</literal>.
1517 </entry><entry>soap</entry></row>
1519 sru_version</entry><entry>
1520 SRU/SRW version. Should be <literal>1.1</literal>, or
1521 <literal>1.2</literal>. This is, prior to connect, the version
1522 to offer (highest version). And following connect (in fact
1523 first operation), holds the negotiated version with the server
1524 (same or lower version).
1525 </entry><entry>1.2</entry></row>
1526 <row id="zoom.extraArgs.option"><entry>
1527 extraArgs</entry><entry>
1528 Extra arguments for SRU/Solr URLs. The value must be
1529 URL encoded already.
1530 </entry><entry></entry></row>
1531 <row id="zoom.facets.option"><entry>
1532 facets</entry><entry>
1533 Requested or recommended facets may be given before a search is sent.
1534 The value of this setting is described in <xref linkend="facets"/>
1535 For inspection of the facets returned, refer to the functions
1536 described in <xref linkend="zoom.facets"/>.
1537 </entry><entry>none</entry></row>
1539 apdulog</entry><entry>
1540 If set to a true value such as "1", a log of low-level
1541 protocol packets is emitted on standard error stream. This
1542 can be very useful for debugging.
1543 </entry><entry>0</entry></row>
1545 saveAPDU</entry><entry>
1546 If set to a true value such as "1", a log of low-level
1547 protocol packets is saved. The log can be retrieved by reading
1548 option APDU. Setting saveAPDU always has the side effect of
1549 resetting the currently saved log. This setting is
1550 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1551 It is only recognized in
1552 <function>ZOOM_connection_option_set</function>.
1553 </entry><entry>0</entry></row>
1556 Returns the log of protocol packets. Will be empty if logging
1557 is not enabled (see saveAPDU above). This setting is
1558 <emphasis>read-only</emphasis>. It is only recognized if used
1559 in call to <function>ZOOM_connection_option_get</function> or
1560 <function>ZOOM_connection_option_getl</function>.
1561 </entry><entry></entry></row>
1563 memcached</entry><entry>
1564 If given and non-empty,
1565 <ulink url="&url.libmemcached;">libMemcached</ulink>
1566 will be configured for the connection.
1567 This option is inspected by ZOOM when a connection is established.
1568 If the <literal>memcached</literal> option is given
1569 and YAZ is compiled without libMemcached support, an internal
1570 diagnostic (10018) will be thrown.
1571 libMemcached support is available for YAZ 5.0.13 or later. If this
1572 option is supplied for an earlier version of YAZ, it is
1573 <emphasis>ignored</emphasis>.
1574 The value of this option is a list options - each is of the
1575 form <literal>--name=value</literal>.
1576 Option <literal>--server=</literal>host[:port] specifies a memcached
1577 server. It may be repeated for multiple memcached servers.
1578 Option <literal>--expire=</literal>seconds sets expiry time in seconds
1579 for how long result sets are to be cached.
1580 </entry><entry>none</entry></row>
1582 redis</entry><entry>
1583 If given and non-empty,
1584 a <ulink url="&url.redis;">redis</ulink> context will be created
1586 This option is inspected by ZOOM when a connection is established.
1587 If the <literal>redis</literal> option is given
1588 and YAZ is compiled without redis support, an internal
1589 diagnostic (10018) will be thrown.
1590 redis support is available for YAZ 5.2.0 or later. If this
1591 option is supplied for an earlier version of YAZ, it is
1592 <emphasis>ignored</emphasis>.
1593 The value of this option is a set of options, similar to that
1594 of the memcached setting. At this stage only --server=host[:port]
1595 and --expire=seconds are supported.
1596 </entry><entry>none</entry></row>
1601 If either option <literal>lang</literal> or <literal>charset</literal>
1603 <ulink url="&url.z39.50.charneg;">
1604 Character Set and Language Negotiation</ulink> is in effect.
1607 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1608 const char **addinfo);
1609 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1610 const char **addinfo, const char **dset);
1613 Function <function>ZOOM_connection_error</function> checks for
1614 errors for the last operation(s) performed. The function returns
1615 zero if no errors occurred; non-zero otherwise indicating the error.
1616 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1617 holds messages for the error and additional-info if passed as
1618 non-<literal>NULL</literal>. Function
1619 <function>ZOOM_connection_error_x</function> is an extended version
1620 of <function>ZOOM_connection_error</function> that is capable of
1621 returning name of diagnostic set in <parameter>dset</parameter>.
1623 <sect2 id="zoom-connection-z39.50">
1624 <title>Z39.50 Protocol behavior</title>
1626 The calls <function>ZOOM_connection_new</function> and
1627 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1628 connection and sends an Initialize Request to the target if
1629 possible. In addition, the calls wait for an Initialize Response
1630 from the target and the result is inspected (OK or rejected).
1633 If <literal>proxy</literal> is set then the client will establish
1634 a TCP/IP connection with the peer as specified by the
1635 <literal>proxy</literal> host and the hostname as part of the
1636 connect calls will be set as part of the Initialize Request.
1637 The proxy server will then "forward" the PDU's transparently
1638 to the target behind the proxy.
1641 For the authentication parameters, if option <literal>user</literal>
1642 is set and both options <literal>group</literal> and
1643 <literal>pass</literal> are unset, then Open style
1644 authentication is used (Version 2/3) in which case the username
1645 is usually followed by a slash, then by a password.
1646 If either <literal>group</literal>
1647 or <literal>pass</literal> is set then idPass authentication
1648 (Version 3 only) is used. If none of the options are set, no
1649 authentication parameters are set as part of the Initialize Request
1653 When option <literal>async</literal> is 1, it really means that
1654 all network operations are postponed (and queued) until the
1655 function <literal>ZOOM_event</literal> is invoked. When doing so
1656 it doesn't make sense to check for errors after
1657 <literal>ZOOM_connection_new</literal> is called since that
1658 operation "connecting - and init" is still incomplete and the
1659 API cannot tell the outcome (yet).
1662 <sect2 id="zoom.sru.init.behavior">
1663 <title>SRU/Solr Protocol behavior</title>
1665 The HTTP based protocols (SRU, SRW, Solr) do not feature an
1666 Inititialize Request, so the connection phase merely establishes a
1667 TCP/IP connection with the HTTP server.
1669 <para>Most of the ZOOM connection options do not
1670 affect SRU/Solr and they are ignored. However, future versions
1671 of &yaz; might honor <literal>implementationName</literal> and
1672 put that as part of User-Agent header for HTTP requests.
1675 The <literal>charset</literal> is used in the Content-Type header
1679 Setting <literal>authentcationMode</literal> specifies how
1680 authentication parameters are encoded for HTTP. The default is
1681 "<literal>basic</literal>" where <literal>user</literal> and
1682 <literal>password</literal> are encoded by using HTTP basic
1686 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1687 user and password are encoded in the URL by parameters
1688 <literal>x-username</literal> and <literal>x-password</literal> as
1689 given by the SRU standard.
1693 <sect1 id="zoom.query">
1694 <title>Queries</title>
1696 Query objects represents queries.
1699 ZOOM_query ZOOM_query_create(void);
1701 void ZOOM_query_destroy(ZOOM_query q);
1703 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1705 int ZOOM_query_cql(ZOOM_query s, const char *str);
1707 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1709 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1710 const char *criteria);
1713 Create query objects using <function>ZOOM_query_create</function>
1714 and destroy them by calling <function>ZOOM_query_destroy</function>.
1715 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1716 notation by using the
1717 function <function>ZOOM_query_prefix</function>.
1718 The <function>ZOOM_query_cql</function> specifies a CQL
1719 query to be sent to the server/target.
1720 More query types will be added in future versions of &yaz;, such as
1721 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1722 etc. In addition to a search, a sort criteria may be set. Function
1723 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1724 it takes sort criteria using the same string notation as
1725 yaz-client's <link linkend="sortspec">sort command</link>.
1727 <para id="zoom.query.sortby2">
1728 <function>ZOOM_query_sortby2</function> is similar to
1729 <function>ZOOM_query_sortby</function> but allows a strategy for
1730 sorting. The reason for the strategy parameter is that some
1731 protocols offer multiple ways of performing sorting.
1732 For example, Z39.50 has the standard sort, which is performed after
1733 search on an existing result set.
1734 It's also possible to use CQL in Z39.50 as the query type and use
1735 CQL's SORTBY keyword. Finally, Index Data's
1736 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1738 <table id="zoom-sort-strategy" frame="top">
1739 <title>ZOOM sort strategy</title>
1741 <colspec colwidth="2*" colname="name"/>
1742 <colspec colwidth="5*" colname="description"/>
1746 <entry>Description</entry>
1751 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1754 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1757 <entry>cql</entry><entry>CQL SORTBY</entry>
1760 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1763 <entry>solr</entry><entry>Solr sort</entry>
1766 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1767 solr for Solr protocol</entry>
1773 <sect1 id="zoom.resultsets"><title>Result sets</title>
1775 The result set object is a container for records returned from
1779 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1781 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1783 void ZOOM_resultset_destroy(ZOOM_resultset r);
1786 Function <function>ZOOM_connection_search</function> creates
1787 a result set, given a connection and query.
1788 Destroy a result set by calling
1789 <function>ZOOM_resultset_destroy</function>.
1790 Simple clients using PQF only, may use the function
1791 <function>ZOOM_connection_search_pqf</function> in which case
1792 creating query objects is not necessary.
1795 void ZOOM_resultset_option_set(ZOOM_resultset r,
1796 const char *key, const char *val);
1798 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1800 size_t ZOOM_resultset_size(ZOOM_resultset r);
1803 Functions <function>ZOOM_resultset_options_set</function> and
1804 <function>ZOOM_resultset_get</function> sets and gets an option
1805 for a result set similar to <function>ZOOM_connection_option_get</function>
1806 and <function>ZOOM_connection_option_set</function>.
1809 The number of hits, also called result-count, is returned by
1810 function <function>ZOOM_resultset_size</function>.
1812 <table id="zoom.resultset.options"
1813 frame="top"><title>ZOOM Result set Options</title>
1815 <colspec colwidth="4*" colname="name"></colspec>
1816 <colspec colwidth="7*" colname="description"></colspec>
1817 <colspec colwidth="2*" colname="default"></colspec>
1820 <entry>Option</entry>
1821 <entry>Description</entry>
1822 <entry>Default</entry>
1827 start</entry><entry>Offset of first record to be
1828 retrieved from target. First record has offset 0 unlike the
1829 protocol specifications where first record has position 1.
1830 This option affects ZOOM_resultset_search and
1831 ZOOM_resultset_search_pqf and must be set before any of
1832 these functions are invoked. If a range of
1833 records must be fetched manually after search,
1834 function ZOOM_resultset_records should be used.
1835 </entry><entry>0</entry></row>
1837 count</entry><entry>Number of records to be retrieved.
1838 This option affects ZOOM_resultset_search and
1839 ZOOM_resultset_search_pqf and must be set before any of
1840 these functions are invoked.
1841 </entry><entry>0</entry></row>
1843 presentChunk</entry><entry>The number of records to be
1844 requested from the server in each chunk (present request). The
1845 value 0 means to request all the records in a single chunk.
1846 (The old <literal>step</literal>
1847 option is also supported for the benefit of old applications.)
1848 </entry><entry>0</entry></row>
1850 elementSetName</entry><entry>Element-Set name of records.
1851 Most targets should honor element set name <literal>B</literal>
1852 and <literal>F</literal> for brief and full respectively.
1853 </entry><entry>none</entry></row>
1855 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1856 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1857 </entry><entry>none</entry></row>
1859 schema</entry><entry>Schema for retrieval, such as
1860 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1861 </entry><entry>none</entry></row>
1863 setname</entry><entry>Name of Result Set (Result Set ID).
1864 If this option isn't set, the ZOOM module will automatically
1865 allocate a result set name.
1866 </entry><entry>default</entry></row>
1868 rpnCharset</entry><entry>Character set for RPN terms.
1869 If this is set, ZOOM C will assume that the ZOOM application is
1870 running UTF-8. Terms in RPN queries are then converted to the
1871 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1872 of RPN terms and no conversion is performed.
1873 </entry><entry>none</entry></row>
1878 For servers that support Search Info report, the following
1879 options may be read using <function>ZOOM_resultset_get</function>.
1880 This detailed information is read after a successful search has
1884 This information is a list of of items, where each item is
1885 information about a term or subquery. All items in the list
1887 <literal>SearchResult.</literal><replaceable>no</replaceable>
1888 where no presents the item number (0=first, 1=second).
1889 Read <literal>searchresult.size</literal> to determine the
1892 <table id="zoom.search.info.report.options"
1893 frame="top"><title>Search Info Report Options</title>
1895 <colspec colwidth="4*" colname="name"></colspec>
1896 <colspec colwidth="7*" colname="description"></colspec>
1899 <entry>Option</entry>
1900 <entry>Description</entry>
1905 <entry>searchresult.size</entry>
1907 number of search result entries. This option is non-existent
1908 if no entries are returned by the server.
1912 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1913 <entry>sub query ID</entry>
1916 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1917 <entry>result count for item (number of hits)</entry>
1920 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1921 <entry>subquery term</entry>
1925 searchresult.<replaceable>no</replaceable>.interpretation.term
1927 <entry>interpretation term</entry>
1931 searchresult.<replaceable>no</replaceable>.recommendation.term
1933 <entry>recommendation term</entry>
1938 <sect2 id="zoom.z3950.resultset.sort">
1939 <title>Z39.50 Result-set Sort</title>
1941 void ZOOM_resultset_sort(ZOOM_resultset r,
1942 const char *sort_type, const char *sort_spec);
1944 int ZOOM_resultset_sort1(ZOOM_resultset r,
1945 const char *sort_type, const char *sort_spec);
1948 <function>ZOOM_resultset_sort</function> and
1949 <function>ZOOM_resultset_sort1</function> both sort an existing
1950 result-set. The sort_type parameter is not used. Set it to "yaz".
1951 The sort_spec is same notation as ZOOM_query_sortby and identical
1952 to that offered by yaz-client's
1953 <link linkend="sortspec">sort command</link>.
1956 These functions only work for Z39.50. Use the more generic utility
1957 <link linkend="zoom.query.sortby2">
1958 <function>ZOOM_query_sortby2</function></link>
1959 for other protocols (and even Z39.50).
1962 <sect2 id="zoom.z3950.resultset.behavior">
1963 <title>Z39.50 Protocol behavior</title>
1965 The creation of a result set involves at least a SearchRequest
1966 - SearchResponse protocol handshake. Following that, if a sort
1967 criteria was specified as part of the query, a SortRequest -
1968 SortResponse handshake takes place. Note that it is necessary to
1969 perform sorting before any retrieval takes place, so no records will
1970 be returned from the target as part of the SearchResponse because these
1971 would be unsorted. Hence, piggyback is disabled when sort criteria
1972 are set. Following Search - and a possible sort - Retrieval takes
1973 place - as one or more Present Requests/Response pairs being
1977 The API allows for two different modes for retrieval. A high level
1978 mode which is somewhat more powerful and a low level one.
1979 The low level is enabled when searching on a Connection object
1980 for which the settings
1981 <literal>smallSetUpperBound</literal>,
1982 <literal>mediumSetPresentNumber</literal> and
1983 <literal>largeSetLowerBound</literal> are set. The low level mode
1984 thus allows you to precisely set how records are returned as part
1985 of a search response as offered by the Z39.50 protocol.
1986 Since the client may be retrieving records as part of the
1987 search response, this mode doesn't work well if sorting is used.
1990 The high-level mode allows you to fetch a range of records from
1991 the result set with a given start offset. When you use this mode
1992 the client will automatically use piggyback if that is possible
1993 with the target, and perform one or more present requests as needed.
1994 Even if the target returns fewer records as part of a present response
1995 because of a record size limit, etc. the client will repeat sending
1996 present requests. As an example, if option <literal>start</literal>
1997 is 0 (default) and <literal>count</literal> is 4, and
1998 <literal>piggyback</literal> is 1 (default) and no sorting criteria
1999 is specified, then the client will attempt to retrieve the 4
2000 records as part the search response (using piggyback). On the other
2001 hand, if either <literal>start</literal> is positive or if
2002 a sorting criteria is set, or if <literal>piggyback</literal>
2003 is 0, then the client will not perform piggyback but send Present
2007 If either of the options <literal>mediumSetElementSetName</literal> and
2008 <literal>smallSetElementSetName</literal> are unset, the value
2009 of option <literal>elementSetName</literal> is used for piggyback
2010 searches. This means that for the high-level mode you only have
2011 to specify one elementSetName option rather than three.
2014 <sect2 id="zoom.sru.resultset.behavior">
2015 <title>SRU Protocol behavior</title>
2017 Current version of &yaz; does not take advantage of a result set id
2018 returned by the SRU server. Future versions might do, however.
2019 Since the ZOOM driver does not save result set IDs, any
2020 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2021 with same query but, possibly, different offsets.
2024 Option <literal>schema</literal> specifies SRU schema
2025 for retrieval. However, options <literal>elementSetName</literal> and
2026 <literal>preferredRecordSyntax</literal> are ignored.
2029 Options <literal>start</literal> and <literal>count</literal>
2030 are supported by SRU.
2031 The remaining options
2032 <literal>piggyback</literal>,
2033 <literal>smallSetUpperBound</literal>,
2034 <literal>largeSetLowerBound</literal>,
2035 <literal>mediumSetPresentNumber</literal>,
2036 <literal>mediumSetElementSetName</literal>,
2037 <literal>smallSetElementSetName</literal> are
2041 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2042 If PQF is used, however, the PQF query is transferred anyway
2043 using non-standard element <literal>pQuery</literal> in
2044 SRU SearchRetrieveRequest.
2047 Solr queries need to be done in Solr query format.
2050 Unfortunately, SRU and Solr do not define a database setting. Hence,
2051 <literal>databaseName</literal> is unsupported and ignored.
2052 However, the path part in host parameter for functions
2053 <function>ZOOM_connecton_new</function> and
2054 <function>ZOOM_connection_connect</function> acts as a
2055 database (at least for the &yaz; SRU server).
2059 <sect1 id="zoom.records">
2060 <title>Records</title>
2062 A record object is a retrieval record on the client side -
2063 created from result sets.
2066 void ZOOM_resultset_records(ZOOM_resultset r,
2068 size_t start, size_t count);
2069 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2071 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2074 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2075 const char **addinfo, const char **diagset);
2077 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2079 void ZOOM_record_destroy(ZOOM_record rec);
2082 References to temporary records are returned by functions
2083 <function>ZOOM_resultset_records</function> or
2084 <function>ZOOM_resultset_record</function>.
2087 If a persistent reference to a record is desired
2088 <function>ZOOM_record_clone</function> should be used.
2089 It returns a record reference that should be destroyed
2090 by a call to <function>ZOOM_record_destroy</function>.
2093 A single record is returned by function
2094 <function>ZOOM_resultset_record</function> that takes a
2095 position as argument. First record has position zero.
2096 If no record could be obtained <literal>NULL</literal> is returned.
2099 Error information for a record can be checked with
2100 <function>ZOOM_record_error</function> which returns non-zero
2101 (error code) if record is in error, called <emphasis>Surrogate
2102 Diagnostics</emphasis> in Z39.50.
2105 Function <function>ZOOM_resultset_records</function> retrieves
2106 a number of records from a result set. Parameter <literal>start</literal>
2107 and <literal>count</literal> specifies the range of records to
2108 be returned. Upon completion, the array
2109 <literal>recs[0], ..recs[count-1]</literal>
2110 holds record objects for the records. The array of records
2111 <literal>recs</literal> should be allocated prior the call
2112 <function>ZOOM_resultset_records</function>. Note that for those
2113 records that couldn't be retrieved from the target,
2114 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2116 <para id="zoom.record.get">
2117 In order to extract information about a single record,
2118 <function>ZOOM_record_get</function> is provided. The
2119 function returns a pointer to certain record information. The
2120 nature (type) of the pointer depends on the parameter,
2121 <parameter>type</parameter>.
2124 The <parameter>type</parameter> is a string of the format:
2127 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>][;base64=<replaceable>xpath</replaceable>]
2130 If <literal>charset</literal> is given, then <replaceable>from</replaceable>
2131 specifies the character set of the record in its original form
2132 (as returned by the server), <replaceable>to</replaceable> specifies
2133 the output (returned) character set encoding.
2134 If <replaceable>to</replaceable> is omitted, then UTF-8 is assumed.
2135 If charset is not given, then no character set conversion takes place.
2136 OPAC records may be returned in a different
2137 set from the bibliographic MARC record. If this is this the case,
2138 <replaceable>opacfrom</replaceable> should be set to the character set
2139 of the OPAC record part.
2143 The <literal>format</literal> is generic but can only be used to
2144 specify XML indentation when the value <replaceable>v</replaceable>
2145 is 1 (<literal>format=1</literal>).
2148 The <literal>base64</literal> allows a full record to be extracted
2149 from base64-encoded string in an XML document.
2153 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2156 Specifying the base64 parameter requires YAZ 4.2.35 or later.
2160 The format argument controls whether record data should be XML
2161 pretty-printed (post process operation).
2162 It is enabled only if format value <replaceable>v</replaceable> is
2163 <literal>1</literal> and the record content is XML well-formed.
2166 In addition, for certain types, the length
2167 <literal>len</literal> passed will be set to the size in bytes of
2168 the returned information.
2171 The following are the supported values for <replaceable>form</replaceable>.
2173 <varlistentry><term><literal>database</literal></term>
2174 <listitem><para>The Database of the record is returned
2175 as a C null-terminated string. Return type
2176 <literal>const char *</literal>.
2179 <varlistentry><term><literal>syntax</literal></term>
2180 <listitem><para>The transfer syntax of the record is returned
2181 as a C null-terminated string containing the symbolic name of
2182 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2184 <literal>const char *</literal>.
2187 <varlistentry><term><literal>schema</literal></term>
2188 <listitem><para>The schema of the record is returned
2189 as a C null-terminated string. Return type is
2190 <literal>const char *</literal>.
2193 <varlistentry><term><literal>render</literal></term>
2194 <listitem><para>The record is returned in a display friendly
2195 format. Upon completion, buffer is returned
2196 (type <literal>const char *</literal>) and length is stored in
2197 <literal>*len</literal>.
2200 <varlistentry><term><literal>raw</literal></term>
2201 <listitem><para>The record is returned in the internal
2202 YAZ specific format. For GRS-1, Explain, and others, the
2203 raw data is returned as type
2204 <literal>Z_External *</literal> which is just the type for
2205 the member <literal>retrievalRecord</literal> in
2206 type <literal>NamePlusRecord</literal>.
2207 For SUTRS and octet aligned record (including all MARCs) the
2208 octet buffer is returned and the length of the buffer.
2211 <varlistentry><term><literal>xml</literal></term>
2212 <listitem><para>The record is returned in XML if possible.
2213 SRU, Solr and Z39.50 records with transfer syntax XML are
2214 returned verbatim. MARC records are returned in
2215 <ulink url="&url.marcxml;">
2218 (converted from ISO2709 to MARCXML by YAZ).
2219 OPAC records are also converted to XML and the
2220 bibliographic record is converted to MARCXML (when possible).
2221 GRS-1 records are not supported for this form.
2222 Upon completion, the XML buffer is returned
2223 (type <literal>const char *</literal>) and length is stored in
2224 <literal>*len</literal>.
2227 <varlistentry><term><literal>opac</literal></term>
2228 <listitem><para>OPAC information for record is returned in XML
2229 if an OPAC record is present at the position given. If no
2230 OPAC record is present, a NULL pointer is returned.
2233 <varlistentry><term><literal>txml</literal></term>
2234 <listitem><para>The record is returned in TurboMARC if possible.
2235 SRU and Z39.50 records with transfer syntax XML are
2236 returned verbatim. MARC records are returned in
2237 <link linkend="tools.turbomarc">
2240 (converted from ISO2709 to TurboMARC by YAZ).
2241 Upon completion, the XML buffer is returned
2242 (type <literal>const char *</literal>) and length is stored in
2243 <literal>*len</literal>.
2246 <varlistentry><term><literal>json</literal></term>
2247 <listitem><para>Like xml, but MARC records are converted to
2248 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2256 <ulink url="&url.marc21;">MARC21</ulink>
2258 <ulink url="&url.marc8;">MARC-8</ulink>
2259 character set encoding.
2260 An application that wishes to display in Latin-1 would use
2262 render; charset=marc8,iso-8859-1
2265 <sect2 id="zoom.z3950.record.behavior">
2266 <title>Z39.50 Protocol behavior</title>
2268 The functions <function>ZOOM_resultset_record</function> and
2269 <function>ZOOM_resultset_records</function> inspects the client-side
2270 record cache. Records not found in cache are fetched using
2272 The functions may block (and perform network I/O) - even though option
2273 <literal>async</literal> is 1, because they return records objects.
2274 (And there's no way to return records objects without retrieving them!)
2277 There is a trick, however, in the usage of function
2278 <function>ZOOM_resultset_records</function> that allows for
2279 delayed retrieval (and makes it non-blocking). By using
2280 a null pointer for <parameter>recs</parameter> you're indicating
2281 you're not interested in getting records objects
2282 <emphasis>now</emphasis>.
2285 <sect2 id="zoom.sru.record.behavior">
2286 <title>SRU/Solr Protocol behavior</title>
2288 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2289 as if they where Z39.50 records with transfer syntax XML and
2290 no element set name or database name.
2294 <sect1 id="zoom.facets"><title>Facets</title>
2296 Facet operations is not part of the official ZOOM specification, but
2297 is an Index Data extension for YAZ-based Z39.50 targets,
2298 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2300 Facets may be requestd by the
2301 <link linkend="zoom.facets.option">facets</link> option before a
2303 For inspection of the returned facets, the following functions are
2307 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2309 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2310 const char *facet_name);
2312 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2315 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2317 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2319 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2321 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2322 size_t idx, int *freq);
2325 References to temporary structures are returned by all functions.
2326 They are only valid as long the Result set is valid.
2327 <function>ZOOM_resultset_get_facet_field</function> or
2328 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2329 <function>ZOOM_resultset_facets</function>.
2330 <function>ZOOM_facet_field_name</function>.
2331 <function>ZOOM_facet_field_get_term</function>.
2333 <para id="zoom.resultset.get_facet_field">
2334 A single Facet field is returned by function
2335 <function>ZOOM_resultset_get_facet_field</function> or
2336 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2337 a result set and facet name or positive index respectively. First
2338 facet has position zero. If no facet could be obtained (invalid name
2339 or index out of bounds) <literal>NULL</literal> is returned.
2341 <para id="zoom.resultset.facets">
2342 An array of facets field can be returned by
2343 <function>ZOOM_resultset_facets</function>. The length of the array is
2344 given by <function>ZOOM_resultset_facets_size</function>. The array is
2345 zero-based and the last entry will be at
2346 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2348 <para id="zoom.resultset.facets_names">
2349 It is possible to interate over facets by name, by calling
2350 <function>ZOOM_resultset_facets_names</function>.
2351 This will return a const array of char * where each string can be used
2352 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2355 Function <function>ZOOM_facet_field_name</function> gets the request
2356 facet name from a returned facet field.
2359 Function <function>ZOOM_facet_field_get_term</function> returns the
2360 idx'th term and term count for a facet field.
2361 Idx must between 0 and
2362 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2363 returned reference will be <literal>NULL</literal>. On a valid idx, the
2364 value of the freq reference will be the term count.
2365 The <literal>freq</literal> parameter must be valid pointer to integer.
2368 <sect1 id="zoom.scan"><title>Scan</title>
2370 This section describes an interface for Scan. Scan is not an
2371 official part of the ZOOM model yet. The result of a scan operation
2372 is the <literal>ZOOM_scanset</literal> which is a set of terms
2373 returned by a target.
2377 The Scan interface is supported for both Z39.50, SRU and Solr.
2381 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2382 const char *startpqf);
2384 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2387 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2389 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2390 size_t *occ, size_t *len);
2392 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2393 size_t *occ, size_t *len);
2395 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2397 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2400 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2404 The scan set is created by function
2405 <function>ZOOM_connection_scan</function> which performs a scan
2406 operation on the connection using the specified
2407 <parameter>startpqf</parameter>.
2408 If the operation was successful, the size of the scan set can be
2409 retrieved by a call to <function>ZOOM_scanset_size</function>.
2410 Like result sets, the items are numbered 0..size-1.
2411 To obtain information about a particular scan term, call function
2412 <function>ZOOM_scanset_term</function>. This function takes
2413 a scan set offset <literal>pos</literal> and returns a pointer
2414 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2416 If present, the <literal>occ</literal> and <literal>len</literal>
2417 are set to the number of occurrences and the length
2418 of the actual term respectively.
2419 <function>ZOOM_scanset_display_term</function> is similar to
2420 <function>ZOOM_scanset_term</function> except that it returns
2421 the <emphasis>display term</emphasis> rather than the raw term.
2422 In a few cases, the term is different from display term. Always
2423 use the display term for display and the raw term for subsequent
2424 scan operations (to get more terms, next scan result, etc).
2427 A scan set may be freed by a call to function
2428 <function>ZOOM_scanset_destroy</function>.
2429 Functions <function>ZOOM_scanset_option_get</function> and
2430 <function>ZOOM_scanset_option_set</function> retrieves and sets
2431 an option respectively.
2434 The <parameter>startpqf</parameter> is a subset of PQF, namely
2435 the Attributes+Term part. Multiple <literal>@attr</literal> can
2436 be used. For example to scan in title (complete) phrases:
2438 @attr 1=4 @attr 6=2 "science o"
2442 The <function>ZOOM_connecton_scan1</function> is a newer and
2443 more generic alternative to <function>ZOOM_connection_scan</function>
2444 which allows to use both CQL and PQF for Scan.
2446 <table frame="top" id="zoom.scanset.options">
2447 <title>ZOOM Scan Set Options</title>
2449 <colspec colwidth="4*" colname="name"></colspec>
2450 <colspec colwidth="7*" colname="description"></colspec>
2451 <colspec colwidth="2*" colname="default"></colspec>
2454 <entry>Option</entry>
2455 <entry>Description</entry>
2456 <entry>Default</entry>
2461 number</entry><entry>Number of Scan Terms requested in next scan.
2462 After scan it holds the actual number of terms returned.
2463 </entry><entry>20</entry></row>
2465 position</entry><entry>Preferred Position of term in response
2466 in next scan; actual position after completion of scan.
2467 </entry><entry>1</entry></row>
2469 stepSize</entry><entry>Step Size
2470 </entry><entry>0</entry></row>
2472 scanStatus</entry><entry>An integer indicating the Scan Status
2474 </entry><entry>0</entry></row>
2476 rpnCharset</entry><entry>Character set for RPN terms.
2477 If this is set, ZOOM C will assume that the ZOOM application is
2478 running UTF-8. Terms in RPN queries are then converted to the
2479 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2480 of RPN terms and no conversion is performed.
2481 </entry><entry>none</entry></row>
2486 <sect1 id="zoom.extendedservices">
2487 <title>Extended Services</title>
2489 ZOOM offers an interface to a subset of the Z39.50 extended services
2490 as well as a few privately defined ones:
2495 Z39.50 Item Order (ILL).
2496 See <xref linkend="zoom.item.order"/>.
2501 Record Update. This allows a client to insert, modify or delete
2503 See <xref linkend="zoom.record.update"/>.
2508 Database Create. This a non-standard feature. Allows a client
2509 to create a database.
2510 See <xref linkend="zoom.database.create"/>.
2515 Database Drop. This a non-standard feature. Allows a client
2516 to delete/drop a database.
2517 See <xref linkend="zoom.database.drop"/>.
2522 Commit operation. This a non-standard feature. Allows a client
2523 to commit operations.
2524 See <xref linkend="zoom.commit"/>.
2527 <!-- all the ILL PDU options should go here too -->
2530 To create an extended service operation, a <literal>ZOOM_package</literal>
2531 must be created. The operation is a five step operation. The
2532 package is created, package is configured by means of options,
2533 the package is sent, result is inspected (by means of options),
2534 the package is destroyed.
2537 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2538 ZOOM_options options);
2540 const char *ZOOM_package_option_get(ZOOM_package p,
2542 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2544 void ZOOM_package_send(ZOOM_package p, const char *type);
2546 void ZOOM_package_destroy(ZOOM_package p);
2549 The <function>ZOOM_connection_package</function> creates a
2550 package for the connection given using the options specified.
2553 Functions <function>ZOOM_package_option_get</function> and
2554 <function>ZOOM_package_option_set</function> gets and sets
2558 <function>ZOOM_package_send</function> sends
2559 the package the via connection specified in
2560 <function>ZOOM_connection_package</function>.
2561 The <parameter>type</parameter> specifies the actual extended service
2562 package type to be sent.
2564 <table frame="top" id="zoom.extendedservices.type">
2565 <title>Extended Service Type</title>
2567 <colspec colwidth="3*" colname="value"></colspec>
2568 <colspec colwidth="7*" colname="description"></colspec>
2572 <entry>Description</entry>
2577 <entry>itemorder</entry><entry>Item Order</entry>
2580 <entry>update</entry><entry>Record Update</entry>
2583 <entry>create</entry><entry>Database Create</entry>
2586 <entry>drop</entry><entry>Database Drop</entry>
2589 <entry>commit</entry><entry>Commit Operation</entry>
2595 <table frame="top" id="zoom.extendedservices.options">
2596 <title>Extended Service Common Options</title>
2598 <colspec colwidth="4*" colname="name"></colspec>
2599 <colspec colwidth="7*" colname="description"></colspec>
2600 <colspec colwidth="3*" colname="default"></colspec>
2603 <entry>Option</entry>
2604 <entry>Description</entry>
2605 <entry>Default</entry>
2610 <entry>package-name</entry>
2611 <entry>Extended Service Request package name. Must be specified
2612 as part of a request.</entry>
2616 <entry>user-id</entry>
2617 <entry>User ID of Extended Service Package. Is a request option.</entry>
2621 <entry>function</entry>
2623 Function of package - one of <literal>create</literal>,
2624 <literal>delete</literal>, <literal>modify</literal>. Is
2627 <entry><literal>create</literal></entry>
2630 <entry>waitAction</entry>
2632 Wait action for package. Possible values:
2633 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2634 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2636 <entry><literal>waitIfPossible</literal></entry>
2639 <entry>targetReference</entry>
2641 Target Reference. This is part of the response as returned
2642 by the server. Read it after a successful operation.
2644 <entry><literal>none</literal></entry>
2649 <sect2 id="zoom.item.order">
2650 <title>Item Order</title>
2652 For Item Order, <literal>type</literal> must be set to
2653 <literal>itemorder</literal> in
2654 <function>ZOOM_package_send</function>.
2657 <table frame="top" id="zoom.item.order.options">
2658 <title>Item Order Options</title>
2660 <colspec colwidth="4*" colname="name"></colspec>
2661 <colspec colwidth="7*" colname="description"></colspec>
2662 <colspec colwidth="3*" colname="default"></colspec>
2665 <entry>Option</entry>
2666 <entry>Description</entry>
2667 <entry>Default</entry>
2672 <entry>contact-name</entry>
2673 <entry>ILL contact name</entry>
2677 <entry>contact-phone</entry>
2678 <entry>ILL contact phone</entry>
2682 <entry>contact-email</entry>
2683 <entry>ILL contact email</entry>
2687 <entry>itemorder-setname</entry>
2688 <entry>Name of result set for record</entry>
2689 <entry>default</entry>
2692 <entry>itemorder-item</entry>
2693 <entry>Position for item (record) requested. An integer</entry>
2700 There are two variants of item order: ILL-variant and
2701 XML document variant. In order to use the XML variant the setting
2702 <literal>doc</literal> must hold the XML item order document. If that
2703 setting is unset, the ILL-variant is used.
2706 <table frame="top" id="zoom.illrequest.options">
2707 <title>ILL Request Options</title>
2709 <colspec colwidth="4*" colname="name"></colspec>
2712 <entry>Option</entry>
2716 <row><entry>protocol-version-num</entry></row>
2717 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,person</entry></row>
2718 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,institution</entry></row>
2719 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-person</entry></row>
2720 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2721 <row><entry>transaction-id,transaction-group-qualifier</entry></row>
2722 <row><entry>transaction-id,transaction-qualifier</entry></row>
2723 <row><entry>transaction-id,sub-transaction-qualifier</entry></row>
2724 <row><entry>service-date-time,this,date</entry></row>
2725 <row><entry>service-date-time,this,time</entry></row>
2726 <row><entry>service-date-time,original,date</entry></row>
2727 <row><entry>service-date-time,original,time</entry></row>
2728 <row><entry>requester-id,person-or-institution-symbol,person</entry></row>
2729 <row><entry>requester-id,person-or-institution-symbol,institution</entry></row>
2730 <row><entry>requester-id,name-of-person-or-institution,name-of-person</entry></row>
2731 <row><entry>requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2732 <row><entry>responder-id,person-or-institution-symbol,person</entry></row>
2733 <row><entry>responder-id,person-or-institution-symbol,institution</entry></row>
2734 <row><entry>responder-id,name-of-person-or-institution,name-of-person</entry></row>
2735 <row><entry>responder-id,name-of-person-or-institution,name-of-institution</entry></row>
2736 <row><entry>transaction-type</entry></row>
2737 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2738 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2739 <row><entry>delivery-address,postal-address,extended-postal-delivery-address</entry></row>
2740 <row><entry>delivery-address,postal-address,street-and-number</entry></row>
2741 <row><entry>delivery-address,postal-address,post-office-box</entry></row>
2742 <row><entry>delivery-address,postal-address,city</entry></row>
2743 <row><entry>delivery-address,postal-address,region</entry></row>
2744 <row><entry>delivery-address,postal-address,country</entry></row>
2745 <row><entry>delivery-address,postal-address,postal-code</entry></row>
2746 <row><entry>delivery-address,electronic-address,telecom-service-identifier</entry></row>
2747 <row><entry>delivery-address,electronic-address,telecom-service-addreess</entry></row>
2748 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2749 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2750 <row><entry>billing-address,postal-address,extended-postal-delivery-address</entry></row>
2751 <row><entry>billing-address,postal-address,street-and-number</entry></row>
2752 <row><entry>billing-address,postal-address,post-office-box</entry></row>
2753 <row><entry>billing-address,postal-address,city</entry></row>
2754 <row><entry>billing-address,postal-address,region</entry></row>
2755 <row><entry>billing-address,postal-address,country</entry></row>
2756 <row><entry>billing-address,postal-address,postal-code</entry></row>
2757 <row><entry>billing-address,electronic-address,telecom-service-identifier</entry></row>
2758 <row><entry>billing-address,electronic-address,telecom-service-addreess</entry></row>
2759 <row><entry>ill-service-type</entry></row>
2760 <row><entry>requester-optional-messages,can-send-RECEIVED</entry></row>
2761 <row><entry>requester-optional-messages,can-send-RETURNED</entry></row>
2762 <row><entry>requester-optional-messages,requester-SHIPPED</entry></row>
2763 <row><entry>requester-optional-messages,requester-CHECKED-IN</entry></row>
2764 <row><entry>search-type,level-of-service</entry></row>
2765 <row><entry>search-type,need-before-date</entry></row>
2766 <row><entry>search-type,expiry-date</entry></row>
2767 <row><entry>search-type,expiry-flag</entry></row>
2768 <row><entry>place-on-hold</entry></row>
2769 <row><entry>client-id,client-name</entry></row>
2770 <row><entry>client-id,client-status</entry></row>
2771 <row><entry>client-id,client-identifier</entry></row>
2772 <row><entry>item-id,item-type</entry></row>
2773 <row><entry>item-id,call-number</entry></row>
2774 <row><entry>item-id,author</entry></row>
2775 <row><entry>item-id,title</entry></row>
2776 <row><entry>item-id,sub-title</entry></row>
2777 <row><entry>item-id,sponsoring-body</entry></row>
2778 <row><entry>item-id,place-of-publication</entry></row>
2779 <row><entry>item-id,publisher</entry></row>
2780 <row><entry>item-id,series-title-number</entry></row>
2781 <row><entry>item-id,volume-issue</entry></row>
2782 <row><entry>item-id,edition</entry></row>
2783 <row><entry>item-id,publication-date</entry></row>
2784 <row><entry>item-id,publication-date-of-component</entry></row>
2785 <row><entry>item-id,author-of-article</entry></row>
2786 <row><entry>item-id,title-of-article</entry></row>
2787 <row><entry>item-id,pagination</entry></row>
2788 <row><entry>item-id,ISBN</entry></row>
2789 <row><entry>item-id,ISSN</entry></row>
2790 <row><entry>item-id,additional-no-letters</entry></row>
2791 <row><entry>item-id,verification-reference-source</entry></row>
2792 <row><entry>copyright-complicance</entry></row>
2793 <row><entry>retry-flag</entry></row>
2794 <row><entry>forward-flag</entry></row>
2795 <row><entry>requester-note</entry></row>
2796 <row><entry>forward-note</entry></row>
2801 <sect2 id="zoom.record.update">
2802 <title>Record Update</title>
2804 For Record Update, <literal>type</literal> must be set to
2805 <literal>update</literal> in
2806 <function>ZOOM_package_send</function>.
2808 <table frame="top" id="zoom.record.update.options">
2809 <title>Record Update Options</title>
2811 <colspec colwidth="4*" colname="name"></colspec>
2812 <colspec colwidth="7*" colname="description"></colspec>
2813 <colspec colwidth="3*" colname="default"></colspec>
2816 <entry>Option</entry>
2817 <entry>Description</entry>
2818 <entry>Default</entry>
2823 <entry>action</entry>
2825 The update action. One of
2826 <literal>specialUpdate</literal>,
2827 <literal>recordInsert</literal>,
2828 <literal>recordReplace</literal>,
2829 <literal>recordDelete</literal>,
2830 <literal>elementUpdate</literal>.
2832 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2835 <entry>recordIdOpaque</entry>
2836 <entry>Opaque Record ID</entry>
2840 <entry>recordIdNumber</entry>
2841 <entry>Record ID number</entry>
2845 <entry>record</entry>
2846 <entry>The record itself</entry>
2850 <entry>recordOpaque</entry>
2851 <entry>Specifies an opaque record which is
2852 encoded as an ASN.1 ANY type with the OID as tiven by option
2853 <literal>syntax</literal> (see below).
2854 Option <literal>recordOpaque</literal> is an alternative
2855 to record - and <literal>record</literal> option (above) is
2856 ignored if recordOpaque is set. This option is only available in
2857 YAZ 3.0.35 and later, and is meant to facilitate Updates with
2863 <entry>syntax</entry>
2864 <entry>The record syntax (transfer syntax). Is a string that
2865 is a known record syntax.
2867 <entry>no syntax</entry>
2870 <entry>databaseName</entry>
2871 <entry>Database from connection object</entry>
2872 <entry>Default</entry>
2875 <entry>correlationInfo.note</entry>
2876 <entry>Correlation Info Note (string)</entry>
2880 <entry>correlationInfo.id</entry>
2881 <entry>Correlation Info ID (integer)</entry>
2885 <entry>elementSetName</entry>
2886 <entry>Element Set for Record</entry>
2890 <entry>updateVersion</entry>
2891 <entry>Record Update version which holds one of the values
2892 1, 2 or 3. Each version has a distinct OID:
2894 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2896 (second version) and
2897 1.2.840.10003.9.5.1.1
2898 (<ulink url="&url.z39.50.extupdate3;">third and
2899 newest version</ulink>).
2909 <sect2 id="zoom.database.create"><title>Database Create</title>
2911 For Database Create, <literal>type</literal> must be set to
2912 <literal>create</literal> in
2913 <function>ZOOM_package_send</function>.
2916 <table frame="top" id="zoom.database.create.options">
2917 <title>Database Create Options</title>
2919 <colspec colwidth="4*" colname="name"></colspec>
2920 <colspec colwidth="7*" colname="description"></colspec>
2921 <colspec colwidth="3*" colname="default"></colspec>
2924 <entry>Option</entry>
2925 <entry>Description</entry>
2926 <entry>Default</entry>
2931 <entry>databaseName</entry>
2932 <entry>Database from connection object</entry>
2933 <entry>Default</entry>
2939 <sect2 id="zoom.database.drop">
2940 <title>Database Drop</title>
2942 For Database Drop, <literal>type</literal> must be set to
2943 <literal>drop</literal> in
2944 <function>ZOOM_package_send</function>.
2946 <table frame="top" id="zoom.database.drop.options">
2947 <title>Database Drop Options</title>
2949 <colspec colwidth="4*" colname="name"></colspec>
2950 <colspec colwidth="7*" colname="description"></colspec>
2951 <colspec colwidth="3*" colname="default"></colspec>
2954 <entry>Option</entry>
2955 <entry>Description</entry>
2956 <entry>Default</entry>
2961 <entry>databaseName</entry>
2962 <entry>Database from connection object</entry>
2963 <entry>Default</entry>
2969 <sect2 id="zoom.commit">
2970 <title>Commit Operation</title>
2972 For Commit, <literal>type</literal> must be set to
2973 <literal>commit</literal> in
2974 <function>ZOOM_package_send</function>.
2977 <sect2 id="zoom.extended.services.behavior">
2978 <title>Protocol behavior</title>
2980 All the extended services are Z39.50-only.
2984 The database create, drop, and commit services are privately defined
2986 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2992 <sect1 id="zoom.options">
2993 <title>Options</title>
2995 Most &zoom; objects provide a way to specify options to change behavior.
2996 From an implementation point of view, a set of options is just like
2997 an associative array / hash.
3000 ZOOM_options ZOOM_options_create(void);
3002 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
3004 void ZOOM_options_destroy(ZOOM_options opt);
3007 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
3009 void ZOOM_options_set(ZOOM_options opt, const char *name,
3013 typedef const char *(*ZOOM_options_callback)
3014 (void *handle, const char *name);
3016 ZOOM_options_callback
3017 ZOOM_options_set_callback(ZOOM_options opt,
3018 ZOOM_options_callback c,
3022 <sect1 id="zoom.queryconversions">
3023 <title>Query conversions</title>
3025 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
3026 ZOOM_connection conn);
3028 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
3030 int *ccl_error, const char **error_string,
3034 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
3035 client-side, into RPN which may be passed to the server.
3036 This is useful for servers that don't themselves
3037 support CQL, for which <function>ZOOM_query_cql</function> is useless.
3038 'conn' is used only as a place to stash diagnostics if compilation
3039 fails; if this information is not needed, a null pointer may be used.
3040 The CQL conversion is driven by option <literal>cqlfile</literal> from
3041 connection conn. This specifies a conversion file (e.g. pqf.properties)
3042 which <emphasis>must</emphasis> be present.
3045 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
3046 client-side, into RPN which may be passed to the server.
3047 The conversion is driven by the specification given by
3048 <literal>config</literal>. Upon completion 0 is returned on success; -1
3049 is returned on failure. On failure <literal>error_string</literal> and
3050 <literal>error_pos</literal> hold the error message and position of
3051 first error in original CCL string.
3054 <sect1 id="zoom.events"><title>Events</title>
3056 If you're developing non-blocking applications, you have to deal
3060 int ZOOM_event(int no, ZOOM_connection *cs);
3063 The <function>ZOOM_event</function> executes pending events for
3064 a number of connections. Supply the number of connections in
3065 <literal>no</literal> and an array of connections in
3066 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
3067 A pending event could be sending a search, receiving a response,
3069 When an event has occurred for one of the connections, this function
3070 returns a positive integer <literal>n</literal> denoting that an event
3071 occurred for connection <literal>cs[n-1]</literal>.
3072 When no events are pending for the connections, a value of zero is
3074 To ensure that all outstanding requests are performed, call this function
3075 repeatedly until zero is returned.
3078 If <function>ZOOM_event</function> returns, and returns non-zero, the
3079 last event that occurred can be expected.
3082 int ZOOM_connection_last_event(ZOOM_connection cs);
3085 <function>ZOOM_connection_last_event</function> returns an event type
3086 (integer) for the last event.
3089 <table frame="top" id="zoom.event.ids">
3090 <title>ZOOM Event IDs</title>
3092 <colspec colwidth="4*" colname="name"></colspec>
3093 <colspec colwidth="7*" colname="description"></colspec>
3096 <entry>Event</entry>
3097 <entry>Description</entry>
3102 <entry>ZOOM_EVENT_NONE</entry>
3103 <entry>No event has occurred</entry>
3106 <entry>ZOOM_EVENT_CONNECT</entry>
3107 <entry>TCP/IP connect has initiated</entry>
3110 <entry>ZOOM_EVENT_SEND_DATA</entry>
3111 <entry>Data has been transmitted (sending)</entry>
3114 <entry>ZOOM_EVENT_RECV_DATA</entry>
3115 <entry>Data has been received</entry>
3118 <entry>ZOOM_EVENT_TIMEOUT</entry>
3119 <entry>Timeout</entry>
3122 <entry>ZOOM_EVENT_UNKNOWN</entry>
3123 <entry>Unknown event</entry>
3126 <entry>ZOOM_EVENT_SEND_APDU</entry>
3127 <entry>An APDU has been transmitted (sending)</entry>
3130 <entry>ZOOM_EVENT_RECV_APDU</entry>
3131 <entry>An APDU has been received</entry>
3134 <entry>ZOOM_EVENT_RECV_RECORD</entry>
3135 <entry>A result-set record has been received</entry>
3138 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
3139 <entry>A search result has been received</entry>
3146 <chapter id="server">
3147 <title>Generic server</title>
3148 <sect1 id="server.introduction"><title>Introduction</title>
3150 If you aren't into documentation, a good way to learn how the
3151 back end interface works is to look at the <filename>backend.h</filename>
3152 file. Then, look at the small dummy-server in
3153 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
3154 file also makes a good reference, once you've chewed your way through
3155 the prose of this file.
3158 If you have a database system that you would like to make available by
3159 means of Z39.50 or SRU, &yaz; basically offers two options. You
3160 can use the APIs provided by the &asn;, &odr;, and &comstack;
3162 create and decode PDUs, and exchange them with a client.
3163 Using this low-level interface gives you access to all fields and
3164 options of the protocol, and you can construct your server as close
3165 to your existing database as you like.
3166 It is also a fairly involved process, requiring
3167 you to set up an event-handling mechanism, protocol state machine,
3168 etc. To simplify server implementation, we have implemented a compact
3169 and simple, but reasonably full-functioned server-frontend that will
3170 handle most of the protocol mechanics, while leaving you to
3171 concentrate on your database interface.
3175 The backend interface was designed in anticipation of a specific
3176 integration task, while still attempting to achieve some degree of
3177 generality. We realize fully that there are points where the
3178 interface can be improved significantly. If you have specific
3179 functions or parameters that you think could be useful, send us a
3180 mail (or better, sign on to the mailing list referred to in the
3181 top-level README file). We will try to fit good suggestions into future
3182 releases, to the extent that it can be done without requiring
3183 too many structural changes in existing applications.
3188 The &yaz; server does not support XCQL.
3192 <sect1 id="server.frontend">
3193 <title>The Database Frontend</title>
3195 We refer to this software as a generic database frontend. Your
3196 database system is the <emphasis>backend database</emphasis>, and the
3197 interface between the two is called the <emphasis>backend API</emphasis>.
3198 The backend API consists of a small number of function handlers and
3199 structure definitions. You are required to provide the
3200 <function>main()</function> routine for the server (which can be
3201 quite simple), as well as a set of handlers to match each of the
3203 The interface functions that you write can use any mechanism you like
3204 to communicate with your database system: You might link the whole
3205 thing together with your database application and access it by
3206 function calls; you might use IPC to talk to a database server
3207 somewhere; or you might link with third-party software that handles
3208 the communication for you (like a commercial database client library).
3209 At any rate, the handlers will perform the tasks of:
3222 Scanning the database index (optional - if you wish to implement SCAN).
3225 Extended Services (optional).
3228 Result-Set Delete (optional).
3231 Result-Set Sort (optional).
3234 Return Explain for SRU (optional).
3238 (more functions will be added in time to support as much of
3239 Z39.50-1995 as possible).
3242 <sect1 id="server.backend">
3243 <title>The Backend API</title>
3245 The header file that you need to use the interface are in the
3246 <filename>include/yaz</filename> directory. It's called
3247 <filename>backend.h</filename>. It will include other files from
3248 the <filename>include/yaz</filename> directory, so you'll
3249 probably want to use the -I option of your compiler to tell it
3250 where to find the files. When you run
3251 <literal>make</literal> in the top-level &yaz; directory,
3252 everything you need to create your server is to link with the
3253 <filename>lib/libyaz.la</filename> library.
3256 <sect1 id="server.main">
3257 <title>Your main() Routine</title>
3259 As mentioned, your <function>main()</function> routine can be quite brief.
3260 If you want to initialize global parameters, or read global configuration
3261 tables, this is the place to do it. At the end of the routine, you should
3265 int statserv_main(int argc, char **argv,
3266 bend_initresult *(*bend_init)(bend_initrequest *r),
3267 void (*bend_close)(void *handle));
3270 The third and fourth arguments are pointers to handlers. Handler
3271 <function>bend_init</function> is called whenever the server receives
3272 an Initialize Request, so it serves as a Z39.50 session initializer. The
3273 <function>bend_close</function> handler is called when the session is
3277 <function>statserv_main</function> will establish listening sockets
3278 according to the parameters given. When connection requests are received,
3279 the event handler will typically <function>fork()</function> and
3280 create a sub-process to handle a new connection.
3281 Alternatively the server may be setup to create threads for each
3283 If you do use global variables and forking, you should be aware, then,
3284 that these cannot be shared between associations, unless you explicitly
3285 disable forking by command line parameters.
3288 The server provides a mechanism for controlling some of its behavior
3289 without using command-line options. The function
3292 statserv_options_block *statserv_getcontrol(void);
3295 will return a pointer to a <literal>struct statserv_options_block</literal>
3296 describing the current default settings of the server. The structure
3297 contains these elements:
3300 <term><literal>int dynamic</literal></term>
3302 A boolean value, which determines whether the server
3303 will fork on each incoming request (TRUE), or not (FALSE). Default is
3304 TRUE. This flag is only read by UNIX-based servers (WIN32-based servers
3309 <term><literal>int threads</literal></term>
3311 A boolean value, which determines whether the server
3312 will create a thread on each incoming request (TRUE), or not (FALSE).
3313 Default is FALSE. This flag is only read by UNIX-based servers
3314 that offer POSIX Threads support.
3315 WIN32-based servers always operate in threaded mode.
3319 <term><literal>int inetd</literal></term>
3321 A boolean value, which determines whether the server
3322 will operate under a UNIX INET daemon (inetd). Default is FALSE.
3326 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3327 <listitem><para>File for diagnostic output ("": stderr).
3331 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3333 Name of file for logging incoming and outgoing APDUs
3334 ("": don't log APDUs, "-":
3335 <literal>stderr</literal>).
3339 <term><literal>char default_listen[1024]</literal></term>
3340 <listitem><para>Same form as the command-line specification of
3341 listener address. "": no default listener address.
3342 Default is to listen at "tcp:@:9999". You can only
3343 specify one default listener address in this fashion.
3347 <term><literal>enum oid_proto default_proto;</literal></term>
3348 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3349 <literal>PROTO_SR</literal>.
3350 Default is <literal>PROTO_Z39_50</literal>.
3354 <term><literal>int idle_timeout;</literal></term>
3355 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3356 no (infinite) timeout. Default is 15 minutes.
3360 <term><literal>int maxrecordsize;</literal></term>
3361 <listitem><para>Maximum permissible record (message) size. Default
3362 is 64 MB. This amount of memory will only be allocated if a
3363 client requests a very large amount of records in one operation
3365 Set it to a lower number if you are worried about resource
3366 consumption on your host system.
3370 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3371 <listitem><para>Passed to the backend when a new connection is received.
3375 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3376 <listitem><para>Set user id to the user specified, after binding
3377 the listener addresses.
3382 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3384 <listitem><para>Pointer to function which is called after the
3385 command line options have been parsed - but before the server
3387 For forked UNIX servers, this handler is called in the mother
3388 process; for threaded servers, this handler is called in the
3390 The default value of this pointer is NULL in which case it
3391 isn't invoked by the frontend server.
3392 When the server operates as an NT service, this handler is called
3393 whenever the service is started.
3398 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3400 <listitem><para>Pointer to function which is called whenever the server
3401 has stopped listening for incoming connections. This function pointer
3402 has a default value of NULL in which case it isn't called.
3403 When the server operates as an NT service, this handler is called
3404 whenever the service is stopped.
3408 <term><literal>void *handle</literal></term>
3409 <listitem><para>User defined pointer (default value NULL).
3410 This is a per-server handle that can be used to specify "user-data".
3411 Do not confuse this with the session-handle as returned by bend_init.
3417 The pointer returned by <literal>statserv_getcontrol</literal> points to
3418 a static area. You are allowed to change the contents of the structure,
3419 but the changes will not take effect until you call
3422 void statserv_setcontrol(statserv_options_block *block);
3426 You should generally update this structure before calling
3427 <function>statserv_main()</function>.
3431 <sect1 id="server.backendfunctions">
3432 <title>The Backend Functions</title>
3434 For each service of the protocol, the backend interface declares one or
3435 two functions. You are required to provide implementations of the
3436 functions representing the services that you wish to implement.
3438 <sect2 id="server.init">
3441 bend_initresult (*bend_init)(bend_initrequest *r);
3444 This handler is called once for each new connection request, after
3445 a new process/thread has been created, and an Initialize Request has
3446 been received from the client. The pointer to the
3447 <function>bend_init</function> handler is passed in the call to
3448 <function>statserv_start</function>.
3451 This handler is also called when operating in SRU mode - when
3452 a connection has been made (even though SRU does not offer
3456 Unlike previous versions of YAZ, the <function>bend_init</function> also
3457 serves as a handler that defines the Z39.50 services that the backend
3458 intends to support. Pointers to <emphasis>all</emphasis> service handlers,
3459 including search - and fetch must be specified here in this handler.
3462 The request - and result structures are defined as
3465 typedef struct bend_initrequest
3467 /** \brief user/name/password to be read */
3468 Z_IdAuthentication *auth;
3469 /** \brief encoding stream (for results) */
3471 /** \brief printing stream */
3473 /** \brief decoding stream (use stream for results) */
3475 /** \brief reference ID */
3476 Z_ReferenceId *referenceId;
3477 /** \brief peer address of client */
3480 /** \brief character set and language negotiation
3482 see include/yaz/z-charneg.h
3484 Z_CharSetandLanguageNegotiation *charneg_request;
3486 /** \brief character negotiation response */
3487 Z_External *charneg_response;
3489 /** \brief character set (encoding) for query terms
3491 This is NULL by default. It should be set to the native character
3492 set that the backend assumes for query terms */
3493 char *query_charset;
3495 /** \brief whehter query_charset also applies to recors
3497 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3498 character set as queries. If in doubt, use 0 (No).
3500 int records_in_same_charset;
3502 char *implementation_id;
3503 char *implementation_name;
3504 char *implementation_version;
3506 /** \brief Z39.50 sort handler */
3507 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3508 /** \brief SRU/Z39.50 search handler */
3509 int (*bend_search)(void *handle, bend_search_rr *rr);
3510 /** \brief SRU/Z39.50 fetch handler */
3511 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3512 /** \brief SRU/Z39.50 present handler */
3513 int (*bend_present)(void *handle, bend_present_rr *rr);
3514 /** \brief Z39.50 extended services handler */
3515 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3516 /** \brief Z39.50 delete result set handler */
3517 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3518 /** \brief Z39.50 scan handler */
3519 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3520 /** \brief Z39.50 segment facility handler */
3521 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3522 /** \brief SRU explain handler */
3523 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3524 /** \brief SRU scan handler */
3525 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3526 /** \brief SRU record update handler */
3527 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3529 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3530 int named_result_sets;
3533 typedef struct bend_initresult
3535 int errcode; /* 0==OK */
3536 char *errstring; /* system error string or NULL */
3537 void *handle; /* private handle to the backend module */
3541 In general, the server frontend expects that the
3542 <literal>bend_*result</literal> pointer that you return is valid at
3543 least until the next call to a <literal>bend_* function</literal>.
3544 This applies to all of the functions described herein. The parameter
3545 structure passed to you in the call belongs to the server frontend, and
3546 you should not make assumptions about its contents after the current
3547 function call has completed. In other words, if you want to retain any
3548 of the contents of a request structure, you should copy them.
3551 The <literal>errcode</literal> should be zero if the initialization of
3552 the backend went well. Any other value will be interpreted as an error.
3553 The <literal>errstring</literal> isn't used in the current version, but
3554 one option would be to stick it in the initResponse as a VisibleString.
3555 The <literal>handle</literal> is the most important parameter. It should
3556 be set to some value that uniquely identifies the current session to
3557 the backend implementation. It is used by the frontend server in any
3558 future calls to a backend function.
3559 The typical use is to set it to point to a dynamically allocated state
3560 structure that is private to your backend module.
3563 The <literal>auth</literal> member holds the authentication information
3564 part of the Z39.50 Initialize Request. Interpret this if your server
3565 requires authentication.
3568 The members <literal>peer_name</literal>,
3569 <literal>implementation_id</literal>,
3570 <literal>implementation_name</literal> and
3571 <literal>implementation_version</literal> holds
3572 DNS of client, ID of implementor, name
3573 of client (Z39.50) implementation - and version.
3576 The <literal>bend_</literal> - members are set to NULL when
3577 <function>bend_init</function> is called. Modify the pointers by
3578 setting them to point to backend functions.
3581 <sect2 id="server.search.retrieve">
3582 <title>Search and Retrieve</title>
3584 We now describe the handlers that are required to support search -
3585 and retrieve. You must support two functions - one for search - and one
3586 for fetch (retrieval of one record). If desirable you can provide a
3587 third handler which is called when a present request is received which
3588 allows you to optimize retrieval of multiple-records.
3591 int (*bend_search) (void *handle, bend_search_rr *rr);
3594 char *setname; /* name to give to this set */
3595 int replace_set; /* replace set, if it already exists */
3596 int num_bases; /* number of databases in list */
3597 char **basenames; /* databases to search */
3598 Z_ReferenceId *referenceId;/* reference ID */
3599 Z_Query *query; /* query structure */
3600 ODR stream; /* encode stream */
3601 ODR decode; /* decode stream */
3602 ODR print; /* print stream */
3604 bend_request request;
3605 bend_association association;
3607 int hits; /* number of hits */
3608 int errcode; /* 0==OK */
3609 char *errstring; /* system error string or NULL */
3610 Z_OtherInformation *search_info; /* additional search info */
3611 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3612 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3613 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3614 int estimated_hit_count; /* if hit count is estimated */
3615 int partial_resultset; /* if result set is partial */
3619 The <function>bend_search</function> handler is a fairly close
3620 approximation of a protocol Z39.50 Search Request - and Response PDUs.
3621 The <literal>setname</literal> is the resultSetName from the protocol.
3622 You are required to establish a mapping between the set name and whatever
3623 your backend database likes to use.
3624 Similarly, the <literal>replace_set</literal> is a boolean value
3625 corresponding to the resultSetIndicator field in the protocol.
3626 <literal>num_bases/basenames</literal> is a length of/array of character
3627 pointers to the database names provided by the client.
3628 The <literal>query</literal> is the full query structure as defined in
3629 the protocol ASN.1 specification.
3630 It can be either of the possible query types, and it's up to you to
3631 determine if you can handle the provided query type.
3632 Rather than reproduce the C interface here, we'll refer you to the
3633 structure definitions in the file
3634 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3635 attributeSetId OID of the RPN query, you can either match it against
3636 your own internal tables, or you can use the <link linkend="tools.oid">
3640 The structure contains a number of hits, and an
3641 <literal>errcode/errstring</literal> pair. If an error occurs
3642 during the search, or if you're unhappy with the request, you should
3643 set the errcode to a value from the BIB-1 diagnostic set. The value
3644 will then be returned to the user in a nonsurrogate diagnostic record
3645 in the response. The <literal>errstring</literal>, if provided, will
3646 go in the addinfo field. Look at the protocol definition for the
3647 defined error codes, and the suggested uses of the addinfo field.
3650 The <function>bend_search</function> handler is also called when
3651 the frontend server receives a SRU SearchRetrieveRequest.
3652 For SRU, a CQL query is usually provided by the client.
3653 The CQL query is available as part of <literal>Z_Query</literal>
3654 structure (note that CQL is now part of Z39.50 via an external).
3655 To support CQL in existing implementations that only do Type-1,
3656 we refer to the CQL-to-PQF tool described
3657 <link linkend="cql.to.pqf">here</link>.
3660 To maintain backwards compatibility, the frontend server
3661 of yaz always assume that error codes are BIB-1 diagnostics.
3662 For SRU operation, a Bib-1 diagnostic code is mapped to
3666 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3668 typedef struct bend_fetch_rr {
3669 char *setname; /* set name */
3670 int number; /* record number */
3671 Z_ReferenceId *referenceId;/* reference ID */
3672 Odr_oid *request_format; /* format, transfer syntax (OID) */
3673 Z_RecordComposition *comp; /* Formatting instructions */
3674 ODR stream; /* encoding stream - memory source if req */
3675 ODR print; /* printing stream */
3677 char *basename; /* name of database that provided record */
3678 int len; /* length of record or -1 if structured */
3679 char *record; /* record */
3680 int last_in_set; /* is it? */
3681 Odr_oid *output_format; /* response format/syntax (OID) */
3682 int errcode; /* 0==success */
3683 char *errstring; /* system error string or NULL */
3684 int surrogate_flag; /* surrogate diagnostic */
3685 char *schema; /* string record schema input/output */
3689 The frontend server calls the <function>bend_fetch</function> handler
3690 when it needs database records to fulfill a Z39.50 Search Request, a
3691 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3692 The <literal>setname</literal> is simply the name of the result set
3693 that holds the reference to the desired record.
3694 The <literal>number</literal> is the offset into the set (with 1
3695 being the first record in the set). The <literal>format</literal> field
3696 is the record format requested by the client (See
3697 <xref linkend="tools.oid"/>).
3698 A value of NULL for <literal>format</literal> indicates that the
3699 client did not request a specific format.
3700 The <literal>stream</literal> argument is an &odr; stream which
3701 should be used for allocating space for structured data records.
3702 The stream will be reset when all records have been assembled, and
3703 the response package has been transmitted.
3704 For unstructured data, the backend is responsible for maintaining a
3705 static or dynamic buffer for the record between calls.
3708 If a SRU SearchRetrieveRequest is received by the frontend server,
3709 the <literal>referenceId</literal> is NULL and the
3710 <literal>format</literal> (transfer syntax) is the OID for XML.
3711 The schema for SRU is stored in both the
3712 <literal>Z_RecordComposition</literal>
3713 structure and <literal>schema</literal> (simple string).
3716 In the structure, the <literal>basename</literal> is the name of the
3717 database that holds the
3718 record. <literal>len</literal> is the length of the record returned, in
3719 bytes, and <literal>record</literal> is a pointer to the record.
3720 <literal>last_in_set</literal> should be nonzero only if the record
3721 returned is the last one in the given result set.
3722 <literal>errcode</literal> and <literal>errstring</literal>, if
3723 given, will be interpreted as a global error pertaining to the
3724 set, and will be returned in a non-surrogate-diagnostic.
3725 If you wish to return the error as a surrogate-diagnostic
3726 (local error) you can do this by setting
3727 <literal>surrogate_flag</literal> to 1 also.
3730 If the <literal>len</literal> field has the value -1, then
3731 <literal>record</literal> is assumed to point to a constructed data
3732 type. The <literal>format</literal> field will be used to determine
3733 which encoder should be used to serialize the data.
3737 If your backend generates structured records, it should use
3738 <function>odr_malloc()</function> on the provided stream for allocating
3739 data: This allows the frontend server to keep track of the record sizes.
3743 The <literal>format</literal> field is mapped to an object identifier
3744 in the direct reference of the resulting EXTERNAL representation
3749 The current version of &yaz; only supports the direct reference mode.
3753 int (*bend_present) (void *handle, bend_present_rr *rr);
3756 char *setname; /* set name */
3758 int number; /* record number */
3759 Odr_oid *format; /* format, transfer syntax (OID) */
3760 Z_ReferenceId *referenceId;/* reference ID */
3761 Z_RecordComposition *comp; /* Formatting instructions */
3762 ODR stream; /* encoding stream - memory source if required */
3763 ODR print; /* printing stream */
3764 bend_request request;
3765 bend_association association;
3767 int hits; /* number of hits */
3768 int errcode; /* 0==OK */
3769 char *errstring; /* system error string or NULL */
3773 The <function>bend_present</function> handler is called when
3774 the server receives a Z39.50 Present Request.
3775 The <literal>setname</literal>,
3776 <literal>start</literal> and <literal>number</literal> is the
3777 name of the result set - start position - and number of records to
3778 be retrieved respectively. <literal>format</literal> and
3779 <literal>comp</literal> is the preferred transfer syntax and element
3780 specifications of the present request.
3783 Note that this is handler serves as a supplement for
3784 <function>bend_fetch</function> and need not to be defined in order to
3785 support search - and retrieve.
3788 <sect2 id="server.delete">
3789 <title>Delete</title>
3791 For back-ends that supports delete of a result set, only one handler
3795 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3797 typedef struct bend_delete_rr {
3801 Z_ReferenceId *referenceId;
3802 int delete_status; /* status for the whole operation */
3803 int *statuses; /* status each set - indexed as setnames */
3810 The delete set function definition is rather primitive, mostly because
3811 we have had no practical need for it as of yet. If someone wants
3812 to provide a full delete service, we'd be happy to add the
3813 extra parameters that are required. Are there clients out there
3814 that will actually delete sets they no longer need?
3818 <sect2 id="server.scan">
3821 For servers that wish to offer the scan service one handler
3825 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3828 BEND_SCAN_SUCCESS, /* ok */
3829 BEND_SCAN_PARTIAL /* not all entries could be found */
3832 typedef struct bend_scan_rr {
3833 int num_bases; /* number of elements in databaselist */
3834 char **basenames; /* databases to search */
3835 Odr_oid *attributeset;
3836 Z_ReferenceId *referenceId; /* reference ID */
3837 Z_AttributesPlusTerm *term;
3838 ODR stream; /* encoding stream - memory source if required */
3839 ODR print; /* printing stream */
3841 int *step_size; /* step size */
3842 int term_position; /* desired index of term in result list/returned */
3843 int num_entries; /* number of entries requested/returned */
3845 /* scan term entries. The called handler does not have
3846 to allocate this. Size of entries is num_entries (see above) */
3847 struct scan_entry *entries;
3848 bend_scan_status status;
3851 char *scanClause; /* CQL scan clause */
3852 char *setname; /* Scan in result set (NULL if omitted) */
3856 This backend server handles both Z39.50 scan
3857 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3858 Z39.50 Scan, it must check for a non-NULL value of
3859 <literal>scanClause</literal>.
3863 If designed today, it would be a choice using a union or similar,
3864 but that would break binary compatibility with existing servers.
3869 <sect1 id="server.invocation">
3870 <title>Application Invocation</title>
3872 The finished application has the following
3873 invocation syntax (by way of <function>statserv_main()</function>):
3881 A listener specification consists of a transport mode followed by a
3882 colon (:) followed by a listener address. The transport mode is
3883 either <literal>tcp</literal>, <literal>unix:</literal> or
3884 <literal>ssl</literal>.
3887 For TCP and SSL, an address has the form
3890 hostname | IP-number [: portnumber]
3893 The port number defaults to 210 (standard Z39.50 port).
3896 For UNIX, the address is the filename of socket.
3899 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3900 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3901 IPV4 binding as well (bindv6only=0),
3902 The special hostname <literal>@4</literal> binds to
3903 <literal>INADDR_ANY</literal> (IPV4 only listener).
3904 The special hostname <literal>@6</literal> binds to
3905 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3907 <example id="server.example.running.unix">
3908 <title>Running the GFS on Unix</title>
3910 Assuming the server application <replaceable>appname</replaceable> is
3911 started as root, the following will make it listen on port 210.
3912 The server will change identity to <literal>nobody</literal>
3913 and write its log to <filename>/var/log/app.log</filename>.
3915 application -l /var/log/app.log -u nobody tcp:@:210
3919 The server will accept Z39.50 requests and offer SRU service on port 210.
3922 <example id="server.example.apache.sru">
3923 <title>Setting up Apache as SRU Frontend</title>
3925 If you use <ulink url="&url.apache;">Apache</ulink>
3926 as your public web server and want to offer HTTP port 80
3927 access to the YAZ server on 210, you can use the
3928 <ulink url="&url.apache.directive.proxypass;">
3929 <literal>ProxyPass</literal></ulink>
3931 If you have virtual host
3932 <literal>srw.mydomain</literal> you can use the following directives
3933 in Apache's httpd.conf:
3936 ErrorLog /home/srw/logs/error_log
3937 TransferLog /home/srw/logs/access_log
3938 ProxyPass / http://srw.mydomain:210/
3943 The above is for the Apache 1.3 series.
3946 <example id="server.example.local.access">
3947 <title>Running a server with local access only</title>
3949 A server that is only being accessed from the local host should listen
3950 on UNIX file socket rather than an Internet socket. To listen on
3951 <filename>/tmp/mysocket</filename> start the server as follows:
3953 application unix:/tmp/mysocket
3958 <sect1 id="server.vhosts">
3959 <title>GFS Configuration and Virtual Hosts</title>
3964 <title>The Z39.50 ASN.1 Module</title>
3965 <sect1 id="asn.introduction">
3966 <title>Introduction</title>
3968 The &asn; module provides you with a set of C struct definitions for the
3969 various PDUs of the Z39.50 protocol, as well as for the complex types
3970 appearing within the PDUs. For the primitive data types, the C
3971 representation often takes the form of an ordinary C language type,
3972 such as <literal>Odr_int</literal> which is equivalent to an integral
3973 C integer. For ASN.1 constructs that have no direct
3974 representation in C, such as general octet strings and bit strings,
3975 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3976 provides auxiliary definitions.
3979 The &asn; module is located in sub directory <filename>z39.50</filename>.
3980 There you'll find C files that implement encoders and decoders for the
3981 Z39.50 types. You'll also find the protocol definitions:
3982 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3986 <sect1 id="asn.preparing">
3987 <title>Preparing PDUs</title>
3989 A structure representing a complex ASN.1 type doesn't in itself contain the
3990 members of that type. Instead, the structure contains
3991 <emphasis>pointers</emphasis> to the members of the type.
3992 This is necessary, in part, to allow a mechanism for specifying which
3993 of the optional structure (SEQUENCE) members are present, and which
3994 are not. It follows that you will need to somehow provide space for
3995 the individual members of the structure, and set the pointers to
3996 refer to the members.
3999 The conversion routines don't care how you allocate and maintain your
4000 C structures - they just follow the pointers that you provide.
4001 Depending on the complexity of your application, and your personal
4002 taste, there are at least three different approaches that you may take
4003 when you allocate the structures.
4006 You can use static or automatic local variables in the function that
4007 prepares the PDU. This is a simple approach, and it provides the most
4008 efficient form of memory management. While it works well for flat
4009 PDUs like the InitReqest, it will generally not be sufficient for say,
4010 the generation of an arbitrarily complex RPN query structure.
4013 You can individually create the structure and its members using the
4014 <function>malloc(2)</function> function. If you want to ensure that
4015 the data is freed when it is no longer needed, you will have to
4016 define a function that individually releases each member of a
4017 structure before freeing the structure itself.
4020 You can use the <function>odr_malloc()</function> function (see
4021 <xref linkend="odr.use"/> for details). When you use
4022 <function>odr_malloc()</function>, you can release all of the
4023 allocated data in a single operation, independent of any pointers and
4024 relations between the data. The <function>odr_malloc()</function> function
4025 is based on a "nibble-memory"
4026 scheme, in which large portions of memory are allocated, and then
4027 gradually handed out with each call to <function>odr_malloc()</function>.
4028 The next time you call <function>odr_reset()</function>, all of the
4029 memory allocated since the last call is recycled for future use (actually,
4030 it is placed on a free-list).
4033 You can combine all of the methods described here. This will often be
4034 the most practical approach. For instance, you might use
4035 <function>odr_malloc()</function> to allocate an entire structure and
4036 some of its elements, while you leave other elements pointing to global
4037 or per-session default variables.
4040 The &asn; module provides an important aid in creating new PDUs. For
4041 each of the PDU types (say, <function>Z_InitRequest</function>), a
4042 function is provided that allocates and initializes an instance of
4043 that PDU type for you. In the case of the InitRequest, the function is
4044 simply named <function>zget_InitRequest()</function>, and it sets up
4045 reasonable default value for all of the mandatory members. The optional
4046 members are generally initialized to null pointers. This last aspect
4047 is very important: it ensures that if the PDU definitions are
4048 extended after you finish your implementation (to accommodate
4049 new versions of the protocol, say), you won't get into trouble with
4050 uninitialized pointers in your structures. The functions use
4051 <function>odr_malloc()</function> to
4052 allocate the PDUs and its members, so you can free everything again with a
4053 single call to <function>odr_reset()</function>. We strongly recommend
4054 that you use the <literal>zget_*</literal>
4055 functions whenever you are preparing a PDU (in a C++ API, the
4056 <literal>zget_</literal>
4057 functions would probably be promoted to constructors for the
4061 The prototype for the individual PDU types generally look like this:
4064 Z_<type> *zget_<type>(ODR o);
4070 Z_InitRequest *zget_InitRequest(ODR o);
4073 The &odr; handle should generally be your encoding stream, but it
4077 As well as the individual PDU functions, a function
4078 <function>zget_APDU()</function> is provided, which allocates
4079 a top-level Z-APDU of the type requested:
4082 Z_APDU *zget_APDU(ODR o, int which);
4085 The <varname>which</varname> parameter is (of course) the discriminator
4086 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
4087 All of the interface described here is provided by the &asn; module, and
4088 you access it through the <filename>proto.h</filename> header file.
4091 <sect1 id="asn.external">
4092 <title>EXTERNAL Data</title>
4094 In order to achieve extensibility and adaptability to different
4095 application domains, the new version of the protocol defines many
4096 structures outside of the main ASN.1 specification, referencing them
4097 through ASN.1 EXTERNAL constructs. To simplify the construction and
4098 access to the externally referenced data, the &asn; module defines a
4099 specialized version of the EXTERNAL construct, called
4100 <literal>Z_External</literal>.It is defined thus:
4103 typedef struct Z_External
4105 Odr_oid *direct_reference;
4106 int *indirect_reference;
4111 Z_External_single = 0,
4113 Z_External_arbitrary,
4115 /* Specific types */
4117 Z_External_explainRecord,
4118 Z_External_resourceReport1,
4119 Z_External_resourceReport2
4127 Odr_any *single_ASN1_type;
4128 Odr_oct *octet_aligned;
4129 Odr_bitmask *arbitrary;
4131 /* Specific types */
4133 Z_ExplainRecord *explainRecord;
4134 Z_ResourceReport1 *resourceReport1;
4135 Z_ResourceReport2 *resourceReport2;
4143 When decoding, the &asn; module will attempt to determine which
4144 syntax describes the data by looking at the reference fields
4145 (currently only the direct-reference). For ASN.1 structured data, you
4146 need only consult the <literal>which</literal> field to determine the
4147 type of data. You can the access the data directly through the union.
4148 When constructing data for encoding, you set the union pointer to point
4149 to the data, and set the <literal>which</literal> field accordingly.
4150 Remember also to set the direct (or indirect) reference to the correct
4151 OID for the data type.
4152 For non-ASN.1 data such as MARC records, use the
4153 <literal>octet_aligned</literal> arm of the union.
4156 Some servers return ASN.1 structured data values (e.g. database
4157 records) as BER-encoded records placed in the
4158 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
4159 The ASN-module will <emphasis>not</emphasis> automatically decode
4160 these records. To help you decode the records in the application, the
4164 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
4167 can be used to retrieve information about the known, external data
4168 types. The function returns a pointer to a static area, or NULL, if no
4169 match for the given direct reference is found. The
4170 <literal>Z_ext_typeent</literal>
4174 typedef struct Z_ext_typeent
4176 int oid[OID_SIZE]; /* the direct-reference OID. */
4177 int what; /* discriminator value for the external CHOICE */
4178 Odr_fun fun; /* decoder function */
4182 The <literal>what</literal> member contains the
4183 <literal>Z_External</literal> union discriminator value for the
4184 given type: For the SUTRS record syntax, the value would be
4185 <literal>Z_External_sutrs</literal>.
4186 The <literal>fun</literal> member contains a pointer to the
4187 function which encodes/decodes the given type. Again, for the SUTRS
4188 record syntax, the value of <literal>fun</literal> would be
4189 <literal>z_SUTRS</literal> (a function pointer).
4192 If you receive an EXTERNAL which contains an octet-string value that
4193 you suspect of being an ASN.1-structured data value, you can use
4194 <literal>z_ext_gettypebyref</literal> to look for the provided
4196 If the return value is different from NULL, you can use the provided
4197 function to decode the BER string (see <xref linkend="odr.use"/>
4201 If you want to <emphasis>send</emphasis> EXTERNALs containing
4202 ASN.1-structured values in the octet-aligned branch of the CHOICE, this
4203 is possible too. However, on the encoding phase, it requires a somewhat
4204 involved juggling around of the various buffers involved.
4207 If you need to add new, externally defined data types, you must update
4208 the struct above, in the source file <filename>prt-ext.h</filename>, as
4209 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4210 When changing the latter, remember to update both the
4211 <literal>arm</literal> arrary and the list
4212 <literal>type_table</literal>, which drives the CHOICE biasing that
4213 is necessary to tell the different, structured types apart
4218 Eventually, the EXTERNAL processing will most likely
4219 automatically insert the correct OIDs or indirect-refs. First,
4220 however, we need to determine how application-context management
4221 (specifically the presentation-context-list) should fit into the
4226 <sect1 id="asn.pdu">
4227 <title>PDU Contents Table</title>
4229 We include, for reference, a listing of the fields of each top-level
4230 PDU, as well as their default settings.
4232 <table frame="top" id="asn.default.initialize.request">
4233 <title>Default settings for PDU Initialize Request</title>
4235 <colspec colwidth="7*" colname="field"></colspec>
4236 <colspec colwidth="5*" colname="type"></colspec>
4237 <colspec colwidth="7*" colname="value"></colspec>
4240 <entry>Field</entry>
4242 <entry>Default Value</entry>
4247 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4250 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4253 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4256 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4259 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4262 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4265 implementationId</entry><entry>char*</entry><entry>"81"
4268 implementationName</entry><entry>char*</entry><entry>"YAZ"
4271 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4274 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4277 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4282 <table frame="top" id="asn.default.initialize.response">
4283 <title>Default settings for PDU Initialize Response</title>
4285 <colspec colwidth="7*" colname="field"></colspec>
4286 <colspec colwidth="5*" colname="type"></colspec>
4287 <colspec colwidth="7*" colname="value"></colspec>
4290 <entry>Field</entry>
4292 <entry>Default Value</entry>
4297 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4300 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4303 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4306 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4309 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4312 result</entry><entry>Odr_bool</entry><entry>TRUE
4315 implementationId</entry><entry>char*</entry><entry>"id)"
4318 implementationName</entry><entry>char*</entry><entry>"YAZ"
4321 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4324 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4327 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4332 <table frame="top" id="asn.default.search.request">
4333 <title>Default settings for PDU Search Request</title>
4335 <colspec colwidth="7*" colname="field"></colspec>
4336 <colspec colwidth="5*" colname="type"></colspec>
4337 <colspec colwidth="7*" colname="value"></colspec>
4340 <entry>Field</entry>
4342 <entry>Default Value</entry>
4347 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4350 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4353 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4356 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4359 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4362 resultSetName</entry><entry>char *</entry><entry>"default"
4365 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4368 databaseNames</entry><entry>char **</entry><entry>NULL
4371 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4375 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4379 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4382 query</entry><entry>Z_Query</entry><entry>NULL
4385 additionalSearchInfo</entry><entry>Z_OtherInformation
4389 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4394 <table frame="top" id="asn.default.search.response">
4395 <title>Default settings for PDU Search Response</title>
4397 <colspec colwidth="7*" colname="field"></colspec>
4398 <colspec colwidth="5*" colname="type"></colspec>
4399 <colspec colwidth="7*" colname="value"></colspec>
4402 <entry>Field</entry>
4404 <entry>Default Value</entry>
4409 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4412 resultCount</entry><entry>Odr_int</entry><entry>0
4415 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4418 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4421 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4424 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4427 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4430 records</entry><entry>Z_Records</entry><entry>NULL
4433 additionalSearchInfo</entry>
4434 <entry>Z_OtherInformation</entry><entry>NULL
4437 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4442 <table frame="top" id="asn.default.present.request">
4443 <title>Default settings for PDU Present Request</title>
4445 <colspec colwidth="7*" colname="field"></colspec>
4446 <colspec colwidth="5*" colname="type"></colspec>
4447 <colspec colwidth="7*" colname="value"></colspec>
4450 <entry>Field</entry>
4452 <entry>Default Value</entry>
4457 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4460 resultSetId</entry><entry>char*</entry><entry>"default"
4463 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4466 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4469 num_ranges</entry><entry>Odr_int</entry><entry>0
4472 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4475 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4478 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4481 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4484 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4487 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4490 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4495 <table frame="top" id="asn.default.present.response">
4496 <title>Default settings for PDU Present Response</title>
4498 <colspec colwidth="7*" colname="field"></colspec>
4499 <colspec colwidth="5*" colname="type"></colspec>
4500 <colspec colwidth="7*" colname="value"></colspec>
4503 <entry>Field</entry>
4505 <entry>Default Value</entry>
4510 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4513 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4516 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4519 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4522 records</entry><entry>Z_Records</entry><entry>NULL
4525 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4530 <table frame="top" id="asn.default.delete.result.set.request">
4531 <title>Default settings for Delete Result Set Request</title>
4533 <colspec colwidth="7*" colname="field"></colspec>
4534 <colspec colwidth="5*" colname="type"></colspec>
4535 <colspec colwidth="7*" colname="value"></colspec>
4538 <entry>Field</entry>
4540 <entry>Default Value</entry>
4544 <row><entry>referenceId
4545 </entry><entry>Z_ReferenceId</entry><entry>NULL
4548 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4551 num_ids</entry><entry>Odr_int</entry><entry>0
4554 resultSetList</entry><entry>char**</entry><entry>NULL
4557 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4562 <table frame="top" id="asn.default.delete.result.set.response">
4563 <title>Default settings for Delete Result Set Response</title>
4565 <colspec colwidth="7*" colname="field"></colspec>
4566 <colspec colwidth="5*" colname="type"></colspec>
4567 <colspec colwidth="7*" colname="value"></colspec>
4570 <entry>Field</entry>
4572 <entry>Default Value</entry>
4577 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4580 deleteOperationStatus</entry><entry>Odr_int</entry>
4581 <entry>Z_DeleteStatus_success</entry></row>
4583 num_statuses</entry><entry>Odr_int</entry><entry>0
4586 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4589 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4592 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4595 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4598 deleteMessage</entry><entry>char*</entry><entry>NULL
4601 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4606 <table frame="top" id="asn.default.scan.request">
4607 <title>Default settings for Scan Request</title>
4609 <colspec colwidth="7*" colname="field"></colspec>
4610 <colspec colwidth="5*" colname="type"></colspec>
4611 <colspec colwidth="7*" colname="value"></colspec>
4614 <entry>Field</entry>
4616 <entry>Default Value</entry>
4621 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4624 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4627 databaseNames</entry><entry>char**</entry><entry>NULL
4630 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4633 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4634 </entry><entry>NULL</entry></row>
4636 stepSize</entry><entry>Odr_int</entry><entry>NULL
4639 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4642 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4645 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4650 <table frame="top" id="asn.default.scan.response">
4651 <title>Default settings for Scan Response</title>
4653 <colspec colwidth="7*" colname="field"></colspec>
4654 <colspec colwidth="5*" colname="type"></colspec>
4655 <colspec colwidth="7*" colname="value"></colspec>
4658 <entry>Field</entry>
4660 <entry>Default Value</entry>
4665 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4668 stepSize</entry><entry>Odr_int</entry><entry>NULL
4671 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4674 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4677 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4680 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4683 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4686 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4691 <table frame="top" id="asn.default.trigger.resource.control.request">
4692 <title>Default settings for Trigger Resource Control Request</title>
4694 <colspec colwidth="7*" colname="field"></colspec>
4695 <colspec colwidth="5*" colname="type"></colspec>
4696 <colspec colwidth="7*" colname="value"></colspec>
4699 <entry>Field</entry>
4701 <entry>Default Value</entry>
4706 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4709 requestedAction</entry><entry>Odr_int</entry><entry>
4710 Z_TriggerResourceCtrl_resou..
4713 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4716 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4719 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4724 <table frame="top" id="asn.default.resource.control.request">
4725 <title>Default settings for Resource Control Request</title>
4727 <colspec colwidth="7*" colname="field"></colspec>
4728 <colspec colwidth="5*" colname="type"></colspec>
4729 <colspec colwidth="7*" colname="value"></colspec>
4732 <entry>Field</entry>
4734 <entry>Default Value</entry>
4739 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4742 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4745 resourceReport</entry><entry>Z_External</entry><entry>NULL
4748 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4751 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4754 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4757 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4762 <table frame="top" id="asn.default.resource.control.response">
4763 <title>Default settings for Resource Control Response</title>
4765 <colspec colwidth="7*" colname="field"></colspec>
4766 <colspec colwidth="5*" colname="type"></colspec>
4767 <colspec colwidth="7*" colname="value"></colspec>
4770 <entry>Field</entry>
4772 <entry>Default Value</entry>
4777 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4780 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4783 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4786 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4791 <table frame="top" id="asn.default.access.control.request">
4792 <title>Default settings for Access Control Request</title>
4794 <colspec colwidth="7*" colname="field"></colspec>
4795 <colspec colwidth="5*" colname="type"></colspec>
4796 <colspec colwidth="7*" colname="value"></colspec>
4799 <entry>Field</entry>
4801 <entry>Default Value</entry>
4806 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4809 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4812 u</entry><entry>union</entry><entry>NULL
4815 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4820 <table frame="top" id="asn.default.access.control.response">
4821 <title>Default settings for Access Control Response</title>
4823 <colspec colwidth="7*" colname="field"></colspec>
4824 <colspec colwidth="5*" colname="type"></colspec>
4825 <colspec colwidth="7*" colname="value"></colspec>
4828 <entry>Field</entry>
4830 <entry>Default Value</entry>
4835 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4838 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4841 u</entry><entry>union</entry><entry>NULL
4844 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4847 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4852 <table frame="top" id="asn.default.segment">
4853 <title>Default settings for Segment</title>
4855 <colspec colwidth="7*" colname="field"></colspec>
4856 <colspec colwidth="5*" colname="type"></colspec>
4857 <colspec colwidth="7*" colname="value"></colspec>
4860 <entry>Field</entry>
4862 <entry>Default Value</entry>
4867 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4870 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4873 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4876 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4878 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4883 <table frame="top" id="asn.default.close">
4884 <title>Default settings for Close</title>
4886 <colspec colwidth="7*" colname="field"></colspec>
4887 <colspec colwidth="5*" colname="type"></colspec>
4888 <colspec colwidth="7*" colname="value"></colspec>
4891 <entry>Field</entry>
4893 <entry>Default Value</entry>
4898 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4901 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4904 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4907 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4910 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4913 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4921 <title>SOAP and SRU</title>
4922 <sect1 id="soap.introduction">
4923 <title>Introduction</title>
4925 &yaz; uses a very simple implementation of
4926 <ulink url="&url.soap;">SOAP</ulink> that only
4927 (currently) supports what is sufficient to offer SRU SOAP functionality.
4928 The implementation uses the
4929 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4930 libxml2 to encode and decode SOAP packages.
4933 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4934 simple C structs to represent SOAP packages as well as
4938 <sect1 id="soap.http">
4941 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4942 relatively easy to change that.
4945 The following definition of <literal>Z_GDU</literal> (Generic Data
4946 Unit) allows for both HTTP and Z39.50 in one packet.
4949 #include <yaz/zgdu.h>
4951 #define Z_GDU_Z3950 1
4952 #define Z_GDU_HTTP_Request 2
4953 #define Z_GDU_HTTP_Response 3
4958 Z_HTTP_Request *HTTP_Request;
4959 Z_HTTP_Response *HTTP_Response;
4964 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4965 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4967 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4968 is the HTTP Request and Response respectively.
4971 <sect1 id="soap.xml">
4972 <title>SOAP Packages</title>
4974 Every SOAP package in &yaz; is represented as follows:
4976 #include <yaz/soap.h>
4990 #define Z_SOAP_fault 1
4991 #define Z_SOAP_generic 2
4992 #define Z_SOAP_error 3
4996 Z_SOAP_Fault *fault;
4997 Z_SOAP_Generic *generic;
4998 Z_SOAP_Fault *soap_error;
5005 The <literal>fault</literal> and <literal>soap_error</literal>
5006 arms both represent a SOAP fault - struct
5007 <literal>Z_SOAP_Fault</literal>. Any other generic
5008 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
5011 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
5012 is the namespace for SOAP itself and reflects the SOAP
5013 version. For version 1.1 it is
5014 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
5015 for version 1.2 it is
5016 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
5019 int z_soap_codec(ODR o, Z_SOAP **pp,
5020 char **content_buf, int *content_len,
5021 Z_SOAP_Handler *handlers);
5024 The <literal>content_buf</literal> and <literal>content_len</literal>
5025 is XML buffer and length of buffer respectively.
5028 The <literal>handlers</literal> is a list of SOAP codec
5029 handlers - one handler for each service namespace. For SRU SOAP, the
5030 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
5033 When decoding, the <function>z_soap_codec</function>
5034 inspects the XML content
5035 and tries to match one of the services namespaces of the
5036 supplied handlers. If there is a match. a handler function
5037 is invoked which decodes that particular SOAP package.
5038 If successful, the returned <literal>Z_SOAP</literal> package will be
5039 of type <literal>Z_SOAP_Generic</literal>.
5040 Member <literal>no</literal> is
5041 set the offset of the handler that matched; <literal>ns</literal>
5042 is set to namespace of the matching handler; the void pointer
5043 <literal>p</literal> is set to the C data structure assocatiated
5047 When a NULL namespace is met (member <literal>ns</literal> below),
5048 that specifies end-of-list.
5051 Each handler is defined as follows:
5059 The <literal>ns</literal> is the namespace of the service associated with
5060 handler <literal>f</literal>. The <literal>client_data</literal>
5061 is user-defined data which is passed to the handler.
5064 The prototype for a SOAP service handler is:
5066 int handler(ODR o, void * ptr, void **handler_data,
5067 void *client_data, const char *ns);
5069 The <parameter>o</parameter> specifies the mode (decode/encode)
5070 as usual. The second argument, <parameter>ptr</parameter>,
5071 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
5072 and is a pointer to the <literal>Body</literal> element
5073 of the SOAP package. The <parameter>handler_data</parameter>
5074 is an opaque pointer to C definitions associated with the
5075 SOAP service. The <parameter>client_data</parameter> is the pointer
5076 which was set as part of the <literal>Z_SOAP_handler</literal>.
5077 Finally, <parameter>ns</parameter> is the service namespace.
5080 <sect1 id="soap.srw">
5083 SRU SOAP is just one implementation of a SOAP handler as described
5084 in the previous section.
5085 The encoder/decoder handler for SRU is defined as
5088 #include <yaz/srw.h>
5090 int yaz_srw_codec(ODR o, void * pptr,
5091 Z_SRW_GDU **handler_data,
5092 void *client_data, const char *ns);
5094 Here, <literal>Z_SRW_GDU</literal> is either
5095 searchRetrieveRequest or a searchRetrieveResponse.
5099 The xQuery and xSortKeys are not handled yet by
5100 the SRW implementation of &yaz;. Explain is also missing.
5101 Future versions of &yaz; will include these features.
5105 The definition of searchRetrieveRequest is:
5109 #define Z_SRW_query_type_cql 1
5110 #define Z_SRW_query_type_xcql 2
5111 #define Z_SRW_query_type_pqf 3
5119 #define Z_SRW_sort_type_none 1
5120 #define Z_SRW_sort_type_sort 2
5121 #define Z_SRW_sort_type_xSort 3
5129 int *maximumRecords;
5131 char *recordPacking;
5133 } Z_SRW_searchRetrieveRequest;
5135 Please observe that data of type xsd:string is represented
5136 as a char pointer (<literal>char *</literal>). A null pointer
5137 means that the element is absent.
5138 Data of type xsd:integer is represented as a pointer to
5139 an int (<literal>int *</literal>). Again, a null pointer
5140 is used for absent elements.
5143 The SearchRetrieveResponse has the following definition.
5146 int * numberOfRecords;
5148 int * resultSetIdleTime;
5150 Z_SRW_record *records;
5153 Z_SRW_diagnostic *diagnostics;
5154 int num_diagnostics;
5155 int *nextRecordPosition;
5156 } Z_SRW_searchRetrieveResponse;
5158 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
5159 is number of returned records and diagnostics respectively, and also
5160 correspond to the "size of" arrays <literal>records</literal>
5161 and <literal>diagnostics</literal>.
5164 A retrieval record is defined as follows:
5168 char *recordData_buf;
5170 int *recordPosition;
5173 The record data is defined as a buffer of some length so that
5174 data can be of any type. SRW 1.0 currenly doesn't allow for this
5175 (only XML), but future versions might do.
5178 And, a diagnostic as:
5188 <chapter id="tools">
5189 <title>Supporting Tools</title>
5191 In support of the service API - primarily the ASN module, which
5192 provides the programmatic interface to the Z39.50 APDUs, &yaz; contains
5193 a collection of tools that support the development of applications.
5195 <sect1 id="tools.query">
5196 <title>Query Syntax Parsers</title>
5198 Since the type-1 (RPN) query structure has no direct, useful string
5199 representation, every origin application needs to provide some form of
5200 mapping from a local query notation or representation to a
5201 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5202 construct the query manually, perhaps using
5203 <function>odr_malloc()</function> to simplify memory management.
5204 The &yaz; distribution includes three separate, query-generating tools
5205 that may be of use to you.
5208 <title>Prefix Query Format</title>
5210 Since RPN or reverse polish notation is really just a fancy way of
5211 describing a suffix notation format (operator follows operands), it
5212 would seem that the confusion is total when we now introduce a prefix
5213 notation for RPN. The reason is one of simple laziness - it's somewhat
5214 simpler to interpret a prefix format, and this utility was designed
5215 for maximum simplicity, to provide a baseline representation for use
5216 in simple test applications and scripting environments (like Tcl). The
5217 demonstration client included with YAZ uses the PQF.
5221 The PQF has been adopted by other parties developing Z39.50
5222 software. It is often referred to as Prefix Query Notation
5227 The PQF is defined by the pquery module in the YAZ library.
5228 There are two sets of functions that have similar behavior. First
5229 set operates on a PQF parser handle, second set doesn't. First set
5230 of functions are more flexible than the second set. Second set
5231 is obsolete and is only provided to ensure backwards compatibility.
5234 First set of functions all operate on a PQF parser handle:
5237 #include <yaz/pquery.h>
5239 YAZ_PQF_Parser yaz_pqf_create(void);
5241 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5243 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5245 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5246 Odr_oid **attributeSetId, const char *qbuf);
5248 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5251 A PQF parser is created and destructed by functions
5252 <function>yaz_pqf_create</function> and
5253 <function>yaz_pqf_destroy</function> respectively.
5254 Function <function>yaz_pqf_parse</function> parses the query given
5255 by string <literal>qbuf</literal>. If parsing was successful,
5256 a Z39.50 RPN Query is returned which is created using ODR stream
5257 <literal>o</literal>. If parsing failed, a NULL pointer is
5259 Function <function>yaz_pqf_scan</function> takes a scan query in
5260 <literal>qbuf</literal>. If parsing was successful, the function
5261 returns attributes plus term pointer and modifies
5262 <literal>attributeSetId</literal> to hold attribute set for the
5263 scan request - both allocated using ODR stream <literal>o</literal>.
5264 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5265 Error information for bad queries can be obtained by a call to
5266 <function>yaz_pqf_error</function> which returns an error code and
5267 modifies <literal>*msg</literal> to point to an error description,
5268 and modifies <literal>*off</literal> to the offset within the last
5269 query where parsing failed.
5272 The second set of functions are declared as follows:
5275 #include <yaz/pquery.h>
5277 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5279 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5280 Odr_oid **attributeSetP, const char *qbuf);
5282 int p_query_attset(const char *arg);
5285 The function <function>p_query_rpn()</function> takes as arguments an
5286 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5287 to provide a memory source (the structure created is released on
5288 the next call to <function>odr_reset()</function> on the stream), a
5289 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5290 <token>PROTO_SR</token>), an attribute set reference, and
5291 finally a null-terminated string holding the query string.
5294 If the parse went well, <function>p_query_rpn()</function> returns a
5295 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5296 placed directly into a <literal>Z_SearchRequest</literal>.
5297 If parsing failed, due to syntax error, a NULL pointer is returned.
5300 The <literal>p_query_attset</literal> specifies which attribute set
5301 to use if the query doesn't specify one by the
5302 <literal>@attrset</literal> operator.
5303 The <literal>p_query_attset</literal> returns 0 if the argument is a
5304 valid attribute set specifier; otherwise the function returns -1.
5307 The grammar of the PQF is as follows:
5310 query ::= top-set query-struct.
5312 top-set ::= [ '@attrset' string ]
5314 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5316 attr-spec ::= '@attr' [ string ] string query-struct
5318 complex ::= operator query-struct query-struct.
5320 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5322 simple ::= result-set | term.
5324 result-set ::= '@set' string.
5328 proximity ::= exclusion distance ordered relation which-code unit-code.
5330 exclusion ::= '1' | '0' | 'void'.
5332 distance ::= integer.
5334 ordered ::= '1' | '0'.
5336 relation ::= integer.
5338 which-code ::= 'known' | 'private' | integer.
5340 unit-code ::= integer.
5342 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5345 You will note that the syntax above is a fairly faithful
5346 representation of RPN, except for the Attribute, which has been
5347 moved a step away from the term, allowing you to associate one or more
5348 attributes with an entire query structure. The parser will
5349 automatically apply the given attributes to each term as required.
5352 The @attr operator is followed by an attribute specification
5353 (<literal>attr-spec</literal> above). The specification consists
5354 of an optional attribute set, an attribute type-value pair and
5355 a sub-query. The attribute type-value pair is packed in one string:
5356 an attribute type, an equals sign, and an attribute value, like this:
5357 <literal>@attr 1=1003</literal>.
5358 The type is always an integer, but the value may be either an
5359 integer or a string (if it doesn't start with a digit character).
5360 A string attribute-value is encoded as a Type-1 "complex"
5361 attribute with the list of values containing the single string
5362 specified, and including no semantic indicators.
5365 Version 3 of the Z39.50 specification defines various encoding of terms.
5366 Use <literal>@term </literal> <replaceable>type</replaceable>
5367 <replaceable>string</replaceable>,
5368 where type is one of: <literal>general</literal>,
5369 <literal>numeric</literal> or <literal>string</literal>
5370 (for InternationalString).
5371 If no term type has been given, the <literal>general</literal> form
5372 is used. This is the only encoding allowed in both versions 2 and 3
5373 of the Z39.50 standard.
5375 <sect3 id="PQF-prox">
5376 <title>Using Proximity Operators with PQF</title>
5379 This is an advanced topic, describing how to construct
5380 queries that make very specific requirements on the
5381 relative location of their operands.
5382 You may wish to skip this section and go straight to
5383 <link linkend="pqf-examples">the example PQF queries</link>.
5388 Most Z39.50 servers do not support proximity searching, or
5389 support only a small subset of the full functionality that
5390 can be expressed using the PQF proximity operator. Be
5391 aware that the ability to <emphasis>express</emphasis> a
5392 query in PQF is no guarantee that any given server will
5393 be able to <emphasis>execute</emphasis> it.
5399 The proximity operator <literal>@prox</literal> is a special
5400 and more restrictive version of the conjunction operator
5401 <literal>@and</literal>. Its semantics are described in
5402 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5403 can be read on-line at
5404 <ulink url="&url.z39.50.proximity;"/>
5407 In PQF, the proximity operation is represented by a sequence
5410 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5412 in which the meanings of the parameters are as described in
5413 the standard, and they can take the following values:
5416 <formalpara><title>exclusion</title>
5418 0 = false (i.e. the proximity condition specified by the
5419 remaining parameters must be satisfied) or
5420 1 = true (the proximity condition specified by the
5421 remaining parameters must <emphasis>not</emphasis> be
5427 <formalpara><title>distance</title><para>
5428 An integer specifying the difference between the locations
5429 of the operands: e.g. two adjacent words would have
5430 distance=1 since their locations differ by one unit.
5432 </formalpara></listitem>
5434 <formalpara><title>ordered</title><para>
5435 1 = ordered (the operands must occur in the order the
5436 query specifies them) or
5437 0 = unordered (they may appear in either order).
5442 <formalpara><title>relation</title><para>
5443 Recognised values are
5445 2 (lessThanOrEqual),
5447 4 (greaterThanOrEqual),
5454 <formalpara><title>which-code</title><para>
5455 <literal>known</literal>
5457 <literal>k</literal>
5458 (the unit-code parameter is taken from the well-known list
5459 of alternatives described below) or
5460 <literal>private</literal>
5462 <literal>p</literal>
5463 (the unit-code parameter has semantics specific to an
5464 out-of-band agreement such as a profile).
5469 <formalpara><title>unit-code</title><para>
5470 If the which-code parameter is <literal>known</literal>
5471 then the recognised values are
5481 10 (elementType) and
5483 If which-code is <literal>private</literal> then the
5484 acceptable values are determined by the profile.
5489 (The numeric values of the relation and well-known unit-code
5490 parameters are taken straight from
5491 <ulink url="&url.z39.50.proximity.asn1;"
5492 >the ASN.1</ulink> of the proximity structure in the standard.)
5495 <sect3 id="pqf-examples">
5496 <title>PQF queries</title>
5497 <example id="example.pqf.simple.terms">
5498 <title>PQF queries using simple terms</title>
5507 <example id="pqf.example.pqf.boolean.operators">
5508 <title>PQF boolean operators</title>
5511 @or "dylan" "zimmerman"
5513 @and @or dylan zimmerman when
5515 @and when @or dylan zimmerman
5519 <example id="example.pqf.result.sets">
5520 <title>PQF references to result sets</title>
5525 @and @set seta @set setb
5529 <example id="example.pqf.attributes">
5530 <title>Attributes for terms</title>
5535 @attr 1=4 @attr 4=1 "self portrait"
5537 @attrset exp1 @attr 1=1 CategoryList
5539 @attr gils 1=2008 Copenhagen
5541 @attr 1=/book/title computer
5545 <example id="example.pqf.proximity">
5546 <title>PQF Proximity queries</title>
5549 @prox 0 3 1 2 k 2 dylan zimmerman
5551 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5552 distance, ordered, relation, which-code and unit-code, in that
5556 <para>exclusion = 0: the proximity condition must hold</para>
5559 <para>distance = 3: the terms must be three units apart</para>
5563 ordered = 1: they must occur in the order they are specified
5568 relation = 2: lessThanOrEqual (to the distance of 3 units)
5573 which-code is "known", so the standard unit-codes are used
5577 <para>unit-code = 2: word.</para>
5580 So the whole proximity query means that the words
5581 <literal>dylan</literal> and <literal>zimmerman</literal> must
5582 both occur in the record, in that order, differing in position
5583 by three or fewer words (i.e. with two or fewer words between
5584 them.) The query would find "Bob Dylan, aka. Robert
5585 Zimmerman", but not "Bob Dylan, born as Robert Zimmerman"
5586 since the distance in this case is four.
5589 <example id="example.pqf.search.term.type">
5590 <title>PQF specification of search term type</title>
5593 @term string "a UTF-8 string, maybe?"
5597 <example id="example.pqf.mixed.queries">
5598 <title>PQF mixed queries</title>
5601 @or @and bob dylan @set Result-1
5603 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5605 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5607 The last of these examples is a spatial search: in
5608 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5609 >the GILS attribute set</ulink>,
5611 2038 indicates West Bounding Coordinate and
5612 2030 indicates East Bounding Coordinate,
5613 so the query is for areas extending from -114 degrees longitude
5614 to no more than -109 degrees longitude.
5619 <sect2 id="CCL"><title>CCL</title>
5621 Not all users enjoy typing in prefix query structures and numerical
5622 attribute values, even in a minimalistic test client. In the library
5623 world, the more intuitive Common Command Language - CCL (ISO 8777)
5624 has enjoyed some popularity - especially before the widespread
5625 availability of graphical interfaces. It is still useful in
5626 applications where you for some reason or other need to provide a
5627 symbolic language for expressing boolean query structures.
5629 <sect3 id="ccl.syntax">
5630 <title>CCL Syntax</title>
5632 The CCL parser obeys the following grammar for the FIND argument.
5633 The syntax is annotated using lines prefixed by
5634 <literal>--</literal>.
5637 CCL-Find ::= CCL-Find Op Elements
5640 Op ::= "and" | "or" | "not"
5641 -- The above means that Elements are separated by boolean operators.
5643 Elements ::= '(' CCL-Find ')'
5646 | Qualifiers Relation Terms
5647 | Qualifiers Relation '(' CCL-Find ')'
5648 | Qualifiers '=' string '-' string
5649 -- Elements is either a recursive definition, a result set reference, a
5650 -- list of terms, qualifiers followed by terms, qualifiers followed
5651 -- by a recursive definition or qualifiers in a range (lower - upper).
5653 Set ::= 'set' = string
5654 -- Reference to a result set
5656 Terms ::= Terms Prox Term
5658 -- Proximity of terms.
5660 Term ::= Term string
5662 -- This basically means that a term may include a blank
5664 Qualifiers ::= Qualifiers ',' string
5666 -- Qualifiers is a list of strings separated by comma
5668 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5669 -- Relational operators. This really doesn't follow the ISO8777
5673 -- Proximity operator
5676 <example id="example.ccl.queries">
5677 <title>CCL queries</title>
5679 The following queries are all valid:
5690 (dylan and bob) or set=1
5699 Assuming that the qualifiers <literal>ti</literal>
5700 and <literal>au</literal>
5701 and <literal>date</literal> are defined, we may use:
5706 au=(bob dylan and slow train coming)
5708 date>1980 and (ti=((self portrait)))
5712 <sect3 id="ccl.qualifiers">
5713 <title>CCL Qualifiers</title>
5715 Qualifiers are used to direct the search to a particular searchable
5716 index, such as title (ti) and author indexes (au). The CCL standard
5717 itself doesn't specify a particular set of qualifiers, but it does
5718 suggest a few short-hand notations. You can customize the CCL parser
5719 to support a particular set of qualifiers to reflect the current target
5720 profile. Traditionally, a qualifier would map to a particular
5721 use-attribute within the BIB-1 attribute set. It is also
5722 possible to set other attributes, such as the structure
5726 A CCL profile is a set of predefined CCL qualifiers that may be
5727 read from a file or set in the CCL API.
5728 The YAZ client reads its CCL qualifiers from a file named
5729 <filename>default.bib</filename>. There are four types of
5730 lines in a CCL profile: qualifier specification,
5731 qualifier alias, comments and directives.
5733 <sect4 id="ccl.qualifier.specification">
5734 <title>Qualifier specification</title>
5736 A qualifier specification is of the form:
5739 <replaceable>qualifier-name</replaceable>
5740 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5741 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5744 where <replaceable>qualifier-name</replaceable> is the name of the
5745 qualifier to be used (e.g. <literal>ti</literal>),
5746 <replaceable>type</replaceable> is attribute type in the attribute
5747 set (Bib-1 is used if no attribute set is given) and
5748 <replaceable>val</replaceable> is attribute value.
5749 The <replaceable>type</replaceable> can be specified as an
5750 integer, or as a single-letter:
5751 <literal>u</literal> for use,
5752 <literal>r</literal> for relation, <literal>p</literal> for position,
5753 <literal>s</literal> for structure,<literal>t</literal> for truncation,
5754 or <literal>c</literal> for completeness.
5755 The attributes for the special qualifier name <literal>term</literal>
5756 are used when no CCL qualifier is given in a query.
5757 <table id="ccl.common.bib1.attributes">
5758 <title>Common Bib-1 attributes</title>
5760 <colspec colwidth="2*" colname="type"></colspec>
5761 <colspec colwidth="9*" colname="description"></colspec>
5765 <entry>Description</entry>
5770 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5772 Use attribute (1). Common use attributes are
5773 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5774 62 Subject, 1003 Author, 1016 Any. Specify value
5779 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5781 Relation attribute (2). Common values are
5782 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5783 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5787 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5789 Position attribute (3). Values: 1 first in field, 2
5790 first in any subfield, 3 any position in field.
5794 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5796 Structure attribute (4). Values: 1 phrase, 2 word,
5797 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5798 101 name (norm), 102 name (un), 103 structure, 104 urx,
5799 105 free-form-text, 106 document-text, 107 local-number,
5800 108 string, 109 numeric string.
5804 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5806 Truncation attribute (5). Values: 1 right, 2 left,
5807 3 left and right, 100 none, 101 process #, 102 regular-1,
5808 103 regular-2, 104 CCL.
5812 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5814 Completeness attribute (6). Values: 1 incomplete subfield,
5815 2 complete subfield, 3 complete field.
5823 Refer to <xref linkend="bib1"/> or the complete
5824 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5827 It is also possible to specify non-numeric attribute values,
5828 which are used in combination with certain types.
5829 The special combinations are:
5830 <table id="ccl.special.attribute.combos">
5831 <title>Special attribute combos</title>
5833 <colspec colwidth="2*" colname="name"></colspec>
5834 <colspec colwidth="9*" colname="description"></colspec>
5838 <entry>Description</entry>
5843 <entry><literal>s=pw</literal></entry>
5845 The structure is set to either word or phrase depending
5846 on the number of tokens in a term (phrase-word).
5850 <entry><literal>s=al</literal></entry>
5852 Each token in the term is ANDed (and-list).
5853 This does not set the structure at all.
5856 <row><entry><literal>s=ol</literal></entry>
5858 Each token in the term is ORed (or-list).
5859 This does not set the structure at all.
5862 <row><entry><literal>s=ag</literal></entry>
5864 Tokens that appears as phrases (with blank in them) gets
5865 structure phrase attached (4=1). Tokens that appear to be words
5866 gets structure word attached (4=2). Phrases and words are
5867 ANDed. This is a variant of s=al and s=pw, with the main
5868 difference that words are not split (with operator AND)
5869 but instead kept in one RPN token. This facility appeared
5873 <row><entry><literal>s=sl</literal></entry>
5875 Tokens are split into sub-phrases of all combinations - in order.
5876 This facility appeared in YAZ 5.14.0.
5879 <row><entry><literal>r=o</literal></entry>
5881 Allows ranges and the operators greater-than, less-than, ...
5883 This sets Bib-1 relation attribute accordingly (relation
5884 ordered). A query construct is only treated as a range if
5885 dash is used and that is surrounded by white-space. So
5886 <literal>-1980</literal> is treated as term
5887 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5888 If <literal>- 1980</literal> is used, however, that is
5892 <row><entry><literal>r=r</literal></entry>
5894 Similar to <literal>r=o</literal> but assumes that terms
5895 are non-negative (not prefixed with <literal>-</literal>).
5896 Thus, a dash will always be treated as a range.
5897 The construct <literal>1980-1990</literal> is
5898 treated as a range with <literal>r=r</literal> but as a
5899 single term <literal>"1980-1990"</literal> with
5900 <literal>r=o</literal>. The special attribute
5901 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5904 <row><entry><literal>r=omiteq</literal></entry>
5906 This will omit relation=equals (@attr 2=3) when r=o / r=r
5907 is used. This is useful for servers that somehow break
5908 when an explicit relation=equals is used. Omitting the
5909 relation is usually safe because "equals" is the default
5910 behavior. This tweak was added in YAZ version 5.1.2.
5913 <row><entry><literal>t=l</literal></entry>
5915 Allows term to be left-truncated.
5916 If term is of the form <literal>?x</literal>, the resulting
5917 Type-1 term is <literal>x</literal> and truncation is left.
5920 <row><entry><literal>t=r</literal></entry>
5922 Allows term to be right-truncated.
5923 If term is of the form <literal>x?</literal>, the resulting
5924 Type-1 term is <literal>x</literal> and truncation is right.
5927 <row><entry><literal>t=n</literal></entry>
5929 If term is does not include <literal>?</literal>, the
5930 truncation attribute is set to none (100).
5933 <row><entry><literal>t=b</literal></entry>
5935 Allows term to be both left-and-right truncated.
5936 If term is of the form <literal>?x?</literal>, the
5937 resulting term is <literal>x</literal> and trunctation is
5938 set to both left and right.
5941 <row><entry><literal>t=x</literal></entry>
5943 Allows masking anywhere in a term, thus fully supporting
5944 # (mask one character) and ? (zero or more of any).
5945 If masking is used, truncation is set to 102 (regexp-1 in term)
5946 and the term is converted accordingly to a regular expression.
5949 <row><entry><literal>t=z</literal></entry>
5951 Allows masking anywhere in a term, thus fully supporting
5952 # (mask one character) and ? (zero or more of any).
5953 If masking is used, truncation is set to 104 (Z39.58 in term)
5954 and the term is converted accordingly to Z39.58 masking term -
5955 actually the same truncation as CCL itself.
5962 <example id="example.ccl.profile">
5963 <title>CCL profile</title>
5965 Consider the following definition:
5975 <literal>ti</literal> and <literal>au</literal> both set
5976 structure attribute to phrase (s=1).
5977 <literal>ti</literal>
5978 sets the use-attribute to 4. <literal>au</literal> sets the
5980 When no qualifiers are used in the query, the structure-attribute is
5981 set to free-form-text (105) (rule for <literal>term</literal>).
5982 The <literal>date</literal> sets the relation attribute to
5983 the relation used in the CCL query and sets the use attribute
5987 You can combine attributes. To Search for "ranked title" you
5990 ti,ranked=knuth computer
5992 which will set relation=ranked, use=title, structure=phrase.
5999 is a valid query. But
6007 <sect4 id="ccl.qualifier.alias">
6008 <title>Qualifier alias</title>
6010 A qualifier alias is of the form:
6013 <replaceable>q</replaceable>
6014 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
6017 which declares <replaceable>q</replaceable> to
6018 be an alias for <replaceable>q1</replaceable>,
6019 <replaceable>q2</replaceable>... such that the CCL
6020 query <replaceable>q=x</replaceable> is equivalent to
6021 <replaceable>q1=x or q2=x or ...</replaceable>.
6024 <sect4 id="ccl.comments">
6025 <title>Comments</title>
6027 Lines with white space or lines that begin with
6028 character <literal>#</literal> are treated as comments.
6031 <sect4 id="ccl.directives">
6032 <title>Directives</title>
6034 Directive specifications takes the form
6036 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
6038 <table id="ccl.directives.table">
6039 <title>CCL directives</title>
6041 <colspec colwidth="2*" colname="name"></colspec>
6042 <colspec colwidth="8*" colname="description"></colspec>
6043 <colspec colwidth="1*" colname="default"></colspec>
6047 <entry>Description</entry>
6048 <entry>Default</entry>
6053 <entry>truncation</entry>
6054 <entry>Truncation character</entry>
6055 <entry><literal>?</literal></entry>
6059 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
6060 <entry><literal>#</literal></entry>
6063 <entry>field</entry>
6064 <entry>Specifies how multiple fields are to be
6065 combined. There are two modes: <literal>or</literal>:
6066 multiple qualifier fields are ORed,
6067 <literal>merge</literal>: attributes for the qualifier
6068 fields are merged and assigned to one term.
6070 <entry><literal>merge</literal></entry>
6074 <entry>Specifies if CCL operators and qualifiers should be
6075 compared with case sensitivity or not. Specify 1 for
6076 case sensitive; 0 for case insensitive.</entry>
6077 <entry><literal>1</literal></entry>
6081 <entry>Specifies token for CCL operator AND.</entry>
6082 <entry><literal>and</literal></entry>
6086 <entry>Specifies token for CCL operator OR.</entry>
6087 <entry><literal>or</literal></entry>
6091 <entry>Specifies token for CCL operator NOT.</entry>
6092 <entry><literal>not</literal></entry>
6096 <entry>Specifies token for CCL operator SET.</entry>
6097 <entry><literal>set</literal></entry>
6104 <sect3 id="ccl.api">
6105 <title>CCL API</title>
6107 All public definitions can be found in the header file
6108 <filename>ccl.h</filename>. A profile identifier is of type
6109 <literal>CCL_bibset</literal>. A profile must be created with the call
6110 to the function <function>ccl_qual_mk</function> which returns a profile
6111 handle of type <literal>CCL_bibset</literal>.
6114 To read a file containing qualifier definitions the function
6115 <function>ccl_qual_file</function> may be convenient. This function
6116 takes an already opened <literal>FILE</literal> handle pointer as
6117 argument along with a <literal>CCL_bibset</literal> handle.
6120 To parse a simple string with a FIND query use the function
6123 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
6124 int *error, int *pos);
6127 which takes the CCL profile (<literal>bibset</literal>) and query
6128 (<literal>str</literal>) as input. Upon successful completion the RPN
6129 tree is returned. If an error occurs, such as a syntax error, the integer
6130 pointed to by <literal>error</literal> holds the error code and
6131 <literal>pos</literal> holds the offset inside query string in which
6135 An English representation of the error may be obtained by calling
6136 the <literal>ccl_err_msg</literal> function. The error codes are
6137 listed in <filename>ccl.h</filename>.
6140 To convert the CCL RPN tree (type
6141 <literal>struct ccl_rpn_node *</literal>)
6142 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
6143 must be used. This function which is part of YAZ is implemented in
6144 <filename>yaz-ccl.c</filename>.
6145 After calling this function the CCL RPN tree is probably no longer
6146 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
6149 A CCL profile may be destroyed by calling the
6150 <function>ccl_qual_rm</function> function.
6153 The token names for the CCL operators may be changed by setting the
6154 globals (all type <literal>char *</literal>)
6155 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
6156 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
6157 An operator may have aliases, i.e. there may be more than one name for
6158 the operator. To do this, separate each alias with a space character.
6165 <ulink url="&url.cql;">CQL</ulink>
6166 - Common Query Language - was defined for the
6167 <ulink url="&url.sru;">SRU</ulink> protocol.
6168 In many ways CQL has a similar syntax to CCL.
6169 The objective of CQL is different. Where CCL aims to be
6170 an end-user language, CQL is <emphasis>the</emphasis> protocol
6171 query language for SRU.
6175 If you are new to CQL, read the
6176 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6180 The CQL parser in &yaz; provides the following:
6184 It parses and validates a CQL query.
6189 It generates a C structure that allows you to convert
6190 a CQL query to some other query language, such as SQL.
6195 The parser converts a valid CQL query to PQF, thus providing a
6196 way to use CQL for both SRU servers and Z39.50 targets at the
6202 The parser converts CQL to XCQL.
6203 XCQL is an XML representation of CQL.
6204 XCQL is part of the SRU specification. However, since SRU
6205 supports CQL only, we don't expect XCQL to be widely used.
6206 Furthermore, CQL has the advantage over XCQL that it is
6212 <sect3 id="cql.parsing">
6213 <title>CQL parsing</title>
6215 A CQL parser is represented by the <literal>CQL_parser</literal>
6216 handle. Its contents should be considered &yaz; internal (private).
6218 #include <yaz/cql.h>
6220 typedef struct cql_parser *CQL_parser;
6222 CQL_parser cql_parser_create(void);
6223 void cql_parser_destroy(CQL_parser cp);
6225 A parser is created by <function>cql_parser_create</function> and
6226 is destroyed by <function>cql_parser_destroy</function>.
6229 To parse a CQL query string, the following function
6232 int cql_parser_string(CQL_parser cp, const char *str);
6234 A CQL query is parsed by the <function>cql_parser_string</function>
6235 which takes a query <parameter>str</parameter>.
6236 If the query was valid (no syntax errors), then zero is returned;
6237 otherwise -1 is returned to indicate a syntax error.
6241 int cql_parser_stream(CQL_parser cp,
6242 int (*getbyte)(void *client_data),
6243 void (*ungetbyte)(int b, void *client_data),
6246 int cql_parser_stdio(CQL_parser cp, FILE *f);
6248 The functions <function>cql_parser_stream</function> and
6249 <function>cql_parser_stdio</function> parse a CQL query
6250 - just like <function>cql_parser_string</function>.
6251 The only difference is that the CQL query can be
6252 fed to the parser in different ways.
6253 The <function>cql_parser_stream</function> uses a generic
6254 byte stream as input. The <function>cql_parser_stdio</function>
6255 uses a <literal>FILE</literal> handle which is opened for reading.
6258 <sect3 id="cql.tree">
6259 <title>CQL tree</title>
6261 If the query string is valid, the CQL parser
6262 generates a tree representing the structure of the
6267 struct cql_node *cql_parser_result(CQL_parser cp);
6269 <function>cql_parser_result</function> returns
6270 a pointer to the root node of the resulting tree.
6273 Each node in a CQL tree is represented by a
6274 <literal>struct cql_node</literal>.
6275 It is defined as follows:
6277 #define CQL_NODE_ST 1
6278 #define CQL_NODE_BOOL 2
6279 #define CQL_NODE_SORT 3
6289 struct cql_node *modifiers;
6293 struct cql_node *left;
6294 struct cql_node *right;
6295 struct cql_node *modifiers;
6299 struct cql_node *next;
6300 struct cql_node *modifiers;
6301 struct cql_node *search;
6306 There are three node types: search term (ST), boolean (BOOL)
6308 A modifier is treated as a search term too.
6311 The search term node has five members:
6315 <literal>index</literal>: index for search term.
6316 If an index is unspecified for a search term,
6317 <literal>index</literal> will be NULL.
6322 <literal>index_uri</literal>: index URi for search term
6323 or NULL if none could be resolved for the index.
6328 <literal>term</literal>: the search term itself.
6333 <literal>relation</literal>: relation for search term.
6338 <literal>relation_uri</literal>: relation URI for search term.
6343 <literal>modifiers</literal>: relation modifiers for search
6344 term. The <literal>modifiers</literal> list itself of cql_nodes
6345 each of type <literal>ST</literal>.
6351 The boolean node represents <literal>and</literal>,
6352 <literal>or</literal>, <literal>not</literal> +
6357 <literal>left</literal> and <literal>right</literal>: left
6358 - and right operand respectively.
6363 <literal>modifiers</literal>: proximity arguments.
6369 The sort node represents both the SORTBY clause.
6372 <sect3 id="cql.to.pqf">
6373 <title>CQL to PQF conversion</title>
6375 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6376 that the resulting RPN depends on the Z39.50 target
6377 capabilities (combinations of supported attributes).
6378 In addition, the CQL and SRU operates on index prefixes
6379 (URI or strings), whereas the RPN uses Object Identifiers
6383 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6384 type. It represents a particular mapping between CQL and RPN.
6385 This handle is created and destroyed by the functions:
6387 cql_transform_t cql_transform_open_FILE (FILE *f);
6388 cql_transform_t cql_transform_open_fname(const char *fname);
6389 void cql_transform_close(cql_transform_t ct);
6391 The first two functions create a tranformation handle from
6392 either an already open FILE or from a filename respectively.
6395 The handle is destroyed by <function>cql_transform_close</function>
6396 in which case no further reference of the handle is allowed.
6399 When a <literal>cql_transform_t</literal> handle has been created
6400 you can convert to RPN.
6402 int cql_transform_buf(cql_transform_t ct,
6403 struct cql_node *cn, char *out, int max);
6405 This function converts the CQL tree <literal>cn</literal>
6406 using handle <literal>ct</literal>.
6407 For the resulting PQF, you supply a buffer <literal>out</literal>
6408 which must be able to hold at at least <literal>max</literal>
6412 If conversion failed, <function>cql_transform_buf</function>
6413 returns a non-zero SRU error code; otherwise zero is returned
6414 (conversion successful). The meanings of the numeric error
6415 codes are listed in the SRU specification somewhere (no
6416 direct link anymore).
6419 If conversion fails, more information can be obtained by calling
6421 int cql_transform_error(cql_transform_t ct, char **addinfop);
6423 This function returns the most recently returned numeric
6424 error-code and sets the string-pointer at
6425 <literal>*addinfop</literal> to point to a string containing
6426 additional information about the error that occurred: for
6427 example, if the error code is 15 ("Illegal or unsupported context
6428 set"), the additional information is the name of the requested
6429 context set that was not recognised.
6432 The SRU error-codes may be translated into brief human-readable
6433 error messages using
6435 const char *cql_strerror(int code);
6439 If you wish to be able to produce a PQF result in a different
6440 way, there are two alternatives.
6442 void cql_transform_pr(cql_transform_t ct,
6443 struct cql_node *cn,
6444 void (*pr)(const char *buf, void *client_data),
6447 int cql_transform_FILE(cql_transform_t ct,
6448 struct cql_node *cn, FILE *f);
6450 The former function produces output to a user-defined
6451 output stream. The latter writes the result to an already
6452 open <literal>FILE</literal>.
6455 <sect3 id="cql.to.rpn">
6456 <title>Specification of CQL to RPN mappings</title>
6458 The file supplied to functions
6459 <function>cql_transform_open_FILE</function>,
6460 <function>cql_transform_open_fname</function> follows
6461 a structure found in many Unix utilities.
6462 It consists of mapping specifications - one per line.
6463 Lines starting with <literal>#</literal> are ignored (comments).
6466 Each line is of the form
6468 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6472 An RPN pattern is a simple attribute list. Each attribute pair
6475 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6477 The attribute <replaceable>set</replaceable> is optional.
6478 The <replaceable>type</replaceable> is the attribute type,
6479 <replaceable>value</replaceable> the attribute value.
6482 The character <literal>*</literal> (asterisk) has special meaning
6483 when used in the RPN pattern.
6484 Each occurrence of <literal>*</literal> is substituted with the
6485 CQL matching name (index, relation, qualifier etc).
6486 This facility can be used to copy a CQL name verbatim to the RPN result.
6489 The following CQL patterns are recognized:
6493 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6497 This pattern is invoked when a CQL index, such as
6498 dc.title is converted. <replaceable>set</replaceable>
6499 and <replaceable>name</replaceable> are the context set and index
6501 Typically, the RPN specifies an equivalent use attribute.
6504 For terms not bound by an index, the pattern
6505 <literal>index.cql.serverChoice</literal> is used.
6506 Here, the prefix <literal>cql</literal> is defined as
6507 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6508 If this pattern is not defined, the mapping will fail.
6512 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6513 is used when no other index pattern is matched.
6519 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6524 For backwards compatibility, this is recognised as a synonym of
6525 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6531 <literal>relation.</literal><replaceable>relation</replaceable>
6535 This pattern specifies how a CQL relation is mapped to RPN.
6536 The <replaceable>pattern</replaceable> is name of relation
6537 operator. Since <literal>=</literal> is used as
6538 separator between CQL pattern and RPN, CQL relations
6539 including <literal>=</literal> cannot be
6540 used directly. To avoid a conflict, the names
6541 <literal>ge</literal>,
6542 <literal>eq</literal>,
6543 <literal>le</literal>,
6544 must be used for CQL operators, greater-than-or-equal,
6545 equal, less-than-or-equal respectively.
6546 The RPN pattern is supposed to include a relation attribute.
6549 For terms not bound by a relation, the pattern
6550 <literal>relation.scr</literal> is used. If the pattern
6551 is not defined, the mapping will fail.
6554 The special pattern, <literal>relation.*</literal> is used
6555 when no other relation pattern is matched.
6561 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6565 This pattern specifies how a CQL relation modifier is mapped to RPN.
6566 The RPN pattern is usually a relation attribute.
6572 <literal>structure.</literal><replaceable>type</replaceable>
6576 This pattern specifies how a CQL structure is mapped to RPN.
6577 Note that this CQL pattern is somewhat similar to
6578 CQL pattern <literal>relation</literal>.
6579 The <replaceable>type</replaceable> is a CQL relation.
6582 The pattern, <literal>structure.*</literal> is used
6583 when no other structure pattern is matched.
6584 Usually, the RPN equivalent specifies a structure attribute.
6590 <literal>position.</literal><replaceable>type</replaceable>
6594 This pattern specifies how the anchor (position) of
6595 CQL is mapped to RPN.
6596 The <replaceable>type</replaceable> is one
6597 of <literal>first</literal>, <literal>any</literal>,
6598 <literal>last</literal>, <literal>firstAndLast</literal>.
6601 The pattern, <literal>position.*</literal> is used
6602 when no other position pattern is matched.
6608 <literal>set.</literal><replaceable>prefix</replaceable>
6612 This specification defines a CQL context set for a given prefix.
6613 The value on the right hand side is the URI for the set -
6614 <emphasis>not</emphasis> RPN. All prefixes used in
6615 index patterns must be defined this way.
6621 <literal>set</literal>
6625 This specification defines a default CQL context set for index names.
6626 The value on the right hand side is the URI for the set.
6632 <example id="example.cql.to.rpn.mapping">
6633 <title>CQL to RPN mapping file</title>
6635 This simple file defines two context sets, three indexes and three
6636 relations, a position pattern and a default structure.
6638 <programlisting><![CDATA[
6639 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6640 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6642 index.cql.serverChoice = 1=1016
6643 index.dc.title = 1=4
6644 index.dc.subject = 1=21
6650 position.any = 3=3 6=1
6656 With the mappings above, the CQL query
6660 is converted to the PQF:
6662 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6664 by rules <literal>index.cql.serverChoice</literal>,
6665 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6666 <literal>position.any</literal>.
6673 is rejected, since <literal>position.right</literal> is
6679 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6683 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6687 <example id="example.cql.to.rpn.string">
6688 <title>CQL to RPN string attributes</title>
6690 In this example we allow any index to be passed to RPN as
6693 <programlisting><![CDATA[
6694 # Identifiers for prefixes used in this file. (index.*)
6695 set.cql = info:srw/cql-context-set/1/cql-v1.1
6696 set.rpn = http://bogus/rpn
6697 set = http://bogus/rpn
6699 # The default index when none is specified by the query
6700 index.cql.serverChoice = 1=any
6709 The <literal>http://bogus/rpn</literal> context set is also the default
6710 so we can make queries such as
6714 which is converted to
6716 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6720 <example id="example.cql.to.rpn.bathprofile">
6721 <title>CQL to RPN using Bath Profile</title>
6723 The file <filename>etc/pqf.properties</filename> has mappings from
6724 the Bath Profile and Dublin Core to RPN.
6725 If YAZ is installed as a package it's usually located
6726 in <filename>/usr/share/yaz/etc</filename> and part of the
6727 development package, such as <literal>libyaz-dev</literal>.
6731 <sect3 id="cql.xcql">
6732 <title>CQL to XCQL conversion</title>
6734 Conversion from CQL to XCQL is trivial and does not
6735 require a mapping to be defined.
6736 There are three functions to choose from depending on the
6737 way you wish to store the resulting output (XML buffer
6740 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6741 void cql_to_xml(struct cql_node *cn,
6742 void (*pr)(const char *buf, void *client_data),
6744 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6746 Function <function>cql_to_xml_buf</function> converts
6747 to XCQL and stores the result in a user-supplied buffer of a given
6751 <function>cql_to_xml</function> writes the result in
6752 a user-defined output stream.
6753 <function>cql_to_xml_stdio</function> writes to a
6757 <sect3 id="rpn.to.cql">
6758 <title>PQF to CQL conversion</title>
6760 Conversion from PQF to CQL is offered by the two functions shown
6761 below. The former uses a generic stream for result. The latter
6762 puts result in a WRBUF (string container).
6764 #include <yaz/rpn2cql.h>
6766 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6767 void (*pr)(const char *buf, void *client_data),
6771 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6775 The configuration is the same as used in CQL to PQF conversions.
6780 <sect1 id="tools.oid">
6781 <title>Object Identifiers</title>
6783 The basic YAZ representation of an OID is an array of integers,
6784 terminated with the value -1. This integer is of type
6785 <literal>Odr_oid</literal>.
6788 Fundamental OID operations and the type <literal>Odr_oid</literal>
6789 are defined in <filename>yaz/oid_util.h</filename>.
6792 An OID can either be declared as a automatic variable or it can
6793 be allocated using the memory utilities or ODR/NMEM. It's
6794 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6796 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6798 We can create an OID for the Bib-1 attribute set with:
6800 Odr_oid bib1[OID_SIZE];
6812 And OID may also be filled from a string-based representation using
6813 dots (.). This is achieved by the function
6815 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6817 This functions returns 0 if name could be converted; -1 otherwise.
6819 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6821 We can fill the Bib-1 attribute set OID more easily with:
6823 Odr_oid bib1[OID_SIZE];
6824 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6829 We can also allocate an OID dynamically on an ODR stream with:
6831 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6833 This creates an OID from a string-based representation using dots.
6834 This function take an &odr; stream as parameter. This stream is used to
6835 allocate memory for the data elements, which is released on a
6836 subsequent call to <function>odr_reset()</function> on that stream.
6838 <example id="tools.oid.bib1.3">
6839 <title>Using odr_getoidbystr</title>
6841 We can create an OID for the Bib-1 attribute set with:
6843 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6850 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6852 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6853 converts an OID to the string-based representation using dots.
6854 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6855 string and must be at least <literal>OID_STR_MAX</literal> in size.
6858 OIDs can be copied with <function>oid_oidcpy</function> which takes
6859 two OID lists as arguments. Alternatively, an OID copy can be allocated
6860 on an ODR stream with:
6862 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6866 OIDs can be compared with <function>oid_oidcmp</function> which returns
6867 zero if the two OIDs provided are identical; non-zero otherwise.
6869 <sect2 id="tools.oid.database">
6870 <title>OID database</title>
6872 From YAZ version 3 and later, the oident system has been replaced
6873 by an OID database. OID database is a misnomer .. the old odient
6874 system was also a database.
6877 The OID database is really just a map between named Object Identifiers
6878 (string) and their OID raw equivalents. Most operations either
6879 convert from string to OID or other way around.
6882 Unfortunately, whenever we supply a string we must also specify the
6883 <emphasis>OID class</emphasis>. The class is necessary because some
6884 strings correspond to multiple OIDs. An example of such a string is
6885 <literal>Bib-1</literal> which may either be an attribute-set
6886 or a diagnostic-set.
6889 Applications using the YAZ database should include
6890 <filename>yaz/oid_db.h</filename>.
6893 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6894 Actually that's a pointer. You need not deal with that.
6895 YAZ has a built-in database which can be considered "constant" for
6897 We can get hold of that by using function <function>yaz_oid_std</function>.
6900 All functions with prefix <function>yaz_string_to_oid</function>
6901 converts from class + string to OID. We have variants of this
6902 operation due to different memory allocation strategies.
6905 All functions with prefix
6906 <function>yaz_oid_to_string</function> converts from OID to string
6909 <example id="tools.oid.bib1.4">
6910 <title>Create OID with YAZ DB</title>
6912 We can create an OID for the Bib-1 attribute set on the ODR stream
6916 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6918 This is more complex than using <function>odr_getoidbystr</function>.
6919 You would only use <function>yaz_string_to_oid_odr</function> when the
6920 string (here Bib-1) is supplied by a user or configuration.
6924 <sect2 id="tools.oid.std">
6925 <title>Standard OIDs</title>
6927 All the object identifers in the standard OID database as returned
6928 by <function>yaz_oid_std</function> can be referenced directly in a
6929 program as a constant OID.
6930 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6931 followed by OID class (lowercase) - then by OID name (normalized and
6935 See <xref linkend="list-oids"/> for list of all object identifiers
6937 These are declared in <filename>yaz/oid_std.h</filename> but are
6938 included by <filename>yaz/oid_db.h</filename> as well.
6940 <example id="tools.oid.bib1.5">
6941 <title>Use a built-in OID</title>
6943 We can allocate our own OID filled with the constant OID for
6946 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6952 <sect1 id="tools.nmem">
6953 <title>Nibble Memory</title>
6955 Sometimes when you need to allocate and construct a large,
6956 interconnected complex of structures, it can be a bit of a pain to
6957 release the associated memory again. For the structures describing the
6958 Z39.50 PDUs and related structures, it is convenient to use the
6959 memory-management system of the &odr; subsystem (see
6960 <xref linkend="odr.use"/>). However, in some circumstances
6961 where you might otherwise benefit from using a simple nibble-memory
6962 management system, it may be impractical to use
6963 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6964 For this purpose, the memory manager which also supports the &odr;
6965 streams is made available in the NMEM module. The external interface
6966 to this module is given in the <filename>nmem.h</filename> file.
6969 The following prototypes are given:
6972 NMEM nmem_create(void);
6973 void nmem_destroy(NMEM n);
6974 void *nmem_malloc(NMEM n, size_t size);
6975 void nmem_reset(NMEM n);
6976 size_t nmem_total(NMEM n);
6977 void nmem_init(void);
6978 void nmem_exit(void);
6981 The <function>nmem_create()</function> function returns a pointer to a
6982 memory control handle, which can be released again by
6983 <function>nmem_destroy()</function> when no longer needed.
6984 The function <function>nmem_malloc()</function> allocates a block of
6985 memory of the requested size. A call to <function>nmem_reset()</function>
6986 or <function>nmem_destroy()</function> will release all memory allocated
6987 on the handle since it was created (or since the last call to
6988 <function>nmem_reset()</function>. The function
6989 <function>nmem_total()</function> returns the number of bytes currently
6990 allocated on the handle.
6993 The nibble-memory pool is shared amongst threads. POSIX
6994 mutex'es and WIN32 Critical sections are introduced to keep the
6995 module thread safe. Function <function>nmem_init()</function>
6996 initializes the nibble-memory library and it is called automatically
6997 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6998 function <function>DllMain</function> to achieve this. You should
6999 <emphasis>not</emphasis> call <function>nmem_init</function> or
7000 <function>nmem_exit</function> unless you're absolute sure what
7001 you're doing. Note that in previous &yaz; versions you'd have to call
7002 <function>nmem_init</function> yourself.
7005 <sect1 id="tools.log">
7008 &yaz; has evolved a fairly complex log system which should be useful both
7009 for debugging &yaz; itself, debugging applications that use &yaz;, and for
7010 production use of those applications.
7013 The log functions are declared in header <filename>yaz/log.h</filename>
7014 and implemented in <filename>src/log.c</filename>.
7015 Due to name clash with syslog and some math utilities the logging
7016 interface has been modified as of YAZ 2.0.29. The obsolete interface
7017 is still available in header file <filename>yaz/log.h</filename>.
7018 The key points of the interface are:
7021 void yaz_log(int level, const char *fmt, ...)
7022 void yaz_log_init(int level, const char *prefix, const char *name);
7023 void yaz_log_init_file(const char *fname);
7024 void yaz_log_init_level(int level);
7025 void yaz_log_init_prefix(const char *prefix);
7026 void yaz_log_time_format(const char *fmt);
7027 void yaz_log_init_max_size(int mx);
7029 int yaz_log_mask_str(const char *str);
7030 int yaz_log_module_level(const char *name);
7033 The reason for the whole log module is the <function>yaz_log</function>
7034 function. It takes a bitmask indicating the log levels, a
7035 <literal>printf</literal>-like format string, and a variable number of
7039 The <literal>log level</literal> is a bit mask, that says on which level(s)
7040 the log entry should be made, and optionally set some behaviour of the
7041 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
7042 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
7043 that modify the way the log entry is written:<literal>YLOG_ERRNO,
7044 YLOG_NOTIME, YLOG_FLUSH</literal>.
7045 Most of the rest of the bits are deprecated, and should not be used. Use
7046 the dynamic log levels instead.
7049 Applications that use &yaz;, should not use the LOG_LOG for ordinary
7050 messages, but should make use of the dynamic loglevel system. This consists
7051 of two parts, defining the loglevel and checking it.
7054 To define the log levels, the (main) program should pass a string to
7055 <function>yaz_log_mask_str</function> to define which log levels are to be
7056 logged. This string should be a comma-separated list of log level names,
7057 and can contain both hard-coded names and dynamic ones. The log level
7058 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
7059 for each word it meets, unless the word starts with a '-', in which case it
7060 clears the bit. If the string <literal>'none'</literal> is found,
7061 all bits are cleared. Typically this string comes from the command-line,
7062 often identified by <literal>-v</literal>. The
7063 <function>yaz_log_mask_str</function> returns a log level that should be
7064 passed to <function>yaz_log_init_level</function> for it to take effect.
7067 Each module should check what log bits should be used, by calling
7068 <function>yaz_log_module_level</function> with a suitable name for the
7069 module. The name is cleared of a preceding path and an extension, if any,
7070 so it is quite possible to use <literal>__FILE__</literal> for it. If the
7071 name has been passed to <function>yaz_log_mask_str</function>, the routine
7072 returns a non-zero bitmask, which should then be used in consequent calls
7073 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
7074 yaz_log, in time-critical places, or when the log entry would take time
7078 Yaz uses the following dynamic log levels:
7079 <literal>server, session, request, requestdetail</literal> for the server
7081 <literal>zoom</literal> for the zoom client api.
7082 <literal>ztest</literal> for the simple test server.
7083 <literal>malloc, nmem, odr, eventl</literal> for internal
7084 debugging of yaz itself.
7085 Of course, any program using yaz is welcome to define as many new
7089 By default the log is written to stderr, but this can be changed by a call
7090 to <function>yaz_log_init_file</function> or
7091 <function>yaz_log_init</function>. If the log is directed to a file, the
7092 file size is checked at every write, and if it exceeds the limit given in
7093 <function>yaz_log_init_max_size</function>, the log is rotated. The
7094 rotation keeps one old version (with a <literal>.1</literal> appended to
7095 the name). The size defaults to 1GB. Setting it to zero will disable the
7099 A typical yaz-log looks like this
7100 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
7101 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
7102 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
7103 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
7104 13:24:13-23/11 yaz-ztest(1) [request] Close OK
7107 The log entries start with a time stamp. This can be omitted by setting the
7108 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
7109 can be hoped to produce identical log files, that are easy to diff. The
7110 format of the time stamp can be set with
7111 <function>yaz_log_time_format</function>, which takes a format string just
7112 like <function>strftime</function>.
7115 Next in a log line comes the prefix, often the name of the program. For
7116 yaz-based servers, it can also contain the session number. Then
7117 comes one or more logbits in square brackets, depending on the logging
7118 level set by <function>yaz_log_init_level</function> and the loglevel
7119 passed to <function>yaz_log_init_level</function>. Finally comes the format
7120 string and additional values passed to <function>yaz_log</function>
7123 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
7124 <literal>loglevel</literal>, will log all the log-level affecting
7125 operations. This can come in handy if you need to know what other log
7126 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
7129 The log system is almost independent of the rest of &yaz;, the only
7130 important dependence is of <filename>nmem</filename>, and that only for
7131 using the semaphore definition there.
7134 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
7135 the same time, the log bit names were changed from
7136 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
7137 to avoid collision with <filename>syslog.h</filename>.
7143 YAZ provides a fast utility for working with MARC records.
7144 Early versions of the MARC utility only allowed decoding of ISO2709.
7145 Today the utility may both encode - and decode to a variety of formats.
7148 #include <yaz/marcdisp.h>
7150 /* create handler */
7151 yaz_marc_t yaz_marc_create(void);
7153 void yaz_marc_destroy(yaz_marc_t mt);
7155 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
7156 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
7157 #define YAZ_MARC_LINE 0
7158 #define YAZ_MARC_SIMPLEXML 1
7159 #define YAZ_MARC_OAIMARC 2
7160 #define YAZ_MARC_MARCXML 3
7161 #define YAZ_MARC_ISO2709 4
7162 #define YAZ_MARC_XCHANGE 5
7163 #define YAZ_MARC_CHECK 6
7164 #define YAZ_MARC_TURBOMARC 7
7165 #define YAZ_MARC_JSON 8
7167 /* supply iconv handle for character set conversion .. */
7168 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
7170 /* set debug level, 0=none, 1=more, 2=even more, .. */
7171 void yaz_marc_debug(yaz_marc_t mt, int level);
7173 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7174 On success, result in *result with size *rsize. */
7175 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7176 const char **result, size_t *rsize);
7178 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7179 On success, result in WRBUF */
7180 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7181 int bsize, WRBUF wrbuf);
7186 The synopsis is just a basic subset of all functionality. Refer
7187 to the actual header file <filename>marcdisp.h</filename> for
7192 A MARC conversion handle must be created by using
7193 <function>yaz_marc_create</function> and destroyed
7194 by calling <function>yaz_marc_destroy</function>.
7197 All other functions operate on a <literal>yaz_marc_t</literal> handle.
7198 The output is specified by a call to <function>yaz_marc_xml</function>.
7199 The <literal>xmlmode</literal> must be one of
7202 <term>YAZ_MARC_LINE</term>
7205 A simple line-by-line format suitable for display but not
7206 recommended for further (machine) processing.
7211 <term>YAZ_MARC_MARCXML</term>
7214 <ulink url="&url.marcxml;">MARCXML</ulink>.
7219 <term>YAZ_MARC_ISO2709</term>
7222 ISO2709 (sometimes just referred to as "MARC").
7227 <term>YAZ_MARC_XCHANGE</term>
7230 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7235 <term>YAZ_MARC_CHECK</term>
7238 Pseudo format for validation only. Does not generate
7239 any real output except diagnostics.
7244 <term>YAZ_MARC_TURBOMARC</term>
7247 XML format with same semantics as MARCXML but more compact
7248 and geared towards fast processing with XSLT. Refer to
7249 <xref linkend="tools.turbomarc"/> for more information.
7254 <term>YAZ_MARC_JSON</term>
7257 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink> format.
7264 The actual conversion functions are
7265 <function>yaz_marc_decode_buf</function> and
7266 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7267 a MARC record. The former function operates on simple buffers, and
7268 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7271 <example id="example.marc.display">
7272 <title>Display of MARC record</title>
7274 The following program snippet illustrates how the MARC API may
7275 be used to convert a MARC record to the line-by-line format:
7276 <programlisting><![CDATA[
7277 void print_marc(const char *marc_buf, int marc_buf_size)
7279 char *result; /* for result buf */
7280 size_t result_len; /* for size of result */
7281 yaz_marc_t mt = yaz_marc_create();
7282 yaz_marc_xml(mt, YAZ_MARC_LINE);
7283 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7284 &result, &result_len);
7285 fwrite(result, result_len, 1, stdout);
7286 yaz_marc_destroy(mt); /* note that result is now freed... */
7292 <sect2 id="tools.turbomarc">
7293 <title>TurboMARC</title>
7295 TurboMARC is yet another XML encoding of a MARC record. The format
7296 was designed for fast processing with XSLT.
7300 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7301 representation. This conversion mostly checks the tag of a MARC field
7302 to determine the basic rules in the conversion. This check is
7303 costly when that tag is encoded as an attribute in MARCXML.
7304 By having the tag value as the element instead, makes processing
7305 many times faster (at least for Libxslt).
7308 TurboMARC is encoded as follows:
7312 Record elements is part of namespace
7313 "<literal>http://www.indexdata.com/turbomarc</literal>".
7318 A record is enclosed in element <literal>r</literal>.
7323 A collection of records is enclosed in element
7324 <literal>collection</literal>.
7329 The leader is encoded as element <literal>l</literal> with the
7330 leader content as its (text) value.
7335 A control field is encoded as element <literal>c</literal> concatenated
7336 with the tag value of the control field if the tag value
7337 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7338 If the tag value does not match the regular expression
7339 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7340 as element <literal>c</literal> and attribute <literal>code</literal>
7341 will hold the tag value.
7342 This rule ensures that in the rare cases where a tag value might
7343 result in a non-well-formed XML, then YAZ will encode it as a coded attribute
7347 The control field content is the text value of this element.
7348 Indicators are encoded as attribute names
7349 <literal>i1</literal>, <literal>i2</literal>, etc. and
7350 corresponding values for each indicator.
7355 A data field is encoded as element <literal>d</literal> concatenated
7356 with the tag value of the data field or using the attribute
7357 <literal>code</literal> as described in the rules for control fields.
7358 The children of the data field element are subfield elements.
7359 Each subfield element is encoded as <literal>s</literal>
7360 concatenated with the sub field code.
7361 The text of the subfield element is the contents of the subfield.
7362 Indicators are encoded as attributes for the data field element, similar
7363 to the encoding for control fields.
7370 <sect1 id="tools.retrieval">
7371 <title>Retrieval Facility</title>
7373 YAZ version 2.1.20 or later includes a Retrieval facility tool
7374 which allows a SRU/Z39.50 to describe itself and perform record
7375 conversions. The idea is the following:
7379 An SRU/Z39.50 client sends a retrieval request which includes
7380 a combination of the following parameters: syntax (format),
7381 schema (or element set name).
7386 The retrieval facility is invoked with parameters in a
7387 server/proxy. The retrieval facility matches the parameters a set of
7388 "supported" retrieval types.
7389 If there is no match, the retrieval signals an error
7390 (syntax and / or schema not supported).
7395 For a successful match, the backend is invoked with the same
7396 or altered retrieval parameters (syntax, schema). If
7397 a record is received from the backend, it is converted to the
7398 frontend name / syntax.
7403 The resulting record is sent back the client and tagged with
7404 the frontend syntax / schema.
7410 The Retrieval facility is driven by an XML configuration. The
7411 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7412 should be easy to generate both of them from the XML configuration.
7413 (Unfortunately the two versions
7414 of ZeeRex differ substantially in this regard.)
7416 <sect2 id="tools.retrieval.format">
7417 <title>Retrieval XML format</title>
7419 All elements should be covered by namespace
7420 <literal>http://indexdata.com/yaz</literal> .
7421 The root element node must be <literal>retrievalinfo</literal>.
7424 The <literal>retrievalinfo</literal> must include one or
7425 more <literal>retrieval</literal> elements. Each
7426 <literal>retrieval</literal> defines specific combination of
7427 syntax, name and identifier supported by this retrieval service.
7430 The <literal>retrieval</literal> element may include any of the
7431 following attributes:
7433 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7436 Defines the record syntax. Possible values is any
7437 of the names defined in YAZ' OID database or a raw
7442 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7445 Defines the name of the retrieval format. This can be
7446 any string. For SRU, the value is equivalent to schema (short-hand);
7447 for Z39.50 it's equivalent to simple element set name.
7448 For YAZ 3.0.24 and later this name may be specified as a glob
7449 expression with operators
7450 <literal>*</literal> and <literal>?</literal>.
7454 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7457 Defines the URI schema name of the retrieval format. This can be
7458 any string. For SRU, the value is equivalent to URI schema.
7459 For Z39.50, there is no equivalent.
7466 The <literal>retrieval</literal> may include one
7467 <literal>backend</literal> element. If a <literal>backend</literal>
7468 element is given, it specifies how the records are retrieved by
7469 some backend and how the records are converted from the backend to
7473 The attributes, <literal>name</literal> and <literal>syntax</literal>
7474 may be specified for the <literal>backend</literal> element. The
7475 semantics of these attributes is equivalent to those for the
7476 <literal>retrieval</literal>. However, these values are passed to
7480 The <literal>backend</literal> element may include one or more
7481 conversion instructions (as children elements). The supported
7484 <varlistentry><term><literal>marc</literal></term>
7487 The <literal>marc</literal> element specifies a conversion
7488 to - and from ISO2709 encoded MARC and
7489 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7490 The following attributes may be specified:
7493 <term><literal>inputformat</literal> (REQUIRED)</term>
7496 Format of input. Supported values are
7497 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7498 (MARCXML/MarcXchange) and <literal>json</literal>
7499 (<ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>).
7504 <term><literal>outputformat</literal> (REQUIRED)</term>
7507 Format of output. Supported values are
7508 <literal>line</literal> (MARC line format);
7509 <literal>marcxml</literal> (for MARCXML),
7510 <literal>marc</literal> (ISO2709),
7511 <literal>marcxhcange</literal> (for MarcXchange),
7512 or <literal>json</literal>
7513 (<ulink url="&url.marc_in_json;">MARC-in-JSON </ulink>).
7518 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7521 Encoding of input. For XML input formats, this need not
7522 be given, but for ISO2709 based inputformats, this should
7523 be set to the encoding used. For MARC21 records, a common
7524 inputcharset value would be <literal>marc-8</literal>.
7529 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7532 Encoding of output. If outputformat is XML based, it is
7533 strongly recommened to use <literal>utf-8</literal>.
7542 <term><literal>select</literal></term>
7545 The <literal>select</literal> selects one or more text nodes
7546 and decodes them as XML.
7547 The following attributes may be specified:
7549 <varlistentry><term><literal>path</literal> (REQUIRED)</term>
7552 X-Path expression for selecting text nodes.
7559 This conversion is available in YAZ 5.8.0 and later.
7564 <term><literal>solrmarc</literal></term>
7567 The <literal>solrmarc</literal> decodes solrmarc records.
7568 It assumes that the input is pure solrmarc text (no escaping)
7569 and will convert all sequences of the form #XX; to a single
7570 character of the hexadecimal value as given by XX. The output,
7571 presumably, is a valid ISO2709 buffer.
7574 This conversion is available in YAZ 5.0.21 and later.
7579 <term><literal>xslt</literal></term>
7582 The <literal>xslt</literal> element specifies a conversion
7583 via &acro.xslt;. The following attributes may be specified:
7585 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7599 <sect2 id="tools.retrieval.examples">
7600 <title>Retrieval Facility Examples</title>
7601 <example id="tools.retrieval.marc21">
7602 <title>MARC21 backend</title>
7604 A typical way to use the retrieval facility is to enable XML
7605 for servers that only supports ISO2709 encoded MARC21 records.
7607 <programlisting><![CDATA[
7609 <retrieval syntax="usmarc" name="F"/>
7610 <retrieval syntax="usmarc" name="B"/>
7611 <retrieval syntax="xml" name="marcxml"
7612 identifier="info:srw/schema/1/marcxml-v1.1">
7613 <backend syntax="usmarc" name="F">
7614 <marc inputformat="marc" outputformat="marcxml"
7615 inputcharset="marc-8"/>
7618 <retrieval syntax="xml" name="dc">
7619 <backend syntax="usmarc" name="F">
7620 <marc inputformat="marc" outputformat="marcxml"
7621 inputcharset="marc-8"/>
7622 <xslt stylesheet="MARC21slim2DC.xsl"/>
7629 This means that our frontend supports:
7633 MARC21 F(ull) records.
7638 MARC21 B(rief) records.
7648 Dublin core records.
7654 <example id="tools.retrieval.marcxml">
7655 <title>MARCXML backend</title>
7657 SRW/SRU and Solr backends return records in XML.
7658 If they return MARCXML or MarcXchange, the retrieval module
7659 can convert those into ISO2709 formats, most commonly USMARC
7661 In this example, the backend returns MARCXML for schema="marcxml".
7663 <programlisting><![CDATA[
7665 <retrieval syntax="usmarc">
7666 <backend syntax="xml" name="marcxml">
7667 <marc inputformat="xml" outputformat="marc"
7668 outputcharset="marc-8"/>
7671 <retrieval syntax="xml" name="marcxml"
7672 identifier="info:srw/schema/1/marcxml-v1.1"/>
7673 <retrieval syntax="xml" name="dc">
7674 <backend syntax="xml" name="marcxml">
7675 <xslt stylesheet="MARC21slim2DC.xsl"/>
7682 This means that our frontend supports:
7686 MARC21 records (any element set name) in MARC-8 encoding.
7691 MARCXML records for element-set=marcxml
7696 Dublin core records for element-set=dc.
7703 <sect2 id="tools.retrieval.api">
7706 It should be easy to use the retrieval systems from applications. Refer
7708 <filename>yaz/retrieval.h</filename> and
7709 <filename>yaz/record_conv.h</filename>.
7713 <sect1 id="sorting">
7714 <title>Sorting</title>
7716 This chapter describes sorting and how it is supported in YAZ.
7717 Sorting applies to a result-set.
7719 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7720 Z39.50 sorting facility
7722 takes one or more input result-sets
7723 and one result-set as output. The most simple case is that
7724 the input-set is the same as the output-set.
7727 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7728 following a search (two phases).
7731 In SRU/Solr, however, the model is different. Here, sorting is specified
7732 during the search operation. Note, however, that SRU might
7733 perform sort as separate search, by referring to an existing result-set
7734 in the query (result-set reference).
7737 <title>Using the Z39.50 sort service</title>
7739 yaz-client and the ZOOM API support the Z39.50 sort facility. In any
7740 case the sort sequence or sort critiera is using a string notation.
7741 This notation is a one-line notation suitable for being manually
7742 entered or generated, and allows for easy logging (one liner).
7743 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7744 function. For yaz-client the sort is performed and specified using
7745 the sort and sort+ commands. For description of the sort criteria notation
7746 refer to the <link linkend="sortspec">sort command</link> in the
7750 The ZOOM API might choose one of several sort strategies for
7751 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7755 <title>Type-7 sort</title>
7757 Type-7 sort is an extension to the Bib-1 based RPN query where the
7758 sort specification is embedded as an Attribute-Plus-Term.
7761 The objectives for introducing Type-7 sorting is that it allows
7762 a client to perform sorting even if it does not implement/support
7763 Z39.50 sort. Virtually all Z39.50 client software supports
7764 RPN queries. It also may improve performance because the sort
7765 critieria is specified along with the search query.
7768 The sort is triggered by the presence of type 7, and the value of type 7
7770 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7773 The value for type 7 is 1 for ascending and 2 for descending.
7775 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7778 only the generic part is handled. If generic sortKey is of type
7779 sortField, then attribute type 1 is present and the value is
7780 sortField (InternationalString). If generic sortKey is of type
7781 sortAttributes, then the attributes in the list are used. Generic sortKey
7782 of type elementSpec is not supported.
7785 The term in the sorting Attribute-Plus-Term combo should hold
7786 an integer. The value is 0 for primary sorting criteria, 1 for second
7792 <title>Facets</title>
7794 YAZ supports facets in the Solr, SRU 2.0 and Z39.50 protocols.
7797 Like Type-1/RPN, YAZ supports a string notation for specifying
7798 facets. For the API this is performed by
7799 <function>yaz_pqf_parse_facet_list</function>.
7802 For ZOOM C the facets are given by option "facets".
7803 For yaz-client it is used for the 'facets' command.
7806 The grammar of this specification is as follows:
7808 facet-spec ::= facet-list
7810 facet-list ::= facet-list ',' attr-spec | attr-spec
7812 attr-spec ::= attr-spec '@attr' string | '@attr' string
7815 The notation is inspired by PQF. The string following '@attr'
7816 must not include blanks and is of the form
7817 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7818 where <replaceable>type</replaceable> is an integer and
7819 <replaceable>value</replaceable> is a string or an integer.
7822 The Facets specification is not Bib-1. The following types apply:
7824 <table id="facet.attributes">
7825 <title>Facet attributes</title>
7827 <colspec colwidth="2*" colname="type"></colspec>
7828 <colspec colwidth="9*" colname="description"></colspec>
7832 <entry>Description</entry>
7839 Field-name. This is often a string, e.g. "Author", "Year", etc.
7845 Sort order. Value should be an integer.
7846 Value 0: count descending (frequency). Value 1: alpha ascending.
7852 Number of terms requested.
7867 <title>The ODR Module</title>
7868 <sect1 id="odr.introduction">
7869 <title>Introduction</title>
7871 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care has been taken
7872 to isolate &odr; from the rest of the package - specifically from the
7873 transport interface. &odr; may be used in any context where basic
7874 ASN.1/BER representations are used.
7877 If you are only interested in writing a Z39.50 implementation based on
7878 the PDUs that are already provided with &yaz;, you only need to concern
7879 yourself with the section on managing ODR streams
7880 (<xref linkend="odr.use"/>). Only if you need to
7881 implement ASN.1 beyond that which has been provided, should you
7882 worry about the second half of the documentation
7883 (<xref linkend="odr.programming"/>).
7884 If you use one of the higher-level interfaces, you can skip this
7888 This is important, so we'll repeat it for emphasis: <emphasis>You do
7889 not need to read <xref linkend="odr.programming"/>
7890 to implement Z39.50 with &yaz;.</emphasis>
7893 If you need a part of the protocol that isn't already in &yaz;, you
7894 should contact the authors before going to work on it yourself: We
7895 might already be working on it. Conversely, if you implement a useful
7896 part of the protocol before us, we'd be happy to include it in a
7900 <sect1 id="odr.use">
7901 <title>Using ODR</title>
7902 <sect2 id="odr.streams">
7903 <title>ODR Streams</title>
7905 Conceptually, the ODR stream is the source of encoded data in the
7906 decoding mode; when encoding, it is the receptacle for the encoded
7907 data. Before you can use an ODR stream it must be allocated. This is
7908 done with the function
7911 ODR odr_createmem(int direction);
7914 The <function>odr_createmem()</function> function takes as argument one
7915 of three manifest constants: <literal>ODR_ENCODE</literal>,
7916 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7917 An &odr; stream can be in only one mode - it is not possible to change
7918 its mode once it's selected. Typically, your program will allocate
7919 at least two ODR streams - one for decoding, and one for encoding.
7922 When you're done with the stream, you can use
7925 void odr_destroy(ODR o);
7928 to release the resources allocated for the stream.
7931 <sect2 id="odr.memory.management">
7932 <title id="memory">Memory Management</title>
7934 Two forms of memory management take place in the &odr; system. The first
7935 one, which has to do with allocating little bits of memory (sometimes
7936 quite large bits of memory, actually) when a protocol package is
7937 decoded, and turned into a complex of interlinked structures. This
7938 section deals with this system, and how you can use it for your own
7939 purposes. The next section deals with the memory management which is
7940 required when encoding data - to make sure that a large enough buffer is
7941 available to hold the fully encoded PDU.
7944 The &odr; module has its own memory management system, which is
7945 used whenever memory is required. Specifically, it is used to allocate
7946 space for data when decoding incoming PDUs. You can use the memory
7947 system for your own purposes, by using the function
7950 void *odr_malloc(ODR o, size_t size);
7953 You can't use the normal <function>free(2)</function> routine to free
7954 memory allocated by this function, and &odr; doesn't provide a parallel
7955 function. Instead, you can call
7958 void odr_reset(ODR o);
7961 when you are done with the
7962 memory: Everything allocated since the last call to
7963 <function>odr_reset()</function> is released.
7964 The <function>odr_reset()</function> call is also required to clear
7965 up an error condition on a stream.
7971 size_t odr_total(ODR o);
7974 returns the number of bytes allocated on the stream since the last call to
7975 <function>odr_reset()</function>.
7978 The memory subsystem of &odr; is fairly efficient at allocating and
7979 releasing little bits of memory. Rather than managing the individual,
7980 small bits of space, the system maintains a free-list of larger chunks
7981 of memory, which are handed out in small bits. This scheme is
7982 generally known as a <emphasis>nibble-memory</emphasis> system.
7983 It is very useful for maintaining short-lived constructions such
7987 If you want to retain a bit of memory beyond the next call to
7988 <function>odr_reset()</function>, you can use the function
7991 ODR_MEM odr_extract_mem(ODR o);
7994 This function will give you control of the memory recently allocated
7995 on the ODR stream. The memory will live (past calls to
7996 <function>odr_reset()</function>), until you call the function
7999 void odr_release_mem(ODR_MEM p);
8002 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
8003 referencing the memory block for you until you want to release it.
8006 You can use <function>odr_extract_mem()</function> repeatedly between
8007 allocating data, to retain individual control of separate chunks of data.
8010 <sect2 id="odr.encoding.and.decoding">
8011 <title>Encoding and Decoding Data</title>
8013 When encoding data, the ODR stream will write the encoded octet string
8014 in an internal buffer. To retrieve the data, use the function
8017 char *odr_getbuf(ODR o, int *len, int *size);
8020 The integer pointed to by len is set to the length of the encoded
8021 data, and a pointer to that data is returned. <literal>*size</literal>
8022 is set to the size of the buffer (unless <literal>size</literal> is null,
8023 signaling that you are not interested in the size). The next call to
8024 a primitive function using the same &odr; stream will overwrite the
8025 data, unless a different buffer has been supplied using the call
8028 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8031 which sets the encoding (or decoding) buffer used by
8032 <literal>o</literal> to <literal>buf</literal>, using the length
8033 <literal>len</literal>.
8034 Before a call to an encoding function, you can use
8035 <function>odr_setbuf()</function> to provide the stream with an encoding
8036 buffer of sufficient size (length). The <literal>can_grow</literal>
8037 parameter tells the encoding &odr; stream whether it is allowed to use
8038 <function>realloc(2)</function> to increase the size of the buffer when
8039 necessary. The default condition of a new encoding stream is equivalent
8040 to the results of calling
8043 odr_setbuf(stream, 0, 0, 1);
8046 In this case, the stream will allocate and reallocate memory as
8047 necessary. The stream reallocates memory by repeatedly doubling the
8048 size of the buffer - the result is that the buffer will typically
8049 reach its maximum, working size with only a small number of reallocation
8050 operations. The memory is freed by the stream when the latter is destroyed,
8051 unless it was assigned by the user with the <literal>can_grow</literal>
8052 parameter set to zero (in this case, you are expected to retain
8053 control of the memory yourself).
8056 To assume full control of an encoded buffer, you must first call
8057 <function>odr_getbuf()</function> to fetch the buffer and its length.
8058 Next, you should call <function>odr_setbuf()</function> to provide a
8059 different buffer (or a null pointer) to the stream. In the simplest
8060 case, you will reuse the same buffer over and over again, and you
8061 will just need to call <function>odr_getbuf()</function> after each
8062 encoding operation to get the length and address of the buffer.
8063 Note that the stream may reallocate the buffer during an encoding
8064 operation, so it is necessary to retrieve the correct address after
8065 each encoding operation.
8068 It is important to realize that the ODR stream will not release this
8069 memory when you call <function>odr_reset()</function>: It will
8070 merely update its internal pointers to prepare for the encoding of a
8072 When the stream is released by the <function>odr_destroy()</function>
8073 function, the memory given to it by <function>odr_setbuf</function> will
8074 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
8075 parameter to <function>odr_setbuf()</function> was nonzero. The
8076 <literal>can_grow</literal> parameter, in other words, is a way of
8077 signaling who is to own the buffer, you or the ODR stream. If you never call
8078 <function>odr_setbuf()</function> on your encoding stream, which is
8079 typically the case, the buffer allocated by the stream will belong to
8080 the stream by default.
8083 When you wish to decode data, you should first call
8084 <function>odr_setbuf()</function>, to tell the decoding stream
8085 where to find the encoded data, and how long the buffer is
8086 (the <literal>can_grow</literal> parameter is ignored by a decoding
8087 stream). After this, you can call the function corresponding to the
8088 data you wish to decode (eg, <function>odr_integer()</function> odr
8089 <function>z_APDU()</function>).
8091 <example id="example.odr.encoding.and.decoding.functions">
8092 <title>Encoding and decoding functions</title>
8094 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8096 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
8100 If the data is absent (or doesn't match the tag corresponding to
8101 the type), the return value will be either 0 or 1 depending on the
8102 <literal>optional</literal> flag. If <literal>optional</literal>
8103 is 0 and the data is absent, an error flag will be raised in the
8104 stream, and you'll need to call <function>odr_reset()</function> before
8105 you can use the stream again. If <literal>optional</literal> is
8106 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
8107 <literal>p</literal> will be set to the null value, and the function
8109 The <literal>name</literal> argument is used to pretty-print the
8110 tag in question. It may be set to <literal>NULL</literal> if
8111 pretty-printing is not desired.
8114 If the data value is found where it's expected, the pointer
8115 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
8116 will be set to point to the decoded type.
8117 The space for the type will be allocated and owned by the &odr;
8118 stream, and it will live until you call
8119 <function>odr_reset()</function> on the stream. You cannot use
8120 <function>free(2)</function> to release the memory.
8121 You can decode several data elements (by repeated calls to
8122 <function>odr_setbuf()</function> and your decoding function), and
8123 new memory will be allocated each time. When you do call
8124 <function>odr_reset()</function>, everything decoded since the
8125 last call to <function>odr_reset()</function> will be released.
8127 <example id="example.odr.encoding.of.integer">
8128 <title>Encoding and decoding of an integer</title>
8130 The use of the double indirection can be a little confusing at first
8131 (its purpose will become clear later on, hopefully),
8132 so an example is in order. We'll encode an integer value, and
8133 immediately decode it again using a different stream. A useless, but
8134 informative operation.
8136 <programlisting><![CDATA[
8137 void do_nothing_useful(Odr_int value)
8140 Odr_int *valp, *resvalp;
8144 /* allocate streams */
8145 if (!(encode = odr_createmem(ODR_ENCODE)))
8147 if (!(decode = odr_createmem(ODR_DECODE)))
8151 if (odr_integer(encode, &valp, 0, 0) == 0)
8153 printf("encoding went bad\n");
8156 bufferp = odr_getbuf(encode, &len, 0);
8157 printf("length of encoded data is %d\n", len);
8159 /* now let's decode the thing again */
8160 odr_setbuf(decode, bufferp, len, 0);
8161 if (odr_integer(decode, &resvalp, 0, 0) == 0)
8163 printf("decoding went bad\n");
8166 /* ODR_INT_PRINTF format for printf (such as %d) */
8167 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
8170 odr_destroy(encode);
8171 odr_destroy(decode);
8176 This looks like a lot of work, offhand. In practice, the &odr; streams
8177 will typically be allocated once, in the beginning of your program
8178 (or at the beginning of a new network session), and the encoding
8179 and decoding will only take place in a few, isolated places in your
8180 program, so the overhead is quite manageable.
8184 <sect2 id="odr.printing">
8185 <title>Printing</title>
8187 When an ODR stream is created of type <literal>ODR_PRINT</literal>
8188 the ODR module will print the contents of a PDU in a readable format.
8189 By default output is written to the <literal>stderr</literal> stream.
8190 This behavior can be changed, however, by calling the function
8192 odr_setprint(ODR o, FILE *file);
8194 before encoders or decoders are being invoked.
8195 It is also possible to direct the output to a buffer (or indeed
8196 another file), by using the more generic mechanism:
8198 void odr_set_stream(ODR o, void *handle,
8199 void (*stream_write)(ODR o, void *handle, int type,
8200 const char *buf, int len),
8201 void (*stream_close)(void *handle));
8203 Here the user provides an opaque handle and two handlers,
8204 <replaceable>stream_write</replaceable> for writing,
8205 and <replaceable>stream_close</replaceable> which is supposed
8206 to close/free resources associated with handle.
8207 The <replaceable>stream_close</replaceable> handler is optional and
8208 if NULL for the function is provided, it will not be invoked.
8209 The <replaceable>stream_write</replaceable> takes the ODR handle
8210 as parameter, the user-defined handle, a type
8211 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8212 which indicates the type of contents being written.
8215 Another utility useful for diagnostics (error handling) or as
8216 part of the printing facilities is:
8218 const char **odr_get_element_path(ODR o);
8220 which returns a list of current elements that ODR deals with at the
8221 moment. For the returned array, say <literal>ar</literal>,
8222 then <literal>ar[0]</literal> is the top level element,
8223 <literal>ar[n]</literal> is the last. The last element has the
8224 property that <literal>ar[n+1] == NULL</literal>.
8226 <example id="example.odr.element.path.record">
8227 <title>Element Path for record</title>
8229 For a database record part of a PresentResponse the
8230 array returned by <function>odr_get_element</function>
8231 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8232 unnamed constructions.
8236 <sect2 id="odr.diagnostics">
8237 <title>Diagnostics</title>
8239 The encoding/decoding functions all return 0 when an error occurs.
8240 Until you call <function>odr_reset()</function>, you cannot use the
8241 stream again, and any function called will immediately return 0.
8244 To provide information to the programmer or administrator, the function
8247 void odr_perror(ODR o, char *message);
8250 is provided, which prints the <literal>message</literal> argument to
8251 <literal>stderr</literal> along with an error message from the stream.
8254 You can also use the function
8257 int odr_geterror(ODR o);
8260 to get the current error number from the screen. The number will be
8261 one of these constants:
8263 <table frame="top" id="odr.error.codes">
8264 <title>ODR Error codes</title>
8269 <entry>Description</entry>
8274 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8277 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8278 The standard diagnostic variable <literal>errno</literal> should be
8279 examined to determine the actual error.</entry>
8282 <entry>OSPACE</entry><entry>No more space for encoding.
8283 This will only occur when the user has explicitly provided a
8284 buffer for an encoding stream without allowing the system to
8285 allocate more space.</entry>
8288 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8289 required data element was missing during encoding or decoding.</entry>
8292 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8293 found during decoding.</entry>
8296 <entry>OOTHER</entry><entry>Other error. This is typically an
8297 indication of misuse of the &odr; system by the programmer, and also
8298 that the diagnostic system isn't as good as it should be, yet.</entry>
8304 The character string array
8310 can be indexed by the error code to obtain a human-readable
8311 representation of the problem.
8314 <sect2 id="odr.summary.and.synopsis">
8315 <title>Summary and Synopsis</title>
8317 #include <yaz/odr.h>
8319 ODR odr_createmem(int direction);
8321 void odr_destroy(ODR o);
8323 void odr_reset(ODR o);
8325 char *odr_getbuf(ODR o, int *len, int *size);
8327 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8329 void *odr_malloc(ODR o, int size);
8331 NMEM odr_extract_mem(ODR o);
8333 int odr_geterror(ODR o);
8335 void odr_perror(ODR o, const char *message);
8337 extern char *odr_errlist[];
8341 <sect1 id="odr.programming">
8342 <title>Programming with ODR</title>
8344 The API of &odr; is designed to reflect the structure of ASN.1, rather
8345 than BER itself. Future releases may be able to represent data in
8346 other external forms.
8350 There is an ASN.1 tutorial available at
8351 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8352 This site also has standards for ASN.1 (X.680) and BER (X.690)
8353 <ulink url="&url.asn.1.standards;">online</ulink>.
8357 The ODR interface is based loosely on that of the Sun Microsystems
8359 Specifically, each function which corresponds to an ASN.1 primitive
8360 type has a dual function. Depending on the settings of the ODR
8361 stream which is supplied as a parameter, the function may be used
8362 either to encode or decode data. The functions that can be built
8363 using these primitive functions, to represent more complex data types,
8364 share this quality. The result is that you only have to enter the
8365 definition for a type once - and you have the functionality of encoding,
8366 decoding (and pretty-printing) all in one unit.
8367 The resulting C source code is quite compact, and is a pretty
8368 straightforward representation of the source ASN.1 specification.
8371 In many cases, the model of the XDR functions works quite well in this
8373 In others, it is less elegant. Most of the hassle comes from the optional
8374 SEQUENCE members which don't exist in XDR.
8376 <sect2 id="odr.primitive.asn1.types">
8377 <title>The Primitive ASN.1 Types</title>
8379 ASN.1 defines a number of primitive types (many of which correspond
8380 roughly to primitive types in structured programming languages, such as C).
8382 <sect3 id="odr.integer">
8383 <title>INTEGER</title>
8385 The &odr; function for encoding or decoding (or printing) the ASN.1
8386 INTEGER type looks like this:
8389 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8392 The <literal>Odr_int</literal> is just a simple integer.
8395 This form is typical of the primitive &odr; functions. They are named
8396 after the type of data that they encode or decode. They take an &odr;
8397 stream, an indirect reference to the type in question, and an
8398 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8399 of ASN.1) as parameters. They all return an integer value of either one
8401 When you use the primitive functions to construct encoders for complex
8402 types of your own, you should follow this model as well. This
8403 ensures that your new types can be reused as elements in yet more
8407 The <literal>o</literal> parameter should obviously refer to a properly
8408 initialized &odr; stream of the right type (encoding/decoding/printing)
8409 for the operation that you wish to perform.
8412 When encoding or printing, the function first looks at
8413 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8414 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8415 the data element is absent. If the <literal>optional</literal> parameter
8416 is nonzero, the function will return one (signifying success) without
8417 any further processing. If the <literal>optional</literal> is zero, an
8418 internal error flag is set in the &odr; stream, and the function will
8419 return 0. No further operations can be carried out on the stream without
8420 a call to the function <function>odr_reset()</function>.
8423 If <literal>*p</literal> is not a null pointer, it is expected to
8424 point to an instance of the data type. The data will be subjected to
8425 the encoding rules, and the result will be placed in the buffer held
8426 by the &odr; stream.
8429 The other ASN.1 primitives have similar functions that operate in
8433 <sect3 id="odr.boolean">
8434 <title>BOOLEAN</title>
8436 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8439 <sect3 id="odr.real">
8445 <sect3 id="odr.null">
8448 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8451 In this case, the value of **p is not important. If <literal>*p</literal>
8452 is different from the null pointer, the null value is present, otherwise
8456 <sect3 id="odr.octet.string">
8457 <title>OCTET STRING</title>
8459 typedef struct odr_oct
8465 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8469 The <literal>buf</literal> field should point to the character array
8470 that holds the octetstring. The <literal>len</literal> field holds the
8472 The character array need not be null-terminated.
8475 To make things a little easier, an alternative is given for string
8476 types that are not expected to contain embedded NULL characters (e.g.
8480 int odr_cstring(ODR o, char **p, int optional, const char *name);
8483 which encodes or decodes between OCTETSTRING representations and
8484 null-terminated C strings.
8487 Functions are provided for the derived string types, e.g.:
8490 int odr_visiblestring(ODR o, char **p, int optional,
8494 <sect3 id="odr.bit.string">
8495 <title>BIT STRING</title>
8497 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8501 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8502 holding relatively brief bit strings, e.g. for options fields, etc.
8503 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8504 gives the maximum possible number of bits.
8507 A set of macros are provided for manipulating the
8508 <literal>Odr_bitmask</literal> type:
8511 void ODR_MASK_ZERO(Odr_bitmask *b);
8513 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8515 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8517 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8520 The functions are modeled after the manipulation functions that
8521 accompany the <literal>fd_set</literal> type used by the
8522 <function>select(2)</function> call.
8523 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8524 new bitmask, to initialize the bits to zero.
8527 <sect3 id="odr.object.identifier">
8528 <title>OBJECT IDENTIFIER</title>
8530 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8533 The C OID representation is simply an array of integers, terminated by
8534 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8535 the <literal>short</literal> type).
8536 We suggest that you use the OID database module (see
8537 <xref linkend="tools.oid.database"/>) to handle object identifiers
8538 in your application.
8542 <sect2 id="odr.tagging.primitive.types">
8543 <title>Tagging Primitive Types</title>
8545 The simplest way of tagging a type is to use the
8546 <function>odr_implicit_tag()</function> or
8547 <function>odr_explicit_tag()</function> macros:
8550 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8551 int optional, const char *name);
8553 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8554 int optional, const char *name);
8557 To create a type derived from the integer type by implicit tagging, you
8561 MyInt ::= [210] IMPLICIT INTEGER
8564 In the &odr; system, this would be written like:
8567 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8569 return odr_implicit_tag(o, odr_integer, p,
8570 ODR_CONTEXT, 210, optional, name);
8574 The function <function>myInt()</function> can then be used like any of
8575 the primitive functions provided by &odr;. Note that the behavior of
8576 <function>odr_explicit_tag()</function>
8577 and <function>odr_implicit_tag()</function> macros
8578 act exactly the same as the functions they are applied to - they
8579 respond to error conditions, etc, in the same manner - they
8580 simply have three extra parameters. The class parameter may
8581 take one of the values: <literal>ODR_CONTEXT</literal>,
8582 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8583 <literal>/ODR_APPLICATION</literal>.
8586 <sect2 id="odr.constructed.types">
8587 <title>Constructed Types</title>
8589 Constructed types are created by combining primitive types. The
8590 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8591 (although adding the rest of the container types should be simple
8592 enough, if the need arises).
8595 For implementing SEQUENCEs, the functions
8598 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8599 int odr_sequence_end(ODR o);
8605 The <function>odr_sequence_begin()</function> function should be
8606 called in the beginning of a function that implements a SEQUENCE type.
8607 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8608 you're implementing), and the <literal>size</literal> of the type
8609 (typically a C structure). On encoding, it returns 1 if
8610 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8611 parameter is ignored. On decoding, it returns 1 if the type is found in
8612 the data stream. <literal>size</literal> bytes of memory are allocated,
8613 and <literal>*p</literal> is set to point to this space.
8614 The <function>odr_sequence_end()</function> is called at the end of the
8615 complex function. Assume that a type is defined like this:
8618 MySequence ::= SEQUENCE {
8620 boolval BOOLEAN OPTIONAL
8624 The corresponding &odr; encoder/decoder function and the associated data
8625 structures could be written like this:
8628 typedef struct MySequence
8634 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8636 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8637 return optional && odr_ok(o);
8639 odr_integer(o, &(*p)->intval, 0, "intval") &&
8640 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8641 odr_sequence_end(o);
8645 Note the 1 in the call to <function>odr_bool()</function>, to mark
8646 that the sequence member is optional.
8647 If either of the member types had been tagged, the macros
8648 <function>odr_implicit_tag()</function> or
8649 <function>odr_explicit_tag()</function>
8650 could have been used.
8651 The new function can be used exactly like the standard functions provided
8652 with &odr;. It will encode, decode or pretty-print a data value of the
8653 <literal>MySequence</literal> type. We like to name types with an
8654 initial capital, as done in ASN.1 definitions, and to name the
8655 corresponding function with the first character of the name in lower case.
8656 You could, of course, name your structures, types, and functions any way
8657 you please - as long as you're consistent, and your code is easily readable.
8658 <literal>odr_ok</literal> is just that - a predicate that returns the
8659 state of the stream. It is used to ensure that the behavior of the new
8660 type is compatible with the interface of the primitive types.
8663 <sect2 id="odr.tagging.constructed.types">
8664 <title>Tagging Constructed Types</title>
8667 See <xref linkend="odr.tagging.primitive.types"/> for information
8668 on how to tag the primitive types, as well as types that are
8672 <sect3 id="odr.implicit.tagging">
8673 <title>Implicit Tagging</title>
8675 Assume the type above had been defined as
8678 MySequence ::= [10] IMPLICIT SEQUENCE {
8680 boolval BOOLEAN OPTIONAL
8684 You would implement this in &odr; by calling the function
8687 int odr_implicit_settag(ODR o, int class, int tag);
8690 which overrides the tag of the type immediately following it. The
8691 macro <function>odr_implicit_tag()</function> works by calling
8692 <function>odr_implicit_settag()</function> immediately
8693 before calling the function pointer argument.
8694 Your type function could look like this:
8697 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8699 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8700 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8701 return optional && odr_ok(o);
8703 odr_integer(o, &(*p)->intval, 0, "intval") &&
8704 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8705 odr_sequence_end(o);
8709 The definition of the structure <literal>MySequence</literal> would be
8713 <sect3 id="odr.explicit.tagging">
8714 <title>Explicit Tagging</title>
8716 Explicit tagging of constructed types is a little more complicated,
8717 since you are in effect adding a level of construction to the data.
8720 Assume the definition:
8723 MySequence ::= [10] IMPLICIT SEQUENCE {
8725 boolval BOOLEAN OPTIONAL
8729 Since the new type has an extra level of construction, two new functions
8730 are needed to encapsulate the base type:
8733 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8736 int odr_constructed_end(ODR o);
8739 Assume that the IMPLICIT in the type definition above were replaced
8740 with EXPLICIT (or that the IMPLICIT keyword was simply deleted, which
8741 would be equivalent). The structure definition would look the same,
8742 but the function would look like this:
8745 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8747 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8748 return optional && odr_ok(o);
8749 if (o->direction == ODR_DECODE)
8750 *p = odr_malloc(o, sizeof(**p));
8751 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8753 *p = 0; /* this is almost certainly a protocol error */
8757 odr_integer(o, &(*p)->intval, 0, "intval") &&
8758 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8759 odr_sequence_end(o) &&
8760 odr_constructed_end(o);
8764 Notice that the interface here gets kind of nasty. The reason is
8765 simple: Explicitly tagged, constructed types are fairly rare in
8766 the protocols that we care about, so the
8767 aesthetic annoyance (not to mention the dangers of a cluttered
8768 interface) is less than the time that would be required to develop a
8769 better interface. Nevertheless, it is far from satisfying, and it's a
8770 point that will be worked on in the future. One option for you would
8771 be to simply apply the <function>odr_explicit_tag()</function> macro to
8772 the first function, and not
8773 have to worry about <function>odr_constructed_*</function> yourself.
8774 Incidentally, as you might have guessed, the
8775 <function>odr_sequence_</function> functions are themselves
8776 implemented using the <function>/odr_constructed_</function> functions.
8780 <sect2 id="odr.sequence.of">
8781 <title>SEQUENCE OF</title>
8783 To handle sequences (arrays) of a specific type, the function
8786 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8787 void *p, int *num, const char *name);
8790 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8791 function of the type. <literal>p</literal> is a pointer to an array of
8792 pointers to your type. <literal>num</literal> is the number of elements
8799 MyArray ::= SEQUENCE OF INTEGER
8802 The C representation might be
8805 typedef struct MyArray
8812 And the function might look like
8815 int myArray(ODR o, MyArray **p, int optional, const char *name)
8817 if (o->direction == ODR_DECODE)
8818 *p = odr_malloc(o, sizeof(**p));
8819 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8820 &(*p)->num_elements, name))
8823 return optional && odr_ok(o);
8827 <sect2 id="odr.choice.types">
8828 <title>CHOICE Types</title>
8830 The choice type is used fairly often in some ASN.1 definitions, so
8831 some work has gone into streamlining its interface.
8834 CHOICE types are handled by the function:
8837 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8841 The <literal>arm</literal> array is used to describe each of the possible
8842 types that the CHOICE type may assume. Internally in your application,
8843 the CHOICE type is represented as a discriminated union. That is, a
8844 C union accompanied by an integer (or enum) identifying the active
8846 <literal>whichp</literal> is a pointer to the union discriminator.
8847 When encoding, it is examined to determine the current type.
8848 When decoding, it is set to reference the type that was found in
8852 The Odr_arm type is defined thus:
8855 typedef struct odr_arm
8866 The interpretation of the fields are:
8870 <term>tagmode</term>
8871 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8872 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8873 to mark no tagging.</para></listitem>
8877 <listitem><para>The value of the discriminator that corresponds to
8878 this CHOICE element. Typically, it will be a #defined constant, or
8879 an enum member.</para></listitem>
8883 <listitem><para>A pointer to a function that implements the type of
8884 the CHOICE member. It may be either a standard &odr; type or a type
8885 defined by yourself.</para></listitem>
8889 <listitem><para>Name of tag.</para></listitem>
8893 A handy way to prepare the array for use by the
8894 <function>odr_choice()</function> function is to
8895 define it as a static, initialized array in the beginning of your
8896 decoding/encoding function. Assume the type definition:
8899 MyChoice ::= CHOICE {
8901 tagged [99] IMPLICIT INTEGER,
8906 Your C type might look like
8909 typedef struct MyChoice
8926 And your function could look like this:
8929 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8931 static Odr_arm arm[] =
8933 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8934 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8936 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8940 if (o->direction == ODR_DECODE)
8941 *p = odr_malloc(o, sizeof(**p);
8943 return optional && odr_ok(o);
8945 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8948 return optional && odr_ok(o);
8952 In some cases (say, a non-optional choice which is a member of a
8953 sequence), you can "embed" the union and its discriminator in the
8954 structure belonging to the enclosing type, and you won't need to
8955 fiddle with memory allocation to create a separate structure to
8956 wrap the discriminator and union.
8959 The corresponding function is somewhat nicer in the Sun XDR interface.
8960 Most of the complexity of this interface comes from the possibility of
8961 declaring sequence elements (including CHOICEs) optional.
8964 The ASN.1 specifications naturally require that each member of a
8965 CHOICE have a distinct tag, so they can be told apart on decoding.
8966 Sometimes it can be useful to define a CHOICE that has multiple types
8967 that share the same tag. You'll need some other mechanism, perhaps
8968 keyed to the context of the CHOICE type. In effect, we would like to
8969 introduce a level of context-sensitiveness to our ASN.1 specification.
8970 When encoding an internal representation, we have no problem, as long
8971 as each CHOICE member has a distinct discriminator value. For
8972 decoding, we need a way to tell the choice function to look for a
8973 specific arm of the table. The function
8976 void odr_choice_bias(ODR o, int what);
8979 provides this functionality. When called, it leaves a notice for the next
8980 call to <function>odr_choice()</function> to be called on the decoding
8981 stream <literal>o</literal>, that only the <literal>arm</literal> entry with
8982 a <literal>which</literal> field equal to <literal>what</literal>
8986 The most important application (perhaps the only one, really) is in
8987 the definition of application-specific EXTERNAL encoders/decoders
8988 which will automatically decode an ANY member given the direct or
8993 <sect1 id="odr.debugging">
8994 <title>Debugging</title>
8996 The protocol modules are suffering somewhat from a lack of diagnostic
8997 tools at the moment. Specifically ways to pretty-print PDUs that
8998 aren't recognized by the system. We'll include something to this end
8999 in a not-too-distant release. In the meantime, what we do when we get
9000 packages we don't understand is to compile the ODR module with
9001 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
9002 information as it processes data units. With this output and the
9003 protocol specification (Z39.50), it is generally fairly easy to see
9008 <chapter id="comstack">
9009 <title>The COMSTACK Module</title>
9010 <sect1 id="comstack.synopsis">
9011 <title>Synopsis (blocking mode)</title>
9012 <programlisting><![CDATA[
9015 int size = 0, length_incoming;
9016 char server_address_str[] = "localhost:9999";
9017 void *server_address_ip;
9020 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
9021 int protocol_package_length = strlen(protocol_package);
9023 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
9025 perror("cs_create"); /* use perror() here since we have no stack yet */
9029 server_address_ip = cs_straddr(stack, server_address_str);
9030 if (!server_address_ip) {
9031 fprintf(stderr, "cs_straddr: address could not be resolved\n");
9035 status = cs_connect(stack, server_address_ip);
9037 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
9041 status = cs_rcvconnect(stack);
9043 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
9047 status = cs_put(stack, protocol_package, protocol_package_length);
9049 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
9053 /* Now get a response */
9054 length_incoming = cs_get(stack, &buf, &size);
9055 if (!length_incoming) {
9056 fprintf(stderr, "Connection closed\n");
9058 } else if (length_incoming < 0) {
9059 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
9064 fwrite(buf, length_incoming, 1, stdout);
9075 <sect1 id="comstack.introduction">
9076 <title>Introduction</title>
9079 subsystem provides a transparent interface to different types of transport
9080 stacks for the exchange of BER-encoded data and HTTP packets.
9081 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
9082 experimental SSL stack are supported, but others may be added in time.
9083 The philosophy of the
9084 module is to provide a simple interface by hiding unused options and
9085 facilities of the underlying libraries. This is always done at the risk
9086 of losing generality, and it may prove that the interface will need
9091 There hasn't been interest in the XTImOSI stack for some years.
9092 Therefore, it is no longer supported.
9096 The interface is implemented in such a fashion that only the
9097 sub-layers constructed to the transport methods that you wish to
9098 use in your application are linked in.
9101 You will note that even though simplicity was a goal in the design,
9102 the interface is still orders of magnitudes more complex than the
9103 transport systems found in many other packages. One reason is that
9104 the interface needs to support the somewhat different requirements of
9105 the different lower-layer communications stacks; another important
9106 reason is that the interface seeks to provide a more or less
9107 industrial-strength approach to asynchronous event-handling.
9108 When no function is allowed to block, things get more complex -
9109 particularly on the server side.
9110 We urge you to have a look at the demonstration client and server
9111 provided with the package. They are meant to be easily readable and
9112 instructive, while still being at least moderately useful.
9115 <sect1 id="comstack.common">
9116 <title>Common Functions</title>
9117 <sect2 id="comstack.managing.endpoints">
9118 <title>Managing Endpoints</title>
9120 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9123 Creates an instance of the protocol stack - a communications endpoint.
9124 The <literal>type</literal> parameter determines the mode
9125 of communication. At present the following values are supported:
9129 <term><literal>tcpip_type</literal></term>
9130 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
9134 <term><literal>ssl_type</literal></term>
9135 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
9136 is experimental and is not fully implemented. If
9137 HTTP is used, this effectively is HTTPS.
9141 <term><literal>unix_type</literal></term>
9142 <listitem><para>Unix socket (unix only). Local Transfer via
9143 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
9144 <manvolnum>7</manvolnum></citerefentry>.
9149 The <function>cs_create</function> function returns a null-pointer
9150 if a system error occurs.
9151 The <literal>blocking</literal> parameter should be '1' if
9152 you wish the association to operate in blocking mode, and '0' otherwise.
9153 The <literal>protocol</literal> field should be
9154 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
9155 Protocol <literal>PROTO_SR</literal> is no longer supported.
9158 void cs_close(COMSTACK handle);
9161 Closes the connection (as elegantly as the lower layers will permit),
9162 and releases the resources pointed to by the
9163 <literal>handle</literal>
9165 <literal>handle</literal>
9166 should not be referenced again after this call.
9170 We really need a soft disconnect, don't we?
9174 <sect2 id="comstack.data.exchange">
9175 <title>Data Exchange</title>
9177 int cs_put(COMSTACK handle, char *buf, int len);
9180 Sends <literal>buf</literal> down the wire.
9181 In blocking mode, this function will return only when a full buffer has
9182 been written, or an error has occurred. In nonblocking mode, it's
9183 possible that the function will be unable to send the full buffer
9184 at once, which will be indicated by a return value of 1.
9185 The function will keep track of the number of octets already written; you
9186 should call it repeatedly with the same values of <literal>buf</literal>
9187 and <literal>len</literal>, until the buffer has been transmitted.
9188 When a full buffer has been sent, the function will return 0 for
9189 success. The return value -1 indicates an error condition (see below).
9192 int cs_get(COMSTACK handle, char **buf, int *size);
9195 Receives a PDU or HTTP Response from the peer. Returns the number of
9197 In nonblocking mode, it is possible that not all of the packet can be
9198 read at once. In this case, the function returns 1. To simplify the
9199 interface, the function is
9200 responsible for managing the size of the buffer. It will be reallocated
9201 if necessary to contain large packages, and will sometimes be moved
9202 around internally by the subsystem when partial packages are read. Before
9204 <function>cs_get</function>
9205 for the first time, the buffer can be initialized to the null pointer,
9206 and the length should also be set to 0 (cs_get will perform a
9207 <function>malloc(2)</function>
9208 on the buffer for you). When a full buffer has been read, the size of
9209 the package is returned (which will always be greater than 1).
9210 The return value -1 indicates an error condition.
9213 See also the <function>cs_more()</function> function below.
9216 int cs_more(COMSTACK handle);
9219 The <function>cs_more()</function> function should be used in conjunction
9220 with <function>cs_get</function> and
9221 <function>select(2)</function>.
9222 The <function>cs_get()</function> function will sometimes
9223 (notably in the TCP/IP mode) read more than a single protocol package
9224 off the network. When this happens, the extra package is stored
9225 by the subsystem. After calling <function>cs_get()</function>, and before
9226 waiting for more input, You should always call
9227 <function>cs_more()</function>
9228 to check if there's a full protocol package already read. If
9229 <function>cs_more()</function>
9231 <function>cs_get()</function>
9232 can be used to immediately fetch the new package. For the
9234 subsystem, the function should always return 0, but if you want your
9235 stuff to be protocol independent, you should use it.
9239 The <function>cs_more()</function>
9240 function is required because the RFC1729-method
9241 does not provide a way of separating individual PDUs, short of
9242 partially decoding the BER. Some other implementations will carefully
9243 nibble at the packet by calling
9244 <function>read(2)</function>
9245 several times. This was felt to be too inefficient (or at least
9246 clumsy) - hence the call for this extra function.
9250 int cs_look(COMSTACK handle);
9253 This function is useful when you're operating in nonblocking
9255 <function>select(2)</function>
9256 tells you there's something happening on the line. It returns one of
9257 the following values:
9261 <term>CS_NONE</term>
9263 No event is pending. The data found on the line was not a
9268 <term>CS_CONNECT</term>
9270 A response to your connect request has been received. Call
9271 <function>cs_rcvconnect</function>
9272 to process the event and to finalize the connection establishment.
9276 <term>CS_DISCON</term>
9278 The other side has closed the connection (or maybe sent a disconnect
9279 request - but do we care? Maybe later). Call
9280 <function>cs_close</function> to close your end of the association
9285 <term>CS_LISTEN</term>
9287 A connect request has been received.
9288 Call <function>cs_listen</function> to process the event.
9292 <term>CS_DATA</term>
9294 There's data to be found on the line.
9295 Call <function>cs_get</function> to get it.
9301 You should be aware that even if
9302 <function>cs_look()</function>
9303 tells you that there's an event event pending, the corresponding
9304 function may still return and tell you there was nothing to be found.
9305 This means that only part of a package was available for reading. The
9306 same event will show up again, when more data has arrived.
9310 int cs_fileno(COMSTACK h);
9313 returns the file descriptor of the association. Use this when
9314 file-level operations on the endpoint are required
9315 (<function>select(2)</function> operations, specifically).
9319 <sect1 id="comstack.client">
9320 <title>Client Side</title>
9322 int cs_connect(COMSTACK handle, void *address);
9325 Initiate a connection with the target at <literal>address</literal>
9326 (more on addresses below). The function will return 0 on success, and 1 if
9327 the operation does not complete immediately (this will only
9328 happen on a nonblocking endpoint). In this case, use
9329 <function>cs_rcvconnect</function> to complete the operation,
9330 when <function>select(2)</function> or <function>poll(2)</function>
9331 reports input pending on the association.
9334 int cs_rcvconnect(COMSTACK handle);
9337 Complete a connect operation initiated by <function>cs_connect()</function>.
9338 It will return 0 on success; 1 if the operation has not yet completed (in
9339 this case, call the function again later); -1 if an error has occurred.
9342 <sect1 id="comstack.server">
9343 <title>Server Side</title>
9345 To establish a server under the <application>inetd</application>
9349 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9353 The <literal>socket</literal> parameter is an established socket (when
9354 your application is invoked from <application>inetd</application>, the
9355 socket will typically be 0.
9356 The following parameters are identical to the ones for
9357 <function>cs_create</function>.
9360 int cs_bind(COMSTACK handle, void *address, int mode)
9363 Binds a local address to the endpoint. Read about addresses below. The
9364 <literal>mode</literal> parameter should be either
9365 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9368 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9371 Call this to process incoming events on an endpoint that has been
9372 bound in listening mode. It will return 0 to indicate that the connect
9373 request has been received, 1 to signal a partial reception, and -1 to
9374 indicate an error condition.
9377 COMSTACK cs_accept(COMSTACK handle);
9380 This finalizes the server-side association establishment, after
9381 cs_listen has completed successfully. It returns a new connection
9382 endpoint, which represents the new association. The application will
9383 typically wish to fork off a process to handle the association at this
9384 point, and continue listen for new connections on the old
9385 <literal>handle</literal>.
9388 You can use the call
9391 const char *cs_addrstr(COMSTACK);
9394 on an established connection to retrieve the host-name of the remote host.
9398 You may need to use this function with some care if your
9399 name server service is slow or unreliable.
9403 <sect1 id="comstack.addresses">
9404 <title>Addresses</title>
9406 The low-level format of the addresses are different depending on the
9407 mode of communication you have chosen. A function is provided by each
9408 of the lower layers to map a user-friendly string-form address to the
9409 binary form required by the lower layers.
9412 void *cs_straddr(COMSTACK handle, const char *str);
9415 The format for TCP/IP and SSL addresses is:
9418 <host> [ ':' <portnum> ]
9421 The <literal>hostname</literal> can be either a domain name or an
9422 IP address. The port number, if omitted, defaults to 210.
9425 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9426 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9427 IPV4 binding as well (bindv6only=0),
9428 The special hostname <literal>@4</literal> binds to
9429 <literal>INADDR_ANY</literal> (IPV4 only listener).
9430 The special hostname <literal>@6</literal> binds to
9431 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9434 For UNIX sockets, the format of an address is the socket filename.
9437 When a connection has been established, you can use
9440 const char *cs_addrstr(COMSTACK h);
9443 to retrieve the host name of the peer system. The function returns
9444 a pointer to a static area, which is overwritten on the next call
9448 A fairly recent addition to the &comstack; module is the utility
9452 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9455 which is just a wrapper for <function>cs_create</function> and
9456 <function>cs_straddr</function>. The <parameter>str</parameter>
9457 is similar to that described for <function>cs_straddr</function>
9458 but with a prefix denoting the &comstack; type. Prefixes supported
9459 are <literal>tcp:</literal> and <literal>unix:</literal> and
9460 <literal>ssl:</literal> for TCP/IP and UNIX and SSL respectively.
9461 If no prefix is given, then TCP/IP is used.
9462 The <parameter>blocking</parameter> is passed to
9463 function <function>cs_create</function>. The third parameter
9464 <parameter>vp</parameter> is a pointer to &comstack; stack type
9466 Parameter <parameter>vp</parameter> is reserved for future use.
9467 Set it to <literal>NULL</literal>.
9470 <sect1 id="comstack.ssl">
9474 void *cs_get_ssl(COMSTACK cs);
9476 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9477 is not of type SSL, then NULL is returned.
9481 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9483 Sets SSL context for comstack. The parameter is expected to be of type
9484 <literal>SSL_CTX *</literal>. This function should be called just
9485 after comstack has been created (before connect, bind, etc).
9486 This function returns 1 for success; 0 for failure.
9490 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9492 Sets SSL certificate for comstack as a PEM file. This function
9493 returns 1 for success; 0 for failure.
9497 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9499 This function returns the peer certificate. If successful,
9500 <literal>*buf</literal> and <literal>*len</literal> holds
9501 X509 buffer and length respectively. Buffer should be freed
9502 with <literal>xfree</literal>. This function returns 1 for success;
9506 <sect1 id="comstack.diagnostics">
9507 <title>Diagnostics</title>
9509 All functions return -1 if an error occurs. Typically, the functions
9510 will return 0 on success, but the data exchange functions
9511 (<function>cs_get</function>, <function>cs_put</function>,
9512 <function>cs_more</function>) follow special rules. Consult their
9516 The error code for the COMSTACK can be retrieved using C macro
9517 <function>cs_errno</function> which will return one
9518 of the error codes <literal>CSYSERR</literal>,
9519 <literal>CSOUTSTATE</literal>,
9520 <literal>CSNODATA</literal>, ...
9523 int cs_errno(COMSTACK handle);
9526 You can the textual representation of the error code
9527 by using <function>cs_errmsg</function>, which
9528 works like <function>strerror(3)</function>.
9531 const char *cs_errmsg(int n);
9534 It is also possible to get straight to the textual representation
9535 without the error code, by using
9536 <function>cs_strerror</function>.
9539 const char *cs_strerror(COMSTACK h);
9542 <sect1 id="comstack.summary">
9543 <title>Summary and Synopsis</title>
9545 #include <yaz/comstack.h>
9547 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9548 #include <yaz/unix.h> /* this is for UNIX socket support */
9550 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9552 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9554 COMSTACK cs_create_host(const char *str, int blocking,
9557 int cs_bind(COMSTACK handle, int mode);
9559 int cs_connect(COMSTACK handle, void *address);
9561 int cs_rcvconnect(COMSTACK handle);
9563 int cs_listen(COMSTACK handle);
9565 COMSTACK cs_accept(COMSTACK handle);
9567 int cs_put(COMSTACK handle, char *buf, int len);
9569 int cs_get(COMSTACK handle, char **buf, int *size);
9571 int cs_more(COMSTACK handle);
9573 void cs_close(COMSTACK handle);
9575 int cs_look(COMSTACK handle);
9577 void *cs_straddr(COMSTACK handle, const char *str);
9579 const char *cs_addrstr(COMSTACK h);
9584 <chapter id="future">
9585 <title>Future Directions</title>
9587 We have a new and better version of the front-end server on the drawing
9588 board. Resources and external commitments will govern when we'll be
9589 able to do something real with it. Features should include greater
9590 flexibility, greater support for access/resource control, and easy
9591 support for Explain (possibly with Zebra as an extra database engine).
9594 &yaz; is a BER toolkit and as such should support all protocols
9595 out there based on that. We'd like to see running ILL applications.
9596 It shouldn't be that hard. Another thing that would be interesting is
9597 LDAP. Maybe a generic framework for doing IR using both LDAP and
9598 Z39.50 transparently.
9601 The SOAP implementation is incomplete. In the future we hope
9602 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9603 The authors of libxml2 are already working on XML Schema / RelaxNG
9604 compilers so this may not be too hard.
9607 It would be neat to have a proper module mechanism for the Generic
9608 Frontend Server so that backend would be dynamically
9609 loaded (as shared objects / DLLs).
9612 Other than that, &yaz; generally moves in the directions which appear to
9613 make the most people happy (including ourselves, as prime users of the
9614 software). If there's something you'd like to see in here, then drop
9615 us a note and let's see what we can come up with.
9618 <reference id="reference">
9619 <title>Reference</title>
9620 <partintro id="reference-introduction">
9622 The material in this chapter is drawn directly from the individual
9628 <appendix id="list-oids">
9629 <title>List of Object Identifiers</title>
9631 These is a list of object identifiers that are built into YAZ.
9635 <appendix id="bib1-diagnostics">
9636 <title>Bib-1 diagnostics</title>
9638 List of Bib-1 diagnostics that are known to YAZ.
9642 <appendix id="sru-diagnostics">
9643 <title>SRU diagnostics</title>
9645 List of SRU diagnostics that are known to YAZ.
9649 <appendix id="license">
9650 <title>License</title>
9651 <sect1 id="license.indexdata">
9652 <title>Index Data Copyright</title>
9654 Copyright © ©right-year; Index Data.
9657 All rights reserved.
9660 Redistribution and use in source and binary forms, with or without
9661 modification, are permitted provided that the following conditions are met:
9666 Redistributions of source code must retain the above copyright
9667 notice, this list of conditions and the following disclaimer.
9672 Redistributions in binary form must reproduce the above copyright
9673 notice, this list of conditions and the following disclaimer in the
9674 documentation and/or other materials provided with the distribution.
9679 Neither the name of Index Data nor the names of its contributors
9680 may be used to endorse or promote products derived from this
9681 software without specific prior written permission.
9686 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9687 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9688 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9689 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9690 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9691 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9692 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9693 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9694 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9695 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9700 <appendix id="indexdata">
9701 <title>About Index Data</title>
9703 Index Data is a consulting and software-development enterprise that
9704 specializes in library and information management systems. Our
9705 interests and expertise span a broad range of related fields, and one
9706 of our primary, long-term objectives is the development of a powerful
9707 information management
9708 system with open network interfaces and hyper-media capabilities.
9710 We make this software available free of charge, on a fairly unrestrictive
9711 license; as a service to the networking community, and to further the
9712 development of quality software for open network communication.
9714 We'll be happy to answer questions about the software, and about ourselves
9720 <street>Amagerfælledvej 56</street>
9721 <postcode>2300 Copenhagen S</postcode>
9722 <country>Denmark</country>
9723 Email <email>info@indexdata.dk</email>
9727 The Hacker's Jargon File has the following to say about the
9729 prefix "YA" in the name of a software product.
9733 Yet Another. adj. 1. Of your own work: A
9734 humorous allusion often used in titles to acknowledge that the
9735 topic is not original, though the content is. As in "Yet Another
9736 AI Group" or "Yet Another Simulated Annealing Algorithm".
9738 others' work: Describes something of which there are already far
9743 <appendix id="credits">
9744 <title>Credits</title>
9746 This appendix lists individuals that have contributed in the development
9747 of &yaz;. Some have contributed with code, while others have provided bug
9748 fixes or suggestions. If we're missing somebody, of if you, for
9749 whatever reason, don't like to be listed here, let us know.
9759 Morten Bøgeskov
9780 Mads Bondo Dydensborg
9789 Morten Garkier Hendriksen
9846 Tom André Øverland
9852 <!-- Keep this comment at the end of the file
9855 nxml-child-indent: 1