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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>,
386 <ulink url="&url.solaris;">Solaris</ulink>,
387 Windows 7, Windows XP.
390 Some versions have be known to work on HP/UX,
391 DEC Unix, <ulink url="&url.netbsd;">NetBSD</ulink>,
392 <ulink url="&url.openbsd;">OpenBSD</ulink>,
394 Data General DG/UX (with some CFLAGS tinkering),
395 SGI/IRIX, DDE Supermax, Apple Macintosh (using the Codewarrior programming
396 environment and the GUSI socket libraries),
400 If you move the software to other platforms, we'd be grateful if you'd
401 let us know about it. If you run into difficulties, we will try to help
402 if we can, and if you solve the problems, we would be happy to include
403 your fixes in the next release. So far, we have mostly avoided
404 <literal>#ifdefs</literal> for individual platforms, and we'd
405 like to keep it that way as far as it makes sense.
408 We maintain a mailing-list for the purpose of announcing new releases and
409 bug-fixes, as well as general discussion. Subscribe by
411 <ulink url="&url.yaz.mailinglist;">here</ulink>.
412 General questions and problems can be directed at
413 <ulink url="&url.yaz.mail;"/>, or the address given at the top of
417 <sect1 id="installation.unix"><title>UNIX</title>
420 <ulink url="&url.debian;">Debian GNU/Linux</ulink> (i386 and amd64),
421 <ulink url="&url.ubuntu;">Ubuntu</ulink> (i386 and amd64)
423 <ulink url="&url.centos;">CentOS</ulink> (amd64 only) packages for &yaz;.
424 You should be able to create packages for other CPUs by building
425 them from the source package.
428 YAZ is also part of several packages repositories. Some of them are
433 Solaris CSW: <ulink url="http://www.opencsw.org/packages/yaz/"/>
438 Solaris: <ulink url="http://unixpackages.com"/>
443 FreeBSD: <ulink url="http://www.freshports.org/net/yaz"/>
448 Debian: <ulink url="http://packages.debian.org/search?keywords=yaz"/>
453 Ubuntu: <ulink url="https://launchpad.net/ubuntu/+source/yaz"/>
459 <ulink url="http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/net/yaz/README.html"/>
463 <sect2 id="installation.source.unix">
464 <title>Compiling from source on Unix</title>
466 Note that if your system doesn't have a native ANSI C compiler, you may
467 have to acquire one separately. We recommend
468 <ulink url="&url.gcc;">GCC</ulink>.
471 If you wish to use character set conversion facilities in &yaz; or if you
472 are compiling &yaz; for use with Zebra it is a good idea to ensure that
473 the iconv library is installed. Some Unixes today already have it
475 <ulink url="&url.libiconv;">GNU libiconv</ulink>.
478 YAZ 3.0.16 and later includes a wrapper for the
479 <ulink url="&url.icu;">ICU</ulink>
480 (International Components for Unicode).
481 In order to use this, the developer version of the ICU library
482 must be available. ICU support is recommended for applications
483 such as Pazpar2 and Zebra.
486 The <ulink url="&url.libxslt;">libxslt</ulink>,
487 <ulink url="&url.libxml2;">libxml2</ulink> librararies are required
488 if &yaz; is to support SRU/Solr.
489 These libraries are very portable and should compile out-of-the
490 box on virtually all Unix platforms. It is available in binary
491 forms for Linux and others.
495 <ulink url="&url.autoconf;">Autoconf</ulink>,
496 <ulink url="&url.automake;">Automake</ulink> and
497 <ulink url="&url.libtool;">Libtool</ulink>
498 are used to generate Makefiles and configure &yaz; for the system.
499 You do <emphasis>not</emphasis> need these tools unless you're using the
500 Git version of &yaz;.
503 The CQL parser for &yaz; is built using
504 GNU <ulink url="&url.bison;">Bison</ulink>.
505 This tool is only needed if you're using the Git version of &yaz;.
508 &yaz; includes a tiny ASN.1 compiler. This compiler is
509 written in <ulink url="&url.tcl;">Tcl</ulink>.
510 But as for Bison you do not need it unless you're using Git
511 version of &yaz; or you're using the compiler to build your own codecs
515 Generally it should be sufficient to run configure without options,
522 The configure script attempts to use use the C compiler specified by
523 the <literal>CC</literal> environment variable. If not set, GNU C will be
524 used if it is available. The <literal>CFLAGS</literal> environment
525 variable holds options to be passed to the C compiler. If you're using
526 Bourne-compatible shell you may pass something like this to use a
527 particular C compiler with optimization enabled:
530 CC=/opt/ccs/bin/cc CFLAGS=-O ./configure
533 To customize &yaz;, the configure script also accepts a set of options.
534 The most important are:
538 <literal>--prefix</literal>=<replaceable>prefix</replaceable>
541 <para>Specifies installation prefix for &yaz;. This is
542 only needed if you run <literal>make install</literal> later to
543 perform a "system" installation. The prefix is
544 <literal>/usr/local</literal> if not specified.
550 <literal>--enable-tcpd</literal>
553 <para>The front end server will be built using Wietse's
554 <ulink url="&url.tcpwrapper;">TCP wrapper library</ulink>.
555 It allows you to allow/deny clients depending on IP number.
556 The TCP wrapper library is often used in GNU/Linux and
560 <refentrytitle>hosts_access</refentrytitle>
561 <manvolnum>5</manvolnum>
565 <refentrytitle>tcpd</refentrytitle>
566 <manvolnum>8</manvolnum>
573 <literal>--enable-threads</literal>
576 <para>&yaz; will be built using POSIX threads.
577 Specifically, <constant>_REENTRANT</constant> will be defined during
584 <literal>--disable-shared</literal>
587 <para>The make process will not create shared
588 libraries (also known as shared objects <filename>.so</filename>).
589 By default, shared libraries are created -
590 equivalent to <literal>--enable-shared</literal>.
596 <literal>--disable-shared</literal>
599 <para>The make process will not create
600 static libraries (<filename>.a</filename>).
601 By default, static libraries are created -
602 equivalent to <literal>--enable-static</literal>.
608 <literal>--with-iconv</literal>[=<replaceable>prefix</replaceable>]
611 <para>Compile &yaz; with iconv library in directory
612 <replaceable>prefix</replaceable>. By default configure will
613 search for iconv on the system. Use this option if it
614 doesn't find iconv. Alternatively,
615 <literal>--without-iconv</literal>, can be used to force &yaz;
622 <literal>--with-xslt</literal>[=<replaceable>prefix</replaceable>]
625 <para>Compile &yaz; with
626 <ulink url="&url.libxslt;">libxslt</ulink> in directory
627 <replaceable>prefix</replaceable>.
628 Use this option if you want XSLT and XML support.
629 By default, configure will
630 search for libxslt on the system. Use this option if
631 libxslt is not found automatically. Alternatively,
632 <literal>--without-xslt</literal>, can be used to force &yaz;
639 <literal>--with-xml2</literal>[=<replaceable>prefix</replaceable>]
642 <para>Compile &yaz; with
643 <ulink url="&url.libxml2;">libxml2</ulink> in directory
644 <replaceable>prefix</replaceable>.
645 Use this option if you want &yaz; to use XML and support SRU/Solr.
646 By default, configure will
647 search for libxml2 on the system. Use this option if
648 libxml2 is not found automatically. Alternatively,
649 <literal>--without-xml2</literal>, can be used to force &yaz;
653 Note that option <literal>--with-xslt</literal>
654 also enables libxml2.
660 <literal>--with-gnutls</literal>[=<replaceable>prefix</replaceable>]
663 <para>&yaz; will be linked with the GNU TLS libraries and
664 an SSL COMSTACK will be provided. By default configure enables
665 SSL support for YAZ if the GNU TLS development libraries are found
672 <literal>--with-icu</literal>[=<replaceable>prefix</replaceable>]
675 <para>&yaz; will be linked the
676 <ulink url="&url.icu;">ICU</ulink> library in the prefix if given.
677 If prefix is not given, the libraries exposed by the script
678 <application>icu-config</application> will be used if found.
685 <literal>--with-libgcrypt</literal>[=<replaceable>prefix</replaceable>]
688 <para>&yaz; will be linked with
689 <ulink url="&url.libgcrypt;">Libgcrypt</ulink> in the prefix if given.
690 If prefix is not given, the libraries exposed by the script
691 <application>libgcrypt-config</application> will be used if found.
697 <literal>--with-memcached</literal>
700 <para>&yaz; will be linked with
701 <ulink url="&url.libmemcached;">libMemcached</ulink> to allow
702 for result-set caching for ZOOM.
703 The prefix can not be given. Note that YAZ will only search
704 for libMemcached if Libgcrypt is also enabled.
705 Note that 0.40 of libmemcached is required.
711 <literal>--with-redis</literal>
714 <para>&yaz; will be linked with the hiredis C library
715 to allow for result-set caching for ZOOM on a
716 <ulink url="&url.redis;">redis</ulink> server.
717 The prefix can not be given. Note that YAZ will only search
718 for hiredis if Libgcrypt is also enabled.
726 When configured, build the software by typing:
732 The following files are generated by the make process:
735 <term><filename>src/libyaz.la</filename></term>
737 Main &yaz; library. This is no ordinary library. It's
739 By default, &yaz; creates a static library in
740 <filename>lib/.libs/libyaz.a</filename>.
744 <term><filename>src/libyaz_server.la</filename></term>
746 Generic Frontend server. This is an add-on for libyaz.la.
747 Code in this library uses POSIX threads functions - if POSIX
748 threads are available on the platform.
752 <term><filename>src/libyaz_icu.la</filename></term>
754 Functions that wrap the ICU library.
758 <term><filename>ztest/yaz-ztest</filename></term>
759 <listitem><para>Test Z39.50 server.
763 <term><filename>client/yaz-client</filename></term>
764 <listitem><para>Z39.50 client for testing the protocol.
765 See chapter <link linkend="yaz-client">
766 YAZ client</link> for more information.
770 <term><filename>util/yaz-config</filename></term>
771 <listitem><para>A Bourne-shell script, generated by configure, that
772 specifies how external applications should compile - and link with
777 <term><filename>util/yaz-asncomp</filename></term>
778 <listitem><para>The ASN.1 compiler for &yaz;. Requires the
779 Tcl Shell, <application>tclsh</application>, in
780 <literal>PATH</literal> to operate.
784 <term><filename>util/yaz-iconv</filename></term>
785 <listitem><para>This program converts data in one character set to
786 another. This command exercises the YAZ character set
791 <term><filename>util/yaz-marcdump</filename></term>
792 <listitem><para>This program parses ISO2709 encoded MARC records
793 and prints them in line-format or XML.
797 <term><filename>util/yaz-icu</filename></term>
798 <listitem><para>This program exposes the ICU wrapper library if that
799 is enabled for YAZ. Only if ICU is available this program is
804 <term><filename>util/yaz-url</filename></term>
805 <listitem><para>This program is a simple HTTP page fetcher ala
810 <term><filename>zoom/zoomsh</filename></term>
812 A simple shell implemented on top of the
813 <link linkend="zoom">ZOOM</link> functions.
814 The shell is a command line application that allows you to enter
815 simple commands to perform ZOOM operations.
819 <term><filename>zoom/zoomtst1</filename>,
820 <filename>zoom/zoomtst2</filename>, ..</term>
822 Several small applications that demonstrates the ZOOM API.
828 If you wish to install &yaz; in system directories
829 <filename>/usr/local/bin</filename>,
830 <filename>/usr/local/lib</filename> .. etc, you can type:
836 You probably need to have root access in order to perform this.
837 You must specify the <literal>--prefix</literal> option for configure if
838 you wish to install &yaz; in other directories than the default
839 <filename>/usr/local/</filename>.
842 If you wish to perform an un-installation of &yaz;, use:
848 This will only work if you haven't reconfigured &yaz; (and therefore
849 changed installation prefix). Note that uninstall will not
850 remove directories created by make install, e.g.
851 <filename>/usr/local/include/yaz</filename>.
854 <sect2 id="installation-linking-yaz-unix">
855 <title>How to make apps using YAZ on UNIX</title>
857 This section describes how to compile - and link your own
858 applications using the &yaz; toolkit.
859 If you're used to Makefiles this shouldn't be hard. As for
860 other libraries you have used before, you need to set a proper include
861 path for your C/C++ compiler and specify the location of
862 &yaz; libraries. You can do it by hand, but generally we suggest
863 you use the <filename>yaz-config</filename> that is generated
864 by <filename>configure</filename>. This is especially
865 important if you're using the threaded version of &yaz; which
866 require you to pass more options to your linker/compiler.
869 The <filename>yaz-config</filename> script accepts command line
870 options that makes the <filename>yaz-config</filename> script print
871 options that you should use in your make process.
872 The most important ones are:
873 <literal>--cflags</literal>, <literal>--libs</literal>
874 which prints C compiler flags, and linker flags respectively.
877 A small and complete <literal>Makefile</literal> for a C
878 application consisting of one source file,
879 <filename>myprog.c</filename>, may look like this:
881 YAZCONFIG=/usr/local/bin/yaz-config
882 CFLAGS=`$(YAZCONFIG) --cflags`
883 LIBS=`$(YAZCONFIG) --libs`
885 $(CC) $(CFLAGS) -o myprog myprog.o $(LIBS)
889 The CFLAGS variable consists of a C compiler directive that will set
890 the include path to the <emphasis>parent</emphasis> directory
891 of <filename>yaz</filename>. That is, if &yaz; header files were
892 installed in <filename>/usr/local/include/yaz</filename>,
893 then include path is set to <filename>/usr/local/include</filename>.
894 Therefore, in your applications you should use
896 #include <yaz/proto.h>
898 and <emphasis>not</emphasis>
900 #include <proto.h>
904 For Libtool users, the <filename>yaz-config</filename> script provides
905 a different variant of option <literal>--libs</literal>, called
906 <literal>--lalibs</literal> that returns the name of the
907 Libtool archive(s) for &yaz; rather than the ordinary ones.
910 For applications using the threaded version of &yaz;,
911 specify <literal>threads</literal> after the
912 other options. When <literal>threads</literal> is given,
913 more flags and linker flags will be printed by
914 <filename>yaz-config</filename>. If our previous example was
915 using threads, you'd have to modify the lines that set
916 <literal>CFLAGS</literal> and <literal>LIBS</literal> as
919 CFLAGS=`$(YAZCONFIG) --cflags threads`
920 LIBS=`$(YAZCONFIG) --libs threads`
922 There is no need specify POSIX thread libraries in your Makefile.
923 The <literal>LIBS</literal> variable includes that as well.
927 <sect1 id="installation.win32">
928 <title>Windows</title>
929 <para>The easiest way to install YAZ on Windows is by downloading
931 <ulink url="&url.yaz.download.win32;">here</ulink>.
932 The installer comes with source too - in case you wish to
933 compile YAZ with different compiler options, etc.
936 <sect2 id="installation.win32.source">
937 <title>Compiling from Source on Windows</title>
939 &yaz; is shipped with "makefiles" for the NMAKE tool that comes
940 with <ulink url="&url.vstudio;">
941 Microsoft Visual Studio</ulink>. It has been tested with
942 Microsoft Visual Studio 2013.
945 Start a command prompt and switch the sub directory
946 <filename>WIN</filename> where the file <filename>makefile</filename>
947 is located. Customize the installation by editing the
948 <filename>makefile</filename> file (for example by using notepad).
949 The following summarizes the most important settings in that file:
952 <term><literal>DEBUG</literal></term>
954 If set to 1, the software is
955 compiled with debugging libraries (code generation is
956 multi-threaded debug DLL).
957 If set to 0, the software is compiled with release libraries
958 (code generation is multi-threaded DLL).
962 <term><literal>HAVE_TCL</literal>, <literal>TCL</literal></term>
964 If <literal>HAVE_TCL</literal> is set to 1, nmake will
965 use the ASN.1 compiler (<ulink url="&url.tcl;">Tcl</ulink> based).
966 You must set <literal>TCL</literal> to the full path of the Tcl
967 interpreter. A Windows version of Tcl is part of
968 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
971 If you do not have Tcl installed, set
972 <literal>HAVE_TCL</literal> to 0.
976 <term><literal>HAVE_BISON</literal>,
977 <literal>BISON</literal></term>
979 If GNU Bison is present, you might set <literal>HAVE_BISON</literal>
980 to 1 and specify the Bison executable in <literal>BISON</literal>.
981 Bison is only required if you use the Git version of
982 YAZ or if you modify the grammar for CQL
983 (<filename>cql.y</filename>).
986 A Windows version of GNU Bison is part of
987 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
991 <term><literal>HAVE_ICONV</literal>,
992 <literal>ICONV_DIR</literal></term>
994 If <literal>HAVE_ICONV</literal> is set to 1, YAZ is compiled
995 with iconv support. In this configuration, set
996 <literal>ICONV_DIR</literal> to the iconv source directory.
1000 <term><literal>HAVE_LIBXML2</literal>,
1001 <literal>LIBXML2_DIR</literal></term>
1004 If <literal>HAVE_LIBXML2</literal> is set to 1, YAZ is compiled
1005 with SRU support. In this configuration, set
1006 <literal>LIBXML2_DIR</literal> to the
1007 <ulink url="&url.libxml2;">libxml2</ulink> source directory.
1010 You can get pre-compiled Libxml2+Libxslt DLLs and headers from
1011 <ulink url="&url.libxml2.download.windows;">here</ulink>.
1012 Should you with to compile those libraries yourself, refer to
1013 to <xref linkend="installation.windows.libxml2"/>
1018 <term><literal>HAVE_LIBXSLT</literal>,
1019 <literal>LIBXSLT_DIR</literal></term>
1022 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1023 with XSLT support. In this configuration, set
1024 <literal>LIBXSLT_DIR</literal> to the
1025 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1029 libxslt depends on libxml2.
1035 <term><literal>HAVE_ICU</literal>,
1036 <literal>ICU_DIR</literal></term>
1039 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1040 with <ulink url="&url.icu;">ICU</ulink> support.
1041 In this configuration, set
1042 <literal>ICU_DIR</literal> to the
1043 <ulink url="&url.icu;">ICU</ulink> source directory.
1050 When satisfied with the settings in the makefile, type
1057 If the <filename>nmake</filename> command is not found on your system
1058 you probably haven't defined the environment variables required to
1059 use that tool. To fix that, find and run the batch file
1060 <filename>vcvars32.bat</filename>. You need to run it from within
1061 the command prompt or set the environment variables "globally";
1062 otherwise it doesn't work.
1066 If you wish to recompile &yaz; - for example if you modify
1067 settings in the <filename>makefile</filename> you can delete
1068 object files, etc by running.
1074 The following files are generated upon successful compilation:
1077 <term><filename>bin/yaz&soversion;.dll</filename> /
1078 <filename>bin/yaz&soversion;d.dll</filename></term>
1080 &yaz; Release/Debug DLL.
1084 <term><filename>lib/yaz&soversion;.lib</filename> /
1085 <filename>lib/yaz&soversion;d.lib</filename></term>
1087 Import library for <filename>yaz&soversion;.dll</filename> /
1088 <filename>yaz&soversion;d.dll</filename>.
1092 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1093 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1095 Release/Debug DLL for condition variable utilities (condvar.c).
1099 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1100 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1102 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1103 <filename>yaz_cond&soversion;d.dll</filename>.
1107 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1108 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1110 Release/Debug DLL for the ICU wrapper utility.
1111 Only build if HAVE_ICU is 1.
1115 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1116 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1118 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1119 <filename>yaz_icu&soversion;d.dll</filename>.
1123 <term><filename>bin/yaz-ztest.exe</filename></term>
1125 Z39.50 multi-threaded test/example server. It's a WIN32
1126 console application.
1130 <term><filename>bin/yaz-client.exe</filename></term>
1132 &yaz; Z39.50 client application. It's a WIN32 console application.
1133 See chapter <link linkend="yaz-client">YAZ client</link> for more
1138 <term><filename>bin/yaz-icu.exe</filename></term>
1139 <listitem><para>This program exposes the ICU wrapper library if that
1140 is enabled for YAZ. Only if ICU is available this program is
1145 <term><filename>bin/zoomsh.exe</filename></term>
1147 Simple console application implemented on top of the
1148 <link linkend="zoom">ZOOM</link> functions.
1149 The application is a command line shell that allows you to enter
1150 simple commands to perform ZOOM operations.
1154 <term><filename>bin/zoomtst1.exe</filename>,
1155 <filename>bin/zoomtst2.exe</filename>, ..</term>
1157 Several small applications that demonstrate the ZOOM API.
1164 <sect2 id="installation-linking-yaz-win32">
1165 <title>How to make apps using YAZ on Windows</title>
1167 This section will go though the process of linking your Windows
1168 applications with &yaz;.
1171 Some people are confused by the fact that we use the nmake
1172 tool to build &yaz;. They think they have to do that too - in order
1173 to make their Windows applications work with &yaz;. The good news is that
1174 you don't have to. You can use the integrated environment of
1175 Visual Studio if desired for your own application.
1178 When setting up a project or Makefile you have to set the following:
1181 <term>include path</term>
1183 Set it to the <filename>include</filename> directory of &yaz;.
1187 <term>import library <filename>yaz&soversion;.lib</filename></term>
1189 You must link with this library. It's located in the
1190 sub directory <filename>lib</filename> of &yaz;.
1191 If you want to link with the debug version of &yaz;, you must
1192 link against <filename>yaz&soversion;d.lib</filename> instead.
1196 <term>dynamic link library
1197 <filename>yaz&soversion;.dll</filename>
1200 This DLL must be in your execution path when you invoke
1201 your application. Specifically, you should distribute this
1202 DLL with your application.
1209 <sect2 id="installation.windows.libxml2">
1210 <title>Compiling Libxml2 and Libxslt on windows</title>
1212 Download libxml2 and Libxslt source and unpack it.
1213 In the example below we install Libxml2 2.9.2 and Libxslt 1.1.28
1214 for 32-bit, so we use the destination directories
1215 libxml2.2.9.2.win32 and libxslt-1.1.28.win32 to reflect both
1216 version and architecture.
1219 cscript configure.js prefix=c:\libxml2-2.9.2.win32 iconv=no
1226 There's an error in <filename>configure.js</filename> for Libxml2 2.9.2.
1227 Line 17 should be assigned to <filename>configure.ac</filename>
1228 rather than <filename>configure.in</filename>.
1232 For Libxslt it is similar. We must ensure that compilation of
1233 Libxslt links against the already installed libxml2.
1236 cscript configure.js prefix=c:\libxslt-1.1.28.win32 iconv=no \
1237 lib=c:\libxml2-2.9.2.win32\lib \
1238 include=c:\libxml2-2.9.2.win32\include\libxml2
1248 ### Still to document:
1249 ZOOM_connection_errcode(c)
1250 ZOOM_connection_errmsg(c)
1251 ZOOM_connection_addinfo(c)
1252 ZOOM_connection_addinfo(c)
1253 ZOOM_connection_diagset(c);
1254 ZOOM_connection_save_apdu_wrbuf
1255 ZOOM_diag_str(error)
1256 ZOOM_resultset_record_immediate(s, pos)
1257 ZOOM_resultset_cache_reset(r)
1258 ZOOM_options_set_callback(opt, function, handle)
1259 ZOOM_options_create_with_parent2(parent1, parent2)
1260 ZOOM_options_getl(opt, name, len)
1261 ZOOM_options_setl(opt, name, value, len)
1262 ZOOM_options_get_bool(opt, name, defa)
1263 ZOOM_options_get_int(opt, name, defa)
1264 ZOOM_options_set_int(opt, name, value)
1269 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1270 an initiative started by Mike Taylor (Mike is from the UK, which
1271 explains the peculiar name of the model). The goal of &zoom; is to
1272 provide a common Z39.50 client API not bound to a particular
1273 programming language or toolkit.
1276 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1277 You can make SRU ZOOM connections by specifying scheme
1278 <literal>http://</literal> for the hostname for a connection.
1279 The dialect of SRU used is specified by the value of the
1280 connection's <literal>sru</literal> option, which may be SRU over
1281 HTTP GET (<literal>get</literal>),
1282 SRU over HTTP POST (<literal>post</literal>), (SRU over
1283 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1284 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1285 Using the facility for embedding options in target strings, a
1286 connection can be forced to use SRU rather the SRW (the default) by
1287 prefixing the target string with <literal>sru=get,</literal>, like this:
1288 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1291 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1292 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1293 HTTP based protocols.
1296 The lack of a simple Z39.50 client API for &yaz; has become more
1297 and more apparent over time. So when the first &zoom; specification
1299 an implementation for &yaz; was quickly developed. For the first time, it is
1300 now as easy (or easier!) to develop clients than servers with &yaz;. This
1301 chapter describes the &zoom; C binding. Before going further, please
1302 reconsider whether C is the right programming language for the job.
1303 There are other language bindings available for &yaz;, and still
1305 are in active development. See the
1306 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1310 In order to fully understand this chapter you should read and
1311 try the example programs <literal>zoomtst1.c</literal>,
1312 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1316 The C language misses features found in object oriented languages
1317 such as C++, Java, etc. For example, you'll have to manually,
1318 destroy all objects you create, even though you may think of them as
1319 temporary. Most objects has a <literal>_create</literal> - and a
1320 <literal>_destroy</literal> variant.
1321 All objects are in fact pointers to internal stuff, but you don't see
1322 that because of typedefs. All destroy methods should gracefully ignore a
1323 <literal>NULL</literal> pointer.
1326 In each of the sections below you'll find a sub section called
1327 protocol behavior, that describes how the API maps to the Z39.50
1330 <sect1 id="zoom-connections">
1331 <title>Connections</title>
1332 <para>The Connection object is a session with a target.
1335 #include <yaz/zoom.h>
1337 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1339 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1341 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1343 void ZOOM_connection_destroy(ZOOM_connection c);
1346 Connection objects are created with either function
1347 <function>ZOOM_connection_new</function> or
1348 <function>ZOOM_connection_create</function>.
1349 The former creates and automatically attempts to establish a network
1350 connection with the target. The latter doesn't establish
1351 a connection immediately, thus allowing you to specify options
1352 before establishing network connection using the function
1353 <function>ZOOM_connection_connect</function>.
1354 If the port number, <literal>portnum</literal>, is zero, the
1355 <literal>host</literal> is consulted for a port specification.
1356 If no port is given, 210 is used. A colon denotes the beginning of
1357 a port number in the host string. If the host string includes a
1358 slash, the following part specifies a database for the connection.
1361 You can prefix the host with a scheme followed by colon. The
1362 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1363 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1364 but can overridded to use SRU/post, SRW and the Solr protocol.
1367 You can prefix the scheme-qualified host-string with one or more
1369 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1370 sequences, each of which represents an option to be set into the
1371 connection structure <emphasis>before</emphasis> the
1372 protocol-level connection is forged and the initialization
1373 handshake takes place. This facility can be used to provide
1374 authentication credentials, as in host-strings such as:
1375 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1378 Connection objects should be destroyed using the function
1379 <function>ZOOM_connection_destroy</function>.
1382 void ZOOM_connection_option_set(ZOOM_connection c,
1383 const char *key, const char *val);
1385 void ZOOM_connection_option_setl(ZOOM_connection c,
1387 const char *val, int len);
1389 const char *ZOOM_connection_option_get(ZOOM_connection c,
1391 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1396 The functions <function>ZOOM_connection_option_set</function> and
1397 <function>ZOOM_connection_option_setl</function> allows you to
1398 set an option given by <parameter>key</parameter> to the value
1399 <parameter>value</parameter> for the connection.
1400 For <function>ZOOM_connection_option_set</function>, the
1401 value is assumed to be a 0-terminated string. Function
1402 <function>ZOOM_connection_option_setl</function> specifies a
1403 value of a certain size (len).
1406 Functions <function>ZOOM_connection_option_get</function> and
1407 <function>ZOOM_connection_option_getl</function> returns
1408 the value for an option given by <parameter>key</parameter>.
1410 <table id="zoom-connection-options" frame="top">
1411 <title>ZOOM Connection Options</title>
1413 <colspec colwidth="4*" colname="name"></colspec>
1414 <colspec colwidth="7*" colname="description"></colspec>
1415 <colspec colwidth="3*" colname="default"></colspec>
1418 <entry>Option</entry>
1419 <entry>Description</entry>
1420 <entry>Default</entry>
1425 implementationName</entry><entry>Name of Your client
1426 </entry><entry>none</entry></row>
1428 user</entry><entry>Authentication user name
1429 </entry><entry>none</entry></row>
1431 group</entry><entry>Authentication group name
1432 </entry><entry>none</entry></row>
1434 password</entry><entry>Authentication password.
1435 </entry><entry>none</entry></row>
1437 authenticationMode</entry><entry>How authentication is encoded.
1438 </entry><entry>basic</entry></row>
1440 host</entry><entry>Target host. This setting is "read-only".
1441 It's automatically set internally when connecting to a target.
1442 </entry><entry>none</entry></row>
1444 proxy</entry><entry>Proxy host. If set, the logical host
1445 is encoded in the otherInfo area of the Z39.50 Init PDU
1446 with OID 1.2.840.10003.10.1000.81.1.
1447 </entry><entry>none</entry></row>
1449 clientIP</entry><entry>Client IP. If set, is
1450 encoded in the otherInfo area of a Z39.50 PDU with OID
1451 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1452 of a client. Is used of ZOOM is used in a gateway of some sort.
1453 </entry><entry>none</entry></row>
1455 async</entry><entry>If true (1) the connection operates in
1456 asynchronous operation which means that all calls are non-blocking
1458 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1459 </entry><entry>0</entry></row>
1461 maximumRecordSize</entry><entry> Maximum size of single record.
1462 </entry><entry>1 MB</entry></row>
1464 preferredMessageSize</entry><entry> Maximum size of multiple records.
1465 </entry><entry>1 MB</entry></row>
1467 lang</entry><entry> Language for negotiation.
1468 </entry><entry>none</entry></row>
1470 charset</entry><entry> Character set for negotiation.
1471 </entry><entry>none</entry></row>
1473 serverImplementationId</entry><entry>
1474 Implementation ID of server. (The old targetImplementationId
1475 option is also supported for the benefit of old applications.)
1476 </entry><entry>none</entry></row>
1478 targetImplementationName</entry><entry>
1479 Implementation Name of server. (The old
1480 targetImplementationName option is also supported for the
1481 benefit of old applications.)
1482 </entry><entry>none</entry></row>
1484 serverImplementationVersion</entry><entry>
1485 Implementation Version of server. (the old
1486 targetImplementationVersion option is also supported for the
1487 benefit of old applications.)
1488 </entry><entry>none</entry></row>
1490 databaseName</entry><entry>One or more database names
1491 separated by character plus (<literal>+</literal>), which to
1492 be used by subsequent search requests on this Connection.
1493 </entry><entry>Default</entry></row>
1495 piggyback</entry><entry>True (1) if piggyback should be
1496 used in searches; false (0) if not.
1497 </entry><entry>1</entry></row>
1499 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1500 value, then target will return all records using small element set name
1501 </entry><entry>0</entry></row>
1503 largeSetLowerBound</entry><entry>If hits is greater than this
1504 value, the target will return no records.
1505 </entry><entry>1</entry></row>
1507 mediumSetPresentNumber</entry><entry>This value represents
1508 the number of records to be returned as part of a search when when
1509 hits is less than or equal to large set lower bound and if hits
1510 is greater than small set upper bound.
1511 </entry><entry>0</entry></row>
1513 smallSetElementSetName</entry><entry>
1514 The element set name to be used for small result sets.
1515 </entry><entry>none</entry></row>
1517 mediumSetElementSetName</entry><entry>
1518 The element set name to be for medium-sized result sets.
1519 </entry><entry>none</entry></row>
1521 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1522 After a successful Init, these options may be interrogated to
1523 discover whether the server claims to support the specified
1525 </entry><entry>none</entry></row>
1527 <entry>sru</entry><entry>
1528 SRU/Solr transport type. Must be either <literal>soap</literal>,
1529 <literal>get</literal>, <literal>post</literal>, or
1530 <literal>solr</literal>.
1531 </entry><entry>soap</entry></row>
1533 sru_version</entry><entry>
1534 SRU/SRW version. Should be <literal>1.1</literal>, or
1535 <literal>1.2</literal>. This is , prior to connect, the version
1536 to offer (highest version). And following connect (in fact
1537 first operation), holds the negotiated version with the server
1538 (same or lower version).
1539 </entry><entry>1.2</entry></row>
1540 <row id="zoom.extraArgs.option"><entry>
1541 extraArgs</entry><entry>
1542 Extra arguments for SRU/Solr URLs. The value must be
1543 URL encoded already.
1544 </entry><entry></entry></row>
1545 <row id="zoom.facets.option"><entry>
1546 facets</entry><entry>
1547 Requested or recommend facets may be given before a search is sent.
1548 The value of this setting is described in <xref linkend="facets"/>
1549 For inspection of the facets returned, refer to the functions
1550 described in <xref linkend="zoom.facets"/>.
1551 </entry><entry>none</entry></row>
1553 apdulog</entry><entry>
1554 If set to a true value such as "1", a log of low-level
1555 protocol packets is emitted on standard error stream. This
1556 can be very useful for debugging.
1557 </entry><entry>0</entry></row>
1559 saveAPDU</entry><entry>
1560 If set to a true value such as "1", a log of low-level
1561 protocol packets is saved. The log can be retrieved by reading
1562 option APDU. Setting saveAPDU always has the side effect of
1563 resetting the currently saved log. This setting is
1564 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1565 It is only recognized in
1566 <function>ZOOM_connection_option_set</function>.
1567 </entry><entry>0</entry></row>
1570 Returns the log of protocol packets. Will be empty if logging
1571 is not enabled (see saveAPDU above). This setting is
1572 <emphasis>read-only</emphasis>. It is only recognized if used
1573 in call to <function>ZOOM_connection_option_get</function> or
1574 <function>ZOOM_connection_option_getl</function>.
1575 </entry><entry></entry></row>
1577 memcached</entry><entry>
1578 If given and non-empty,
1579 <ulink url="&url.libmemcached;">libMemcached</ulink>
1580 will be configured for the connection.
1581 This option is inspected by ZOOM when a connection is established.
1582 If the <literal>memcached</literal> option is given
1583 and YAZ is compiled without libMemcached support, an internal
1584 diagnostic (10018) will be thrown.
1585 libMemcached support is available for YAZ 5.0.13 or later. If this
1586 option is supplied for an earlier version of YAZ, it is
1587 <emphasis>ignored</emphasis>.
1588 The value of this option is a list options - each is of the
1589 form <literal>--name=value</literal>.
1590 Option <literal>--server=</literal>host[:port] specifies a memcached
1591 server. It may be repeated for multiple memcached servers.
1592 Option <literal>--expire=</literal>seconds sets expiry time in seconds
1593 for how long result sets are to be cached.
1594 </entry><entry>none</entry></row>
1596 redis</entry><entry>
1597 If given and non-empty,
1598 a <ulink url="&url.redis;">redis</ulink> context will be created
1600 This option is inspected by ZOOM when a connection is established.
1601 If the <literal>redis</literal> option is given
1602 and YAZ is compiled without redis support, an internal
1603 diagnostic (10018) will be thrown.
1604 redis support is available for YAZ 5.2.0 or later. If this
1605 option is supplied for an earlier version of YAZ, it is
1606 <emphasis>ignored</emphasis>.
1607 The value of this option is a set options, similar to that
1608 of the memcached setting. At this stage only --server=host[:port]
1609 and --expire=seconds is supported.
1610 </entry><entry>none</entry></row>
1615 If either option <literal>lang</literal> or <literal>charset</literal>
1617 <ulink url="&url.z39.50.charneg;">
1618 Character Set and Language Negotiation</ulink> is in effect.
1621 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1622 const char **addinfo);
1623 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1624 const char **addinfo, const char **dset);
1627 Function <function>ZOOM_connection_error</function> checks for
1628 errors for the last operation(s) performed. The function returns
1629 zero if no errors occurred; non-zero otherwise indicating the error.
1630 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1631 holds messages for the error and additional-info if passed as
1632 non-<literal>NULL</literal>. Function
1633 <function>ZOOM_connection_error_x</function> is an extended version
1634 of <function>ZOOM_connection_error</function> that is capable of
1635 returning name of diagnostic set in <parameter>dset</parameter>.
1637 <sect2 id="zoom-connection-z39.50">
1638 <title>Z39.50 Protocol behavior</title>
1640 The calls <function>ZOOM_connection_new</function> and
1641 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1642 connection and sends an Initialize Request to the target if
1643 possible. In addition, the calls waits for an Initialize Response
1644 from the target and the result is inspected (OK or rejected).
1647 If <literal>proxy</literal> is set then the client will establish
1648 a TCP/IP connection with the peer as specified by the
1649 <literal>proxy</literal> host and the hostname as part of the
1650 connect calls will be set as part of the Initialize Request.
1651 The proxy server will then "forward" the PDU's transparently
1652 to the target behind the proxy.
1655 For the authentication parameters, if option <literal>user</literal>
1656 is set and both options <literal>group</literal> and
1657 <literal>pass</literal> are unset, then Open style
1658 authentication is used (Version 2/3) in which case the username
1659 is usually followed by a slash, then by a password.
1660 If either <literal>group</literal>
1661 or <literal>pass</literal> is set then idPass authentication
1662 (Version 3 only) is used. If none of the options are set, no
1663 authentication parameters are set as part of the Initialize Request
1667 When option <literal>async</literal> is 1, it really means that
1668 all network operations are postponed (and queued) until the
1669 function <literal>ZOOM_event</literal> is invoked. When doing so
1670 it doesn't make sense to check for errors after
1671 <literal>ZOOM_connection_new</literal> is called since that
1672 operation "connecting - and init" is still incomplete and the
1673 API cannot tell the outcome (yet).
1676 <sect2 id="zoom.sru.init.behavior">
1677 <title>SRU/Solr Protocol behavior</title>
1679 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1680 Inititialize Request, so the connection phase merely establishes a
1681 TCP/IP connection with the HTTP server.
1683 <para>Most of the ZOOM connection options do not
1684 affect SRU/Solr and they are ignored. However, future versions
1685 of &yaz; might honor <literal>implementationName</literal> and
1686 put that as part of User-Agent header for HTTP requests.
1689 The <literal>charset</literal> is used in the Content-Type header
1693 Setting <literal>authentcationMode</literal> specifies how
1694 authentication parameters are encoded for HTTP. The default is
1695 "<literal>basic</literal>" where <literal>user</literal> and
1696 <literal>password</literal> are encoded by using HTTP basic
1700 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1701 user and password are encoded in the URL by parameters
1702 <literal>x-username</literal> and <literal>x-password</literal> as
1703 given by the SRU standard.
1707 <sect1 id="zoom.query">
1708 <title>Queries</title>
1710 Query objects represents queries.
1713 ZOOM_query ZOOM_query_create(void);
1715 void ZOOM_query_destroy(ZOOM_query q);
1717 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1719 int ZOOM_query_cql(ZOOM_query s, const char *str);
1721 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1723 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1724 const char *criteria);
1727 Create query objects using <function>ZOOM_query_create</function>
1728 and destroy them by calling <function>ZOOM_query_destroy</function>.
1729 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1730 notation by using the
1731 function <function>ZOOM_query_prefix</function>.
1732 The <function>ZOOM_query_cql</function> specifies a CQL
1733 query to be sent to the server/target.
1734 More query types will be added in future versions of &yaz;, such as
1735 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1736 etc. In addition to a search, a sort criteria may be set. Function
1737 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1738 it takes sort criteria using the same string notation as
1739 yaz-client's <link linkend="sortspec">sort command</link>.
1741 <para id="zoom.query.sortby2">
1742 <function>ZOOM_query_sortby2</function> is similar to
1743 <function>ZOOM_query_sortby</function> but allows a strategy for
1744 sorting. The reason for the strategy parameter is that some
1745 protocols offers multiple ways of performing sorting.
1746 For example, Z39.50 has the standard sort, which is performed after
1747 search on an existing result set.
1748 It's also possible to use CQL in Z39.50 as the query type and use
1749 CQL's SORTBY keyword. Finally, Index Data's
1750 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1752 <table id="zoom-sort-strategy" frame="top">
1753 <title>ZOOM sort strategy</title>
1755 <colspec colwidth="2*" colname="name"/>
1756 <colspec colwidth="5*" colname="description"/>
1760 <entry>Description</entry>
1765 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1768 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1771 <entry>cql</entry><entry>CQL SORTBY</entry>
1774 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1777 <entry>solr</entry><entry>Solr sort</entry>
1780 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1781 solr for Solr protocol</entry>
1787 <sect1 id="zoom.resultsets"><title>Result sets</title>
1789 The result set object is a container for records returned from
1793 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1795 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1797 void ZOOM_resultset_destroy(ZOOM_resultset r);
1800 Function <function>ZOOM_connection_search</function> creates
1801 a result set given a connection and query.
1802 Destroy a result set by calling
1803 <function>ZOOM_resultset_destroy</function>.
1804 Simple clients may using PQF only may use function
1805 <function>ZOOM_connection_search_pqf</function> in which case
1806 creating query objects is not necessary.
1809 void ZOOM_resultset_option_set(ZOOM_resultset r,
1810 const char *key, const char *val);
1812 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1814 size_t ZOOM_resultset_size(ZOOM_resultset r);
1817 Functions <function>ZOOM_resultset_options_set</function> and
1818 <function>ZOOM_resultset_get</function> sets and gets an option
1819 for a result set similar to <function>ZOOM_connection_option_get</function>
1820 and <function>ZOOM_connection_option_set</function>.
1823 The number of hits also called result-count is returned by
1824 function <function>ZOOM_resultset_size</function>.
1826 <table id="zoom.resultset.options"
1827 frame="top"><title>ZOOM Result set Options</title>
1829 <colspec colwidth="4*" colname="name"></colspec>
1830 <colspec colwidth="7*" colname="description"></colspec>
1831 <colspec colwidth="2*" colname="default"></colspec>
1834 <entry>Option</entry>
1835 <entry>Description</entry>
1836 <entry>Default</entry>
1841 start</entry><entry>Offset of first record to be
1842 retrieved from target. First record has offset 0 unlike the
1843 protocol specifications where first record has position 1.
1844 This option affects ZOOM_resultset_search and
1845 ZOOM_resultset_search_pqf and must be set before any of
1846 these functions are invoked. If a range of
1847 records must be fetched manually after search,
1848 function ZOOM_resultset_records should be used.
1849 </entry><entry>0</entry></row>
1851 count</entry><entry>Number of records to be retrieved.
1852 This option affects ZOOM_resultset_search and
1853 ZOOM_resultset_search_pqf and must be set before any of
1854 these functions are invoked.
1855 </entry><entry>0</entry></row>
1857 presentChunk</entry><entry>The number of records to be
1858 requested from the server in each chunk (present request). The
1859 value 0 means to request all the records in a single chunk.
1860 (The old <literal>step</literal>
1861 option is also supported for the benefit of old applications.)
1862 </entry><entry>0</entry></row>
1864 elementSetName</entry><entry>Element-Set name of records.
1865 Most targets should honor element set name <literal>B</literal>
1866 and <literal>F</literal> for brief and full respectively.
1867 </entry><entry>none</entry></row>
1869 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1870 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1871 </entry><entry>none</entry></row>
1873 schema</entry><entry>Schema for retrieval, such as
1874 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1875 </entry><entry>none</entry></row>
1877 setname</entry><entry>Name of Result Set (Result Set ID).
1878 If this option isn't set, the ZOOM module will automatically
1879 allocate a result set name.
1880 </entry><entry>default</entry></row>
1882 rpnCharset</entry><entry>Character set for RPN terms.
1883 If this is set, ZOOM C will assume that the ZOOM application is
1884 running UTF-8. Terms in RPN queries are then converted to the
1885 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1886 of RPN terms and no conversion is performed.
1887 </entry><entry>none</entry></row>
1892 For servers that support Search Info report, the following
1893 options may be read using <function>ZOOM_resultset_get</function>.
1894 This detailed information is read after a successful search has
1898 This information is a list of of items, where each item is
1899 information about a term or subquery. All items in the list
1901 <literal>SearchResult.</literal><replaceable>no</replaceable>
1902 where no presents the item number (0=first, 1=second).
1903 Read <literal>searchresult.size</literal> to determine the
1906 <table id="zoom.search.info.report.options"
1907 frame="top"><title>Search Info Report Options</title>
1909 <colspec colwidth="4*" colname="name"></colspec>
1910 <colspec colwidth="7*" colname="description"></colspec>
1913 <entry>Option</entry>
1914 <entry>Description</entry>
1919 <entry>searchresult.size</entry>
1921 number of search result entries. This option is-nonexistant
1922 if no entries are returned by the server.
1926 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1927 <entry>sub query ID</entry>
1930 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1931 <entry>result count for item (number of hits)</entry>
1934 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1935 <entry>subquery term</entry>
1939 searchresult.<replaceable>no</replaceable>.interpretation.term
1941 <entry>interpretation term</entry>
1945 searchresult.<replaceable>no</replaceable>.recommendation.term
1947 <entry>recommendation term</entry>
1952 <sect2 id="zoom.z3950.resultset.sort">
1953 <title>Z39.50 Result-set Sort</title>
1955 void ZOOM_resultset_sort(ZOOM_resultset r,
1956 const char *sort_type, const char *sort_spec);
1958 int ZOOM_resultset_sort1(ZOOM_resultset r,
1959 const char *sort_type, const char *sort_spec);
1962 <function>ZOOM_resultset_sort</function> and
1963 <function>ZOOM_resultset_sort1</function> both sort an existing
1964 result-set. The sort_type parameter is not use. Set it to "yaz".
1965 The sort_spec is same notation as ZOOM_query_sortby and identical
1966 to that offered by yaz-client's
1967 <link linkend="sortspec">sort command</link>.
1970 These functions only work for Z39.50. Use the more generic utility
1971 <link linkend="zoom.query.sortby2">
1972 <function>ZOOM_query_sortby2</function></link>
1973 for other protocols (and even Z39.50).
1976 <sect2 id="zoom.z3950.resultset.behavior">
1977 <title>Z39.50 Protocol behavior</title>
1979 The creation of a result set involves at least a SearchRequest
1980 - SearchResponse protocol handshake. Following that, if a sort
1981 criteria was specified as part of the query, a SortRequest -
1982 SortResponse handshake takes place. Note that it is necessary to
1983 perform sorting before any retrieval takes place, so no records will
1984 be returned from the target as part of the SearchResponse because these
1985 would be unsorted. Hence, piggyback is disabled when sort criteria
1986 are set. Following Search - and a possible sort - Retrieval takes
1987 place - as one or more Present Requests/Response pairs being
1991 The API allows for two different modes for retrieval. A high level
1992 mode which is somewhat more powerful and a low level one.
1993 The low level is enabled when searching on a Connection object
1994 for which the settings
1995 <literal>smallSetUpperBound</literal>,
1996 <literal>mediumSetPresentNumber</literal> and
1997 <literal>largeSetLowerBound</literal> are set. The low level mode
1998 thus allows you to precisely set how records are returned as part
1999 of a search response as offered by the Z39.50 protocol.
2000 Since the client may be retrieving records as part of the
2001 search response, this mode doesn't work well if sorting is used.
2004 The high-level mode allows you to fetch a range of records from
2005 the result set with a given start offset. When you use this mode
2006 the client will automatically use piggyback if that is possible
2007 with the target and perform one or more present requests as needed.
2008 Even if the target returns fewer records as part of a present response
2009 because of a record size limit, etc. the client will repeat sending
2010 present requests. As an example, if option <literal>start</literal>
2011 is 0 (default) and <literal>count</literal> is 4, and
2012 <literal>piggyback</literal> is 1 (default) and no sorting criteria
2013 is specified, then the client will attempt to retrieve the 4
2014 records as part the search response (using piggyback). On the other
2015 hand, if either <literal>start</literal> is positive or if
2016 a sorting criteria is set, or if <literal>piggyback</literal>
2017 is 0, then the client will not perform piggyback but send Present
2021 If either of the options <literal>mediumSetElementSetName</literal> and
2022 <literal>smallSetElementSetName</literal> are unset, the value
2023 of option <literal>elementSetName</literal> is used for piggyback
2024 searches. This means that for the high-level mode you only have
2025 to specify one elementSetName option rather than three.
2028 <sect2 id="zoom.sru.resultset.behavior">
2029 <title>SRU Protocol behavior</title>
2031 Current version of &yaz; does not take advantage of a result set id
2032 returned by the SRU server. Future versions might do, however.
2033 Since, the ZOOM driver does not save result set IDs any
2034 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2035 with same query but, possibly, different offsets.
2038 Option <literal>schema</literal> specifies SRU schema
2039 for retrieval. However, options <literal>elementSetName</literal> and
2040 <literal>preferredRecordSyntax</literal> are ignored.
2043 Options <literal>start</literal> and <literal>count</literal>
2044 are supported by SRU.
2045 The remaining options
2046 <literal>piggyback</literal>,
2047 <literal>smallSetUpperBound</literal>,
2048 <literal>largeSetLowerBound</literal>,
2049 <literal>mediumSetPresentNumber</literal>,
2050 <literal>mediumSetElementSetName</literal>,
2051 <literal>smallSetElementSetName</literal> are
2055 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2056 If PQF is used, however, the PQF query is transferred anyway
2057 using non-standard element <literal>pQuery</literal> in
2058 SRU SearchRetrieveRequest.
2061 Solr queries has to be done in Solr query format.
2064 Unfortunately, SRU or Solr does not define a database setting. Hence,
2065 <literal>databaseName</literal> is unsupported and ignored.
2066 However, the path part in host parameter for functions
2067 <function>ZOOM_connecton_new</function> and
2068 <function>ZOOM_connection_connect</function> acts as a
2069 database (at least for the &yaz; SRU server).
2073 <sect1 id="zoom.records">
2074 <title>Records</title>
2076 A record object is a retrieval record on the client side -
2077 created from result sets.
2080 void ZOOM_resultset_records(ZOOM_resultset r,
2082 size_t start, size_t count);
2083 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2085 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2088 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2089 const char **addinfo, const char **diagset);
2091 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2093 void ZOOM_record_destroy(ZOOM_record rec);
2096 References to temporary records are returned by functions
2097 <function>ZOOM_resultset_records</function> or
2098 <function>ZOOM_resultset_record</function>.
2101 If a persistent reference to a record is desired
2102 <function>ZOOM_record_clone</function> should be used.
2103 It returns a record reference that should be destroyed
2104 by a call to <function>ZOOM_record_destroy</function>.
2107 A single record is returned by function
2108 <function>ZOOM_resultset_record</function> that takes a
2109 position as argument. First record has position zero.
2110 If no record could be obtained <literal>NULL</literal> is returned.
2113 Error information for a record can be checked with
2114 <function>ZOOM_record_error</function> which returns non-zero
2115 (error code) if record is in error, called <emphasis>Surrogate
2116 Diagnostics</emphasis> in Z39.50.
2119 Function <function>ZOOM_resultset_records</function> retrieves
2120 a number of records from a result set. Parameter <literal>start</literal>
2121 and <literal>count</literal> specifies the range of records to
2122 be returned. Upon completion array
2123 <literal>recs[0], ..recs[count-1]</literal>
2124 holds record objects for the records. The array of records
2125 <literal>recs</literal> should be allocated prior the call
2126 <function>ZOOM_resultset_records</function>. Note that for those
2127 records that couldn't be retrieved from the target
2128 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2130 <para id="zoom.record.get">
2131 In order to extract information about a single record,
2132 <function>ZOOM_record_get</function> is provided. The
2133 function returns a pointer to certain record information. The
2134 nature (type) of the pointer depends on the parameter,
2135 <parameter>type</parameter>.
2138 The <parameter>type</parameter> is a string of the format:
2141 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>][;base64=<replaceable>xpath</replaceable>]
2144 If <literal>charset</literal> is given, then <replaceable>from</replaceable>
2145 specifies the character set of the record in its original form
2146 (as returned by the server), <replaceable>to</replaceable> specifies
2147 the output (returned) character set encoding.
2148 If <replaceable>to</replaceable> is omitted, then UTF-8 is assumed.
2149 If charset is not given, then no character set conversion takes place.
2150 OPAC records may be returned in a different
2151 set from the bibliographic MARC record. If this is this the case,
2152 <replaceable>opacfrom</replaceable> should be set to the character set
2153 of the OPAC record part.
2157 The <literal>format</literal> is generic but can only be used to
2158 specify XML indentation when the value <replaceable>v</replaceable>
2159 is 1 (<literal>format=1</literal>).
2162 The <literal>base64</literal> allows a full record to be extracted
2163 from base64-encoded string in an XML document.
2167 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2170 Specifying the base64 parameter requires YAZ 4.2.35 or later.
2174 The format argument controls whether record data should be XML
2175 pretty-printed (post process operation).
2176 It is enabled only if format value <replaceable>v</replaceable> is
2177 <literal>1</literal> and the record content is XML well-formed.
2180 In addition, for certain types, the length
2181 <literal>len</literal> passed will be set to the size in bytes of
2182 the returned information.
2185 The following are the supported values for <replaceable>form</replaceable>.
2187 <varlistentry><term><literal>database</literal></term>
2188 <listitem><para>Database of record is returned
2189 as a C null-terminated string. Return type
2190 <literal>const char *</literal>.
2193 <varlistentry><term><literal>syntax</literal></term>
2194 <listitem><para>The transfer syntax of the record is returned
2195 as a C null-terminated string containing the symbolic name of
2196 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2198 <literal>const char *</literal>.
2201 <varlistentry><term><literal>schema</literal></term>
2202 <listitem><para>The schema of the record is returned
2203 as a C null-terminated string. Return type is
2204 <literal>const char *</literal>.
2207 <varlistentry><term><literal>render</literal></term>
2208 <listitem><para>The record is returned in a display friendly
2209 format. Upon completion buffer is returned
2210 (type <literal>const char *</literal>) and length is stored in
2211 <literal>*len</literal>.
2214 <varlistentry><term><literal>raw</literal></term>
2215 <listitem><para>The record is returned in the internal
2216 YAZ specific format. For GRS-1, Explain, and others, the
2217 raw data is returned as type
2218 <literal>Z_External *</literal> which is just the type for
2219 the member <literal>retrievalRecord</literal> in
2220 type <literal>NamePlusRecord</literal>.
2221 For SUTRS and octet aligned record (including all MARCs) the
2222 octet buffer is returned and the length of the buffer.
2225 <varlistentry><term><literal>xml</literal></term>
2226 <listitem><para>The record is returned in XML if possible.
2227 SRU, Solr and Z39.50 records with transfer syntax XML are
2228 returned verbatim. MARC records are returned in
2229 <ulink url="&url.marcxml;">
2232 (converted from ISO2709 to MARCXML by YAZ).
2233 OPAC records are also converted to XML and the
2234 bibliographic record is converted to MARCXML (when possible).
2235 GRS-1 records are not supported for this form.
2236 Upon completion, the XML buffer is returned
2237 (type <literal>const char *</literal>) and length is stored in
2238 <literal>*len</literal>.
2241 <varlistentry><term><literal>opac</literal></term>
2242 <listitem><para>OPAC information for record is returned in XML
2243 if an OPAC record is present at the position given. If no
2244 OPAC record is present, a NULL pointer is returned.
2247 <varlistentry><term><literal>txml</literal></term>
2248 <listitem><para>The record is returned in TurboMARC if possible.
2249 SRU and Z39.50 records with transfer syntax XML are
2250 returned verbatim. MARC records are returned in
2251 <link linkend="tools.turbomarc">
2254 (converted from ISO2709 to TurboMARC by YAZ).
2255 Upon completion, the XML buffer is returned
2256 (type <literal>const char *</literal>) and length is stored in
2257 <literal>*len</literal>.
2260 <varlistentry><term><literal>json</literal></term>
2261 <listitem><para>Like xml, but MARC records are converted to
2262 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2270 <ulink url="&url.marc21;">MARC21</ulink>
2272 <ulink url="&url.marc8;">MARC-8</ulink>
2273 character set encoding.
2274 An application that wishes to display in Latin-1 would use
2276 render; charset=marc8,iso-8859-1
2279 <sect2 id="zoom.z3950.record.behavior">
2280 <title>Z39.50 Protocol behavior</title>
2282 The functions <function>ZOOM_resultset_record</function> and
2283 <function>ZOOM_resultset_records</function> inspects the client-side
2284 record cache. Records not found in cache are fetched using
2286 The functions may block (and perform network I/O) - even though option
2287 <literal>async</literal> is 1, because they return records objects.
2288 (and there's no way to return records objects without retrieving them!).
2291 There is a trick, however, in the usage of function
2292 <function>ZOOM_resultset_records</function> that allows for
2293 delayed retrieval (and makes it non-blocking). By using
2294 a null pointer for <parameter>recs</parameter> you're indicating
2295 you're not interested in getting records objects
2296 <emphasis>now</emphasis>.
2299 <sect2 id="zoom.sru.record.behavior">
2300 <title>SRU/Solr Protocol behavior</title>
2302 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2303 as if they where Z39.50 records with transfer syntax XML and
2304 no element set name or database name.
2308 <sect1 id="zoom.facets"><title>Facets</title>
2310 Facet operations is not part of the official ZOOM specification, but
2311 is an Index Data extension for YAZ-based Z39.50 targets,
2312 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2314 Facets may be requestd by the
2315 <link linkend="zoom.facets.option">facets</link> option before a
2317 For inspection of the returned facets, the following functions are
2321 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2323 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2324 const char *facet_name);
2326 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2329 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2331 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2333 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2335 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2336 size_t idx, int *freq);
2339 References to temporary structures are returned by all functions.
2340 They are only valid as long the Result set is valid.
2341 <function>ZOOM_resultset_get_facet_field</function> or
2342 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2343 <function>ZOOM_resultset_facets</function>.
2344 <function>ZOOM_facet_field_name</function>.
2345 <function>ZOOM_facet_field_get_term</function>.
2347 <para id="zoom.resultset.get_facet_field">
2348 A single Facet field is returned by function
2349 <function>ZOOM_resultset_get_facet_field</function> or
2350 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2351 a result set and facet name or positive index respectively. First
2352 facet has position zero. If no facet could be obtained (invalid name
2353 or index out of bounds) <literal>NULL</literal> is returned.
2355 <para id="zoom.resultset.facets">
2356 An array of facets field can be returned by
2357 <function>ZOOM_resultset_facets</function>. The length of the array is
2358 given by <function>ZOOM_resultset_facets_size</function>. The array is
2359 zero-based and last entry will be at
2360 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2362 <para id="zoom.resultset.facets_names">
2363 It is possible to interate over facets by name, by calling
2364 <function>ZOOM_resultset_facets_names</function>.
2365 This will return an const array of char * where each string can be used
2366 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2369 Function <function>ZOOM_facet_field_name</function> gets the request
2370 facet name from a returned facet field.
2373 Function <function>ZOOM_facet_field_get_term</function> returns the
2374 idx'th term and term count for a facet field.
2375 Idx must between 0 and
2376 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2377 returned reference will be <literal>NULL</literal>. On a valid idx, the
2378 value of the freq reference will be the term count.
2379 The <literal>freq</literal> parameter must be valid pointer to integer.
2382 <sect1 id="zoom.scan"><title>Scan</title>
2384 This section describes an interface for Scan. Scan is not an
2385 official part of the ZOOM model yet. The result of a scan operation
2386 is the <literal>ZOOM_scanset</literal> which is a set of terms
2387 returned by a target.
2391 The Scan interface is supported for both Z39.50, SRU and Solr.
2395 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2396 const char *startpqf);
2398 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2401 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2403 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2404 size_t *occ, size_t *len);
2406 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2407 size_t *occ, size_t *len);
2409 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2411 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2414 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2418 The scan set is created by function
2419 <function>ZOOM_connection_scan</function> which performs a scan
2420 operation on the connection using the specified
2421 <parameter>startpqf</parameter>.
2422 If the operation was successful, the size of the scan set can be
2423 retrieved by a call to <function>ZOOM_scanset_size</function>.
2424 Like result sets, the items are numbered 0,..size-1.
2425 To obtain information about a particular scan term, call function
2426 <function>ZOOM_scanset_term</function>. This function takes
2427 a scan set offset <literal>pos</literal> and returns a pointer
2428 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2430 If present, the <literal>occ</literal> and <literal>len</literal>
2431 are set to the number of occurrences and the length
2432 of the actual term respectively.
2433 <function>ZOOM_scanset_display_term</function> is similar to
2434 <function>ZOOM_scanset_term</function> except that it returns
2435 the <emphasis>display term</emphasis> rather than the raw term.
2436 In a few cases, the term is different from display term. Always
2437 use the display term for display and the raw term for subsequent
2438 scan operations (to get more terms, next scan result, etc).
2441 A scan set may be freed by a call to function
2442 <function>ZOOM_scanset_destroy</function>.
2443 Functions <function>ZOOM_scanset_option_get</function> and
2444 <function>ZOOM_scanset_option_set</function> retrieves and sets
2445 an option respectively.
2448 The <parameter>startpqf</parameter> is a subset of PQF, namely
2449 the Attributes+Term part. Multiple <literal>@attr</literal> can
2450 be used. For example to scan in title (complete) phrases:
2452 @attr 1=4 @attr 6=2 "science o"
2456 The <function>ZOOM_connecton_scan1</function> is a newer and
2457 more generic alternative to <function>ZOOM_connection_scan</function>
2458 which allows to use both CQL and PQF for Scan.
2460 <table frame="top" id="zoom.scanset.options">
2461 <title>ZOOM Scan Set Options</title>
2463 <colspec colwidth="4*" colname="name"></colspec>
2464 <colspec colwidth="7*" colname="description"></colspec>
2465 <colspec colwidth="2*" colname="default"></colspec>
2468 <entry>Option</entry>
2469 <entry>Description</entry>
2470 <entry>Default</entry>
2475 number</entry><entry>Number of Scan Terms requested in next scan.
2476 After scan it holds the actual number of terms returned.
2477 </entry><entry>20</entry></row>
2479 position</entry><entry>Preferred Position of term in response
2480 in next scan; actual position after completion of scan.
2481 </entry><entry>1</entry></row>
2483 stepSize</entry><entry>Step Size
2484 </entry><entry>0</entry></row>
2486 scanStatus</entry><entry>An integer indicating the Scan Status
2488 </entry><entry>0</entry></row>
2490 rpnCharset</entry><entry>Character set for RPN terms.
2491 If this is set, ZOOM C will assume that the ZOOM application is
2492 running UTF-8. Terms in RPN queries are then converted to the
2493 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2494 of RPN terms and no conversion is performed.
2495 </entry><entry>none</entry></row>
2500 <sect1 id="zoom.extendedservices">
2501 <title>Extended Services</title>
2503 ZOOM offers an interface to a subset of the Z39.50 extended services
2504 as well as a few privately defined ones:
2509 Z39.50 Item Order (ILL).
2510 See <xref linkend="zoom.item.order"/>.
2515 Record Update. This allows a client to insert, modify or delete
2517 See <xref linkend="zoom.record.update"/>.
2522 Database Create. This a non-standard feature. Allows a client
2523 to create a database.
2524 See <xref linkend="zoom.database.create"/>.
2529 Database Drop. This a non-standard feature. Allows a client
2530 to delete/drop a database.
2531 See <xref linkend="zoom.database.drop"/>.
2536 Commit operation. This a non-standard feature. Allows a client
2537 to commit operations.
2538 See <xref linkend="zoom.commit"/>.
2541 <!-- all the ILL PDU options should go here too -->
2544 To create an extended service operation a <literal>ZOOM_package</literal>
2545 must be created. The operation is a five step operation. The
2546 package is created, package is configured by means of options,
2547 the package is send, result is inspected (by means of options),
2548 the package is destroyed.
2551 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2552 ZOOM_options options);
2554 const char *ZOOM_package_option_get(ZOOM_package p,
2556 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2558 void ZOOM_package_send(ZOOM_package p, const char *type);
2560 void ZOOM_package_destroy(ZOOM_package p);
2563 The <function>ZOOM_connection_package</function> creates a
2564 package for the connection given using the options specified.
2567 Functions <function>ZOOM_package_option_get</function> and
2568 <function>ZOOM_package_option_set</function> gets and sets
2572 <function>ZOOM_package_send</function> sends
2573 the package the via connection specified in
2574 <function>ZOOM_connection_package</function>.
2575 The <parameter>type</parameter> specifies the actual extended service
2576 package type to be sent.
2578 <table frame="top" id="zoom.extendedservices.type">
2579 <title>Extended Service Type</title>
2581 <colspec colwidth="3*" colname="value"></colspec>
2582 <colspec colwidth="7*" colname="description"></colspec>
2586 <entry>Description</entry>
2591 <entry>itemorder</entry><entry>Item Order</entry>
2594 <entry>update</entry><entry>Record Update</entry>
2597 <entry>create</entry><entry>Database Create</entry>
2600 <entry>drop</entry><entry>Database Drop</entry>
2603 <entry>commit</entry><entry>Commit Operation</entry>
2609 <table frame="top" id="zoom.extendedservices.options">
2610 <title>Extended Service Common Options</title>
2612 <colspec colwidth="4*" colname="name"></colspec>
2613 <colspec colwidth="7*" colname="description"></colspec>
2614 <colspec colwidth="3*" colname="default"></colspec>
2617 <entry>Option</entry>
2618 <entry>Description</entry>
2619 <entry>Default</entry>
2624 <entry>package-name</entry>
2625 <entry>Extended Service Request package name. Must be specified
2626 as part of a request</entry>
2630 <entry>user-id</entry>
2631 <entry>User ID of Extended Service Package. Is a request option</entry>
2635 <entry>function</entry>
2637 Function of package - one of <literal>create</literal>,
2638 <literal>delete</literal>, <literal>modify</literal>. Is
2641 <entry><literal>create</literal></entry>
2644 <entry>waitAction</entry>
2646 Wait action for package. Possible values:
2647 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2648 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2650 <entry><literal>waitIfPossible</literal></entry>
2653 <entry>targetReference</entry>
2655 Target Reference. This is part of the response as returned
2656 by the server. Read it after a successful operation.
2658 <entry><literal>none</literal></entry>
2663 <sect2 id="zoom.item.order">
2664 <title>Item Order</title>
2666 For Item Order, <literal>type</literal> must be set to
2667 <literal>itemorder</literal> in
2668 <function>ZOOM_package_send</function>.
2671 <table frame="top" id="zoom.item.order.options">
2672 <title>Item Order Options</title>
2674 <colspec colwidth="4*" colname="name"></colspec>
2675 <colspec colwidth="7*" colname="description"></colspec>
2676 <colspec colwidth="3*" colname="default"></colspec>
2679 <entry>Option</entry>
2680 <entry>Description</entry>
2681 <entry>Default</entry>
2686 <entry>contact-name</entry>
2687 <entry>ILL contact name</entry>
2691 <entry>contact-phone</entry>
2692 <entry>ILL contact phone</entry>
2696 <entry>contact-email</entry>
2697 <entry>ILL contact email</entry>
2701 <entry>itemorder-setname</entry>
2702 <entry>Name of result set for record</entry>
2703 <entry>default</entry>
2706 <entry>itemorder-item</entry>
2707 <entry>Position for item (record) requested. An integer</entry>
2714 There are two variants of item order: ILL-variant and
2715 XML document variant. In order to use the XML variant the setting
2716 <literal>doc</literal> must hold the XML item order document. If that
2717 setting is unset, the ILL-variant is used.
2720 <table frame="top" id="zoom.illrequest.options">
2721 <title>ILL Request Options</title>
2723 <colspec colwidth="4*" colname="name"></colspec>
2726 <entry>Option</entry>
2730 <row><entry>protocol-version-num</entry></row>
2731 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,person</entry></row>
2732 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,institution</entry></row>
2733 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-person</entry></row>
2734 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2735 <row><entry>transaction-id,transaction-group-qualifier</entry></row>
2736 <row><entry>transaction-id,transaction-qualifier</entry></row>
2737 <row><entry>transaction-id,sub-transaction-qualifier</entry></row>
2738 <row><entry>service-date-time,this,date</entry></row>
2739 <row><entry>service-date-time,this,time</entry></row>
2740 <row><entry>service-date-time,original,date</entry></row>
2741 <row><entry>service-date-time,original,time</entry></row>
2742 <row><entry>requester-id,person-or-institution-symbol,person</entry></row>
2743 <row><entry>requester-id,person-or-institution-symbol,institution</entry></row>
2744 <row><entry>requester-id,name-of-person-or-institution,name-of-person</entry></row>
2745 <row><entry>requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2746 <row><entry>responder-id,person-or-institution-symbol,person</entry></row>
2747 <row><entry>responder-id,person-or-institution-symbol,institution</entry></row>
2748 <row><entry>responder-id,name-of-person-or-institution,name-of-person</entry></row>
2749 <row><entry>responder-id,name-of-person-or-institution,name-of-institution</entry></row>
2750 <row><entry>transaction-type</entry></row>
2751 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2752 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2753 <row><entry>delivery-address,postal-address,extended-postal-delivery-address</entry></row>
2754 <row><entry>delivery-address,postal-address,street-and-number</entry></row>
2755 <row><entry>delivery-address,postal-address,post-office-box</entry></row>
2756 <row><entry>delivery-address,postal-address,city</entry></row>
2757 <row><entry>delivery-address,postal-address,region</entry></row>
2758 <row><entry>delivery-address,postal-address,country</entry></row>
2759 <row><entry>delivery-address,postal-address,postal-code</entry></row>
2760 <row><entry>delivery-address,electronic-address,telecom-service-identifier</entry></row>
2761 <row><entry>delivery-address,electronic-address,telecom-service-addreess</entry></row>
2762 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2763 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2764 <row><entry>billing-address,postal-address,extended-postal-delivery-address</entry></row>
2765 <row><entry>billing-address,postal-address,street-and-number</entry></row>
2766 <row><entry>billing-address,postal-address,post-office-box</entry></row>
2767 <row><entry>billing-address,postal-address,city</entry></row>
2768 <row><entry>billing-address,postal-address,region</entry></row>
2769 <row><entry>billing-address,postal-address,country</entry></row>
2770 <row><entry>billing-address,postal-address,postal-code</entry></row>
2771 <row><entry>billing-address,electronic-address,telecom-service-identifier</entry></row>
2772 <row><entry>billing-address,electronic-address,telecom-service-addreess</entry></row>
2773 <row><entry>ill-service-type</entry></row>
2774 <row><entry>requester-optional-messages,can-send-RECEIVED</entry></row>
2775 <row><entry>requester-optional-messages,can-send-RETURNED</entry></row>
2776 <row><entry>requester-optional-messages,requester-SHIPPED</entry></row>
2777 <row><entry>requester-optional-messages,requester-CHECKED-IN</entry></row>
2778 <row><entry>search-type,level-of-service</entry></row>
2779 <row><entry>search-type,need-before-date</entry></row>
2780 <row><entry>search-type,expiry-date</entry></row>
2781 <row><entry>search-type,expiry-flag</entry></row>
2782 <row><entry>place-on-hold</entry></row>
2783 <row><entry>client-id,client-name</entry></row>
2784 <row><entry>client-id,client-status</entry></row>
2785 <row><entry>client-id,client-identifier</entry></row>
2786 <row><entry>item-id,item-type</entry></row>
2787 <row><entry>item-id,call-number</entry></row>
2788 <row><entry>item-id,author</entry></row>
2789 <row><entry>item-id,title</entry></row>
2790 <row><entry>item-id,sub-title</entry></row>
2791 <row><entry>item-id,sponsoring-body</entry></row>
2792 <row><entry>item-id,place-of-publication</entry></row>
2793 <row><entry>item-id,publisher</entry></row>
2794 <row><entry>item-id,series-title-number</entry></row>
2795 <row><entry>item-id,volume-issue</entry></row>
2796 <row><entry>item-id,edition</entry></row>
2797 <row><entry>item-id,publication-date</entry></row>
2798 <row><entry>item-id,publication-date-of-component</entry></row>
2799 <row><entry>item-id,author-of-article</entry></row>
2800 <row><entry>item-id,title-of-article</entry></row>
2801 <row><entry>item-id,pagination</entry></row>
2802 <row><entry>item-id,ISBN</entry></row>
2803 <row><entry>item-id,ISSN</entry></row>
2804 <row><entry>item-id,additional-no-letters</entry></row>
2805 <row><entry>item-id,verification-reference-source</entry></row>
2806 <row><entry>copyright-complicance</entry></row>
2807 <row><entry>retry-flag</entry></row>
2808 <row><entry>forward-flag</entry></row>
2809 <row><entry>requester-note</entry></row>
2810 <row><entry>forward-note</entry></row>
2815 <sect2 id="zoom.record.update">
2816 <title>Record Update</title>
2818 For Record Update, <literal>type</literal> must be set to
2819 <literal>update</literal> in
2820 <function>ZOOM_package_send</function>.
2822 <table frame="top" id="zoom.record.update.options">
2823 <title>Record Update Options</title>
2825 <colspec colwidth="4*" colname="name"></colspec>
2826 <colspec colwidth="7*" colname="description"></colspec>
2827 <colspec colwidth="3*" colname="default"></colspec>
2830 <entry>Option</entry>
2831 <entry>Description</entry>
2832 <entry>Default</entry>
2837 <entry>action</entry>
2839 The update action. One of
2840 <literal>specialUpdate</literal>,
2841 <literal>recordInsert</literal>,
2842 <literal>recordReplace</literal>,
2843 <literal>recordDelete</literal>,
2844 <literal>elementUpdate</literal>.
2846 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2849 <entry>recordIdOpaque</entry>
2850 <entry>Opaque Record ID</entry>
2854 <entry>recordIdNumber</entry>
2855 <entry>Record ID number</entry>
2859 <entry>record</entry>
2860 <entry>The record itself</entry>
2864 <entry>recordOpaque</entry>
2865 <entry>Specifies an opaque record which is
2866 encoded as an ASN.1 ANY type with the OID as tiven by option
2867 <literal>syntax</literal> (see below).
2868 Option <literal>recordOpaque</literal> is an alternative
2869 to record - and <literal>record</literal> option (above) is
2870 ignored if recordOpaque is set. This option is only available in
2871 YAZ 3.0.35 and later and is meant to facilitate Updates with
2877 <entry>syntax</entry>
2878 <entry>The record syntax (transfer syntax). Is a string that
2879 is a known record syntax.
2881 <entry>no syntax</entry>
2884 <entry>databaseName</entry>
2885 <entry>Database from connection object</entry>
2886 <entry>Default</entry>
2889 <entry>correlationInfo.note</entry>
2890 <entry>Correlation Info Note (string)</entry>
2894 <entry>correlationInfo.id</entry>
2895 <entry>Correlation Info ID (integer)</entry>
2899 <entry>elementSetName</entry>
2900 <entry>Element Set for Record</entry>
2904 <entry>updateVersion</entry>
2905 <entry>Record Update version which holds one of the values
2906 1, 2 or 3. Each version has a distinct OID:
2908 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2910 (second version) and
2911 1.2.840.10003.9.5.1.1
2912 (<ulink url="&url.z39.50.extupdate3;">third and
2913 newest version</ulink>).
2923 <sect2 id="zoom.database.create"><title>Database Create</title>
2925 For Database Create, <literal>type</literal> must be set to
2926 <literal>create</literal> in
2927 <function>ZOOM_package_send</function>.
2930 <table frame="top" id="zoom.database.create.options">
2931 <title>Database Create Options</title>
2933 <colspec colwidth="4*" colname="name"></colspec>
2934 <colspec colwidth="7*" colname="description"></colspec>
2935 <colspec colwidth="3*" colname="default"></colspec>
2938 <entry>Option</entry>
2939 <entry>Description</entry>
2940 <entry>Default</entry>
2945 <entry>databaseName</entry>
2946 <entry>Database from connection object</entry>
2947 <entry>Default</entry>
2953 <sect2 id="zoom.database.drop">
2954 <title>Database Drop</title>
2956 For Database Drop, <literal>type</literal> must be set to
2957 <literal>drop</literal> in
2958 <function>ZOOM_package_send</function>.
2960 <table frame="top" id="zoom.database.drop.options">
2961 <title>Database Drop Options</title>
2963 <colspec colwidth="4*" colname="name"></colspec>
2964 <colspec colwidth="7*" colname="description"></colspec>
2965 <colspec colwidth="3*" colname="default"></colspec>
2968 <entry>Option</entry>
2969 <entry>Description</entry>
2970 <entry>Default</entry>
2975 <entry>databaseName</entry>
2976 <entry>Database from connection object</entry>
2977 <entry>Default</entry>
2983 <sect2 id="zoom.commit">
2984 <title>Commit Operation</title>
2986 For Commit, <literal>type</literal> must be set to
2987 <literal>commit</literal> in
2988 <function>ZOOM_package_send</function>.
2991 <sect2 id="zoom.extended.services.behavior">
2992 <title>Protocol behavior</title>
2994 All the extended services are Z39.50-only.
2998 The database create, drop and commit services are privately defined
3000 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
3006 <sect1 id="zoom.options">
3007 <title>Options</title>
3009 Most &zoom; objects provide a way to specify options to change behavior.
3010 From an implementation point of view a set of options is just like
3011 an associative array / hash.
3014 ZOOM_options ZOOM_options_create(void);
3016 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
3018 void ZOOM_options_destroy(ZOOM_options opt);
3021 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
3023 void ZOOM_options_set(ZOOM_options opt, const char *name,
3027 typedef const char *(*ZOOM_options_callback)
3028 (void *handle, const char *name);
3030 ZOOM_options_callback
3031 ZOOM_options_set_callback(ZOOM_options opt,
3032 ZOOM_options_callback c,
3036 <sect1 id="zoom.queryconversions">
3037 <title>Query conversions</title>
3039 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
3040 ZOOM_connection conn);
3042 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
3044 int *ccl_error, const char **error_string,
3048 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
3049 client-side, into RPN which may be passed to the server.
3050 This is useful for server's that don't themselves
3051 support CQL, for which <function>ZOOM_query_cql</function> is useless.
3052 `conn' is used only as a place to stash diagnostics if compilation
3053 fails; if this information is not needed, a null pointer may be used.
3054 The CQL conversion is driven by option <literal>cqlfile</literal> from
3055 connection conn. This specifies a conversion file (eg pqf.properties)
3056 which <emphasis>must</emphasis> be present.
3059 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
3060 client-side, into RPN which may be passed to the server.
3061 The conversion is driven by the specification given by
3062 <literal>config</literal>. Upon completion 0 is returned on success; -1
3063 is returned on on failure. Om failure <literal>error_string</literal> and
3064 <literal>error_pos</literal> holds error message and position of
3065 first error in original CCL string.
3068 <sect1 id="zoom.events"><title>Events</title>
3070 If you're developing non-blocking applications, you have to deal
3074 int ZOOM_event(int no, ZOOM_connection *cs);
3077 The <function>ZOOM_event</function> executes pending events for
3078 a number of connections. Supply the number of connections in
3079 <literal>no</literal> and an array of connections in
3080 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
3081 A pending event could be a sending a search, receiving a response,
3083 When an event has occurred for one of the connections, this function
3084 returns a positive integer <literal>n</literal> denoting that an event
3085 occurred for connection <literal>cs[n-1]</literal>.
3086 When no events are pending for the connections, a value of zero is
3088 To ensure that all outstanding requests are performed call this function
3089 repeatedly until zero is returned.
3092 If <function>ZOOM_event</function> returns and returns non-zero, the
3093 last event that occurred can be expected.
3096 int ZOOM_connection_last_event(ZOOM_connection cs);
3099 <function>ZOOM_connection_last_event</function> returns an event type
3100 (integer) for the last event.
3103 <table frame="top" id="zoom.event.ids">
3104 <title>ZOOM Event IDs</title>
3106 <colspec colwidth="4*" colname="name"></colspec>
3107 <colspec colwidth="7*" colname="description"></colspec>
3110 <entry>Event</entry>
3111 <entry>Description</entry>
3116 <entry>ZOOM_EVENT_NONE</entry>
3117 <entry>No event has occurred</entry>
3120 <entry>ZOOM_EVENT_CONNECT</entry>
3121 <entry>TCP/IP connect has initiated</entry>
3124 <entry>ZOOM_EVENT_SEND_DATA</entry>
3125 <entry>Data has been transmitted (sending)</entry>
3128 <entry>ZOOM_EVENT_RECV_DATA</entry>
3129 <entry>Data has been received)</entry>
3132 <entry>ZOOM_EVENT_TIMEOUT</entry>
3133 <entry>Timeout</entry>
3136 <entry>ZOOM_EVENT_UNKNOWN</entry>
3137 <entry>Unknown event</entry>
3140 <entry>ZOOM_EVENT_SEND_APDU</entry>
3141 <entry>An APDU has been transmitted (sending)</entry>
3144 <entry>ZOOM_EVENT_RECV_APDU</entry>
3145 <entry>An APDU has been received</entry>
3148 <entry>ZOOM_EVENT_RECV_RECORD</entry>
3149 <entry>A result-set record has been received</entry>
3152 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
3153 <entry>A search result been received</entry>
3160 <chapter id="server">
3161 <title>Generic server</title>
3162 <sect1 id="server.introduction"><title>Introduction</title>
3164 If you aren't into documentation, a good way to learn how the
3165 back end interface works is to look at the <filename>backend.h</filename>
3166 file. Then, look at the small dummy-server in
3167 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
3168 file also makes a good reference, once you've chewed your way through
3169 the prose of this file.
3172 If you have a database system that you would like to make available by
3173 means of Z39.50 or SRU, &yaz; basically offers your two options. You
3174 can use the APIs provided by the &asn;, &odr;, and &comstack;
3176 create and decode PDUs, and exchange them with a client.
3177 Using this low-level interface gives you access to all fields and
3178 options of the protocol, and you can construct your server as close
3179 to your existing database as you like.
3180 It is also a fairly involved process, requiring
3181 you to set up an event-handling mechanism, protocol state machine,
3182 etc. To simplify server implementation, we have implemented a compact
3183 and simple, but reasonably full-functioned server-frontend that will
3184 handle most of the protocol mechanics, while leaving you to
3185 concentrate on your database interface.
3189 The backend interface was designed in anticipation of a specific
3190 integration task, while still attempting to achieve some degree of
3191 generality. We realize fully that there are points where the
3192 interface can be improved significantly. If you have specific
3193 functions or parameters that you think could be useful, send us a
3194 mail (or better, sign on to the mailing list referred to in the
3195 top-level README file). We will try to fit good suggestions into future
3196 releases, to the extent that it can be done without requiring
3197 too many structural changes in existing applications.
3202 The &yaz; server does not support XCQL.
3206 <sect1 id="server.frontend">
3207 <title>The Database Frontend</title>
3209 We refer to this software as a generic database frontend. Your
3210 database system is the <emphasis>backend database</emphasis>, and the
3211 interface between the two is called the <emphasis>backend API</emphasis>.
3212 The backend API consists of a small number of function handlers and
3213 structure definitions. You are required to provide the
3214 <function>main()</function> routine for the server (which can be
3215 quite simple), as well as a set of handlers to match each of the
3217 The interface functions that you write can use any mechanism you like
3218 to communicate with your database system: You might link the whole
3219 thing together with your database application and access it by
3220 function calls; you might use IPC to talk to a database server
3221 somewhere; or you might link with third-party software that handles
3222 the communication for you (like a commercial database client library).
3223 At any rate, the handlers will perform the tasks of:
3236 Scanning the database index (optional - if you wish to implement SCAN).
3239 Extended Services (optional).
3242 Result-Set Delete (optional).
3245 Result-Set Sort (optional).
3248 Return Explain for SRU (optional).
3252 (more functions will be added in time to support as much of
3253 Z39.50-1995 as possible).
3256 <sect1 id="server.backend">
3257 <title>The Backend API</title>
3259 The header file that you need to use the interface are in the
3260 <filename>include/yaz</filename> directory. It's called
3261 <filename>backend.h</filename>. It will include other files from
3262 the <filename>include/yaz</filename> directory, so you'll
3263 probably want to use the -I option of your compiler to tell it
3264 where to find the files. When you run
3265 <literal>make</literal> in the top-level &yaz; directory,
3266 everything you need to create your server is to link with the
3267 <filename>lib/libyaz.la</filename> library.
3270 <sect1 id="server.main">
3271 <title>Your main() Routine</title>
3273 As mentioned, your <function>main()</function> routine can be quite brief.
3274 If you want to initialize global parameters, or read global configuration
3275 tables, this is the place to do it. At the end of the routine, you should
3279 int statserv_main(int argc, char **argv,
3280 bend_initresult *(*bend_init)(bend_initrequest *r),
3281 void (*bend_close)(void *handle));
3284 The third and fourth arguments are pointers to handlers. Handler
3285 <function>bend_init</function> is called whenever the server receives
3286 an Initialize Request, so it serves as a Z39.50 session initializer. The
3287 <function>bend_close</function> handler is called when the session is
3291 <function>statserv_main</function> will establish listening sockets
3292 according to the parameters given. When connection requests are received,
3293 the event handler will typically <function>fork()</function> and
3294 create a sub-process to handle a new connection.
3295 Alternatively the server may be setup to create threads for each
3297 If you do use global variables and forking, you should be aware, then,
3298 that these cannot be shared between associations, unless you explicitly
3299 disable forking by command line parameters.
3302 The server provides a mechanism for controlling some of its behavior
3303 without using command-line options. The function
3306 statserv_options_block *statserv_getcontrol(void);
3309 will return a pointer to a <literal>struct statserv_options_block</literal>
3310 describing the current default settings of the server. The structure
3311 contains these elements:
3314 <term><literal>int dynamic</literal></term>
3316 A boolean value, which determines whether the server
3317 will fork on each incoming request (TRUE), or not (FALSE). Default is
3318 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3323 <term><literal>int threads</literal></term>
3325 A boolean value, which determines whether the server
3326 will create a thread on each incoming request (TRUE), or not (FALSE).
3327 Default is FALSE. This flag is only read by UNIX-based servers
3328 that offer POSIX Threads support.
3329 WIN32-based servers always operate in threaded mode.
3333 <term><literal>int inetd</literal></term>
3335 A boolean value, which determines whether the server
3336 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3340 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3341 <listitem><para>File for diagnostic output ("": stderr).
3345 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3347 Name of file for logging incoming and outgoing APDUs
3348 ("": don't log APDUs, "-":
3349 <literal>stderr</literal>).
3353 <term><literal>char default_listen[1024]</literal></term>
3354 <listitem><para>Same form as the command-line specification of
3355 listener address. "": no default listener address.
3356 Default is to listen at "tcp:@:9999". You can only
3357 specify one default listener address in this fashion.
3361 <term><literal>enum oid_proto default_proto;</literal></term>
3362 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3363 <literal>PROTO_SR</literal>.
3364 Default is <literal>PROTO_Z39_50</literal>.
3368 <term><literal>int idle_timeout;</literal></term>
3369 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3370 no (infinite) timeout. Default is 15 minutes.
3374 <term><literal>int maxrecordsize;</literal></term>
3375 <listitem><para>Maximum permissible record (message) size. Default
3376 is 64 MB. This amount of memory will only be allocated if a
3377 client requests a very large amount of records in one operation
3379 Set it to a lower number if you are worried about resource
3380 consumption on your host system.
3384 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3385 <listitem><para>Passed to the backend when a new connection is received.
3389 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3390 <listitem><para>Set user id to the user specified, after binding
3391 the listener addresses.
3396 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3398 <listitem><para>Pointer to function which is called after the
3399 command line options have been parsed - but before the server
3401 For forked UNIX servers this handler is called in the mother
3402 process; for threaded servers this handler is called in the
3404 The default value of this pointer is NULL in which case it
3405 isn't invoked by the frontend server.
3406 When the server operates as an NT service this handler is called
3407 whenever the service is started.
3412 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3414 <listitem><para>Pointer to function which is called whenever the server
3415 has stopped listening for incoming connections. This function pointer
3416 has a default value of NULL in which case it isn't called.
3417 When the server operates as an NT service this handler is called
3418 whenever the service is stopped.
3422 <term><literal>void *handle</literal></term>
3423 <listitem><para>User defined pointer (default value NULL).
3424 This is a per-server handle that can be used to specify "user-data".
3425 Do not confuse this with the session-handle as returned by bend_init.
3431 The pointer returned by <literal>statserv_getcontrol</literal> points to
3432 a static area. You are allowed to change the contents of the structure,
3433 but the changes will not take effect before you call
3436 void statserv_setcontrol(statserv_options_block *block);
3440 that you should generally update this structure before calling
3441 <function>statserv_main()</function>.
3445 <sect1 id="server.backendfunctions">
3446 <title>The Backend Functions</title>
3448 For each service of the protocol, the backend interface declares one or
3449 two functions. You are required to provide implementations of the
3450 functions representing the services that you wish to implement.
3452 <sect2 id="server.init">
3455 bend_initresult (*bend_init)(bend_initrequest *r);
3458 This handler is called once for each new connection request, after
3459 a new process/thread has been created, and an Initialize Request has
3460 been received from the client. The pointer to the
3461 <function>bend_init</function> handler is passed in the call to
3462 <function>statserv_start</function>.
3465 This handler is also called when operating in SRU mode - when
3466 a connection has been made (even though SRU does not offer
3470 Unlike previous versions of YAZ, the <function>bend_init</function> also
3471 serves as a handler that defines the Z39.50 services that the backend
3472 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3473 including search - and fetch must be specified here in this handler.
3476 The request - and result structures are defined as
3479 typedef struct bend_initrequest
3481 /** \brief user/name/password to be read */
3482 Z_IdAuthentication *auth;
3483 /** \brief encoding stream (for results) */
3485 /** \brief printing stream */
3487 /** \brief decoding stream (use stream for results) */
3489 /** \brief reference ID */
3490 Z_ReferenceId *referenceId;
3491 /** \brief peer address of client */
3494 /** \brief character set and language negotiation
3496 see include/yaz/z-charneg.h
3498 Z_CharSetandLanguageNegotiation *charneg_request;
3500 /** \brief character negotiation response */
3501 Z_External *charneg_response;
3503 /** \brief character set (encoding) for query terms
3505 This is NULL by default. It should be set to the native character
3506 set that the backend assumes for query terms */
3507 char *query_charset;
3509 /** \brief whehter query_charset also applies to recors
3511 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3512 character set as queries. If in doubt, use 0 (No).
3514 int records_in_same_charset;
3516 char *implementation_id;
3517 char *implementation_name;
3518 char *implementation_version;
3520 /** \brief Z39.50 sort handler */
3521 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3522 /** \brief SRU/Z39.50 search handler */
3523 int (*bend_search)(void *handle, bend_search_rr *rr);
3524 /** \brief SRU/Z39.50 fetch handler */
3525 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3526 /** \brief SRU/Z39.50 present handler */
3527 int (*bend_present)(void *handle, bend_present_rr *rr);
3528 /** \brief Z39.50 extended services handler */
3529 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3530 /** \brief Z39.50 delete result set handler */
3531 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3532 /** \brief Z39.50 scan handler */
3533 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3534 /** \brief Z39.50 segment facility handler */
3535 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3536 /** \brief SRU explain handler */
3537 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3538 /** \brief SRU scan handler */
3539 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3540 /** \brief SRU record update handler */
3541 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3543 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3544 int named_result_sets;
3547 typedef struct bend_initresult
3549 int errcode; /* 0==OK */
3550 char *errstring; /* system error string or NULL */
3551 void *handle; /* private handle to the backend module */
3555 In general, the server frontend expects that the
3556 <literal>bend_*result</literal> pointer that you return is valid at
3557 least until the next call to a <literal>bend_* function</literal>.
3558 This applies to all of the functions described herein. The parameter
3559 structure passed to you in the call belongs to the server frontend, and
3560 you should not make assumptions about its contents after the current
3561 function call has completed. In other words, if you want to retain any
3562 of the contents of a request structure, you should copy them.
3565 The <literal>errcode</literal> should be zero if the initialization of
3566 the backend went well. Any other value will be interpreted as an error.
3567 The <literal>errstring</literal> isn't used in the current version, but
3568 one option would be to stick it in the initResponse as a VisibleString.
3569 The <literal>handle</literal> is the most important parameter. It should
3570 be set to some value that uniquely identifies the current session to
3571 the backend implementation. It is used by the frontend server in any
3572 future calls to a backend function.
3573 The typical use is to set it to point to a dynamically allocated state
3574 structure that is private to your backend module.
3577 The <literal>auth</literal> member holds the authentication information
3578 part of the Z39.50 Initialize Request. Interpret this if your serves
3579 requires authentication.
3582 The members <literal>peer_name</literal>,
3583 <literal>implementation_id</literal>,
3584 <literal>implementation_name</literal> and
3585 <literal>implementation_version</literal> holds
3586 DNS of client, ID of implementor, name
3587 of client (Z39.50) implementation - and version.
3590 The <literal>bend_</literal> - members are set to NULL when
3591 <function>bend_init</function> is called. Modify the pointers by
3592 setting them to point to backend functions.
3595 <sect2 id="server.search.retrieve">
3596 <title>Search and Retrieve</title>
3598 We now describe the handlers that are required to support search -
3599 and retrieve. You must support two functions - one for search - and one
3600 for fetch (retrieval of one record). If desirable you can provide a
3601 third handler which is called when a present request is received which
3602 allows you to optimize retrieval of multiple-records.
3605 int (*bend_search) (void *handle, bend_search_rr *rr);
3608 char *setname; /* name to give to this set */
3609 int replace_set; /* replace set, if it already exists */
3610 int num_bases; /* number of databases in list */
3611 char **basenames; /* databases to search */
3612 Z_ReferenceId *referenceId;/* reference ID */
3613 Z_Query *query; /* query structure */
3614 ODR stream; /* encode stream */
3615 ODR decode; /* decode stream */
3616 ODR print; /* print stream */
3618 bend_request request;
3619 bend_association association;
3621 int hits; /* number of hits */
3622 int errcode; /* 0==OK */
3623 char *errstring; /* system error string or NULL */
3624 Z_OtherInformation *search_info; /* additional search info */
3625 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3626 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3627 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3628 int estimated_hit_count; /* if hit count is estimated */
3629 int partial_resultset; /* if result set is partial */
3633 The <function>bend_search</function> handler is a fairly close
3634 approximation of a protocol Z39.50 Search Request - and Response PDUs
3635 The <literal>setname</literal> is the resultSetName from the protocol.
3636 You are required to establish a mapping between the set name and whatever
3637 your backend database likes to use.
3638 Similarly, the <literal>replace_set</literal> is a boolean value
3639 corresponding to the resultSetIndicator field in the protocol.
3640 <literal>num_bases/basenames</literal> is a length of/array of character
3641 pointers to the database names provided by the client.
3642 The <literal>query</literal> is the full query structure as defined in
3643 the protocol ASN.1 specification.
3644 It can be either of the possible query types, and it's up to you to
3645 determine if you can handle the provided query type.
3646 Rather than reproduce the C interface here, we'll refer you to the
3647 structure definitions in the file
3648 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3649 attributeSetId OID of the RPN query, you can either match it against
3650 your own internal tables, or you can use the <link linkend="tools.oid">
3654 The structure contains a number of hits, and an
3655 <literal>errcode/errstring</literal> pair. If an error occurs
3656 during the search, or if you're unhappy with the request, you should
3657 set the errcode to a value from the BIB-1 diagnostic set. The value
3658 will then be returned to the user in a nonsurrogate diagnostic record
3659 in the response. The <literal>errstring</literal>, if provided, will
3660 go in the addinfo field. Look at the protocol definition for the
3661 defined error codes, and the suggested uses of the addinfo field.
3664 The <function>bend_search</function> handler is also called when
3665 the frontend server receives a SRU SearchRetrieveRequest.
3666 For SRU, a CQL query is usually provided by the client.
3667 The CQL query is available as part of <literal>Z_Query</literal>
3668 structure (note that CQL is now part of Z39.50 via an external).
3669 To support CQL in existing implementations that only do Type-1,
3670 we refer to the CQL-to-PQF tool described
3671 <link linkend="cql.to.pqf">here</link>.
3674 To maintain backwards compatibility, the frontend server
3675 of yaz always assume that error codes are BIB-1 diagnostics.
3676 For SRU operation, a Bib-1 diagnostic code is mapped to
3680 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3682 typedef struct bend_fetch_rr {
3683 char *setname; /* set name */
3684 int number; /* record number */
3685 Z_ReferenceId *referenceId;/* reference ID */
3686 Odr_oid *request_format; /* format, transfer syntax (OID) */
3687 Z_RecordComposition *comp; /* Formatting instructions */
3688 ODR stream; /* encoding stream - memory source if req */
3689 ODR print; /* printing stream */
3691 char *basename; /* name of database that provided record */
3692 int len; /* length of record or -1 if structured */
3693 char *record; /* record */
3694 int last_in_set; /* is it? */
3695 Odr_oid *output_format; /* response format/syntax (OID) */
3696 int errcode; /* 0==success */
3697 char *errstring; /* system error string or NULL */
3698 int surrogate_flag; /* surrogate diagnostic */
3699 char *schema; /* string record schema input/output */
3703 The frontend server calls the <function>bend_fetch</function> handler
3704 when it needs database records to fulfill a Z39.50 Search Request, a
3705 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3706 The <literal>setname</literal> is simply the name of the result set
3707 that holds the reference to the desired record.
3708 The <literal>number</literal> is the offset into the set (with 1
3709 being the first record in the set). The <literal>format</literal> field
3710 is the record format requested by the client (See
3711 <xref linkend="tools.oid"/>).
3712 A value of NULL for <literal>format</literal> indicates that the
3713 client did not request a specific format.
3714 The <literal>stream</literal> argument is an &odr; stream which
3715 should be used for allocating space for structured data records.
3716 The stream will be reset when all records have been assembled, and
3717 the response package has been transmitted.
3718 For unstructured data, the backend is responsible for maintaining a
3719 static or dynamic buffer for the record between calls.
3722 If a SRU SearchRetrieveRequest is received by the frontend server,
3723 the <literal>referenceId</literal> is NULL and the
3724 <literal>format</literal> (transfer syntax) is the OID for XML.
3725 The schema for SRU is stored in both the
3726 <literal>Z_RecordComposition</literal>
3727 structure and <literal>schema</literal> (simple string).
3730 In the structure, the <literal>basename</literal> is the name of the
3731 database that holds the
3732 record. <literal>len</literal> is the length of the record returned, in
3733 bytes, and <literal>record</literal> is a pointer to the record.
3734 <literal>last_in_set</literal> should be nonzero only if the record
3735 returned is the last one in the given result set.
3736 <literal>errcode</literal> and <literal>errstring</literal>, if
3737 given, will be interpreted as a global error pertaining to the
3738 set, and will be returned in a non-surrogate-diagnostic.
3739 If you wish to return the error as a surrogate-diagnostic
3740 (local error) you can do this by setting
3741 <literal>surrogate_flag</literal> to 1 also.
3744 If the <literal>len</literal> field has the value -1, then
3745 <literal>record</literal> is assumed to point to a constructed data
3746 type. The <literal>format</literal> field will be used to determine
3747 which encoder should be used to serialize the data.
3751 If your backend generates structured records, it should use
3752 <function>odr_malloc()</function> on the provided stream for allocating
3753 data: This allows the frontend server to keep track of the record sizes.
3757 The <literal>format</literal> field is mapped to an object identifier
3758 in the direct reference of the resulting EXTERNAL representation
3763 The current version of &yaz; only supports the direct reference mode.
3767 int (*bend_present) (void *handle, bend_present_rr *rr);
3770 char *setname; /* set name */
3772 int number; /* record number */
3773 Odr_oid *format; /* format, transfer syntax (OID) */
3774 Z_ReferenceId *referenceId;/* reference ID */
3775 Z_RecordComposition *comp; /* Formatting instructions */
3776 ODR stream; /* encoding stream - memory source if required */
3777 ODR print; /* printing stream */
3778 bend_request request;
3779 bend_association association;
3781 int hits; /* number of hits */
3782 int errcode; /* 0==OK */
3783 char *errstring; /* system error string or NULL */
3787 The <function>bend_present</function> handler is called when
3788 the server receives a Z39.50 Present Request.
3789 The <literal>setname</literal>,
3790 <literal>start</literal> and <literal>number</literal> is the
3791 name of the result set - start position - and number of records to
3792 be retrieved respectively. <literal>format</literal> and
3793 <literal>comp</literal> is the preferred transfer syntax and element
3794 specifications of the present request.
3797 Note that this is handler serves as a supplement for
3798 <function>bend_fetch</function> and need not to be defined in order to
3799 support search - and retrieve.
3802 <sect2 id="server.delete">
3803 <title>Delete</title>
3805 For back-ends that supports delete of a result set only one handler
3809 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3811 typedef struct bend_delete_rr {
3815 Z_ReferenceId *referenceId;
3816 int delete_status; /* status for the whole operation */
3817 int *statuses; /* status each set - indexed as setnames */
3824 The delete set function definition is rather primitive, mostly because
3825 we have had no practical need for it as of yet. If someone wants
3826 to provide a full delete service, we'd be happy to add the
3827 extra parameters that are required. Are there clients out there
3828 that will actually delete sets they no longer need?
3832 <sect2 id="server.scan">
3835 For servers that wish to offer the scan service one handler
3839 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3842 BEND_SCAN_SUCCESS, /* ok */
3843 BEND_SCAN_PARTIAL /* not all entries could be found */
3846 typedef struct bend_scan_rr {
3847 int num_bases; /* number of elements in databaselist */
3848 char **basenames; /* databases to search */
3849 Odr_oid *attributeset;
3850 Z_ReferenceId *referenceId; /* reference ID */
3851 Z_AttributesPlusTerm *term;
3852 ODR stream; /* encoding stream - memory source if required */
3853 ODR print; /* printing stream */
3855 int *step_size; /* step size */
3856 int term_position; /* desired index of term in result list/returned */
3857 int num_entries; /* number of entries requested/returned */
3859 /* scan term entries. The called handler does not have
3860 to allocate this. Size of entries is num_entries (see above) */
3861 struct scan_entry *entries;
3862 bend_scan_status status;
3865 char *scanClause; /* CQL scan clause */
3866 char *setname; /* Scan in result set (NULL if omitted) */
3870 This backend server handles both Z39.50 scan
3871 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3872 Z39.50 Scan , it must check for a non-NULL value of
3873 <literal>scanClause</literal>.
3877 if designed today, it would be a choice using a union or similar,
3878 but that would break binary compatibility with existing servers.
3883 <sect1 id="server.invocation">
3884 <title>Application Invocation</title>
3886 The finished application has the following
3887 invocation syntax (by way of <function>statserv_main()</function>):
3895 A listener specification consists of a transport mode followed by a
3896 colon (:) followed by a listener address. The transport mode is
3897 either <literal>tcp</literal>, <literal>unix:</literal> or
3898 <literal>ssl</literal>.
3901 For TCP and SSL, an address has the form
3904 hostname | IP-number [: portnumber]
3907 The port number defaults to 210 (standard Z39.50 port).
3910 For UNIX, the address is the filename of socket.
3913 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3914 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3915 IPV4 binding as well (bindv6only=0),
3916 The special hostname <literal>@4</literal> binds to
3917 <literal>INADDR_ANY</literal> (IPV4 only listener).
3918 The special hostname <literal>@6</literal> binds to
3919 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3921 <example id="server.example.running.unix">
3922 <title>Running the GFS on Unix</title>
3924 Assuming the server application <replaceable>appname</replaceable> is
3925 started as root, the following will make it listen on port 210.
3926 The server will change identity to <literal>nobody</literal>
3927 and write its log to <filename>/var/log/app.log</filename>.
3929 application -l /var/log/app.log -u nobody tcp:@:210
3933 The server will accept Z39.50 requests and offer SRU service on port 210.
3936 <example id="server.example.apache.sru">
3937 <title>Setting up Apache as SRU Frontend</title>
3939 If you use <ulink url="&url.apache;">Apache</ulink>
3940 as your public web server and want to offer HTTP port 80
3941 access to the YAZ server on 210, you can use the
3942 <ulink url="&url.apache.directive.proxypass;">
3943 <literal>ProxyPass</literal></ulink>
3945 If you have virtual host
3946 <literal>srw.mydomain</literal> you can use the following directives
3947 in Apache's httpd.conf:
3950 ErrorLog /home/srw/logs/error_log
3951 TransferLog /home/srw/logs/access_log
3952 ProxyPass / http://srw.mydomain:210/
3957 The above for the Apache 1.3 series.
3960 <example id="server.example.local.access">
3961 <title>Running a server with local access only</title>
3963 Servers that is only being accessed from the local host should listen
3964 on UNIX file socket rather than a Internet socket. To listen on
3965 <filename>/tmp/mysocket</filename> start the server as follows:
3967 application unix:/tmp/mysocket
3972 <sect1 id="server.vhosts">
3973 <title>GFS Configuration and Virtual Hosts</title>
3978 <title>The Z39.50 ASN.1 Module</title>
3979 <sect1 id="asn.introduction">
3980 <title>Introduction</title>
3982 The &asn; module provides you with a set of C struct definitions for the
3983 various PDUs of the Z39.50 protocol, as well as for the complex types
3984 appearing within the PDUs. For the primitive data types, the C
3985 representation often takes the form of an ordinary C language type,
3986 such as <literal>Odr_int</literal> which is equivalent to an integral
3987 C integer. For ASN.1 constructs that have no direct
3988 representation in C, such as general octet strings and bit strings,
3989 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3990 provides auxiliary definitions.
3993 The &asn; module is located in sub directory <filename>z39.50</filename>.
3994 There you'll find C files that implements encoders and decoders for the
3995 Z39.50 types. You'll also find the protocol definitions:
3996 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
4000 <sect1 id="asn.preparing">
4001 <title>Preparing PDUs</title>
4003 A structure representing a complex ASN.1 type doesn't in itself contain the
4004 members of that type. Instead, the structure contains
4005 <emphasis>pointers</emphasis> to the members of the type.
4006 This is necessary, in part, to allow a mechanism for specifying which
4007 of the optional structure (SEQUENCE) members are present, and which
4008 are not. It follows that you will need to somehow provide space for
4009 the individual members of the structure, and set the pointers to
4010 refer to the members.
4013 The conversion routines don't care how you allocate and maintain your
4014 C structures - they just follow the pointers that you provide.
4015 Depending on the complexity of your application, and your personal
4016 taste, there are at least three different approaches that you may take
4017 when you allocate the structures.
4020 You can use static or automatic local variables in the function that
4021 prepares the PDU. This is a simple approach, and it provides the most
4022 efficient form of memory management. While it works well for flat
4023 PDUs like the InitReqest, it will generally not be sufficient for say,
4024 the generation of an arbitrarily complex RPN query structure.
4027 You can individually create the structure and its members using the
4028 <function>malloc(2)</function> function. If you want to ensure that
4029 the data is freed when it is no longer needed, you will have to
4030 define a function that individually releases each member of a
4031 structure before freeing the structure itself.
4034 You can use the <function>odr_malloc()</function> function (see
4035 <xref linkend="odr.use"/> for details). When you use
4036 <function>odr_malloc()</function>, you can release all of the
4037 allocated data in a single operation, independent of any pointers and
4038 relations between the data. <function>odr_malloc()</function> is based on a
4039 "nibble-memory"
4040 scheme, in which large portions of memory are allocated, and then
4041 gradually handed out with each call to <function>odr_malloc()</function>.
4042 The next time you call <function>odr_reset()</function>, all of the
4043 memory allocated since the last call is recycled for future use (actually,
4044 it is placed on a free-list).
4047 You can combine all of the methods described here. This will often be
4048 the most practical approach. For instance, you might use
4049 <function>odr_malloc()</function> to allocate an entire structure and
4050 some of its elements, while you leave other elements pointing to global
4051 or per-session default variables.
4054 The &asn; module provides an important aid in creating new PDUs. For
4055 each of the PDU types (say, <function>Z_InitRequest</function>), a
4056 function is provided that allocates and initializes an instance of
4057 that PDU type for you. In the case of the InitRequest, the function is
4058 simply named <function>zget_InitRequest()</function>, and it sets up
4059 reasonable default value for all of the mandatory members. The optional
4060 members are generally initialized to null pointers. This last aspect
4061 is very important: it ensures that if the PDU definitions are
4062 extended after you finish your implementation (to accommodate
4063 new versions of the protocol, say), you won't get into trouble with
4064 uninitialized pointers in your structures. The functions use
4065 <function>odr_malloc()</function> to
4066 allocate the PDUs and its members, so you can free everything again with a
4067 single call to <function>odr_reset()</function>. We strongly recommend
4068 that you use the <literal>zget_*</literal>
4069 functions whenever you are preparing a PDU (in a C++ API, the
4070 <literal>zget_</literal>
4071 functions would probably be promoted to constructors for the
4075 The prototype for the individual PDU types generally look like this:
4078 Z_<type> *zget_<type>(ODR o);
4084 Z_InitRequest *zget_InitRequest(ODR o);
4087 The &odr; handle should generally be your encoding stream, but it
4091 As well as the individual PDU functions, a function
4092 <function>zget_APDU()</function> is provided, which allocates
4093 a top-level Z-APDU of the type requested:
4096 Z_APDU *zget_APDU(ODR o, int which);
4099 The <varname>which</varname> parameter is (of course) the discriminator
4100 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
4101 All of the interface described here is provided by the &asn; module, and
4102 you access it through the <filename>proto.h</filename> header file.
4105 <sect1 id="asn.external">
4106 <title>EXTERNAL Data</title>
4108 In order to achieve extensibility and adaptability to different
4109 application domains, the new version of the protocol defines many
4110 structures outside of the main ASN.1 specification, referencing them
4111 through ASN.1 EXTERNAL constructs. To simplify the construction and
4112 access to the externally referenced data, the &asn; module defines a
4113 specialized version of the EXTERNAL construct, called
4114 <literal>Z_External</literal>.It is defined thus:
4117 typedef struct Z_External
4119 Odr_oid *direct_reference;
4120 int *indirect_reference;
4125 Z_External_single = 0,
4127 Z_External_arbitrary,
4129 /* Specific types */
4131 Z_External_explainRecord,
4132 Z_External_resourceReport1,
4133 Z_External_resourceReport2
4141 Odr_any *single_ASN1_type;
4142 Odr_oct *octet_aligned;
4143 Odr_bitmask *arbitrary;
4145 /* Specific types */
4147 Z_ExplainRecord *explainRecord;
4148 Z_ResourceReport1 *resourceReport1;
4149 Z_ResourceReport2 *resourceReport2;
4157 When decoding, the &asn; module will attempt to determine which
4158 syntax describes the data by looking at the reference fields
4159 (currently only the direct-reference). For ASN.1 structured data, you
4160 need only consult the <literal>which</literal> field to determine the
4161 type of data. You can the access the data directly through the union.
4162 When constructing data for encoding, you set the union pointer to point
4163 to the data, and set the <literal>which</literal> field accordingly.
4164 Remember also to set the direct (or indirect) reference to the correct
4165 OID for the data type.
4166 For non-ASN.1 data such as MARC records, use the
4167 <literal>octet_aligned</literal> arm of the union.
4170 Some servers return ASN.1 structured data values (eg. database
4171 records) as BER-encoded records placed in the
4172 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
4173 The ASN-module will <emphasis>not</emphasis> automatically decode
4174 these records. To help you decode the records in the application, the
4178 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
4181 Can be used to retrieve information about the known, external data
4182 types. The function return a pointer to a static area, or NULL, if no
4183 match for the given direct reference is found. The
4184 <literal>Z_ext_typeent</literal>
4188 typedef struct Z_ext_typeent
4190 int oid[OID_SIZE]; /* the direct-reference OID. */
4191 int what; /* discriminator value for the external CHOICE */
4192 Odr_fun fun; /* decoder function */
4196 The <literal>what</literal> member contains the
4197 <literal>Z_External</literal> union discriminator value for the
4198 given type: For the SUTRS record syntax, the value would be
4199 <literal>Z_External_sutrs</literal>.
4200 The <literal>fun</literal> member contains a pointer to the
4201 function which encodes/decodes the given type. Again, for the SUTRS
4202 record syntax, the value of <literal>fun</literal> would be
4203 <literal>z_SUTRS</literal> (a function pointer).
4206 If you receive an EXTERNAL which contains an octet-string value that
4207 you suspect of being an ASN.1-structured data value, you can use
4208 <literal>z_ext_gettypebyref</literal> to look for the provided
4210 If the return value is different from NULL, you can use the provided
4211 function to decode the BER string (see <xref linkend="odr.use"/>
4215 If you want to <emphasis>send</emphasis> EXTERNALs containing
4216 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4217 is possible too. However, on the encoding phase, it requires a somewhat
4218 involved juggling around of the various buffers involved.
4221 If you need to add new, externally defined data types, you must update
4222 the struct above, in the source file <filename>prt-ext.h</filename>, as
4223 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4224 When changing the latter, remember to update both the
4225 <literal>arm</literal> arrary and the list
4226 <literal>type_table</literal>, which drives the CHOICE biasing that
4227 is necessary to tell the different, structured types apart
4232 Eventually, the EXTERNAL processing will most likely
4233 automatically insert the correct OIDs or indirect-refs. First,
4234 however, we need to determine how application-context management
4235 (specifically the presentation-context-list) should fit into the
4240 <sect1 id="asn.pdu">
4241 <title>PDU Contents Table</title>
4243 We include, for reference, a listing of the fields of each top-level
4244 PDU, as well as their default settings.
4246 <table frame="top" id="asn.default.initialize.request">
4247 <title>Default settings for PDU Initialize Request</title>
4249 <colspec colwidth="7*" colname="field"></colspec>
4250 <colspec colwidth="5*" colname="type"></colspec>
4251 <colspec colwidth="7*" colname="value"></colspec>
4254 <entry>Field</entry>
4256 <entry>Default Value</entry>
4261 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4264 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4267 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4270 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4273 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4276 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4279 implementationId</entry><entry>char*</entry><entry>"81"
4282 implementationName</entry><entry>char*</entry><entry>"YAZ"
4285 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4288 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4291 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4296 <table frame="top" id="asn.default.initialize.response">
4297 <title>Default settings for PDU Initialize Response</title>
4299 <colspec colwidth="7*" colname="field"></colspec>
4300 <colspec colwidth="5*" colname="type"></colspec>
4301 <colspec colwidth="7*" colname="value"></colspec>
4304 <entry>Field</entry>
4306 <entry>Default Value</entry>
4311 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4314 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4317 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4320 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4323 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4326 result</entry><entry>Odr_bool</entry><entry>TRUE
4329 implementationId</entry><entry>char*</entry><entry>"id)"
4332 implementationName</entry><entry>char*</entry><entry>"YAZ"
4335 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4338 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4341 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4346 <table frame="top" id="asn.default.search.request">
4347 <title>Default settings for PDU Search Request</title>
4349 <colspec colwidth="7*" colname="field"></colspec>
4350 <colspec colwidth="5*" colname="type"></colspec>
4351 <colspec colwidth="7*" colname="value"></colspec>
4354 <entry>Field</entry>
4356 <entry>Default Value</entry>
4361 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4364 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4367 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4370 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4373 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4376 resultSetName</entry><entry>char *</entry><entry>"default"
4379 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4382 databaseNames</entry><entry>char **</entry><entry>NULL
4385 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4389 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4393 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4396 query</entry><entry>Z_Query</entry><entry>NULL
4399 additionalSearchInfo</entry><entry>Z_OtherInformation
4403 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4408 <table frame="top" id="asn.default.search.response">
4409 <title>Default settings for PDU Search Response</title>
4411 <colspec colwidth="7*" colname="field"></colspec>
4412 <colspec colwidth="5*" colname="type"></colspec>
4413 <colspec colwidth="7*" colname="value"></colspec>
4416 <entry>Field</entry>
4418 <entry>Default Value</entry>
4423 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4426 resultCount</entry><entry>Odr_int</entry><entry>0
4429 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4432 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4435 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4438 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4441 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4444 records</entry><entry>Z_Records</entry><entry>NULL
4447 additionalSearchInfo</entry>
4448 <entry>Z_OtherInformation</entry><entry>NULL
4451 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4456 <table frame="top" id="asn.default.present.request">
4457 <title>Default settings for PDU Present Request</title>
4459 <colspec colwidth="7*" colname="field"></colspec>
4460 <colspec colwidth="5*" colname="type"></colspec>
4461 <colspec colwidth="7*" colname="value"></colspec>
4464 <entry>Field</entry>
4466 <entry>Default Value</entry>
4471 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4474 resultSetId</entry><entry>char*</entry><entry>"default"
4477 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4480 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4483 num_ranges</entry><entry>Odr_int</entry><entry>0
4486 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4489 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4492 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4495 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4498 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4501 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4504 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4509 <table frame="top" id="asn.default.present.response">
4510 <title>Default settings for PDU Present Response</title>
4512 <colspec colwidth="7*" colname="field"></colspec>
4513 <colspec colwidth="5*" colname="type"></colspec>
4514 <colspec colwidth="7*" colname="value"></colspec>
4517 <entry>Field</entry>
4519 <entry>Default Value</entry>
4524 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4527 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4530 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4533 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4536 records</entry><entry>Z_Records</entry><entry>NULL
4539 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4544 <table frame="top" id="asn.default.delete.result.set.request">
4545 <title>Default settings for Delete Result Set Request</title>
4547 <colspec colwidth="7*" colname="field"></colspec>
4548 <colspec colwidth="5*" colname="type"></colspec>
4549 <colspec colwidth="7*" colname="value"></colspec>
4552 <entry>Field</entry>
4554 <entry>Default Value</entry>
4558 <row><entry>referenceId
4559 </entry><entry>Z_ReferenceId</entry><entry>NULL
4562 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4565 num_ids</entry><entry>Odr_int</entry><entry>0
4568 resultSetList</entry><entry>char**</entry><entry>NULL
4571 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4576 <table frame="top" id="asn.default.delete.result.set.response">
4577 <title>Default settings for Delete Result Set Response</title>
4579 <colspec colwidth="7*" colname="field"></colspec>
4580 <colspec colwidth="5*" colname="type"></colspec>
4581 <colspec colwidth="7*" colname="value"></colspec>
4584 <entry>Field</entry>
4586 <entry>Default Value</entry>
4591 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4594 deleteOperationStatus</entry><entry>Odr_int</entry>
4595 <entry>Z_DeleteStatus_success</entry></row>
4597 num_statuses</entry><entry>Odr_int</entry><entry>0
4600 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4603 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4606 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4609 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4612 deleteMessage</entry><entry>char*</entry><entry>NULL
4615 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4620 <table frame="top" id="asn.default.scan.request">
4621 <title>Default settings for Scan Request</title>
4623 <colspec colwidth="7*" colname="field"></colspec>
4624 <colspec colwidth="5*" colname="type"></colspec>
4625 <colspec colwidth="7*" colname="value"></colspec>
4628 <entry>Field</entry>
4630 <entry>Default Value</entry>
4635 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4638 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4641 databaseNames</entry><entry>char**</entry><entry>NULL
4644 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4647 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4648 </entry><entry>NULL</entry></row>
4650 stepSize</entry><entry>Odr_int</entry><entry>NULL
4653 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4656 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4659 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4664 <table frame="top" id="asn.default.scan.response">
4665 <title>Default settings for Scan Response</title>
4667 <colspec colwidth="7*" colname="field"></colspec>
4668 <colspec colwidth="5*" colname="type"></colspec>
4669 <colspec colwidth="7*" colname="value"></colspec>
4672 <entry>Field</entry>
4674 <entry>Default Value</entry>
4679 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4682 stepSize</entry><entry>Odr_int</entry><entry>NULL
4685 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4688 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4691 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4694 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4697 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4700 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4705 <table frame="top" id="asn.default.trigger.resource.control.request">
4706 <title>Default settings for Trigger Resource Control Request</title>
4708 <colspec colwidth="7*" colname="field"></colspec>
4709 <colspec colwidth="5*" colname="type"></colspec>
4710 <colspec colwidth="7*" colname="value"></colspec>
4713 <entry>Field</entry>
4715 <entry>Default Value</entry>
4720 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4723 requestedAction</entry><entry>Odr_int</entry><entry>
4724 Z_TriggerResourceCtrl_resou..
4727 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4730 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4733 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4738 <table frame="top" id="asn.default.resource.control.request">
4739 <title>Default settings for Resource Control Request</title>
4741 <colspec colwidth="7*" colname="field"></colspec>
4742 <colspec colwidth="5*" colname="type"></colspec>
4743 <colspec colwidth="7*" colname="value"></colspec>
4746 <entry>Field</entry>
4748 <entry>Default Value</entry>
4753 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4756 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4759 resourceReport</entry><entry>Z_External</entry><entry>NULL
4762 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4765 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4768 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4771 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4776 <table frame="top" id="asn.default.resource.control.response">
4777 <title>Default settings for Resource Control Response</title>
4779 <colspec colwidth="7*" colname="field"></colspec>
4780 <colspec colwidth="5*" colname="type"></colspec>
4781 <colspec colwidth="7*" colname="value"></colspec>
4784 <entry>Field</entry>
4786 <entry>Default Value</entry>
4791 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4794 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4797 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4800 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4805 <table frame="top" id="asn.default.access.control.request">
4806 <title>Default settings for Access Control Request</title>
4808 <colspec colwidth="7*" colname="field"></colspec>
4809 <colspec colwidth="5*" colname="type"></colspec>
4810 <colspec colwidth="7*" colname="value"></colspec>
4813 <entry>Field</entry>
4815 <entry>Default Value</entry>
4820 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4823 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4826 u</entry><entry>union</entry><entry>NULL
4829 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4834 <table frame="top" id="asn.default.access.control.response">
4835 <title>Default settings for Access Control Response</title>
4837 <colspec colwidth="7*" colname="field"></colspec>
4838 <colspec colwidth="5*" colname="type"></colspec>
4839 <colspec colwidth="7*" colname="value"></colspec>
4842 <entry>Field</entry>
4844 <entry>Default Value</entry>
4849 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4852 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4855 u</entry><entry>union</entry><entry>NULL
4858 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4861 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4866 <table frame="top" id="asn.default.segment">
4867 <title>Default settings for Segment</title>
4869 <colspec colwidth="7*" colname="field"></colspec>
4870 <colspec colwidth="5*" colname="type"></colspec>
4871 <colspec colwidth="7*" colname="value"></colspec>
4874 <entry>Field</entry>
4876 <entry>Default Value</entry>
4881 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4884 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4887 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4890 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4892 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4897 <table frame="top" id="asn.default.close">
4898 <title>Default settings for Close</title>
4900 <colspec colwidth="7*" colname="field"></colspec>
4901 <colspec colwidth="5*" colname="type"></colspec>
4902 <colspec colwidth="7*" colname="value"></colspec>
4905 <entry>Field</entry>
4907 <entry>Default Value</entry>
4912 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4915 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4918 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4921 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4924 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4927 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4935 <title>SOAP and SRU</title>
4936 <sect1 id="soap.introduction">
4937 <title>Introduction</title>
4939 &yaz; uses a very simple implementation of
4940 <ulink url="&url.soap;">SOAP</ulink> that only,
4941 currenly, supports what is sufficient to offer SRU SOAP functionality.
4942 The implementation uses the
4943 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4944 libxml2 to encode and decode SOAP packages.
4947 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4948 simple C structs to represent SOAP packages as well as
4952 <sect1 id="soap.http">
4955 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4956 relatively easy to change that.
4959 The following definition of <literal>Z_GDU</literal> (Generic Data
4960 Unit) allows for both HTTP and Z39.50 in one packet.
4963 #include <yaz/zgdu.h>
4965 #define Z_GDU_Z3950 1
4966 #define Z_GDU_HTTP_Request 2
4967 #define Z_GDU_HTTP_Response 3
4972 Z_HTTP_Request *HTTP_Request;
4973 Z_HTTP_Response *HTTP_Response;
4978 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4979 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4981 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4982 is the HTTP Request and Response respectively.
4985 <sect1 id="soap.xml">
4986 <title>SOAP Packages</title>
4988 Every SOAP package in &yaz; is represented as follows:
4990 #include <yaz/soap.h>
5004 #define Z_SOAP_fault 1
5005 #define Z_SOAP_generic 2
5006 #define Z_SOAP_error 3
5010 Z_SOAP_Fault *fault;
5011 Z_SOAP_Generic *generic;
5012 Z_SOAP_Fault *soap_error;
5019 The <literal>fault</literal> and <literal>soap_error</literal>
5020 arms represent both a SOAP fault - struct
5021 <literal>Z_SOAP_Fault</literal>. Any other generic
5022 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
5025 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
5026 is the namespace for SOAP itself and reflects the SOAP
5027 version. For version 1.1 it is
5028 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
5029 for version 1.2 it is
5030 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
5033 int z_soap_codec(ODR o, Z_SOAP **pp,
5034 char **content_buf, int *content_len,
5035 Z_SOAP_Handler *handlers);
5038 The <literal>content_buf</literal> and <literal>content_len</literal>
5039 is XML buffer and length of buffer respectively.
5042 The <literal>handlers</literal> is a list of SOAP codec
5043 handlers - one handler for each service namespace. For SRU SOAP, the
5044 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
5047 When decoding, the <function>z_soap_codec</function>
5048 inspects the XML content
5049 and tries to match one of the services namespaces of the
5050 supplied handlers. If there is a match a handler function
5051 is invoked which decodes that particular SOAP package.
5052 If successful, the returned <literal>Z_SOAP</literal> package will be
5053 of type <literal>Z_SOAP_Generic</literal>.
5054 Member <literal>no</literal> is
5055 set the offset of handler that matched; <literal>ns</literal>
5056 is set to namespace of matching handler; the void pointer
5057 <literal>p</literal> is set to the C data structure assocatiated
5061 When a NULL namespace is met (member <literal>ns</literal> bwlow),
5062 that specifies end-of-list.
5065 Each handler is defined as follows:
5073 The <literal>ns</literal> is namespace of service associated with
5074 handler <literal>f</literal>. <literal>client_data</literal>
5075 is user-defined data which is passed to handler.
5078 The prototype for a SOAP service handler is:
5080 int handler(ODR o, void * ptr, void **handler_data,
5081 void *client_data, const char *ns);
5083 The <parameter>o</parameter> specifies the mode (decode/encode)
5084 as usual. The second argument, <parameter>ptr</parameter>,
5085 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
5086 and is a pointer to the <literal>Body</literal> element
5087 of the SOAP package. The <parameter>handler_data</parameter>
5088 is an opaque pointer to a C definitions associated with the
5089 SOAP service. <parameter>client_data</parameter> is the pointer
5090 which was set as part of the <literal>Z_SOAP_handler</literal>.
5091 Finally, <parameter>ns</parameter> the service namespace.
5094 <sect1 id="soap.srw">
5097 SRU SOAP is just one implementation of a SOAP handler as described
5098 in the previous section.
5099 The encoder/decoder handler for SRU is defined as
5102 #include <yaz/srw.h>
5104 int yaz_srw_codec(ODR o, void * pptr,
5105 Z_SRW_GDU **handler_data,
5106 void *client_data, const char *ns);
5108 Here, <literal>Z_SRW_GDU</literal> is either
5109 searchRetrieveRequest or a searchRetrieveResponse.
5113 The xQuery and xSortKeys are not handled yet by
5114 the SRW implementation of &yaz;. Explain is also missing.
5115 Future versions of &yaz; will include these features.
5119 The definition of searchRetrieveRequest is:
5123 #define Z_SRW_query_type_cql 1
5124 #define Z_SRW_query_type_xcql 2
5125 #define Z_SRW_query_type_pqf 3
5133 #define Z_SRW_sort_type_none 1
5134 #define Z_SRW_sort_type_sort 2
5135 #define Z_SRW_sort_type_xSort 3
5143 int *maximumRecords;
5145 char *recordPacking;
5147 } Z_SRW_searchRetrieveRequest;
5149 Please observe that data of type xsd:string is represented
5150 as a char pointer (<literal>char *</literal>). A null pointer
5151 means that the element is absent.
5152 Data of type xsd:integer is representd as a pointer to
5153 an int (<literal>int *</literal>). Again, a null pointer
5154 us used for absent elements.
5157 The SearchRetrieveResponse has the following definition.
5160 int * numberOfRecords;
5162 int * resultSetIdleTime;
5164 Z_SRW_record *records;
5167 Z_SRW_diagnostic *diagnostics;
5168 int num_diagnostics;
5169 int *nextRecordPosition;
5170 } Z_SRW_searchRetrieveResponse;
5172 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
5173 is number of returned records and diagnostics respectively and also
5174 correspond to the "size of" arrays <literal>records</literal>
5175 and <literal>diagnostics</literal>.
5178 A retrieval record is defined as follows:
5182 char *recordData_buf;
5184 int *recordPosition;
5187 The record data is defined as a buffer of some length so that
5188 data can be of any type. SRW 1.0 currenly doesn't allow for this
5189 (only XML), but future versions might do.
5192 And, a diagnostic as:
5202 <chapter id="tools">
5203 <title>Supporting Tools</title>
5205 In support of the service API - primarily the ASN module, which
5206 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5207 a collection of tools that support the development of applications.
5209 <sect1 id="tools.query">
5210 <title>Query Syntax Parsers</title>
5212 Since the type-1 (RPN) query structure has no direct, useful string
5213 representation, every origin application needs to provide some form of
5214 mapping from a local query notation or representation to a
5215 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5216 construct the query manually, perhaps using
5217 <function>odr_malloc()</function> to simplify memory management.
5218 The &yaz; distribution includes three separate, query-generating tools
5219 that may be of use to you.
5222 <title>Prefix Query Format</title>
5224 Since RPN or reverse polish notation is really just a fancy way of
5225 describing a suffix notation format (operator follows operands), it
5226 would seem that the confusion is total when we now introduce a prefix
5227 notation for RPN. The reason is one of simple laziness - it's somewhat
5228 simpler to interpret a prefix format, and this utility was designed
5229 for maximum simplicity, to provide a baseline representation for use
5230 in simple test applications and scripting environments (like Tcl). The
5231 demonstration client included with YAZ uses the PQF.
5235 The PQF have been adopted by other parties developing Z39.50
5236 software. It is often referred to as Prefix Query Notation
5241 The PQF is defined by the pquery module in the YAZ library.
5242 There are two sets of function that have similar behavior. First
5243 set operates on a PQF parser handle, second set doesn't. First set
5244 set of functions are more flexible than the second set. Second set
5245 is obsolete and is only provided to ensure backwards compatibility.
5248 First set of functions all operate on a PQF parser handle:
5251 #include <yaz/pquery.h>
5253 YAZ_PQF_Parser yaz_pqf_create(void);
5255 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5257 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5259 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5260 Odr_oid **attributeSetId, const char *qbuf);
5262 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5265 A PQF parser is created and destructed by functions
5266 <function>yaz_pqf_create</function> and
5267 <function>yaz_pqf_destroy</function> respectively.
5268 Function <function>yaz_pqf_parse</function> parses query given
5269 by string <literal>qbuf</literal>. If parsing was successful,
5270 a Z39.50 RPN Query is returned which is created using ODR stream
5271 <literal>o</literal>. If parsing failed, a NULL pointer is
5273 Function <function>yaz_pqf_scan</function> takes a scan query in
5274 <literal>qbuf</literal>. If parsing was successful, the function
5275 returns attributes plus term pointer and modifies
5276 <literal>attributeSetId</literal> to hold attribute set for the
5277 scan request - both allocated using ODR stream <literal>o</literal>.
5278 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5279 Error information for bad queries can be obtained by a call to
5280 <function>yaz_pqf_error</function> which returns an error code and
5281 modifies <literal>*msg</literal> to point to an error description,
5282 and modifies <literal>*off</literal> to the offset within last
5283 query were parsing failed.
5286 The second set of functions are declared as follows:
5289 #include <yaz/pquery.h>
5291 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5293 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5294 Odr_oid **attributeSetP, const char *qbuf);
5296 int p_query_attset(const char *arg);
5299 The function <function>p_query_rpn()</function> takes as arguments an
5300 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5301 to provide a memory source (the structure created is released on
5302 the next call to <function>odr_reset()</function> on the stream), a
5303 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5304 <token>PROTO_SR</token>), an attribute set reference, and
5305 finally a null-terminated string holding the query string.
5308 If the parse went well, <function>p_query_rpn()</function> returns a
5309 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5310 placed directly into a <literal>Z_SearchRequest</literal>.
5311 If parsing failed, due to syntax error, a NULL pointer is returned.
5314 The <literal>p_query_attset</literal> specifies which attribute set
5315 to use if the query doesn't specify one by the
5316 <literal>@attrset</literal> operator.
5317 The <literal>p_query_attset</literal> returns 0 if the argument is a
5318 valid attribute set specifier; otherwise the function returns -1.
5321 The grammar of the PQF is as follows:
5324 query ::= top-set query-struct.
5326 top-set ::= [ '@attrset' string ]
5328 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5330 attr-spec ::= '@attr' [ string ] string query-struct
5332 complex ::= operator query-struct query-struct.
5334 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5336 simple ::= result-set | term.
5338 result-set ::= '@set' string.
5342 proximity ::= exclusion distance ordered relation which-code unit-code.
5344 exclusion ::= '1' | '0' | 'void'.
5346 distance ::= integer.
5348 ordered ::= '1' | '0'.
5350 relation ::= integer.
5352 which-code ::= 'known' | 'private' | integer.
5354 unit-code ::= integer.
5356 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5359 You will note that the syntax above is a fairly faithful
5360 representation of RPN, except for the Attribute, which has been
5361 moved a step away from the term, allowing you to associate one or more
5362 attributes with an entire query structure. The parser will
5363 automatically apply the given attributes to each term as required.
5366 The @attr operator is followed by an attribute specification
5367 (<literal>attr-spec</literal> above). The specification consists
5368 of an optional attribute set, an attribute type-value pair and
5369 a sub-query. The attribute type-value pair is packed in one string:
5370 an attribute type, an equals sign, and an attribute value, like this:
5371 <literal>@attr 1=1003</literal>.
5372 The type is always an integer but the value may be either an
5373 integer or a string (if it doesn't start with a digit character).
5374 A string attribute-value is encoded as a Type-1 ``complex''
5375 attribute with the list of values containing the single string
5376 specified, and including no semantic indicators.
5379 Version 3 of the Z39.50 specification defines various encoding of terms.
5380 Use <literal>@term </literal> <replaceable>type</replaceable>
5381 <replaceable>string</replaceable>,
5382 where type is one of: <literal>general</literal>,
5383 <literal>numeric</literal> or <literal>string</literal>
5384 (for InternationalString).
5385 If no term type has been given, the <literal>general</literal> form
5386 is used. This is the only encoding allowed in both versions 2 and 3
5387 of the Z39.50 standard.
5389 <sect3 id="PQF-prox">
5390 <title>Using Proximity Operators with PQF</title>
5393 This is an advanced topic, describing how to construct
5394 queries that make very specific requirements on the
5395 relative location of their operands.
5396 You may wish to skip this section and go straight to
5397 <link linkend="pqf-examples">the example PQF queries</link>.
5402 Most Z39.50 servers do not support proximity searching, or
5403 support only a small subset of the full functionality that
5404 can be expressed using the PQF proximity operator. Be
5405 aware that the ability to <emphasis>express</emphasis> a
5406 query in PQF is no guarantee that any given server will
5407 be able to <emphasis>execute</emphasis> it.
5413 The proximity operator <literal>@prox</literal> is a special
5414 and more restrictive version of the conjunction operator
5415 <literal>@and</literal>. Its semantics are described in
5416 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5417 can be read on-line at
5418 <ulink url="&url.z39.50.proximity;"/>
5421 In PQF, the proximity operation is represented by a sequence
5424 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5426 in which the meanings of the parameters are as described in in
5427 the standard, and they can take the following values:
5430 <formalpara><title>exclusion</title>
5432 0 = false (i.e. the proximity condition specified by the
5433 remaining parameters must be satisfied) or
5434 1 = true (the proximity condition specified by the
5435 remaining parameters must <emphasis>not</emphasis> be
5441 <formalpara><title>distance</title><para>
5442 An integer specifying the difference between the locations
5443 of the operands: e.g. two adjacent words would have
5444 distance=1 since their locations differ by one unit.
5446 </formalpara></listitem>
5448 <formalpara><title>ordered</title><para>
5449 1 = ordered (the operands must occur in the order the
5450 query specifies them) or
5451 0 = unordered (they may appear in either order).
5456 <formalpara><title>relation</title><para>
5457 Recognised values are
5459 2 (lessThanOrEqual),
5461 4 (greaterThanOrEqual),
5468 <formalpara><title>which-code</title><para>
5469 <literal>known</literal>
5471 <literal>k</literal>
5472 (the unit-code parameter is taken from the well-known list
5473 of alternatives described in below) or
5474 <literal>private</literal>
5476 <literal>p</literal>
5477 (the unit-code paramater has semantics specific to an
5478 out-of-band agreement such as a profile).
5483 <formalpara><title>unit-code</title><para>
5484 If the which-code parameter is <literal>known</literal>
5485 then the recognised values are
5495 10 (elementType) and
5497 If which-code is <literal>private</literal> then the
5498 acceptable values are determined by the profile.
5503 (The numeric values of the relation and well-known unit-code
5504 parameters are taken straight from
5505 <ulink url="&url.z39.50.proximity.asn1;"
5506 >the ASN.1</ulink> of the proximity structure in the standard.)
5509 <sect3 id="pqf-examples">
5510 <title>PQF queries</title>
5511 <example id="example.pqf.simple.terms">
5512 <title>PQF queries using simple terms</title>
5521 <example id="pqf.example.pqf.boolean.operators">
5522 <title>PQF boolean operators</title>
5525 @or "dylan" "zimmerman"
5527 @and @or dylan zimmerman when
5529 @and when @or dylan zimmerman
5533 <example id="example.pqf.result.sets">
5534 <title>PQF references to result sets</title>
5539 @and @set seta @set setb
5543 <example id="example.pqf.attributes">
5544 <title>Attributes for terms</title>
5549 @attr 1=4 @attr 4=1 "self portrait"
5551 @attrset exp1 @attr 1=1 CategoryList
5553 @attr gils 1=2008 Copenhagen
5555 @attr 1=/book/title computer
5559 <example id="example.pqf.proximity">
5560 <title>PQF Proximity queries</title>
5563 @prox 0 3 1 2 k 2 dylan zimmerman
5565 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5566 distance, ordered, relation, which-code and unit-code, in that
5570 <para>exclusion = 0: the proximity condition must hold</para>
5573 <para>distance = 3: the terms must be three units apart</para>
5577 ordered = 1: they must occur in the order they are specified
5582 relation = 2: lessThanOrEqual (to the distance of 3 units)
5587 which-code is ``known'', so the standard unit-codes are used
5591 <para>unit-code = 2: word.</para>
5594 So the whole proximity query means that the words
5595 <literal>dylan</literal> and <literal>zimmerman</literal> must
5596 both occur in the record, in that order, differing in position
5597 by three or fewer words (i.e. with two or fewer words between
5598 them.) The query would find ``Bob Dylan, aka. Robert
5599 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5600 since the distance in this case is four.
5603 <example id="example.pqf.search.term.type">
5604 <title>PQF specification of search term type</title>
5607 @term string "a UTF-8 string, maybe?"
5611 <example id="example.pqf.mixed.queries">
5612 <title>PQF mixed queries</title>
5615 @or @and bob dylan @set Result-1
5617 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5619 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5621 The last of these examples is a spatial search: in
5622 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5623 >the GILS attribute set</ulink>,
5625 2038 indicates West Bounding Coordinate and
5626 2030 indicates East Bounding Coordinate,
5627 so the query is for areas extending from -114 degrees
5628 to no more than -109 degrees.
5633 <sect2 id="CCL"><title>CCL</title>
5635 Not all users enjoy typing in prefix query structures and numerical
5636 attribute values, even in a minimalistic test client. In the library
5637 world, the more intuitive Common Command Language - CCL (ISO 8777)
5638 has enjoyed some popularity - especially before the widespread
5639 availability of graphical interfaces. It is still useful in
5640 applications where you for some reason or other need to provide a
5641 symbolic language for expressing boolean query structures.
5643 <sect3 id="ccl.syntax">
5644 <title>CCL Syntax</title>
5646 The CCL parser obeys the following grammar for the FIND argument.
5647 The syntax is annotated by in the lines prefixed by
5648 <literal>--</literal>.
5651 CCL-Find ::= CCL-Find Op Elements
5654 Op ::= "and" | "or" | "not"
5655 -- The above means that Elements are separated by boolean operators.
5657 Elements ::= '(' CCL-Find ')'
5660 | Qualifiers Relation Terms
5661 | Qualifiers Relation '(' CCL-Find ')'
5662 | Qualifiers '=' string '-' string
5663 -- Elements is either a recursive definition, a result set reference, a
5664 -- list of terms, qualifiers followed by terms, qualifiers followed
5665 -- by a recursive definition or qualifiers in a range (lower - upper).
5667 Set ::= 'set' = string
5668 -- Reference to a result set
5670 Terms ::= Terms Prox Term
5672 -- Proximity of terms.
5674 Term ::= Term string
5676 -- This basically means that a term may include a blank
5678 Qualifiers ::= Qualifiers ',' string
5680 -- Qualifiers is a list of strings separated by comma
5682 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5683 -- Relational operators. This really doesn't follow the ISO8777
5687 -- Proximity operator
5690 <example id="example.ccl.queries">
5691 <title>CCL queries</title>
5693 The following queries are all valid:
5704 (dylan and bob) or set=1
5713 Assuming that the qualifiers <literal>ti</literal>,
5714 <literal>au</literal>
5715 and <literal>date</literal> are defined we may use:
5720 au=(bob dylan and slow train coming)
5722 date>1980 and (ti=((self portrait)))
5726 <sect3 id="ccl.qualifiers">
5727 <title>CCL Qualifiers</title>
5729 Qualifiers are used to direct the search to a particular searchable
5730 index, such as title (ti) and author indexes (au). The CCL standard
5731 itself doesn't specify a particular set of qualifiers, but it does
5732 suggest a few short-hand notations. You can customize the CCL parser
5733 to support a particular set of qualifiers to reflect the current target
5734 profile. Traditionally, a qualifier would map to a particular
5735 use-attribute within the BIB-1 attribute set. It is also
5736 possible to set other attributes, such as the structure
5740 A CCL profile is a set of predefined CCL qualifiers that may be
5741 read from a file or set in the CCL API.
5742 The YAZ client reads its CCL qualifiers from a file named
5743 <filename>default.bib</filename>. There are four types of
5744 lines in a CCL profile: qualifier specification,
5745 qualifier alias, comments and directives.
5747 <sect4 id="ccl.qualifier.specification">
5748 <title>Qualifier specification</title>
5750 A qualifier specification is of the form:
5753 <replaceable>qualifier-name</replaceable>
5754 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5755 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5758 where <replaceable>qualifier-name</replaceable> is the name of the
5759 qualifier to be used (eg. <literal>ti</literal>),
5760 <replaceable>type</replaceable> is attribute type in the attribute
5761 set (Bib-1 is used if no attribute set is given) and
5762 <replaceable>val</replaceable> is attribute value.
5763 The <replaceable>type</replaceable> can be specified as an
5764 integer or as it be specified either as a single-letter:
5765 <literal>u</literal> for use,
5766 <literal>r</literal> for relation,<literal>p</literal> for position,
5767 <literal>s</literal> for structure,<literal>t</literal> for truncation
5768 or <literal>c</literal> for completeness.
5769 The attributes for the special qualifier name <literal>term</literal>
5770 are used when no CCL qualifier is given in a query.
5771 <table id="ccl.common.bib1.attributes">
5772 <title>Common Bib-1 attributes</title>
5774 <colspec colwidth="2*" colname="type"></colspec>
5775 <colspec colwidth="9*" colname="description"></colspec>
5779 <entry>Description</entry>
5784 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5786 Use attribute (1). Common use attributes are
5787 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5788 62 Subject, 1003 Author), 1016 Any. Specify value
5793 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5795 Relation attribute (2). Common values are
5796 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5797 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5801 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5803 Position attribute (3). Values: 1 first in field, 2
5804 first in any subfield, 3 any position in field.
5808 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5810 Structure attribute (4). Values: 1 phrase, 2 word,
5811 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5812 101 name (norm), 102 name (un), 103 structure, 104 urx,
5813 105 free-form-text, 106 document-text, 107 local-number,
5814 108 string, 109 numeric string.
5818 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5820 Truncation attribute (5). Values: 1 right, 2 left,
5821 3 left& right, 100 none, 101 process #, 102 regular-1,
5822 103 regular-2, 104 CCL.
5826 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5828 Completeness attribute (6). Values: 1 incomplete subfield,
5829 2 complete subfield, 3 complete field.
5837 Refer to <xref linkend="bib1"/> or the complete
5838 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5841 It is also possible to specify non-numeric attribute values,
5842 which are used in combination with certain types.
5843 The special combinations are:
5844 <table id="ccl.special.attribute.combos">
5845 <title>Special attribute combos</title>
5847 <colspec colwidth="2*" colname="name"></colspec>
5848 <colspec colwidth="9*" colname="description"></colspec>
5852 <entry>Description</entry>
5857 <entry><literal>s=pw</literal></entry>
5859 The structure is set to either word or phrase depending
5860 on the number of tokens in a term (phrase-word).
5864 <entry><literal>s=al</literal></entry>
5866 Each token in the term is ANDed. (and-list).
5867 This does not set the structure at all.
5870 <row><entry><literal>s=ol</literal></entry>
5872 Each token in the term is ORed. (or-list).
5873 This does not set the structure at all.
5876 <row><entry><literal>s=ag</literal></entry>
5878 Tokens that appears as phrases (with blank in them) gets
5879 structure phrase attached (4=1). Tokens that appear to be words
5880 gets structure word attached (4=2). Phrases and words are
5881 ANDed. This is a variant of s=al and s=pw, with the main
5882 difference that words are not split (with operator AND)
5883 but instead kept in one RPN token. This facility appeared
5887 <row><entry><literal>s=sl</literal></entry>
5889 Tokens are split into sub-phrases of all combinations - in order.
5890 This facility appeared in YAZ 5.14.0.
5893 <row><entry><literal>r=o</literal></entry>
5895 Allows ranges and the operators greather-than, less-than, ...
5897 This sets Bib-1 relation attribute accordingly (relation
5898 ordered). A query construct is only treated as a range if
5899 dash is used and that is surrounded by white-space. So
5900 <literal>-1980</literal> is treated as term
5901 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5902 If <literal>- 1980</literal> is used, however, that is
5906 <row><entry><literal>r=r</literal></entry>
5908 Similar to <literal>r=o</literal> but assumes that terms
5909 are non-negative (not prefixed with <literal>-</literal>).
5910 Thus, a dash will always be treated as a range.
5911 The construct <literal>1980-1990</literal> is
5912 treated as a range with <literal>r=r</literal> but as a
5913 single term <literal>"1980-1990"</literal> with
5914 <literal>r=o</literal>. The special attribute
5915 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5918 <row><entry><literal>r=omiteq</literal></entry>
5920 This will omit relation=equals (@attr 2=3) when r=o / r=r
5921 is used. This is useful for servers that somehow breaks
5922 when an explicit relation=equals is used. Omitting the
5923 relation is usually safe because "equals" is the default
5924 behavior. This tweak was added in YAZ version 5.1.2.
5927 <row><entry><literal>t=l</literal></entry>
5929 Allows term to be left-truncated.
5930 If term is of the form <literal>?x</literal>, the resulting
5931 Type-1 term is <literal>x</literal> and truncation is left.
5934 <row><entry><literal>t=r</literal></entry>
5936 Allows term to be right-truncated.
5937 If term is of the form <literal>x?</literal>, the resulting
5938 Type-1 term is <literal>x</literal> and truncation is right.
5941 <row><entry><literal>t=n</literal></entry>
5943 If term is does not include <literal>?</literal>, the
5944 truncation attribute is set to none (100).
5947 <row><entry><literal>t=b</literal></entry>
5949 Allows term to be both left&right truncated.
5950 If term is of the form <literal>?x?</literal>, the
5951 resulting term is <literal>x</literal> and trunctation is
5952 set to both left&right.
5955 <row><entry><literal>t=x</literal></entry>
5957 Allows masking anywhere in a term, thus fully supporting
5958 # (mask one character) and ? (zero or more of any).
5959 If masking is used, trunction is set to 102 (regexp-1 in term)
5960 and the term is converted accordingly to a regular expression.
5963 <row><entry><literal>t=z</literal></entry>
5965 Allows masking anywhere in a term, thus fully supporting
5966 # (mask one character) and ? (zero or more of any).
5967 If masking is used, trunction is set to 104 (Z39.58 in term)
5968 and the term is converted accordingly to Z39.58 masking term -
5969 actually the same truncation as CCL itself.
5976 <example id="example.ccl.profile">
5977 <title>CCL profile</title>
5979 Consider the following definition:
5989 <literal>ti</literal> and <literal>au</literal> both set
5990 structure attribute to phrase (s=1).
5991 <literal>ti</literal>
5992 sets the use-attribute to 4. <literal>au</literal> sets the
5994 When no qualifiers are used in the query the structure-attribute is
5995 set to free-form-text (105) (rule for <literal>term</literal>).
5996 The <literal>date</literal> sets the relation attribute to
5997 the relation used in the CCL query and sets the use attribute
6001 You can combine attributes. To Search for "ranked title" you
6004 ti,ranked=knuth computer
6006 which will set relation=ranked, use=title, structure=phrase.
6013 is a valid query. But
6021 <sect4 id="ccl.qualifier.alias">
6022 <title>Qualifier alias</title>
6024 A qualifier alias is of the form:
6027 <replaceable>q</replaceable>
6028 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
6031 which declares <replaceable>q</replaceable> to
6032 be an alias for <replaceable>q1</replaceable>,
6033 <replaceable>q2</replaceable>... such that the CCL
6034 query <replaceable>q=x</replaceable> is equivalent to
6035 <replaceable>q1=x or q2=x or ...</replaceable>.
6038 <sect4 id="ccl.comments">
6039 <title>Comments</title>
6041 Lines with white space or lines that begin with
6042 character <literal>#</literal> are treated as comments.
6045 <sect4 id="ccl.directives">
6046 <title>Directives</title>
6048 Directive specifications takes the form
6050 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
6052 <table id="ccl.directives.table">
6053 <title>CCL directives</title>
6055 <colspec colwidth="2*" colname="name"></colspec>
6056 <colspec colwidth="8*" colname="description"></colspec>
6057 <colspec colwidth="1*" colname="default"></colspec>
6061 <entry>Description</entry>
6062 <entry>Default</entry>
6067 <entry>truncation</entry>
6068 <entry>Truncation character</entry>
6069 <entry><literal>?</literal></entry>
6073 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
6074 <entry><literal>#</literal></entry>
6077 <entry>field</entry>
6078 <entry>Specifies how multiple fields are to be
6079 combined. There are two modes: <literal>or</literal>:
6080 multiple qualifier fields are ORed,
6081 <literal>merge</literal>: attributes for the qualifier
6082 fields are merged and assigned to one term.
6084 <entry><literal>merge</literal></entry>
6088 <entry>Specifies if CCL operators and qualifiers should be
6089 compared with case sensitivity or not. Specify 1 for
6090 case sensitive; 0 for case insensitive.</entry>
6091 <entry><literal>1</literal></entry>
6095 <entry>Specifies token for CCL operator AND.</entry>
6096 <entry><literal>and</literal></entry>
6100 <entry>Specifies token for CCL operator OR.</entry>
6101 <entry><literal>or</literal></entry>
6105 <entry>Specifies token for CCL operator NOT.</entry>
6106 <entry><literal>not</literal></entry>
6110 <entry>Specifies token for CCL operator SET.</entry>
6111 <entry><literal>set</literal></entry>
6118 <sect3 id="ccl.api">
6119 <title>CCL API</title>
6121 All public definitions can be found in the header file
6122 <filename>ccl.h</filename>. A profile identifier is of type
6123 <literal>CCL_bibset</literal>. A profile must be created with the call
6124 to the function <function>ccl_qual_mk</function> which returns a profile
6125 handle of type <literal>CCL_bibset</literal>.
6128 To read a file containing qualifier definitions the function
6129 <function>ccl_qual_file</function> may be convenient. This function
6130 takes an already opened <literal>FILE</literal> handle pointer as
6131 argument along with a <literal>CCL_bibset</literal> handle.
6134 To parse a simple string with a FIND query use the function
6137 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
6138 int *error, int *pos);
6141 which takes the CCL profile (<literal>bibset</literal>) and query
6142 (<literal>str</literal>) as input. Upon successful completion the RPN
6143 tree is returned. If an error occur, such as a syntax error, the integer
6144 pointed to by <literal>error</literal> holds the error code and
6145 <literal>pos</literal> holds the offset inside query string in which
6149 An English representation of the error may be obtained by calling
6150 the <literal>ccl_err_msg</literal> function. The error codes are
6151 listed in <filename>ccl.h</filename>.
6154 To convert the CCL RPN tree (type
6155 <literal>struct ccl_rpn_node *</literal>)
6156 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
6157 must be used. This function which is part of YAZ is implemented in
6158 <filename>yaz-ccl.c</filename>.
6159 After calling this function the CCL RPN tree is probably no longer
6160 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
6163 A CCL profile may be destroyed by calling the
6164 <function>ccl_qual_rm</function> function.
6167 The token names for the CCL operators may be changed by setting the
6168 globals (all type <literal>char *</literal>)
6169 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
6170 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
6171 An operator may have aliases, i.e. there may be more than one name for
6172 the operator. To do this, separate each alias with a space character.
6179 <ulink url="&url.cql;">CQL</ulink>
6180 - Common Query Language - was defined for the
6181 <ulink url="&url.sru;">SRU</ulink> protocol.
6182 In many ways CQL has a similar syntax to CCL.
6183 The objective of CQL is different. Where CCL aims to be
6184 an end-user language, CQL is <emphasis>the</emphasis> protocol
6185 query language for SRU.
6189 If you are new to CQL, read the
6190 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6194 The CQL parser in &yaz; provides the following:
6198 It parses and validates a CQL query.
6203 It generates a C structure that allows you to convert
6204 a CQL query to some other query language, such as SQL.
6209 The parser converts a valid CQL query to PQF, thus providing a
6210 way to use CQL for both SRU servers and Z39.50 targets at the
6216 The parser converts CQL to XCQL.
6217 XCQL is an XML representation of CQL.
6218 XCQL is part of the SRU specification. However, since SRU
6219 supports CQL only, we don't expect XCQL to be widely used.
6220 Furthermore, CQL has the advantage over XCQL that it is
6226 <sect3 id="cql.parsing">
6227 <title>CQL parsing</title>
6229 A CQL parser is represented by the <literal>CQL_parser</literal>
6230 handle. Its contents should be considered &yaz; internal (private).
6232 #include <yaz/cql.h>
6234 typedef struct cql_parser *CQL_parser;
6236 CQL_parser cql_parser_create(void);
6237 void cql_parser_destroy(CQL_parser cp);
6239 A parser is created by <function>cql_parser_create</function> and
6240 is destroyed by <function>cql_parser_destroy</function>.
6243 To parse a CQL query string, the following function
6246 int cql_parser_string(CQL_parser cp, const char *str);
6248 A CQL query is parsed by the <function>cql_parser_string</function>
6249 which takes a query <parameter>str</parameter>.
6250 If the query was valid (no syntax errors), then zero is returned;
6251 otherwise -1 is returned to indicate a syntax error.
6255 int cql_parser_stream(CQL_parser cp,
6256 int (*getbyte)(void *client_data),
6257 void (*ungetbyte)(int b, void *client_data),
6260 int cql_parser_stdio(CQL_parser cp, FILE *f);
6262 The functions <function>cql_parser_stream</function> and
6263 <function>cql_parser_stdio</function> parses a CQL query
6264 - just like <function>cql_parser_string</function>.
6265 The only difference is that the CQL query can be
6266 fed to the parser in different ways.
6267 The <function>cql_parser_stream</function> uses a generic
6268 byte stream as input. The <function>cql_parser_stdio</function>
6269 uses a <literal>FILE</literal> handle which is opened for reading.
6272 <sect3 id="cql.tree">
6273 <title>CQL tree</title>
6275 The the query string is valid, the CQL parser
6276 generates a tree representing the structure of the
6281 struct cql_node *cql_parser_result(CQL_parser cp);
6283 <function>cql_parser_result</function> returns the
6284 a pointer to the root node of the resulting tree.
6287 Each node in a CQL tree is represented by a
6288 <literal>struct cql_node</literal>.
6289 It is defined as follows:
6291 #define CQL_NODE_ST 1
6292 #define CQL_NODE_BOOL 2
6293 #define CQL_NODE_SORT 3
6303 struct cql_node *modifiers;
6307 struct cql_node *left;
6308 struct cql_node *right;
6309 struct cql_node *modifiers;
6313 struct cql_node *next;
6314 struct cql_node *modifiers;
6315 struct cql_node *search;
6320 There are three node types: search term (ST), boolean (BOOL)
6322 A modifier is treated as a search term too.
6325 The search term node has five members:
6329 <literal>index</literal>: index for search term.
6330 If an index is unspecified for a search term,
6331 <literal>index</literal> will be NULL.
6336 <literal>index_uri</literal>: index URi for search term
6337 or NULL if none could be resolved for the index.
6342 <literal>term</literal>: the search term itself.
6347 <literal>relation</literal>: relation for search term.
6352 <literal>relation_uri</literal>: relation URI for search term.
6357 <literal>modifiers</literal>: relation modifiers for search
6358 term. The <literal>modifiers</literal> list itself of cql_nodes
6359 each of type <literal>ST</literal>.
6365 The boolean node represents <literal>and</literal>,
6366 <literal>or</literal>, <literal>not</literal> +
6371 <literal>left</literal> and <literal>right</literal>: left
6372 - and right operand respectively.
6377 <literal>modifiers</literal>: proximity arguments.
6383 The sort node represents both the SORTBY clause.
6386 <sect3 id="cql.to.pqf">
6387 <title>CQL to PQF conversion</title>
6389 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6390 that the resulting RPN depends on the Z39.50 target
6391 capabilities (combinations of supported attributes).
6392 In addition, the CQL and SRU operates on index prefixes
6393 (URI or strings), whereas the RPN uses Object Identifiers
6397 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6398 type. It represents a particular mapping between CQL and RPN.
6399 This handle is created and destroyed by the functions:
6401 cql_transform_t cql_transform_open_FILE (FILE *f);
6402 cql_transform_t cql_transform_open_fname(const char *fname);
6403 void cql_transform_close(cql_transform_t ct);
6405 The first two functions create a tranformation handle from
6406 either an already open FILE or from a filename respectively.
6409 The handle is destroyed by <function>cql_transform_close</function>
6410 in which case no further reference of the handle is allowed.
6413 When a <literal>cql_transform_t</literal> handle has been created
6414 you can convert to RPN.
6416 int cql_transform_buf(cql_transform_t ct,
6417 struct cql_node *cn, char *out, int max);
6419 This function converts the CQL tree <literal>cn</literal>
6420 using handle <literal>ct</literal>.
6421 For the resulting PQF, you supply a buffer <literal>out</literal>
6422 which must be able to hold at at least <literal>max</literal>
6426 If conversion failed, <function>cql_transform_buf</function>
6427 returns a non-zero SRU error code; otherwise zero is returned
6428 (conversion successful). The meanings of the numeric error
6429 codes are listed in the SRU specification somewhere (no
6430 direct link anymore).
6433 If conversion fails, more information can be obtained by calling
6435 int cql_transform_error(cql_transform_t ct, char **addinfop);
6437 This function returns the most recently returned numeric
6438 error-code and sets the string-pointer at
6439 <literal>*addinfop</literal> to point to a string containing
6440 additional information about the error that occurred: for
6441 example, if the error code is 15 (``Illegal or unsupported context
6442 set''), the additional information is the name of the requested
6443 context set that was not recognised.
6446 The SRU error-codes may be translated into brief human-readable
6447 error messages using
6449 const char *cql_strerror(int code);
6453 If you wish to be able to produce a PQF result in a different
6454 way, there are two alternatives.
6456 void cql_transform_pr(cql_transform_t ct,
6457 struct cql_node *cn,
6458 void (*pr)(const char *buf, void *client_data),
6461 int cql_transform_FILE(cql_transform_t ct,
6462 struct cql_node *cn, FILE *f);
6464 The former function produces output to a user-defined
6465 output stream. The latter writes the result to an already
6466 open <literal>FILE</literal>.
6469 <sect3 id="cql.to.rpn">
6470 <title>Specification of CQL to RPN mappings</title>
6472 The file supplied to functions
6473 <function>cql_transform_open_FILE</function>,
6474 <function>cql_transform_open_fname</function> follows
6475 a structure found in many Unix utilities.
6476 It consists of mapping specifications - one per line.
6477 Lines starting with <literal>#</literal> are ignored (comments).
6480 Each line is of the form
6482 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6486 An RPN pattern is a simple attribute list. Each attribute pair
6489 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6491 The attribute <replaceable>set</replaceable> is optional.
6492 The <replaceable>type</replaceable> is the attribute type,
6493 <replaceable>value</replaceable> the attribute value.
6496 The character <literal>*</literal> (asterisk) has special meaning
6497 when used in the RPN pattern.
6498 Each occurrence of <literal>*</literal> is substituted with the
6499 CQL matching name (index, relation, qualifier etc).
6500 This facility can be used to copy a CQL name verbatim to the RPN result.
6503 The following CQL patterns are recognized:
6507 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6511 This pattern is invoked when a CQL index, such as
6512 dc.title is converted. <replaceable>set</replaceable>
6513 and <replaceable>name</replaceable> are the context set and index
6515 Typically, the RPN specifies an equivalent use attribute.
6518 For terms not bound by an index the pattern
6519 <literal>index.cql.serverChoice</literal> is used.
6520 Here, the prefix <literal>cql</literal> is defined as
6521 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6522 If this pattern is not defined, the mapping will fail.
6526 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6527 is used when no other index pattern is matched.
6533 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6538 For backwards compatibility, this is recognised as a synonym of
6539 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6545 <literal>relation.</literal><replaceable>relation</replaceable>
6549 This pattern specifies how a CQL relation is mapped to RPN.
6550 <replaceable>pattern</replaceable> is name of relation
6551 operator. Since <literal>=</literal> is used as
6552 separator between CQL pattern and RPN, CQL relations
6553 including <literal>=</literal> cannot be
6554 used directly. To avoid a conflict, the names
6555 <literal>ge</literal>,
6556 <literal>eq</literal>,
6557 <literal>le</literal>,
6558 must be used for CQL operators, greater-than-or-equal,
6559 equal, less-than-or-equal respectively.
6560 The RPN pattern is supposed to include a relation attribute.
6563 For terms not bound by a relation, the pattern
6564 <literal>relation.scr</literal> is used. If the pattern
6565 is not defined, the mapping will fail.
6568 The special pattern, <literal>relation.*</literal> is used
6569 when no other relation pattern is matched.
6575 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6579 This pattern specifies how a CQL relation modifier is mapped to RPN.
6580 The RPN pattern is usually a relation attribute.
6586 <literal>structure.</literal><replaceable>type</replaceable>
6590 This pattern specifies how a CQL structure is mapped to RPN.
6591 Note that this CQL pattern is somewhat to similar to
6592 CQL pattern <literal>relation</literal>.
6593 The <replaceable>type</replaceable> is a CQL relation.
6596 The pattern, <literal>structure.*</literal> is used
6597 when no other structure pattern is matched.
6598 Usually, the RPN equivalent specifies a structure attribute.
6604 <literal>position.</literal><replaceable>type</replaceable>
6608 This pattern specifies how the anchor (position) of
6609 CQL is mapped to RPN.
6610 The <replaceable>type</replaceable> is one
6611 of <literal>first</literal>, <literal>any</literal>,
6612 <literal>last</literal>, <literal>firstAndLast</literal>.
6615 The pattern, <literal>position.*</literal> is used
6616 when no other position pattern is matched.
6622 <literal>set.</literal><replaceable>prefix</replaceable>
6626 This specification defines a CQL context set for a given prefix.
6627 The value on the right hand side is the URI for the set -
6628 <emphasis>not</emphasis> RPN. All prefixes used in
6629 index patterns must be defined this way.
6635 <literal>set</literal>
6639 This specification defines a default CQL context set for index names.
6640 The value on the right hand side is the URI for the set.
6646 <example id="example.cql.to.rpn.mapping">
6647 <title>CQL to RPN mapping file</title>
6649 This simple file defines two context sets, three indexes and three
6650 relations, a position pattern and a default structure.
6652 <programlisting><![CDATA[
6653 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6654 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6656 index.cql.serverChoice = 1=1016
6657 index.dc.title = 1=4
6658 index.dc.subject = 1=21
6664 position.any = 3=3 6=1
6670 With the mappings above, the CQL query
6674 is converted to the PQF:
6676 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6678 by rules <literal>index.cql.serverChoice</literal>,
6679 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6680 <literal>position.any</literal>.
6687 is rejected, since <literal>position.right</literal> is
6693 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6697 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6701 <example id="example.cql.to.rpn.string">
6702 <title>CQL to RPN string attributes</title>
6704 In this example we allow any index to be passed to RPN as
6707 <programlisting><![CDATA[
6708 # Identifiers for prefixes used in this file. (index.*)
6709 set.cql = info:srw/cql-context-set/1/cql-v1.1
6710 set.rpn = http://bogus/rpn
6711 set = http://bogus/rpn
6713 # The default index when none is specified by the query
6714 index.cql.serverChoice = 1=any
6723 The <literal>http://bogus/rpn</literal> context set is also the default
6724 so we can make queries such as
6728 which is converted to
6730 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6734 <example id="example.cql.to.rpn.bathprofile">
6735 <title>CQL to RPN using Bath Profile</title>
6737 The file <filename>etc/pqf.properties</filename> has mappings from
6738 the Bath Profile and Dublin Core to RPN.
6739 If YAZ is installed as a package it's usually located
6740 in <filename>/usr/share/yaz/etc</filename> and part of the
6741 development package, such as <literal>libyaz-dev</literal>.
6745 <sect3 id="cql.xcql">
6746 <title>CQL to XCQL conversion</title>
6748 Conversion from CQL to XCQL is trivial and does not
6749 require a mapping to be defined.
6750 There three functions to choose from depending on the
6751 way you wish to store the resulting output (XML buffer
6754 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6755 void cql_to_xml(struct cql_node *cn,
6756 void (*pr)(const char *buf, void *client_data),
6758 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6760 Function <function>cql_to_xml_buf</function> converts
6761 to XCQL and stores result in a user supplied buffer of a given
6765 <function>cql_to_xml</function> writes the result in
6766 a user defined output stream.
6767 <function>cql_to_xml_stdio</function> writes to a
6771 <sect3 id="rpn.to.cql">
6772 <title>PQF to CQL conversion</title>
6774 Conversion from PQF to CQL is offered by the two functions shown
6775 below. The former uses a generic stream for result. The latter
6776 puts result in a WRBUF (string container).
6778 #include <yaz/rpn2cql.h>
6780 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6781 void (*pr)(const char *buf, void *client_data),
6785 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6789 The configuration is the same as used in CQL to PQF conversions.
6794 <sect1 id="tools.oid">
6795 <title>Object Identifiers</title>
6797 The basic YAZ representation of an OID is an array of integers,
6798 terminated with the value -1. This integer is of type
6799 <literal>Odr_oid</literal>.
6802 Fundamental OID operations and the type <literal>Odr_oid</literal>
6803 are defined in <filename>yaz/oid_util.h</filename>.
6806 An OID can either be declared as a automatic variable or it can
6807 allocated using the memory utilities or ODR/NMEM. It's
6808 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6810 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6812 We can create an OID for the Bib-1 attribute set with:
6814 Odr_oid bib1[OID_SIZE];
6826 And OID may also be filled from a string-based representation using
6827 dots (.). This is achieved by function
6829 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6831 This functions returns 0 if name could be converted; -1 otherwise.
6833 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6835 We can fill the Bib-1 attribute set OID easier with:
6837 Odr_oid bib1[OID_SIZE];
6838 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6843 We can also allocate an OID dynamically on a ODR stream with:
6845 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6847 This creates an OID from string-based representation using dots.
6848 This function take an &odr; stream as parameter. This stream is used to
6849 allocate memory for the data elements, which is released on a
6850 subsequent call to <function>odr_reset()</function> on that stream.
6852 <example id="tools.oid.bib1.3">
6853 <title>Using odr_getoidbystr</title>
6855 We can create a OID for the Bib-1 attribute set with:
6857 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6864 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6866 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6867 converts an OID to the string-based representation using dots.
6868 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6869 string and must be at least <literal>OID_STR_MAX</literal> in size.
6872 OIDs can be copied with <function>oid_oidcpy</function> which takes
6873 two OID lists as arguments. Alternativly, an OID copy can be allocated
6874 on a ODR stream with:
6876 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6880 OIDs can be compared with <function>oid_oidcmp</function> which returns
6881 zero if the two OIDs provided are identical; non-zero otherwise.
6883 <sect2 id="tools.oid.database">
6884 <title>OID database</title>
6886 From YAZ version 3 and later, the oident system has been replaced
6887 by an OID database. OID database is a misnomer .. the old odient
6888 system was also a database.
6891 The OID database is really just a map between named Object Identifiers
6892 (string) and their OID raw equivalents. Most operations either
6893 convert from string to OID or other way around.
6896 Unfortunately, whenever we supply a string we must also specify the
6897 <emphasis>OID class</emphasis>. The class is necessary because some
6898 strings correspond to multiple OIDs. An example of such a string is
6899 <literal>Bib-1</literal> which may either be an attribute-set
6900 or a diagnostic-set.
6903 Applications using the YAZ database should include
6904 <filename>yaz/oid_db.h</filename>.
6907 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6908 Actually that's a pointer. You need not think deal with that.
6909 YAZ has a built-in database which can be considered "constant" for
6911 We can get hold that by using function <function>yaz_oid_std</function>.
6914 All functions with prefix <function>yaz_string_to_oid</function>
6915 converts from class + string to OID. We have variants of this
6916 operation due to different memory allocation strategies.
6919 All functions with prefix
6920 <function>yaz_oid_to_string</function> converts from OID to string
6923 <example id="tools.oid.bib1.4">
6924 <title>Create OID with YAZ DB</title>
6926 We can create an OID for the Bib-1 attribute set on the ODR stream
6930 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6932 This is more complex than using <function>odr_getoidbystr</function>.
6933 You would only use <function>yaz_string_to_oid_odr</function> when the
6934 string (here Bib-1) is supplied by a user or configuration.
6938 <sect2 id="tools.oid.std">
6939 <title>Standard OIDs</title>
6941 All the object identifers in the standard OID database as returned
6942 by <function>yaz_oid_std</function> can referenced directly in a
6943 program as a constant OID.
6944 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6945 followed by OID class (lowercase) - then by OID name (normalized and
6949 See <xref linkend="list-oids"/> for list of all object identifiers
6951 These are declared in <filename>yaz/oid_std.h</filename> but are
6952 included by <filename>yaz/oid_db.h</filename> as well.
6954 <example id="tools.oid.bib1.5">
6955 <title>Use a built-in OID</title>
6957 We can allocate our own OID filled with the constant OID for
6960 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6966 <sect1 id="tools.nmem">
6967 <title>Nibble Memory</title>
6969 Sometimes when you need to allocate and construct a large,
6970 interconnected complex of structures, it can be a bit of a pain to
6971 release the associated memory again. For the structures describing the
6972 Z39.50 PDUs and related structures, it is convenient to use the
6973 memory-management system of the &odr; subsystem (see
6974 <xref linkend="odr.use"/>). However, in some circumstances
6975 where you might otherwise benefit from using a simple nibble memory
6976 management system, it may be impractical to use
6977 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6978 For this purpose, the memory manager which also supports the &odr;
6979 streams is made available in the NMEM module. The external interface
6980 to this module is given in the <filename>nmem.h</filename> file.
6983 The following prototypes are given:
6986 NMEM nmem_create(void);
6987 void nmem_destroy(NMEM n);
6988 void *nmem_malloc(NMEM n, size_t size);
6989 void nmem_reset(NMEM n);
6990 size_t nmem_total(NMEM n);
6991 void nmem_init(void);
6992 void nmem_exit(void);
6995 The <function>nmem_create()</function> function returns a pointer to a
6996 memory control handle, which can be released again by
6997 <function>nmem_destroy()</function> when no longer needed.
6998 The function <function>nmem_malloc()</function> allocates a block of
6999 memory of the requested size. A call to <function>nmem_reset()</function>
7000 or <function>nmem_destroy()</function> will release all memory allocated
7001 on the handle since it was created (or since the last call to
7002 <function>nmem_reset()</function>. The function
7003 <function>nmem_total()</function> returns the number of bytes currently
7004 allocated on the handle.
7007 The nibble memory pool is shared amongst threads. POSIX
7008 mutex'es and WIN32 Critical sections are introduced to keep the
7009 module thread safe. Function <function>nmem_init()</function>
7010 initializes the nibble memory library and it is called automatically
7011 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
7012 function <function>DllMain</function> to achieve this. You should
7013 <emphasis>not</emphasis> call <function>nmem_init</function> or
7014 <function>nmem_exit</function> unless you're absolute sure what
7015 you're doing. Note that in previous &yaz; versions you'd have to call
7016 <function>nmem_init</function> yourself.
7019 <sect1 id="tools.log">
7022 &yaz; has evolved a fairly complex log system which should be useful both
7023 for debugging &yaz; itself, debugging applications that use &yaz;, and for
7024 production use of those applications.
7027 The log functions are declared in header <filename>yaz/log.h</filename>
7028 and implemented in <filename>src/log.c</filename>.
7029 Due to name clash with syslog and some math utilities the logging
7030 interface has been modified as of YAZ 2.0.29. The obsolete interface
7031 is still available if in header file <filename>yaz/log.h</filename>.
7032 The key points of the interface are:
7035 void yaz_log(int level, const char *fmt, ...)
7036 void yaz_log_init(int level, const char *prefix, const char *name);
7037 void yaz_log_init_file(const char *fname);
7038 void yaz_log_init_level(int level);
7039 void yaz_log_init_prefix(const char *prefix);
7040 void yaz_log_time_format(const char *fmt);
7041 void yaz_log_init_max_size(int mx);
7043 int yaz_log_mask_str(const char *str);
7044 int yaz_log_module_level(const char *name);
7047 The reason for the whole log module is the <function>yaz_log</function>
7048 function. It takes a bitmask indicating the log levels, a
7049 <literal>printf</literal>-like format string, and a variable number of
7053 The <literal>log level</literal> is a bit mask, that says on which level(s)
7054 the log entry should be made, and optionally set some behaviour of the
7055 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
7056 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
7057 that modify the way the log entry is written:<literal>YLOG_ERRNO,
7058 YLOG_NOTIME, YLOG_FLUSH</literal>.
7059 Most of the rest of the bits are deprecated, and should not be used. Use
7060 the dynamic log levels instead.
7063 Applications that use &yaz;, should not use the LOG_LOG for ordinary
7064 messages, but should make use of the dynamic loglevel system. This consists
7065 of two parts, defining the loglevel and checking it.
7068 To define the log levels, the (main) program should pass a string to
7069 <function>yaz_log_mask_str</function> to define which log levels are to be
7070 logged. This string should be a comma-separated list of log level names,
7071 and can contain both hard-coded names and dynamic ones. The log level
7072 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
7073 for each word it meets, unless the word starts with a '-', in which case it
7074 clears the bit. If the string <literal>'none'</literal> is found,
7075 all bits are cleared. Typically this string comes from the command-line,
7076 often identified by <literal>-v</literal>. The
7077 <function>yaz_log_mask_str</function> returns a log level that should be
7078 passed to <function>yaz_log_init_level</function> for it to take effect.
7081 Each module should check what log bits it should be used, by calling
7082 <function>yaz_log_module_level</function> with a suitable name for the
7083 module. The name is cleared from a preceding path and an extension, if any,
7084 so it is quite possible to use <literal>__FILE__</literal> for it. If the
7085 name has been passed to <function>yaz_log_mask_str</function>, the routine
7086 returns a non-zero bitmask, which should then be used in consequent calls
7087 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
7088 yaz_log, in time-critical places, or when the log entry would take time
7092 Yaz uses the following dynamic log levels:
7093 <literal>server, session, request, requestdetail</literal> for the server
7095 <literal>zoom</literal> for the zoom client api.
7096 <literal>ztest</literal> for the simple test server.
7097 <literal>malloc, nmem, odr, eventl</literal> for internal
7098 debugging of yaz itself.
7099 Of course, any program using yaz is welcome to define as many new
7103 By default the log is written to stderr, but this can be changed by a call
7104 to <function>yaz_log_init_file</function> or
7105 <function>yaz_log_init</function>. If the log is directed to a file, the
7106 file size is checked at every write, and if it exceeds the limit given in
7107 <function>yaz_log_init_max_size</function>, the log is rotated. The
7108 rotation keeps one old version (with a <literal>.1</literal> appended to
7109 the name). The size defaults to 1GB. Setting it to zero will disable the
7113 A typical yaz-log looks like this
7114 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
7115 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
7116 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
7117 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
7118 13:24:13-23/11 yaz-ztest(1) [request] Close OK
7121 The log entries start with a time stamp. This can be omitted by setting the
7122 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
7123 can be hoped to produce identical log files, that are easy to diff. The
7124 format of the time stamp can be set with
7125 <function>yaz_log_time_format</function>, which takes a format string just
7126 like <function>strftime</function>.
7129 Next in a log line comes the prefix, often the name of the program. For
7130 yaz-based servers, it can also contain the session number. Then
7131 comes one or more logbits in square brackets, depending on the logging
7132 level set by <function>yaz_log_init_level</function> and the loglevel
7133 passed to <function>yaz_log_init_level</function>. Finally comes the format
7134 string and additional values passed to <function>yaz_log</function>
7137 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
7138 <literal>loglevel</literal>, will log all the log-level affecting
7139 operations. This can come in handy if you need to know what other log
7140 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
7143 The log system is almost independent of the rest of &yaz;, the only
7144 important dependence is of <filename>nmem</filename>, and that only for
7145 using the semaphore definition there.
7148 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
7149 the same time, the log bit names were changed from
7150 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
7151 to avoid collision with <filename>syslog.h</filename>.
7157 YAZ provides a fast utility for working with MARC records.
7158 Early versions of the MARC utility only allowed decoding of ISO2709.
7159 Today the utility may both encode - and decode to a varity of formats.
7162 #include <yaz/marcdisp.h>
7164 /* create handler */
7165 yaz_marc_t yaz_marc_create(void);
7167 void yaz_marc_destroy(yaz_marc_t mt);
7169 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
7170 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
7171 #define YAZ_MARC_LINE 0
7172 #define YAZ_MARC_SIMPLEXML 1
7173 #define YAZ_MARC_OAIMARC 2
7174 #define YAZ_MARC_MARCXML 3
7175 #define YAZ_MARC_ISO2709 4
7176 #define YAZ_MARC_XCHANGE 5
7177 #define YAZ_MARC_CHECK 6
7178 #define YAZ_MARC_TURBOMARC 7
7179 #define YAZ_MARC_JSON 8
7181 /* supply iconv handle for character set conversion .. */
7182 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
7184 /* set debug level, 0=none, 1=more, 2=even more, .. */
7185 void yaz_marc_debug(yaz_marc_t mt, int level);
7187 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7188 On success, result in *result with size *rsize. */
7189 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7190 const char **result, size_t *rsize);
7192 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7193 On success, result in WRBUF */
7194 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7195 int bsize, WRBUF wrbuf);
7200 The synopsis is just a basic subset of all functionality. Refer
7201 to the actual header file <filename>marcdisp.h</filename> for
7206 A MARC conversion handle must be created by using
7207 <function>yaz_marc_create</function> and destroyed
7208 by calling <function>yaz_marc_destroy</function>.
7211 All other function operate on a <literal>yaz_marc_t</literal> handle.
7212 The output is specified by a call to <function>yaz_marc_xml</function>.
7213 The <literal>xmlmode</literal> must be one of
7216 <term>YAZ_MARC_LINE</term>
7219 A simple line-by-line format suitable for display but not
7220 recommend for further (machine) processing.
7225 <term>YAZ_MARC_MARCXML</term>
7228 <ulink url="&url.marcxml;">MARCXML</ulink>.
7233 <term>YAZ_MARC_ISO2709</term>
7236 ISO2709 (sometimes just referred to as "MARC").
7241 <term>YAZ_MARC_XCHANGE</term>
7244 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7249 <term>YAZ_MARC_CHECK</term>
7252 Pseudo format for validation only. Does not generate
7253 any real output except diagnostics.
7258 <term>YAZ_MARC_TURBOMARC</term>
7261 XML format with same semantics as MARCXML but more compact
7262 and geared towards fast processing with XSLT. Refer to
7263 <xref linkend="tools.turbomarc"/> for more information.
7268 <term>YAZ_MARC_JSON</term>
7271 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7278 The actual conversion functions are
7279 <function>yaz_marc_decode_buf</function> and
7280 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7281 a MARC record. The former function operates on simple buffers, the
7282 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7285 <example id="example.marc.display">
7286 <title>Display of MARC record</title>
7288 The following program snippet illustrates how the MARC API may
7289 be used to convert a MARC record to the line-by-line format:
7290 <programlisting><![CDATA[
7291 void print_marc(const char *marc_buf, int marc_buf_size)
7293 char *result; /* for result buf */
7294 size_t result_len; /* for size of result */
7295 yaz_marc_t mt = yaz_marc_create();
7296 yaz_marc_xml(mt, YAZ_MARC_LINE);
7297 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7298 &result, &result_len);
7299 fwrite(result, result_len, 1, stdout);
7300 yaz_marc_destroy(mt); /* note that result is now freed... */
7306 <sect2 id="tools.turbomarc">
7307 <title>TurboMARC</title>
7309 TurboMARC is yet another XML encoding of a MARC record. The format
7310 was designed for fast processing with XSLT.
7314 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7315 representation. This conversion mostly check the tag of a MARC field
7316 to determine the basic rules in the conversion. This check is
7317 costly when that is tag is encoded as an attribute in MARCXML.
7318 By having the tag value as the element instead, makes processing
7319 many times faster (at least for Libxslt).
7322 TurboMARC is encoded as follows:
7326 Record elements is part of namespace
7327 "<literal>http://www.indexdata.com/turbomarc</literal>".
7332 A record is enclosed in element <literal>r</literal>.
7337 A collection of records is enclosed in element
7338 <literal>collection</literal>.
7343 The leader is encoded as element <literal>l</literal> with the
7344 leader content as its (text) value.
7349 A control field is encoded as element <literal>c</literal> concatenated
7350 with the tag value of the control field if the tag value
7351 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7352 If the tag value do not match the regular expression
7353 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7354 as element <literal>c</literal> and attribute <literal>code</literal>
7355 will hold the tag value.
7356 This rule ensure that in the rare cases where a tag value might
7357 result in a non-wellformed XML YAZ encode it as a coded attribute
7361 The control field content is the the text value of this element.
7362 Indicators are encoded as attribute names
7363 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7364 corresponding values for each indicator.
7369 A data field is encoded as element <literal>d</literal> concatenated
7370 with the tag value of the data field or using the attribute
7371 <literal>code</literal> as described in the rules for control fields.
7372 The children of the data field element is subfield elements.
7373 Each subfield element is encoded as <literal>s</literal>
7374 concatenated with the sub field code.
7375 The text of the subfield element is the contents of the subfield.
7376 Indicators are encoded as attributes for the data field element similar
7377 to the encoding for control fields.
7384 <sect1 id="tools.retrieval">
7385 <title>Retrieval Facility</title>
7387 YAZ version 2.1.20 or later includes a Retrieval facility tool
7388 which allows a SRU/Z39.50 to describe itself and perform record
7389 conversions. The idea is the following:
7393 An SRU/Z39.50 client sends a retrieval request which includes
7394 a combination of the following parameters: syntax (format),
7395 schema (or element set name).
7400 The retrieval facility is invoked with parameters in a
7401 server/proxy. The retrieval facility matches the parameters a set of
7402 "supported" retrieval types.
7403 If there is no match, the retrieval signals an error
7404 (syntax and / or schema not supported).
7409 For a successful match, the backend is invoked with the same
7410 or altered retrieval parameters (syntax, schema). If
7411 a record is received from the backend, it is converted to the
7412 frontend name / syntax.
7417 The resulting record is sent back the client and tagged with
7418 the frontend syntax / schema.
7424 The Retrieval facility is driven by an XML configuration. The
7425 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7426 should be easy to generate both of them from the XML configuration.
7427 (unfortunately the two versions
7428 of ZeeRex differ substantially in this regard).
7430 <sect2 id="tools.retrieval.format">
7431 <title>Retrieval XML format</title>
7433 All elements should be covered by namespace
7434 <literal>http://indexdata.com/yaz</literal> .
7435 The root element node must be <literal>retrievalinfo</literal>.
7438 The <literal>retrievalinfo</literal> must include one or
7439 more <literal>retrieval</literal> elements. Each
7440 <literal>retrieval</literal> defines specific combination of
7441 syntax, name and identifier supported by this retrieval service.
7444 The <literal>retrieval</literal> element may include any of the
7445 following attributes:
7447 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7450 Defines the record syntax. Possible values is any
7451 of the names defined in YAZ' OID database or a raw
7456 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7459 Defines the name of the retrieval format. This can be
7460 any string. For SRU, the value, is equivalent to schema (short-hand);
7461 for Z39.50 it's equivalent to simple element set name.
7462 For YAZ 3.0.24 and later this name may be specified as a glob
7463 expression with operators
7464 <literal>*</literal> and <literal>?</literal>.
7468 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7471 Defines the URI schema name of the retrieval format. This can be
7472 any string. For SRU, the value, is equivalent to URI schema.
7473 For Z39.50, there is no equivalent.
7480 The <literal>retrieval</literal> may include one
7481 <literal>backend</literal> element. If a <literal>backend</literal>
7482 element is given, it specifies how the records are retrieved by
7483 some backend and how the records are converted from the backend to
7487 The attributes, <literal>name</literal> and <literal>syntax</literal>
7488 may be specified for the <literal>backend</literal> element. These
7489 semantics of these attributes is equivalent to those for the
7490 <literal>retrieval</literal>. However, these values are passed to
7494 The <literal>backend</literal> element may includes one or more
7495 conversion instructions (as children elements). The supported
7498 <varlistentry><term><literal>marc</literal></term>
7501 The <literal>marc</literal> element specifies a conversion
7502 to - and from ISO2709 encoded MARC and
7503 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7504 The following attributes may be specified:
7507 <term><literal>inputformat</literal> (REQUIRED)</term>
7510 Format of input. Supported values are
7511 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7512 (MARCXML/MarcXchange) and <literal>json</literal>
7513 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7518 <term><literal>outputformat</literal> (REQUIRED)</term>
7521 Format of output. Supported values are
7522 <literal>line</literal> (MARC line format);
7523 <literal>marcxml</literal> (for MARCXML),
7524 <literal>marc</literal> (ISO2709),
7525 <literal>marcxhcange</literal> (for MarcXchange),
7526 or <literal>json</literal>
7527 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7532 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7535 Encoding of input. For XML input formats, this need not
7536 be given, but for ISO2709 based inputformats, this should
7537 be set to the encoding used. For MARC21 records, a common
7538 inputcharset value would be <literal>marc-8</literal>.
7543 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7546 Encoding of output. If outputformat is XML based, it is
7547 strongly recommened to use <literal>utf-8</literal>.
7556 <term><literal>select</literal></term>
7559 The <literal>select</literal> selects one or more text nodes
7560 and decodes them as XML.
7561 The following attributes may be specified:
7563 <varlistentry><term><literal>path</literal> (REQUIRED)</term>
7566 X-Path expression for selecting text nodes.
7573 This conversion is available in YAZ 5.8.0 and later.
7578 <term><literal>solrmarc</literal></term>
7581 The <literal>solrmarc</literal> decodes solrmarc records.
7582 It assumes that the input is pure solrmarc text (no escaping)
7583 and will convert all sequences of the form #XX; to a single
7584 character of the hexadecimal value as given by XX. The output,
7585 presumably, is a valid ISO2709 buffer.
7588 This conversion is available in YAZ 5.0.21 and later.
7593 <term><literal>xslt</literal></term>
7596 The <literal>xslt</literal> element specifies a conversion
7597 via &acro.xslt;. The following attributes may be specified:
7599 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7613 <sect2 id="tools.retrieval.examples">
7614 <title>Retrieval Facility Examples</title>
7615 <example id="tools.retrieval.marc21">
7616 <title>MARC21 backend</title>
7618 A typical way to use the retrieval facility is to enable XML
7619 for servers that only supports ISO2709 encoded MARC21 records.
7621 <programlisting><![CDATA[
7623 <retrieval syntax="usmarc" name="F"/>
7624 <retrieval syntax="usmarc" name="B"/>
7625 <retrieval syntax="xml" name="marcxml"
7626 identifier="info:srw/schema/1/marcxml-v1.1">
7627 <backend syntax="usmarc" name="F">
7628 <marc inputformat="marc" outputformat="marcxml"
7629 inputcharset="marc-8"/>
7632 <retrieval syntax="xml" name="dc">
7633 <backend syntax="usmarc" name="F">
7634 <marc inputformat="marc" outputformat="marcxml"
7635 inputcharset="marc-8"/>
7636 <xslt stylesheet="MARC21slim2DC.xsl"/>
7643 This means that our frontend supports:
7647 MARC21 F(ull) records.
7652 MARC21 B(rief) records.
7662 Dublin core records.
7668 <example id="tools.retrieval.marcxml">
7669 <title>MARCXML backend</title>
7671 SRW/SRU and Solr backends returns records in XML.
7672 If they return MARCXML or MarcXchange, the retrieval module
7673 can convert those into ISO2709 formats, most commonly USMARC
7675 In this example, the backend returns MARCXML for schema="marcxml".
7677 <programlisting><![CDATA[
7679 <retrieval syntax="usmarc">
7680 <backend syntax="xml" name="marcxml">
7681 <marc inputformat="xml" outputformat="marc"
7682 outputcharset="marc-8"/>
7685 <retrieval syntax="xml" name="marcxml"
7686 identifier="info:srw/schema/1/marcxml-v1.1"/>
7687 <retrieval syntax="xml" name="dc">
7688 <backend syntax="xml" name="marcxml">
7689 <xslt stylesheet="MARC21slim2DC.xsl"/>
7696 This means that our frontend supports:
7700 MARC21 records (any element set name) in MARC-8 encoding.
7705 MARCXML records for element-set=marcxml
7710 Dublin core records for element-set=dc.
7717 <sect2 id="tools.retrieval.api">
7720 It should be easy to use the retrieval systems from applications. Refer
7722 <filename>yaz/retrieval.h</filename> and
7723 <filename>yaz/record_conv.h</filename>.
7727 <sect1 id="sorting">
7728 <title>Sorting</title>
7730 This chapter describes sorting and how it is supported in YAZ.
7731 Sorting applies to a result-set.
7733 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7734 Z39.50 sorting facility
7736 takes one or more input result-sets
7737 and one result-set as output. The most simple case is that
7738 the input-set is the same as the output-set.
7741 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7742 following a search (two phases).
7745 In SRU/Solr, however, the model is different. Here, sorting is specified
7746 during the the search operation. Note, however, that SRU might
7747 perform sort as separate search, by referring to an existing result-set
7748 in the query (result-set reference).
7751 <title>Using the Z39.50 sort service</title>
7753 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7754 case the sort sequence or sort critiera is using a string notation.
7755 This notation is a one-line notation suitable for being manually
7756 entered or generated and allows for easy logging (one liner).
7757 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7758 function. For yaz-client the sort is performed and specified using
7759 the sort and sort+ commands. For description of the sort criteria notation
7760 refer to the <link linkend="sortspec">sort command</link> in the
7764 The ZOOM API might choose one of several sort strategies for
7765 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7769 <title>Type-7 sort</title>
7771 Type-7 sort is an extension to the Bib-1 based RPN query where the
7772 sort specification is embedded as an Attribute-Plus-Term.
7775 The objectives for introducing Type-7 sorting is that it allows
7776 a client to perform sorting even if it does not implement/support
7777 Z39.50 sort. Virtually all Z39.50 client software supports
7778 RPN queries. It also may improve performance because the sort
7779 critieria is specified along with the search query.
7782 The sort is triggered by the presence of type 7 and the value of type 7
7784 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7787 The value for type 7 is 1 for ascending and 2 for descending.
7789 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7792 only the generic part is handled. If generic sortKey is of type
7793 sortField, then attribute type 1 is present and the value is
7794 sortField (InternationalString). If generic sortKey is of type
7795 sortAttributes, then the attributes in list is used . generic sortKey
7796 of type elementSpec is not supported.
7799 The term in the sorting Attribute-Plus-Term combo should hold
7800 an integer. The value is 0 for primary sorting criteria, 1 for second
7806 <title>Facets</title>
7808 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7811 Like Type-1/RPN, YAZ supports a string notation for specifying
7812 facets. For the API this is performed by
7813 <function>yaz_pqf_parse_facet_list</function>.
7816 For ZOOM C the facets are given by option "facets"
7817 For yaz-client it is used for the facets command.
7820 The grammar of this specification is as follows:
7822 facet-spec ::= facet-list
7824 facet-list ::= facet-list ',' attr-spec | attr-spec
7826 attr-spec ::= attr-spec '@attr' string | '@attr' string
7829 The notation is inspired by PQF. The string following '@attr'
7830 may not include blanks and is of the form
7831 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7832 where <replaceable>type</replaceable> is an integer and
7833 <replaceable>value</replaceable> is a string or an integer.
7836 The Facets specification is not Bib-1. The following types apply:
7838 <table id="facet.attributes">
7839 <title>Facet attributes</title>
7841 <colspec colwidth="2*" colname="type"></colspec>
7842 <colspec colwidth="9*" colname="description"></colspec>
7846 <entry>Description</entry>
7853 Field-name. This is often a string, eg "Author", "Year", etc.
7859 Sort order. Value should be an integer.
7860 Value 0: count descending (frequency). Value 1: alpha ascending.
7866 Number of terms requested.
7881 <title>The ODR Module</title>
7882 <sect1 id="odr.introduction">
7883 <title>Introduction</title>
7885 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7886 to isolate &odr; from the rest of the package - specifically from the
7887 transport interface. &odr; may be used in any context where basic
7888 ASN.1/BER representations are used.
7891 If you are only interested in writing a Z39.50 implementation based on
7892 the PDUs that are already provided with &yaz;, you only need to concern
7893 yourself with the section on managing ODR streams
7894 (<xref linkend="odr.use"/>). Only if you need to
7895 implement ASN.1 beyond that which has been provided, should you
7896 worry about the second half of the documentation
7897 (<xref linkend="odr.programming"/>).
7898 If you use one of the higher-level interfaces, you can skip this
7902 This is important, so we'll repeat it for emphasis: <emphasis>You do
7903 not need to read <xref linkend="odr.programming"/>
7904 to implement Z39.50 with &yaz;.</emphasis>
7907 If you need a part of the protocol that isn't already in &yaz;, you
7908 should contact the authors before going to work on it yourself: We
7909 might already be working on it. Conversely, if you implement a useful
7910 part of the protocol before us, we'd be happy to include it in a
7914 <sect1 id="odr.use">
7915 <title>Using ODR</title>
7916 <sect2 id="odr.streams">
7917 <title>ODR Streams</title>
7919 Conceptually, the ODR stream is the source of encoded data in the
7920 decoding mode; when encoding, it is the receptacle for the encoded
7921 data. Before you can use an ODR stream it must be allocated. This is
7922 done with the function
7925 ODR odr_createmem(int direction);
7928 The <function>odr_createmem()</function> function takes as argument one
7929 of three manifest constants: <literal>ODR_ENCODE</literal>,
7930 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7931 An &odr; stream can be in only one mode - it is not possible to change
7932 its mode once it's selected. Typically, your program will allocate
7933 at least two ODR streams - one for decoding, and one for encoding.
7936 When you're done with the stream, you can use
7939 void odr_destroy(ODR o);
7942 to release the resources allocated for the stream.
7945 <sect2 id="odr.memory.management">
7946 <title id="memory">Memory Management</title>
7948 Two forms of memory management take place in the &odr; system. The first
7949 one, which has to do with allocating little bits of memory (sometimes
7950 quite large bits of memory, actually) when a protocol package is
7951 decoded, and turned into a complex of interlinked structures. This
7952 section deals with this system, and how you can use it for your own
7953 purposes. The next section deals with the memory management which is
7954 required when encoding data - to make sure that a large enough buffer is
7955 available to hold the fully encoded PDU.
7958 The &odr; module has its own memory management system, which is
7959 used whenever memory is required. Specifically, it is used to allocate
7960 space for data when decoding incoming PDUs. You can use the memory
7961 system for your own purposes, by using the function
7964 void *odr_malloc(ODR o, size_t size);
7967 You can't use the normal <function>free(2)</function> routine to free
7968 memory allocated by this function, and &odr; doesn't provide a parallel
7969 function. Instead, you can call
7972 void odr_reset(ODR o);
7975 when you are done with the
7976 memory: Everything allocated since the last call to
7977 <function>odr_reset()</function> is released.
7978 The <function>odr_reset()</function> call is also required to clear
7979 up an error condition on a stream.
7985 size_t odr_total(ODR o);
7988 returns the number of bytes allocated on the stream since the last call to
7989 <function>odr_reset()</function>.
7992 The memory subsystem of &odr; is fairly efficient at allocating and
7993 releasing little bits of memory. Rather than managing the individual,
7994 small bits of space, the system maintains a free-list of larger chunks
7995 of memory, which are handed out in small bits. This scheme is
7996 generally known as a <emphasis>nibble memory</emphasis> system.
7997 It is very useful for maintaining short-lived constructions such
8001 If you want to retain a bit of memory beyond the next call to
8002 <function>odr_reset()</function>, you can use the function
8005 ODR_MEM odr_extract_mem(ODR o);
8008 This function will give you control of the memory recently allocated
8009 on the ODR stream. The memory will live (past calls to
8010 <function>odr_reset()</function>), until you call the function
8013 void odr_release_mem(ODR_MEM p);
8016 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
8017 referencing the memory block for you until you want to release it.
8020 You can use <function>odr_extract_mem()</function> repeatedly between
8021 allocating data, to retain individual control of separate chunks of data.
8024 <sect2 id="odr.encoding.and.decoding">
8025 <title>Encoding and Decoding Data</title>
8027 When encoding data, the ODR stream will write the encoded octet string
8028 in an internal buffer. To retrieve the data, use the function
8031 char *odr_getbuf(ODR o, int *len, int *size);
8034 The integer pointed to by len is set to the length of the encoded
8035 data, and a pointer to that data is returned. <literal>*size</literal>
8036 is set to the size of the buffer (unless <literal>size</literal> is null,
8037 signaling that you are not interested in the size). The next call to
8038 a primitive function using the same &odr; stream will overwrite the
8039 data, unless a different buffer has been supplied using the call
8042 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8045 which sets the encoding (or decoding) buffer used by
8046 <literal>o</literal> to <literal>buf</literal>, using the length
8047 <literal>len</literal>.
8048 Before a call to an encoding function, you can use
8049 <function>odr_setbuf()</function> to provide the stream with an encoding
8050 buffer of sufficient size (length). The <literal>can_grow</literal>
8051 parameter tells the encoding &odr; stream whether it is allowed to use
8052 <function>realloc(2)</function> to increase the size of the buffer when
8053 necessary. The default condition of a new encoding stream is equivalent
8054 to the results of calling
8057 odr_setbuf(stream, 0, 0, 1);
8060 In this case, the stream will allocate and reallocate memory as
8061 necessary. The stream reallocates memory by repeatedly doubling the
8062 size of the buffer - the result is that the buffer will typically
8063 reach its maximum, working size with only a small number of reallocation
8064 operations. The memory is freed by the stream when the latter is destroyed,
8065 unless it was assigned by the user with the <literal>can_grow</literal>
8066 parameter set to zero (in this case, you are expected to retain
8067 control of the memory yourself).
8070 To assume full control of an encoded buffer, you must first call
8071 <function>odr_getbuf()</function> to fetch the buffer and its length.
8072 Next, you should call <function>odr_setbuf()</function> to provide a
8073 different buffer (or a null pointer) to the stream. In the simplest
8074 case, you will reuse the same buffer over and over again, and you
8075 will just need to call <function>odr_getbuf()</function> after each
8076 encoding operation to get the length and address of the buffer.
8077 Note that the stream may reallocate the buffer during an encoding
8078 operation, so it is necessary to retrieve the correct address after
8079 each encoding operation.
8082 It is important to realize that the ODR stream will not release this
8083 memory when you call <function>odr_reset()</function>: It will
8084 merely update its internal pointers to prepare for the encoding of a
8086 When the stream is released by the <function>odr_destroy()</function>
8087 function, the memory given to it by <function>odr_setbuf</function> will
8088 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
8089 parameter to <function>odr_setbuf()</function> was nonzero. The
8090 <literal>can_grow</literal> parameter, in other words, is a way of
8091 signaling who is to own the buffer, you or the ODR stream. If you never call
8092 <function>odr_setbuf()</function> on your encoding stream, which is
8093 typically the case, the buffer allocated by the stream will belong to
8094 the stream by default.
8097 When you wish to decode data, you should first call
8098 <function>odr_setbuf()</function>, to tell the decoding stream
8099 where to find the encoded data, and how long the buffer is
8100 (the <literal>can_grow</literal> parameter is ignored by a decoding
8101 stream). After this, you can call the function corresponding to the
8102 data you wish to decode (eg, <function>odr_integer()</function> odr
8103 <function>z_APDU()</function>).
8105 <example id="example.odr.encoding.and.decoding.functions">
8106 <title>Encoding and decoding functions</title>
8108 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8110 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
8114 If the data is absent (or doesn't match the tag corresponding to
8115 the type), the return value will be either 0 or 1 depending on the
8116 <literal>optional</literal> flag. If <literal>optional</literal>
8117 is 0 and the data is absent, an error flag will be raised in the
8118 stream, and you'll need to call <function>odr_reset()</function> before
8119 you can use the stream again. If <literal>optional</literal> is
8120 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
8121 <literal>p</literal> will be set to the null value, and the function
8123 The <literal>name</literal> argument is used to pretty-print the
8124 tag in question. It may be set to <literal>NULL</literal> if
8125 pretty-printing is not desired.
8128 If the data value is found where it's expected, the pointer
8129 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
8130 will be set to point to the decoded type.
8131 The space for the type will be allocated and owned by the &odr;
8132 stream, and it will live until you call
8133 <function>odr_reset()</function> on the stream. You cannot use
8134 <function>free(2)</function> to release the memory.
8135 You can decode several data elements (by repeated calls to
8136 <function>odr_setbuf()</function> and your decoding function), and
8137 new memory will be allocated each time. When you do call
8138 <function>odr_reset()</function>, everything decoded since the
8139 last call to <function>odr_reset()</function> will be released.
8141 <example id="example.odr.encoding.of.integer">
8142 <title>Encoding and decoding of an integer</title>
8144 The use of the double indirection can be a little confusing at first
8145 (its purpose will become clear later on, hopefully),
8146 so an example is in order. We'll encode an integer value, and
8147 immediately decode it again using a different stream. A useless, but
8148 informative operation.
8150 <programlisting><![CDATA[
8151 void do_nothing_useful(Odr_int value)
8154 Odr_int *valp, *resvalp;
8158 /* allocate streams */
8159 if (!(encode = odr_createmem(ODR_ENCODE)))
8161 if (!(decode = odr_createmem(ODR_DECODE)))
8165 if (odr_integer(encode, &valp, 0, 0) == 0)
8167 printf("encoding went bad\n");
8170 bufferp = odr_getbuf(encode, &len, 0);
8171 printf("length of encoded data is %d\n", len);
8173 /* now let's decode the thing again */
8174 odr_setbuf(decode, bufferp, len, 0);
8175 if (odr_integer(decode, &resvalp, 0, 0) == 0)
8177 printf("decoding went bad\n");
8180 /* ODR_INT_PRINTF format for printf (such as %d) */
8181 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
8184 odr_destroy(encode);
8185 odr_destroy(decode);
8190 This looks like a lot of work, offhand. In practice, the &odr; streams
8191 will typically be allocated once, in the beginning of your program
8192 (or at the beginning of a new network session), and the encoding
8193 and decoding will only take place in a few, isolated places in your
8194 program, so the overhead is quite manageable.
8198 <sect2 id="odr.printing">
8199 <title>Printing</title>
8201 When an ODR stream is created of type <literal>ODR_PRINT</literal>
8202 the ODR module will print the contents of a PDU in a readable format.
8203 By default output is written to the <literal>stderr</literal> stream.
8204 This behavior can be changed, however, by calling the function
8206 odr_setprint(ODR o, FILE *file);
8208 before encoders or decoders are being invoked.
8209 It is also possible to direct the output to a buffer (of indeed
8210 another file), by using the more generic mechanism:
8212 void odr_set_stream(ODR o, void *handle,
8213 void (*stream_write)(ODR o, void *handle, int type,
8214 const char *buf, int len),
8215 void (*stream_close)(void *handle));
8217 Here the user provides an opaque handle and two handlers,
8218 <replaceable>stream_write</replaceable> for writing,
8219 and <replaceable>stream_close</replaceable> which is supposed
8220 to close/free resources associated with handle.
8221 The <replaceable>stream_close</replaceable> handler is optional and
8222 if NULL for the function is provided, it will not be invoked.
8223 The <replaceable>stream_write</replaceable> takes the ODR handle
8224 as parameter, the user defined handle, a type
8225 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8226 which indicates the type of contents is being written.
8229 Another utility useful for diagnostics (error handling) or as
8230 part of the printing facilities is:
8232 const char **odr_get_element_path(ODR o);
8234 which returns a list of current elements that ODR deals with at the
8235 moment. For the returned array, say <literal>ar</literal>,
8236 <literal>ar[0]</literal> is the top level element,
8237 <literal>ar[n]</literal> is the last. The last element has the
8238 property that <literal>ar[n+1] == NULL</literal>.
8240 <example id="example.odr.element.path.record">
8241 <title>Element Path for record</title>
8243 For a database record part of a PresentResponse the
8244 array returned by <function>odr_get_element</function>
8245 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8246 unnamed constructions.
8250 <sect2 id="odr.diagnostics">
8251 <title>Diagnostics</title>
8253 The encoding/decoding functions all return 0 when an error occurs.
8254 Until you call <function>odr_reset()</function>, you cannot use the
8255 stream again, and any function called will immediately return 0.
8258 To provide information to the programmer or administrator, the function
8261 void odr_perror(ODR o, char *message);
8264 is provided, which prints the <literal>message</literal> argument to
8265 <literal>stderr</literal> along with an error message from the stream.
8268 You can also use the function
8271 int odr_geterror(ODR o);
8274 to get the current error number from the screen. The number will be
8275 one of these constants:
8277 <table frame="top" id="odr.error.codes">
8278 <title>ODR Error codes</title>
8283 <entry>Description</entry>
8288 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8291 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8292 The standard diagnostic variable <literal>errno</literal> should be
8293 examined to determine the actual error.</entry>
8296 <entry>OSPACE</entry><entry>No more space for encoding.
8297 This will only occur when the user has explicitly provided a
8298 buffer for an encoding stream without allowing the system to
8299 allocate more space.</entry>
8302 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8303 required data element was missing during encoding or decoding.</entry>
8306 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8307 found during decoding.</entry>
8310 <entry>OOTHER</entry><entry>Other error. This is typically an
8311 indication of misuse of the &odr; system by the programmer, and also
8312 that the diagnostic system isn't as good as it should be, yet.</entry>
8318 The character string array
8324 can be indexed by the error code to obtain a human-readable
8325 representation of the problem.
8328 <sect2 id="odr.summary.and.synopsis">
8329 <title>Summary and Synopsis</title>
8331 #include <yaz/odr.h>
8333 ODR odr_createmem(int direction);
8335 void odr_destroy(ODR o);
8337 void odr_reset(ODR o);
8339 char *odr_getbuf(ODR o, int *len, int *size);
8341 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8343 void *odr_malloc(ODR o, int size);
8345 NMEM odr_extract_mem(ODR o);
8347 int odr_geterror(ODR o);
8349 void odr_perror(ODR o, const char *message);
8351 extern char *odr_errlist[];
8355 <sect1 id="odr.programming">
8356 <title>Programming with ODR</title>
8358 The API of &odr; is designed to reflect the structure of ASN.1, rather
8359 than BER itself. Future releases may be able to represent data in
8360 other external forms.
8364 There is an ASN.1 tutorial available at
8365 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8366 This site also has standards for ASN.1 (X.680) and BER (X.690)
8367 <ulink url="&url.asn.1.standards;">online</ulink>.
8371 The ODR interface is based loosely on that of the Sun Microsystems
8373 Specifically, each function which corresponds to an ASN.1 primitive
8374 type has a dual function. Depending on the settings of the ODR
8375 stream which is supplied as a parameter, the function may be used
8376 either to encode or decode data. The functions that can be built
8377 using these primitive functions, to represent more complex data types,
8378 share this quality. The result is that you only have to enter the
8379 definition for a type once - and you have the functionality of encoding,
8380 decoding (and pretty-printing) all in one unit.
8381 The resulting C source code is quite compact, and is a pretty
8382 straightforward representation of the source ASN.1 specification.
8385 In many cases, the model of the XDR functions works quite well in this
8387 In others, it is less elegant. Most of the hassle comes from the optional
8388 SEQUENCE members which don't exist in XDR.
8390 <sect2 id="odr.primitive.asn1.types">
8391 <title>The Primitive ASN.1 Types</title>
8393 ASN.1 defines a number of primitive types (many of which correspond
8394 roughly to primitive types in structured programming languages, such as C).
8396 <sect3 id="odr.integer">
8397 <title>INTEGER</title>
8399 The &odr; function for encoding or decoding (or printing) the ASN.1
8400 INTEGER type looks like this:
8403 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8406 The <literal>Odr_int</literal> is just a simple integer.
8409 This form is typical of the primitive &odr; functions. They are named
8410 after the type of data that they encode or decode. They take an &odr;
8411 stream, an indirect reference to the type in question, and an
8412 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8413 of ASN.1) as parameters. They all return an integer value of either one
8415 When you use the primitive functions to construct encoders for complex
8416 types of your own, you should follow this model as well. This
8417 ensures that your new types can be reused as elements in yet more
8421 The <literal>o</literal> parameter should obviously refer to a properly
8422 initialized &odr; stream of the right type (encoding/decoding/printing)
8423 for the operation that you wish to perform.
8426 When encoding or printing, the function first looks at
8427 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8428 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8429 the data element is absent. If the <literal>optional</literal> parameter
8430 is nonzero, the function will return one (signifying success) without
8431 any further processing. If the <literal>optional</literal> is zero, an
8432 internal error flag is set in the &odr; stream, and the function will
8433 return 0. No further operations can be carried out on the stream without
8434 a call to the function <function>odr_reset()</function>.
8437 If <literal>*p</literal> is not a null pointer, it is expected to
8438 point to an instance of the data type. The data will be subjected to
8439 the encoding rules, and the result will be placed in the buffer held
8440 by the &odr; stream.
8443 The other ASN.1 primitives have similar functions that operate in
8447 <sect3 id="odr.boolean">
8448 <title>BOOLEAN</title>
8450 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8453 <sect3 id="odr.real">
8459 <sect3 id="odr.null">
8462 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8465 In this case, the value of **p is not important. If <literal>*p</literal>
8466 is different from the null pointer, the null value is present, otherwise
8470 <sect3 id="odr.octet.string">
8471 <title>OCTET STRING</title>
8473 typedef struct odr_oct
8479 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8483 The <literal>buf</literal> field should point to the character array
8484 that holds the octetstring. The <literal>len</literal> field holds the
8486 The character array need not be null terminated.
8489 To make things a little easier, an alternative is given for string
8490 types that are not expected to contain embedded NULL characters (eg.
8494 int odr_cstring(ODR o, char **p, int optional, const char *name);
8497 Which encoded or decodes between OCTETSTRING representations and
8498 null-terminates C strings.
8501 Functions are provided for the derived string types, eg:
8504 int odr_visiblestring(ODR o, char **p, int optional,
8508 <sect3 id="odr.bit.string">
8509 <title>BIT STRING</title>
8511 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8515 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8516 holding relatively brief bit strings, eg. for options fields, etc.
8517 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8518 gives the maximum possible number of bits.
8521 A set of macros are provided for manipulating the
8522 <literal>Odr_bitmask</literal> type:
8525 void ODR_MASK_ZERO(Odr_bitmask *b);
8527 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8529 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8531 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8534 The functions are modeled after the manipulation functions that
8535 accompany the <literal>fd_set</literal> type used by the
8536 <function>select(2)</function> call.
8537 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8538 new bitmask, to initialize the bits to zero.
8541 <sect3 id="odr.object.identifier">
8542 <title>OBJECT IDENTIFIER</title>
8544 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8547 The C OID representation is simply an array of integers, terminated by
8548 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8549 the <literal>short</literal> type).
8550 We suggest that you use the OID database module (see
8551 <xref linkend="tools.oid.database"/>) to handle object identifiers
8552 in your application.
8556 <sect2 id="odr.tagging.primitive.types">
8557 <title>Tagging Primitive Types</title>
8559 The simplest way of tagging a type is to use the
8560 <function>odr_implicit_tag()</function> or
8561 <function>odr_explicit_tag()</function> macros:
8564 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8565 int optional, const char *name);
8567 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8568 int optional, const char *name);
8571 To create a type derived from the integer type by implicit tagging, you
8575 MyInt ::= [210] IMPLICIT INTEGER
8578 In the &odr; system, this would be written like:
8581 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8583 return odr_implicit_tag(o, odr_integer, p,
8584 ODR_CONTEXT, 210, optional, name);
8588 The function <function>myInt()</function> can then be used like any of
8589 the primitive functions provided by &odr;. Note that the behavior of
8590 <function>odr_explicit_tag()</function>
8591 and <function>odr_implicit_tag()</function> macros
8592 act exactly the same as the functions they are applied to - they
8593 respond to error conditions, etc, in the same manner - they
8594 simply have three extra parameters. The class parameter may
8595 take one of the values: <literal>ODR_CONTEXT</literal>,
8596 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8597 <literal>/ODR_APPLICATION</literal>.
8600 <sect2 id="odr.constructed.types">
8601 <title>Constructed Types</title>
8603 Constructed types are created by combining primitive types. The
8604 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8605 (although adding the rest of the container types should be simple
8606 enough, if the need arises).
8609 For implementing SEQUENCEs, the functions
8612 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8613 int odr_sequence_end(ODR o);
8619 The <function>odr_sequence_begin()</function> function should be
8620 called in the beginning of a function that implements a SEQUENCE type.
8621 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8622 you're implementing), and the <literal>size</literal> of the type
8623 (typically a C structure). On encoding, it returns 1 if
8624 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8625 parameter is ignored. On decoding, it returns 1 if the type is found in
8626 the data stream. <literal>size</literal> bytes of memory are allocated,
8627 and <literal>*p</literal> is set to point to this space.
8628 <function>odr_sequence_end()</function> is called at the end of the
8629 complex function. Assume that a type is defined like this:
8632 MySequence ::= SEQUENCE {
8634 boolval BOOLEAN OPTIONAL
8638 The corresponding &odr; encoder/decoder function and the associated data
8639 structures could be written like this:
8642 typedef struct MySequence
8648 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8650 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8651 return optional && odr_ok(o);
8653 odr_integer(o, &(*p)->intval, 0, "intval") &&
8654 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8655 odr_sequence_end(o);
8659 Note the 1 in the call to <function>odr_bool()</function>, to mark
8660 that the sequence member is optional.
8661 If either of the member types had been tagged, the macros
8662 <function>odr_implicit_tag()</function> or
8663 <function>odr_explicit_tag()</function>
8664 could have been used.
8665 The new function can be used exactly like the standard functions provided
8666 with &odr;. It will encode, decode or pretty-print a data value of the
8667 <literal>MySequence</literal> type. We like to name types with an
8668 initial capital, as done in ASN.1 definitions, and to name the
8669 corresponding function with the first character of the name in lower case.
8670 You could, of course, name your structures, types, and functions any way
8671 you please - as long as you're consistent, and your code is easily readable.
8672 <literal>odr_ok</literal> is just that - a predicate that returns the
8673 state of the stream. It is used to ensure that the behavior of the new
8674 type is compatible with the interface of the primitive types.
8677 <sect2 id="odr.tagging.constructed.types">
8678 <title>Tagging Constructed Types</title>
8681 See <xref linkend="odr.tagging.primitive.types"/> for information
8682 on how to tag the primitive types, as well as types that are
8686 <sect3 id="odr.implicit.tagging">
8687 <title>Implicit Tagging</title>
8689 Assume the type above had been defined as
8692 MySequence ::= [10] IMPLICIT SEQUENCE {
8694 boolval BOOLEAN OPTIONAL
8698 You would implement this in &odr; by calling the function
8701 int odr_implicit_settag(ODR o, int class, int tag);
8704 which overrides the tag of the type immediately following it. The
8705 macro <function>odr_implicit_tag()</function> works by calling
8706 <function>odr_implicit_settag()</function> immediately
8707 before calling the function pointer argument.
8708 Your type function could look like this:
8711 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8713 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8714 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8715 return optional && odr_ok(o);
8717 odr_integer(o, &(*p)->intval, 0, "intval") &&
8718 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8719 odr_sequence_end(o);
8723 The definition of the structure <literal>MySequence</literal> would be
8727 <sect3 id="odr.explicit.tagging">
8728 <title>Explicit Tagging</title>
8730 Explicit tagging of constructed types is a little more complicated,
8731 since you are in effect adding a level of construction to the data.
8734 Assume the definition:
8737 MySequence ::= [10] IMPLICIT SEQUENCE {
8739 boolval BOOLEAN OPTIONAL
8743 Since the new type has an extra level of construction, two new functions
8744 are needed to encapsulate the base type:
8747 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8750 int odr_constructed_end(ODR o);
8753 Assume that the IMPLICIT in the type definition above were replaced
8754 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8755 would be equivalent). The structure definition would look the same,
8756 but the function would look like this:
8759 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8761 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8762 return optional && odr_ok(o);
8763 if (o->direction == ODR_DECODE)
8764 *p = odr_malloc(o, sizeof(**p));
8765 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8767 *p = 0; /* this is almost certainly a protocol error */
8771 odr_integer(o, &(*p)->intval, 0, "intval") &&
8772 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8773 odr_sequence_end(o) &&
8774 odr_constructed_end(o);
8778 Notice that the interface here gets kind of nasty. The reason is
8779 simple: Explicitly tagged, constructed types are fairly rare in
8780 the protocols that we care about, so the
8781 esthetic annoyance (not to mention the dangers of a cluttered
8782 interface) is less than the time that would be required to develop a
8783 better interface. Nevertheless, it is far from satisfying, and it's a
8784 point that will be worked on in the future. One option for you would
8785 be to simply apply the <function>odr_explicit_tag()</function> macro to
8786 the first function, and not
8787 have to worry about <function>odr_constructed_*</function> yourself.
8788 Incidentally, as you might have guessed, the
8789 <function>odr_sequence_</function> functions are themselves
8790 implemented using the <function>/odr_constructed_</function> functions.
8794 <sect2 id="odr.sequence.of">
8795 <title>SEQUENCE OF</title>
8797 To handle sequences (arrays) of a specific type, the function
8800 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8801 void *p, int *num, const char *name);
8804 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8805 function of the type. <literal>p</literal> is a pointer to an array of
8806 pointers to your type. <literal>num</literal> is the number of elements
8813 MyArray ::= SEQUENCE OF INTEGER
8816 The C representation might be
8819 typedef struct MyArray
8826 And the function might look like
8829 int myArray(ODR o, MyArray **p, int optional, const char *name)
8831 if (o->direction == ODR_DECODE)
8832 *p = odr_malloc(o, sizeof(**p));
8833 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8834 &(*p)->num_elements, name))
8837 return optional && odr_ok(o);
8841 <sect2 id="odr.choice.types">
8842 <title>CHOICE Types</title>
8844 The choice type is used fairly often in some ASN.1 definitions, so
8845 some work has gone into streamlining its interface.
8848 CHOICE types are handled by the function:
8851 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8855 The <literal>arm</literal> array is used to describe each of the possible
8856 types that the CHOICE type may assume. Internally in your application,
8857 the CHOICE type is represented as a discriminated union. That is, a
8858 C union accompanied by an integer (or enum) identifying the active
8860 <literal>whichp</literal> is a pointer to the union discriminator.
8861 When encoding, it is examined to determine the current type.
8862 When decoding, it is set to reference the type that was found in
8866 The Odr_arm type is defined thus:
8869 typedef struct odr_arm
8880 The interpretation of the fields are:
8884 <term>tagmode</term>
8885 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8886 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8887 to mark no tagging.</para></listitem>
8891 <listitem><para>The value of the discriminator that corresponds to
8892 this CHOICE element. Typically, it will be a #defined constant, or
8893 an enum member.</para></listitem>
8897 <listitem><para>A pointer to a function that implements the type of
8898 the CHOICE member. It may be either a standard &odr; type or a type
8899 defined by yourself.</para></listitem>
8903 <listitem><para>Name of tag.</para></listitem>
8907 A handy way to prepare the array for use by the
8908 <function>odr_choice()</function> function is to
8909 define it as a static, initialized array in the beginning of your
8910 decoding/encoding function. Assume the type definition:
8913 MyChoice ::= CHOICE {
8915 tagged [99] IMPLICIT INTEGER,
8920 Your C type might look like
8923 typedef struct MyChoice
8940 And your function could look like this:
8943 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8945 static Odr_arm arm[] =
8947 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8948 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8950 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8954 if (o->direction == ODR_DECODE)
8955 *p = odr_malloc(o, sizeof(**p);
8957 return optional && odr_ok(o);
8959 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8962 return optional && odr_ok(o);
8966 In some cases (say, a non-optional choice which is a member of a
8967 sequence), you can "embed" the union and its discriminator in the
8968 structure belonging to the enclosing type, and you won't need to
8969 fiddle with memory allocation to create a separate structure to
8970 wrap the discriminator and union.
8973 The corresponding function is somewhat nicer in the Sun XDR interface.
8974 Most of the complexity of this interface comes from the possibility of
8975 declaring sequence elements (including CHOICEs) optional.
8978 The ASN.1 specifications naturally requires that each member of a
8979 CHOICE have a distinct tag, so they can be told apart on decoding.
8980 Sometimes it can be useful to define a CHOICE that has multiple types
8981 that share the same tag. You'll need some other mechanism, perhaps
8982 keyed to the context of the CHOICE type. In effect, we would like to
8983 introduce a level of context-sensitiveness to our ASN.1 specification.
8984 When encoding an internal representation, we have no problem, as long
8985 as each CHOICE member has a distinct discriminator value. For
8986 decoding, we need a way to tell the choice function to look for a
8987 specific arm of the table. The function
8990 void odr_choice_bias(ODR o, int what);
8993 provides this functionality. When called, it leaves a notice for the next
8994 call to <function>odr_choice()</function> to be called on the decoding
8995 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8996 a <literal>which</literal> field equal to <literal>what</literal>
9000 The most important application (perhaps the only one, really) is in
9001 the definition of application-specific EXTERNAL encoders/decoders
9002 which will automatically decode an ANY member given the direct or
9007 <sect1 id="odr.debugging">
9008 <title>Debugging</title>
9010 The protocol modules are suffering somewhat from a lack of diagnostic
9011 tools at the moment. Specifically ways to pretty-print PDUs that
9012 aren't recognized by the system. We'll include something to this end
9013 in a not-too-distant release. In the meantime, what we do when we get
9014 packages we don't understand is to compile the ODR module with
9015 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
9016 information as it processes data units. With this output and the
9017 protocol specification (Z39.50), it is generally fairly easy to see
9022 <chapter id="comstack">
9023 <title>The COMSTACK Module</title>
9024 <sect1 id="comstack.synopsis">
9025 <title>Synopsis (blocking mode)</title>
9026 <programlisting><![CDATA[
9029 int size = 0, length_incoming;
9030 char server_address_str[] = "localhost:9999";
9031 void *server_address_ip;
9034 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
9035 int protocol_package_length = strlen(protocol_package);
9037 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
9039 perror("cs_create"); /* use perror() here since we have no stack yet */
9043 server_address_ip = cs_straddr(stack, server_address_str);
9044 if (!server_address_ip) {
9045 fprintf(stderr, "cs_straddr: address could not be resolved\n");
9049 status = cs_connect(stack, server_address_ip);
9051 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
9055 status = cs_rcvconnect(stack);
9057 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
9061 status = cs_put(stack, protocol_package, protocol_package_length);
9063 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
9067 /* Now get a response */
9068 length_incoming = cs_get(stack, &buf, &size);
9069 if (!length_incoming) {
9070 fprintf(stderr, "Connection closed\n");
9072 } else if (length_incoming < 0) {
9073 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
9078 fwrite(buf, length_incoming, 1, stdout);
9089 <sect1 id="comstack.introduction">
9090 <title>Introduction</title>
9093 subsystem provides a transparent interface to different types of transport
9094 stacks for the exchange of BER-encoded data and HTTP packets.
9095 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
9096 experimental SSL stack are supported, but others may be added in time.
9097 The philosophy of the
9098 module is to provide a simple interface by hiding unused options and
9099 facilities of the underlying libraries. This is always done at the risk
9100 of losing generality, and it may prove that the interface will need
9105 There hasn't been interest in the XTImOSI stack for some years.
9106 Therefore, it is no longer supported.
9110 The interface is implemented in such a fashion that only the
9111 sub-layers constructed to the transport methods that you wish to
9112 use in your application are linked in.
9115 You will note that even though simplicity was a goal in the design,
9116 the interface is still orders of magnitudes more complex than the
9117 transport systems found in many other packages. One reason is that
9118 the interface needs to support the somewhat different requirements of
9119 the different lower-layer communications stacks; another important
9120 reason is that the interface seeks to provide a more or less
9121 industrial-strength approach to asynchronous event-handling.
9122 When no function is allowed to block, things get more complex -
9123 particularly on the server side.
9124 We urge you to have a look at the demonstration client and server
9125 provided with the package. They are meant to be easily readable and
9126 instructive, while still being at least moderately useful.
9129 <sect1 id="comstack.common">
9130 <title>Common Functions</title>
9131 <sect2 id="comstack.managing.endpoints">
9132 <title>Managing Endpoints</title>
9134 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9137 Creates an instance of the protocol stack - a communications endpoint.
9138 The <literal>type</literal> parameter determines the mode
9139 of communication. At present the following values are supported:
9143 <term><literal>tcpip_type</literal></term>
9144 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
9148 <term><literal>ssl_type</literal></term>
9149 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
9150 is experimental and is not fully implemented. If
9151 HTTP is used, this effectively is HTTPS.
9155 <term><literal>unix_type</literal></term>
9156 <listitem><para>Unix socket (unix only). Local Transfer via
9157 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
9158 <manvolnum>7</manvolnum></citerefentry>.
9163 The <function>cs_create</function> function returns a null-pointer
9164 if a system error occurs.
9165 The <literal>blocking</literal> parameter should be one if
9166 you wish the association to operate in blocking mode, zero otherwise.
9167 The <literal>protocol</literal> field should be
9168 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
9169 Protocol <literal>PROTO_SR</literal> is no longer supported.
9172 void cs_close(COMSTACK handle);
9175 Closes the connection (as elegantly as the lower layers will permit),
9176 and releases the resources pointed to by the
9177 <literal>handle</literal>
9179 <literal>handle</literal>
9180 should not be referenced again after this call.
9184 We really need a soft disconnect, don't we?
9188 <sect2 id="comstack.data.exchange">
9189 <title>Data Exchange</title>
9191 int cs_put(COMSTACK handle, char *buf, int len);
9194 Sends <literal>buf</literal> down the wire.
9195 In blocking mode, this function will return only when a full buffer has
9196 been written, or an error has occurred. In nonblocking mode, it's
9197 possible that the function will be unable to send the full buffer
9198 at once, which will be indicated by a return value of 1.
9199 The function will keep track of the number of octets already written; you
9200 should call it repeatedly with the same values of <literal>buf</literal>
9201 and <literal>len</literal>, until the buffer has been transmitted.
9202 When a full buffer has been sent, the function will return 0 for
9203 success. -1 indicates an error condition (see below).
9206 int cs_get(COMSTACK handle, char **buf, int *size);
9209 Receives a PDU or HTTP Response from the peer. Returns the number of
9211 In nonblocking mode, it is possible that not all of the packet can be
9212 read at once. In this case, the function returns 1. To simplify the
9213 interface, the function is
9214 responsible for managing the size of the buffer. It will be reallocated
9215 if necessary to contain large packages, and will sometimes be moved
9216 around internally by the subsystem when partial packages are read. Before
9218 <function>cs_get</function>
9219 for the fist time, the buffer can be initialized to the null pointer,
9220 and the length should also be set to 0 - cs_get will perform a
9221 <function>malloc(2)</function>
9222 on the buffer for you. When a full buffer has been read, the size of
9223 the package is returned (which will always be greater than 1). -1
9224 indicates an error condition.
9227 See also the <function>cs_more()</function> function below.
9230 int cs_more(COMSTACK handle);
9233 The <function>cs_more()</function> function should be used in conjunction
9234 with <function>cs_get</function> and
9235 <function>select(2)</function>.
9236 The <function>cs_get()</function> function will sometimes
9237 (notably in the TCP/IP mode) read more than a single protocol package
9238 off the network. When this happens, the extra package is stored
9239 by the subsystem. After calling <function>cs_get()</function>, and before
9240 waiting for more input, You should always call
9241 <function>cs_more()</function>
9242 to check if there's a full protocol package already read. If
9243 <function>cs_more()</function>
9245 <function>cs_get()</function>
9246 can be used to immediately fetch the new package. For the
9248 subsystem, the function should always return 0, but if you want your
9249 stuff to be protocol independent, you should use it.
9253 The <function>cs_more()</function>
9254 function is required because the RFC1729-method
9255 does not provide a way of separating individual PDUs, short of
9256 partially decoding the BER. Some other implementations will carefully
9257 nibble at the packet by calling
9258 <function>read(2)</function>
9259 several times. This was felt to be too inefficient (or at least
9260 clumsy) - hence the call for this extra function.
9264 int cs_look(COMSTACK handle);
9267 This function is useful when you're operating in nonblocking
9269 <function>select(2)</function>
9270 tells you there's something happening on the line. It returns one of
9271 the following values:
9275 <term>CS_NONE</term>
9277 No event is pending. The data found on the line was not a
9282 <term>CS_CONNECT</term>
9284 A response to your connect request has been received. Call
9285 <function>cs_rcvconnect</function>
9286 to process the event and to finalize the connection establishment.
9290 <term>CS_DISCON</term>
9292 The other side has closed the connection (or maybe sent a disconnect
9293 request - but do we care? Maybe later). Call
9294 <function>cs_close</function> to close your end of the association
9299 <term>CS_LISTEN</term>
9301 A connect request has been received.
9302 Call <function>cs_listen</function> to process the event.
9306 <term>CS_DATA</term>
9308 There's data to be found on the line.
9309 Call <function>cs_get</function> to get it.
9315 You should be aware that even if
9316 <function>cs_look()</function>
9317 tells you that there's an event event pending, the corresponding
9318 function may still return and tell you there was nothing to be found.
9319 This means that only part of a package was available for reading. The
9320 same event will show up again, when more data has arrived.
9324 int cs_fileno(COMSTACK h);
9327 Returns the file descriptor of the association. Use this when
9328 file-level operations on the endpoint are required
9329 (<function>select(2)</function> operations, specifically).
9333 <sect1 id="comstack.client">
9334 <title>Client Side</title>
9336 int cs_connect(COMSTACK handle, void *address);
9339 Initiate a connection with the target at <literal>address</literal>
9340 (more on addresses below). The function will return 0 on success, and 1 if
9341 the operation does not complete immediately (this will only
9342 happen on a nonblocking endpoint). In this case, use
9343 <function>cs_rcvconnect</function> to complete the operation,
9344 when <function>select(2)</function> or <function>poll(2)</function>
9345 reports input pending on the association.
9348 int cs_rcvconnect(COMSTACK handle);
9351 Complete a connect operation initiated by <function>cs_connect()</function>.
9352 It will return 0 on success; 1 if the operation has not yet completed (in
9353 this case, call the function again later); -1 if an error has occurred.
9356 <sect1 id="comstack.server">
9357 <title>Server Side</title>
9359 To establish a server under the <application>inetd</application>
9363 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9367 The <literal>socket</literal> parameter is an established socket (when
9368 your application is invoked from <application>inetd</application>, the
9369 socket will typically be 0.
9370 The following parameters are identical to the ones for
9371 <function>cs_create</function>.
9374 int cs_bind(COMSTACK handle, void *address, int mode)
9377 Binds a local address to the endpoint. Read about addresses below. The
9378 <literal>mode</literal> parameter should be either
9379 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9382 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9385 Call this to process incoming events on an endpoint that has been
9386 bound in listening mode. It will return 0 to indicate that the connect
9387 request has been received, 1 to signal a partial reception, and -1 to
9388 indicate an error condition.
9391 COMSTACK cs_accept(COMSTACK handle);
9394 This finalizes the server-side association establishment, after
9395 cs_listen has completed successfully. It returns a new connection
9396 endpoint, which represents the new association. The application will
9397 typically wish to fork off a process to handle the association at this
9398 point, and continue listen for new connections on the old
9399 <literal>handle</literal>.
9402 You can use the call
9405 const char *cs_addrstr(COMSTACK);
9408 on an established connection to retrieve the host-name of the remote host.
9412 You may need to use this function with some care if your
9413 name server service is slow or unreliable
9417 <sect1 id="comstack.addresses">
9418 <title>Addresses</title>
9420 The low-level format of the addresses are different depending on the
9421 mode of communication you have chosen. A function is provided by each
9422 of the lower layers to map a user-friendly string-form address to the
9423 binary form required by the lower layers.
9426 void *cs_straddr(COMSTACK handle, const char *str);
9429 The format for TCP/IP and SSL addresses is:
9432 <host> [ ':' <portnum> ]
9435 The <literal>hostname</literal> can be either a domain name or an
9436 IP address. The port number, if omitted, defaults to 210.
9439 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9440 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9441 IPV4 binding as well (bindv6only=0),
9442 The special hostname <literal>@4</literal> binds to
9443 <literal>INADDR_ANY</literal> (IPV4 only listener).
9444 The special hostname <literal>@6</literal> binds to
9445 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9448 For UNIX sockets, the format of an address is the socket filename.
9451 When a connection has been established, you can use
9454 const char *cs_addrstr(COMSTACK h);
9457 to retrieve the host name of the peer system. The function returns
9458 a pointer to a static area, which is overwritten on the next call
9462 A fairly recent addition to the &comstack; module is the utility
9466 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9469 which is just a wrapper for <function>cs_create</function> and
9470 <function>cs_straddr</function>. The <parameter>str</parameter>
9471 is similar to that described for <function>cs_straddr</function>
9472 but with a prefix denoting the &comstack; type. Prefixes supported
9473 are <literal>tcp:</literal>, <literal>unix:</literal> and
9474 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9475 If no prefix is given, then TCP/IP is used.
9476 The <parameter>blocking</parameter> is passed to
9477 function <function>cs_create</function>. The third parameter
9478 <parameter>vp</parameter> is a pointer to &comstack; stack type
9480 Parameter <parameter>vp</parameter> is reserved for future use.
9481 Set it to <literal>NULL</literal>.
9484 <sect1 id="comstack.ssl">
9488 void *cs_get_ssl(COMSTACK cs);
9490 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9491 is not of type SSL, NULL is returned.
9495 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9497 Sets SSL context for comstack. The parameter is expected to be of type
9498 <literal>SSL_CTX *</literal>. This function should be called just
9499 after comstack has been created (before connect, bind, etc).
9500 This function returns 1 for success; 0 for failure.
9504 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9506 Sets SSL certificate for comstack as a PEM file. This function
9507 returns 1 for success; 0 for failure.
9511 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9513 This function returns the peer certificate. If successful,
9514 <literal>*buf</literal> and <literal>*len</literal> holds
9515 X509 buffer and length respectively. Buffer should be freed
9516 with <literal>xfree</literal>. This function returns 1 for success;
9520 <sect1 id="comstack.diagnostics">
9521 <title>Diagnostics</title>
9523 All functions return -1 if an error occurs. Typically, the functions
9524 will return 0 on success, but the data exchange functions
9525 (<function>cs_get</function>, <function>cs_put</function>,
9526 <function>cs_more</function>) follow special rules. Consult their
9530 The error code for the COMSTACK can be retrieved using C macro
9531 <function>cs_errno</function> which will return one
9532 of the error codes <literal>CSYSERR</literal>,
9533 <literal>CSOUTSTATE</literal>,
9534 <literal>CSNODATA</literal>, ...
9537 int cs_errno(COMSTACK handle);
9540 You can the textual representation of the error code
9541 by using <function>cs_errmsg</function> - which
9542 works like <function>strerror(3)</function>
9545 const char *cs_errmsg(int n);
9548 It is also possible to get straight to the textual represenataion
9549 without the error code by using
9550 <function>cs_strerror</function>.
9553 const char *cs_strerror(COMSTACK h);
9556 <sect1 id="comstack.summary">
9557 <title>Summary and Synopsis</title>
9559 #include <yaz/comstack.h>
9561 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9562 #include <yaz/unix.h> /* this is for UNIX socket support */
9564 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9566 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9568 COMSTACK cs_create_host(const char *str, int blocking,
9571 int cs_bind(COMSTACK handle, int mode);
9573 int cs_connect(COMSTACK handle, void *address);
9575 int cs_rcvconnect(COMSTACK handle);
9577 int cs_listen(COMSTACK handle);
9579 COMSTACK cs_accept(COMSTACK handle);
9581 int cs_put(COMSTACK handle, char *buf, int len);
9583 int cs_get(COMSTACK handle, char **buf, int *size);
9585 int cs_more(COMSTACK handle);
9587 void cs_close(COMSTACK handle);
9589 int cs_look(COMSTACK handle);
9591 void *cs_straddr(COMSTACK handle, const char *str);
9593 const char *cs_addrstr(COMSTACK h);
9598 <chapter id="future">
9599 <title>Future Directions</title>
9601 We have a new and better version of the front-end server on the drawing
9602 board. Resources and external commitments will govern when we'll be
9603 able to do something real with it. Features should include greater
9604 flexibility, greater support for access/resource control, and easy
9605 support for Explain (possibly with Zebra as an extra database engine).
9608 &yaz; is a BER toolkit and as such should support all protocols
9609 out there based on that. We'd like to see running ILL applications.
9610 It shouldn't be that hard. Another thing that would be interesting is
9611 LDAP. Maybe a generic framework for doing IR using both LDAP and
9612 Z39.50 transparently.
9615 The SOAP implementation is incomplete. In the future we hope
9616 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9617 The authors of libxml2 are already working on XML Schema / RelaxNG
9618 compilers so this may not be too hard.
9621 It would be neat to have a proper module mechanism for the Generic
9622 Frontend Server so that backend would be dynamically
9623 loaded (as shared objects / DLLs).
9626 Other than that, &yaz; generally moves in the directions which appear to
9627 make the most people happy (including ourselves, as prime users of the
9628 software). If there's something you'd like to see in here, then drop
9629 us a note and let's see what we can come up with.
9632 <reference id="reference">
9633 <title>Reference</title>
9634 <partintro id="reference-introduction">
9636 The material in this chapter is drawn directly from the individual
9642 <appendix id="list-oids">
9643 <title>List of Object Identifiers</title>
9645 These is a list of object identifiers that are built into YAZ.
9649 <appendix id="bib1-diagnostics">
9650 <title>Bib-1 diagnostics</title>
9652 List of Bib-1 diagnostics that are known to YAZ.
9656 <appendix id="sru-diagnostics">
9657 <title>SRU diagnostics</title>
9659 List of SRU diagnostics that are known to YAZ.
9663 <appendix id="license">
9664 <title>License</title>
9665 <sect1 id="license.indexdata">
9666 <title>Index Data Copyright</title>
9668 Copyright © ©right-year; Index Data.
9671 All rights reserved.
9674 Redistribution and use in source and binary forms, with or without
9675 modification, are permitted provided that the following conditions are met:
9680 Redistributions of source code must retain the above copyright
9681 notice, this list of conditions and the following disclaimer.
9686 Redistributions in binary form must reproduce the above copyright
9687 notice, this list of conditions and the following disclaimer in the
9688 documentation and/or other materials provided with the distribution.
9693 Neither the name of Index Data nor the names of its contributors
9694 may be used to endorse or promote products derived from this
9695 software without specific prior written permission.
9700 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9701 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9702 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9703 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9704 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9705 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9706 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9707 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9708 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9709 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9714 <appendix id="indexdata">
9715 <title>About Index Data</title>
9717 Index Data is a consulting and software-development enterprise that
9718 specializes in library and information management systems. Our
9719 interests and expertise span a broad range of related fields, and one
9720 of our primary, long-term objectives is the development of a powerful
9721 information management
9722 system with open network interfaces and hyper-media capabilities.
9724 We make this software available free of charge, on a fairly unrestrictive
9725 license; as a service to the networking community, and to further the
9726 development of quality software for open network communication.
9728 We'll be happy to answer questions about the software, and about ourselves
9734 <street>Amagerfælledvej 56</street>
9735 <postcode>2300 Copenhagen S</postcode>
9736 <country>Denmark</country>
9737 Email <email>info@indexdata.dk</email>
9741 The Hacker's Jargon File has the following to say about the
9743 prefix "YA" in the name of a software product.
9747 Yet Another. adj. 1. Of your own work: A
9748 humorous allusion often used in titles to acknowledge that the
9749 topic is not original, though the content is. As in "Yet Another
9750 AI Group" or "Yet Another Simulated Annealing Algorithm".
9752 others' work: Describes something of which there are already far
9757 <appendix id="credits">
9758 <title>Credits</title>
9760 This appendix lists individuals that have contributed in the development
9761 of &yaz;. Some have contributed with code, while others have provided bug
9762 fixes or suggestions. If we're missing somebody, of if you, for
9763 whatever reason, don't like to be listed here, let us know.
9773 Morten Bøgeskov
9794 Mads Bondo Dydensborg
9803 Morten Garkier Hendriksen
9860 Tom André Øverland
9866 <!-- Keep this comment at the end of the file
9869 nxml-child-indent: 1