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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;">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 thie manual, so a quick walkthrough of the chapters
147 <xref linkend="installation"/> contains installation
148 instructions for &yaz;. You don't need reading 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 a read 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 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 is 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 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> 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 built 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 uset 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 it
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 it
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 have 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 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 demonstrates 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
1225 For Libxslt it is similar. We must ensure that compilation of
1226 Libxslt links against the already installed libxml2.
1229 cscript configure.js prefix=c:\libxslt-1.1.28.win32 iconv=no \
1230 lib=c:\libxmlt-2.9.2.win32\lib \
1231 include=c:\libxmlt-2.9.2.win32\include\libxml2
1241 ### Still to document:
1242 ZOOM_connection_errcode(c)
1243 ZOOM_connection_errmsg(c)
1244 ZOOM_connection_addinfo(c)
1245 ZOOM_connection_addinfo(c)
1246 ZOOM_connection_diagset(c);
1247 ZOOM_connection_save_apdu_wrbuf
1248 ZOOM_diag_str(error)
1249 ZOOM_resultset_record_immediate(s, pos)
1250 ZOOM_resultset_cache_reset(r)
1251 ZOOM_options_set_callback(opt, function, handle)
1252 ZOOM_options_create_with_parent2(parent1, parent2)
1253 ZOOM_options_getl(opt, name, len)
1254 ZOOM_options_setl(opt, name, value, len)
1255 ZOOM_options_get_bool(opt, name, defa)
1256 ZOOM_options_get_int(opt, name, defa)
1257 ZOOM_options_set_int(opt, name, value)
1262 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1263 an initiative started by Mike Taylor (Mike is from the UK, which
1264 explains the peculiar name of the model). The goal of &zoom; is to
1265 provide a common Z39.50 client API not bound to a particular
1266 programming language or toolkit.
1269 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1270 You can make SRU ZOOM connections by specifying scheme
1271 <literal>http://</literal> for the hostname for a connection.
1272 The dialect of SRU used is specified by the value of the
1273 connection's <literal>sru</literal> option, which may be SRU over
1274 HTTP GET (<literal>get</literal>),
1275 SRU over HTTP POST (<literal>post</literal>), (SRU over
1276 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1277 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1278 Using the facility for embedding options in target strings, a
1279 connection can be forced to use SRU rather the SRW (the default) by
1280 prefixing the target string with <literal>sru=get,</literal>, like this:
1281 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1284 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1285 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1286 HTTP based protocols.
1289 The lack of a simple Z39.50 client API for &yaz; has become more
1290 and more apparent over time. So when the first &zoom; specification
1292 an implementation for &yaz; was quickly developed. For the first time, it is
1293 now as easy (or easier!) to develop clients than servers with &yaz;. This
1294 chapter describes the &zoom; C binding. Before going further, please
1295 reconsider whether C is the right programming language for the job.
1296 There are other language bindings available for &yaz;, and still
1298 are in active development. See the
1299 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1303 In order to fully understand this chapter you should read and
1304 try the example programs <literal>zoomtst1.c</literal>,
1305 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1309 The C language misses features found in object oriented languages
1310 such as C++, Java, etc. For example, you'll have to manually,
1311 destroy all objects you create, even though you may think of them as
1312 temporary. Most objects has a <literal>_create</literal> - and a
1313 <literal>_destroy</literal> variant.
1314 All objects are in fact pointers to internal stuff, but you don't see
1315 that because of typedefs. All destroy methods should gracefully ignore a
1316 <literal>NULL</literal> pointer.
1319 In each of the sections below you'll find a sub section called
1320 protocol behavior, that describes how the API maps to the Z39.50
1323 <sect1 id="zoom-connections">
1324 <title>Connections</title>
1325 <para>The Connection object is a session with a target.
1328 #include <yaz/zoom.h>
1330 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1332 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1334 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1336 void ZOOM_connection_destroy(ZOOM_connection c);
1339 Connection objects are created with either function
1340 <function>ZOOM_connection_new</function> or
1341 <function>ZOOM_connection_create</function>.
1342 The former creates and automatically attempts to establish a network
1343 connection with the target. The latter doesn't establish
1344 a connection immediately, thus allowing you to specify options
1345 before establishing network connection using the function
1346 <function>ZOOM_connection_connect</function>.
1347 If the port number, <literal>portnum</literal>, is zero, the
1348 <literal>host</literal> is consulted for a port specification.
1349 If no port is given, 210 is used. A colon denotes the beginning of
1350 a port number in the host string. If the host string includes a
1351 slash, the following part specifies a database for the connection.
1354 You can prefix the host with a scheme followed by colon. The
1355 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1356 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1357 but can overridded to use SRU/post, SRW and the Solr protocol.
1360 You can prefix the scheme-qualified host-string with one or more
1362 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1363 sequences, each of which represents an option to be set into the
1364 connection structure <emphasis>before</emphasis> the
1365 protocol-level connection is forged and the initialization
1366 handshake takes place. This facility can be used to provide
1367 authentication credentials, as in host-strings such as:
1368 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1371 Connection objects should be destroyed using the function
1372 <function>ZOOM_connection_destroy</function>.
1375 void ZOOM_connection_option_set(ZOOM_connection c,
1376 const char *key, const char *val);
1378 void ZOOM_connection_option_setl(ZOOM_connection c,
1380 const char *val, int len);
1382 const char *ZOOM_connection_option_get(ZOOM_connection c,
1384 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1389 The functions <function>ZOOM_connection_option_set</function> and
1390 <function>ZOOM_connection_option_setl</function> allows you to
1391 set an option given by <parameter>key</parameter> to the value
1392 <parameter>value</parameter> for the connection.
1393 For <function>ZOOM_connection_option_set</function>, the
1394 value is assumed to be a 0-terminated string. Function
1395 <function>ZOOM_connection_option_setl</function> specifies a
1396 value of a certain size (len).
1399 Functions <function>ZOOM_connection_option_get</function> and
1400 <function>ZOOM_connection_option_getl</function> returns
1401 the value for an option given by <parameter>key</parameter>.
1403 <table id="zoom-connection-options" frame="top">
1404 <title>ZOOM Connection Options</title>
1406 <colspec colwidth="4*" colname="name"></colspec>
1407 <colspec colwidth="7*" colname="description"></colspec>
1408 <colspec colwidth="3*" colname="default"></colspec>
1411 <entry>Option</entry>
1412 <entry>Description</entry>
1413 <entry>Default</entry>
1418 implementationName</entry><entry>Name of Your client
1419 </entry><entry>none</entry></row>
1421 user</entry><entry>Authentication user name
1422 </entry><entry>none</entry></row>
1424 group</entry><entry>Authentication group name
1425 </entry><entry>none</entry></row>
1427 password</entry><entry>Authentication password.
1428 </entry><entry>none</entry></row>
1430 authenticationMode</entry><entry>How authentication is encoded.
1431 </entry><entry>basic</entry></row>
1433 host</entry><entry>Target host. This setting is "read-only".
1434 It's automatically set internally when connecting to a target.
1435 </entry><entry>none</entry></row>
1437 proxy</entry><entry>Proxy host. If set, the logical host
1438 is encoded in the otherInfo area of the Z39.50 Init PDU
1439 with OID 1.2.840.10003.10.1000.81.1.
1440 </entry><entry>none</entry></row>
1442 clientIP</entry><entry>Client IP. If set, is
1443 encoded in the otherInfo area of a Z39.50 PDU with OID
1444 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1445 of a client. Is used of ZOOM is used in a gateway of some sort.
1446 </entry><entry>none</entry></row>
1448 async</entry><entry>If true (1) the connection operates in
1449 asynchronous operation which means that all calls are non-blocking
1451 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1452 </entry><entry>0</entry></row>
1454 maximumRecordSize</entry><entry> Maximum size of single record.
1455 </entry><entry>1 MB</entry></row>
1457 preferredMessageSize</entry><entry> Maximum size of multiple records.
1458 </entry><entry>1 MB</entry></row>
1460 lang</entry><entry> Language for negotiation.
1461 </entry><entry>none</entry></row>
1463 charset</entry><entry> Character set for negotiation.
1464 </entry><entry>none</entry></row>
1466 serverImplementationId</entry><entry>
1467 Implementation ID of server. (The old targetImplementationId
1468 option is also supported for the benefit of old applications.)
1469 </entry><entry>none</entry></row>
1471 targetImplementationName</entry><entry>
1472 Implementation Name of server. (The old
1473 targetImplementationName option is also supported for the
1474 benefit of old applications.)
1475 </entry><entry>none</entry></row>
1477 serverImplementationVersion</entry><entry>
1478 Implementation Version of server. (the old
1479 targetImplementationVersion option is also supported for the
1480 benefit of old applications.)
1481 </entry><entry>none</entry></row>
1483 databaseName</entry><entry>One or more database names
1484 separated by character plus (<literal>+</literal>), which to
1485 be used by subsequent search requests on this Connection.
1486 </entry><entry>Default</entry></row>
1488 piggyback</entry><entry>True (1) if piggyback should be
1489 used in searches; false (0) if not.
1490 </entry><entry>1</entry></row>
1492 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1493 value, then target will return all records using small element set name
1494 </entry><entry>0</entry></row>
1496 largeSetLowerBound</entry><entry>If hits is greater than this
1497 value, the target will return no records.
1498 </entry><entry>1</entry></row>
1500 mediumSetPresentNumber</entry><entry>This value represents
1501 the number of records to be returned as part of a search when when
1502 hits is less than or equal to large set lower bound and if hits
1503 is greater than small set upper bound.
1504 </entry><entry>0</entry></row>
1506 smallSetElementSetName</entry><entry>
1507 The element set name to be used for small result sets.
1508 </entry><entry>none</entry></row>
1510 mediumSetElementSetName</entry><entry>
1511 The element set name to be for medium-sized result sets.
1512 </entry><entry>none</entry></row>
1514 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1515 After a successful Init, these options may be interrogated to
1516 discover whether the server claims to support the specified
1518 </entry><entry>none</entry></row>
1520 <entry>sru</entry><entry>
1521 SRU/Solr transport type. Must be either <literal>soap</literal>,
1522 <literal>get</literal>, <literal>post</literal>, or
1523 <literal>solr</literal>.
1524 </entry><entry>soap</entry></row>
1526 sru_version</entry><entry>
1527 SRU/SRW version. Should be <literal>1.1</literal>, or
1528 <literal>1.2</literal>. This is , prior to connect, the version
1529 to offer (highest version). And following connect (in fact
1530 first operation), holds the negotiated version with the server
1531 (same or lower version).
1532 </entry><entry>1.2</entry></row>
1533 <row id="zoom.extraArgs.option"><entry>
1534 extraArgs</entry><entry>
1535 Extra arguments for SRU/Solr URLs. The value must be
1536 URL encoded already.
1537 </entry><entry></entry></row>
1538 <row id="zoom.facets.option"><entry>
1539 facets</entry><entry>
1540 Requested or recommend facets may be given before a search is sent.
1541 The value of this setting is described in <xref linkend="facets"/>
1542 For inspection of the facets returned, refer to the functions
1543 described in <xref linkend="zoom.facets"/>.
1544 </entry><entry>none</entry></row>
1546 apdulog</entry><entry>
1547 If set to a true value such as "1", a log of low-level
1548 protocol packets is emitted on standard error stream. This
1549 can be very useful for debugging.
1550 </entry><entry>0</entry></row>
1552 saveAPDU</entry><entry>
1553 If set to a true value such as "1", a log of low-level
1554 protocol packets is saved. The log can be retrieved by reading
1555 option APDU. Setting saveAPDU always has the side effect of
1556 resetting the currently saved log. This setting is
1557 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1558 It is only recognized in
1559 <function>ZOOM_connection_option_set</function>.
1560 </entry><entry>0</entry></row>
1563 Returns the log of protocol packets. Will be empty if logging
1564 is not enabled (see saveAPDU above). This setting is
1565 <emphasis>read-only</emphasis>. It is only recognized if used
1566 in call to <function>ZOOM_connection_option_get</function> or
1567 <function>ZOOM_connection_option_getl</function>.
1568 </entry><entry></entry></row>
1570 memcached</entry><entry>
1571 If given and non-empty,
1572 <ulink url="&url.libmemcached;">libMemcached</ulink>
1573 will be configured for the connection.
1574 This option is inspected by ZOOM when a connection is established.
1575 If the <literal>memcached</literal> option is given
1576 and YAZ is compiled without libMemcached support, an internal
1577 diagnostic (10018) will be thrown.
1578 libMemcached support is available for YAZ 5.0.13 or later. If this
1579 option is supplied for an earlier version of YAZ, it is
1580 <emphasis>ignored</emphasis>.
1581 The value of this option is a list options - each is of the
1582 form <literal>--name=value</literal>.
1583 Option <literal>--server=</literal>host[:port] specifies a memcached
1584 server. It may be repeated for multiple memcached servers.
1585 Option <literal>--expire=</literal>seconds sets expiry time in seconds
1586 for how long result sets are to be cached.
1587 </entry><entry>none</entry></row>
1589 redis</entry><entry>
1590 If given and non-empty,
1591 a <ulink url="&url.redis;">redis</ulink> context will be created
1593 This option is inspected by ZOOM when a connection is established.
1594 If the <literal>redis</literal> option is given
1595 and YAZ is compiled without redis support, an internal
1596 diagnostic (10018) will be thrown.
1597 redis support is available for YAZ 5.2.0 or later. If this
1598 option is supplied for an earlier version of YAZ, it is
1599 <emphasis>ignored</emphasis>.
1600 The value of this option is a set options, similar to that
1601 of the memcached setting. At this stage only --server=host[:port]
1602 and --expire=seconds is supported.
1603 </entry><entry>none</entry></row>
1608 If either option <literal>lang</literal> or <literal>charset</literal>
1610 <ulink url="&url.z39.50.charneg;">
1611 Character Set and Language Negotiation</ulink> is in effect.
1614 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1615 const char **addinfo);
1616 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1617 const char **addinfo, const char **dset);
1620 Function <function>ZOOM_connection_error</function> checks for
1621 errors for the last operation(s) performed. The function returns
1622 zero if no errors occurred; non-zero otherwise indicating the error.
1623 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1624 holds messages for the error and additional-info if passed as
1625 non-<literal>NULL</literal>. Function
1626 <function>ZOOM_connection_error_x</function> is an extended version
1627 of <function>ZOOM_connection_error</function> that is capable of
1628 returning name of diagnostic set in <parameter>dset</parameter>.
1630 <sect2 id="zoom-connection-z39.50">
1631 <title>Z39.50 Protocol behavior</title>
1633 The calls <function>ZOOM_connection_new</function> and
1634 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1635 connection and sends an Initialize Request to the target if
1636 possible. In addition, the calls waits for an Initialize Response
1637 from the target and the result is inspected (OK or rejected).
1640 If <literal>proxy</literal> is set then the client will establish
1641 a TCP/IP connection with the peer as specified by the
1642 <literal>proxy</literal> host and the hostname as part of the
1643 connect calls will be set as part of the Initialize Request.
1644 The proxy server will then "forward" the PDU's transparently
1645 to the target behind the proxy.
1648 For the authentication parameters, if option <literal>user</literal>
1649 is set and both options <literal>group</literal> and
1650 <literal>pass</literal> are unset, then Open style
1651 authentication is used (Version 2/3) in which case the username
1652 is usually followed by a slash, then by a password.
1653 If either <literal>group</literal>
1654 or <literal>pass</literal> is set then idPass authentication
1655 (Version 3 only) is used. If none of the options are set, no
1656 authentication parameters are set as part of the Initialize Request
1660 When option <literal>async</literal> is 1, it really means that
1661 all network operations are postponed (and queued) until the
1662 function <literal>ZOOM_event</literal> is invoked. When doing so
1663 it doesn't make sense to check for errors after
1664 <literal>ZOOM_connection_new</literal> is called since that
1665 operation "connecting - and init" is still incomplete and the
1666 API cannot tell the outcome (yet).
1669 <sect2 id="zoom.sru.init.behavior">
1670 <title>SRU/Solr Protocol behavior</title>
1672 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1673 Inititialize Request, so the connection phase merely establishes a
1674 TCP/IP connection with the HTTP server.
1676 <para>Most of the ZOOM connection options do not
1677 affect SRU/Solr and they are ignored. However, future versions
1678 of &yaz; might honor <literal>implementationName</literal> and
1679 put that as part of User-Agent header for HTTP requests.
1682 The <literal>charset</literal> is used in the Content-Type header
1686 Setting <literal>authentcationMode</literal> specifies how
1687 authentication parameters are encoded for HTTP. The default is
1688 "<literal>basic</literal>" where <literal>user</literal> and
1689 <literal>password</literal> are encoded by using HTTP basic
1693 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1694 user and password are encoded in the URL by parameters
1695 <literal>x-username</literal> and <literal>x-password</literal> as
1696 given by the SRU standard.
1700 <sect1 id="zoom.query">
1701 <title>Queries</title>
1703 Query objects represents queries.
1706 ZOOM_query ZOOM_query_create(void);
1708 void ZOOM_query_destroy(ZOOM_query q);
1710 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1712 int ZOOM_query_cql(ZOOM_query s, const char *str);
1714 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1716 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1717 const char *criteria);
1720 Create query objects using <function>ZOOM_query_create</function>
1721 and destroy them by calling <function>ZOOM_query_destroy</function>.
1722 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1723 notation by using the
1724 function <function>ZOOM_query_prefix</function>.
1725 The <function>ZOOM_query_cql</function> specifies a CQL
1726 query to be sent to the server/target.
1727 More query types will be added in future versions of &yaz;, such as
1728 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1729 etc. In addition to a search, a sort criteria may be set. Function
1730 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1731 it takes sort criteria using the same string notation as
1732 yaz-client's <link linkend="sortspec">sort command</link>.
1734 <para id="zoom.query.sortby2">
1735 <function>ZOOM_query_sortby2</function> is similar to
1736 <function>ZOOM_query_sortby</function> but allows a strategy for
1737 sorting. The reason for the strategy parameter is that some
1738 protocols offers multiple ways of performing sorting.
1739 For example, Z39.50 has the standard sort, which is performed after
1740 search on an existing result set.
1741 It's also possible to use CQL in Z39.50 as the query type and use
1742 CQL's SORTBY keyword. Finally, Index Data's
1743 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1745 <table id="zoom-sort-strategy" frame="top">
1746 <title>ZOOM sort strategy</title>
1748 <colspec colwidth="2*" colname="name"/>
1749 <colspec colwidth="5*" colname="description"/>
1753 <entry>Description</entry>
1758 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1761 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1764 <entry>cql</entry><entry>CQL SORTBY</entry>
1767 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1770 <entry>solr</entry><entry>Solr sort</entry>
1773 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1774 solr for Solr protocol</entry>
1780 <sect1 id="zoom.resultsets"><title>Result sets</title>
1782 The result set object is a container for records returned from
1786 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1788 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1790 void ZOOM_resultset_destroy(ZOOM_resultset r);
1793 Function <function>ZOOM_connection_search</function> creates
1794 a result set given a connection and query.
1795 Destroy a result set by calling
1796 <function>ZOOM_resultset_destroy</function>.
1797 Simple clients may using PQF only may use function
1798 <function>ZOOM_connection_search_pqf</function> in which case
1799 creating query objects is not necessary.
1802 void ZOOM_resultset_option_set(ZOOM_resultset r,
1803 const char *key, const char *val);
1805 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1807 size_t ZOOM_resultset_size(ZOOM_resultset r);
1810 Functions <function>ZOOM_resultset_options_set</function> and
1811 <function>ZOOM_resultset_get</function> sets and gets an option
1812 for a result set similar to <function>ZOOM_connection_option_get</function>
1813 and <function>ZOOM_connection_option_set</function>.
1816 The number of hits also called result-count is returned by
1817 function <function>ZOOM_resultset_size</function>.
1819 <table id="zoom.resultset.options"
1820 frame="top"><title>ZOOM Result set Options</title>
1822 <colspec colwidth="4*" colname="name"></colspec>
1823 <colspec colwidth="7*" colname="description"></colspec>
1824 <colspec colwidth="2*" colname="default"></colspec>
1827 <entry>Option</entry>
1828 <entry>Description</entry>
1829 <entry>Default</entry>
1834 start</entry><entry>Offset of first record to be
1835 retrieved from target. First record has offset 0 unlike the
1836 protocol specifications where first record has position 1.
1837 This option affects ZOOM_resultset_search and
1838 ZOOM_resultset_search_pqf and must be set before any of
1839 these functions are invoked. If a range of
1840 records must be fetched manually after search,
1841 function ZOOM_resultset_records should be used.
1842 </entry><entry>0</entry></row>
1844 count</entry><entry>Number of records to be retrieved.
1845 This option affects ZOOM_resultset_search and
1846 ZOOM_resultset_search_pqf and must be set before any of
1847 these functions are invoked.
1848 </entry><entry>0</entry></row>
1850 presentChunk</entry><entry>The number of records to be
1851 requested from the server in each chunk (present request). The
1852 value 0 means to request all the records in a single chunk.
1853 (The old <literal>step</literal>
1854 option is also supported for the benefit of old applications.)
1855 </entry><entry>0</entry></row>
1857 elementSetName</entry><entry>Element-Set name of records.
1858 Most targets should honor element set name <literal>B</literal>
1859 and <literal>F</literal> for brief and full respectively.
1860 </entry><entry>none</entry></row>
1862 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1863 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1864 </entry><entry>none</entry></row>
1866 schema</entry><entry>Schema for retrieval, such as
1867 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1868 </entry><entry>none</entry></row>
1870 setname</entry><entry>Name of Result Set (Result Set ID).
1871 If this option isn't set, the ZOOM module will automatically
1872 allocate a result set name.
1873 </entry><entry>default</entry></row>
1875 rpnCharset</entry><entry>Character set for RPN terms.
1876 If this is set, ZOOM C will assume that the ZOOM application is
1877 running UTF-8. Terms in RPN queries are then converted to the
1878 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1879 of RPN terms and no conversion is performed.
1880 </entry><entry>none</entry></row>
1885 For servers that support Search Info report, the following
1886 options may be read using <function>ZOOM_resultset_get</function>.
1887 This detailed information is read after a successful search has
1891 This information is a list of of items, where each item is
1892 information about a term or subquery. All items in the list
1894 <literal>SearchResult.</literal><replaceable>no</replaceable>
1895 where no presents the item number (0=first, 1=second).
1896 Read <literal>searchresult.size</literal> to determine the
1899 <table id="zoom.search.info.report.options"
1900 frame="top"><title>Search Info Report Options</title>
1902 <colspec colwidth="4*" colname="name"></colspec>
1903 <colspec colwidth="7*" colname="description"></colspec>
1906 <entry>Option</entry>
1907 <entry>Description</entry>
1912 <entry>searchresult.size</entry>
1914 number of search result entries. This option is-nonexistant
1915 if no entries are returned by the server.
1919 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1920 <entry>sub query ID</entry>
1923 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1924 <entry>result count for item (number of hits)</entry>
1927 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1928 <entry>subquery term</entry>
1932 searchresult.<replaceable>no</replaceable>.interpretation.term
1934 <entry>interpretation term</entry>
1938 searchresult.<replaceable>no</replaceable>.recommendation.term
1940 <entry>recommendation term</entry>
1945 <sect2 id="zoom.z3950.resultset.sort">
1946 <title>Z39.50 Result-set Sort</title>
1948 void ZOOM_resultset_sort(ZOOM_resultset r,
1949 const char *sort_type, const char *sort_spec);
1951 int ZOOM_resultset_sort1(ZOOM_resultset r,
1952 const char *sort_type, const char *sort_spec);
1955 <function>ZOOM_resultset_sort</function> and
1956 <function>ZOOM_resultset_sort1</function> both sort an existing
1957 result-set. The sort_type parameter is not use. Set it to "yaz".
1958 The sort_spec is same notation as ZOOM_query_sortby and identical
1959 to that offered by yaz-client's
1960 <link linkend="sortspec">sort command</link>.
1963 These functions only work for Z39.50. Use the more generic utility
1964 <link linkend="zoom.query.sortby2">
1965 <function>ZOOM_query_sortby2</function></link>
1966 for other protocols (and even Z39.50).
1969 <sect2 id="zoom.z3950.resultset.behavior">
1970 <title>Z39.50 Protocol behavior</title>
1972 The creation of a result set involves at least a SearchRequest
1973 - SearchResponse protocol handshake. Following that, if a sort
1974 criteria was specified as part of the query, a SortRequest -
1975 SortResponse handshake takes place. Note that it is necessary to
1976 perform sorting before any retrieval takes place, so no records will
1977 be returned from the target as part of the SearchResponse because these
1978 would be unsorted. Hence, piggyback is disabled when sort criteria
1979 are set. Following Search - and a possible sort - Retrieval takes
1980 place - as one or more Present Requests/Response pairs being
1984 The API allows for two different modes for retrieval. A high level
1985 mode which is somewhat more powerful and a low level one.
1986 The low level is enabled when searching on a Connection object
1987 for which the settings
1988 <literal>smallSetUpperBound</literal>,
1989 <literal>mediumSetPresentNumber</literal> and
1990 <literal>largeSetLowerBound</literal> are set. The low level mode
1991 thus allows you to precisely set how records are returned as part
1992 of a search response as offered by the Z39.50 protocol.
1993 Since the client may be retrieving records as part of the
1994 search response, this mode doesn't work well if sorting is used.
1997 The high-level mode allows you to fetch a range of records from
1998 the result set with a given start offset. When you use this mode
1999 the client will automatically use piggyback if that is possible
2000 with the target and perform one or more present requests as needed.
2001 Even if the target returns fewer records as part of a present response
2002 because of a record size limit, etc. the client will repeat sending
2003 present requests. As an example, if option <literal>start</literal>
2004 is 0 (default) and <literal>count</literal> is 4, and
2005 <literal>piggyback</literal> is 1 (default) and no sorting criteria
2006 is specified, then the client will attempt to retrieve the 4
2007 records as part the search response (using piggyback). On the other
2008 hand, if either <literal>start</literal> is positive or if
2009 a sorting criteria is set, or if <literal>piggyback</literal>
2010 is 0, then the client will not perform piggyback but send Present
2014 If either of the options <literal>mediumSetElementSetName</literal> and
2015 <literal>smallSetElementSetName</literal> are unset, the value
2016 of option <literal>elementSetName</literal> is used for piggyback
2017 searches. This means that for the high-level mode you only have
2018 to specify one elementSetName option rather than three.
2021 <sect2 id="zoom.sru.resultset.behavior">
2022 <title>SRU Protocol behavior</title>
2024 Current version of &yaz; does not take advantage of a result set id
2025 returned by the SRU server. Future versions might do, however.
2026 Since, the ZOOM driver does not save result set IDs any
2027 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2028 with same query but, possibly, different offsets.
2031 Option <literal>schema</literal> specifies SRU schema
2032 for retrieval. However, options <literal>elementSetName</literal> and
2033 <literal>preferredRecordSyntax</literal> are ignored.
2036 Options <literal>start</literal> and <literal>count</literal>
2037 are supported by SRU.
2038 The remaining options
2039 <literal>piggyback</literal>,
2040 <literal>smallSetUpperBound</literal>,
2041 <literal>largeSetLowerBound</literal>,
2042 <literal>mediumSetPresentNumber</literal>,
2043 <literal>mediumSetElementSetName</literal>,
2044 <literal>smallSetElementSetName</literal> are
2048 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2049 If PQF is used, however, the PQF query is transferred anyway
2050 using non-standard element <literal>pQuery</literal> in
2051 SRU SearchRetrieveRequest.
2054 Solr queries has to be done in Solr query format.
2057 Unfortunately, SRU or Solr does not define a database setting. Hence,
2058 <literal>databaseName</literal> is unsupported and ignored.
2059 However, the path part in host parameter for functions
2060 <function>ZOOM_connecton_new</function> and
2061 <function>ZOOM_connection_connect</function> acts as a
2062 database (at least for the &yaz; SRU server).
2066 <sect1 id="zoom.records">
2067 <title>Records</title>
2069 A record object is a retrieval record on the client side -
2070 created from result sets.
2073 void ZOOM_resultset_records(ZOOM_resultset r,
2075 size_t start, size_t count);
2076 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2078 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2081 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2082 const char **addinfo, const char **diagset);
2084 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2086 void ZOOM_record_destroy(ZOOM_record rec);
2089 References to temporary records are returned by functions
2090 <function>ZOOM_resultset_records</function> or
2091 <function>ZOOM_resultset_record</function>.
2094 If a persistent reference to a record is desired
2095 <function>ZOOM_record_clone</function> should be used.
2096 It returns a record reference that should be destroyed
2097 by a call to <function>ZOOM_record_destroy</function>.
2100 A single record is returned by function
2101 <function>ZOOM_resultset_record</function> that takes a
2102 position as argument. First record has position zero.
2103 If no record could be obtained <literal>NULL</literal> is returned.
2106 Error information for a record can be checked with
2107 <function>ZOOM_record_error</function> which returns non-zero
2108 (error code) if record is in error, called <emphasis>Surrogate
2109 Diagnostics</emphasis> in Z39.50.
2112 Function <function>ZOOM_resultset_records</function> retrieves
2113 a number of records from a result set. Parameter <literal>start</literal>
2114 and <literal>count</literal> specifies the range of records to
2115 be returned. Upon completion array
2116 <literal>recs[0], ..recs[count-1]</literal>
2117 holds record objects for the records. The array of records
2118 <literal>recs</literal> should be allocated prior the call
2119 <function>ZOOM_resultset_records</function>. Note that for those
2120 records that couldn't be retrieved from the target
2121 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2123 <para id="zoom.record.get">
2124 In order to extract information about a single record,
2125 <function>ZOOM_record_get</function> is provided. The
2126 function returns a pointer to certain record information. The
2127 nature (type) of the pointer depends on the parameter,
2128 <parameter>type</parameter>.
2131 The <parameter>type</parameter> is a string of the format:
2134 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>][;base64=<replaceable>xpath</replaceable>]
2137 If <literal>charset</literal> is given, then <replaceable>from</replaceable>
2138 specifies the character set of the record in its original form
2139 (as returned by the server), <replaceable>to</replaceable> specifies
2140 the output (returned) character set encoding.
2141 If <replaceable>to</replaceable> is omitted, then UTF-8 is assumed.
2142 If charset is not given, then no character set conversion takes place.
2143 OPAC records may be returned in a different
2144 set from the bibliographic MARC record. If this is this the case,
2145 <replaceable>opacfrom</replaceable> should be set to the character set
2146 of the OPAC record part.
2150 The <literal>format</literal> is generic but can only be used to
2151 specify XML indentation when the value <replaceable>v</replaceable>
2152 is 1 (<literal>format=1</literal>).
2155 The <literal>base64</literal> allows a full record to be extracted
2156 from base64-encoded string in an XML document.
2160 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2163 Specifying the base64 parameter requires YAZ 4.2.35 or later.
2167 The format argument controls whether record data should be XML
2168 pretty-printed (post process operation).
2169 It is enabled only if format value <replaceable>v</replaceable> is
2170 <literal>1</literal> and the record content is XML well-formed.
2173 In addition, for certain types, the length
2174 <literal>len</literal> passed will be set to the size in bytes of
2175 the returned information.
2178 The following are the supported values for <replaceable>form</replaceable>.
2180 <varlistentry><term><literal>database</literal></term>
2181 <listitem><para>Database of record is returned
2182 as a C null-terminated string. Return type
2183 <literal>const char *</literal>.
2186 <varlistentry><term><literal>syntax</literal></term>
2187 <listitem><para>The transfer syntax of the record is returned
2188 as a C null-terminated string containing the symbolic name of
2189 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2191 <literal>const char *</literal>.
2194 <varlistentry><term><literal>schema</literal></term>
2195 <listitem><para>The schema of the record is returned
2196 as a C null-terminated string. Return type is
2197 <literal>const char *</literal>.
2200 <varlistentry><term><literal>render</literal></term>
2201 <listitem><para>The record is returned in a display friendly
2202 format. Upon completion buffer is returned
2203 (type <literal>const char *</literal>) and length is stored in
2204 <literal>*len</literal>.
2207 <varlistentry><term><literal>raw</literal></term>
2208 <listitem><para>The record is returned in the internal
2209 YAZ specific format. For GRS-1, Explain, and others, the
2210 raw data is returned as type
2211 <literal>Z_External *</literal> which is just the type for
2212 the member <literal>retrievalRecord</literal> in
2213 type <literal>NamePlusRecord</literal>.
2214 For SUTRS and octet aligned record (including all MARCs) the
2215 octet buffer is returned and the length of the buffer.
2218 <varlistentry><term><literal>xml</literal></term>
2219 <listitem><para>The record is returned in XML if possible.
2220 SRU, Solr and Z39.50 records with transfer syntax XML are
2221 returned verbatim. MARC records are returned in
2222 <ulink url="&url.marcxml;">
2225 (converted from ISO2709 to MARCXML by YAZ).
2226 OPAC records are also converted to XML and the
2227 bibliographic record is converted to MARCXML (when possible).
2228 GRS-1 records are not supported for this form.
2229 Upon completion, the XML buffer is returned
2230 (type <literal>const char *</literal>) and length is stored in
2231 <literal>*len</literal>.
2234 <varlistentry><term><literal>opac</literal></term>
2235 <listitem><para>OPAC information for record is returned in XML
2236 if an OPAC record is present at the position given. If no
2237 OPAC record is present, a NULL pointer is returned.
2240 <varlistentry><term><literal>txml</literal></term>
2241 <listitem><para>The record is returned in TurboMARC if possible.
2242 SRU and Z39.50 records with transfer syntax XML are
2243 returned verbatim. MARC records are returned in
2244 <link linkend="tools.turbomarc">
2247 (converted from ISO2709 to TurboMARC by YAZ).
2248 Upon completion, the XML buffer is returned
2249 (type <literal>const char *</literal>) and length is stored in
2250 <literal>*len</literal>.
2253 <varlistentry><term><literal>json</literal></term>
2254 <listitem><para>Like xml, but MARC records are converted to
2255 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2263 <ulink url="&url.marc21;">MARC21</ulink>
2265 <ulink url="&url.marc8;">MARC-8</ulink>
2266 character set encoding.
2267 An application that wishes to display in Latin-1 would use
2269 render; charset=marc8,iso-8859-1
2272 <sect2 id="zoom.z3950.record.behavior">
2273 <title>Z39.50 Protocol behavior</title>
2275 The functions <function>ZOOM_resultset_record</function> and
2276 <function>ZOOM_resultset_records</function> inspects the client-side
2277 record cache. Records not found in cache are fetched using
2279 The functions may block (and perform network I/O) - even though option
2280 <literal>async</literal> is 1, because they return records objects.
2281 (and there's no way to return records objects without retrieving them!).
2284 There is a trick, however, in the usage of function
2285 <function>ZOOM_resultset_records</function> that allows for
2286 delayed retrieval (and makes it non-blocking). By using
2287 a null pointer for <parameter>recs</parameter> you're indicating
2288 you're not interested in getting records objects
2289 <emphasis>now</emphasis>.
2292 <sect2 id="zoom.sru.record.behavior">
2293 <title>SRU/Solr Protocol behavior</title>
2295 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2296 as if they where Z39.50 records with transfer syntax XML and
2297 no element set name or database name.
2301 <sect1 id="zoom.facets"><title>Facets</title>
2303 Facet operations is not part of the official ZOOM specification, but
2304 is an Index Data extension for YAZ-based Z39.50 targets,
2305 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2307 Facets may be requestd by the
2308 <link linkend="zoom.facets.option">facets</link> option before a
2310 For inspection of the returned facets, the following functions are
2314 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2316 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2317 const char *facet_name);
2319 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2322 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2324 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2326 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2328 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2329 size_t idx, int *freq);
2332 References to temporary structures are returned by all functions.
2333 They are only valid as long the Result set is valid.
2334 <function>ZOOM_resultset_get_facet_field</function> or
2335 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2336 <function>ZOOM_resultset_facets</function>.
2337 <function>ZOOM_facet_field_name</function>.
2338 <function>ZOOM_facet_field_get_term</function>.
2340 <para id="zoom.resultset.get_facet_field">
2341 A single Facet field is returned by function
2342 <function>ZOOM_resultset_get_facet_field</function> or
2343 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2344 a result set and facet name or positive index respectively. First
2345 facet has position zero. If no facet could be obtained (invalid name
2346 or index out of bounds) <literal>NULL</literal> is returned.
2348 <para id="zoom.resultset.facets">
2349 An array of facets field can be returned by
2350 <function>ZOOM_resultset_facets</function>. The length of the array is
2351 given by <function>ZOOM_resultset_facets_size</function>. The array is
2352 zero-based and last entry will be at
2353 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2355 <para id="zoom.resultset.facets_names">
2356 It is possible to interate over facets by name, by calling
2357 <function>ZOOM_resultset_facets_names</function>.
2358 This will return an const array of char * where each string can be used
2359 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2362 Function <function>ZOOM_facet_field_name</function> gets the request
2363 facet name from a returned facet field.
2366 Function <function>ZOOM_facet_field_get_term</function> returns the
2367 idx'th term and term count for a facet field.
2368 Idx must between 0 and
2369 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2370 returned reference will be <literal>NULL</literal>. On a valid idx, the
2371 value of the freq reference will be the term count.
2372 The <literal>freq</literal> parameter must be valid pointer to integer.
2375 <sect1 id="zoom.scan"><title>Scan</title>
2377 This section describes an interface for Scan. Scan is not an
2378 official part of the ZOOM model yet. The result of a scan operation
2379 is the <literal>ZOOM_scanset</literal> which is a set of terms
2380 returned by a target.
2384 The Scan interface is supported for both Z39.50, SRU and Solr.
2388 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2389 const char *startpqf);
2391 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2394 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2396 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2397 size_t *occ, size_t *len);
2399 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2400 size_t *occ, size_t *len);
2402 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2404 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2407 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2411 The scan set is created by function
2412 <function>ZOOM_connection_scan</function> which performs a scan
2413 operation on the connection using the specified
2414 <parameter>startpqf</parameter>.
2415 If the operation was successful, the size of the scan set can be
2416 retrieved by a call to <function>ZOOM_scanset_size</function>.
2417 Like result sets, the items are numbered 0,..size-1.
2418 To obtain information about a particular scan term, call function
2419 <function>ZOOM_scanset_term</function>. This function takes
2420 a scan set offset <literal>pos</literal> and returns a pointer
2421 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2423 If present, the <literal>occ</literal> and <literal>len</literal>
2424 are set to the number of occurrences and the length
2425 of the actual term respectively.
2426 <function>ZOOM_scanset_display_term</function> is similar to
2427 <function>ZOOM_scanset_term</function> except that it returns
2428 the <emphasis>display term</emphasis> rather than the raw term.
2429 In a few cases, the term is different from display term. Always
2430 use the display term for display and the raw term for subsequent
2431 scan operations (to get more terms, next scan result, etc).
2434 A scan set may be freed by a call to function
2435 <function>ZOOM_scanset_destroy</function>.
2436 Functions <function>ZOOM_scanset_option_get</function> and
2437 <function>ZOOM_scanset_option_set</function> retrieves and sets
2438 an option respectively.
2441 The <parameter>startpqf</parameter> is a subset of PQF, namely
2442 the Attributes+Term part. Multiple <literal>@attr</literal> can
2443 be used. For example to scan in title (complete) phrases:
2445 @attr 1=4 @attr 6=2 "science o"
2449 The <function>ZOOM_connecton_scan1</function> is a newer and
2450 more generic alternative to <function>ZOOM_connection_scan</function>
2451 which allows to use both CQL and PQF for Scan.
2453 <table frame="top" id="zoom.scanset.options">
2454 <title>ZOOM Scan Set Options</title>
2456 <colspec colwidth="4*" colname="name"></colspec>
2457 <colspec colwidth="7*" colname="description"></colspec>
2458 <colspec colwidth="2*" colname="default"></colspec>
2461 <entry>Option</entry>
2462 <entry>Description</entry>
2463 <entry>Default</entry>
2468 number</entry><entry>Number of Scan Terms requested in next scan.
2469 After scan it holds the actual number of terms returned.
2470 </entry><entry>20</entry></row>
2472 position</entry><entry>Preferred Position of term in response
2473 in next scan; actual position after completion of scan.
2474 </entry><entry>1</entry></row>
2476 stepSize</entry><entry>Step Size
2477 </entry><entry>0</entry></row>
2479 scanStatus</entry><entry>An integer indicating the Scan Status
2481 </entry><entry>0</entry></row>
2483 rpnCharset</entry><entry>Character set for RPN terms.
2484 If this is set, ZOOM C will assume that the ZOOM application is
2485 running UTF-8. Terms in RPN queries are then converted to the
2486 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2487 of RPN terms and no conversion is performed.
2488 </entry><entry>none</entry></row>
2493 <sect1 id="zoom.extendedservices">
2494 <title>Extended Services</title>
2496 ZOOM offers an interface to a subset of the Z39.50 extended services
2497 as well as a few privately defined ones:
2502 Z39.50 Item Order (ILL).
2503 See <xref linkend="zoom.item.order"/>.
2508 Record Update. This allows a client to insert, modify or delete
2510 See <xref linkend="zoom.record.update"/>.
2515 Database Create. This a non-standard feature. Allows a client
2516 to create a database.
2517 See <xref linkend="zoom.database.create"/>.
2522 Database Drop. This a non-standard feature. Allows a client
2523 to delete/drop a database.
2524 See <xref linkend="zoom.database.drop"/>.
2529 Commit operation. This a non-standard feature. Allows a client
2530 to commit operations.
2531 See <xref linkend="zoom.commit"/>.
2534 <!-- all the ILL PDU options should go here too -->
2537 To create an extended service operation a <literal>ZOOM_package</literal>
2538 must be created. The operation is a five step operation. The
2539 package is created, package is configured by means of options,
2540 the package is send, result is inspected (by means of options),
2541 the package is destroyed.
2544 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2545 ZOOM_options options);
2547 const char *ZOOM_package_option_get(ZOOM_package p,
2549 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2551 void ZOOM_package_send(ZOOM_package p, const char *type);
2553 void ZOOM_package_destroy(ZOOM_package p);
2556 The <function>ZOOM_connection_package</function> creates a
2557 package for the connection given using the options specified.
2560 Functions <function>ZOOM_package_option_get</function> and
2561 <function>ZOOM_package_option_set</function> gets and sets
2565 <function>ZOOM_package_send</function> sends
2566 the package the via connection specified in
2567 <function>ZOOM_connection_package</function>.
2568 The <parameter>type</parameter> specifies the actual extended service
2569 package type to be sent.
2571 <table frame="top" id="zoom.extendedservices.options">
2572 <title>Extended Service Common Options</title>
2574 <colspec colwidth="4*" colname="name"></colspec>
2575 <colspec colwidth="7*" colname="description"></colspec>
2576 <colspec colwidth="3*" colname="default"></colspec>
2579 <entry>Option</entry>
2580 <entry>Description</entry>
2581 <entry>Default</entry>
2586 <entry>package-name</entry>
2587 <entry>Extended Service Request package name. Must be specified
2588 as part of a request</entry>
2592 <entry>user-id</entry>
2593 <entry>User ID of Extended Service Package. Is a request option</entry>
2597 <entry>function</entry>
2599 Function of package - one of <literal>create</literal>,
2600 <literal>delete</literal>, <literal>modify</literal>. Is
2603 <entry><literal>create</literal></entry>
2606 <entry>waitAction</entry>
2608 Wait action for package. Possible values:
2609 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2610 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2612 <entry><literal>waitIfPossible</literal></entry>
2615 <entry>targetReference</entry>
2617 Target Reference. This is part of the response as returned
2618 by the server. Read it after a successful operation.
2620 <entry><literal>none</literal></entry>
2625 <sect2 id="zoom.item.order">
2626 <title>Item Order</title>
2628 For Item Order, type must be set to <literal>itemorder</literal> in
2629 <function>ZOOM_package_send</function>.
2632 <table frame="top" id="zoom.item.order.options">
2633 <title>Item Order Options</title>
2635 <colspec colwidth="4*" colname="name"></colspec>
2636 <colspec colwidth="7*" colname="description"></colspec>
2637 <colspec colwidth="3*" colname="default"></colspec>
2640 <entry>Option</entry>
2641 <entry>Description</entry>
2642 <entry>Default</entry>
2647 <entry>contact-name</entry>
2648 <entry>ILL contact name</entry>
2652 <entry>contact-phone</entry>
2653 <entry>ILL contact phone</entry>
2657 <entry>contact-email</entry>
2658 <entry>ILL contact email</entry>
2662 <entry>itemorder-setname</entry>
2663 <entry>Name of result set for record</entry>
2664 <entry>default</entry>
2667 <entry>itemorder-item</entry>
2668 <entry>Position for item (record) requested. An integer</entry>
2675 There are two variants of item order: ILL-variant and
2676 XML document variant. In order to use the XML variant the setting
2677 <literal>doc</literal> must hold the XML item order document. If that
2678 setting is unset, the ILL-variant is used.
2681 <table frame="top" id="zoom.illrequest.options">
2682 <title>ILL Request Options</title>
2684 <colspec colwidth="4*" colname="name"></colspec>
2687 <entry>Option</entry>
2691 <row><entry>protocol-version-num</entry></row>
2692 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,person</entry></row>
2693 <row><entry>transaction-id,initial-requester-id,person-or-institution-symbol,institution</entry></row>
2694 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-person</entry></row>
2695 <row><entry>transaction-id,initial-requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2696 <row><entry>transaction-id,transaction-group-qualifier</entry></row>
2697 <row><entry>transaction-id,transaction-qualifier</entry></row>
2698 <row><entry>transaction-id,sub-transaction-qualifier</entry></row>
2699 <row><entry>service-date-time,this,date</entry></row>
2700 <row><entry>service-date-time,this,time</entry></row>
2701 <row><entry>service-date-time,original,date</entry></row>
2702 <row><entry>service-date-time,original,time</entry></row>
2703 <row><entry>requester-id,person-or-institution-symbol,person</entry></row>
2704 <row><entry>requester-id,person-or-institution-symbol,institution</entry></row>
2705 <row><entry>requester-id,name-of-person-or-institution,name-of-person</entry></row>
2706 <row><entry>requester-id,name-of-person-or-institution,name-of-institution</entry></row>
2707 <row><entry>responder-id,person-or-institution-symbol,person</entry></row>
2708 <row><entry>responder-id,person-or-institution-symbol,institution</entry></row>
2709 <row><entry>responder-id,name-of-person-or-institution,name-of-person</entry></row>
2710 <row><entry>responder-id,name-of-person-or-institution,name-of-institution</entry></row>
2711 <row><entry>transaction-type</entry></row>
2712 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2713 <row><entry>delivery-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2714 <row><entry>delivery-address,postal-address,extended-postal-delivery-address</entry></row>
2715 <row><entry>delivery-address,postal-address,street-and-number</entry></row>
2716 <row><entry>delivery-address,postal-address,post-office-box</entry></row>
2717 <row><entry>delivery-address,postal-address,city</entry></row>
2718 <row><entry>delivery-address,postal-address,region</entry></row>
2719 <row><entry>delivery-address,postal-address,country</entry></row>
2720 <row><entry>delivery-address,postal-address,postal-code</entry></row>
2721 <row><entry>delivery-address,electronic-address,telecom-service-identifier</entry></row>
2722 <row><entry>delivery-address,electronic-address,telecom-service-addreess</entry></row>
2723 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-person</entry></row>
2724 <row><entry>billing-address,postal-address,name-of-person-or-institution,name-of-institution</entry></row>
2725 <row><entry>billing-address,postal-address,extended-postal-delivery-address</entry></row>
2726 <row><entry>billing-address,postal-address,street-and-number</entry></row>
2727 <row><entry>billing-address,postal-address,post-office-box</entry></row>
2728 <row><entry>billing-address,postal-address,city</entry></row>
2729 <row><entry>billing-address,postal-address,region</entry></row>
2730 <row><entry>billing-address,postal-address,country</entry></row>
2731 <row><entry>billing-address,postal-address,postal-code</entry></row>
2732 <row><entry>billing-address,electronic-address,telecom-service-identifier</entry></row>
2733 <row><entry>billing-address,electronic-address,telecom-service-addreess</entry></row>
2734 <row><entry>ill-service-type</entry></row>
2735 <row><entry>requester-optional-messages,can-send-RECEIVED</entry></row>
2736 <row><entry>requester-optional-messages,can-send-RETURNED</entry></row>
2737 <row><entry>requester-optional-messages,requester-SHIPPED</entry></row>
2738 <row><entry>requester-optional-messages,requester-CHECKED-IN</entry></row>
2739 <row><entry>search-type,level-of-service</entry></row>
2740 <row><entry>search-type,need-before-date</entry></row>
2741 <row><entry>search-type,expiry-date</entry></row>
2742 <row><entry>search-type,expiry-flag</entry></row>
2743 <row><entry>place-on-hold</entry></row>
2744 <row><entry>client-id,client-name</entry></row>
2745 <row><entry>client-id,client-status</entry></row>
2746 <row><entry>client-id,client-identifier</entry></row>
2747 <row><entry>item-id,item-type</entry></row>
2748 <row><entry>item-id,call-number</entry></row>
2749 <row><entry>item-id,author</entry></row>
2750 <row><entry>item-id,title</entry></row>
2751 <row><entry>item-id,sub-title</entry></row>
2752 <row><entry>item-id,sponsoring-body</entry></row>
2753 <row><entry>item-id,place-of-publication</entry></row>
2754 <row><entry>item-id,publisher</entry></row>
2755 <row><entry>item-id,series-title-number</entry></row>
2756 <row><entry>item-id,volume-issue</entry></row>
2757 <row><entry>item-id,edition</entry></row>
2758 <row><entry>item-id,publication-date</entry></row>
2759 <row><entry>item-id,publication-date-of-component</entry></row>
2760 <row><entry>item-id,author-of-article</entry></row>
2761 <row><entry>item-id,title-of-article</entry></row>
2762 <row><entry>item-id,pagination</entry></row>
2763 <row><entry>item-id,ISBN</entry></row>
2764 <row><entry>item-id,ISSN</entry></row>
2765 <row><entry>item-id,additional-no-letters</entry></row>
2766 <row><entry>item-id,verification-reference-source</entry></row>
2767 <row><entry>copyright-complicance</entry></row>
2768 <row><entry>retry-flag</entry></row>
2769 <row><entry>forward-flag</entry></row>
2770 <row><entry>requester-note</entry></row>
2771 <row><entry>forward-note</entry></row>
2776 <sect2 id="zoom.record.update">
2777 <title>Record Update</title>
2779 For Record Update, type must be set to <literal>update</literal> in
2780 <function>ZOOM_package_send</function>.
2782 <table frame="top" id="zoom.record.update.options">
2783 <title>Record Update Options</title>
2785 <colspec colwidth="4*" colname="name"></colspec>
2786 <colspec colwidth="7*" colname="description"></colspec>
2787 <colspec colwidth="3*" colname="default"></colspec>
2790 <entry>Option</entry>
2791 <entry>Description</entry>
2792 <entry>Default</entry>
2797 <entry>action</entry>
2799 The update action. One of
2800 <literal>specialUpdate</literal>,
2801 <literal>recordInsert</literal>,
2802 <literal>recordReplace</literal>,
2803 <literal>recordDelete</literal>,
2804 <literal>elementUpdate</literal>.
2806 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2809 <entry>recordIdOpaque</entry>
2810 <entry>Opaque Record ID</entry>
2814 <entry>recordIdNumber</entry>
2815 <entry>Record ID number</entry>
2819 <entry>record</entry>
2820 <entry>The record itself</entry>
2824 <entry>recordOpaque</entry>
2825 <entry>Specifies an opaque record which is
2826 encoded as an ASN.1 ANY type with the OID as tiven by option
2827 <literal>syntax</literal> (see below).
2828 Option <literal>recordOpaque</literal> is an alternative
2829 to record - and <literal>record</literal> option (above) is
2830 ignored if recordOpaque is set. This option is only available in
2831 YAZ 3.0.35 and later and is meant to facilitate Updates with
2837 <entry>syntax</entry>
2838 <entry>The record syntax (transfer syntax). Is a string that
2839 is a known record syntax.
2841 <entry>no syntax</entry>
2844 <entry>databaseName</entry>
2845 <entry>Database from connection object</entry>
2846 <entry>Default</entry>
2849 <entry>correlationInfo.note</entry>
2850 <entry>Correlation Info Note (string)</entry>
2854 <entry>correlationInfo.id</entry>
2855 <entry>Correlation Info ID (integer)</entry>
2859 <entry>elementSetName</entry>
2860 <entry>Element Set for Record</entry>
2864 <entry>updateVersion</entry>
2865 <entry>Record Update version which holds one of the values
2866 1, 2 or 3. Each version has a distinct OID:
2868 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2870 (second version) and
2871 1.2.840.10003.9.5.1.1
2872 (<ulink url="&url.z39.50.extupdate3;">third and
2873 newest version</ulink>).
2883 <sect2 id="zoom.database.create"><title>Database Create</title>
2885 For Database Create, type must be set to <literal>create</literal> in
2886 <function>ZOOM_package_send</function>.
2889 <table frame="top" id="zoom.database.create.options">
2890 <title>Database Create Options</title>
2892 <colspec colwidth="4*" colname="name"></colspec>
2893 <colspec colwidth="7*" colname="description"></colspec>
2894 <colspec colwidth="3*" colname="default"></colspec>
2897 <entry>Option</entry>
2898 <entry>Description</entry>
2899 <entry>Default</entry>
2904 <entry>databaseName</entry>
2905 <entry>Database from connection object</entry>
2906 <entry>Default</entry>
2912 <sect2 id="zoom.database.drop">
2913 <title>Database Drop</title>
2915 For Database Drop, type must be set to <literal>drop</literal> in
2916 <function>ZOOM_package_send</function>.
2918 <table frame="top" id="zoom.database.drop.options">
2919 <title>Database Drop Options</title>
2921 <colspec colwidth="4*" colname="name"></colspec>
2922 <colspec colwidth="7*" colname="description"></colspec>
2923 <colspec colwidth="3*" colname="default"></colspec>
2926 <entry>Option</entry>
2927 <entry>Description</entry>
2928 <entry>Default</entry>
2933 <entry>databaseName</entry>
2934 <entry>Database from connection object</entry>
2935 <entry>Default</entry>
2941 <sect2 id="zoom.commit">
2942 <title>Commit Operation</title>
2944 For Commit, type must be set to <literal>commit</literal> in
2945 <function>ZOOM_package_send</function>.
2948 <sect2 id="zoom.extended.services.behavior">
2949 <title>Protocol behavior</title>
2951 All the extended services are Z39.50-only.
2955 The database create, drop and commit services are privately defined
2957 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2963 <sect1 id="zoom.options">
2964 <title>Options</title>
2966 Most &zoom; objects provide a way to specify options to change behavior.
2967 From an implementation point of view a set of options is just like
2968 an associative array / hash.
2971 ZOOM_options ZOOM_options_create(void);
2973 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
2975 void ZOOM_options_destroy(ZOOM_options opt);
2978 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
2980 void ZOOM_options_set(ZOOM_options opt, const char *name,
2984 typedef const char *(*ZOOM_options_callback)
2985 (void *handle, const char *name);
2987 ZOOM_options_callback
2988 ZOOM_options_set_callback(ZOOM_options opt,
2989 ZOOM_options_callback c,
2993 <sect1 id="zoom.queryconversions">
2994 <title>Query conversions</title>
2996 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
2997 ZOOM_connection conn);
2999 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
3001 int *ccl_error, const char **error_string,
3005 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
3006 client-side, into RPN which may be passed to the server.
3007 This is useful for server's that don't themselves
3008 support CQL, for which <function>ZOOM_query_cql</function> is useless.
3009 `conn' is used only as a place to stash diagnostics if compilation
3010 fails; if this information is not needed, a null pointer may be used.
3011 The CQL conversion is driven by option <literal>cqlfile</literal> from
3012 connection conn. This specifies a conversion file (eg pqf.properties)
3013 which <emphasis>must</emphasis> be present.
3016 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
3017 client-side, into RPN which may be passed to the server.
3018 The conversion is driven by the specification given by
3019 <literal>config</literal>. Upon completion 0 is returned on success; -1
3020 is returned on on failure. Om failure <literal>error_string</literal> and
3021 <literal>error_pos</literal> holds error message and position of
3022 first error in original CCL string.
3025 <sect1 id="zoom.events"><title>Events</title>
3027 If you're developing non-blocking applications, you have to deal
3031 int ZOOM_event(int no, ZOOM_connection *cs);
3034 The <function>ZOOM_event</function> executes pending events for
3035 a number of connections. Supply the number of connections in
3036 <literal>no</literal> and an array of connections in
3037 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
3038 A pending event could be a sending a search, receiving a response,
3040 When an event has occurred for one of the connections, this function
3041 returns a positive integer <literal>n</literal> denoting that an event
3042 occurred for connection <literal>cs[n-1]</literal>.
3043 When no events are pending for the connections, a value of zero is
3045 To ensure that all outstanding requests are performed call this function
3046 repeatedly until zero is returned.
3049 If <function>ZOOM_event</function> returns and returns non-zero, the
3050 last event that occurred can be expected.
3053 int ZOOM_connection_last_event(ZOOM_connection cs);
3056 <function>ZOOM_connection_last_event</function> returns an event type
3057 (integer) for the last event.
3060 <table frame="top" id="zoom.event.ids">
3061 <title>ZOOM Event IDs</title>
3063 <colspec colwidth="4*" colname="name"></colspec>
3064 <colspec colwidth="7*" colname="description"></colspec>
3067 <entry>Event</entry>
3068 <entry>Description</entry>
3073 <entry>ZOOM_EVENT_NONE</entry>
3074 <entry>No event has occurred</entry>
3077 <entry>ZOOM_EVENT_CONNECT</entry>
3078 <entry>TCP/IP connect has initiated</entry>
3081 <entry>ZOOM_EVENT_SEND_DATA</entry>
3082 <entry>Data has been transmitted (sending)</entry>
3085 <entry>ZOOM_EVENT_RECV_DATA</entry>
3086 <entry>Data has been received)</entry>
3089 <entry>ZOOM_EVENT_TIMEOUT</entry>
3090 <entry>Timeout</entry>
3093 <entry>ZOOM_EVENT_UNKNOWN</entry>
3094 <entry>Unknown event</entry>
3097 <entry>ZOOM_EVENT_SEND_APDU</entry>
3098 <entry>An APDU has been transmitted (sending)</entry>
3101 <entry>ZOOM_EVENT_RECV_APDU</entry>
3102 <entry>An APDU has been received</entry>
3105 <entry>ZOOM_EVENT_RECV_RECORD</entry>
3106 <entry>A result-set record has been received</entry>
3109 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
3110 <entry>A search result been received</entry>
3117 <chapter id="server">
3118 <title>Generic server</title>
3119 <sect1 id="server.introduction"><title>Introduction</title>
3121 If you aren't into documentation, a good way to learn how the
3122 back end interface works is to look at the <filename>backend.h</filename>
3123 file. Then, look at the small dummy-server in
3124 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
3125 file also makes a good reference, once you've chewed your way through
3126 the prose of this file.
3129 If you have a database system that you would like to make available by
3130 means of Z39.50 or SRU, &yaz; basically offers your two options. You
3131 can use the APIs provided by the &asn;, &odr;, and &comstack;
3133 create and decode PDUs, and exchange them with a client.
3134 Using this low-level interface gives you access to all fields and
3135 options of the protocol, and you can construct your server as close
3136 to your existing database as you like.
3137 It is also a fairly involved process, requiring
3138 you to set up an event-handling mechanism, protocol state machine,
3139 etc. To simplify server implementation, we have implemented a compact
3140 and simple, but reasonably full-functioned server-frontend that will
3141 handle most of the protocol mechanics, while leaving you to
3142 concentrate on your database interface.
3146 The backend interface was designed in anticipation of a specific
3147 integration task, while still attempting to achieve some degree of
3148 generality. We realize fully that there are points where the
3149 interface can be improved significantly. If you have specific
3150 functions or parameters that you think could be useful, send us a
3151 mail (or better, sign on to the mailing list referred to in the
3152 top-level README file). We will try to fit good suggestions into future
3153 releases, to the extent that it can be done without requiring
3154 too many structural changes in existing applications.
3159 The &yaz; server does not support XCQL.
3163 <sect1 id="server.frontend">
3164 <title>The Database Frontend</title>
3166 We refer to this software as a generic database frontend. Your
3167 database system is the <emphasis>backend database</emphasis>, and the
3168 interface between the two is called the <emphasis>backend API</emphasis>.
3169 The backend API consists of a small number of function handlers and
3170 structure definitions. You are required to provide the
3171 <function>main()</function> routine for the server (which can be
3172 quite simple), as well as a set of handlers to match each of the
3174 The interface functions that you write can use any mechanism you like
3175 to communicate with your database system: You might link the whole
3176 thing together with your database application and access it by
3177 function calls; you might use IPC to talk to a database server
3178 somewhere; or you might link with third-party software that handles
3179 the communication for you (like a commercial database client library).
3180 At any rate, the handlers will perform the tasks of:
3193 Scanning the database index (optional - if you wish to implement SCAN).
3196 Extended Services (optional).
3199 Result-Set Delete (optional).
3202 Result-Set Sort (optional).
3205 Return Explain for SRU (optional).
3209 (more functions will be added in time to support as much of
3210 Z39.50-1995 as possible).
3213 <sect1 id="server.backend">
3214 <title>The Backend API</title>
3216 The header file that you need to use the interface are in the
3217 <filename>include/yaz</filename> directory. It's called
3218 <filename>backend.h</filename>. It will include other files from
3219 the <filename>include/yaz</filename> directory, so you'll
3220 probably want to use the -I option of your compiler to tell it
3221 where to find the files. When you run
3222 <literal>make</literal> in the top-level &yaz; directory,
3223 everything you need to create your server is to link with the
3224 <filename>lib/libyaz.la</filename> library.
3227 <sect1 id="server.main">
3228 <title>Your main() Routine</title>
3230 As mentioned, your <function>main()</function> routine can be quite brief.
3231 If you want to initialize global parameters, or read global configuration
3232 tables, this is the place to do it. At the end of the routine, you should
3236 int statserv_main(int argc, char **argv,
3237 bend_initresult *(*bend_init)(bend_initrequest *r),
3238 void (*bend_close)(void *handle));
3241 The third and fourth arguments are pointers to handlers. Handler
3242 <function>bend_init</function> is called whenever the server receives
3243 an Initialize Request, so it serves as a Z39.50 session initializer. The
3244 <function>bend_close</function> handler is called when the session is
3248 <function>statserv_main</function> will establish listening sockets
3249 according to the parameters given. When connection requests are received,
3250 the event handler will typically <function>fork()</function> and
3251 create a sub-process to handle a new connection.
3252 Alternatively the server may be setup to create threads for each
3254 If you do use global variables and forking, you should be aware, then,
3255 that these cannot be shared between associations, unless you explicitly
3256 disable forking by command line parameters.
3259 The server provides a mechanism for controlling some of its behavior
3260 without using command-line options. The function
3263 statserv_options_block *statserv_getcontrol(void);
3266 will return a pointer to a <literal>struct statserv_options_block</literal>
3267 describing the current default settings of the server. The structure
3268 contains these elements:
3271 <term><literal>int dynamic</literal></term>
3273 A boolean value, which determines whether the server
3274 will fork on each incoming request (TRUE), or not (FALSE). Default is
3275 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3280 <term><literal>int threads</literal></term>
3282 A boolean value, which determines whether the server
3283 will create a thread on each incoming request (TRUE), or not (FALSE).
3284 Default is FALSE. This flag is only read by UNIX-based servers
3285 that offer POSIX Threads support.
3286 WIN32-based servers always operate in threaded mode.
3290 <term><literal>int inetd</literal></term>
3292 A boolean value, which determines whether the server
3293 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3297 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3298 <listitem><para>File for diagnostic output ("": stderr).
3302 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3304 Name of file for logging incoming and outgoing APDUs
3305 ("": don't log APDUs, "-":
3306 <literal>stderr</literal>).
3310 <term><literal>char default_listen[1024]</literal></term>
3311 <listitem><para>Same form as the command-line specification of
3312 listener address. "": no default listener address.
3313 Default is to listen at "tcp:@:9999". You can only
3314 specify one default listener address in this fashion.
3318 <term><literal>enum oid_proto default_proto;</literal></term>
3319 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3320 <literal>PROTO_SR</literal>.
3321 Default is <literal>PROTO_Z39_50</literal>.
3325 <term><literal>int idle_timeout;</literal></term>
3326 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3327 no (infinite) timeout. Default is 15 minutes.
3331 <term><literal>int maxrecordsize;</literal></term>
3332 <listitem><para>Maximum permissible record (message) size. Default
3333 is 64 MB. This amount of memory will only be allocated if a
3334 client requests a very large amount of records in one operation
3336 Set it to a lower number if you are worried about resource
3337 consumption on your host system.
3341 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3342 <listitem><para>Passed to the backend when a new connection is received.
3346 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3347 <listitem><para>Set user id to the user specified, after binding
3348 the listener addresses.
3353 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3355 <listitem><para>Pointer to function which is called after the
3356 command line options have been parsed - but before the server
3358 For forked UNIX servers this handler is called in the mother
3359 process; for threaded servers this handler is called in the
3361 The default value of this pointer is NULL in which case it
3362 isn't invoked by the frontend server.
3363 When the server operates as an NT service this handler is called
3364 whenever the service is started.
3369 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3371 <listitem><para>Pointer to function which is called whenever the server
3372 has stopped listening for incoming connections. This function pointer
3373 has a default value of NULL in which case it isn't called.
3374 When the server operates as an NT service this handler is called
3375 whenever the service is stopped.
3379 <term><literal>void *handle</literal></term>
3380 <listitem><para>User defined pointer (default value NULL).
3381 This is a per-server handle that can be used to specify "user-data".
3382 Do not confuse this with the session-handle as returned by bend_init.
3388 The pointer returned by <literal>statserv_getcontrol</literal> points to
3389 a static area. You are allowed to change the contents of the structure,
3390 but the changes will not take effect before you call
3393 void statserv_setcontrol(statserv_options_block *block);
3397 that you should generally update this structure before calling
3398 <function>statserv_main()</function>.
3402 <sect1 id="server.backendfunctions">
3403 <title>The Backend Functions</title>
3405 For each service of the protocol, the backend interface declares one or
3406 two functions. You are required to provide implementations of the
3407 functions representing the services that you wish to implement.
3409 <sect2 id="server.init">
3412 bend_initresult (*bend_init)(bend_initrequest *r);
3415 This handler is called once for each new connection request, after
3416 a new process/thread has been created, and an Initialize Request has
3417 been received from the client. The pointer to the
3418 <function>bend_init</function> handler is passed in the call to
3419 <function>statserv_start</function>.
3422 This handler is also called when operating in SRU mode - when
3423 a connection has been made (even though SRU does not offer
3427 Unlike previous versions of YAZ, the <function>bend_init</function> also
3428 serves as a handler that defines the Z39.50 services that the backend
3429 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3430 including search - and fetch must be specified here in this handler.
3433 The request - and result structures are defined as
3436 typedef struct bend_initrequest
3438 /** \brief user/name/password to be read */
3439 Z_IdAuthentication *auth;
3440 /** \brief encoding stream (for results) */
3442 /** \brief printing stream */
3444 /** \brief decoding stream (use stream for results) */
3446 /** \brief reference ID */
3447 Z_ReferenceId *referenceId;
3448 /** \brief peer address of client */
3451 /** \brief character set and language negotiation
3453 see include/yaz/z-charneg.h
3455 Z_CharSetandLanguageNegotiation *charneg_request;
3457 /** \brief character negotiation response */
3458 Z_External *charneg_response;
3460 /** \brief character set (encoding) for query terms
3462 This is NULL by default. It should be set to the native character
3463 set that the backend assumes for query terms */
3464 char *query_charset;
3466 /** \brief whehter query_charset also applies to recors
3468 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3469 character set as queries. If in doubt, use 0 (No).
3471 int records_in_same_charset;
3473 char *implementation_id;
3474 char *implementation_name;
3475 char *implementation_version;
3477 /** \brief Z39.50 sort handler */
3478 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3479 /** \brief SRU/Z39.50 search handler */
3480 int (*bend_search)(void *handle, bend_search_rr *rr);
3481 /** \brief SRU/Z39.50 fetch handler */
3482 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3483 /** \brief SRU/Z39.50 present handler */
3484 int (*bend_present)(void *handle, bend_present_rr *rr);
3485 /** \brief Z39.50 extended services handler */
3486 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3487 /** \brief Z39.50 delete result set handler */
3488 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3489 /** \brief Z39.50 scan handler */
3490 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3491 /** \brief Z39.50 segment facility handler */
3492 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3493 /** \brief SRU explain handler */
3494 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3495 /** \brief SRU scan handler */
3496 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3497 /** \brief SRU record update handler */
3498 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3500 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3501 int named_result_sets;
3504 typedef struct bend_initresult
3506 int errcode; /* 0==OK */
3507 char *errstring; /* system error string or NULL */
3508 void *handle; /* private handle to the backend module */
3512 In general, the server frontend expects that the
3513 <literal>bend_*result</literal> pointer that you return is valid at
3514 least until the next call to a <literal>bend_* function</literal>.
3515 This applies to all of the functions described herein. The parameter
3516 structure passed to you in the call belongs to the server frontend, and
3517 you should not make assumptions about its contents after the current
3518 function call has completed. In other words, if you want to retain any
3519 of the contents of a request structure, you should copy them.
3522 The <literal>errcode</literal> should be zero if the initialization of
3523 the backend went well. Any other value will be interpreted as an error.
3524 The <literal>errstring</literal> isn't used in the current version, but
3525 one option would be to stick it in the initResponse as a VisibleString.
3526 The <literal>handle</literal> is the most important parameter. It should
3527 be set to some value that uniquely identifies the current session to
3528 the backend implementation. It is used by the frontend server in any
3529 future calls to a backend function.
3530 The typical use is to set it to point to a dynamically allocated state
3531 structure that is private to your backend module.
3534 The <literal>auth</literal> member holds the authentication information
3535 part of the Z39.50 Initialize Request. Interpret this if your serves
3536 requires authentication.
3539 The members <literal>peer_name</literal>,
3540 <literal>implementation_id</literal>,
3541 <literal>implementation_name</literal> and
3542 <literal>implementation_version</literal> holds
3543 DNS of client, ID of implementor, name
3544 of client (Z39.50) implementation - and version.
3547 The <literal>bend_</literal> - members are set to NULL when
3548 <function>bend_init</function> is called. Modify the pointers by
3549 setting them to point to backend functions.
3552 <sect2 id="server.search.retrieve">
3553 <title>Search and Retrieve</title>
3555 We now describe the handlers that are required to support search -
3556 and retrieve. You must support two functions - one for search - and one
3557 for fetch (retrieval of one record). If desirable you can provide a
3558 third handler which is called when a present request is received which
3559 allows you to optimize retrieval of multiple-records.
3562 int (*bend_search) (void *handle, bend_search_rr *rr);
3565 char *setname; /* name to give to this set */
3566 int replace_set; /* replace set, if it already exists */
3567 int num_bases; /* number of databases in list */
3568 char **basenames; /* databases to search */
3569 Z_ReferenceId *referenceId;/* reference ID */
3570 Z_Query *query; /* query structure */
3571 ODR stream; /* encode stream */
3572 ODR decode; /* decode stream */
3573 ODR print; /* print stream */
3575 bend_request request;
3576 bend_association association;
3578 int hits; /* number of hits */
3579 int errcode; /* 0==OK */
3580 char *errstring; /* system error string or NULL */
3581 Z_OtherInformation *search_info; /* additional search info */
3582 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3583 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3584 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3585 int estimated_hit_count; /* if hit count is estimated */
3586 int partial_resultset; /* if result set is partial */
3590 The <function>bend_search</function> handler is a fairly close
3591 approximation of a protocol Z39.50 Search Request - and Response PDUs
3592 The <literal>setname</literal> is the resultSetName from the protocol.
3593 You are required to establish a mapping between the set name and whatever
3594 your backend database likes to use.
3595 Similarly, the <literal>replace_set</literal> is a boolean value
3596 corresponding to the resultSetIndicator field in the protocol.
3597 <literal>num_bases/basenames</literal> is a length of/array of character
3598 pointers to the database names provided by the client.
3599 The <literal>query</literal> is the full query structure as defined in
3600 the protocol ASN.1 specification.
3601 It can be either of the possible query types, and it's up to you to
3602 determine if you can handle the provided query type.
3603 Rather than reproduce the C interface here, we'll refer you to the
3604 structure definitions in the file
3605 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3606 attributeSetId OID of the RPN query, you can either match it against
3607 your own internal tables, or you can use the <link linkend="tools.oid">
3611 The structure contains a number of hits, and an
3612 <literal>errcode/errstring</literal> pair. If an error occurs
3613 during the search, or if you're unhappy with the request, you should
3614 set the errcode to a value from the BIB-1 diagnostic set. The value
3615 will then be returned to the user in a nonsurrogate diagnostic record
3616 in the response. The <literal>errstring</literal>, if provided, will
3617 go in the addinfo field. Look at the protocol definition for the
3618 defined error codes, and the suggested uses of the addinfo field.
3621 The <function>bend_search</function> handler is also called when
3622 the frontend server receives a SRU SearchRetrieveRequest.
3623 For SRU, a CQL query is usually provided by the client.
3624 The CQL query is available as part of <literal>Z_Query</literal>
3625 structure (note that CQL is now part of Z39.50 via an external).
3626 To support CQL in existing implementations that only do Type-1,
3627 we refer to the CQL-to-PQF tool described
3628 <link linkend="cql.to.pqf">here</link>.
3631 To maintain backwards compatibility, the frontend server
3632 of yaz always assume that error codes are BIB-1 diagnostics.
3633 For SRU operation, a Bib-1 diagnostic code is mapped to
3637 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3639 typedef struct bend_fetch_rr {
3640 char *setname; /* set name */
3641 int number; /* record number */
3642 Z_ReferenceId *referenceId;/* reference ID */
3643 Odr_oid *request_format; /* format, transfer syntax (OID) */
3644 Z_RecordComposition *comp; /* Formatting instructions */
3645 ODR stream; /* encoding stream - memory source if req */
3646 ODR print; /* printing stream */
3648 char *basename; /* name of database that provided record */
3649 int len; /* length of record or -1 if structured */
3650 char *record; /* record */
3651 int last_in_set; /* is it? */
3652 Odr_oid *output_format; /* response format/syntax (OID) */
3653 int errcode; /* 0==success */
3654 char *errstring; /* system error string or NULL */
3655 int surrogate_flag; /* surrogate diagnostic */
3656 char *schema; /* string record schema input/output */
3660 The frontend server calls the <function>bend_fetch</function> handler
3661 when it needs database records to fulfill a Z39.50 Search Request, a
3662 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3663 The <literal>setname</literal> is simply the name of the result set
3664 that holds the reference to the desired record.
3665 The <literal>number</literal> is the offset into the set (with 1
3666 being the first record in the set). The <literal>format</literal> field
3667 is the record format requested by the client (See
3668 <xref linkend="tools.oid"/>).
3669 A value of NULL for <literal>format</literal> indicates that the
3670 client did not request a specific format.
3671 The <literal>stream</literal> argument is an &odr; stream which
3672 should be used for allocating space for structured data records.
3673 The stream will be reset when all records have been assembled, and
3674 the response package has been transmitted.
3675 For unstructured data, the backend is responsible for maintaining a
3676 static or dynamic buffer for the record between calls.
3679 If a SRU SearchRetrieveRequest is received by the frontend server,
3680 the <literal>referenceId</literal> is NULL and the
3681 <literal>format</literal> (transfer syntax) is the OID for XML.
3682 The schema for SRU is stored in both the
3683 <literal>Z_RecordComposition</literal>
3684 structure and <literal>schema</literal> (simple string).
3687 In the structure, the <literal>basename</literal> is the name of the
3688 database that holds the
3689 record. <literal>len</literal> is the length of the record returned, in
3690 bytes, and <literal>record</literal> is a pointer to the record.
3691 <literal>last_in_set</literal> should be nonzero only if the record
3692 returned is the last one in the given result set.
3693 <literal>errcode</literal> and <literal>errstring</literal>, if
3694 given, will be interpreted as a global error pertaining to the
3695 set, and will be returned in a non-surrogate-diagnostic.
3696 If you wish to return the error as a surrogate-diagnostic
3697 (local error) you can do this by setting
3698 <literal>surrogate_flag</literal> to 1 also.
3701 If the <literal>len</literal> field has the value -1, then
3702 <literal>record</literal> is assumed to point to a constructed data
3703 type. The <literal>format</literal> field will be used to determine
3704 which encoder should be used to serialize the data.
3708 If your backend generates structured records, it should use
3709 <function>odr_malloc()</function> on the provided stream for allocating
3710 data: This allows the frontend server to keep track of the record sizes.
3714 The <literal>format</literal> field is mapped to an object identifier
3715 in the direct reference of the resulting EXTERNAL representation
3720 The current version of &yaz; only supports the direct reference mode.
3724 int (*bend_present) (void *handle, bend_present_rr *rr);
3727 char *setname; /* set name */
3729 int number; /* record number */
3730 Odr_oid *format; /* format, transfer syntax (OID) */
3731 Z_ReferenceId *referenceId;/* reference ID */
3732 Z_RecordComposition *comp; /* Formatting instructions */
3733 ODR stream; /* encoding stream - memory source if required */
3734 ODR print; /* printing stream */
3735 bend_request request;
3736 bend_association association;
3738 int hits; /* number of hits */
3739 int errcode; /* 0==OK */
3740 char *errstring; /* system error string or NULL */
3744 The <function>bend_present</function> handler is called when
3745 the server receives a Z39.50 Present Request.
3746 The <literal>setname</literal>,
3747 <literal>start</literal> and <literal>number</literal> is the
3748 name of the result set - start position - and number of records to
3749 be retrieved respectively. <literal>format</literal> and
3750 <literal>comp</literal> is the preferred transfer syntax and element
3751 specifications of the present request.
3754 Note that this is handler serves as a supplement for
3755 <function>bend_fetch</function> and need not to be defined in order to
3756 support search - and retrieve.
3759 <sect2 id="server.delete">
3760 <title>Delete</title>
3762 For back-ends that supports delete of a result set only one handler
3766 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3768 typedef struct bend_delete_rr {
3772 Z_ReferenceId *referenceId;
3773 int delete_status; /* status for the whole operation */
3774 int *statuses; /* status each set - indexed as setnames */
3781 The delete set function definition is rather primitive, mostly because
3782 we have had no practical need for it as of yet. If someone wants
3783 to provide a full delete service, we'd be happy to add the
3784 extra parameters that are required. Are there clients out there
3785 that will actually delete sets they no longer need?
3789 <sect2 id="server.scan">
3792 For servers that wish to offer the scan service one handler
3796 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3799 BEND_SCAN_SUCCESS, /* ok */
3800 BEND_SCAN_PARTIAL /* not all entries could be found */
3803 typedef struct bend_scan_rr {
3804 int num_bases; /* number of elements in databaselist */
3805 char **basenames; /* databases to search */
3806 Odr_oid *attributeset;
3807 Z_ReferenceId *referenceId; /* reference ID */
3808 Z_AttributesPlusTerm *term;
3809 ODR stream; /* encoding stream - memory source if required */
3810 ODR print; /* printing stream */
3812 int *step_size; /* step size */
3813 int term_position; /* desired index of term in result list/returned */
3814 int num_entries; /* number of entries requested/returned */
3816 /* scan term entries. The called handler does not have
3817 to allocate this. Size of entries is num_entries (see above) */
3818 struct scan_entry *entries;
3819 bend_scan_status status;
3822 char *scanClause; /* CQL scan clause */
3823 char *setname; /* Scan in result set (NULL if omitted) */
3827 This backend server handles both Z39.50 scan
3828 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3829 Z39.50 Scan , it must check for a non-NULL value of
3830 <literal>scanClause</literal>.
3834 if designed today, it would be a choice using a union or similar,
3835 but that would break binary compatibility with existing servers.
3840 <sect1 id="server.invocation">
3841 <title>Application Invocation</title>
3843 The finished application has the following
3844 invocation syntax (by way of <function>statserv_main()</function>):
3852 A listener specification consists of a transport mode followed by a
3853 colon (:) followed by a listener address. The transport mode is
3854 either <literal>tcp</literal>, <literal>unix:</literal> or
3855 <literal>ssl</literal>.
3858 For TCP and SSL, an address has the form
3861 hostname | IP-number [: portnumber]
3864 The port number defaults to 210 (standard Z39.50 port).
3867 For UNIX, the address is the filename of socket.
3870 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3871 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3872 IPV4 binding as well (bindv6only=0),
3873 The special hostname <literal>@4</literal> binds to
3874 <literal>INADDR_ANY</literal> (IPV4 only listener).
3875 The special hostname <literal>@6</literal> binds to
3876 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3878 <example id="server.example.running.unix">
3879 <title>Running the GFS on Unix</title>
3881 Assuming the server application <replaceable>appname</replaceable> is
3882 started as root, the following will make it listen on port 210.
3883 The server will change identity to <literal>nobody</literal>
3884 and write its log to <filename>/var/log/app.log</filename>.
3886 application -l /var/log/app.log -u nobody tcp:@:210
3890 The server will accept Z39.50 requests and offer SRU service on port 210.
3893 <example id="server.example.apache.sru">
3894 <title>Setting up Apache as SRU Frontend</title>
3896 If you use <ulink url="&url.apache;">Apache</ulink>
3897 as your public web server and want to offer HTTP port 80
3898 access to the YAZ server on 210, you can use the
3899 <ulink url="&url.apache.directive.proxypass;">
3900 <literal>ProxyPass</literal></ulink>
3902 If you have virtual host
3903 <literal>srw.mydomain</literal> you can use the following directives
3904 in Apache's httpd.conf:
3907 ErrorLog /home/srw/logs/error_log
3908 TransferLog /home/srw/logs/access_log
3909 ProxyPass / http://srw.mydomain:210/
3914 The above for the Apache 1.3 series.
3917 <example id="server.example.local.access">
3918 <title>Running a server with local access only</title>
3920 Servers that is only being accessed from the local host should listen
3921 on UNIX file socket rather than a Internet socket. To listen on
3922 <filename>/tmp/mysocket</filename> start the server as follows:
3924 application unix:/tmp/mysocket
3929 <sect1 id="server.vhosts">
3930 <title>GFS Configuration and Virtual Hosts</title>
3935 <title>The Z39.50 ASN.1 Module</title>
3936 <sect1 id="asn.introduction">
3937 <title>Introduction</title>
3939 The &asn; module provides you with a set of C struct definitions for the
3940 various PDUs of the Z39.50 protocol, as well as for the complex types
3941 appearing within the PDUs. For the primitive data types, the C
3942 representation often takes the form of an ordinary C language type,
3943 such as <literal>Odr_int</literal> which is equivalent to an integral
3944 C integer. For ASN.1 constructs that have no direct
3945 representation in C, such as general octet strings and bit strings,
3946 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3947 provides auxiliary definitions.
3950 The &asn; module is located in sub directory <filename>z39.50</filename>.
3951 There you'll find C files that implements encoders and decoders for the
3952 Z39.50 types. You'll also find the protocol definitions:
3953 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3957 <sect1 id="asn.preparing">
3958 <title>Preparing PDUs</title>
3960 A structure representing a complex ASN.1 type doesn't in itself contain the
3961 members of that type. Instead, the structure contains
3962 <emphasis>pointers</emphasis> to the members of the type.
3963 This is necessary, in part, to allow a mechanism for specifying which
3964 of the optional structure (SEQUENCE) members are present, and which
3965 are not. It follows that you will need to somehow provide space for
3966 the individual members of the structure, and set the pointers to
3967 refer to the members.
3970 The conversion routines don't care how you allocate and maintain your
3971 C structures - they just follow the pointers that you provide.
3972 Depending on the complexity of your application, and your personal
3973 taste, there are at least three different approaches that you may take
3974 when you allocate the structures.
3977 You can use static or automatic local variables in the function that
3978 prepares the PDU. This is a simple approach, and it provides the most
3979 efficient form of memory management. While it works well for flat
3980 PDUs like the InitReqest, it will generally not be sufficient for say,
3981 the generation of an arbitrarily complex RPN query structure.
3984 You can individually create the structure and its members using the
3985 <function>malloc(2)</function> function. If you want to ensure that
3986 the data is freed when it is no longer needed, you will have to
3987 define a function that individually releases each member of a
3988 structure before freeing the structure itself.
3991 You can use the <function>odr_malloc()</function> function (see
3992 <xref linkend="odr.use"/> for details). When you use
3993 <function>odr_malloc()</function>, you can release all of the
3994 allocated data in a single operation, independent of any pointers and
3995 relations between the data. <function>odr_malloc()</function> is based on a
3996 "nibble-memory"
3997 scheme, in which large portions of memory are allocated, and then
3998 gradually handed out with each call to <function>odr_malloc()</function>.
3999 The next time you call <function>odr_reset()</function>, all of the
4000 memory allocated since the last call is recycled for future use (actually,
4001 it is placed on a free-list).
4004 You can combine all of the methods described here. This will often be
4005 the most practical approach. For instance, you might use
4006 <function>odr_malloc()</function> to allocate an entire structure and
4007 some of its elements, while you leave other elements pointing to global
4008 or per-session default variables.
4011 The &asn; module provides an important aid in creating new PDUs. For
4012 each of the PDU types (say, <function>Z_InitRequest</function>), a
4013 function is provided that allocates and initializes an instance of
4014 that PDU type for you. In the case of the InitRequest, the function is
4015 simply named <function>zget_InitRequest()</function>, and it sets up
4016 reasonable default value for all of the mandatory members. The optional
4017 members are generally initialized to null pointers. This last aspect
4018 is very important: it ensures that if the PDU definitions are
4019 extended after you finish your implementation (to accommodate
4020 new versions of the protocol, say), you won't get into trouble with
4021 uninitialized pointers in your structures. The functions use
4022 <function>odr_malloc()</function> to
4023 allocate the PDUs and its members, so you can free everything again with a
4024 single call to <function>odr_reset()</function>. We strongly recommend
4025 that you use the <literal>zget_*</literal>
4026 functions whenever you are preparing a PDU (in a C++ API, the
4027 <literal>zget_</literal>
4028 functions would probably be promoted to constructors for the
4032 The prototype for the individual PDU types generally look like this:
4035 Z_<type> *zget_<type>(ODR o);
4041 Z_InitRequest *zget_InitRequest(ODR o);
4044 The &odr; handle should generally be your encoding stream, but it
4048 As well as the individual PDU functions, a function
4049 <function>zget_APDU()</function> is provided, which allocates
4050 a top-level Z-APDU of the type requested:
4053 Z_APDU *zget_APDU(ODR o, int which);
4056 The <varname>which</varname> parameter is (of course) the discriminator
4057 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
4058 All of the interface described here is provided by the &asn; module, and
4059 you access it through the <filename>proto.h</filename> header file.
4062 <sect1 id="asn.external">
4063 <title>EXTERNAL Data</title>
4065 In order to achieve extensibility and adaptability to different
4066 application domains, the new version of the protocol defines many
4067 structures outside of the main ASN.1 specification, referencing them
4068 through ASN.1 EXTERNAL constructs. To simplify the construction and
4069 access to the externally referenced data, the &asn; module defines a
4070 specialized version of the EXTERNAL construct, called
4071 <literal>Z_External</literal>.It is defined thus:
4074 typedef struct Z_External
4076 Odr_oid *direct_reference;
4077 int *indirect_reference;
4082 Z_External_single = 0,
4084 Z_External_arbitrary,
4086 /* Specific types */
4088 Z_External_explainRecord,
4089 Z_External_resourceReport1,
4090 Z_External_resourceReport2
4098 Odr_any *single_ASN1_type;
4099 Odr_oct *octet_aligned;
4100 Odr_bitmask *arbitrary;
4102 /* Specific types */
4104 Z_ExplainRecord *explainRecord;
4105 Z_ResourceReport1 *resourceReport1;
4106 Z_ResourceReport2 *resourceReport2;
4114 When decoding, the &asn; module will attempt to determine which
4115 syntax describes the data by looking at the reference fields
4116 (currently only the direct-reference). For ASN.1 structured data, you
4117 need only consult the <literal>which</literal> field to determine the
4118 type of data. You can the access the data directly through the union.
4119 When constructing data for encoding, you set the union pointer to point
4120 to the data, and set the <literal>which</literal> field accordingly.
4121 Remember also to set the direct (or indirect) reference to the correct
4122 OID for the data type.
4123 For non-ASN.1 data such as MARC records, use the
4124 <literal>octet_aligned</literal> arm of the union.
4127 Some servers return ASN.1 structured data values (eg. database
4128 records) as BER-encoded records placed in the
4129 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
4130 The ASN-module will <emphasis>not</emphasis> automatically decode
4131 these records. To help you decode the records in the application, the
4135 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
4138 Can be used to retrieve information about the known, external data
4139 types. The function return a pointer to a static area, or NULL, if no
4140 match for the given direct reference is found. The
4141 <literal>Z_ext_typeent</literal>
4145 typedef struct Z_ext_typeent
4147 int oid[OID_SIZE]; /* the direct-reference OID. */
4148 int what; /* discriminator value for the external CHOICE */
4149 Odr_fun fun; /* decoder function */
4153 The <literal>what</literal> member contains the
4154 <literal>Z_External</literal> union discriminator value for the
4155 given type: For the SUTRS record syntax, the value would be
4156 <literal>Z_External_sutrs</literal>.
4157 The <literal>fun</literal> member contains a pointer to the
4158 function which encodes/decodes the given type. Again, for the SUTRS
4159 record syntax, the value of <literal>fun</literal> would be
4160 <literal>z_SUTRS</literal> (a function pointer).
4163 If you receive an EXTERNAL which contains an octet-string value that
4164 you suspect of being an ASN.1-structured data value, you can use
4165 <literal>z_ext_gettypebyref</literal> to look for the provided
4167 If the return value is different from NULL, you can use the provided
4168 function to decode the BER string (see <xref linkend="odr.use"/>
4172 If you want to <emphasis>send</emphasis> EXTERNALs containing
4173 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4174 is possible too. However, on the encoding phase, it requires a somewhat
4175 involved juggling around of the various buffers involved.
4178 If you need to add new, externally defined data types, you must update
4179 the struct above, in the source file <filename>prt-ext.h</filename>, as
4180 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4181 When changing the latter, remember to update both the
4182 <literal>arm</literal> arrary and the list
4183 <literal>type_table</literal>, which drives the CHOICE biasing that
4184 is necessary to tell the different, structured types apart
4189 Eventually, the EXTERNAL processing will most likely
4190 automatically insert the correct OIDs or indirect-refs. First,
4191 however, we need to determine how application-context management
4192 (specifically the presentation-context-list) should fit into the
4197 <sect1 id="asn.pdu">
4198 <title>PDU Contents Table</title>
4200 We include, for reference, a listing of the fields of each top-level
4201 PDU, as well as their default settings.
4203 <table frame="top" id="asn.default.initialize.request">
4204 <title>Default settings for PDU Initialize Request</title>
4206 <colspec colwidth="7*" colname="field"></colspec>
4207 <colspec colwidth="5*" colname="type"></colspec>
4208 <colspec colwidth="7*" colname="value"></colspec>
4211 <entry>Field</entry>
4213 <entry>Default Value</entry>
4218 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4221 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4224 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4227 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4230 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4233 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4236 implementationId</entry><entry>char*</entry><entry>"81"
4239 implementationName</entry><entry>char*</entry><entry>"YAZ"
4242 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4245 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4248 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4253 <table frame="top" id="asn.default.initialize.response">
4254 <title>Default settings for PDU Initialize Response</title>
4256 <colspec colwidth="7*" colname="field"></colspec>
4257 <colspec colwidth="5*" colname="type"></colspec>
4258 <colspec colwidth="7*" colname="value"></colspec>
4261 <entry>Field</entry>
4263 <entry>Default Value</entry>
4268 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4271 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4274 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4277 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4280 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4283 result</entry><entry>Odr_bool</entry><entry>TRUE
4286 implementationId</entry><entry>char*</entry><entry>"id)"
4289 implementationName</entry><entry>char*</entry><entry>"YAZ"
4292 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4295 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4298 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4303 <table frame="top" id="asn.default.search.request">
4304 <title>Default settings for PDU Search Request</title>
4306 <colspec colwidth="7*" colname="field"></colspec>
4307 <colspec colwidth="5*" colname="type"></colspec>
4308 <colspec colwidth="7*" colname="value"></colspec>
4311 <entry>Field</entry>
4313 <entry>Default Value</entry>
4318 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4321 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4324 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4327 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4330 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4333 resultSetName</entry><entry>char *</entry><entry>"default"
4336 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4339 databaseNames</entry><entry>char **</entry><entry>NULL
4342 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4346 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4350 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4353 query</entry><entry>Z_Query</entry><entry>NULL
4356 additionalSearchInfo</entry><entry>Z_OtherInformation
4360 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4365 <table frame="top" id="asn.default.search.response">
4366 <title>Default settings for PDU Search Response</title>
4368 <colspec colwidth="7*" colname="field"></colspec>
4369 <colspec colwidth="5*" colname="type"></colspec>
4370 <colspec colwidth="7*" colname="value"></colspec>
4373 <entry>Field</entry>
4375 <entry>Default Value</entry>
4380 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4383 resultCount</entry><entry>Odr_int</entry><entry>0
4386 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4389 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4392 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4395 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4398 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4401 records</entry><entry>Z_Records</entry><entry>NULL
4404 additionalSearchInfo</entry>
4405 <entry>Z_OtherInformation</entry><entry>NULL
4408 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4413 <table frame="top" id="asn.default.present.request">
4414 <title>Default settings for PDU Present Request</title>
4416 <colspec colwidth="7*" colname="field"></colspec>
4417 <colspec colwidth="5*" colname="type"></colspec>
4418 <colspec colwidth="7*" colname="value"></colspec>
4421 <entry>Field</entry>
4423 <entry>Default Value</entry>
4428 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4431 resultSetId</entry><entry>char*</entry><entry>"default"
4434 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4437 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4440 num_ranges</entry><entry>Odr_int</entry><entry>0
4443 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4446 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4449 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4452 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4455 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4458 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4461 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4466 <table frame="top" id="asn.default.present.response">
4467 <title>Default settings for PDU Present Response</title>
4469 <colspec colwidth="7*" colname="field"></colspec>
4470 <colspec colwidth="5*" colname="type"></colspec>
4471 <colspec colwidth="7*" colname="value"></colspec>
4474 <entry>Field</entry>
4476 <entry>Default Value</entry>
4481 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4484 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4487 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4490 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4493 records</entry><entry>Z_Records</entry><entry>NULL
4496 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4501 <table frame="top" id="asn.default.delete.result.set.request">
4502 <title>Default settings for Delete Result Set Request</title>
4504 <colspec colwidth="7*" colname="field"></colspec>
4505 <colspec colwidth="5*" colname="type"></colspec>
4506 <colspec colwidth="7*" colname="value"></colspec>
4509 <entry>Field</entry>
4511 <entry>Default Value</entry>
4515 <row><entry>referenceId
4516 </entry><entry>Z_ReferenceId</entry><entry>NULL
4519 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4522 num_ids</entry><entry>Odr_int</entry><entry>0
4525 resultSetList</entry><entry>char**</entry><entry>NULL
4528 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4533 <table frame="top" id="asn.default.delete.result.set.response">
4534 <title>Default settings for Delete Result Set Response</title>
4536 <colspec colwidth="7*" colname="field"></colspec>
4537 <colspec colwidth="5*" colname="type"></colspec>
4538 <colspec colwidth="7*" colname="value"></colspec>
4541 <entry>Field</entry>
4543 <entry>Default Value</entry>
4548 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4551 deleteOperationStatus</entry><entry>Odr_int</entry>
4552 <entry>Z_DeleteStatus_success</entry></row>
4554 num_statuses</entry><entry>Odr_int</entry><entry>0
4557 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4560 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4563 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4566 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4569 deleteMessage</entry><entry>char*</entry><entry>NULL
4572 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4577 <table frame="top" id="asn.default.scan.request">
4578 <title>Default settings for Scan Request</title>
4580 <colspec colwidth="7*" colname="field"></colspec>
4581 <colspec colwidth="5*" colname="type"></colspec>
4582 <colspec colwidth="7*" colname="value"></colspec>
4585 <entry>Field</entry>
4587 <entry>Default Value</entry>
4592 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4595 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4598 databaseNames</entry><entry>char**</entry><entry>NULL
4601 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4604 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4605 </entry><entry>NULL</entry></row>
4607 stepSize</entry><entry>Odr_int</entry><entry>NULL
4610 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4613 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4616 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4621 <table frame="top" id="asn.default.scan.response">
4622 <title>Default settings for Scan Response</title>
4624 <colspec colwidth="7*" colname="field"></colspec>
4625 <colspec colwidth="5*" colname="type"></colspec>
4626 <colspec colwidth="7*" colname="value"></colspec>
4629 <entry>Field</entry>
4631 <entry>Default Value</entry>
4636 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4639 stepSize</entry><entry>Odr_int</entry><entry>NULL
4642 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4645 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4648 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4651 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4654 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4657 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4662 <table frame="top" id="asn.default.trigger.resource.control.request">
4663 <title>Default settings for Trigger Resource Control Request</title>
4665 <colspec colwidth="7*" colname="field"></colspec>
4666 <colspec colwidth="5*" colname="type"></colspec>
4667 <colspec colwidth="7*" colname="value"></colspec>
4670 <entry>Field</entry>
4672 <entry>Default Value</entry>
4677 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4680 requestedAction</entry><entry>Odr_int</entry><entry>
4681 Z_TriggerResourceCtrl_resou..
4684 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4687 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4690 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4695 <table frame="top" id="asn.default.resource.control.request">
4696 <title>Default settings for Resource Control Request</title>
4698 <colspec colwidth="7*" colname="field"></colspec>
4699 <colspec colwidth="5*" colname="type"></colspec>
4700 <colspec colwidth="7*" colname="value"></colspec>
4703 <entry>Field</entry>
4705 <entry>Default Value</entry>
4710 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4713 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4716 resourceReport</entry><entry>Z_External</entry><entry>NULL
4719 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4722 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4725 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4728 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4733 <table frame="top" id="asn.default.resource.control.response">
4734 <title>Default settings for Resource Control Response</title>
4736 <colspec colwidth="7*" colname="field"></colspec>
4737 <colspec colwidth="5*" colname="type"></colspec>
4738 <colspec colwidth="7*" colname="value"></colspec>
4741 <entry>Field</entry>
4743 <entry>Default Value</entry>
4748 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4751 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4754 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4757 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4762 <table frame="top" id="asn.default.access.control.request">
4763 <title>Default settings for Access Control Request</title>
4765 <colspec colwidth="7*" colname="field"></colspec>
4766 <colspec colwidth="5*" colname="type"></colspec>
4767 <colspec colwidth="7*" colname="value"></colspec>
4770 <entry>Field</entry>
4772 <entry>Default Value</entry>
4777 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4780 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4783 u</entry><entry>union</entry><entry>NULL
4786 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4791 <table frame="top" id="asn.default.access.control.response">
4792 <title>Default settings for Access Control Response</title>
4794 <colspec colwidth="7*" colname="field"></colspec>
4795 <colspec colwidth="5*" colname="type"></colspec>
4796 <colspec colwidth="7*" colname="value"></colspec>
4799 <entry>Field</entry>
4801 <entry>Default Value</entry>
4806 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4809 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4812 u</entry><entry>union</entry><entry>NULL
4815 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4818 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4823 <table frame="top" id="asn.default.segment">
4824 <title>Default settings for Segment</title>
4826 <colspec colwidth="7*" colname="field"></colspec>
4827 <colspec colwidth="5*" colname="type"></colspec>
4828 <colspec colwidth="7*" colname="value"></colspec>
4831 <entry>Field</entry>
4833 <entry>Default Value</entry>
4838 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4841 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4844 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4847 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4849 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4854 <table frame="top" id="asn.default.close">
4855 <title>Default settings for Close</title>
4857 <colspec colwidth="7*" colname="field"></colspec>
4858 <colspec colwidth="5*" colname="type"></colspec>
4859 <colspec colwidth="7*" colname="value"></colspec>
4862 <entry>Field</entry>
4864 <entry>Default Value</entry>
4869 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4872 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4875 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4878 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4881 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4884 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4892 <title>SOAP and SRU</title>
4893 <sect1 id="soap.introduction">
4894 <title>Introduction</title>
4896 &yaz; uses a very simple implementation of
4897 <ulink url="&url.soap;">SOAP</ulink> that only,
4898 currenly, supports what is sufficient to offer SRU SOAP functionality.
4899 The implementation uses the
4900 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4901 libxml2 to encode and decode SOAP packages.
4904 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4905 simple C structs to represent SOAP packages as well as
4909 <sect1 id="soap.http">
4912 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4913 relatively easy to change that.
4916 The following definition of <literal>Z_GDU</literal> (Generic Data
4917 Unit) allows for both HTTP and Z39.50 in one packet.
4920 #include <yaz/zgdu.h>
4922 #define Z_GDU_Z3950 1
4923 #define Z_GDU_HTTP_Request 2
4924 #define Z_GDU_HTTP_Response 3
4929 Z_HTTP_Request *HTTP_Request;
4930 Z_HTTP_Response *HTTP_Response;
4935 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4936 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4938 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4939 is the HTTP Request and Response respectively.
4942 <sect1 id="soap.xml">
4943 <title>SOAP Packages</title>
4945 Every SOAP package in &yaz; is represented as follows:
4947 #include <yaz/soap.h>
4961 #define Z_SOAP_fault 1
4962 #define Z_SOAP_generic 2
4963 #define Z_SOAP_error 3
4967 Z_SOAP_Fault *fault;
4968 Z_SOAP_Generic *generic;
4969 Z_SOAP_Fault *soap_error;
4976 The <literal>fault</literal> and <literal>soap_error</literal>
4977 arms represent both a SOAP fault - struct
4978 <literal>Z_SOAP_Fault</literal>. Any other generic
4979 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
4982 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
4983 is the namespace for SOAP itself and reflects the SOAP
4984 version. For version 1.1 it is
4985 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
4986 for version 1.2 it is
4987 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
4990 int z_soap_codec(ODR o, Z_SOAP **pp,
4991 char **content_buf, int *content_len,
4992 Z_SOAP_Handler *handlers);
4995 The <literal>content_buf</literal> and <literal>content_len</literal>
4996 is XML buffer and length of buffer respectively.
4999 The <literal>handlers</literal> is a list of SOAP codec
5000 handlers - one handler for each service namespace. For SRU SOAP, the
5001 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
5004 When decoding, the <function>z_soap_codec</function>
5005 inspects the XML content
5006 and tries to match one of the services namespaces of the
5007 supplied handlers. If there is a match a handler function
5008 is invoked which decodes that particular SOAP package.
5009 If successful, the returned <literal>Z_SOAP</literal> package will be
5010 of type <literal>Z_SOAP_Generic</literal>.
5011 Member <literal>no</literal> is
5012 set the offset of handler that matched; <literal>ns</literal>
5013 is set to namespace of matching handler; the void pointer
5014 <literal>p</literal> is set to the C data structure assocatiated
5018 When a NULL namespace is met (member <literal>ns</literal> bwlow),
5019 that specifies end-of-list.
5022 Each handler is defined as follows:
5030 The <literal>ns</literal> is namespace of service associated with
5031 handler <literal>f</literal>. <literal>client_data</literal>
5032 is user-defined data which is passed to handler.
5035 The prototype for a SOAP service handler is:
5037 int handler(ODR o, void * ptr, void **handler_data,
5038 void *client_data, const char *ns);
5040 The <parameter>o</parameter> specifies the mode (decode/encode)
5041 as usual. The second argument, <parameter>ptr</parameter>,
5042 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
5043 and is a pointer to the <literal>Body</literal> element
5044 of the SOAP package. The <parameter>handler_data</parameter>
5045 is an opaque pointer to a C definitions associated with the
5046 SOAP service. <parameter>client_data</parameter> is the pointer
5047 which was set as part of the <literal>Z_SOAP_handler</literal>.
5048 Finally, <parameter>ns</parameter> the service namespace.
5051 <sect1 id="soap.srw">
5054 SRU SOAP is just one implementation of a SOAP handler as described
5055 in the previous section.
5056 The encoder/decoder handler for SRU is defined as
5059 #include <yaz/srw.h>
5061 int yaz_srw_codec(ODR o, void * pptr,
5062 Z_SRW_GDU **handler_data,
5063 void *client_data, const char *ns);
5065 Here, <literal>Z_SRW_GDU</literal> is either
5066 searchRetrieveRequest or a searchRetrieveResponse.
5070 The xQuery and xSortKeys are not handled yet by
5071 the SRW implementation of &yaz;. Explain is also missing.
5072 Future versions of &yaz; will include these features.
5076 The definition of searchRetrieveRequest is:
5080 #define Z_SRW_query_type_cql 1
5081 #define Z_SRW_query_type_xcql 2
5082 #define Z_SRW_query_type_pqf 3
5090 #define Z_SRW_sort_type_none 1
5091 #define Z_SRW_sort_type_sort 2
5092 #define Z_SRW_sort_type_xSort 3
5100 int *maximumRecords;
5102 char *recordPacking;
5104 } Z_SRW_searchRetrieveRequest;
5106 Please observe that data of type xsd:string is represented
5107 as a char pointer (<literal>char *</literal>). A null pointer
5108 means that the element is absent.
5109 Data of type xsd:integer is representd as a pointer to
5110 an int (<literal>int *</literal>). Again, a null pointer
5111 us used for absent elements.
5114 The SearchRetrieveResponse has the following definition.
5117 int * numberOfRecords;
5119 int * resultSetIdleTime;
5121 Z_SRW_record *records;
5124 Z_SRW_diagnostic *diagnostics;
5125 int num_diagnostics;
5126 int *nextRecordPosition;
5127 } Z_SRW_searchRetrieveResponse;
5129 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
5130 is number of returned records and diagnostics respectively and also
5131 correspond to the "size of" arrays <literal>records</literal>
5132 and <literal>diagnostics</literal>.
5135 A retrieval record is defined as follows:
5139 char *recordData_buf;
5141 int *recordPosition;
5144 The record data is defined as a buffer of some length so that
5145 data can be of any type. SRW 1.0 currenly doesn't allow for this
5146 (only XML), but future versions might do.
5149 And, a diagnostic as:
5159 <chapter id="tools">
5160 <title>Supporting Tools</title>
5162 In support of the service API - primarily the ASN module, which
5163 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5164 a collection of tools that support the development of applications.
5166 <sect1 id="tools.query">
5167 <title>Query Syntax Parsers</title>
5169 Since the type-1 (RPN) query structure has no direct, useful string
5170 representation, every origin application needs to provide some form of
5171 mapping from a local query notation or representation to a
5172 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5173 construct the query manually, perhaps using
5174 <function>odr_malloc()</function> to simplify memory management.
5175 The &yaz; distribution includes three separate, query-generating tools
5176 that may be of use to you.
5179 <title>Prefix Query Format</title>
5181 Since RPN or reverse polish notation is really just a fancy way of
5182 describing a suffix notation format (operator follows operands), it
5183 would seem that the confusion is total when we now introduce a prefix
5184 notation for RPN. The reason is one of simple laziness - it's somewhat
5185 simpler to interpret a prefix format, and this utility was designed
5186 for maximum simplicity, to provide a baseline representation for use
5187 in simple test applications and scripting environments (like Tcl). The
5188 demonstration client included with YAZ uses the PQF.
5192 The PQF have been adopted by other parties developing Z39.50
5193 software. It is often referred to as Prefix Query Notation
5198 The PQF is defined by the pquery module in the YAZ library.
5199 There are two sets of function that have similar behavior. First
5200 set operates on a PQF parser handle, second set doesn't. First set
5201 set of functions are more flexible than the second set. Second set
5202 is obsolete and is only provided to ensure backwards compatibility.
5205 First set of functions all operate on a PQF parser handle:
5208 #include <yaz/pquery.h>
5210 YAZ_PQF_Parser yaz_pqf_create(void);
5212 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5214 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5216 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5217 Odr_oid **attributeSetId, const char *qbuf);
5219 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5222 A PQF parser is created and destructed by functions
5223 <function>yaz_pqf_create</function> and
5224 <function>yaz_pqf_destroy</function> respectively.
5225 Function <function>yaz_pqf_parse</function> parses query given
5226 by string <literal>qbuf</literal>. If parsing was successful,
5227 a Z39.50 RPN Query is returned which is created using ODR stream
5228 <literal>o</literal>. If parsing failed, a NULL pointer is
5230 Function <function>yaz_pqf_scan</function> takes a scan query in
5231 <literal>qbuf</literal>. If parsing was successful, the function
5232 returns attributes plus term pointer and modifies
5233 <literal>attributeSetId</literal> to hold attribute set for the
5234 scan request - both allocated using ODR stream <literal>o</literal>.
5235 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5236 Error information for bad queries can be obtained by a call to
5237 <function>yaz_pqf_error</function> which returns an error code and
5238 modifies <literal>*msg</literal> to point to an error description,
5239 and modifies <literal>*off</literal> to the offset within last
5240 query were parsing failed.
5243 The second set of functions are declared as follows:
5246 #include <yaz/pquery.h>
5248 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5250 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5251 Odr_oid **attributeSetP, const char *qbuf);
5253 int p_query_attset(const char *arg);
5256 The function <function>p_query_rpn()</function> takes as arguments an
5257 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5258 to provide a memory source (the structure created is released on
5259 the next call to <function>odr_reset()</function> on the stream), a
5260 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5261 <token>PROTO_SR</token>), an attribute set reference, and
5262 finally a null-terminated string holding the query string.
5265 If the parse went well, <function>p_query_rpn()</function> returns a
5266 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5267 placed directly into a <literal>Z_SearchRequest</literal>.
5268 If parsing failed, due to syntax error, a NULL pointer is returned.
5271 The <literal>p_query_attset</literal> specifies which attribute set
5272 to use if the query doesn't specify one by the
5273 <literal>@attrset</literal> operator.
5274 The <literal>p_query_attset</literal> returns 0 if the argument is a
5275 valid attribute set specifier; otherwise the function returns -1.
5278 The grammar of the PQF is as follows:
5281 query ::= top-set query-struct.
5283 top-set ::= [ '@attrset' string ]
5285 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5287 attr-spec ::= '@attr' [ string ] string query-struct
5289 complex ::= operator query-struct query-struct.
5291 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5293 simple ::= result-set | term.
5295 result-set ::= '@set' string.
5299 proximity ::= exclusion distance ordered relation which-code unit-code.
5301 exclusion ::= '1' | '0' | 'void'.
5303 distance ::= integer.
5305 ordered ::= '1' | '0'.
5307 relation ::= integer.
5309 which-code ::= 'known' | 'private' | integer.
5311 unit-code ::= integer.
5313 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5316 You will note that the syntax above is a fairly faithful
5317 representation of RPN, except for the Attribute, which has been
5318 moved a step away from the term, allowing you to associate one or more
5319 attributes with an entire query structure. The parser will
5320 automatically apply the given attributes to each term as required.
5323 The @attr operator is followed by an attribute specification
5324 (<literal>attr-spec</literal> above). The specification consists
5325 of an optional attribute set, an attribute type-value pair and
5326 a sub-query. The attribute type-value pair is packed in one string:
5327 an attribute type, an equals sign, and an attribute value, like this:
5328 <literal>@attr 1=1003</literal>.
5329 The type is always an integer but the value may be either an
5330 integer or a string (if it doesn't start with a digit character).
5331 A string attribute-value is encoded as a Type-1 ``complex''
5332 attribute with the list of values containing the single string
5333 specified, and including no semantic indicators.
5336 Version 3 of the Z39.50 specification defines various encoding of terms.
5337 Use <literal>@term </literal> <replaceable>type</replaceable>
5338 <replaceable>string</replaceable>,
5339 where type is one of: <literal>general</literal>,
5340 <literal>numeric</literal> or <literal>string</literal>
5341 (for InternationalString).
5342 If no term type has been given, the <literal>general</literal> form
5343 is used. This is the only encoding allowed in both versions 2 and 3
5344 of the Z39.50 standard.
5346 <sect3 id="PQF-prox">
5347 <title>Using Proximity Operators with PQF</title>
5350 This is an advanced topic, describing how to construct
5351 queries that make very specific requirements on the
5352 relative location of their operands.
5353 You may wish to skip this section and go straight to
5354 <link linkend="pqf-examples">the example PQF queries</link>.
5359 Most Z39.50 servers do not support proximity searching, or
5360 support only a small subset of the full functionality that
5361 can be expressed using the PQF proximity operator. Be
5362 aware that the ability to <emphasis>express</emphasis> a
5363 query in PQF is no guarantee that any given server will
5364 be able to <emphasis>execute</emphasis> it.
5370 The proximity operator <literal>@prox</literal> is a special
5371 and more restrictive version of the conjunction operator
5372 <literal>@and</literal>. Its semantics are described in
5373 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5374 can be read on-line at
5375 <ulink url="&url.z39.50.proximity;"/>
5378 In PQF, the proximity operation is represented by a sequence
5381 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5383 in which the meanings of the parameters are as described in in
5384 the standard, and they can take the following values:
5387 <formalpara><title>exclusion</title>
5389 0 = false (i.e. the proximity condition specified by the
5390 remaining parameters must be satisfied) or
5391 1 = true (the proximity condition specified by the
5392 remaining parameters must <emphasis>not</emphasis> be
5398 <formalpara><title>distance</title><para>
5399 An integer specifying the difference between the locations
5400 of the operands: e.g. two adjacent words would have
5401 distance=1 since their locations differ by one unit.
5403 </formalpara></listitem>
5405 <formalpara><title>ordered</title><para>
5406 1 = ordered (the operands must occur in the order the
5407 query specifies them) or
5408 0 = unordered (they may appear in either order).
5413 <formalpara><title>relation</title><para>
5414 Recognised values are
5416 2 (lessThanOrEqual),
5418 4 (greaterThanOrEqual),
5425 <formalpara><title>which-code</title><para>
5426 <literal>known</literal>
5428 <literal>k</literal>
5429 (the unit-code parameter is taken from the well-known list
5430 of alternatives described in below) or
5431 <literal>private</literal>
5433 <literal>p</literal>
5434 (the unit-code paramater has semantics specific to an
5435 out-of-band agreement such as a profile).
5440 <formalpara><title>unit-code</title><para>
5441 If the which-code parameter is <literal>known</literal>
5442 then the recognised values are
5452 10 (elementType) and
5454 If which-code is <literal>private</literal> then the
5455 acceptable values are determined by the profile.
5460 (The numeric values of the relation and well-known unit-code
5461 parameters are taken straight from
5462 <ulink url="&url.z39.50.proximity.asn1;"
5463 >the ASN.1</ulink> of the proximity structure in the standard.)
5466 <sect3 id="pqf-examples">
5467 <title>PQF queries</title>
5468 <example id="example.pqf.simple.terms">
5469 <title>PQF queries using simple terms</title>
5478 <example id="pqf.example.pqf.boolean.operators">
5479 <title>PQF boolean operators</title>
5482 @or "dylan" "zimmerman"
5484 @and @or dylan zimmerman when
5486 @and when @or dylan zimmerman
5490 <example id="example.pqf.result.sets">
5491 <title>PQF references to result sets</title>
5496 @and @set seta @set setb
5500 <example id="example.pqf.attributes">
5501 <title>Attributes for terms</title>
5506 @attr 1=4 @attr 4=1 "self portrait"
5508 @attrset exp1 @attr 1=1 CategoryList
5510 @attr gils 1=2008 Copenhagen
5512 @attr 1=/book/title computer
5516 <example id="example.pqf.proximity">
5517 <title>PQF Proximity queries</title>
5520 @prox 0 3 1 2 k 2 dylan zimmerman
5522 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5523 distance, ordered, relation, which-code and unit-code, in that
5527 <para>exclusion = 0: the proximity condition must hold</para>
5530 <para>distance = 3: the terms must be three units apart</para>
5534 ordered = 1: they must occur in the order they are specified
5539 relation = 2: lessThanOrEqual (to the distance of 3 units)
5544 which-code is ``known'', so the standard unit-codes are used
5548 <para>unit-code = 2: word.</para>
5551 So the whole proximity query means that the words
5552 <literal>dylan</literal> and <literal>zimmerman</literal> must
5553 both occur in the record, in that order, differing in position
5554 by three or fewer words (i.e. with two or fewer words between
5555 them.) The query would find ``Bob Dylan, aka. Robert
5556 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5557 since the distance in this case is four.
5560 <example id="example.pqf.search.term.type">
5561 <title>PQF specification of search term type</title>
5564 @term string "a UTF-8 string, maybe?"
5568 <example id="example.pqf.mixed.queries">
5569 <title>PQF mixed queries</title>
5572 @or @and bob dylan @set Result-1
5574 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5576 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5578 The last of these examples is a spatial search: in
5579 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5580 >the GILS attribute set</ulink>,
5582 2038 indicates West Bounding Coordinate and
5583 2030 indicates East Bounding Coordinate,
5584 so the query is for areas extending from -114 degrees
5585 to no more than -109 degrees.
5590 <sect2 id="CCL"><title>CCL</title>
5592 Not all users enjoy typing in prefix query structures and numerical
5593 attribute values, even in a minimalistic test client. In the library
5594 world, the more intuitive Common Command Language - CCL (ISO 8777)
5595 has enjoyed some popularity - especially before the widespread
5596 availability of graphical interfaces. It is still useful in
5597 applications where you for some reason or other need to provide a
5598 symbolic language for expressing boolean query structures.
5600 <sect3 id="ccl.syntax">
5601 <title>CCL Syntax</title>
5603 The CCL parser obeys the following grammar for the FIND argument.
5604 The syntax is annotated by in the lines prefixed by
5605 <literal>--</literal>.
5608 CCL-Find ::= CCL-Find Op Elements
5611 Op ::= "and" | "or" | "not"
5612 -- The above means that Elements are separated by boolean operators.
5614 Elements ::= '(' CCL-Find ')'
5617 | Qualifiers Relation Terms
5618 | Qualifiers Relation '(' CCL-Find ')'
5619 | Qualifiers '=' string '-' string
5620 -- Elements is either a recursive definition, a result set reference, a
5621 -- list of terms, qualifiers followed by terms, qualifiers followed
5622 -- by a recursive definition or qualifiers in a range (lower - upper).
5624 Set ::= 'set' = string
5625 -- Reference to a result set
5627 Terms ::= Terms Prox Term
5629 -- Proximity of terms.
5631 Term ::= Term string
5633 -- This basically means that a term may include a blank
5635 Qualifiers ::= Qualifiers ',' string
5637 -- Qualifiers is a list of strings separated by comma
5639 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5640 -- Relational operators. This really doesn't follow the ISO8777
5644 -- Proximity operator
5647 <example id="example.ccl.queries">
5648 <title>CCL queries</title>
5650 The following queries are all valid:
5661 (dylan and bob) or set=1
5670 Assuming that the qualifiers <literal>ti</literal>,
5671 <literal>au</literal>
5672 and <literal>date</literal> are defined we may use:
5677 au=(bob dylan and slow train coming)
5679 date>1980 and (ti=((self portrait)))
5683 <sect3 id="ccl.qualifiers">
5684 <title>CCL Qualifiers</title>
5686 Qualifiers are used to direct the search to a particular searchable
5687 index, such as title (ti) and author indexes (au). The CCL standard
5688 itself doesn't specify a particular set of qualifiers, but it does
5689 suggest a few short-hand notations. You can customize the CCL parser
5690 to support a particular set of qualifiers to reflect the current target
5691 profile. Traditionally, a qualifier would map to a particular
5692 use-attribute within the BIB-1 attribute set. It is also
5693 possible to set other attributes, such as the structure
5697 A CCL profile is a set of predefined CCL qualifiers that may be
5698 read from a file or set in the CCL API.
5699 The YAZ client reads its CCL qualifiers from a file named
5700 <filename>default.bib</filename>. There are four types of
5701 lines in a CCL profile: qualifier specification,
5702 qualifier alias, comments and directives.
5704 <sect4 id="ccl.qualifier.specification">
5705 <title>Qualifier specification</title>
5707 A qualifier specification is of the form:
5710 <replaceable>qualifier-name</replaceable>
5711 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5712 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5715 where <replaceable>qualifier-name</replaceable> is the name of the
5716 qualifier to be used (eg. <literal>ti</literal>),
5717 <replaceable>type</replaceable> is attribute type in the attribute
5718 set (Bib-1 is used if no attribute set is given) and
5719 <replaceable>val</replaceable> is attribute value.
5720 The <replaceable>type</replaceable> can be specified as an
5721 integer or as it be specified either as a single-letter:
5722 <literal>u</literal> for use,
5723 <literal>r</literal> for relation,<literal>p</literal> for position,
5724 <literal>s</literal> for structure,<literal>t</literal> for truncation
5725 or <literal>c</literal> for completeness.
5726 The attributes for the special qualifier name <literal>term</literal>
5727 are used when no CCL qualifier is given in a query.
5728 <table id="ccl.common.bib1.attributes">
5729 <title>Common Bib-1 attributes</title>
5731 <colspec colwidth="2*" colname="type"></colspec>
5732 <colspec colwidth="9*" colname="description"></colspec>
5736 <entry>Description</entry>
5741 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5743 Use attribute (1). Common use attributes are
5744 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5745 62 Subject, 1003 Author), 1016 Any. Specify value
5750 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5752 Relation attribute (2). Common values are
5753 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5754 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5758 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5760 Position attribute (3). Values: 1 first in field, 2
5761 first in any subfield, 3 any position in field.
5765 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5767 Structure attribute (4). Values: 1 phrase, 2 word,
5768 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5769 101 name (norm), 102 name (un), 103 structure, 104 urx,
5770 105 free-form-text, 106 document-text, 107 local-number,
5771 108 string, 109 numeric string.
5775 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5777 Truncation attribute (5). Values: 1 right, 2 left,
5778 3 left& right, 100 none, 101 process #, 102 regular-1,
5779 103 regular-2, 104 CCL.
5783 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5785 Completeness attribute (6). Values: 1 incomplete subfield,
5786 2 complete subfield, 3 complete field.
5794 Refer to <xref linkend="bib1"/> or the complete
5795 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5798 It is also possible to specify non-numeric attribute values,
5799 which are used in combination with certain types.
5800 The special combinations are:
5801 <table id="ccl.special.attribute.combos">
5802 <title>Special attribute combos</title>
5804 <colspec colwidth="2*" colname="name"></colspec>
5805 <colspec colwidth="9*" colname="description"></colspec>
5809 <entry>Description</entry>
5814 <entry><literal>s=pw</literal></entry>
5816 The structure is set to either word or phrase depending
5817 on the number of tokens in a term (phrase-word).
5821 <entry><literal>s=al</literal></entry>
5823 Each token in the term is ANDed. (and-list).
5824 This does not set the structure at all.
5827 <row><entry><literal>s=ol</literal></entry>
5829 Each token in the term is ORed. (or-list).
5830 This does not set the structure at all.
5833 <row><entry><literal>s=ag</literal></entry>
5835 Tokens that appears as phrases (with blank in them) gets
5836 structure phrase attached (4=1). Tokens that appear to be words
5837 gets structure word attached (4=2). Phrases and words are
5838 ANDed. This is a variant of s=al and s=pw, with the main
5839 difference that words are not split (with operator AND)
5840 but instead kept in one RPN token. This facility appeared
5844 <row><entry><literal>s=sl</literal></entry>
5846 Tokens are split into sub-phrases of all combinations - in order.
5847 This facility appeared in YAZ 5.14.0.
5850 <row><entry><literal>r=o</literal></entry>
5852 Allows ranges and the operators greather-than, less-than, ...
5854 This sets Bib-1 relation attribute accordingly (relation
5855 ordered). A query construct is only treated as a range if
5856 dash is used and that is surrounded by white-space. So
5857 <literal>-1980</literal> is treated as term
5858 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5859 If <literal>- 1980</literal> is used, however, that is
5863 <row><entry><literal>r=r</literal></entry>
5865 Similar to <literal>r=o</literal> but assumes that terms
5866 are non-negative (not prefixed with <literal>-</literal>).
5867 Thus, a dash will always be treated as a range.
5868 The construct <literal>1980-1990</literal> is
5869 treated as a range with <literal>r=r</literal> but as a
5870 single term <literal>"1980-1990"</literal> with
5871 <literal>r=o</literal>. The special attribute
5872 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5875 <row><entry><literal>r=omiteq</literal></entry>
5877 This will omit relation=equals (@attr 2=3) when r=o / r=r
5878 is used. This is useful for servers that somehow breaks
5879 when an explicit relation=equals is used. Omitting the
5880 relation is usually safe because "equals" is the default
5881 behavior. This tweak was added in YAZ version 5.1.2.
5884 <row><entry><literal>t=l</literal></entry>
5886 Allows term to be left-truncated.
5887 If term is of the form <literal>?x</literal>, the resulting
5888 Type-1 term is <literal>x</literal> and truncation is left.
5891 <row><entry><literal>t=r</literal></entry>
5893 Allows term to be right-truncated.
5894 If term is of the form <literal>x?</literal>, the resulting
5895 Type-1 term is <literal>x</literal> and truncation is right.
5898 <row><entry><literal>t=n</literal></entry>
5900 If term is does not include <literal>?</literal>, the
5901 truncation attribute is set to none (100).
5904 <row><entry><literal>t=b</literal></entry>
5906 Allows term to be both left&right truncated.
5907 If term is of the form <literal>?x?</literal>, the
5908 resulting term is <literal>x</literal> and trunctation is
5909 set to both left&right.
5912 <row><entry><literal>t=x</literal></entry>
5914 Allows masking anywhere in a term, thus fully supporting
5915 # (mask one character) and ? (zero or more of any).
5916 If masking is used, trunction is set to 102 (regexp-1 in term)
5917 and the term is converted accordingly to a regular expression.
5920 <row><entry><literal>t=z</literal></entry>
5922 Allows masking anywhere in a term, thus fully supporting
5923 # (mask one character) and ? (zero or more of any).
5924 If masking is used, trunction is set to 104 (Z39.58 in term)
5925 and the term is converted accordingly to Z39.58 masking term -
5926 actually the same truncation as CCL itself.
5933 <example id="example.ccl.profile">
5934 <title>CCL profile</title>
5936 Consider the following definition:
5946 <literal>ti</literal> and <literal>au</literal> both set
5947 structure attribute to phrase (s=1).
5948 <literal>ti</literal>
5949 sets the use-attribute to 4. <literal>au</literal> sets the
5951 When no qualifiers are used in the query the structure-attribute is
5952 set to free-form-text (105) (rule for <literal>term</literal>).
5953 The <literal>date</literal> sets the relation attribute to
5954 the relation used in the CCL query and sets the use attribute
5958 You can combine attributes. To Search for "ranked title" you
5961 ti,ranked=knuth computer
5963 which will set relation=ranked, use=title, structure=phrase.
5970 is a valid query. But
5978 <sect4 id="ccl.qualifier.alias">
5979 <title>Qualifier alias</title>
5981 A qualifier alias is of the form:
5984 <replaceable>q</replaceable>
5985 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
5988 which declares <replaceable>q</replaceable> to
5989 be an alias for <replaceable>q1</replaceable>,
5990 <replaceable>q2</replaceable>... such that the CCL
5991 query <replaceable>q=x</replaceable> is equivalent to
5992 <replaceable>q1=x or q2=x or ...</replaceable>.
5995 <sect4 id="ccl.comments">
5996 <title>Comments</title>
5998 Lines with white space or lines that begin with
5999 character <literal>#</literal> are treated as comments.
6002 <sect4 id="ccl.directives">
6003 <title>Directives</title>
6005 Directive specifications takes the form
6007 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
6009 <table id="ccl.directives.table">
6010 <title>CCL directives</title>
6012 <colspec colwidth="2*" colname="name"></colspec>
6013 <colspec colwidth="8*" colname="description"></colspec>
6014 <colspec colwidth="1*" colname="default"></colspec>
6018 <entry>Description</entry>
6019 <entry>Default</entry>
6024 <entry>truncation</entry>
6025 <entry>Truncation character</entry>
6026 <entry><literal>?</literal></entry>
6030 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
6031 <entry><literal>#</literal></entry>
6034 <entry>field</entry>
6035 <entry>Specifies how multiple fields are to be
6036 combined. There are two modes: <literal>or</literal>:
6037 multiple qualifier fields are ORed,
6038 <literal>merge</literal>: attributes for the qualifier
6039 fields are merged and assigned to one term.
6041 <entry><literal>merge</literal></entry>
6045 <entry>Specifies if CCL operators and qualifiers should be
6046 compared with case sensitivity or not. Specify 1 for
6047 case sensitive; 0 for case insensitive.</entry>
6048 <entry><literal>1</literal></entry>
6052 <entry>Specifies token for CCL operator AND.</entry>
6053 <entry><literal>and</literal></entry>
6057 <entry>Specifies token for CCL operator OR.</entry>
6058 <entry><literal>or</literal></entry>
6062 <entry>Specifies token for CCL operator NOT.</entry>
6063 <entry><literal>not</literal></entry>
6067 <entry>Specifies token for CCL operator SET.</entry>
6068 <entry><literal>set</literal></entry>
6075 <sect3 id="ccl.api">
6076 <title>CCL API</title>
6078 All public definitions can be found in the header file
6079 <filename>ccl.h</filename>. A profile identifier is of type
6080 <literal>CCL_bibset</literal>. A profile must be created with the call
6081 to the function <function>ccl_qual_mk</function> which returns a profile
6082 handle of type <literal>CCL_bibset</literal>.
6085 To read a file containing qualifier definitions the function
6086 <function>ccl_qual_file</function> may be convenient. This function
6087 takes an already opened <literal>FILE</literal> handle pointer as
6088 argument along with a <literal>CCL_bibset</literal> handle.
6091 To parse a simple string with a FIND query use the function
6094 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
6095 int *error, int *pos);
6098 which takes the CCL profile (<literal>bibset</literal>) and query
6099 (<literal>str</literal>) as input. Upon successful completion the RPN
6100 tree is returned. If an error occur, such as a syntax error, the integer
6101 pointed to by <literal>error</literal> holds the error code and
6102 <literal>pos</literal> holds the offset inside query string in which
6106 An English representation of the error may be obtained by calling
6107 the <literal>ccl_err_msg</literal> function. The error codes are
6108 listed in <filename>ccl.h</filename>.
6111 To convert the CCL RPN tree (type
6112 <literal>struct ccl_rpn_node *</literal>)
6113 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
6114 must be used. This function which is part of YAZ is implemented in
6115 <filename>yaz-ccl.c</filename>.
6116 After calling this function the CCL RPN tree is probably no longer
6117 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
6120 A CCL profile may be destroyed by calling the
6121 <function>ccl_qual_rm</function> function.
6124 The token names for the CCL operators may be changed by setting the
6125 globals (all type <literal>char *</literal>)
6126 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
6127 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
6128 An operator may have aliases, i.e. there may be more than one name for
6129 the operator. To do this, separate each alias with a space character.
6136 <ulink url="&url.cql;">CQL</ulink>
6137 - Common Query Language - was defined for the
6138 <ulink url="&url.sru;">SRU</ulink> protocol.
6139 In many ways CQL has a similar syntax to CCL.
6140 The objective of CQL is different. Where CCL aims to be
6141 an end-user language, CQL is <emphasis>the</emphasis> protocol
6142 query language for SRU.
6146 If you are new to CQL, read the
6147 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6151 The CQL parser in &yaz; provides the following:
6155 It parses and validates a CQL query.
6160 It generates a C structure that allows you to convert
6161 a CQL query to some other query language, such as SQL.
6166 The parser converts a valid CQL query to PQF, thus providing a
6167 way to use CQL for both SRU servers and Z39.50 targets at the
6173 The parser converts CQL to XCQL.
6174 XCQL is an XML representation of CQL.
6175 XCQL is part of the SRU specification. However, since SRU
6176 supports CQL only, we don't expect XCQL to be widely used.
6177 Furthermore, CQL has the advantage over XCQL that it is
6183 <sect3 id="cql.parsing">
6184 <title>CQL parsing</title>
6186 A CQL parser is represented by the <literal>CQL_parser</literal>
6187 handle. Its contents should be considered &yaz; internal (private).
6189 #include <yaz/cql.h>
6191 typedef struct cql_parser *CQL_parser;
6193 CQL_parser cql_parser_create(void);
6194 void cql_parser_destroy(CQL_parser cp);
6196 A parser is created by <function>cql_parser_create</function> and
6197 is destroyed by <function>cql_parser_destroy</function>.
6200 To parse a CQL query string, the following function
6203 int cql_parser_string(CQL_parser cp, const char *str);
6205 A CQL query is parsed by the <function>cql_parser_string</function>
6206 which takes a query <parameter>str</parameter>.
6207 If the query was valid (no syntax errors), then zero is returned;
6208 otherwise -1 is returned to indicate a syntax error.
6212 int cql_parser_stream(CQL_parser cp,
6213 int (*getbyte)(void *client_data),
6214 void (*ungetbyte)(int b, void *client_data),
6217 int cql_parser_stdio(CQL_parser cp, FILE *f);
6219 The functions <function>cql_parser_stream</function> and
6220 <function>cql_parser_stdio</function> parses a CQL query
6221 - just like <function>cql_parser_string</function>.
6222 The only difference is that the CQL query can be
6223 fed to the parser in different ways.
6224 The <function>cql_parser_stream</function> uses a generic
6225 byte stream as input. The <function>cql_parser_stdio</function>
6226 uses a <literal>FILE</literal> handle which is opened for reading.
6229 <sect3 id="cql.tree">
6230 <title>CQL tree</title>
6232 The the query string is valid, the CQL parser
6233 generates a tree representing the structure of the
6238 struct cql_node *cql_parser_result(CQL_parser cp);
6240 <function>cql_parser_result</function> returns the
6241 a pointer to the root node of the resulting tree.
6244 Each node in a CQL tree is represented by a
6245 <literal>struct cql_node</literal>.
6246 It is defined as follows:
6248 #define CQL_NODE_ST 1
6249 #define CQL_NODE_BOOL 2
6250 #define CQL_NODE_SORT 3
6260 struct cql_node *modifiers;
6264 struct cql_node *left;
6265 struct cql_node *right;
6266 struct cql_node *modifiers;
6270 struct cql_node *next;
6271 struct cql_node *modifiers;
6272 struct cql_node *search;
6277 There are three node types: search term (ST), boolean (BOOL)
6279 A modifier is treated as a search term too.
6282 The search term node has five members:
6286 <literal>index</literal>: index for search term.
6287 If an index is unspecified for a search term,
6288 <literal>index</literal> will be NULL.
6293 <literal>index_uri</literal>: index URi for search term
6294 or NULL if none could be resolved for the index.
6299 <literal>term</literal>: the search term itself.
6304 <literal>relation</literal>: relation for search term.
6309 <literal>relation_uri</literal>: relation URI for search term.
6314 <literal>modifiers</literal>: relation modifiers for search
6315 term. The <literal>modifiers</literal> list itself of cql_nodes
6316 each of type <literal>ST</literal>.
6322 The boolean node represents <literal>and</literal>,
6323 <literal>or</literal>, <literal>not</literal> +
6328 <literal>left</literal> and <literal>right</literal>: left
6329 - and right operand respectively.
6334 <literal>modifiers</literal>: proximity arguments.
6340 The sort node represents both the SORTBY clause.
6343 <sect3 id="cql.to.pqf">
6344 <title>CQL to PQF conversion</title>
6346 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6347 that the resulting RPN depends on the Z39.50 target
6348 capabilities (combinations of supported attributes).
6349 In addition, the CQL and SRU operates on index prefixes
6350 (URI or strings), whereas the RPN uses Object Identifiers
6354 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6355 type. It represents a particular mapping between CQL and RPN.
6356 This handle is created and destroyed by the functions:
6358 cql_transform_t cql_transform_open_FILE (FILE *f);
6359 cql_transform_t cql_transform_open_fname(const char *fname);
6360 void cql_transform_close(cql_transform_t ct);
6362 The first two functions create a tranformation handle from
6363 either an already open FILE or from a filename respectively.
6366 The handle is destroyed by <function>cql_transform_close</function>
6367 in which case no further reference of the handle is allowed.
6370 When a <literal>cql_transform_t</literal> handle has been created
6371 you can convert to RPN.
6373 int cql_transform_buf(cql_transform_t ct,
6374 struct cql_node *cn, char *out, int max);
6376 This function converts the CQL tree <literal>cn</literal>
6377 using handle <literal>ct</literal>.
6378 For the resulting PQF, you supply a buffer <literal>out</literal>
6379 which must be able to hold at at least <literal>max</literal>
6383 If conversion failed, <function>cql_transform_buf</function>
6384 returns a non-zero SRU error code; otherwise zero is returned
6385 (conversion successful). The meanings of the numeric error
6386 codes are listed in the SRU specification somewhere (no
6387 direct link anymore).
6390 If conversion fails, more information can be obtained by calling
6392 int cql_transform_error(cql_transform_t ct, char **addinfop);
6394 This function returns the most recently returned numeric
6395 error-code and sets the string-pointer at
6396 <literal>*addinfop</literal> to point to a string containing
6397 additional information about the error that occurred: for
6398 example, if the error code is 15 (``Illegal or unsupported context
6399 set''), the additional information is the name of the requested
6400 context set that was not recognised.
6403 The SRU error-codes may be translated into brief human-readable
6404 error messages using
6406 const char *cql_strerror(int code);
6410 If you wish to be able to produce a PQF result in a different
6411 way, there are two alternatives.
6413 void cql_transform_pr(cql_transform_t ct,
6414 struct cql_node *cn,
6415 void (*pr)(const char *buf, void *client_data),
6418 int cql_transform_FILE(cql_transform_t ct,
6419 struct cql_node *cn, FILE *f);
6421 The former function produces output to a user-defined
6422 output stream. The latter writes the result to an already
6423 open <literal>FILE</literal>.
6426 <sect3 id="cql.to.rpn">
6427 <title>Specification of CQL to RPN mappings</title>
6429 The file supplied to functions
6430 <function>cql_transform_open_FILE</function>,
6431 <function>cql_transform_open_fname</function> follows
6432 a structure found in many Unix utilities.
6433 It consists of mapping specifications - one per line.
6434 Lines starting with <literal>#</literal> are ignored (comments).
6437 Each line is of the form
6439 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6443 An RPN pattern is a simple attribute list. Each attribute pair
6446 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6448 The attribute <replaceable>set</replaceable> is optional.
6449 The <replaceable>type</replaceable> is the attribute type,
6450 <replaceable>value</replaceable> the attribute value.
6453 The character <literal>*</literal> (asterisk) has special meaning
6454 when used in the RPN pattern.
6455 Each occurrence of <literal>*</literal> is substituted with the
6456 CQL matching name (index, relation, qualifier etc).
6457 This facility can be used to copy a CQL name verbatim to the RPN result.
6460 The following CQL patterns are recognized:
6464 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6468 This pattern is invoked when a CQL index, such as
6469 dc.title is converted. <replaceable>set</replaceable>
6470 and <replaceable>name</replaceable> are the context set and index
6472 Typically, the RPN specifies an equivalent use attribute.
6475 For terms not bound by an index the pattern
6476 <literal>index.cql.serverChoice</literal> is used.
6477 Here, the prefix <literal>cql</literal> is defined as
6478 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6479 If this pattern is not defined, the mapping will fail.
6483 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6484 is used when no other index pattern is matched.
6490 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6495 For backwards compatibility, this is recognised as a synonym of
6496 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6502 <literal>relation.</literal><replaceable>relation</replaceable>
6506 This pattern specifies how a CQL relation is mapped to RPN.
6507 <replaceable>pattern</replaceable> is name of relation
6508 operator. Since <literal>=</literal> is used as
6509 separator between CQL pattern and RPN, CQL relations
6510 including <literal>=</literal> cannot be
6511 used directly. To avoid a conflict, the names
6512 <literal>ge</literal>,
6513 <literal>eq</literal>,
6514 <literal>le</literal>,
6515 must be used for CQL operators, greater-than-or-equal,
6516 equal, less-than-or-equal respectively.
6517 The RPN pattern is supposed to include a relation attribute.
6520 For terms not bound by a relation, the pattern
6521 <literal>relation.scr</literal> is used. If the pattern
6522 is not defined, the mapping will fail.
6525 The special pattern, <literal>relation.*</literal> is used
6526 when no other relation pattern is matched.
6532 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6536 This pattern specifies how a CQL relation modifier is mapped to RPN.
6537 The RPN pattern is usually a relation attribute.
6543 <literal>structure.</literal><replaceable>type</replaceable>
6547 This pattern specifies how a CQL structure is mapped to RPN.
6548 Note that this CQL pattern is somewhat to similar to
6549 CQL pattern <literal>relation</literal>.
6550 The <replaceable>type</replaceable> is a CQL relation.
6553 The pattern, <literal>structure.*</literal> is used
6554 when no other structure pattern is matched.
6555 Usually, the RPN equivalent specifies a structure attribute.
6561 <literal>position.</literal><replaceable>type</replaceable>
6565 This pattern specifies how the anchor (position) of
6566 CQL is mapped to RPN.
6567 The <replaceable>type</replaceable> is one
6568 of <literal>first</literal>, <literal>any</literal>,
6569 <literal>last</literal>, <literal>firstAndLast</literal>.
6572 The pattern, <literal>position.*</literal> is used
6573 when no other position pattern is matched.
6579 <literal>set.</literal><replaceable>prefix</replaceable>
6583 This specification defines a CQL context set for a given prefix.
6584 The value on the right hand side is the URI for the set -
6585 <emphasis>not</emphasis> RPN. All prefixes used in
6586 index patterns must be defined this way.
6592 <literal>set</literal>
6596 This specification defines a default CQL context set for index names.
6597 The value on the right hand side is the URI for the set.
6603 <example id="example.cql.to.rpn.mapping">
6604 <title>CQL to RPN mapping file</title>
6606 This simple file defines two context sets, three indexes and three
6607 relations, a position pattern and a default structure.
6609 <programlisting><![CDATA[
6610 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6611 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6613 index.cql.serverChoice = 1=1016
6614 index.dc.title = 1=4
6615 index.dc.subject = 1=21
6621 position.any = 3=3 6=1
6627 With the mappings above, the CQL query
6631 is converted to the PQF:
6633 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6635 by rules <literal>index.cql.serverChoice</literal>,
6636 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6637 <literal>position.any</literal>.
6644 is rejected, since <literal>position.right</literal> is
6650 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6654 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6658 <example id="example.cql.to.rpn.string">
6659 <title>CQL to RPN string attributes</title>
6661 In this example we allow any index to be passed to RPN as
6664 <programlisting><![CDATA[
6665 # Identifiers for prefixes used in this file. (index.*)
6666 set.cql = info:srw/cql-context-set/1/cql-v1.1
6667 set.rpn = http://bogus/rpn
6668 set = http://bogus/rpn
6670 # The default index when none is specified by the query
6671 index.cql.serverChoice = 1=any
6680 The <literal>http://bogus/rpn</literal> context set is also the default
6681 so we can make queries such as
6685 which is converted to
6687 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6691 <example id="example.cql.to.rpn.bathprofile">
6692 <title>CQL to RPN using Bath Profile</title>
6694 The file <filename>etc/pqf.properties</filename> has mappings from
6695 the Bath Profile and Dublin Core to RPN.
6696 If YAZ is installed as a package it's usually located
6697 in <filename>/usr/share/yaz/etc</filename> and part of the
6698 development package, such as <literal>libyaz-dev</literal>.
6702 <sect3 id="cql.xcql">
6703 <title>CQL to XCQL conversion</title>
6705 Conversion from CQL to XCQL is trivial and does not
6706 require a mapping to be defined.
6707 There three functions to choose from depending on the
6708 way you wish to store the resulting output (XML buffer
6711 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6712 void cql_to_xml(struct cql_node *cn,
6713 void (*pr)(const char *buf, void *client_data),
6715 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6717 Function <function>cql_to_xml_buf</function> converts
6718 to XCQL and stores result in a user supplied buffer of a given
6722 <function>cql_to_xml</function> writes the result in
6723 a user defined output stream.
6724 <function>cql_to_xml_stdio</function> writes to a
6728 <sect3 id="rpn.to.cql">
6729 <title>PQF to CQL conversion</title>
6731 Conversion from PQF to CQL is offered by the two functions shown
6732 below. The former uses a generic stream for result. The latter
6733 puts result in a WRBUF (string container).
6735 #include <yaz/rpn2cql.h>
6737 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6738 void (*pr)(const char *buf, void *client_data),
6742 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6746 The configuration is the same as used in CQL to PQF conversions.
6751 <sect1 id="tools.oid">
6752 <title>Object Identifiers</title>
6754 The basic YAZ representation of an OID is an array of integers,
6755 terminated with the value -1. This integer is of type
6756 <literal>Odr_oid</literal>.
6759 Fundamental OID operations and the type <literal>Odr_oid</literal>
6760 are defined in <filename>yaz/oid_util.h</filename>.
6763 An OID can either be declared as a automatic variable or it can
6764 allocated using the memory utilities or ODR/NMEM. It's
6765 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6767 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6769 We can create an OID for the Bib-1 attribute set with:
6771 Odr_oid bib1[OID_SIZE];
6783 And OID may also be filled from a string-based representation using
6784 dots (.). This is achieved by function
6786 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6788 This functions returns 0 if name could be converted; -1 otherwise.
6790 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6792 We can fill the Bib-1 attribute set OID easier with:
6794 Odr_oid bib1[OID_SIZE];
6795 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6800 We can also allocate an OID dynamically on a ODR stream with:
6802 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6804 This creates an OID from string-based representation using dots.
6805 This function take an &odr; stream as parameter. This stream is used to
6806 allocate memory for the data elements, which is released on a
6807 subsequent call to <function>odr_reset()</function> on that stream.
6809 <example id="tools.oid.bib1.3">
6810 <title>Using odr_getoidbystr</title>
6812 We can create a OID for the Bib-1 attribute set with:
6814 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6821 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6823 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6824 converts an OID to the string-based representation using dots.
6825 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6826 string and must be at least <literal>OID_STR_MAX</literal> in size.
6829 OIDs can be copied with <function>oid_oidcpy</function> which takes
6830 two OID lists as arguments. Alternativly, an OID copy can be allocated
6831 on a ODR stream with:
6833 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6837 OIDs can be compared with <function>oid_oidcmp</function> which returns
6838 zero if the two OIDs provided are identical; non-zero otherwise.
6840 <sect2 id="tools.oid.database">
6841 <title>OID database</title>
6843 From YAZ version 3 and later, the oident system has been replaced
6844 by an OID database. OID database is a misnomer .. the old odient
6845 system was also a database.
6848 The OID database is really just a map between named Object Identifiers
6849 (string) and their OID raw equivalents. Most operations either
6850 convert from string to OID or other way around.
6853 Unfortunately, whenever we supply a string we must also specify the
6854 <emphasis>OID class</emphasis>. The class is necessary because some
6855 strings correspond to multiple OIDs. An example of such a string is
6856 <literal>Bib-1</literal> which may either be an attribute-set
6857 or a diagnostic-set.
6860 Applications using the YAZ database should include
6861 <filename>yaz/oid_db.h</filename>.
6864 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6865 Actually that's a pointer. You need not think deal with that.
6866 YAZ has a built-in database which can be considered "constant" for
6868 We can get hold that by using function <function>yaz_oid_std</function>.
6871 All functions with prefix <function>yaz_string_to_oid</function>
6872 converts from class + string to OID. We have variants of this
6873 operation due to different memory allocation strategies.
6876 All functions with prefix
6877 <function>yaz_oid_to_string</function> converts from OID to string
6880 <example id="tools.oid.bib1.4">
6881 <title>Create OID with YAZ DB</title>
6883 We can create an OID for the Bib-1 attribute set on the ODR stream
6887 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6889 This is more complex than using <function>odr_getoidbystr</function>.
6890 You would only use <function>yaz_string_to_oid_odr</function> when the
6891 string (here Bib-1) is supplied by a user or configuration.
6895 <sect2 id="tools.oid.std">
6896 <title>Standard OIDs</title>
6898 All the object identifers in the standard OID database as returned
6899 by <function>yaz_oid_std</function> can referenced directly in a
6900 program as a constant OID.
6901 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6902 followed by OID class (lowercase) - then by OID name (normalized and
6906 See <xref linkend="list-oids"/> for list of all object identifiers
6908 These are declared in <filename>yaz/oid_std.h</filename> but are
6909 included by <filename>yaz/oid_db.h</filename> as well.
6911 <example id="tools.oid.bib1.5">
6912 <title>Use a built-in OID</title>
6914 We can allocate our own OID filled with the constant OID for
6917 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6923 <sect1 id="tools.nmem">
6924 <title>Nibble Memory</title>
6926 Sometimes when you need to allocate and construct a large,
6927 interconnected complex of structures, it can be a bit of a pain to
6928 release the associated memory again. For the structures describing the
6929 Z39.50 PDUs and related structures, it is convenient to use the
6930 memory-management system of the &odr; subsystem (see
6931 <xref linkend="odr.use"/>). However, in some circumstances
6932 where you might otherwise benefit from using a simple nibble memory
6933 management system, it may be impractical to use
6934 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6935 For this purpose, the memory manager which also supports the &odr;
6936 streams is made available in the NMEM module. The external interface
6937 to this module is given in the <filename>nmem.h</filename> file.
6940 The following prototypes are given:
6943 NMEM nmem_create(void);
6944 void nmem_destroy(NMEM n);
6945 void *nmem_malloc(NMEM n, size_t size);
6946 void nmem_reset(NMEM n);
6947 size_t nmem_total(NMEM n);
6948 void nmem_init(void);
6949 void nmem_exit(void);
6952 The <function>nmem_create()</function> function returns a pointer to a
6953 memory control handle, which can be released again by
6954 <function>nmem_destroy()</function> when no longer needed.
6955 The function <function>nmem_malloc()</function> allocates a block of
6956 memory of the requested size. A call to <function>nmem_reset()</function>
6957 or <function>nmem_destroy()</function> will release all memory allocated
6958 on the handle since it was created (or since the last call to
6959 <function>nmem_reset()</function>. The function
6960 <function>nmem_total()</function> returns the number of bytes currently
6961 allocated on the handle.
6964 The nibble memory pool is shared amongst threads. POSIX
6965 mutex'es and WIN32 Critical sections are introduced to keep the
6966 module thread safe. Function <function>nmem_init()</function>
6967 initializes the nibble memory library and it is called automatically
6968 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6969 function <function>DllMain</function> to achieve this. You should
6970 <emphasis>not</emphasis> call <function>nmem_init</function> or
6971 <function>nmem_exit</function> unless you're absolute sure what
6972 you're doing. Note that in previous &yaz; versions you'd have to call
6973 <function>nmem_init</function> yourself.
6976 <sect1 id="tools.log">
6979 &yaz; has evolved a fairly complex log system which should be useful both
6980 for debugging &yaz; itself, debugging applications that use &yaz;, and for
6981 production use of those applications.
6984 The log functions are declared in header <filename>yaz/log.h</filename>
6985 and implemented in <filename>src/log.c</filename>.
6986 Due to name clash with syslog and some math utilities the logging
6987 interface has been modified as of YAZ 2.0.29. The obsolete interface
6988 is still available if in header file <filename>yaz/log.h</filename>.
6989 The key points of the interface are:
6992 void yaz_log(int level, const char *fmt, ...)
6993 void yaz_log_init(int level, const char *prefix, const char *name);
6994 void yaz_log_init_file(const char *fname);
6995 void yaz_log_init_level(int level);
6996 void yaz_log_init_prefix(const char *prefix);
6997 void yaz_log_time_format(const char *fmt);
6998 void yaz_log_init_max_size(int mx);
7000 int yaz_log_mask_str(const char *str);
7001 int yaz_log_module_level(const char *name);
7004 The reason for the whole log module is the <function>yaz_log</function>
7005 function. It takes a bitmask indicating the log levels, a
7006 <literal>printf</literal>-like format string, and a variable number of
7010 The <literal>log level</literal> is a bit mask, that says on which level(s)
7011 the log entry should be made, and optionally set some behaviour of the
7012 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
7013 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
7014 that modify the way the log entry is written:<literal>YLOG_ERRNO,
7015 YLOG_NOTIME, YLOG_FLUSH</literal>.
7016 Most of the rest of the bits are deprecated, and should not be used. Use
7017 the dynamic log levels instead.
7020 Applications that use &yaz;, should not use the LOG_LOG for ordinary
7021 messages, but should make use of the dynamic loglevel system. This consists
7022 of two parts, defining the loglevel and checking it.
7025 To define the log levels, the (main) program should pass a string to
7026 <function>yaz_log_mask_str</function> to define which log levels are to be
7027 logged. This string should be a comma-separated list of log level names,
7028 and can contain both hard-coded names and dynamic ones. The log level
7029 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
7030 for each word it meets, unless the word starts with a '-', in which case it
7031 clears the bit. If the string <literal>'none'</literal> is found,
7032 all bits are cleared. Typically this string comes from the command-line,
7033 often identified by <literal>-v</literal>. The
7034 <function>yaz_log_mask_str</function> returns a log level that should be
7035 passed to <function>yaz_log_init_level</function> for it to take effect.
7038 Each module should check what log bits it should be used, by calling
7039 <function>yaz_log_module_level</function> with a suitable name for the
7040 module. The name is cleared from a preceding path and an extension, if any,
7041 so it is quite possible to use <literal>__FILE__</literal> for it. If the
7042 name has been passed to <function>yaz_log_mask_str</function>, the routine
7043 returns a non-zero bitmask, which should then be used in consequent calls
7044 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
7045 yaz_log, in time-critical places, or when the log entry would take time
7049 Yaz uses the following dynamic log levels:
7050 <literal>server, session, request, requestdetail</literal> for the server
7052 <literal>zoom</literal> for the zoom client api.
7053 <literal>ztest</literal> for the simple test server.
7054 <literal>malloc, nmem, odr, eventl</literal> for internal
7055 debugging of yaz itself.
7056 Of course, any program using yaz is welcome to define as many new
7060 By default the log is written to stderr, but this can be changed by a call
7061 to <function>yaz_log_init_file</function> or
7062 <function>yaz_log_init</function>. If the log is directed to a file, the
7063 file size is checked at every write, and if it exceeds the limit given in
7064 <function>yaz_log_init_max_size</function>, the log is rotated. The
7065 rotation keeps one old version (with a <literal>.1</literal> appended to
7066 the name). The size defaults to 1GB. Setting it to zero will disable the
7070 A typical yaz-log looks like this
7071 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
7072 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
7073 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
7074 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
7075 13:24:13-23/11 yaz-ztest(1) [request] Close OK
7078 The log entries start with a time stamp. This can be omitted by setting the
7079 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
7080 can be hoped to produce identical log files, that are easy to diff. The
7081 format of the time stamp can be set with
7082 <function>yaz_log_time_format</function>, which takes a format string just
7083 like <function>strftime</function>.
7086 Next in a log line comes the prefix, often the name of the program. For
7087 yaz-based servers, it can also contain the session number. Then
7088 comes one or more logbits in square brackets, depending on the logging
7089 level set by <function>yaz_log_init_level</function> and the loglevel
7090 passed to <function>yaz_log_init_level</function>. Finally comes the format
7091 string and additional values passed to <function>yaz_log</function>
7094 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
7095 <literal>loglevel</literal>, will log all the log-level affecting
7096 operations. This can come in handy if you need to know what other log
7097 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
7100 The log system is almost independent of the rest of &yaz;, the only
7101 important dependence is of <filename>nmem</filename>, and that only for
7102 using the semaphore definition there.
7105 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
7106 the same time, the log bit names were changed from
7107 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
7108 to avoid collision with <filename>syslog.h</filename>.
7114 YAZ provides a fast utility for working with MARC records.
7115 Early versions of the MARC utility only allowed decoding of ISO2709.
7116 Today the utility may both encode - and decode to a varity of formats.
7119 #include <yaz/marcdisp.h>
7121 /* create handler */
7122 yaz_marc_t yaz_marc_create(void);
7124 void yaz_marc_destroy(yaz_marc_t mt);
7126 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
7127 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
7128 #define YAZ_MARC_LINE 0
7129 #define YAZ_MARC_SIMPLEXML 1
7130 #define YAZ_MARC_OAIMARC 2
7131 #define YAZ_MARC_MARCXML 3
7132 #define YAZ_MARC_ISO2709 4
7133 #define YAZ_MARC_XCHANGE 5
7134 #define YAZ_MARC_CHECK 6
7135 #define YAZ_MARC_TURBOMARC 7
7136 #define YAZ_MARC_JSON 8
7138 /* supply iconv handle for character set conversion .. */
7139 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
7141 /* set debug level, 0=none, 1=more, 2=even more, .. */
7142 void yaz_marc_debug(yaz_marc_t mt, int level);
7144 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7145 On success, result in *result with size *rsize. */
7146 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7147 const char **result, size_t *rsize);
7149 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7150 On success, result in WRBUF */
7151 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7152 int bsize, WRBUF wrbuf);
7157 The synopsis is just a basic subset of all functionality. Refer
7158 to the actual header file <filename>marcdisp.h</filename> for
7163 A MARC conversion handle must be created by using
7164 <function>yaz_marc_create</function> and destroyed
7165 by calling <function>yaz_marc_destroy</function>.
7168 All other function operate on a <literal>yaz_marc_t</literal> handle.
7169 The output is specified by a call to <function>yaz_marc_xml</function>.
7170 The <literal>xmlmode</literal> must be one of
7173 <term>YAZ_MARC_LINE</term>
7176 A simple line-by-line format suitable for display but not
7177 recommend for further (machine) processing.
7182 <term>YAZ_MARC_MARCXML</term>
7185 <ulink url="&url.marcxml;">MARCXML</ulink>.
7190 <term>YAZ_MARC_ISO2709</term>
7193 ISO2709 (sometimes just referred to as "MARC").
7198 <term>YAZ_MARC_XCHANGE</term>
7201 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7206 <term>YAZ_MARC_CHECK</term>
7209 Pseudo format for validation only. Does not generate
7210 any real output except diagnostics.
7215 <term>YAZ_MARC_TURBOMARC</term>
7218 XML format with same semantics as MARCXML but more compact
7219 and geared towards fast processing with XSLT. Refer to
7220 <xref linkend="tools.turbomarc"/> for more information.
7225 <term>YAZ_MARC_JSON</term>
7228 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7235 The actual conversion functions are
7236 <function>yaz_marc_decode_buf</function> and
7237 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7238 a MARC record. The former function operates on simple buffers, the
7239 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7242 <example id="example.marc.display">
7243 <title>Display of MARC record</title>
7245 The following program snippet illustrates how the MARC API may
7246 be used to convert a MARC record to the line-by-line format:
7247 <programlisting><![CDATA[
7248 void print_marc(const char *marc_buf, int marc_buf_size)
7250 char *result; /* for result buf */
7251 size_t result_len; /* for size of result */
7252 yaz_marc_t mt = yaz_marc_create();
7253 yaz_marc_xml(mt, YAZ_MARC_LINE);
7254 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7255 &result, &result_len);
7256 fwrite(result, result_len, 1, stdout);
7257 yaz_marc_destroy(mt); /* note that result is now freed... */
7263 <sect2 id="tools.turbomarc">
7264 <title>TurboMARC</title>
7266 TurboMARC is yet another XML encoding of a MARC record. The format
7267 was designed for fast processing with XSLT.
7271 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7272 representation. This conversion mostly check the tag of a MARC field
7273 to determine the basic rules in the conversion. This check is
7274 costly when that is tag is encoded as an attribute in MARCXML.
7275 By having the tag value as the element instead, makes processing
7276 many times faster (at least for Libxslt).
7279 TurboMARC is encoded as follows:
7283 Record elements is part of namespace
7284 "<literal>http://www.indexdata.com/turbomarc</literal>".
7289 A record is enclosed in element <literal>r</literal>.
7294 A collection of records is enclosed in element
7295 <literal>collection</literal>.
7300 The leader is encoded as element <literal>l</literal> with the
7301 leader content as its (text) value.
7306 A control field is encoded as element <literal>c</literal> concatenated
7307 with the tag value of the control field if the tag value
7308 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7309 If the tag value do not match the regular expression
7310 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7311 as element <literal>c</literal> and attribute <literal>code</literal>
7312 will hold the tag value.
7313 This rule ensure that in the rare cases where a tag value might
7314 result in a non-wellformed XML YAZ encode it as a coded attribute
7318 The control field content is the the text value of this element.
7319 Indicators are encoded as attribute names
7320 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7321 corresponding values for each indicator.
7326 A data field is encoded as element <literal>d</literal> concatenated
7327 with the tag value of the data field or using the attribute
7328 <literal>code</literal> as described in the rules for control fields.
7329 The children of the data field element is subfield elements.
7330 Each subfield element is encoded as <literal>s</literal>
7331 concatenated with the sub field code.
7332 The text of the subfield element is the contents of the subfield.
7333 Indicators are encoded as attributes for the data field element similar
7334 to the encoding for control fields.
7341 <sect1 id="tools.retrieval">
7342 <title>Retrieval Facility</title>
7344 YAZ version 2.1.20 or later includes a Retrieval facility tool
7345 which allows a SRU/Z39.50 to describe itself and perform record
7346 conversions. The idea is the following:
7350 An SRU/Z39.50 client sends a retrieval request which includes
7351 a combination of the following parameters: syntax (format),
7352 schema (or element set name).
7357 The retrieval facility is invoked with parameters in a
7358 server/proxy. The retrieval facility matches the parameters a set of
7359 "supported" retrieval types.
7360 If there is no match, the retrieval signals an error
7361 (syntax and / or schema not supported).
7366 For a successful match, the backend is invoked with the same
7367 or altered retrieval parameters (syntax, schema). If
7368 a record is received from the backend, it is converted to the
7369 frontend name / syntax.
7374 The resulting record is sent back the client and tagged with
7375 the frontend syntax / schema.
7381 The Retrieval facility is driven by an XML configuration. The
7382 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7383 should be easy to generate both of them from the XML configuration.
7384 (unfortunately the two versions
7385 of ZeeRex differ substantially in this regard).
7387 <sect2 id="tools.retrieval.format">
7388 <title>Retrieval XML format</title>
7390 All elements should be covered by namespace
7391 <literal>http://indexdata.com/yaz</literal> .
7392 The root element node must be <literal>retrievalinfo</literal>.
7395 The <literal>retrievalinfo</literal> must include one or
7396 more <literal>retrieval</literal> elements. Each
7397 <literal>retrieval</literal> defines specific combination of
7398 syntax, name and identifier supported by this retrieval service.
7401 The <literal>retrieval</literal> element may include any of the
7402 following attributes:
7404 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7407 Defines the record syntax. Possible values is any
7408 of the names defined in YAZ' OID database or a raw
7413 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7416 Defines the name of the retrieval format. This can be
7417 any string. For SRU, the value, is equivalent to schema (short-hand);
7418 for Z39.50 it's equivalent to simple element set name.
7419 For YAZ 3.0.24 and later this name may be specified as a glob
7420 expression with operators
7421 <literal>*</literal> and <literal>?</literal>.
7425 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7428 Defines the URI schema name of the retrieval format. This can be
7429 any string. For SRU, the value, is equivalent to URI schema.
7430 For Z39.50, there is no equivalent.
7437 The <literal>retrieval</literal> may include one
7438 <literal>backend</literal> element. If a <literal>backend</literal>
7439 element is given, it specifies how the records are retrieved by
7440 some backend and how the records are converted from the backend to
7444 The attributes, <literal>name</literal> and <literal>syntax</literal>
7445 may be specified for the <literal>backend</literal> element. These
7446 semantics of these attributes is equivalent to those for the
7447 <literal>retrieval</literal>. However, these values are passed to
7451 The <literal>backend</literal> element may includes one or more
7452 conversion instructions (as children elements). The supported
7455 <varlistentry><term><literal>marc</literal></term>
7458 The <literal>marc</literal> element specifies a conversion
7459 to - and from ISO2709 encoded MARC and
7460 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7461 The following attributes may be specified:
7464 <term><literal>inputformat</literal> (REQUIRED)</term>
7467 Format of input. Supported values are
7468 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7469 (MARCXML/MarcXchange) and <literal>json</literal>
7470 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7475 <term><literal>outputformat</literal> (REQUIRED)</term>
7478 Format of output. Supported values are
7479 <literal>line</literal> (MARC line format);
7480 <literal>marcxml</literal> (for MARCXML),
7481 <literal>marc</literal> (ISO2709),
7482 <literal>marcxhcange</literal> (for MarcXchange),
7483 or <literal>json</literal>
7484 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7489 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7492 Encoding of input. For XML input formats, this need not
7493 be given, but for ISO2709 based inputformats, this should
7494 be set to the encoding used. For MARC21 records, a common
7495 inputcharset value would be <literal>marc-8</literal>.
7500 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7503 Encoding of output. If outputformat is XML based, it is
7504 strongly recommened to use <literal>utf-8</literal>.
7513 <term><literal>select</literal></term>
7516 The <literal>select</literal> selects one or more text nodes
7517 and decodes them as XML.
7518 The following attributes may be specified:
7520 <varlistentry><term><literal>path</literal> (REQUIRED)</term>
7523 X-Path expression for selecting text nodes.
7530 This conversion is available in YAZ 5.8.0 and later.
7535 <term><literal>solrmarc</literal></term>
7538 The <literal>solrmarc</literal> decodes solrmarc records.
7539 It assumes that the input is pure solrmarc text (no escaping)
7540 and will convert all sequences of the form #XX; to a single
7541 character of the hexadecimal value as given by XX. The output,
7542 presumably, is a valid ISO2709 buffer.
7545 This conversion is available in YAZ 5.0.21 and later.
7550 <term><literal>xslt</literal></term>
7553 The <literal>xslt</literal> element specifies a conversion
7554 via &acro.xslt;. The following attributes may be specified:
7556 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7570 <sect2 id="tools.retrieval.examples">
7571 <title>Retrieval Facility Examples</title>
7572 <example id="tools.retrieval.marc21">
7573 <title>MARC21 backend</title>
7575 A typical way to use the retrieval facility is to enable XML
7576 for servers that only supports ISO2709 encoded MARC21 records.
7578 <programlisting><![CDATA[
7580 <retrieval syntax="usmarc" name="F"/>
7581 <retrieval syntax="usmarc" name="B"/>
7582 <retrieval syntax="xml" name="marcxml"
7583 identifier="info:srw/schema/1/marcxml-v1.1">
7584 <backend syntax="usmarc" name="F">
7585 <marc inputformat="marc" outputformat="marcxml"
7586 inputcharset="marc-8"/>
7589 <retrieval syntax="xml" name="dc">
7590 <backend syntax="usmarc" name="F">
7591 <marc inputformat="marc" outputformat="marcxml"
7592 inputcharset="marc-8"/>
7593 <xslt stylesheet="MARC21slim2DC.xsl"/>
7600 This means that our frontend supports:
7604 MARC21 F(ull) records.
7609 MARC21 B(rief) records.
7619 Dublin core records.
7625 <example id="tools.retrieval.marcxml">
7626 <title>MARCXML backend</title>
7628 SRW/SRU and Solr backends returns records in XML.
7629 If they return MARCXML or MarcXchange, the retrieval module
7630 can convert those into ISO2709 formats, most commonly USMARC
7632 In this example, the backend returns MARCXML for schema="marcxml".
7634 <programlisting><![CDATA[
7636 <retrieval syntax="usmarc">
7637 <backend syntax="xml" name="marcxml">
7638 <marc inputformat="xml" outputformat="marc"
7639 outputcharset="marc-8"/>
7642 <retrieval syntax="xml" name="marcxml"
7643 identifier="info:srw/schema/1/marcxml-v1.1"/>
7644 <retrieval syntax="xml" name="dc">
7645 <backend syntax="xml" name="marcxml">
7646 <xslt stylesheet="MARC21slim2DC.xsl"/>
7653 This means that our frontend supports:
7657 MARC21 records (any element set name) in MARC-8 encoding.
7662 MARCXML records for element-set=marcxml
7667 Dublin core records for element-set=dc.
7674 <sect2 id="tools.retrieval.api">
7677 It should be easy to use the retrieval systems from applications. Refer
7679 <filename>yaz/retrieval.h</filename> and
7680 <filename>yaz/record_conv.h</filename>.
7684 <sect1 id="sorting">
7685 <title>Sorting</title>
7687 This chapter describes sorting and how it is supported in YAZ.
7688 Sorting applies to a result-set.
7690 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7691 Z39.50 sorting facility
7693 takes one or more input result-sets
7694 and one result-set as output. The most simple case is that
7695 the input-set is the same as the output-set.
7698 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7699 following a search (two phases).
7702 In SRU/Solr, however, the model is different. Here, sorting is specified
7703 during the the search operation. Note, however, that SRU might
7704 perform sort as separate search, by referring to an existing result-set
7705 in the query (result-set reference).
7708 <title>Using the Z39.50 sort service</title>
7710 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7711 case the sort sequence or sort critiera is using a string notation.
7712 This notation is a one-line notation suitable for being manually
7713 entered or generated and allows for easy logging (one liner).
7714 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7715 function. For yaz-client the sort is performed and specified using
7716 the sort and sort+ commands. For description of the sort criteria notation
7717 refer to the <link linkend="sortspec">sort command</link> in the
7721 The ZOOM API might choose one of several sort strategies for
7722 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7726 <title>Type-7 sort</title>
7728 Type-7 sort is an extension to the Bib-1 based RPN query where the
7729 sort specification is embedded as an Attribute-Plus-Term.
7732 The objectives for introducing Type-7 sorting is that it allows
7733 a client to perform sorting even if it does not implement/support
7734 Z39.50 sort. Virtually all Z39.50 client software supports
7735 RPN queries. It also may improve performance because the sort
7736 critieria is specified along with the search query.
7739 The sort is triggered by the presence of type 7 and the value of type 7
7741 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7744 The value for type 7 is 1 for ascending and 2 for descending.
7746 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7749 only the generic part is handled. If generic sortKey is of type
7750 sortField, then attribute type 1 is present and the value is
7751 sortField (InternationalString). If generic sortKey is of type
7752 sortAttributes, then the attributes in list is used . generic sortKey
7753 of type elementSpec is not supported.
7756 The term in the sorting Attribute-Plus-Term combo should hold
7757 an integer. The value is 0 for primary sorting criteria, 1 for second
7763 <title>Facets</title>
7765 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7768 Like Type-1/RPN, YAZ supports a string notation for specifying
7769 facets. For the API this is performed by
7770 <function>yaz_pqf_parse_facet_list</function>.
7773 For ZOOM C the facets are given by option "facets"
7774 For yaz-client it is used for the facets command.
7777 The grammar of this specification is as follows:
7779 facet-spec ::= facet-list
7781 facet-list ::= facet-list ',' attr-spec | attr-spec
7783 attr-spec ::= attr-spec '@attr' string | '@attr' string
7786 The notation is inspired by PQF. The string following '@attr'
7787 may not include blanks and is of the form
7788 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7789 where <replaceable>type</replaceable> is an integer and
7790 <replaceable>value</replaceable> is a string or an integer.
7793 The Facets specification is not Bib-1. The following types apply:
7795 <table id="facet.attributes">
7796 <title>Facet attributes</title>
7798 <colspec colwidth="2*" colname="type"></colspec>
7799 <colspec colwidth="9*" colname="description"></colspec>
7803 <entry>Description</entry>
7810 Field-name. This is often a string, eg "Author", "Year", etc.
7816 Sort order. Value should be an integer.
7817 Value 0: count descending (frequency). Value 1: alpha ascending.
7823 Number of terms requested.
7838 <title>The ODR Module</title>
7839 <sect1 id="odr.introduction">
7840 <title>Introduction</title>
7842 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7843 to isolate &odr; from the rest of the package - specifically from the
7844 transport interface. &odr; may be used in any context where basic
7845 ASN.1/BER representations are used.
7848 If you are only interested in writing a Z39.50 implementation based on
7849 the PDUs that are already provided with &yaz;, you only need to concern
7850 yourself with the section on managing ODR streams
7851 (<xref linkend="odr.use"/>). Only if you need to
7852 implement ASN.1 beyond that which has been provided, should you
7853 worry about the second half of the documentation
7854 (<xref linkend="odr.programming"/>).
7855 If you use one of the higher-level interfaces, you can skip this
7859 This is important, so we'll repeat it for emphasis: <emphasis>You do
7860 not need to read <xref linkend="odr.programming"/>
7861 to implement Z39.50 with &yaz;.</emphasis>
7864 If you need a part of the protocol that isn't already in &yaz;, you
7865 should contact the authors before going to work on it yourself: We
7866 might already be working on it. Conversely, if you implement a useful
7867 part of the protocol before us, we'd be happy to include it in a
7871 <sect1 id="odr.use">
7872 <title>Using ODR</title>
7873 <sect2 id="odr.streams">
7874 <title>ODR Streams</title>
7876 Conceptually, the ODR stream is the source of encoded data in the
7877 decoding mode; when encoding, it is the receptacle for the encoded
7878 data. Before you can use an ODR stream it must be allocated. This is
7879 done with the function
7882 ODR odr_createmem(int direction);
7885 The <function>odr_createmem()</function> function takes as argument one
7886 of three manifest constants: <literal>ODR_ENCODE</literal>,
7887 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7888 An &odr; stream can be in only one mode - it is not possible to change
7889 its mode once it's selected. Typically, your program will allocate
7890 at least two ODR streams - one for decoding, and one for encoding.
7893 When you're done with the stream, you can use
7896 void odr_destroy(ODR o);
7899 to release the resources allocated for the stream.
7902 <sect2 id="odr.memory.management">
7903 <title id="memory">Memory Management</title>
7905 Two forms of memory management take place in the &odr; system. The first
7906 one, which has to do with allocating little bits of memory (sometimes
7907 quite large bits of memory, actually) when a protocol package is
7908 decoded, and turned into a complex of interlinked structures. This
7909 section deals with this system, and how you can use it for your own
7910 purposes. The next section deals with the memory management which is
7911 required when encoding data - to make sure that a large enough buffer is
7912 available to hold the fully encoded PDU.
7915 The &odr; module has its own memory management system, which is
7916 used whenever memory is required. Specifically, it is used to allocate
7917 space for data when decoding incoming PDUs. You can use the memory
7918 system for your own purposes, by using the function
7921 void *odr_malloc(ODR o, size_t size);
7924 You can't use the normal <function>free(2)</function> routine to free
7925 memory allocated by this function, and &odr; doesn't provide a parallel
7926 function. Instead, you can call
7929 void odr_reset(ODR o);
7932 when you are done with the
7933 memory: Everything allocated since the last call to
7934 <function>odr_reset()</function> is released.
7935 The <function>odr_reset()</function> call is also required to clear
7936 up an error condition on a stream.
7942 size_t odr_total(ODR o);
7945 returns the number of bytes allocated on the stream since the last call to
7946 <function>odr_reset()</function>.
7949 The memory subsystem of &odr; is fairly efficient at allocating and
7950 releasing little bits of memory. Rather than managing the individual,
7951 small bits of space, the system maintains a free-list of larger chunks
7952 of memory, which are handed out in small bits. This scheme is
7953 generally known as a <emphasis>nibble memory</emphasis> system.
7954 It is very useful for maintaining short-lived constructions such
7958 If you want to retain a bit of memory beyond the next call to
7959 <function>odr_reset()</function>, you can use the function
7962 ODR_MEM odr_extract_mem(ODR o);
7965 This function will give you control of the memory recently allocated
7966 on the ODR stream. The memory will live (past calls to
7967 <function>odr_reset()</function>), until you call the function
7970 void odr_release_mem(ODR_MEM p);
7973 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
7974 referencing the memory block for you until you want to release it.
7977 You can use <function>odr_extract_mem()</function> repeatedly between
7978 allocating data, to retain individual control of separate chunks of data.
7981 <sect2 id="odr.encoding.and.decoding">
7982 <title>Encoding and Decoding Data</title>
7984 When encoding data, the ODR stream will write the encoded octet string
7985 in an internal buffer. To retrieve the data, use the function
7988 char *odr_getbuf(ODR o, int *len, int *size);
7991 The integer pointed to by len is set to the length of the encoded
7992 data, and a pointer to that data is returned. <literal>*size</literal>
7993 is set to the size of the buffer (unless <literal>size</literal> is null,
7994 signaling that you are not interested in the size). The next call to
7995 a primitive function using the same &odr; stream will overwrite the
7996 data, unless a different buffer has been supplied using the call
7999 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8002 which sets the encoding (or decoding) buffer used by
8003 <literal>o</literal> to <literal>buf</literal>, using the length
8004 <literal>len</literal>.
8005 Before a call to an encoding function, you can use
8006 <function>odr_setbuf()</function> to provide the stream with an encoding
8007 buffer of sufficient size (length). The <literal>can_grow</literal>
8008 parameter tells the encoding &odr; stream whether it is allowed to use
8009 <function>realloc(2)</function> to increase the size of the buffer when
8010 necessary. The default condition of a new encoding stream is equivalent
8011 to the results of calling
8014 odr_setbuf(stream, 0, 0, 1);
8017 In this case, the stream will allocate and reallocate memory as
8018 necessary. The stream reallocates memory by repeatedly doubling the
8019 size of the buffer - the result is that the buffer will typically
8020 reach its maximum, working size with only a small number of reallocation
8021 operations. The memory is freed by the stream when the latter is destroyed,
8022 unless it was assigned by the user with the <literal>can_grow</literal>
8023 parameter set to zero (in this case, you are expected to retain
8024 control of the memory yourself).
8027 To assume full control of an encoded buffer, you must first call
8028 <function>odr_getbuf()</function> to fetch the buffer and its length.
8029 Next, you should call <function>odr_setbuf()</function> to provide a
8030 different buffer (or a null pointer) to the stream. In the simplest
8031 case, you will reuse the same buffer over and over again, and you
8032 will just need to call <function>odr_getbuf()</function> after each
8033 encoding operation to get the length and address of the buffer.
8034 Note that the stream may reallocate the buffer during an encoding
8035 operation, so it is necessary to retrieve the correct address after
8036 each encoding operation.
8039 It is important to realize that the ODR stream will not release this
8040 memory when you call <function>odr_reset()</function>: It will
8041 merely update its internal pointers to prepare for the encoding of a
8043 When the stream is released by the <function>odr_destroy()</function>
8044 function, the memory given to it by <function>odr_setbuf</function> will
8045 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
8046 parameter to <function>odr_setbuf()</function> was nonzero. The
8047 <literal>can_grow</literal> parameter, in other words, is a way of
8048 signaling who is to own the buffer, you or the ODR stream. If you never call
8049 <function>odr_setbuf()</function> on your encoding stream, which is
8050 typically the case, the buffer allocated by the stream will belong to
8051 the stream by default.
8054 When you wish to decode data, you should first call
8055 <function>odr_setbuf()</function>, to tell the decoding stream
8056 where to find the encoded data, and how long the buffer is
8057 (the <literal>can_grow</literal> parameter is ignored by a decoding
8058 stream). After this, you can call the function corresponding to the
8059 data you wish to decode (eg, <function>odr_integer()</function> odr
8060 <function>z_APDU()</function>).
8062 <example id="example.odr.encoding.and.decoding.functions">
8063 <title>Encoding and decoding functions</title>
8065 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8067 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
8071 If the data is absent (or doesn't match the tag corresponding to
8072 the type), the return value will be either 0 or 1 depending on the
8073 <literal>optional</literal> flag. If <literal>optional</literal>
8074 is 0 and the data is absent, an error flag will be raised in the
8075 stream, and you'll need to call <function>odr_reset()</function> before
8076 you can use the stream again. If <literal>optional</literal> is
8077 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
8078 <literal>p</literal> will be set to the null value, and the function
8080 The <literal>name</literal> argument is used to pretty-print the
8081 tag in question. It may be set to <literal>NULL</literal> if
8082 pretty-printing is not desired.
8085 If the data value is found where it's expected, the pointer
8086 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
8087 will be set to point to the decoded type.
8088 The space for the type will be allocated and owned by the &odr;
8089 stream, and it will live until you call
8090 <function>odr_reset()</function> on the stream. You cannot use
8091 <function>free(2)</function> to release the memory.
8092 You can decode several data elements (by repeated calls to
8093 <function>odr_setbuf()</function> and your decoding function), and
8094 new memory will be allocated each time. When you do call
8095 <function>odr_reset()</function>, everything decoded since the
8096 last call to <function>odr_reset()</function> will be released.
8098 <example id="example.odr.encoding.of.integer">
8099 <title>Encoding and decoding of an integer</title>
8101 The use of the double indirection can be a little confusing at first
8102 (its purpose will become clear later on, hopefully),
8103 so an example is in order. We'll encode an integer value, and
8104 immediately decode it again using a different stream. A useless, but
8105 informative operation.
8107 <programlisting><![CDATA[
8108 void do_nothing_useful(Odr_int value)
8111 Odr_int *valp, *resvalp;
8115 /* allocate streams */
8116 if (!(encode = odr_createmem(ODR_ENCODE)))
8118 if (!(decode = odr_createmem(ODR_DECODE)))
8122 if (odr_integer(encode, &valp, 0, 0) == 0)
8124 printf("encoding went bad\n");
8127 bufferp = odr_getbuf(encode, &len, 0);
8128 printf("length of encoded data is %d\n", len);
8130 /* now let's decode the thing again */
8131 odr_setbuf(decode, bufferp, len, 0);
8132 if (odr_integer(decode, &resvalp, 0, 0) == 0)
8134 printf("decoding went bad\n");
8137 /* ODR_INT_PRINTF format for printf (such as %d) */
8138 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
8141 odr_destroy(encode);
8142 odr_destroy(decode);
8147 This looks like a lot of work, offhand. In practice, the &odr; streams
8148 will typically be allocated once, in the beginning of your program
8149 (or at the beginning of a new network session), and the encoding
8150 and decoding will only take place in a few, isolated places in your
8151 program, so the overhead is quite manageable.
8155 <sect2 id="odr.printing">
8156 <title>Printing</title>
8158 When an ODR stream is created of type <literal>ODR_PRINT</literal>
8159 the ODR module will print the contents of a PDU in a readable format.
8160 By default output is written to the <literal>stderr</literal> stream.
8161 This behavior can be changed, however, by calling the function
8163 odr_setprint(ODR o, FILE *file);
8165 before encoders or decoders are being invoked.
8166 It is also possible to direct the output to a buffer (of indeed
8167 another file), by using the more generic mechanism:
8169 void odr_set_stream(ODR o, void *handle,
8170 void (*stream_write)(ODR o, void *handle, int type,
8171 const char *buf, int len),
8172 void (*stream_close)(void *handle));
8174 Here the user provides an opaque handle and two handlers,
8175 <replaceable>stream_write</replaceable> for writing,
8176 and <replaceable>stream_close</replaceable> which is supposed
8177 to close/free resources associated with handle.
8178 The <replaceable>stream_close</replaceable> handler is optional and
8179 if NULL for the function is provided, it will not be invoked.
8180 The <replaceable>stream_write</replaceable> takes the ODR handle
8181 as parameter, the user defined handle, a type
8182 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8183 which indicates the type of contents is being written.
8186 Another utility useful for diagnostics (error handling) or as
8187 part of the printing facilities is:
8189 const char **odr_get_element_path(ODR o);
8191 which returns a list of current elements that ODR deals with at the
8192 moment. For the returned array, say <literal>ar</literal>,
8193 <literal>ar[0]</literal> is the top level element,
8194 <literal>ar[n]</literal> is the last. The last element has the
8195 property that <literal>ar[n+1] == NULL</literal>.
8197 <example id="example.odr.element.path.record">
8198 <title>Element Path for record</title>
8200 For a database record part of a PresentResponse the
8201 array returned by <function>odr_get_element</function>
8202 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8203 unnamed constructions.
8207 <sect2 id="odr.diagnostics">
8208 <title>Diagnostics</title>
8210 The encoding/decoding functions all return 0 when an error occurs.
8211 Until you call <function>odr_reset()</function>, you cannot use the
8212 stream again, and any function called will immediately return 0.
8215 To provide information to the programmer or administrator, the function
8218 void odr_perror(ODR o, char *message);
8221 is provided, which prints the <literal>message</literal> argument to
8222 <literal>stderr</literal> along with an error message from the stream.
8225 You can also use the function
8228 int odr_geterror(ODR o);
8231 to get the current error number from the screen. The number will be
8232 one of these constants:
8234 <table frame="top" id="odr.error.codes">
8235 <title>ODR Error codes</title>
8240 <entry>Description</entry>
8245 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8248 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8249 The standard diagnostic variable <literal>errno</literal> should be
8250 examined to determine the actual error.</entry>
8253 <entry>OSPACE</entry><entry>No more space for encoding.
8254 This will only occur when the user has explicitly provided a
8255 buffer for an encoding stream without allowing the system to
8256 allocate more space.</entry>
8259 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8260 required data element was missing during encoding or decoding.</entry>
8263 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8264 found during decoding.</entry>
8267 <entry>OOTHER</entry><entry>Other error. This is typically an
8268 indication of misuse of the &odr; system by the programmer, and also
8269 that the diagnostic system isn't as good as it should be, yet.</entry>
8275 The character string array
8281 can be indexed by the error code to obtain a human-readable
8282 representation of the problem.
8285 <sect2 id="odr.summary.and.synopsis">
8286 <title>Summary and Synopsis</title>
8288 #include <yaz/odr.h>
8290 ODR odr_createmem(int direction);
8292 void odr_destroy(ODR o);
8294 void odr_reset(ODR o);
8296 char *odr_getbuf(ODR o, int *len, int *size);
8298 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8300 void *odr_malloc(ODR o, int size);
8302 NMEM odr_extract_mem(ODR o);
8304 int odr_geterror(ODR o);
8306 void odr_perror(ODR o, const char *message);
8308 extern char *odr_errlist[];
8312 <sect1 id="odr.programming">
8313 <title>Programming with ODR</title>
8315 The API of &odr; is designed to reflect the structure of ASN.1, rather
8316 than BER itself. Future releases may be able to represent data in
8317 other external forms.
8321 There is an ASN.1 tutorial available at
8322 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8323 This site also has standards for ASN.1 (X.680) and BER (X.690)
8324 <ulink url="&url.asn.1.standards;">online</ulink>.
8328 The ODR interface is based loosely on that of the Sun Microsystems
8330 Specifically, each function which corresponds to an ASN.1 primitive
8331 type has a dual function. Depending on the settings of the ODR
8332 stream which is supplied as a parameter, the function may be used
8333 either to encode or decode data. The functions that can be built
8334 using these primitive functions, to represent more complex data types,
8335 share this quality. The result is that you only have to enter the
8336 definition for a type once - and you have the functionality of encoding,
8337 decoding (and pretty-printing) all in one unit.
8338 The resulting C source code is quite compact, and is a pretty
8339 straightforward representation of the source ASN.1 specification.
8342 In many cases, the model of the XDR functions works quite well in this
8344 In others, it is less elegant. Most of the hassle comes from the optional
8345 SEQUENCE members which don't exist in XDR.
8347 <sect2 id="odr.primitive.asn1.types">
8348 <title>The Primitive ASN.1 Types</title>
8350 ASN.1 defines a number of primitive types (many of which correspond
8351 roughly to primitive types in structured programming languages, such as C).
8353 <sect3 id="odr.integer">
8354 <title>INTEGER</title>
8356 The &odr; function for encoding or decoding (or printing) the ASN.1
8357 INTEGER type looks like this:
8360 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8363 The <literal>Odr_int</literal> is just a simple integer.
8366 This form is typical of the primitive &odr; functions. They are named
8367 after the type of data that they encode or decode. They take an &odr;
8368 stream, an indirect reference to the type in question, and an
8369 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8370 of ASN.1) as parameters. They all return an integer value of either one
8372 When you use the primitive functions to construct encoders for complex
8373 types of your own, you should follow this model as well. This
8374 ensures that your new types can be reused as elements in yet more
8378 The <literal>o</literal> parameter should obviously refer to a properly
8379 initialized &odr; stream of the right type (encoding/decoding/printing)
8380 for the operation that you wish to perform.
8383 When encoding or printing, the function first looks at
8384 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8385 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8386 the data element is absent. If the <literal>optional</literal> parameter
8387 is nonzero, the function will return one (signifying success) without
8388 any further processing. If the <literal>optional</literal> is zero, an
8389 internal error flag is set in the &odr; stream, and the function will
8390 return 0. No further operations can be carried out on the stream without
8391 a call to the function <function>odr_reset()</function>.
8394 If <literal>*p</literal> is not a null pointer, it is expected to
8395 point to an instance of the data type. The data will be subjected to
8396 the encoding rules, and the result will be placed in the buffer held
8397 by the &odr; stream.
8400 The other ASN.1 primitives have similar functions that operate in
8404 <sect3 id="odr.boolean">
8405 <title>BOOLEAN</title>
8407 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8410 <sect3 id="odr.real">
8416 <sect3 id="odr.null">
8419 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8422 In this case, the value of **p is not important. If <literal>*p</literal>
8423 is different from the null pointer, the null value is present, otherwise
8427 <sect3 id="odr.octet.string">
8428 <title>OCTET STRING</title>
8430 typedef struct odr_oct
8436 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8440 The <literal>buf</literal> field should point to the character array
8441 that holds the octetstring. The <literal>len</literal> field holds the
8443 The character array need not be null terminated.
8446 To make things a little easier, an alternative is given for string
8447 types that are not expected to contain embedded NULL characters (eg.
8451 int odr_cstring(ODR o, char **p, int optional, const char *name);
8454 Which encoded or decodes between OCTETSTRING representations and
8455 null-terminates C strings.
8458 Functions are provided for the derived string types, eg:
8461 int odr_visiblestring(ODR o, char **p, int optional,
8465 <sect3 id="odr.bit.string">
8466 <title>BIT STRING</title>
8468 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8472 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8473 holding relatively brief bit strings, eg. for options fields, etc.
8474 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8475 gives the maximum possible number of bits.
8478 A set of macros are provided for manipulating the
8479 <literal>Odr_bitmask</literal> type:
8482 void ODR_MASK_ZERO(Odr_bitmask *b);
8484 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8486 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8488 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8491 The functions are modeled after the manipulation functions that
8492 accompany the <literal>fd_set</literal> type used by the
8493 <function>select(2)</function> call.
8494 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8495 new bitmask, to initialize the bits to zero.
8498 <sect3 id="odr.object.identifier">
8499 <title>OBJECT IDENTIFIER</title>
8501 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8504 The C OID representation is simply an array of integers, terminated by
8505 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8506 the <literal>short</literal> type).
8507 We suggest that you use the OID database module (see
8508 <xref linkend="tools.oid.database"/>) to handle object identifiers
8509 in your application.
8513 <sect2 id="odr.tagging.primitive.types">
8514 <title>Tagging Primitive Types</title>
8516 The simplest way of tagging a type is to use the
8517 <function>odr_implicit_tag()</function> or
8518 <function>odr_explicit_tag()</function> macros:
8521 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8522 int optional, const char *name);
8524 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8525 int optional, const char *name);
8528 To create a type derived from the integer type by implicit tagging, you
8532 MyInt ::= [210] IMPLICIT INTEGER
8535 In the &odr; system, this would be written like:
8538 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8540 return odr_implicit_tag(o, odr_integer, p,
8541 ODR_CONTEXT, 210, optional, name);
8545 The function <function>myInt()</function> can then be used like any of
8546 the primitive functions provided by &odr;. Note that the behavior of
8547 <function>odr_explicit_tag()</function>
8548 and <function>odr_implicit_tag()</function> macros
8549 act exactly the same as the functions they are applied to - they
8550 respond to error conditions, etc, in the same manner - they
8551 simply have three extra parameters. The class parameter may
8552 take one of the values: <literal>ODR_CONTEXT</literal>,
8553 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8554 <literal>/ODR_APPLICATION</literal>.
8557 <sect2 id="odr.constructed.types">
8558 <title>Constructed Types</title>
8560 Constructed types are created by combining primitive types. The
8561 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8562 (although adding the rest of the container types should be simple
8563 enough, if the need arises).
8566 For implementing SEQUENCEs, the functions
8569 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8570 int odr_sequence_end(ODR o);
8576 The <function>odr_sequence_begin()</function> function should be
8577 called in the beginning of a function that implements a SEQUENCE type.
8578 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8579 you're implementing), and the <literal>size</literal> of the type
8580 (typically a C structure). On encoding, it returns 1 if
8581 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8582 parameter is ignored. On decoding, it returns 1 if the type is found in
8583 the data stream. <literal>size</literal> bytes of memory are allocated,
8584 and <literal>*p</literal> is set to point to this space.
8585 <function>odr_sequence_end()</function> is called at the end of the
8586 complex function. Assume that a type is defined like this:
8589 MySequence ::= SEQUENCE {
8591 boolval BOOLEAN OPTIONAL
8595 The corresponding &odr; encoder/decoder function and the associated data
8596 structures could be written like this:
8599 typedef struct MySequence
8605 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8607 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8608 return optional && odr_ok(o);
8610 odr_integer(o, &(*p)->intval, 0, "intval") &&
8611 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8612 odr_sequence_end(o);
8616 Note the 1 in the call to <function>odr_bool()</function>, to mark
8617 that the sequence member is optional.
8618 If either of the member types had been tagged, the macros
8619 <function>odr_implicit_tag()</function> or
8620 <function>odr_explicit_tag()</function>
8621 could have been used.
8622 The new function can be used exactly like the standard functions provided
8623 with &odr;. It will encode, decode or pretty-print a data value of the
8624 <literal>MySequence</literal> type. We like to name types with an
8625 initial capital, as done in ASN.1 definitions, and to name the
8626 corresponding function with the first character of the name in lower case.
8627 You could, of course, name your structures, types, and functions any way
8628 you please - as long as you're consistent, and your code is easily readable.
8629 <literal>odr_ok</literal> is just that - a predicate that returns the
8630 state of the stream. It is used to ensure that the behavior of the new
8631 type is compatible with the interface of the primitive types.
8634 <sect2 id="odr.tagging.constructed.types">
8635 <title>Tagging Constructed Types</title>
8638 See <xref linkend="odr.tagging.primitive.types"/> for information
8639 on how to tag the primitive types, as well as types that are
8643 <sect3 id="odr.implicit.tagging">
8644 <title>Implicit Tagging</title>
8646 Assume the type above had been defined as
8649 MySequence ::= [10] IMPLICIT SEQUENCE {
8651 boolval BOOLEAN OPTIONAL
8655 You would implement this in &odr; by calling the function
8658 int odr_implicit_settag(ODR o, int class, int tag);
8661 which overrides the tag of the type immediately following it. The
8662 macro <function>odr_implicit_tag()</function> works by calling
8663 <function>odr_implicit_settag()</function> immediately
8664 before calling the function pointer argument.
8665 Your type function could look like this:
8668 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8670 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8671 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8672 return optional && odr_ok(o);
8674 odr_integer(o, &(*p)->intval, 0, "intval") &&
8675 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8676 odr_sequence_end(o);
8680 The definition of the structure <literal>MySequence</literal> would be
8684 <sect3 id="odr.explicit.tagging">
8685 <title>Explicit Tagging</title>
8687 Explicit tagging of constructed types is a little more complicated,
8688 since you are in effect adding a level of construction to the data.
8691 Assume the definition:
8694 MySequence ::= [10] IMPLICIT SEQUENCE {
8696 boolval BOOLEAN OPTIONAL
8700 Since the new type has an extra level of construction, two new functions
8701 are needed to encapsulate the base type:
8704 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8707 int odr_constructed_end(ODR o);
8710 Assume that the IMPLICIT in the type definition above were replaced
8711 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8712 would be equivalent). The structure definition would look the same,
8713 but the function would look like this:
8716 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8718 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8719 return optional && odr_ok(o);
8720 if (o->direction == ODR_DECODE)
8721 *p = odr_malloc(o, sizeof(**p));
8722 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8724 *p = 0; /* this is almost certainly a protocol error */
8728 odr_integer(o, &(*p)->intval, 0, "intval") &&
8729 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8730 odr_sequence_end(o) &&
8731 odr_constructed_end(o);
8735 Notice that the interface here gets kind of nasty. The reason is
8736 simple: Explicitly tagged, constructed types are fairly rare in
8737 the protocols that we care about, so the
8738 esthetic annoyance (not to mention the dangers of a cluttered
8739 interface) is less than the time that would be required to develop a
8740 better interface. Nevertheless, it is far from satisfying, and it's a
8741 point that will be worked on in the future. One option for you would
8742 be to simply apply the <function>odr_explicit_tag()</function> macro to
8743 the first function, and not
8744 have to worry about <function>odr_constructed_*</function> yourself.
8745 Incidentally, as you might have guessed, the
8746 <function>odr_sequence_</function> functions are themselves
8747 implemented using the <function>/odr_constructed_</function> functions.
8751 <sect2 id="odr.sequence.of">
8752 <title>SEQUENCE OF</title>
8754 To handle sequences (arrays) of a specific type, the function
8757 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8758 void *p, int *num, const char *name);
8761 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8762 function of the type. <literal>p</literal> is a pointer to an array of
8763 pointers to your type. <literal>num</literal> is the number of elements
8770 MyArray ::= SEQUENCE OF INTEGER
8773 The C representation might be
8776 typedef struct MyArray
8783 And the function might look like
8786 int myArray(ODR o, MyArray **p, int optional, const char *name)
8788 if (o->direction == ODR_DECODE)
8789 *p = odr_malloc(o, sizeof(**p));
8790 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8791 &(*p)->num_elements, name))
8794 return optional && odr_ok(o);
8798 <sect2 id="odr.choice.types">
8799 <title>CHOICE Types</title>
8801 The choice type is used fairly often in some ASN.1 definitions, so
8802 some work has gone into streamlining its interface.
8805 CHOICE types are handled by the function:
8808 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8812 The <literal>arm</literal> array is used to describe each of the possible
8813 types that the CHOICE type may assume. Internally in your application,
8814 the CHOICE type is represented as a discriminated union. That is, a
8815 C union accompanied by an integer (or enum) identifying the active
8817 <literal>whichp</literal> is a pointer to the union discriminator.
8818 When encoding, it is examined to determine the current type.
8819 When decoding, it is set to reference the type that was found in
8823 The Odr_arm type is defined thus:
8826 typedef struct odr_arm
8837 The interpretation of the fields are:
8841 <term>tagmode</term>
8842 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8843 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8844 to mark no tagging.</para></listitem>
8848 <listitem><para>The value of the discriminator that corresponds to
8849 this CHOICE element. Typically, it will be a #defined constant, or
8850 an enum member.</para></listitem>
8854 <listitem><para>A pointer to a function that implements the type of
8855 the CHOICE member. It may be either a standard &odr; type or a type
8856 defined by yourself.</para></listitem>
8860 <listitem><para>Name of tag.</para></listitem>
8864 A handy way to prepare the array for use by the
8865 <function>odr_choice()</function> function is to
8866 define it as a static, initialized array in the beginning of your
8867 decoding/encoding function. Assume the type definition:
8870 MyChoice ::= CHOICE {
8872 tagged [99] IMPLICIT INTEGER,
8877 Your C type might look like
8880 typedef struct MyChoice
8897 And your function could look like this:
8900 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8902 static Odr_arm arm[] =
8904 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8905 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8907 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8911 if (o->direction == ODR_DECODE)
8912 *p = odr_malloc(o, sizeof(**p);
8914 return optional && odr_ok(o);
8916 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8919 return optional && odr_ok(o);
8923 In some cases (say, a non-optional choice which is a member of a
8924 sequence), you can "embed" the union and its discriminator in the
8925 structure belonging to the enclosing type, and you won't need to
8926 fiddle with memory allocation to create a separate structure to
8927 wrap the discriminator and union.
8930 The corresponding function is somewhat nicer in the Sun XDR interface.
8931 Most of the complexity of this interface comes from the possibility of
8932 declaring sequence elements (including CHOICEs) optional.
8935 The ASN.1 specifications naturally requires that each member of a
8936 CHOICE have a distinct tag, so they can be told apart on decoding.
8937 Sometimes it can be useful to define a CHOICE that has multiple types
8938 that share the same tag. You'll need some other mechanism, perhaps
8939 keyed to the context of the CHOICE type. In effect, we would like to
8940 introduce a level of context-sensitiveness to our ASN.1 specification.
8941 When encoding an internal representation, we have no problem, as long
8942 as each CHOICE member has a distinct discriminator value. For
8943 decoding, we need a way to tell the choice function to look for a
8944 specific arm of the table. The function
8947 void odr_choice_bias(ODR o, int what);
8950 provides this functionality. When called, it leaves a notice for the next
8951 call to <function>odr_choice()</function> to be called on the decoding
8952 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8953 a <literal>which</literal> field equal to <literal>what</literal>
8957 The most important application (perhaps the only one, really) is in
8958 the definition of application-specific EXTERNAL encoders/decoders
8959 which will automatically decode an ANY member given the direct or
8964 <sect1 id="odr.debugging">
8965 <title>Debugging</title>
8967 The protocol modules are suffering somewhat from a lack of diagnostic
8968 tools at the moment. Specifically ways to pretty-print PDUs that
8969 aren't recognized by the system. We'll include something to this end
8970 in a not-too-distant release. In the meantime, what we do when we get
8971 packages we don't understand is to compile the ODR module with
8972 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
8973 information as it processes data units. With this output and the
8974 protocol specification (Z39.50), it is generally fairly easy to see
8979 <chapter id="comstack">
8980 <title>The COMSTACK Module</title>
8981 <sect1 id="comstack.synopsis">
8982 <title>Synopsis (blocking mode)</title>
8983 <programlisting><![CDATA[
8986 int size = 0, length_incoming;
8987 char server_address_str[] = "localhost:9999";
8988 void *server_address_ip;
8991 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
8992 int protocol_package_length = strlen(protocol_package);
8994 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
8996 perror("cs_create"); /* use perror() here since we have no stack yet */
9000 server_address_ip = cs_straddr(stack, server_address_str);
9001 if (!server_address_ip) {
9002 fprintf(stderr, "cs_straddr: address could not be resolved\n");
9006 status = cs_connect(stack, server_address_ip);
9008 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
9012 status = cs_rcvconnect(stack);
9014 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
9018 status = cs_put(stack, protocol_package, protocol_package_length);
9020 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
9024 /* Now get a response */
9025 length_incoming = cs_get(stack, &buf, &size);
9026 if (!length_incoming) {
9027 fprintf(stderr, "Connection closed\n");
9029 } else if (length_incoming < 0) {
9030 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
9035 fwrite(buf, length_incoming, 1, stdout);
9046 <sect1 id="comstack.introduction">
9047 <title>Introduction</title>
9050 subsystem provides a transparent interface to different types of transport
9051 stacks for the exchange of BER-encoded data and HTTP packets.
9052 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
9053 experimental SSL stack are supported, but others may be added in time.
9054 The philosophy of the
9055 module is to provide a simple interface by hiding unused options and
9056 facilities of the underlying libraries. This is always done at the risk
9057 of losing generality, and it may prove that the interface will need
9062 There hasn't been interest in the XTImOSI stack for some years.
9063 Therefore, it is no longer supported.
9067 The interface is implemented in such a fashion that only the
9068 sub-layers constructed to the transport methods that you wish to
9069 use in your application are linked in.
9072 You will note that even though simplicity was a goal in the design,
9073 the interface is still orders of magnitudes more complex than the
9074 transport systems found in many other packages. One reason is that
9075 the interface needs to support the somewhat different requirements of
9076 the different lower-layer communications stacks; another important
9077 reason is that the interface seeks to provide a more or less
9078 industrial-strength approach to asynchronous event-handling.
9079 When no function is allowed to block, things get more complex -
9080 particularly on the server side.
9081 We urge you to have a look at the demonstration client and server
9082 provided with the package. They are meant to be easily readable and
9083 instructive, while still being at least moderately useful.
9086 <sect1 id="comstack.common">
9087 <title>Common Functions</title>
9088 <sect2 id="comstack.managing.endpoints">
9089 <title>Managing Endpoints</title>
9091 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9094 Creates an instance of the protocol stack - a communications endpoint.
9095 The <literal>type</literal> parameter determines the mode
9096 of communication. At present the following values are supported:
9100 <term><literal>tcpip_type</literal></term>
9101 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
9105 <term><literal>ssl_type</literal></term>
9106 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
9107 is experimental and is not fully implemented. If
9108 HTTP is used, this effectively is HTTPS.
9112 <term><literal>unix_type</literal></term>
9113 <listitem><para>Unix socket (unix only). Local Transfer via
9114 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
9115 <manvolnum>7</manvolnum></citerefentry>.
9120 The <function>cs_create</function> function returns a null-pointer
9121 if a system error occurs.
9122 The <literal>blocking</literal> parameter should be one if
9123 you wish the association to operate in blocking mode, zero otherwise.
9124 The <literal>protocol</literal> field should be
9125 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
9126 Protocol <literal>PROTO_SR</literal> is no longer supported.
9129 void cs_close(COMSTACK handle);
9132 Closes the connection (as elegantly as the lower layers will permit),
9133 and releases the resources pointed to by the
9134 <literal>handle</literal>
9136 <literal>handle</literal>
9137 should not be referenced again after this call.
9141 We really need a soft disconnect, don't we?
9145 <sect2 id="comstack.data.exchange">
9146 <title>Data Exchange</title>
9148 int cs_put(COMSTACK handle, char *buf, int len);
9151 Sends <literal>buf</literal> down the wire.
9152 In blocking mode, this function will return only when a full buffer has
9153 been written, or an error has occurred. In nonblocking mode, it's
9154 possible that the function will be unable to send the full buffer
9155 at once, which will be indicated by a return value of 1.
9156 The function will keep track of the number of octets already written; you
9157 should call it repeatedly with the same values of <literal>buf</literal>
9158 and <literal>len</literal>, until the buffer has been transmitted.
9159 When a full buffer has been sent, the function will return 0 for
9160 success. -1 indicates an error condition (see below).
9163 int cs_get(COMSTACK handle, char **buf, int *size);
9166 Receives a PDU or HTTP Response from the peer. Returns the number of
9168 In nonblocking mode, it is possible that not all of the packet can be
9169 read at once. In this case, the function returns 1. To simplify the
9170 interface, the function is
9171 responsible for managing the size of the buffer. It will be reallocated
9172 if necessary to contain large packages, and will sometimes be moved
9173 around internally by the subsystem when partial packages are read. Before
9175 <function>cs_get</function>
9176 for the fist time, the buffer can be initialized to the null pointer,
9177 and the length should also be set to 0 - cs_get will perform a
9178 <function>malloc(2)</function>
9179 on the buffer for you. When a full buffer has been read, the size of
9180 the package is returned (which will always be greater than 1). -1
9181 indicates an error condition.
9184 See also the <function>cs_more()</function> function below.
9187 int cs_more(COMSTACK handle);
9190 The <function>cs_more()</function> function should be used in conjunction
9191 with <function>cs_get</function> and
9192 <function>select(2)</function>.
9193 The <function>cs_get()</function> function will sometimes
9194 (notably in the TCP/IP mode) read more than a single protocol package
9195 off the network. When this happens, the extra package is stored
9196 by the subsystem. After calling <function>cs_get()</function>, and before
9197 waiting for more input, You should always call
9198 <function>cs_more()</function>
9199 to check if there's a full protocol package already read. If
9200 <function>cs_more()</function>
9202 <function>cs_get()</function>
9203 can be used to immediately fetch the new package. For the
9205 subsystem, the function should always return 0, but if you want your
9206 stuff to be protocol independent, you should use it.
9210 The <function>cs_more()</function>
9211 function is required because the RFC1729-method
9212 does not provide a way of separating individual PDUs, short of
9213 partially decoding the BER. Some other implementations will carefully
9214 nibble at the packet by calling
9215 <function>read(2)</function>
9216 several times. This was felt to be too inefficient (or at least
9217 clumsy) - hence the call for this extra function.
9221 int cs_look(COMSTACK handle);
9224 This function is useful when you're operating in nonblocking
9226 <function>select(2)</function>
9227 tells you there's something happening on the line. It returns one of
9228 the following values:
9232 <term>CS_NONE</term>
9234 No event is pending. The data found on the line was not a
9239 <term>CS_CONNECT</term>
9241 A response to your connect request has been received. Call
9242 <function>cs_rcvconnect</function>
9243 to process the event and to finalize the connection establishment.
9247 <term>CS_DISCON</term>
9249 The other side has closed the connection (or maybe sent a disconnect
9250 request - but do we care? Maybe later). Call
9251 <function>cs_close</function> to close your end of the association
9256 <term>CS_LISTEN</term>
9258 A connect request has been received.
9259 Call <function>cs_listen</function> to process the event.
9263 <term>CS_DATA</term>
9265 There's data to be found on the line.
9266 Call <function>cs_get</function> to get it.
9272 You should be aware that even if
9273 <function>cs_look()</function>
9274 tells you that there's an event event pending, the corresponding
9275 function may still return and tell you there was nothing to be found.
9276 This means that only part of a package was available for reading. The
9277 same event will show up again, when more data has arrived.
9281 int cs_fileno(COMSTACK h);
9284 Returns the file descriptor of the association. Use this when
9285 file-level operations on the endpoint are required
9286 (<function>select(2)</function> operations, specifically).
9290 <sect1 id="comstack.client">
9291 <title>Client Side</title>
9293 int cs_connect(COMSTACK handle, void *address);
9296 Initiate a connection with the target at <literal>address</literal>
9297 (more on addresses below). The function will return 0 on success, and 1 if
9298 the operation does not complete immediately (this will only
9299 happen on a nonblocking endpoint). In this case, use
9300 <function>cs_rcvconnect</function> to complete the operation,
9301 when <function>select(2)</function> or <function>poll(2)</function>
9302 reports input pending on the association.
9305 int cs_rcvconnect(COMSTACK handle);
9308 Complete a connect operation initiated by <function>cs_connect()</function>.
9309 It will return 0 on success; 1 if the operation has not yet completed (in
9310 this case, call the function again later); -1 if an error has occurred.
9313 <sect1 id="comstack.server">
9314 <title>Server Side</title>
9316 To establish a server under the <application>inetd</application>
9320 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9324 The <literal>socket</literal> parameter is an established socket (when
9325 your application is invoked from <application>inetd</application>, the
9326 socket will typically be 0.
9327 The following parameters are identical to the ones for
9328 <function>cs_create</function>.
9331 int cs_bind(COMSTACK handle, void *address, int mode)
9334 Binds a local address to the endpoint. Read about addresses below. The
9335 <literal>mode</literal> parameter should be either
9336 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9339 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9342 Call this to process incoming events on an endpoint that has been
9343 bound in listening mode. It will return 0 to indicate that the connect
9344 request has been received, 1 to signal a partial reception, and -1 to
9345 indicate an error condition.
9348 COMSTACK cs_accept(COMSTACK handle);
9351 This finalizes the server-side association establishment, after
9352 cs_listen has completed successfully. It returns a new connection
9353 endpoint, which represents the new association. The application will
9354 typically wish to fork off a process to handle the association at this
9355 point, and continue listen for new connections on the old
9356 <literal>handle</literal>.
9359 You can use the call
9362 const char *cs_addrstr(COMSTACK);
9365 on an established connection to retrieve the host-name of the remote host.
9369 You may need to use this function with some care if your
9370 name server service is slow or unreliable
9374 <sect1 id="comstack.addresses">
9375 <title>Addresses</title>
9377 The low-level format of the addresses are different depending on the
9378 mode of communication you have chosen. A function is provided by each
9379 of the lower layers to map a user-friendly string-form address to the
9380 binary form required by the lower layers.
9383 void *cs_straddr(COMSTACK handle, const char *str);
9386 The format for TCP/IP and SSL addresses is:
9389 <host> [ ':' <portnum> ]
9392 The <literal>hostname</literal> can be either a domain name or an
9393 IP address. The port number, if omitted, defaults to 210.
9396 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9397 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9398 IPV4 binding as well (bindv6only=0),
9399 The special hostname <literal>@4</literal> binds to
9400 <literal>INADDR_ANY</literal> (IPV4 only listener).
9401 The special hostname <literal>@6</literal> binds to
9402 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9405 For UNIX sockets, the format of an address is the socket filename.
9408 When a connection has been established, you can use
9411 const char *cs_addrstr(COMSTACK h);
9414 to retrieve the host name of the peer system. The function returns
9415 a pointer to a static area, which is overwritten on the next call
9419 A fairly recent addition to the &comstack; module is the utility
9423 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9426 which is just a wrapper for <function>cs_create</function> and
9427 <function>cs_straddr</function>. The <parameter>str</parameter>
9428 is similar to that described for <function>cs_straddr</function>
9429 but with a prefix denoting the &comstack; type. Prefixes supported
9430 are <literal>tcp:</literal>, <literal>unix:</literal> and
9431 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9432 If no prefix is given, then TCP/IP is used.
9433 The <parameter>blocking</parameter> is passed to
9434 function <function>cs_create</function>. The third parameter
9435 <parameter>vp</parameter> is a pointer to &comstack; stack type
9437 Parameter <parameter>vp</parameter> is reserved for future use.
9438 Set it to <literal>NULL</literal>.
9441 <sect1 id="comstack.ssl">
9445 void *cs_get_ssl(COMSTACK cs);
9447 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9448 is not of type SSL, NULL is returned.
9452 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9454 Sets SSL context for comstack. The parameter is expected to be of type
9455 <literal>SSL_CTX *</literal>. This function should be called just
9456 after comstack has been created (before connect, bind, etc).
9457 This function returns 1 for success; 0 for failure.
9461 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9463 Sets SSL certificate for comstack as a PEM file. This function
9464 returns 1 for success; 0 for failure.
9468 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9470 This function returns the peer certificate. If successful,
9471 <literal>*buf</literal> and <literal>*len</literal> holds
9472 X509 buffer and length respectively. Buffer should be freed
9473 with <literal>xfree</literal>. This function returns 1 for success;
9477 <sect1 id="comstack.diagnostics">
9478 <title>Diagnostics</title>
9480 All functions return -1 if an error occurs. Typically, the functions
9481 will return 0 on success, but the data exchange functions
9482 (<function>cs_get</function>, <function>cs_put</function>,
9483 <function>cs_more</function>) follow special rules. Consult their
9487 The error code for the COMSTACK can be retrieved using C macro
9488 <function>cs_errno</function> which will return one
9489 of the error codes <literal>CSYSERR</literal>,
9490 <literal>CSOUTSTATE</literal>,
9491 <literal>CSNODATA</literal>, ...
9494 int cs_errno(COMSTACK handle);
9497 You can the textual representation of the error code
9498 by using <function>cs_errmsg</function> - which
9499 works like <function>strerror(3)</function>
9502 const char *cs_errmsg(int n);
9505 It is also possible to get straight to the textual represenataion
9506 without the error code by using
9507 <function>cs_strerror</function>.
9510 const char *cs_strerror(COMSTACK h);
9513 <sect1 id="comstack.summary">
9514 <title>Summary and Synopsis</title>
9516 #include <yaz/comstack.h>
9518 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9519 #include <yaz/unix.h> /* this is for UNIX socket support */
9521 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9523 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9525 COMSTACK cs_create_host(const char *str, int blocking,
9528 int cs_bind(COMSTACK handle, int mode);
9530 int cs_connect(COMSTACK handle, void *address);
9532 int cs_rcvconnect(COMSTACK handle);
9534 int cs_listen(COMSTACK handle);
9536 COMSTACK cs_accept(COMSTACK handle);
9538 int cs_put(COMSTACK handle, char *buf, int len);
9540 int cs_get(COMSTACK handle, char **buf, int *size);
9542 int cs_more(COMSTACK handle);
9544 void cs_close(COMSTACK handle);
9546 int cs_look(COMSTACK handle);
9548 void *cs_straddr(COMSTACK handle, const char *str);
9550 const char *cs_addrstr(COMSTACK h);
9555 <chapter id="future">
9556 <title>Future Directions</title>
9558 We have a new and better version of the front-end server on the drawing
9559 board. Resources and external commitments will govern when we'll be
9560 able to do something real with it. Features should include greater
9561 flexibility, greater support for access/resource control, and easy
9562 support for Explain (possibly with Zebra as an extra database engine).
9565 &yaz; is a BER toolkit and as such should support all protocols
9566 out there based on that. We'd like to see running ILL applications.
9567 It shouldn't be that hard. Another thing that would be interesting is
9568 LDAP. Maybe a generic framework for doing IR using both LDAP and
9569 Z39.50 transparently.
9572 The SOAP implementation is incomplete. In the future we hope
9573 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9574 The authors of libxml2 are already working on XML Schema / RelaxNG
9575 compilers so this may not be too hard.
9578 It would be neat to have a proper module mechanism for the Generic
9579 Frontend Server so that backend would be dynamically
9580 loaded (as shared objects / DLLs).
9583 Other than that, &yaz; generally moves in the directions which appear to
9584 make the most people happy (including ourselves, as prime users of the
9585 software). If there's something you'd like to see in here, then drop
9586 us a note and let's see what we can come up with.
9589 <reference id="reference">
9590 <title>Reference</title>
9591 <partintro id="reference-introduction">
9593 The material in this chapter is drawn directly from the individual
9599 <appendix id="list-oids">
9600 <title>List of Object Identifiers</title>
9602 These is a list of object identifiers that are built into YAZ.
9606 <appendix id="bib1-diagnostics">
9607 <title>Bib-1 diagnostics</title>
9609 List of Bib-1 diagnostics that are known to YAZ.
9613 <appendix id="sru-diagnostics">
9614 <title>SRU diagnostics</title>
9616 List of SRU diagnostics that are known to YAZ.
9620 <appendix id="license">
9621 <title>License</title>
9622 <sect1 id="license.indexdata">
9623 <title>Index Data Copyright</title>
9625 Copyright © ©right-year; Index Data.
9628 All rights reserved.
9631 Redistribution and use in source and binary forms, with or without
9632 modification, are permitted provided that the following conditions are met:
9637 Redistributions of source code must retain the above copyright
9638 notice, this list of conditions and the following disclaimer.
9643 Redistributions in binary form must reproduce the above copyright
9644 notice, this list of conditions and the following disclaimer in the
9645 documentation and/or other materials provided with the distribution.
9650 Neither the name of Index Data nor the names of its contributors
9651 may be used to endorse or promote products derived from this
9652 software without specific prior written permission.
9657 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9658 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9659 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9660 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9661 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9662 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9663 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9664 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9665 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9666 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9671 <appendix id="indexdata">
9672 <title>About Index Data</title>
9674 Index Data is a consulting and software-development enterprise that
9675 specializes in library and information management systems. Our
9676 interests and expertise span a broad range of related fields, and one
9677 of our primary, long-term objectives is the development of a powerful
9678 information management
9679 system with open network interfaces and hyper-media capabilities.
9681 We make this software available free of charge, on a fairly unrestrictive
9682 license; as a service to the networking community, and to further the
9683 development of quality software for open network communication.
9685 We'll be happy to answer questions about the software, and about ourselves
9691 <street>Amagerfælledvej 56</street>
9692 <postcode>2300 Copenhagen S</postcode>
9693 <country>Denmark</country>
9694 Email <email>info@indexdata.dk</email>
9698 The Hacker's Jargon File has the following to say about the
9700 prefix "YA" in the name of a software product.
9704 Yet Another. adj. 1. Of your own work: A
9705 humorous allusion often used in titles to acknowledge that the
9706 topic is not original, though the content is. As in "Yet Another
9707 AI Group" or "Yet Another Simulated Annealing Algorithm".
9709 others' work: Describes something of which there are already far
9714 <appendix id="credits">
9715 <title>Credits</title>
9717 This appendix lists individuals that have contributed in the development
9718 of &yaz;. Some have contributed with code, while others have provided bug
9719 fixes or suggestions. If we're missing somebody, of if you, for
9720 whatever reason, don't like to be listed here, let us know.
9730 Morten Bøgeskov
9751 Mads Bondo Dydensborg
9760 Morten Garkier Hendriksen
9817 Tom André Øverland
9823 <!-- Keep this comment at the end of the file
9826 nxml-child-indent: 1