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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.
710 <literal>--with-redis</literal>
713 <para>&yaz; will be linked with the hiredis C library
714 to allow for result-set caching for ZOOM on a
715 <ulink url="&url.redis;">redis</ulink> server.
716 The prefix can not be given. Note that YAZ will only search
717 for hiredis if Libgcrypt is also enabled.
725 When configured, build the software by typing:
731 The following files are generated by the make process:
734 <term><filename>src/libyaz.la</filename></term>
736 Main &yaz; library. This is no ordinary library. It's
738 By default, &yaz; creates a static library in
739 <filename>lib/.libs/libyaz.a</filename>.
743 <term><filename>src/libyaz_server.la</filename></term>
745 Generic Frontend server. This is an add-on for libyaz.la.
746 Code in this library uses POSIX threads functions - if POSIX
747 threads are available on the platform.
751 <term><filename>src/libyaz_icu.la</filename></term>
753 Functions that wrap the ICU library.
757 <term><filename>ztest/yaz-ztest</filename></term>
758 <listitem><para>Test Z39.50 server.
762 <term><filename>client/yaz-client</filename></term>
763 <listitem><para>Z39.50 client for testing the protocol.
764 See chapter <link linkend="yaz-client">
765 YAZ client</link> for more information.
769 <term><filename>util/yaz-config</filename></term>
770 <listitem><para>A Bourne-shell script, generated by configure, that
771 specifies how external applications should compile - and link with
776 <term><filename>util/yaz-asncomp</filename></term>
777 <listitem><para>The ASN.1 compiler for &yaz;. Requires the
778 Tcl Shell, <application>tclsh</application>, in
779 <literal>PATH</literal> to operate.
783 <term><filename>util/yaz-iconv</filename></term>
784 <listitem><para>This program converts data in one character set to
785 another. This command exercises the YAZ character set
790 <term><filename>util/yaz-marcdump</filename></term>
791 <listitem><para>This program parses ISO2709 encoded MARC records
792 and prints them in line-format or XML.
796 <term><filename>util/yaz-icu</filename></term>
797 <listitem><para>This program exposes the ICU wrapper library if that
798 is enabled for YAZ. Only if ICU is available this program is
803 <term><filename>util/yaz-url</filename></term>
804 <listitem><para>This program is a simple HTTP page fetcher ala
809 <term><filename>zoom/zoomsh</filename></term>
811 A simple shell implemented on top of the
812 <link linkend="zoom">ZOOM</link> functions.
813 The shell is a command line application that allows you to enter
814 simple commands to perform ZOOM operations.
818 <term><filename>zoom/zoomtst1</filename>,
819 <filename>zoom/zoomtst2</filename>, ..</term>
821 Several small applications that demonstrates the ZOOM API.
827 If you wish to install &yaz; in system directories
828 <filename>/usr/local/bin</filename>,
829 <filename>/usr/local/lib</filename> .. etc, you can type:
835 You probably need to have root access in order to perform this.
836 You must specify the <literal>--prefix</literal> option for configure if
837 you wish to install &yaz; in other directories than the default
838 <filename>/usr/local/</filename>.
841 If you wish to perform an un-installation of &yaz;, use:
847 This will only work if you haven't reconfigured &yaz; (and therefore
848 changed installation prefix). Note that uninstall will not
849 remove directories created by make install, e.g.
850 <filename>/usr/local/include/yaz</filename>.
853 <sect2 id="installation-linking-yaz-unix">
854 <title>How to make apps using YAZ on UNIX</title>
856 This section describes how to compile - and link your own
857 applications using the &yaz; toolkit.
858 If you're used to Makefiles this shouldn't be hard. As for
859 other libraries you have used before, you have to set a proper include
860 path for your C/C++ compiler and specify the location of
861 &yaz; libraries. You can do it by hand, but generally we suggest
862 you use the <filename>yaz-config</filename> that is generated
863 by <filename>configure</filename>. This is especially
864 important if you're using the threaded version of &yaz; which
865 require you to pass more options to your linker/compiler.
868 The <filename>yaz-config</filename> script accepts command line
869 options that makes the <filename>yaz-config</filename> script print
870 options that you should use in your make process.
871 The most important ones are:
872 <literal>--cflags</literal>, <literal>--libs</literal>
873 which prints C compiler flags, and linker flags respectively.
876 A small and complete <literal>Makefile</literal> for a C
877 application consisting of one source file,
878 <filename>myprog.c</filename>, may look like this:
880 YAZCONFIG=/usr/local/bin/yaz-config
881 CFLAGS=`$(YAZCONFIG) --cflags`
882 LIBS=`$(YAZCONFIG) --libs`
884 $(CC) $(CFLAGS) -o myprog myprog.o $(LIBS)
888 The CFLAGS variable consists of a C compiler directive that will set
889 the include path to the <emphasis>parent</emphasis> directory
890 of <filename>yaz</filename>. That is, if &yaz; header files were
891 installed in <filename>/usr/local/include/yaz</filename>,
892 then include path is set to <filename>/usr/local/include</filename>.
893 Therefore, in your applications you should use
895 #include <yaz/proto.h>
897 and <emphasis>not</emphasis>
899 #include <proto.h>
903 For Libtool users, the <filename>yaz-config</filename> script provides
904 a different variant of option <literal>--libs</literal>, called
905 <literal>--lalibs</literal> that returns the name of the
906 Libtool archive(s) for &yaz; rather than the ordinary ones.
909 For applications using the threaded version of &yaz;,
910 specify <literal>threads</literal> after the
911 other options. When <literal>threads</literal> is given,
912 more flags and linker flags will be printed by
913 <filename>yaz-config</filename>. If our previous example was
914 using threads, you'd have to modify the lines that set
915 <literal>CFLAGS</literal> and <literal>LIBS</literal> as
918 CFLAGS=`$(YAZCONFIG) --cflags threads`
919 LIBS=`$(YAZCONFIG) --libs threads`
921 There is no need specify POSIX thread libraries in your Makefile.
922 The <literal>LIBS</literal> variable includes that as well.
926 <sect1 id="installation.win32">
928 <para>The easiest way to install YAZ on Windows is by downloading
930 <ulink url="&url.yaz.download.win32;">here</ulink>.
931 The installer comes with source too - in case you wish to
932 compile YAZ with different compiler options, etc.
935 <sect2 id="installation.win32.source">
936 <title>Compiling from Source on WIN32</title>
938 &yaz; is shipped with "makefiles" for the NMAKE tool that comes
939 with <ulink url="&url.vstudio;">
940 Microsoft Visual Studio</ulink>. It has been tested with
941 Microsoft Visual Studio 2003/2005/2008.
944 Start a command prompt and switch the sub directory
945 <filename>WIN</filename> where the file <filename>makefile</filename>
946 is located. Customize the installation by editing the
947 <filename>makefile</filename> file (for example by using notepad).
948 The following summarizes the most important settings in that file:
951 <term><literal>DEBUG</literal></term>
953 If set to 1, the software is
954 compiled with debugging libraries (code generation is
955 multi-threaded debug DLL).
956 If set to 0, the software is compiled with release libraries
957 (code generation is multi-threaded DLL).
961 <term><literal>HAVE_TCL</literal>, <literal>TCL</literal></term>
963 If <literal>HAVE_TCL</literal> is set to 1, nmake will
964 use the ASN.1 compiler (<ulink url="&url.tcl;">Tcl</ulink> based).
965 You must set <literal>TCL</literal> to the full path of the Tcl
966 interpreter. A Windows version of Tcl is part of
967 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
970 If you do not have Tcl installed, set
971 <literal>HAVE_TCL</literal> to 0.
975 <term><literal>HAVE_BISON</literal>,
976 <literal>BISON</literal></term>
978 If GNU Bison is present, you might set <literal>HAVE_BISON</literal>
979 to 1 and specify the Bison executable in <literal>BISON</literal>.
980 Bison is only required if you use the Git version of
981 YAZ or if you modify the grammar for CQL
982 (<filename>cql.y</filename>).
985 A Windows version of GNU Bison is part of
986 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
990 <term><literal>HAVE_ICONV</literal>,
991 <literal>ICONV_DIR</literal></term>
993 If <literal>HAVE_ICONV</literal> is set to 1, YAZ is compiled
994 with iconv support. In this configuration, set
995 <literal>ICONV_DIR</literal> to the iconv source directory.
999 <term><literal>HAVE_LIBXML2</literal>,
1000 <literal>LIBXML2_DIR</literal></term>
1003 If <literal>HAVE_LIBXML2</literal> is set to 1, YAZ is compiled
1004 with SRU support. In this configuration, set
1005 <literal>LIBXML2_DIR</literal> to the
1006 <ulink url="&url.libxml2;">libxml2</ulink> source directory
1008 <literal>ZLIB_DIR</literal> to the zlib directory.
1011 Windows versions of libxslt, libxml2, zlib and iconv can be found
1012 <ulink url="&url.libxml2.download.win32;">
1013 Igor Zlatković' site</ulink>.
1017 YAZ is not using zlib but libxml2 is depending on it.
1023 <term><literal>HAVE_LIBXSLT</literal>,
1024 <literal>LIBXSLT_DIR</literal></term>
1027 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1028 with XSLT support. In this configuration, set
1029 <literal>LIBXSLT_DIR</literal> to the
1030 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1034 libxslt depends libxml2.
1040 <term><literal>HAVE_ICU</literal>,
1041 <literal>ICU_DIR</literal></term>
1044 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1045 with <ulink url="&url.icu;">ICU</ulink> support.
1046 In this configuration, set
1047 <literal>ICU_DIR</literal> to the
1048 <ulink url="&url.icu;">ICU</ulink> source directory.
1055 When satisfied with the settings in the makefile, type
1062 If the <filename>nmake</filename> command is not found on your system
1063 you probably haven't defined the environment variables required to
1064 use that tool. To fix that, find and run the batch file
1065 <filename>vcvars32.bat</filename>. You need to run it from within
1066 the command prompt or set the environment variables "globally";
1067 otherwise it doesn't work.
1071 If you wish to recompile &yaz; - for example if you modify
1072 settings in the <filename>makefile</filename> you can delete
1073 object files, etc by running.
1079 The following files are generated upon successful compilation:
1082 <term><filename>bin/yaz&soversion;.dll</filename> /
1083 <filename>bin/yaz&soversion;d.dll</filename></term>
1085 &yaz; Release/Debug DLL.
1089 <term><filename>lib/yaz&soversion;.lib</filename> /
1090 <filename>lib/yaz&soversion;d.lib</filename></term>
1092 Import library for <filename>yaz&soversion;.dll</filename> /
1093 <filename>yaz&soversion;d.dll</filename>.
1097 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1098 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1100 Release/Debug DLL for condition variable utilities (condvar.c).
1104 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1105 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1107 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1108 <filename>yaz_cond&soversion;d.dll</filename>.
1112 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1113 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1115 Release/Debug DLL for the ICU wrapper utility.
1116 Only build if HAVE_ICU is 1.
1120 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1121 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1123 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1124 <filename>yaz_icu&soversion;d.dll</filename>.
1128 <term><filename>bin/yaz-ztest.exe</filename></term>
1130 Z39.50 multi-threaded test/example server. It's a WIN32
1131 console application.
1135 <term><filename>bin/yaz-client.exe</filename></term>
1137 &yaz; Z39.50 client application. It's a WIN32 console application.
1138 See chapter <link linkend="yaz-client">YAZ client</link> for more
1143 <term><filename>bin/yaz-icu.exe</filename></term>
1144 <listitem><para>This program exposes the ICU wrapper library if that
1145 is enabled for YAZ. Only if ICU is available this program is
1150 <term><filename>bin/zoomsh.exe</filename></term>
1152 Simple console application implemented on top of the
1153 <link linkend="zoom">ZOOM</link> functions.
1154 The application is a command line shell that allows you to enter
1155 simple commands to perform ZOOM operations.
1159 <term><filename>bin/zoomtst1.exe</filename>,
1160 <filename>bin/zoomtst2.exe</filename>, ..</term>
1162 Several small applications that demonstrates the ZOOM API.
1169 <sect2 id="installation-linking-yaz-win32">
1170 <title>How to make apps using YAZ on WIN32</title>
1172 This section will go though the process of linking your WIN32
1173 applications with &yaz;.
1176 Some people are confused by the fact that we use the nmake
1177 tool to build &yaz;. They think they have to do that too - in order
1178 to make their WIN32 applications work with &yaz;. The good news is that
1179 you don't have to. You can use the integrated environment of
1180 Visual Studio if desired for your own application.
1183 When setting up a project or Makefile you have to set the following:
1186 <term>include path</term>
1188 Set it to the <filename>include</filename> directory of &yaz;.
1192 <term>import library <filename>yaz&soversion;.lib</filename></term>
1194 You must link with this library. It's located in the
1195 sub directory <filename>lib</filename> of &yaz;.
1196 If you want to link with the debug version of &yaz;, you must
1197 link against <filename>yaz&soversion;d.lib</filename> instead.
1201 <term>dynamic link library
1202 <filename>yaz&soversion;.dll</filename>
1205 This DLL must be in your execution path when you invoke
1206 your application. Specifically, you should distribute this
1207 DLL with your application.
1216 ### Still to document:
1217 ZOOM_connection_errcode(c)
1218 ZOOM_connection_errmsg(c)
1219 ZOOM_connection_addinfo(c)
1220 ZOOM_connection_addinfo(c)
1221 ZOOM_connection_diagset(c);
1222 ZOOM_connection_save_apdu_wrbuf
1223 ZOOM_diag_str(error)
1224 ZOOM_resultset_record_immediate(s, pos)
1225 ZOOM_resultset_cache_reset(r)
1226 ZOOM_options_set_callback(opt, function, handle)
1227 ZOOM_options_create_with_parent2(parent1, parent2)
1228 ZOOM_options_getl(opt, name, len)
1229 ZOOM_options_setl(opt, name, value, len)
1230 ZOOM_options_get_bool(opt, name, defa)
1231 ZOOM_options_get_int(opt, name, defa)
1232 ZOOM_options_set_int(opt, name, value)
1237 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1238 an initiative started by Mike Taylor (Mike is from the UK, which
1239 explains the peculiar name of the model). The goal of &zoom; is to
1240 provide a common Z39.50 client API not bound to a particular
1241 programming language or toolkit.
1244 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1245 You can make SRU ZOOM connections by specifying scheme
1246 <literal>http://</literal> for the hostname for a connection.
1247 The dialect of SRU used is specified by the value of the
1248 connection's <literal>sru</literal> option, which may be SRU over
1249 HTTP GET (<literal>get</literal>),
1250 SRU over HTTP POST (<literal>post</literal>), (SRU over
1251 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1252 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1253 Using the facility for embedding options in target strings, a
1254 connection can be forced to use SRU rather the SRW (the default) by
1255 prefixing the target string with <literal>sru=get,</literal>, like this:
1256 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1259 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1260 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1261 HTTP based protocols.
1264 The lack of a simple Z39.50 client API for &yaz; has become more
1265 and more apparent over time. So when the first &zoom; specification
1267 an implementation for &yaz; was quickly developed. For the first time, it is
1268 now as easy (or easier!) to develop clients than servers with &yaz;. This
1269 chapter describes the &zoom; C binding. Before going further, please
1270 reconsider whether C is the right programming language for the job.
1271 There are other language bindings available for &yaz;, and still
1273 are in active development. See the
1274 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1278 In order to fully understand this chapter you should read and
1279 try the example programs <literal>zoomtst1.c</literal>,
1280 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1284 The C language misses features found in object oriented languages
1285 such as C++, Java, etc. For example, you'll have to manually,
1286 destroy all objects you create, even though you may think of them as
1287 temporary. Most objects has a <literal>_create</literal> - and a
1288 <literal>_destroy</literal> variant.
1289 All objects are in fact pointers to internal stuff, but you don't see
1290 that because of typedefs. All destroy methods should gracefully ignore a
1291 <literal>NULL</literal> pointer.
1294 In each of the sections below you'll find a sub section called
1295 protocol behavior, that describes how the API maps to the Z39.50
1298 <sect1 id="zoom-connections">
1299 <title>Connections</title>
1300 <para>The Connection object is a session with a target.
1303 #include <yaz/zoom.h>
1305 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1307 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1309 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1311 void ZOOM_connection_destroy(ZOOM_connection c);
1314 Connection objects are created with either function
1315 <function>ZOOM_connection_new</function> or
1316 <function>ZOOM_connection_create</function>.
1317 The former creates and automatically attempts to establish a network
1318 connection with the target. The latter doesn't establish
1319 a connection immediately, thus allowing you to specify options
1320 before establishing network connection using the function
1321 <function>ZOOM_connection_connect</function>.
1322 If the port number, <literal>portnum</literal>, is zero, the
1323 <literal>host</literal> is consulted for a port specification.
1324 If no port is given, 210 is used. A colon denotes the beginning of
1325 a port number in the host string. If the host string includes a
1326 slash, the following part specifies a database for the connection.
1329 You can prefix the host with a scheme followed by colon. The
1330 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1331 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1332 but can overridded to use SRU/post, SRW and the Solr protocol.
1335 You can prefix the scheme-qualified host-string with one or more
1337 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1338 sequences, each of which represents an option to be set into the
1339 connection structure <emphasis>before</emphasis> the
1340 protocol-level connection is forged and the initialization
1341 handshake takes place. This facility can be used to provide
1342 authentication credentials, as in host-strings such as:
1343 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1346 Connection objects should be destroyed using the function
1347 <function>ZOOM_connection_destroy</function>.
1350 void ZOOM_connection_option_set(ZOOM_connection c,
1351 const char *key, const char *val);
1353 void ZOOM_connection_option_setl(ZOOM_connection c,
1355 const char *val, int len);
1357 const char *ZOOM_connection_option_get(ZOOM_connection c,
1359 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1364 The functions <function>ZOOM_connection_option_set</function> and
1365 <function>ZOOM_connection_option_setl</function> allows you to
1366 set an option given by <parameter>key</parameter> to the value
1367 <parameter>value</parameter> for the connection.
1368 For <function>ZOOM_connection_option_set</function>, the
1369 value is assumed to be a 0-terminated string. Function
1370 <function>ZOOM_connection_option_setl</function> specifies a
1371 value of a certain size (len).
1374 Functions <function>ZOOM_connection_option_get</function> and
1375 <function>ZOOM_connection_option_getl</function> returns
1376 the value for an option given by <parameter>key</parameter>.
1378 <table id="zoom-connection-options" frame="top">
1379 <title>ZOOM Connection Options</title>
1381 <colspec colwidth="4*" colname="name"></colspec>
1382 <colspec colwidth="7*" colname="description"></colspec>
1383 <colspec colwidth="3*" colname="default"></colspec>
1386 <entry>Option</entry>
1387 <entry>Description</entry>
1388 <entry>Default</entry>
1393 implementationName</entry><entry>Name of Your client
1394 </entry><entry>none</entry></row>
1396 user</entry><entry>Authentication user name
1397 </entry><entry>none</entry></row>
1399 group</entry><entry>Authentication group name
1400 </entry><entry>none</entry></row>
1402 password</entry><entry>Authentication password.
1403 </entry><entry>none</entry></row>
1405 authenticationMode</entry><entry>How authentication is encoded.
1406 </entry><entry>basic</entry></row>
1408 host</entry><entry>Target host. This setting is "read-only".
1409 It's automatically set internally when connecting to a target.
1410 </entry><entry>none</entry></row>
1412 proxy</entry><entry>Proxy host. If set, the logical host
1413 is encoded in the otherInfo area of the Z39.50 Init PDU
1414 with OID 1.2.840.10003.10.1000.81.1.
1415 </entry><entry>none</entry></row>
1417 clientIP</entry><entry>Client IP. If set, is
1418 encoded in the otherInfo area of a Z39.50 PDU with OID
1419 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1420 of a client. Is used of ZOOM is used in a gateway of some sort.
1421 </entry><entry>none</entry></row>
1423 async</entry><entry>If true (1) the connection operates in
1424 asynchronous operation which means that all calls are non-blocking
1426 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1427 </entry><entry>0</entry></row>
1429 maximumRecordSize</entry><entry> Maximum size of single record.
1430 </entry><entry>1 MB</entry></row>
1432 preferredMessageSize</entry><entry> Maximum size of multiple records.
1433 </entry><entry>1 MB</entry></row>
1435 lang</entry><entry> Language for negotiation.
1436 </entry><entry>none</entry></row>
1438 charset</entry><entry> Character set for negotiation.
1439 </entry><entry>none</entry></row>
1441 serverImplementationId</entry><entry>
1442 Implementation ID of server. (The old targetImplementationId
1443 option is also supported for the benefit of old applications.)
1444 </entry><entry>none</entry></row>
1446 targetImplementationName</entry><entry>
1447 Implementation Name of server. (The old
1448 targetImplementationName option is also supported for the
1449 benefit of old applications.)
1450 </entry><entry>none</entry></row>
1452 serverImplementationVersion</entry><entry>
1453 Implementation Version of server. (the old
1454 targetImplementationVersion option is also supported for the
1455 benefit of old applications.)
1456 </entry><entry>none</entry></row>
1458 databaseName</entry><entry>One or more database names
1459 separated by character plus (<literal>+</literal>), which to
1460 be used by subsequent search requests on this Connection.
1461 </entry><entry>Default</entry></row>
1463 piggyback</entry><entry>True (1) if piggyback should be
1464 used in searches; false (0) if not.
1465 </entry><entry>1</entry></row>
1467 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1468 value, then target will return all records using small element set name
1469 </entry><entry>0</entry></row>
1471 largeSetLowerBound</entry><entry>If hits is greater than this
1472 value, the target will return no records.
1473 </entry><entry>1</entry></row>
1475 mediumSetPresentNumber</entry><entry>This value represents
1476 the number of records to be returned as part of a search when when
1477 hits is less than or equal to large set lower bound and if hits
1478 is greater than small set upper bound.
1479 </entry><entry>0</entry></row>
1481 smallSetElementSetName</entry><entry>
1482 The element set name to be used for small result sets.
1483 </entry><entry>none</entry></row>
1485 mediumSetElementSetName</entry><entry>
1486 The element set name to be for medium-sized result sets.
1487 </entry><entry>none</entry></row>
1489 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1490 After a successful Init, these options may be interrogated to
1491 discover whether the server claims to support the specified
1493 </entry><entry>none</entry></row>
1495 <entry>sru</entry><entry>
1496 SRU/Solr transport type. Must be either <literal>soap</literal>,
1497 <literal>get</literal>, <literal>post</literal>, or
1498 <literal>solr</literal>.
1499 </entry><entry>soap</entry></row>
1501 sru_version</entry><entry>
1502 SRU/SRW version. Should be <literal>1.1</literal>, or
1503 <literal>1.2</literal>. This is , prior to connect, the version
1504 to offer (highest version). And following connect (in fact
1505 first operation), holds the negotiated version with the server
1506 (same or lower version).
1507 </entry><entry>1.2</entry></row>
1508 <row id="zoom.facets.option"><entry>
1509 facets</entry><entry>
1510 Requested or recommend facets may be given before a search is sent.
1511 The value of this setting is described in <xref linkend="facets"/>
1512 For inspection of the facets returned, refer to the functions
1513 described in <xref linkend="zoom.facets"/>.
1514 </entry><entry>none</entry></row>
1516 apdulog</entry><entry>
1517 If set to a true value such as "1", a log of low-level
1518 protocol packets is emitted on standard error stream. This
1519 can be very useful for debugging.
1520 </entry><entry>0</entry></row>
1522 saveAPDU</entry><entry>
1523 If set to a true value such as "1", a log of low-level
1524 protocol packets is saved. The log can be retrieved by reading
1525 option APDU. Setting saveAPDU always has the side effect of
1526 resetting the currently saved log. This setting is
1527 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1528 It is only recognized in
1529 <function>ZOOM_connection_option_set</function>.
1530 </entry><entry>0</entry></row>
1533 Returns the log of protocol packets. Will be empty if logging
1534 is not enabled (see saveAPDU above). This setting is
1535 <emphasis>read-only</emphasis>. It is only recognized if used
1536 in call to <function>ZOOM_connection_option_get</function> or
1537 <function>ZOOM_connection_option_getl</function>.
1538 </entry><entry></entry></row>
1540 memcached</entry><entry>
1541 If given and non-empty,
1542 <ulink url="&url.libmemcached;">libMemcached</ulink>
1543 will be configured for the connection.
1544 This option is inspected by ZOOM when a connection is established.
1545 If the <literal>memcached</literal> option is given
1546 and YAZ is compiled without libMemcached support, an internal
1547 diagnostic (10018) will be thrown.
1548 libMemcached support is available for YAZ 5.0.13 or later. If this
1549 option is supplied for an earlier version of YAZ, it is
1550 <emphasis>ignored</emphasis>.
1551 The value of this option is a string passed verbatim to
1552 the <function>memcached</function> function part of libMemcached.
1554 <ulink url="http://manned.org/memcached.3">memcached(3)</ulink>.
1555 Earlier versions of libMemcached
1556 do not offer this function. In this case only the option
1557 <literal>--server=</literal><replaceable>host</replaceable> may
1558 be given (YAZ emulates that part of libMemcached).
1559 </entry><entry>none</entry></row>
1561 redis</entry><entry>
1562 If given and non-empty,
1563 a <ulink url="&url.redis;">redis</ulink> context will be created
1565 This option is inspected by ZOOM when a connection is established.
1566 If the <literal>redis</literal> option is given
1567 and YAZ is compiled without redis support, an internal
1568 diagnostic (10018) will be thrown.
1569 redis support is available for YAZ 5.2.0 or later. If this
1570 option is supplied for an earlier version of YAZ, it is
1571 <emphasis>ignored</emphasis>.
1572 The value of this option is a set options, similar to that
1573 of the memcached function. At this stage only --server=host[:port]
1574 is supported. Later versions of YAZ might honor expiry for various
1575 items and other things that tune the redis usage.
1576 </entry><entry>none</entry></row>
1581 If either option <literal>lang</literal> or <literal>charset</literal>
1583 <ulink url="&url.z39.50.charneg;">
1584 Character Set and Language Negotiation</ulink> is in effect.
1587 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1588 const char **addinfo);
1589 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1590 const char **addinfo, const char **dset);
1593 Function <function>ZOOM_connection_error</function> checks for
1594 errors for the last operation(s) performed. The function returns
1595 zero if no errors occurred; non-zero otherwise indicating the error.
1596 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1597 holds messages for the error and additional-info if passed as
1598 non-<literal>NULL</literal>. Function
1599 <function>ZOOM_connection_error_x</function> is an extended version
1600 of <function>ZOOM_connection_error</function> that is capable of
1601 returning name of diagnostic set in <parameter>dset</parameter>.
1603 <sect2 id="zoom-connection-z39.50">
1604 <title>Z39.50 Protocol behavior</title>
1606 The calls <function>ZOOM_connection_new</function> and
1607 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1608 connection and sends an Initialize Request to the target if
1609 possible. In addition, the calls waits for an Initialize Response
1610 from the target and the result is inspected (OK or rejected).
1613 If <literal>proxy</literal> is set then the client will establish
1614 a TCP/IP connection with the peer as specified by the
1615 <literal>proxy</literal> host and the hostname as part of the
1616 connect calls will be set as part of the Initialize Request.
1617 The proxy server will then "forward" the PDU's transparently
1618 to the target behind the proxy.
1621 For the authentication parameters, if option <literal>user</literal>
1622 is set and both options <literal>group</literal> and
1623 <literal>pass</literal> are unset, then Open style
1624 authentication is used (Version 2/3) in which case the username
1625 is usually followed by a slash, then by a password.
1626 If either <literal>group</literal>
1627 or <literal>pass</literal> is set then idPass authentication
1628 (Version 3 only) is used. If none of the options are set, no
1629 authentication parameters are set as part of the Initialize Request
1633 When option <literal>async</literal> is 1, it really means that
1634 all network operations are postponed (and queued) until the
1635 function <literal>ZOOM_event</literal> is invoked. When doing so
1636 it doesn't make sense to check for errors after
1637 <literal>ZOOM_connection_new</literal> is called since that
1638 operation "connecting - and init" is still incomplete and the
1639 API cannot tell the outcome (yet).
1642 <sect2 id="zoom.sru.init.behavior">
1643 <title>SRU/Solr Protocol behavior</title>
1645 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1646 Inititialize Request, so the connection phase merely establishes a
1647 TCP/IP connection with the HTTP server.
1649 <para>Most of the ZOOM connection options do not
1650 affect SRU/Solr and they are ignored. However, future versions
1651 of &yaz; might honor <literal>implementationName</literal> and
1652 put that as part of User-Agent header for HTTP requests.
1655 The <literal>charset</literal> is used in the Content-Type header
1659 Setting <literal>authentcationMode</literal> specifies how
1660 authentication parameters are encoded for HTTP. The default is
1661 "<literal>basic</literal>" where <literal>user</literal> and
1662 <literal>password</literal> are encoded by using HTTP basic
1666 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1667 user and password are encoded in the URL by parameters
1668 <literal>x-username</literal> and <literal>x-password</literal> as
1669 given by the SRU standard.
1673 <sect1 id="zoom.query">
1674 <title>Queries</title>
1676 Query objects represents queries.
1679 ZOOM_query ZOOM_query_create(void);
1681 void ZOOM_query_destroy(ZOOM_query q);
1683 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1685 int ZOOM_query_cql(ZOOM_query s, const char *str);
1687 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1689 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1690 const char *criteria);
1693 Create query objects using <function>ZOOM_query_create</function>
1694 and destroy them by calling <function>ZOOM_query_destroy</function>.
1695 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1696 notation by using the
1697 function <function>ZOOM_query_prefix</function>.
1698 The <function>ZOOM_query_cql</function> specifies a CQL
1699 query to be sent to the server/target.
1700 More query types will be added in future versions of &yaz;, such as
1701 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1702 etc. In addition to a search, a sort criteria may be set. Function
1703 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1704 it takes sort criteria using the same string notation as
1705 yaz-client's <link linkend="sortspec">sort command</link>.
1707 <para id="zoom.query.sortby2">
1708 <function>ZOOM_query_sortby2</function> is similar to
1709 <function>ZOOM_query_sortby</function> but allows a strategy for
1710 sorting. The reason for the strategy parameter is that some
1711 protocols offers multiple ways of performing sorting.
1712 For example, Z39.50 has the standard sort, which is performed after
1713 search on an existing result set.
1714 It's also possible to use CQL in Z39.50 as the query type and use
1715 CQL's SORTBY keyword. Finally, Index Data's
1716 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1718 <table id="zoom-sort-strategy" frame="top">
1719 <title>ZOOM sort strategy</title>
1721 <colspec colwidth="2*" colname="name"/>
1722 <colspec colwidth="5*" colname="description"/>
1726 <entry>Description</entry>
1731 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1734 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1737 <entry>cql</entry><entry>CQL SORTBY</entry>
1740 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1743 <entry>solr</entry><entry>Solr sort</entry>
1746 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1747 solr for Solr protocol</entry>
1753 <sect1 id="zoom.resultsets"><title>Result sets</title>
1755 The result set object is a container for records returned from
1759 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1761 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1763 void ZOOM_resultset_destroy(ZOOM_resultset r);
1766 Function <function>ZOOM_connection_search</function> creates
1767 a result set given a connection and query.
1768 Destroy a result set by calling
1769 <function>ZOOM_resultset_destroy</function>.
1770 Simple clients may using PQF only may use function
1771 <function>ZOOM_connection_search_pqf</function> in which case
1772 creating query objects is not necessary.
1775 void ZOOM_resultset_option_set(ZOOM_resultset r,
1776 const char *key, const char *val);
1778 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1780 size_t ZOOM_resultset_size(ZOOM_resultset r);
1783 Functions <function>ZOOM_resultset_options_set</function> and
1784 <function>ZOOM_resultset_get</function> sets and gets an option
1785 for a result set similar to <function>ZOOM_connection_option_get</function>
1786 and <function>ZOOM_connection_option_set</function>.
1789 The number of hits also called result-count is returned by
1790 function <function>ZOOM_resultset_size</function>.
1792 <table id="zoom.resultset.options"
1793 frame="top"><title>ZOOM Result set Options</title>
1795 <colspec colwidth="4*" colname="name"></colspec>
1796 <colspec colwidth="7*" colname="description"></colspec>
1797 <colspec colwidth="2*" colname="default"></colspec>
1800 <entry>Option</entry>
1801 <entry>Description</entry>
1802 <entry>Default</entry>
1807 start</entry><entry>Offset of first record to be
1808 retrieved from target. First record has offset 0 unlike the
1809 protocol specifications where first record has position 1.
1810 This option affects ZOOM_resultset_search and
1811 ZOOM_resultset_search_pqf and must be set before any of
1812 these functions are invoked. If a range of
1813 records must be fetched manually after search,
1814 function ZOOM_resultset_records should be used.
1815 </entry><entry>0</entry></row>
1817 count</entry><entry>Number of records to be retrieved.
1818 This option affects ZOOM_resultset_search and
1819 ZOOM_resultset_search_pqf and must be set before any of
1820 these functions are invoked.
1821 </entry><entry>0</entry></row>
1823 presentChunk</entry><entry>The number of records to be
1824 requested from the server in each chunk (present request). The
1825 value 0 means to request all the records in a single chunk.
1826 (The old <literal>step</literal>
1827 option is also supported for the benefit of old applications.)
1828 </entry><entry>0</entry></row>
1830 elementSetName</entry><entry>Element-Set name of records.
1831 Most targets should honor element set name <literal>B</literal>
1832 and <literal>F</literal> for brief and full respectively.
1833 </entry><entry>none</entry></row>
1835 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1836 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1837 </entry><entry>none</entry></row>
1839 schema</entry><entry>Schema for retrieval, such as
1840 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1841 </entry><entry>none</entry></row>
1843 setname</entry><entry>Name of Result Set (Result Set ID).
1844 If this option isn't set, the ZOOM module will automatically
1845 allocate a result set name.
1846 </entry><entry>default</entry></row>
1848 rpnCharset</entry><entry>Character set for RPN terms.
1849 If this is set, ZOOM C will assume that the ZOOM application is
1850 running UTF-8. Terms in RPN queries are then converted to the
1851 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1852 of RPN terms and no conversion is performed.
1853 </entry><entry>none</entry></row>
1858 For servers that support Search Info report, the following
1859 options may be read using <function>ZOOM_resultset_get</function>.
1860 This detailed information is read after a successful search has
1864 This information is a list of of items, where each item is
1865 information about a term or subquery. All items in the list
1867 <literal>SearchResult.</literal><replaceable>no</replaceable>
1868 where no presents the item number (0=first, 1=second).
1869 Read <literal>searchresult.size</literal> to determine the
1872 <table id="zoom.search.info.report.options"
1873 frame="top"><title>Search Info Report Options</title>
1875 <colspec colwidth="4*" colname="name"></colspec>
1876 <colspec colwidth="7*" colname="description"></colspec>
1879 <entry>Option</entry>
1880 <entry>Description</entry>
1885 <entry>searchresult.size</entry>
1887 number of search result entries. This option is-nonexistant
1888 if no entries are returned by the server.
1892 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1893 <entry>sub query ID</entry>
1896 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1897 <entry>result count for item (number of hits)</entry>
1900 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1901 <entry>subquery term</entry>
1905 searchresult.<replaceable>no</replaceable>.interpretation.term
1907 <entry>interpretation term</entry>
1911 searchresult.<replaceable>no</replaceable>.recommendation.term
1913 <entry>recommendation term</entry>
1918 <sect2 id="zoom.z3950.resultset.sort">
1919 <title>Z39.50 Result-set Sort</title>
1921 void ZOOM_resultset_sort(ZOOM_resultset r,
1922 const char *sort_type, const char *sort_spec);
1924 int ZOOM_resultset_sort1(ZOOM_resultset r,
1925 const char *sort_type, const char *sort_spec);
1928 <function>ZOOM_resultset_sort</function> and
1929 <function>ZOOM_resultset_sort1</function> both sort an existing
1930 result-set. The sort_type parameter is not use. Set it to "yaz".
1931 The sort_spec is same notation as ZOOM_query_sortby and identical
1932 to that offered by yaz-client's
1933 <link linkend="sortspec">sort command</link>.
1936 These functions only work for Z39.50. Use the more generic utility
1937 <link linkend="zoom.query.sortby2">
1938 <function>ZOOM_query_sortby2</function></link>
1939 for other protocols (and even Z39.50).
1942 <sect2 id="zoom.z3950.resultset.behavior">
1943 <title>Z39.50 Protocol behavior</title>
1945 The creation of a result set involves at least a SearchRequest
1946 - SearchResponse protocol handshake. Following that, if a sort
1947 criteria was specified as part of the query, a SortRequest -
1948 SortResponse handshake takes place. Note that it is necessary to
1949 perform sorting before any retrieval takes place, so no records will
1950 be returned from the target as part of the SearchResponse because these
1951 would be unsorted. Hence, piggyback is disabled when sort criteria
1952 are set. Following Search - and a possible sort - Retrieval takes
1953 place - as one or more Present Requests/Response pairs being
1957 The API allows for two different modes for retrieval. A high level
1958 mode which is somewhat more powerful and a low level one.
1959 The low level is enabled when searching on a Connection object
1960 for which the settings
1961 <literal>smallSetUpperBound</literal>,
1962 <literal>mediumSetPresentNumber</literal> and
1963 <literal>largeSetLowerBound</literal> are set. The low level mode
1964 thus allows you to precisely set how records are returned as part
1965 of a search response as offered by the Z39.50 protocol.
1966 Since the client may be retrieving records as part of the
1967 search response, this mode doesn't work well if sorting is used.
1970 The high-level mode allows you to fetch a range of records from
1971 the result set with a given start offset. When you use this mode
1972 the client will automatically use piggyback if that is possible
1973 with the target and perform one or more present requests as needed.
1974 Even if the target returns fewer records as part of a present response
1975 because of a record size limit, etc. the client will repeat sending
1976 present requests. As an example, if option <literal>start</literal>
1977 is 0 (default) and <literal>count</literal> is 4, and
1978 <literal>piggyback</literal> is 1 (default) and no sorting criteria
1979 is specified, then the client will attempt to retrieve the 4
1980 records as part the search response (using piggyback). On the other
1981 hand, if either <literal>start</literal> is positive or if
1982 a sorting criteria is set, or if <literal>piggyback</literal>
1983 is 0, then the client will not perform piggyback but send Present
1987 If either of the options <literal>mediumSetElementSetName</literal> and
1988 <literal>smallSetElementSetName</literal> are unset, the value
1989 of option <literal>elementSetName</literal> is used for piggyback
1990 searches. This means that for the high-level mode you only have
1991 to specify one elementSetName option rather than three.
1994 <sect2 id="zoom.sru.resultset.behavior">
1995 <title>SRU Protocol behavior</title>
1997 Current version of &yaz; does not take advantage of a result set id
1998 returned by the SRU server. Future versions might do, however.
1999 Since, the ZOOM driver does not save result set IDs any
2000 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2001 with same query but, possibly, different offsets.
2004 Option <literal>schema</literal> specifies SRU schema
2005 for retrieval. However, options <literal>elementSetName</literal> and
2006 <literal>preferredRecordSyntax</literal> are ignored.
2009 Options <literal>start</literal> and <literal>count</literal>
2010 are supported by SRU.
2011 The remaining options
2012 <literal>piggyback</literal>,
2013 <literal>smallSetUpperBound</literal>,
2014 <literal>largeSetLowerBound</literal>,
2015 <literal>mediumSetPresentNumber</literal>,
2016 <literal>mediumSetElementSetName</literal>,
2017 <literal>smallSetElementSetName</literal> are
2021 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2022 If PQF is used, however, the PQF query is transferred anyway
2023 using non-standard element <literal>pQuery</literal> in
2024 SRU SearchRetrieveRequest.
2027 Solr queries has to be done in Solr query format.
2030 Unfortunately, SRU or Solr does not define a database setting. Hence,
2031 <literal>databaseName</literal> is unsupported and ignored.
2032 However, the path part in host parameter for functions
2033 <function>ZOOM_connecton_new</function> and
2034 <function>ZOOM_connection_connect</function> acts as a
2035 database (at least for the &yaz; SRU server).
2039 <sect1 id="zoom.records">
2040 <title>Records</title>
2042 A record object is a retrieval record on the client side -
2043 created from result sets.
2046 void ZOOM_resultset_records(ZOOM_resultset r,
2048 size_t start, size_t count);
2049 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2051 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2054 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2055 const char **addinfo, const char **diagset);
2057 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2059 void ZOOM_record_destroy(ZOOM_record rec);
2062 References to temporary records are returned by functions
2063 <function>ZOOM_resultset_records</function> or
2064 <function>ZOOM_resultset_record</function>.
2067 If a persistent reference to a record is desired
2068 <function>ZOOM_record_clone</function> should be used.
2069 It returns a record reference that should be destroyed
2070 by a call to <function>ZOOM_record_destroy</function>.
2073 A single record is returned by function
2074 <function>ZOOM_resultset_record</function> that takes a
2075 position as argument. First record has position zero.
2076 If no record could be obtained <literal>NULL</literal> is returned.
2079 Error information for a record can be checked with
2080 <function>ZOOM_record_error</function> which returns non-zero
2081 (error code) if record is in error, called <emphasis>Surrogate
2082 Diagnostics</emphasis> in Z39.50.
2085 Function <function>ZOOM_resultset_records</function> retrieves
2086 a number of records from a result set. Parameter <literal>start</literal>
2087 and <literal>count</literal> specifies the range of records to
2088 be returned. Upon completion array
2089 <literal>recs[0], ..recs[count-1]</literal>
2090 holds record objects for the records. The array of records
2091 <literal>recs</literal> should be allocated prior the call
2092 <function>ZOOM_resultset_records</function>. Note that for those
2093 records that couldn't be retrieved from the target
2094 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2096 <para id="zoom.record.get">
2097 In order to extract information about a single record,
2098 <function>ZOOM_record_get</function> is provided. The
2099 function returns a pointer to certain record information. The
2100 nature (type) of the pointer depends on the parameter,
2101 <parameter>type</parameter>.
2104 The <parameter>type</parameter> is a string of the format:
2107 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>]
2110 where <replaceable>format</replaceable> specifies the format of the
2111 returned record, <replaceable>from</replaceable>
2112 specifies the character set of the record in its original form
2113 (as returned by the server), <replaceable>to</replaceable> specifies
2114 the output (returned)
2115 character set encoding.
2116 If <replaceable>to</replaceable> is omitted UTF-8 is assumed.
2117 If charset is not given, then no character set conversion takes place.
2120 <para>OPAC records may be returned in a different
2121 set from the bibliographic MARC record. If this is this the case,
2122 <replaceable>opacfrom</replaceable> should be set to the character set
2123 of the OPAC record part.
2127 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2131 The format argument controls whether record data should be XML
2132 pretty-printed (post process operation).
2133 It is enabled only if format value <replaceable>v</replaceable> is
2134 <literal>1</literal> and the record content is XML well-formed.
2137 In addition, for certain types, the length
2138 <literal>len</literal> passed will be set to the size in bytes of
2139 the returned information.
2142 The following are the supported values for <replaceable>form</replaceable>.
2144 <varlistentry><term><literal>database</literal></term>
2145 <listitem><para>Database of record is returned
2146 as a C null-terminated string. Return type
2147 <literal>const char *</literal>.
2150 <varlistentry><term><literal>syntax</literal></term>
2151 <listitem><para>The transfer syntax of the record is returned
2152 as a C null-terminated string containing the symbolic name of
2153 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2155 <literal>const char *</literal>.
2158 <varlistentry><term><literal>schema</literal></term>
2159 <listitem><para>The schema of the record is returned
2160 as a C null-terminated string. Return type is
2161 <literal>const char *</literal>.
2164 <varlistentry><term><literal>render</literal></term>
2165 <listitem><para>The record is returned in a display friendly
2166 format. Upon completion buffer is returned
2167 (type <literal>const char *</literal>) and length is stored in
2168 <literal>*len</literal>.
2171 <varlistentry><term><literal>raw</literal></term>
2172 <listitem><para>The record is returned in the internal
2173 YAZ specific format. For GRS-1, Explain, and others, the
2174 raw data is returned as type
2175 <literal>Z_External *</literal> which is just the type for
2176 the member <literal>retrievalRecord</literal> in
2177 type <literal>NamePlusRecord</literal>.
2178 For SUTRS and octet aligned record (including all MARCs) the
2179 octet buffer is returned and the length of the buffer.
2182 <varlistentry><term><literal>xml</literal></term>
2183 <listitem><para>The record is returned in XML if possible.
2184 SRU, Solr and Z39.50 records with transfer syntax XML are
2185 returned verbatim. MARC records are returned in
2186 <ulink url="&url.marcxml;">
2189 (converted from ISO2709 to MARCXML by YAZ).
2190 OPAC records are also converted to XML and the
2191 bibliographic record is converted to MARCXML (when possible).
2192 GRS-1 records are not supported for this form.
2193 Upon completion, the XML buffer is returned
2194 (type <literal>const char *</literal>) and length is stored in
2195 <literal>*len</literal>.
2198 <varlistentry><term><literal>opac</literal></term>
2199 <listitem><para>OPAC information for record is returned in XML
2200 if an OPAC record is present at the position given. If no
2201 OPAC record is present, a NULL pointer is returned.
2204 <varlistentry><term><literal>txml</literal></term>
2205 <listitem><para>The record is returned in TurboMARC if possible.
2206 SRU and Z39.50 records with transfer syntax XML are
2207 returned verbatim. MARC records are returned in
2208 <link linkend="tools.turbomarc">
2211 (converted from ISO2709 to TurboMARC by YAZ).
2212 Upon completion, the XML buffer is returned
2213 (type <literal>const char *</literal>) and length is stored in
2214 <literal>*len</literal>.
2217 <varlistentry><term><literal>json</literal></term>
2218 <listitem><para>Like xml, but MARC records are converted to
2219 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2227 <ulink url="&url.marc21;">MARC21</ulink>
2229 <ulink url="&url.marc8;">MARC-8</ulink>
2230 character set encoding.
2231 An application that wishes to display in Latin-1 would use
2233 render; charset=marc8,iso-8859-1
2236 <sect2 id="zoom.z3950.record.behavior">
2237 <title>Z39.50 Protocol behavior</title>
2239 The functions <function>ZOOM_resultset_record</function> and
2240 <function>ZOOM_resultset_records</function> inspects the client-side
2241 record cache. Records not found in cache are fetched using
2243 The functions may block (and perform network I/O) - even though option
2244 <literal>async</literal> is 1, because they return records objects.
2245 (and there's no way to return records objects without retrieving them!).
2248 There is a trick, however, in the usage of function
2249 <function>ZOOM_resultset_records</function> that allows for
2250 delayed retrieval (and makes it non-blocking). By using
2251 a null pointer for <parameter>recs</parameter> you're indicating
2252 you're not interested in getting records objects
2253 <emphasis>now</emphasis>.
2256 <sect2 id="zoom.sru.record.behavior">
2257 <title>SRU/Solr Protocol behavior</title>
2259 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2260 as if they where Z39.50 records with transfer syntax XML and
2261 no element set name or database name.
2265 <sect1 id="zoom.facets"><title>Facets</title>
2267 Facet operations is not part of the official ZOOM specification, but
2268 is an Index Data extension for YAZ-based Z39.50 targets,
2269 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2271 Facets may be requestd by the
2272 <link linkend="zoom.facets.option">facets</link> option before a
2274 For inspection of the returned facets, the following functions are
2278 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2280 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2281 const char *facet_name);
2283 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2286 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2288 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2290 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2292 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2293 size_t idx, int *freq);
2296 References to temporary structures are returned by all functions.
2297 They are only valid as long the Result set is valid.
2298 <function>ZOOM_resultset_get_facet_field</function> or
2299 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2300 <function>ZOOM_resultset_facets</function>.
2301 <function>ZOOM_facet_field_name</function>.
2302 <function>ZOOM_facet_field_get_term</function>.
2304 <para id="zoom.resultset.get_facet_field">
2305 A single Facet field is returned by function
2306 <function>ZOOM_resultset_get_facet_field</function> or
2307 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2308 a result set and facet name or positive index respectively. First
2309 facet has position zero. If no facet could be obtained (invalid name
2310 or index out of bounds) <literal>NULL</literal> is returned.
2312 <para id="zoom.resultset.facets">
2313 An array of facets field can be returned by
2314 <function>ZOOM_resultset_facets</function>. The length of the array is
2315 given by <function>ZOOM_resultset_facets_size</function>. The array is
2316 zero-based and last entry will be at
2317 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2319 <para id="zoom.resultset.facets_names">
2320 It is possible to interate over facets by name, by calling
2321 <function>ZOOM_resultset_facets_names</function>.
2322 This will return an const array of char * where each string can be used
2323 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2326 Function <function>ZOOM_facet_field_name</function> gets the request
2327 facet name from a returned facet field.
2330 Function <function>ZOOM_facet_field_get_term</function> returns the
2331 idx'th term and term count for a facet field.
2332 Idx must between 0 and
2333 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2334 returned reference will be <literal>NULL</literal>. On a valid idx, the
2335 value of the freq reference will be the term count.
2336 The <literal>freq</literal> parameter must be valid pointer to integer.
2339 <sect1 id="zoom.scan"><title>Scan</title>
2341 This section describes an interface for Scan. Scan is not an
2342 official part of the ZOOM model yet. The result of a scan operation
2343 is the <literal>ZOOM_scanset</literal> which is a set of terms
2344 returned by a target.
2348 The Scan interface is supported for both Z39.50, SRU and Solr.
2352 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2353 const char *startpqf);
2355 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2358 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2360 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2361 size_t *occ, size_t *len);
2363 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2364 size_t *occ, size_t *len);
2366 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2368 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2371 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2375 The scan set is created by function
2376 <function>ZOOM_connection_scan</function> which performs a scan
2377 operation on the connection using the specified
2378 <parameter>startpqf</parameter>.
2379 If the operation was successful, the size of the scan set can be
2380 retrieved by a call to <function>ZOOM_scanset_size</function>.
2381 Like result sets, the items are numbered 0,..size-1.
2382 To obtain information about a particular scan term, call function
2383 <function>ZOOM_scanset_term</function>. This function takes
2384 a scan set offset <literal>pos</literal> and returns a pointer
2385 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2387 If present, the <literal>occ</literal> and <literal>len</literal>
2388 are set to the number of occurrences and the length
2389 of the actual term respectively.
2390 <function>ZOOM_scanset_display_term</function> is similar to
2391 <function>ZOOM_scanset_term</function> except that it returns
2392 the <emphasis>display term</emphasis> rather than the raw term.
2393 In a few cases, the term is different from display term. Always
2394 use the display term for display and the raw term for subsequent
2395 scan operations (to get more terms, next scan result, etc).
2398 A scan set may be freed by a call to function
2399 <function>ZOOM_scanset_destroy</function>.
2400 Functions <function>ZOOM_scanset_option_get</function> and
2401 <function>ZOOM_scanset_option_set</function> retrieves and sets
2402 an option respectively.
2405 The <parameter>startpqf</parameter> is a subset of PQF, namely
2406 the Attributes+Term part. Multiple <literal>@attr</literal> can
2407 be used. For example to scan in title (complete) phrases:
2409 @attr 1=4 @attr 6=2 "science o"
2413 The <function>ZOOM_connecton_scan1</function> is a newer and
2414 more generic alternative to <function>ZOOM_connection_scan</function>
2415 which allows to use both CQL and PQF for Scan.
2417 <table frame="top" id="zoom.scanset.options">
2418 <title>ZOOM Scan Set Options</title>
2420 <colspec colwidth="4*" colname="name"></colspec>
2421 <colspec colwidth="7*" colname="description"></colspec>
2422 <colspec colwidth="2*" colname="default"></colspec>
2425 <entry>Option</entry>
2426 <entry>Description</entry>
2427 <entry>Default</entry>
2432 number</entry><entry>Number of Scan Terms requested in next scan.
2433 After scan it holds the actual number of terms returned.
2434 </entry><entry>20</entry></row>
2436 position</entry><entry>Preferred Position of term in response
2437 in next scan; actual position after completion of scan.
2438 </entry><entry>1</entry></row>
2440 stepSize</entry><entry>Step Size
2441 </entry><entry>0</entry></row>
2443 scanStatus</entry><entry>An integer indicating the Scan Status
2445 </entry><entry>0</entry></row>
2447 rpnCharset</entry><entry>Character set for RPN terms.
2448 If this is set, ZOOM C will assume that the ZOOM application is
2449 running UTF-8. Terms in RPN queries are then converted to the
2450 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2451 of RPN terms and no conversion is performed.
2452 </entry><entry>none</entry></row>
2457 <sect1 id="zoom.extendedservices">
2458 <title>Extended Services</title>
2460 ZOOM offers an interface to a subset of the Z39.50 extended services
2461 as well as a few privately defined ones:
2466 Z39.50 Item Order (ILL).
2467 See <xref linkend="zoom.item.order"/>.
2472 Record Update. This allows a client to insert, modify or delete
2474 See <xref linkend="zoom.record.update"/>.
2479 Database Create. This a non-standard feature. Allows a client
2480 to create a database.
2481 See <xref linkend="zoom.database.create"/>.
2486 Database Drop. This a non-standard feature. Allows a client
2487 to delete/drop a database.
2488 See <xref linkend="zoom.database.drop"/>.
2493 Commit operation. This a non-standard feature. Allows a client
2494 to commit operations.
2495 See <xref linkend="zoom.commit"/>.
2498 <!-- all the ILL PDU options should go here too -->
2501 To create an extended service operation a <literal>ZOOM_package</literal>
2502 must be created. The operation is a five step operation. The
2503 package is created, package is configured by means of options,
2504 the package is send, result is inspected (by means of options),
2505 the package is destroyed.
2508 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2509 ZOOM_options options);
2511 const char *ZOOM_package_option_get(ZOOM_package p,
2513 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2515 void ZOOM_package_send(ZOOM_package p, const char *type);
2517 void ZOOM_package_destroy(ZOOM_package p);
2520 The <function>ZOOM_connection_package</function> creates a
2521 package for the connection given using the options specified.
2524 Functions <function>ZOOM_package_option_get</function> and
2525 <function>ZOOM_package_option_set</function> gets and sets
2529 <function>ZOOM_package_send</function> sends
2530 the package the via connection specified in
2531 <function>ZOOM_connection_package</function>.
2532 The <parameter>type</parameter> specifies the actual extended service
2533 package type to be sent.
2535 <table frame="top" id="zoom.extendedservices.options">
2536 <title>Extended Service Common Options</title>
2538 <colspec colwidth="4*" colname="name"></colspec>
2539 <colspec colwidth="7*" colname="description"></colspec>
2540 <colspec colwidth="3*" colname="default"></colspec>
2543 <entry>Option</entry>
2544 <entry>Description</entry>
2545 <entry>Default</entry>
2550 <entry>package-name</entry>
2551 <entry>Extended Service Request package name. Must be specified
2552 as part of a request</entry>
2556 <entry>user-id</entry>
2557 <entry>User ID of Extended Service Package. Is a request option</entry>
2561 <entry>function</entry>
2563 Function of package - one of <literal>create</literal>,
2564 <literal>delete</literal>, <literal>modify</literal>. Is
2567 <entry><literal>create</literal></entry>
2570 <entry>waitAction</entry>
2572 Wait action for package. Possible values:
2573 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2574 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2576 <entry><literal>waitIfPossible</literal></entry>
2579 <entry>targetReference</entry>
2581 Target Reference. This is part of the response as returned
2582 by the server. Read it after a successful operation.
2584 <entry><literal>none</literal></entry>
2589 <sect2 id="zoom.item.order">
2590 <title>Item Order</title>
2592 For Item Order, type must be set to <literal>itemorder</literal> in
2593 <function>ZOOM_package_send</function>.
2596 <table frame="top" id="zoom.item.order.options">
2597 <title>Item Order Options</title>
2599 <colspec colwidth="4*" colname="name"></colspec>
2600 <colspec colwidth="7*" colname="description"></colspec>
2601 <colspec colwidth="3*" colname="default"></colspec>
2604 <entry>Option</entry>
2605 <entry>Description</entry>
2606 <entry>Default</entry>
2611 <entry>contact-name</entry>
2612 <entry>ILL contact name</entry>
2616 <entry>contact-phone</entry>
2617 <entry>ILL contact phone</entry>
2621 <entry>contact-email</entry>
2622 <entry>ILL contact email</entry>
2626 <entry>itemorder-item</entry>
2627 <entry>Position for item (record) requested. An integer</entry>
2634 <sect2 id="zoom.record.update">
2635 <title>Record Update</title>
2637 For Record Update, type must be set to <literal>update</literal> in
2638 <function>ZOOM_package_send</function>.
2640 <table frame="top" id="zoom.record.update.options">
2641 <title>Record Update Options</title>
2643 <colspec colwidth="4*" colname="name"></colspec>
2644 <colspec colwidth="7*" colname="description"></colspec>
2645 <colspec colwidth="3*" colname="default"></colspec>
2648 <entry>Option</entry>
2649 <entry>Description</entry>
2650 <entry>Default</entry>
2655 <entry>action</entry>
2657 The update action. One of
2658 <literal>specialUpdate</literal>,
2659 <literal>recordInsert</literal>,
2660 <literal>recordReplace</literal>,
2661 <literal>recordDelete</literal>,
2662 <literal>elementUpdate</literal>.
2664 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2667 <entry>recordIdOpaque</entry>
2668 <entry>Opaque Record ID</entry>
2672 <entry>recordIdNumber</entry>
2673 <entry>Record ID number</entry>
2677 <entry>record</entry>
2678 <entry>The record itself</entry>
2682 <entry>recordOpaque</entry>
2683 <entry>Specifies an opaque record which is
2684 encoded as an ASN.1 ANY type with the OID as tiven by option
2685 <literal>syntax</literal> (see below).
2686 Option <literal>recordOpaque</literal> is an alternative
2687 to record - and <literal>record</literal> option (above) is
2688 ignored if recordOpaque is set. This option is only available in
2689 YAZ 3.0.35 and later and is meant to facilitate Updates with
2695 <entry>syntax</entry>
2696 <entry>The record syntax (transfer syntax). Is a string that
2697 is a known record syntax.
2699 <entry>no syntax</entry>
2702 <entry>databaseName</entry>
2703 <entry>Database from connection object</entry>
2704 <entry>Default</entry>
2707 <entry>correlationInfo.note</entry>
2708 <entry>Correlation Info Note (string)</entry>
2712 <entry>correlationInfo.id</entry>
2713 <entry>Correlation Info ID (integer)</entry>
2717 <entry>elementSetName</entry>
2718 <entry>Element Set for Record</entry>
2722 <entry>updateVersion</entry>
2723 <entry>Record Update version which holds one of the values
2724 1, 2 or 3. Each version has a distinct OID:
2726 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2728 (second version) and
2729 1.2.840.10003.9.5.1.1
2730 (<ulink url="&url.z39.50.extupdate3;">third and
2731 newest version</ulink>).
2741 <sect2 id="zoom.database.create"><title>Database Create</title>
2743 For Database Create, type must be set to <literal>create</literal> in
2744 <function>ZOOM_package_send</function>.
2747 <table frame="top" id="zoom.database.create.options">
2748 <title>Database Create Options</title>
2750 <colspec colwidth="4*" colname="name"></colspec>
2751 <colspec colwidth="7*" colname="description"></colspec>
2752 <colspec colwidth="3*" colname="default"></colspec>
2755 <entry>Option</entry>
2756 <entry>Description</entry>
2757 <entry>Default</entry>
2762 <entry>databaseName</entry>
2763 <entry>Database from connection object</entry>
2764 <entry>Default</entry>
2770 <sect2 id="zoom.database.drop">
2771 <title>Database Drop</title>
2773 For Database Drop, type must be set to <literal>drop</literal> in
2774 <function>ZOOM_package_send</function>.
2776 <table frame="top" id="zoom.database.drop.options">
2777 <title>Database Drop Options</title>
2779 <colspec colwidth="4*" colname="name"></colspec>
2780 <colspec colwidth="7*" colname="description"></colspec>
2781 <colspec colwidth="3*" colname="default"></colspec>
2784 <entry>Option</entry>
2785 <entry>Description</entry>
2786 <entry>Default</entry>
2791 <entry>databaseName</entry>
2792 <entry>Database from connection object</entry>
2793 <entry>Default</entry>
2799 <sect2 id="zoom.commit">
2800 <title>Commit Operation</title>
2802 For Commit, type must be set to <literal>commit</literal> in
2803 <function>ZOOM_package_send</function>.
2806 <sect2 id="zoom.extended.services.behavior">
2807 <title>Protocol behavior</title>
2809 All the extended services are Z39.50-only.
2813 The database create, drop and commit services are privately defined
2815 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2821 <sect1 id="zoom.options">
2822 <title>Options</title>
2824 Most &zoom; objects provide a way to specify options to change behavior.
2825 From an implementation point of view a set of options is just like
2826 an associative array / hash.
2829 ZOOM_options ZOOM_options_create(void);
2831 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
2833 void ZOOM_options_destroy(ZOOM_options opt);
2836 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
2838 void ZOOM_options_set(ZOOM_options opt, const char *name,
2842 typedef const char *(*ZOOM_options_callback)
2843 (void *handle, const char *name);
2845 ZOOM_options_callback
2846 ZOOM_options_set_callback(ZOOM_options opt,
2847 ZOOM_options_callback c,
2851 <sect1 id="zoom.queryconversions">
2852 <title>Query conversions</title>
2854 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
2855 ZOOM_connection conn);
2857 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
2859 int *ccl_error, const char **error_string,
2863 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
2864 client-side, into RPN which may be passed to the server.
2865 This is useful for server's that don't themselves
2866 support CQL, for which <function>ZOOM_query_cql</function> is useless.
2867 `conn' is used only as a place to stash diagnostics if compilation
2868 fails; if this information is not needed, a null pointer may be used.
2869 The CQL conversion is driven by option <literal>cqlfile</literal> from
2870 connection conn. This specifies a conversion file (eg pqf.properties)
2871 which <emphasis>must</emphasis> be present.
2874 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
2875 client-side, into RPN which may be passed to the server.
2876 The conversion is driven by the specification given by
2877 <literal>config</literal>. Upon completion 0 is returned on success; -1
2878 is returned on on failure. Om failure <literal>error_string</literal> and
2879 <literal>error_pos</literal> holds error message and position of
2880 first error in original CCL string.
2883 <sect1 id="zoom.events"><title>Events</title>
2885 If you're developing non-blocking applications, you have to deal
2889 int ZOOM_event(int no, ZOOM_connection *cs);
2892 The <function>ZOOM_event</function> executes pending events for
2893 a number of connections. Supply the number of connections in
2894 <literal>no</literal> and an array of connections in
2895 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
2896 A pending event could be a sending a search, receiving a response,
2898 When an event has occurred for one of the connections, this function
2899 returns a positive integer <literal>n</literal> denoting that an event
2900 occurred for connection <literal>cs[n-1]</literal>.
2901 When no events are pending for the connections, a value of zero is
2903 To ensure that all outstanding requests are performed call this function
2904 repeatedly until zero is returned.
2907 If <function>ZOOM_event</function> returns and returns non-zero, the
2908 last event that occurred can be expected.
2911 int ZOOM_connection_last_event(ZOOM_connection cs);
2914 <function>ZOOM_connection_last_event</function> returns an event type
2915 (integer) for the last event.
2918 <table frame="top" id="zoom.event.ids">
2919 <title>ZOOM Event IDs</title>
2921 <colspec colwidth="4*" colname="name"></colspec>
2922 <colspec colwidth="7*" colname="description"></colspec>
2925 <entry>Event</entry>
2926 <entry>Description</entry>
2931 <entry>ZOOM_EVENT_NONE</entry>
2932 <entry>No event has occurred</entry>
2935 <entry>ZOOM_EVENT_CONNECT</entry>
2936 <entry>TCP/IP connect has initiated</entry>
2939 <entry>ZOOM_EVENT_SEND_DATA</entry>
2940 <entry>Data has been transmitted (sending)</entry>
2943 <entry>ZOOM_EVENT_RECV_DATA</entry>
2944 <entry>Data has been received)</entry>
2947 <entry>ZOOM_EVENT_TIMEOUT</entry>
2948 <entry>Timeout</entry>
2951 <entry>ZOOM_EVENT_UNKNOWN</entry>
2952 <entry>Unknown event</entry>
2955 <entry>ZOOM_EVENT_SEND_APDU</entry>
2956 <entry>An APDU has been transmitted (sending)</entry>
2959 <entry>ZOOM_EVENT_RECV_APDU</entry>
2960 <entry>An APDU has been received</entry>
2963 <entry>ZOOM_EVENT_RECV_RECORD</entry>
2964 <entry>A result-set record has been received</entry>
2967 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
2968 <entry>A search result been received</entry>
2975 <chapter id="server">
2976 <title>Generic server</title>
2977 <sect1 id="server.introduction"><title>Introduction</title>
2979 If you aren't into documentation, a good way to learn how the
2980 back end interface works is to look at the <filename>backend.h</filename>
2981 file. Then, look at the small dummy-server in
2982 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
2983 file also makes a good reference, once you've chewed your way through
2984 the prose of this file.
2987 If you have a database system that you would like to make available by
2988 means of Z39.50 or SRU, &yaz; basically offers your two options. You
2989 can use the APIs provided by the &asn;, &odr;, and &comstack;
2991 create and decode PDUs, and exchange them with a client.
2992 Using this low-level interface gives you access to all fields and
2993 options of the protocol, and you can construct your server as close
2994 to your existing database as you like.
2995 It is also a fairly involved process, requiring
2996 you to set up an event-handling mechanism, protocol state machine,
2997 etc. To simplify server implementation, we have implemented a compact
2998 and simple, but reasonably full-functioned server-frontend that will
2999 handle most of the protocol mechanics, while leaving you to
3000 concentrate on your database interface.
3004 The backend interface was designed in anticipation of a specific
3005 integration task, while still attempting to achieve some degree of
3006 generality. We realize fully that there are points where the
3007 interface can be improved significantly. If you have specific
3008 functions or parameters that you think could be useful, send us a
3009 mail (or better, sign on to the mailing list referred to in the
3010 top-level README file). We will try to fit good suggestions into future
3011 releases, to the extent that it can be done without requiring
3012 too many structural changes in existing applications.
3017 The &yaz; server does not support XCQL.
3021 <sect1 id="server.frontend">
3022 <title>The Database Frontend</title>
3024 We refer to this software as a generic database frontend. Your
3025 database system is the <emphasis>backend database</emphasis>, and the
3026 interface between the two is called the <emphasis>backend API</emphasis>.
3027 The backend API consists of a small number of function handlers and
3028 structure definitions. You are required to provide the
3029 <function>main()</function> routine for the server (which can be
3030 quite simple), as well as a set of handlers to match each of the
3032 The interface functions that you write can use any mechanism you like
3033 to communicate with your database system: You might link the whole
3034 thing together with your database application and access it by
3035 function calls; you might use IPC to talk to a database server
3036 somewhere; or you might link with third-party software that handles
3037 the communication for you (like a commercial database client library).
3038 At any rate, the handlers will perform the tasks of:
3051 Scanning the database index (optional - if you wish to implement SCAN).
3054 Extended Services (optional).
3057 Result-Set Delete (optional).
3060 Result-Set Sort (optional).
3063 Return Explain for SRU (optional).
3067 (more functions will be added in time to support as much of
3068 Z39.50-1995 as possible).
3071 <sect1 id="server.backend">
3072 <title>The Backend API</title>
3074 The header file that you need to use the interface are in the
3075 <filename>include/yaz</filename> directory. It's called
3076 <filename>backend.h</filename>. It will include other files from
3077 the <filename>include/yaz</filename> directory, so you'll
3078 probably want to use the -I option of your compiler to tell it
3079 where to find the files. When you run
3080 <literal>make</literal> in the top-level &yaz; directory,
3081 everything you need to create your server is to link with the
3082 <filename>lib/libyaz.la</filename> library.
3085 <sect1 id="server.main">
3086 <title>Your main() Routine</title>
3088 As mentioned, your <function>main()</function> routine can be quite brief.
3089 If you want to initialize global parameters, or read global configuration
3090 tables, this is the place to do it. At the end of the routine, you should
3094 int statserv_main(int argc, char **argv,
3095 bend_initresult *(*bend_init)(bend_initrequest *r),
3096 void (*bend_close)(void *handle));
3099 The third and fourth arguments are pointers to handlers. Handler
3100 <function>bend_init</function> is called whenever the server receives
3101 an Initialize Request, so it serves as a Z39.50 session initializer. The
3102 <function>bend_close</function> handler is called when the session is
3106 <function>statserv_main</function> will establish listening sockets
3107 according to the parameters given. When connection requests are received,
3108 the event handler will typically <function>fork()</function> and
3109 create a sub-process to handle a new connection.
3110 Alternatively the server may be setup to create threads for each
3112 If you do use global variables and forking, you should be aware, then,
3113 that these cannot be shared between associations, unless you explicitly
3114 disable forking by command line parameters.
3117 The server provides a mechanism for controlling some of its behavior
3118 without using command-line options. The function
3121 statserv_options_block *statserv_getcontrol(void);
3124 will return a pointer to a <literal>struct statserv_options_block</literal>
3125 describing the current default settings of the server. The structure
3126 contains these elements:
3129 <term><literal>int dynamic</literal></term>
3131 A boolean value, which determines whether the server
3132 will fork on each incoming request (TRUE), or not (FALSE). Default is
3133 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3138 <term><literal>int threads</literal></term>
3140 A boolean value, which determines whether the server
3141 will create a thread on each incoming request (TRUE), or not (FALSE).
3142 Default is FALSE. This flag is only read by UNIX-based servers
3143 that offer POSIX Threads support.
3144 WIN32-based servers always operate in threaded mode.
3148 <term><literal>int inetd</literal></term>
3150 A boolean value, which determines whether the server
3151 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3155 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3156 <listitem><para>File for diagnostic output ("": stderr).
3160 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3162 Name of file for logging incoming and outgoing APDUs
3163 ("": don't log APDUs, "-":
3164 <literal>stderr</literal>).
3168 <term><literal>char default_listen[1024]</literal></term>
3169 <listitem><para>Same form as the command-line specification of
3170 listener address. "": no default listener address.
3171 Default is to listen at "tcp:@:9999". You can only
3172 specify one default listener address in this fashion.
3176 <term><literal>enum oid_proto default_proto;</literal></term>
3177 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3178 <literal>PROTO_SR</literal>.
3179 Default is <literal>PROTO_Z39_50</literal>.
3183 <term><literal>int idle_timeout;</literal></term>
3184 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3185 no (infinite) timeout. Default is 15 minutes.
3189 <term><literal>int maxrecordsize;</literal></term>
3190 <listitem><para>Maximum permissible record (message) size. Default
3191 is 64 MB. This amount of memory will only be allocated if a
3192 client requests a very large amount of records in one operation
3194 Set it to a lower number if you are worried about resource
3195 consumption on your host system.
3199 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3200 <listitem><para>Passed to the backend when a new connection is received.
3204 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3205 <listitem><para>Set user id to the user specified, after binding
3206 the listener addresses.
3211 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3213 <listitem><para>Pointer to function which is called after the
3214 command line options have been parsed - but before the server
3216 For forked UNIX servers this handler is called in the mother
3217 process; for threaded servers this handler is called in the
3219 The default value of this pointer is NULL in which case it
3220 isn't invoked by the frontend server.
3221 When the server operates as an NT service this handler is called
3222 whenever the service is started.
3227 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3229 <listitem><para>Pointer to function which is called whenever the server
3230 has stopped listening for incoming connections. This function pointer
3231 has a default value of NULL in which case it isn't called.
3232 When the server operates as an NT service this handler is called
3233 whenever the service is stopped.
3237 <term><literal>void *handle</literal></term>
3238 <listitem><para>User defined pointer (default value NULL).
3239 This is a per-server handle that can be used to specify "user-data".
3240 Do not confuse this with the session-handle as returned by bend_init.
3246 The pointer returned by <literal>statserv_getcontrol</literal> points to
3247 a static area. You are allowed to change the contents of the structure,
3248 but the changes will not take effect before you call
3251 void statserv_setcontrol(statserv_options_block *block);
3255 that you should generally update this structure before calling
3256 <function>statserv_main()</function>.
3260 <sect1 id="server.backendfunctions">
3261 <title>The Backend Functions</title>
3263 For each service of the protocol, the backend interface declares one or
3264 two functions. You are required to provide implementations of the
3265 functions representing the services that you wish to implement.
3267 <sect2 id="server.init">
3270 bend_initresult (*bend_init)(bend_initrequest *r);
3273 This handler is called once for each new connection request, after
3274 a new process/thread has been created, and an Initialize Request has
3275 been received from the client. The pointer to the
3276 <function>bend_init</function> handler is passed in the call to
3277 <function>statserv_start</function>.
3280 This handler is also called when operating in SRU mode - when
3281 a connection has been made (even though SRU does not offer
3285 Unlike previous versions of YAZ, the <function>bend_init</function> also
3286 serves as a handler that defines the Z39.50 services that the backend
3287 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3288 including search - and fetch must be specified here in this handler.
3291 The request - and result structures are defined as
3294 typedef struct bend_initrequest
3296 /** \brief user/name/password to be read */
3297 Z_IdAuthentication *auth;
3298 /** \brief encoding stream (for results) */
3300 /** \brief printing stream */
3302 /** \brief decoding stream (use stream for results) */
3304 /** \brief reference ID */
3305 Z_ReferenceId *referenceId;
3306 /** \brief peer address of client */
3309 /** \brief character set and language negotiation
3311 see include/yaz/z-charneg.h
3313 Z_CharSetandLanguageNegotiation *charneg_request;
3315 /** \brief character negotiation response */
3316 Z_External *charneg_response;
3318 /** \brief character set (encoding) for query terms
3320 This is NULL by default. It should be set to the native character
3321 set that the backend assumes for query terms */
3322 char *query_charset;
3324 /** \brief whehter query_charset also applies to recors
3326 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3327 character set as queries. If in doubt, use 0 (No).
3329 int records_in_same_charset;
3331 char *implementation_id;
3332 char *implementation_name;
3333 char *implementation_version;
3335 /** \brief Z39.50 sort handler */
3336 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3337 /** \brief SRU/Z39.50 search handler */
3338 int (*bend_search)(void *handle, bend_search_rr *rr);
3339 /** \brief SRU/Z39.50 fetch handler */
3340 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3341 /** \brief SRU/Z39.50 present handler */
3342 int (*bend_present)(void *handle, bend_present_rr *rr);
3343 /** \brief Z39.50 extended services handler */
3344 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3345 /** \brief Z39.50 delete result set handler */
3346 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3347 /** \brief Z39.50 scan handler */
3348 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3349 /** \brief Z39.50 segment facility handler */
3350 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3351 /** \brief SRU explain handler */
3352 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3353 /** \brief SRU scan handler */
3354 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3355 /** \brief SRU record update handler */
3356 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3358 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3359 int named_result_sets;
3362 typedef struct bend_initresult
3364 int errcode; /* 0==OK */
3365 char *errstring; /* system error string or NULL */
3366 void *handle; /* private handle to the backend module */
3370 In general, the server frontend expects that the
3371 <literal>bend_*result</literal> pointer that you return is valid at
3372 least until the next call to a <literal>bend_* function</literal>.
3373 This applies to all of the functions described herein. The parameter
3374 structure passed to you in the call belongs to the server frontend, and
3375 you should not make assumptions about its contents after the current
3376 function call has completed. In other words, if you want to retain any
3377 of the contents of a request structure, you should copy them.
3380 The <literal>errcode</literal> should be zero if the initialization of
3381 the backend went well. Any other value will be interpreted as an error.
3382 The <literal>errstring</literal> isn't used in the current version, but
3383 one option would be to stick it in the initResponse as a VisibleString.
3384 The <literal>handle</literal> is the most important parameter. It should
3385 be set to some value that uniquely identifies the current session to
3386 the backend implementation. It is used by the frontend server in any
3387 future calls to a backend function.
3388 The typical use is to set it to point to a dynamically allocated state
3389 structure that is private to your backend module.
3392 The <literal>auth</literal> member holds the authentication information
3393 part of the Z39.50 Initialize Request. Interpret this if your serves
3394 requires authentication.
3397 The members <literal>peer_name</literal>,
3398 <literal>implementation_id</literal>,
3399 <literal>implementation_name</literal> and
3400 <literal>implementation_version</literal> holds
3401 DNS of client, ID of implementor, name
3402 of client (Z39.50) implementation - and version.
3405 The <literal>bend_</literal> - members are set to NULL when
3406 <function>bend_init</function> is called. Modify the pointers by
3407 setting them to point to backend functions.
3410 <sect2 id="server.search.retrieve">
3411 <title>Search and Retrieve</title>
3413 We now describe the handlers that are required to support search -
3414 and retrieve. You must support two functions - one for search - and one
3415 for fetch (retrieval of one record). If desirable you can provide a
3416 third handler which is called when a present request is received which
3417 allows you to optimize retrieval of multiple-records.
3420 int (*bend_search) (void *handle, bend_search_rr *rr);
3423 char *setname; /* name to give to this set */
3424 int replace_set; /* replace set, if it already exists */
3425 int num_bases; /* number of databases in list */
3426 char **basenames; /* databases to search */
3427 Z_ReferenceId *referenceId;/* reference ID */
3428 Z_Query *query; /* query structure */
3429 ODR stream; /* encode stream */
3430 ODR decode; /* decode stream */
3431 ODR print; /* print stream */
3433 bend_request request;
3434 bend_association association;
3436 int hits; /* number of hits */
3437 int errcode; /* 0==OK */
3438 char *errstring; /* system error string or NULL */
3439 Z_OtherInformation *search_info; /* additional search info */
3440 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3441 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3442 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3443 int estimated_hit_count; /* if hit count is estimated */
3444 int partial_resultset; /* if result set is partial */
3448 The <function>bend_search</function> handler is a fairly close
3449 approximation of a protocol Z39.50 Search Request - and Response PDUs
3450 The <literal>setname</literal> is the resultSetName from the protocol.
3451 You are required to establish a mapping between the set name and whatever
3452 your backend database likes to use.
3453 Similarly, the <literal>replace_set</literal> is a boolean value
3454 corresponding to the resultSetIndicator field in the protocol.
3455 <literal>num_bases/basenames</literal> is a length of/array of character
3456 pointers to the database names provided by the client.
3457 The <literal>query</literal> is the full query structure as defined in
3458 the protocol ASN.1 specification.
3459 It can be either of the possible query types, and it's up to you to
3460 determine if you can handle the provided query type.
3461 Rather than reproduce the C interface here, we'll refer you to the
3462 structure definitions in the file
3463 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3464 attributeSetId OID of the RPN query, you can either match it against
3465 your own internal tables, or you can use the <link linkend="tools.oid">
3469 The structure contains a number of hits, and an
3470 <literal>errcode/errstring</literal> pair. If an error occurs
3471 during the search, or if you're unhappy with the request, you should
3472 set the errcode to a value from the BIB-1 diagnostic set. The value
3473 will then be returned to the user in a nonsurrogate diagnostic record
3474 in the response. The <literal>errstring</literal>, if provided, will
3475 go in the addinfo field. Look at the protocol definition for the
3476 defined error codes, and the suggested uses of the addinfo field.
3479 The <function>bend_search</function> handler is also called when
3480 the frontend server receives a SRU SearchRetrieveRequest.
3481 For SRU, a CQL query is usually provided by the client.
3482 The CQL query is available as part of <literal>Z_Query</literal>
3483 structure (note that CQL is now part of Z39.50 via an external).
3484 To support CQL in existing implementations that only do Type-1,
3485 we refer to the CQL-to-PQF tool described
3486 <link linkend="cql.to.pqf">here</link>.
3489 To maintain backwards compatibility, the frontend server
3490 of yaz always assume that error codes are BIB-1 diagnostics.
3491 For SRU operation, a Bib-1 diagnostic code is mapped to
3495 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3497 typedef struct bend_fetch_rr {
3498 char *setname; /* set name */
3499 int number; /* record number */
3500 Z_ReferenceId *referenceId;/* reference ID */
3501 Odr_oid *request_format; /* format, transfer syntax (OID) */
3502 Z_RecordComposition *comp; /* Formatting instructions */
3503 ODR stream; /* encoding stream - memory source if req */
3504 ODR print; /* printing stream */
3506 char *basename; /* name of database that provided record */
3507 int len; /* length of record or -1 if structured */
3508 char *record; /* record */
3509 int last_in_set; /* is it? */
3510 Odr_oid *output_format; /* response format/syntax (OID) */
3511 int errcode; /* 0==success */
3512 char *errstring; /* system error string or NULL */
3513 int surrogate_flag; /* surrogate diagnostic */
3514 char *schema; /* string record schema input/output */
3518 The frontend server calls the <function>bend_fetch</function> handler
3519 when it needs database records to fulfill a Z39.50 Search Request, a
3520 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3521 The <literal>setname</literal> is simply the name of the result set
3522 that holds the reference to the desired record.
3523 The <literal>number</literal> is the offset into the set (with 1
3524 being the first record in the set). The <literal>format</literal> field
3525 is the record format requested by the client (See
3526 <xref linkend="tools.oid"/>).
3527 A value of NULL for <literal>format</literal> indicates that the
3528 client did not request a specific format.
3529 The <literal>stream</literal> argument is an &odr; stream which
3530 should be used for allocating space for structured data records.
3531 The stream will be reset when all records have been assembled, and
3532 the response package has been transmitted.
3533 For unstructured data, the backend is responsible for maintaining a
3534 static or dynamic buffer for the record between calls.
3537 If a SRU SearchRetrieveRequest is received by the frontend server,
3538 the <literal>referenceId</literal> is NULL and the
3539 <literal>format</literal> (transfer syntax) is the OID for XML.
3540 The schema for SRU is stored in both the
3541 <literal>Z_RecordComposition</literal>
3542 structure and <literal>schema</literal> (simple string).
3545 In the structure, the <literal>basename</literal> is the name of the
3546 database that holds the
3547 record. <literal>len</literal> is the length of the record returned, in
3548 bytes, and <literal>record</literal> is a pointer to the record.
3549 <literal>last_in_set</literal> should be nonzero only if the record
3550 returned is the last one in the given result set.
3551 <literal>errcode</literal> and <literal>errstring</literal>, if
3552 given, will be interpreted as a global error pertaining to the
3553 set, and will be returned in a non-surrogate-diagnostic.
3554 If you wish to return the error as a surrogate-diagnostic
3555 (local error) you can do this by setting
3556 <literal>surrogate_flag</literal> to 1 also.
3559 If the <literal>len</literal> field has the value -1, then
3560 <literal>record</literal> is assumed to point to a constructed data
3561 type. The <literal>format</literal> field will be used to determine
3562 which encoder should be used to serialize the data.
3566 If your backend generates structured records, it should use
3567 <function>odr_malloc()</function> on the provided stream for allocating
3568 data: This allows the frontend server to keep track of the record sizes.
3572 The <literal>format</literal> field is mapped to an object identifier
3573 in the direct reference of the resulting EXTERNAL representation
3578 The current version of &yaz; only supports the direct reference mode.
3582 int (*bend_present) (void *handle, bend_present_rr *rr);
3585 char *setname; /* set name */
3587 int number; /* record number */
3588 Odr_oid *format; /* format, transfer syntax (OID) */
3589 Z_ReferenceId *referenceId;/* reference ID */
3590 Z_RecordComposition *comp; /* Formatting instructions */
3591 ODR stream; /* encoding stream - memory source if required */
3592 ODR print; /* printing stream */
3593 bend_request request;
3594 bend_association association;
3596 int hits; /* number of hits */
3597 int errcode; /* 0==OK */
3598 char *errstring; /* system error string or NULL */
3602 The <function>bend_present</function> handler is called when
3603 the server receives a Z39.50 Present Request.
3604 The <literal>setname</literal>,
3605 <literal>start</literal> and <literal>number</literal> is the
3606 name of the result set - start position - and number of records to
3607 be retrieved respectively. <literal>format</literal> and
3608 <literal>comp</literal> is the preferred transfer syntax and element
3609 specifications of the present request.
3612 Note that this is handler serves as a supplement for
3613 <function>bend_fetch</function> and need not to be defined in order to
3614 support search - and retrieve.
3617 <sect2 id="server.delete">
3618 <title>Delete</title>
3620 For back-ends that supports delete of a result set only one handler
3624 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3626 typedef struct bend_delete_rr {
3630 Z_ReferenceId *referenceId;
3631 int delete_status; /* status for the whole operation */
3632 int *statuses; /* status each set - indexed as setnames */
3639 The delete set function definition is rather primitive, mostly because
3640 we have had no practical need for it as of yet. If someone wants
3641 to provide a full delete service, we'd be happy to add the
3642 extra parameters that are required. Are there clients out there
3643 that will actually delete sets they no longer need?
3647 <sect2 id="server.scan">
3650 For servers that wish to offer the scan service one handler
3654 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3657 BEND_SCAN_SUCCESS, /* ok */
3658 BEND_SCAN_PARTIAL /* not all entries could be found */
3661 typedef struct bend_scan_rr {
3662 int num_bases; /* number of elements in databaselist */
3663 char **basenames; /* databases to search */
3664 Odr_oid *attributeset;
3665 Z_ReferenceId *referenceId; /* reference ID */
3666 Z_AttributesPlusTerm *term;
3667 ODR stream; /* encoding stream - memory source if required */
3668 ODR print; /* printing stream */
3670 int *step_size; /* step size */
3671 int term_position; /* desired index of term in result list/returned */
3672 int num_entries; /* number of entries requested/returned */
3674 /* scan term entries. The called handler does not have
3675 to allocate this. Size of entries is num_entries (see above) */
3676 struct scan_entry *entries;
3677 bend_scan_status status;
3680 char *scanClause; /* CQL scan clause */
3681 char *setname; /* Scan in result set (NULL if omitted) */
3685 This backend server handles both Z39.50 scan
3686 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3687 Z39.50 Scan , it must check for a non-NULL value of
3688 <literal>scanClause</literal>.
3692 if designed today, it would be a choice using a union or similar,
3693 but that would break binary compatibility with existing servers.
3698 <sect1 id="server.invocation">
3699 <title>Application Invocation</title>
3701 The finished application has the following
3702 invocation syntax (by way of <function>statserv_main()</function>):
3710 A listener specification consists of a transport mode followed by a
3711 colon (:) followed by a listener address. The transport mode is
3712 either <literal>tcp</literal>, <literal>unix:</literal> or
3713 <literal>ssl</literal>.
3716 For TCP and SSL, an address has the form
3719 hostname | IP-number [: portnumber]
3722 The port number defaults to 210 (standard Z39.50 port).
3725 For UNIX, the address is the filename of socket.
3728 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3729 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3730 IPV4 binding as well (bindv6only=0),
3731 The special hostname <literal>@4</literal> binds to
3732 <literal>INADDR_ANY</literal> (IPV4 only listener).
3733 The special hostname <literal>@6</literal> binds to
3734 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3736 <example id="server.example.running.unix">
3737 <title>Running the GFS on Unix</title>
3739 Assuming the server application <replaceable>appname</replaceable> is
3740 started as root, the following will make it listen on port 210.
3741 The server will change identity to <literal>nobody</literal>
3742 and write its log to <filename>/var/log/app.log</filename>.
3744 application -l /var/log/app.log -u nobody tcp:@:210
3748 The server will accept Z39.50 requests and offer SRU service on port 210.
3751 <example id="server.example.apache.sru">
3752 <title>Setting up Apache as SRU Frontend</title>
3754 If you use <ulink url="&url.apache;">Apache</ulink>
3755 as your public web server and want to offer HTTP port 80
3756 access to the YAZ server on 210, you can use the
3757 <ulink url="&url.apache.directive.proxypass;">
3758 <literal>ProxyPass</literal></ulink>
3760 If you have virtual host
3761 <literal>srw.mydomain</literal> you can use the following directives
3762 in Apache's httpd.conf:
3765 ErrorLog /home/srw/logs/error_log
3766 TransferLog /home/srw/logs/access_log
3767 ProxyPass / http://srw.mydomain:210/
3772 The above for the Apache 1.3 series.
3775 <example id="server.example.local.access">
3776 <title>Running a server with local access only</title>
3778 Servers that is only being accessed from the local host should listen
3779 on UNIX file socket rather than a Internet socket. To listen on
3780 <filename>/tmp/mysocket</filename> start the server as follows:
3782 application unix:/tmp/mysocket
3787 <sect1 id="server.vhosts">
3788 <title>GFS Configuration and Virtual Hosts</title>
3793 <title>The Z39.50 ASN.1 Module</title>
3794 <sect1 id="asn.introduction">
3795 <title>Introduction</title>
3797 The &asn; module provides you with a set of C struct definitions for the
3798 various PDUs of the Z39.50 protocol, as well as for the complex types
3799 appearing within the PDUs. For the primitive data types, the C
3800 representation often takes the form of an ordinary C language type,
3801 such as <literal>Odr_int</literal> which is equivalent to an integral
3802 C integer. For ASN.1 constructs that have no direct
3803 representation in C, such as general octet strings and bit strings,
3804 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3805 provides auxiliary definitions.
3808 The &asn; module is located in sub directory <filename>z39.50</filename>.
3809 There you'll find C files that implements encoders and decoders for the
3810 Z39.50 types. You'll also find the protocol definitions:
3811 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3815 <sect1 id="asn.preparing">
3816 <title>Preparing PDUs</title>
3818 A structure representing a complex ASN.1 type doesn't in itself contain the
3819 members of that type. Instead, the structure contains
3820 <emphasis>pointers</emphasis> to the members of the type.
3821 This is necessary, in part, to allow a mechanism for specifying which
3822 of the optional structure (SEQUENCE) members are present, and which
3823 are not. It follows that you will need to somehow provide space for
3824 the individual members of the structure, and set the pointers to
3825 refer to the members.
3828 The conversion routines don't care how you allocate and maintain your
3829 C structures - they just follow the pointers that you provide.
3830 Depending on the complexity of your application, and your personal
3831 taste, there are at least three different approaches that you may take
3832 when you allocate the structures.
3835 You can use static or automatic local variables in the function that
3836 prepares the PDU. This is a simple approach, and it provides the most
3837 efficient form of memory management. While it works well for flat
3838 PDUs like the InitReqest, it will generally not be sufficient for say,
3839 the generation of an arbitrarily complex RPN query structure.
3842 You can individually create the structure and its members using the
3843 <function>malloc(2)</function> function. If you want to ensure that
3844 the data is freed when it is no longer needed, you will have to
3845 define a function that individually releases each member of a
3846 structure before freeing the structure itself.
3849 You can use the <function>odr_malloc()</function> function (see
3850 <xref linkend="odr.use"/> for details). When you use
3851 <function>odr_malloc()</function>, you can release all of the
3852 allocated data in a single operation, independent of any pointers and
3853 relations between the data. <function>odr_malloc()</function> is based on a
3854 "nibble-memory"
3855 scheme, in which large portions of memory are allocated, and then
3856 gradually handed out with each call to <function>odr_malloc()</function>.
3857 The next time you call <function>odr_reset()</function>, all of the
3858 memory allocated since the last call is recycled for future use (actually,
3859 it is placed on a free-list).
3862 You can combine all of the methods described here. This will often be
3863 the most practical approach. For instance, you might use
3864 <function>odr_malloc()</function> to allocate an entire structure and
3865 some of its elements, while you leave other elements pointing to global
3866 or per-session default variables.
3869 The &asn; module provides an important aid in creating new PDUs. For
3870 each of the PDU types (say, <function>Z_InitRequest</function>), a
3871 function is provided that allocates and initializes an instance of
3872 that PDU type for you. In the case of the InitRequest, the function is
3873 simply named <function>zget_InitRequest()</function>, and it sets up
3874 reasonable default value for all of the mandatory members. The optional
3875 members are generally initialized to null pointers. This last aspect
3876 is very important: it ensures that if the PDU definitions are
3877 extended after you finish your implementation (to accommodate
3878 new versions of the protocol, say), you won't get into trouble with
3879 uninitialized pointers in your structures. The functions use
3880 <function>odr_malloc()</function> to
3881 allocate the PDUs and its members, so you can free everything again with a
3882 single call to <function>odr_reset()</function>. We strongly recommend
3883 that you use the <literal>zget_*</literal>
3884 functions whenever you are preparing a PDU (in a C++ API, the
3885 <literal>zget_</literal>
3886 functions would probably be promoted to constructors for the
3890 The prototype for the individual PDU types generally look like this:
3893 Z_<type> *zget_<type>(ODR o);
3899 Z_InitRequest *zget_InitRequest(ODR o);
3902 The &odr; handle should generally be your encoding stream, but it
3906 As well as the individual PDU functions, a function
3907 <function>zget_APDU()</function> is provided, which allocates
3908 a top-level Z-APDU of the type requested:
3911 Z_APDU *zget_APDU(ODR o, int which);
3914 The <varname>which</varname> parameter is (of course) the discriminator
3915 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
3916 All of the interface described here is provided by the &asn; module, and
3917 you access it through the <filename>proto.h</filename> header file.
3920 <sect1 id="asn.external">
3921 <title>EXTERNAL Data</title>
3923 In order to achieve extensibility and adaptability to different
3924 application domains, the new version of the protocol defines many
3925 structures outside of the main ASN.1 specification, referencing them
3926 through ASN.1 EXTERNAL constructs. To simplify the construction and
3927 access to the externally referenced data, the &asn; module defines a
3928 specialized version of the EXTERNAL construct, called
3929 <literal>Z_External</literal>.It is defined thus:
3932 typedef struct Z_External
3934 Odr_oid *direct_reference;
3935 int *indirect_reference;
3940 Z_External_single = 0,
3942 Z_External_arbitrary,
3944 /* Specific types */
3946 Z_External_explainRecord,
3947 Z_External_resourceReport1,
3948 Z_External_resourceReport2
3956 Odr_any *single_ASN1_type;
3957 Odr_oct *octet_aligned;
3958 Odr_bitmask *arbitrary;
3960 /* Specific types */
3962 Z_ExplainRecord *explainRecord;
3963 Z_ResourceReport1 *resourceReport1;
3964 Z_ResourceReport2 *resourceReport2;
3972 When decoding, the &asn; module will attempt to determine which
3973 syntax describes the data by looking at the reference fields
3974 (currently only the direct-reference). For ASN.1 structured data, you
3975 need only consult the <literal>which</literal> field to determine the
3976 type of data. You can the access the data directly through the union.
3977 When constructing data for encoding, you set the union pointer to point
3978 to the data, and set the <literal>which</literal> field accordingly.
3979 Remember also to set the direct (or indirect) reference to the correct
3980 OID for the data type.
3981 For non-ASN.1 data such as MARC records, use the
3982 <literal>octet_aligned</literal> arm of the union.
3985 Some servers return ASN.1 structured data values (eg. database
3986 records) as BER-encoded records placed in the
3987 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
3988 The ASN-module will <emphasis>not</emphasis> automatically decode
3989 these records. To help you decode the records in the application, the
3993 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
3996 Can be used to retrieve information about the known, external data
3997 types. The function return a pointer to a static area, or NULL, if no
3998 match for the given direct reference is found. The
3999 <literal>Z_ext_typeent</literal>
4003 typedef struct Z_ext_typeent
4005 int oid[OID_SIZE]; /* the direct-reference OID. */
4006 int what; /* discriminator value for the external CHOICE */
4007 Odr_fun fun; /* decoder function */
4011 The <literal>what</literal> member contains the
4012 <literal>Z_External</literal> union discriminator value for the
4013 given type: For the SUTRS record syntax, the value would be
4014 <literal>Z_External_sutrs</literal>.
4015 The <literal>fun</literal> member contains a pointer to the
4016 function which encodes/decodes the given type. Again, for the SUTRS
4017 record syntax, the value of <literal>fun</literal> would be
4018 <literal>z_SUTRS</literal> (a function pointer).
4021 If you receive an EXTERNAL which contains an octet-string value that
4022 you suspect of being an ASN.1-structured data value, you can use
4023 <literal>z_ext_gettypebyref</literal> to look for the provided
4025 If the return value is different from NULL, you can use the provided
4026 function to decode the BER string (see <xref linkend="odr.use"/>
4030 If you want to <emphasis>send</emphasis> EXTERNALs containing
4031 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4032 is possible too. However, on the encoding phase, it requires a somewhat
4033 involved juggling around of the various buffers involved.
4036 If you need to add new, externally defined data types, you must update
4037 the struct above, in the source file <filename>prt-ext.h</filename>, as
4038 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4039 When changing the latter, remember to update both the
4040 <literal>arm</literal> arrary and the list
4041 <literal>type_table</literal>, which drives the CHOICE biasing that
4042 is necessary to tell the different, structured types apart
4047 Eventually, the EXTERNAL processing will most likely
4048 automatically insert the correct OIDs or indirect-refs. First,
4049 however, we need to determine how application-context management
4050 (specifically the presentation-context-list) should fit into the
4055 <sect1 id="asn.pdu">
4056 <title>PDU Contents Table</title>
4058 We include, for reference, a listing of the fields of each top-level
4059 PDU, as well as their default settings.
4061 <table frame="top" id="asn.default.initialize.request">
4062 <title>Default settings for PDU Initialize Request</title>
4064 <colspec colwidth="7*" colname="field"></colspec>
4065 <colspec colwidth="5*" colname="type"></colspec>
4066 <colspec colwidth="7*" colname="value"></colspec>
4069 <entry>Field</entry>
4071 <entry>Default Value</entry>
4076 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4079 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4082 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4085 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4088 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4091 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4094 implementationId</entry><entry>char*</entry><entry>"81"
4097 implementationName</entry><entry>char*</entry><entry>"YAZ"
4100 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4103 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4106 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4111 <table frame="top" id="asn.default.initialize.response">
4112 <title>Default settings for PDU Initialize Response</title>
4114 <colspec colwidth="7*" colname="field"></colspec>
4115 <colspec colwidth="5*" colname="type"></colspec>
4116 <colspec colwidth="7*" colname="value"></colspec>
4119 <entry>Field</entry>
4121 <entry>Default Value</entry>
4126 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4129 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4132 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4135 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4138 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4141 result</entry><entry>Odr_bool</entry><entry>TRUE
4144 implementationId</entry><entry>char*</entry><entry>"id)"
4147 implementationName</entry><entry>char*</entry><entry>"YAZ"
4150 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4153 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4156 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4161 <table frame="top" id="asn.default.search.request">
4162 <title>Default settings for PDU Search Request</title>
4164 <colspec colwidth="7*" colname="field"></colspec>
4165 <colspec colwidth="5*" colname="type"></colspec>
4166 <colspec colwidth="7*" colname="value"></colspec>
4169 <entry>Field</entry>
4171 <entry>Default Value</entry>
4176 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4179 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4182 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4185 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4188 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4191 resultSetName</entry><entry>char *</entry><entry>"default"
4194 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4197 databaseNames</entry><entry>char **</entry><entry>NULL
4200 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4204 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4208 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4211 query</entry><entry>Z_Query</entry><entry>NULL
4214 additionalSearchInfo</entry><entry>Z_OtherInformation
4218 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4223 <table frame="top" id="asn.default.search.response">
4224 <title>Default settings for PDU Search Response</title>
4226 <colspec colwidth="7*" colname="field"></colspec>
4227 <colspec colwidth="5*" colname="type"></colspec>
4228 <colspec colwidth="7*" colname="value"></colspec>
4231 <entry>Field</entry>
4233 <entry>Default Value</entry>
4238 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4241 resultCount</entry><entry>Odr_int</entry><entry>0
4244 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4247 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4250 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4253 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4256 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4259 records</entry><entry>Z_Records</entry><entry>NULL
4262 additionalSearchInfo</entry>
4263 <entry>Z_OtherInformation</entry><entry>NULL
4266 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4271 <table frame="top" id="asn.default.present.request">
4272 <title>Default settings for PDU Present Request</title>
4274 <colspec colwidth="7*" colname="field"></colspec>
4275 <colspec colwidth="5*" colname="type"></colspec>
4276 <colspec colwidth="7*" colname="value"></colspec>
4279 <entry>Field</entry>
4281 <entry>Default Value</entry>
4286 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4289 resultSetId</entry><entry>char*</entry><entry>"default"
4292 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4295 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4298 num_ranges</entry><entry>Odr_int</entry><entry>0
4301 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4304 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4307 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4310 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4313 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4316 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4319 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4324 <table frame="top" id="asn.default.present.response">
4325 <title>Default settings for PDU Present Response</title>
4327 <colspec colwidth="7*" colname="field"></colspec>
4328 <colspec colwidth="5*" colname="type"></colspec>
4329 <colspec colwidth="7*" colname="value"></colspec>
4332 <entry>Field</entry>
4334 <entry>Default Value</entry>
4339 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4342 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4345 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4348 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4351 records</entry><entry>Z_Records</entry><entry>NULL
4354 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4359 <table frame="top" id="asn.default.delete.result.set.request">
4360 <title>Default settings for Delete Result Set Request</title>
4362 <colspec colwidth="7*" colname="field"></colspec>
4363 <colspec colwidth="5*" colname="type"></colspec>
4364 <colspec colwidth="7*" colname="value"></colspec>
4367 <entry>Field</entry>
4369 <entry>Default Value</entry>
4373 <row><entry>referenceId
4374 </entry><entry>Z_ReferenceId</entry><entry>NULL
4377 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4380 num_ids</entry><entry>Odr_int</entry><entry>0
4383 resultSetList</entry><entry>char**</entry><entry>NULL
4386 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4391 <table frame="top" id="asn.default.delete.result.set.response">
4392 <title>Default settings for Delete Result Set Response</title>
4394 <colspec colwidth="7*" colname="field"></colspec>
4395 <colspec colwidth="5*" colname="type"></colspec>
4396 <colspec colwidth="7*" colname="value"></colspec>
4399 <entry>Field</entry>
4401 <entry>Default Value</entry>
4406 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4409 deleteOperationStatus</entry><entry>Odr_int</entry>
4410 <entry>Z_DeleteStatus_success</entry></row>
4412 num_statuses</entry><entry>Odr_int</entry><entry>0
4415 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4418 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4421 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4424 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4427 deleteMessage</entry><entry>char*</entry><entry>NULL
4430 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4435 <table frame="top" id="asn.default.scan.request">
4436 <title>Default settings for Scan Request</title>
4438 <colspec colwidth="7*" colname="field"></colspec>
4439 <colspec colwidth="5*" colname="type"></colspec>
4440 <colspec colwidth="7*" colname="value"></colspec>
4443 <entry>Field</entry>
4445 <entry>Default Value</entry>
4450 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4453 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4456 databaseNames</entry><entry>char**</entry><entry>NULL
4459 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4462 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4463 </entry><entry>NULL</entry></row>
4465 stepSize</entry><entry>Odr_int</entry><entry>NULL
4468 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4471 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4474 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4479 <table frame="top" id="asn.default.scan.response">
4480 <title>Default settings for Scan Response</title>
4482 <colspec colwidth="7*" colname="field"></colspec>
4483 <colspec colwidth="5*" colname="type"></colspec>
4484 <colspec colwidth="7*" colname="value"></colspec>
4487 <entry>Field</entry>
4489 <entry>Default Value</entry>
4494 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4497 stepSize</entry><entry>Odr_int</entry><entry>NULL
4500 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4503 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4506 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4509 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4512 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4515 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4520 <table frame="top" id="asn.default.trigger.resource.control.request">
4521 <title>Default settings for Trigger Resource Control Request</title>
4523 <colspec colwidth="7*" colname="field"></colspec>
4524 <colspec colwidth="5*" colname="type"></colspec>
4525 <colspec colwidth="7*" colname="value"></colspec>
4528 <entry>Field</entry>
4530 <entry>Default Value</entry>
4535 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4538 requestedAction</entry><entry>Odr_int</entry><entry>
4539 Z_TriggerResourceCtrl_resou..
4542 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4545 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4548 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4553 <table frame="top" id="asn.default.resource.control.request">
4554 <title>Default settings for Resource Control Request</title>
4556 <colspec colwidth="7*" colname="field"></colspec>
4557 <colspec colwidth="5*" colname="type"></colspec>
4558 <colspec colwidth="7*" colname="value"></colspec>
4561 <entry>Field</entry>
4563 <entry>Default Value</entry>
4568 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4571 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4574 resourceReport</entry><entry>Z_External</entry><entry>NULL
4577 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4580 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4583 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4586 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4591 <table frame="top" id="asn.default.resource.control.response">
4592 <title>Default settings for Resource Control Response</title>
4594 <colspec colwidth="7*" colname="field"></colspec>
4595 <colspec colwidth="5*" colname="type"></colspec>
4596 <colspec colwidth="7*" colname="value"></colspec>
4599 <entry>Field</entry>
4601 <entry>Default Value</entry>
4606 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4609 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4612 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4615 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4620 <table frame="top" id="asn.default.access.control.request">
4621 <title>Default settings for Access Control Request</title>
4623 <colspec colwidth="7*" colname="field"></colspec>
4624 <colspec colwidth="5*" colname="type"></colspec>
4625 <colspec colwidth="7*" colname="value"></colspec>
4628 <entry>Field</entry>
4630 <entry>Default Value</entry>
4635 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4638 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4641 u</entry><entry>union</entry><entry>NULL
4644 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4649 <table frame="top" id="asn.default.access.control.response">
4650 <title>Default settings for Access Control Response</title>
4652 <colspec colwidth="7*" colname="field"></colspec>
4653 <colspec colwidth="5*" colname="type"></colspec>
4654 <colspec colwidth="7*" colname="value"></colspec>
4657 <entry>Field</entry>
4659 <entry>Default Value</entry>
4664 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4667 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4670 u</entry><entry>union</entry><entry>NULL
4673 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4676 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4681 <table frame="top" id="asn.default.segment">
4682 <title>Default settings for Segment</title>
4684 <colspec colwidth="7*" colname="field"></colspec>
4685 <colspec colwidth="5*" colname="type"></colspec>
4686 <colspec colwidth="7*" colname="value"></colspec>
4689 <entry>Field</entry>
4691 <entry>Default Value</entry>
4696 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4699 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4702 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4705 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4707 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4712 <table frame="top" id="asn.default.close">
4713 <title>Default settings for Close</title>
4715 <colspec colwidth="7*" colname="field"></colspec>
4716 <colspec colwidth="5*" colname="type"></colspec>
4717 <colspec colwidth="7*" colname="value"></colspec>
4720 <entry>Field</entry>
4722 <entry>Default Value</entry>
4727 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4730 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4733 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4736 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4739 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4742 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4750 <title>SOAP and SRU</title>
4751 <sect1 id="soap.introduction">
4752 <title>Introduction</title>
4754 &yaz; uses a very simple implementation of
4755 <ulink url="&url.soap;">SOAP</ulink> that only,
4756 currenly, supports what is sufficient to offer SRU SOAP functionality.
4757 The implementation uses the
4758 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4759 libxml2 to encode and decode SOAP packages.
4762 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4763 simple C structs to represent SOAP packages as well as
4767 <sect1 id="soap.http">
4770 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4771 relatively easy to change that.
4774 The following definition of <literal>Z_GDU</literal> (Generic Data
4775 Unit) allows for both HTTP and Z39.50 in one packet.
4778 #include <yaz/zgdu.h>
4780 #define Z_GDU_Z3950 1
4781 #define Z_GDU_HTTP_Request 2
4782 #define Z_GDU_HTTP_Response 3
4787 Z_HTTP_Request *HTTP_Request;
4788 Z_HTTP_Response *HTTP_Response;
4793 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4794 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4796 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4797 is the HTTP Request and Response respectively.
4800 <sect1 id="soap.xml">
4801 <title>SOAP Packages</title>
4803 Every SOAP package in &yaz; is represented as follows:
4805 #include <yaz/soap.h>
4819 #define Z_SOAP_fault 1
4820 #define Z_SOAP_generic 2
4821 #define Z_SOAP_error 3
4825 Z_SOAP_Fault *fault;
4826 Z_SOAP_Generic *generic;
4827 Z_SOAP_Fault *soap_error;
4834 The <literal>fault</literal> and <literal>soap_error</literal>
4835 arms represent both a SOAP fault - struct
4836 <literal>Z_SOAP_Fault</literal>. Any other generic
4837 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
4840 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
4841 is the namespace for SOAP itself and reflects the SOAP
4842 version. For version 1.1 it is
4843 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
4844 for version 1.2 it is
4845 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
4848 int z_soap_codec(ODR o, Z_SOAP **pp,
4849 char **content_buf, int *content_len,
4850 Z_SOAP_Handler *handlers);
4853 The <literal>content_buf</literal> and <literal>content_len</literal>
4854 is XML buffer and length of buffer respectively.
4857 The <literal>handlers</literal> is a list of SOAP codec
4858 handlers - one handler for each service namespace. For SRU SOAP, the
4859 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
4862 When decoding, the <function>z_soap_codec</function>
4863 inspects the XML content
4864 and tries to match one of the services namespaces of the
4865 supplied handlers. If there is a match a handler function
4866 is invoked which decodes that particular SOAP package.
4867 If successful, the returned <literal>Z_SOAP</literal> package will be
4868 of type <literal>Z_SOAP_Generic</literal>.
4869 Member <literal>no</literal> is
4870 set the offset of handler that matched; <literal>ns</literal>
4871 is set to namespace of matching handler; the void pointer
4872 <literal>p</literal> is set to the C data structure assocatiated
4876 When a NULL namespace is met (member <literal>ns</literal> bwlow),
4877 that specifies end-of-list.
4880 Each handler is defined as follows:
4888 The <literal>ns</literal> is namespace of service associated with
4889 handler <literal>f</literal>. <literal>client_data</literal>
4890 is user-defined data which is passed to handler.
4893 The prototype for a SOAP service handler is:
4895 int handler(ODR o, void * ptr, void **handler_data,
4896 void *client_data, const char *ns);
4898 The <parameter>o</parameter> specifies the mode (decode/encode)
4899 as usual. The second argument, <parameter>ptr</parameter>,
4900 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
4901 and is a pointer to the <literal>Body</literal> element
4902 of the SOAP package. The <parameter>handler_data</parameter>
4903 is an opaque pointer to a C definitions associated with the
4904 SOAP service. <parameter>client_data</parameter> is the pointer
4905 which was set as part of the <literal>Z_SOAP_handler</literal>.
4906 Finally, <parameter>ns</parameter> the service namespace.
4909 <sect1 id="soap.srw">
4912 SRU SOAP is just one implementation of a SOAP handler as described
4913 in the previous section.
4914 The encoder/decoder handler for SRU is defined as
4917 #include <yaz/srw.h>
4919 int yaz_srw_codec(ODR o, void * pptr,
4920 Z_SRW_GDU **handler_data,
4921 void *client_data, const char *ns);
4923 Here, <literal>Z_SRW_GDU</literal> is either
4924 searchRetrieveRequest or a searchRetrieveResponse.
4928 The xQuery and xSortKeys are not handled yet by
4929 the SRW implementation of &yaz;. Explain is also missing.
4930 Future versions of &yaz; will include these features.
4934 The definition of searchRetrieveRequest is:
4938 #define Z_SRW_query_type_cql 1
4939 #define Z_SRW_query_type_xcql 2
4940 #define Z_SRW_query_type_pqf 3
4948 #define Z_SRW_sort_type_none 1
4949 #define Z_SRW_sort_type_sort 2
4950 #define Z_SRW_sort_type_xSort 3
4958 int *maximumRecords;
4960 char *recordPacking;
4962 } Z_SRW_searchRetrieveRequest;
4964 Please observe that data of type xsd:string is represented
4965 as a char pointer (<literal>char *</literal>). A null pointer
4966 means that the element is absent.
4967 Data of type xsd:integer is representd as a pointer to
4968 an int (<literal>int *</literal>). Again, a null pointer
4969 us used for absent elements.
4972 The SearchRetrieveResponse has the following definition.
4975 int * numberOfRecords;
4977 int * resultSetIdleTime;
4979 Z_SRW_record *records;
4982 Z_SRW_diagnostic *diagnostics;
4983 int num_diagnostics;
4984 int *nextRecordPosition;
4985 } Z_SRW_searchRetrieveResponse;
4987 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
4988 is number of returned records and diagnostics respectively and also
4989 correspond to the "size of" arrays <literal>records</literal>
4990 and <literal>diagnostics</literal>.
4993 A retrieval record is defined as follows:
4997 char *recordData_buf;
4999 int *recordPosition;
5002 The record data is defined as a buffer of some length so that
5003 data can be of any type. SRW 1.0 currenly doesn't allow for this
5004 (only XML), but future versions might do.
5007 And, a diagnostic as:
5017 <chapter id="tools">
5018 <title>Supporting Tools</title>
5020 In support of the service API - primarily the ASN module, which
5021 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5022 a collection of tools that support the development of applications.
5024 <sect1 id="tools.query">
5025 <title>Query Syntax Parsers</title>
5027 Since the type-1 (RPN) query structure has no direct, useful string
5028 representation, every origin application needs to provide some form of
5029 mapping from a local query notation or representation to a
5030 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5031 construct the query manually, perhaps using
5032 <function>odr_malloc()</function> to simplify memory management.
5033 The &yaz; distribution includes three separate, query-generating tools
5034 that may be of use to you.
5037 <title>Prefix Query Format</title>
5039 Since RPN or reverse polish notation is really just a fancy way of
5040 describing a suffix notation format (operator follows operands), it
5041 would seem that the confusion is total when we now introduce a prefix
5042 notation for RPN. The reason is one of simple laziness - it's somewhat
5043 simpler to interpret a prefix format, and this utility was designed
5044 for maximum simplicity, to provide a baseline representation for use
5045 in simple test applications and scripting environments (like Tcl). The
5046 demonstration client included with YAZ uses the PQF.
5050 The PQF have been adopted by other parties developing Z39.50
5051 software. It is often referred to as Prefix Query Notation
5056 The PQF is defined by the pquery module in the YAZ library.
5057 There are two sets of function that have similar behavior. First
5058 set operates on a PQF parser handle, second set doesn't. First set
5059 set of functions are more flexible than the second set. Second set
5060 is obsolete and is only provided to ensure backwards compatibility.
5063 First set of functions all operate on a PQF parser handle:
5066 #include <yaz/pquery.h>
5068 YAZ_PQF_Parser yaz_pqf_create(void);
5070 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5072 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5074 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5075 Odr_oid **attributeSetId, const char *qbuf);
5077 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5080 A PQF parser is created and destructed by functions
5081 <function>yaz_pqf_create</function> and
5082 <function>yaz_pqf_destroy</function> respectively.
5083 Function <function>yaz_pqf_parse</function> parses query given
5084 by string <literal>qbuf</literal>. If parsing was successful,
5085 a Z39.50 RPN Query is returned which is created using ODR stream
5086 <literal>o</literal>. If parsing failed, a NULL pointer is
5088 Function <function>yaz_pqf_scan</function> takes a scan query in
5089 <literal>qbuf</literal>. If parsing was successful, the function
5090 returns attributes plus term pointer and modifies
5091 <literal>attributeSetId</literal> to hold attribute set for the
5092 scan request - both allocated using ODR stream <literal>o</literal>.
5093 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5094 Error information for bad queries can be obtained by a call to
5095 <function>yaz_pqf_error</function> which returns an error code and
5096 modifies <literal>*msg</literal> to point to an error description,
5097 and modifies <literal>*off</literal> to the offset within last
5098 query were parsing failed.
5101 The second set of functions are declared as follows:
5104 #include <yaz/pquery.h>
5106 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5108 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5109 Odr_oid **attributeSetP, const char *qbuf);
5111 int p_query_attset(const char *arg);
5114 The function <function>p_query_rpn()</function> takes as arguments an
5115 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5116 to provide a memory source (the structure created is released on
5117 the next call to <function>odr_reset()</function> on the stream), a
5118 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5119 <token>PROTO_SR</token>), an attribute set reference, and
5120 finally a null-terminated string holding the query string.
5123 If the parse went well, <function>p_query_rpn()</function> returns a
5124 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5125 placed directly into a <literal>Z_SearchRequest</literal>.
5126 If parsing failed, due to syntax error, a NULL pointer is returned.
5129 The <literal>p_query_attset</literal> specifies which attribute set
5130 to use if the query doesn't specify one by the
5131 <literal>@attrset</literal> operator.
5132 The <literal>p_query_attset</literal> returns 0 if the argument is a
5133 valid attribute set specifier; otherwise the function returns -1.
5136 The grammar of the PQF is as follows:
5139 query ::= top-set query-struct.
5141 top-set ::= [ '@attrset' string ]
5143 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5145 attr-spec ::= '@attr' [ string ] string query-struct
5147 complex ::= operator query-struct query-struct.
5149 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5151 simple ::= result-set | term.
5153 result-set ::= '@set' string.
5157 proximity ::= exclusion distance ordered relation which-code unit-code.
5159 exclusion ::= '1' | '0' | 'void'.
5161 distance ::= integer.
5163 ordered ::= '1' | '0'.
5165 relation ::= integer.
5167 which-code ::= 'known' | 'private' | integer.
5169 unit-code ::= integer.
5171 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5174 You will note that the syntax above is a fairly faithful
5175 representation of RPN, except for the Attribute, which has been
5176 moved a step away from the term, allowing you to associate one or more
5177 attributes with an entire query structure. The parser will
5178 automatically apply the given attributes to each term as required.
5181 The @attr operator is followed by an attribute specification
5182 (<literal>attr-spec</literal> above). The specification consists
5183 of an optional attribute set, an attribute type-value pair and
5184 a sub-query. The attribute type-value pair is packed in one string:
5185 an attribute type, an equals sign, and an attribute value, like this:
5186 <literal>@attr 1=1003</literal>.
5187 The type is always an integer but the value may be either an
5188 integer or a string (if it doesn't start with a digit character).
5189 A string attribute-value is encoded as a Type-1 ``complex''
5190 attribute with the list of values containing the single string
5191 specified, and including no semantic indicators.
5194 Version 3 of the Z39.50 specification defines various encoding of terms.
5195 Use <literal>@term </literal> <replaceable>type</replaceable>
5196 <replaceable>string</replaceable>,
5197 where type is one of: <literal>general</literal>,
5198 <literal>numeric</literal> or <literal>string</literal>
5199 (for InternationalString).
5200 If no term type has been given, the <literal>general</literal> form
5201 is used. This is the only encoding allowed in both versions 2 and 3
5202 of the Z39.50 standard.
5204 <sect3 id="PQF-prox">
5205 <title>Using Proximity Operators with PQF</title>
5208 This is an advanced topic, describing how to construct
5209 queries that make very specific requirements on the
5210 relative location of their operands.
5211 You may wish to skip this section and go straight to
5212 <link linkend="pqf-examples">the example PQF queries</link>.
5217 Most Z39.50 servers do not support proximity searching, or
5218 support only a small subset of the full functionality that
5219 can be expressed using the PQF proximity operator. Be
5220 aware that the ability to <emphasis>express</emphasis> a
5221 query in PQF is no guarantee that any given server will
5222 be able to <emphasis>execute</emphasis> it.
5228 The proximity operator <literal>@prox</literal> is a special
5229 and more restrictive version of the conjunction operator
5230 <literal>@and</literal>. Its semantics are described in
5231 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5232 can be read on-line at
5233 <ulink url="&url.z39.50.proximity;"/>
5236 In PQF, the proximity operation is represented by a sequence
5239 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5241 in which the meanings of the parameters are as described in in
5242 the standard, and they can take the following values:
5245 <formalpara><title>exclusion</title>
5247 0 = false (i.e. the proximity condition specified by the
5248 remaining parameters must be satisfied) or
5249 1 = true (the proximity condition specified by the
5250 remaining parameters must <emphasis>not</emphasis> be
5256 <formalpara><title>distance</title><para>
5257 An integer specifying the difference between the locations
5258 of the operands: e.g. two adjacent words would have
5259 distance=1 since their locations differ by one unit.
5261 </formalpara></listitem>
5263 <formalpara><title>ordered</title><para>
5264 1 = ordered (the operands must occur in the order the
5265 query specifies them) or
5266 0 = unordered (they may appear in either order).
5271 <formalpara><title>relation</title><para>
5272 Recognised values are
5274 2 (lessThanOrEqual),
5276 4 (greaterThanOrEqual),
5283 <formalpara><title>which-code</title><para>
5284 <literal>known</literal>
5286 <literal>k</literal>
5287 (the unit-code parameter is taken from the well-known list
5288 of alternatives described in below) or
5289 <literal>private</literal>
5291 <literal>p</literal>
5292 (the unit-code paramater has semantics specific to an
5293 out-of-band agreement such as a profile).
5298 <formalpara><title>unit-code</title><para>
5299 If the which-code parameter is <literal>known</literal>
5300 then the recognised values are
5310 10 (elementType) and
5312 If which-code is <literal>private</literal> then the
5313 acceptable values are determined by the profile.
5318 (The numeric values of the relation and well-known unit-code
5319 parameters are taken straight from
5320 <ulink url="&url.z39.50.proximity.asn1;"
5321 >the ASN.1</ulink> of the proximity structure in the standard.)
5324 <sect3 id="pqf-examples">
5325 <title>PQF queries</title>
5326 <example id="example.pqf.simple.terms">
5327 <title>PQF queries using simple terms</title>
5336 <example id="pqf.example.pqf.boolean.operators">
5337 <title>PQF boolean operators</title>
5340 @or "dylan" "zimmerman"
5342 @and @or dylan zimmerman when
5344 @and when @or dylan zimmerman
5348 <example id="example.pqf.result.sets">
5349 <title>PQF references to result sets</title>
5354 @and @set seta @set setb
5358 <example id="example.pqf.attributes">
5359 <title>Attributes for terms</title>
5364 @attr 1=4 @attr 4=1 "self portrait"
5366 @attrset exp1 @attr 1=1 CategoryList
5368 @attr gils 1=2008 Copenhagen
5370 @attr 1=/book/title computer
5374 <example id="example.pqf.proximity">
5375 <title>PQF Proximity queries</title>
5378 @prox 0 3 1 2 k 2 dylan zimmerman
5380 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5381 distance, ordered, relation, which-code and unit-code, in that
5385 <para>exclusion = 0: the proximity condition must hold</para>
5388 <para>distance = 3: the terms must be three units apart</para>
5392 ordered = 1: they must occur in the order they are specified
5397 relation = 2: lessThanOrEqual (to the distance of 3 units)
5402 which-code is ``known'', so the standard unit-codes are used
5406 <para>unit-code = 2: word.</para>
5409 So the whole proximity query means that the words
5410 <literal>dylan</literal> and <literal>zimmerman</literal> must
5411 both occur in the record, in that order, differing in position
5412 by three or fewer words (i.e. with two or fewer words between
5413 them.) The query would find ``Bob Dylan, aka. Robert
5414 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5415 since the distance in this case is four.
5418 <example id="example.pqf.search.term.type">
5419 <title>PQF specification of search term type</title>
5422 @term string "a UTF-8 string, maybe?"
5426 <example id="example.pqf.mixed.queries">
5427 <title>PQF mixed queries</title>
5430 @or @and bob dylan @set Result-1
5432 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5434 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5436 The last of these examples is a spatial search: in
5437 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5438 >the GILS attribute set</ulink>,
5440 2038 indicates West Bounding Coordinate and
5441 2030 indicates East Bounding Coordinate,
5442 so the query is for areas extending from -114 degrees
5443 to no more than -109 degrees.
5448 <sect2 id="CCL"><title>CCL</title>
5450 Not all users enjoy typing in prefix query structures and numerical
5451 attribute values, even in a minimalistic test client. In the library
5452 world, the more intuitive Common Command Language - CCL (ISO 8777)
5453 has enjoyed some popularity - especially before the widespread
5454 availability of graphical interfaces. It is still useful in
5455 applications where you for some reason or other need to provide a
5456 symbolic language for expressing boolean query structures.
5458 <sect3 id="ccl.syntax">
5459 <title>CCL Syntax</title>
5461 The CCL parser obeys the following grammar for the FIND argument.
5462 The syntax is annotated by in the lines prefixed by
5463 <literal>--</literal>.
5466 CCL-Find ::= CCL-Find Op Elements
5469 Op ::= "and" | "or" | "not"
5470 -- The above means that Elements are separated by boolean operators.
5472 Elements ::= '(' CCL-Find ')'
5475 | Qualifiers Relation Terms
5476 | Qualifiers Relation '(' CCL-Find ')'
5477 | Qualifiers '=' string '-' string
5478 -- Elements is either a recursive definition, a result set reference, a
5479 -- list of terms, qualifiers followed by terms, qualifiers followed
5480 -- by a recursive definition or qualifiers in a range (lower - upper).
5482 Set ::= 'set' = string
5483 -- Reference to a result set
5485 Terms ::= Terms Prox Term
5487 -- Proximity of terms.
5489 Term ::= Term string
5491 -- This basically means that a term may include a blank
5493 Qualifiers ::= Qualifiers ',' string
5495 -- Qualifiers is a list of strings separated by comma
5497 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5498 -- Relational operators. This really doesn't follow the ISO8777
5502 -- Proximity operator
5505 <example id="example.ccl.queries">
5506 <title>CCL queries</title>
5508 The following queries are all valid:
5519 (dylan and bob) or set=1
5528 Assuming that the qualifiers <literal>ti</literal>,
5529 <literal>au</literal>
5530 and <literal>date</literal> are defined we may use:
5535 au=(bob dylan and slow train coming)
5537 date>1980 and (ti=((self portrait)))
5541 <sect3 id="ccl.qualifiers">
5542 <title>CCL Qualifiers</title>
5544 Qualifiers are used to direct the search to a particular searchable
5545 index, such as title (ti) and author indexes (au). The CCL standard
5546 itself doesn't specify a particular set of qualifiers, but it does
5547 suggest a few short-hand notations. You can customize the CCL parser
5548 to support a particular set of qualifiers to reflect the current target
5549 profile. Traditionally, a qualifier would map to a particular
5550 use-attribute within the BIB-1 attribute set. It is also
5551 possible to set other attributes, such as the structure
5555 A CCL profile is a set of predefined CCL qualifiers that may be
5556 read from a file or set in the CCL API.
5557 The YAZ client reads its CCL qualifiers from a file named
5558 <filename>default.bib</filename>. There are four types of
5559 lines in a CCL profile: qualifier specification,
5560 qualifier alias, comments and directives.
5562 <sect4 id="ccl.qualifier.specification">
5563 <title>Qualifier specification</title>
5565 A qualifier specification is of the form:
5568 <replaceable>qualifier-name</replaceable>
5569 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5570 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5573 where <replaceable>qualifier-name</replaceable> is the name of the
5574 qualifier to be used (eg. <literal>ti</literal>),
5575 <replaceable>type</replaceable> is attribute type in the attribute
5576 set (Bib-1 is used if no attribute set is given) and
5577 <replaceable>val</replaceable> is attribute value.
5578 The <replaceable>type</replaceable> can be specified as an
5579 integer or as it be specified either as a single-letter:
5580 <literal>u</literal> for use,
5581 <literal>r</literal> for relation,<literal>p</literal> for position,
5582 <literal>s</literal> for structure,<literal>t</literal> for truncation
5583 or <literal>c</literal> for completeness.
5584 The attributes for the special qualifier name <literal>term</literal>
5585 are used when no CCL qualifier is given in a query.
5586 <table id="ccl.common.bib1.attributes">
5587 <title>Common Bib-1 attributes</title>
5589 <colspec colwidth="2*" colname="type"></colspec>
5590 <colspec colwidth="9*" colname="description"></colspec>
5594 <entry>Description</entry>
5599 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5601 Use attribute (1). Common use attributes are
5602 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5603 62 Subject, 1003 Author), 1016 Any. Specify value
5608 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5610 Relation attribute (2). Common values are
5611 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5612 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5616 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5618 Position attribute (3). Values: 1 first in field, 2
5619 first in any subfield, 3 any position in field.
5623 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5625 Structure attribute (4). Values: 1 phrase, 2 word,
5626 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5627 101 name (norm), 102 name (un), 103 structure, 104 urx,
5628 105 free-form-text, 106 document-text, 107 local-number,
5629 108 string, 109 numeric string.
5633 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5635 Truncation attribute (5). Values: 1 right, 2 left,
5636 3 left& right, 100 none, 101 process #, 102 regular-1,
5637 103 regular-2, 104 CCL.
5641 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5643 Completeness attribute (6). Values: 1 incomplete subfield,
5644 2 complete subfield, 3 complete field.
5652 Refer to <xref linkend="bib1"/> or the complete
5653 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5656 It is also possible to specify non-numeric attribute values,
5657 which are used in combination with certain types.
5658 The special combinations are:
5659 <table id="ccl.special.attribute.combos">
5660 <title>Special attribute combos</title>
5662 <colspec colwidth="2*" colname="name"></colspec>
5663 <colspec colwidth="9*" colname="description"></colspec>
5667 <entry>Description</entry>
5672 <entry><literal>s=pw</literal></entry>
5674 The structure is set to either word or phrase depending
5675 on the number of tokens in a term (phrase-word).
5679 <entry><literal>s=al</literal></entry>
5681 Each token in the term is ANDed. (and-list).
5682 This does not set the structure at all.
5685 <row><entry><literal>s=ol</literal></entry>
5687 Each token in the term is ORed. (or-list).
5688 This does not set the structure at all.
5691 <row><entry><literal>s=ag</literal></entry>
5693 Tokens that appears as phrases (with blank in them) gets
5694 structure phrase attached (4=1). Tokens that appear to be words
5695 gets structure word attached (4=2). Phrases and words are
5696 ANDed. This is a variant of s=al and s=pw, with the main
5697 difference that words are not split (with operator AND)
5698 but instead kept in one RPN token. This facility appeared
5702 <row><entry><literal>r=o</literal></entry>
5704 Allows ranges and the operators greather-than, less-than, ...
5706 This sets Bib-1 relation attribute accordingly (relation
5707 ordered). A query construct is only treated as a range if
5708 dash is used and that is surrounded by white-space. So
5709 <literal>-1980</literal> is treated as term
5710 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5711 If <literal>- 1980</literal> is used, however, that is
5715 <row><entry><literal>r=r</literal></entry>
5717 Similar to <literal>r=o</literal> but assumes that terms
5718 are non-negative (not prefixed with <literal>-</literal>).
5719 Thus, a dash will always be treated as a range.
5720 The construct <literal>1980-1990</literal> is
5721 treated as a range with <literal>r=r</literal> but as a
5722 single term <literal>"1980-1990"</literal> with
5723 <literal>r=o</literal>. The special attribute
5724 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5727 <row><entry><literal>r=omiteq</literal></entry>
5729 This will omit relation=equals (@attr 2=3) when r=o / r=r
5730 is used. This is useful for servers that somehow breaks
5731 when an explicit relation=equals is used. Omitting the
5732 relation is usually safe because "equals" is the default
5733 behavior. This tweak was added in YAZ version 5.1.2.
5736 <row><entry><literal>t=l</literal></entry>
5738 Allows term to be left-truncated.
5739 If term is of the form <literal>?x</literal>, the resulting
5740 Type-1 term is <literal>x</literal> and truncation is left.
5743 <row><entry><literal>t=r</literal></entry>
5745 Allows term to be right-truncated.
5746 If term is of the form <literal>x?</literal>, the resulting
5747 Type-1 term is <literal>x</literal> and truncation is right.
5750 <row><entry><literal>t=n</literal></entry>
5752 If term is does not include <literal>?</literal>, the
5753 truncation attribute is set to none (100).
5756 <row><entry><literal>t=b</literal></entry>
5758 Allows term to be both left&right truncated.
5759 If term is of the form <literal>?x?</literal>, the
5760 resulting term is <literal>x</literal> and trunctation is
5761 set to both left&right.
5764 <row><entry><literal>t=x</literal></entry>
5766 Allows masking anywhere in a term, thus fully supporting
5767 # (mask one character) and ? (zero or more of any).
5768 If masking is used, trunction is set to 102 (regexp-1 in term)
5769 and the term is converted accordingly to a regular expression.
5772 <row><entry><literal>t=z</literal></entry>
5774 Allows masking anywhere in a term, thus fully supporting
5775 # (mask one character) and ? (zero or more of any).
5776 If masking is used, trunction is set to 104 (Z39.58 in term)
5777 and the term is converted accordingly to Z39.58 masking term -
5778 actually the same truncation as CCL itself.
5785 <example id="example.ccl.profile">
5786 <title>CCL profile</title>
5788 Consider the following definition:
5798 <literal>ti</literal> and <literal>au</literal> both set
5799 structure attribute to phrase (s=1).
5800 <literal>ti</literal>
5801 sets the use-attribute to 4. <literal>au</literal> sets the
5803 When no qualifiers are used in the query the structure-attribute is
5804 set to free-form-text (105) (rule for <literal>term</literal>).
5805 The <literal>date</literal> sets the relation attribute to
5806 the relation used in the CCL query and sets the use attribute
5810 You can combine attributes. To Search for "ranked title" you
5813 ti,ranked=knuth computer
5815 which will set relation=ranked, use=title, structure=phrase.
5822 is a valid query. But
5830 <sect4 id="ccl.qualifier.alias">
5831 <title>Qualifier alias</title>
5833 A qualifier alias is of the form:
5836 <replaceable>q</replaceable>
5837 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
5840 which declares <replaceable>q</replaceable> to
5841 be an alias for <replaceable>q1</replaceable>,
5842 <replaceable>q2</replaceable>... such that the CCL
5843 query <replaceable>q=x</replaceable> is equivalent to
5844 <replaceable>q1=x or q2=x or ...</replaceable>.
5847 <sect4 id="ccl.comments">
5848 <title>Comments</title>
5850 Lines with white space or lines that begin with
5851 character <literal>#</literal> are treated as comments.
5854 <sect4 id="ccl.directives">
5855 <title>Directives</title>
5857 Directive specifications takes the form
5859 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
5861 <table id="ccl.directives.table">
5862 <title>CCL directives</title>
5864 <colspec colwidth="2*" colname="name"></colspec>
5865 <colspec colwidth="8*" colname="description"></colspec>
5866 <colspec colwidth="1*" colname="default"></colspec>
5870 <entry>Description</entry>
5871 <entry>Default</entry>
5876 <entry>truncation</entry>
5877 <entry>Truncation character</entry>
5878 <entry><literal>?</literal></entry>
5882 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
5883 <entry><literal>#</literal></entry>
5886 <entry>field</entry>
5887 <entry>Specifies how multiple fields are to be
5888 combined. There are two modes: <literal>or</literal>:
5889 multiple qualifier fields are ORed,
5890 <literal>merge</literal>: attributes for the qualifier
5891 fields are merged and assigned to one term.
5893 <entry><literal>merge</literal></entry>
5897 <entry>Specifies if CCL operators and qualifiers should be
5898 compared with case sensitivity or not. Specify 1 for
5899 case sensitive; 0 for case insensitive.</entry>
5900 <entry><literal>1</literal></entry>
5904 <entry>Specifies token for CCL operator AND.</entry>
5905 <entry><literal>and</literal></entry>
5909 <entry>Specifies token for CCL operator OR.</entry>
5910 <entry><literal>or</literal></entry>
5914 <entry>Specifies token for CCL operator NOT.</entry>
5915 <entry><literal>not</literal></entry>
5919 <entry>Specifies token for CCL operator SET.</entry>
5920 <entry><literal>set</literal></entry>
5927 <sect3 id="ccl.api">
5928 <title>CCL API</title>
5930 All public definitions can be found in the header file
5931 <filename>ccl.h</filename>. A profile identifier is of type
5932 <literal>CCL_bibset</literal>. A profile must be created with the call
5933 to the function <function>ccl_qual_mk</function> which returns a profile
5934 handle of type <literal>CCL_bibset</literal>.
5937 To read a file containing qualifier definitions the function
5938 <function>ccl_qual_file</function> may be convenient. This function
5939 takes an already opened <literal>FILE</literal> handle pointer as
5940 argument along with a <literal>CCL_bibset</literal> handle.
5943 To parse a simple string with a FIND query use the function
5946 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
5947 int *error, int *pos);
5950 which takes the CCL profile (<literal>bibset</literal>) and query
5951 (<literal>str</literal>) as input. Upon successful completion the RPN
5952 tree is returned. If an error occur, such as a syntax error, the integer
5953 pointed to by <literal>error</literal> holds the error code and
5954 <literal>pos</literal> holds the offset inside query string in which
5958 An English representation of the error may be obtained by calling
5959 the <literal>ccl_err_msg</literal> function. The error codes are
5960 listed in <filename>ccl.h</filename>.
5963 To convert the CCL RPN tree (type
5964 <literal>struct ccl_rpn_node *</literal>)
5965 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
5966 must be used. This function which is part of YAZ is implemented in
5967 <filename>yaz-ccl.c</filename>.
5968 After calling this function the CCL RPN tree is probably no longer
5969 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
5972 A CCL profile may be destroyed by calling the
5973 <function>ccl_qual_rm</function> function.
5976 The token names for the CCL operators may be changed by setting the
5977 globals (all type <literal>char *</literal>)
5978 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
5979 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
5980 An operator may have aliases, i.e. there may be more than one name for
5981 the operator. To do this, separate each alias with a space character.
5988 <ulink url="&url.cql;">CQL</ulink>
5989 - Common Query Language - was defined for the
5990 <ulink url="&url.sru;">SRU</ulink> protocol.
5991 In many ways CQL has a similar syntax to CCL.
5992 The objective of CQL is different. Where CCL aims to be
5993 an end-user language, CQL is <emphasis>the</emphasis> protocol
5994 query language for SRU.
5998 If you are new to CQL, read the
5999 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6003 The CQL parser in &yaz; provides the following:
6007 It parses and validates a CQL query.
6012 It generates a C structure that allows you to convert
6013 a CQL query to some other query language, such as SQL.
6018 The parser converts a valid CQL query to PQF, thus providing a
6019 way to use CQL for both SRU servers and Z39.50 targets at the
6025 The parser converts CQL to XCQL.
6026 XCQL is an XML representation of CQL.
6027 XCQL is part of the SRU specification. However, since SRU
6028 supports CQL only, we don't expect XCQL to be widely used.
6029 Furthermore, CQL has the advantage over XCQL that it is
6035 <sect3 id="cql.parsing">
6036 <title>CQL parsing</title>
6038 A CQL parser is represented by the <literal>CQL_parser</literal>
6039 handle. Its contents should be considered &yaz; internal (private).
6041 #include <yaz/cql.h>
6043 typedef struct cql_parser *CQL_parser;
6045 CQL_parser cql_parser_create(void);
6046 void cql_parser_destroy(CQL_parser cp);
6048 A parser is created by <function>cql_parser_create</function> and
6049 is destroyed by <function>cql_parser_destroy</function>.
6052 To parse a CQL query string, the following function
6055 int cql_parser_string(CQL_parser cp, const char *str);
6057 A CQL query is parsed by the <function>cql_parser_string</function>
6058 which takes a query <parameter>str</parameter>.
6059 If the query was valid (no syntax errors), then zero is returned;
6060 otherwise -1 is returned to indicate a syntax error.
6064 int cql_parser_stream(CQL_parser cp,
6065 int (*getbyte)(void *client_data),
6066 void (*ungetbyte)(int b, void *client_data),
6069 int cql_parser_stdio(CQL_parser cp, FILE *f);
6071 The functions <function>cql_parser_stream</function> and
6072 <function>cql_parser_stdio</function> parses a CQL query
6073 - just like <function>cql_parser_string</function>.
6074 The only difference is that the CQL query can be
6075 fed to the parser in different ways.
6076 The <function>cql_parser_stream</function> uses a generic
6077 byte stream as input. The <function>cql_parser_stdio</function>
6078 uses a <literal>FILE</literal> handle which is opened for reading.
6081 <sect3 id="cql.tree">
6082 <title>CQL tree</title>
6084 The the query string is valid, the CQL parser
6085 generates a tree representing the structure of the
6090 struct cql_node *cql_parser_result(CQL_parser cp);
6092 <function>cql_parser_result</function> returns the
6093 a pointer to the root node of the resulting tree.
6096 Each node in a CQL tree is represented by a
6097 <literal>struct cql_node</literal>.
6098 It is defined as follows:
6100 #define CQL_NODE_ST 1
6101 #define CQL_NODE_BOOL 2
6102 #define CQL_NODE_SORT 3
6112 struct cql_node *modifiers;
6116 struct cql_node *left;
6117 struct cql_node *right;
6118 struct cql_node *modifiers;
6122 struct cql_node *next;
6123 struct cql_node *modifiers;
6124 struct cql_node *search;
6129 There are three node types: search term (ST), boolean (BOOL)
6131 A modifier is treated as a search term too.
6134 The search term node has five members:
6138 <literal>index</literal>: index for search term.
6139 If an index is unspecified for a search term,
6140 <literal>index</literal> will be NULL.
6145 <literal>index_uri</literal>: index URi for search term
6146 or NULL if none could be resolved for the index.
6151 <literal>term</literal>: the search term itself.
6156 <literal>relation</literal>: relation for search term.
6161 <literal>relation_uri</literal>: relation URI for search term.
6166 <literal>modifiers</literal>: relation modifiers for search
6167 term. The <literal>modifiers</literal> list itself of cql_nodes
6168 each of type <literal>ST</literal>.
6174 The boolean node represents <literal>and</literal>,
6175 <literal>or</literal>, <literal>not</literal> +
6180 <literal>left</literal> and <literal>right</literal>: left
6181 - and right operand respectively.
6186 <literal>modifiers</literal>: proximity arguments.
6192 The sort node represents both the SORTBY clause.
6195 <sect3 id="cql.to.pqf">
6196 <title>CQL to PQF conversion</title>
6198 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6199 that the resulting RPN depends on the Z39.50 target
6200 capabilities (combinations of supported attributes).
6201 In addition, the CQL and SRU operates on index prefixes
6202 (URI or strings), whereas the RPN uses Object Identifiers
6206 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6207 type. It represents a particular mapping between CQL and RPN.
6208 This handle is created and destroyed by the functions:
6210 cql_transform_t cql_transform_open_FILE (FILE *f);
6211 cql_transform_t cql_transform_open_fname(const char *fname);
6212 void cql_transform_close(cql_transform_t ct);
6214 The first two functions create a tranformation handle from
6215 either an already open FILE or from a filename respectively.
6218 The handle is destroyed by <function>cql_transform_close</function>
6219 in which case no further reference of the handle is allowed.
6222 When a <literal>cql_transform_t</literal> handle has been created
6223 you can convert to RPN.
6225 int cql_transform_buf(cql_transform_t ct,
6226 struct cql_node *cn, char *out, int max);
6228 This function converts the CQL tree <literal>cn</literal>
6229 using handle <literal>ct</literal>.
6230 For the resulting PQF, you supply a buffer <literal>out</literal>
6231 which must be able to hold at at least <literal>max</literal>
6235 If conversion failed, <function>cql_transform_buf</function>
6236 returns a non-zero SRU error code; otherwise zero is returned
6237 (conversion successful). The meanings of the numeric error
6238 codes are listed in the SRU specification somewhere (no
6239 direct link anymore).
6242 If conversion fails, more information can be obtained by calling
6244 int cql_transform_error(cql_transform_t ct, char **addinfop);
6246 This function returns the most recently returned numeric
6247 error-code and sets the string-pointer at
6248 <literal>*addinfop</literal> to point to a string containing
6249 additional information about the error that occurred: for
6250 example, if the error code is 15 (``Illegal or unsupported context
6251 set''), the additional information is the name of the requested
6252 context set that was not recognised.
6255 The SRU error-codes may be translated into brief human-readable
6256 error messages using
6258 const char *cql_strerror(int code);
6262 If you wish to be able to produce a PQF result in a different
6263 way, there are two alternatives.
6265 void cql_transform_pr(cql_transform_t ct,
6266 struct cql_node *cn,
6267 void (*pr)(const char *buf, void *client_data),
6270 int cql_transform_FILE(cql_transform_t ct,
6271 struct cql_node *cn, FILE *f);
6273 The former function produces output to a user-defined
6274 output stream. The latter writes the result to an already
6275 open <literal>FILE</literal>.
6278 <sect3 id="cql.to.rpn">
6279 <title>Specification of CQL to RPN mappings</title>
6281 The file supplied to functions
6282 <function>cql_transform_open_FILE</function>,
6283 <function>cql_transform_open_fname</function> follows
6284 a structure found in many Unix utilities.
6285 It consists of mapping specifications - one per line.
6286 Lines starting with <literal>#</literal> are ignored (comments).
6289 Each line is of the form
6291 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6295 An RPN pattern is a simple attribute list. Each attribute pair
6298 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6300 The attribute <replaceable>set</replaceable> is optional.
6301 The <replaceable>type</replaceable> is the attribute type,
6302 <replaceable>value</replaceable> the attribute value.
6305 The character <literal>*</literal> (asterisk) has special meaning
6306 when used in the RPN pattern.
6307 Each occurrence of <literal>*</literal> is substituted with the
6308 CQL matching name (index, relation, qualifier etc).
6309 This facility can be used to copy a CQL name verbatim to the RPN result.
6312 The following CQL patterns are recognized:
6316 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6320 This pattern is invoked when a CQL index, such as
6321 dc.title is converted. <replaceable>set</replaceable>
6322 and <replaceable>name</replaceable> are the context set and index
6324 Typically, the RPN specifies an equivalent use attribute.
6327 For terms not bound by an index the pattern
6328 <literal>index.cql.serverChoice</literal> is used.
6329 Here, the prefix <literal>cql</literal> is defined as
6330 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6331 If this pattern is not defined, the mapping will fail.
6335 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6336 is used when no other index pattern is matched.
6342 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6347 For backwards compatibility, this is recognised as a synonym of
6348 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6354 <literal>relation.</literal><replaceable>relation</replaceable>
6358 This pattern specifies how a CQL relation is mapped to RPN.
6359 <replaceable>pattern</replaceable> is name of relation
6360 operator. Since <literal>=</literal> is used as
6361 separator between CQL pattern and RPN, CQL relations
6362 including <literal>=</literal> cannot be
6363 used directly. To avoid a conflict, the names
6364 <literal>ge</literal>,
6365 <literal>eq</literal>,
6366 <literal>le</literal>,
6367 must be used for CQL operators, greater-than-or-equal,
6368 equal, less-than-or-equal respectively.
6369 The RPN pattern is supposed to include a relation attribute.
6372 For terms not bound by a relation, the pattern
6373 <literal>relation.scr</literal> is used. If the pattern
6374 is not defined, the mapping will fail.
6377 The special pattern, <literal>relation.*</literal> is used
6378 when no other relation pattern is matched.
6384 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6388 This pattern specifies how a CQL relation modifier is mapped to RPN.
6389 The RPN pattern is usually a relation attribute.
6395 <literal>structure.</literal><replaceable>type</replaceable>
6399 This pattern specifies how a CQL structure is mapped to RPN.
6400 Note that this CQL pattern is somewhat to similar to
6401 CQL pattern <literal>relation</literal>.
6402 The <replaceable>type</replaceable> is a CQL relation.
6405 The pattern, <literal>structure.*</literal> is used
6406 when no other structure pattern is matched.
6407 Usually, the RPN equivalent specifies a structure attribute.
6413 <literal>position.</literal><replaceable>type</replaceable>
6417 This pattern specifies how the anchor (position) of
6418 CQL is mapped to RPN.
6419 The <replaceable>type</replaceable> is one
6420 of <literal>first</literal>, <literal>any</literal>,
6421 <literal>last</literal>, <literal>firstAndLast</literal>.
6424 The pattern, <literal>position.*</literal> is used
6425 when no other position pattern is matched.
6431 <literal>set.</literal><replaceable>prefix</replaceable>
6435 This specification defines a CQL context set for a given prefix.
6436 The value on the right hand side is the URI for the set -
6437 <emphasis>not</emphasis> RPN. All prefixes used in
6438 index patterns must be defined this way.
6444 <literal>set</literal>
6448 This specification defines a default CQL context set for index names.
6449 The value on the right hand side is the URI for the set.
6455 <example id="example.cql.to.rpn.mapping">
6456 <title>CQL to RPN mapping file</title>
6458 This simple file defines two context sets, three indexes and three
6459 relations, a position pattern and a default structure.
6461 <programlisting><![CDATA[
6462 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6463 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6465 index.cql.serverChoice = 1=1016
6466 index.dc.title = 1=4
6467 index.dc.subject = 1=21
6473 position.any = 3=3 6=1
6479 With the mappings above, the CQL query
6483 is converted to the PQF:
6485 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6487 by rules <literal>index.cql.serverChoice</literal>,
6488 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6489 <literal>position.any</literal>.
6496 is rejected, since <literal>position.right</literal> is
6502 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6506 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6510 <example id="example.cql.to.rpn.string">
6511 <title>CQL to RPN string attributes</title>
6513 In this example we allow any index to be passed to RPN as
6516 <programlisting><![CDATA[
6517 # Identifiers for prefixes used in this file. (index.*)
6518 set.cql = info:srw/cql-context-set/1/cql-v1.1
6519 set.rpn = http://bogus/rpn
6520 set = http://bogus/rpn
6522 # The default index when none is specified by the query
6523 index.cql.serverChoice = 1=any
6532 The <literal>http://bogus/rpn</literal> context set is also the default
6533 so we can make queries such as
6537 which is converted to
6539 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6543 <example id="example.cql.to.rpn.bathprofile">
6544 <title>CQL to RPN using Bath Profile</title>
6546 The file <filename>etc/pqf.properties</filename> has mappings from
6547 the Bath Profile and Dublin Core to RPN.
6548 If YAZ is installed as a package it's usually located
6549 in <filename>/usr/share/yaz/etc</filename> and part of the
6550 development package, such as <literal>libyaz-dev</literal>.
6554 <sect3 id="cql.xcql">
6555 <title>CQL to XCQL conversion</title>
6557 Conversion from CQL to XCQL is trivial and does not
6558 require a mapping to be defined.
6559 There three functions to choose from depending on the
6560 way you wish to store the resulting output (XML buffer
6563 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6564 void cql_to_xml(struct cql_node *cn,
6565 void (*pr)(const char *buf, void *client_data),
6567 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6569 Function <function>cql_to_xml_buf</function> converts
6570 to XCQL and stores result in a user supplied buffer of a given
6574 <function>cql_to_xml</function> writes the result in
6575 a user defined output stream.
6576 <function>cql_to_xml_stdio</function> writes to a
6580 <sect3 id="rpn.to.cql">
6581 <title>PQF to CQL conversion</title>
6583 Conversion from PQF to CQL is offered by the two functions shown
6584 below. The former uses a generic stream for result. The latter
6585 puts result in a WRBUF (string container).
6587 #include <yaz/rpn2cql.h>
6589 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6590 void (*pr)(const char *buf, void *client_data),
6594 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6598 The configuration is the same as used in CQL to PQF conversions.
6603 <sect1 id="tools.oid">
6604 <title>Object Identifiers</title>
6606 The basic YAZ representation of an OID is an array of integers,
6607 terminated with the value -1. This integer is of type
6608 <literal>Odr_oid</literal>.
6611 Fundamental OID operations and the type <literal>Odr_oid</literal>
6612 are defined in <filename>yaz/oid_util.h</filename>.
6615 An OID can either be declared as a automatic variable or it can
6616 allocated using the memory utilities or ODR/NMEM. It's
6617 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6619 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6621 We can create an OID for the Bib-1 attribute set with:
6623 Odr_oid bib1[OID_SIZE];
6635 And OID may also be filled from a string-based representation using
6636 dots (.). This is achieved by function
6638 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6640 This functions returns 0 if name could be converted; -1 otherwise.
6642 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6644 We can fill the Bib-1 attribute set OID easier with:
6646 Odr_oid bib1[OID_SIZE];
6647 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6652 We can also allocate an OID dynamically on a ODR stream with:
6654 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6656 This creates an OID from string-based representation using dots.
6657 This function take an &odr; stream as parameter. This stream is used to
6658 allocate memory for the data elements, which is released on a
6659 subsequent call to <function>odr_reset()</function> on that stream.
6661 <example id="tools.oid.bib1.3">
6662 <title>Using odr_getoidbystr</title>
6664 We can create a OID for the Bib-1 attribute set with:
6666 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6673 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6675 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6676 converts an OID to the string-based representation using dots.
6677 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6678 string and must be at least <literal>OID_STR_MAX</literal> in size.
6681 OIDs can be copied with <function>oid_oidcpy</function> which takes
6682 two OID lists as arguments. Alternativly, an OID copy can be allocated
6683 on a ODR stream with:
6685 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6689 OIDs can be compared with <function>oid_oidcmp</function> which returns
6690 zero if the two OIDs provided are identical; non-zero otherwise.
6692 <sect2 id="tools.oid.database">
6693 <title>OID database</title>
6695 From YAZ version 3 and later, the oident system has been replaced
6696 by an OID database. OID database is a misnomer .. the old odient
6697 system was also a database.
6700 The OID database is really just a map between named Object Identifiers
6701 (string) and their OID raw equivalents. Most operations either
6702 convert from string to OID or other way around.
6705 Unfortunately, whenever we supply a string we must also specify the
6706 <emphasis>OID class</emphasis>. The class is necessary because some
6707 strings correspond to multiple OIDs. An example of such a string is
6708 <literal>Bib-1</literal> which may either be an attribute-set
6709 or a diagnostic-set.
6712 Applications using the YAZ database should include
6713 <filename>yaz/oid_db.h</filename>.
6716 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6717 Actually that's a pointer. You need not think deal with that.
6718 YAZ has a built-in database which can be considered "constant" for
6720 We can get hold that by using function <function>yaz_oid_std</function>.
6723 All functions with prefix <function>yaz_string_to_oid</function>
6724 converts from class + string to OID. We have variants of this
6725 operation due to different memory allocation strategies.
6728 All functions with prefix
6729 <function>yaz_oid_to_string</function> converts from OID to string
6732 <example id="tools.oid.bib1.4">
6733 <title>Create OID with YAZ DB</title>
6735 We can create an OID for the Bib-1 attribute set on the ODR stream
6739 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6741 This is more complex than using <function>odr_getoidbystr</function>.
6742 You would only use <function>yaz_string_to_oid_odr</function> when the
6743 string (here Bib-1) is supplied by a user or configuration.
6747 <sect2 id="tools.oid.std">
6748 <title>Standard OIDs</title>
6750 All the object identifers in the standard OID database as returned
6751 by <function>yaz_oid_std</function> can referenced directly in a
6752 program as a constant OID.
6753 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6754 followed by OID class (lowercase) - then by OID name (normalized and
6758 See <xref linkend="list-oids"/> for list of all object identifiers
6760 These are declared in <filename>yaz/oid_std.h</filename> but are
6761 included by <filename>yaz/oid_db.h</filename> as well.
6763 <example id="tools.oid.bib1.5">
6764 <title>Use a built-in OID</title>
6766 We can allocate our own OID filled with the constant OID for
6769 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6775 <sect1 id="tools.nmem">
6776 <title>Nibble Memory</title>
6778 Sometimes when you need to allocate and construct a large,
6779 interconnected complex of structures, it can be a bit of a pain to
6780 release the associated memory again. For the structures describing the
6781 Z39.50 PDUs and related structures, it is convenient to use the
6782 memory-management system of the &odr; subsystem (see
6783 <xref linkend="odr.use"/>). However, in some circumstances
6784 where you might otherwise benefit from using a simple nibble memory
6785 management system, it may be impractical to use
6786 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6787 For this purpose, the memory manager which also supports the &odr;
6788 streams is made available in the NMEM module. The external interface
6789 to this module is given in the <filename>nmem.h</filename> file.
6792 The following prototypes are given:
6795 NMEM nmem_create(void);
6796 void nmem_destroy(NMEM n);
6797 void *nmem_malloc(NMEM n, size_t size);
6798 void nmem_reset(NMEM n);
6799 size_t nmem_total(NMEM n);
6800 void nmem_init(void);
6801 void nmem_exit(void);
6804 The <function>nmem_create()</function> function returns a pointer to a
6805 memory control handle, which can be released again by
6806 <function>nmem_destroy()</function> when no longer needed.
6807 The function <function>nmem_malloc()</function> allocates a block of
6808 memory of the requested size. A call to <function>nmem_reset()</function>
6809 or <function>nmem_destroy()</function> will release all memory allocated
6810 on the handle since it was created (or since the last call to
6811 <function>nmem_reset()</function>. The function
6812 <function>nmem_total()</function> returns the number of bytes currently
6813 allocated on the handle.
6816 The nibble memory pool is shared amongst threads. POSIX
6817 mutex'es and WIN32 Critical sections are introduced to keep the
6818 module thread safe. Function <function>nmem_init()</function>
6819 initializes the nibble memory library and it is called automatically
6820 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6821 function <function>DllMain</function> to achieve this. You should
6822 <emphasis>not</emphasis> call <function>nmem_init</function> or
6823 <function>nmem_exit</function> unless you're absolute sure what
6824 you're doing. Note that in previous &yaz; versions you'd have to call
6825 <function>nmem_init</function> yourself.
6828 <sect1 id="tools.log">
6831 &yaz; has evolved a fairly complex log system which should be useful both
6832 for debugging &yaz; itself, debugging applications that use &yaz;, and for
6833 production use of those applications.
6836 The log functions are declared in header <filename>yaz/log.h</filename>
6837 and implemented in <filename>src/log.c</filename>.
6838 Due to name clash with syslog and some math utilities the logging
6839 interface has been modified as of YAZ 2.0.29. The obsolete interface
6840 is still available if in header file <filename>yaz/log.h</filename>.
6841 The key points of the interface are:
6844 void yaz_log(int level, const char *fmt, ...)
6845 void yaz_log_init(int level, const char *prefix, const char *name);
6846 void yaz_log_init_file(const char *fname);
6847 void yaz_log_init_level(int level);
6848 void yaz_log_init_prefix(const char *prefix);
6849 void yaz_log_time_format(const char *fmt);
6850 void yaz_log_init_max_size(int mx);
6852 int yaz_log_mask_str(const char *str);
6853 int yaz_log_module_level(const char *name);
6856 The reason for the whole log module is the <function>yaz_log</function>
6857 function. It takes a bitmask indicating the log levels, a
6858 <literal>printf</literal>-like format string, and a variable number of
6862 The <literal>log level</literal> is a bit mask, that says on which level(s)
6863 the log entry should be made, and optionally set some behaviour of the
6864 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
6865 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
6866 that modify the way the log entry is written:<literal>YLOG_ERRNO,
6867 YLOG_NOTIME, YLOG_FLUSH</literal>.
6868 Most of the rest of the bits are deprecated, and should not be used. Use
6869 the dynamic log levels instead.
6872 Applications that use &yaz;, should not use the LOG_LOG for ordinary
6873 messages, but should make use of the dynamic loglevel system. This consists
6874 of two parts, defining the loglevel and checking it.
6877 To define the log levels, the (main) program should pass a string to
6878 <function>yaz_log_mask_str</function> to define which log levels are to be
6879 logged. This string should be a comma-separated list of log level names,
6880 and can contain both hard-coded names and dynamic ones. The log level
6881 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
6882 for each word it meets, unless the word starts with a '-', in which case it
6883 clears the bit. If the string <literal>'none'</literal> is found,
6884 all bits are cleared. Typically this string comes from the command-line,
6885 often identified by <literal>-v</literal>. The
6886 <function>yaz_log_mask_str</function> returns a log level that should be
6887 passed to <function>yaz_log_init_level</function> for it to take effect.
6890 Each module should check what log bits it should be used, by calling
6891 <function>yaz_log_module_level</function> with a suitable name for the
6892 module. The name is cleared from a preceding path and an extension, if any,
6893 so it is quite possible to use <literal>__FILE__</literal> for it. If the
6894 name has been passed to <function>yaz_log_mask_str</function>, the routine
6895 returns a non-zero bitmask, which should then be used in consequent calls
6896 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
6897 yaz_log, in time-critical places, or when the log entry would take time
6901 Yaz uses the following dynamic log levels:
6902 <literal>server, session, request, requestdetail</literal> for the server
6904 <literal>zoom</literal> for the zoom client api.
6905 <literal>ztest</literal> for the simple test server.
6906 <literal>malloc, nmem, odr, eventl</literal> for internal
6907 debugging of yaz itself.
6908 Of course, any program using yaz is welcome to define as many new
6912 By default the log is written to stderr, but this can be changed by a call
6913 to <function>yaz_log_init_file</function> or
6914 <function>yaz_log_init</function>. If the log is directed to a file, the
6915 file size is checked at every write, and if it exceeds the limit given in
6916 <function>yaz_log_init_max_size</function>, the log is rotated. The
6917 rotation keeps one old version (with a <literal>.1</literal> appended to
6918 the name). The size defaults to 1GB. Setting it to zero will disable the
6922 A typical yaz-log looks like this
6923 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
6924 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
6925 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
6926 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
6927 13:24:13-23/11 yaz-ztest(1) [request] Close OK
6930 The log entries start with a time stamp. This can be omitted by setting the
6931 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
6932 can be hoped to produce identical log files, that are easy to diff. The
6933 format of the time stamp can be set with
6934 <function>yaz_log_time_format</function>, which takes a format string just
6935 like <function>strftime</function>.
6938 Next in a log line comes the prefix, often the name of the program. For
6939 yaz-based servers, it can also contain the session number. Then
6940 comes one or more logbits in square brackets, depending on the logging
6941 level set by <function>yaz_log_init_level</function> and the loglevel
6942 passed to <function>yaz_log_init_level</function>. Finally comes the format
6943 string and additional values passed to <function>yaz_log</function>
6946 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
6947 <literal>loglevel</literal>, will log all the log-level affecting
6948 operations. This can come in handy if you need to know what other log
6949 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
6952 The log system is almost independent of the rest of &yaz;, the only
6953 important dependence is of <filename>nmem</filename>, and that only for
6954 using the semaphore definition there.
6957 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
6958 the same time, the log bit names were changed from
6959 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
6960 to avoid collision with <filename>syslog.h</filename>.
6966 YAZ provides a fast utility for working with MARC records.
6967 Early versions of the MARC utility only allowed decoding of ISO2709.
6968 Today the utility may both encode - and decode to a varity of formats.
6971 #include <yaz/marcdisp.h>
6973 /* create handler */
6974 yaz_marc_t yaz_marc_create(void);
6976 void yaz_marc_destroy(yaz_marc_t mt);
6978 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
6979 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
6980 #define YAZ_MARC_LINE 0
6981 #define YAZ_MARC_SIMPLEXML 1
6982 #define YAZ_MARC_OAIMARC 2
6983 #define YAZ_MARC_MARCXML 3
6984 #define YAZ_MARC_ISO2709 4
6985 #define YAZ_MARC_XCHANGE 5
6986 #define YAZ_MARC_CHECK 6
6987 #define YAZ_MARC_TURBOMARC 7
6988 #define YAZ_MARC_JSON 8
6990 /* supply iconv handle for character set conversion .. */
6991 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
6993 /* set debug level, 0=none, 1=more, 2=even more, .. */
6994 void yaz_marc_debug(yaz_marc_t mt, int level);
6996 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
6997 On success, result in *result with size *rsize. */
6998 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
6999 const char **result, size_t *rsize);
7001 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7002 On success, result in WRBUF */
7003 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7004 int bsize, WRBUF wrbuf);
7009 The synopsis is just a basic subset of all functionality. Refer
7010 to the actual header file <filename>marcdisp.h</filename> for
7015 A MARC conversion handle must be created by using
7016 <function>yaz_marc_create</function> and destroyed
7017 by calling <function>yaz_marc_destroy</function>.
7020 All other function operate on a <literal>yaz_marc_t</literal> handle.
7021 The output is specified by a call to <function>yaz_marc_xml</function>.
7022 The <literal>xmlmode</literal> must be one of
7025 <term>YAZ_MARC_LINE</term>
7028 A simple line-by-line format suitable for display but not
7029 recommend for further (machine) processing.
7034 <term>YAZ_MARC_MARCXML</term>
7037 <ulink url="&url.marcxml;">MARCXML</ulink>.
7042 <term>YAZ_MARC_ISO2709</term>
7045 ISO2709 (sometimes just referred to as "MARC").
7050 <term>YAZ_MARC_XCHANGE</term>
7053 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7058 <term>YAZ_MARC_CHECK</term>
7061 Pseudo format for validation only. Does not generate
7062 any real output except diagnostics.
7067 <term>YAZ_MARC_TURBOMARC</term>
7070 XML format with same semantics as MARCXML but more compact
7071 and geared towards fast processing with XSLT. Refer to
7072 <xref linkend="tools.turbomarc"/> for more information.
7077 <term>YAZ_MARC_JSON</term>
7080 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7087 The actual conversion functions are
7088 <function>yaz_marc_decode_buf</function> and
7089 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7090 a MARC record. The former function operates on simple buffers, the
7091 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7094 <example id="example.marc.display">
7095 <title>Display of MARC record</title>
7097 The following program snippet illustrates how the MARC API may
7098 be used to convert a MARC record to the line-by-line format:
7099 <programlisting><![CDATA[
7100 void print_marc(const char *marc_buf, int marc_buf_size)
7102 char *result; /* for result buf */
7103 size_t result_len; /* for size of result */
7104 yaz_marc_t mt = yaz_marc_create();
7105 yaz_marc_xml(mt, YAZ_MARC_LINE);
7106 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7107 &result, &result_len);
7108 fwrite(result, result_len, 1, stdout);
7109 yaz_marc_destroy(mt); /* note that result is now freed... */
7115 <sect2 id="tools.turbomarc">
7116 <title>TurboMARC</title>
7118 TurboMARC is yet another XML encoding of a MARC record. The format
7119 was designed for fast processing with XSLT.
7123 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7124 representation. This conversion mostly check the tag of a MARC field
7125 to determine the basic rules in the conversion. This check is
7126 costly when that is tag is encoded as an attribute in MARCXML.
7127 By having the tag value as the element instead, makes processing
7128 many times faster (at least for Libxslt).
7131 TurboMARC is encoded as follows:
7135 Record elements is part of namespace
7136 "<literal>http://www.indexdata.com/turbomarc</literal>".
7141 A record is enclosed in element <literal>r</literal>.
7146 A collection of records is enclosed in element
7147 <literal>collection</literal>.
7152 The leader is encoded as element <literal>l</literal> with the
7153 leader content as its (text) value.
7158 A control field is encoded as element <literal>c</literal> concatenated
7159 with the tag value of the control field if the tag value
7160 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7161 If the tag value do not match the regular expression
7162 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7163 as element <literal>c</literal> and attribute <literal>code</literal>
7164 will hold the tag value.
7165 This rule ensure that in the rare cases where a tag value might
7166 result in a non-wellformed XML YAZ encode it as a coded attribute
7170 The control field content is the the text value of this element.
7171 Indicators are encoded as attribute names
7172 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7173 corresponding values for each indicator.
7178 A data field is encoded as element <literal>d</literal> concatenated
7179 with the tag value of the data field or using the attribute
7180 <literal>code</literal> as described in the rules for control fields.
7181 The children of the data field element is subfield elements.
7182 Each subfield element is encoded as <literal>s</literal>
7183 concatenated with the sub field code.
7184 The text of the subfield element is the contents of the subfield.
7185 Indicators are encoded as attributes for the data field element similar
7186 to the encoding for control fields.
7193 <sect1 id="tools.retrieval">
7194 <title>Retrieval Facility</title>
7196 YAZ version 2.1.20 or later includes a Retrieval facility tool
7197 which allows a SRU/Z39.50 to describe itself and perform record
7198 conversions. The idea is the following:
7202 An SRU/Z39.50 client sends a retrieval request which includes
7203 a combination of the following parameters: syntax (format),
7204 schema (or element set name).
7209 The retrieval facility is invoked with parameters in a
7210 server/proxy. The retrieval facility matches the parameters a set of
7211 "supported" retrieval types.
7212 If there is no match, the retrieval signals an error
7213 (syntax and / or schema not supported).
7218 For a successful match, the backend is invoked with the same
7219 or altered retrieval parameters (syntax, schema). If
7220 a record is received from the backend, it is converted to the
7221 frontend name / syntax.
7226 The resulting record is sent back the client and tagged with
7227 the frontend syntax / schema.
7233 The Retrieval facility is driven by an XML configuration. The
7234 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7235 should be easy to generate both of them from the XML configuration.
7236 (unfortunately the two versions
7237 of ZeeRex differ substantially in this regard).
7239 <sect2 id="tools.retrieval.format">
7240 <title>Retrieval XML format</title>
7242 All elements should be covered by namespace
7243 <literal>http://indexdata.com/yaz</literal> .
7244 The root element node must be <literal>retrievalinfo</literal>.
7247 The <literal>retrievalinfo</literal> must include one or
7248 more <literal>retrieval</literal> elements. Each
7249 <literal>retrieval</literal> defines specific combination of
7250 syntax, name and identifier supported by this retrieval service.
7253 The <literal>retrieval</literal> element may include any of the
7254 following attributes:
7256 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7259 Defines the record syntax. Possible values is any
7260 of the names defined in YAZ' OID database or a raw
7265 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7268 Defines the name of the retrieval format. This can be
7269 any string. For SRU, the value, is equivalent to schema (short-hand);
7270 for Z39.50 it's equivalent to simple element set name.
7271 For YAZ 3.0.24 and later this name may be specified as a glob
7272 expression with operators
7273 <literal>*</literal> and <literal>?</literal>.
7277 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7280 Defines the URI schema name of the retrieval format. This can be
7281 any string. For SRU, the value, is equivalent to URI schema.
7282 For Z39.50, there is no equivalent.
7289 The <literal>retrieval</literal> may include one
7290 <literal>backend</literal> element. If a <literal>backend</literal>
7291 element is given, it specifies how the records are retrieved by
7292 some backend and how the records are converted from the backend to
7296 The attributes, <literal>name</literal> and <literal>syntax</literal>
7297 may be specified for the <literal>backend</literal> element. These
7298 semantics of these attributes is equivalent to those for the
7299 <literal>retrieval</literal>. However, these values are passed to
7303 The <literal>backend</literal> element may includes one or more
7304 conversion instructions (as children elements). The supported
7307 <varlistentry><term><literal>marc</literal></term>
7310 The <literal>marc</literal> element specifies a conversion
7311 to - and from ISO2709 encoded MARC and
7312 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7313 The following attributes may be specified:
7316 <term><literal>inputformat</literal> (REQUIRED)</term>
7319 Format of input. Supported values are
7320 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7321 (MARCXML/MarcXchange) and <literal>json</literal>
7322 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7327 <term><literal>outputformat</literal> (REQUIRED)</term>
7330 Format of output. Supported values are
7331 <literal>line</literal> (MARC line format);
7332 <literal>marcxml</literal> (for MARCXML),
7333 <literal>marc</literal> (ISO2709),
7334 <literal>marcxhcange</literal> (for MarcXchange),
7335 or <literal>json</literal>
7336 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7341 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7344 Encoding of input. For XML input formats, this need not
7345 be given, but for ISO2709 based inputformats, this should
7346 be set to the encoding used. For MARC21 records, a common
7347 inputcharset value would be <literal>marc-8</literal>.
7352 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7355 Encoding of output. If outputformat is XML based, it is
7356 strongly recommened to use <literal>utf-8</literal>.
7365 <term><literal>xslt</literal></term>
7368 The <literal>xslt</literal> element specifies a conversion
7369 via &acro.xslt;. The following attributes may be specified:
7371 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7383 <term><literal>solrmarc</literal></term>
7386 The <literal>solrmarc</literal> decodes solrmarc records.
7387 It assumes that the input is pure solrmarc text (no escaping)
7388 and will convert all sequences of the form #XX; to a single
7389 character of the hexadecimal value as given by XX. The output,
7390 presumably, is a valid ISO2709 buffer.
7393 This conversion is available in YAZ 5.0.21 and later.
7400 <sect2 id="tools.retrieval.examples">
7401 <title>Retrieval Facility Examples</title>
7402 <example id="tools.retrieval.marc21">
7403 <title>MARC21 backend</title>
7405 A typical way to use the retrieval facility is to enable XML
7406 for servers that only supports ISO2709 encoded MARC21 records.
7408 <programlisting><![CDATA[
7410 <retrieval syntax="usmarc" name="F"/>
7411 <retrieval syntax="usmarc" name="B"/>
7412 <retrieval syntax="xml" name="marcxml"
7413 identifier="info:srw/schema/1/marcxml-v1.1">
7414 <backend syntax="usmarc" name="F">
7415 <marc inputformat="marc" outputformat="marcxml"
7416 inputcharset="marc-8"/>
7419 <retrieval syntax="xml" name="dc">
7420 <backend syntax="usmarc" name="F">
7421 <marc inputformat="marc" outputformat="marcxml"
7422 inputcharset="marc-8"/>
7423 <xslt stylesheet="MARC21slim2DC.xsl"/>
7430 This means that our frontend supports:
7434 MARC21 F(ull) records.
7439 MARC21 B(rief) records.
7449 Dublin core records.
7455 <example id="tools.retrieval.marcxml">
7456 <title>MARCXML backend</title>
7458 SRW/SRU and Solr backends returns records in XML.
7459 If they return MARCXML or MarcXchange, the retrieval module
7460 can convert those into ISO2709 formats, most commonly USMARC
7462 In this example, the backend returns MARCXML for schema="marcxml".
7464 <programlisting><![CDATA[
7466 <retrieval syntax="usmarc">
7467 <backend syntax="xml" name="marcxml">
7468 <marc inputformat="xml" outputformat="marc"
7469 outputcharset="marc-8"/>
7472 <retrieval syntax="xml" name="marcxml"
7473 identifier="info:srw/schema/1/marcxml-v1.1"/>
7474 <retrieval syntax="xml" name="dc">
7475 <backend syntax="xml" name="marcxml">
7476 <xslt stylesheet="MARC21slim2DC.xsl"/>
7483 This means that our frontend supports:
7487 MARC21 records (any element set name) in MARC-8 encoding.
7492 MARCXML records for element-set=marcxml
7497 Dublin core records for element-set=dc.
7504 <sect2 id="tools.retrieval.api">
7507 It should be easy to use the retrieval systems from applications. Refer
7509 <filename>yaz/retrieval.h</filename> and
7510 <filename>yaz/record_conv.h</filename>.
7514 <sect1 id="sorting">
7515 <title>Sorting</title>
7517 This chapter describes sorting and how it is supported in YAZ.
7518 Sorting applies to a result-set.
7520 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7521 Z39.50 sorting facility
7523 takes one or more input result-sets
7524 and one result-set as output. The most simple case is that
7525 the input-set is the same as the output-set.
7528 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7529 following a search (two phases).
7532 In SRU/Solr, however, the model is different. Here, sorting is specified
7533 during the the search operation. Note, however, that SRU might
7534 perform sort as separate search, by referring to an existing result-set
7535 in the query (result-set reference).
7538 <title>Using the Z39.50 sort service</title>
7540 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7541 case the sort sequence or sort critiera is using a string notation.
7542 This notation is a one-line notation suitable for being manually
7543 entered or generated and allows for easy logging (one liner).
7544 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7545 function. For yaz-client the sort is performed and specified using
7546 the sort and sort+ commands. For description of the sort criteria notation
7547 refer to the <link linkend="sortspec">sort command</link> in the
7551 The ZOOM API might choose one of several sort strategies for
7552 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7556 <title>Type-7 sort</title>
7558 Type-7 sort is an extension to the Bib-1 based RPN query where the
7559 sort specification is embedded as an Attribute-Plus-Term.
7562 The objectives for introducing Type-7 sorting is that it allows
7563 a client to perform sorting even if it does not implement/support
7564 Z39.50 sort. Virtually all Z39.50 client software supports
7565 RPN queries. It also may improve performance because the sort
7566 critieria is specified along with the search query.
7569 The sort is triggered by the presence of type 7 and the value of type 7
7571 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7574 The value for type 7 is 1 for ascending and 2 for descending.
7576 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7579 only the generic part is handled. If generic sortKey is of type
7580 sortField, then attribute type 1 is present and the value is
7581 sortField (InternationalString). If generic sortKey is of type
7582 sortAttributes, then the attributes in list is used . generic sortKey
7583 of type elementSpec is not supported.
7586 The term in the sorting Attribute-Plus-Term combo should hold
7587 an integer. The value is 0 for primary sorting criteria, 1 for second
7593 <title>Facets</title>
7595 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7598 Like Type-1/RPN, YAZ supports a string notation for specifying
7599 facets. For the API this is performed by
7600 <function>yaz_pqf_parse_facet_list</function>.
7603 For ZOOM C the facets are given by option "facets"
7604 For yaz-client it is used for the facets command.
7607 The grammar of this specification is as follows:
7609 facet-spec ::= facet-list
7611 facet-list ::= facet-list ',' attr-spec | attr-spec
7613 attr-spec ::= attr-spec '@attr' string | '@attr' string
7616 The notation is inspired by PQF. The string following '@attr'
7617 may not include blanks and is of the form
7618 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7619 where <replaceable>type</replaceable> is an integer and
7620 <replaceable>value</replaceable> is a string or an integer.
7623 The Facets specification is not Bib-1. The following types apply:
7625 <table id="facet.attributes">
7626 <title>Facet attributes</title>
7628 <colspec colwidth="2*" colname="type"></colspec>
7629 <colspec colwidth="9*" colname="description"></colspec>
7633 <entry>Description</entry>
7640 Field-name. This is often a string, eg "Author", "Year", etc.
7646 Sort order. Value should be an integer.
7647 Value 0: count descending (frequency). Value 1: alpha ascending.
7653 Number of terms requested.
7668 <title>The ODR Module</title>
7669 <sect1 id="odr.introduction">
7670 <title>Introduction</title>
7672 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7673 to isolate &odr; from the rest of the package - specifically from the
7674 transport interface. &odr; may be used in any context where basic
7675 ASN.1/BER representations are used.
7678 If you are only interested in writing a Z39.50 implementation based on
7679 the PDUs that are already provided with &yaz;, you only need to concern
7680 yourself with the section on managing ODR streams
7681 (<xref linkend="odr.use"/>). Only if you need to
7682 implement ASN.1 beyond that which has been provided, should you
7683 worry about the second half of the documentation
7684 (<xref linkend="odr.programming"/>).
7685 If you use one of the higher-level interfaces, you can skip this
7689 This is important, so we'll repeat it for emphasis: <emphasis>You do
7690 not need to read <xref linkend="odr.programming"/>
7691 to implement Z39.50 with &yaz;.</emphasis>
7694 If you need a part of the protocol that isn't already in &yaz;, you
7695 should contact the authors before going to work on it yourself: We
7696 might already be working on it. Conversely, if you implement a useful
7697 part of the protocol before us, we'd be happy to include it in a
7701 <sect1 id="odr.use">
7702 <title>Using ODR</title>
7703 <sect2 id="odr.streams">
7704 <title>ODR Streams</title>
7706 Conceptually, the ODR stream is the source of encoded data in the
7707 decoding mode; when encoding, it is the receptacle for the encoded
7708 data. Before you can use an ODR stream it must be allocated. This is
7709 done with the function
7712 ODR odr_createmem(int direction);
7715 The <function>odr_createmem()</function> function takes as argument one
7716 of three manifest constants: <literal>ODR_ENCODE</literal>,
7717 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7718 An &odr; stream can be in only one mode - it is not possible to change
7719 its mode once it's selected. Typically, your program will allocate
7720 at least two ODR streams - one for decoding, and one for encoding.
7723 When you're done with the stream, you can use
7726 void odr_destroy(ODR o);
7729 to release the resources allocated for the stream.
7732 <sect2 id="odr.memory.management">
7733 <title id="memory">Memory Management</title>
7735 Two forms of memory management take place in the &odr; system. The first
7736 one, which has to do with allocating little bits of memory (sometimes
7737 quite large bits of memory, actually) when a protocol package is
7738 decoded, and turned into a complex of interlinked structures. This
7739 section deals with this system, and how you can use it for your own
7740 purposes. The next section deals with the memory management which is
7741 required when encoding data - to make sure that a large enough buffer is
7742 available to hold the fully encoded PDU.
7745 The &odr; module has its own memory management system, which is
7746 used whenever memory is required. Specifically, it is used to allocate
7747 space for data when decoding incoming PDUs. You can use the memory
7748 system for your own purposes, by using the function
7751 void *odr_malloc(ODR o, size_t size);
7754 You can't use the normal <function>free(2)</function> routine to free
7755 memory allocated by this function, and &odr; doesn't provide a parallel
7756 function. Instead, you can call
7759 void odr_reset(ODR o);
7762 when you are done with the
7763 memory: Everything allocated since the last call to
7764 <function>odr_reset()</function> is released.
7765 The <function>odr_reset()</function> call is also required to clear
7766 up an error condition on a stream.
7772 size_t odr_total(ODR o);
7775 returns the number of bytes allocated on the stream since the last call to
7776 <function>odr_reset()</function>.
7779 The memory subsystem of &odr; is fairly efficient at allocating and
7780 releasing little bits of memory. Rather than managing the individual,
7781 small bits of space, the system maintains a free-list of larger chunks
7782 of memory, which are handed out in small bits. This scheme is
7783 generally known as a <emphasis>nibble memory</emphasis> system.
7784 It is very useful for maintaining short-lived constructions such
7788 If you want to retain a bit of memory beyond the next call to
7789 <function>odr_reset()</function>, you can use the function
7792 ODR_MEM odr_extract_mem(ODR o);
7795 This function will give you control of the memory recently allocated
7796 on the ODR stream. The memory will live (past calls to
7797 <function>odr_reset()</function>), until you call the function
7800 void odr_release_mem(ODR_MEM p);
7803 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
7804 referencing the memory block for you until you want to release it.
7807 You can use <function>odr_extract_mem()</function> repeatedly between
7808 allocating data, to retain individual control of separate chunks of data.
7811 <sect2 id="odr.encoding.and.decoding">
7812 <title>Encoding and Decoding Data</title>
7814 When encoding data, the ODR stream will write the encoded octet string
7815 in an internal buffer. To retrieve the data, use the function
7818 char *odr_getbuf(ODR o, int *len, int *size);
7821 The integer pointed to by len is set to the length of the encoded
7822 data, and a pointer to that data is returned. <literal>*size</literal>
7823 is set to the size of the buffer (unless <literal>size</literal> is null,
7824 signaling that you are not interested in the size). The next call to
7825 a primitive function using the same &odr; stream will overwrite the
7826 data, unless a different buffer has been supplied using the call
7829 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
7832 which sets the encoding (or decoding) buffer used by
7833 <literal>o</literal> to <literal>buf</literal>, using the length
7834 <literal>len</literal>.
7835 Before a call to an encoding function, you can use
7836 <function>odr_setbuf()</function> to provide the stream with an encoding
7837 buffer of sufficient size (length). The <literal>can_grow</literal>
7838 parameter tells the encoding &odr; stream whether it is allowed to use
7839 <function>realloc(2)</function> to increase the size of the buffer when
7840 necessary. The default condition of a new encoding stream is equivalent
7841 to the results of calling
7844 odr_setbuf(stream, 0, 0, 1);
7847 In this case, the stream will allocate and reallocate memory as
7848 necessary. The stream reallocates memory by repeatedly doubling the
7849 size of the buffer - the result is that the buffer will typically
7850 reach its maximum, working size with only a small number of reallocation
7851 operations. The memory is freed by the stream when the latter is destroyed,
7852 unless it was assigned by the user with the <literal>can_grow</literal>
7853 parameter set to zero (in this case, you are expected to retain
7854 control of the memory yourself).
7857 To assume full control of an encoded buffer, you must first call
7858 <function>odr_getbuf()</function> to fetch the buffer and its length.
7859 Next, you should call <function>odr_setbuf()</function> to provide a
7860 different buffer (or a null pointer) to the stream. In the simplest
7861 case, you will reuse the same buffer over and over again, and you
7862 will just need to call <function>odr_getbuf()</function> after each
7863 encoding operation to get the length and address of the buffer.
7864 Note that the stream may reallocate the buffer during an encoding
7865 operation, so it is necessary to retrieve the correct address after
7866 each encoding operation.
7869 It is important to realize that the ODR stream will not release this
7870 memory when you call <function>odr_reset()</function>: It will
7871 merely update its internal pointers to prepare for the encoding of a
7873 When the stream is released by the <function>odr_destroy()</function>
7874 function, the memory given to it by <function>odr_setbuf</function> will
7875 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
7876 parameter to <function>odr_setbuf()</function> was nonzero. The
7877 <literal>can_grow</literal> parameter, in other words, is a way of
7878 signaling who is to own the buffer, you or the ODR stream. If you never call
7879 <function>odr_setbuf()</function> on your encoding stream, which is
7880 typically the case, the buffer allocated by the stream will belong to
7881 the stream by default.
7884 When you wish to decode data, you should first call
7885 <function>odr_setbuf()</function>, to tell the decoding stream
7886 where to find the encoded data, and how long the buffer is
7887 (the <literal>can_grow</literal> parameter is ignored by a decoding
7888 stream). After this, you can call the function corresponding to the
7889 data you wish to decode (eg, <function>odr_integer()</function> odr
7890 <function>z_APDU()</function>).
7892 <example id="example.odr.encoding.and.decoding.functions">
7893 <title>Encoding and decoding functions</title>
7895 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
7897 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
7901 If the data is absent (or doesn't match the tag corresponding to
7902 the type), the return value will be either 0 or 1 depending on the
7903 <literal>optional</literal> flag. If <literal>optional</literal>
7904 is 0 and the data is absent, an error flag will be raised in the
7905 stream, and you'll need to call <function>odr_reset()</function> before
7906 you can use the stream again. If <literal>optional</literal> is
7907 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
7908 <literal>p</literal> will be set to the null value, and the function
7910 The <literal>name</literal> argument is used to pretty-print the
7911 tag in question. It may be set to <literal>NULL</literal> if
7912 pretty-printing is not desired.
7915 If the data value is found where it's expected, the pointer
7916 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
7917 will be set to point to the decoded type.
7918 The space for the type will be allocated and owned by the &odr;
7919 stream, and it will live until you call
7920 <function>odr_reset()</function> on the stream. You cannot use
7921 <function>free(2)</function> to release the memory.
7922 You can decode several data elements (by repeated calls to
7923 <function>odr_setbuf()</function> and your decoding function), and
7924 new memory will be allocated each time. When you do call
7925 <function>odr_reset()</function>, everything decoded since the
7926 last call to <function>odr_reset()</function> will be released.
7928 <example id="example.odr.encoding.of.integer">
7929 <title>Encoding and decoding of an integer</title>
7931 The use of the double indirection can be a little confusing at first
7932 (its purpose will become clear later on, hopefully),
7933 so an example is in order. We'll encode an integer value, and
7934 immediately decode it again using a different stream. A useless, but
7935 informative operation.
7937 <programlisting><![CDATA[
7938 void do_nothing_useful(Odr_int value)
7941 Odr_int *valp, *resvalp;
7945 /* allocate streams */
7946 if (!(encode = odr_createmem(ODR_ENCODE)))
7948 if (!(decode = odr_createmem(ODR_DECODE)))
7952 if (odr_integer(encode, &valp, 0, 0) == 0)
7954 printf("encoding went bad\n");
7957 bufferp = odr_getbuf(encode, &len, 0);
7958 printf("length of encoded data is %d\n", len);
7960 /* now let's decode the thing again */
7961 odr_setbuf(decode, bufferp, len, 0);
7962 if (odr_integer(decode, &resvalp, 0, 0) == 0)
7964 printf("decoding went bad\n");
7967 /* ODR_INT_PRINTF format for printf (such as %d) */
7968 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
7971 odr_destroy(encode);
7972 odr_destroy(decode);
7977 This looks like a lot of work, offhand. In practice, the &odr; streams
7978 will typically be allocated once, in the beginning of your program
7979 (or at the beginning of a new network session), and the encoding
7980 and decoding will only take place in a few, isolated places in your
7981 program, so the overhead is quite manageable.
7985 <sect2 id="odr.printing">
7986 <title>Printing</title>
7988 When an ODR stream is created of type <literal>ODR_PRINT</literal>
7989 the ODR module will print the contents of a PDU in a readable format.
7990 By default output is written to the <literal>stderr</literal> stream.
7991 This behavior can be changed, however, by calling the function
7993 odr_setprint(ODR o, FILE *file);
7995 before encoders or decoders are being invoked.
7996 It is also possible to direct the output to a buffer (of indeed
7997 another file), by using the more generic mechanism:
7999 void odr_set_stream(ODR o, void *handle,
8000 void (*stream_write)(ODR o, void *handle, int type,
8001 const char *buf, int len),
8002 void (*stream_close)(void *handle));
8004 Here the user provides an opaque handle and two handlers,
8005 <replaceable>stream_write</replaceable> for writing,
8006 and <replaceable>stream_close</replaceable> which is supposed
8007 to close/free resources associated with handle.
8008 The <replaceable>stream_close</replaceable> handler is optional and
8009 if NULL for the function is provided, it will not be invoked.
8010 The <replaceable>stream_write</replaceable> takes the ODR handle
8011 as parameter, the user defined handle, a type
8012 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8013 which indicates the type of contents is being written.
8016 Another utility useful for diagnostics (error handling) or as
8017 part of the printing facilities is:
8019 const char **odr_get_element_path(ODR o);
8021 which returns a list of current elements that ODR deals with at the
8022 moment. For the returned array, say <literal>ar</literal>,
8023 <literal>ar[0]</literal> is the top level element,
8024 <literal>ar[n]</literal> is the last. The last element has the
8025 property that <literal>ar[n+1] == NULL</literal>.
8027 <example id="example.odr.element.path.record">
8028 <title>Element Path for record</title>
8030 For a database record part of a PresentResponse the
8031 array returned by <function>odr_get_element</function>
8032 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8033 unnamed constructions.
8037 <sect2 id="odr.diagnostics">
8038 <title>Diagnostics</title>
8040 The encoding/decoding functions all return 0 when an error occurs.
8041 Until you call <function>odr_reset()</function>, you cannot use the
8042 stream again, and any function called will immediately return 0.
8045 To provide information to the programmer or administrator, the function
8048 void odr_perror(ODR o, char *message);
8051 is provided, which prints the <literal>message</literal> argument to
8052 <literal>stderr</literal> along with an error message from the stream.
8055 You can also use the function
8058 int odr_geterror(ODR o);
8061 to get the current error number from the screen. The number will be
8062 one of these constants:
8064 <table frame="top" id="odr.error.codes">
8065 <title>ODR Error codes</title>
8070 <entry>Description</entry>
8075 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8078 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8079 The standard diagnostic variable <literal>errno</literal> should be
8080 examined to determine the actual error.</entry>
8083 <entry>OSPACE</entry><entry>No more space for encoding.
8084 This will only occur when the user has explicitly provided a
8085 buffer for an encoding stream without allowing the system to
8086 allocate more space.</entry>
8089 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8090 required data element was missing during encoding or decoding.</entry>
8093 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8094 found during decoding.</entry>
8097 <entry>OOTHER</entry><entry>Other error. This is typically an
8098 indication of misuse of the &odr; system by the programmer, and also
8099 that the diagnostic system isn't as good as it should be, yet.</entry>
8105 The character string array
8111 can be indexed by the error code to obtain a human-readable
8112 representation of the problem.
8115 <sect2 id="odr.summary.and.synopsis">
8116 <title>Summary and Synopsis</title>
8118 #include <yaz/odr.h>
8120 ODR odr_createmem(int direction);
8122 void odr_destroy(ODR o);
8124 void odr_reset(ODR o);
8126 char *odr_getbuf(ODR o, int *len, int *size);
8128 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8130 void *odr_malloc(ODR o, int size);
8132 NMEM odr_extract_mem(ODR o);
8134 int odr_geterror(ODR o);
8136 void odr_perror(ODR o, const char *message);
8138 extern char *odr_errlist[];
8142 <sect1 id="odr.programming">
8143 <title>Programming with ODR</title>
8145 The API of &odr; is designed to reflect the structure of ASN.1, rather
8146 than BER itself. Future releases may be able to represent data in
8147 other external forms.
8151 There is an ASN.1 tutorial available at
8152 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8153 This site also has standards for ASN.1 (X.680) and BER (X.690)
8154 <ulink url="&url.asn.1.standards;">online</ulink>.
8158 The ODR interface is based loosely on that of the Sun Microsystems
8160 Specifically, each function which corresponds to an ASN.1 primitive
8161 type has a dual function. Depending on the settings of the ODR
8162 stream which is supplied as a parameter, the function may be used
8163 either to encode or decode data. The functions that can be built
8164 using these primitive functions, to represent more complex data types,
8165 share this quality. The result is that you only have to enter the
8166 definition for a type once - and you have the functionality of encoding,
8167 decoding (and pretty-printing) all in one unit.
8168 The resulting C source code is quite compact, and is a pretty
8169 straightforward representation of the source ASN.1 specification.
8172 In many cases, the model of the XDR functions works quite well in this
8174 In others, it is less elegant. Most of the hassle comes from the optional
8175 SEQUENCE members which don't exist in XDR.
8177 <sect2 id="odr.primitive.asn1.types">
8178 <title>The Primitive ASN.1 Types</title>
8180 ASN.1 defines a number of primitive types (many of which correspond
8181 roughly to primitive types in structured programming languages, such as C).
8183 <sect3 id="odr.integer">
8184 <title>INTEGER</title>
8186 The &odr; function for encoding or decoding (or printing) the ASN.1
8187 INTEGER type looks like this:
8190 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8193 The <literal>Odr_int</literal> is just a simple integer.
8196 This form is typical of the primitive &odr; functions. They are named
8197 after the type of data that they encode or decode. They take an &odr;
8198 stream, an indirect reference to the type in question, and an
8199 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8200 of ASN.1) as parameters. They all return an integer value of either one
8202 When you use the primitive functions to construct encoders for complex
8203 types of your own, you should follow this model as well. This
8204 ensures that your new types can be reused as elements in yet more
8208 The <literal>o</literal> parameter should obviously refer to a properly
8209 initialized &odr; stream of the right type (encoding/decoding/printing)
8210 for the operation that you wish to perform.
8213 When encoding or printing, the function first looks at
8214 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8215 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8216 the data element is absent. If the <literal>optional</literal> parameter
8217 is nonzero, the function will return one (signifying success) without
8218 any further processing. If the <literal>optional</literal> is zero, an
8219 internal error flag is set in the &odr; stream, and the function will
8220 return 0. No further operations can be carried out on the stream without
8221 a call to the function <function>odr_reset()</function>.
8224 If <literal>*p</literal> is not a null pointer, it is expected to
8225 point to an instance of the data type. The data will be subjected to
8226 the encoding rules, and the result will be placed in the buffer held
8227 by the &odr; stream.
8230 The other ASN.1 primitives have similar functions that operate in
8234 <sect3 id="odr.boolean">
8235 <title>BOOLEAN</title>
8237 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8240 <sect3 id="odr.real">
8246 <sect3 id="odr.null">
8249 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8252 In this case, the value of **p is not important. If <literal>*p</literal>
8253 is different from the null pointer, the null value is present, otherwise
8257 <sect3 id="odr.octet.string">
8258 <title>OCTET STRING</title>
8260 typedef struct odr_oct
8266 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8270 The <literal>buf</literal> field should point to the character array
8271 that holds the octetstring. The <literal>len</literal> field holds the
8273 The character array need not be null terminated.
8276 To make things a little easier, an alternative is given for string
8277 types that are not expected to contain embedded NULL characters (eg.
8281 int odr_cstring(ODR o, char **p, int optional, const char *name);
8284 Which encoded or decodes between OCTETSTRING representations and
8285 null-terminates C strings.
8288 Functions are provided for the derived string types, eg:
8291 int odr_visiblestring(ODR o, char **p, int optional,
8295 <sect3 id="odr.bit.string">
8296 <title>BIT STRING</title>
8298 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8302 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8303 holding relatively brief bit strings, eg. for options fields, etc.
8304 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8305 gives the maximum possible number of bits.
8308 A set of macros are provided for manipulating the
8309 <literal>Odr_bitmask</literal> type:
8312 void ODR_MASK_ZERO(Odr_bitmask *b);
8314 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8316 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8318 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8321 The functions are modeled after the manipulation functions that
8322 accompany the <literal>fd_set</literal> type used by the
8323 <function>select(2)</function> call.
8324 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8325 new bitmask, to initialize the bits to zero.
8328 <sect3 id="odr.object.identifier">
8329 <title>OBJECT IDENTIFIER</title>
8331 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8334 The C OID representation is simply an array of integers, terminated by
8335 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8336 the <literal>short</literal> type).
8337 We suggest that you use the OID database module (see
8338 <xref linkend="tools.oid.database"/>) to handle object identifiers
8339 in your application.
8343 <sect2 id="odr.tagging.primitive.types">
8344 <title>Tagging Primitive Types</title>
8346 The simplest way of tagging a type is to use the
8347 <function>odr_implicit_tag()</function> or
8348 <function>odr_explicit_tag()</function> macros:
8351 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8352 int optional, const char *name);
8354 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8355 int optional, const char *name);
8358 To create a type derived from the integer type by implicit tagging, you
8362 MyInt ::= [210] IMPLICIT INTEGER
8365 In the &odr; system, this would be written like:
8368 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8370 return odr_implicit_tag(o, odr_integer, p,
8371 ODR_CONTEXT, 210, optional, name);
8375 The function <function>myInt()</function> can then be used like any of
8376 the primitive functions provided by &odr;. Note that the behavior of
8377 <function>odr_explicit_tag()</function>
8378 and <function>odr_implicit_tag()</function> macros
8379 act exactly the same as the functions they are applied to - they
8380 respond to error conditions, etc, in the same manner - they
8381 simply have three extra parameters. The class parameter may
8382 take one of the values: <literal>ODR_CONTEXT</literal>,
8383 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8384 <literal>/ODR_APPLICATION</literal>.
8387 <sect2 id="odr.constructed.types">
8388 <title>Constructed Types</title>
8390 Constructed types are created by combining primitive types. The
8391 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8392 (although adding the rest of the container types should be simple
8393 enough, if the need arises).
8396 For implementing SEQUENCEs, the functions
8399 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8400 int odr_sequence_end(ODR o);
8406 The <function>odr_sequence_begin()</function> function should be
8407 called in the beginning of a function that implements a SEQUENCE type.
8408 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8409 you're implementing), and the <literal>size</literal> of the type
8410 (typically a C structure). On encoding, it returns 1 if
8411 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8412 parameter is ignored. On decoding, it returns 1 if the type is found in
8413 the data stream. <literal>size</literal> bytes of memory are allocated,
8414 and <literal>*p</literal> is set to point to this space.
8415 <function>odr_sequence_end()</function> is called at the end of the
8416 complex function. Assume that a type is defined like this:
8419 MySequence ::= SEQUENCE {
8421 boolval BOOLEAN OPTIONAL
8425 The corresponding &odr; encoder/decoder function and the associated data
8426 structures could be written like this:
8429 typedef struct MySequence
8435 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8437 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8438 return optional && odr_ok(o);
8440 odr_integer(o, &(*p)->intval, 0, "intval") &&
8441 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8442 odr_sequence_end(o);
8446 Note the 1 in the call to <function>odr_bool()</function>, to mark
8447 that the sequence member is optional.
8448 If either of the member types had been tagged, the macros
8449 <function>odr_implicit_tag()</function> or
8450 <function>odr_explicit_tag()</function>
8451 could have been used.
8452 The new function can be used exactly like the standard functions provided
8453 with &odr;. It will encode, decode or pretty-print a data value of the
8454 <literal>MySequence</literal> type. We like to name types with an
8455 initial capital, as done in ASN.1 definitions, and to name the
8456 corresponding function with the first character of the name in lower case.
8457 You could, of course, name your structures, types, and functions any way
8458 you please - as long as you're consistent, and your code is easily readable.
8459 <literal>odr_ok</literal> is just that - a predicate that returns the
8460 state of the stream. It is used to ensure that the behavior of the new
8461 type is compatible with the interface of the primitive types.
8464 <sect2 id="odr.tagging.constructed.types">
8465 <title>Tagging Constructed Types</title>
8468 See <xref linkend="odr.tagging.primitive.types"/> for information
8469 on how to tag the primitive types, as well as types that are
8473 <sect3 id="odr.implicit.tagging">
8474 <title>Implicit Tagging</title>
8476 Assume the type above had been defined as
8479 MySequence ::= [10] IMPLICIT SEQUENCE {
8481 boolval BOOLEAN OPTIONAL
8485 You would implement this in &odr; by calling the function
8488 int odr_implicit_settag(ODR o, int class, int tag);
8491 which overrides the tag of the type immediately following it. The
8492 macro <function>odr_implicit_tag()</function> works by calling
8493 <function>odr_implicit_settag()</function> immediately
8494 before calling the function pointer argument.
8495 Your type function could look like this:
8498 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8500 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8501 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8502 return optional && odr_ok(o);
8504 odr_integer(o, &(*p)->intval, 0, "intval") &&
8505 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8506 odr_sequence_end(o);
8510 The definition of the structure <literal>MySequence</literal> would be
8514 <sect3 id="odr.explicit.tagging">
8515 <title>Explicit Tagging</title>
8517 Explicit tagging of constructed types is a little more complicated,
8518 since you are in effect adding a level of construction to the data.
8521 Assume the definition:
8524 MySequence ::= [10] IMPLICIT SEQUENCE {
8526 boolval BOOLEAN OPTIONAL
8530 Since the new type has an extra level of construction, two new functions
8531 are needed to encapsulate the base type:
8534 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8537 int odr_constructed_end(ODR o);
8540 Assume that the IMPLICIT in the type definition above were replaced
8541 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8542 would be equivalent). The structure definition would look the same,
8543 but the function would look like this:
8546 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8548 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8549 return optional && odr_ok(o);
8550 if (o->direction == ODR_DECODE)
8551 *p = odr_malloc(o, sizeof(**p));
8552 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8554 *p = 0; /* this is almost certainly a protocol error */
8558 odr_integer(o, &(*p)->intval, 0, "intval") &&
8559 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8560 odr_sequence_end(o) &&
8561 odr_constructed_end(o);
8565 Notice that the interface here gets kind of nasty. The reason is
8566 simple: Explicitly tagged, constructed types are fairly rare in
8567 the protocols that we care about, so the
8568 esthetic annoyance (not to mention the dangers of a cluttered
8569 interface) is less than the time that would be required to develop a
8570 better interface. Nevertheless, it is far from satisfying, and it's a
8571 point that will be worked on in the future. One option for you would
8572 be to simply apply the <function>odr_explicit_tag()</function> macro to
8573 the first function, and not
8574 have to worry about <function>odr_constructed_*</function> yourself.
8575 Incidentally, as you might have guessed, the
8576 <function>odr_sequence_</function> functions are themselves
8577 implemented using the <function>/odr_constructed_</function> functions.
8581 <sect2 id="odr.sequence.of">
8582 <title>SEQUENCE OF</title>
8584 To handle sequences (arrays) of a specific type, the function
8587 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8588 void *p, int *num, const char *name);
8591 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8592 function of the type. <literal>p</literal> is a pointer to an array of
8593 pointers to your type. <literal>num</literal> is the number of elements
8600 MyArray ::= SEQUENCE OF INTEGER
8603 The C representation might be
8606 typedef struct MyArray
8613 And the function might look like
8616 int myArray(ODR o, MyArray **p, int optional, const char *name)
8618 if (o->direction == ODR_DECODE)
8619 *p = odr_malloc(o, sizeof(**p));
8620 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8621 &(*p)->num_elements, name))
8624 return optional && odr_ok(o);
8628 <sect2 id="odr.choice.types">
8629 <title>CHOICE Types</title>
8631 The choice type is used fairly often in some ASN.1 definitions, so
8632 some work has gone into streamlining its interface.
8635 CHOICE types are handled by the function:
8638 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8642 The <literal>arm</literal> array is used to describe each of the possible
8643 types that the CHOICE type may assume. Internally in your application,
8644 the CHOICE type is represented as a discriminated union. That is, a
8645 C union accompanied by an integer (or enum) identifying the active
8647 <literal>whichp</literal> is a pointer to the union discriminator.
8648 When encoding, it is examined to determine the current type.
8649 When decoding, it is set to reference the type that was found in
8653 The Odr_arm type is defined thus:
8656 typedef struct odr_arm
8667 The interpretation of the fields are:
8671 <term>tagmode</term>
8672 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8673 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8674 to mark no tagging.</para></listitem>
8678 <listitem><para>The value of the discriminator that corresponds to
8679 this CHOICE element. Typically, it will be a #defined constant, or
8680 an enum member.</para></listitem>
8684 <listitem><para>A pointer to a function that implements the type of
8685 the CHOICE member. It may be either a standard &odr; type or a type
8686 defined by yourself.</para></listitem>
8690 <listitem><para>Name of tag.</para></listitem>
8694 A handy way to prepare the array for use by the
8695 <function>odr_choice()</function> function is to
8696 define it as a static, initialized array in the beginning of your
8697 decoding/encoding function. Assume the type definition:
8700 MyChoice ::= CHOICE {
8702 tagged [99] IMPLICIT INTEGER,
8707 Your C type might look like
8710 typedef struct MyChoice
8727 And your function could look like this:
8730 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8732 static Odr_arm arm[] =
8734 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8735 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8737 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8741 if (o->direction == ODR_DECODE)
8742 *p = odr_malloc(o, sizeof(**p);
8744 return optional && odr_ok(o);
8746 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8749 return optional && odr_ok(o);
8753 In some cases (say, a non-optional choice which is a member of a
8754 sequence), you can "embed" the union and its discriminator in the
8755 structure belonging to the enclosing type, and you won't need to
8756 fiddle with memory allocation to create a separate structure to
8757 wrap the discriminator and union.
8760 The corresponding function is somewhat nicer in the Sun XDR interface.
8761 Most of the complexity of this interface comes from the possibility of
8762 declaring sequence elements (including CHOICEs) optional.
8765 The ASN.1 specifications naturally requires that each member of a
8766 CHOICE have a distinct tag, so they can be told apart on decoding.
8767 Sometimes it can be useful to define a CHOICE that has multiple types
8768 that share the same tag. You'll need some other mechanism, perhaps
8769 keyed to the context of the CHOICE type. In effect, we would like to
8770 introduce a level of context-sensitiveness to our ASN.1 specification.
8771 When encoding an internal representation, we have no problem, as long
8772 as each CHOICE member has a distinct discriminator value. For
8773 decoding, we need a way to tell the choice function to look for a
8774 specific arm of the table. The function
8777 void odr_choice_bias(ODR o, int what);
8780 provides this functionality. When called, it leaves a notice for the next
8781 call to <function>odr_choice()</function> to be called on the decoding
8782 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8783 a <literal>which</literal> field equal to <literal>what</literal>
8787 The most important application (perhaps the only one, really) is in
8788 the definition of application-specific EXTERNAL encoders/decoders
8789 which will automatically decode an ANY member given the direct or
8794 <sect1 id="odr.debugging">
8795 <title>Debugging</title>
8797 The protocol modules are suffering somewhat from a lack of diagnostic
8798 tools at the moment. Specifically ways to pretty-print PDUs that
8799 aren't recognized by the system. We'll include something to this end
8800 in a not-too-distant release. In the meantime, what we do when we get
8801 packages we don't understand is to compile the ODR module with
8802 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
8803 information as it processes data units. With this output and the
8804 protocol specification (Z39.50), it is generally fairly easy to see
8809 <chapter id="comstack">
8810 <title>The COMSTACK Module</title>
8811 <sect1 id="comstack.synopsis">
8812 <title>Synopsis (blocking mode)</title>
8813 <programlisting><![CDATA[
8816 int size = 0, length_incoming;
8817 char server_address_str[] = "localhost:9999";
8818 void *server_address_ip;
8821 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
8822 int protocol_package_length = strlen(protocol_package);
8824 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
8826 perror("cs_create"); /* use perror() here since we have no stack yet */
8830 server_address_ip = cs_straddr(stack, server_address_str);
8831 if (!server_address_ip) {
8832 fprintf(stderr, "cs_straddr: address could not be resolved\n");
8836 status = cs_connect(stack, server_address_ip);
8838 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
8842 status = cs_rcvconnect(stack);
8844 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
8848 status = cs_put(stack, protocol_package, protocol_package_length);
8850 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
8854 /* Now get a response */
8855 length_incoming = cs_get(stack, &buf, &size);
8856 if (!length_incoming) {
8857 fprintf(stderr, "Connection closed\n");
8859 } else if (length_incoming < 0) {
8860 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
8865 fwrite(buf, length_incoming, 1, stdout);
8876 <sect1 id="comstack.introduction">
8877 <title>Introduction</title>
8880 subsystem provides a transparent interface to different types of transport
8881 stacks for the exchange of BER-encoded data and HTTP packets.
8882 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
8883 experimental SSL stack are supported, but others may be added in time.
8884 The philosophy of the
8885 module is to provide a simple interface by hiding unused options and
8886 facilities of the underlying libraries. This is always done at the risk
8887 of losing generality, and it may prove that the interface will need
8892 There hasn't been interest in the XTImOSI stack for some years.
8893 Therefore, it is no longer supported.
8897 The interface is implemented in such a fashion that only the
8898 sub-layers constructed to the transport methods that you wish to
8899 use in your application are linked in.
8902 You will note that even though simplicity was a goal in the design,
8903 the interface is still orders of magnitudes more complex than the
8904 transport systems found in many other packages. One reason is that
8905 the interface needs to support the somewhat different requirements of
8906 the different lower-layer communications stacks; another important
8907 reason is that the interface seeks to provide a more or less
8908 industrial-strength approach to asynchronous event-handling.
8909 When no function is allowed to block, things get more complex -
8910 particularly on the server side.
8911 We urge you to have a look at the demonstration client and server
8912 provided with the package. They are meant to be easily readable and
8913 instructive, while still being at least moderately useful.
8916 <sect1 id="comstack.common">
8917 <title>Common Functions</title>
8918 <sect2 id="comstack.managing.endpoints">
8919 <title>Managing Endpoints</title>
8921 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
8924 Creates an instance of the protocol stack - a communications endpoint.
8925 The <literal>type</literal> parameter determines the mode
8926 of communication. At present the following values are supported:
8930 <term><literal>tcpip_type</literal></term>
8931 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
8935 <term><literal>ssl_type</literal></term>
8936 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
8937 is experimental and is not fully implemented. If
8938 HTTP is used, this effectively is HTTPS.
8942 <term><literal>unix_type</literal></term>
8943 <listitem><para>Unix socket (unix only). Local Transfer via
8944 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
8945 <manvolnum>7</manvolnum></citerefentry>.
8950 The <function>cs_create</function> function returns a null-pointer
8951 if a system error occurs.
8952 The <literal>blocking</literal> parameter should be one if
8953 you wish the association to operate in blocking mode, zero otherwise.
8954 The <literal>protocol</literal> field should be
8955 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
8956 Protocol <literal>PROTO_SR</literal> is no longer supported.
8959 void cs_close(COMSTACK handle);
8962 Closes the connection (as elegantly as the lower layers will permit),
8963 and releases the resources pointed to by the
8964 <literal>handle</literal>
8966 <literal>handle</literal>
8967 should not be referenced again after this call.
8971 We really need a soft disconnect, don't we?
8975 <sect2 id="comstack.data.exchange">
8976 <title>Data Exchange</title>
8978 int cs_put(COMSTACK handle, char *buf, int len);
8981 Sends <literal>buf</literal> down the wire.
8982 In blocking mode, this function will return only when a full buffer has
8983 been written, or an error has occurred. In nonblocking mode, it's
8984 possible that the function will be unable to send the full buffer
8985 at once, which will be indicated by a return value of 1.
8986 The function will keep track of the number of octets already written; you
8987 should call it repeatedly with the same values of <literal>buf</literal>
8988 and <literal>len</literal>, until the buffer has been transmitted.
8989 When a full buffer has been sent, the function will return 0 for
8990 success. -1 indicates an error condition (see below).
8993 int cs_get(COMSTACK handle, char **buf, int *size);
8996 Receives a PDU or HTTP Response from the peer. Returns the number of
8998 In nonblocking mode, it is possible that not all of the packet can be
8999 read at once. In this case, the function returns 1. To simplify the
9000 interface, the function is
9001 responsible for managing the size of the buffer. It will be reallocated
9002 if necessary to contain large packages, and will sometimes be moved
9003 around internally by the subsystem when partial packages are read. Before
9005 <function>cs_get</function>
9006 for the fist time, the buffer can be initialized to the null pointer,
9007 and the length should also be set to 0 - cs_get will perform a
9008 <function>malloc(2)</function>
9009 on the buffer for you. When a full buffer has been read, the size of
9010 the package is returned (which will always be greater than 1). -1
9011 indicates an error condition.
9014 See also the <function>cs_more()</function> function below.
9017 int cs_more(COMSTACK handle);
9020 The <function>cs_more()</function> function should be used in conjunction
9021 with <function>cs_get</function> and
9022 <function>select(2)</function>.
9023 The <function>cs_get()</function> function will sometimes
9024 (notably in the TCP/IP mode) read more than a single protocol package
9025 off the network. When this happens, the extra package is stored
9026 by the subsystem. After calling <function>cs_get()</function>, and before
9027 waiting for more input, You should always call
9028 <function>cs_more()</function>
9029 to check if there's a full protocol package already read. If
9030 <function>cs_more()</function>
9032 <function>cs_get()</function>
9033 can be used to immediately fetch the new package. For the
9035 subsystem, the function should always return 0, but if you want your
9036 stuff to be protocol independent, you should use it.
9040 The <function>cs_more()</function>
9041 function is required because the RFC1729-method
9042 does not provide a way of separating individual PDUs, short of
9043 partially decoding the BER. Some other implementations will carefully
9044 nibble at the packet by calling
9045 <function>read(2)</function>
9046 several times. This was felt to be too inefficient (or at least
9047 clumsy) - hence the call for this extra function.
9051 int cs_look(COMSTACK handle);
9054 This function is useful when you're operating in nonblocking
9056 <function>select(2)</function>
9057 tells you there's something happening on the line. It returns one of
9058 the following values:
9062 <term>CS_NONE</term>
9064 No event is pending. The data found on the line was not a
9069 <term>CS_CONNECT</term>
9071 A response to your connect request has been received. Call
9072 <function>cs_rcvconnect</function>
9073 to process the event and to finalize the connection establishment.
9077 <term>CS_DISCON</term>
9079 The other side has closed the connection (or maybe sent a disconnect
9080 request - but do we care? Maybe later). Call
9081 <function>cs_close</function> to close your end of the association
9086 <term>CS_LISTEN</term>
9088 A connect request has been received.
9089 Call <function>cs_listen</function> to process the event.
9093 <term>CS_DATA</term>
9095 There's data to be found on the line.
9096 Call <function>cs_get</function> to get it.
9102 You should be aware that even if
9103 <function>cs_look()</function>
9104 tells you that there's an event event pending, the corresponding
9105 function may still return and tell you there was nothing to be found.
9106 This means that only part of a package was available for reading. The
9107 same event will show up again, when more data has arrived.
9111 int cs_fileno(COMSTACK h);
9114 Returns the file descriptor of the association. Use this when
9115 file-level operations on the endpoint are required
9116 (<function>select(2)</function> operations, specifically).
9120 <sect1 id="comstack.client">
9121 <title>Client Side</title>
9123 int cs_connect(COMSTACK handle, void *address);
9126 Initiate a connection with the target at <literal>address</literal>
9127 (more on addresses below). The function will return 0 on success, and 1 if
9128 the operation does not complete immediately (this will only
9129 happen on a nonblocking endpoint). In this case, use
9130 <function>cs_rcvconnect</function> to complete the operation,
9131 when <function>select(2)</function> or <function>poll(2)</function>
9132 reports input pending on the association.
9135 int cs_rcvconnect(COMSTACK handle);
9138 Complete a connect operation initiated by <function>cs_connect()</function>.
9139 It will return 0 on success; 1 if the operation has not yet completed (in
9140 this case, call the function again later); -1 if an error has occurred.
9143 <sect1 id="comstack.server">
9144 <title>Server Side</title>
9146 To establish a server under the <application>inetd</application>
9150 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9154 The <literal>socket</literal> parameter is an established socket (when
9155 your application is invoked from <application>inetd</application>, the
9156 socket will typically be 0.
9157 The following parameters are identical to the ones for
9158 <function>cs_create</function>.
9161 int cs_bind(COMSTACK handle, void *address, int mode)
9164 Binds a local address to the endpoint. Read about addresses below. The
9165 <literal>mode</literal> parameter should be either
9166 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9169 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9172 Call this to process incoming events on an endpoint that has been
9173 bound in listening mode. It will return 0 to indicate that the connect
9174 request has been received, 1 to signal a partial reception, and -1 to
9175 indicate an error condition.
9178 COMSTACK cs_accept(COMSTACK handle);
9181 This finalizes the server-side association establishment, after
9182 cs_listen has completed successfully. It returns a new connection
9183 endpoint, which represents the new association. The application will
9184 typically wish to fork off a process to handle the association at this
9185 point, and continue listen for new connections on the old
9186 <literal>handle</literal>.
9189 You can use the call
9192 const char *cs_addrstr(COMSTACK);
9195 on an established connection to retrieve the host-name of the remote host.
9199 You may need to use this function with some care if your
9200 name server service is slow or unreliable
9204 <sect1 id="comstack.addresses">
9205 <title>Addresses</title>
9207 The low-level format of the addresses are different depending on the
9208 mode of communication you have chosen. A function is provided by each
9209 of the lower layers to map a user-friendly string-form address to the
9210 binary form required by the lower layers.
9213 void *cs_straddr(COMSTACK handle, const char *str);
9216 The format for TCP/IP and SSL addresses is:
9219 <host> [ ':' <portnum> ]
9222 The <literal>hostname</literal> can be either a domain name or an
9223 IP address. The port number, if omitted, defaults to 210.
9226 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9227 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9228 IPV4 binding as well (bindv6only=0),
9229 The special hostname <literal>@4</literal> binds to
9230 <literal>INADDR_ANY</literal> (IPV4 only listener).
9231 The special hostname <literal>@6</literal> binds to
9232 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9235 For UNIX sockets, the format of an address is the socket filename.
9238 When a connection has been established, you can use
9241 const char *cs_addrstr(COMSTACK h);
9244 to retrieve the host name of the peer system. The function returns
9245 a pointer to a static area, which is overwritten on the next call
9249 A fairly recent addition to the &comstack; module is the utility
9253 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9256 which is just a wrapper for <function>cs_create</function> and
9257 <function>cs_straddr</function>. The <parameter>str</parameter>
9258 is similar to that described for <function>cs_straddr</function>
9259 but with a prefix denoting the &comstack; type. Prefixes supported
9260 are <literal>tcp:</literal>, <literal>unix:</literal> and
9261 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9262 If no prefix is given, then TCP/IP is used.
9263 The <parameter>blocking</parameter> is passed to
9264 function <function>cs_create</function>. The third parameter
9265 <parameter>vp</parameter> is a pointer to &comstack; stack type
9267 Parameter <parameter>vp</parameter> is reserved for future use.
9268 Set it to <literal>NULL</literal>.
9271 <sect1 id="comstack.ssl">
9275 void *cs_get_ssl(COMSTACK cs);
9277 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9278 is not of type SSL, NULL is returned.
9282 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9284 Sets SSL context for comstack. The parameter is expected to be of type
9285 <literal>SSL_CTX *</literal>. This function should be called just
9286 after comstack has been created (before connect, bind, etc).
9287 This function returns 1 for success; 0 for failure.
9291 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9293 Sets SSL certificate for comstack as a PEM file. This function
9294 returns 1 for success; 0 for failure.
9298 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9300 This function returns the peer certificate. If successful,
9301 <literal>*buf</literal> and <literal>*len</literal> holds
9302 X509 buffer and length respectively. Buffer should be freed
9303 with <literal>xfree</literal>. This function returns 1 for success;
9307 <sect1 id="comstack.diagnostics">
9308 <title>Diagnostics</title>
9310 All functions return -1 if an error occurs. Typically, the functions
9311 will return 0 on success, but the data exchange functions
9312 (<function>cs_get</function>, <function>cs_put</function>,
9313 <function>cs_more</function>) follow special rules. Consult their
9317 The error code for the COMSTACK can be retrieved using C macro
9318 <function>cs_errno</function> which will return one
9319 of the error codes <literal>CSYSERR</literal>,
9320 <literal>CSOUTSTATE</literal>,
9321 <literal>CSNODATA</literal>, ...
9324 int cs_errno(COMSTACK handle);
9327 You can the textual representation of the error code
9328 by using <function>cs_errmsg</function> - which
9329 works like <function>strerror(3)</function>
9332 const char *cs_errmsg(int n);
9335 It is also possible to get straight to the textual represenataion
9336 without the error code by using
9337 <function>cs_strerror</function>.
9340 const char *cs_strerror(COMSTACK h);
9343 <sect1 id="comstack.summary">
9344 <title>Summary and Synopsis</title>
9346 #include <yaz/comstack.h>
9348 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9349 #include <yaz/unix.h> /* this is for UNIX socket support */
9351 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9353 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9355 COMSTACK cs_create_host(const char *str, int blocking,
9358 int cs_bind(COMSTACK handle, int mode);
9360 int cs_connect(COMSTACK handle, void *address);
9362 int cs_rcvconnect(COMSTACK handle);
9364 int cs_listen(COMSTACK handle);
9366 COMSTACK cs_accept(COMSTACK handle);
9368 int cs_put(COMSTACK handle, char *buf, int len);
9370 int cs_get(COMSTACK handle, char **buf, int *size);
9372 int cs_more(COMSTACK handle);
9374 void cs_close(COMSTACK handle);
9376 int cs_look(COMSTACK handle);
9378 void *cs_straddr(COMSTACK handle, const char *str);
9380 const char *cs_addrstr(COMSTACK h);
9385 <chapter id="future">
9386 <title>Future Directions</title>
9388 We have a new and better version of the front-end server on the drawing
9389 board. Resources and external commitments will govern when we'll be
9390 able to do something real with it. Features should include greater
9391 flexibility, greater support for access/resource control, and easy
9392 support for Explain (possibly with Zebra as an extra database engine).
9395 &yaz; is a BER toolkit and as such should support all protocols
9396 out there based on that. We'd like to see running ILL applications.
9397 It shouldn't be that hard. Another thing that would be interesting is
9398 LDAP. Maybe a generic framework for doing IR using both LDAP and
9399 Z39.50 transparently.
9402 The SOAP implementation is incomplete. In the future we hope
9403 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9404 The authors of libxml2 are already working on XML Schema / RelaxNG
9405 compilers so this may not be too hard.
9408 It would be neat to have a proper module mechanism for the Generic
9409 Frontend Server so that backend would be dynamically
9410 loaded (as shared objects / DLLs).
9413 Other than that, &yaz; generally moves in the directions which appear to
9414 make the most people happy (including ourselves, as prime users of the
9415 software). If there's something you'd like to see in here, then drop
9416 us a note and let's see what we can come up with.
9419 <reference id="reference">
9420 <title>Reference</title>
9421 <partintro id="reference-introduction">
9423 The material in this chapter is drawn directly from the individual
9429 <appendix id="list-oids">
9430 <title>List of Object Identifiers</title>
9432 These is a list of object identifiers that are built into YAZ.
9436 <appendix id="bib1-diagnostics">
9437 <title>Bib-1 diagnostics</title>
9439 List of Bib-1 diagnostics that are known to YAZ.
9443 <appendix id="sru-diagnostics">
9444 <title>SRU diagnostics</title>
9446 List of SRU diagnostics that are known to YAZ.
9450 <appendix id="license">
9451 <title>License</title>
9452 <sect1 id="license.indexdata">
9453 <title>Index Data Copyright</title>
9455 Copyright © ©right-year; Index Data.
9458 All rights reserved.
9461 Redistribution and use in source and binary forms, with or without
9462 modification, are permitted provided that the following conditions are met:
9467 Redistributions of source code must retain the above copyright
9468 notice, this list of conditions and the following disclaimer.
9473 Redistributions in binary form must reproduce the above copyright
9474 notice, this list of conditions and the following disclaimer in the
9475 documentation and/or other materials provided with the distribution.
9480 Neither the name of Index Data nor the names of its contributors
9481 may be used to endorse or promote products derived from this
9482 software without specific prior written permission.
9487 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9488 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9489 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9490 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9491 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9492 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9493 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9494 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9495 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9496 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9501 <appendix id="indexdata">
9502 <title>About Index Data</title>
9504 Index Data is a consulting and software-development enterprise that
9505 specializes in library and information management systems. Our
9506 interests and expertise span a broad range of related fields, and one
9507 of our primary, long-term objectives is the development of a powerful
9508 information management
9509 system with open network interfaces and hyper-media capabilities.
9511 We make this software available free of charge, on a fairly unrestrictive
9512 license; as a service to the networking community, and to further the
9513 development of quality software for open network communication.
9515 We'll be happy to answer questions about the software, and about ourselves
9521 <street>Amagerfælledvej 56</street>
9522 <postcode>2300 Copenhagen S</postcode>
9523 <country>Denmark</country>
9524 Email <email>info@indexdata.dk</email>
9528 The Hacker's Jargon File has the following to say about the
9530 prefix "YA" in the name of a software product.
9534 Yet Another. adj. 1. Of your own work: A
9535 humorous allusion often used in titles to acknowledge that the
9536 topic is not original, though the content is. As in "Yet Another
9537 AI Group" or "Yet Another Simulated Annealing Algorithm".
9539 others' work: Describes something of which there are already far
9544 <appendix id="credits">
9545 <title>Credits</title>
9547 This appendix lists individuals that have contributed in the development
9548 of &yaz;. Some have contributed with code, while others have provided bug
9549 fixes or suggestions. If we're missing somebody, of if you, for
9550 whatever reason, don't like to be listed here, let us know.
9560 Morten Bøgeskov
9581 Mads Bondo Dydensborg
9590 Morten Garkier Hendriksen
9647 Tom André Øverland
9653 <!-- Keep this comment at the end of the file
9656 nxml-child-indent: 1