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14 <title>YAZ User's Guide and Reference</title>
16 <author><firstname>Sebastian</firstname><surname>Hammer</surname></author>
17 <author><firstname>Adam</firstname><surname>Dickmeiss</surname></author>
18 <author><firstname>Mike</firstname><surname>Taylor</surname></author>
19 <author><firstname>Heikki</firstname><surname>Levanto</surname></author>
20 <author><firstname>Dennis</firstname><surname>Schafroth</surname></author>
22 <releaseinfo>&version;</releaseinfo>
24 <year>©right-year;</year>
25 <holder>Index Data</holder>
29 This document is the programmer's guide and reference to the &yaz;
30 package version &version;. &yaz; is a compact toolkit that provides
31 access to the Z39.50 and SRU/Solr protocols, as well as a set of
32 higher-level tools for implementing the server and client
34 The documentation can be used on its own, or as a reference when
35 looking at the example applications provided with the package.
40 <imagedata fileref="common/id.png" format="PNG"/>
43 <imagedata fileref="common/id.eps" format="EPS"/>
48 <chapter id="introduction">
49 <title>Introduction</title>
51 &yaz; is a C/C++ library for information retrieval applications
52 using the Z39.50/SRU/Solr protocols for information retrieval.
60 <ulink url="&url.z39.50;">Z39.50</ulink> version 3 support.
61 Amendments and Z39.50-2002 revision is supported.
67 <ulink url="&url.sru;">SRU GET/POST/SOAP</ulink>
68 version 1.1, 1.2 and 2.0 (over HTTP and HTTPS).
73 Includes BER encoders/decoders for the
74 <ulink url="&url.ill;">ISO ILL</ulink>
81 <ulink url="&url.solr;">Solr</ulink> Web Service version 1.4.x
87 Supports the following transports: BER over TCP/IP
88 (<ulink url="&url.ber.over.tcpip;">RFC1729</ulink>),
89 BER over unix local socket, and
90 <ulink url="&url.http.1.1;">HTTP 1.1</ulink>.
95 Secure Socket Layer support using
96 <ulink url="&url.gnutls;">GnuTLS</ulink>.
97 If enabled, &yaz; uses HTTPS transport (for SOAP) or
98 "Secure BER" (for Z39.50).
104 <ulink url="&url.zoom;">ZOOM</ulink> C API implementing
105 Z39.50, SRU and Solr Web Service.
110 The &yaz; library offers a set of useful utilities
111 related to the protocols, such as MARC (ISO2709) parser,
112 CCL (ISO8777) parser,
113 <ulink url="&url.cql;">CQL</ulink>
114 parser, memory management routines, character set conversion.
119 Portable code. &yaz; compiles out-of-the box on most Unixes and
120 on Windows using Microsoft Visual C++.
125 Fast operation. The C based BER encoders/decoders as well
126 as the server component of &yaz; is very fast.
131 Liberal license that allows for commercial use of &yaz;.
137 <sect1 id="introduction.reading">
138 <title>Reading this Manual</title>
140 Most implementors only need to read a fraction of the
141 material in thie manual, so a quick walkthrough of the chapters
147 <xref linkend="installation"/> contains installation
148 instructions for &yaz;. You don't need reading this
149 if you expect to download &yaz; binaries.
150 However, the chapter contains information about how
151 to make <emphasis>your</emphasis> application link
157 <xref linkend="zoom"/> describes the ZOOM API of &yaz;.
158 This is definitely worth a read if you wish to develop a Z39.50/SRU
164 <xref linkend="server"/> describes the generic frontend server
165 and explains how to develop server Z39.50/SRU applications for &yaz;.
166 Obviously worth reading if you're to develop a server.
171 <xref linkend="yaz-client"/> describes how to use the &yaz; Z39.50
172 client. If you're developer and wish to test your server
173 or a server from another party, you might find this chapter
179 <xref linkend="asn"/> documents the most commonly used Z39.50
180 C data structures offered by the &yaz; API. Client
181 developers using ZOOM and non-Z39.50 implementors may skip this.
186 <xref linkend="soap"/> describes how SRU and SOAP is used
187 in &yaz;. Only if you're developing SRU applications
188 this section is a must.
193 <xref linkend="tools"/> contains sections for the various
194 tools offered by &yaz;. Scan through the material quickly
195 and see what's relevant to you! SRU implementors
196 might find the <link linkend="cql">CQL</link> section
202 <xref linkend="odr"/> goes through the details of the
203 ODR module which is the work horse that encodes and decodes
204 BER packages. Implementors using ZOOM only, do <emphasis>not</emphasis>
206 Most other Z39.50 implementors only need to read the first two
207 sections (<xref linkend="odr.introduction"/> and
208 <xref linkend="odr.use"/>).
213 <xref linkend="comstack"/> describes the network layer module
214 COMSTACK. Implementors using ZOOM or the generic frontend server
215 may skip this. Others, presumably, handling client/server
216 communication on their own should read this.
221 <sect1 id="introduction.api">
222 <title>The API</title>
224 The <ulink url="&url.yaz;">&yaz;</ulink>
225 toolkit offers several different levels of access to the
226 <ulink url="&url.z39.50;">ISO23950/Z39.50</ulink>,
227 <ulink url="&url.ill;">ILL</ulink> and
228 <ulink url="&url.sru;">SRU</ulink>
230 The level that you need to use depends on your requirements, and
231 the role (server or client) that you want to implement.
232 If you're developing a client application you should consider the
233 <link linkend="zoom">ZOOM</link> API.
234 It is, by far, the easiest way to develop clients in C.
235 Server implementers should consider the
236 <link linkend="server">generic frontend server</link>.
237 None of those high-level APIs support the whole protocol, but
238 they do include most facilities used in existing Z39.50 applications.
241 If you're using 'exotic' functionality (meaning anything not included in
242 the high-level APIs), developing non-standard extensions to Z39.50 or
243 you're going to develop an ILL application you'll have to learn the lower
247 The YAZ toolkit modules is shown in figure <xref linkend="yaz.layer"/>.
249 <figure id="yaz.layer">
250 <title>YAZ layers</title>
253 <imagedata fileref="apilayer.png" format="PNG"/>
256 <imagedata fileref="apilayer.eps" format="EPS"/>
261 There are four layers.
264 <para>A client or server application (or both).
265 This layer includes ZOOM and the generic frontend server.
270 The second layer provides a C represenation of the
271 protocol units (packages) for Z39.50 ASN.1, ILL ASN.1,
277 The third layer encodes and decodes protocol data units to
278 simple packages (buffer with certain length). The &odr; module
279 encodes and decodes BER whereas the HTTP modules encodes and
280 decodes HTTP ruquests/responses.
285 The lowest layer is &comstack; which exchanges the encoded packages
286 with a peer process over a network.
292 The &asn; module represents the ASN.1 definition of
293 the Z39.50 protocol. It establishes a set of type and
294 structure definitions, with one structure for each of the top-level
295 PDUs, and one structure or type for each of the contained ASN.1 types.
296 For primitive types, or other types that are defined by the ASN.1
297 standard itself (such as the EXTERNAL type), the C representation is
298 provided by the &odr; (Open Data Representation) subsystem.
301 &odr; is a basic mechanism for representing an
302 ASN.1 type in the C programming language, and for implementing BER
303 encoders and decoders for values of that type. The types defined in
304 the &asn; module generally have the prefix <literal>Z_</literal>, and
305 a suffix corresponding to the name of the type in the ASN.1
306 specification of the protocol (generally Z39.50-1995). In the case of
307 base types (those originating in the ASN.1 standard itself), the prefix
308 <literal>Odr_</literal> is sometimes seen. Either way, look for
309 the actual definition in either <filename>z-core.h</filename> (for the types
310 from the protocol), <filename>odr.h</filename> (for the primitive ASN.1
312 The &asn; library also provides functions (which are, in turn,
313 defined using &odr; primitives) for encoding and decoding data values.
314 Their general form is
316 <funcprototype><funcdef>int <function>z_<replaceable>xxx</replaceable></function></funcdef>
317 <paramdef>ODR <parameter>o</parameter></paramdef>
318 <paramdef>Z_<replaceable>xxx</replaceable> **<parameter>p</parameter></paramdef>
319 <paramdef>int <parameter>optional</parameter></paramdef>
320 <paramdef>const char *<parameter>name</parameter></paramdef>
323 (note the lower-case "z" in the function name)
327 If you are using the premade definitions of the &asn; module, and you
328 are not adding new protocol of your own, the only parts of &odr; that you
329 need to worry about are documented in
330 <xref linkend="odr.use"/>.
334 When you have created a BER-encoded buffer, you can use the &comstack;
335 subsystem to transmit (or receive) data over the network. The &comstack;
336 module provides simple functions for establishing a connection
337 (passively or actively, depending on the role of your application),
338 and for exchanging BER-encoded PDUs over that connection. When you
339 create a connection endpoint, you need to specify what transport to
340 use (TCP/IP, SSL or UNIX sockets).
341 For the remainder of the connection's lifetime, you don't have
342 to worry about the underlying transport protocol at all - the &comstack;
343 will ensure that the correct mechanism is used.
346 We call the combined interfaces to &odr;, &asn;, and &comstack; the service
347 level API. It's the API that most closely models the Z39.50
348 service/protocol definition, and it provides unlimited access to all
349 fields and facilities of the protocol definitions.
352 The reason that the &yaz; service-level API is a conglomerate of the
353 APIs from three different submodules is twofold. First, we wanted to allow
354 the user a choice of different options for each major task. For instance,
355 if you don't like the protocol API provided by &odr;/&asn;, you
356 can use SNACC or BERUtils instead, and still have the benefits of the
357 transparent transport approach of the &comstack; module. Secondly,
358 we realize that you may have to fit the toolkit into an existing
359 event-processing structure, in a way that is incompatible with
360 the &comstack; interface or some other part of &yaz;.
364 <chapter id="installation">
365 <title>Compilation and Installation</title>
366 <sect1 id="installation-introduction">
367 <title>Introduction</title>
369 The latest version of the software will generally be found at:
372 <ulink url="&url.yaz.download;"/>
375 We have tried our best to keep the software portable, and on many
376 platforms, you should be able to compile everything with little or
380 The software is regularly tested on
381 <ulink url="&url.debian;">Debian GNU/Linux</ulink>,
382 <ulink url="&url.centos;">CentOS</ulink>,
383 <ulink url="&url.ubuntu;">Ubuntu Linux</ulink>,
384 <ulink url="&url.freebsd;">FreeBSD (i386)</ulink>,
385 <ulink url="&url.macosx;">MAC OSX</ulink>,
386 <ulink url="&url.solaris;">Solaris</ulink>,
387 Windows 7, Windows XP.
390 Some versions have be known to work on HP/UX,
391 DEC Unix, <ulink url="&url.netbsd;">NetBSD</ulink>,
392 <ulink url="&url.openbsd;">OpenBSD</ulink>,
394 Data General DG/UX (with some CFLAGS tinkering),
395 SGI/IRIX, DDE Supermax, Apple Macintosh (using the Codewarrior programming
396 environment and the GUSI socket libraries),
400 If you move the software to other platforms, we'd be grateful if you'd
401 let us know about it. If you run into difficulties, we will try to help
402 if we can, and if you solve the problems, we would be happy to include
403 your fixes in the next release. So far, we have mostly avoided
404 <literal>#ifdefs</literal> for individual platforms, and we'd
405 like to keep it that way as far as it makes sense.
408 We maintain a mailing-list for the purpose of announcing new releases and
409 bug-fixes, as well as general discussion. Subscribe by
411 <ulink url="&url.yaz.mailinglist;">here</ulink>.
412 General questions and problems can be directed at
413 <ulink url="&url.yaz.mail;"/>, or the address given at the top of
417 <sect1 id="installation.unix"><title>UNIX</title>
420 <ulink url="&url.debian;">Debian GNU/Linux</ulink> (i386 and amd64),
421 <ulink url="&url.ubuntu;">Ubuntu</ulink> (i386 and amd64)
423 <ulink url="&url.centos;">CentOS</ulink> (amd64 only) packages for &yaz;.
424 You should be able to create packages for other CPUs by building
425 them from the source package.
428 YAZ is also part of several packages repositories. Some of them are
433 Solaris CSW: <ulink url="http://www.opencsw.org/packages/yaz/"/>
438 Solaris: <ulink url="http://unixpackages.com"/>
443 FreeBSD: <ulink url="http://www.freshports.org/net/yaz"/>
448 Debian: <ulink url="http://packages.debian.org/search?keywords=yaz"/>
453 Ubuntu: <ulink url="https://launchpad.net/ubuntu/+source/yaz"/>
459 <ulink url="http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/net/yaz/README.html"/>
463 <sect2 id="installation.source.unix">
464 <title>Compiling from source on Unix</title>
466 Note that if your system doesn't have a native ANSI C compiler, you may
467 have to acquire one separately. We recommend
468 <ulink url="&url.gcc;">GCC</ulink>.
471 If you wish to use character set conversion facilities in &yaz; or if you
472 are compiling &yaz; for use with Zebra it is a good idea to ensure that
473 the iconv library is installed. Some Unixes today already have it
475 <ulink url="&url.libiconv;">GNU libiconv</ulink>.
478 YAZ 3.0.16 and later includes a wrapper for the
479 <ulink url="&url.icu;">ICU</ulink>
480 (International Components for Unicode).
481 In order to use this, the developer version of the ICU library
482 must be available. ICU support is recommended for applications
483 such as Pazpar2 and Zebra.
486 The <ulink url="&url.libxslt;">libxslt</ulink>,
487 <ulink url="&url.libxml2;">libxml2</ulink> librararies are required
488 if &yaz; is to support SRU/Solr.
489 These libraries are very portable and should compile out-of-the
490 box on virtually all Unix platforms. It is available in binary
491 forms for Linux and others.
495 <ulink url="&url.autoconf;">Autoconf</ulink>,
496 <ulink url="&url.automake;">Automake</ulink> and
497 <ulink url="&url.libtool;">Libtool</ulink>
498 are used to generate Makefiles and configure &yaz; for the system.
499 You do <emphasis>not</emphasis> these tools unless you're using the
500 Git version of &yaz;.
503 The CQL parser for &yaz; is built using
504 GNU <ulink url="&url.bison;">Bison</ulink>.
505 This tool is only needed if you're using the Git version of &yaz;.
508 &yaz; includes a tiny ASN.1 compiler. This compiler is
509 written in <ulink url="&url.tcl;">Tcl</ulink>.
510 But as for Bison you do not need it unless you're using Git
511 version of &yaz; or you're using the compiler to built own codecs
515 Generally it should be sufficient to run configure without options,
522 The configure script attempts to use use the C compiler specified by
523 the <literal>CC</literal> environment variable. If not set, GNU C will be
524 used if it is available. The <literal>CFLAGS</literal> environment
525 variable holds options to be passed to the C compiler. If you're using
526 Bourne-compatible shell you may pass something like this to use a
527 particular C compiler with optimization enabled:
530 CC=/opt/ccs/bin/cc CFLAGS=-O ./configure
533 To customize &yaz;, the configure script also accepts a set of options.
534 The most important are:
538 <literal>--prefix</literal>=<replaceable>prefix</replaceable>
541 <para>Specifies installation prefix for &yaz;. This is
542 only needed if you run <literal>make install</literal> later to
543 perform a "system" installation. The prefix is
544 <literal>/usr/local</literal> if not specified.
550 <literal>--enable-tcpd</literal>
553 <para>The front end server will be built using Wietse's
554 <ulink url="&url.tcpwrapper;">TCP wrapper library</ulink>.
555 It allows you to allow/deny clients depending on IP number.
556 The TCP wrapper library is often used in GNU/Linux and
560 <refentrytitle>hosts_access</refentrytitle>
561 <manvolnum>5</manvolnum>
565 <refentrytitle>tcpd</refentrytitle>
566 <manvolnum>8</manvolnum>
573 <literal>--enable-threads</literal>
576 <para>&yaz; will be built using POSIX threads.
577 Specifically, <constant>_REENTRANT</constant> will be defined during
584 <literal>--disable-shared</literal>
587 <para>The make process will not create shared
588 libraries (also known as shared objects <filename>.so</filename>).
589 By default, shared libraries are created -
590 equivalent to <literal>--enable-shared</literal>.
596 <literal>--disable-shared</literal>
599 <para>The make process will not create
600 static libraries (<filename>.a</filename>).
601 By default, static libraries are created -
602 equivalent to <literal>--enable-static</literal>.
608 <literal>--with-iconv</literal>[=<replaceable>prefix</replaceable>]
611 <para>Compile &yaz; with iconv library in directory
612 <replaceable>prefix</replaceable>. By default configure will
613 search for iconv on the system. Use this option if it
614 doesn't find iconv. Alternatively,
615 <literal>--without-iconv</literal>, can be uset to force &yaz;
622 <literal>--with-xslt</literal>[=<replaceable>prefix</replaceable>]
625 <para>Compile &yaz; with
626 <ulink url="&url.libxslt;">libxslt</ulink> in directory
627 <replaceable>prefix</replaceable>.
628 Use this option if you want XSLT and XML support.
629 By default, configure will
630 search for libxslt on the system. Use this option if it
631 libxslt is not found automatically. Alternatively,
632 <literal>--without-xslt</literal>, can be used to force &yaz;
639 <literal>--with-xml2</literal>[=<replaceable>prefix</replaceable>]
642 <para>Compile &yaz; with
643 <ulink url="&url.libxml2;">libxml2</ulink> in directory
644 <replaceable>prefix</replaceable>.
645 Use this option if you want &yaz; to use XML and support SRU/Solr.
646 By default, configure will
647 search for libxml2 on the system. Use this option if it
648 libxml2 is not found automatically. Alternatively,
649 <literal>--without-xml2</literal>, can be used to force &yaz;
653 Note that option <literal>--with-xslt</literal>
654 also enables libxml2.
660 <literal>--with-gnutls</literal>[=<replaceable>prefix</replaceable>]
663 <para>&yaz; will be linked with the GNU TLS libraries and
664 an SSL COMSTACK will be provided. By default configure enables
665 SSL support for YAZ if the GNU TLS development libraries are found
672 <literal>--with-icu</literal>[=<replaceable>prefix</replaceable>]
675 <para>&yaz; will be linked the
676 <ulink url="&url.icu;">ICU</ulink> library in the prefix if given.
677 If prefix is not given, the libraries exposed by the script
678 <application>icu-config</application> will be used if found.
685 <literal>--with-libgcrypt</literal>[=<replaceable>prefix</replaceable>]
688 <para>&yaz; will be linked with
689 <ulink url="&url.libgcrypt;">Libgcrypt</ulink> in the prefix if given.
690 If prefix is not given, the libraries exposed by the script
691 <application>libgcrypt-config</application> will be used if found.
697 <literal>--with-memcached</literal>
700 <para>&yaz; will be linked with
701 <ulink url="&url.libmemcached;">libMemcached</ulink> to allow
702 for result-set caching for ZOOM.
703 The prefix can not be given. Note that YAZ will only search
704 for libMemcached if Libgcrypt is also enabled.
705 Note that 0.40 of libmemcached is required.
711 <literal>--with-redis</literal>
714 <para>&yaz; will be linked with the hiredis C library
715 to allow for result-set caching for ZOOM on a
716 <ulink url="&url.redis;">redis</ulink> server.
717 The prefix can not be given. Note that YAZ will only search
718 for hiredis if Libgcrypt is also enabled.
726 When configured, build the software by typing:
732 The following files are generated by the make process:
735 <term><filename>src/libyaz.la</filename></term>
737 Main &yaz; library. This is no ordinary library. It's
739 By default, &yaz; creates a static library in
740 <filename>lib/.libs/libyaz.a</filename>.
744 <term><filename>src/libyaz_server.la</filename></term>
746 Generic Frontend server. This is an add-on for libyaz.la.
747 Code in this library uses POSIX threads functions - if POSIX
748 threads are available on the platform.
752 <term><filename>src/libyaz_icu.la</filename></term>
754 Functions that wrap the ICU library.
758 <term><filename>ztest/yaz-ztest</filename></term>
759 <listitem><para>Test Z39.50 server.
763 <term><filename>client/yaz-client</filename></term>
764 <listitem><para>Z39.50 client for testing the protocol.
765 See chapter <link linkend="yaz-client">
766 YAZ client</link> for more information.
770 <term><filename>util/yaz-config</filename></term>
771 <listitem><para>A Bourne-shell script, generated by configure, that
772 specifies how external applications should compile - and link with
777 <term><filename>util/yaz-asncomp</filename></term>
778 <listitem><para>The ASN.1 compiler for &yaz;. Requires the
779 Tcl Shell, <application>tclsh</application>, in
780 <literal>PATH</literal> to operate.
784 <term><filename>util/yaz-iconv</filename></term>
785 <listitem><para>This program converts data in one character set to
786 another. This command exercises the YAZ character set
791 <term><filename>util/yaz-marcdump</filename></term>
792 <listitem><para>This program parses ISO2709 encoded MARC records
793 and prints them in line-format or XML.
797 <term><filename>util/yaz-icu</filename></term>
798 <listitem><para>This program exposes the ICU wrapper library if that
799 is enabled for YAZ. Only if ICU is available this program is
804 <term><filename>util/yaz-url</filename></term>
805 <listitem><para>This program is a simple HTTP page fetcher ala
810 <term><filename>zoom/zoomsh</filename></term>
812 A simple shell implemented on top of the
813 <link linkend="zoom">ZOOM</link> functions.
814 The shell is a command line application that allows you to enter
815 simple commands to perform ZOOM operations.
819 <term><filename>zoom/zoomtst1</filename>,
820 <filename>zoom/zoomtst2</filename>, ..</term>
822 Several small applications that demonstrates the ZOOM API.
828 If you wish to install &yaz; in system directories
829 <filename>/usr/local/bin</filename>,
830 <filename>/usr/local/lib</filename> .. etc, you can type:
836 You probably need to have root access in order to perform this.
837 You must specify the <literal>--prefix</literal> option for configure if
838 you wish to install &yaz; in other directories than the default
839 <filename>/usr/local/</filename>.
842 If you wish to perform an un-installation of &yaz;, use:
848 This will only work if you haven't reconfigured &yaz; (and therefore
849 changed installation prefix). Note that uninstall will not
850 remove directories created by make install, e.g.
851 <filename>/usr/local/include/yaz</filename>.
854 <sect2 id="installation-linking-yaz-unix">
855 <title>How to make apps using YAZ on UNIX</title>
857 This section describes how to compile - and link your own
858 applications using the &yaz; toolkit.
859 If you're used to Makefiles this shouldn't be hard. As for
860 other libraries you have used before, you have to set a proper include
861 path for your C/C++ compiler and specify the location of
862 &yaz; libraries. You can do it by hand, but generally we suggest
863 you use the <filename>yaz-config</filename> that is generated
864 by <filename>configure</filename>. This is especially
865 important if you're using the threaded version of &yaz; which
866 require you to pass more options to your linker/compiler.
869 The <filename>yaz-config</filename> script accepts command line
870 options that makes the <filename>yaz-config</filename> script print
871 options that you should use in your make process.
872 The most important ones are:
873 <literal>--cflags</literal>, <literal>--libs</literal>
874 which prints C compiler flags, and linker flags respectively.
877 A small and complete <literal>Makefile</literal> for a C
878 application consisting of one source file,
879 <filename>myprog.c</filename>, may look like this:
881 YAZCONFIG=/usr/local/bin/yaz-config
882 CFLAGS=`$(YAZCONFIG) --cflags`
883 LIBS=`$(YAZCONFIG) --libs`
885 $(CC) $(CFLAGS) -o myprog myprog.o $(LIBS)
889 The CFLAGS variable consists of a C compiler directive that will set
890 the include path to the <emphasis>parent</emphasis> directory
891 of <filename>yaz</filename>. That is, if &yaz; header files were
892 installed in <filename>/usr/local/include/yaz</filename>,
893 then include path is set to <filename>/usr/local/include</filename>.
894 Therefore, in your applications you should use
896 #include <yaz/proto.h>
898 and <emphasis>not</emphasis>
900 #include <proto.h>
904 For Libtool users, the <filename>yaz-config</filename> script provides
905 a different variant of option <literal>--libs</literal>, called
906 <literal>--lalibs</literal> that returns the name of the
907 Libtool archive(s) for &yaz; rather than the ordinary ones.
910 For applications using the threaded version of &yaz;,
911 specify <literal>threads</literal> after the
912 other options. When <literal>threads</literal> is given,
913 more flags and linker flags will be printed by
914 <filename>yaz-config</filename>. If our previous example was
915 using threads, you'd have to modify the lines that set
916 <literal>CFLAGS</literal> and <literal>LIBS</literal> as
919 CFLAGS=`$(YAZCONFIG) --cflags threads`
920 LIBS=`$(YAZCONFIG) --libs threads`
922 There is no need specify POSIX thread libraries in your Makefile.
923 The <literal>LIBS</literal> variable includes that as well.
927 <sect1 id="installation.win32">
929 <para>The easiest way to install YAZ on Windows is by downloading
931 <ulink url="&url.yaz.download.win32;">here</ulink>.
932 The installer comes with source too - in case you wish to
933 compile YAZ with different compiler options, etc.
936 <sect2 id="installation.win32.source">
937 <title>Compiling from Source on WIN32</title>
939 &yaz; is shipped with "makefiles" for the NMAKE tool that comes
940 with <ulink url="&url.vstudio;">
941 Microsoft Visual Studio</ulink>. It has been tested with
942 Microsoft Visual Studio 2003/2005/2008/2013.
945 Start a command prompt and switch the sub directory
946 <filename>WIN</filename> where the file <filename>makefile</filename>
947 is located. Customize the installation by editing the
948 <filename>makefile</filename> file (for example by using notepad).
949 The following summarizes the most important settings in that file:
952 <term><literal>DEBUG</literal></term>
954 If set to 1, the software is
955 compiled with debugging libraries (code generation is
956 multi-threaded debug DLL).
957 If set to 0, the software is compiled with release libraries
958 (code generation is multi-threaded DLL).
962 <term><literal>HAVE_TCL</literal>, <literal>TCL</literal></term>
964 If <literal>HAVE_TCL</literal> is set to 1, nmake will
965 use the ASN.1 compiler (<ulink url="&url.tcl;">Tcl</ulink> based).
966 You must set <literal>TCL</literal> to the full path of the Tcl
967 interpreter. A Windows version of Tcl is part of
968 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
971 If you do not have Tcl installed, set
972 <literal>HAVE_TCL</literal> to 0.
976 <term><literal>HAVE_BISON</literal>,
977 <literal>BISON</literal></term>
979 If GNU Bison is present, you might set <literal>HAVE_BISON</literal>
980 to 1 and specify the Bison executable in <literal>BISON</literal>.
981 Bison is only required if you use the Git version of
982 YAZ or if you modify the grammar for CQL
983 (<filename>cql.y</filename>).
986 A Windows version of GNU Bison is part of
987 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
991 <term><literal>HAVE_ICONV</literal>,
992 <literal>ICONV_DIR</literal></term>
994 If <literal>HAVE_ICONV</literal> is set to 1, YAZ is compiled
995 with iconv support. In this configuration, set
996 <literal>ICONV_DIR</literal> to the iconv source directory.
1000 <term><literal>HAVE_LIBXML2</literal>,
1001 <literal>LIBXML2_DIR</literal></term>
1004 If <literal>HAVE_LIBXML2</literal> is set to 1, YAZ is compiled
1005 with SRU support. In this configuration, set
1006 <literal>LIBXML2_DIR</literal> to the
1007 <ulink url="&url.libxml2;">libxml2</ulink> source directory.
1010 You can get pre-compiled Libxml2+Libxslt DLLs and headers from
1011 <ulink url="&url.libxml2.download.windows;">here</ulink>.
1012 Should you with to compile those libraries yourself, refer to
1013 to <xref linkend="installation.windows.libxml2"/>
1018 <term><literal>HAVE_LIBXSLT</literal>,
1019 <literal>LIBXSLT_DIR</literal></term>
1022 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1023 with XSLT support. In this configuration, set
1024 <literal>LIBXSLT_DIR</literal> to the
1025 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1029 libxslt depends libxml2.
1035 <term><literal>HAVE_ICU</literal>,
1036 <literal>ICU_DIR</literal></term>
1039 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1040 with <ulink url="&url.icu;">ICU</ulink> support.
1041 In this configuration, set
1042 <literal>ICU_DIR</literal> to the
1043 <ulink url="&url.icu;">ICU</ulink> source directory.
1050 When satisfied with the settings in the makefile, type
1057 If the <filename>nmake</filename> command is not found on your system
1058 you probably haven't defined the environment variables required to
1059 use that tool. To fix that, find and run the batch file
1060 <filename>vcvars32.bat</filename>. You need to run it from within
1061 the command prompt or set the environment variables "globally";
1062 otherwise it doesn't work.
1066 If you wish to recompile &yaz; - for example if you modify
1067 settings in the <filename>makefile</filename> you can delete
1068 object files, etc by running.
1074 The following files are generated upon successful compilation:
1077 <term><filename>bin/yaz&soversion;.dll</filename> /
1078 <filename>bin/yaz&soversion;d.dll</filename></term>
1080 &yaz; Release/Debug DLL.
1084 <term><filename>lib/yaz&soversion;.lib</filename> /
1085 <filename>lib/yaz&soversion;d.lib</filename></term>
1087 Import library for <filename>yaz&soversion;.dll</filename> /
1088 <filename>yaz&soversion;d.dll</filename>.
1092 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1093 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1095 Release/Debug DLL for condition variable utilities (condvar.c).
1099 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1100 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1102 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1103 <filename>yaz_cond&soversion;d.dll</filename>.
1107 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1108 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1110 Release/Debug DLL for the ICU wrapper utility.
1111 Only build if HAVE_ICU is 1.
1115 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1116 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1118 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1119 <filename>yaz_icu&soversion;d.dll</filename>.
1123 <term><filename>bin/yaz-ztest.exe</filename></term>
1125 Z39.50 multi-threaded test/example server. It's a WIN32
1126 console application.
1130 <term><filename>bin/yaz-client.exe</filename></term>
1132 &yaz; Z39.50 client application. It's a WIN32 console application.
1133 See chapter <link linkend="yaz-client">YAZ client</link> for more
1138 <term><filename>bin/yaz-icu.exe</filename></term>
1139 <listitem><para>This program exposes the ICU wrapper library if that
1140 is enabled for YAZ. Only if ICU is available this program is
1145 <term><filename>bin/zoomsh.exe</filename></term>
1147 Simple console application implemented on top of the
1148 <link linkend="zoom">ZOOM</link> functions.
1149 The application is a command line shell that allows you to enter
1150 simple commands to perform ZOOM operations.
1154 <term><filename>bin/zoomtst1.exe</filename>,
1155 <filename>bin/zoomtst2.exe</filename>, ..</term>
1157 Several small applications that demonstrates the ZOOM API.
1164 <sect2 id="installation-linking-yaz-win32">
1165 <title>How to make apps using YAZ on Windows</title>
1167 This section will go though the process of linking your Windows
1168 applications with &yaz;.
1171 Some people are confused by the fact that we use the nmake
1172 tool to build &yaz;. They think they have to do that too - in order
1173 to make their Windows applications work with &yaz;. The good news is that
1174 you don't have to. You can use the integrated environment of
1175 Visual Studio if desired for your own application.
1178 When setting up a project or Makefile you have to set the following:
1181 <term>include path</term>
1183 Set it to the <filename>include</filename> directory of &yaz;.
1187 <term>import library <filename>yaz&soversion;.lib</filename></term>
1189 You must link with this library. It's located in the
1190 sub directory <filename>lib</filename> of &yaz;.
1191 If you want to link with the debug version of &yaz;, you must
1192 link against <filename>yaz&soversion;d.lib</filename> instead.
1196 <term>dynamic link library
1197 <filename>yaz&soversion;.dll</filename>
1200 This DLL must be in your execution path when you invoke
1201 your application. Specifically, you should distribute this
1202 DLL with your application.
1209 <sect2 id="installation.windows.libxml2">
1210 <title>Compiling Libxml2 and Libxslt on windows</title>
1212 Download libxml2 and Libxslt source and unpack it.
1213 In the example below we install Libxml2 2.9.2 and Libxslt 1.1.28
1214 for 32-bit, so we use the destination directories
1215 libxml2.2.9.2.win32 and libxslt-1.1.28.win32 to reflect both
1216 version and architecture.
1219 cscript configure.js prefix=c:\libxml2-2.9.2.win32 iconv=no
1225 For Libxslt it is similar. We must ensure that compilation of
1226 Libxslt links against the already installed libxml2.
1229 cscript configure.js prefix=c:\libxslt-1.1.28.win32 iconv=no \
1230 lib=c:\libxmlt-2.9.2.win32\lib \
1231 include=c:\libxmlt-2.9.2.win32\include\libxml2
1241 ### Still to document:
1242 ZOOM_connection_errcode(c)
1243 ZOOM_connection_errmsg(c)
1244 ZOOM_connection_addinfo(c)
1245 ZOOM_connection_addinfo(c)
1246 ZOOM_connection_diagset(c);
1247 ZOOM_connection_save_apdu_wrbuf
1248 ZOOM_diag_str(error)
1249 ZOOM_resultset_record_immediate(s, pos)
1250 ZOOM_resultset_cache_reset(r)
1251 ZOOM_options_set_callback(opt, function, handle)
1252 ZOOM_options_create_with_parent2(parent1, parent2)
1253 ZOOM_options_getl(opt, name, len)
1254 ZOOM_options_setl(opt, name, value, len)
1255 ZOOM_options_get_bool(opt, name, defa)
1256 ZOOM_options_get_int(opt, name, defa)
1257 ZOOM_options_set_int(opt, name, value)
1262 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1263 an initiative started by Mike Taylor (Mike is from the UK, which
1264 explains the peculiar name of the model). The goal of &zoom; is to
1265 provide a common Z39.50 client API not bound to a particular
1266 programming language or toolkit.
1269 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1270 You can make SRU ZOOM connections by specifying scheme
1271 <literal>http://</literal> for the hostname for a connection.
1272 The dialect of SRU used is specified by the value of the
1273 connection's <literal>sru</literal> option, which may be SRU over
1274 HTTP GET (<literal>get</literal>),
1275 SRU over HTTP POST (<literal>post</literal>), (SRU over
1276 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1277 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1278 Using the facility for embedding options in target strings, a
1279 connection can be forced to use SRU rather the SRW (the default) by
1280 prefixing the target string with <literal>sru=get,</literal>, like this:
1281 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1284 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1285 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1286 HTTP based protocols.
1289 The lack of a simple Z39.50 client API for &yaz; has become more
1290 and more apparent over time. So when the first &zoom; specification
1292 an implementation for &yaz; was quickly developed. For the first time, it is
1293 now as easy (or easier!) to develop clients than servers with &yaz;. This
1294 chapter describes the &zoom; C binding. Before going further, please
1295 reconsider whether C is the right programming language for the job.
1296 There are other language bindings available for &yaz;, and still
1298 are in active development. See the
1299 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1303 In order to fully understand this chapter you should read and
1304 try the example programs <literal>zoomtst1.c</literal>,
1305 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1309 The C language misses features found in object oriented languages
1310 such as C++, Java, etc. For example, you'll have to manually,
1311 destroy all objects you create, even though you may think of them as
1312 temporary. Most objects has a <literal>_create</literal> - and a
1313 <literal>_destroy</literal> variant.
1314 All objects are in fact pointers to internal stuff, but you don't see
1315 that because of typedefs. All destroy methods should gracefully ignore a
1316 <literal>NULL</literal> pointer.
1319 In each of the sections below you'll find a sub section called
1320 protocol behavior, that describes how the API maps to the Z39.50
1323 <sect1 id="zoom-connections">
1324 <title>Connections</title>
1325 <para>The Connection object is a session with a target.
1328 #include <yaz/zoom.h>
1330 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1332 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1334 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1336 void ZOOM_connection_destroy(ZOOM_connection c);
1339 Connection objects are created with either function
1340 <function>ZOOM_connection_new</function> or
1341 <function>ZOOM_connection_create</function>.
1342 The former creates and automatically attempts to establish a network
1343 connection with the target. The latter doesn't establish
1344 a connection immediately, thus allowing you to specify options
1345 before establishing network connection using the function
1346 <function>ZOOM_connection_connect</function>.
1347 If the port number, <literal>portnum</literal>, is zero, the
1348 <literal>host</literal> is consulted for a port specification.
1349 If no port is given, 210 is used. A colon denotes the beginning of
1350 a port number in the host string. If the host string includes a
1351 slash, the following part specifies a database for the connection.
1354 You can prefix the host with a scheme followed by colon. The
1355 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1356 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1357 but can overridded to use SRU/post, SRW and the Solr protocol.
1360 You can prefix the scheme-qualified host-string with one or more
1362 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1363 sequences, each of which represents an option to be set into the
1364 connection structure <emphasis>before</emphasis> the
1365 protocol-level connection is forged and the initialization
1366 handshake takes place. This facility can be used to provide
1367 authentication credentials, as in host-strings such as:
1368 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1371 Connection objects should be destroyed using the function
1372 <function>ZOOM_connection_destroy</function>.
1375 void ZOOM_connection_option_set(ZOOM_connection c,
1376 const char *key, const char *val);
1378 void ZOOM_connection_option_setl(ZOOM_connection c,
1380 const char *val, int len);
1382 const char *ZOOM_connection_option_get(ZOOM_connection c,
1384 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1389 The functions <function>ZOOM_connection_option_set</function> and
1390 <function>ZOOM_connection_option_setl</function> allows you to
1391 set an option given by <parameter>key</parameter> to the value
1392 <parameter>value</parameter> for the connection.
1393 For <function>ZOOM_connection_option_set</function>, the
1394 value is assumed to be a 0-terminated string. Function
1395 <function>ZOOM_connection_option_setl</function> specifies a
1396 value of a certain size (len).
1399 Functions <function>ZOOM_connection_option_get</function> and
1400 <function>ZOOM_connection_option_getl</function> returns
1401 the value for an option given by <parameter>key</parameter>.
1403 <table id="zoom-connection-options" frame="top">
1404 <title>ZOOM Connection Options</title>
1406 <colspec colwidth="4*" colname="name"></colspec>
1407 <colspec colwidth="7*" colname="description"></colspec>
1408 <colspec colwidth="3*" colname="default"></colspec>
1411 <entry>Option</entry>
1412 <entry>Description</entry>
1413 <entry>Default</entry>
1418 implementationName</entry><entry>Name of Your client
1419 </entry><entry>none</entry></row>
1421 user</entry><entry>Authentication user name
1422 </entry><entry>none</entry></row>
1424 group</entry><entry>Authentication group name
1425 </entry><entry>none</entry></row>
1427 password</entry><entry>Authentication password.
1428 </entry><entry>none</entry></row>
1430 authenticationMode</entry><entry>How authentication is encoded.
1431 </entry><entry>basic</entry></row>
1433 host</entry><entry>Target host. This setting is "read-only".
1434 It's automatically set internally when connecting to a target.
1435 </entry><entry>none</entry></row>
1437 proxy</entry><entry>Proxy host. If set, the logical host
1438 is encoded in the otherInfo area of the Z39.50 Init PDU
1439 with OID 1.2.840.10003.10.1000.81.1.
1440 </entry><entry>none</entry></row>
1442 clientIP</entry><entry>Client IP. If set, is
1443 encoded in the otherInfo area of a Z39.50 PDU with OID
1444 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1445 of a client. Is used of ZOOM is used in a gateway of some sort.
1446 </entry><entry>none</entry></row>
1448 async</entry><entry>If true (1) the connection operates in
1449 asynchronous operation which means that all calls are non-blocking
1451 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1452 </entry><entry>0</entry></row>
1454 maximumRecordSize</entry><entry> Maximum size of single record.
1455 </entry><entry>1 MB</entry></row>
1457 preferredMessageSize</entry><entry> Maximum size of multiple records.
1458 </entry><entry>1 MB</entry></row>
1460 lang</entry><entry> Language for negotiation.
1461 </entry><entry>none</entry></row>
1463 charset</entry><entry> Character set for negotiation.
1464 </entry><entry>none</entry></row>
1466 serverImplementationId</entry><entry>
1467 Implementation ID of server. (The old targetImplementationId
1468 option is also supported for the benefit of old applications.)
1469 </entry><entry>none</entry></row>
1471 targetImplementationName</entry><entry>
1472 Implementation Name of server. (The old
1473 targetImplementationName option is also supported for the
1474 benefit of old applications.)
1475 </entry><entry>none</entry></row>
1477 serverImplementationVersion</entry><entry>
1478 Implementation Version of server. (the old
1479 targetImplementationVersion option is also supported for the
1480 benefit of old applications.)
1481 </entry><entry>none</entry></row>
1483 databaseName</entry><entry>One or more database names
1484 separated by character plus (<literal>+</literal>), which to
1485 be used by subsequent search requests on this Connection.
1486 </entry><entry>Default</entry></row>
1488 piggyback</entry><entry>True (1) if piggyback should be
1489 used in searches; false (0) if not.
1490 </entry><entry>1</entry></row>
1492 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1493 value, then target will return all records using small element set name
1494 </entry><entry>0</entry></row>
1496 largeSetLowerBound</entry><entry>If hits is greater than this
1497 value, the target will return no records.
1498 </entry><entry>1</entry></row>
1500 mediumSetPresentNumber</entry><entry>This value represents
1501 the number of records to be returned as part of a search when when
1502 hits is less than or equal to large set lower bound and if hits
1503 is greater than small set upper bound.
1504 </entry><entry>0</entry></row>
1506 smallSetElementSetName</entry><entry>
1507 The element set name to be used for small result sets.
1508 </entry><entry>none</entry></row>
1510 mediumSetElementSetName</entry><entry>
1511 The element set name to be for medium-sized result sets.
1512 </entry><entry>none</entry></row>
1514 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1515 After a successful Init, these options may be interrogated to
1516 discover whether the server claims to support the specified
1518 </entry><entry>none</entry></row>
1520 <entry>sru</entry><entry>
1521 SRU/Solr transport type. Must be either <literal>soap</literal>,
1522 <literal>get</literal>, <literal>post</literal>, or
1523 <literal>solr</literal>.
1524 </entry><entry>soap</entry></row>
1526 sru_version</entry><entry>
1527 SRU/SRW version. Should be <literal>1.1</literal>, or
1528 <literal>1.2</literal>. This is , prior to connect, the version
1529 to offer (highest version). And following connect (in fact
1530 first operation), holds the negotiated version with the server
1531 (same or lower version).
1532 </entry><entry>1.2</entry></row>
1533 <row id="zoom.facets.option"><entry>
1534 facets</entry><entry>
1535 Requested or recommend facets may be given before a search is sent.
1536 The value of this setting is described in <xref linkend="facets"/>
1537 For inspection of the facets returned, refer to the functions
1538 described in <xref linkend="zoom.facets"/>.
1539 </entry><entry>none</entry></row>
1541 apdulog</entry><entry>
1542 If set to a true value such as "1", a log of low-level
1543 protocol packets is emitted on standard error stream. This
1544 can be very useful for debugging.
1545 </entry><entry>0</entry></row>
1547 saveAPDU</entry><entry>
1548 If set to a true value such as "1", a log of low-level
1549 protocol packets is saved. The log can be retrieved by reading
1550 option APDU. Setting saveAPDU always has the side effect of
1551 resetting the currently saved log. This setting is
1552 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1553 It is only recognized in
1554 <function>ZOOM_connection_option_set</function>.
1555 </entry><entry>0</entry></row>
1558 Returns the log of protocol packets. Will be empty if logging
1559 is not enabled (see saveAPDU above). This setting is
1560 <emphasis>read-only</emphasis>. It is only recognized if used
1561 in call to <function>ZOOM_connection_option_get</function> or
1562 <function>ZOOM_connection_option_getl</function>.
1563 </entry><entry></entry></row>
1565 memcached</entry><entry>
1566 If given and non-empty,
1567 <ulink url="&url.libmemcached;">libMemcached</ulink>
1568 will be configured for the connection.
1569 This option is inspected by ZOOM when a connection is established.
1570 If the <literal>memcached</literal> option is given
1571 and YAZ is compiled without libMemcached support, an internal
1572 diagnostic (10018) will be thrown.
1573 libMemcached support is available for YAZ 5.0.13 or later. If this
1574 option is supplied for an earlier version of YAZ, it is
1575 <emphasis>ignored</emphasis>.
1576 The value of this option is a list options - each is of the
1577 form <literal>--name=value</literal>.
1578 Option <literal>--server=</literal>host[:port] specifies a memcached
1579 server. It may be repeated for multiple memcached servers.
1580 Option <literal>--expire=</literal>seconds sets expiry time in seconds
1581 for how long result sets are to be cached.
1582 </entry><entry>none</entry></row>
1584 redis</entry><entry>
1585 If given and non-empty,
1586 a <ulink url="&url.redis;">redis</ulink> context will be created
1588 This option is inspected by ZOOM when a connection is established.
1589 If the <literal>redis</literal> option is given
1590 and YAZ is compiled without redis support, an internal
1591 diagnostic (10018) will be thrown.
1592 redis support is available for YAZ 5.2.0 or later. If this
1593 option is supplied for an earlier version of YAZ, it is
1594 <emphasis>ignored</emphasis>.
1595 The value of this option is a set options, similar to that
1596 of the memcached setting. At this stage only --server=host[:port]
1597 and --expire=seconds is supported.
1598 </entry><entry>none</entry></row>
1603 If either option <literal>lang</literal> or <literal>charset</literal>
1605 <ulink url="&url.z39.50.charneg;">
1606 Character Set and Language Negotiation</ulink> is in effect.
1609 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1610 const char **addinfo);
1611 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1612 const char **addinfo, const char **dset);
1615 Function <function>ZOOM_connection_error</function> checks for
1616 errors for the last operation(s) performed. The function returns
1617 zero if no errors occurred; non-zero otherwise indicating the error.
1618 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1619 holds messages for the error and additional-info if passed as
1620 non-<literal>NULL</literal>. Function
1621 <function>ZOOM_connection_error_x</function> is an extended version
1622 of <function>ZOOM_connection_error</function> that is capable of
1623 returning name of diagnostic set in <parameter>dset</parameter>.
1625 <sect2 id="zoom-connection-z39.50">
1626 <title>Z39.50 Protocol behavior</title>
1628 The calls <function>ZOOM_connection_new</function> and
1629 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1630 connection and sends an Initialize Request to the target if
1631 possible. In addition, the calls waits for an Initialize Response
1632 from the target and the result is inspected (OK or rejected).
1635 If <literal>proxy</literal> is set then the client will establish
1636 a TCP/IP connection with the peer as specified by the
1637 <literal>proxy</literal> host and the hostname as part of the
1638 connect calls will be set as part of the Initialize Request.
1639 The proxy server will then "forward" the PDU's transparently
1640 to the target behind the proxy.
1643 For the authentication parameters, if option <literal>user</literal>
1644 is set and both options <literal>group</literal> and
1645 <literal>pass</literal> are unset, then Open style
1646 authentication is used (Version 2/3) in which case the username
1647 is usually followed by a slash, then by a password.
1648 If either <literal>group</literal>
1649 or <literal>pass</literal> is set then idPass authentication
1650 (Version 3 only) is used. If none of the options are set, no
1651 authentication parameters are set as part of the Initialize Request
1655 When option <literal>async</literal> is 1, it really means that
1656 all network operations are postponed (and queued) until the
1657 function <literal>ZOOM_event</literal> is invoked. When doing so
1658 it doesn't make sense to check for errors after
1659 <literal>ZOOM_connection_new</literal> is called since that
1660 operation "connecting - and init" is still incomplete and the
1661 API cannot tell the outcome (yet).
1664 <sect2 id="zoom.sru.init.behavior">
1665 <title>SRU/Solr Protocol behavior</title>
1667 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1668 Inititialize Request, so the connection phase merely establishes a
1669 TCP/IP connection with the HTTP server.
1671 <para>Most of the ZOOM connection options do not
1672 affect SRU/Solr and they are ignored. However, future versions
1673 of &yaz; might honor <literal>implementationName</literal> and
1674 put that as part of User-Agent header for HTTP requests.
1677 The <literal>charset</literal> is used in the Content-Type header
1681 Setting <literal>authentcationMode</literal> specifies how
1682 authentication parameters are encoded for HTTP. The default is
1683 "<literal>basic</literal>" where <literal>user</literal> and
1684 <literal>password</literal> are encoded by using HTTP basic
1688 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1689 user and password are encoded in the URL by parameters
1690 <literal>x-username</literal> and <literal>x-password</literal> as
1691 given by the SRU standard.
1695 <sect1 id="zoom.query">
1696 <title>Queries</title>
1698 Query objects represents queries.
1701 ZOOM_query ZOOM_query_create(void);
1703 void ZOOM_query_destroy(ZOOM_query q);
1705 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1707 int ZOOM_query_cql(ZOOM_query s, const char *str);
1709 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1711 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1712 const char *criteria);
1715 Create query objects using <function>ZOOM_query_create</function>
1716 and destroy them by calling <function>ZOOM_query_destroy</function>.
1717 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1718 notation by using the
1719 function <function>ZOOM_query_prefix</function>.
1720 The <function>ZOOM_query_cql</function> specifies a CQL
1721 query to be sent to the server/target.
1722 More query types will be added in future versions of &yaz;, such as
1723 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1724 etc. In addition to a search, a sort criteria may be set. Function
1725 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1726 it takes sort criteria using the same string notation as
1727 yaz-client's <link linkend="sortspec">sort command</link>.
1729 <para id="zoom.query.sortby2">
1730 <function>ZOOM_query_sortby2</function> is similar to
1731 <function>ZOOM_query_sortby</function> but allows a strategy for
1732 sorting. The reason for the strategy parameter is that some
1733 protocols offers multiple ways of performing sorting.
1734 For example, Z39.50 has the standard sort, which is performed after
1735 search on an existing result set.
1736 It's also possible to use CQL in Z39.50 as the query type and use
1737 CQL's SORTBY keyword. Finally, Index Data's
1738 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1740 <table id="zoom-sort-strategy" frame="top">
1741 <title>ZOOM sort strategy</title>
1743 <colspec colwidth="2*" colname="name"/>
1744 <colspec colwidth="5*" colname="description"/>
1748 <entry>Description</entry>
1753 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1756 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1759 <entry>cql</entry><entry>CQL SORTBY</entry>
1762 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1765 <entry>solr</entry><entry>Solr sort</entry>
1768 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1769 solr for Solr protocol</entry>
1775 <sect1 id="zoom.resultsets"><title>Result sets</title>
1777 The result set object is a container for records returned from
1781 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1783 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1785 void ZOOM_resultset_destroy(ZOOM_resultset r);
1788 Function <function>ZOOM_connection_search</function> creates
1789 a result set given a connection and query.
1790 Destroy a result set by calling
1791 <function>ZOOM_resultset_destroy</function>.
1792 Simple clients may using PQF only may use function
1793 <function>ZOOM_connection_search_pqf</function> in which case
1794 creating query objects is not necessary.
1797 void ZOOM_resultset_option_set(ZOOM_resultset r,
1798 const char *key, const char *val);
1800 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1802 size_t ZOOM_resultset_size(ZOOM_resultset r);
1805 Functions <function>ZOOM_resultset_options_set</function> and
1806 <function>ZOOM_resultset_get</function> sets and gets an option
1807 for a result set similar to <function>ZOOM_connection_option_get</function>
1808 and <function>ZOOM_connection_option_set</function>.
1811 The number of hits also called result-count is returned by
1812 function <function>ZOOM_resultset_size</function>.
1814 <table id="zoom.resultset.options"
1815 frame="top"><title>ZOOM Result set Options</title>
1817 <colspec colwidth="4*" colname="name"></colspec>
1818 <colspec colwidth="7*" colname="description"></colspec>
1819 <colspec colwidth="2*" colname="default"></colspec>
1822 <entry>Option</entry>
1823 <entry>Description</entry>
1824 <entry>Default</entry>
1829 start</entry><entry>Offset of first record to be
1830 retrieved from target. First record has offset 0 unlike the
1831 protocol specifications where first record has position 1.
1832 This option affects ZOOM_resultset_search and
1833 ZOOM_resultset_search_pqf and must be set before any of
1834 these functions are invoked. If a range of
1835 records must be fetched manually after search,
1836 function ZOOM_resultset_records should be used.
1837 </entry><entry>0</entry></row>
1839 count</entry><entry>Number of records to be retrieved.
1840 This option affects ZOOM_resultset_search and
1841 ZOOM_resultset_search_pqf and must be set before any of
1842 these functions are invoked.
1843 </entry><entry>0</entry></row>
1845 presentChunk</entry><entry>The number of records to be
1846 requested from the server in each chunk (present request). The
1847 value 0 means to request all the records in a single chunk.
1848 (The old <literal>step</literal>
1849 option is also supported for the benefit of old applications.)
1850 </entry><entry>0</entry></row>
1852 elementSetName</entry><entry>Element-Set name of records.
1853 Most targets should honor element set name <literal>B</literal>
1854 and <literal>F</literal> for brief and full respectively.
1855 </entry><entry>none</entry></row>
1857 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1858 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1859 </entry><entry>none</entry></row>
1861 schema</entry><entry>Schema for retrieval, such as
1862 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1863 </entry><entry>none</entry></row>
1865 setname</entry><entry>Name of Result Set (Result Set ID).
1866 If this option isn't set, the ZOOM module will automatically
1867 allocate a result set name.
1868 </entry><entry>default</entry></row>
1870 rpnCharset</entry><entry>Character set for RPN terms.
1871 If this is set, ZOOM C will assume that the ZOOM application is
1872 running UTF-8. Terms in RPN queries are then converted to the
1873 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1874 of RPN terms and no conversion is performed.
1875 </entry><entry>none</entry></row>
1880 For servers that support Search Info report, the following
1881 options may be read using <function>ZOOM_resultset_get</function>.
1882 This detailed information is read after a successful search has
1886 This information is a list of of items, where each item is
1887 information about a term or subquery. All items in the list
1889 <literal>SearchResult.</literal><replaceable>no</replaceable>
1890 where no presents the item number (0=first, 1=second).
1891 Read <literal>searchresult.size</literal> to determine the
1894 <table id="zoom.search.info.report.options"
1895 frame="top"><title>Search Info Report Options</title>
1897 <colspec colwidth="4*" colname="name"></colspec>
1898 <colspec colwidth="7*" colname="description"></colspec>
1901 <entry>Option</entry>
1902 <entry>Description</entry>
1907 <entry>searchresult.size</entry>
1909 number of search result entries. This option is-nonexistant
1910 if no entries are returned by the server.
1914 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1915 <entry>sub query ID</entry>
1918 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1919 <entry>result count for item (number of hits)</entry>
1922 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1923 <entry>subquery term</entry>
1927 searchresult.<replaceable>no</replaceable>.interpretation.term
1929 <entry>interpretation term</entry>
1933 searchresult.<replaceable>no</replaceable>.recommendation.term
1935 <entry>recommendation term</entry>
1940 <sect2 id="zoom.z3950.resultset.sort">
1941 <title>Z39.50 Result-set Sort</title>
1943 void ZOOM_resultset_sort(ZOOM_resultset r,
1944 const char *sort_type, const char *sort_spec);
1946 int ZOOM_resultset_sort1(ZOOM_resultset r,
1947 const char *sort_type, const char *sort_spec);
1950 <function>ZOOM_resultset_sort</function> and
1951 <function>ZOOM_resultset_sort1</function> both sort an existing
1952 result-set. The sort_type parameter is not use. Set it to "yaz".
1953 The sort_spec is same notation as ZOOM_query_sortby and identical
1954 to that offered by yaz-client's
1955 <link linkend="sortspec">sort command</link>.
1958 These functions only work for Z39.50. Use the more generic utility
1959 <link linkend="zoom.query.sortby2">
1960 <function>ZOOM_query_sortby2</function></link>
1961 for other protocols (and even Z39.50).
1964 <sect2 id="zoom.z3950.resultset.behavior">
1965 <title>Z39.50 Protocol behavior</title>
1967 The creation of a result set involves at least a SearchRequest
1968 - SearchResponse protocol handshake. Following that, if a sort
1969 criteria was specified as part of the query, a SortRequest -
1970 SortResponse handshake takes place. Note that it is necessary to
1971 perform sorting before any retrieval takes place, so no records will
1972 be returned from the target as part of the SearchResponse because these
1973 would be unsorted. Hence, piggyback is disabled when sort criteria
1974 are set. Following Search - and a possible sort - Retrieval takes
1975 place - as one or more Present Requests/Response pairs being
1979 The API allows for two different modes for retrieval. A high level
1980 mode which is somewhat more powerful and a low level one.
1981 The low level is enabled when searching on a Connection object
1982 for which the settings
1983 <literal>smallSetUpperBound</literal>,
1984 <literal>mediumSetPresentNumber</literal> and
1985 <literal>largeSetLowerBound</literal> are set. The low level mode
1986 thus allows you to precisely set how records are returned as part
1987 of a search response as offered by the Z39.50 protocol.
1988 Since the client may be retrieving records as part of the
1989 search response, this mode doesn't work well if sorting is used.
1992 The high-level mode allows you to fetch a range of records from
1993 the result set with a given start offset. When you use this mode
1994 the client will automatically use piggyback if that is possible
1995 with the target and perform one or more present requests as needed.
1996 Even if the target returns fewer records as part of a present response
1997 because of a record size limit, etc. the client will repeat sending
1998 present requests. As an example, if option <literal>start</literal>
1999 is 0 (default) and <literal>count</literal> is 4, and
2000 <literal>piggyback</literal> is 1 (default) and no sorting criteria
2001 is specified, then the client will attempt to retrieve the 4
2002 records as part the search response (using piggyback). On the other
2003 hand, if either <literal>start</literal> is positive or if
2004 a sorting criteria is set, or if <literal>piggyback</literal>
2005 is 0, then the client will not perform piggyback but send Present
2009 If either of the options <literal>mediumSetElementSetName</literal> and
2010 <literal>smallSetElementSetName</literal> are unset, the value
2011 of option <literal>elementSetName</literal> is used for piggyback
2012 searches. This means that for the high-level mode you only have
2013 to specify one elementSetName option rather than three.
2016 <sect2 id="zoom.sru.resultset.behavior">
2017 <title>SRU Protocol behavior</title>
2019 Current version of &yaz; does not take advantage of a result set id
2020 returned by the SRU server. Future versions might do, however.
2021 Since, the ZOOM driver does not save result set IDs any
2022 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2023 with same query but, possibly, different offsets.
2026 Option <literal>schema</literal> specifies SRU schema
2027 for retrieval. However, options <literal>elementSetName</literal> and
2028 <literal>preferredRecordSyntax</literal> are ignored.
2031 Options <literal>start</literal> and <literal>count</literal>
2032 are supported by SRU.
2033 The remaining options
2034 <literal>piggyback</literal>,
2035 <literal>smallSetUpperBound</literal>,
2036 <literal>largeSetLowerBound</literal>,
2037 <literal>mediumSetPresentNumber</literal>,
2038 <literal>mediumSetElementSetName</literal>,
2039 <literal>smallSetElementSetName</literal> are
2043 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2044 If PQF is used, however, the PQF query is transferred anyway
2045 using non-standard element <literal>pQuery</literal> in
2046 SRU SearchRetrieveRequest.
2049 Solr queries has to be done in Solr query format.
2052 Unfortunately, SRU or Solr does not define a database setting. Hence,
2053 <literal>databaseName</literal> is unsupported and ignored.
2054 However, the path part in host parameter for functions
2055 <function>ZOOM_connecton_new</function> and
2056 <function>ZOOM_connection_connect</function> acts as a
2057 database (at least for the &yaz; SRU server).
2061 <sect1 id="zoom.records">
2062 <title>Records</title>
2064 A record object is a retrieval record on the client side -
2065 created from result sets.
2068 void ZOOM_resultset_records(ZOOM_resultset r,
2070 size_t start, size_t count);
2071 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2073 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2076 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2077 const char **addinfo, const char **diagset);
2079 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2081 void ZOOM_record_destroy(ZOOM_record rec);
2084 References to temporary records are returned by functions
2085 <function>ZOOM_resultset_records</function> or
2086 <function>ZOOM_resultset_record</function>.
2089 If a persistent reference to a record is desired
2090 <function>ZOOM_record_clone</function> should be used.
2091 It returns a record reference that should be destroyed
2092 by a call to <function>ZOOM_record_destroy</function>.
2095 A single record is returned by function
2096 <function>ZOOM_resultset_record</function> that takes a
2097 position as argument. First record has position zero.
2098 If no record could be obtained <literal>NULL</literal> is returned.
2101 Error information for a record can be checked with
2102 <function>ZOOM_record_error</function> which returns non-zero
2103 (error code) if record is in error, called <emphasis>Surrogate
2104 Diagnostics</emphasis> in Z39.50.
2107 Function <function>ZOOM_resultset_records</function> retrieves
2108 a number of records from a result set. Parameter <literal>start</literal>
2109 and <literal>count</literal> specifies the range of records to
2110 be returned. Upon completion array
2111 <literal>recs[0], ..recs[count-1]</literal>
2112 holds record objects for the records. The array of records
2113 <literal>recs</literal> should be allocated prior the call
2114 <function>ZOOM_resultset_records</function>. Note that for those
2115 records that couldn't be retrieved from the target
2116 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2118 <para id="zoom.record.get">
2119 In order to extract information about a single record,
2120 <function>ZOOM_record_get</function> is provided. The
2121 function returns a pointer to certain record information. The
2122 nature (type) of the pointer depends on the parameter,
2123 <parameter>type</parameter>.
2126 The <parameter>type</parameter> is a string of the format:
2129 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>]
2132 where <replaceable>format</replaceable> specifies the format of the
2133 returned record, <replaceable>from</replaceable>
2134 specifies the character set of the record in its original form
2135 (as returned by the server), <replaceable>to</replaceable> specifies
2136 the output (returned)
2137 character set encoding.
2138 If <replaceable>to</replaceable> is omitted UTF-8 is assumed.
2139 If charset is not given, then no character set conversion takes place.
2142 <para>OPAC records may be returned in a different
2143 set from the bibliographic MARC record. If this is this the case,
2144 <replaceable>opacfrom</replaceable> should be set to the character set
2145 of the OPAC record part.
2149 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2153 The format argument controls whether record data should be XML
2154 pretty-printed (post process operation).
2155 It is enabled only if format value <replaceable>v</replaceable> is
2156 <literal>1</literal> and the record content is XML well-formed.
2159 In addition, for certain types, the length
2160 <literal>len</literal> passed will be set to the size in bytes of
2161 the returned information.
2164 The following are the supported values for <replaceable>form</replaceable>.
2166 <varlistentry><term><literal>database</literal></term>
2167 <listitem><para>Database of record is returned
2168 as a C null-terminated string. Return type
2169 <literal>const char *</literal>.
2172 <varlistentry><term><literal>syntax</literal></term>
2173 <listitem><para>The transfer syntax of the record is returned
2174 as a C null-terminated string containing the symbolic name of
2175 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2177 <literal>const char *</literal>.
2180 <varlistentry><term><literal>schema</literal></term>
2181 <listitem><para>The schema of the record is returned
2182 as a C null-terminated string. Return type is
2183 <literal>const char *</literal>.
2186 <varlistentry><term><literal>render</literal></term>
2187 <listitem><para>The record is returned in a display friendly
2188 format. Upon completion buffer is returned
2189 (type <literal>const char *</literal>) and length is stored in
2190 <literal>*len</literal>.
2193 <varlistentry><term><literal>raw</literal></term>
2194 <listitem><para>The record is returned in the internal
2195 YAZ specific format. For GRS-1, Explain, and others, the
2196 raw data is returned as type
2197 <literal>Z_External *</literal> which is just the type for
2198 the member <literal>retrievalRecord</literal> in
2199 type <literal>NamePlusRecord</literal>.
2200 For SUTRS and octet aligned record (including all MARCs) the
2201 octet buffer is returned and the length of the buffer.
2204 <varlistentry><term><literal>xml</literal></term>
2205 <listitem><para>The record is returned in XML if possible.
2206 SRU, Solr and Z39.50 records with transfer syntax XML are
2207 returned verbatim. MARC records are returned in
2208 <ulink url="&url.marcxml;">
2211 (converted from ISO2709 to MARCXML by YAZ).
2212 OPAC records are also converted to XML and the
2213 bibliographic record is converted to MARCXML (when possible).
2214 GRS-1 records are not supported for this form.
2215 Upon completion, the XML buffer is returned
2216 (type <literal>const char *</literal>) and length is stored in
2217 <literal>*len</literal>.
2220 <varlistentry><term><literal>opac</literal></term>
2221 <listitem><para>OPAC information for record is returned in XML
2222 if an OPAC record is present at the position given. If no
2223 OPAC record is present, a NULL pointer is returned.
2226 <varlistentry><term><literal>txml</literal></term>
2227 <listitem><para>The record is returned in TurboMARC if possible.
2228 SRU and Z39.50 records with transfer syntax XML are
2229 returned verbatim. MARC records are returned in
2230 <link linkend="tools.turbomarc">
2233 (converted from ISO2709 to TurboMARC by YAZ).
2234 Upon completion, the XML buffer is returned
2235 (type <literal>const char *</literal>) and length is stored in
2236 <literal>*len</literal>.
2239 <varlistentry><term><literal>json</literal></term>
2240 <listitem><para>Like xml, but MARC records are converted to
2241 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2249 <ulink url="&url.marc21;">MARC21</ulink>
2251 <ulink url="&url.marc8;">MARC-8</ulink>
2252 character set encoding.
2253 An application that wishes to display in Latin-1 would use
2255 render; charset=marc8,iso-8859-1
2258 <sect2 id="zoom.z3950.record.behavior">
2259 <title>Z39.50 Protocol behavior</title>
2261 The functions <function>ZOOM_resultset_record</function> and
2262 <function>ZOOM_resultset_records</function> inspects the client-side
2263 record cache. Records not found in cache are fetched using
2265 The functions may block (and perform network I/O) - even though option
2266 <literal>async</literal> is 1, because they return records objects.
2267 (and there's no way to return records objects without retrieving them!).
2270 There is a trick, however, in the usage of function
2271 <function>ZOOM_resultset_records</function> that allows for
2272 delayed retrieval (and makes it non-blocking). By using
2273 a null pointer for <parameter>recs</parameter> you're indicating
2274 you're not interested in getting records objects
2275 <emphasis>now</emphasis>.
2278 <sect2 id="zoom.sru.record.behavior">
2279 <title>SRU/Solr Protocol behavior</title>
2281 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2282 as if they where Z39.50 records with transfer syntax XML and
2283 no element set name or database name.
2287 <sect1 id="zoom.facets"><title>Facets</title>
2289 Facet operations is not part of the official ZOOM specification, but
2290 is an Index Data extension for YAZ-based Z39.50 targets,
2291 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2293 Facets may be requestd by the
2294 <link linkend="zoom.facets.option">facets</link> option before a
2296 For inspection of the returned facets, the following functions are
2300 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2302 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2303 const char *facet_name);
2305 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2308 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2310 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2312 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2314 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2315 size_t idx, int *freq);
2318 References to temporary structures are returned by all functions.
2319 They are only valid as long the Result set is valid.
2320 <function>ZOOM_resultset_get_facet_field</function> or
2321 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2322 <function>ZOOM_resultset_facets</function>.
2323 <function>ZOOM_facet_field_name</function>.
2324 <function>ZOOM_facet_field_get_term</function>.
2326 <para id="zoom.resultset.get_facet_field">
2327 A single Facet field is returned by function
2328 <function>ZOOM_resultset_get_facet_field</function> or
2329 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2330 a result set and facet name or positive index respectively. First
2331 facet has position zero. If no facet could be obtained (invalid name
2332 or index out of bounds) <literal>NULL</literal> is returned.
2334 <para id="zoom.resultset.facets">
2335 An array of facets field can be returned by
2336 <function>ZOOM_resultset_facets</function>. The length of the array is
2337 given by <function>ZOOM_resultset_facets_size</function>. The array is
2338 zero-based and last entry will be at
2339 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2341 <para id="zoom.resultset.facets_names">
2342 It is possible to interate over facets by name, by calling
2343 <function>ZOOM_resultset_facets_names</function>.
2344 This will return an const array of char * where each string can be used
2345 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2348 Function <function>ZOOM_facet_field_name</function> gets the request
2349 facet name from a returned facet field.
2352 Function <function>ZOOM_facet_field_get_term</function> returns the
2353 idx'th term and term count for a facet field.
2354 Idx must between 0 and
2355 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2356 returned reference will be <literal>NULL</literal>. On a valid idx, the
2357 value of the freq reference will be the term count.
2358 The <literal>freq</literal> parameter must be valid pointer to integer.
2361 <sect1 id="zoom.scan"><title>Scan</title>
2363 This section describes an interface for Scan. Scan is not an
2364 official part of the ZOOM model yet. The result of a scan operation
2365 is the <literal>ZOOM_scanset</literal> which is a set of terms
2366 returned by a target.
2370 The Scan interface is supported for both Z39.50, SRU and Solr.
2374 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2375 const char *startpqf);
2377 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2380 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2382 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2383 size_t *occ, size_t *len);
2385 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2386 size_t *occ, size_t *len);
2388 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2390 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2393 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2397 The scan set is created by function
2398 <function>ZOOM_connection_scan</function> which performs a scan
2399 operation on the connection using the specified
2400 <parameter>startpqf</parameter>.
2401 If the operation was successful, the size of the scan set can be
2402 retrieved by a call to <function>ZOOM_scanset_size</function>.
2403 Like result sets, the items are numbered 0,..size-1.
2404 To obtain information about a particular scan term, call function
2405 <function>ZOOM_scanset_term</function>. This function takes
2406 a scan set offset <literal>pos</literal> and returns a pointer
2407 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2409 If present, the <literal>occ</literal> and <literal>len</literal>
2410 are set to the number of occurrences and the length
2411 of the actual term respectively.
2412 <function>ZOOM_scanset_display_term</function> is similar to
2413 <function>ZOOM_scanset_term</function> except that it returns
2414 the <emphasis>display term</emphasis> rather than the raw term.
2415 In a few cases, the term is different from display term. Always
2416 use the display term for display and the raw term for subsequent
2417 scan operations (to get more terms, next scan result, etc).
2420 A scan set may be freed by a call to function
2421 <function>ZOOM_scanset_destroy</function>.
2422 Functions <function>ZOOM_scanset_option_get</function> and
2423 <function>ZOOM_scanset_option_set</function> retrieves and sets
2424 an option respectively.
2427 The <parameter>startpqf</parameter> is a subset of PQF, namely
2428 the Attributes+Term part. Multiple <literal>@attr</literal> can
2429 be used. For example to scan in title (complete) phrases:
2431 @attr 1=4 @attr 6=2 "science o"
2435 The <function>ZOOM_connecton_scan1</function> is a newer and
2436 more generic alternative to <function>ZOOM_connection_scan</function>
2437 which allows to use both CQL and PQF for Scan.
2439 <table frame="top" id="zoom.scanset.options">
2440 <title>ZOOM Scan Set Options</title>
2442 <colspec colwidth="4*" colname="name"></colspec>
2443 <colspec colwidth="7*" colname="description"></colspec>
2444 <colspec colwidth="2*" colname="default"></colspec>
2447 <entry>Option</entry>
2448 <entry>Description</entry>
2449 <entry>Default</entry>
2454 number</entry><entry>Number of Scan Terms requested in next scan.
2455 After scan it holds the actual number of terms returned.
2456 </entry><entry>20</entry></row>
2458 position</entry><entry>Preferred Position of term in response
2459 in next scan; actual position after completion of scan.
2460 </entry><entry>1</entry></row>
2462 stepSize</entry><entry>Step Size
2463 </entry><entry>0</entry></row>
2465 scanStatus</entry><entry>An integer indicating the Scan Status
2467 </entry><entry>0</entry></row>
2469 rpnCharset</entry><entry>Character set for RPN terms.
2470 If this is set, ZOOM C will assume that the ZOOM application is
2471 running UTF-8. Terms in RPN queries are then converted to the
2472 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2473 of RPN terms and no conversion is performed.
2474 </entry><entry>none</entry></row>
2479 <sect1 id="zoom.extendedservices">
2480 <title>Extended Services</title>
2482 ZOOM offers an interface to a subset of the Z39.50 extended services
2483 as well as a few privately defined ones:
2488 Z39.50 Item Order (ILL).
2489 See <xref linkend="zoom.item.order"/>.
2494 Record Update. This allows a client to insert, modify or delete
2496 See <xref linkend="zoom.record.update"/>.
2501 Database Create. This a non-standard feature. Allows a client
2502 to create a database.
2503 See <xref linkend="zoom.database.create"/>.
2508 Database Drop. This a non-standard feature. Allows a client
2509 to delete/drop a database.
2510 See <xref linkend="zoom.database.drop"/>.
2515 Commit operation. This a non-standard feature. Allows a client
2516 to commit operations.
2517 See <xref linkend="zoom.commit"/>.
2520 <!-- all the ILL PDU options should go here too -->
2523 To create an extended service operation a <literal>ZOOM_package</literal>
2524 must be created. The operation is a five step operation. The
2525 package is created, package is configured by means of options,
2526 the package is send, result is inspected (by means of options),
2527 the package is destroyed.
2530 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2531 ZOOM_options options);
2533 const char *ZOOM_package_option_get(ZOOM_package p,
2535 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2537 void ZOOM_package_send(ZOOM_package p, const char *type);
2539 void ZOOM_package_destroy(ZOOM_package p);
2542 The <function>ZOOM_connection_package</function> creates a
2543 package for the connection given using the options specified.
2546 Functions <function>ZOOM_package_option_get</function> and
2547 <function>ZOOM_package_option_set</function> gets and sets
2551 <function>ZOOM_package_send</function> sends
2552 the package the via connection specified in
2553 <function>ZOOM_connection_package</function>.
2554 The <parameter>type</parameter> specifies the actual extended service
2555 package type to be sent.
2557 <table frame="top" id="zoom.extendedservices.options">
2558 <title>Extended Service Common Options</title>
2560 <colspec colwidth="4*" colname="name"></colspec>
2561 <colspec colwidth="7*" colname="description"></colspec>
2562 <colspec colwidth="3*" colname="default"></colspec>
2565 <entry>Option</entry>
2566 <entry>Description</entry>
2567 <entry>Default</entry>
2572 <entry>package-name</entry>
2573 <entry>Extended Service Request package name. Must be specified
2574 as part of a request</entry>
2578 <entry>user-id</entry>
2579 <entry>User ID of Extended Service Package. Is a request option</entry>
2583 <entry>function</entry>
2585 Function of package - one of <literal>create</literal>,
2586 <literal>delete</literal>, <literal>modify</literal>. Is
2589 <entry><literal>create</literal></entry>
2592 <entry>waitAction</entry>
2594 Wait action for package. Possible values:
2595 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2596 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2598 <entry><literal>waitIfPossible</literal></entry>
2601 <entry>targetReference</entry>
2603 Target Reference. This is part of the response as returned
2604 by the server. Read it after a successful operation.
2606 <entry><literal>none</literal></entry>
2611 <sect2 id="zoom.item.order">
2612 <title>Item Order</title>
2614 For Item Order, type must be set to <literal>itemorder</literal> in
2615 <function>ZOOM_package_send</function>.
2618 <table frame="top" id="zoom.item.order.options">
2619 <title>Item Order Options</title>
2621 <colspec colwidth="4*" colname="name"></colspec>
2622 <colspec colwidth="7*" colname="description"></colspec>
2623 <colspec colwidth="3*" colname="default"></colspec>
2626 <entry>Option</entry>
2627 <entry>Description</entry>
2628 <entry>Default</entry>
2633 <entry>contact-name</entry>
2634 <entry>ILL contact name</entry>
2638 <entry>contact-phone</entry>
2639 <entry>ILL contact phone</entry>
2643 <entry>contact-email</entry>
2644 <entry>ILL contact email</entry>
2648 <entry>itemorder-item</entry>
2649 <entry>Position for item (record) requested. An integer</entry>
2656 <sect2 id="zoom.record.update">
2657 <title>Record Update</title>
2659 For Record Update, type must be set to <literal>update</literal> in
2660 <function>ZOOM_package_send</function>.
2662 <table frame="top" id="zoom.record.update.options">
2663 <title>Record Update Options</title>
2665 <colspec colwidth="4*" colname="name"></colspec>
2666 <colspec colwidth="7*" colname="description"></colspec>
2667 <colspec colwidth="3*" colname="default"></colspec>
2670 <entry>Option</entry>
2671 <entry>Description</entry>
2672 <entry>Default</entry>
2677 <entry>action</entry>
2679 The update action. One of
2680 <literal>specialUpdate</literal>,
2681 <literal>recordInsert</literal>,
2682 <literal>recordReplace</literal>,
2683 <literal>recordDelete</literal>,
2684 <literal>elementUpdate</literal>.
2686 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2689 <entry>recordIdOpaque</entry>
2690 <entry>Opaque Record ID</entry>
2694 <entry>recordIdNumber</entry>
2695 <entry>Record ID number</entry>
2699 <entry>record</entry>
2700 <entry>The record itself</entry>
2704 <entry>recordOpaque</entry>
2705 <entry>Specifies an opaque record which is
2706 encoded as an ASN.1 ANY type with the OID as tiven by option
2707 <literal>syntax</literal> (see below).
2708 Option <literal>recordOpaque</literal> is an alternative
2709 to record - and <literal>record</literal> option (above) is
2710 ignored if recordOpaque is set. This option is only available in
2711 YAZ 3.0.35 and later and is meant to facilitate Updates with
2717 <entry>syntax</entry>
2718 <entry>The record syntax (transfer syntax). Is a string that
2719 is a known record syntax.
2721 <entry>no syntax</entry>
2724 <entry>databaseName</entry>
2725 <entry>Database from connection object</entry>
2726 <entry>Default</entry>
2729 <entry>correlationInfo.note</entry>
2730 <entry>Correlation Info Note (string)</entry>
2734 <entry>correlationInfo.id</entry>
2735 <entry>Correlation Info ID (integer)</entry>
2739 <entry>elementSetName</entry>
2740 <entry>Element Set for Record</entry>
2744 <entry>updateVersion</entry>
2745 <entry>Record Update version which holds one of the values
2746 1, 2 or 3. Each version has a distinct OID:
2748 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2750 (second version) and
2751 1.2.840.10003.9.5.1.1
2752 (<ulink url="&url.z39.50.extupdate3;">third and
2753 newest version</ulink>).
2763 <sect2 id="zoom.database.create"><title>Database Create</title>
2765 For Database Create, type must be set to <literal>create</literal> in
2766 <function>ZOOM_package_send</function>.
2769 <table frame="top" id="zoom.database.create.options">
2770 <title>Database Create Options</title>
2772 <colspec colwidth="4*" colname="name"></colspec>
2773 <colspec colwidth="7*" colname="description"></colspec>
2774 <colspec colwidth="3*" colname="default"></colspec>
2777 <entry>Option</entry>
2778 <entry>Description</entry>
2779 <entry>Default</entry>
2784 <entry>databaseName</entry>
2785 <entry>Database from connection object</entry>
2786 <entry>Default</entry>
2792 <sect2 id="zoom.database.drop">
2793 <title>Database Drop</title>
2795 For Database Drop, type must be set to <literal>drop</literal> in
2796 <function>ZOOM_package_send</function>.
2798 <table frame="top" id="zoom.database.drop.options">
2799 <title>Database Drop Options</title>
2801 <colspec colwidth="4*" colname="name"></colspec>
2802 <colspec colwidth="7*" colname="description"></colspec>
2803 <colspec colwidth="3*" colname="default"></colspec>
2806 <entry>Option</entry>
2807 <entry>Description</entry>
2808 <entry>Default</entry>
2813 <entry>databaseName</entry>
2814 <entry>Database from connection object</entry>
2815 <entry>Default</entry>
2821 <sect2 id="zoom.commit">
2822 <title>Commit Operation</title>
2824 For Commit, type must be set to <literal>commit</literal> in
2825 <function>ZOOM_package_send</function>.
2828 <sect2 id="zoom.extended.services.behavior">
2829 <title>Protocol behavior</title>
2831 All the extended services are Z39.50-only.
2835 The database create, drop and commit services are privately defined
2837 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2843 <sect1 id="zoom.options">
2844 <title>Options</title>
2846 Most &zoom; objects provide a way to specify options to change behavior.
2847 From an implementation point of view a set of options is just like
2848 an associative array / hash.
2851 ZOOM_options ZOOM_options_create(void);
2853 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
2855 void ZOOM_options_destroy(ZOOM_options opt);
2858 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
2860 void ZOOM_options_set(ZOOM_options opt, const char *name,
2864 typedef const char *(*ZOOM_options_callback)
2865 (void *handle, const char *name);
2867 ZOOM_options_callback
2868 ZOOM_options_set_callback(ZOOM_options opt,
2869 ZOOM_options_callback c,
2873 <sect1 id="zoom.queryconversions">
2874 <title>Query conversions</title>
2876 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
2877 ZOOM_connection conn);
2879 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
2881 int *ccl_error, const char **error_string,
2885 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
2886 client-side, into RPN which may be passed to the server.
2887 This is useful for server's that don't themselves
2888 support CQL, for which <function>ZOOM_query_cql</function> is useless.
2889 `conn' is used only as a place to stash diagnostics if compilation
2890 fails; if this information is not needed, a null pointer may be used.
2891 The CQL conversion is driven by option <literal>cqlfile</literal> from
2892 connection conn. This specifies a conversion file (eg pqf.properties)
2893 which <emphasis>must</emphasis> be present.
2896 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
2897 client-side, into RPN which may be passed to the server.
2898 The conversion is driven by the specification given by
2899 <literal>config</literal>. Upon completion 0 is returned on success; -1
2900 is returned on on failure. Om failure <literal>error_string</literal> and
2901 <literal>error_pos</literal> holds error message and position of
2902 first error in original CCL string.
2905 <sect1 id="zoom.events"><title>Events</title>
2907 If you're developing non-blocking applications, you have to deal
2911 int ZOOM_event(int no, ZOOM_connection *cs);
2914 The <function>ZOOM_event</function> executes pending events for
2915 a number of connections. Supply the number of connections in
2916 <literal>no</literal> and an array of connections in
2917 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
2918 A pending event could be a sending a search, receiving a response,
2920 When an event has occurred for one of the connections, this function
2921 returns a positive integer <literal>n</literal> denoting that an event
2922 occurred for connection <literal>cs[n-1]</literal>.
2923 When no events are pending for the connections, a value of zero is
2925 To ensure that all outstanding requests are performed call this function
2926 repeatedly until zero is returned.
2929 If <function>ZOOM_event</function> returns and returns non-zero, the
2930 last event that occurred can be expected.
2933 int ZOOM_connection_last_event(ZOOM_connection cs);
2936 <function>ZOOM_connection_last_event</function> returns an event type
2937 (integer) for the last event.
2940 <table frame="top" id="zoom.event.ids">
2941 <title>ZOOM Event IDs</title>
2943 <colspec colwidth="4*" colname="name"></colspec>
2944 <colspec colwidth="7*" colname="description"></colspec>
2947 <entry>Event</entry>
2948 <entry>Description</entry>
2953 <entry>ZOOM_EVENT_NONE</entry>
2954 <entry>No event has occurred</entry>
2957 <entry>ZOOM_EVENT_CONNECT</entry>
2958 <entry>TCP/IP connect has initiated</entry>
2961 <entry>ZOOM_EVENT_SEND_DATA</entry>
2962 <entry>Data has been transmitted (sending)</entry>
2965 <entry>ZOOM_EVENT_RECV_DATA</entry>
2966 <entry>Data has been received)</entry>
2969 <entry>ZOOM_EVENT_TIMEOUT</entry>
2970 <entry>Timeout</entry>
2973 <entry>ZOOM_EVENT_UNKNOWN</entry>
2974 <entry>Unknown event</entry>
2977 <entry>ZOOM_EVENT_SEND_APDU</entry>
2978 <entry>An APDU has been transmitted (sending)</entry>
2981 <entry>ZOOM_EVENT_RECV_APDU</entry>
2982 <entry>An APDU has been received</entry>
2985 <entry>ZOOM_EVENT_RECV_RECORD</entry>
2986 <entry>A result-set record has been received</entry>
2989 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
2990 <entry>A search result been received</entry>
2997 <chapter id="server">
2998 <title>Generic server</title>
2999 <sect1 id="server.introduction"><title>Introduction</title>
3001 If you aren't into documentation, a good way to learn how the
3002 back end interface works is to look at the <filename>backend.h</filename>
3003 file. Then, look at the small dummy-server in
3004 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
3005 file also makes a good reference, once you've chewed your way through
3006 the prose of this file.
3009 If you have a database system that you would like to make available by
3010 means of Z39.50 or SRU, &yaz; basically offers your two options. You
3011 can use the APIs provided by the &asn;, &odr;, and &comstack;
3013 create and decode PDUs, and exchange them with a client.
3014 Using this low-level interface gives you access to all fields and
3015 options of the protocol, and you can construct your server as close
3016 to your existing database as you like.
3017 It is also a fairly involved process, requiring
3018 you to set up an event-handling mechanism, protocol state machine,
3019 etc. To simplify server implementation, we have implemented a compact
3020 and simple, but reasonably full-functioned server-frontend that will
3021 handle most of the protocol mechanics, while leaving you to
3022 concentrate on your database interface.
3026 The backend interface was designed in anticipation of a specific
3027 integration task, while still attempting to achieve some degree of
3028 generality. We realize fully that there are points where the
3029 interface can be improved significantly. If you have specific
3030 functions or parameters that you think could be useful, send us a
3031 mail (or better, sign on to the mailing list referred to in the
3032 top-level README file). We will try to fit good suggestions into future
3033 releases, to the extent that it can be done without requiring
3034 too many structural changes in existing applications.
3039 The &yaz; server does not support XCQL.
3043 <sect1 id="server.frontend">
3044 <title>The Database Frontend</title>
3046 We refer to this software as a generic database frontend. Your
3047 database system is the <emphasis>backend database</emphasis>, and the
3048 interface between the two is called the <emphasis>backend API</emphasis>.
3049 The backend API consists of a small number of function handlers and
3050 structure definitions. You are required to provide the
3051 <function>main()</function> routine for the server (which can be
3052 quite simple), as well as a set of handlers to match each of the
3054 The interface functions that you write can use any mechanism you like
3055 to communicate with your database system: You might link the whole
3056 thing together with your database application and access it by
3057 function calls; you might use IPC to talk to a database server
3058 somewhere; or you might link with third-party software that handles
3059 the communication for you (like a commercial database client library).
3060 At any rate, the handlers will perform the tasks of:
3073 Scanning the database index (optional - if you wish to implement SCAN).
3076 Extended Services (optional).
3079 Result-Set Delete (optional).
3082 Result-Set Sort (optional).
3085 Return Explain for SRU (optional).
3089 (more functions will be added in time to support as much of
3090 Z39.50-1995 as possible).
3093 <sect1 id="server.backend">
3094 <title>The Backend API</title>
3096 The header file that you need to use the interface are in the
3097 <filename>include/yaz</filename> directory. It's called
3098 <filename>backend.h</filename>. It will include other files from
3099 the <filename>include/yaz</filename> directory, so you'll
3100 probably want to use the -I option of your compiler to tell it
3101 where to find the files. When you run
3102 <literal>make</literal> in the top-level &yaz; directory,
3103 everything you need to create your server is to link with the
3104 <filename>lib/libyaz.la</filename> library.
3107 <sect1 id="server.main">
3108 <title>Your main() Routine</title>
3110 As mentioned, your <function>main()</function> routine can be quite brief.
3111 If you want to initialize global parameters, or read global configuration
3112 tables, this is the place to do it. At the end of the routine, you should
3116 int statserv_main(int argc, char **argv,
3117 bend_initresult *(*bend_init)(bend_initrequest *r),
3118 void (*bend_close)(void *handle));
3121 The third and fourth arguments are pointers to handlers. Handler
3122 <function>bend_init</function> is called whenever the server receives
3123 an Initialize Request, so it serves as a Z39.50 session initializer. The
3124 <function>bend_close</function> handler is called when the session is
3128 <function>statserv_main</function> will establish listening sockets
3129 according to the parameters given. When connection requests are received,
3130 the event handler will typically <function>fork()</function> and
3131 create a sub-process to handle a new connection.
3132 Alternatively the server may be setup to create threads for each
3134 If you do use global variables and forking, you should be aware, then,
3135 that these cannot be shared between associations, unless you explicitly
3136 disable forking by command line parameters.
3139 The server provides a mechanism for controlling some of its behavior
3140 without using command-line options. The function
3143 statserv_options_block *statserv_getcontrol(void);
3146 will return a pointer to a <literal>struct statserv_options_block</literal>
3147 describing the current default settings of the server. The structure
3148 contains these elements:
3151 <term><literal>int dynamic</literal></term>
3153 A boolean value, which determines whether the server
3154 will fork on each incoming request (TRUE), or not (FALSE). Default is
3155 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3160 <term><literal>int threads</literal></term>
3162 A boolean value, which determines whether the server
3163 will create a thread on each incoming request (TRUE), or not (FALSE).
3164 Default is FALSE. This flag is only read by UNIX-based servers
3165 that offer POSIX Threads support.
3166 WIN32-based servers always operate in threaded mode.
3170 <term><literal>int inetd</literal></term>
3172 A boolean value, which determines whether the server
3173 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3177 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3178 <listitem><para>File for diagnostic output ("": stderr).
3182 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3184 Name of file for logging incoming and outgoing APDUs
3185 ("": don't log APDUs, "-":
3186 <literal>stderr</literal>).
3190 <term><literal>char default_listen[1024]</literal></term>
3191 <listitem><para>Same form as the command-line specification of
3192 listener address. "": no default listener address.
3193 Default is to listen at "tcp:@:9999". You can only
3194 specify one default listener address in this fashion.
3198 <term><literal>enum oid_proto default_proto;</literal></term>
3199 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3200 <literal>PROTO_SR</literal>.
3201 Default is <literal>PROTO_Z39_50</literal>.
3205 <term><literal>int idle_timeout;</literal></term>
3206 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3207 no (infinite) timeout. Default is 15 minutes.
3211 <term><literal>int maxrecordsize;</literal></term>
3212 <listitem><para>Maximum permissible record (message) size. Default
3213 is 64 MB. This amount of memory will only be allocated if a
3214 client requests a very large amount of records in one operation
3216 Set it to a lower number if you are worried about resource
3217 consumption on your host system.
3221 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3222 <listitem><para>Passed to the backend when a new connection is received.
3226 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3227 <listitem><para>Set user id to the user specified, after binding
3228 the listener addresses.
3233 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3235 <listitem><para>Pointer to function which is called after the
3236 command line options have been parsed - but before the server
3238 For forked UNIX servers this handler is called in the mother
3239 process; for threaded servers this handler is called in the
3241 The default value of this pointer is NULL in which case it
3242 isn't invoked by the frontend server.
3243 When the server operates as an NT service this handler is called
3244 whenever the service is started.
3249 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3251 <listitem><para>Pointer to function which is called whenever the server
3252 has stopped listening for incoming connections. This function pointer
3253 has a default value of NULL in which case it isn't called.
3254 When the server operates as an NT service this handler is called
3255 whenever the service is stopped.
3259 <term><literal>void *handle</literal></term>
3260 <listitem><para>User defined pointer (default value NULL).
3261 This is a per-server handle that can be used to specify "user-data".
3262 Do not confuse this with the session-handle as returned by bend_init.
3268 The pointer returned by <literal>statserv_getcontrol</literal> points to
3269 a static area. You are allowed to change the contents of the structure,
3270 but the changes will not take effect before you call
3273 void statserv_setcontrol(statserv_options_block *block);
3277 that you should generally update this structure before calling
3278 <function>statserv_main()</function>.
3282 <sect1 id="server.backendfunctions">
3283 <title>The Backend Functions</title>
3285 For each service of the protocol, the backend interface declares one or
3286 two functions. You are required to provide implementations of the
3287 functions representing the services that you wish to implement.
3289 <sect2 id="server.init">
3292 bend_initresult (*bend_init)(bend_initrequest *r);
3295 This handler is called once for each new connection request, after
3296 a new process/thread has been created, and an Initialize Request has
3297 been received from the client. The pointer to the
3298 <function>bend_init</function> handler is passed in the call to
3299 <function>statserv_start</function>.
3302 This handler is also called when operating in SRU mode - when
3303 a connection has been made (even though SRU does not offer
3307 Unlike previous versions of YAZ, the <function>bend_init</function> also
3308 serves as a handler that defines the Z39.50 services that the backend
3309 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3310 including search - and fetch must be specified here in this handler.
3313 The request - and result structures are defined as
3316 typedef struct bend_initrequest
3318 /** \brief user/name/password to be read */
3319 Z_IdAuthentication *auth;
3320 /** \brief encoding stream (for results) */
3322 /** \brief printing stream */
3324 /** \brief decoding stream (use stream for results) */
3326 /** \brief reference ID */
3327 Z_ReferenceId *referenceId;
3328 /** \brief peer address of client */
3331 /** \brief character set and language negotiation
3333 see include/yaz/z-charneg.h
3335 Z_CharSetandLanguageNegotiation *charneg_request;
3337 /** \brief character negotiation response */
3338 Z_External *charneg_response;
3340 /** \brief character set (encoding) for query terms
3342 This is NULL by default. It should be set to the native character
3343 set that the backend assumes for query terms */
3344 char *query_charset;
3346 /** \brief whehter query_charset also applies to recors
3348 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3349 character set as queries. If in doubt, use 0 (No).
3351 int records_in_same_charset;
3353 char *implementation_id;
3354 char *implementation_name;
3355 char *implementation_version;
3357 /** \brief Z39.50 sort handler */
3358 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3359 /** \brief SRU/Z39.50 search handler */
3360 int (*bend_search)(void *handle, bend_search_rr *rr);
3361 /** \brief SRU/Z39.50 fetch handler */
3362 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3363 /** \brief SRU/Z39.50 present handler */
3364 int (*bend_present)(void *handle, bend_present_rr *rr);
3365 /** \brief Z39.50 extended services handler */
3366 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3367 /** \brief Z39.50 delete result set handler */
3368 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3369 /** \brief Z39.50 scan handler */
3370 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3371 /** \brief Z39.50 segment facility handler */
3372 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3373 /** \brief SRU explain handler */
3374 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3375 /** \brief SRU scan handler */
3376 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3377 /** \brief SRU record update handler */
3378 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3380 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3381 int named_result_sets;
3384 typedef struct bend_initresult
3386 int errcode; /* 0==OK */
3387 char *errstring; /* system error string or NULL */
3388 void *handle; /* private handle to the backend module */
3392 In general, the server frontend expects that the
3393 <literal>bend_*result</literal> pointer that you return is valid at
3394 least until the next call to a <literal>bend_* function</literal>.
3395 This applies to all of the functions described herein. The parameter
3396 structure passed to you in the call belongs to the server frontend, and
3397 you should not make assumptions about its contents after the current
3398 function call has completed. In other words, if you want to retain any
3399 of the contents of a request structure, you should copy them.
3402 The <literal>errcode</literal> should be zero if the initialization of
3403 the backend went well. Any other value will be interpreted as an error.
3404 The <literal>errstring</literal> isn't used in the current version, but
3405 one option would be to stick it in the initResponse as a VisibleString.
3406 The <literal>handle</literal> is the most important parameter. It should
3407 be set to some value that uniquely identifies the current session to
3408 the backend implementation. It is used by the frontend server in any
3409 future calls to a backend function.
3410 The typical use is to set it to point to a dynamically allocated state
3411 structure that is private to your backend module.
3414 The <literal>auth</literal> member holds the authentication information
3415 part of the Z39.50 Initialize Request. Interpret this if your serves
3416 requires authentication.
3419 The members <literal>peer_name</literal>,
3420 <literal>implementation_id</literal>,
3421 <literal>implementation_name</literal> and
3422 <literal>implementation_version</literal> holds
3423 DNS of client, ID of implementor, name
3424 of client (Z39.50) implementation - and version.
3427 The <literal>bend_</literal> - members are set to NULL when
3428 <function>bend_init</function> is called. Modify the pointers by
3429 setting them to point to backend functions.
3432 <sect2 id="server.search.retrieve">
3433 <title>Search and Retrieve</title>
3435 We now describe the handlers that are required to support search -
3436 and retrieve. You must support two functions - one for search - and one
3437 for fetch (retrieval of one record). If desirable you can provide a
3438 third handler which is called when a present request is received which
3439 allows you to optimize retrieval of multiple-records.
3442 int (*bend_search) (void *handle, bend_search_rr *rr);
3445 char *setname; /* name to give to this set */
3446 int replace_set; /* replace set, if it already exists */
3447 int num_bases; /* number of databases in list */
3448 char **basenames; /* databases to search */
3449 Z_ReferenceId *referenceId;/* reference ID */
3450 Z_Query *query; /* query structure */
3451 ODR stream; /* encode stream */
3452 ODR decode; /* decode stream */
3453 ODR print; /* print stream */
3455 bend_request request;
3456 bend_association association;
3458 int hits; /* number of hits */
3459 int errcode; /* 0==OK */
3460 char *errstring; /* system error string or NULL */
3461 Z_OtherInformation *search_info; /* additional search info */
3462 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3463 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3464 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3465 int estimated_hit_count; /* if hit count is estimated */
3466 int partial_resultset; /* if result set is partial */
3470 The <function>bend_search</function> handler is a fairly close
3471 approximation of a protocol Z39.50 Search Request - and Response PDUs
3472 The <literal>setname</literal> is the resultSetName from the protocol.
3473 You are required to establish a mapping between the set name and whatever
3474 your backend database likes to use.
3475 Similarly, the <literal>replace_set</literal> is a boolean value
3476 corresponding to the resultSetIndicator field in the protocol.
3477 <literal>num_bases/basenames</literal> is a length of/array of character
3478 pointers to the database names provided by the client.
3479 The <literal>query</literal> is the full query structure as defined in
3480 the protocol ASN.1 specification.
3481 It can be either of the possible query types, and it's up to you to
3482 determine if you can handle the provided query type.
3483 Rather than reproduce the C interface here, we'll refer you to the
3484 structure definitions in the file
3485 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3486 attributeSetId OID of the RPN query, you can either match it against
3487 your own internal tables, or you can use the <link linkend="tools.oid">
3491 The structure contains a number of hits, and an
3492 <literal>errcode/errstring</literal> pair. If an error occurs
3493 during the search, or if you're unhappy with the request, you should
3494 set the errcode to a value from the BIB-1 diagnostic set. The value
3495 will then be returned to the user in a nonsurrogate diagnostic record
3496 in the response. The <literal>errstring</literal>, if provided, will
3497 go in the addinfo field. Look at the protocol definition for the
3498 defined error codes, and the suggested uses of the addinfo field.
3501 The <function>bend_search</function> handler is also called when
3502 the frontend server receives a SRU SearchRetrieveRequest.
3503 For SRU, a CQL query is usually provided by the client.
3504 The CQL query is available as part of <literal>Z_Query</literal>
3505 structure (note that CQL is now part of Z39.50 via an external).
3506 To support CQL in existing implementations that only do Type-1,
3507 we refer to the CQL-to-PQF tool described
3508 <link linkend="cql.to.pqf">here</link>.
3511 To maintain backwards compatibility, the frontend server
3512 of yaz always assume that error codes are BIB-1 diagnostics.
3513 For SRU operation, a Bib-1 diagnostic code is mapped to
3517 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3519 typedef struct bend_fetch_rr {
3520 char *setname; /* set name */
3521 int number; /* record number */
3522 Z_ReferenceId *referenceId;/* reference ID */
3523 Odr_oid *request_format; /* format, transfer syntax (OID) */
3524 Z_RecordComposition *comp; /* Formatting instructions */
3525 ODR stream; /* encoding stream - memory source if req */
3526 ODR print; /* printing stream */
3528 char *basename; /* name of database that provided record */
3529 int len; /* length of record or -1 if structured */
3530 char *record; /* record */
3531 int last_in_set; /* is it? */
3532 Odr_oid *output_format; /* response format/syntax (OID) */
3533 int errcode; /* 0==success */
3534 char *errstring; /* system error string or NULL */
3535 int surrogate_flag; /* surrogate diagnostic */
3536 char *schema; /* string record schema input/output */
3540 The frontend server calls the <function>bend_fetch</function> handler
3541 when it needs database records to fulfill a Z39.50 Search Request, a
3542 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3543 The <literal>setname</literal> is simply the name of the result set
3544 that holds the reference to the desired record.
3545 The <literal>number</literal> is the offset into the set (with 1
3546 being the first record in the set). The <literal>format</literal> field
3547 is the record format requested by the client (See
3548 <xref linkend="tools.oid"/>).
3549 A value of NULL for <literal>format</literal> indicates that the
3550 client did not request a specific format.
3551 The <literal>stream</literal> argument is an &odr; stream which
3552 should be used for allocating space for structured data records.
3553 The stream will be reset when all records have been assembled, and
3554 the response package has been transmitted.
3555 For unstructured data, the backend is responsible for maintaining a
3556 static or dynamic buffer for the record between calls.
3559 If a SRU SearchRetrieveRequest is received by the frontend server,
3560 the <literal>referenceId</literal> is NULL and the
3561 <literal>format</literal> (transfer syntax) is the OID for XML.
3562 The schema for SRU is stored in both the
3563 <literal>Z_RecordComposition</literal>
3564 structure and <literal>schema</literal> (simple string).
3567 In the structure, the <literal>basename</literal> is the name of the
3568 database that holds the
3569 record. <literal>len</literal> is the length of the record returned, in
3570 bytes, and <literal>record</literal> is a pointer to the record.
3571 <literal>last_in_set</literal> should be nonzero only if the record
3572 returned is the last one in the given result set.
3573 <literal>errcode</literal> and <literal>errstring</literal>, if
3574 given, will be interpreted as a global error pertaining to the
3575 set, and will be returned in a non-surrogate-diagnostic.
3576 If you wish to return the error as a surrogate-diagnostic
3577 (local error) you can do this by setting
3578 <literal>surrogate_flag</literal> to 1 also.
3581 If the <literal>len</literal> field has the value -1, then
3582 <literal>record</literal> is assumed to point to a constructed data
3583 type. The <literal>format</literal> field will be used to determine
3584 which encoder should be used to serialize the data.
3588 If your backend generates structured records, it should use
3589 <function>odr_malloc()</function> on the provided stream for allocating
3590 data: This allows the frontend server to keep track of the record sizes.
3594 The <literal>format</literal> field is mapped to an object identifier
3595 in the direct reference of the resulting EXTERNAL representation
3600 The current version of &yaz; only supports the direct reference mode.
3604 int (*bend_present) (void *handle, bend_present_rr *rr);
3607 char *setname; /* set name */
3609 int number; /* record number */
3610 Odr_oid *format; /* format, transfer syntax (OID) */
3611 Z_ReferenceId *referenceId;/* reference ID */
3612 Z_RecordComposition *comp; /* Formatting instructions */
3613 ODR stream; /* encoding stream - memory source if required */
3614 ODR print; /* printing stream */
3615 bend_request request;
3616 bend_association association;
3618 int hits; /* number of hits */
3619 int errcode; /* 0==OK */
3620 char *errstring; /* system error string or NULL */
3624 The <function>bend_present</function> handler is called when
3625 the server receives a Z39.50 Present Request.
3626 The <literal>setname</literal>,
3627 <literal>start</literal> and <literal>number</literal> is the
3628 name of the result set - start position - and number of records to
3629 be retrieved respectively. <literal>format</literal> and
3630 <literal>comp</literal> is the preferred transfer syntax and element
3631 specifications of the present request.
3634 Note that this is handler serves as a supplement for
3635 <function>bend_fetch</function> and need not to be defined in order to
3636 support search - and retrieve.
3639 <sect2 id="server.delete">
3640 <title>Delete</title>
3642 For back-ends that supports delete of a result set only one handler
3646 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3648 typedef struct bend_delete_rr {
3652 Z_ReferenceId *referenceId;
3653 int delete_status; /* status for the whole operation */
3654 int *statuses; /* status each set - indexed as setnames */
3661 The delete set function definition is rather primitive, mostly because
3662 we have had no practical need for it as of yet. If someone wants
3663 to provide a full delete service, we'd be happy to add the
3664 extra parameters that are required. Are there clients out there
3665 that will actually delete sets they no longer need?
3669 <sect2 id="server.scan">
3672 For servers that wish to offer the scan service one handler
3676 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3679 BEND_SCAN_SUCCESS, /* ok */
3680 BEND_SCAN_PARTIAL /* not all entries could be found */
3683 typedef struct bend_scan_rr {
3684 int num_bases; /* number of elements in databaselist */
3685 char **basenames; /* databases to search */
3686 Odr_oid *attributeset;
3687 Z_ReferenceId *referenceId; /* reference ID */
3688 Z_AttributesPlusTerm *term;
3689 ODR stream; /* encoding stream - memory source if required */
3690 ODR print; /* printing stream */
3692 int *step_size; /* step size */
3693 int term_position; /* desired index of term in result list/returned */
3694 int num_entries; /* number of entries requested/returned */
3696 /* scan term entries. The called handler does not have
3697 to allocate this. Size of entries is num_entries (see above) */
3698 struct scan_entry *entries;
3699 bend_scan_status status;
3702 char *scanClause; /* CQL scan clause */
3703 char *setname; /* Scan in result set (NULL if omitted) */
3707 This backend server handles both Z39.50 scan
3708 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3709 Z39.50 Scan , it must check for a non-NULL value of
3710 <literal>scanClause</literal>.
3714 if designed today, it would be a choice using a union or similar,
3715 but that would break binary compatibility with existing servers.
3720 <sect1 id="server.invocation">
3721 <title>Application Invocation</title>
3723 The finished application has the following
3724 invocation syntax (by way of <function>statserv_main()</function>):
3732 A listener specification consists of a transport mode followed by a
3733 colon (:) followed by a listener address. The transport mode is
3734 either <literal>tcp</literal>, <literal>unix:</literal> or
3735 <literal>ssl</literal>.
3738 For TCP and SSL, an address has the form
3741 hostname | IP-number [: portnumber]
3744 The port number defaults to 210 (standard Z39.50 port).
3747 For UNIX, the address is the filename of socket.
3750 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3751 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3752 IPV4 binding as well (bindv6only=0),
3753 The special hostname <literal>@4</literal> binds to
3754 <literal>INADDR_ANY</literal> (IPV4 only listener).
3755 The special hostname <literal>@6</literal> binds to
3756 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3758 <example id="server.example.running.unix">
3759 <title>Running the GFS on Unix</title>
3761 Assuming the server application <replaceable>appname</replaceable> is
3762 started as root, the following will make it listen on port 210.
3763 The server will change identity to <literal>nobody</literal>
3764 and write its log to <filename>/var/log/app.log</filename>.
3766 application -l /var/log/app.log -u nobody tcp:@:210
3770 The server will accept Z39.50 requests and offer SRU service on port 210.
3773 <example id="server.example.apache.sru">
3774 <title>Setting up Apache as SRU Frontend</title>
3776 If you use <ulink url="&url.apache;">Apache</ulink>
3777 as your public web server and want to offer HTTP port 80
3778 access to the YAZ server on 210, you can use the
3779 <ulink url="&url.apache.directive.proxypass;">
3780 <literal>ProxyPass</literal></ulink>
3782 If you have virtual host
3783 <literal>srw.mydomain</literal> you can use the following directives
3784 in Apache's httpd.conf:
3787 ErrorLog /home/srw/logs/error_log
3788 TransferLog /home/srw/logs/access_log
3789 ProxyPass / http://srw.mydomain:210/
3794 The above for the Apache 1.3 series.
3797 <example id="server.example.local.access">
3798 <title>Running a server with local access only</title>
3800 Servers that is only being accessed from the local host should listen
3801 on UNIX file socket rather than a Internet socket. To listen on
3802 <filename>/tmp/mysocket</filename> start the server as follows:
3804 application unix:/tmp/mysocket
3809 <sect1 id="server.vhosts">
3810 <title>GFS Configuration and Virtual Hosts</title>
3815 <title>The Z39.50 ASN.1 Module</title>
3816 <sect1 id="asn.introduction">
3817 <title>Introduction</title>
3819 The &asn; module provides you with a set of C struct definitions for the
3820 various PDUs of the Z39.50 protocol, as well as for the complex types
3821 appearing within the PDUs. For the primitive data types, the C
3822 representation often takes the form of an ordinary C language type,
3823 such as <literal>Odr_int</literal> which is equivalent to an integral
3824 C integer. For ASN.1 constructs that have no direct
3825 representation in C, such as general octet strings and bit strings,
3826 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3827 provides auxiliary definitions.
3830 The &asn; module is located in sub directory <filename>z39.50</filename>.
3831 There you'll find C files that implements encoders and decoders for the
3832 Z39.50 types. You'll also find the protocol definitions:
3833 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3837 <sect1 id="asn.preparing">
3838 <title>Preparing PDUs</title>
3840 A structure representing a complex ASN.1 type doesn't in itself contain the
3841 members of that type. Instead, the structure contains
3842 <emphasis>pointers</emphasis> to the members of the type.
3843 This is necessary, in part, to allow a mechanism for specifying which
3844 of the optional structure (SEQUENCE) members are present, and which
3845 are not. It follows that you will need to somehow provide space for
3846 the individual members of the structure, and set the pointers to
3847 refer to the members.
3850 The conversion routines don't care how you allocate and maintain your
3851 C structures - they just follow the pointers that you provide.
3852 Depending on the complexity of your application, and your personal
3853 taste, there are at least three different approaches that you may take
3854 when you allocate the structures.
3857 You can use static or automatic local variables in the function that
3858 prepares the PDU. This is a simple approach, and it provides the most
3859 efficient form of memory management. While it works well for flat
3860 PDUs like the InitReqest, it will generally not be sufficient for say,
3861 the generation of an arbitrarily complex RPN query structure.
3864 You can individually create the structure and its members using the
3865 <function>malloc(2)</function> function. If you want to ensure that
3866 the data is freed when it is no longer needed, you will have to
3867 define a function that individually releases each member of a
3868 structure before freeing the structure itself.
3871 You can use the <function>odr_malloc()</function> function (see
3872 <xref linkend="odr.use"/> for details). When you use
3873 <function>odr_malloc()</function>, you can release all of the
3874 allocated data in a single operation, independent of any pointers and
3875 relations between the data. <function>odr_malloc()</function> is based on a
3876 "nibble-memory"
3877 scheme, in which large portions of memory are allocated, and then
3878 gradually handed out with each call to <function>odr_malloc()</function>.
3879 The next time you call <function>odr_reset()</function>, all of the
3880 memory allocated since the last call is recycled for future use (actually,
3881 it is placed on a free-list).
3884 You can combine all of the methods described here. This will often be
3885 the most practical approach. For instance, you might use
3886 <function>odr_malloc()</function> to allocate an entire structure and
3887 some of its elements, while you leave other elements pointing to global
3888 or per-session default variables.
3891 The &asn; module provides an important aid in creating new PDUs. For
3892 each of the PDU types (say, <function>Z_InitRequest</function>), a
3893 function is provided that allocates and initializes an instance of
3894 that PDU type for you. In the case of the InitRequest, the function is
3895 simply named <function>zget_InitRequest()</function>, and it sets up
3896 reasonable default value for all of the mandatory members. The optional
3897 members are generally initialized to null pointers. This last aspect
3898 is very important: it ensures that if the PDU definitions are
3899 extended after you finish your implementation (to accommodate
3900 new versions of the protocol, say), you won't get into trouble with
3901 uninitialized pointers in your structures. The functions use
3902 <function>odr_malloc()</function> to
3903 allocate the PDUs and its members, so you can free everything again with a
3904 single call to <function>odr_reset()</function>. We strongly recommend
3905 that you use the <literal>zget_*</literal>
3906 functions whenever you are preparing a PDU (in a C++ API, the
3907 <literal>zget_</literal>
3908 functions would probably be promoted to constructors for the
3912 The prototype for the individual PDU types generally look like this:
3915 Z_<type> *zget_<type>(ODR o);
3921 Z_InitRequest *zget_InitRequest(ODR o);
3924 The &odr; handle should generally be your encoding stream, but it
3928 As well as the individual PDU functions, a function
3929 <function>zget_APDU()</function> is provided, which allocates
3930 a top-level Z-APDU of the type requested:
3933 Z_APDU *zget_APDU(ODR o, int which);
3936 The <varname>which</varname> parameter is (of course) the discriminator
3937 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
3938 All of the interface described here is provided by the &asn; module, and
3939 you access it through the <filename>proto.h</filename> header file.
3942 <sect1 id="asn.external">
3943 <title>EXTERNAL Data</title>
3945 In order to achieve extensibility and adaptability to different
3946 application domains, the new version of the protocol defines many
3947 structures outside of the main ASN.1 specification, referencing them
3948 through ASN.1 EXTERNAL constructs. To simplify the construction and
3949 access to the externally referenced data, the &asn; module defines a
3950 specialized version of the EXTERNAL construct, called
3951 <literal>Z_External</literal>.It is defined thus:
3954 typedef struct Z_External
3956 Odr_oid *direct_reference;
3957 int *indirect_reference;
3962 Z_External_single = 0,
3964 Z_External_arbitrary,
3966 /* Specific types */
3968 Z_External_explainRecord,
3969 Z_External_resourceReport1,
3970 Z_External_resourceReport2
3978 Odr_any *single_ASN1_type;
3979 Odr_oct *octet_aligned;
3980 Odr_bitmask *arbitrary;
3982 /* Specific types */
3984 Z_ExplainRecord *explainRecord;
3985 Z_ResourceReport1 *resourceReport1;
3986 Z_ResourceReport2 *resourceReport2;
3994 When decoding, the &asn; module will attempt to determine which
3995 syntax describes the data by looking at the reference fields
3996 (currently only the direct-reference). For ASN.1 structured data, you
3997 need only consult the <literal>which</literal> field to determine the
3998 type of data. You can the access the data directly through the union.
3999 When constructing data for encoding, you set the union pointer to point
4000 to the data, and set the <literal>which</literal> field accordingly.
4001 Remember also to set the direct (or indirect) reference to the correct
4002 OID for the data type.
4003 For non-ASN.1 data such as MARC records, use the
4004 <literal>octet_aligned</literal> arm of the union.
4007 Some servers return ASN.1 structured data values (eg. database
4008 records) as BER-encoded records placed in the
4009 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
4010 The ASN-module will <emphasis>not</emphasis> automatically decode
4011 these records. To help you decode the records in the application, the
4015 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
4018 Can be used to retrieve information about the known, external data
4019 types. The function return a pointer to a static area, or NULL, if no
4020 match for the given direct reference is found. The
4021 <literal>Z_ext_typeent</literal>
4025 typedef struct Z_ext_typeent
4027 int oid[OID_SIZE]; /* the direct-reference OID. */
4028 int what; /* discriminator value for the external CHOICE */
4029 Odr_fun fun; /* decoder function */
4033 The <literal>what</literal> member contains the
4034 <literal>Z_External</literal> union discriminator value for the
4035 given type: For the SUTRS record syntax, the value would be
4036 <literal>Z_External_sutrs</literal>.
4037 The <literal>fun</literal> member contains a pointer to the
4038 function which encodes/decodes the given type. Again, for the SUTRS
4039 record syntax, the value of <literal>fun</literal> would be
4040 <literal>z_SUTRS</literal> (a function pointer).
4043 If you receive an EXTERNAL which contains an octet-string value that
4044 you suspect of being an ASN.1-structured data value, you can use
4045 <literal>z_ext_gettypebyref</literal> to look for the provided
4047 If the return value is different from NULL, you can use the provided
4048 function to decode the BER string (see <xref linkend="odr.use"/>
4052 If you want to <emphasis>send</emphasis> EXTERNALs containing
4053 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4054 is possible too. However, on the encoding phase, it requires a somewhat
4055 involved juggling around of the various buffers involved.
4058 If you need to add new, externally defined data types, you must update
4059 the struct above, in the source file <filename>prt-ext.h</filename>, as
4060 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4061 When changing the latter, remember to update both the
4062 <literal>arm</literal> arrary and the list
4063 <literal>type_table</literal>, which drives the CHOICE biasing that
4064 is necessary to tell the different, structured types apart
4069 Eventually, the EXTERNAL processing will most likely
4070 automatically insert the correct OIDs or indirect-refs. First,
4071 however, we need to determine how application-context management
4072 (specifically the presentation-context-list) should fit into the
4077 <sect1 id="asn.pdu">
4078 <title>PDU Contents Table</title>
4080 We include, for reference, a listing of the fields of each top-level
4081 PDU, as well as their default settings.
4083 <table frame="top" id="asn.default.initialize.request">
4084 <title>Default settings for PDU Initialize Request</title>
4086 <colspec colwidth="7*" colname="field"></colspec>
4087 <colspec colwidth="5*" colname="type"></colspec>
4088 <colspec colwidth="7*" colname="value"></colspec>
4091 <entry>Field</entry>
4093 <entry>Default Value</entry>
4098 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4101 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4104 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4107 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4110 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4113 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4116 implementationId</entry><entry>char*</entry><entry>"81"
4119 implementationName</entry><entry>char*</entry><entry>"YAZ"
4122 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4125 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4128 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4133 <table frame="top" id="asn.default.initialize.response">
4134 <title>Default settings for PDU Initialize Response</title>
4136 <colspec colwidth="7*" colname="field"></colspec>
4137 <colspec colwidth="5*" colname="type"></colspec>
4138 <colspec colwidth="7*" colname="value"></colspec>
4141 <entry>Field</entry>
4143 <entry>Default Value</entry>
4148 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4151 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4154 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4157 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4160 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4163 result</entry><entry>Odr_bool</entry><entry>TRUE
4166 implementationId</entry><entry>char*</entry><entry>"id)"
4169 implementationName</entry><entry>char*</entry><entry>"YAZ"
4172 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4175 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4178 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4183 <table frame="top" id="asn.default.search.request">
4184 <title>Default settings for PDU Search Request</title>
4186 <colspec colwidth="7*" colname="field"></colspec>
4187 <colspec colwidth="5*" colname="type"></colspec>
4188 <colspec colwidth="7*" colname="value"></colspec>
4191 <entry>Field</entry>
4193 <entry>Default Value</entry>
4198 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4201 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4204 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4207 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4210 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4213 resultSetName</entry><entry>char *</entry><entry>"default"
4216 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4219 databaseNames</entry><entry>char **</entry><entry>NULL
4222 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4226 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4230 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4233 query</entry><entry>Z_Query</entry><entry>NULL
4236 additionalSearchInfo</entry><entry>Z_OtherInformation
4240 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4245 <table frame="top" id="asn.default.search.response">
4246 <title>Default settings for PDU Search Response</title>
4248 <colspec colwidth="7*" colname="field"></colspec>
4249 <colspec colwidth="5*" colname="type"></colspec>
4250 <colspec colwidth="7*" colname="value"></colspec>
4253 <entry>Field</entry>
4255 <entry>Default Value</entry>
4260 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4263 resultCount</entry><entry>Odr_int</entry><entry>0
4266 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4269 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4272 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4275 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4278 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4281 records</entry><entry>Z_Records</entry><entry>NULL
4284 additionalSearchInfo</entry>
4285 <entry>Z_OtherInformation</entry><entry>NULL
4288 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4293 <table frame="top" id="asn.default.present.request">
4294 <title>Default settings for PDU Present Request</title>
4296 <colspec colwidth="7*" colname="field"></colspec>
4297 <colspec colwidth="5*" colname="type"></colspec>
4298 <colspec colwidth="7*" colname="value"></colspec>
4301 <entry>Field</entry>
4303 <entry>Default Value</entry>
4308 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4311 resultSetId</entry><entry>char*</entry><entry>"default"
4314 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4317 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4320 num_ranges</entry><entry>Odr_int</entry><entry>0
4323 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4326 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4329 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4332 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4335 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4338 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4341 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4346 <table frame="top" id="asn.default.present.response">
4347 <title>Default settings for PDU Present Response</title>
4349 <colspec colwidth="7*" colname="field"></colspec>
4350 <colspec colwidth="5*" colname="type"></colspec>
4351 <colspec colwidth="7*" colname="value"></colspec>
4354 <entry>Field</entry>
4356 <entry>Default Value</entry>
4361 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4364 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4367 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4370 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4373 records</entry><entry>Z_Records</entry><entry>NULL
4376 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4381 <table frame="top" id="asn.default.delete.result.set.request">
4382 <title>Default settings for Delete Result Set Request</title>
4384 <colspec colwidth="7*" colname="field"></colspec>
4385 <colspec colwidth="5*" colname="type"></colspec>
4386 <colspec colwidth="7*" colname="value"></colspec>
4389 <entry>Field</entry>
4391 <entry>Default Value</entry>
4395 <row><entry>referenceId
4396 </entry><entry>Z_ReferenceId</entry><entry>NULL
4399 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4402 num_ids</entry><entry>Odr_int</entry><entry>0
4405 resultSetList</entry><entry>char**</entry><entry>NULL
4408 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4413 <table frame="top" id="asn.default.delete.result.set.response">
4414 <title>Default settings for Delete Result Set Response</title>
4416 <colspec colwidth="7*" colname="field"></colspec>
4417 <colspec colwidth="5*" colname="type"></colspec>
4418 <colspec colwidth="7*" colname="value"></colspec>
4421 <entry>Field</entry>
4423 <entry>Default Value</entry>
4428 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4431 deleteOperationStatus</entry><entry>Odr_int</entry>
4432 <entry>Z_DeleteStatus_success</entry></row>
4434 num_statuses</entry><entry>Odr_int</entry><entry>0
4437 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4440 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4443 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4446 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4449 deleteMessage</entry><entry>char*</entry><entry>NULL
4452 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4457 <table frame="top" id="asn.default.scan.request">
4458 <title>Default settings for Scan Request</title>
4460 <colspec colwidth="7*" colname="field"></colspec>
4461 <colspec colwidth="5*" colname="type"></colspec>
4462 <colspec colwidth="7*" colname="value"></colspec>
4465 <entry>Field</entry>
4467 <entry>Default Value</entry>
4472 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4475 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4478 databaseNames</entry><entry>char**</entry><entry>NULL
4481 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4484 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4485 </entry><entry>NULL</entry></row>
4487 stepSize</entry><entry>Odr_int</entry><entry>NULL
4490 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4493 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4496 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4501 <table frame="top" id="asn.default.scan.response">
4502 <title>Default settings for Scan Response</title>
4504 <colspec colwidth="7*" colname="field"></colspec>
4505 <colspec colwidth="5*" colname="type"></colspec>
4506 <colspec colwidth="7*" colname="value"></colspec>
4509 <entry>Field</entry>
4511 <entry>Default Value</entry>
4516 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4519 stepSize</entry><entry>Odr_int</entry><entry>NULL
4522 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4525 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4528 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4531 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4534 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4537 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4542 <table frame="top" id="asn.default.trigger.resource.control.request">
4543 <title>Default settings for Trigger Resource Control Request</title>
4545 <colspec colwidth="7*" colname="field"></colspec>
4546 <colspec colwidth="5*" colname="type"></colspec>
4547 <colspec colwidth="7*" colname="value"></colspec>
4550 <entry>Field</entry>
4552 <entry>Default Value</entry>
4557 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4560 requestedAction</entry><entry>Odr_int</entry><entry>
4561 Z_TriggerResourceCtrl_resou..
4564 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4567 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4570 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4575 <table frame="top" id="asn.default.resource.control.request">
4576 <title>Default settings for Resource Control Request</title>
4578 <colspec colwidth="7*" colname="field"></colspec>
4579 <colspec colwidth="5*" colname="type"></colspec>
4580 <colspec colwidth="7*" colname="value"></colspec>
4583 <entry>Field</entry>
4585 <entry>Default Value</entry>
4590 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4593 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4596 resourceReport</entry><entry>Z_External</entry><entry>NULL
4599 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4602 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4605 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4608 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4613 <table frame="top" id="asn.default.resource.control.response">
4614 <title>Default settings for Resource Control Response</title>
4616 <colspec colwidth="7*" colname="field"></colspec>
4617 <colspec colwidth="5*" colname="type"></colspec>
4618 <colspec colwidth="7*" colname="value"></colspec>
4621 <entry>Field</entry>
4623 <entry>Default Value</entry>
4628 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4631 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4634 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4637 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4642 <table frame="top" id="asn.default.access.control.request">
4643 <title>Default settings for Access Control Request</title>
4645 <colspec colwidth="7*" colname="field"></colspec>
4646 <colspec colwidth="5*" colname="type"></colspec>
4647 <colspec colwidth="7*" colname="value"></colspec>
4650 <entry>Field</entry>
4652 <entry>Default Value</entry>
4657 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4660 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4663 u</entry><entry>union</entry><entry>NULL
4666 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4671 <table frame="top" id="asn.default.access.control.response">
4672 <title>Default settings for Access Control Response</title>
4674 <colspec colwidth="7*" colname="field"></colspec>
4675 <colspec colwidth="5*" colname="type"></colspec>
4676 <colspec colwidth="7*" colname="value"></colspec>
4679 <entry>Field</entry>
4681 <entry>Default Value</entry>
4686 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4689 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4692 u</entry><entry>union</entry><entry>NULL
4695 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4698 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4703 <table frame="top" id="asn.default.segment">
4704 <title>Default settings for Segment</title>
4706 <colspec colwidth="7*" colname="field"></colspec>
4707 <colspec colwidth="5*" colname="type"></colspec>
4708 <colspec colwidth="7*" colname="value"></colspec>
4711 <entry>Field</entry>
4713 <entry>Default Value</entry>
4718 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4721 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4724 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4727 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4729 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4734 <table frame="top" id="asn.default.close">
4735 <title>Default settings for Close</title>
4737 <colspec colwidth="7*" colname="field"></colspec>
4738 <colspec colwidth="5*" colname="type"></colspec>
4739 <colspec colwidth="7*" colname="value"></colspec>
4742 <entry>Field</entry>
4744 <entry>Default Value</entry>
4749 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4752 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4755 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4758 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4761 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4764 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4772 <title>SOAP and SRU</title>
4773 <sect1 id="soap.introduction">
4774 <title>Introduction</title>
4776 &yaz; uses a very simple implementation of
4777 <ulink url="&url.soap;">SOAP</ulink> that only,
4778 currenly, supports what is sufficient to offer SRU SOAP functionality.
4779 The implementation uses the
4780 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4781 libxml2 to encode and decode SOAP packages.
4784 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4785 simple C structs to represent SOAP packages as well as
4789 <sect1 id="soap.http">
4792 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4793 relatively easy to change that.
4796 The following definition of <literal>Z_GDU</literal> (Generic Data
4797 Unit) allows for both HTTP and Z39.50 in one packet.
4800 #include <yaz/zgdu.h>
4802 #define Z_GDU_Z3950 1
4803 #define Z_GDU_HTTP_Request 2
4804 #define Z_GDU_HTTP_Response 3
4809 Z_HTTP_Request *HTTP_Request;
4810 Z_HTTP_Response *HTTP_Response;
4815 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4816 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4818 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4819 is the HTTP Request and Response respectively.
4822 <sect1 id="soap.xml">
4823 <title>SOAP Packages</title>
4825 Every SOAP package in &yaz; is represented as follows:
4827 #include <yaz/soap.h>
4841 #define Z_SOAP_fault 1
4842 #define Z_SOAP_generic 2
4843 #define Z_SOAP_error 3
4847 Z_SOAP_Fault *fault;
4848 Z_SOAP_Generic *generic;
4849 Z_SOAP_Fault *soap_error;
4856 The <literal>fault</literal> and <literal>soap_error</literal>
4857 arms represent both a SOAP fault - struct
4858 <literal>Z_SOAP_Fault</literal>. Any other generic
4859 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
4862 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
4863 is the namespace for SOAP itself and reflects the SOAP
4864 version. For version 1.1 it is
4865 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
4866 for version 1.2 it is
4867 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
4870 int z_soap_codec(ODR o, Z_SOAP **pp,
4871 char **content_buf, int *content_len,
4872 Z_SOAP_Handler *handlers);
4875 The <literal>content_buf</literal> and <literal>content_len</literal>
4876 is XML buffer and length of buffer respectively.
4879 The <literal>handlers</literal> is a list of SOAP codec
4880 handlers - one handler for each service namespace. For SRU SOAP, the
4881 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
4884 When decoding, the <function>z_soap_codec</function>
4885 inspects the XML content
4886 and tries to match one of the services namespaces of the
4887 supplied handlers. If there is a match a handler function
4888 is invoked which decodes that particular SOAP package.
4889 If successful, the returned <literal>Z_SOAP</literal> package will be
4890 of type <literal>Z_SOAP_Generic</literal>.
4891 Member <literal>no</literal> is
4892 set the offset of handler that matched; <literal>ns</literal>
4893 is set to namespace of matching handler; the void pointer
4894 <literal>p</literal> is set to the C data structure assocatiated
4898 When a NULL namespace is met (member <literal>ns</literal> bwlow),
4899 that specifies end-of-list.
4902 Each handler is defined as follows:
4910 The <literal>ns</literal> is namespace of service associated with
4911 handler <literal>f</literal>. <literal>client_data</literal>
4912 is user-defined data which is passed to handler.
4915 The prototype for a SOAP service handler is:
4917 int handler(ODR o, void * ptr, void **handler_data,
4918 void *client_data, const char *ns);
4920 The <parameter>o</parameter> specifies the mode (decode/encode)
4921 as usual. The second argument, <parameter>ptr</parameter>,
4922 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
4923 and is a pointer to the <literal>Body</literal> element
4924 of the SOAP package. The <parameter>handler_data</parameter>
4925 is an opaque pointer to a C definitions associated with the
4926 SOAP service. <parameter>client_data</parameter> is the pointer
4927 which was set as part of the <literal>Z_SOAP_handler</literal>.
4928 Finally, <parameter>ns</parameter> the service namespace.
4931 <sect1 id="soap.srw">
4934 SRU SOAP is just one implementation of a SOAP handler as described
4935 in the previous section.
4936 The encoder/decoder handler for SRU is defined as
4939 #include <yaz/srw.h>
4941 int yaz_srw_codec(ODR o, void * pptr,
4942 Z_SRW_GDU **handler_data,
4943 void *client_data, const char *ns);
4945 Here, <literal>Z_SRW_GDU</literal> is either
4946 searchRetrieveRequest or a searchRetrieveResponse.
4950 The xQuery and xSortKeys are not handled yet by
4951 the SRW implementation of &yaz;. Explain is also missing.
4952 Future versions of &yaz; will include these features.
4956 The definition of searchRetrieveRequest is:
4960 #define Z_SRW_query_type_cql 1
4961 #define Z_SRW_query_type_xcql 2
4962 #define Z_SRW_query_type_pqf 3
4970 #define Z_SRW_sort_type_none 1
4971 #define Z_SRW_sort_type_sort 2
4972 #define Z_SRW_sort_type_xSort 3
4980 int *maximumRecords;
4982 char *recordPacking;
4984 } Z_SRW_searchRetrieveRequest;
4986 Please observe that data of type xsd:string is represented
4987 as a char pointer (<literal>char *</literal>). A null pointer
4988 means that the element is absent.
4989 Data of type xsd:integer is representd as a pointer to
4990 an int (<literal>int *</literal>). Again, a null pointer
4991 us used for absent elements.
4994 The SearchRetrieveResponse has the following definition.
4997 int * numberOfRecords;
4999 int * resultSetIdleTime;
5001 Z_SRW_record *records;
5004 Z_SRW_diagnostic *diagnostics;
5005 int num_diagnostics;
5006 int *nextRecordPosition;
5007 } Z_SRW_searchRetrieveResponse;
5009 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
5010 is number of returned records and diagnostics respectively and also
5011 correspond to the "size of" arrays <literal>records</literal>
5012 and <literal>diagnostics</literal>.
5015 A retrieval record is defined as follows:
5019 char *recordData_buf;
5021 int *recordPosition;
5024 The record data is defined as a buffer of some length so that
5025 data can be of any type. SRW 1.0 currenly doesn't allow for this
5026 (only XML), but future versions might do.
5029 And, a diagnostic as:
5039 <chapter id="tools">
5040 <title>Supporting Tools</title>
5042 In support of the service API - primarily the ASN module, which
5043 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5044 a collection of tools that support the development of applications.
5046 <sect1 id="tools.query">
5047 <title>Query Syntax Parsers</title>
5049 Since the type-1 (RPN) query structure has no direct, useful string
5050 representation, every origin application needs to provide some form of
5051 mapping from a local query notation or representation to a
5052 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5053 construct the query manually, perhaps using
5054 <function>odr_malloc()</function> to simplify memory management.
5055 The &yaz; distribution includes three separate, query-generating tools
5056 that may be of use to you.
5059 <title>Prefix Query Format</title>
5061 Since RPN or reverse polish notation is really just a fancy way of
5062 describing a suffix notation format (operator follows operands), it
5063 would seem that the confusion is total when we now introduce a prefix
5064 notation for RPN. The reason is one of simple laziness - it's somewhat
5065 simpler to interpret a prefix format, and this utility was designed
5066 for maximum simplicity, to provide a baseline representation for use
5067 in simple test applications and scripting environments (like Tcl). The
5068 demonstration client included with YAZ uses the PQF.
5072 The PQF have been adopted by other parties developing Z39.50
5073 software. It is often referred to as Prefix Query Notation
5078 The PQF is defined by the pquery module in the YAZ library.
5079 There are two sets of function that have similar behavior. First
5080 set operates on a PQF parser handle, second set doesn't. First set
5081 set of functions are more flexible than the second set. Second set
5082 is obsolete and is only provided to ensure backwards compatibility.
5085 First set of functions all operate on a PQF parser handle:
5088 #include <yaz/pquery.h>
5090 YAZ_PQF_Parser yaz_pqf_create(void);
5092 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5094 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5096 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5097 Odr_oid **attributeSetId, const char *qbuf);
5099 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5102 A PQF parser is created and destructed by functions
5103 <function>yaz_pqf_create</function> and
5104 <function>yaz_pqf_destroy</function> respectively.
5105 Function <function>yaz_pqf_parse</function> parses query given
5106 by string <literal>qbuf</literal>. If parsing was successful,
5107 a Z39.50 RPN Query is returned which is created using ODR stream
5108 <literal>o</literal>. If parsing failed, a NULL pointer is
5110 Function <function>yaz_pqf_scan</function> takes a scan query in
5111 <literal>qbuf</literal>. If parsing was successful, the function
5112 returns attributes plus term pointer and modifies
5113 <literal>attributeSetId</literal> to hold attribute set for the
5114 scan request - both allocated using ODR stream <literal>o</literal>.
5115 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5116 Error information for bad queries can be obtained by a call to
5117 <function>yaz_pqf_error</function> which returns an error code and
5118 modifies <literal>*msg</literal> to point to an error description,
5119 and modifies <literal>*off</literal> to the offset within last
5120 query were parsing failed.
5123 The second set of functions are declared as follows:
5126 #include <yaz/pquery.h>
5128 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5130 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5131 Odr_oid **attributeSetP, const char *qbuf);
5133 int p_query_attset(const char *arg);
5136 The function <function>p_query_rpn()</function> takes as arguments an
5137 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5138 to provide a memory source (the structure created is released on
5139 the next call to <function>odr_reset()</function> on the stream), a
5140 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5141 <token>PROTO_SR</token>), an attribute set reference, and
5142 finally a null-terminated string holding the query string.
5145 If the parse went well, <function>p_query_rpn()</function> returns a
5146 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5147 placed directly into a <literal>Z_SearchRequest</literal>.
5148 If parsing failed, due to syntax error, a NULL pointer is returned.
5151 The <literal>p_query_attset</literal> specifies which attribute set
5152 to use if the query doesn't specify one by the
5153 <literal>@attrset</literal> operator.
5154 The <literal>p_query_attset</literal> returns 0 if the argument is a
5155 valid attribute set specifier; otherwise the function returns -1.
5158 The grammar of the PQF is as follows:
5161 query ::= top-set query-struct.
5163 top-set ::= [ '@attrset' string ]
5165 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5167 attr-spec ::= '@attr' [ string ] string query-struct
5169 complex ::= operator query-struct query-struct.
5171 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5173 simple ::= result-set | term.
5175 result-set ::= '@set' string.
5179 proximity ::= exclusion distance ordered relation which-code unit-code.
5181 exclusion ::= '1' | '0' | 'void'.
5183 distance ::= integer.
5185 ordered ::= '1' | '0'.
5187 relation ::= integer.
5189 which-code ::= 'known' | 'private' | integer.
5191 unit-code ::= integer.
5193 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5196 You will note that the syntax above is a fairly faithful
5197 representation of RPN, except for the Attribute, which has been
5198 moved a step away from the term, allowing you to associate one or more
5199 attributes with an entire query structure. The parser will
5200 automatically apply the given attributes to each term as required.
5203 The @attr operator is followed by an attribute specification
5204 (<literal>attr-spec</literal> above). The specification consists
5205 of an optional attribute set, an attribute type-value pair and
5206 a sub-query. The attribute type-value pair is packed in one string:
5207 an attribute type, an equals sign, and an attribute value, like this:
5208 <literal>@attr 1=1003</literal>.
5209 The type is always an integer but the value may be either an
5210 integer or a string (if it doesn't start with a digit character).
5211 A string attribute-value is encoded as a Type-1 ``complex''
5212 attribute with the list of values containing the single string
5213 specified, and including no semantic indicators.
5216 Version 3 of the Z39.50 specification defines various encoding of terms.
5217 Use <literal>@term </literal> <replaceable>type</replaceable>
5218 <replaceable>string</replaceable>,
5219 where type is one of: <literal>general</literal>,
5220 <literal>numeric</literal> or <literal>string</literal>
5221 (for InternationalString).
5222 If no term type has been given, the <literal>general</literal> form
5223 is used. This is the only encoding allowed in both versions 2 and 3
5224 of the Z39.50 standard.
5226 <sect3 id="PQF-prox">
5227 <title>Using Proximity Operators with PQF</title>
5230 This is an advanced topic, describing how to construct
5231 queries that make very specific requirements on the
5232 relative location of their operands.
5233 You may wish to skip this section and go straight to
5234 <link linkend="pqf-examples">the example PQF queries</link>.
5239 Most Z39.50 servers do not support proximity searching, or
5240 support only a small subset of the full functionality that
5241 can be expressed using the PQF proximity operator. Be
5242 aware that the ability to <emphasis>express</emphasis> a
5243 query in PQF is no guarantee that any given server will
5244 be able to <emphasis>execute</emphasis> it.
5250 The proximity operator <literal>@prox</literal> is a special
5251 and more restrictive version of the conjunction operator
5252 <literal>@and</literal>. Its semantics are described in
5253 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5254 can be read on-line at
5255 <ulink url="&url.z39.50.proximity;"/>
5258 In PQF, the proximity operation is represented by a sequence
5261 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5263 in which the meanings of the parameters are as described in in
5264 the standard, and they can take the following values:
5267 <formalpara><title>exclusion</title>
5269 0 = false (i.e. the proximity condition specified by the
5270 remaining parameters must be satisfied) or
5271 1 = true (the proximity condition specified by the
5272 remaining parameters must <emphasis>not</emphasis> be
5278 <formalpara><title>distance</title><para>
5279 An integer specifying the difference between the locations
5280 of the operands: e.g. two adjacent words would have
5281 distance=1 since their locations differ by one unit.
5283 </formalpara></listitem>
5285 <formalpara><title>ordered</title><para>
5286 1 = ordered (the operands must occur in the order the
5287 query specifies them) or
5288 0 = unordered (they may appear in either order).
5293 <formalpara><title>relation</title><para>
5294 Recognised values are
5296 2 (lessThanOrEqual),
5298 4 (greaterThanOrEqual),
5305 <formalpara><title>which-code</title><para>
5306 <literal>known</literal>
5308 <literal>k</literal>
5309 (the unit-code parameter is taken from the well-known list
5310 of alternatives described in below) or
5311 <literal>private</literal>
5313 <literal>p</literal>
5314 (the unit-code paramater has semantics specific to an
5315 out-of-band agreement such as a profile).
5320 <formalpara><title>unit-code</title><para>
5321 If the which-code parameter is <literal>known</literal>
5322 then the recognised values are
5332 10 (elementType) and
5334 If which-code is <literal>private</literal> then the
5335 acceptable values are determined by the profile.
5340 (The numeric values of the relation and well-known unit-code
5341 parameters are taken straight from
5342 <ulink url="&url.z39.50.proximity.asn1;"
5343 >the ASN.1</ulink> of the proximity structure in the standard.)
5346 <sect3 id="pqf-examples">
5347 <title>PQF queries</title>
5348 <example id="example.pqf.simple.terms">
5349 <title>PQF queries using simple terms</title>
5358 <example id="pqf.example.pqf.boolean.operators">
5359 <title>PQF boolean operators</title>
5362 @or "dylan" "zimmerman"
5364 @and @or dylan zimmerman when
5366 @and when @or dylan zimmerman
5370 <example id="example.pqf.result.sets">
5371 <title>PQF references to result sets</title>
5376 @and @set seta @set setb
5380 <example id="example.pqf.attributes">
5381 <title>Attributes for terms</title>
5386 @attr 1=4 @attr 4=1 "self portrait"
5388 @attrset exp1 @attr 1=1 CategoryList
5390 @attr gils 1=2008 Copenhagen
5392 @attr 1=/book/title computer
5396 <example id="example.pqf.proximity">
5397 <title>PQF Proximity queries</title>
5400 @prox 0 3 1 2 k 2 dylan zimmerman
5402 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5403 distance, ordered, relation, which-code and unit-code, in that
5407 <para>exclusion = 0: the proximity condition must hold</para>
5410 <para>distance = 3: the terms must be three units apart</para>
5414 ordered = 1: they must occur in the order they are specified
5419 relation = 2: lessThanOrEqual (to the distance of 3 units)
5424 which-code is ``known'', so the standard unit-codes are used
5428 <para>unit-code = 2: word.</para>
5431 So the whole proximity query means that the words
5432 <literal>dylan</literal> and <literal>zimmerman</literal> must
5433 both occur in the record, in that order, differing in position
5434 by three or fewer words (i.e. with two or fewer words between
5435 them.) The query would find ``Bob Dylan, aka. Robert
5436 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5437 since the distance in this case is four.
5440 <example id="example.pqf.search.term.type">
5441 <title>PQF specification of search term type</title>
5444 @term string "a UTF-8 string, maybe?"
5448 <example id="example.pqf.mixed.queries">
5449 <title>PQF mixed queries</title>
5452 @or @and bob dylan @set Result-1
5454 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5456 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5458 The last of these examples is a spatial search: in
5459 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5460 >the GILS attribute set</ulink>,
5462 2038 indicates West Bounding Coordinate and
5463 2030 indicates East Bounding Coordinate,
5464 so the query is for areas extending from -114 degrees
5465 to no more than -109 degrees.
5470 <sect2 id="CCL"><title>CCL</title>
5472 Not all users enjoy typing in prefix query structures and numerical
5473 attribute values, even in a minimalistic test client. In the library
5474 world, the more intuitive Common Command Language - CCL (ISO 8777)
5475 has enjoyed some popularity - especially before the widespread
5476 availability of graphical interfaces. It is still useful in
5477 applications where you for some reason or other need to provide a
5478 symbolic language for expressing boolean query structures.
5480 <sect3 id="ccl.syntax">
5481 <title>CCL Syntax</title>
5483 The CCL parser obeys the following grammar for the FIND argument.
5484 The syntax is annotated by in the lines prefixed by
5485 <literal>--</literal>.
5488 CCL-Find ::= CCL-Find Op Elements
5491 Op ::= "and" | "or" | "not"
5492 -- The above means that Elements are separated by boolean operators.
5494 Elements ::= '(' CCL-Find ')'
5497 | Qualifiers Relation Terms
5498 | Qualifiers Relation '(' CCL-Find ')'
5499 | Qualifiers '=' string '-' string
5500 -- Elements is either a recursive definition, a result set reference, a
5501 -- list of terms, qualifiers followed by terms, qualifiers followed
5502 -- by a recursive definition or qualifiers in a range (lower - upper).
5504 Set ::= 'set' = string
5505 -- Reference to a result set
5507 Terms ::= Terms Prox Term
5509 -- Proximity of terms.
5511 Term ::= Term string
5513 -- This basically means that a term may include a blank
5515 Qualifiers ::= Qualifiers ',' string
5517 -- Qualifiers is a list of strings separated by comma
5519 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5520 -- Relational operators. This really doesn't follow the ISO8777
5524 -- Proximity operator
5527 <example id="example.ccl.queries">
5528 <title>CCL queries</title>
5530 The following queries are all valid:
5541 (dylan and bob) or set=1
5550 Assuming that the qualifiers <literal>ti</literal>,
5551 <literal>au</literal>
5552 and <literal>date</literal> are defined we may use:
5557 au=(bob dylan and slow train coming)
5559 date>1980 and (ti=((self portrait)))
5563 <sect3 id="ccl.qualifiers">
5564 <title>CCL Qualifiers</title>
5566 Qualifiers are used to direct the search to a particular searchable
5567 index, such as title (ti) and author indexes (au). The CCL standard
5568 itself doesn't specify a particular set of qualifiers, but it does
5569 suggest a few short-hand notations. You can customize the CCL parser
5570 to support a particular set of qualifiers to reflect the current target
5571 profile. Traditionally, a qualifier would map to a particular
5572 use-attribute within the BIB-1 attribute set. It is also
5573 possible to set other attributes, such as the structure
5577 A CCL profile is a set of predefined CCL qualifiers that may be
5578 read from a file or set in the CCL API.
5579 The YAZ client reads its CCL qualifiers from a file named
5580 <filename>default.bib</filename>. There are four types of
5581 lines in a CCL profile: qualifier specification,
5582 qualifier alias, comments and directives.
5584 <sect4 id="ccl.qualifier.specification">
5585 <title>Qualifier specification</title>
5587 A qualifier specification is of the form:
5590 <replaceable>qualifier-name</replaceable>
5591 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5592 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5595 where <replaceable>qualifier-name</replaceable> is the name of the
5596 qualifier to be used (eg. <literal>ti</literal>),
5597 <replaceable>type</replaceable> is attribute type in the attribute
5598 set (Bib-1 is used if no attribute set is given) and
5599 <replaceable>val</replaceable> is attribute value.
5600 The <replaceable>type</replaceable> can be specified as an
5601 integer or as it be specified either as a single-letter:
5602 <literal>u</literal> for use,
5603 <literal>r</literal> for relation,<literal>p</literal> for position,
5604 <literal>s</literal> for structure,<literal>t</literal> for truncation
5605 or <literal>c</literal> for completeness.
5606 The attributes for the special qualifier name <literal>term</literal>
5607 are used when no CCL qualifier is given in a query.
5608 <table id="ccl.common.bib1.attributes">
5609 <title>Common Bib-1 attributes</title>
5611 <colspec colwidth="2*" colname="type"></colspec>
5612 <colspec colwidth="9*" colname="description"></colspec>
5616 <entry>Description</entry>
5621 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5623 Use attribute (1). Common use attributes are
5624 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5625 62 Subject, 1003 Author), 1016 Any. Specify value
5630 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5632 Relation attribute (2). Common values are
5633 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5634 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5638 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5640 Position attribute (3). Values: 1 first in field, 2
5641 first in any subfield, 3 any position in field.
5645 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5647 Structure attribute (4). Values: 1 phrase, 2 word,
5648 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5649 101 name (norm), 102 name (un), 103 structure, 104 urx,
5650 105 free-form-text, 106 document-text, 107 local-number,
5651 108 string, 109 numeric string.
5655 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5657 Truncation attribute (5). Values: 1 right, 2 left,
5658 3 left& right, 100 none, 101 process #, 102 regular-1,
5659 103 regular-2, 104 CCL.
5663 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5665 Completeness attribute (6). Values: 1 incomplete subfield,
5666 2 complete subfield, 3 complete field.
5674 Refer to <xref linkend="bib1"/> or the complete
5675 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5678 It is also possible to specify non-numeric attribute values,
5679 which are used in combination with certain types.
5680 The special combinations are:
5681 <table id="ccl.special.attribute.combos">
5682 <title>Special attribute combos</title>
5684 <colspec colwidth="2*" colname="name"></colspec>
5685 <colspec colwidth="9*" colname="description"></colspec>
5689 <entry>Description</entry>
5694 <entry><literal>s=pw</literal></entry>
5696 The structure is set to either word or phrase depending
5697 on the number of tokens in a term (phrase-word).
5701 <entry><literal>s=al</literal></entry>
5703 Each token in the term is ANDed. (and-list).
5704 This does not set the structure at all.
5707 <row><entry><literal>s=ol</literal></entry>
5709 Each token in the term is ORed. (or-list).
5710 This does not set the structure at all.
5713 <row><entry><literal>s=ag</literal></entry>
5715 Tokens that appears as phrases (with blank in them) gets
5716 structure phrase attached (4=1). Tokens that appear to be words
5717 gets structure word attached (4=2). Phrases and words are
5718 ANDed. This is a variant of s=al and s=pw, with the main
5719 difference that words are not split (with operator AND)
5720 but instead kept in one RPN token. This facility appeared
5724 <row><entry><literal>r=o</literal></entry>
5726 Allows ranges and the operators greather-than, less-than, ...
5728 This sets Bib-1 relation attribute accordingly (relation
5729 ordered). A query construct is only treated as a range if
5730 dash is used and that is surrounded by white-space. So
5731 <literal>-1980</literal> is treated as term
5732 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5733 If <literal>- 1980</literal> is used, however, that is
5737 <row><entry><literal>r=r</literal></entry>
5739 Similar to <literal>r=o</literal> but assumes that terms
5740 are non-negative (not prefixed with <literal>-</literal>).
5741 Thus, a dash will always be treated as a range.
5742 The construct <literal>1980-1990</literal> is
5743 treated as a range with <literal>r=r</literal> but as a
5744 single term <literal>"1980-1990"</literal> with
5745 <literal>r=o</literal>. The special attribute
5746 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5749 <row><entry><literal>r=omiteq</literal></entry>
5751 This will omit relation=equals (@attr 2=3) when r=o / r=r
5752 is used. This is useful for servers that somehow breaks
5753 when an explicit relation=equals is used. Omitting the
5754 relation is usually safe because "equals" is the default
5755 behavior. This tweak was added in YAZ version 5.1.2.
5758 <row><entry><literal>t=l</literal></entry>
5760 Allows term to be left-truncated.
5761 If term is of the form <literal>?x</literal>, the resulting
5762 Type-1 term is <literal>x</literal> and truncation is left.
5765 <row><entry><literal>t=r</literal></entry>
5767 Allows term to be right-truncated.
5768 If term is of the form <literal>x?</literal>, the resulting
5769 Type-1 term is <literal>x</literal> and truncation is right.
5772 <row><entry><literal>t=n</literal></entry>
5774 If term is does not include <literal>?</literal>, the
5775 truncation attribute is set to none (100).
5778 <row><entry><literal>t=b</literal></entry>
5780 Allows term to be both left&right truncated.
5781 If term is of the form <literal>?x?</literal>, the
5782 resulting term is <literal>x</literal> and trunctation is
5783 set to both left&right.
5786 <row><entry><literal>t=x</literal></entry>
5788 Allows masking anywhere in a term, thus fully supporting
5789 # (mask one character) and ? (zero or more of any).
5790 If masking is used, trunction is set to 102 (regexp-1 in term)
5791 and the term is converted accordingly to a regular expression.
5794 <row><entry><literal>t=z</literal></entry>
5796 Allows masking anywhere in a term, thus fully supporting
5797 # (mask one character) and ? (zero or more of any).
5798 If masking is used, trunction is set to 104 (Z39.58 in term)
5799 and the term is converted accordingly to Z39.58 masking term -
5800 actually the same truncation as CCL itself.
5807 <example id="example.ccl.profile">
5808 <title>CCL profile</title>
5810 Consider the following definition:
5820 <literal>ti</literal> and <literal>au</literal> both set
5821 structure attribute to phrase (s=1).
5822 <literal>ti</literal>
5823 sets the use-attribute to 4. <literal>au</literal> sets the
5825 When no qualifiers are used in the query the structure-attribute is
5826 set to free-form-text (105) (rule for <literal>term</literal>).
5827 The <literal>date</literal> sets the relation attribute to
5828 the relation used in the CCL query and sets the use attribute
5832 You can combine attributes. To Search for "ranked title" you
5835 ti,ranked=knuth computer
5837 which will set relation=ranked, use=title, structure=phrase.
5844 is a valid query. But
5852 <sect4 id="ccl.qualifier.alias">
5853 <title>Qualifier alias</title>
5855 A qualifier alias is of the form:
5858 <replaceable>q</replaceable>
5859 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
5862 which declares <replaceable>q</replaceable> to
5863 be an alias for <replaceable>q1</replaceable>,
5864 <replaceable>q2</replaceable>... such that the CCL
5865 query <replaceable>q=x</replaceable> is equivalent to
5866 <replaceable>q1=x or q2=x or ...</replaceable>.
5869 <sect4 id="ccl.comments">
5870 <title>Comments</title>
5872 Lines with white space or lines that begin with
5873 character <literal>#</literal> are treated as comments.
5876 <sect4 id="ccl.directives">
5877 <title>Directives</title>
5879 Directive specifications takes the form
5881 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
5883 <table id="ccl.directives.table">
5884 <title>CCL directives</title>
5886 <colspec colwidth="2*" colname="name"></colspec>
5887 <colspec colwidth="8*" colname="description"></colspec>
5888 <colspec colwidth="1*" colname="default"></colspec>
5892 <entry>Description</entry>
5893 <entry>Default</entry>
5898 <entry>truncation</entry>
5899 <entry>Truncation character</entry>
5900 <entry><literal>?</literal></entry>
5904 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
5905 <entry><literal>#</literal></entry>
5908 <entry>field</entry>
5909 <entry>Specifies how multiple fields are to be
5910 combined. There are two modes: <literal>or</literal>:
5911 multiple qualifier fields are ORed,
5912 <literal>merge</literal>: attributes for the qualifier
5913 fields are merged and assigned to one term.
5915 <entry><literal>merge</literal></entry>
5919 <entry>Specifies if CCL operators and qualifiers should be
5920 compared with case sensitivity or not. Specify 1 for
5921 case sensitive; 0 for case insensitive.</entry>
5922 <entry><literal>1</literal></entry>
5926 <entry>Specifies token for CCL operator AND.</entry>
5927 <entry><literal>and</literal></entry>
5931 <entry>Specifies token for CCL operator OR.</entry>
5932 <entry><literal>or</literal></entry>
5936 <entry>Specifies token for CCL operator NOT.</entry>
5937 <entry><literal>not</literal></entry>
5941 <entry>Specifies token for CCL operator SET.</entry>
5942 <entry><literal>set</literal></entry>
5949 <sect3 id="ccl.api">
5950 <title>CCL API</title>
5952 All public definitions can be found in the header file
5953 <filename>ccl.h</filename>. A profile identifier is of type
5954 <literal>CCL_bibset</literal>. A profile must be created with the call
5955 to the function <function>ccl_qual_mk</function> which returns a profile
5956 handle of type <literal>CCL_bibset</literal>.
5959 To read a file containing qualifier definitions the function
5960 <function>ccl_qual_file</function> may be convenient. This function
5961 takes an already opened <literal>FILE</literal> handle pointer as
5962 argument along with a <literal>CCL_bibset</literal> handle.
5965 To parse a simple string with a FIND query use the function
5968 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
5969 int *error, int *pos);
5972 which takes the CCL profile (<literal>bibset</literal>) and query
5973 (<literal>str</literal>) as input. Upon successful completion the RPN
5974 tree is returned. If an error occur, such as a syntax error, the integer
5975 pointed to by <literal>error</literal> holds the error code and
5976 <literal>pos</literal> holds the offset inside query string in which
5980 An English representation of the error may be obtained by calling
5981 the <literal>ccl_err_msg</literal> function. The error codes are
5982 listed in <filename>ccl.h</filename>.
5985 To convert the CCL RPN tree (type
5986 <literal>struct ccl_rpn_node *</literal>)
5987 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
5988 must be used. This function which is part of YAZ is implemented in
5989 <filename>yaz-ccl.c</filename>.
5990 After calling this function the CCL RPN tree is probably no longer
5991 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
5994 A CCL profile may be destroyed by calling the
5995 <function>ccl_qual_rm</function> function.
5998 The token names for the CCL operators may be changed by setting the
5999 globals (all type <literal>char *</literal>)
6000 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
6001 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
6002 An operator may have aliases, i.e. there may be more than one name for
6003 the operator. To do this, separate each alias with a space character.
6010 <ulink url="&url.cql;">CQL</ulink>
6011 - Common Query Language - was defined for the
6012 <ulink url="&url.sru;">SRU</ulink> protocol.
6013 In many ways CQL has a similar syntax to CCL.
6014 The objective of CQL is different. Where CCL aims to be
6015 an end-user language, CQL is <emphasis>the</emphasis> protocol
6016 query language for SRU.
6020 If you are new to CQL, read the
6021 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6025 The CQL parser in &yaz; provides the following:
6029 It parses and validates a CQL query.
6034 It generates a C structure that allows you to convert
6035 a CQL query to some other query language, such as SQL.
6040 The parser converts a valid CQL query to PQF, thus providing a
6041 way to use CQL for both SRU servers and Z39.50 targets at the
6047 The parser converts CQL to XCQL.
6048 XCQL is an XML representation of CQL.
6049 XCQL is part of the SRU specification. However, since SRU
6050 supports CQL only, we don't expect XCQL to be widely used.
6051 Furthermore, CQL has the advantage over XCQL that it is
6057 <sect3 id="cql.parsing">
6058 <title>CQL parsing</title>
6060 A CQL parser is represented by the <literal>CQL_parser</literal>
6061 handle. Its contents should be considered &yaz; internal (private).
6063 #include <yaz/cql.h>
6065 typedef struct cql_parser *CQL_parser;
6067 CQL_parser cql_parser_create(void);
6068 void cql_parser_destroy(CQL_parser cp);
6070 A parser is created by <function>cql_parser_create</function> and
6071 is destroyed by <function>cql_parser_destroy</function>.
6074 To parse a CQL query string, the following function
6077 int cql_parser_string(CQL_parser cp, const char *str);
6079 A CQL query is parsed by the <function>cql_parser_string</function>
6080 which takes a query <parameter>str</parameter>.
6081 If the query was valid (no syntax errors), then zero is returned;
6082 otherwise -1 is returned to indicate a syntax error.
6086 int cql_parser_stream(CQL_parser cp,
6087 int (*getbyte)(void *client_data),
6088 void (*ungetbyte)(int b, void *client_data),
6091 int cql_parser_stdio(CQL_parser cp, FILE *f);
6093 The functions <function>cql_parser_stream</function> and
6094 <function>cql_parser_stdio</function> parses a CQL query
6095 - just like <function>cql_parser_string</function>.
6096 The only difference is that the CQL query can be
6097 fed to the parser in different ways.
6098 The <function>cql_parser_stream</function> uses a generic
6099 byte stream as input. The <function>cql_parser_stdio</function>
6100 uses a <literal>FILE</literal> handle which is opened for reading.
6103 <sect3 id="cql.tree">
6104 <title>CQL tree</title>
6106 The the query string is valid, the CQL parser
6107 generates a tree representing the structure of the
6112 struct cql_node *cql_parser_result(CQL_parser cp);
6114 <function>cql_parser_result</function> returns the
6115 a pointer to the root node of the resulting tree.
6118 Each node in a CQL tree is represented by a
6119 <literal>struct cql_node</literal>.
6120 It is defined as follows:
6122 #define CQL_NODE_ST 1
6123 #define CQL_NODE_BOOL 2
6124 #define CQL_NODE_SORT 3
6134 struct cql_node *modifiers;
6138 struct cql_node *left;
6139 struct cql_node *right;
6140 struct cql_node *modifiers;
6144 struct cql_node *next;
6145 struct cql_node *modifiers;
6146 struct cql_node *search;
6151 There are three node types: search term (ST), boolean (BOOL)
6153 A modifier is treated as a search term too.
6156 The search term node has five members:
6160 <literal>index</literal>: index for search term.
6161 If an index is unspecified for a search term,
6162 <literal>index</literal> will be NULL.
6167 <literal>index_uri</literal>: index URi for search term
6168 or NULL if none could be resolved for the index.
6173 <literal>term</literal>: the search term itself.
6178 <literal>relation</literal>: relation for search term.
6183 <literal>relation_uri</literal>: relation URI for search term.
6188 <literal>modifiers</literal>: relation modifiers for search
6189 term. The <literal>modifiers</literal> list itself of cql_nodes
6190 each of type <literal>ST</literal>.
6196 The boolean node represents <literal>and</literal>,
6197 <literal>or</literal>, <literal>not</literal> +
6202 <literal>left</literal> and <literal>right</literal>: left
6203 - and right operand respectively.
6208 <literal>modifiers</literal>: proximity arguments.
6214 The sort node represents both the SORTBY clause.
6217 <sect3 id="cql.to.pqf">
6218 <title>CQL to PQF conversion</title>
6220 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6221 that the resulting RPN depends on the Z39.50 target
6222 capabilities (combinations of supported attributes).
6223 In addition, the CQL and SRU operates on index prefixes
6224 (URI or strings), whereas the RPN uses Object Identifiers
6228 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6229 type. It represents a particular mapping between CQL and RPN.
6230 This handle is created and destroyed by the functions:
6232 cql_transform_t cql_transform_open_FILE (FILE *f);
6233 cql_transform_t cql_transform_open_fname(const char *fname);
6234 void cql_transform_close(cql_transform_t ct);
6236 The first two functions create a tranformation handle from
6237 either an already open FILE or from a filename respectively.
6240 The handle is destroyed by <function>cql_transform_close</function>
6241 in which case no further reference of the handle is allowed.
6244 When a <literal>cql_transform_t</literal> handle has been created
6245 you can convert to RPN.
6247 int cql_transform_buf(cql_transform_t ct,
6248 struct cql_node *cn, char *out, int max);
6250 This function converts the CQL tree <literal>cn</literal>
6251 using handle <literal>ct</literal>.
6252 For the resulting PQF, you supply a buffer <literal>out</literal>
6253 which must be able to hold at at least <literal>max</literal>
6257 If conversion failed, <function>cql_transform_buf</function>
6258 returns a non-zero SRU error code; otherwise zero is returned
6259 (conversion successful). The meanings of the numeric error
6260 codes are listed in the SRU specification somewhere (no
6261 direct link anymore).
6264 If conversion fails, more information can be obtained by calling
6266 int cql_transform_error(cql_transform_t ct, char **addinfop);
6268 This function returns the most recently returned numeric
6269 error-code and sets the string-pointer at
6270 <literal>*addinfop</literal> to point to a string containing
6271 additional information about the error that occurred: for
6272 example, if the error code is 15 (``Illegal or unsupported context
6273 set''), the additional information is the name of the requested
6274 context set that was not recognised.
6277 The SRU error-codes may be translated into brief human-readable
6278 error messages using
6280 const char *cql_strerror(int code);
6284 If you wish to be able to produce a PQF result in a different
6285 way, there are two alternatives.
6287 void cql_transform_pr(cql_transform_t ct,
6288 struct cql_node *cn,
6289 void (*pr)(const char *buf, void *client_data),
6292 int cql_transform_FILE(cql_transform_t ct,
6293 struct cql_node *cn, FILE *f);
6295 The former function produces output to a user-defined
6296 output stream. The latter writes the result to an already
6297 open <literal>FILE</literal>.
6300 <sect3 id="cql.to.rpn">
6301 <title>Specification of CQL to RPN mappings</title>
6303 The file supplied to functions
6304 <function>cql_transform_open_FILE</function>,
6305 <function>cql_transform_open_fname</function> follows
6306 a structure found in many Unix utilities.
6307 It consists of mapping specifications - one per line.
6308 Lines starting with <literal>#</literal> are ignored (comments).
6311 Each line is of the form
6313 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6317 An RPN pattern is a simple attribute list. Each attribute pair
6320 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6322 The attribute <replaceable>set</replaceable> is optional.
6323 The <replaceable>type</replaceable> is the attribute type,
6324 <replaceable>value</replaceable> the attribute value.
6327 The character <literal>*</literal> (asterisk) has special meaning
6328 when used in the RPN pattern.
6329 Each occurrence of <literal>*</literal> is substituted with the
6330 CQL matching name (index, relation, qualifier etc).
6331 This facility can be used to copy a CQL name verbatim to the RPN result.
6334 The following CQL patterns are recognized:
6338 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6342 This pattern is invoked when a CQL index, such as
6343 dc.title is converted. <replaceable>set</replaceable>
6344 and <replaceable>name</replaceable> are the context set and index
6346 Typically, the RPN specifies an equivalent use attribute.
6349 For terms not bound by an index the pattern
6350 <literal>index.cql.serverChoice</literal> is used.
6351 Here, the prefix <literal>cql</literal> is defined as
6352 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6353 If this pattern is not defined, the mapping will fail.
6357 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6358 is used when no other index pattern is matched.
6364 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6369 For backwards compatibility, this is recognised as a synonym of
6370 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6376 <literal>relation.</literal><replaceable>relation</replaceable>
6380 This pattern specifies how a CQL relation is mapped to RPN.
6381 <replaceable>pattern</replaceable> is name of relation
6382 operator. Since <literal>=</literal> is used as
6383 separator between CQL pattern and RPN, CQL relations
6384 including <literal>=</literal> cannot be
6385 used directly. To avoid a conflict, the names
6386 <literal>ge</literal>,
6387 <literal>eq</literal>,
6388 <literal>le</literal>,
6389 must be used for CQL operators, greater-than-or-equal,
6390 equal, less-than-or-equal respectively.
6391 The RPN pattern is supposed to include a relation attribute.
6394 For terms not bound by a relation, the pattern
6395 <literal>relation.scr</literal> is used. If the pattern
6396 is not defined, the mapping will fail.
6399 The special pattern, <literal>relation.*</literal> is used
6400 when no other relation pattern is matched.
6406 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6410 This pattern specifies how a CQL relation modifier is mapped to RPN.
6411 The RPN pattern is usually a relation attribute.
6417 <literal>structure.</literal><replaceable>type</replaceable>
6421 This pattern specifies how a CQL structure is mapped to RPN.
6422 Note that this CQL pattern is somewhat to similar to
6423 CQL pattern <literal>relation</literal>.
6424 The <replaceable>type</replaceable> is a CQL relation.
6427 The pattern, <literal>structure.*</literal> is used
6428 when no other structure pattern is matched.
6429 Usually, the RPN equivalent specifies a structure attribute.
6435 <literal>position.</literal><replaceable>type</replaceable>
6439 This pattern specifies how the anchor (position) of
6440 CQL is mapped to RPN.
6441 The <replaceable>type</replaceable> is one
6442 of <literal>first</literal>, <literal>any</literal>,
6443 <literal>last</literal>, <literal>firstAndLast</literal>.
6446 The pattern, <literal>position.*</literal> is used
6447 when no other position pattern is matched.
6453 <literal>set.</literal><replaceable>prefix</replaceable>
6457 This specification defines a CQL context set for a given prefix.
6458 The value on the right hand side is the URI for the set -
6459 <emphasis>not</emphasis> RPN. All prefixes used in
6460 index patterns must be defined this way.
6466 <literal>set</literal>
6470 This specification defines a default CQL context set for index names.
6471 The value on the right hand side is the URI for the set.
6477 <example id="example.cql.to.rpn.mapping">
6478 <title>CQL to RPN mapping file</title>
6480 This simple file defines two context sets, three indexes and three
6481 relations, a position pattern and a default structure.
6483 <programlisting><![CDATA[
6484 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6485 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6487 index.cql.serverChoice = 1=1016
6488 index.dc.title = 1=4
6489 index.dc.subject = 1=21
6495 position.any = 3=3 6=1
6501 With the mappings above, the CQL query
6505 is converted to the PQF:
6507 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6509 by rules <literal>index.cql.serverChoice</literal>,
6510 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6511 <literal>position.any</literal>.
6518 is rejected, since <literal>position.right</literal> is
6524 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6528 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6532 <example id="example.cql.to.rpn.string">
6533 <title>CQL to RPN string attributes</title>
6535 In this example we allow any index to be passed to RPN as
6538 <programlisting><![CDATA[
6539 # Identifiers for prefixes used in this file. (index.*)
6540 set.cql = info:srw/cql-context-set/1/cql-v1.1
6541 set.rpn = http://bogus/rpn
6542 set = http://bogus/rpn
6544 # The default index when none is specified by the query
6545 index.cql.serverChoice = 1=any
6554 The <literal>http://bogus/rpn</literal> context set is also the default
6555 so we can make queries such as
6559 which is converted to
6561 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6565 <example id="example.cql.to.rpn.bathprofile">
6566 <title>CQL to RPN using Bath Profile</title>
6568 The file <filename>etc/pqf.properties</filename> has mappings from
6569 the Bath Profile and Dublin Core to RPN.
6570 If YAZ is installed as a package it's usually located
6571 in <filename>/usr/share/yaz/etc</filename> and part of the
6572 development package, such as <literal>libyaz-dev</literal>.
6576 <sect3 id="cql.xcql">
6577 <title>CQL to XCQL conversion</title>
6579 Conversion from CQL to XCQL is trivial and does not
6580 require a mapping to be defined.
6581 There three functions to choose from depending on the
6582 way you wish to store the resulting output (XML buffer
6585 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6586 void cql_to_xml(struct cql_node *cn,
6587 void (*pr)(const char *buf, void *client_data),
6589 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6591 Function <function>cql_to_xml_buf</function> converts
6592 to XCQL and stores result in a user supplied buffer of a given
6596 <function>cql_to_xml</function> writes the result in
6597 a user defined output stream.
6598 <function>cql_to_xml_stdio</function> writes to a
6602 <sect3 id="rpn.to.cql">
6603 <title>PQF to CQL conversion</title>
6605 Conversion from PQF to CQL is offered by the two functions shown
6606 below. The former uses a generic stream for result. The latter
6607 puts result in a WRBUF (string container).
6609 #include <yaz/rpn2cql.h>
6611 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6612 void (*pr)(const char *buf, void *client_data),
6616 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6620 The configuration is the same as used in CQL to PQF conversions.
6625 <sect1 id="tools.oid">
6626 <title>Object Identifiers</title>
6628 The basic YAZ representation of an OID is an array of integers,
6629 terminated with the value -1. This integer is of type
6630 <literal>Odr_oid</literal>.
6633 Fundamental OID operations and the type <literal>Odr_oid</literal>
6634 are defined in <filename>yaz/oid_util.h</filename>.
6637 An OID can either be declared as a automatic variable or it can
6638 allocated using the memory utilities or ODR/NMEM. It's
6639 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6641 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6643 We can create an OID for the Bib-1 attribute set with:
6645 Odr_oid bib1[OID_SIZE];
6657 And OID may also be filled from a string-based representation using
6658 dots (.). This is achieved by function
6660 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6662 This functions returns 0 if name could be converted; -1 otherwise.
6664 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6666 We can fill the Bib-1 attribute set OID easier with:
6668 Odr_oid bib1[OID_SIZE];
6669 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6674 We can also allocate an OID dynamically on a ODR stream with:
6676 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6678 This creates an OID from string-based representation using dots.
6679 This function take an &odr; stream as parameter. This stream is used to
6680 allocate memory for the data elements, which is released on a
6681 subsequent call to <function>odr_reset()</function> on that stream.
6683 <example id="tools.oid.bib1.3">
6684 <title>Using odr_getoidbystr</title>
6686 We can create a OID for the Bib-1 attribute set with:
6688 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6695 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6697 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6698 converts an OID to the string-based representation using dots.
6699 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6700 string and must be at least <literal>OID_STR_MAX</literal> in size.
6703 OIDs can be copied with <function>oid_oidcpy</function> which takes
6704 two OID lists as arguments. Alternativly, an OID copy can be allocated
6705 on a ODR stream with:
6707 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6711 OIDs can be compared with <function>oid_oidcmp</function> which returns
6712 zero if the two OIDs provided are identical; non-zero otherwise.
6714 <sect2 id="tools.oid.database">
6715 <title>OID database</title>
6717 From YAZ version 3 and later, the oident system has been replaced
6718 by an OID database. OID database is a misnomer .. the old odient
6719 system was also a database.
6722 The OID database is really just a map between named Object Identifiers
6723 (string) and their OID raw equivalents. Most operations either
6724 convert from string to OID or other way around.
6727 Unfortunately, whenever we supply a string we must also specify the
6728 <emphasis>OID class</emphasis>. The class is necessary because some
6729 strings correspond to multiple OIDs. An example of such a string is
6730 <literal>Bib-1</literal> which may either be an attribute-set
6731 or a diagnostic-set.
6734 Applications using the YAZ database should include
6735 <filename>yaz/oid_db.h</filename>.
6738 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6739 Actually that's a pointer. You need not think deal with that.
6740 YAZ has a built-in database which can be considered "constant" for
6742 We can get hold that by using function <function>yaz_oid_std</function>.
6745 All functions with prefix <function>yaz_string_to_oid</function>
6746 converts from class + string to OID. We have variants of this
6747 operation due to different memory allocation strategies.
6750 All functions with prefix
6751 <function>yaz_oid_to_string</function> converts from OID to string
6754 <example id="tools.oid.bib1.4">
6755 <title>Create OID with YAZ DB</title>
6757 We can create an OID for the Bib-1 attribute set on the ODR stream
6761 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6763 This is more complex than using <function>odr_getoidbystr</function>.
6764 You would only use <function>yaz_string_to_oid_odr</function> when the
6765 string (here Bib-1) is supplied by a user or configuration.
6769 <sect2 id="tools.oid.std">
6770 <title>Standard OIDs</title>
6772 All the object identifers in the standard OID database as returned
6773 by <function>yaz_oid_std</function> can referenced directly in a
6774 program as a constant OID.
6775 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6776 followed by OID class (lowercase) - then by OID name (normalized and
6780 See <xref linkend="list-oids"/> for list of all object identifiers
6782 These are declared in <filename>yaz/oid_std.h</filename> but are
6783 included by <filename>yaz/oid_db.h</filename> as well.
6785 <example id="tools.oid.bib1.5">
6786 <title>Use a built-in OID</title>
6788 We can allocate our own OID filled with the constant OID for
6791 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6797 <sect1 id="tools.nmem">
6798 <title>Nibble Memory</title>
6800 Sometimes when you need to allocate and construct a large,
6801 interconnected complex of structures, it can be a bit of a pain to
6802 release the associated memory again. For the structures describing the
6803 Z39.50 PDUs and related structures, it is convenient to use the
6804 memory-management system of the &odr; subsystem (see
6805 <xref linkend="odr.use"/>). However, in some circumstances
6806 where you might otherwise benefit from using a simple nibble memory
6807 management system, it may be impractical to use
6808 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6809 For this purpose, the memory manager which also supports the &odr;
6810 streams is made available in the NMEM module. The external interface
6811 to this module is given in the <filename>nmem.h</filename> file.
6814 The following prototypes are given:
6817 NMEM nmem_create(void);
6818 void nmem_destroy(NMEM n);
6819 void *nmem_malloc(NMEM n, size_t size);
6820 void nmem_reset(NMEM n);
6821 size_t nmem_total(NMEM n);
6822 void nmem_init(void);
6823 void nmem_exit(void);
6826 The <function>nmem_create()</function> function returns a pointer to a
6827 memory control handle, which can be released again by
6828 <function>nmem_destroy()</function> when no longer needed.
6829 The function <function>nmem_malloc()</function> allocates a block of
6830 memory of the requested size. A call to <function>nmem_reset()</function>
6831 or <function>nmem_destroy()</function> will release all memory allocated
6832 on the handle since it was created (or since the last call to
6833 <function>nmem_reset()</function>. The function
6834 <function>nmem_total()</function> returns the number of bytes currently
6835 allocated on the handle.
6838 The nibble memory pool is shared amongst threads. POSIX
6839 mutex'es and WIN32 Critical sections are introduced to keep the
6840 module thread safe. Function <function>nmem_init()</function>
6841 initializes the nibble memory library and it is called automatically
6842 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6843 function <function>DllMain</function> to achieve this. You should
6844 <emphasis>not</emphasis> call <function>nmem_init</function> or
6845 <function>nmem_exit</function> unless you're absolute sure what
6846 you're doing. Note that in previous &yaz; versions you'd have to call
6847 <function>nmem_init</function> yourself.
6850 <sect1 id="tools.log">
6853 &yaz; has evolved a fairly complex log system which should be useful both
6854 for debugging &yaz; itself, debugging applications that use &yaz;, and for
6855 production use of those applications.
6858 The log functions are declared in header <filename>yaz/log.h</filename>
6859 and implemented in <filename>src/log.c</filename>.
6860 Due to name clash with syslog and some math utilities the logging
6861 interface has been modified as of YAZ 2.0.29. The obsolete interface
6862 is still available if in header file <filename>yaz/log.h</filename>.
6863 The key points of the interface are:
6866 void yaz_log(int level, const char *fmt, ...)
6867 void yaz_log_init(int level, const char *prefix, const char *name);
6868 void yaz_log_init_file(const char *fname);
6869 void yaz_log_init_level(int level);
6870 void yaz_log_init_prefix(const char *prefix);
6871 void yaz_log_time_format(const char *fmt);
6872 void yaz_log_init_max_size(int mx);
6874 int yaz_log_mask_str(const char *str);
6875 int yaz_log_module_level(const char *name);
6878 The reason for the whole log module is the <function>yaz_log</function>
6879 function. It takes a bitmask indicating the log levels, a
6880 <literal>printf</literal>-like format string, and a variable number of
6884 The <literal>log level</literal> is a bit mask, that says on which level(s)
6885 the log entry should be made, and optionally set some behaviour of the
6886 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
6887 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
6888 that modify the way the log entry is written:<literal>YLOG_ERRNO,
6889 YLOG_NOTIME, YLOG_FLUSH</literal>.
6890 Most of the rest of the bits are deprecated, and should not be used. Use
6891 the dynamic log levels instead.
6894 Applications that use &yaz;, should not use the LOG_LOG for ordinary
6895 messages, but should make use of the dynamic loglevel system. This consists
6896 of two parts, defining the loglevel and checking it.
6899 To define the log levels, the (main) program should pass a string to
6900 <function>yaz_log_mask_str</function> to define which log levels are to be
6901 logged. This string should be a comma-separated list of log level names,
6902 and can contain both hard-coded names and dynamic ones. The log level
6903 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
6904 for each word it meets, unless the word starts with a '-', in which case it
6905 clears the bit. If the string <literal>'none'</literal> is found,
6906 all bits are cleared. Typically this string comes from the command-line,
6907 often identified by <literal>-v</literal>. The
6908 <function>yaz_log_mask_str</function> returns a log level that should be
6909 passed to <function>yaz_log_init_level</function> for it to take effect.
6912 Each module should check what log bits it should be used, by calling
6913 <function>yaz_log_module_level</function> with a suitable name for the
6914 module. The name is cleared from a preceding path and an extension, if any,
6915 so it is quite possible to use <literal>__FILE__</literal> for it. If the
6916 name has been passed to <function>yaz_log_mask_str</function>, the routine
6917 returns a non-zero bitmask, which should then be used in consequent calls
6918 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
6919 yaz_log, in time-critical places, or when the log entry would take time
6923 Yaz uses the following dynamic log levels:
6924 <literal>server, session, request, requestdetail</literal> for the server
6926 <literal>zoom</literal> for the zoom client api.
6927 <literal>ztest</literal> for the simple test server.
6928 <literal>malloc, nmem, odr, eventl</literal> for internal
6929 debugging of yaz itself.
6930 Of course, any program using yaz is welcome to define as many new
6934 By default the log is written to stderr, but this can be changed by a call
6935 to <function>yaz_log_init_file</function> or
6936 <function>yaz_log_init</function>. If the log is directed to a file, the
6937 file size is checked at every write, and if it exceeds the limit given in
6938 <function>yaz_log_init_max_size</function>, the log is rotated. The
6939 rotation keeps one old version (with a <literal>.1</literal> appended to
6940 the name). The size defaults to 1GB. Setting it to zero will disable the
6944 A typical yaz-log looks like this
6945 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
6946 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
6947 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
6948 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
6949 13:24:13-23/11 yaz-ztest(1) [request] Close OK
6952 The log entries start with a time stamp. This can be omitted by setting the
6953 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
6954 can be hoped to produce identical log files, that are easy to diff. The
6955 format of the time stamp can be set with
6956 <function>yaz_log_time_format</function>, which takes a format string just
6957 like <function>strftime</function>.
6960 Next in a log line comes the prefix, often the name of the program. For
6961 yaz-based servers, it can also contain the session number. Then
6962 comes one or more logbits in square brackets, depending on the logging
6963 level set by <function>yaz_log_init_level</function> and the loglevel
6964 passed to <function>yaz_log_init_level</function>. Finally comes the format
6965 string and additional values passed to <function>yaz_log</function>
6968 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
6969 <literal>loglevel</literal>, will log all the log-level affecting
6970 operations. This can come in handy if you need to know what other log
6971 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
6974 The log system is almost independent of the rest of &yaz;, the only
6975 important dependence is of <filename>nmem</filename>, and that only for
6976 using the semaphore definition there.
6979 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
6980 the same time, the log bit names were changed from
6981 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
6982 to avoid collision with <filename>syslog.h</filename>.
6988 YAZ provides a fast utility for working with MARC records.
6989 Early versions of the MARC utility only allowed decoding of ISO2709.
6990 Today the utility may both encode - and decode to a varity of formats.
6993 #include <yaz/marcdisp.h>
6995 /* create handler */
6996 yaz_marc_t yaz_marc_create(void);
6998 void yaz_marc_destroy(yaz_marc_t mt);
7000 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
7001 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
7002 #define YAZ_MARC_LINE 0
7003 #define YAZ_MARC_SIMPLEXML 1
7004 #define YAZ_MARC_OAIMARC 2
7005 #define YAZ_MARC_MARCXML 3
7006 #define YAZ_MARC_ISO2709 4
7007 #define YAZ_MARC_XCHANGE 5
7008 #define YAZ_MARC_CHECK 6
7009 #define YAZ_MARC_TURBOMARC 7
7010 #define YAZ_MARC_JSON 8
7012 /* supply iconv handle for character set conversion .. */
7013 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
7015 /* set debug level, 0=none, 1=more, 2=even more, .. */
7016 void yaz_marc_debug(yaz_marc_t mt, int level);
7018 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7019 On success, result in *result with size *rsize. */
7020 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7021 const char **result, size_t *rsize);
7023 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7024 On success, result in WRBUF */
7025 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7026 int bsize, WRBUF wrbuf);
7031 The synopsis is just a basic subset of all functionality. Refer
7032 to the actual header file <filename>marcdisp.h</filename> for
7037 A MARC conversion handle must be created by using
7038 <function>yaz_marc_create</function> and destroyed
7039 by calling <function>yaz_marc_destroy</function>.
7042 All other function operate on a <literal>yaz_marc_t</literal> handle.
7043 The output is specified by a call to <function>yaz_marc_xml</function>.
7044 The <literal>xmlmode</literal> must be one of
7047 <term>YAZ_MARC_LINE</term>
7050 A simple line-by-line format suitable for display but not
7051 recommend for further (machine) processing.
7056 <term>YAZ_MARC_MARCXML</term>
7059 <ulink url="&url.marcxml;">MARCXML</ulink>.
7064 <term>YAZ_MARC_ISO2709</term>
7067 ISO2709 (sometimes just referred to as "MARC").
7072 <term>YAZ_MARC_XCHANGE</term>
7075 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7080 <term>YAZ_MARC_CHECK</term>
7083 Pseudo format for validation only. Does not generate
7084 any real output except diagnostics.
7089 <term>YAZ_MARC_TURBOMARC</term>
7092 XML format with same semantics as MARCXML but more compact
7093 and geared towards fast processing with XSLT. Refer to
7094 <xref linkend="tools.turbomarc"/> for more information.
7099 <term>YAZ_MARC_JSON</term>
7102 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7109 The actual conversion functions are
7110 <function>yaz_marc_decode_buf</function> and
7111 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7112 a MARC record. The former function operates on simple buffers, the
7113 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7116 <example id="example.marc.display">
7117 <title>Display of MARC record</title>
7119 The following program snippet illustrates how the MARC API may
7120 be used to convert a MARC record to the line-by-line format:
7121 <programlisting><![CDATA[
7122 void print_marc(const char *marc_buf, int marc_buf_size)
7124 char *result; /* for result buf */
7125 size_t result_len; /* for size of result */
7126 yaz_marc_t mt = yaz_marc_create();
7127 yaz_marc_xml(mt, YAZ_MARC_LINE);
7128 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7129 &result, &result_len);
7130 fwrite(result, result_len, 1, stdout);
7131 yaz_marc_destroy(mt); /* note that result is now freed... */
7137 <sect2 id="tools.turbomarc">
7138 <title>TurboMARC</title>
7140 TurboMARC is yet another XML encoding of a MARC record. The format
7141 was designed for fast processing with XSLT.
7145 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7146 representation. This conversion mostly check the tag of a MARC field
7147 to determine the basic rules in the conversion. This check is
7148 costly when that is tag is encoded as an attribute in MARCXML.
7149 By having the tag value as the element instead, makes processing
7150 many times faster (at least for Libxslt).
7153 TurboMARC is encoded as follows:
7157 Record elements is part of namespace
7158 "<literal>http://www.indexdata.com/turbomarc</literal>".
7163 A record is enclosed in element <literal>r</literal>.
7168 A collection of records is enclosed in element
7169 <literal>collection</literal>.
7174 The leader is encoded as element <literal>l</literal> with the
7175 leader content as its (text) value.
7180 A control field is encoded as element <literal>c</literal> concatenated
7181 with the tag value of the control field if the tag value
7182 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7183 If the tag value do not match the regular expression
7184 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7185 as element <literal>c</literal> and attribute <literal>code</literal>
7186 will hold the tag value.
7187 This rule ensure that in the rare cases where a tag value might
7188 result in a non-wellformed XML YAZ encode it as a coded attribute
7192 The control field content is the the text value of this element.
7193 Indicators are encoded as attribute names
7194 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7195 corresponding values for each indicator.
7200 A data field is encoded as element <literal>d</literal> concatenated
7201 with the tag value of the data field or using the attribute
7202 <literal>code</literal> as described in the rules for control fields.
7203 The children of the data field element is subfield elements.
7204 Each subfield element is encoded as <literal>s</literal>
7205 concatenated with the sub field code.
7206 The text of the subfield element is the contents of the subfield.
7207 Indicators are encoded as attributes for the data field element similar
7208 to the encoding for control fields.
7215 <sect1 id="tools.retrieval">
7216 <title>Retrieval Facility</title>
7218 YAZ version 2.1.20 or later includes a Retrieval facility tool
7219 which allows a SRU/Z39.50 to describe itself and perform record
7220 conversions. The idea is the following:
7224 An SRU/Z39.50 client sends a retrieval request which includes
7225 a combination of the following parameters: syntax (format),
7226 schema (or element set name).
7231 The retrieval facility is invoked with parameters in a
7232 server/proxy. The retrieval facility matches the parameters a set of
7233 "supported" retrieval types.
7234 If there is no match, the retrieval signals an error
7235 (syntax and / or schema not supported).
7240 For a successful match, the backend is invoked with the same
7241 or altered retrieval parameters (syntax, schema). If
7242 a record is received from the backend, it is converted to the
7243 frontend name / syntax.
7248 The resulting record is sent back the client and tagged with
7249 the frontend syntax / schema.
7255 The Retrieval facility is driven by an XML configuration. The
7256 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7257 should be easy to generate both of them from the XML configuration.
7258 (unfortunately the two versions
7259 of ZeeRex differ substantially in this regard).
7261 <sect2 id="tools.retrieval.format">
7262 <title>Retrieval XML format</title>
7264 All elements should be covered by namespace
7265 <literal>http://indexdata.com/yaz</literal> .
7266 The root element node must be <literal>retrievalinfo</literal>.
7269 The <literal>retrievalinfo</literal> must include one or
7270 more <literal>retrieval</literal> elements. Each
7271 <literal>retrieval</literal> defines specific combination of
7272 syntax, name and identifier supported by this retrieval service.
7275 The <literal>retrieval</literal> element may include any of the
7276 following attributes:
7278 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7281 Defines the record syntax. Possible values is any
7282 of the names defined in YAZ' OID database or a raw
7287 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7290 Defines the name of the retrieval format. This can be
7291 any string. For SRU, the value, is equivalent to schema (short-hand);
7292 for Z39.50 it's equivalent to simple element set name.
7293 For YAZ 3.0.24 and later this name may be specified as a glob
7294 expression with operators
7295 <literal>*</literal> and <literal>?</literal>.
7299 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7302 Defines the URI schema name of the retrieval format. This can be
7303 any string. For SRU, the value, is equivalent to URI schema.
7304 For Z39.50, there is no equivalent.
7311 The <literal>retrieval</literal> may include one
7312 <literal>backend</literal> element. If a <literal>backend</literal>
7313 element is given, it specifies how the records are retrieved by
7314 some backend and how the records are converted from the backend to
7318 The attributes, <literal>name</literal> and <literal>syntax</literal>
7319 may be specified for the <literal>backend</literal> element. These
7320 semantics of these attributes is equivalent to those for the
7321 <literal>retrieval</literal>. However, these values are passed to
7325 The <literal>backend</literal> element may includes one or more
7326 conversion instructions (as children elements). The supported
7329 <varlistentry><term><literal>marc</literal></term>
7332 The <literal>marc</literal> element specifies a conversion
7333 to - and from ISO2709 encoded MARC and
7334 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7335 The following attributes may be specified:
7338 <term><literal>inputformat</literal> (REQUIRED)</term>
7341 Format of input. Supported values are
7342 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7343 (MARCXML/MarcXchange) and <literal>json</literal>
7344 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7349 <term><literal>outputformat</literal> (REQUIRED)</term>
7352 Format of output. Supported values are
7353 <literal>line</literal> (MARC line format);
7354 <literal>marcxml</literal> (for MARCXML),
7355 <literal>marc</literal> (ISO2709),
7356 <literal>marcxhcange</literal> (for MarcXchange),
7357 or <literal>json</literal>
7358 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7363 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7366 Encoding of input. For XML input formats, this need not
7367 be given, but for ISO2709 based inputformats, this should
7368 be set to the encoding used. For MARC21 records, a common
7369 inputcharset value would be <literal>marc-8</literal>.
7374 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7377 Encoding of output. If outputformat is XML based, it is
7378 strongly recommened to use <literal>utf-8</literal>.
7387 <term><literal>xslt</literal></term>
7390 The <literal>xslt</literal> element specifies a conversion
7391 via &acro.xslt;. The following attributes may be specified:
7393 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7405 <term><literal>solrmarc</literal></term>
7408 The <literal>solrmarc</literal> decodes solrmarc records.
7409 It assumes that the input is pure solrmarc text (no escaping)
7410 and will convert all sequences of the form #XX; to a single
7411 character of the hexadecimal value as given by XX. The output,
7412 presumably, is a valid ISO2709 buffer.
7415 This conversion is available in YAZ 5.0.21 and later.
7422 <sect2 id="tools.retrieval.examples">
7423 <title>Retrieval Facility Examples</title>
7424 <example id="tools.retrieval.marc21">
7425 <title>MARC21 backend</title>
7427 A typical way to use the retrieval facility is to enable XML
7428 for servers that only supports ISO2709 encoded MARC21 records.
7430 <programlisting><![CDATA[
7432 <retrieval syntax="usmarc" name="F"/>
7433 <retrieval syntax="usmarc" name="B"/>
7434 <retrieval syntax="xml" name="marcxml"
7435 identifier="info:srw/schema/1/marcxml-v1.1">
7436 <backend syntax="usmarc" name="F">
7437 <marc inputformat="marc" outputformat="marcxml"
7438 inputcharset="marc-8"/>
7441 <retrieval syntax="xml" name="dc">
7442 <backend syntax="usmarc" name="F">
7443 <marc inputformat="marc" outputformat="marcxml"
7444 inputcharset="marc-8"/>
7445 <xslt stylesheet="MARC21slim2DC.xsl"/>
7452 This means that our frontend supports:
7456 MARC21 F(ull) records.
7461 MARC21 B(rief) records.
7471 Dublin core records.
7477 <example id="tools.retrieval.marcxml">
7478 <title>MARCXML backend</title>
7480 SRW/SRU and Solr backends returns records in XML.
7481 If they return MARCXML or MarcXchange, the retrieval module
7482 can convert those into ISO2709 formats, most commonly USMARC
7484 In this example, the backend returns MARCXML for schema="marcxml".
7486 <programlisting><![CDATA[
7488 <retrieval syntax="usmarc">
7489 <backend syntax="xml" name="marcxml">
7490 <marc inputformat="xml" outputformat="marc"
7491 outputcharset="marc-8"/>
7494 <retrieval syntax="xml" name="marcxml"
7495 identifier="info:srw/schema/1/marcxml-v1.1"/>
7496 <retrieval syntax="xml" name="dc">
7497 <backend syntax="xml" name="marcxml">
7498 <xslt stylesheet="MARC21slim2DC.xsl"/>
7505 This means that our frontend supports:
7509 MARC21 records (any element set name) in MARC-8 encoding.
7514 MARCXML records for element-set=marcxml
7519 Dublin core records for element-set=dc.
7526 <sect2 id="tools.retrieval.api">
7529 It should be easy to use the retrieval systems from applications. Refer
7531 <filename>yaz/retrieval.h</filename> and
7532 <filename>yaz/record_conv.h</filename>.
7536 <sect1 id="sorting">
7537 <title>Sorting</title>
7539 This chapter describes sorting and how it is supported in YAZ.
7540 Sorting applies to a result-set.
7542 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7543 Z39.50 sorting facility
7545 takes one or more input result-sets
7546 and one result-set as output. The most simple case is that
7547 the input-set is the same as the output-set.
7550 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7551 following a search (two phases).
7554 In SRU/Solr, however, the model is different. Here, sorting is specified
7555 during the the search operation. Note, however, that SRU might
7556 perform sort as separate search, by referring to an existing result-set
7557 in the query (result-set reference).
7560 <title>Using the Z39.50 sort service</title>
7562 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7563 case the sort sequence or sort critiera is using a string notation.
7564 This notation is a one-line notation suitable for being manually
7565 entered or generated and allows for easy logging (one liner).
7566 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7567 function. For yaz-client the sort is performed and specified using
7568 the sort and sort+ commands. For description of the sort criteria notation
7569 refer to the <link linkend="sortspec">sort command</link> in the
7573 The ZOOM API might choose one of several sort strategies for
7574 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7578 <title>Type-7 sort</title>
7580 Type-7 sort is an extension to the Bib-1 based RPN query where the
7581 sort specification is embedded as an Attribute-Plus-Term.
7584 The objectives for introducing Type-7 sorting is that it allows
7585 a client to perform sorting even if it does not implement/support
7586 Z39.50 sort. Virtually all Z39.50 client software supports
7587 RPN queries. It also may improve performance because the sort
7588 critieria is specified along with the search query.
7591 The sort is triggered by the presence of type 7 and the value of type 7
7593 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7596 The value for type 7 is 1 for ascending and 2 for descending.
7598 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7601 only the generic part is handled. If generic sortKey is of type
7602 sortField, then attribute type 1 is present and the value is
7603 sortField (InternationalString). If generic sortKey is of type
7604 sortAttributes, then the attributes in list is used . generic sortKey
7605 of type elementSpec is not supported.
7608 The term in the sorting Attribute-Plus-Term combo should hold
7609 an integer. The value is 0 for primary sorting criteria, 1 for second
7615 <title>Facets</title>
7617 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7620 Like Type-1/RPN, YAZ supports a string notation for specifying
7621 facets. For the API this is performed by
7622 <function>yaz_pqf_parse_facet_list</function>.
7625 For ZOOM C the facets are given by option "facets"
7626 For yaz-client it is used for the facets command.
7629 The grammar of this specification is as follows:
7631 facet-spec ::= facet-list
7633 facet-list ::= facet-list ',' attr-spec | attr-spec
7635 attr-spec ::= attr-spec '@attr' string | '@attr' string
7638 The notation is inspired by PQF. The string following '@attr'
7639 may not include blanks and is of the form
7640 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7641 where <replaceable>type</replaceable> is an integer and
7642 <replaceable>value</replaceable> is a string or an integer.
7645 The Facets specification is not Bib-1. The following types apply:
7647 <table id="facet.attributes">
7648 <title>Facet attributes</title>
7650 <colspec colwidth="2*" colname="type"></colspec>
7651 <colspec colwidth="9*" colname="description"></colspec>
7655 <entry>Description</entry>
7662 Field-name. This is often a string, eg "Author", "Year", etc.
7668 Sort order. Value should be an integer.
7669 Value 0: count descending (frequency). Value 1: alpha ascending.
7675 Number of terms requested.
7690 <title>The ODR Module</title>
7691 <sect1 id="odr.introduction">
7692 <title>Introduction</title>
7694 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7695 to isolate &odr; from the rest of the package - specifically from the
7696 transport interface. &odr; may be used in any context where basic
7697 ASN.1/BER representations are used.
7700 If you are only interested in writing a Z39.50 implementation based on
7701 the PDUs that are already provided with &yaz;, you only need to concern
7702 yourself with the section on managing ODR streams
7703 (<xref linkend="odr.use"/>). Only if you need to
7704 implement ASN.1 beyond that which has been provided, should you
7705 worry about the second half of the documentation
7706 (<xref linkend="odr.programming"/>).
7707 If you use one of the higher-level interfaces, you can skip this
7711 This is important, so we'll repeat it for emphasis: <emphasis>You do
7712 not need to read <xref linkend="odr.programming"/>
7713 to implement Z39.50 with &yaz;.</emphasis>
7716 If you need a part of the protocol that isn't already in &yaz;, you
7717 should contact the authors before going to work on it yourself: We
7718 might already be working on it. Conversely, if you implement a useful
7719 part of the protocol before us, we'd be happy to include it in a
7723 <sect1 id="odr.use">
7724 <title>Using ODR</title>
7725 <sect2 id="odr.streams">
7726 <title>ODR Streams</title>
7728 Conceptually, the ODR stream is the source of encoded data in the
7729 decoding mode; when encoding, it is the receptacle for the encoded
7730 data. Before you can use an ODR stream it must be allocated. This is
7731 done with the function
7734 ODR odr_createmem(int direction);
7737 The <function>odr_createmem()</function> function takes as argument one
7738 of three manifest constants: <literal>ODR_ENCODE</literal>,
7739 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7740 An &odr; stream can be in only one mode - it is not possible to change
7741 its mode once it's selected. Typically, your program will allocate
7742 at least two ODR streams - one for decoding, and one for encoding.
7745 When you're done with the stream, you can use
7748 void odr_destroy(ODR o);
7751 to release the resources allocated for the stream.
7754 <sect2 id="odr.memory.management">
7755 <title id="memory">Memory Management</title>
7757 Two forms of memory management take place in the &odr; system. The first
7758 one, which has to do with allocating little bits of memory (sometimes
7759 quite large bits of memory, actually) when a protocol package is
7760 decoded, and turned into a complex of interlinked structures. This
7761 section deals with this system, and how you can use it for your own
7762 purposes. The next section deals with the memory management which is
7763 required when encoding data - to make sure that a large enough buffer is
7764 available to hold the fully encoded PDU.
7767 The &odr; module has its own memory management system, which is
7768 used whenever memory is required. Specifically, it is used to allocate
7769 space for data when decoding incoming PDUs. You can use the memory
7770 system for your own purposes, by using the function
7773 void *odr_malloc(ODR o, size_t size);
7776 You can't use the normal <function>free(2)</function> routine to free
7777 memory allocated by this function, and &odr; doesn't provide a parallel
7778 function. Instead, you can call
7781 void odr_reset(ODR o);
7784 when you are done with the
7785 memory: Everything allocated since the last call to
7786 <function>odr_reset()</function> is released.
7787 The <function>odr_reset()</function> call is also required to clear
7788 up an error condition on a stream.
7794 size_t odr_total(ODR o);
7797 returns the number of bytes allocated on the stream since the last call to
7798 <function>odr_reset()</function>.
7801 The memory subsystem of &odr; is fairly efficient at allocating and
7802 releasing little bits of memory. Rather than managing the individual,
7803 small bits of space, the system maintains a free-list of larger chunks
7804 of memory, which are handed out in small bits. This scheme is
7805 generally known as a <emphasis>nibble memory</emphasis> system.
7806 It is very useful for maintaining short-lived constructions such
7810 If you want to retain a bit of memory beyond the next call to
7811 <function>odr_reset()</function>, you can use the function
7814 ODR_MEM odr_extract_mem(ODR o);
7817 This function will give you control of the memory recently allocated
7818 on the ODR stream. The memory will live (past calls to
7819 <function>odr_reset()</function>), until you call the function
7822 void odr_release_mem(ODR_MEM p);
7825 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
7826 referencing the memory block for you until you want to release it.
7829 You can use <function>odr_extract_mem()</function> repeatedly between
7830 allocating data, to retain individual control of separate chunks of data.
7833 <sect2 id="odr.encoding.and.decoding">
7834 <title>Encoding and Decoding Data</title>
7836 When encoding data, the ODR stream will write the encoded octet string
7837 in an internal buffer. To retrieve the data, use the function
7840 char *odr_getbuf(ODR o, int *len, int *size);
7843 The integer pointed to by len is set to the length of the encoded
7844 data, and a pointer to that data is returned. <literal>*size</literal>
7845 is set to the size of the buffer (unless <literal>size</literal> is null,
7846 signaling that you are not interested in the size). The next call to
7847 a primitive function using the same &odr; stream will overwrite the
7848 data, unless a different buffer has been supplied using the call
7851 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
7854 which sets the encoding (or decoding) buffer used by
7855 <literal>o</literal> to <literal>buf</literal>, using the length
7856 <literal>len</literal>.
7857 Before a call to an encoding function, you can use
7858 <function>odr_setbuf()</function> to provide the stream with an encoding
7859 buffer of sufficient size (length). The <literal>can_grow</literal>
7860 parameter tells the encoding &odr; stream whether it is allowed to use
7861 <function>realloc(2)</function> to increase the size of the buffer when
7862 necessary. The default condition of a new encoding stream is equivalent
7863 to the results of calling
7866 odr_setbuf(stream, 0, 0, 1);
7869 In this case, the stream will allocate and reallocate memory as
7870 necessary. The stream reallocates memory by repeatedly doubling the
7871 size of the buffer - the result is that the buffer will typically
7872 reach its maximum, working size with only a small number of reallocation
7873 operations. The memory is freed by the stream when the latter is destroyed,
7874 unless it was assigned by the user with the <literal>can_grow</literal>
7875 parameter set to zero (in this case, you are expected to retain
7876 control of the memory yourself).
7879 To assume full control of an encoded buffer, you must first call
7880 <function>odr_getbuf()</function> to fetch the buffer and its length.
7881 Next, you should call <function>odr_setbuf()</function> to provide a
7882 different buffer (or a null pointer) to the stream. In the simplest
7883 case, you will reuse the same buffer over and over again, and you
7884 will just need to call <function>odr_getbuf()</function> after each
7885 encoding operation to get the length and address of the buffer.
7886 Note that the stream may reallocate the buffer during an encoding
7887 operation, so it is necessary to retrieve the correct address after
7888 each encoding operation.
7891 It is important to realize that the ODR stream will not release this
7892 memory when you call <function>odr_reset()</function>: It will
7893 merely update its internal pointers to prepare for the encoding of a
7895 When the stream is released by the <function>odr_destroy()</function>
7896 function, the memory given to it by <function>odr_setbuf</function> will
7897 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
7898 parameter to <function>odr_setbuf()</function> was nonzero. The
7899 <literal>can_grow</literal> parameter, in other words, is a way of
7900 signaling who is to own the buffer, you or the ODR stream. If you never call
7901 <function>odr_setbuf()</function> on your encoding stream, which is
7902 typically the case, the buffer allocated by the stream will belong to
7903 the stream by default.
7906 When you wish to decode data, you should first call
7907 <function>odr_setbuf()</function>, to tell the decoding stream
7908 where to find the encoded data, and how long the buffer is
7909 (the <literal>can_grow</literal> parameter is ignored by a decoding
7910 stream). After this, you can call the function corresponding to the
7911 data you wish to decode (eg, <function>odr_integer()</function> odr
7912 <function>z_APDU()</function>).
7914 <example id="example.odr.encoding.and.decoding.functions">
7915 <title>Encoding and decoding functions</title>
7917 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
7919 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
7923 If the data is absent (or doesn't match the tag corresponding to
7924 the type), the return value will be either 0 or 1 depending on the
7925 <literal>optional</literal> flag. If <literal>optional</literal>
7926 is 0 and the data is absent, an error flag will be raised in the
7927 stream, and you'll need to call <function>odr_reset()</function> before
7928 you can use the stream again. If <literal>optional</literal> is
7929 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
7930 <literal>p</literal> will be set to the null value, and the function
7932 The <literal>name</literal> argument is used to pretty-print the
7933 tag in question. It may be set to <literal>NULL</literal> if
7934 pretty-printing is not desired.
7937 If the data value is found where it's expected, the pointer
7938 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
7939 will be set to point to the decoded type.
7940 The space for the type will be allocated and owned by the &odr;
7941 stream, and it will live until you call
7942 <function>odr_reset()</function> on the stream. You cannot use
7943 <function>free(2)</function> to release the memory.
7944 You can decode several data elements (by repeated calls to
7945 <function>odr_setbuf()</function> and your decoding function), and
7946 new memory will be allocated each time. When you do call
7947 <function>odr_reset()</function>, everything decoded since the
7948 last call to <function>odr_reset()</function> will be released.
7950 <example id="example.odr.encoding.of.integer">
7951 <title>Encoding and decoding of an integer</title>
7953 The use of the double indirection can be a little confusing at first
7954 (its purpose will become clear later on, hopefully),
7955 so an example is in order. We'll encode an integer value, and
7956 immediately decode it again using a different stream. A useless, but
7957 informative operation.
7959 <programlisting><![CDATA[
7960 void do_nothing_useful(Odr_int value)
7963 Odr_int *valp, *resvalp;
7967 /* allocate streams */
7968 if (!(encode = odr_createmem(ODR_ENCODE)))
7970 if (!(decode = odr_createmem(ODR_DECODE)))
7974 if (odr_integer(encode, &valp, 0, 0) == 0)
7976 printf("encoding went bad\n");
7979 bufferp = odr_getbuf(encode, &len, 0);
7980 printf("length of encoded data is %d\n", len);
7982 /* now let's decode the thing again */
7983 odr_setbuf(decode, bufferp, len, 0);
7984 if (odr_integer(decode, &resvalp, 0, 0) == 0)
7986 printf("decoding went bad\n");
7989 /* ODR_INT_PRINTF format for printf (such as %d) */
7990 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
7993 odr_destroy(encode);
7994 odr_destroy(decode);
7999 This looks like a lot of work, offhand. In practice, the &odr; streams
8000 will typically be allocated once, in the beginning of your program
8001 (or at the beginning of a new network session), and the encoding
8002 and decoding will only take place in a few, isolated places in your
8003 program, so the overhead is quite manageable.
8007 <sect2 id="odr.printing">
8008 <title>Printing</title>
8010 When an ODR stream is created of type <literal>ODR_PRINT</literal>
8011 the ODR module will print the contents of a PDU in a readable format.
8012 By default output is written to the <literal>stderr</literal> stream.
8013 This behavior can be changed, however, by calling the function
8015 odr_setprint(ODR o, FILE *file);
8017 before encoders or decoders are being invoked.
8018 It is also possible to direct the output to a buffer (of indeed
8019 another file), by using the more generic mechanism:
8021 void odr_set_stream(ODR o, void *handle,
8022 void (*stream_write)(ODR o, void *handle, int type,
8023 const char *buf, int len),
8024 void (*stream_close)(void *handle));
8026 Here the user provides an opaque handle and two handlers,
8027 <replaceable>stream_write</replaceable> for writing,
8028 and <replaceable>stream_close</replaceable> which is supposed
8029 to close/free resources associated with handle.
8030 The <replaceable>stream_close</replaceable> handler is optional and
8031 if NULL for the function is provided, it will not be invoked.
8032 The <replaceable>stream_write</replaceable> takes the ODR handle
8033 as parameter, the user defined handle, a type
8034 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8035 which indicates the type of contents is being written.
8038 Another utility useful for diagnostics (error handling) or as
8039 part of the printing facilities is:
8041 const char **odr_get_element_path(ODR o);
8043 which returns a list of current elements that ODR deals with at the
8044 moment. For the returned array, say <literal>ar</literal>,
8045 <literal>ar[0]</literal> is the top level element,
8046 <literal>ar[n]</literal> is the last. The last element has the
8047 property that <literal>ar[n+1] == NULL</literal>.
8049 <example id="example.odr.element.path.record">
8050 <title>Element Path for record</title>
8052 For a database record part of a PresentResponse the
8053 array returned by <function>odr_get_element</function>
8054 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8055 unnamed constructions.
8059 <sect2 id="odr.diagnostics">
8060 <title>Diagnostics</title>
8062 The encoding/decoding functions all return 0 when an error occurs.
8063 Until you call <function>odr_reset()</function>, you cannot use the
8064 stream again, and any function called will immediately return 0.
8067 To provide information to the programmer or administrator, the function
8070 void odr_perror(ODR o, char *message);
8073 is provided, which prints the <literal>message</literal> argument to
8074 <literal>stderr</literal> along with an error message from the stream.
8077 You can also use the function
8080 int odr_geterror(ODR o);
8083 to get the current error number from the screen. The number will be
8084 one of these constants:
8086 <table frame="top" id="odr.error.codes">
8087 <title>ODR Error codes</title>
8092 <entry>Description</entry>
8097 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8100 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8101 The standard diagnostic variable <literal>errno</literal> should be
8102 examined to determine the actual error.</entry>
8105 <entry>OSPACE</entry><entry>No more space for encoding.
8106 This will only occur when the user has explicitly provided a
8107 buffer for an encoding stream without allowing the system to
8108 allocate more space.</entry>
8111 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8112 required data element was missing during encoding or decoding.</entry>
8115 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8116 found during decoding.</entry>
8119 <entry>OOTHER</entry><entry>Other error. This is typically an
8120 indication of misuse of the &odr; system by the programmer, and also
8121 that the diagnostic system isn't as good as it should be, yet.</entry>
8127 The character string array
8133 can be indexed by the error code to obtain a human-readable
8134 representation of the problem.
8137 <sect2 id="odr.summary.and.synopsis">
8138 <title>Summary and Synopsis</title>
8140 #include <yaz/odr.h>
8142 ODR odr_createmem(int direction);
8144 void odr_destroy(ODR o);
8146 void odr_reset(ODR o);
8148 char *odr_getbuf(ODR o, int *len, int *size);
8150 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8152 void *odr_malloc(ODR o, int size);
8154 NMEM odr_extract_mem(ODR o);
8156 int odr_geterror(ODR o);
8158 void odr_perror(ODR o, const char *message);
8160 extern char *odr_errlist[];
8164 <sect1 id="odr.programming">
8165 <title>Programming with ODR</title>
8167 The API of &odr; is designed to reflect the structure of ASN.1, rather
8168 than BER itself. Future releases may be able to represent data in
8169 other external forms.
8173 There is an ASN.1 tutorial available at
8174 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8175 This site also has standards for ASN.1 (X.680) and BER (X.690)
8176 <ulink url="&url.asn.1.standards;">online</ulink>.
8180 The ODR interface is based loosely on that of the Sun Microsystems
8182 Specifically, each function which corresponds to an ASN.1 primitive
8183 type has a dual function. Depending on the settings of the ODR
8184 stream which is supplied as a parameter, the function may be used
8185 either to encode or decode data. The functions that can be built
8186 using these primitive functions, to represent more complex data types,
8187 share this quality. The result is that you only have to enter the
8188 definition for a type once - and you have the functionality of encoding,
8189 decoding (and pretty-printing) all in one unit.
8190 The resulting C source code is quite compact, and is a pretty
8191 straightforward representation of the source ASN.1 specification.
8194 In many cases, the model of the XDR functions works quite well in this
8196 In others, it is less elegant. Most of the hassle comes from the optional
8197 SEQUENCE members which don't exist in XDR.
8199 <sect2 id="odr.primitive.asn1.types">
8200 <title>The Primitive ASN.1 Types</title>
8202 ASN.1 defines a number of primitive types (many of which correspond
8203 roughly to primitive types in structured programming languages, such as C).
8205 <sect3 id="odr.integer">
8206 <title>INTEGER</title>
8208 The &odr; function for encoding or decoding (or printing) the ASN.1
8209 INTEGER type looks like this:
8212 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8215 The <literal>Odr_int</literal> is just a simple integer.
8218 This form is typical of the primitive &odr; functions. They are named
8219 after the type of data that they encode or decode. They take an &odr;
8220 stream, an indirect reference to the type in question, and an
8221 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8222 of ASN.1) as parameters. They all return an integer value of either one
8224 When you use the primitive functions to construct encoders for complex
8225 types of your own, you should follow this model as well. This
8226 ensures that your new types can be reused as elements in yet more
8230 The <literal>o</literal> parameter should obviously refer to a properly
8231 initialized &odr; stream of the right type (encoding/decoding/printing)
8232 for the operation that you wish to perform.
8235 When encoding or printing, the function first looks at
8236 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8237 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8238 the data element is absent. If the <literal>optional</literal> parameter
8239 is nonzero, the function will return one (signifying success) without
8240 any further processing. If the <literal>optional</literal> is zero, an
8241 internal error flag is set in the &odr; stream, and the function will
8242 return 0. No further operations can be carried out on the stream without
8243 a call to the function <function>odr_reset()</function>.
8246 If <literal>*p</literal> is not a null pointer, it is expected to
8247 point to an instance of the data type. The data will be subjected to
8248 the encoding rules, and the result will be placed in the buffer held
8249 by the &odr; stream.
8252 The other ASN.1 primitives have similar functions that operate in
8256 <sect3 id="odr.boolean">
8257 <title>BOOLEAN</title>
8259 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8262 <sect3 id="odr.real">
8268 <sect3 id="odr.null">
8271 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8274 In this case, the value of **p is not important. If <literal>*p</literal>
8275 is different from the null pointer, the null value is present, otherwise
8279 <sect3 id="odr.octet.string">
8280 <title>OCTET STRING</title>
8282 typedef struct odr_oct
8288 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8292 The <literal>buf</literal> field should point to the character array
8293 that holds the octetstring. The <literal>len</literal> field holds the
8295 The character array need not be null terminated.
8298 To make things a little easier, an alternative is given for string
8299 types that are not expected to contain embedded NULL characters (eg.
8303 int odr_cstring(ODR o, char **p, int optional, const char *name);
8306 Which encoded or decodes between OCTETSTRING representations and
8307 null-terminates C strings.
8310 Functions are provided for the derived string types, eg:
8313 int odr_visiblestring(ODR o, char **p, int optional,
8317 <sect3 id="odr.bit.string">
8318 <title>BIT STRING</title>
8320 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8324 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8325 holding relatively brief bit strings, eg. for options fields, etc.
8326 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8327 gives the maximum possible number of bits.
8330 A set of macros are provided for manipulating the
8331 <literal>Odr_bitmask</literal> type:
8334 void ODR_MASK_ZERO(Odr_bitmask *b);
8336 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8338 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8340 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8343 The functions are modeled after the manipulation functions that
8344 accompany the <literal>fd_set</literal> type used by the
8345 <function>select(2)</function> call.
8346 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8347 new bitmask, to initialize the bits to zero.
8350 <sect3 id="odr.object.identifier">
8351 <title>OBJECT IDENTIFIER</title>
8353 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8356 The C OID representation is simply an array of integers, terminated by
8357 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8358 the <literal>short</literal> type).
8359 We suggest that you use the OID database module (see
8360 <xref linkend="tools.oid.database"/>) to handle object identifiers
8361 in your application.
8365 <sect2 id="odr.tagging.primitive.types">
8366 <title>Tagging Primitive Types</title>
8368 The simplest way of tagging a type is to use the
8369 <function>odr_implicit_tag()</function> or
8370 <function>odr_explicit_tag()</function> macros:
8373 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8374 int optional, const char *name);
8376 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8377 int optional, const char *name);
8380 To create a type derived from the integer type by implicit tagging, you
8384 MyInt ::= [210] IMPLICIT INTEGER
8387 In the &odr; system, this would be written like:
8390 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8392 return odr_implicit_tag(o, odr_integer, p,
8393 ODR_CONTEXT, 210, optional, name);
8397 The function <function>myInt()</function> can then be used like any of
8398 the primitive functions provided by &odr;. Note that the behavior of
8399 <function>odr_explicit_tag()</function>
8400 and <function>odr_implicit_tag()</function> macros
8401 act exactly the same as the functions they are applied to - they
8402 respond to error conditions, etc, in the same manner - they
8403 simply have three extra parameters. The class parameter may
8404 take one of the values: <literal>ODR_CONTEXT</literal>,
8405 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8406 <literal>/ODR_APPLICATION</literal>.
8409 <sect2 id="odr.constructed.types">
8410 <title>Constructed Types</title>
8412 Constructed types are created by combining primitive types. The
8413 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8414 (although adding the rest of the container types should be simple
8415 enough, if the need arises).
8418 For implementing SEQUENCEs, the functions
8421 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8422 int odr_sequence_end(ODR o);
8428 The <function>odr_sequence_begin()</function> function should be
8429 called in the beginning of a function that implements a SEQUENCE type.
8430 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8431 you're implementing), and the <literal>size</literal> of the type
8432 (typically a C structure). On encoding, it returns 1 if
8433 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8434 parameter is ignored. On decoding, it returns 1 if the type is found in
8435 the data stream. <literal>size</literal> bytes of memory are allocated,
8436 and <literal>*p</literal> is set to point to this space.
8437 <function>odr_sequence_end()</function> is called at the end of the
8438 complex function. Assume that a type is defined like this:
8441 MySequence ::= SEQUENCE {
8443 boolval BOOLEAN OPTIONAL
8447 The corresponding &odr; encoder/decoder function and the associated data
8448 structures could be written like this:
8451 typedef struct MySequence
8457 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8459 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8460 return optional && odr_ok(o);
8462 odr_integer(o, &(*p)->intval, 0, "intval") &&
8463 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8464 odr_sequence_end(o);
8468 Note the 1 in the call to <function>odr_bool()</function>, to mark
8469 that the sequence member is optional.
8470 If either of the member types had been tagged, the macros
8471 <function>odr_implicit_tag()</function> or
8472 <function>odr_explicit_tag()</function>
8473 could have been used.
8474 The new function can be used exactly like the standard functions provided
8475 with &odr;. It will encode, decode or pretty-print a data value of the
8476 <literal>MySequence</literal> type. We like to name types with an
8477 initial capital, as done in ASN.1 definitions, and to name the
8478 corresponding function with the first character of the name in lower case.
8479 You could, of course, name your structures, types, and functions any way
8480 you please - as long as you're consistent, and your code is easily readable.
8481 <literal>odr_ok</literal> is just that - a predicate that returns the
8482 state of the stream. It is used to ensure that the behavior of the new
8483 type is compatible with the interface of the primitive types.
8486 <sect2 id="odr.tagging.constructed.types">
8487 <title>Tagging Constructed Types</title>
8490 See <xref linkend="odr.tagging.primitive.types"/> for information
8491 on how to tag the primitive types, as well as types that are
8495 <sect3 id="odr.implicit.tagging">
8496 <title>Implicit Tagging</title>
8498 Assume the type above had been defined as
8501 MySequence ::= [10] IMPLICIT SEQUENCE {
8503 boolval BOOLEAN OPTIONAL
8507 You would implement this in &odr; by calling the function
8510 int odr_implicit_settag(ODR o, int class, int tag);
8513 which overrides the tag of the type immediately following it. The
8514 macro <function>odr_implicit_tag()</function> works by calling
8515 <function>odr_implicit_settag()</function> immediately
8516 before calling the function pointer argument.
8517 Your type function could look like this:
8520 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8522 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8523 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8524 return optional && odr_ok(o);
8526 odr_integer(o, &(*p)->intval, 0, "intval") &&
8527 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8528 odr_sequence_end(o);
8532 The definition of the structure <literal>MySequence</literal> would be
8536 <sect3 id="odr.explicit.tagging">
8537 <title>Explicit Tagging</title>
8539 Explicit tagging of constructed types is a little more complicated,
8540 since you are in effect adding a level of construction to the data.
8543 Assume the definition:
8546 MySequence ::= [10] IMPLICIT SEQUENCE {
8548 boolval BOOLEAN OPTIONAL
8552 Since the new type has an extra level of construction, two new functions
8553 are needed to encapsulate the base type:
8556 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8559 int odr_constructed_end(ODR o);
8562 Assume that the IMPLICIT in the type definition above were replaced
8563 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8564 would be equivalent). The structure definition would look the same,
8565 but the function would look like this:
8568 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8570 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8571 return optional && odr_ok(o);
8572 if (o->direction == ODR_DECODE)
8573 *p = odr_malloc(o, sizeof(**p));
8574 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8576 *p = 0; /* this is almost certainly a protocol error */
8580 odr_integer(o, &(*p)->intval, 0, "intval") &&
8581 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8582 odr_sequence_end(o) &&
8583 odr_constructed_end(o);
8587 Notice that the interface here gets kind of nasty. The reason is
8588 simple: Explicitly tagged, constructed types are fairly rare in
8589 the protocols that we care about, so the
8590 esthetic annoyance (not to mention the dangers of a cluttered
8591 interface) is less than the time that would be required to develop a
8592 better interface. Nevertheless, it is far from satisfying, and it's a
8593 point that will be worked on in the future. One option for you would
8594 be to simply apply the <function>odr_explicit_tag()</function> macro to
8595 the first function, and not
8596 have to worry about <function>odr_constructed_*</function> yourself.
8597 Incidentally, as you might have guessed, the
8598 <function>odr_sequence_</function> functions are themselves
8599 implemented using the <function>/odr_constructed_</function> functions.
8603 <sect2 id="odr.sequence.of">
8604 <title>SEQUENCE OF</title>
8606 To handle sequences (arrays) of a specific type, the function
8609 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8610 void *p, int *num, const char *name);
8613 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8614 function of the type. <literal>p</literal> is a pointer to an array of
8615 pointers to your type. <literal>num</literal> is the number of elements
8622 MyArray ::= SEQUENCE OF INTEGER
8625 The C representation might be
8628 typedef struct MyArray
8635 And the function might look like
8638 int myArray(ODR o, MyArray **p, int optional, const char *name)
8640 if (o->direction == ODR_DECODE)
8641 *p = odr_malloc(o, sizeof(**p));
8642 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8643 &(*p)->num_elements, name))
8646 return optional && odr_ok(o);
8650 <sect2 id="odr.choice.types">
8651 <title>CHOICE Types</title>
8653 The choice type is used fairly often in some ASN.1 definitions, so
8654 some work has gone into streamlining its interface.
8657 CHOICE types are handled by the function:
8660 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8664 The <literal>arm</literal> array is used to describe each of the possible
8665 types that the CHOICE type may assume. Internally in your application,
8666 the CHOICE type is represented as a discriminated union. That is, a
8667 C union accompanied by an integer (or enum) identifying the active
8669 <literal>whichp</literal> is a pointer to the union discriminator.
8670 When encoding, it is examined to determine the current type.
8671 When decoding, it is set to reference the type that was found in
8675 The Odr_arm type is defined thus:
8678 typedef struct odr_arm
8689 The interpretation of the fields are:
8693 <term>tagmode</term>
8694 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8695 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8696 to mark no tagging.</para></listitem>
8700 <listitem><para>The value of the discriminator that corresponds to
8701 this CHOICE element. Typically, it will be a #defined constant, or
8702 an enum member.</para></listitem>
8706 <listitem><para>A pointer to a function that implements the type of
8707 the CHOICE member. It may be either a standard &odr; type or a type
8708 defined by yourself.</para></listitem>
8712 <listitem><para>Name of tag.</para></listitem>
8716 A handy way to prepare the array for use by the
8717 <function>odr_choice()</function> function is to
8718 define it as a static, initialized array in the beginning of your
8719 decoding/encoding function. Assume the type definition:
8722 MyChoice ::= CHOICE {
8724 tagged [99] IMPLICIT INTEGER,
8729 Your C type might look like
8732 typedef struct MyChoice
8749 And your function could look like this:
8752 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8754 static Odr_arm arm[] =
8756 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8757 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8759 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8763 if (o->direction == ODR_DECODE)
8764 *p = odr_malloc(o, sizeof(**p);
8766 return optional && odr_ok(o);
8768 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8771 return optional && odr_ok(o);
8775 In some cases (say, a non-optional choice which is a member of a
8776 sequence), you can "embed" the union and its discriminator in the
8777 structure belonging to the enclosing type, and you won't need to
8778 fiddle with memory allocation to create a separate structure to
8779 wrap the discriminator and union.
8782 The corresponding function is somewhat nicer in the Sun XDR interface.
8783 Most of the complexity of this interface comes from the possibility of
8784 declaring sequence elements (including CHOICEs) optional.
8787 The ASN.1 specifications naturally requires that each member of a
8788 CHOICE have a distinct tag, so they can be told apart on decoding.
8789 Sometimes it can be useful to define a CHOICE that has multiple types
8790 that share the same tag. You'll need some other mechanism, perhaps
8791 keyed to the context of the CHOICE type. In effect, we would like to
8792 introduce a level of context-sensitiveness to our ASN.1 specification.
8793 When encoding an internal representation, we have no problem, as long
8794 as each CHOICE member has a distinct discriminator value. For
8795 decoding, we need a way to tell the choice function to look for a
8796 specific arm of the table. The function
8799 void odr_choice_bias(ODR o, int what);
8802 provides this functionality. When called, it leaves a notice for the next
8803 call to <function>odr_choice()</function> to be called on the decoding
8804 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8805 a <literal>which</literal> field equal to <literal>what</literal>
8809 The most important application (perhaps the only one, really) is in
8810 the definition of application-specific EXTERNAL encoders/decoders
8811 which will automatically decode an ANY member given the direct or
8816 <sect1 id="odr.debugging">
8817 <title>Debugging</title>
8819 The protocol modules are suffering somewhat from a lack of diagnostic
8820 tools at the moment. Specifically ways to pretty-print PDUs that
8821 aren't recognized by the system. We'll include something to this end
8822 in a not-too-distant release. In the meantime, what we do when we get
8823 packages we don't understand is to compile the ODR module with
8824 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
8825 information as it processes data units. With this output and the
8826 protocol specification (Z39.50), it is generally fairly easy to see
8831 <chapter id="comstack">
8832 <title>The COMSTACK Module</title>
8833 <sect1 id="comstack.synopsis">
8834 <title>Synopsis (blocking mode)</title>
8835 <programlisting><![CDATA[
8838 int size = 0, length_incoming;
8839 char server_address_str[] = "localhost:9999";
8840 void *server_address_ip;
8843 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
8844 int protocol_package_length = strlen(protocol_package);
8846 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
8848 perror("cs_create"); /* use perror() here since we have no stack yet */
8852 server_address_ip = cs_straddr(stack, server_address_str);
8853 if (!server_address_ip) {
8854 fprintf(stderr, "cs_straddr: address could not be resolved\n");
8858 status = cs_connect(stack, server_address_ip);
8860 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
8864 status = cs_rcvconnect(stack);
8866 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
8870 status = cs_put(stack, protocol_package, protocol_package_length);
8872 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
8876 /* Now get a response */
8877 length_incoming = cs_get(stack, &buf, &size);
8878 if (!length_incoming) {
8879 fprintf(stderr, "Connection closed\n");
8881 } else if (length_incoming < 0) {
8882 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
8887 fwrite(buf, length_incoming, 1, stdout);
8898 <sect1 id="comstack.introduction">
8899 <title>Introduction</title>
8902 subsystem provides a transparent interface to different types of transport
8903 stacks for the exchange of BER-encoded data and HTTP packets.
8904 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
8905 experimental SSL stack are supported, but others may be added in time.
8906 The philosophy of the
8907 module is to provide a simple interface by hiding unused options and
8908 facilities of the underlying libraries. This is always done at the risk
8909 of losing generality, and it may prove that the interface will need
8914 There hasn't been interest in the XTImOSI stack for some years.
8915 Therefore, it is no longer supported.
8919 The interface is implemented in such a fashion that only the
8920 sub-layers constructed to the transport methods that you wish to
8921 use in your application are linked in.
8924 You will note that even though simplicity was a goal in the design,
8925 the interface is still orders of magnitudes more complex than the
8926 transport systems found in many other packages. One reason is that
8927 the interface needs to support the somewhat different requirements of
8928 the different lower-layer communications stacks; another important
8929 reason is that the interface seeks to provide a more or less
8930 industrial-strength approach to asynchronous event-handling.
8931 When no function is allowed to block, things get more complex -
8932 particularly on the server side.
8933 We urge you to have a look at the demonstration client and server
8934 provided with the package. They are meant to be easily readable and
8935 instructive, while still being at least moderately useful.
8938 <sect1 id="comstack.common">
8939 <title>Common Functions</title>
8940 <sect2 id="comstack.managing.endpoints">
8941 <title>Managing Endpoints</title>
8943 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
8946 Creates an instance of the protocol stack - a communications endpoint.
8947 The <literal>type</literal> parameter determines the mode
8948 of communication. At present the following values are supported:
8952 <term><literal>tcpip_type</literal></term>
8953 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
8957 <term><literal>ssl_type</literal></term>
8958 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
8959 is experimental and is not fully implemented. If
8960 HTTP is used, this effectively is HTTPS.
8964 <term><literal>unix_type</literal></term>
8965 <listitem><para>Unix socket (unix only). Local Transfer via
8966 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
8967 <manvolnum>7</manvolnum></citerefentry>.
8972 The <function>cs_create</function> function returns a null-pointer
8973 if a system error occurs.
8974 The <literal>blocking</literal> parameter should be one if
8975 you wish the association to operate in blocking mode, zero otherwise.
8976 The <literal>protocol</literal> field should be
8977 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
8978 Protocol <literal>PROTO_SR</literal> is no longer supported.
8981 void cs_close(COMSTACK handle);
8984 Closes the connection (as elegantly as the lower layers will permit),
8985 and releases the resources pointed to by the
8986 <literal>handle</literal>
8988 <literal>handle</literal>
8989 should not be referenced again after this call.
8993 We really need a soft disconnect, don't we?
8997 <sect2 id="comstack.data.exchange">
8998 <title>Data Exchange</title>
9000 int cs_put(COMSTACK handle, char *buf, int len);
9003 Sends <literal>buf</literal> down the wire.
9004 In blocking mode, this function will return only when a full buffer has
9005 been written, or an error has occurred. In nonblocking mode, it's
9006 possible that the function will be unable to send the full buffer
9007 at once, which will be indicated by a return value of 1.
9008 The function will keep track of the number of octets already written; you
9009 should call it repeatedly with the same values of <literal>buf</literal>
9010 and <literal>len</literal>, until the buffer has been transmitted.
9011 When a full buffer has been sent, the function will return 0 for
9012 success. -1 indicates an error condition (see below).
9015 int cs_get(COMSTACK handle, char **buf, int *size);
9018 Receives a PDU or HTTP Response from the peer. Returns the number of
9020 In nonblocking mode, it is possible that not all of the packet can be
9021 read at once. In this case, the function returns 1. To simplify the
9022 interface, the function is
9023 responsible for managing the size of the buffer. It will be reallocated
9024 if necessary to contain large packages, and will sometimes be moved
9025 around internally by the subsystem when partial packages are read. Before
9027 <function>cs_get</function>
9028 for the fist time, the buffer can be initialized to the null pointer,
9029 and the length should also be set to 0 - cs_get will perform a
9030 <function>malloc(2)</function>
9031 on the buffer for you. When a full buffer has been read, the size of
9032 the package is returned (which will always be greater than 1). -1
9033 indicates an error condition.
9036 See also the <function>cs_more()</function> function below.
9039 int cs_more(COMSTACK handle);
9042 The <function>cs_more()</function> function should be used in conjunction
9043 with <function>cs_get</function> and
9044 <function>select(2)</function>.
9045 The <function>cs_get()</function> function will sometimes
9046 (notably in the TCP/IP mode) read more than a single protocol package
9047 off the network. When this happens, the extra package is stored
9048 by the subsystem. After calling <function>cs_get()</function>, and before
9049 waiting for more input, You should always call
9050 <function>cs_more()</function>
9051 to check if there's a full protocol package already read. If
9052 <function>cs_more()</function>
9054 <function>cs_get()</function>
9055 can be used to immediately fetch the new package. For the
9057 subsystem, the function should always return 0, but if you want your
9058 stuff to be protocol independent, you should use it.
9062 The <function>cs_more()</function>
9063 function is required because the RFC1729-method
9064 does not provide a way of separating individual PDUs, short of
9065 partially decoding the BER. Some other implementations will carefully
9066 nibble at the packet by calling
9067 <function>read(2)</function>
9068 several times. This was felt to be too inefficient (or at least
9069 clumsy) - hence the call for this extra function.
9073 int cs_look(COMSTACK handle);
9076 This function is useful when you're operating in nonblocking
9078 <function>select(2)</function>
9079 tells you there's something happening on the line. It returns one of
9080 the following values:
9084 <term>CS_NONE</term>
9086 No event is pending. The data found on the line was not a
9091 <term>CS_CONNECT</term>
9093 A response to your connect request has been received. Call
9094 <function>cs_rcvconnect</function>
9095 to process the event and to finalize the connection establishment.
9099 <term>CS_DISCON</term>
9101 The other side has closed the connection (or maybe sent a disconnect
9102 request - but do we care? Maybe later). Call
9103 <function>cs_close</function> to close your end of the association
9108 <term>CS_LISTEN</term>
9110 A connect request has been received.
9111 Call <function>cs_listen</function> to process the event.
9115 <term>CS_DATA</term>
9117 There's data to be found on the line.
9118 Call <function>cs_get</function> to get it.
9124 You should be aware that even if
9125 <function>cs_look()</function>
9126 tells you that there's an event event pending, the corresponding
9127 function may still return and tell you there was nothing to be found.
9128 This means that only part of a package was available for reading. The
9129 same event will show up again, when more data has arrived.
9133 int cs_fileno(COMSTACK h);
9136 Returns the file descriptor of the association. Use this when
9137 file-level operations on the endpoint are required
9138 (<function>select(2)</function> operations, specifically).
9142 <sect1 id="comstack.client">
9143 <title>Client Side</title>
9145 int cs_connect(COMSTACK handle, void *address);
9148 Initiate a connection with the target at <literal>address</literal>
9149 (more on addresses below). The function will return 0 on success, and 1 if
9150 the operation does not complete immediately (this will only
9151 happen on a nonblocking endpoint). In this case, use
9152 <function>cs_rcvconnect</function> to complete the operation,
9153 when <function>select(2)</function> or <function>poll(2)</function>
9154 reports input pending on the association.
9157 int cs_rcvconnect(COMSTACK handle);
9160 Complete a connect operation initiated by <function>cs_connect()</function>.
9161 It will return 0 on success; 1 if the operation has not yet completed (in
9162 this case, call the function again later); -1 if an error has occurred.
9165 <sect1 id="comstack.server">
9166 <title>Server Side</title>
9168 To establish a server under the <application>inetd</application>
9172 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9176 The <literal>socket</literal> parameter is an established socket (when
9177 your application is invoked from <application>inetd</application>, the
9178 socket will typically be 0.
9179 The following parameters are identical to the ones for
9180 <function>cs_create</function>.
9183 int cs_bind(COMSTACK handle, void *address, int mode)
9186 Binds a local address to the endpoint. Read about addresses below. The
9187 <literal>mode</literal> parameter should be either
9188 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9191 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9194 Call this to process incoming events on an endpoint that has been
9195 bound in listening mode. It will return 0 to indicate that the connect
9196 request has been received, 1 to signal a partial reception, and -1 to
9197 indicate an error condition.
9200 COMSTACK cs_accept(COMSTACK handle);
9203 This finalizes the server-side association establishment, after
9204 cs_listen has completed successfully. It returns a new connection
9205 endpoint, which represents the new association. The application will
9206 typically wish to fork off a process to handle the association at this
9207 point, and continue listen for new connections on the old
9208 <literal>handle</literal>.
9211 You can use the call
9214 const char *cs_addrstr(COMSTACK);
9217 on an established connection to retrieve the host-name of the remote host.
9221 You may need to use this function with some care if your
9222 name server service is slow or unreliable
9226 <sect1 id="comstack.addresses">
9227 <title>Addresses</title>
9229 The low-level format of the addresses are different depending on the
9230 mode of communication you have chosen. A function is provided by each
9231 of the lower layers to map a user-friendly string-form address to the
9232 binary form required by the lower layers.
9235 void *cs_straddr(COMSTACK handle, const char *str);
9238 The format for TCP/IP and SSL addresses is:
9241 <host> [ ':' <portnum> ]
9244 The <literal>hostname</literal> can be either a domain name or an
9245 IP address. The port number, if omitted, defaults to 210.
9248 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9249 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9250 IPV4 binding as well (bindv6only=0),
9251 The special hostname <literal>@4</literal> binds to
9252 <literal>INADDR_ANY</literal> (IPV4 only listener).
9253 The special hostname <literal>@6</literal> binds to
9254 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9257 For UNIX sockets, the format of an address is the socket filename.
9260 When a connection has been established, you can use
9263 const char *cs_addrstr(COMSTACK h);
9266 to retrieve the host name of the peer system. The function returns
9267 a pointer to a static area, which is overwritten on the next call
9271 A fairly recent addition to the &comstack; module is the utility
9275 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9278 which is just a wrapper for <function>cs_create</function> and
9279 <function>cs_straddr</function>. The <parameter>str</parameter>
9280 is similar to that described for <function>cs_straddr</function>
9281 but with a prefix denoting the &comstack; type. Prefixes supported
9282 are <literal>tcp:</literal>, <literal>unix:</literal> and
9283 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9284 If no prefix is given, then TCP/IP is used.
9285 The <parameter>blocking</parameter> is passed to
9286 function <function>cs_create</function>. The third parameter
9287 <parameter>vp</parameter> is a pointer to &comstack; stack type
9289 Parameter <parameter>vp</parameter> is reserved for future use.
9290 Set it to <literal>NULL</literal>.
9293 <sect1 id="comstack.ssl">
9297 void *cs_get_ssl(COMSTACK cs);
9299 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9300 is not of type SSL, NULL is returned.
9304 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9306 Sets SSL context for comstack. The parameter is expected to be of type
9307 <literal>SSL_CTX *</literal>. This function should be called just
9308 after comstack has been created (before connect, bind, etc).
9309 This function returns 1 for success; 0 for failure.
9313 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9315 Sets SSL certificate for comstack as a PEM file. This function
9316 returns 1 for success; 0 for failure.
9320 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9322 This function returns the peer certificate. If successful,
9323 <literal>*buf</literal> and <literal>*len</literal> holds
9324 X509 buffer and length respectively. Buffer should be freed
9325 with <literal>xfree</literal>. This function returns 1 for success;
9329 <sect1 id="comstack.diagnostics">
9330 <title>Diagnostics</title>
9332 All functions return -1 if an error occurs. Typically, the functions
9333 will return 0 on success, but the data exchange functions
9334 (<function>cs_get</function>, <function>cs_put</function>,
9335 <function>cs_more</function>) follow special rules. Consult their
9339 The error code for the COMSTACK can be retrieved using C macro
9340 <function>cs_errno</function> which will return one
9341 of the error codes <literal>CSYSERR</literal>,
9342 <literal>CSOUTSTATE</literal>,
9343 <literal>CSNODATA</literal>, ...
9346 int cs_errno(COMSTACK handle);
9349 You can the textual representation of the error code
9350 by using <function>cs_errmsg</function> - which
9351 works like <function>strerror(3)</function>
9354 const char *cs_errmsg(int n);
9357 It is also possible to get straight to the textual represenataion
9358 without the error code by using
9359 <function>cs_strerror</function>.
9362 const char *cs_strerror(COMSTACK h);
9365 <sect1 id="comstack.summary">
9366 <title>Summary and Synopsis</title>
9368 #include <yaz/comstack.h>
9370 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9371 #include <yaz/unix.h> /* this is for UNIX socket support */
9373 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9375 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9377 COMSTACK cs_create_host(const char *str, int blocking,
9380 int cs_bind(COMSTACK handle, int mode);
9382 int cs_connect(COMSTACK handle, void *address);
9384 int cs_rcvconnect(COMSTACK handle);
9386 int cs_listen(COMSTACK handle);
9388 COMSTACK cs_accept(COMSTACK handle);
9390 int cs_put(COMSTACK handle, char *buf, int len);
9392 int cs_get(COMSTACK handle, char **buf, int *size);
9394 int cs_more(COMSTACK handle);
9396 void cs_close(COMSTACK handle);
9398 int cs_look(COMSTACK handle);
9400 void *cs_straddr(COMSTACK handle, const char *str);
9402 const char *cs_addrstr(COMSTACK h);
9407 <chapter id="future">
9408 <title>Future Directions</title>
9410 We have a new and better version of the front-end server on the drawing
9411 board. Resources and external commitments will govern when we'll be
9412 able to do something real with it. Features should include greater
9413 flexibility, greater support for access/resource control, and easy
9414 support for Explain (possibly with Zebra as an extra database engine).
9417 &yaz; is a BER toolkit and as such should support all protocols
9418 out there based on that. We'd like to see running ILL applications.
9419 It shouldn't be that hard. Another thing that would be interesting is
9420 LDAP. Maybe a generic framework for doing IR using both LDAP and
9421 Z39.50 transparently.
9424 The SOAP implementation is incomplete. In the future we hope
9425 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9426 The authors of libxml2 are already working on XML Schema / RelaxNG
9427 compilers so this may not be too hard.
9430 It would be neat to have a proper module mechanism for the Generic
9431 Frontend Server so that backend would be dynamically
9432 loaded (as shared objects / DLLs).
9435 Other than that, &yaz; generally moves in the directions which appear to
9436 make the most people happy (including ourselves, as prime users of the
9437 software). If there's something you'd like to see in here, then drop
9438 us a note and let's see what we can come up with.
9441 <reference id="reference">
9442 <title>Reference</title>
9443 <partintro id="reference-introduction">
9445 The material in this chapter is drawn directly from the individual
9451 <appendix id="list-oids">
9452 <title>List of Object Identifiers</title>
9454 These is a list of object identifiers that are built into YAZ.
9458 <appendix id="bib1-diagnostics">
9459 <title>Bib-1 diagnostics</title>
9461 List of Bib-1 diagnostics that are known to YAZ.
9465 <appendix id="sru-diagnostics">
9466 <title>SRU diagnostics</title>
9468 List of SRU diagnostics that are known to YAZ.
9472 <appendix id="license">
9473 <title>License</title>
9474 <sect1 id="license.indexdata">
9475 <title>Index Data Copyright</title>
9477 Copyright © ©right-year; Index Data.
9480 All rights reserved.
9483 Redistribution and use in source and binary forms, with or without
9484 modification, are permitted provided that the following conditions are met:
9489 Redistributions of source code must retain the above copyright
9490 notice, this list of conditions and the following disclaimer.
9495 Redistributions in binary form must reproduce the above copyright
9496 notice, this list of conditions and the following disclaimer in the
9497 documentation and/or other materials provided with the distribution.
9502 Neither the name of Index Data nor the names of its contributors
9503 may be used to endorse or promote products derived from this
9504 software without specific prior written permission.
9509 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9510 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9511 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9512 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9513 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9514 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9515 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9516 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9517 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9518 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9523 <appendix id="indexdata">
9524 <title>About Index Data</title>
9526 Index Data is a consulting and software-development enterprise that
9527 specializes in library and information management systems. Our
9528 interests and expertise span a broad range of related fields, and one
9529 of our primary, long-term objectives is the development of a powerful
9530 information management
9531 system with open network interfaces and hyper-media capabilities.
9533 We make this software available free of charge, on a fairly unrestrictive
9534 license; as a service to the networking community, and to further the
9535 development of quality software for open network communication.
9537 We'll be happy to answer questions about the software, and about ourselves
9543 <street>Amagerfælledvej 56</street>
9544 <postcode>2300 Copenhagen S</postcode>
9545 <country>Denmark</country>
9546 Email <email>info@indexdata.dk</email>
9550 The Hacker's Jargon File has the following to say about the
9552 prefix "YA" in the name of a software product.
9556 Yet Another. adj. 1. Of your own work: A
9557 humorous allusion often used in titles to acknowledge that the
9558 topic is not original, though the content is. As in "Yet Another
9559 AI Group" or "Yet Another Simulated Annealing Algorithm".
9561 others' work: Describes something of which there are already far
9566 <appendix id="credits">
9567 <title>Credits</title>
9569 This appendix lists individuals that have contributed in the development
9570 of &yaz;. Some have contributed with code, while others have provided bug
9571 fixes or suggestions. If we're missing somebody, of if you, for
9572 whatever reason, don't like to be listed here, let us know.
9582 Morten Bøgeskov
9603 Mads Bondo Dydensborg
9612 Morten Garkier Hendriksen
9669 Tom André Øverland
9675 <!-- Keep this comment at the end of the file
9678 nxml-child-indent: 1