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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.
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
1009 <literal>ZLIB_DIR</literal> to the zlib directory.
1012 Windows versions of libxslt, libxml2, zlib and iconv can be found
1013 <ulink url="&url.libxml2.download.win32;">
1014 Igor Zlatković' site</ulink>.
1018 YAZ is not using zlib but libxml2 is depending on it.
1024 <term><literal>HAVE_LIBXSLT</literal>,
1025 <literal>LIBXSLT_DIR</literal></term>
1028 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1029 with XSLT support. In this configuration, set
1030 <literal>LIBXSLT_DIR</literal> to the
1031 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1035 libxslt depends libxml2.
1041 <term><literal>HAVE_ICU</literal>,
1042 <literal>ICU_DIR</literal></term>
1045 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1046 with <ulink url="&url.icu;">ICU</ulink> support.
1047 In this configuration, set
1048 <literal>ICU_DIR</literal> to the
1049 <ulink url="&url.icu;">ICU</ulink> source directory.
1056 When satisfied with the settings in the makefile, type
1063 If the <filename>nmake</filename> command is not found on your system
1064 you probably haven't defined the environment variables required to
1065 use that tool. To fix that, find and run the batch file
1066 <filename>vcvars32.bat</filename>. You need to run it from within
1067 the command prompt or set the environment variables "globally";
1068 otherwise it doesn't work.
1072 If you wish to recompile &yaz; - for example if you modify
1073 settings in the <filename>makefile</filename> you can delete
1074 object files, etc by running.
1080 The following files are generated upon successful compilation:
1083 <term><filename>bin/yaz&soversion;.dll</filename> /
1084 <filename>bin/yaz&soversion;d.dll</filename></term>
1086 &yaz; Release/Debug DLL.
1090 <term><filename>lib/yaz&soversion;.lib</filename> /
1091 <filename>lib/yaz&soversion;d.lib</filename></term>
1093 Import library for <filename>yaz&soversion;.dll</filename> /
1094 <filename>yaz&soversion;d.dll</filename>.
1098 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1099 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1101 Release/Debug DLL for condition variable utilities (condvar.c).
1105 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1106 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1108 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1109 <filename>yaz_cond&soversion;d.dll</filename>.
1113 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1114 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1116 Release/Debug DLL for the ICU wrapper utility.
1117 Only build if HAVE_ICU is 1.
1121 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1122 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1124 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1125 <filename>yaz_icu&soversion;d.dll</filename>.
1129 <term><filename>bin/yaz-ztest.exe</filename></term>
1131 Z39.50 multi-threaded test/example server. It's a WIN32
1132 console application.
1136 <term><filename>bin/yaz-client.exe</filename></term>
1138 &yaz; Z39.50 client application. It's a WIN32 console application.
1139 See chapter <link linkend="yaz-client">YAZ client</link> for more
1144 <term><filename>bin/yaz-icu.exe</filename></term>
1145 <listitem><para>This program exposes the ICU wrapper library if that
1146 is enabled for YAZ. Only if ICU is available this program is
1151 <term><filename>bin/zoomsh.exe</filename></term>
1153 Simple console application implemented on top of the
1154 <link linkend="zoom">ZOOM</link> functions.
1155 The application is a command line shell that allows you to enter
1156 simple commands to perform ZOOM operations.
1160 <term><filename>bin/zoomtst1.exe</filename>,
1161 <filename>bin/zoomtst2.exe</filename>, ..</term>
1163 Several small applications that demonstrates the ZOOM API.
1170 <sect2 id="installation-linking-yaz-win32">
1171 <title>How to make apps using YAZ on WIN32</title>
1173 This section will go though the process of linking your WIN32
1174 applications with &yaz;.
1177 Some people are confused by the fact that we use the nmake
1178 tool to build &yaz;. They think they have to do that too - in order
1179 to make their WIN32 applications work with &yaz;. The good news is that
1180 you don't have to. You can use the integrated environment of
1181 Visual Studio if desired for your own application.
1184 When setting up a project or Makefile you have to set the following:
1187 <term>include path</term>
1189 Set it to the <filename>include</filename> directory of &yaz;.
1193 <term>import library <filename>yaz&soversion;.lib</filename></term>
1195 You must link with this library. It's located in the
1196 sub directory <filename>lib</filename> of &yaz;.
1197 If you want to link with the debug version of &yaz;, you must
1198 link against <filename>yaz&soversion;d.lib</filename> instead.
1202 <term>dynamic link library
1203 <filename>yaz&soversion;.dll</filename>
1206 This DLL must be in your execution path when you invoke
1207 your application. Specifically, you should distribute this
1208 DLL with your application.
1217 ### Still to document:
1218 ZOOM_connection_errcode(c)
1219 ZOOM_connection_errmsg(c)
1220 ZOOM_connection_addinfo(c)
1221 ZOOM_connection_addinfo(c)
1222 ZOOM_connection_diagset(c);
1223 ZOOM_connection_save_apdu_wrbuf
1224 ZOOM_diag_str(error)
1225 ZOOM_resultset_record_immediate(s, pos)
1226 ZOOM_resultset_cache_reset(r)
1227 ZOOM_options_set_callback(opt, function, handle)
1228 ZOOM_options_create_with_parent2(parent1, parent2)
1229 ZOOM_options_getl(opt, name, len)
1230 ZOOM_options_setl(opt, name, value, len)
1231 ZOOM_options_get_bool(opt, name, defa)
1232 ZOOM_options_get_int(opt, name, defa)
1233 ZOOM_options_set_int(opt, name, value)
1238 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1239 an initiative started by Mike Taylor (Mike is from the UK, which
1240 explains the peculiar name of the model). The goal of &zoom; is to
1241 provide a common Z39.50 client API not bound to a particular
1242 programming language or toolkit.
1245 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1246 You can make SRU ZOOM connections by specifying scheme
1247 <literal>http://</literal> for the hostname for a connection.
1248 The dialect of SRU used is specified by the value of the
1249 connection's <literal>sru</literal> option, which may be SRU over
1250 HTTP GET (<literal>get</literal>),
1251 SRU over HTTP POST (<literal>post</literal>), (SRU over
1252 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1253 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1254 Using the facility for embedding options in target strings, a
1255 connection can be forced to use SRU rather the SRW (the default) by
1256 prefixing the target string with <literal>sru=get,</literal>, like this:
1257 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1260 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1261 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1262 HTTP based protocols.
1265 The lack of a simple Z39.50 client API for &yaz; has become more
1266 and more apparent over time. So when the first &zoom; specification
1268 an implementation for &yaz; was quickly developed. For the first time, it is
1269 now as easy (or easier!) to develop clients than servers with &yaz;. This
1270 chapter describes the &zoom; C binding. Before going further, please
1271 reconsider whether C is the right programming language for the job.
1272 There are other language bindings available for &yaz;, and still
1274 are in active development. See the
1275 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1279 In order to fully understand this chapter you should read and
1280 try the example programs <literal>zoomtst1.c</literal>,
1281 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1285 The C language misses features found in object oriented languages
1286 such as C++, Java, etc. For example, you'll have to manually,
1287 destroy all objects you create, even though you may think of them as
1288 temporary. Most objects has a <literal>_create</literal> - and a
1289 <literal>_destroy</literal> variant.
1290 All objects are in fact pointers to internal stuff, but you don't see
1291 that because of typedefs. All destroy methods should gracefully ignore a
1292 <literal>NULL</literal> pointer.
1295 In each of the sections below you'll find a sub section called
1296 protocol behavior, that describes how the API maps to the Z39.50
1299 <sect1 id="zoom-connections">
1300 <title>Connections</title>
1301 <para>The Connection object is a session with a target.
1304 #include <yaz/zoom.h>
1306 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1308 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1310 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1312 void ZOOM_connection_destroy(ZOOM_connection c);
1315 Connection objects are created with either function
1316 <function>ZOOM_connection_new</function> or
1317 <function>ZOOM_connection_create</function>.
1318 The former creates and automatically attempts to establish a network
1319 connection with the target. The latter doesn't establish
1320 a connection immediately, thus allowing you to specify options
1321 before establishing network connection using the function
1322 <function>ZOOM_connection_connect</function>.
1323 If the port number, <literal>portnum</literal>, is zero, the
1324 <literal>host</literal> is consulted for a port specification.
1325 If no port is given, 210 is used. A colon denotes the beginning of
1326 a port number in the host string. If the host string includes a
1327 slash, the following part specifies a database for the connection.
1330 You can prefix the host with a scheme followed by colon. The
1331 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1332 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1333 but can overridded to use SRU/post, SRW and the Solr protocol.
1336 You can prefix the scheme-qualified host-string with one or more
1338 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1339 sequences, each of which represents an option to be set into the
1340 connection structure <emphasis>before</emphasis> the
1341 protocol-level connection is forged and the initialization
1342 handshake takes place. This facility can be used to provide
1343 authentication credentials, as in host-strings such as:
1344 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1347 Connection objects should be destroyed using the function
1348 <function>ZOOM_connection_destroy</function>.
1351 void ZOOM_connection_option_set(ZOOM_connection c,
1352 const char *key, const char *val);
1354 void ZOOM_connection_option_setl(ZOOM_connection c,
1356 const char *val, int len);
1358 const char *ZOOM_connection_option_get(ZOOM_connection c,
1360 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1365 The functions <function>ZOOM_connection_option_set</function> and
1366 <function>ZOOM_connection_option_setl</function> allows you to
1367 set an option given by <parameter>key</parameter> to the value
1368 <parameter>value</parameter> for the connection.
1369 For <function>ZOOM_connection_option_set</function>, the
1370 value is assumed to be a 0-terminated string. Function
1371 <function>ZOOM_connection_option_setl</function> specifies a
1372 value of a certain size (len).
1375 Functions <function>ZOOM_connection_option_get</function> and
1376 <function>ZOOM_connection_option_getl</function> returns
1377 the value for an option given by <parameter>key</parameter>.
1379 <table id="zoom-connection-options" frame="top">
1380 <title>ZOOM Connection Options</title>
1382 <colspec colwidth="4*" colname="name"></colspec>
1383 <colspec colwidth="7*" colname="description"></colspec>
1384 <colspec colwidth="3*" colname="default"></colspec>
1387 <entry>Option</entry>
1388 <entry>Description</entry>
1389 <entry>Default</entry>
1394 implementationName</entry><entry>Name of Your client
1395 </entry><entry>none</entry></row>
1397 user</entry><entry>Authentication user name
1398 </entry><entry>none</entry></row>
1400 group</entry><entry>Authentication group name
1401 </entry><entry>none</entry></row>
1403 password</entry><entry>Authentication password.
1404 </entry><entry>none</entry></row>
1406 authenticationMode</entry><entry>How authentication is encoded.
1407 </entry><entry>basic</entry></row>
1409 host</entry><entry>Target host. This setting is "read-only".
1410 It's automatically set internally when connecting to a target.
1411 </entry><entry>none</entry></row>
1413 proxy</entry><entry>Proxy host. If set, the logical host
1414 is encoded in the otherInfo area of the Z39.50 Init PDU
1415 with OID 1.2.840.10003.10.1000.81.1.
1416 </entry><entry>none</entry></row>
1418 clientIP</entry><entry>Client IP. If set, is
1419 encoded in the otherInfo area of a Z39.50 PDU with OID
1420 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1421 of a client. Is used of ZOOM is used in a gateway of some sort.
1422 </entry><entry>none</entry></row>
1424 async</entry><entry>If true (1) the connection operates in
1425 asynchronous operation which means that all calls are non-blocking
1427 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1428 </entry><entry>0</entry></row>
1430 maximumRecordSize</entry><entry> Maximum size of single record.
1431 </entry><entry>1 MB</entry></row>
1433 preferredMessageSize</entry><entry> Maximum size of multiple records.
1434 </entry><entry>1 MB</entry></row>
1436 lang</entry><entry> Language for negotiation.
1437 </entry><entry>none</entry></row>
1439 charset</entry><entry> Character set for negotiation.
1440 </entry><entry>none</entry></row>
1442 serverImplementationId</entry><entry>
1443 Implementation ID of server. (The old targetImplementationId
1444 option is also supported for the benefit of old applications.)
1445 </entry><entry>none</entry></row>
1447 targetImplementationName</entry><entry>
1448 Implementation Name of server. (The old
1449 targetImplementationName option is also supported for the
1450 benefit of old applications.)
1451 </entry><entry>none</entry></row>
1453 serverImplementationVersion</entry><entry>
1454 Implementation Version of server. (the old
1455 targetImplementationVersion option is also supported for the
1456 benefit of old applications.)
1457 </entry><entry>none</entry></row>
1459 databaseName</entry><entry>One or more database names
1460 separated by character plus (<literal>+</literal>), which to
1461 be used by subsequent search requests on this Connection.
1462 </entry><entry>Default</entry></row>
1464 piggyback</entry><entry>True (1) if piggyback should be
1465 used in searches; false (0) if not.
1466 </entry><entry>1</entry></row>
1468 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1469 value, then target will return all records using small element set name
1470 </entry><entry>0</entry></row>
1472 largeSetLowerBound</entry><entry>If hits is greater than this
1473 value, the target will return no records.
1474 </entry><entry>1</entry></row>
1476 mediumSetPresentNumber</entry><entry>This value represents
1477 the number of records to be returned as part of a search when when
1478 hits is less than or equal to large set lower bound and if hits
1479 is greater than small set upper bound.
1480 </entry><entry>0</entry></row>
1482 smallSetElementSetName</entry><entry>
1483 The element set name to be used for small result sets.
1484 </entry><entry>none</entry></row>
1486 mediumSetElementSetName</entry><entry>
1487 The element set name to be for medium-sized result sets.
1488 </entry><entry>none</entry></row>
1490 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1491 After a successful Init, these options may be interrogated to
1492 discover whether the server claims to support the specified
1494 </entry><entry>none</entry></row>
1496 <entry>sru</entry><entry>
1497 SRU/Solr transport type. Must be either <literal>soap</literal>,
1498 <literal>get</literal>, <literal>post</literal>, or
1499 <literal>solr</literal>.
1500 </entry><entry>soap</entry></row>
1502 sru_version</entry><entry>
1503 SRU/SRW version. Should be <literal>1.1</literal>, or
1504 <literal>1.2</literal>. This is , prior to connect, the version
1505 to offer (highest version). And following connect (in fact
1506 first operation), holds the negotiated version with the server
1507 (same or lower version).
1508 </entry><entry>1.2</entry></row>
1509 <row id="zoom.facets.option"><entry>
1510 facets</entry><entry>
1511 Requested or recommend facets may be given before a search is sent.
1512 The value of this setting is described in <xref linkend="facets"/>
1513 For inspection of the facets returned, refer to the functions
1514 described in <xref linkend="zoom.facets"/>.
1515 </entry><entry>none</entry></row>
1517 apdulog</entry><entry>
1518 If set to a true value such as "1", a log of low-level
1519 protocol packets is emitted on standard error stream. This
1520 can be very useful for debugging.
1521 </entry><entry>0</entry></row>
1523 saveAPDU</entry><entry>
1524 If set to a true value such as "1", a log of low-level
1525 protocol packets is saved. The log can be retrieved by reading
1526 option APDU. Setting saveAPDU always has the side effect of
1527 resetting the currently saved log. This setting is
1528 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1529 It is only recognized in
1530 <function>ZOOM_connection_option_set</function>.
1531 </entry><entry>0</entry></row>
1534 Returns the log of protocol packets. Will be empty if logging
1535 is not enabled (see saveAPDU above). This setting is
1536 <emphasis>read-only</emphasis>. It is only recognized if used
1537 in call to <function>ZOOM_connection_option_get</function> or
1538 <function>ZOOM_connection_option_getl</function>.
1539 </entry><entry></entry></row>
1541 memcached</entry><entry>
1542 If given and non-empty,
1543 <ulink url="&url.libmemcached;">libMemcached</ulink>
1544 will be configured for the connection.
1545 This option is inspected by ZOOM when a connection is established.
1546 If the <literal>memcached</literal> option is given
1547 and YAZ is compiled without libMemcached support, an internal
1548 diagnostic (10018) will be thrown.
1549 libMemcached support is available for YAZ 5.0.13 or later. If this
1550 option is supplied for an earlier version of YAZ, it is
1551 <emphasis>ignored</emphasis>.
1552 The value of this option is a string passed verbatim to
1553 the <function>memcached</function> function part of libMemcached.
1555 <ulink url="http://manned.org/memcached.3">memcached(3)</ulink>.
1556 Earlier versions of libMemcached
1557 do not offer this function. In this case only the option
1558 <literal>--server=</literal><replaceable>host</replaceable> may
1559 be given (YAZ emulates that part of libMemcached).
1560 </entry><entry>none</entry></row>
1562 redis</entry><entry>
1563 If given and non-empty,
1564 a <ulink url="&url.redis;">redis</ulink> context will be created
1566 This option is inspected by ZOOM when a connection is established.
1567 If the <literal>redis</literal> option is given
1568 and YAZ is compiled without redis support, an internal
1569 diagnostic (10018) will be thrown.
1570 redis support is available for YAZ 5.2.0 or later. If this
1571 option is supplied for an earlier version of YAZ, it is
1572 <emphasis>ignored</emphasis>.
1573 The value of this option is a set options, similar to that
1574 of the memcached function. At this stage only --server=host[:port]
1575 is supported. Later versions of YAZ might honor expiry for various
1576 items and other things that tune the redis usage.
1577 </entry><entry>none</entry></row>
1582 If either option <literal>lang</literal> or <literal>charset</literal>
1584 <ulink url="&url.z39.50.charneg;">
1585 Character Set and Language Negotiation</ulink> is in effect.
1588 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1589 const char **addinfo);
1590 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1591 const char **addinfo, const char **dset);
1594 Function <function>ZOOM_connection_error</function> checks for
1595 errors for the last operation(s) performed. The function returns
1596 zero if no errors occurred; non-zero otherwise indicating the error.
1597 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1598 holds messages for the error and additional-info if passed as
1599 non-<literal>NULL</literal>. Function
1600 <function>ZOOM_connection_error_x</function> is an extended version
1601 of <function>ZOOM_connection_error</function> that is capable of
1602 returning name of diagnostic set in <parameter>dset</parameter>.
1604 <sect2 id="zoom-connection-z39.50">
1605 <title>Z39.50 Protocol behavior</title>
1607 The calls <function>ZOOM_connection_new</function> and
1608 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1609 connection and sends an Initialize Request to the target if
1610 possible. In addition, the calls waits for an Initialize Response
1611 from the target and the result is inspected (OK or rejected).
1614 If <literal>proxy</literal> is set then the client will establish
1615 a TCP/IP connection with the peer as specified by the
1616 <literal>proxy</literal> host and the hostname as part of the
1617 connect calls will be set as part of the Initialize Request.
1618 The proxy server will then "forward" the PDU's transparently
1619 to the target behind the proxy.
1622 For the authentication parameters, if option <literal>user</literal>
1623 is set and both options <literal>group</literal> and
1624 <literal>pass</literal> are unset, then Open style
1625 authentication is used (Version 2/3) in which case the username
1626 is usually followed by a slash, then by a password.
1627 If either <literal>group</literal>
1628 or <literal>pass</literal> is set then idPass authentication
1629 (Version 3 only) is used. If none of the options are set, no
1630 authentication parameters are set as part of the Initialize Request
1634 When option <literal>async</literal> is 1, it really means that
1635 all network operations are postponed (and queued) until the
1636 function <literal>ZOOM_event</literal> is invoked. When doing so
1637 it doesn't make sense to check for errors after
1638 <literal>ZOOM_connection_new</literal> is called since that
1639 operation "connecting - and init" is still incomplete and the
1640 API cannot tell the outcome (yet).
1643 <sect2 id="zoom.sru.init.behavior">
1644 <title>SRU/Solr Protocol behavior</title>
1646 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1647 Inititialize Request, so the connection phase merely establishes a
1648 TCP/IP connection with the HTTP server.
1650 <para>Most of the ZOOM connection options do not
1651 affect SRU/Solr and they are ignored. However, future versions
1652 of &yaz; might honor <literal>implementationName</literal> and
1653 put that as part of User-Agent header for HTTP requests.
1656 The <literal>charset</literal> is used in the Content-Type header
1660 Setting <literal>authentcationMode</literal> specifies how
1661 authentication parameters are encoded for HTTP. The default is
1662 "<literal>basic</literal>" where <literal>user</literal> and
1663 <literal>password</literal> are encoded by using HTTP basic
1667 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1668 user and password are encoded in the URL by parameters
1669 <literal>x-username</literal> and <literal>x-password</literal> as
1670 given by the SRU standard.
1674 <sect1 id="zoom.query">
1675 <title>Queries</title>
1677 Query objects represents queries.
1680 ZOOM_query ZOOM_query_create(void);
1682 void ZOOM_query_destroy(ZOOM_query q);
1684 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1686 int ZOOM_query_cql(ZOOM_query s, const char *str);
1688 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1690 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1691 const char *criteria);
1694 Create query objects using <function>ZOOM_query_create</function>
1695 and destroy them by calling <function>ZOOM_query_destroy</function>.
1696 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1697 notation by using the
1698 function <function>ZOOM_query_prefix</function>.
1699 The <function>ZOOM_query_cql</function> specifies a CQL
1700 query to be sent to the server/target.
1701 More query types will be added in future versions of &yaz;, such as
1702 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1703 etc. In addition to a search, a sort criteria may be set. Function
1704 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1705 it takes sort criteria using the same string notation as
1706 yaz-client's <link linkend="sortspec">sort command</link>.
1708 <para id="zoom.query.sortby2">
1709 <function>ZOOM_query_sortby2</function> is similar to
1710 <function>ZOOM_query_sortby</function> but allows a strategy for
1711 sorting. The reason for the strategy parameter is that some
1712 protocols offers multiple ways of performing sorting.
1713 For example, Z39.50 has the standard sort, which is performed after
1714 search on an existing result set.
1715 It's also possible to use CQL in Z39.50 as the query type and use
1716 CQL's SORTBY keyword. Finally, Index Data's
1717 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1719 <table id="zoom-sort-strategy" frame="top">
1720 <title>ZOOM sort strategy</title>
1722 <colspec colwidth="2*" colname="name"/>
1723 <colspec colwidth="5*" colname="description"/>
1727 <entry>Description</entry>
1732 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1735 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1738 <entry>cql</entry><entry>CQL SORTBY</entry>
1741 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1744 <entry>solr</entry><entry>Solr sort</entry>
1747 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1748 solr for Solr protocol</entry>
1754 <sect1 id="zoom.resultsets"><title>Result sets</title>
1756 The result set object is a container for records returned from
1760 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1762 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1764 void ZOOM_resultset_destroy(ZOOM_resultset r);
1767 Function <function>ZOOM_connection_search</function> creates
1768 a result set given a connection and query.
1769 Destroy a result set by calling
1770 <function>ZOOM_resultset_destroy</function>.
1771 Simple clients may using PQF only may use function
1772 <function>ZOOM_connection_search_pqf</function> in which case
1773 creating query objects is not necessary.
1776 void ZOOM_resultset_option_set(ZOOM_resultset r,
1777 const char *key, const char *val);
1779 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1781 size_t ZOOM_resultset_size(ZOOM_resultset r);
1784 Functions <function>ZOOM_resultset_options_set</function> and
1785 <function>ZOOM_resultset_get</function> sets and gets an option
1786 for a result set similar to <function>ZOOM_connection_option_get</function>
1787 and <function>ZOOM_connection_option_set</function>.
1790 The number of hits also called result-count is returned by
1791 function <function>ZOOM_resultset_size</function>.
1793 <table id="zoom.resultset.options"
1794 frame="top"><title>ZOOM Result set Options</title>
1796 <colspec colwidth="4*" colname="name"></colspec>
1797 <colspec colwidth="7*" colname="description"></colspec>
1798 <colspec colwidth="2*" colname="default"></colspec>
1801 <entry>Option</entry>
1802 <entry>Description</entry>
1803 <entry>Default</entry>
1808 start</entry><entry>Offset of first record to be
1809 retrieved from target. First record has offset 0 unlike the
1810 protocol specifications where first record has position 1.
1811 This option affects ZOOM_resultset_search and
1812 ZOOM_resultset_search_pqf and must be set before any of
1813 these functions are invoked. If a range of
1814 records must be fetched manually after search,
1815 function ZOOM_resultset_records should be used.
1816 </entry><entry>0</entry></row>
1818 count</entry><entry>Number of records to be retrieved.
1819 This option affects ZOOM_resultset_search and
1820 ZOOM_resultset_search_pqf and must be set before any of
1821 these functions are invoked.
1822 </entry><entry>0</entry></row>
1824 presentChunk</entry><entry>The number of records to be
1825 requested from the server in each chunk (present request). The
1826 value 0 means to request all the records in a single chunk.
1827 (The old <literal>step</literal>
1828 option is also supported for the benefit of old applications.)
1829 </entry><entry>0</entry></row>
1831 elementSetName</entry><entry>Element-Set name of records.
1832 Most targets should honor element set name <literal>B</literal>
1833 and <literal>F</literal> for brief and full respectively.
1834 </entry><entry>none</entry></row>
1836 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1837 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1838 </entry><entry>none</entry></row>
1840 schema</entry><entry>Schema for retrieval, such as
1841 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1842 </entry><entry>none</entry></row>
1844 setname</entry><entry>Name of Result Set (Result Set ID).
1845 If this option isn't set, the ZOOM module will automatically
1846 allocate a result set name.
1847 </entry><entry>default</entry></row>
1849 rpnCharset</entry><entry>Character set for RPN terms.
1850 If this is set, ZOOM C will assume that the ZOOM application is
1851 running UTF-8. Terms in RPN queries are then converted to the
1852 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1853 of RPN terms and no conversion is performed.
1854 </entry><entry>none</entry></row>
1859 For servers that support Search Info report, the following
1860 options may be read using <function>ZOOM_resultset_get</function>.
1861 This detailed information is read after a successful search has
1865 This information is a list of of items, where each item is
1866 information about a term or subquery. All items in the list
1868 <literal>SearchResult.</literal><replaceable>no</replaceable>
1869 where no presents the item number (0=first, 1=second).
1870 Read <literal>searchresult.size</literal> to determine the
1873 <table id="zoom.search.info.report.options"
1874 frame="top"><title>Search Info Report Options</title>
1876 <colspec colwidth="4*" colname="name"></colspec>
1877 <colspec colwidth="7*" colname="description"></colspec>
1880 <entry>Option</entry>
1881 <entry>Description</entry>
1886 <entry>searchresult.size</entry>
1888 number of search result entries. This option is-nonexistant
1889 if no entries are returned by the server.
1893 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1894 <entry>sub query ID</entry>
1897 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1898 <entry>result count for item (number of hits)</entry>
1901 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1902 <entry>subquery term</entry>
1906 searchresult.<replaceable>no</replaceable>.interpretation.term
1908 <entry>interpretation term</entry>
1912 searchresult.<replaceable>no</replaceable>.recommendation.term
1914 <entry>recommendation term</entry>
1919 <sect2 id="zoom.z3950.resultset.sort">
1920 <title>Z39.50 Result-set Sort</title>
1922 void ZOOM_resultset_sort(ZOOM_resultset r,
1923 const char *sort_type, const char *sort_spec);
1925 int ZOOM_resultset_sort1(ZOOM_resultset r,
1926 const char *sort_type, const char *sort_spec);
1929 <function>ZOOM_resultset_sort</function> and
1930 <function>ZOOM_resultset_sort1</function> both sort an existing
1931 result-set. The sort_type parameter is not use. Set it to "yaz".
1932 The sort_spec is same notation as ZOOM_query_sortby and identical
1933 to that offered by yaz-client's
1934 <link linkend="sortspec">sort command</link>.
1937 These functions only work for Z39.50. Use the more generic utility
1938 <link linkend="zoom.query.sortby2">
1939 <function>ZOOM_query_sortby2</function></link>
1940 for other protocols (and even Z39.50).
1943 <sect2 id="zoom.z3950.resultset.behavior">
1944 <title>Z39.50 Protocol behavior</title>
1946 The creation of a result set involves at least a SearchRequest
1947 - SearchResponse protocol handshake. Following that, if a sort
1948 criteria was specified as part of the query, a SortRequest -
1949 SortResponse handshake takes place. Note that it is necessary to
1950 perform sorting before any retrieval takes place, so no records will
1951 be returned from the target as part of the SearchResponse because these
1952 would be unsorted. Hence, piggyback is disabled when sort criteria
1953 are set. Following Search - and a possible sort - Retrieval takes
1954 place - as one or more Present Requests/Response pairs being
1958 The API allows for two different modes for retrieval. A high level
1959 mode which is somewhat more powerful and a low level one.
1960 The low level is enabled when searching on a Connection object
1961 for which the settings
1962 <literal>smallSetUpperBound</literal>,
1963 <literal>mediumSetPresentNumber</literal> and
1964 <literal>largeSetLowerBound</literal> are set. The low level mode
1965 thus allows you to precisely set how records are returned as part
1966 of a search response as offered by the Z39.50 protocol.
1967 Since the client may be retrieving records as part of the
1968 search response, this mode doesn't work well if sorting is used.
1971 The high-level mode allows you to fetch a range of records from
1972 the result set with a given start offset. When you use this mode
1973 the client will automatically use piggyback if that is possible
1974 with the target and perform one or more present requests as needed.
1975 Even if the target returns fewer records as part of a present response
1976 because of a record size limit, etc. the client will repeat sending
1977 present requests. As an example, if option <literal>start</literal>
1978 is 0 (default) and <literal>count</literal> is 4, and
1979 <literal>piggyback</literal> is 1 (default) and no sorting criteria
1980 is specified, then the client will attempt to retrieve the 4
1981 records as part the search response (using piggyback). On the other
1982 hand, if either <literal>start</literal> is positive or if
1983 a sorting criteria is set, or if <literal>piggyback</literal>
1984 is 0, then the client will not perform piggyback but send Present
1988 If either of the options <literal>mediumSetElementSetName</literal> and
1989 <literal>smallSetElementSetName</literal> are unset, the value
1990 of option <literal>elementSetName</literal> is used for piggyback
1991 searches. This means that for the high-level mode you only have
1992 to specify one elementSetName option rather than three.
1995 <sect2 id="zoom.sru.resultset.behavior">
1996 <title>SRU Protocol behavior</title>
1998 Current version of &yaz; does not take advantage of a result set id
1999 returned by the SRU server. Future versions might do, however.
2000 Since, the ZOOM driver does not save result set IDs any
2001 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2002 with same query but, possibly, different offsets.
2005 Option <literal>schema</literal> specifies SRU schema
2006 for retrieval. However, options <literal>elementSetName</literal> and
2007 <literal>preferredRecordSyntax</literal> are ignored.
2010 Options <literal>start</literal> and <literal>count</literal>
2011 are supported by SRU.
2012 The remaining options
2013 <literal>piggyback</literal>,
2014 <literal>smallSetUpperBound</literal>,
2015 <literal>largeSetLowerBound</literal>,
2016 <literal>mediumSetPresentNumber</literal>,
2017 <literal>mediumSetElementSetName</literal>,
2018 <literal>smallSetElementSetName</literal> are
2022 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2023 If PQF is used, however, the PQF query is transferred anyway
2024 using non-standard element <literal>pQuery</literal> in
2025 SRU SearchRetrieveRequest.
2028 Solr queries has to be done in Solr query format.
2031 Unfortunately, SRU or Solr does not define a database setting. Hence,
2032 <literal>databaseName</literal> is unsupported and ignored.
2033 However, the path part in host parameter for functions
2034 <function>ZOOM_connecton_new</function> and
2035 <function>ZOOM_connection_connect</function> acts as a
2036 database (at least for the &yaz; SRU server).
2040 <sect1 id="zoom.records">
2041 <title>Records</title>
2043 A record object is a retrieval record on the client side -
2044 created from result sets.
2047 void ZOOM_resultset_records(ZOOM_resultset r,
2049 size_t start, size_t count);
2050 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2052 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2055 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2056 const char **addinfo, const char **diagset);
2058 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2060 void ZOOM_record_destroy(ZOOM_record rec);
2063 References to temporary records are returned by functions
2064 <function>ZOOM_resultset_records</function> or
2065 <function>ZOOM_resultset_record</function>.
2068 If a persistent reference to a record is desired
2069 <function>ZOOM_record_clone</function> should be used.
2070 It returns a record reference that should be destroyed
2071 by a call to <function>ZOOM_record_destroy</function>.
2074 A single record is returned by function
2075 <function>ZOOM_resultset_record</function> that takes a
2076 position as argument. First record has position zero.
2077 If no record could be obtained <literal>NULL</literal> is returned.
2080 Error information for a record can be checked with
2081 <function>ZOOM_record_error</function> which returns non-zero
2082 (error code) if record is in error, called <emphasis>Surrogate
2083 Diagnostics</emphasis> in Z39.50.
2086 Function <function>ZOOM_resultset_records</function> retrieves
2087 a number of records from a result set. Parameter <literal>start</literal>
2088 and <literal>count</literal> specifies the range of records to
2089 be returned. Upon completion array
2090 <literal>recs[0], ..recs[count-1]</literal>
2091 holds record objects for the records. The array of records
2092 <literal>recs</literal> should be allocated prior the call
2093 <function>ZOOM_resultset_records</function>. Note that for those
2094 records that couldn't be retrieved from the target
2095 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2097 <para id="zoom.record.get">
2098 In order to extract information about a single record,
2099 <function>ZOOM_record_get</function> is provided. The
2100 function returns a pointer to certain record information. The
2101 nature (type) of the pointer depends on the parameter,
2102 <parameter>type</parameter>.
2105 The <parameter>type</parameter> is a string of the format:
2108 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>]
2111 where <replaceable>format</replaceable> specifies the format of the
2112 returned record, <replaceable>from</replaceable>
2113 specifies the character set of the record in its original form
2114 (as returned by the server), <replaceable>to</replaceable> specifies
2115 the output (returned)
2116 character set encoding.
2117 If <replaceable>to</replaceable> is omitted UTF-8 is assumed.
2118 If charset is not given, then no character set conversion takes place.
2121 <para>OPAC records may be returned in a different
2122 set from the bibliographic MARC record. If this is this the case,
2123 <replaceable>opacfrom</replaceable> should be set to the character set
2124 of the OPAC record part.
2128 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2132 The format argument controls whether record data should be XML
2133 pretty-printed (post process operation).
2134 It is enabled only if format value <replaceable>v</replaceable> is
2135 <literal>1</literal> and the record content is XML well-formed.
2138 In addition, for certain types, the length
2139 <literal>len</literal> passed will be set to the size in bytes of
2140 the returned information.
2143 The following are the supported values for <replaceable>form</replaceable>.
2145 <varlistentry><term><literal>database</literal></term>
2146 <listitem><para>Database of record is returned
2147 as a C null-terminated string. Return type
2148 <literal>const char *</literal>.
2151 <varlistentry><term><literal>syntax</literal></term>
2152 <listitem><para>The transfer syntax of the record is returned
2153 as a C null-terminated string containing the symbolic name of
2154 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2156 <literal>const char *</literal>.
2159 <varlistentry><term><literal>schema</literal></term>
2160 <listitem><para>The schema of the record is returned
2161 as a C null-terminated string. Return type is
2162 <literal>const char *</literal>.
2165 <varlistentry><term><literal>render</literal></term>
2166 <listitem><para>The record is returned in a display friendly
2167 format. Upon completion buffer is returned
2168 (type <literal>const char *</literal>) and length is stored in
2169 <literal>*len</literal>.
2172 <varlistentry><term><literal>raw</literal></term>
2173 <listitem><para>The record is returned in the internal
2174 YAZ specific format. For GRS-1, Explain, and others, the
2175 raw data is returned as type
2176 <literal>Z_External *</literal> which is just the type for
2177 the member <literal>retrievalRecord</literal> in
2178 type <literal>NamePlusRecord</literal>.
2179 For SUTRS and octet aligned record (including all MARCs) the
2180 octet buffer is returned and the length of the buffer.
2183 <varlistentry><term><literal>xml</literal></term>
2184 <listitem><para>The record is returned in XML if possible.
2185 SRU, Solr and Z39.50 records with transfer syntax XML are
2186 returned verbatim. MARC records are returned in
2187 <ulink url="&url.marcxml;">
2190 (converted from ISO2709 to MARCXML by YAZ).
2191 OPAC records are also converted to XML and the
2192 bibliographic record is converted to MARCXML (when possible).
2193 GRS-1 records are not supported for this form.
2194 Upon completion, the XML buffer is returned
2195 (type <literal>const char *</literal>) and length is stored in
2196 <literal>*len</literal>.
2199 <varlistentry><term><literal>opac</literal></term>
2200 <listitem><para>OPAC information for record is returned in XML
2201 if an OPAC record is present at the position given. If no
2202 OPAC record is present, a NULL pointer is returned.
2205 <varlistentry><term><literal>txml</literal></term>
2206 <listitem><para>The record is returned in TurboMARC if possible.
2207 SRU and Z39.50 records with transfer syntax XML are
2208 returned verbatim. MARC records are returned in
2209 <link linkend="tools.turbomarc">
2212 (converted from ISO2709 to TurboMARC by YAZ).
2213 Upon completion, the XML buffer is returned
2214 (type <literal>const char *</literal>) and length is stored in
2215 <literal>*len</literal>.
2218 <varlistentry><term><literal>json</literal></term>
2219 <listitem><para>Like xml, but MARC records are converted to
2220 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2228 <ulink url="&url.marc21;">MARC21</ulink>
2230 <ulink url="&url.marc8;">MARC-8</ulink>
2231 character set encoding.
2232 An application that wishes to display in Latin-1 would use
2234 render; charset=marc8,iso-8859-1
2237 <sect2 id="zoom.z3950.record.behavior">
2238 <title>Z39.50 Protocol behavior</title>
2240 The functions <function>ZOOM_resultset_record</function> and
2241 <function>ZOOM_resultset_records</function> inspects the client-side
2242 record cache. Records not found in cache are fetched using
2244 The functions may block (and perform network I/O) - even though option
2245 <literal>async</literal> is 1, because they return records objects.
2246 (and there's no way to return records objects without retrieving them!).
2249 There is a trick, however, in the usage of function
2250 <function>ZOOM_resultset_records</function> that allows for
2251 delayed retrieval (and makes it non-blocking). By using
2252 a null pointer for <parameter>recs</parameter> you're indicating
2253 you're not interested in getting records objects
2254 <emphasis>now</emphasis>.
2257 <sect2 id="zoom.sru.record.behavior">
2258 <title>SRU/Solr Protocol behavior</title>
2260 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2261 as if they where Z39.50 records with transfer syntax XML and
2262 no element set name or database name.
2266 <sect1 id="zoom.facets"><title>Facets</title>
2268 Facet operations is not part of the official ZOOM specification, but
2269 is an Index Data extension for YAZ-based Z39.50 targets,
2270 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2272 Facets may be requestd by the
2273 <link linkend="zoom.facets.option">facets</link> option before a
2275 For inspection of the returned facets, the following functions are
2279 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2281 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2282 const char *facet_name);
2284 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2287 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2289 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2291 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2293 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2294 size_t idx, int *freq);
2297 References to temporary structures are returned by all functions.
2298 They are only valid as long the Result set is valid.
2299 <function>ZOOM_resultset_get_facet_field</function> or
2300 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2301 <function>ZOOM_resultset_facets</function>.
2302 <function>ZOOM_facet_field_name</function>.
2303 <function>ZOOM_facet_field_get_term</function>.
2305 <para id="zoom.resultset.get_facet_field">
2306 A single Facet field is returned by function
2307 <function>ZOOM_resultset_get_facet_field</function> or
2308 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2309 a result set and facet name or positive index respectively. First
2310 facet has position zero. If no facet could be obtained (invalid name
2311 or index out of bounds) <literal>NULL</literal> is returned.
2313 <para id="zoom.resultset.facets">
2314 An array of facets field can be returned by
2315 <function>ZOOM_resultset_facets</function>. The length of the array is
2316 given by <function>ZOOM_resultset_facets_size</function>. The array is
2317 zero-based and last entry will be at
2318 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2320 <para id="zoom.resultset.facets_names">
2321 It is possible to interate over facets by name, by calling
2322 <function>ZOOM_resultset_facets_names</function>.
2323 This will return an const array of char * where each string can be used
2324 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2327 Function <function>ZOOM_facet_field_name</function> gets the request
2328 facet name from a returned facet field.
2331 Function <function>ZOOM_facet_field_get_term</function> returns the
2332 idx'th term and term count for a facet field.
2333 Idx must between 0 and
2334 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2335 returned reference will be <literal>NULL</literal>. On a valid idx, the
2336 value of the freq reference will be the term count.
2337 The <literal>freq</literal> parameter must be valid pointer to integer.
2340 <sect1 id="zoom.scan"><title>Scan</title>
2342 This section describes an interface for Scan. Scan is not an
2343 official part of the ZOOM model yet. The result of a scan operation
2344 is the <literal>ZOOM_scanset</literal> which is a set of terms
2345 returned by a target.
2349 The Scan interface is supported for both Z39.50, SRU and Solr.
2353 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2354 const char *startpqf);
2356 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2359 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2361 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2362 size_t *occ, size_t *len);
2364 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2365 size_t *occ, size_t *len);
2367 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2369 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2372 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2376 The scan set is created by function
2377 <function>ZOOM_connection_scan</function> which performs a scan
2378 operation on the connection using the specified
2379 <parameter>startpqf</parameter>.
2380 If the operation was successful, the size of the scan set can be
2381 retrieved by a call to <function>ZOOM_scanset_size</function>.
2382 Like result sets, the items are numbered 0,..size-1.
2383 To obtain information about a particular scan term, call function
2384 <function>ZOOM_scanset_term</function>. This function takes
2385 a scan set offset <literal>pos</literal> and returns a pointer
2386 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2388 If present, the <literal>occ</literal> and <literal>len</literal>
2389 are set to the number of occurrences and the length
2390 of the actual term respectively.
2391 <function>ZOOM_scanset_display_term</function> is similar to
2392 <function>ZOOM_scanset_term</function> except that it returns
2393 the <emphasis>display term</emphasis> rather than the raw term.
2394 In a few cases, the term is different from display term. Always
2395 use the display term for display and the raw term for subsequent
2396 scan operations (to get more terms, next scan result, etc).
2399 A scan set may be freed by a call to function
2400 <function>ZOOM_scanset_destroy</function>.
2401 Functions <function>ZOOM_scanset_option_get</function> and
2402 <function>ZOOM_scanset_option_set</function> retrieves and sets
2403 an option respectively.
2406 The <parameter>startpqf</parameter> is a subset of PQF, namely
2407 the Attributes+Term part. Multiple <literal>@attr</literal> can
2408 be used. For example to scan in title (complete) phrases:
2410 @attr 1=4 @attr 6=2 "science o"
2414 The <function>ZOOM_connecton_scan1</function> is a newer and
2415 more generic alternative to <function>ZOOM_connection_scan</function>
2416 which allows to use both CQL and PQF for Scan.
2418 <table frame="top" id="zoom.scanset.options">
2419 <title>ZOOM Scan Set Options</title>
2421 <colspec colwidth="4*" colname="name"></colspec>
2422 <colspec colwidth="7*" colname="description"></colspec>
2423 <colspec colwidth="2*" colname="default"></colspec>
2426 <entry>Option</entry>
2427 <entry>Description</entry>
2428 <entry>Default</entry>
2433 number</entry><entry>Number of Scan Terms requested in next scan.
2434 After scan it holds the actual number of terms returned.
2435 </entry><entry>20</entry></row>
2437 position</entry><entry>Preferred Position of term in response
2438 in next scan; actual position after completion of scan.
2439 </entry><entry>1</entry></row>
2441 stepSize</entry><entry>Step Size
2442 </entry><entry>0</entry></row>
2444 scanStatus</entry><entry>An integer indicating the Scan Status
2446 </entry><entry>0</entry></row>
2448 rpnCharset</entry><entry>Character set for RPN terms.
2449 If this is set, ZOOM C will assume that the ZOOM application is
2450 running UTF-8. Terms in RPN queries are then converted to the
2451 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2452 of RPN terms and no conversion is performed.
2453 </entry><entry>none</entry></row>
2458 <sect1 id="zoom.extendedservices">
2459 <title>Extended Services</title>
2461 ZOOM offers an interface to a subset of the Z39.50 extended services
2462 as well as a few privately defined ones:
2467 Z39.50 Item Order (ILL).
2468 See <xref linkend="zoom.item.order"/>.
2473 Record Update. This allows a client to insert, modify or delete
2475 See <xref linkend="zoom.record.update"/>.
2480 Database Create. This a non-standard feature. Allows a client
2481 to create a database.
2482 See <xref linkend="zoom.database.create"/>.
2487 Database Drop. This a non-standard feature. Allows a client
2488 to delete/drop a database.
2489 See <xref linkend="zoom.database.drop"/>.
2494 Commit operation. This a non-standard feature. Allows a client
2495 to commit operations.
2496 See <xref linkend="zoom.commit"/>.
2499 <!-- all the ILL PDU options should go here too -->
2502 To create an extended service operation a <literal>ZOOM_package</literal>
2503 must be created. The operation is a five step operation. The
2504 package is created, package is configured by means of options,
2505 the package is send, result is inspected (by means of options),
2506 the package is destroyed.
2509 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2510 ZOOM_options options);
2512 const char *ZOOM_package_option_get(ZOOM_package p,
2514 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2516 void ZOOM_package_send(ZOOM_package p, const char *type);
2518 void ZOOM_package_destroy(ZOOM_package p);
2521 The <function>ZOOM_connection_package</function> creates a
2522 package for the connection given using the options specified.
2525 Functions <function>ZOOM_package_option_get</function> and
2526 <function>ZOOM_package_option_set</function> gets and sets
2530 <function>ZOOM_package_send</function> sends
2531 the package the via connection specified in
2532 <function>ZOOM_connection_package</function>.
2533 The <parameter>type</parameter> specifies the actual extended service
2534 package type to be sent.
2536 <table frame="top" id="zoom.extendedservices.options">
2537 <title>Extended Service Common Options</title>
2539 <colspec colwidth="4*" colname="name"></colspec>
2540 <colspec colwidth="7*" colname="description"></colspec>
2541 <colspec colwidth="3*" colname="default"></colspec>
2544 <entry>Option</entry>
2545 <entry>Description</entry>
2546 <entry>Default</entry>
2551 <entry>package-name</entry>
2552 <entry>Extended Service Request package name. Must be specified
2553 as part of a request</entry>
2557 <entry>user-id</entry>
2558 <entry>User ID of Extended Service Package. Is a request option</entry>
2562 <entry>function</entry>
2564 Function of package - one of <literal>create</literal>,
2565 <literal>delete</literal>, <literal>modify</literal>. Is
2568 <entry><literal>create</literal></entry>
2571 <entry>waitAction</entry>
2573 Wait action for package. Possible values:
2574 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2575 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2577 <entry><literal>waitIfPossible</literal></entry>
2580 <entry>targetReference</entry>
2582 Target Reference. This is part of the response as returned
2583 by the server. Read it after a successful operation.
2585 <entry><literal>none</literal></entry>
2590 <sect2 id="zoom.item.order">
2591 <title>Item Order</title>
2593 For Item Order, type must be set to <literal>itemorder</literal> in
2594 <function>ZOOM_package_send</function>.
2597 <table frame="top" id="zoom.item.order.options">
2598 <title>Item Order Options</title>
2600 <colspec colwidth="4*" colname="name"></colspec>
2601 <colspec colwidth="7*" colname="description"></colspec>
2602 <colspec colwidth="3*" colname="default"></colspec>
2605 <entry>Option</entry>
2606 <entry>Description</entry>
2607 <entry>Default</entry>
2612 <entry>contact-name</entry>
2613 <entry>ILL contact name</entry>
2617 <entry>contact-phone</entry>
2618 <entry>ILL contact phone</entry>
2622 <entry>contact-email</entry>
2623 <entry>ILL contact email</entry>
2627 <entry>itemorder-item</entry>
2628 <entry>Position for item (record) requested. An integer</entry>
2635 <sect2 id="zoom.record.update">
2636 <title>Record Update</title>
2638 For Record Update, type must be set to <literal>update</literal> in
2639 <function>ZOOM_package_send</function>.
2641 <table frame="top" id="zoom.record.update.options">
2642 <title>Record Update Options</title>
2644 <colspec colwidth="4*" colname="name"></colspec>
2645 <colspec colwidth="7*" colname="description"></colspec>
2646 <colspec colwidth="3*" colname="default"></colspec>
2649 <entry>Option</entry>
2650 <entry>Description</entry>
2651 <entry>Default</entry>
2656 <entry>action</entry>
2658 The update action. One of
2659 <literal>specialUpdate</literal>,
2660 <literal>recordInsert</literal>,
2661 <literal>recordReplace</literal>,
2662 <literal>recordDelete</literal>,
2663 <literal>elementUpdate</literal>.
2665 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2668 <entry>recordIdOpaque</entry>
2669 <entry>Opaque Record ID</entry>
2673 <entry>recordIdNumber</entry>
2674 <entry>Record ID number</entry>
2678 <entry>record</entry>
2679 <entry>The record itself</entry>
2683 <entry>recordOpaque</entry>
2684 <entry>Specifies an opaque record which is
2685 encoded as an ASN.1 ANY type with the OID as tiven by option
2686 <literal>syntax</literal> (see below).
2687 Option <literal>recordOpaque</literal> is an alternative
2688 to record - and <literal>record</literal> option (above) is
2689 ignored if recordOpaque is set. This option is only available in
2690 YAZ 3.0.35 and later and is meant to facilitate Updates with
2696 <entry>syntax</entry>
2697 <entry>The record syntax (transfer syntax). Is a string that
2698 is a known record syntax.
2700 <entry>no syntax</entry>
2703 <entry>databaseName</entry>
2704 <entry>Database from connection object</entry>
2705 <entry>Default</entry>
2708 <entry>correlationInfo.note</entry>
2709 <entry>Correlation Info Note (string)</entry>
2713 <entry>correlationInfo.id</entry>
2714 <entry>Correlation Info ID (integer)</entry>
2718 <entry>elementSetName</entry>
2719 <entry>Element Set for Record</entry>
2723 <entry>updateVersion</entry>
2724 <entry>Record Update version which holds one of the values
2725 1, 2 or 3. Each version has a distinct OID:
2727 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2729 (second version) and
2730 1.2.840.10003.9.5.1.1
2731 (<ulink url="&url.z39.50.extupdate3;">third and
2732 newest version</ulink>).
2742 <sect2 id="zoom.database.create"><title>Database Create</title>
2744 For Database Create, type must be set to <literal>create</literal> in
2745 <function>ZOOM_package_send</function>.
2748 <table frame="top" id="zoom.database.create.options">
2749 <title>Database Create Options</title>
2751 <colspec colwidth="4*" colname="name"></colspec>
2752 <colspec colwidth="7*" colname="description"></colspec>
2753 <colspec colwidth="3*" colname="default"></colspec>
2756 <entry>Option</entry>
2757 <entry>Description</entry>
2758 <entry>Default</entry>
2763 <entry>databaseName</entry>
2764 <entry>Database from connection object</entry>
2765 <entry>Default</entry>
2771 <sect2 id="zoom.database.drop">
2772 <title>Database Drop</title>
2774 For Database Drop, type must be set to <literal>drop</literal> in
2775 <function>ZOOM_package_send</function>.
2777 <table frame="top" id="zoom.database.drop.options">
2778 <title>Database Drop Options</title>
2780 <colspec colwidth="4*" colname="name"></colspec>
2781 <colspec colwidth="7*" colname="description"></colspec>
2782 <colspec colwidth="3*" colname="default"></colspec>
2785 <entry>Option</entry>
2786 <entry>Description</entry>
2787 <entry>Default</entry>
2792 <entry>databaseName</entry>
2793 <entry>Database from connection object</entry>
2794 <entry>Default</entry>
2800 <sect2 id="zoom.commit">
2801 <title>Commit Operation</title>
2803 For Commit, type must be set to <literal>commit</literal> in
2804 <function>ZOOM_package_send</function>.
2807 <sect2 id="zoom.extended.services.behavior">
2808 <title>Protocol behavior</title>
2810 All the extended services are Z39.50-only.
2814 The database create, drop and commit services are privately defined
2816 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2822 <sect1 id="zoom.options">
2823 <title>Options</title>
2825 Most &zoom; objects provide a way to specify options to change behavior.
2826 From an implementation point of view a set of options is just like
2827 an associative array / hash.
2830 ZOOM_options ZOOM_options_create(void);
2832 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
2834 void ZOOM_options_destroy(ZOOM_options opt);
2837 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
2839 void ZOOM_options_set(ZOOM_options opt, const char *name,
2843 typedef const char *(*ZOOM_options_callback)
2844 (void *handle, const char *name);
2846 ZOOM_options_callback
2847 ZOOM_options_set_callback(ZOOM_options opt,
2848 ZOOM_options_callback c,
2852 <sect1 id="zoom.queryconversions">
2853 <title>Query conversions</title>
2855 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
2856 ZOOM_connection conn);
2858 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
2860 int *ccl_error, const char **error_string,
2864 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
2865 client-side, into RPN which may be passed to the server.
2866 This is useful for server's that don't themselves
2867 support CQL, for which <function>ZOOM_query_cql</function> is useless.
2868 `conn' is used only as a place to stash diagnostics if compilation
2869 fails; if this information is not needed, a null pointer may be used.
2870 The CQL conversion is driven by option <literal>cqlfile</literal> from
2871 connection conn. This specifies a conversion file (eg pqf.properties)
2872 which <emphasis>must</emphasis> be present.
2875 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
2876 client-side, into RPN which may be passed to the server.
2877 The conversion is driven by the specification given by
2878 <literal>config</literal>. Upon completion 0 is returned on success; -1
2879 is returned on on failure. Om failure <literal>error_string</literal> and
2880 <literal>error_pos</literal> holds error message and position of
2881 first error in original CCL string.
2884 <sect1 id="zoom.events"><title>Events</title>
2886 If you're developing non-blocking applications, you have to deal
2890 int ZOOM_event(int no, ZOOM_connection *cs);
2893 The <function>ZOOM_event</function> executes pending events for
2894 a number of connections. Supply the number of connections in
2895 <literal>no</literal> and an array of connections in
2896 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
2897 A pending event could be a sending a search, receiving a response,
2899 When an event has occurred for one of the connections, this function
2900 returns a positive integer <literal>n</literal> denoting that an event
2901 occurred for connection <literal>cs[n-1]</literal>.
2902 When no events are pending for the connections, a value of zero is
2904 To ensure that all outstanding requests are performed call this function
2905 repeatedly until zero is returned.
2908 If <function>ZOOM_event</function> returns and returns non-zero, the
2909 last event that occurred can be expected.
2912 int ZOOM_connection_last_event(ZOOM_connection cs);
2915 <function>ZOOM_connection_last_event</function> returns an event type
2916 (integer) for the last event.
2919 <table frame="top" id="zoom.event.ids">
2920 <title>ZOOM Event IDs</title>
2922 <colspec colwidth="4*" colname="name"></colspec>
2923 <colspec colwidth="7*" colname="description"></colspec>
2926 <entry>Event</entry>
2927 <entry>Description</entry>
2932 <entry>ZOOM_EVENT_NONE</entry>
2933 <entry>No event has occurred</entry>
2936 <entry>ZOOM_EVENT_CONNECT</entry>
2937 <entry>TCP/IP connect has initiated</entry>
2940 <entry>ZOOM_EVENT_SEND_DATA</entry>
2941 <entry>Data has been transmitted (sending)</entry>
2944 <entry>ZOOM_EVENT_RECV_DATA</entry>
2945 <entry>Data has been received)</entry>
2948 <entry>ZOOM_EVENT_TIMEOUT</entry>
2949 <entry>Timeout</entry>
2952 <entry>ZOOM_EVENT_UNKNOWN</entry>
2953 <entry>Unknown event</entry>
2956 <entry>ZOOM_EVENT_SEND_APDU</entry>
2957 <entry>An APDU has been transmitted (sending)</entry>
2960 <entry>ZOOM_EVENT_RECV_APDU</entry>
2961 <entry>An APDU has been received</entry>
2964 <entry>ZOOM_EVENT_RECV_RECORD</entry>
2965 <entry>A result-set record has been received</entry>
2968 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
2969 <entry>A search result been received</entry>
2976 <chapter id="server">
2977 <title>Generic server</title>
2978 <sect1 id="server.introduction"><title>Introduction</title>
2980 If you aren't into documentation, a good way to learn how the
2981 back end interface works is to look at the <filename>backend.h</filename>
2982 file. Then, look at the small dummy-server in
2983 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
2984 file also makes a good reference, once you've chewed your way through
2985 the prose of this file.
2988 If you have a database system that you would like to make available by
2989 means of Z39.50 or SRU, &yaz; basically offers your two options. You
2990 can use the APIs provided by the &asn;, &odr;, and &comstack;
2992 create and decode PDUs, and exchange them with a client.
2993 Using this low-level interface gives you access to all fields and
2994 options of the protocol, and you can construct your server as close
2995 to your existing database as you like.
2996 It is also a fairly involved process, requiring
2997 you to set up an event-handling mechanism, protocol state machine,
2998 etc. To simplify server implementation, we have implemented a compact
2999 and simple, but reasonably full-functioned server-frontend that will
3000 handle most of the protocol mechanics, while leaving you to
3001 concentrate on your database interface.
3005 The backend interface was designed in anticipation of a specific
3006 integration task, while still attempting to achieve some degree of
3007 generality. We realize fully that there are points where the
3008 interface can be improved significantly. If you have specific
3009 functions or parameters that you think could be useful, send us a
3010 mail (or better, sign on to the mailing list referred to in the
3011 top-level README file). We will try to fit good suggestions into future
3012 releases, to the extent that it can be done without requiring
3013 too many structural changes in existing applications.
3018 The &yaz; server does not support XCQL.
3022 <sect1 id="server.frontend">
3023 <title>The Database Frontend</title>
3025 We refer to this software as a generic database frontend. Your
3026 database system is the <emphasis>backend database</emphasis>, and the
3027 interface between the two is called the <emphasis>backend API</emphasis>.
3028 The backend API consists of a small number of function handlers and
3029 structure definitions. You are required to provide the
3030 <function>main()</function> routine for the server (which can be
3031 quite simple), as well as a set of handlers to match each of the
3033 The interface functions that you write can use any mechanism you like
3034 to communicate with your database system: You might link the whole
3035 thing together with your database application and access it by
3036 function calls; you might use IPC to talk to a database server
3037 somewhere; or you might link with third-party software that handles
3038 the communication for you (like a commercial database client library).
3039 At any rate, the handlers will perform the tasks of:
3052 Scanning the database index (optional - if you wish to implement SCAN).
3055 Extended Services (optional).
3058 Result-Set Delete (optional).
3061 Result-Set Sort (optional).
3064 Return Explain for SRU (optional).
3068 (more functions will be added in time to support as much of
3069 Z39.50-1995 as possible).
3072 <sect1 id="server.backend">
3073 <title>The Backend API</title>
3075 The header file that you need to use the interface are in the
3076 <filename>include/yaz</filename> directory. It's called
3077 <filename>backend.h</filename>. It will include other files from
3078 the <filename>include/yaz</filename> directory, so you'll
3079 probably want to use the -I option of your compiler to tell it
3080 where to find the files. When you run
3081 <literal>make</literal> in the top-level &yaz; directory,
3082 everything you need to create your server is to link with the
3083 <filename>lib/libyaz.la</filename> library.
3086 <sect1 id="server.main">
3087 <title>Your main() Routine</title>
3089 As mentioned, your <function>main()</function> routine can be quite brief.
3090 If you want to initialize global parameters, or read global configuration
3091 tables, this is the place to do it. At the end of the routine, you should
3095 int statserv_main(int argc, char **argv,
3096 bend_initresult *(*bend_init)(bend_initrequest *r),
3097 void (*bend_close)(void *handle));
3100 The third and fourth arguments are pointers to handlers. Handler
3101 <function>bend_init</function> is called whenever the server receives
3102 an Initialize Request, so it serves as a Z39.50 session initializer. The
3103 <function>bend_close</function> handler is called when the session is
3107 <function>statserv_main</function> will establish listening sockets
3108 according to the parameters given. When connection requests are received,
3109 the event handler will typically <function>fork()</function> and
3110 create a sub-process to handle a new connection.
3111 Alternatively the server may be setup to create threads for each
3113 If you do use global variables and forking, you should be aware, then,
3114 that these cannot be shared between associations, unless you explicitly
3115 disable forking by command line parameters.
3118 The server provides a mechanism for controlling some of its behavior
3119 without using command-line options. The function
3122 statserv_options_block *statserv_getcontrol(void);
3125 will return a pointer to a <literal>struct statserv_options_block</literal>
3126 describing the current default settings of the server. The structure
3127 contains these elements:
3130 <term><literal>int dynamic</literal></term>
3132 A boolean value, which determines whether the server
3133 will fork on each incoming request (TRUE), or not (FALSE). Default is
3134 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3139 <term><literal>int threads</literal></term>
3141 A boolean value, which determines whether the server
3142 will create a thread on each incoming request (TRUE), or not (FALSE).
3143 Default is FALSE. This flag is only read by UNIX-based servers
3144 that offer POSIX Threads support.
3145 WIN32-based servers always operate in threaded mode.
3149 <term><literal>int inetd</literal></term>
3151 A boolean value, which determines whether the server
3152 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3156 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3157 <listitem><para>File for diagnostic output ("": stderr).
3161 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3163 Name of file for logging incoming and outgoing APDUs
3164 ("": don't log APDUs, "-":
3165 <literal>stderr</literal>).
3169 <term><literal>char default_listen[1024]</literal></term>
3170 <listitem><para>Same form as the command-line specification of
3171 listener address. "": no default listener address.
3172 Default is to listen at "tcp:@:9999". You can only
3173 specify one default listener address in this fashion.
3177 <term><literal>enum oid_proto default_proto;</literal></term>
3178 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3179 <literal>PROTO_SR</literal>.
3180 Default is <literal>PROTO_Z39_50</literal>.
3184 <term><literal>int idle_timeout;</literal></term>
3185 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3186 no (infinite) timeout. Default is 15 minutes.
3190 <term><literal>int maxrecordsize;</literal></term>
3191 <listitem><para>Maximum permissible record (message) size. Default
3192 is 64 MB. This amount of memory will only be allocated if a
3193 client requests a very large amount of records in one operation
3195 Set it to a lower number if you are worried about resource
3196 consumption on your host system.
3200 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3201 <listitem><para>Passed to the backend when a new connection is received.
3205 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3206 <listitem><para>Set user id to the user specified, after binding
3207 the listener addresses.
3212 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3214 <listitem><para>Pointer to function which is called after the
3215 command line options have been parsed - but before the server
3217 For forked UNIX servers this handler is called in the mother
3218 process; for threaded servers this handler is called in the
3220 The default value of this pointer is NULL in which case it
3221 isn't invoked by the frontend server.
3222 When the server operates as an NT service this handler is called
3223 whenever the service is started.
3228 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3230 <listitem><para>Pointer to function which is called whenever the server
3231 has stopped listening for incoming connections. This function pointer
3232 has a default value of NULL in which case it isn't called.
3233 When the server operates as an NT service this handler is called
3234 whenever the service is stopped.
3238 <term><literal>void *handle</literal></term>
3239 <listitem><para>User defined pointer (default value NULL).
3240 This is a per-server handle that can be used to specify "user-data".
3241 Do not confuse this with the session-handle as returned by bend_init.
3247 The pointer returned by <literal>statserv_getcontrol</literal> points to
3248 a static area. You are allowed to change the contents of the structure,
3249 but the changes will not take effect before you call
3252 void statserv_setcontrol(statserv_options_block *block);
3256 that you should generally update this structure before calling
3257 <function>statserv_main()</function>.
3261 <sect1 id="server.backendfunctions">
3262 <title>The Backend Functions</title>
3264 For each service of the protocol, the backend interface declares one or
3265 two functions. You are required to provide implementations of the
3266 functions representing the services that you wish to implement.
3268 <sect2 id="server.init">
3271 bend_initresult (*bend_init)(bend_initrequest *r);
3274 This handler is called once for each new connection request, after
3275 a new process/thread has been created, and an Initialize Request has
3276 been received from the client. The pointer to the
3277 <function>bend_init</function> handler is passed in the call to
3278 <function>statserv_start</function>.
3281 This handler is also called when operating in SRU mode - when
3282 a connection has been made (even though SRU does not offer
3286 Unlike previous versions of YAZ, the <function>bend_init</function> also
3287 serves as a handler that defines the Z39.50 services that the backend
3288 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3289 including search - and fetch must be specified here in this handler.
3292 The request - and result structures are defined as
3295 typedef struct bend_initrequest
3297 /** \brief user/name/password to be read */
3298 Z_IdAuthentication *auth;
3299 /** \brief encoding stream (for results) */
3301 /** \brief printing stream */
3303 /** \brief decoding stream (use stream for results) */
3305 /** \brief reference ID */
3306 Z_ReferenceId *referenceId;
3307 /** \brief peer address of client */
3310 /** \brief character set and language negotiation
3312 see include/yaz/z-charneg.h
3314 Z_CharSetandLanguageNegotiation *charneg_request;
3316 /** \brief character negotiation response */
3317 Z_External *charneg_response;
3319 /** \brief character set (encoding) for query terms
3321 This is NULL by default. It should be set to the native character
3322 set that the backend assumes for query terms */
3323 char *query_charset;
3325 /** \brief whehter query_charset also applies to recors
3327 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3328 character set as queries. If in doubt, use 0 (No).
3330 int records_in_same_charset;
3332 char *implementation_id;
3333 char *implementation_name;
3334 char *implementation_version;
3336 /** \brief Z39.50 sort handler */
3337 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3338 /** \brief SRU/Z39.50 search handler */
3339 int (*bend_search)(void *handle, bend_search_rr *rr);
3340 /** \brief SRU/Z39.50 fetch handler */
3341 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3342 /** \brief SRU/Z39.50 present handler */
3343 int (*bend_present)(void *handle, bend_present_rr *rr);
3344 /** \brief Z39.50 extended services handler */
3345 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3346 /** \brief Z39.50 delete result set handler */
3347 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3348 /** \brief Z39.50 scan handler */
3349 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3350 /** \brief Z39.50 segment facility handler */
3351 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3352 /** \brief SRU explain handler */
3353 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3354 /** \brief SRU scan handler */
3355 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3356 /** \brief SRU record update handler */
3357 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3359 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3360 int named_result_sets;
3363 typedef struct bend_initresult
3365 int errcode; /* 0==OK */
3366 char *errstring; /* system error string or NULL */
3367 void *handle; /* private handle to the backend module */
3371 In general, the server frontend expects that the
3372 <literal>bend_*result</literal> pointer that you return is valid at
3373 least until the next call to a <literal>bend_* function</literal>.
3374 This applies to all of the functions described herein. The parameter
3375 structure passed to you in the call belongs to the server frontend, and
3376 you should not make assumptions about its contents after the current
3377 function call has completed. In other words, if you want to retain any
3378 of the contents of a request structure, you should copy them.
3381 The <literal>errcode</literal> should be zero if the initialization of
3382 the backend went well. Any other value will be interpreted as an error.
3383 The <literal>errstring</literal> isn't used in the current version, but
3384 one option would be to stick it in the initResponse as a VisibleString.
3385 The <literal>handle</literal> is the most important parameter. It should
3386 be set to some value that uniquely identifies the current session to
3387 the backend implementation. It is used by the frontend server in any
3388 future calls to a backend function.
3389 The typical use is to set it to point to a dynamically allocated state
3390 structure that is private to your backend module.
3393 The <literal>auth</literal> member holds the authentication information
3394 part of the Z39.50 Initialize Request. Interpret this if your serves
3395 requires authentication.
3398 The members <literal>peer_name</literal>,
3399 <literal>implementation_id</literal>,
3400 <literal>implementation_name</literal> and
3401 <literal>implementation_version</literal> holds
3402 DNS of client, ID of implementor, name
3403 of client (Z39.50) implementation - and version.
3406 The <literal>bend_</literal> - members are set to NULL when
3407 <function>bend_init</function> is called. Modify the pointers by
3408 setting them to point to backend functions.
3411 <sect2 id="server.search.retrieve">
3412 <title>Search and Retrieve</title>
3414 We now describe the handlers that are required to support search -
3415 and retrieve. You must support two functions - one for search - and one
3416 for fetch (retrieval of one record). If desirable you can provide a
3417 third handler which is called when a present request is received which
3418 allows you to optimize retrieval of multiple-records.
3421 int (*bend_search) (void *handle, bend_search_rr *rr);
3424 char *setname; /* name to give to this set */
3425 int replace_set; /* replace set, if it already exists */
3426 int num_bases; /* number of databases in list */
3427 char **basenames; /* databases to search */
3428 Z_ReferenceId *referenceId;/* reference ID */
3429 Z_Query *query; /* query structure */
3430 ODR stream; /* encode stream */
3431 ODR decode; /* decode stream */
3432 ODR print; /* print stream */
3434 bend_request request;
3435 bend_association association;
3437 int hits; /* number of hits */
3438 int errcode; /* 0==OK */
3439 char *errstring; /* system error string or NULL */
3440 Z_OtherInformation *search_info; /* additional search info */
3441 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3442 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3443 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3444 int estimated_hit_count; /* if hit count is estimated */
3445 int partial_resultset; /* if result set is partial */
3449 The <function>bend_search</function> handler is a fairly close
3450 approximation of a protocol Z39.50 Search Request - and Response PDUs
3451 The <literal>setname</literal> is the resultSetName from the protocol.
3452 You are required to establish a mapping between the set name and whatever
3453 your backend database likes to use.
3454 Similarly, the <literal>replace_set</literal> is a boolean value
3455 corresponding to the resultSetIndicator field in the protocol.
3456 <literal>num_bases/basenames</literal> is a length of/array of character
3457 pointers to the database names provided by the client.
3458 The <literal>query</literal> is the full query structure as defined in
3459 the protocol ASN.1 specification.
3460 It can be either of the possible query types, and it's up to you to
3461 determine if you can handle the provided query type.
3462 Rather than reproduce the C interface here, we'll refer you to the
3463 structure definitions in the file
3464 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3465 attributeSetId OID of the RPN query, you can either match it against
3466 your own internal tables, or you can use the <link linkend="tools.oid">
3470 The structure contains a number of hits, and an
3471 <literal>errcode/errstring</literal> pair. If an error occurs
3472 during the search, or if you're unhappy with the request, you should
3473 set the errcode to a value from the BIB-1 diagnostic set. The value
3474 will then be returned to the user in a nonsurrogate diagnostic record
3475 in the response. The <literal>errstring</literal>, if provided, will
3476 go in the addinfo field. Look at the protocol definition for the
3477 defined error codes, and the suggested uses of the addinfo field.
3480 The <function>bend_search</function> handler is also called when
3481 the frontend server receives a SRU SearchRetrieveRequest.
3482 For SRU, a CQL query is usually provided by the client.
3483 The CQL query is available as part of <literal>Z_Query</literal>
3484 structure (note that CQL is now part of Z39.50 via an external).
3485 To support CQL in existing implementations that only do Type-1,
3486 we refer to the CQL-to-PQF tool described
3487 <link linkend="cql.to.pqf">here</link>.
3490 To maintain backwards compatibility, the frontend server
3491 of yaz always assume that error codes are BIB-1 diagnostics.
3492 For SRU operation, a Bib-1 diagnostic code is mapped to
3496 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3498 typedef struct bend_fetch_rr {
3499 char *setname; /* set name */
3500 int number; /* record number */
3501 Z_ReferenceId *referenceId;/* reference ID */
3502 Odr_oid *request_format; /* format, transfer syntax (OID) */
3503 Z_RecordComposition *comp; /* Formatting instructions */
3504 ODR stream; /* encoding stream - memory source if req */
3505 ODR print; /* printing stream */
3507 char *basename; /* name of database that provided record */
3508 int len; /* length of record or -1 if structured */
3509 char *record; /* record */
3510 int last_in_set; /* is it? */
3511 Odr_oid *output_format; /* response format/syntax (OID) */
3512 int errcode; /* 0==success */
3513 char *errstring; /* system error string or NULL */
3514 int surrogate_flag; /* surrogate diagnostic */
3515 char *schema; /* string record schema input/output */
3519 The frontend server calls the <function>bend_fetch</function> handler
3520 when it needs database records to fulfill a Z39.50 Search Request, a
3521 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3522 The <literal>setname</literal> is simply the name of the result set
3523 that holds the reference to the desired record.
3524 The <literal>number</literal> is the offset into the set (with 1
3525 being the first record in the set). The <literal>format</literal> field
3526 is the record format requested by the client (See
3527 <xref linkend="tools.oid"/>).
3528 A value of NULL for <literal>format</literal> indicates that the
3529 client did not request a specific format.
3530 The <literal>stream</literal> argument is an &odr; stream which
3531 should be used for allocating space for structured data records.
3532 The stream will be reset when all records have been assembled, and
3533 the response package has been transmitted.
3534 For unstructured data, the backend is responsible for maintaining a
3535 static or dynamic buffer for the record between calls.
3538 If a SRU SearchRetrieveRequest is received by the frontend server,
3539 the <literal>referenceId</literal> is NULL and the
3540 <literal>format</literal> (transfer syntax) is the OID for XML.
3541 The schema for SRU is stored in both the
3542 <literal>Z_RecordComposition</literal>
3543 structure and <literal>schema</literal> (simple string).
3546 In the structure, the <literal>basename</literal> is the name of the
3547 database that holds the
3548 record. <literal>len</literal> is the length of the record returned, in
3549 bytes, and <literal>record</literal> is a pointer to the record.
3550 <literal>last_in_set</literal> should be nonzero only if the record
3551 returned is the last one in the given result set.
3552 <literal>errcode</literal> and <literal>errstring</literal>, if
3553 given, will be interpreted as a global error pertaining to the
3554 set, and will be returned in a non-surrogate-diagnostic.
3555 If you wish to return the error as a surrogate-diagnostic
3556 (local error) you can do this by setting
3557 <literal>surrogate_flag</literal> to 1 also.
3560 If the <literal>len</literal> field has the value -1, then
3561 <literal>record</literal> is assumed to point to a constructed data
3562 type. The <literal>format</literal> field will be used to determine
3563 which encoder should be used to serialize the data.
3567 If your backend generates structured records, it should use
3568 <function>odr_malloc()</function> on the provided stream for allocating
3569 data: This allows the frontend server to keep track of the record sizes.
3573 The <literal>format</literal> field is mapped to an object identifier
3574 in the direct reference of the resulting EXTERNAL representation
3579 The current version of &yaz; only supports the direct reference mode.
3583 int (*bend_present) (void *handle, bend_present_rr *rr);
3586 char *setname; /* set name */
3588 int number; /* record number */
3589 Odr_oid *format; /* format, transfer syntax (OID) */
3590 Z_ReferenceId *referenceId;/* reference ID */
3591 Z_RecordComposition *comp; /* Formatting instructions */
3592 ODR stream; /* encoding stream - memory source if required */
3593 ODR print; /* printing stream */
3594 bend_request request;
3595 bend_association association;
3597 int hits; /* number of hits */
3598 int errcode; /* 0==OK */
3599 char *errstring; /* system error string or NULL */
3603 The <function>bend_present</function> handler is called when
3604 the server receives a Z39.50 Present Request.
3605 The <literal>setname</literal>,
3606 <literal>start</literal> and <literal>number</literal> is the
3607 name of the result set - start position - and number of records to
3608 be retrieved respectively. <literal>format</literal> and
3609 <literal>comp</literal> is the preferred transfer syntax and element
3610 specifications of the present request.
3613 Note that this is handler serves as a supplement for
3614 <function>bend_fetch</function> and need not to be defined in order to
3615 support search - and retrieve.
3618 <sect2 id="server.delete">
3619 <title>Delete</title>
3621 For back-ends that supports delete of a result set only one handler
3625 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3627 typedef struct bend_delete_rr {
3631 Z_ReferenceId *referenceId;
3632 int delete_status; /* status for the whole operation */
3633 int *statuses; /* status each set - indexed as setnames */
3640 The delete set function definition is rather primitive, mostly because
3641 we have had no practical need for it as of yet. If someone wants
3642 to provide a full delete service, we'd be happy to add the
3643 extra parameters that are required. Are there clients out there
3644 that will actually delete sets they no longer need?
3648 <sect2 id="server.scan">
3651 For servers that wish to offer the scan service one handler
3655 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3658 BEND_SCAN_SUCCESS, /* ok */
3659 BEND_SCAN_PARTIAL /* not all entries could be found */
3662 typedef struct bend_scan_rr {
3663 int num_bases; /* number of elements in databaselist */
3664 char **basenames; /* databases to search */
3665 Odr_oid *attributeset;
3666 Z_ReferenceId *referenceId; /* reference ID */
3667 Z_AttributesPlusTerm *term;
3668 ODR stream; /* encoding stream - memory source if required */
3669 ODR print; /* printing stream */
3671 int *step_size; /* step size */
3672 int term_position; /* desired index of term in result list/returned */
3673 int num_entries; /* number of entries requested/returned */
3675 /* scan term entries. The called handler does not have
3676 to allocate this. Size of entries is num_entries (see above) */
3677 struct scan_entry *entries;
3678 bend_scan_status status;
3681 char *scanClause; /* CQL scan clause */
3682 char *setname; /* Scan in result set (NULL if omitted) */
3686 This backend server handles both Z39.50 scan
3687 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3688 Z39.50 Scan , it must check for a non-NULL value of
3689 <literal>scanClause</literal>.
3693 if designed today, it would be a choice using a union or similar,
3694 but that would break binary compatibility with existing servers.
3699 <sect1 id="server.invocation">
3700 <title>Application Invocation</title>
3702 The finished application has the following
3703 invocation syntax (by way of <function>statserv_main()</function>):
3711 A listener specification consists of a transport mode followed by a
3712 colon (:) followed by a listener address. The transport mode is
3713 either <literal>tcp</literal>, <literal>unix:</literal> or
3714 <literal>ssl</literal>.
3717 For TCP and SSL, an address has the form
3720 hostname | IP-number [: portnumber]
3723 The port number defaults to 210 (standard Z39.50 port).
3726 For UNIX, the address is the filename of socket.
3729 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3730 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3731 IPV4 binding as well (bindv6only=0),
3732 The special hostname <literal>@4</literal> binds to
3733 <literal>INADDR_ANY</literal> (IPV4 only listener).
3734 The special hostname <literal>@6</literal> binds to
3735 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3737 <example id="server.example.running.unix">
3738 <title>Running the GFS on Unix</title>
3740 Assuming the server application <replaceable>appname</replaceable> is
3741 started as root, the following will make it listen on port 210.
3742 The server will change identity to <literal>nobody</literal>
3743 and write its log to <filename>/var/log/app.log</filename>.
3745 application -l /var/log/app.log -u nobody tcp:@:210
3749 The server will accept Z39.50 requests and offer SRU service on port 210.
3752 <example id="server.example.apache.sru">
3753 <title>Setting up Apache as SRU Frontend</title>
3755 If you use <ulink url="&url.apache;">Apache</ulink>
3756 as your public web server and want to offer HTTP port 80
3757 access to the YAZ server on 210, you can use the
3758 <ulink url="&url.apache.directive.proxypass;">
3759 <literal>ProxyPass</literal></ulink>
3761 If you have virtual host
3762 <literal>srw.mydomain</literal> you can use the following directives
3763 in Apache's httpd.conf:
3766 ErrorLog /home/srw/logs/error_log
3767 TransferLog /home/srw/logs/access_log
3768 ProxyPass / http://srw.mydomain:210/
3773 The above for the Apache 1.3 series.
3776 <example id="server.example.local.access">
3777 <title>Running a server with local access only</title>
3779 Servers that is only being accessed from the local host should listen
3780 on UNIX file socket rather than a Internet socket. To listen on
3781 <filename>/tmp/mysocket</filename> start the server as follows:
3783 application unix:/tmp/mysocket
3788 <sect1 id="server.vhosts">
3789 <title>GFS Configuration and Virtual Hosts</title>
3794 <title>The Z39.50 ASN.1 Module</title>
3795 <sect1 id="asn.introduction">
3796 <title>Introduction</title>
3798 The &asn; module provides you with a set of C struct definitions for the
3799 various PDUs of the Z39.50 protocol, as well as for the complex types
3800 appearing within the PDUs. For the primitive data types, the C
3801 representation often takes the form of an ordinary C language type,
3802 such as <literal>Odr_int</literal> which is equivalent to an integral
3803 C integer. For ASN.1 constructs that have no direct
3804 representation in C, such as general octet strings and bit strings,
3805 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3806 provides auxiliary definitions.
3809 The &asn; module is located in sub directory <filename>z39.50</filename>.
3810 There you'll find C files that implements encoders and decoders for the
3811 Z39.50 types. You'll also find the protocol definitions:
3812 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3816 <sect1 id="asn.preparing">
3817 <title>Preparing PDUs</title>
3819 A structure representing a complex ASN.1 type doesn't in itself contain the
3820 members of that type. Instead, the structure contains
3821 <emphasis>pointers</emphasis> to the members of the type.
3822 This is necessary, in part, to allow a mechanism for specifying which
3823 of the optional structure (SEQUENCE) members are present, and which
3824 are not. It follows that you will need to somehow provide space for
3825 the individual members of the structure, and set the pointers to
3826 refer to the members.
3829 The conversion routines don't care how you allocate and maintain your
3830 C structures - they just follow the pointers that you provide.
3831 Depending on the complexity of your application, and your personal
3832 taste, there are at least three different approaches that you may take
3833 when you allocate the structures.
3836 You can use static or automatic local variables in the function that
3837 prepares the PDU. This is a simple approach, and it provides the most
3838 efficient form of memory management. While it works well for flat
3839 PDUs like the InitReqest, it will generally not be sufficient for say,
3840 the generation of an arbitrarily complex RPN query structure.
3843 You can individually create the structure and its members using the
3844 <function>malloc(2)</function> function. If you want to ensure that
3845 the data is freed when it is no longer needed, you will have to
3846 define a function that individually releases each member of a
3847 structure before freeing the structure itself.
3850 You can use the <function>odr_malloc()</function> function (see
3851 <xref linkend="odr.use"/> for details). When you use
3852 <function>odr_malloc()</function>, you can release all of the
3853 allocated data in a single operation, independent of any pointers and
3854 relations between the data. <function>odr_malloc()</function> is based on a
3855 "nibble-memory"
3856 scheme, in which large portions of memory are allocated, and then
3857 gradually handed out with each call to <function>odr_malloc()</function>.
3858 The next time you call <function>odr_reset()</function>, all of the
3859 memory allocated since the last call is recycled for future use (actually,
3860 it is placed on a free-list).
3863 You can combine all of the methods described here. This will often be
3864 the most practical approach. For instance, you might use
3865 <function>odr_malloc()</function> to allocate an entire structure and
3866 some of its elements, while you leave other elements pointing to global
3867 or per-session default variables.
3870 The &asn; module provides an important aid in creating new PDUs. For
3871 each of the PDU types (say, <function>Z_InitRequest</function>), a
3872 function is provided that allocates and initializes an instance of
3873 that PDU type for you. In the case of the InitRequest, the function is
3874 simply named <function>zget_InitRequest()</function>, and it sets up
3875 reasonable default value for all of the mandatory members. The optional
3876 members are generally initialized to null pointers. This last aspect
3877 is very important: it ensures that if the PDU definitions are
3878 extended after you finish your implementation (to accommodate
3879 new versions of the protocol, say), you won't get into trouble with
3880 uninitialized pointers in your structures. The functions use
3881 <function>odr_malloc()</function> to
3882 allocate the PDUs and its members, so you can free everything again with a
3883 single call to <function>odr_reset()</function>. We strongly recommend
3884 that you use the <literal>zget_*</literal>
3885 functions whenever you are preparing a PDU (in a C++ API, the
3886 <literal>zget_</literal>
3887 functions would probably be promoted to constructors for the
3891 The prototype for the individual PDU types generally look like this:
3894 Z_<type> *zget_<type>(ODR o);
3900 Z_InitRequest *zget_InitRequest(ODR o);
3903 The &odr; handle should generally be your encoding stream, but it
3907 As well as the individual PDU functions, a function
3908 <function>zget_APDU()</function> is provided, which allocates
3909 a top-level Z-APDU of the type requested:
3912 Z_APDU *zget_APDU(ODR o, int which);
3915 The <varname>which</varname> parameter is (of course) the discriminator
3916 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
3917 All of the interface described here is provided by the &asn; module, and
3918 you access it through the <filename>proto.h</filename> header file.
3921 <sect1 id="asn.external">
3922 <title>EXTERNAL Data</title>
3924 In order to achieve extensibility and adaptability to different
3925 application domains, the new version of the protocol defines many
3926 structures outside of the main ASN.1 specification, referencing them
3927 through ASN.1 EXTERNAL constructs. To simplify the construction and
3928 access to the externally referenced data, the &asn; module defines a
3929 specialized version of the EXTERNAL construct, called
3930 <literal>Z_External</literal>.It is defined thus:
3933 typedef struct Z_External
3935 Odr_oid *direct_reference;
3936 int *indirect_reference;
3941 Z_External_single = 0,
3943 Z_External_arbitrary,
3945 /* Specific types */
3947 Z_External_explainRecord,
3948 Z_External_resourceReport1,
3949 Z_External_resourceReport2
3957 Odr_any *single_ASN1_type;
3958 Odr_oct *octet_aligned;
3959 Odr_bitmask *arbitrary;
3961 /* Specific types */
3963 Z_ExplainRecord *explainRecord;
3964 Z_ResourceReport1 *resourceReport1;
3965 Z_ResourceReport2 *resourceReport2;
3973 When decoding, the &asn; module will attempt to determine which
3974 syntax describes the data by looking at the reference fields
3975 (currently only the direct-reference). For ASN.1 structured data, you
3976 need only consult the <literal>which</literal> field to determine the
3977 type of data. You can the access the data directly through the union.
3978 When constructing data for encoding, you set the union pointer to point
3979 to the data, and set the <literal>which</literal> field accordingly.
3980 Remember also to set the direct (or indirect) reference to the correct
3981 OID for the data type.
3982 For non-ASN.1 data such as MARC records, use the
3983 <literal>octet_aligned</literal> arm of the union.
3986 Some servers return ASN.1 structured data values (eg. database
3987 records) as BER-encoded records placed in the
3988 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
3989 The ASN-module will <emphasis>not</emphasis> automatically decode
3990 these records. To help you decode the records in the application, the
3994 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
3997 Can be used to retrieve information about the known, external data
3998 types. The function return a pointer to a static area, or NULL, if no
3999 match for the given direct reference is found. The
4000 <literal>Z_ext_typeent</literal>
4004 typedef struct Z_ext_typeent
4006 int oid[OID_SIZE]; /* the direct-reference OID. */
4007 int what; /* discriminator value for the external CHOICE */
4008 Odr_fun fun; /* decoder function */
4012 The <literal>what</literal> member contains the
4013 <literal>Z_External</literal> union discriminator value for the
4014 given type: For the SUTRS record syntax, the value would be
4015 <literal>Z_External_sutrs</literal>.
4016 The <literal>fun</literal> member contains a pointer to the
4017 function which encodes/decodes the given type. Again, for the SUTRS
4018 record syntax, the value of <literal>fun</literal> would be
4019 <literal>z_SUTRS</literal> (a function pointer).
4022 If you receive an EXTERNAL which contains an octet-string value that
4023 you suspect of being an ASN.1-structured data value, you can use
4024 <literal>z_ext_gettypebyref</literal> to look for the provided
4026 If the return value is different from NULL, you can use the provided
4027 function to decode the BER string (see <xref linkend="odr.use"/>
4031 If you want to <emphasis>send</emphasis> EXTERNALs containing
4032 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4033 is possible too. However, on the encoding phase, it requires a somewhat
4034 involved juggling around of the various buffers involved.
4037 If you need to add new, externally defined data types, you must update
4038 the struct above, in the source file <filename>prt-ext.h</filename>, as
4039 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4040 When changing the latter, remember to update both the
4041 <literal>arm</literal> arrary and the list
4042 <literal>type_table</literal>, which drives the CHOICE biasing that
4043 is necessary to tell the different, structured types apart
4048 Eventually, the EXTERNAL processing will most likely
4049 automatically insert the correct OIDs or indirect-refs. First,
4050 however, we need to determine how application-context management
4051 (specifically the presentation-context-list) should fit into the
4056 <sect1 id="asn.pdu">
4057 <title>PDU Contents Table</title>
4059 We include, for reference, a listing of the fields of each top-level
4060 PDU, as well as their default settings.
4062 <table frame="top" id="asn.default.initialize.request">
4063 <title>Default settings for PDU Initialize Request</title>
4065 <colspec colwidth="7*" colname="field"></colspec>
4066 <colspec colwidth="5*" colname="type"></colspec>
4067 <colspec colwidth="7*" colname="value"></colspec>
4070 <entry>Field</entry>
4072 <entry>Default Value</entry>
4077 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4080 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4083 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4086 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4089 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4092 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4095 implementationId</entry><entry>char*</entry><entry>"81"
4098 implementationName</entry><entry>char*</entry><entry>"YAZ"
4101 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4104 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4107 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4112 <table frame="top" id="asn.default.initialize.response">
4113 <title>Default settings for PDU Initialize Response</title>
4115 <colspec colwidth="7*" colname="field"></colspec>
4116 <colspec colwidth="5*" colname="type"></colspec>
4117 <colspec colwidth="7*" colname="value"></colspec>
4120 <entry>Field</entry>
4122 <entry>Default Value</entry>
4127 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4130 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4133 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4136 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4139 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4142 result</entry><entry>Odr_bool</entry><entry>TRUE
4145 implementationId</entry><entry>char*</entry><entry>"id)"
4148 implementationName</entry><entry>char*</entry><entry>"YAZ"
4151 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4154 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4157 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4162 <table frame="top" id="asn.default.search.request">
4163 <title>Default settings for PDU Search Request</title>
4165 <colspec colwidth="7*" colname="field"></colspec>
4166 <colspec colwidth="5*" colname="type"></colspec>
4167 <colspec colwidth="7*" colname="value"></colspec>
4170 <entry>Field</entry>
4172 <entry>Default Value</entry>
4177 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4180 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4183 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4186 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4189 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4192 resultSetName</entry><entry>char *</entry><entry>"default"
4195 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4198 databaseNames</entry><entry>char **</entry><entry>NULL
4201 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4205 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4209 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4212 query</entry><entry>Z_Query</entry><entry>NULL
4215 additionalSearchInfo</entry><entry>Z_OtherInformation
4219 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4224 <table frame="top" id="asn.default.search.response">
4225 <title>Default settings for PDU Search Response</title>
4227 <colspec colwidth="7*" colname="field"></colspec>
4228 <colspec colwidth="5*" colname="type"></colspec>
4229 <colspec colwidth="7*" colname="value"></colspec>
4232 <entry>Field</entry>
4234 <entry>Default Value</entry>
4239 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4242 resultCount</entry><entry>Odr_int</entry><entry>0
4245 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4248 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4251 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4254 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4257 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4260 records</entry><entry>Z_Records</entry><entry>NULL
4263 additionalSearchInfo</entry>
4264 <entry>Z_OtherInformation</entry><entry>NULL
4267 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4272 <table frame="top" id="asn.default.present.request">
4273 <title>Default settings for PDU Present Request</title>
4275 <colspec colwidth="7*" colname="field"></colspec>
4276 <colspec colwidth="5*" colname="type"></colspec>
4277 <colspec colwidth="7*" colname="value"></colspec>
4280 <entry>Field</entry>
4282 <entry>Default Value</entry>
4287 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4290 resultSetId</entry><entry>char*</entry><entry>"default"
4293 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4296 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4299 num_ranges</entry><entry>Odr_int</entry><entry>0
4302 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4305 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4308 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4311 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4314 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4317 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4320 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4325 <table frame="top" id="asn.default.present.response">
4326 <title>Default settings for PDU Present Response</title>
4328 <colspec colwidth="7*" colname="field"></colspec>
4329 <colspec colwidth="5*" colname="type"></colspec>
4330 <colspec colwidth="7*" colname="value"></colspec>
4333 <entry>Field</entry>
4335 <entry>Default Value</entry>
4340 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4343 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4346 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4349 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4352 records</entry><entry>Z_Records</entry><entry>NULL
4355 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4360 <table frame="top" id="asn.default.delete.result.set.request">
4361 <title>Default settings for Delete Result Set Request</title>
4363 <colspec colwidth="7*" colname="field"></colspec>
4364 <colspec colwidth="5*" colname="type"></colspec>
4365 <colspec colwidth="7*" colname="value"></colspec>
4368 <entry>Field</entry>
4370 <entry>Default Value</entry>
4374 <row><entry>referenceId
4375 </entry><entry>Z_ReferenceId</entry><entry>NULL
4378 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4381 num_ids</entry><entry>Odr_int</entry><entry>0
4384 resultSetList</entry><entry>char**</entry><entry>NULL
4387 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4392 <table frame="top" id="asn.default.delete.result.set.response">
4393 <title>Default settings for Delete Result Set Response</title>
4395 <colspec colwidth="7*" colname="field"></colspec>
4396 <colspec colwidth="5*" colname="type"></colspec>
4397 <colspec colwidth="7*" colname="value"></colspec>
4400 <entry>Field</entry>
4402 <entry>Default Value</entry>
4407 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4410 deleteOperationStatus</entry><entry>Odr_int</entry>
4411 <entry>Z_DeleteStatus_success</entry></row>
4413 num_statuses</entry><entry>Odr_int</entry><entry>0
4416 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4419 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4422 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4425 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4428 deleteMessage</entry><entry>char*</entry><entry>NULL
4431 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4436 <table frame="top" id="asn.default.scan.request">
4437 <title>Default settings for Scan Request</title>
4439 <colspec colwidth="7*" colname="field"></colspec>
4440 <colspec colwidth="5*" colname="type"></colspec>
4441 <colspec colwidth="7*" colname="value"></colspec>
4444 <entry>Field</entry>
4446 <entry>Default Value</entry>
4451 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4454 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4457 databaseNames</entry><entry>char**</entry><entry>NULL
4460 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4463 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4464 </entry><entry>NULL</entry></row>
4466 stepSize</entry><entry>Odr_int</entry><entry>NULL
4469 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4472 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4475 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4480 <table frame="top" id="asn.default.scan.response">
4481 <title>Default settings for Scan Response</title>
4483 <colspec colwidth="7*" colname="field"></colspec>
4484 <colspec colwidth="5*" colname="type"></colspec>
4485 <colspec colwidth="7*" colname="value"></colspec>
4488 <entry>Field</entry>
4490 <entry>Default Value</entry>
4495 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4498 stepSize</entry><entry>Odr_int</entry><entry>NULL
4501 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4504 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4507 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4510 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4513 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4516 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4521 <table frame="top" id="asn.default.trigger.resource.control.request">
4522 <title>Default settings for Trigger Resource Control Request</title>
4524 <colspec colwidth="7*" colname="field"></colspec>
4525 <colspec colwidth="5*" colname="type"></colspec>
4526 <colspec colwidth="7*" colname="value"></colspec>
4529 <entry>Field</entry>
4531 <entry>Default Value</entry>
4536 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4539 requestedAction</entry><entry>Odr_int</entry><entry>
4540 Z_TriggerResourceCtrl_resou..
4543 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4546 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4549 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4554 <table frame="top" id="asn.default.resource.control.request">
4555 <title>Default settings for Resource Control Request</title>
4557 <colspec colwidth="7*" colname="field"></colspec>
4558 <colspec colwidth="5*" colname="type"></colspec>
4559 <colspec colwidth="7*" colname="value"></colspec>
4562 <entry>Field</entry>
4564 <entry>Default Value</entry>
4569 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4572 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4575 resourceReport</entry><entry>Z_External</entry><entry>NULL
4578 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4581 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4584 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4587 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4592 <table frame="top" id="asn.default.resource.control.response">
4593 <title>Default settings for Resource Control Response</title>
4595 <colspec colwidth="7*" colname="field"></colspec>
4596 <colspec colwidth="5*" colname="type"></colspec>
4597 <colspec colwidth="7*" colname="value"></colspec>
4600 <entry>Field</entry>
4602 <entry>Default Value</entry>
4607 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4610 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4613 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4616 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4621 <table frame="top" id="asn.default.access.control.request">
4622 <title>Default settings for Access Control Request</title>
4624 <colspec colwidth="7*" colname="field"></colspec>
4625 <colspec colwidth="5*" colname="type"></colspec>
4626 <colspec colwidth="7*" colname="value"></colspec>
4629 <entry>Field</entry>
4631 <entry>Default Value</entry>
4636 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4639 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4642 u</entry><entry>union</entry><entry>NULL
4645 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4650 <table frame="top" id="asn.default.access.control.response">
4651 <title>Default settings for Access Control Response</title>
4653 <colspec colwidth="7*" colname="field"></colspec>
4654 <colspec colwidth="5*" colname="type"></colspec>
4655 <colspec colwidth="7*" colname="value"></colspec>
4658 <entry>Field</entry>
4660 <entry>Default Value</entry>
4665 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4668 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4671 u</entry><entry>union</entry><entry>NULL
4674 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4677 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4682 <table frame="top" id="asn.default.segment">
4683 <title>Default settings for Segment</title>
4685 <colspec colwidth="7*" colname="field"></colspec>
4686 <colspec colwidth="5*" colname="type"></colspec>
4687 <colspec colwidth="7*" colname="value"></colspec>
4690 <entry>Field</entry>
4692 <entry>Default Value</entry>
4697 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4700 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4703 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4706 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4708 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4713 <table frame="top" id="asn.default.close">
4714 <title>Default settings for Close</title>
4716 <colspec colwidth="7*" colname="field"></colspec>
4717 <colspec colwidth="5*" colname="type"></colspec>
4718 <colspec colwidth="7*" colname="value"></colspec>
4721 <entry>Field</entry>
4723 <entry>Default Value</entry>
4728 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4731 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4734 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4737 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4740 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4743 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4751 <title>SOAP and SRU</title>
4752 <sect1 id="soap.introduction">
4753 <title>Introduction</title>
4755 &yaz; uses a very simple implementation of
4756 <ulink url="&url.soap;">SOAP</ulink> that only,
4757 currenly, supports what is sufficient to offer SRU SOAP functionality.
4758 The implementation uses the
4759 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4760 libxml2 to encode and decode SOAP packages.
4763 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4764 simple C structs to represent SOAP packages as well as
4768 <sect1 id="soap.http">
4771 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4772 relatively easy to change that.
4775 The following definition of <literal>Z_GDU</literal> (Generic Data
4776 Unit) allows for both HTTP and Z39.50 in one packet.
4779 #include <yaz/zgdu.h>
4781 #define Z_GDU_Z3950 1
4782 #define Z_GDU_HTTP_Request 2
4783 #define Z_GDU_HTTP_Response 3
4788 Z_HTTP_Request *HTTP_Request;
4789 Z_HTTP_Response *HTTP_Response;
4794 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4795 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4797 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4798 is the HTTP Request and Response respectively.
4801 <sect1 id="soap.xml">
4802 <title>SOAP Packages</title>
4804 Every SOAP package in &yaz; is represented as follows:
4806 #include <yaz/soap.h>
4820 #define Z_SOAP_fault 1
4821 #define Z_SOAP_generic 2
4822 #define Z_SOAP_error 3
4826 Z_SOAP_Fault *fault;
4827 Z_SOAP_Generic *generic;
4828 Z_SOAP_Fault *soap_error;
4835 The <literal>fault</literal> and <literal>soap_error</literal>
4836 arms represent both a SOAP fault - struct
4837 <literal>Z_SOAP_Fault</literal>. Any other generic
4838 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
4841 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
4842 is the namespace for SOAP itself and reflects the SOAP
4843 version. For version 1.1 it is
4844 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
4845 for version 1.2 it is
4846 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
4849 int z_soap_codec(ODR o, Z_SOAP **pp,
4850 char **content_buf, int *content_len,
4851 Z_SOAP_Handler *handlers);
4854 The <literal>content_buf</literal> and <literal>content_len</literal>
4855 is XML buffer and length of buffer respectively.
4858 The <literal>handlers</literal> is a list of SOAP codec
4859 handlers - one handler for each service namespace. For SRU SOAP, the
4860 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
4863 When decoding, the <function>z_soap_codec</function>
4864 inspects the XML content
4865 and tries to match one of the services namespaces of the
4866 supplied handlers. If there is a match a handler function
4867 is invoked which decodes that particular SOAP package.
4868 If successful, the returned <literal>Z_SOAP</literal> package will be
4869 of type <literal>Z_SOAP_Generic</literal>.
4870 Member <literal>no</literal> is
4871 set the offset of handler that matched; <literal>ns</literal>
4872 is set to namespace of matching handler; the void pointer
4873 <literal>p</literal> is set to the C data structure assocatiated
4877 When a NULL namespace is met (member <literal>ns</literal> bwlow),
4878 that specifies end-of-list.
4881 Each handler is defined as follows:
4889 The <literal>ns</literal> is namespace of service associated with
4890 handler <literal>f</literal>. <literal>client_data</literal>
4891 is user-defined data which is passed to handler.
4894 The prototype for a SOAP service handler is:
4896 int handler(ODR o, void * ptr, void **handler_data,
4897 void *client_data, const char *ns);
4899 The <parameter>o</parameter> specifies the mode (decode/encode)
4900 as usual. The second argument, <parameter>ptr</parameter>,
4901 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
4902 and is a pointer to the <literal>Body</literal> element
4903 of the SOAP package. The <parameter>handler_data</parameter>
4904 is an opaque pointer to a C definitions associated with the
4905 SOAP service. <parameter>client_data</parameter> is the pointer
4906 which was set as part of the <literal>Z_SOAP_handler</literal>.
4907 Finally, <parameter>ns</parameter> the service namespace.
4910 <sect1 id="soap.srw">
4913 SRU SOAP is just one implementation of a SOAP handler as described
4914 in the previous section.
4915 The encoder/decoder handler for SRU is defined as
4918 #include <yaz/srw.h>
4920 int yaz_srw_codec(ODR o, void * pptr,
4921 Z_SRW_GDU **handler_data,
4922 void *client_data, const char *ns);
4924 Here, <literal>Z_SRW_GDU</literal> is either
4925 searchRetrieveRequest or a searchRetrieveResponse.
4929 The xQuery and xSortKeys are not handled yet by
4930 the SRW implementation of &yaz;. Explain is also missing.
4931 Future versions of &yaz; will include these features.
4935 The definition of searchRetrieveRequest is:
4939 #define Z_SRW_query_type_cql 1
4940 #define Z_SRW_query_type_xcql 2
4941 #define Z_SRW_query_type_pqf 3
4949 #define Z_SRW_sort_type_none 1
4950 #define Z_SRW_sort_type_sort 2
4951 #define Z_SRW_sort_type_xSort 3
4959 int *maximumRecords;
4961 char *recordPacking;
4963 } Z_SRW_searchRetrieveRequest;
4965 Please observe that data of type xsd:string is represented
4966 as a char pointer (<literal>char *</literal>). A null pointer
4967 means that the element is absent.
4968 Data of type xsd:integer is representd as a pointer to
4969 an int (<literal>int *</literal>). Again, a null pointer
4970 us used for absent elements.
4973 The SearchRetrieveResponse has the following definition.
4976 int * numberOfRecords;
4978 int * resultSetIdleTime;
4980 Z_SRW_record *records;
4983 Z_SRW_diagnostic *diagnostics;
4984 int num_diagnostics;
4985 int *nextRecordPosition;
4986 } Z_SRW_searchRetrieveResponse;
4988 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
4989 is number of returned records and diagnostics respectively and also
4990 correspond to the "size of" arrays <literal>records</literal>
4991 and <literal>diagnostics</literal>.
4994 A retrieval record is defined as follows:
4998 char *recordData_buf;
5000 int *recordPosition;
5003 The record data is defined as a buffer of some length so that
5004 data can be of any type. SRW 1.0 currenly doesn't allow for this
5005 (only XML), but future versions might do.
5008 And, a diagnostic as:
5018 <chapter id="tools">
5019 <title>Supporting Tools</title>
5021 In support of the service API - primarily the ASN module, which
5022 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5023 a collection of tools that support the development of applications.
5025 <sect1 id="tools.query">
5026 <title>Query Syntax Parsers</title>
5028 Since the type-1 (RPN) query structure has no direct, useful string
5029 representation, every origin application needs to provide some form of
5030 mapping from a local query notation or representation to a
5031 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5032 construct the query manually, perhaps using
5033 <function>odr_malloc()</function> to simplify memory management.
5034 The &yaz; distribution includes three separate, query-generating tools
5035 that may be of use to you.
5038 <title>Prefix Query Format</title>
5040 Since RPN or reverse polish notation is really just a fancy way of
5041 describing a suffix notation format (operator follows operands), it
5042 would seem that the confusion is total when we now introduce a prefix
5043 notation for RPN. The reason is one of simple laziness - it's somewhat
5044 simpler to interpret a prefix format, and this utility was designed
5045 for maximum simplicity, to provide a baseline representation for use
5046 in simple test applications and scripting environments (like Tcl). The
5047 demonstration client included with YAZ uses the PQF.
5051 The PQF have been adopted by other parties developing Z39.50
5052 software. It is often referred to as Prefix Query Notation
5057 The PQF is defined by the pquery module in the YAZ library.
5058 There are two sets of function that have similar behavior. First
5059 set operates on a PQF parser handle, second set doesn't. First set
5060 set of functions are more flexible than the second set. Second set
5061 is obsolete and is only provided to ensure backwards compatibility.
5064 First set of functions all operate on a PQF parser handle:
5067 #include <yaz/pquery.h>
5069 YAZ_PQF_Parser yaz_pqf_create(void);
5071 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5073 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5075 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5076 Odr_oid **attributeSetId, const char *qbuf);
5078 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5081 A PQF parser is created and destructed by functions
5082 <function>yaz_pqf_create</function> and
5083 <function>yaz_pqf_destroy</function> respectively.
5084 Function <function>yaz_pqf_parse</function> parses query given
5085 by string <literal>qbuf</literal>. If parsing was successful,
5086 a Z39.50 RPN Query is returned which is created using ODR stream
5087 <literal>o</literal>. If parsing failed, a NULL pointer is
5089 Function <function>yaz_pqf_scan</function> takes a scan query in
5090 <literal>qbuf</literal>. If parsing was successful, the function
5091 returns attributes plus term pointer and modifies
5092 <literal>attributeSetId</literal> to hold attribute set for the
5093 scan request - both allocated using ODR stream <literal>o</literal>.
5094 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5095 Error information for bad queries can be obtained by a call to
5096 <function>yaz_pqf_error</function> which returns an error code and
5097 modifies <literal>*msg</literal> to point to an error description,
5098 and modifies <literal>*off</literal> to the offset within last
5099 query were parsing failed.
5102 The second set of functions are declared as follows:
5105 #include <yaz/pquery.h>
5107 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5109 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5110 Odr_oid **attributeSetP, const char *qbuf);
5112 int p_query_attset(const char *arg);
5115 The function <function>p_query_rpn()</function> takes as arguments an
5116 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5117 to provide a memory source (the structure created is released on
5118 the next call to <function>odr_reset()</function> on the stream), a
5119 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5120 <token>PROTO_SR</token>), an attribute set reference, and
5121 finally a null-terminated string holding the query string.
5124 If the parse went well, <function>p_query_rpn()</function> returns a
5125 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5126 placed directly into a <literal>Z_SearchRequest</literal>.
5127 If parsing failed, due to syntax error, a NULL pointer is returned.
5130 The <literal>p_query_attset</literal> specifies which attribute set
5131 to use if the query doesn't specify one by the
5132 <literal>@attrset</literal> operator.
5133 The <literal>p_query_attset</literal> returns 0 if the argument is a
5134 valid attribute set specifier; otherwise the function returns -1.
5137 The grammar of the PQF is as follows:
5140 query ::= top-set query-struct.
5142 top-set ::= [ '@attrset' string ]
5144 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5146 attr-spec ::= '@attr' [ string ] string query-struct
5148 complex ::= operator query-struct query-struct.
5150 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5152 simple ::= result-set | term.
5154 result-set ::= '@set' string.
5158 proximity ::= exclusion distance ordered relation which-code unit-code.
5160 exclusion ::= '1' | '0' | 'void'.
5162 distance ::= integer.
5164 ordered ::= '1' | '0'.
5166 relation ::= integer.
5168 which-code ::= 'known' | 'private' | integer.
5170 unit-code ::= integer.
5172 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5175 You will note that the syntax above is a fairly faithful
5176 representation of RPN, except for the Attribute, which has been
5177 moved a step away from the term, allowing you to associate one or more
5178 attributes with an entire query structure. The parser will
5179 automatically apply the given attributes to each term as required.
5182 The @attr operator is followed by an attribute specification
5183 (<literal>attr-spec</literal> above). The specification consists
5184 of an optional attribute set, an attribute type-value pair and
5185 a sub-query. The attribute type-value pair is packed in one string:
5186 an attribute type, an equals sign, and an attribute value, like this:
5187 <literal>@attr 1=1003</literal>.
5188 The type is always an integer but the value may be either an
5189 integer or a string (if it doesn't start with a digit character).
5190 A string attribute-value is encoded as a Type-1 ``complex''
5191 attribute with the list of values containing the single string
5192 specified, and including no semantic indicators.
5195 Version 3 of the Z39.50 specification defines various encoding of terms.
5196 Use <literal>@term </literal> <replaceable>type</replaceable>
5197 <replaceable>string</replaceable>,
5198 where type is one of: <literal>general</literal>,
5199 <literal>numeric</literal> or <literal>string</literal>
5200 (for InternationalString).
5201 If no term type has been given, the <literal>general</literal> form
5202 is used. This is the only encoding allowed in both versions 2 and 3
5203 of the Z39.50 standard.
5205 <sect3 id="PQF-prox">
5206 <title>Using Proximity Operators with PQF</title>
5209 This is an advanced topic, describing how to construct
5210 queries that make very specific requirements on the
5211 relative location of their operands.
5212 You may wish to skip this section and go straight to
5213 <link linkend="pqf-examples">the example PQF queries</link>.
5218 Most Z39.50 servers do not support proximity searching, or
5219 support only a small subset of the full functionality that
5220 can be expressed using the PQF proximity operator. Be
5221 aware that the ability to <emphasis>express</emphasis> a
5222 query in PQF is no guarantee that any given server will
5223 be able to <emphasis>execute</emphasis> it.
5229 The proximity operator <literal>@prox</literal> is a special
5230 and more restrictive version of the conjunction operator
5231 <literal>@and</literal>. Its semantics are described in
5232 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5233 can be read on-line at
5234 <ulink url="&url.z39.50.proximity;"/>
5237 In PQF, the proximity operation is represented by a sequence
5240 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5242 in which the meanings of the parameters are as described in in
5243 the standard, and they can take the following values:
5246 <formalpara><title>exclusion</title>
5248 0 = false (i.e. the proximity condition specified by the
5249 remaining parameters must be satisfied) or
5250 1 = true (the proximity condition specified by the
5251 remaining parameters must <emphasis>not</emphasis> be
5257 <formalpara><title>distance</title><para>
5258 An integer specifying the difference between the locations
5259 of the operands: e.g. two adjacent words would have
5260 distance=1 since their locations differ by one unit.
5262 </formalpara></listitem>
5264 <formalpara><title>ordered</title><para>
5265 1 = ordered (the operands must occur in the order the
5266 query specifies them) or
5267 0 = unordered (they may appear in either order).
5272 <formalpara><title>relation</title><para>
5273 Recognised values are
5275 2 (lessThanOrEqual),
5277 4 (greaterThanOrEqual),
5284 <formalpara><title>which-code</title><para>
5285 <literal>known</literal>
5287 <literal>k</literal>
5288 (the unit-code parameter is taken from the well-known list
5289 of alternatives described in below) or
5290 <literal>private</literal>
5292 <literal>p</literal>
5293 (the unit-code paramater has semantics specific to an
5294 out-of-band agreement such as a profile).
5299 <formalpara><title>unit-code</title><para>
5300 If the which-code parameter is <literal>known</literal>
5301 then the recognised values are
5311 10 (elementType) and
5313 If which-code is <literal>private</literal> then the
5314 acceptable values are determined by the profile.
5319 (The numeric values of the relation and well-known unit-code
5320 parameters are taken straight from
5321 <ulink url="&url.z39.50.proximity.asn1;"
5322 >the ASN.1</ulink> of the proximity structure in the standard.)
5325 <sect3 id="pqf-examples">
5326 <title>PQF queries</title>
5327 <example id="example.pqf.simple.terms">
5328 <title>PQF queries using simple terms</title>
5337 <example id="pqf.example.pqf.boolean.operators">
5338 <title>PQF boolean operators</title>
5341 @or "dylan" "zimmerman"
5343 @and @or dylan zimmerman when
5345 @and when @or dylan zimmerman
5349 <example id="example.pqf.result.sets">
5350 <title>PQF references to result sets</title>
5355 @and @set seta @set setb
5359 <example id="example.pqf.attributes">
5360 <title>Attributes for terms</title>
5365 @attr 1=4 @attr 4=1 "self portrait"
5367 @attrset exp1 @attr 1=1 CategoryList
5369 @attr gils 1=2008 Copenhagen
5371 @attr 1=/book/title computer
5375 <example id="example.pqf.proximity">
5376 <title>PQF Proximity queries</title>
5379 @prox 0 3 1 2 k 2 dylan zimmerman
5381 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5382 distance, ordered, relation, which-code and unit-code, in that
5386 <para>exclusion = 0: the proximity condition must hold</para>
5389 <para>distance = 3: the terms must be three units apart</para>
5393 ordered = 1: they must occur in the order they are specified
5398 relation = 2: lessThanOrEqual (to the distance of 3 units)
5403 which-code is ``known'', so the standard unit-codes are used
5407 <para>unit-code = 2: word.</para>
5410 So the whole proximity query means that the words
5411 <literal>dylan</literal> and <literal>zimmerman</literal> must
5412 both occur in the record, in that order, differing in position
5413 by three or fewer words (i.e. with two or fewer words between
5414 them.) The query would find ``Bob Dylan, aka. Robert
5415 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5416 since the distance in this case is four.
5419 <example id="example.pqf.search.term.type">
5420 <title>PQF specification of search term type</title>
5423 @term string "a UTF-8 string, maybe?"
5427 <example id="example.pqf.mixed.queries">
5428 <title>PQF mixed queries</title>
5431 @or @and bob dylan @set Result-1
5433 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5435 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5437 The last of these examples is a spatial search: in
5438 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5439 >the GILS attribute set</ulink>,
5441 2038 indicates West Bounding Coordinate and
5442 2030 indicates East Bounding Coordinate,
5443 so the query is for areas extending from -114 degrees
5444 to no more than -109 degrees.
5449 <sect2 id="CCL"><title>CCL</title>
5451 Not all users enjoy typing in prefix query structures and numerical
5452 attribute values, even in a minimalistic test client. In the library
5453 world, the more intuitive Common Command Language - CCL (ISO 8777)
5454 has enjoyed some popularity - especially before the widespread
5455 availability of graphical interfaces. It is still useful in
5456 applications where you for some reason or other need to provide a
5457 symbolic language for expressing boolean query structures.
5459 <sect3 id="ccl.syntax">
5460 <title>CCL Syntax</title>
5462 The CCL parser obeys the following grammar for the FIND argument.
5463 The syntax is annotated by in the lines prefixed by
5464 <literal>--</literal>.
5467 CCL-Find ::= CCL-Find Op Elements
5470 Op ::= "and" | "or" | "not"
5471 -- The above means that Elements are separated by boolean operators.
5473 Elements ::= '(' CCL-Find ')'
5476 | Qualifiers Relation Terms
5477 | Qualifiers Relation '(' CCL-Find ')'
5478 | Qualifiers '=' string '-' string
5479 -- Elements is either a recursive definition, a result set reference, a
5480 -- list of terms, qualifiers followed by terms, qualifiers followed
5481 -- by a recursive definition or qualifiers in a range (lower - upper).
5483 Set ::= 'set' = string
5484 -- Reference to a result set
5486 Terms ::= Terms Prox Term
5488 -- Proximity of terms.
5490 Term ::= Term string
5492 -- This basically means that a term may include a blank
5494 Qualifiers ::= Qualifiers ',' string
5496 -- Qualifiers is a list of strings separated by comma
5498 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5499 -- Relational operators. This really doesn't follow the ISO8777
5503 -- Proximity operator
5506 <example id="example.ccl.queries">
5507 <title>CCL queries</title>
5509 The following queries are all valid:
5520 (dylan and bob) or set=1
5529 Assuming that the qualifiers <literal>ti</literal>,
5530 <literal>au</literal>
5531 and <literal>date</literal> are defined we may use:
5536 au=(bob dylan and slow train coming)
5538 date>1980 and (ti=((self portrait)))
5542 <sect3 id="ccl.qualifiers">
5543 <title>CCL Qualifiers</title>
5545 Qualifiers are used to direct the search to a particular searchable
5546 index, such as title (ti) and author indexes (au). The CCL standard
5547 itself doesn't specify a particular set of qualifiers, but it does
5548 suggest a few short-hand notations. You can customize the CCL parser
5549 to support a particular set of qualifiers to reflect the current target
5550 profile. Traditionally, a qualifier would map to a particular
5551 use-attribute within the BIB-1 attribute set. It is also
5552 possible to set other attributes, such as the structure
5556 A CCL profile is a set of predefined CCL qualifiers that may be
5557 read from a file or set in the CCL API.
5558 The YAZ client reads its CCL qualifiers from a file named
5559 <filename>default.bib</filename>. There are four types of
5560 lines in a CCL profile: qualifier specification,
5561 qualifier alias, comments and directives.
5563 <sect4 id="ccl.qualifier.specification">
5564 <title>Qualifier specification</title>
5566 A qualifier specification is of the form:
5569 <replaceable>qualifier-name</replaceable>
5570 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5571 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5574 where <replaceable>qualifier-name</replaceable> is the name of the
5575 qualifier to be used (eg. <literal>ti</literal>),
5576 <replaceable>type</replaceable> is attribute type in the attribute
5577 set (Bib-1 is used if no attribute set is given) and
5578 <replaceable>val</replaceable> is attribute value.
5579 The <replaceable>type</replaceable> can be specified as an
5580 integer or as it be specified either as a single-letter:
5581 <literal>u</literal> for use,
5582 <literal>r</literal> for relation,<literal>p</literal> for position,
5583 <literal>s</literal> for structure,<literal>t</literal> for truncation
5584 or <literal>c</literal> for completeness.
5585 The attributes for the special qualifier name <literal>term</literal>
5586 are used when no CCL qualifier is given in a query.
5587 <table id="ccl.common.bib1.attributes">
5588 <title>Common Bib-1 attributes</title>
5590 <colspec colwidth="2*" colname="type"></colspec>
5591 <colspec colwidth="9*" colname="description"></colspec>
5595 <entry>Description</entry>
5600 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5602 Use attribute (1). Common use attributes are
5603 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5604 62 Subject, 1003 Author), 1016 Any. Specify value
5609 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5611 Relation attribute (2). Common values are
5612 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5613 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5617 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5619 Position attribute (3). Values: 1 first in field, 2
5620 first in any subfield, 3 any position in field.
5624 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5626 Structure attribute (4). Values: 1 phrase, 2 word,
5627 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5628 101 name (norm), 102 name (un), 103 structure, 104 urx,
5629 105 free-form-text, 106 document-text, 107 local-number,
5630 108 string, 109 numeric string.
5634 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5636 Truncation attribute (5). Values: 1 right, 2 left,
5637 3 left& right, 100 none, 101 process #, 102 regular-1,
5638 103 regular-2, 104 CCL.
5642 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5644 Completeness attribute (6). Values: 1 incomplete subfield,
5645 2 complete subfield, 3 complete field.
5653 Refer to <xref linkend="bib1"/> or the complete
5654 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5657 It is also possible to specify non-numeric attribute values,
5658 which are used in combination with certain types.
5659 The special combinations are:
5660 <table id="ccl.special.attribute.combos">
5661 <title>Special attribute combos</title>
5663 <colspec colwidth="2*" colname="name"></colspec>
5664 <colspec colwidth="9*" colname="description"></colspec>
5668 <entry>Description</entry>
5673 <entry><literal>s=pw</literal></entry>
5675 The structure is set to either word or phrase depending
5676 on the number of tokens in a term (phrase-word).
5680 <entry><literal>s=al</literal></entry>
5682 Each token in the term is ANDed. (and-list).
5683 This does not set the structure at all.
5686 <row><entry><literal>s=ol</literal></entry>
5688 Each token in the term is ORed. (or-list).
5689 This does not set the structure at all.
5692 <row><entry><literal>s=ag</literal></entry>
5694 Tokens that appears as phrases (with blank in them) gets
5695 structure phrase attached (4=1). Tokens that appear to be words
5696 gets structure word attached (4=2). Phrases and words are
5697 ANDed. This is a variant of s=al and s=pw, with the main
5698 difference that words are not split (with operator AND)
5699 but instead kept in one RPN token. This facility appeared
5703 <row><entry><literal>r=o</literal></entry>
5705 Allows ranges and the operators greather-than, less-than, ...
5707 This sets Bib-1 relation attribute accordingly (relation
5708 ordered). A query construct is only treated as a range if
5709 dash is used and that is surrounded by white-space. So
5710 <literal>-1980</literal> is treated as term
5711 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5712 If <literal>- 1980</literal> is used, however, that is
5716 <row><entry><literal>r=r</literal></entry>
5718 Similar to <literal>r=o</literal> but assumes that terms
5719 are non-negative (not prefixed with <literal>-</literal>).
5720 Thus, a dash will always be treated as a range.
5721 The construct <literal>1980-1990</literal> is
5722 treated as a range with <literal>r=r</literal> but as a
5723 single term <literal>"1980-1990"</literal> with
5724 <literal>r=o</literal>. The special attribute
5725 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5728 <row><entry><literal>r=omiteq</literal></entry>
5730 This will omit relation=equals (@attr 2=3) when r=o / r=r
5731 is used. This is useful for servers that somehow breaks
5732 when an explicit relation=equals is used. Omitting the
5733 relation is usually safe because "equals" is the default
5734 behavior. This tweak was added in YAZ version 5.1.2.
5737 <row><entry><literal>t=l</literal></entry>
5739 Allows term to be left-truncated.
5740 If term is of the form <literal>?x</literal>, the resulting
5741 Type-1 term is <literal>x</literal> and truncation is left.
5744 <row><entry><literal>t=r</literal></entry>
5746 Allows term to be right-truncated.
5747 If term is of the form <literal>x?</literal>, the resulting
5748 Type-1 term is <literal>x</literal> and truncation is right.
5751 <row><entry><literal>t=n</literal></entry>
5753 If term is does not include <literal>?</literal>, the
5754 truncation attribute is set to none (100).
5757 <row><entry><literal>t=b</literal></entry>
5759 Allows term to be both left&right truncated.
5760 If term is of the form <literal>?x?</literal>, the
5761 resulting term is <literal>x</literal> and trunctation is
5762 set to both left&right.
5765 <row><entry><literal>t=x</literal></entry>
5767 Allows masking anywhere in a term, thus fully supporting
5768 # (mask one character) and ? (zero or more of any).
5769 If masking is used, trunction is set to 102 (regexp-1 in term)
5770 and the term is converted accordingly to a regular expression.
5773 <row><entry><literal>t=z</literal></entry>
5775 Allows masking anywhere in a term, thus fully supporting
5776 # (mask one character) and ? (zero or more of any).
5777 If masking is used, trunction is set to 104 (Z39.58 in term)
5778 and the term is converted accordingly to Z39.58 masking term -
5779 actually the same truncation as CCL itself.
5786 <example id="example.ccl.profile">
5787 <title>CCL profile</title>
5789 Consider the following definition:
5799 <literal>ti</literal> and <literal>au</literal> both set
5800 structure attribute to phrase (s=1).
5801 <literal>ti</literal>
5802 sets the use-attribute to 4. <literal>au</literal> sets the
5804 When no qualifiers are used in the query the structure-attribute is
5805 set to free-form-text (105) (rule for <literal>term</literal>).
5806 The <literal>date</literal> sets the relation attribute to
5807 the relation used in the CCL query and sets the use attribute
5811 You can combine attributes. To Search for "ranked title" you
5814 ti,ranked=knuth computer
5816 which will set relation=ranked, use=title, structure=phrase.
5823 is a valid query. But
5831 <sect4 id="ccl.qualifier.alias">
5832 <title>Qualifier alias</title>
5834 A qualifier alias is of the form:
5837 <replaceable>q</replaceable>
5838 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
5841 which declares <replaceable>q</replaceable> to
5842 be an alias for <replaceable>q1</replaceable>,
5843 <replaceable>q2</replaceable>... such that the CCL
5844 query <replaceable>q=x</replaceable> is equivalent to
5845 <replaceable>q1=x or q2=x or ...</replaceable>.
5848 <sect4 id="ccl.comments">
5849 <title>Comments</title>
5851 Lines with white space or lines that begin with
5852 character <literal>#</literal> are treated as comments.
5855 <sect4 id="ccl.directives">
5856 <title>Directives</title>
5858 Directive specifications takes the form
5860 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
5862 <table id="ccl.directives.table">
5863 <title>CCL directives</title>
5865 <colspec colwidth="2*" colname="name"></colspec>
5866 <colspec colwidth="8*" colname="description"></colspec>
5867 <colspec colwidth="1*" colname="default"></colspec>
5871 <entry>Description</entry>
5872 <entry>Default</entry>
5877 <entry>truncation</entry>
5878 <entry>Truncation character</entry>
5879 <entry><literal>?</literal></entry>
5883 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
5884 <entry><literal>#</literal></entry>
5887 <entry>field</entry>
5888 <entry>Specifies how multiple fields are to be
5889 combined. There are two modes: <literal>or</literal>:
5890 multiple qualifier fields are ORed,
5891 <literal>merge</literal>: attributes for the qualifier
5892 fields are merged and assigned to one term.
5894 <entry><literal>merge</literal></entry>
5898 <entry>Specifies if CCL operators and qualifiers should be
5899 compared with case sensitivity or not. Specify 1 for
5900 case sensitive; 0 for case insensitive.</entry>
5901 <entry><literal>1</literal></entry>
5905 <entry>Specifies token for CCL operator AND.</entry>
5906 <entry><literal>and</literal></entry>
5910 <entry>Specifies token for CCL operator OR.</entry>
5911 <entry><literal>or</literal></entry>
5915 <entry>Specifies token for CCL operator NOT.</entry>
5916 <entry><literal>not</literal></entry>
5920 <entry>Specifies token for CCL operator SET.</entry>
5921 <entry><literal>set</literal></entry>
5928 <sect3 id="ccl.api">
5929 <title>CCL API</title>
5931 All public definitions can be found in the header file
5932 <filename>ccl.h</filename>. A profile identifier is of type
5933 <literal>CCL_bibset</literal>. A profile must be created with the call
5934 to the function <function>ccl_qual_mk</function> which returns a profile
5935 handle of type <literal>CCL_bibset</literal>.
5938 To read a file containing qualifier definitions the function
5939 <function>ccl_qual_file</function> may be convenient. This function
5940 takes an already opened <literal>FILE</literal> handle pointer as
5941 argument along with a <literal>CCL_bibset</literal> handle.
5944 To parse a simple string with a FIND query use the function
5947 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
5948 int *error, int *pos);
5951 which takes the CCL profile (<literal>bibset</literal>) and query
5952 (<literal>str</literal>) as input. Upon successful completion the RPN
5953 tree is returned. If an error occur, such as a syntax error, the integer
5954 pointed to by <literal>error</literal> holds the error code and
5955 <literal>pos</literal> holds the offset inside query string in which
5959 An English representation of the error may be obtained by calling
5960 the <literal>ccl_err_msg</literal> function. The error codes are
5961 listed in <filename>ccl.h</filename>.
5964 To convert the CCL RPN tree (type
5965 <literal>struct ccl_rpn_node *</literal>)
5966 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
5967 must be used. This function which is part of YAZ is implemented in
5968 <filename>yaz-ccl.c</filename>.
5969 After calling this function the CCL RPN tree is probably no longer
5970 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
5973 A CCL profile may be destroyed by calling the
5974 <function>ccl_qual_rm</function> function.
5977 The token names for the CCL operators may be changed by setting the
5978 globals (all type <literal>char *</literal>)
5979 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
5980 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
5981 An operator may have aliases, i.e. there may be more than one name for
5982 the operator. To do this, separate each alias with a space character.
5989 <ulink url="&url.cql;">CQL</ulink>
5990 - Common Query Language - was defined for the
5991 <ulink url="&url.sru;">SRU</ulink> protocol.
5992 In many ways CQL has a similar syntax to CCL.
5993 The objective of CQL is different. Where CCL aims to be
5994 an end-user language, CQL is <emphasis>the</emphasis> protocol
5995 query language for SRU.
5999 If you are new to CQL, read the
6000 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6004 The CQL parser in &yaz; provides the following:
6008 It parses and validates a CQL query.
6013 It generates a C structure that allows you to convert
6014 a CQL query to some other query language, such as SQL.
6019 The parser converts a valid CQL query to PQF, thus providing a
6020 way to use CQL for both SRU servers and Z39.50 targets at the
6026 The parser converts CQL to XCQL.
6027 XCQL is an XML representation of CQL.
6028 XCQL is part of the SRU specification. However, since SRU
6029 supports CQL only, we don't expect XCQL to be widely used.
6030 Furthermore, CQL has the advantage over XCQL that it is
6036 <sect3 id="cql.parsing">
6037 <title>CQL parsing</title>
6039 A CQL parser is represented by the <literal>CQL_parser</literal>
6040 handle. Its contents should be considered &yaz; internal (private).
6042 #include <yaz/cql.h>
6044 typedef struct cql_parser *CQL_parser;
6046 CQL_parser cql_parser_create(void);
6047 void cql_parser_destroy(CQL_parser cp);
6049 A parser is created by <function>cql_parser_create</function> and
6050 is destroyed by <function>cql_parser_destroy</function>.
6053 To parse a CQL query string, the following function
6056 int cql_parser_string(CQL_parser cp, const char *str);
6058 A CQL query is parsed by the <function>cql_parser_string</function>
6059 which takes a query <parameter>str</parameter>.
6060 If the query was valid (no syntax errors), then zero is returned;
6061 otherwise -1 is returned to indicate a syntax error.
6065 int cql_parser_stream(CQL_parser cp,
6066 int (*getbyte)(void *client_data),
6067 void (*ungetbyte)(int b, void *client_data),
6070 int cql_parser_stdio(CQL_parser cp, FILE *f);
6072 The functions <function>cql_parser_stream</function> and
6073 <function>cql_parser_stdio</function> parses a CQL query
6074 - just like <function>cql_parser_string</function>.
6075 The only difference is that the CQL query can be
6076 fed to the parser in different ways.
6077 The <function>cql_parser_stream</function> uses a generic
6078 byte stream as input. The <function>cql_parser_stdio</function>
6079 uses a <literal>FILE</literal> handle which is opened for reading.
6082 <sect3 id="cql.tree">
6083 <title>CQL tree</title>
6085 The the query string is valid, the CQL parser
6086 generates a tree representing the structure of the
6091 struct cql_node *cql_parser_result(CQL_parser cp);
6093 <function>cql_parser_result</function> returns the
6094 a pointer to the root node of the resulting tree.
6097 Each node in a CQL tree is represented by a
6098 <literal>struct cql_node</literal>.
6099 It is defined as follows:
6101 #define CQL_NODE_ST 1
6102 #define CQL_NODE_BOOL 2
6103 #define CQL_NODE_SORT 3
6113 struct cql_node *modifiers;
6117 struct cql_node *left;
6118 struct cql_node *right;
6119 struct cql_node *modifiers;
6123 struct cql_node *next;
6124 struct cql_node *modifiers;
6125 struct cql_node *search;
6130 There are three node types: search term (ST), boolean (BOOL)
6132 A modifier is treated as a search term too.
6135 The search term node has five members:
6139 <literal>index</literal>: index for search term.
6140 If an index is unspecified for a search term,
6141 <literal>index</literal> will be NULL.
6146 <literal>index_uri</literal>: index URi for search term
6147 or NULL if none could be resolved for the index.
6152 <literal>term</literal>: the search term itself.
6157 <literal>relation</literal>: relation for search term.
6162 <literal>relation_uri</literal>: relation URI for search term.
6167 <literal>modifiers</literal>: relation modifiers for search
6168 term. The <literal>modifiers</literal> list itself of cql_nodes
6169 each of type <literal>ST</literal>.
6175 The boolean node represents <literal>and</literal>,
6176 <literal>or</literal>, <literal>not</literal> +
6181 <literal>left</literal> and <literal>right</literal>: left
6182 - and right operand respectively.
6187 <literal>modifiers</literal>: proximity arguments.
6193 The sort node represents both the SORTBY clause.
6196 <sect3 id="cql.to.pqf">
6197 <title>CQL to PQF conversion</title>
6199 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6200 that the resulting RPN depends on the Z39.50 target
6201 capabilities (combinations of supported attributes).
6202 In addition, the CQL and SRU operates on index prefixes
6203 (URI or strings), whereas the RPN uses Object Identifiers
6207 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6208 type. It represents a particular mapping between CQL and RPN.
6209 This handle is created and destroyed by the functions:
6211 cql_transform_t cql_transform_open_FILE (FILE *f);
6212 cql_transform_t cql_transform_open_fname(const char *fname);
6213 void cql_transform_close(cql_transform_t ct);
6215 The first two functions create a tranformation handle from
6216 either an already open FILE or from a filename respectively.
6219 The handle is destroyed by <function>cql_transform_close</function>
6220 in which case no further reference of the handle is allowed.
6223 When a <literal>cql_transform_t</literal> handle has been created
6224 you can convert to RPN.
6226 int cql_transform_buf(cql_transform_t ct,
6227 struct cql_node *cn, char *out, int max);
6229 This function converts the CQL tree <literal>cn</literal>
6230 using handle <literal>ct</literal>.
6231 For the resulting PQF, you supply a buffer <literal>out</literal>
6232 which must be able to hold at at least <literal>max</literal>
6236 If conversion failed, <function>cql_transform_buf</function>
6237 returns a non-zero SRU error code; otherwise zero is returned
6238 (conversion successful). The meanings of the numeric error
6239 codes are listed in the SRU specification somewhere (no
6240 direct link anymore).
6243 If conversion fails, more information can be obtained by calling
6245 int cql_transform_error(cql_transform_t ct, char **addinfop);
6247 This function returns the most recently returned numeric
6248 error-code and sets the string-pointer at
6249 <literal>*addinfop</literal> to point to a string containing
6250 additional information about the error that occurred: for
6251 example, if the error code is 15 (``Illegal or unsupported context
6252 set''), the additional information is the name of the requested
6253 context set that was not recognised.
6256 The SRU error-codes may be translated into brief human-readable
6257 error messages using
6259 const char *cql_strerror(int code);
6263 If you wish to be able to produce a PQF result in a different
6264 way, there are two alternatives.
6266 void cql_transform_pr(cql_transform_t ct,
6267 struct cql_node *cn,
6268 void (*pr)(const char *buf, void *client_data),
6271 int cql_transform_FILE(cql_transform_t ct,
6272 struct cql_node *cn, FILE *f);
6274 The former function produces output to a user-defined
6275 output stream. The latter writes the result to an already
6276 open <literal>FILE</literal>.
6279 <sect3 id="cql.to.rpn">
6280 <title>Specification of CQL to RPN mappings</title>
6282 The file supplied to functions
6283 <function>cql_transform_open_FILE</function>,
6284 <function>cql_transform_open_fname</function> follows
6285 a structure found in many Unix utilities.
6286 It consists of mapping specifications - one per line.
6287 Lines starting with <literal>#</literal> are ignored (comments).
6290 Each line is of the form
6292 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6296 An RPN pattern is a simple attribute list. Each attribute pair
6299 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6301 The attribute <replaceable>set</replaceable> is optional.
6302 The <replaceable>type</replaceable> is the attribute type,
6303 <replaceable>value</replaceable> the attribute value.
6306 The character <literal>*</literal> (asterisk) has special meaning
6307 when used in the RPN pattern.
6308 Each occurrence of <literal>*</literal> is substituted with the
6309 CQL matching name (index, relation, qualifier etc).
6310 This facility can be used to copy a CQL name verbatim to the RPN result.
6313 The following CQL patterns are recognized:
6317 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6321 This pattern is invoked when a CQL index, such as
6322 dc.title is converted. <replaceable>set</replaceable>
6323 and <replaceable>name</replaceable> are the context set and index
6325 Typically, the RPN specifies an equivalent use attribute.
6328 For terms not bound by an index the pattern
6329 <literal>index.cql.serverChoice</literal> is used.
6330 Here, the prefix <literal>cql</literal> is defined as
6331 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6332 If this pattern is not defined, the mapping will fail.
6336 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6337 is used when no other index pattern is matched.
6343 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6348 For backwards compatibility, this is recognised as a synonym of
6349 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6355 <literal>relation.</literal><replaceable>relation</replaceable>
6359 This pattern specifies how a CQL relation is mapped to RPN.
6360 <replaceable>pattern</replaceable> is name of relation
6361 operator. Since <literal>=</literal> is used as
6362 separator between CQL pattern and RPN, CQL relations
6363 including <literal>=</literal> cannot be
6364 used directly. To avoid a conflict, the names
6365 <literal>ge</literal>,
6366 <literal>eq</literal>,
6367 <literal>le</literal>,
6368 must be used for CQL operators, greater-than-or-equal,
6369 equal, less-than-or-equal respectively.
6370 The RPN pattern is supposed to include a relation attribute.
6373 For terms not bound by a relation, the pattern
6374 <literal>relation.scr</literal> is used. If the pattern
6375 is not defined, the mapping will fail.
6378 The special pattern, <literal>relation.*</literal> is used
6379 when no other relation pattern is matched.
6385 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6389 This pattern specifies how a CQL relation modifier is mapped to RPN.
6390 The RPN pattern is usually a relation attribute.
6396 <literal>structure.</literal><replaceable>type</replaceable>
6400 This pattern specifies how a CQL structure is mapped to RPN.
6401 Note that this CQL pattern is somewhat to similar to
6402 CQL pattern <literal>relation</literal>.
6403 The <replaceable>type</replaceable> is a CQL relation.
6406 The pattern, <literal>structure.*</literal> is used
6407 when no other structure pattern is matched.
6408 Usually, the RPN equivalent specifies a structure attribute.
6414 <literal>position.</literal><replaceable>type</replaceable>
6418 This pattern specifies how the anchor (position) of
6419 CQL is mapped to RPN.
6420 The <replaceable>type</replaceable> is one
6421 of <literal>first</literal>, <literal>any</literal>,
6422 <literal>last</literal>, <literal>firstAndLast</literal>.
6425 The pattern, <literal>position.*</literal> is used
6426 when no other position pattern is matched.
6432 <literal>set.</literal><replaceable>prefix</replaceable>
6436 This specification defines a CQL context set for a given prefix.
6437 The value on the right hand side is the URI for the set -
6438 <emphasis>not</emphasis> RPN. All prefixes used in
6439 index patterns must be defined this way.
6445 <literal>set</literal>
6449 This specification defines a default CQL context set for index names.
6450 The value on the right hand side is the URI for the set.
6456 <example id="example.cql.to.rpn.mapping">
6457 <title>CQL to RPN mapping file</title>
6459 This simple file defines two context sets, three indexes and three
6460 relations, a position pattern and a default structure.
6462 <programlisting><![CDATA[
6463 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6464 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6466 index.cql.serverChoice = 1=1016
6467 index.dc.title = 1=4
6468 index.dc.subject = 1=21
6474 position.any = 3=3 6=1
6480 With the mappings above, the CQL query
6484 is converted to the PQF:
6486 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6488 by rules <literal>index.cql.serverChoice</literal>,
6489 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6490 <literal>position.any</literal>.
6497 is rejected, since <literal>position.right</literal> is
6503 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6507 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6511 <example id="example.cql.to.rpn.string">
6512 <title>CQL to RPN string attributes</title>
6514 In this example we allow any index to be passed to RPN as
6517 <programlisting><![CDATA[
6518 # Identifiers for prefixes used in this file. (index.*)
6519 set.cql = info:srw/cql-context-set/1/cql-v1.1
6520 set.rpn = http://bogus/rpn
6521 set = http://bogus/rpn
6523 # The default index when none is specified by the query
6524 index.cql.serverChoice = 1=any
6533 The <literal>http://bogus/rpn</literal> context set is also the default
6534 so we can make queries such as
6538 which is converted to
6540 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6544 <example id="example.cql.to.rpn.bathprofile">
6545 <title>CQL to RPN using Bath Profile</title>
6547 The file <filename>etc/pqf.properties</filename> has mappings from
6548 the Bath Profile and Dublin Core to RPN.
6549 If YAZ is installed as a package it's usually located
6550 in <filename>/usr/share/yaz/etc</filename> and part of the
6551 development package, such as <literal>libyaz-dev</literal>.
6555 <sect3 id="cql.xcql">
6556 <title>CQL to XCQL conversion</title>
6558 Conversion from CQL to XCQL is trivial and does not
6559 require a mapping to be defined.
6560 There three functions to choose from depending on the
6561 way you wish to store the resulting output (XML buffer
6564 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6565 void cql_to_xml(struct cql_node *cn,
6566 void (*pr)(const char *buf, void *client_data),
6568 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6570 Function <function>cql_to_xml_buf</function> converts
6571 to XCQL and stores result in a user supplied buffer of a given
6575 <function>cql_to_xml</function> writes the result in
6576 a user defined output stream.
6577 <function>cql_to_xml_stdio</function> writes to a
6581 <sect3 id="rpn.to.cql">
6582 <title>PQF to CQL conversion</title>
6584 Conversion from PQF to CQL is offered by the two functions shown
6585 below. The former uses a generic stream for result. The latter
6586 puts result in a WRBUF (string container).
6588 #include <yaz/rpn2cql.h>
6590 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6591 void (*pr)(const char *buf, void *client_data),
6595 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6599 The configuration is the same as used in CQL to PQF conversions.
6604 <sect1 id="tools.oid">
6605 <title>Object Identifiers</title>
6607 The basic YAZ representation of an OID is an array of integers,
6608 terminated with the value -1. This integer is of type
6609 <literal>Odr_oid</literal>.
6612 Fundamental OID operations and the type <literal>Odr_oid</literal>
6613 are defined in <filename>yaz/oid_util.h</filename>.
6616 An OID can either be declared as a automatic variable or it can
6617 allocated using the memory utilities or ODR/NMEM. It's
6618 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6620 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6622 We can create an OID for the Bib-1 attribute set with:
6624 Odr_oid bib1[OID_SIZE];
6636 And OID may also be filled from a string-based representation using
6637 dots (.). This is achieved by function
6639 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6641 This functions returns 0 if name could be converted; -1 otherwise.
6643 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6645 We can fill the Bib-1 attribute set OID easier with:
6647 Odr_oid bib1[OID_SIZE];
6648 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6653 We can also allocate an OID dynamically on a ODR stream with:
6655 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6657 This creates an OID from string-based representation using dots.
6658 This function take an &odr; stream as parameter. This stream is used to
6659 allocate memory for the data elements, which is released on a
6660 subsequent call to <function>odr_reset()</function> on that stream.
6662 <example id="tools.oid.bib1.3">
6663 <title>Using odr_getoidbystr</title>
6665 We can create a OID for the Bib-1 attribute set with:
6667 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6674 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6676 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6677 converts an OID to the string-based representation using dots.
6678 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6679 string and must be at least <literal>OID_STR_MAX</literal> in size.
6682 OIDs can be copied with <function>oid_oidcpy</function> which takes
6683 two OID lists as arguments. Alternativly, an OID copy can be allocated
6684 on a ODR stream with:
6686 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6690 OIDs can be compared with <function>oid_oidcmp</function> which returns
6691 zero if the two OIDs provided are identical; non-zero otherwise.
6693 <sect2 id="tools.oid.database">
6694 <title>OID database</title>
6696 From YAZ version 3 and later, the oident system has been replaced
6697 by an OID database. OID database is a misnomer .. the old odient
6698 system was also a database.
6701 The OID database is really just a map between named Object Identifiers
6702 (string) and their OID raw equivalents. Most operations either
6703 convert from string to OID or other way around.
6706 Unfortunately, whenever we supply a string we must also specify the
6707 <emphasis>OID class</emphasis>. The class is necessary because some
6708 strings correspond to multiple OIDs. An example of such a string is
6709 <literal>Bib-1</literal> which may either be an attribute-set
6710 or a diagnostic-set.
6713 Applications using the YAZ database should include
6714 <filename>yaz/oid_db.h</filename>.
6717 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6718 Actually that's a pointer. You need not think deal with that.
6719 YAZ has a built-in database which can be considered "constant" for
6721 We can get hold that by using function <function>yaz_oid_std</function>.
6724 All functions with prefix <function>yaz_string_to_oid</function>
6725 converts from class + string to OID. We have variants of this
6726 operation due to different memory allocation strategies.
6729 All functions with prefix
6730 <function>yaz_oid_to_string</function> converts from OID to string
6733 <example id="tools.oid.bib1.4">
6734 <title>Create OID with YAZ DB</title>
6736 We can create an OID for the Bib-1 attribute set on the ODR stream
6740 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6742 This is more complex than using <function>odr_getoidbystr</function>.
6743 You would only use <function>yaz_string_to_oid_odr</function> when the
6744 string (here Bib-1) is supplied by a user or configuration.
6748 <sect2 id="tools.oid.std">
6749 <title>Standard OIDs</title>
6751 All the object identifers in the standard OID database as returned
6752 by <function>yaz_oid_std</function> can referenced directly in a
6753 program as a constant OID.
6754 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6755 followed by OID class (lowercase) - then by OID name (normalized and
6759 See <xref linkend="list-oids"/> for list of all object identifiers
6761 These are declared in <filename>yaz/oid_std.h</filename> but are
6762 included by <filename>yaz/oid_db.h</filename> as well.
6764 <example id="tools.oid.bib1.5">
6765 <title>Use a built-in OID</title>
6767 We can allocate our own OID filled with the constant OID for
6770 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6776 <sect1 id="tools.nmem">
6777 <title>Nibble Memory</title>
6779 Sometimes when you need to allocate and construct a large,
6780 interconnected complex of structures, it can be a bit of a pain to
6781 release the associated memory again. For the structures describing the
6782 Z39.50 PDUs and related structures, it is convenient to use the
6783 memory-management system of the &odr; subsystem (see
6784 <xref linkend="odr.use"/>). However, in some circumstances
6785 where you might otherwise benefit from using a simple nibble memory
6786 management system, it may be impractical to use
6787 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6788 For this purpose, the memory manager which also supports the &odr;
6789 streams is made available in the NMEM module. The external interface
6790 to this module is given in the <filename>nmem.h</filename> file.
6793 The following prototypes are given:
6796 NMEM nmem_create(void);
6797 void nmem_destroy(NMEM n);
6798 void *nmem_malloc(NMEM n, size_t size);
6799 void nmem_reset(NMEM n);
6800 size_t nmem_total(NMEM n);
6801 void nmem_init(void);
6802 void nmem_exit(void);
6805 The <function>nmem_create()</function> function returns a pointer to a
6806 memory control handle, which can be released again by
6807 <function>nmem_destroy()</function> when no longer needed.
6808 The function <function>nmem_malloc()</function> allocates a block of
6809 memory of the requested size. A call to <function>nmem_reset()</function>
6810 or <function>nmem_destroy()</function> will release all memory allocated
6811 on the handle since it was created (or since the last call to
6812 <function>nmem_reset()</function>. The function
6813 <function>nmem_total()</function> returns the number of bytes currently
6814 allocated on the handle.
6817 The nibble memory pool is shared amongst threads. POSIX
6818 mutex'es and WIN32 Critical sections are introduced to keep the
6819 module thread safe. Function <function>nmem_init()</function>
6820 initializes the nibble memory library and it is called automatically
6821 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6822 function <function>DllMain</function> to achieve this. You should
6823 <emphasis>not</emphasis> call <function>nmem_init</function> or
6824 <function>nmem_exit</function> unless you're absolute sure what
6825 you're doing. Note that in previous &yaz; versions you'd have to call
6826 <function>nmem_init</function> yourself.
6829 <sect1 id="tools.log">
6832 &yaz; has evolved a fairly complex log system which should be useful both
6833 for debugging &yaz; itself, debugging applications that use &yaz;, and for
6834 production use of those applications.
6837 The log functions are declared in header <filename>yaz/log.h</filename>
6838 and implemented in <filename>src/log.c</filename>.
6839 Due to name clash with syslog and some math utilities the logging
6840 interface has been modified as of YAZ 2.0.29. The obsolete interface
6841 is still available if in header file <filename>yaz/log.h</filename>.
6842 The key points of the interface are:
6845 void yaz_log(int level, const char *fmt, ...)
6846 void yaz_log_init(int level, const char *prefix, const char *name);
6847 void yaz_log_init_file(const char *fname);
6848 void yaz_log_init_level(int level);
6849 void yaz_log_init_prefix(const char *prefix);
6850 void yaz_log_time_format(const char *fmt);
6851 void yaz_log_init_max_size(int mx);
6853 int yaz_log_mask_str(const char *str);
6854 int yaz_log_module_level(const char *name);
6857 The reason for the whole log module is the <function>yaz_log</function>
6858 function. It takes a bitmask indicating the log levels, a
6859 <literal>printf</literal>-like format string, and a variable number of
6863 The <literal>log level</literal> is a bit mask, that says on which level(s)
6864 the log entry should be made, and optionally set some behaviour of the
6865 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
6866 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
6867 that modify the way the log entry is written:<literal>YLOG_ERRNO,
6868 YLOG_NOTIME, YLOG_FLUSH</literal>.
6869 Most of the rest of the bits are deprecated, and should not be used. Use
6870 the dynamic log levels instead.
6873 Applications that use &yaz;, should not use the LOG_LOG for ordinary
6874 messages, but should make use of the dynamic loglevel system. This consists
6875 of two parts, defining the loglevel and checking it.
6878 To define the log levels, the (main) program should pass a string to
6879 <function>yaz_log_mask_str</function> to define which log levels are to be
6880 logged. This string should be a comma-separated list of log level names,
6881 and can contain both hard-coded names and dynamic ones. The log level
6882 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
6883 for each word it meets, unless the word starts with a '-', in which case it
6884 clears the bit. If the string <literal>'none'</literal> is found,
6885 all bits are cleared. Typically this string comes from the command-line,
6886 often identified by <literal>-v</literal>. The
6887 <function>yaz_log_mask_str</function> returns a log level that should be
6888 passed to <function>yaz_log_init_level</function> for it to take effect.
6891 Each module should check what log bits it should be used, by calling
6892 <function>yaz_log_module_level</function> with a suitable name for the
6893 module. The name is cleared from a preceding path and an extension, if any,
6894 so it is quite possible to use <literal>__FILE__</literal> for it. If the
6895 name has been passed to <function>yaz_log_mask_str</function>, the routine
6896 returns a non-zero bitmask, which should then be used in consequent calls
6897 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
6898 yaz_log, in time-critical places, or when the log entry would take time
6902 Yaz uses the following dynamic log levels:
6903 <literal>server, session, request, requestdetail</literal> for the server
6905 <literal>zoom</literal> for the zoom client api.
6906 <literal>ztest</literal> for the simple test server.
6907 <literal>malloc, nmem, odr, eventl</literal> for internal
6908 debugging of yaz itself.
6909 Of course, any program using yaz is welcome to define as many new
6913 By default the log is written to stderr, but this can be changed by a call
6914 to <function>yaz_log_init_file</function> or
6915 <function>yaz_log_init</function>. If the log is directed to a file, the
6916 file size is checked at every write, and if it exceeds the limit given in
6917 <function>yaz_log_init_max_size</function>, the log is rotated. The
6918 rotation keeps one old version (with a <literal>.1</literal> appended to
6919 the name). The size defaults to 1GB. Setting it to zero will disable the
6923 A typical yaz-log looks like this
6924 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
6925 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
6926 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
6927 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
6928 13:24:13-23/11 yaz-ztest(1) [request] Close OK
6931 The log entries start with a time stamp. This can be omitted by setting the
6932 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
6933 can be hoped to produce identical log files, that are easy to diff. The
6934 format of the time stamp can be set with
6935 <function>yaz_log_time_format</function>, which takes a format string just
6936 like <function>strftime</function>.
6939 Next in a log line comes the prefix, often the name of the program. For
6940 yaz-based servers, it can also contain the session number. Then
6941 comes one or more logbits in square brackets, depending on the logging
6942 level set by <function>yaz_log_init_level</function> and the loglevel
6943 passed to <function>yaz_log_init_level</function>. Finally comes the format
6944 string and additional values passed to <function>yaz_log</function>
6947 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
6948 <literal>loglevel</literal>, will log all the log-level affecting
6949 operations. This can come in handy if you need to know what other log
6950 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
6953 The log system is almost independent of the rest of &yaz;, the only
6954 important dependence is of <filename>nmem</filename>, and that only for
6955 using the semaphore definition there.
6958 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
6959 the same time, the log bit names were changed from
6960 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
6961 to avoid collision with <filename>syslog.h</filename>.
6967 YAZ provides a fast utility for working with MARC records.
6968 Early versions of the MARC utility only allowed decoding of ISO2709.
6969 Today the utility may both encode - and decode to a varity of formats.
6972 #include <yaz/marcdisp.h>
6974 /* create handler */
6975 yaz_marc_t yaz_marc_create(void);
6977 void yaz_marc_destroy(yaz_marc_t mt);
6979 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
6980 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
6981 #define YAZ_MARC_LINE 0
6982 #define YAZ_MARC_SIMPLEXML 1
6983 #define YAZ_MARC_OAIMARC 2
6984 #define YAZ_MARC_MARCXML 3
6985 #define YAZ_MARC_ISO2709 4
6986 #define YAZ_MARC_XCHANGE 5
6987 #define YAZ_MARC_CHECK 6
6988 #define YAZ_MARC_TURBOMARC 7
6989 #define YAZ_MARC_JSON 8
6991 /* supply iconv handle for character set conversion .. */
6992 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
6994 /* set debug level, 0=none, 1=more, 2=even more, .. */
6995 void yaz_marc_debug(yaz_marc_t mt, int level);
6997 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
6998 On success, result in *result with size *rsize. */
6999 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7000 const char **result, size_t *rsize);
7002 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7003 On success, result in WRBUF */
7004 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7005 int bsize, WRBUF wrbuf);
7010 The synopsis is just a basic subset of all functionality. Refer
7011 to the actual header file <filename>marcdisp.h</filename> for
7016 A MARC conversion handle must be created by using
7017 <function>yaz_marc_create</function> and destroyed
7018 by calling <function>yaz_marc_destroy</function>.
7021 All other function operate on a <literal>yaz_marc_t</literal> handle.
7022 The output is specified by a call to <function>yaz_marc_xml</function>.
7023 The <literal>xmlmode</literal> must be one of
7026 <term>YAZ_MARC_LINE</term>
7029 A simple line-by-line format suitable for display but not
7030 recommend for further (machine) processing.
7035 <term>YAZ_MARC_MARCXML</term>
7038 <ulink url="&url.marcxml;">MARCXML</ulink>.
7043 <term>YAZ_MARC_ISO2709</term>
7046 ISO2709 (sometimes just referred to as "MARC").
7051 <term>YAZ_MARC_XCHANGE</term>
7054 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7059 <term>YAZ_MARC_CHECK</term>
7062 Pseudo format for validation only. Does not generate
7063 any real output except diagnostics.
7068 <term>YAZ_MARC_TURBOMARC</term>
7071 XML format with same semantics as MARCXML but more compact
7072 and geared towards fast processing with XSLT. Refer to
7073 <xref linkend="tools.turbomarc"/> for more information.
7078 <term>YAZ_MARC_JSON</term>
7081 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7088 The actual conversion functions are
7089 <function>yaz_marc_decode_buf</function> and
7090 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7091 a MARC record. The former function operates on simple buffers, the
7092 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7095 <example id="example.marc.display">
7096 <title>Display of MARC record</title>
7098 The following program snippet illustrates how the MARC API may
7099 be used to convert a MARC record to the line-by-line format:
7100 <programlisting><![CDATA[
7101 void print_marc(const char *marc_buf, int marc_buf_size)
7103 char *result; /* for result buf */
7104 size_t result_len; /* for size of result */
7105 yaz_marc_t mt = yaz_marc_create();
7106 yaz_marc_xml(mt, YAZ_MARC_LINE);
7107 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7108 &result, &result_len);
7109 fwrite(result, result_len, 1, stdout);
7110 yaz_marc_destroy(mt); /* note that result is now freed... */
7116 <sect2 id="tools.turbomarc">
7117 <title>TurboMARC</title>
7119 TurboMARC is yet another XML encoding of a MARC record. The format
7120 was designed for fast processing with XSLT.
7124 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7125 representation. This conversion mostly check the tag of a MARC field
7126 to determine the basic rules in the conversion. This check is
7127 costly when that is tag is encoded as an attribute in MARCXML.
7128 By having the tag value as the element instead, makes processing
7129 many times faster (at least for Libxslt).
7132 TurboMARC is encoded as follows:
7136 Record elements is part of namespace
7137 "<literal>http://www.indexdata.com/turbomarc</literal>".
7142 A record is enclosed in element <literal>r</literal>.
7147 A collection of records is enclosed in element
7148 <literal>collection</literal>.
7153 The leader is encoded as element <literal>l</literal> with the
7154 leader content as its (text) value.
7159 A control field is encoded as element <literal>c</literal> concatenated
7160 with the tag value of the control field if the tag value
7161 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7162 If the tag value do not match the regular expression
7163 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7164 as element <literal>c</literal> and attribute <literal>code</literal>
7165 will hold the tag value.
7166 This rule ensure that in the rare cases where a tag value might
7167 result in a non-wellformed XML YAZ encode it as a coded attribute
7171 The control field content is the the text value of this element.
7172 Indicators are encoded as attribute names
7173 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7174 corresponding values for each indicator.
7179 A data field is encoded as element <literal>d</literal> concatenated
7180 with the tag value of the data field or using the attribute
7181 <literal>code</literal> as described in the rules for control fields.
7182 The children of the data field element is subfield elements.
7183 Each subfield element is encoded as <literal>s</literal>
7184 concatenated with the sub field code.
7185 The text of the subfield element is the contents of the subfield.
7186 Indicators are encoded as attributes for the data field element similar
7187 to the encoding for control fields.
7194 <sect1 id="tools.retrieval">
7195 <title>Retrieval Facility</title>
7197 YAZ version 2.1.20 or later includes a Retrieval facility tool
7198 which allows a SRU/Z39.50 to describe itself and perform record
7199 conversions. The idea is the following:
7203 An SRU/Z39.50 client sends a retrieval request which includes
7204 a combination of the following parameters: syntax (format),
7205 schema (or element set name).
7210 The retrieval facility is invoked with parameters in a
7211 server/proxy. The retrieval facility matches the parameters a set of
7212 "supported" retrieval types.
7213 If there is no match, the retrieval signals an error
7214 (syntax and / or schema not supported).
7219 For a successful match, the backend is invoked with the same
7220 or altered retrieval parameters (syntax, schema). If
7221 a record is received from the backend, it is converted to the
7222 frontend name / syntax.
7227 The resulting record is sent back the client and tagged with
7228 the frontend syntax / schema.
7234 The Retrieval facility is driven by an XML configuration. The
7235 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7236 should be easy to generate both of them from the XML configuration.
7237 (unfortunately the two versions
7238 of ZeeRex differ substantially in this regard).
7240 <sect2 id="tools.retrieval.format">
7241 <title>Retrieval XML format</title>
7243 All elements should be covered by namespace
7244 <literal>http://indexdata.com/yaz</literal> .
7245 The root element node must be <literal>retrievalinfo</literal>.
7248 The <literal>retrievalinfo</literal> must include one or
7249 more <literal>retrieval</literal> elements. Each
7250 <literal>retrieval</literal> defines specific combination of
7251 syntax, name and identifier supported by this retrieval service.
7254 The <literal>retrieval</literal> element may include any of the
7255 following attributes:
7257 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7260 Defines the record syntax. Possible values is any
7261 of the names defined in YAZ' OID database or a raw
7266 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7269 Defines the name of the retrieval format. This can be
7270 any string. For SRU, the value, is equivalent to schema (short-hand);
7271 for Z39.50 it's equivalent to simple element set name.
7272 For YAZ 3.0.24 and later this name may be specified as a glob
7273 expression with operators
7274 <literal>*</literal> and <literal>?</literal>.
7278 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7281 Defines the URI schema name of the retrieval format. This can be
7282 any string. For SRU, the value, is equivalent to URI schema.
7283 For Z39.50, there is no equivalent.
7290 The <literal>retrieval</literal> may include one
7291 <literal>backend</literal> element. If a <literal>backend</literal>
7292 element is given, it specifies how the records are retrieved by
7293 some backend and how the records are converted from the backend to
7297 The attributes, <literal>name</literal> and <literal>syntax</literal>
7298 may be specified for the <literal>backend</literal> element. These
7299 semantics of these attributes is equivalent to those for the
7300 <literal>retrieval</literal>. However, these values are passed to
7304 The <literal>backend</literal> element may includes one or more
7305 conversion instructions (as children elements). The supported
7308 <varlistentry><term><literal>marc</literal></term>
7311 The <literal>marc</literal> element specifies a conversion
7312 to - and from ISO2709 encoded MARC and
7313 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7314 The following attributes may be specified:
7317 <term><literal>inputformat</literal> (REQUIRED)</term>
7320 Format of input. Supported values are
7321 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7322 (MARCXML/MarcXchange) and <literal>json</literal>
7323 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7328 <term><literal>outputformat</literal> (REQUIRED)</term>
7331 Format of output. Supported values are
7332 <literal>line</literal> (MARC line format);
7333 <literal>marcxml</literal> (for MARCXML),
7334 <literal>marc</literal> (ISO2709),
7335 <literal>marcxhcange</literal> (for MarcXchange),
7336 or <literal>json</literal>
7337 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7342 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7345 Encoding of input. For XML input formats, this need not
7346 be given, but for ISO2709 based inputformats, this should
7347 be set to the encoding used. For MARC21 records, a common
7348 inputcharset value would be <literal>marc-8</literal>.
7353 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7356 Encoding of output. If outputformat is XML based, it is
7357 strongly recommened to use <literal>utf-8</literal>.
7366 <term><literal>xslt</literal></term>
7369 The <literal>xslt</literal> element specifies a conversion
7370 via &acro.xslt;. The following attributes may be specified:
7372 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7384 <term><literal>solrmarc</literal></term>
7387 The <literal>solrmarc</literal> decodes solrmarc records.
7388 It assumes that the input is pure solrmarc text (no escaping)
7389 and will convert all sequences of the form #XX; to a single
7390 character of the hexadecimal value as given by XX. The output,
7391 presumably, is a valid ISO2709 buffer.
7394 This conversion is available in YAZ 5.0.21 and later.
7401 <sect2 id="tools.retrieval.examples">
7402 <title>Retrieval Facility Examples</title>
7403 <example id="tools.retrieval.marc21">
7404 <title>MARC21 backend</title>
7406 A typical way to use the retrieval facility is to enable XML
7407 for servers that only supports ISO2709 encoded MARC21 records.
7409 <programlisting><![CDATA[
7411 <retrieval syntax="usmarc" name="F"/>
7412 <retrieval syntax="usmarc" name="B"/>
7413 <retrieval syntax="xml" name="marcxml"
7414 identifier="info:srw/schema/1/marcxml-v1.1">
7415 <backend syntax="usmarc" name="F">
7416 <marc inputformat="marc" outputformat="marcxml"
7417 inputcharset="marc-8"/>
7420 <retrieval syntax="xml" name="dc">
7421 <backend syntax="usmarc" name="F">
7422 <marc inputformat="marc" outputformat="marcxml"
7423 inputcharset="marc-8"/>
7424 <xslt stylesheet="MARC21slim2DC.xsl"/>
7431 This means that our frontend supports:
7435 MARC21 F(ull) records.
7440 MARC21 B(rief) records.
7450 Dublin core records.
7456 <example id="tools.retrieval.marcxml">
7457 <title>MARCXML backend</title>
7459 SRW/SRU and Solr backends returns records in XML.
7460 If they return MARCXML or MarcXchange, the retrieval module
7461 can convert those into ISO2709 formats, most commonly USMARC
7463 In this example, the backend returns MARCXML for schema="marcxml".
7465 <programlisting><![CDATA[
7467 <retrieval syntax="usmarc">
7468 <backend syntax="xml" name="marcxml">
7469 <marc inputformat="xml" outputformat="marc"
7470 outputcharset="marc-8"/>
7473 <retrieval syntax="xml" name="marcxml"
7474 identifier="info:srw/schema/1/marcxml-v1.1"/>
7475 <retrieval syntax="xml" name="dc">
7476 <backend syntax="xml" name="marcxml">
7477 <xslt stylesheet="MARC21slim2DC.xsl"/>
7484 This means that our frontend supports:
7488 MARC21 records (any element set name) in MARC-8 encoding.
7493 MARCXML records for element-set=marcxml
7498 Dublin core records for element-set=dc.
7505 <sect2 id="tools.retrieval.api">
7508 It should be easy to use the retrieval systems from applications. Refer
7510 <filename>yaz/retrieval.h</filename> and
7511 <filename>yaz/record_conv.h</filename>.
7515 <sect1 id="sorting">
7516 <title>Sorting</title>
7518 This chapter describes sorting and how it is supported in YAZ.
7519 Sorting applies to a result-set.
7521 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7522 Z39.50 sorting facility
7524 takes one or more input result-sets
7525 and one result-set as output. The most simple case is that
7526 the input-set is the same as the output-set.
7529 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7530 following a search (two phases).
7533 In SRU/Solr, however, the model is different. Here, sorting is specified
7534 during the the search operation. Note, however, that SRU might
7535 perform sort as separate search, by referring to an existing result-set
7536 in the query (result-set reference).
7539 <title>Using the Z39.50 sort service</title>
7541 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7542 case the sort sequence or sort critiera is using a string notation.
7543 This notation is a one-line notation suitable for being manually
7544 entered or generated and allows for easy logging (one liner).
7545 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7546 function. For yaz-client the sort is performed and specified using
7547 the sort and sort+ commands. For description of the sort criteria notation
7548 refer to the <link linkend="sortspec">sort command</link> in the
7552 The ZOOM API might choose one of several sort strategies for
7553 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7557 <title>Type-7 sort</title>
7559 Type-7 sort is an extension to the Bib-1 based RPN query where the
7560 sort specification is embedded as an Attribute-Plus-Term.
7563 The objectives for introducing Type-7 sorting is that it allows
7564 a client to perform sorting even if it does not implement/support
7565 Z39.50 sort. Virtually all Z39.50 client software supports
7566 RPN queries. It also may improve performance because the sort
7567 critieria is specified along with the search query.
7570 The sort is triggered by the presence of type 7 and the value of type 7
7572 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7575 The value for type 7 is 1 for ascending and 2 for descending.
7577 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7580 only the generic part is handled. If generic sortKey is of type
7581 sortField, then attribute type 1 is present and the value is
7582 sortField (InternationalString). If generic sortKey is of type
7583 sortAttributes, then the attributes in list is used . generic sortKey
7584 of type elementSpec is not supported.
7587 The term in the sorting Attribute-Plus-Term combo should hold
7588 an integer. The value is 0 for primary sorting criteria, 1 for second
7594 <title>Facets</title>
7596 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7599 Like Type-1/RPN, YAZ supports a string notation for specifying
7600 facets. For the API this is performed by
7601 <function>yaz_pqf_parse_facet_list</function>.
7604 For ZOOM C the facets are given by option "facets"
7605 For yaz-client it is used for the facets command.
7608 The grammar of this specification is as follows:
7610 facet-spec ::= facet-list
7612 facet-list ::= facet-list ',' attr-spec | attr-spec
7614 attr-spec ::= attr-spec '@attr' string | '@attr' string
7617 The notation is inspired by PQF. The string following '@attr'
7618 may not include blanks and is of the form
7619 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7620 where <replaceable>type</replaceable> is an integer and
7621 <replaceable>value</replaceable> is a string or an integer.
7624 The Facets specification is not Bib-1. The following types apply:
7626 <table id="facet.attributes">
7627 <title>Facet attributes</title>
7629 <colspec colwidth="2*" colname="type"></colspec>
7630 <colspec colwidth="9*" colname="description"></colspec>
7634 <entry>Description</entry>
7641 Field-name. This is often a string, eg "Author", "Year", etc.
7647 Sort order. Value should be an integer.
7648 Value 0: count descending (frequency). Value 1: alpha ascending.
7654 Number of terms requested.
7669 <title>The ODR Module</title>
7670 <sect1 id="odr.introduction">
7671 <title>Introduction</title>
7673 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7674 to isolate &odr; from the rest of the package - specifically from the
7675 transport interface. &odr; may be used in any context where basic
7676 ASN.1/BER representations are used.
7679 If you are only interested in writing a Z39.50 implementation based on
7680 the PDUs that are already provided with &yaz;, you only need to concern
7681 yourself with the section on managing ODR streams
7682 (<xref linkend="odr.use"/>). Only if you need to
7683 implement ASN.1 beyond that which has been provided, should you
7684 worry about the second half of the documentation
7685 (<xref linkend="odr.programming"/>).
7686 If you use one of the higher-level interfaces, you can skip this
7690 This is important, so we'll repeat it for emphasis: <emphasis>You do
7691 not need to read <xref linkend="odr.programming"/>
7692 to implement Z39.50 with &yaz;.</emphasis>
7695 If you need a part of the protocol that isn't already in &yaz;, you
7696 should contact the authors before going to work on it yourself: We
7697 might already be working on it. Conversely, if you implement a useful
7698 part of the protocol before us, we'd be happy to include it in a
7702 <sect1 id="odr.use">
7703 <title>Using ODR</title>
7704 <sect2 id="odr.streams">
7705 <title>ODR Streams</title>
7707 Conceptually, the ODR stream is the source of encoded data in the
7708 decoding mode; when encoding, it is the receptacle for the encoded
7709 data. Before you can use an ODR stream it must be allocated. This is
7710 done with the function
7713 ODR odr_createmem(int direction);
7716 The <function>odr_createmem()</function> function takes as argument one
7717 of three manifest constants: <literal>ODR_ENCODE</literal>,
7718 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7719 An &odr; stream can be in only one mode - it is not possible to change
7720 its mode once it's selected. Typically, your program will allocate
7721 at least two ODR streams - one for decoding, and one for encoding.
7724 When you're done with the stream, you can use
7727 void odr_destroy(ODR o);
7730 to release the resources allocated for the stream.
7733 <sect2 id="odr.memory.management">
7734 <title id="memory">Memory Management</title>
7736 Two forms of memory management take place in the &odr; system. The first
7737 one, which has to do with allocating little bits of memory (sometimes
7738 quite large bits of memory, actually) when a protocol package is
7739 decoded, and turned into a complex of interlinked structures. This
7740 section deals with this system, and how you can use it for your own
7741 purposes. The next section deals with the memory management which is
7742 required when encoding data - to make sure that a large enough buffer is
7743 available to hold the fully encoded PDU.
7746 The &odr; module has its own memory management system, which is
7747 used whenever memory is required. Specifically, it is used to allocate
7748 space for data when decoding incoming PDUs. You can use the memory
7749 system for your own purposes, by using the function
7752 void *odr_malloc(ODR o, size_t size);
7755 You can't use the normal <function>free(2)</function> routine to free
7756 memory allocated by this function, and &odr; doesn't provide a parallel
7757 function. Instead, you can call
7760 void odr_reset(ODR o);
7763 when you are done with the
7764 memory: Everything allocated since the last call to
7765 <function>odr_reset()</function> is released.
7766 The <function>odr_reset()</function> call is also required to clear
7767 up an error condition on a stream.
7773 size_t odr_total(ODR o);
7776 returns the number of bytes allocated on the stream since the last call to
7777 <function>odr_reset()</function>.
7780 The memory subsystem of &odr; is fairly efficient at allocating and
7781 releasing little bits of memory. Rather than managing the individual,
7782 small bits of space, the system maintains a free-list of larger chunks
7783 of memory, which are handed out in small bits. This scheme is
7784 generally known as a <emphasis>nibble memory</emphasis> system.
7785 It is very useful for maintaining short-lived constructions such
7789 If you want to retain a bit of memory beyond the next call to
7790 <function>odr_reset()</function>, you can use the function
7793 ODR_MEM odr_extract_mem(ODR o);
7796 This function will give you control of the memory recently allocated
7797 on the ODR stream. The memory will live (past calls to
7798 <function>odr_reset()</function>), until you call the function
7801 void odr_release_mem(ODR_MEM p);
7804 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
7805 referencing the memory block for you until you want to release it.
7808 You can use <function>odr_extract_mem()</function> repeatedly between
7809 allocating data, to retain individual control of separate chunks of data.
7812 <sect2 id="odr.encoding.and.decoding">
7813 <title>Encoding and Decoding Data</title>
7815 When encoding data, the ODR stream will write the encoded octet string
7816 in an internal buffer. To retrieve the data, use the function
7819 char *odr_getbuf(ODR o, int *len, int *size);
7822 The integer pointed to by len is set to the length of the encoded
7823 data, and a pointer to that data is returned. <literal>*size</literal>
7824 is set to the size of the buffer (unless <literal>size</literal> is null,
7825 signaling that you are not interested in the size). The next call to
7826 a primitive function using the same &odr; stream will overwrite the
7827 data, unless a different buffer has been supplied using the call
7830 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
7833 which sets the encoding (or decoding) buffer used by
7834 <literal>o</literal> to <literal>buf</literal>, using the length
7835 <literal>len</literal>.
7836 Before a call to an encoding function, you can use
7837 <function>odr_setbuf()</function> to provide the stream with an encoding
7838 buffer of sufficient size (length). The <literal>can_grow</literal>
7839 parameter tells the encoding &odr; stream whether it is allowed to use
7840 <function>realloc(2)</function> to increase the size of the buffer when
7841 necessary. The default condition of a new encoding stream is equivalent
7842 to the results of calling
7845 odr_setbuf(stream, 0, 0, 1);
7848 In this case, the stream will allocate and reallocate memory as
7849 necessary. The stream reallocates memory by repeatedly doubling the
7850 size of the buffer - the result is that the buffer will typically
7851 reach its maximum, working size with only a small number of reallocation
7852 operations. The memory is freed by the stream when the latter is destroyed,
7853 unless it was assigned by the user with the <literal>can_grow</literal>
7854 parameter set to zero (in this case, you are expected to retain
7855 control of the memory yourself).
7858 To assume full control of an encoded buffer, you must first call
7859 <function>odr_getbuf()</function> to fetch the buffer and its length.
7860 Next, you should call <function>odr_setbuf()</function> to provide a
7861 different buffer (or a null pointer) to the stream. In the simplest
7862 case, you will reuse the same buffer over and over again, and you
7863 will just need to call <function>odr_getbuf()</function> after each
7864 encoding operation to get the length and address of the buffer.
7865 Note that the stream may reallocate the buffer during an encoding
7866 operation, so it is necessary to retrieve the correct address after
7867 each encoding operation.
7870 It is important to realize that the ODR stream will not release this
7871 memory when you call <function>odr_reset()</function>: It will
7872 merely update its internal pointers to prepare for the encoding of a
7874 When the stream is released by the <function>odr_destroy()</function>
7875 function, the memory given to it by <function>odr_setbuf</function> will
7876 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
7877 parameter to <function>odr_setbuf()</function> was nonzero. The
7878 <literal>can_grow</literal> parameter, in other words, is a way of
7879 signaling who is to own the buffer, you or the ODR stream. If you never call
7880 <function>odr_setbuf()</function> on your encoding stream, which is
7881 typically the case, the buffer allocated by the stream will belong to
7882 the stream by default.
7885 When you wish to decode data, you should first call
7886 <function>odr_setbuf()</function>, to tell the decoding stream
7887 where to find the encoded data, and how long the buffer is
7888 (the <literal>can_grow</literal> parameter is ignored by a decoding
7889 stream). After this, you can call the function corresponding to the
7890 data you wish to decode (eg, <function>odr_integer()</function> odr
7891 <function>z_APDU()</function>).
7893 <example id="example.odr.encoding.and.decoding.functions">
7894 <title>Encoding and decoding functions</title>
7896 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
7898 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
7902 If the data is absent (or doesn't match the tag corresponding to
7903 the type), the return value will be either 0 or 1 depending on the
7904 <literal>optional</literal> flag. If <literal>optional</literal>
7905 is 0 and the data is absent, an error flag will be raised in the
7906 stream, and you'll need to call <function>odr_reset()</function> before
7907 you can use the stream again. If <literal>optional</literal> is
7908 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
7909 <literal>p</literal> will be set to the null value, and the function
7911 The <literal>name</literal> argument is used to pretty-print the
7912 tag in question. It may be set to <literal>NULL</literal> if
7913 pretty-printing is not desired.
7916 If the data value is found where it's expected, the pointer
7917 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
7918 will be set to point to the decoded type.
7919 The space for the type will be allocated and owned by the &odr;
7920 stream, and it will live until you call
7921 <function>odr_reset()</function> on the stream. You cannot use
7922 <function>free(2)</function> to release the memory.
7923 You can decode several data elements (by repeated calls to
7924 <function>odr_setbuf()</function> and your decoding function), and
7925 new memory will be allocated each time. When you do call
7926 <function>odr_reset()</function>, everything decoded since the
7927 last call to <function>odr_reset()</function> will be released.
7929 <example id="example.odr.encoding.of.integer">
7930 <title>Encoding and decoding of an integer</title>
7932 The use of the double indirection can be a little confusing at first
7933 (its purpose will become clear later on, hopefully),
7934 so an example is in order. We'll encode an integer value, and
7935 immediately decode it again using a different stream. A useless, but
7936 informative operation.
7938 <programlisting><![CDATA[
7939 void do_nothing_useful(Odr_int value)
7942 Odr_int *valp, *resvalp;
7946 /* allocate streams */
7947 if (!(encode = odr_createmem(ODR_ENCODE)))
7949 if (!(decode = odr_createmem(ODR_DECODE)))
7953 if (odr_integer(encode, &valp, 0, 0) == 0)
7955 printf("encoding went bad\n");
7958 bufferp = odr_getbuf(encode, &len, 0);
7959 printf("length of encoded data is %d\n", len);
7961 /* now let's decode the thing again */
7962 odr_setbuf(decode, bufferp, len, 0);
7963 if (odr_integer(decode, &resvalp, 0, 0) == 0)
7965 printf("decoding went bad\n");
7968 /* ODR_INT_PRINTF format for printf (such as %d) */
7969 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
7972 odr_destroy(encode);
7973 odr_destroy(decode);
7978 This looks like a lot of work, offhand. In practice, the &odr; streams
7979 will typically be allocated once, in the beginning of your program
7980 (or at the beginning of a new network session), and the encoding
7981 and decoding will only take place in a few, isolated places in your
7982 program, so the overhead is quite manageable.
7986 <sect2 id="odr.printing">
7987 <title>Printing</title>
7989 When an ODR stream is created of type <literal>ODR_PRINT</literal>
7990 the ODR module will print the contents of a PDU in a readable format.
7991 By default output is written to the <literal>stderr</literal> stream.
7992 This behavior can be changed, however, by calling the function
7994 odr_setprint(ODR o, FILE *file);
7996 before encoders or decoders are being invoked.
7997 It is also possible to direct the output to a buffer (of indeed
7998 another file), by using the more generic mechanism:
8000 void odr_set_stream(ODR o, void *handle,
8001 void (*stream_write)(ODR o, void *handle, int type,
8002 const char *buf, int len),
8003 void (*stream_close)(void *handle));
8005 Here the user provides an opaque handle and two handlers,
8006 <replaceable>stream_write</replaceable> for writing,
8007 and <replaceable>stream_close</replaceable> which is supposed
8008 to close/free resources associated with handle.
8009 The <replaceable>stream_close</replaceable> handler is optional and
8010 if NULL for the function is provided, it will not be invoked.
8011 The <replaceable>stream_write</replaceable> takes the ODR handle
8012 as parameter, the user defined handle, a type
8013 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8014 which indicates the type of contents is being written.
8017 Another utility useful for diagnostics (error handling) or as
8018 part of the printing facilities is:
8020 const char **odr_get_element_path(ODR o);
8022 which returns a list of current elements that ODR deals with at the
8023 moment. For the returned array, say <literal>ar</literal>,
8024 <literal>ar[0]</literal> is the top level element,
8025 <literal>ar[n]</literal> is the last. The last element has the
8026 property that <literal>ar[n+1] == NULL</literal>.
8028 <example id="example.odr.element.path.record">
8029 <title>Element Path for record</title>
8031 For a database record part of a PresentResponse the
8032 array returned by <function>odr_get_element</function>
8033 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8034 unnamed constructions.
8038 <sect2 id="odr.diagnostics">
8039 <title>Diagnostics</title>
8041 The encoding/decoding functions all return 0 when an error occurs.
8042 Until you call <function>odr_reset()</function>, you cannot use the
8043 stream again, and any function called will immediately return 0.
8046 To provide information to the programmer or administrator, the function
8049 void odr_perror(ODR o, char *message);
8052 is provided, which prints the <literal>message</literal> argument to
8053 <literal>stderr</literal> along with an error message from the stream.
8056 You can also use the function
8059 int odr_geterror(ODR o);
8062 to get the current error number from the screen. The number will be
8063 one of these constants:
8065 <table frame="top" id="odr.error.codes">
8066 <title>ODR Error codes</title>
8071 <entry>Description</entry>
8076 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8079 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8080 The standard diagnostic variable <literal>errno</literal> should be
8081 examined to determine the actual error.</entry>
8084 <entry>OSPACE</entry><entry>No more space for encoding.
8085 This will only occur when the user has explicitly provided a
8086 buffer for an encoding stream without allowing the system to
8087 allocate more space.</entry>
8090 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8091 required data element was missing during encoding or decoding.</entry>
8094 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8095 found during decoding.</entry>
8098 <entry>OOTHER</entry><entry>Other error. This is typically an
8099 indication of misuse of the &odr; system by the programmer, and also
8100 that the diagnostic system isn't as good as it should be, yet.</entry>
8106 The character string array
8112 can be indexed by the error code to obtain a human-readable
8113 representation of the problem.
8116 <sect2 id="odr.summary.and.synopsis">
8117 <title>Summary and Synopsis</title>
8119 #include <yaz/odr.h>
8121 ODR odr_createmem(int direction);
8123 void odr_destroy(ODR o);
8125 void odr_reset(ODR o);
8127 char *odr_getbuf(ODR o, int *len, int *size);
8129 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8131 void *odr_malloc(ODR o, int size);
8133 NMEM odr_extract_mem(ODR o);
8135 int odr_geterror(ODR o);
8137 void odr_perror(ODR o, const char *message);
8139 extern char *odr_errlist[];
8143 <sect1 id="odr.programming">
8144 <title>Programming with ODR</title>
8146 The API of &odr; is designed to reflect the structure of ASN.1, rather
8147 than BER itself. Future releases may be able to represent data in
8148 other external forms.
8152 There is an ASN.1 tutorial available at
8153 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8154 This site also has standards for ASN.1 (X.680) and BER (X.690)
8155 <ulink url="&url.asn.1.standards;">online</ulink>.
8159 The ODR interface is based loosely on that of the Sun Microsystems
8161 Specifically, each function which corresponds to an ASN.1 primitive
8162 type has a dual function. Depending on the settings of the ODR
8163 stream which is supplied as a parameter, the function may be used
8164 either to encode or decode data. The functions that can be built
8165 using these primitive functions, to represent more complex data types,
8166 share this quality. The result is that you only have to enter the
8167 definition for a type once - and you have the functionality of encoding,
8168 decoding (and pretty-printing) all in one unit.
8169 The resulting C source code is quite compact, and is a pretty
8170 straightforward representation of the source ASN.1 specification.
8173 In many cases, the model of the XDR functions works quite well in this
8175 In others, it is less elegant. Most of the hassle comes from the optional
8176 SEQUENCE members which don't exist in XDR.
8178 <sect2 id="odr.primitive.asn1.types">
8179 <title>The Primitive ASN.1 Types</title>
8181 ASN.1 defines a number of primitive types (many of which correspond
8182 roughly to primitive types in structured programming languages, such as C).
8184 <sect3 id="odr.integer">
8185 <title>INTEGER</title>
8187 The &odr; function for encoding or decoding (or printing) the ASN.1
8188 INTEGER type looks like this:
8191 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8194 The <literal>Odr_int</literal> is just a simple integer.
8197 This form is typical of the primitive &odr; functions. They are named
8198 after the type of data that they encode or decode. They take an &odr;
8199 stream, an indirect reference to the type in question, and an
8200 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8201 of ASN.1) as parameters. They all return an integer value of either one
8203 When you use the primitive functions to construct encoders for complex
8204 types of your own, you should follow this model as well. This
8205 ensures that your new types can be reused as elements in yet more
8209 The <literal>o</literal> parameter should obviously refer to a properly
8210 initialized &odr; stream of the right type (encoding/decoding/printing)
8211 for the operation that you wish to perform.
8214 When encoding or printing, the function first looks at
8215 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8216 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8217 the data element is absent. If the <literal>optional</literal> parameter
8218 is nonzero, the function will return one (signifying success) without
8219 any further processing. If the <literal>optional</literal> is zero, an
8220 internal error flag is set in the &odr; stream, and the function will
8221 return 0. No further operations can be carried out on the stream without
8222 a call to the function <function>odr_reset()</function>.
8225 If <literal>*p</literal> is not a null pointer, it is expected to
8226 point to an instance of the data type. The data will be subjected to
8227 the encoding rules, and the result will be placed in the buffer held
8228 by the &odr; stream.
8231 The other ASN.1 primitives have similar functions that operate in
8235 <sect3 id="odr.boolean">
8236 <title>BOOLEAN</title>
8238 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8241 <sect3 id="odr.real">
8247 <sect3 id="odr.null">
8250 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8253 In this case, the value of **p is not important. If <literal>*p</literal>
8254 is different from the null pointer, the null value is present, otherwise
8258 <sect3 id="odr.octet.string">
8259 <title>OCTET STRING</title>
8261 typedef struct odr_oct
8267 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8271 The <literal>buf</literal> field should point to the character array
8272 that holds the octetstring. The <literal>len</literal> field holds the
8274 The character array need not be null terminated.
8277 To make things a little easier, an alternative is given for string
8278 types that are not expected to contain embedded NULL characters (eg.
8282 int odr_cstring(ODR o, char **p, int optional, const char *name);
8285 Which encoded or decodes between OCTETSTRING representations and
8286 null-terminates C strings.
8289 Functions are provided for the derived string types, eg:
8292 int odr_visiblestring(ODR o, char **p, int optional,
8296 <sect3 id="odr.bit.string">
8297 <title>BIT STRING</title>
8299 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8303 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8304 holding relatively brief bit strings, eg. for options fields, etc.
8305 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8306 gives the maximum possible number of bits.
8309 A set of macros are provided for manipulating the
8310 <literal>Odr_bitmask</literal> type:
8313 void ODR_MASK_ZERO(Odr_bitmask *b);
8315 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8317 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8319 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8322 The functions are modeled after the manipulation functions that
8323 accompany the <literal>fd_set</literal> type used by the
8324 <function>select(2)</function> call.
8325 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8326 new bitmask, to initialize the bits to zero.
8329 <sect3 id="odr.object.identifier">
8330 <title>OBJECT IDENTIFIER</title>
8332 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8335 The C OID representation is simply an array of integers, terminated by
8336 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8337 the <literal>short</literal> type).
8338 We suggest that you use the OID database module (see
8339 <xref linkend="tools.oid.database"/>) to handle object identifiers
8340 in your application.
8344 <sect2 id="odr.tagging.primitive.types">
8345 <title>Tagging Primitive Types</title>
8347 The simplest way of tagging a type is to use the
8348 <function>odr_implicit_tag()</function> or
8349 <function>odr_explicit_tag()</function> macros:
8352 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8353 int optional, const char *name);
8355 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8356 int optional, const char *name);
8359 To create a type derived from the integer type by implicit tagging, you
8363 MyInt ::= [210] IMPLICIT INTEGER
8366 In the &odr; system, this would be written like:
8369 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8371 return odr_implicit_tag(o, odr_integer, p,
8372 ODR_CONTEXT, 210, optional, name);
8376 The function <function>myInt()</function> can then be used like any of
8377 the primitive functions provided by &odr;. Note that the behavior of
8378 <function>odr_explicit_tag()</function>
8379 and <function>odr_implicit_tag()</function> macros
8380 act exactly the same as the functions they are applied to - they
8381 respond to error conditions, etc, in the same manner - they
8382 simply have three extra parameters. The class parameter may
8383 take one of the values: <literal>ODR_CONTEXT</literal>,
8384 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8385 <literal>/ODR_APPLICATION</literal>.
8388 <sect2 id="odr.constructed.types">
8389 <title>Constructed Types</title>
8391 Constructed types are created by combining primitive types. The
8392 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8393 (although adding the rest of the container types should be simple
8394 enough, if the need arises).
8397 For implementing SEQUENCEs, the functions
8400 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8401 int odr_sequence_end(ODR o);
8407 The <function>odr_sequence_begin()</function> function should be
8408 called in the beginning of a function that implements a SEQUENCE type.
8409 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8410 you're implementing), and the <literal>size</literal> of the type
8411 (typically a C structure). On encoding, it returns 1 if
8412 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8413 parameter is ignored. On decoding, it returns 1 if the type is found in
8414 the data stream. <literal>size</literal> bytes of memory are allocated,
8415 and <literal>*p</literal> is set to point to this space.
8416 <function>odr_sequence_end()</function> is called at the end of the
8417 complex function. Assume that a type is defined like this:
8420 MySequence ::= SEQUENCE {
8422 boolval BOOLEAN OPTIONAL
8426 The corresponding &odr; encoder/decoder function and the associated data
8427 structures could be written like this:
8430 typedef struct MySequence
8436 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8438 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8439 return optional && odr_ok(o);
8441 odr_integer(o, &(*p)->intval, 0, "intval") &&
8442 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8443 odr_sequence_end(o);
8447 Note the 1 in the call to <function>odr_bool()</function>, to mark
8448 that the sequence member is optional.
8449 If either of the member types had been tagged, the macros
8450 <function>odr_implicit_tag()</function> or
8451 <function>odr_explicit_tag()</function>
8452 could have been used.
8453 The new function can be used exactly like the standard functions provided
8454 with &odr;. It will encode, decode or pretty-print a data value of the
8455 <literal>MySequence</literal> type. We like to name types with an
8456 initial capital, as done in ASN.1 definitions, and to name the
8457 corresponding function with the first character of the name in lower case.
8458 You could, of course, name your structures, types, and functions any way
8459 you please - as long as you're consistent, and your code is easily readable.
8460 <literal>odr_ok</literal> is just that - a predicate that returns the
8461 state of the stream. It is used to ensure that the behavior of the new
8462 type is compatible with the interface of the primitive types.
8465 <sect2 id="odr.tagging.constructed.types">
8466 <title>Tagging Constructed Types</title>
8469 See <xref linkend="odr.tagging.primitive.types"/> for information
8470 on how to tag the primitive types, as well as types that are
8474 <sect3 id="odr.implicit.tagging">
8475 <title>Implicit Tagging</title>
8477 Assume the type above had been defined as
8480 MySequence ::= [10] IMPLICIT SEQUENCE {
8482 boolval BOOLEAN OPTIONAL
8486 You would implement this in &odr; by calling the function
8489 int odr_implicit_settag(ODR o, int class, int tag);
8492 which overrides the tag of the type immediately following it. The
8493 macro <function>odr_implicit_tag()</function> works by calling
8494 <function>odr_implicit_settag()</function> immediately
8495 before calling the function pointer argument.
8496 Your type function could look like this:
8499 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8501 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8502 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8503 return optional && odr_ok(o);
8505 odr_integer(o, &(*p)->intval, 0, "intval") &&
8506 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8507 odr_sequence_end(o);
8511 The definition of the structure <literal>MySequence</literal> would be
8515 <sect3 id="odr.explicit.tagging">
8516 <title>Explicit Tagging</title>
8518 Explicit tagging of constructed types is a little more complicated,
8519 since you are in effect adding a level of construction to the data.
8522 Assume the definition:
8525 MySequence ::= [10] IMPLICIT SEQUENCE {
8527 boolval BOOLEAN OPTIONAL
8531 Since the new type has an extra level of construction, two new functions
8532 are needed to encapsulate the base type:
8535 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8538 int odr_constructed_end(ODR o);
8541 Assume that the IMPLICIT in the type definition above were replaced
8542 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8543 would be equivalent). The structure definition would look the same,
8544 but the function would look like this:
8547 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8549 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8550 return optional && odr_ok(o);
8551 if (o->direction == ODR_DECODE)
8552 *p = odr_malloc(o, sizeof(**p));
8553 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8555 *p = 0; /* this is almost certainly a protocol error */
8559 odr_integer(o, &(*p)->intval, 0, "intval") &&
8560 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8561 odr_sequence_end(o) &&
8562 odr_constructed_end(o);
8566 Notice that the interface here gets kind of nasty. The reason is
8567 simple: Explicitly tagged, constructed types are fairly rare in
8568 the protocols that we care about, so the
8569 esthetic annoyance (not to mention the dangers of a cluttered
8570 interface) is less than the time that would be required to develop a
8571 better interface. Nevertheless, it is far from satisfying, and it's a
8572 point that will be worked on in the future. One option for you would
8573 be to simply apply the <function>odr_explicit_tag()</function> macro to
8574 the first function, and not
8575 have to worry about <function>odr_constructed_*</function> yourself.
8576 Incidentally, as you might have guessed, the
8577 <function>odr_sequence_</function> functions are themselves
8578 implemented using the <function>/odr_constructed_</function> functions.
8582 <sect2 id="odr.sequence.of">
8583 <title>SEQUENCE OF</title>
8585 To handle sequences (arrays) of a specific type, the function
8588 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8589 void *p, int *num, const char *name);
8592 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8593 function of the type. <literal>p</literal> is a pointer to an array of
8594 pointers to your type. <literal>num</literal> is the number of elements
8601 MyArray ::= SEQUENCE OF INTEGER
8604 The C representation might be
8607 typedef struct MyArray
8614 And the function might look like
8617 int myArray(ODR o, MyArray **p, int optional, const char *name)
8619 if (o->direction == ODR_DECODE)
8620 *p = odr_malloc(o, sizeof(**p));
8621 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8622 &(*p)->num_elements, name))
8625 return optional && odr_ok(o);
8629 <sect2 id="odr.choice.types">
8630 <title>CHOICE Types</title>
8632 The choice type is used fairly often in some ASN.1 definitions, so
8633 some work has gone into streamlining its interface.
8636 CHOICE types are handled by the function:
8639 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8643 The <literal>arm</literal> array is used to describe each of the possible
8644 types that the CHOICE type may assume. Internally in your application,
8645 the CHOICE type is represented as a discriminated union. That is, a
8646 C union accompanied by an integer (or enum) identifying the active
8648 <literal>whichp</literal> is a pointer to the union discriminator.
8649 When encoding, it is examined to determine the current type.
8650 When decoding, it is set to reference the type that was found in
8654 The Odr_arm type is defined thus:
8657 typedef struct odr_arm
8668 The interpretation of the fields are:
8672 <term>tagmode</term>
8673 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8674 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8675 to mark no tagging.</para></listitem>
8679 <listitem><para>The value of the discriminator that corresponds to
8680 this CHOICE element. Typically, it will be a #defined constant, or
8681 an enum member.</para></listitem>
8685 <listitem><para>A pointer to a function that implements the type of
8686 the CHOICE member. It may be either a standard &odr; type or a type
8687 defined by yourself.</para></listitem>
8691 <listitem><para>Name of tag.</para></listitem>
8695 A handy way to prepare the array for use by the
8696 <function>odr_choice()</function> function is to
8697 define it as a static, initialized array in the beginning of your
8698 decoding/encoding function. Assume the type definition:
8701 MyChoice ::= CHOICE {
8703 tagged [99] IMPLICIT INTEGER,
8708 Your C type might look like
8711 typedef struct MyChoice
8728 And your function could look like this:
8731 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8733 static Odr_arm arm[] =
8735 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8736 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8738 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8742 if (o->direction == ODR_DECODE)
8743 *p = odr_malloc(o, sizeof(**p);
8745 return optional && odr_ok(o);
8747 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8750 return optional && odr_ok(o);
8754 In some cases (say, a non-optional choice which is a member of a
8755 sequence), you can "embed" the union and its discriminator in the
8756 structure belonging to the enclosing type, and you won't need to
8757 fiddle with memory allocation to create a separate structure to
8758 wrap the discriminator and union.
8761 The corresponding function is somewhat nicer in the Sun XDR interface.
8762 Most of the complexity of this interface comes from the possibility of
8763 declaring sequence elements (including CHOICEs) optional.
8766 The ASN.1 specifications naturally requires that each member of a
8767 CHOICE have a distinct tag, so they can be told apart on decoding.
8768 Sometimes it can be useful to define a CHOICE that has multiple types
8769 that share the same tag. You'll need some other mechanism, perhaps
8770 keyed to the context of the CHOICE type. In effect, we would like to
8771 introduce a level of context-sensitiveness to our ASN.1 specification.
8772 When encoding an internal representation, we have no problem, as long
8773 as each CHOICE member has a distinct discriminator value. For
8774 decoding, we need a way to tell the choice function to look for a
8775 specific arm of the table. The function
8778 void odr_choice_bias(ODR o, int what);
8781 provides this functionality. When called, it leaves a notice for the next
8782 call to <function>odr_choice()</function> to be called on the decoding
8783 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8784 a <literal>which</literal> field equal to <literal>what</literal>
8788 The most important application (perhaps the only one, really) is in
8789 the definition of application-specific EXTERNAL encoders/decoders
8790 which will automatically decode an ANY member given the direct or
8795 <sect1 id="odr.debugging">
8796 <title>Debugging</title>
8798 The protocol modules are suffering somewhat from a lack of diagnostic
8799 tools at the moment. Specifically ways to pretty-print PDUs that
8800 aren't recognized by the system. We'll include something to this end
8801 in a not-too-distant release. In the meantime, what we do when we get
8802 packages we don't understand is to compile the ODR module with
8803 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
8804 information as it processes data units. With this output and the
8805 protocol specification (Z39.50), it is generally fairly easy to see
8810 <chapter id="comstack">
8811 <title>The COMSTACK Module</title>
8812 <sect1 id="comstack.synopsis">
8813 <title>Synopsis (blocking mode)</title>
8814 <programlisting><![CDATA[
8817 int size = 0, length_incoming;
8818 char server_address_str[] = "localhost:9999";
8819 void *server_address_ip;
8822 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
8823 int protocol_package_length = strlen(protocol_package);
8825 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
8827 perror("cs_create"); /* use perror() here since we have no stack yet */
8831 server_address_ip = cs_straddr(stack, server_address_str);
8832 if (!server_address_ip) {
8833 fprintf(stderr, "cs_straddr: address could not be resolved\n");
8837 status = cs_connect(stack, server_address_ip);
8839 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
8843 status = cs_rcvconnect(stack);
8845 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
8849 status = cs_put(stack, protocol_package, protocol_package_length);
8851 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
8855 /* Now get a response */
8856 length_incoming = cs_get(stack, &buf, &size);
8857 if (!length_incoming) {
8858 fprintf(stderr, "Connection closed\n");
8860 } else if (length_incoming < 0) {
8861 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
8866 fwrite(buf, length_incoming, 1, stdout);
8877 <sect1 id="comstack.introduction">
8878 <title>Introduction</title>
8881 subsystem provides a transparent interface to different types of transport
8882 stacks for the exchange of BER-encoded data and HTTP packets.
8883 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
8884 experimental SSL stack are supported, but others may be added in time.
8885 The philosophy of the
8886 module is to provide a simple interface by hiding unused options and
8887 facilities of the underlying libraries. This is always done at the risk
8888 of losing generality, and it may prove that the interface will need
8893 There hasn't been interest in the XTImOSI stack for some years.
8894 Therefore, it is no longer supported.
8898 The interface is implemented in such a fashion that only the
8899 sub-layers constructed to the transport methods that you wish to
8900 use in your application are linked in.
8903 You will note that even though simplicity was a goal in the design,
8904 the interface is still orders of magnitudes more complex than the
8905 transport systems found in many other packages. One reason is that
8906 the interface needs to support the somewhat different requirements of
8907 the different lower-layer communications stacks; another important
8908 reason is that the interface seeks to provide a more or less
8909 industrial-strength approach to asynchronous event-handling.
8910 When no function is allowed to block, things get more complex -
8911 particularly on the server side.
8912 We urge you to have a look at the demonstration client and server
8913 provided with the package. They are meant to be easily readable and
8914 instructive, while still being at least moderately useful.
8917 <sect1 id="comstack.common">
8918 <title>Common Functions</title>
8919 <sect2 id="comstack.managing.endpoints">
8920 <title>Managing Endpoints</title>
8922 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
8925 Creates an instance of the protocol stack - a communications endpoint.
8926 The <literal>type</literal> parameter determines the mode
8927 of communication. At present the following values are supported:
8931 <term><literal>tcpip_type</literal></term>
8932 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
8936 <term><literal>ssl_type</literal></term>
8937 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
8938 is experimental and is not fully implemented. If
8939 HTTP is used, this effectively is HTTPS.
8943 <term><literal>unix_type</literal></term>
8944 <listitem><para>Unix socket (unix only). Local Transfer via
8945 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
8946 <manvolnum>7</manvolnum></citerefentry>.
8951 The <function>cs_create</function> function returns a null-pointer
8952 if a system error occurs.
8953 The <literal>blocking</literal> parameter should be one if
8954 you wish the association to operate in blocking mode, zero otherwise.
8955 The <literal>protocol</literal> field should be
8956 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
8957 Protocol <literal>PROTO_SR</literal> is no longer supported.
8960 void cs_close(COMSTACK handle);
8963 Closes the connection (as elegantly as the lower layers will permit),
8964 and releases the resources pointed to by the
8965 <literal>handle</literal>
8967 <literal>handle</literal>
8968 should not be referenced again after this call.
8972 We really need a soft disconnect, don't we?
8976 <sect2 id="comstack.data.exchange">
8977 <title>Data Exchange</title>
8979 int cs_put(COMSTACK handle, char *buf, int len);
8982 Sends <literal>buf</literal> down the wire.
8983 In blocking mode, this function will return only when a full buffer has
8984 been written, or an error has occurred. In nonblocking mode, it's
8985 possible that the function will be unable to send the full buffer
8986 at once, which will be indicated by a return value of 1.
8987 The function will keep track of the number of octets already written; you
8988 should call it repeatedly with the same values of <literal>buf</literal>
8989 and <literal>len</literal>, until the buffer has been transmitted.
8990 When a full buffer has been sent, the function will return 0 for
8991 success. -1 indicates an error condition (see below).
8994 int cs_get(COMSTACK handle, char **buf, int *size);
8997 Receives a PDU or HTTP Response from the peer. Returns the number of
8999 In nonblocking mode, it is possible that not all of the packet can be
9000 read at once. In this case, the function returns 1. To simplify the
9001 interface, the function is
9002 responsible for managing the size of the buffer. It will be reallocated
9003 if necessary to contain large packages, and will sometimes be moved
9004 around internally by the subsystem when partial packages are read. Before
9006 <function>cs_get</function>
9007 for the fist time, the buffer can be initialized to the null pointer,
9008 and the length should also be set to 0 - cs_get will perform a
9009 <function>malloc(2)</function>
9010 on the buffer for you. When a full buffer has been read, the size of
9011 the package is returned (which will always be greater than 1). -1
9012 indicates an error condition.
9015 See also the <function>cs_more()</function> function below.
9018 int cs_more(COMSTACK handle);
9021 The <function>cs_more()</function> function should be used in conjunction
9022 with <function>cs_get</function> and
9023 <function>select(2)</function>.
9024 The <function>cs_get()</function> function will sometimes
9025 (notably in the TCP/IP mode) read more than a single protocol package
9026 off the network. When this happens, the extra package is stored
9027 by the subsystem. After calling <function>cs_get()</function>, and before
9028 waiting for more input, You should always call
9029 <function>cs_more()</function>
9030 to check if there's a full protocol package already read. If
9031 <function>cs_more()</function>
9033 <function>cs_get()</function>
9034 can be used to immediately fetch the new package. For the
9036 subsystem, the function should always return 0, but if you want your
9037 stuff to be protocol independent, you should use it.
9041 The <function>cs_more()</function>
9042 function is required because the RFC1729-method
9043 does not provide a way of separating individual PDUs, short of
9044 partially decoding the BER. Some other implementations will carefully
9045 nibble at the packet by calling
9046 <function>read(2)</function>
9047 several times. This was felt to be too inefficient (or at least
9048 clumsy) - hence the call for this extra function.
9052 int cs_look(COMSTACK handle);
9055 This function is useful when you're operating in nonblocking
9057 <function>select(2)</function>
9058 tells you there's something happening on the line. It returns one of
9059 the following values:
9063 <term>CS_NONE</term>
9065 No event is pending. The data found on the line was not a
9070 <term>CS_CONNECT</term>
9072 A response to your connect request has been received. Call
9073 <function>cs_rcvconnect</function>
9074 to process the event and to finalize the connection establishment.
9078 <term>CS_DISCON</term>
9080 The other side has closed the connection (or maybe sent a disconnect
9081 request - but do we care? Maybe later). Call
9082 <function>cs_close</function> to close your end of the association
9087 <term>CS_LISTEN</term>
9089 A connect request has been received.
9090 Call <function>cs_listen</function> to process the event.
9094 <term>CS_DATA</term>
9096 There's data to be found on the line.
9097 Call <function>cs_get</function> to get it.
9103 You should be aware that even if
9104 <function>cs_look()</function>
9105 tells you that there's an event event pending, the corresponding
9106 function may still return and tell you there was nothing to be found.
9107 This means that only part of a package was available for reading. The
9108 same event will show up again, when more data has arrived.
9112 int cs_fileno(COMSTACK h);
9115 Returns the file descriptor of the association. Use this when
9116 file-level operations on the endpoint are required
9117 (<function>select(2)</function> operations, specifically).
9121 <sect1 id="comstack.client">
9122 <title>Client Side</title>
9124 int cs_connect(COMSTACK handle, void *address);
9127 Initiate a connection with the target at <literal>address</literal>
9128 (more on addresses below). The function will return 0 on success, and 1 if
9129 the operation does not complete immediately (this will only
9130 happen on a nonblocking endpoint). In this case, use
9131 <function>cs_rcvconnect</function> to complete the operation,
9132 when <function>select(2)</function> or <function>poll(2)</function>
9133 reports input pending on the association.
9136 int cs_rcvconnect(COMSTACK handle);
9139 Complete a connect operation initiated by <function>cs_connect()</function>.
9140 It will return 0 on success; 1 if the operation has not yet completed (in
9141 this case, call the function again later); -1 if an error has occurred.
9144 <sect1 id="comstack.server">
9145 <title>Server Side</title>
9147 To establish a server under the <application>inetd</application>
9151 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9155 The <literal>socket</literal> parameter is an established socket (when
9156 your application is invoked from <application>inetd</application>, the
9157 socket will typically be 0.
9158 The following parameters are identical to the ones for
9159 <function>cs_create</function>.
9162 int cs_bind(COMSTACK handle, void *address, int mode)
9165 Binds a local address to the endpoint. Read about addresses below. The
9166 <literal>mode</literal> parameter should be either
9167 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9170 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9173 Call this to process incoming events on an endpoint that has been
9174 bound in listening mode. It will return 0 to indicate that the connect
9175 request has been received, 1 to signal a partial reception, and -1 to
9176 indicate an error condition.
9179 COMSTACK cs_accept(COMSTACK handle);
9182 This finalizes the server-side association establishment, after
9183 cs_listen has completed successfully. It returns a new connection
9184 endpoint, which represents the new association. The application will
9185 typically wish to fork off a process to handle the association at this
9186 point, and continue listen for new connections on the old
9187 <literal>handle</literal>.
9190 You can use the call
9193 const char *cs_addrstr(COMSTACK);
9196 on an established connection to retrieve the host-name of the remote host.
9200 You may need to use this function with some care if your
9201 name server service is slow or unreliable
9205 <sect1 id="comstack.addresses">
9206 <title>Addresses</title>
9208 The low-level format of the addresses are different depending on the
9209 mode of communication you have chosen. A function is provided by each
9210 of the lower layers to map a user-friendly string-form address to the
9211 binary form required by the lower layers.
9214 void *cs_straddr(COMSTACK handle, const char *str);
9217 The format for TCP/IP and SSL addresses is:
9220 <host> [ ':' <portnum> ]
9223 The <literal>hostname</literal> can be either a domain name or an
9224 IP address. The port number, if omitted, defaults to 210.
9227 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9228 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9229 IPV4 binding as well (bindv6only=0),
9230 The special hostname <literal>@4</literal> binds to
9231 <literal>INADDR_ANY</literal> (IPV4 only listener).
9232 The special hostname <literal>@6</literal> binds to
9233 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9236 For UNIX sockets, the format of an address is the socket filename.
9239 When a connection has been established, you can use
9242 const char *cs_addrstr(COMSTACK h);
9245 to retrieve the host name of the peer system. The function returns
9246 a pointer to a static area, which is overwritten on the next call
9250 A fairly recent addition to the &comstack; module is the utility
9254 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9257 which is just a wrapper for <function>cs_create</function> and
9258 <function>cs_straddr</function>. The <parameter>str</parameter>
9259 is similar to that described for <function>cs_straddr</function>
9260 but with a prefix denoting the &comstack; type. Prefixes supported
9261 are <literal>tcp:</literal>, <literal>unix:</literal> and
9262 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9263 If no prefix is given, then TCP/IP is used.
9264 The <parameter>blocking</parameter> is passed to
9265 function <function>cs_create</function>. The third parameter
9266 <parameter>vp</parameter> is a pointer to &comstack; stack type
9268 Parameter <parameter>vp</parameter> is reserved for future use.
9269 Set it to <literal>NULL</literal>.
9272 <sect1 id="comstack.ssl">
9276 void *cs_get_ssl(COMSTACK cs);
9278 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9279 is not of type SSL, NULL is returned.
9283 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9285 Sets SSL context for comstack. The parameter is expected to be of type
9286 <literal>SSL_CTX *</literal>. This function should be called just
9287 after comstack has been created (before connect, bind, etc).
9288 This function returns 1 for success; 0 for failure.
9292 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9294 Sets SSL certificate for comstack as a PEM file. This function
9295 returns 1 for success; 0 for failure.
9299 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9301 This function returns the peer certificate. If successful,
9302 <literal>*buf</literal> and <literal>*len</literal> holds
9303 X509 buffer and length respectively. Buffer should be freed
9304 with <literal>xfree</literal>. This function returns 1 for success;
9308 <sect1 id="comstack.diagnostics">
9309 <title>Diagnostics</title>
9311 All functions return -1 if an error occurs. Typically, the functions
9312 will return 0 on success, but the data exchange functions
9313 (<function>cs_get</function>, <function>cs_put</function>,
9314 <function>cs_more</function>) follow special rules. Consult their
9318 The error code for the COMSTACK can be retrieved using C macro
9319 <function>cs_errno</function> which will return one
9320 of the error codes <literal>CSYSERR</literal>,
9321 <literal>CSOUTSTATE</literal>,
9322 <literal>CSNODATA</literal>, ...
9325 int cs_errno(COMSTACK handle);
9328 You can the textual representation of the error code
9329 by using <function>cs_errmsg</function> - which
9330 works like <function>strerror(3)</function>
9333 const char *cs_errmsg(int n);
9336 It is also possible to get straight to the textual represenataion
9337 without the error code by using
9338 <function>cs_strerror</function>.
9341 const char *cs_strerror(COMSTACK h);
9344 <sect1 id="comstack.summary">
9345 <title>Summary and Synopsis</title>
9347 #include <yaz/comstack.h>
9349 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9350 #include <yaz/unix.h> /* this is for UNIX socket support */
9352 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9354 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9356 COMSTACK cs_create_host(const char *str, int blocking,
9359 int cs_bind(COMSTACK handle, int mode);
9361 int cs_connect(COMSTACK handle, void *address);
9363 int cs_rcvconnect(COMSTACK handle);
9365 int cs_listen(COMSTACK handle);
9367 COMSTACK cs_accept(COMSTACK handle);
9369 int cs_put(COMSTACK handle, char *buf, int len);
9371 int cs_get(COMSTACK handle, char **buf, int *size);
9373 int cs_more(COMSTACK handle);
9375 void cs_close(COMSTACK handle);
9377 int cs_look(COMSTACK handle);
9379 void *cs_straddr(COMSTACK handle, const char *str);
9381 const char *cs_addrstr(COMSTACK h);
9386 <chapter id="future">
9387 <title>Future Directions</title>
9389 We have a new and better version of the front-end server on the drawing
9390 board. Resources and external commitments will govern when we'll be
9391 able to do something real with it. Features should include greater
9392 flexibility, greater support for access/resource control, and easy
9393 support for Explain (possibly with Zebra as an extra database engine).
9396 &yaz; is a BER toolkit and as such should support all protocols
9397 out there based on that. We'd like to see running ILL applications.
9398 It shouldn't be that hard. Another thing that would be interesting is
9399 LDAP. Maybe a generic framework for doing IR using both LDAP and
9400 Z39.50 transparently.
9403 The SOAP implementation is incomplete. In the future we hope
9404 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9405 The authors of libxml2 are already working on XML Schema / RelaxNG
9406 compilers so this may not be too hard.
9409 It would be neat to have a proper module mechanism for the Generic
9410 Frontend Server so that backend would be dynamically
9411 loaded (as shared objects / DLLs).
9414 Other than that, &yaz; generally moves in the directions which appear to
9415 make the most people happy (including ourselves, as prime users of the
9416 software). If there's something you'd like to see in here, then drop
9417 us a note and let's see what we can come up with.
9420 <reference id="reference">
9421 <title>Reference</title>
9422 <partintro id="reference-introduction">
9424 The material in this chapter is drawn directly from the individual
9430 <appendix id="list-oids">
9431 <title>List of Object Identifiers</title>
9433 These is a list of object identifiers that are built into YAZ.
9437 <appendix id="bib1-diagnostics">
9438 <title>Bib-1 diagnostics</title>
9440 List of Bib-1 diagnostics that are known to YAZ.
9444 <appendix id="sru-diagnostics">
9445 <title>SRU diagnostics</title>
9447 List of SRU diagnostics that are known to YAZ.
9451 <appendix id="license">
9452 <title>License</title>
9453 <sect1 id="license.indexdata">
9454 <title>Index Data Copyright</title>
9456 Copyright © ©right-year; Index Data.
9459 All rights reserved.
9462 Redistribution and use in source and binary forms, with or without
9463 modification, are permitted provided that the following conditions are met:
9468 Redistributions of source code must retain the above copyright
9469 notice, this list of conditions and the following disclaimer.
9474 Redistributions in binary form must reproduce the above copyright
9475 notice, this list of conditions and the following disclaimer in the
9476 documentation and/or other materials provided with the distribution.
9481 Neither the name of Index Data nor the names of its contributors
9482 may be used to endorse or promote products derived from this
9483 software without specific prior written permission.
9488 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9489 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9490 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9491 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9492 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9493 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9494 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9495 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9496 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9497 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9502 <appendix id="indexdata">
9503 <title>About Index Data</title>
9505 Index Data is a consulting and software-development enterprise that
9506 specializes in library and information management systems. Our
9507 interests and expertise span a broad range of related fields, and one
9508 of our primary, long-term objectives is the development of a powerful
9509 information management
9510 system with open network interfaces and hyper-media capabilities.
9512 We make this software available free of charge, on a fairly unrestrictive
9513 license; as a service to the networking community, and to further the
9514 development of quality software for open network communication.
9516 We'll be happy to answer questions about the software, and about ourselves
9522 <street>Amagerfælledvej 56</street>
9523 <postcode>2300 Copenhagen S</postcode>
9524 <country>Denmark</country>
9525 Email <email>info@indexdata.dk</email>
9529 The Hacker's Jargon File has the following to say about the
9531 prefix "YA" in the name of a software product.
9535 Yet Another. adj. 1. Of your own work: A
9536 humorous allusion often used in titles to acknowledge that the
9537 topic is not original, though the content is. As in "Yet Another
9538 AI Group" or "Yet Another Simulated Annealing Algorithm".
9540 others' work: Describes something of which there are already far
9545 <appendix id="credits">
9546 <title>Credits</title>
9548 This appendix lists individuals that have contributed in the development
9549 of &yaz;. Some have contributed with code, while others have provided bug
9550 fixes or suggestions. If we're missing somebody, of if you, for
9551 whatever reason, don't like to be listed here, let us know.
9561 Morten Bøgeskov
9582 Mads Bondo Dydensborg
9591 Morten Garkier Hendriksen
9648 Tom André Øverland
9654 <!-- Keep this comment at the end of the file
9657 nxml-child-indent: 1