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14 <title>YAZ User's Guide and Reference</title>
16 <author><firstname>Sebastian</firstname><surname>Hammer</surname></author>
17 <author><firstname>Adam</firstname><surname>Dickmeiss</surname></author>
18 <author><firstname>Mike</firstname><surname>Taylor</surname></author>
19 <author><firstname>Heikki</firstname><surname>Levanto</surname></author>
20 <author><firstname>Dennis</firstname><surname>Schafroth</surname></author>
22 <releaseinfo>&version;</releaseinfo>
24 <year>©right-year;</year>
25 <holder>Index Data</holder>
29 This document is the programmer's guide and reference to the &yaz;
30 package version &version;. &yaz; is a compact toolkit that provides
31 access to the Z39.50 and SRU/Solr protocols, as well as a set of
32 higher-level tools for implementing the server and client
34 The documentation can be used on its own, or as a reference when
35 looking at the example applications provided with the package.
40 <imagedata fileref="common/id.png" format="PNG"/>
43 <imagedata fileref="common/id.eps" format="EPS"/>
48 <chapter id="introduction">
49 <title>Introduction</title>
51 &yaz; is a C/C++ library for information retrieval applications
52 using the Z39.50/SRU/Solr protocols for information retrieval.
60 <ulink url="&url.z39.50;">Z39.50</ulink> version 3 support.
61 Amendments and Z39.50-2002 revision is supported.
67 <ulink url="&url.sru;">SRU GET/POST/SOAP</ulink>
68 version 1.1, 1.2 and 2.0 (over HTTP and HTTPS).
73 Includes BER encoders/decoders for the
74 <ulink url="&url.ill;">ISO ILL</ulink>
81 <ulink url="&url.solr;">Solr</ulink> Web Service version 1.4.x
87 Supports the following transports: BER over TCP/IP
88 (<ulink url="&url.ber.over.tcpip;">RFC1729</ulink>),
89 BER over unix local socket, and
90 <ulink url="&url.http.1.1;">HTTP 1.1</ulink>.
95 Secure Socket Layer support using
96 <ulink url="&url.gnutls;">GnuTLS</ulink>.
97 If enabled, &yaz; uses HTTPS transport (for SOAP) or
98 "Secure BER" (for Z39.50).
104 <ulink url="&url.zoom;">ZOOM</ulink> C API implementing
105 Z39.50, SRU and Solr Web Service.
110 The &yaz; library offers a set of useful utilities
111 related to the protocols, such as MARC (ISO2709) parser,
112 CCL (ISO8777) parser,
113 <ulink url="&url.cql;">CQL</ulink>
114 parser, memory management routines, character set conversion.
119 Portable code. &yaz; compiles out-of-the box on most Unixes and
120 on Windows using Microsoft Visual C++.
125 Fast operation. The C based BER encoders/decoders as well
126 as the server component of &yaz; is very fast.
131 Liberal license that allows for commercial use of &yaz;.
137 <sect1 id="introduction.reading">
138 <title>Reading this Manual</title>
140 Most implementors only need to read a fraction of the
141 material in thie manual, so a quick walkthrough of the chapters
147 <xref linkend="installation"/> contains installation
148 instructions for &yaz;. You don't need reading this
149 if you expect to download &yaz; binaries.
150 However, the chapter contains information about how
151 to make <emphasis>your</emphasis> application link
157 <xref linkend="zoom"/> describes the ZOOM API of &yaz;.
158 This is definitely worth a read if you wish to develop a Z39.50/SRU
164 <xref linkend="server"/> describes the generic frontend server
165 and explains how to develop server Z39.50/SRU applications for &yaz;.
166 Obviously worth reading if you're to develop a server.
171 <xref linkend="yaz-client"/> describes how to use the &yaz; Z39.50
172 client. If you're developer and wish to test your server
173 or a server from another party, you might find this chapter
179 <xref linkend="asn"/> documents the most commonly used Z39.50
180 C data structures offered by the &yaz; API. Client
181 developers using ZOOM and non-Z39.50 implementors may skip this.
186 <xref linkend="soap"/> describes how SRU and SOAP is used
187 in &yaz;. Only if you're developing SRU applications
188 this section is a must.
193 <xref linkend="tools"/> contains sections for the various
194 tools offered by &yaz;. Scan through the material quickly
195 and see what's relevant to you! SRU implementors
196 might find the <link linkend="cql">CQL</link> section
202 <xref linkend="odr"/> goes through the details of the
203 ODR module which is the work horse that encodes and decodes
204 BER packages. Implementors using ZOOM only, do <emphasis>not</emphasis>
206 Most other Z39.50 implementors only need to read the first two
207 sections (<xref linkend="odr.introduction"/> and
208 <xref linkend="odr.use"/>).
213 <xref linkend="comstack"/> describes the network layer module
214 COMSTACK. Implementors using ZOOM or the generic frontend server
215 may skip this. Others, presumably, handling client/server
216 communication on their own should read this.
221 <sect1 id="introduction.api">
222 <title>The API</title>
224 The <ulink url="&url.yaz;">&yaz;</ulink>
225 toolkit offers several different levels of access to the
226 <ulink url="&url.z39.50;">ISO23950/Z39.50</ulink>,
227 <ulink url="&url.ill;">ILL</ulink> and
228 <ulink url="&url.sru;">SRU</ulink>
230 The level that you need to use depends on your requirements, and
231 the role (server or client) that you want to implement.
232 If you're developing a client application you should consider the
233 <link linkend="zoom">ZOOM</link> API.
234 It is, by far, the easiest way to develop clients in C.
235 Server implementers should consider the
236 <link linkend="server">generic frontend server</link>.
237 None of those high-level APIs support the whole protocol, but
238 they do include most facilities used in existing Z39.50 applications.
241 If you're using 'exotic' functionality (meaning anything not included in
242 the high-level APIs), developing non-standard extensions to Z39.50 or
243 you're going to develop an ILL application you'll have to learn the lower
247 The YAZ toolkit modules is shown in figure <xref linkend="yaz.layer"/>.
249 <figure id="yaz.layer">
250 <title>YAZ layers</title>
253 <imagedata fileref="apilayer.png" format="PNG"/>
256 <imagedata fileref="apilayer.eps" format="EPS"/>
261 There are four layers.
264 <para>A client or server application (or both).
265 This layer includes ZOOM and the generic frontend server.
270 The second layer provides a C represenation of the
271 protocol units (packages) for Z39.50 ASN.1, ILL ASN.1,
277 The third layer encodes and decodes protocol data units to
278 simple packages (buffer with certain length). The &odr; module
279 encodes and decodes BER whereas the HTTP modules encodes and
280 decodes HTTP ruquests/responses.
285 The lowest layer is &comstack; which exchanges the encoded packages
286 with a peer process over a network.
292 The &asn; module represents the ASN.1 definition of
293 the Z39.50 protocol. It establishes a set of type and
294 structure definitions, with one structure for each of the top-level
295 PDUs, and one structure or type for each of the contained ASN.1 types.
296 For primitive types, or other types that are defined by the ASN.1
297 standard itself (such as the EXTERNAL type), the C representation is
298 provided by the &odr; (Open Data Representation) subsystem.
301 &odr; is a basic mechanism for representing an
302 ASN.1 type in the C programming language, and for implementing BER
303 encoders and decoders for values of that type. The types defined in
304 the &asn; module generally have the prefix <literal>Z_</literal>, and
305 a suffix corresponding to the name of the type in the ASN.1
306 specification of the protocol (generally Z39.50-1995). In the case of
307 base types (those originating in the ASN.1 standard itself), the prefix
308 <literal>Odr_</literal> is sometimes seen. Either way, look for
309 the actual definition in either <filename>z-core.h</filename> (for the types
310 from the protocol), <filename>odr.h</filename> (for the primitive ASN.1
312 The &asn; library also provides functions (which are, in turn,
313 defined using &odr; primitives) for encoding and decoding data values.
314 Their general form is
316 <funcprototype><funcdef>int <function>z_<replaceable>xxx</replaceable></function></funcdef>
317 <paramdef>ODR <parameter>o</parameter></paramdef>
318 <paramdef>Z_<replaceable>xxx</replaceable> **<parameter>p</parameter></paramdef>
319 <paramdef>int <parameter>optional</parameter></paramdef>
320 <paramdef>const char *<parameter>name</parameter></paramdef>
323 (note the lower-case "z" in the function name)
327 If you are using the premade definitions of the &asn; module, and you
328 are not adding new protocol of your own, the only parts of &odr; that you
329 need to worry about are documented in
330 <xref linkend="odr.use"/>.
334 When you have created a BER-encoded buffer, you can use the &comstack;
335 subsystem to transmit (or receive) data over the network. The &comstack;
336 module provides simple functions for establishing a connection
337 (passively or actively, depending on the role of your application),
338 and for exchanging BER-encoded PDUs over that connection. When you
339 create a connection endpoint, you need to specify what transport to
340 use (TCP/IP, SSL or UNIX sockets).
341 For the remainder of the connection's lifetime, you don't have
342 to worry about the underlying transport protocol at all - the &comstack;
343 will ensure that the correct mechanism is used.
346 We call the combined interfaces to &odr;, &asn;, and &comstack; the service
347 level API. It's the API that most closely models the Z39.50
348 service/protocol definition, and it provides unlimited access to all
349 fields and facilities of the protocol definitions.
352 The reason that the &yaz; service-level API is a conglomerate of the
353 APIs from three different submodules is twofold. First, we wanted to allow
354 the user a choice of different options for each major task. For instance,
355 if you don't like the protocol API provided by &odr;/&asn;, you
356 can use SNACC or BERUtils instead, and still have the benefits of the
357 transparent transport approach of the &comstack; module. Secondly,
358 we realize that you may have to fit the toolkit into an existing
359 event-processing structure, in a way that is incompatible with
360 the &comstack; interface or some other part of &yaz;.
364 <chapter id="installation">
365 <title>Compilation and Installation</title>
366 <sect1 id="installation-introduction">
367 <title>Introduction</title>
369 The latest version of the software will generally be found at:
372 <ulink url="&url.yaz.download;"/>
375 We have tried our best to keep the software portable, and on many
376 platforms, you should be able to compile everything with little or
380 The software is regularly tested on
381 <ulink url="&url.debian;">Debian GNU/Linux</ulink>,
382 <ulink url="&url.centos;">CentOS</ulink>,
383 <ulink url="&url.ubuntu;">Ubuntu Linux</ulink>,
384 <ulink url="&url.freebsd;">FreeBSD (i386)</ulink>,
385 <ulink url="&url.macosx;">MAC OSX</ulink>,
386 <ulink url="&url.solaris;">Solaris</ulink>,
387 Windows 7, Windows XP.
390 Some versions have be known to work on HP/UX,
391 DEC Unix, <ulink url="&url.netbsd;">NetBSD</ulink>,
392 <ulink url="&url.openbsd;">OpenBSD</ulink>,
394 Data General DG/UX (with some CFLAGS tinkering),
395 SGI/IRIX, DDE Supermax, Apple Macintosh (using the Codewarrior programming
396 environment and the GUSI socket libraries),
400 If you move the software to other platforms, we'd be grateful if you'd
401 let us know about it. If you run into difficulties, we will try to help
402 if we can, and if you solve the problems, we would be happy to include
403 your fixes in the next release. So far, we have mostly avoided
404 <literal>#ifdefs</literal> for individual platforms, and we'd
405 like to keep it that way as far as it makes sense.
408 We maintain a mailing-list for the purpose of announcing new releases and
409 bug-fixes, as well as general discussion. Subscribe by
411 <ulink url="&url.yaz.mailinglist;">here</ulink>.
412 General questions and problems can be directed at
413 <ulink url="&url.yaz.mail;"/>, or the address given at the top of
417 <sect1 id="installation.unix"><title>UNIX</title>
420 <ulink url="&url.debian;">Debian GNU/Linux</ulink> (i386 and amd64),
421 <ulink url="&url.ubuntu;">Ubuntu</ulink> (i386 and amd64)
423 <ulink url="&url.centos;">CentOS</ulink> (amd64 only) packages for &yaz;.
424 You should be able to create packages for other CPUs by building
425 them from the source package.
428 YAZ is also part of several packages repositories. Some of them are
433 Solaris CSW: <ulink url="http://www.opencsw.org/packages/yaz/"/>
438 Solaris: <ulink url="http://unixpackages.com"/>
443 FreeBSD: <ulink url="http://www.freshports.org/net/yaz"/>
448 Debian: <ulink url="http://packages.debian.org/search?keywords=yaz"/>
453 Ubuntu: <ulink url="https://launchpad.net/ubuntu/+source/yaz"/>
459 <ulink url="http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/net/yaz/README.html"/>
463 <sect2 id="installation.source.unix">
464 <title>Compiling from source on Unix</title>
466 Note that if your system doesn't have a native ANSI C compiler, you may
467 have to acquire one separately. We recommend
468 <ulink url="&url.gcc;">GCC</ulink>.
471 If you wish to use character set conversion facilities in &yaz; or if you
472 are compiling &yaz; for use with Zebra it is a good idea to ensure that
473 the iconv library is installed. Some Unixes today already have it
475 <ulink url="&url.libiconv;">GNU libiconv</ulink>.
478 YAZ 3.0.16 and later includes a wrapper for the
479 <ulink url="&url.icu;">ICU</ulink>
480 (International Components for Unicode).
481 In order to use this, the developer version of the ICU library
482 must be available. ICU support is recommended for applications
483 such as Pazpar2 and Zebra.
486 The <ulink url="&url.libxslt;">libxslt</ulink>,
487 <ulink url="&url.libxml2;">libxml2</ulink> librararies are required
488 if &yaz; is to support SRU/Solr.
489 These libraries are very portable and should compile out-of-the
490 box on virtually all Unix platforms. It is available in binary
491 forms for Linux and others.
495 <ulink url="&url.autoconf;">Autoconf</ulink>,
496 <ulink url="&url.automake;">Automake</ulink> and
497 <ulink url="&url.libtool;">Libtool</ulink>
498 are used to generate Makefiles and configure &yaz; for the system.
499 You do <emphasis>not</emphasis> these tools unless you're using the
500 Git version of &yaz;.
503 The CQL parser for &yaz; is built using
504 GNU <ulink url="&url.bison;">Bison</ulink>.
505 This tool is only needed if you're using the Git version of &yaz;.
508 &yaz; includes a tiny ASN.1 compiler. This compiler is
509 written in <ulink url="&url.tcl;">Tcl</ulink>.
510 But as for Bison you do not need it unless you're using Git
511 version of &yaz; or you're using the compiler to built own codecs
515 Generally it should be sufficient to run configure without options,
522 The configure script attempts to use use the C compiler specified by
523 the <literal>CC</literal> environment variable. If not set, GNU C will be
524 used if it is available. The <literal>CFLAGS</literal> environment
525 variable holds options to be passed to the C compiler. If you're using
526 Bourne-compatible shell you may pass something like this to use a
527 particular C compiler with optimization enabled:
530 CC=/opt/ccs/bin/cc CFLAGS=-O ./configure
533 To customize &yaz;, the configure script also accepts a set of options.
534 The most important are:
538 <literal>--prefix</literal>=<replaceable>prefix</replaceable>
541 <para>Specifies installation prefix for &yaz;. This is
542 only needed if you run <literal>make install</literal> later to
543 perform a "system" installation. The prefix is
544 <literal>/usr/local</literal> if not specified.
550 <literal>--enable-tcpd</literal>
553 <para>The front end server will be built using Wietse's
554 <ulink url="&url.tcpwrapper;">TCP wrapper library</ulink>.
555 It allows you to allow/deny clients depending on IP number.
556 The TCP wrapper library is often used in GNU/Linux and
560 <refentrytitle>hosts_access</refentrytitle>
561 <manvolnum>5</manvolnum>
565 <refentrytitle>tcpd</refentrytitle>
566 <manvolnum>8</manvolnum>
573 <literal>--enable-threads</literal>
576 <para>&yaz; will be built using POSIX threads.
577 Specifically, <constant>_REENTRANT</constant> will be defined during
584 <literal>--disable-shared</literal>
587 <para>The make process will not create shared
588 libraries (also known as shared objects <filename>.so</filename>).
589 By default, shared libraries are created -
590 equivalent to <literal>--enable-shared</literal>.
596 <literal>--disable-shared</literal>
599 <para>The make process will not create
600 static libraries (<filename>.a</filename>).
601 By default, static libraries are created -
602 equivalent to <literal>--enable-static</literal>.
608 <literal>--with-iconv</literal>[=<replaceable>prefix</replaceable>]
611 <para>Compile &yaz; with iconv library in directory
612 <replaceable>prefix</replaceable>. By default configure will
613 search for iconv on the system. Use this option if it
614 doesn't find iconv. Alternatively,
615 <literal>--without-iconv</literal>, can be uset to force &yaz;
622 <literal>--with-xslt</literal>[=<replaceable>prefix</replaceable>]
625 <para>Compile &yaz; with
626 <ulink url="&url.libxslt;">libxslt</ulink> in directory
627 <replaceable>prefix</replaceable>.
628 Use this option if you want XSLT and XML support.
629 By default, configure will
630 search for libxslt on the system. Use this option if it
631 libxslt is not found automatically. Alternatively,
632 <literal>--without-xslt</literal>, can be used to force &yaz;
639 <literal>--with-xml2</literal>[=<replaceable>prefix</replaceable>]
642 <para>Compile &yaz; with
643 <ulink url="&url.libxml2;">libxml2</ulink> in directory
644 <replaceable>prefix</replaceable>.
645 Use this option if you want &yaz; to use XML and support SRU/Solr.
646 By default, configure will
647 search for libxml2 on the system. Use this option if it
648 libxml2 is not found automatically. Alternatively,
649 <literal>--without-xml2</literal>, can be used to force &yaz;
653 Note that option <literal>--with-xslt</literal>
654 also enables libxml2.
660 <literal>--with-gnutls</literal>[=<replaceable>prefix</replaceable>]
663 <para>&yaz; will be linked with the GNU TLS libraries and
664 an SSL COMSTACK will be provided. By default configure enables
665 SSL support for YAZ if the GNU TLS development libraries are found
672 <literal>--with-icu</literal>[=<replaceable>prefix</replaceable>]
675 <para>&yaz; will be linked the
676 <ulink url="&url.icu;">ICU</ulink> library in the prefix if given.
677 If prefix is not given, the libraries exposed by the script
678 <application>icu-config</application> will be used if found.
685 <literal>--with-libgcrypt</literal>[=<replaceable>prefix</replaceable>]
688 <para>&yaz; will be linked with
689 <ulink url="&url.libgcrypt;">Libgcrypt</ulink> in the prefix if given.
690 If prefix is not given, the libraries exposed by the script
691 <application>libgcrypt-config</application> will be used if found.
697 <literal>--with-memcached</literal>
700 <para>&yaz; will be linked with
701 <ulink url="&url.libmemcached;">libMemcached</ulink> to allow
702 for result-set caching for ZOOM.
703 The prefix can not be given. Note that YAZ will only search
704 for libMemcached if Libgcrypt is also enabled.
705 Note that 0.40 of libmemcached is required.
711 <literal>--with-redis</literal>
714 <para>&yaz; will be linked with the hiredis C library
715 to allow for result-set caching for ZOOM on a
716 <ulink url="&url.redis;">redis</ulink> server.
717 The prefix can not be given. Note that YAZ will only search
718 for hiredis if Libgcrypt is also enabled.
726 When configured, build the software by typing:
732 The following files are generated by the make process:
735 <term><filename>src/libyaz.la</filename></term>
737 Main &yaz; library. This is no ordinary library. It's
739 By default, &yaz; creates a static library in
740 <filename>lib/.libs/libyaz.a</filename>.
744 <term><filename>src/libyaz_server.la</filename></term>
746 Generic Frontend server. This is an add-on for libyaz.la.
747 Code in this library uses POSIX threads functions - if POSIX
748 threads are available on the platform.
752 <term><filename>src/libyaz_icu.la</filename></term>
754 Functions that wrap the ICU library.
758 <term><filename>ztest/yaz-ztest</filename></term>
759 <listitem><para>Test Z39.50 server.
763 <term><filename>client/yaz-client</filename></term>
764 <listitem><para>Z39.50 client for testing the protocol.
765 See chapter <link linkend="yaz-client">
766 YAZ client</link> for more information.
770 <term><filename>util/yaz-config</filename></term>
771 <listitem><para>A Bourne-shell script, generated by configure, that
772 specifies how external applications should compile - and link with
777 <term><filename>util/yaz-asncomp</filename></term>
778 <listitem><para>The ASN.1 compiler for &yaz;. Requires the
779 Tcl Shell, <application>tclsh</application>, in
780 <literal>PATH</literal> to operate.
784 <term><filename>util/yaz-iconv</filename></term>
785 <listitem><para>This program converts data in one character set to
786 another. This command exercises the YAZ character set
791 <term><filename>util/yaz-marcdump</filename></term>
792 <listitem><para>This program parses ISO2709 encoded MARC records
793 and prints them in line-format or XML.
797 <term><filename>util/yaz-icu</filename></term>
798 <listitem><para>This program exposes the ICU wrapper library if that
799 is enabled for YAZ. Only if ICU is available this program is
804 <term><filename>util/yaz-url</filename></term>
805 <listitem><para>This program is a simple HTTP page fetcher ala
810 <term><filename>zoom/zoomsh</filename></term>
812 A simple shell implemented on top of the
813 <link linkend="zoom">ZOOM</link> functions.
814 The shell is a command line application that allows you to enter
815 simple commands to perform ZOOM operations.
819 <term><filename>zoom/zoomtst1</filename>,
820 <filename>zoom/zoomtst2</filename>, ..</term>
822 Several small applications that demonstrates the ZOOM API.
828 If you wish to install &yaz; in system directories
829 <filename>/usr/local/bin</filename>,
830 <filename>/usr/local/lib</filename> .. etc, you can type:
836 You probably need to have root access in order to perform this.
837 You must specify the <literal>--prefix</literal> option for configure if
838 you wish to install &yaz; in other directories than the default
839 <filename>/usr/local/</filename>.
842 If you wish to perform an un-installation of &yaz;, use:
848 This will only work if you haven't reconfigured &yaz; (and therefore
849 changed installation prefix). Note that uninstall will not
850 remove directories created by make install, e.g.
851 <filename>/usr/local/include/yaz</filename>.
854 <sect2 id="installation-linking-yaz-unix">
855 <title>How to make apps using YAZ on UNIX</title>
857 This section describes how to compile - and link your own
858 applications using the &yaz; toolkit.
859 If you're used to Makefiles this shouldn't be hard. As for
860 other libraries you have used before, you have to set a proper include
861 path for your C/C++ compiler and specify the location of
862 &yaz; libraries. You can do it by hand, but generally we suggest
863 you use the <filename>yaz-config</filename> that is generated
864 by <filename>configure</filename>. This is especially
865 important if you're using the threaded version of &yaz; which
866 require you to pass more options to your linker/compiler.
869 The <filename>yaz-config</filename> script accepts command line
870 options that makes the <filename>yaz-config</filename> script print
871 options that you should use in your make process.
872 The most important ones are:
873 <literal>--cflags</literal>, <literal>--libs</literal>
874 which prints C compiler flags, and linker flags respectively.
877 A small and complete <literal>Makefile</literal> for a C
878 application consisting of one source file,
879 <filename>myprog.c</filename>, may look like this:
881 YAZCONFIG=/usr/local/bin/yaz-config
882 CFLAGS=`$(YAZCONFIG) --cflags`
883 LIBS=`$(YAZCONFIG) --libs`
885 $(CC) $(CFLAGS) -o myprog myprog.o $(LIBS)
889 The CFLAGS variable consists of a C compiler directive that will set
890 the include path to the <emphasis>parent</emphasis> directory
891 of <filename>yaz</filename>. That is, if &yaz; header files were
892 installed in <filename>/usr/local/include/yaz</filename>,
893 then include path is set to <filename>/usr/local/include</filename>.
894 Therefore, in your applications you should use
896 #include <yaz/proto.h>
898 and <emphasis>not</emphasis>
900 #include <proto.h>
904 For Libtool users, the <filename>yaz-config</filename> script provides
905 a different variant of option <literal>--libs</literal>, called
906 <literal>--lalibs</literal> that returns the name of the
907 Libtool archive(s) for &yaz; rather than the ordinary ones.
910 For applications using the threaded version of &yaz;,
911 specify <literal>threads</literal> after the
912 other options. When <literal>threads</literal> is given,
913 more flags and linker flags will be printed by
914 <filename>yaz-config</filename>. If our previous example was
915 using threads, you'd have to modify the lines that set
916 <literal>CFLAGS</literal> and <literal>LIBS</literal> as
919 CFLAGS=`$(YAZCONFIG) --cflags threads`
920 LIBS=`$(YAZCONFIG) --libs threads`
922 There is no need specify POSIX thread libraries in your Makefile.
923 The <literal>LIBS</literal> variable includes that as well.
927 <sect1 id="installation.win32">
928 <title>Windows</title>
929 <para>The easiest way to install YAZ on Windows is by downloading
931 <ulink url="&url.yaz.download.win32;">here</ulink>.
932 The installer comes with source too - in case you wish to
933 compile YAZ with different compiler options, etc.
936 <sect2 id="installation.win32.source">
937 <title>Compiling from Source on Windows</title>
939 &yaz; is shipped with "makefiles" for the NMAKE tool that comes
940 with <ulink url="&url.vstudio;">
941 Microsoft Visual Studio</ulink>. It has been tested with
942 Microsoft Visual Studio 2013.
945 Start a command prompt and switch the sub directory
946 <filename>WIN</filename> where the file <filename>makefile</filename>
947 is located. Customize the installation by editing the
948 <filename>makefile</filename> file (for example by using notepad).
949 The following summarizes the most important settings in that file:
952 <term><literal>DEBUG</literal></term>
954 If set to 1, the software is
955 compiled with debugging libraries (code generation is
956 multi-threaded debug DLL).
957 If set to 0, the software is compiled with release libraries
958 (code generation is multi-threaded DLL).
962 <term><literal>HAVE_TCL</literal>, <literal>TCL</literal></term>
964 If <literal>HAVE_TCL</literal> is set to 1, nmake will
965 use the ASN.1 compiler (<ulink url="&url.tcl;">Tcl</ulink> based).
966 You must set <literal>TCL</literal> to the full path of the Tcl
967 interpreter. A Windows version of Tcl is part of
968 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
971 If you do not have Tcl installed, set
972 <literal>HAVE_TCL</literal> to 0.
976 <term><literal>HAVE_BISON</literal>,
977 <literal>BISON</literal></term>
979 If GNU Bison is present, you might set <literal>HAVE_BISON</literal>
980 to 1 and specify the Bison executable in <literal>BISON</literal>.
981 Bison is only required if you use the Git version of
982 YAZ or if you modify the grammar for CQL
983 (<filename>cql.y</filename>).
986 A Windows version of GNU Bison is part of
987 <ulink url="&url.gitwindows;">Git for Windows</ulink>.
991 <term><literal>HAVE_ICONV</literal>,
992 <literal>ICONV_DIR</literal></term>
994 If <literal>HAVE_ICONV</literal> is set to 1, YAZ is compiled
995 with iconv support. In this configuration, set
996 <literal>ICONV_DIR</literal> to the iconv source directory.
1000 <term><literal>HAVE_LIBXML2</literal>,
1001 <literal>LIBXML2_DIR</literal></term>
1004 If <literal>HAVE_LIBXML2</literal> is set to 1, YAZ is compiled
1005 with SRU support. In this configuration, set
1006 <literal>LIBXML2_DIR</literal> to the
1007 <ulink url="&url.libxml2;">libxml2</ulink> source directory.
1010 You can get pre-compiled Libxml2+Libxslt DLLs and headers from
1011 <ulink url="&url.libxml2.download.windows;">here</ulink>.
1012 Should you with to compile those libraries yourself, refer to
1013 to <xref linkend="installation.windows.libxml2"/>
1018 <term><literal>HAVE_LIBXSLT</literal>,
1019 <literal>LIBXSLT_DIR</literal></term>
1022 If <literal>HAVE_LIBXSLT</literal> is set to 1, YAZ is compiled
1023 with XSLT support. In this configuration, set
1024 <literal>LIBXSLT_DIR</literal> to the
1025 <ulink url="&url.libxslt;">libxslt</ulink> source directory.
1029 libxslt depends libxml2.
1035 <term><literal>HAVE_ICU</literal>,
1036 <literal>ICU_DIR</literal></term>
1039 If <literal>HAVE_ICU</literal> is set to 1, YAZ is compiled
1040 with <ulink url="&url.icu;">ICU</ulink> support.
1041 In this configuration, set
1042 <literal>ICU_DIR</literal> to the
1043 <ulink url="&url.icu;">ICU</ulink> source directory.
1050 When satisfied with the settings in the makefile, type
1057 If the <filename>nmake</filename> command is not found on your system
1058 you probably haven't defined the environment variables required to
1059 use that tool. To fix that, find and run the batch file
1060 <filename>vcvars32.bat</filename>. You need to run it from within
1061 the command prompt or set the environment variables "globally";
1062 otherwise it doesn't work.
1066 If you wish to recompile &yaz; - for example if you modify
1067 settings in the <filename>makefile</filename> you can delete
1068 object files, etc by running.
1074 The following files are generated upon successful compilation:
1077 <term><filename>bin/yaz&soversion;.dll</filename> /
1078 <filename>bin/yaz&soversion;d.dll</filename></term>
1080 &yaz; Release/Debug DLL.
1084 <term><filename>lib/yaz&soversion;.lib</filename> /
1085 <filename>lib/yaz&soversion;d.lib</filename></term>
1087 Import library for <filename>yaz&soversion;.dll</filename> /
1088 <filename>yaz&soversion;d.dll</filename>.
1092 <term><filename>bin/yaz_cond&soversion;.dll</filename> /
1093 <filename>bin/yaz_cond&soversion;d.dll</filename></term>
1095 Release/Debug DLL for condition variable utilities (condvar.c).
1099 <term><filename>lib/yaz_cond&soversion;.lib</filename> /
1100 <filename>lib/yaz_cond&soversion;d.lib</filename></term>
1102 Import library for <filename>yaz_cond&soversion;.dll</filename> /
1103 <filename>yaz_cond&soversion;d.dll</filename>.
1107 <term><filename>bin/yaz_icu&soversion;.dll</filename> /
1108 <filename>bin/yaz_icu&soversion;d.dll</filename></term>
1110 Release/Debug DLL for the ICU wrapper utility.
1111 Only build if HAVE_ICU is 1.
1115 <term><filename>lib/yaz_icu&soversion;.lib</filename> /
1116 <filename>lib/yaz_icu&soversion;d.lib</filename></term>
1118 Import library for <filename>yaz_icu&soversion;.dll</filename> /
1119 <filename>yaz_icu&soversion;d.dll</filename>.
1123 <term><filename>bin/yaz-ztest.exe</filename></term>
1125 Z39.50 multi-threaded test/example server. It's a WIN32
1126 console application.
1130 <term><filename>bin/yaz-client.exe</filename></term>
1132 &yaz; Z39.50 client application. It's a WIN32 console application.
1133 See chapter <link linkend="yaz-client">YAZ client</link> for more
1138 <term><filename>bin/yaz-icu.exe</filename></term>
1139 <listitem><para>This program exposes the ICU wrapper library if that
1140 is enabled for YAZ. Only if ICU is available this program is
1145 <term><filename>bin/zoomsh.exe</filename></term>
1147 Simple console application implemented on top of the
1148 <link linkend="zoom">ZOOM</link> functions.
1149 The application is a command line shell that allows you to enter
1150 simple commands to perform ZOOM operations.
1154 <term><filename>bin/zoomtst1.exe</filename>,
1155 <filename>bin/zoomtst2.exe</filename>, ..</term>
1157 Several small applications that demonstrates the ZOOM API.
1164 <sect2 id="installation-linking-yaz-win32">
1165 <title>How to make apps using YAZ on Windows</title>
1167 This section will go though the process of linking your Windows
1168 applications with &yaz;.
1171 Some people are confused by the fact that we use the nmake
1172 tool to build &yaz;. They think they have to do that too - in order
1173 to make their Windows applications work with &yaz;. The good news is that
1174 you don't have to. You can use the integrated environment of
1175 Visual Studio if desired for your own application.
1178 When setting up a project or Makefile you have to set the following:
1181 <term>include path</term>
1183 Set it to the <filename>include</filename> directory of &yaz;.
1187 <term>import library <filename>yaz&soversion;.lib</filename></term>
1189 You must link with this library. It's located in the
1190 sub directory <filename>lib</filename> of &yaz;.
1191 If you want to link with the debug version of &yaz;, you must
1192 link against <filename>yaz&soversion;d.lib</filename> instead.
1196 <term>dynamic link library
1197 <filename>yaz&soversion;.dll</filename>
1200 This DLL must be in your execution path when you invoke
1201 your application. Specifically, you should distribute this
1202 DLL with your application.
1209 <sect2 id="installation.windows.libxml2">
1210 <title>Compiling Libxml2 and Libxslt on windows</title>
1212 Download libxml2 and Libxslt source and unpack it.
1213 In the example below we install Libxml2 2.9.2 and Libxslt 1.1.28
1214 for 32-bit, so we use the destination directories
1215 libxml2.2.9.2.win32 and libxslt-1.1.28.win32 to reflect both
1216 version and architecture.
1219 cscript configure.js prefix=c:\libxml2-2.9.2.win32 iconv=no
1225 For Libxslt it is similar. We must ensure that compilation of
1226 Libxslt links against the already installed libxml2.
1229 cscript configure.js prefix=c:\libxslt-1.1.28.win32 iconv=no \
1230 lib=c:\libxmlt-2.9.2.win32\lib \
1231 include=c:\libxmlt-2.9.2.win32\include\libxml2
1241 ### Still to document:
1242 ZOOM_connection_errcode(c)
1243 ZOOM_connection_errmsg(c)
1244 ZOOM_connection_addinfo(c)
1245 ZOOM_connection_addinfo(c)
1246 ZOOM_connection_diagset(c);
1247 ZOOM_connection_save_apdu_wrbuf
1248 ZOOM_diag_str(error)
1249 ZOOM_resultset_record_immediate(s, pos)
1250 ZOOM_resultset_cache_reset(r)
1251 ZOOM_options_set_callback(opt, function, handle)
1252 ZOOM_options_create_with_parent2(parent1, parent2)
1253 ZOOM_options_getl(opt, name, len)
1254 ZOOM_options_setl(opt, name, value, len)
1255 ZOOM_options_get_bool(opt, name, defa)
1256 ZOOM_options_get_int(opt, name, defa)
1257 ZOOM_options_set_int(opt, name, value)
1262 &zoom; is an acronym for 'Z39.50 Object-Orientation Model' and is
1263 an initiative started by Mike Taylor (Mike is from the UK, which
1264 explains the peculiar name of the model). The goal of &zoom; is to
1265 provide a common Z39.50 client API not bound to a particular
1266 programming language or toolkit.
1269 From YAZ version 2.1.12, <ulink url="&url.sru;">SRU</ulink> is supported.
1270 You can make SRU ZOOM connections by specifying scheme
1271 <literal>http://</literal> for the hostname for a connection.
1272 The dialect of SRU used is specified by the value of the
1273 connection's <literal>sru</literal> option, which may be SRU over
1274 HTTP GET (<literal>get</literal>),
1275 SRU over HTTP POST (<literal>post</literal>), (SRU over
1276 SOAP) (<literal>soap</literal>) or <literal>solr</literal>
1277 (<ulink url="&url.solr;">Solr</ulink> Web Service).
1278 Using the facility for embedding options in target strings, a
1279 connection can be forced to use SRU rather the SRW (the default) by
1280 prefixing the target string with <literal>sru=get,</literal>, like this:
1281 <literal>sru=get,http://sru.miketaylor.org.uk:80/sru.pl</literal>
1284 <ulink url="&url.solr;">Solr</ulink> protocol support was added to
1285 YAZ in version 4.1.0, as a dialect of a SRU protocol, since both are
1286 HTTP based protocols.
1289 The lack of a simple Z39.50 client API for &yaz; has become more
1290 and more apparent over time. So when the first &zoom; specification
1292 an implementation for &yaz; was quickly developed. For the first time, it is
1293 now as easy (or easier!) to develop clients than servers with &yaz;. This
1294 chapter describes the &zoom; C binding. Before going further, please
1295 reconsider whether C is the right programming language for the job.
1296 There are other language bindings available for &yaz;, and still
1298 are in active development. See the
1299 <ulink url="&url.zoom;">ZOOM web-site</ulink> for
1303 In order to fully understand this chapter you should read and
1304 try the example programs <literal>zoomtst1.c</literal>,
1305 <literal>zoomtst2.c</literal>, .. in the <literal>zoom</literal>
1309 The C language misses features found in object oriented languages
1310 such as C++, Java, etc. For example, you'll have to manually,
1311 destroy all objects you create, even though you may think of them as
1312 temporary. Most objects has a <literal>_create</literal> - and a
1313 <literal>_destroy</literal> variant.
1314 All objects are in fact pointers to internal stuff, but you don't see
1315 that because of typedefs. All destroy methods should gracefully ignore a
1316 <literal>NULL</literal> pointer.
1319 In each of the sections below you'll find a sub section called
1320 protocol behavior, that describes how the API maps to the Z39.50
1323 <sect1 id="zoom-connections">
1324 <title>Connections</title>
1325 <para>The Connection object is a session with a target.
1328 #include <yaz/zoom.h>
1330 ZOOM_connection ZOOM_connection_new(const char *host, int portnum);
1332 ZOOM_connection ZOOM_connection_create(ZOOM_options options);
1334 void ZOOM_connection_connect(ZOOM_connection c, const char *host,
1336 void ZOOM_connection_destroy(ZOOM_connection c);
1339 Connection objects are created with either function
1340 <function>ZOOM_connection_new</function> or
1341 <function>ZOOM_connection_create</function>.
1342 The former creates and automatically attempts to establish a network
1343 connection with the target. The latter doesn't establish
1344 a connection immediately, thus allowing you to specify options
1345 before establishing network connection using the function
1346 <function>ZOOM_connection_connect</function>.
1347 If the port number, <literal>portnum</literal>, is zero, the
1348 <literal>host</literal> is consulted for a port specification.
1349 If no port is given, 210 is used. A colon denotes the beginning of
1350 a port number in the host string. If the host string includes a
1351 slash, the following part specifies a database for the connection.
1354 You can prefix the host with a scheme followed by colon. The
1355 default scheme is <literal>tcp</literal> (Z39.50 protocol).
1356 The scheme <literal>http</literal> selects SRU/get over HTTP by default,
1357 but can overridded to use SRU/post, SRW and the Solr protocol.
1360 You can prefix the scheme-qualified host-string with one or more
1362 <literal><parameter>key</parameter>=<parameter>value</parameter></literal>
1363 sequences, each of which represents an option to be set into the
1364 connection structure <emphasis>before</emphasis> the
1365 protocol-level connection is forged and the initialization
1366 handshake takes place. This facility can be used to provide
1367 authentication credentials, as in host-strings such as:
1368 <literal>user=admin,password=halfAm4n,tcp:localhost:8017/db</literal>
1371 Connection objects should be destroyed using the function
1372 <function>ZOOM_connection_destroy</function>.
1375 void ZOOM_connection_option_set(ZOOM_connection c,
1376 const char *key, const char *val);
1378 void ZOOM_connection_option_setl(ZOOM_connection c,
1380 const char *val, int len);
1382 const char *ZOOM_connection_option_get(ZOOM_connection c,
1384 const char *ZOOM_connection_option_getl(ZOOM_connection c,
1389 The functions <function>ZOOM_connection_option_set</function> and
1390 <function>ZOOM_connection_option_setl</function> allows you to
1391 set an option given by <parameter>key</parameter> to the value
1392 <parameter>value</parameter> for the connection.
1393 For <function>ZOOM_connection_option_set</function>, the
1394 value is assumed to be a 0-terminated string. Function
1395 <function>ZOOM_connection_option_setl</function> specifies a
1396 value of a certain size (len).
1399 Functions <function>ZOOM_connection_option_get</function> and
1400 <function>ZOOM_connection_option_getl</function> returns
1401 the value for an option given by <parameter>key</parameter>.
1403 <table id="zoom-connection-options" frame="top">
1404 <title>ZOOM Connection Options</title>
1406 <colspec colwidth="4*" colname="name"></colspec>
1407 <colspec colwidth="7*" colname="description"></colspec>
1408 <colspec colwidth="3*" colname="default"></colspec>
1411 <entry>Option</entry>
1412 <entry>Description</entry>
1413 <entry>Default</entry>
1418 implementationName</entry><entry>Name of Your client
1419 </entry><entry>none</entry></row>
1421 user</entry><entry>Authentication user name
1422 </entry><entry>none</entry></row>
1424 group</entry><entry>Authentication group name
1425 </entry><entry>none</entry></row>
1427 password</entry><entry>Authentication password.
1428 </entry><entry>none</entry></row>
1430 authenticationMode</entry><entry>How authentication is encoded.
1431 </entry><entry>basic</entry></row>
1433 host</entry><entry>Target host. This setting is "read-only".
1434 It's automatically set internally when connecting to a target.
1435 </entry><entry>none</entry></row>
1437 proxy</entry><entry>Proxy host. If set, the logical host
1438 is encoded in the otherInfo area of the Z39.50 Init PDU
1439 with OID 1.2.840.10003.10.1000.81.1.
1440 </entry><entry>none</entry></row>
1442 clientIP</entry><entry>Client IP. If set, is
1443 encoded in the otherInfo area of a Z39.50 PDU with OID
1444 1.2.840.10003.10.1000.81.3. Holds the original IP addreses
1445 of a client. Is used of ZOOM is used in a gateway of some sort.
1446 </entry><entry>none</entry></row>
1448 async</entry><entry>If true (1) the connection operates in
1449 asynchronous operation which means that all calls are non-blocking
1451 <link linkend="zoom.events"><function>ZOOM_event</function></link>.
1452 </entry><entry>0</entry></row>
1454 maximumRecordSize</entry><entry> Maximum size of single record.
1455 </entry><entry>1 MB</entry></row>
1457 preferredMessageSize</entry><entry> Maximum size of multiple records.
1458 </entry><entry>1 MB</entry></row>
1460 lang</entry><entry> Language for negotiation.
1461 </entry><entry>none</entry></row>
1463 charset</entry><entry> Character set for negotiation.
1464 </entry><entry>none</entry></row>
1466 serverImplementationId</entry><entry>
1467 Implementation ID of server. (The old targetImplementationId
1468 option is also supported for the benefit of old applications.)
1469 </entry><entry>none</entry></row>
1471 targetImplementationName</entry><entry>
1472 Implementation Name of server. (The old
1473 targetImplementationName option is also supported for the
1474 benefit of old applications.)
1475 </entry><entry>none</entry></row>
1477 serverImplementationVersion</entry><entry>
1478 Implementation Version of server. (the old
1479 targetImplementationVersion option is also supported for the
1480 benefit of old applications.)
1481 </entry><entry>none</entry></row>
1483 databaseName</entry><entry>One or more database names
1484 separated by character plus (<literal>+</literal>), which to
1485 be used by subsequent search requests on this Connection.
1486 </entry><entry>Default</entry></row>
1488 piggyback</entry><entry>True (1) if piggyback should be
1489 used in searches; false (0) if not.
1490 </entry><entry>1</entry></row>
1492 smallSetUpperBound</entry><entry>If hits is less than or equal to this
1493 value, then target will return all records using small element set name
1494 </entry><entry>0</entry></row>
1496 largeSetLowerBound</entry><entry>If hits is greater than this
1497 value, the target will return no records.
1498 </entry><entry>1</entry></row>
1500 mediumSetPresentNumber</entry><entry>This value represents
1501 the number of records to be returned as part of a search when when
1502 hits is less than or equal to large set lower bound and if hits
1503 is greater than small set upper bound.
1504 </entry><entry>0</entry></row>
1506 smallSetElementSetName</entry><entry>
1507 The element set name to be used for small result sets.
1508 </entry><entry>none</entry></row>
1510 mediumSetElementSetName</entry><entry>
1511 The element set name to be for medium-sized result sets.
1512 </entry><entry>none</entry></row>
1514 init_opt_search, init_opt_present, init_opt_delSet, etc.</entry><entry>
1515 After a successful Init, these options may be interrogated to
1516 discover whether the server claims to support the specified
1518 </entry><entry>none</entry></row>
1520 <entry>sru</entry><entry>
1521 SRU/Solr transport type. Must be either <literal>soap</literal>,
1522 <literal>get</literal>, <literal>post</literal>, or
1523 <literal>solr</literal>.
1524 </entry><entry>soap</entry></row>
1526 sru_version</entry><entry>
1527 SRU/SRW version. Should be <literal>1.1</literal>, or
1528 <literal>1.2</literal>. This is , prior to connect, the version
1529 to offer (highest version). And following connect (in fact
1530 first operation), holds the negotiated version with the server
1531 (same or lower version).
1532 </entry><entry>1.2</entry></row>
1533 <row id="zoom.facets.option"><entry>
1534 facets</entry><entry>
1535 Requested or recommend facets may be given before a search is sent.
1536 The value of this setting is described in <xref linkend="facets"/>
1537 For inspection of the facets returned, refer to the functions
1538 described in <xref linkend="zoom.facets"/>.
1539 </entry><entry>none</entry></row>
1541 apdulog</entry><entry>
1542 If set to a true value such as "1", a log of low-level
1543 protocol packets is emitted on standard error stream. This
1544 can be very useful for debugging.
1545 </entry><entry>0</entry></row>
1547 saveAPDU</entry><entry>
1548 If set to a true value such as "1", a log of low-level
1549 protocol packets is saved. The log can be retrieved by reading
1550 option APDU. Setting saveAPDU always has the side effect of
1551 resetting the currently saved log. This setting is
1552 <emphasis>write-only</emphasis>. If read, NULL will be returned.
1553 It is only recognized in
1554 <function>ZOOM_connection_option_set</function>.
1555 </entry><entry>0</entry></row>
1558 Returns the log of protocol packets. Will be empty if logging
1559 is not enabled (see saveAPDU above). This setting is
1560 <emphasis>read-only</emphasis>. It is only recognized if used
1561 in call to <function>ZOOM_connection_option_get</function> or
1562 <function>ZOOM_connection_option_getl</function>.
1563 </entry><entry></entry></row>
1565 memcached</entry><entry>
1566 If given and non-empty,
1567 <ulink url="&url.libmemcached;">libMemcached</ulink>
1568 will be configured for the connection.
1569 This option is inspected by ZOOM when a connection is established.
1570 If the <literal>memcached</literal> option is given
1571 and YAZ is compiled without libMemcached support, an internal
1572 diagnostic (10018) will be thrown.
1573 libMemcached support is available for YAZ 5.0.13 or later. If this
1574 option is supplied for an earlier version of YAZ, it is
1575 <emphasis>ignored</emphasis>.
1576 The value of this option is a list options - each is of the
1577 form <literal>--name=value</literal>.
1578 Option <literal>--server=</literal>host[:port] specifies a memcached
1579 server. It may be repeated for multiple memcached servers.
1580 Option <literal>--expire=</literal>seconds sets expiry time in seconds
1581 for how long result sets are to be cached.
1582 </entry><entry>none</entry></row>
1584 redis</entry><entry>
1585 If given and non-empty,
1586 a <ulink url="&url.redis;">redis</ulink> context will be created
1588 This option is inspected by ZOOM when a connection is established.
1589 If the <literal>redis</literal> option is given
1590 and YAZ is compiled without redis support, an internal
1591 diagnostic (10018) will be thrown.
1592 redis support is available for YAZ 5.2.0 or later. If this
1593 option is supplied for an earlier version of YAZ, it is
1594 <emphasis>ignored</emphasis>.
1595 The value of this option is a set options, similar to that
1596 of the memcached setting. At this stage only --server=host[:port]
1597 and --expire=seconds is supported.
1598 </entry><entry>none</entry></row>
1603 If either option <literal>lang</literal> or <literal>charset</literal>
1605 <ulink url="&url.z39.50.charneg;">
1606 Character Set and Language Negotiation</ulink> is in effect.
1609 int ZOOM_connection_error(ZOOM_connection c, const char **cp,
1610 const char **addinfo);
1611 int ZOOM_connection_error_x(ZOOM_connection c, const char **cp,
1612 const char **addinfo, const char **dset);
1615 Function <function>ZOOM_connection_error</function> checks for
1616 errors for the last operation(s) performed. The function returns
1617 zero if no errors occurred; non-zero otherwise indicating the error.
1618 Pointers <parameter>cp</parameter> and <parameter>addinfo</parameter>
1619 holds messages for the error and additional-info if passed as
1620 non-<literal>NULL</literal>. Function
1621 <function>ZOOM_connection_error_x</function> is an extended version
1622 of <function>ZOOM_connection_error</function> that is capable of
1623 returning name of diagnostic set in <parameter>dset</parameter>.
1625 <sect2 id="zoom-connection-z39.50">
1626 <title>Z39.50 Protocol behavior</title>
1628 The calls <function>ZOOM_connection_new</function> and
1629 <function>ZOOM_connection_connect</function> establishes a TCP/IP
1630 connection and sends an Initialize Request to the target if
1631 possible. In addition, the calls waits for an Initialize Response
1632 from the target and the result is inspected (OK or rejected).
1635 If <literal>proxy</literal> is set then the client will establish
1636 a TCP/IP connection with the peer as specified by the
1637 <literal>proxy</literal> host and the hostname as part of the
1638 connect calls will be set as part of the Initialize Request.
1639 The proxy server will then "forward" the PDU's transparently
1640 to the target behind the proxy.
1643 For the authentication parameters, if option <literal>user</literal>
1644 is set and both options <literal>group</literal> and
1645 <literal>pass</literal> are unset, then Open style
1646 authentication is used (Version 2/3) in which case the username
1647 is usually followed by a slash, then by a password.
1648 If either <literal>group</literal>
1649 or <literal>pass</literal> is set then idPass authentication
1650 (Version 3 only) is used. If none of the options are set, no
1651 authentication parameters are set as part of the Initialize Request
1655 When option <literal>async</literal> is 1, it really means that
1656 all network operations are postponed (and queued) until the
1657 function <literal>ZOOM_event</literal> is invoked. When doing so
1658 it doesn't make sense to check for errors after
1659 <literal>ZOOM_connection_new</literal> is called since that
1660 operation "connecting - and init" is still incomplete and the
1661 API cannot tell the outcome (yet).
1664 <sect2 id="zoom.sru.init.behavior">
1665 <title>SRU/Solr Protocol behavior</title>
1667 The HTTP based protocols (SRU, SRW, Solr) doesn't feature an
1668 Inititialize Request, so the connection phase merely establishes a
1669 TCP/IP connection with the HTTP server.
1671 <para>Most of the ZOOM connection options do not
1672 affect SRU/Solr and they are ignored. However, future versions
1673 of &yaz; might honor <literal>implementationName</literal> and
1674 put that as part of User-Agent header for HTTP requests.
1677 The <literal>charset</literal> is used in the Content-Type header
1681 Setting <literal>authentcationMode</literal> specifies how
1682 authentication parameters are encoded for HTTP. The default is
1683 "<literal>basic</literal>" where <literal>user</literal> and
1684 <literal>password</literal> are encoded by using HTTP basic
1688 If <literal>authentcationMode</literal> is "<literal>url</literal>", then
1689 user and password are encoded in the URL by parameters
1690 <literal>x-username</literal> and <literal>x-password</literal> as
1691 given by the SRU standard.
1695 <sect1 id="zoom.query">
1696 <title>Queries</title>
1698 Query objects represents queries.
1701 ZOOM_query ZOOM_query_create(void);
1703 void ZOOM_query_destroy(ZOOM_query q);
1705 int ZOOM_query_prefix(ZOOM_query q, const char *str);
1707 int ZOOM_query_cql(ZOOM_query s, const char *str);
1709 int ZOOM_query_sortby(ZOOM_query q, const char *criteria);
1711 int ZOOM_query_sortby2(ZOOM_query q, const char *strategy,
1712 const char *criteria);
1715 Create query objects using <function>ZOOM_query_create</function>
1716 and destroy them by calling <function>ZOOM_query_destroy</function>.
1717 RPN-queries can be specified in <link linkend="PQF">PQF</link>
1718 notation by using the
1719 function <function>ZOOM_query_prefix</function>.
1720 The <function>ZOOM_query_cql</function> specifies a CQL
1721 query to be sent to the server/target.
1722 More query types will be added in future versions of &yaz;, such as
1723 <link linkend="CCL">CCL</link> to RPN-mapping, native CCL query,
1724 etc. In addition to a search, a sort criteria may be set. Function
1725 <function>ZOOM_query_sortby</function> enables Z39.50 sorting and
1726 it takes sort criteria using the same string notation as
1727 yaz-client's <link linkend="sortspec">sort command</link>.
1729 <para id="zoom.query.sortby2">
1730 <function>ZOOM_query_sortby2</function> is similar to
1731 <function>ZOOM_query_sortby</function> but allows a strategy for
1732 sorting. The reason for the strategy parameter is that some
1733 protocols offers multiple ways of performing sorting.
1734 For example, Z39.50 has the standard sort, which is performed after
1735 search on an existing result set.
1736 It's also possible to use CQL in Z39.50 as the query type and use
1737 CQL's SORTBY keyword. Finally, Index Data's
1738 Zebra server also allows sorting to be specified as part of RPN (Type 7).
1740 <table id="zoom-sort-strategy" frame="top">
1741 <title>ZOOM sort strategy</title>
1743 <colspec colwidth="2*" colname="name"/>
1744 <colspec colwidth="5*" colname="description"/>
1748 <entry>Description</entry>
1753 <entry>z39.50</entry><entry>Z39.50 resultset sort</entry>
1756 <entry>type7</entry><entry>Sorting embedded in RPN(Type-7)</entry>
1759 <entry>cql</entry><entry>CQL SORTBY</entry>
1762 <entry>sru11</entry><entry>SRU sortKeys parameter</entry>
1765 <entry>solr</entry><entry>Solr sort</entry>
1768 <entry>embed</entry><entry>type7 for Z39.50, cql for SRU,
1769 solr for Solr protocol</entry>
1775 <sect1 id="zoom.resultsets"><title>Result sets</title>
1777 The result set object is a container for records returned from
1781 ZOOM_resultset ZOOM_connection_search(ZOOM_connection, ZOOM_query q);
1783 ZOOM_resultset ZOOM_connection_search_pqf(ZOOM_connection c,
1785 void ZOOM_resultset_destroy(ZOOM_resultset r);
1788 Function <function>ZOOM_connection_search</function> creates
1789 a result set given a connection and query.
1790 Destroy a result set by calling
1791 <function>ZOOM_resultset_destroy</function>.
1792 Simple clients may using PQF only may use function
1793 <function>ZOOM_connection_search_pqf</function> in which case
1794 creating query objects is not necessary.
1797 void ZOOM_resultset_option_set(ZOOM_resultset r,
1798 const char *key, const char *val);
1800 const char *ZOOM_resultset_option_get(ZOOM_resultset r, const char *key);
1802 size_t ZOOM_resultset_size(ZOOM_resultset r);
1805 Functions <function>ZOOM_resultset_options_set</function> and
1806 <function>ZOOM_resultset_get</function> sets and gets an option
1807 for a result set similar to <function>ZOOM_connection_option_get</function>
1808 and <function>ZOOM_connection_option_set</function>.
1811 The number of hits also called result-count is returned by
1812 function <function>ZOOM_resultset_size</function>.
1814 <table id="zoom.resultset.options"
1815 frame="top"><title>ZOOM Result set Options</title>
1817 <colspec colwidth="4*" colname="name"></colspec>
1818 <colspec colwidth="7*" colname="description"></colspec>
1819 <colspec colwidth="2*" colname="default"></colspec>
1822 <entry>Option</entry>
1823 <entry>Description</entry>
1824 <entry>Default</entry>
1829 start</entry><entry>Offset of first record to be
1830 retrieved from target. First record has offset 0 unlike the
1831 protocol specifications where first record has position 1.
1832 This option affects ZOOM_resultset_search and
1833 ZOOM_resultset_search_pqf and must be set before any of
1834 these functions are invoked. If a range of
1835 records must be fetched manually after search,
1836 function ZOOM_resultset_records should be used.
1837 </entry><entry>0</entry></row>
1839 count</entry><entry>Number of records to be retrieved.
1840 This option affects ZOOM_resultset_search and
1841 ZOOM_resultset_search_pqf and must be set before any of
1842 these functions are invoked.
1843 </entry><entry>0</entry></row>
1845 presentChunk</entry><entry>The number of records to be
1846 requested from the server in each chunk (present request). The
1847 value 0 means to request all the records in a single chunk.
1848 (The old <literal>step</literal>
1849 option is also supported for the benefit of old applications.)
1850 </entry><entry>0</entry></row>
1852 elementSetName</entry><entry>Element-Set name of records.
1853 Most targets should honor element set name <literal>B</literal>
1854 and <literal>F</literal> for brief and full respectively.
1855 </entry><entry>none</entry></row>
1857 preferredRecordSyntax</entry><entry>Preferred Syntax, such as
1858 <literal>USMARC</literal>, <literal>SUTRS</literal>, etc.
1859 </entry><entry>none</entry></row>
1861 schema</entry><entry>Schema for retrieval, such as
1862 <literal>Gils-schema</literal>, <literal>Geo-schema</literal>, etc.
1863 </entry><entry>none</entry></row>
1865 setname</entry><entry>Name of Result Set (Result Set ID).
1866 If this option isn't set, the ZOOM module will automatically
1867 allocate a result set name.
1868 </entry><entry>default</entry></row>
1870 rpnCharset</entry><entry>Character set for RPN terms.
1871 If this is set, ZOOM C will assume that the ZOOM application is
1872 running UTF-8. Terms in RPN queries are then converted to the
1873 rpnCharset. If this is unset, ZOOM C will not assume any encoding
1874 of RPN terms and no conversion is performed.
1875 </entry><entry>none</entry></row>
1880 For servers that support Search Info report, the following
1881 options may be read using <function>ZOOM_resultset_get</function>.
1882 This detailed information is read after a successful search has
1886 This information is a list of of items, where each item is
1887 information about a term or subquery. All items in the list
1889 <literal>SearchResult.</literal><replaceable>no</replaceable>
1890 where no presents the item number (0=first, 1=second).
1891 Read <literal>searchresult.size</literal> to determine the
1894 <table id="zoom.search.info.report.options"
1895 frame="top"><title>Search Info Report Options</title>
1897 <colspec colwidth="4*" colname="name"></colspec>
1898 <colspec colwidth="7*" colname="description"></colspec>
1901 <entry>Option</entry>
1902 <entry>Description</entry>
1907 <entry>searchresult.size</entry>
1909 number of search result entries. This option is-nonexistant
1910 if no entries are returned by the server.
1914 <entry>searchresult.<replaceable>no</replaceable>.id</entry>
1915 <entry>sub query ID</entry>
1918 <entry>searchresult.<replaceable>no</replaceable>.count</entry>
1919 <entry>result count for item (number of hits)</entry>
1922 <entry>searchresult.<replaceable>no</replaceable>.subquery.term</entry>
1923 <entry>subquery term</entry>
1927 searchresult.<replaceable>no</replaceable>.interpretation.term
1929 <entry>interpretation term</entry>
1933 searchresult.<replaceable>no</replaceable>.recommendation.term
1935 <entry>recommendation term</entry>
1940 <sect2 id="zoom.z3950.resultset.sort">
1941 <title>Z39.50 Result-set Sort</title>
1943 void ZOOM_resultset_sort(ZOOM_resultset r,
1944 const char *sort_type, const char *sort_spec);
1946 int ZOOM_resultset_sort1(ZOOM_resultset r,
1947 const char *sort_type, const char *sort_spec);
1950 <function>ZOOM_resultset_sort</function> and
1951 <function>ZOOM_resultset_sort1</function> both sort an existing
1952 result-set. The sort_type parameter is not use. Set it to "yaz".
1953 The sort_spec is same notation as ZOOM_query_sortby and identical
1954 to that offered by yaz-client's
1955 <link linkend="sortspec">sort command</link>.
1958 These functions only work for Z39.50. Use the more generic utility
1959 <link linkend="zoom.query.sortby2">
1960 <function>ZOOM_query_sortby2</function></link>
1961 for other protocols (and even Z39.50).
1964 <sect2 id="zoom.z3950.resultset.behavior">
1965 <title>Z39.50 Protocol behavior</title>
1967 The creation of a result set involves at least a SearchRequest
1968 - SearchResponse protocol handshake. Following that, if a sort
1969 criteria was specified as part of the query, a SortRequest -
1970 SortResponse handshake takes place. Note that it is necessary to
1971 perform sorting before any retrieval takes place, so no records will
1972 be returned from the target as part of the SearchResponse because these
1973 would be unsorted. Hence, piggyback is disabled when sort criteria
1974 are set. Following Search - and a possible sort - Retrieval takes
1975 place - as one or more Present Requests/Response pairs being
1979 The API allows for two different modes for retrieval. A high level
1980 mode which is somewhat more powerful and a low level one.
1981 The low level is enabled when searching on a Connection object
1982 for which the settings
1983 <literal>smallSetUpperBound</literal>,
1984 <literal>mediumSetPresentNumber</literal> and
1985 <literal>largeSetLowerBound</literal> are set. The low level mode
1986 thus allows you to precisely set how records are returned as part
1987 of a search response as offered by the Z39.50 protocol.
1988 Since the client may be retrieving records as part of the
1989 search response, this mode doesn't work well if sorting is used.
1992 The high-level mode allows you to fetch a range of records from
1993 the result set with a given start offset. When you use this mode
1994 the client will automatically use piggyback if that is possible
1995 with the target and perform one or more present requests as needed.
1996 Even if the target returns fewer records as part of a present response
1997 because of a record size limit, etc. the client will repeat sending
1998 present requests. As an example, if option <literal>start</literal>
1999 is 0 (default) and <literal>count</literal> is 4, and
2000 <literal>piggyback</literal> is 1 (default) and no sorting criteria
2001 is specified, then the client will attempt to retrieve the 4
2002 records as part the search response (using piggyback). On the other
2003 hand, if either <literal>start</literal> is positive or if
2004 a sorting criteria is set, or if <literal>piggyback</literal>
2005 is 0, then the client will not perform piggyback but send Present
2009 If either of the options <literal>mediumSetElementSetName</literal> and
2010 <literal>smallSetElementSetName</literal> are unset, the value
2011 of option <literal>elementSetName</literal> is used for piggyback
2012 searches. This means that for the high-level mode you only have
2013 to specify one elementSetName option rather than three.
2016 <sect2 id="zoom.sru.resultset.behavior">
2017 <title>SRU Protocol behavior</title>
2019 Current version of &yaz; does not take advantage of a result set id
2020 returned by the SRU server. Future versions might do, however.
2021 Since, the ZOOM driver does not save result set IDs any
2022 present (retrieval) is transformed to a SRU SearchRetrieveRequest
2023 with same query but, possibly, different offsets.
2026 Option <literal>schema</literal> specifies SRU schema
2027 for retrieval. However, options <literal>elementSetName</literal> and
2028 <literal>preferredRecordSyntax</literal> are ignored.
2031 Options <literal>start</literal> and <literal>count</literal>
2032 are supported by SRU.
2033 The remaining options
2034 <literal>piggyback</literal>,
2035 <literal>smallSetUpperBound</literal>,
2036 <literal>largeSetLowerBound</literal>,
2037 <literal>mediumSetPresentNumber</literal>,
2038 <literal>mediumSetElementSetName</literal>,
2039 <literal>smallSetElementSetName</literal> are
2043 SRU supports CQL queries, <emphasis>not</emphasis> PQF.
2044 If PQF is used, however, the PQF query is transferred anyway
2045 using non-standard element <literal>pQuery</literal> in
2046 SRU SearchRetrieveRequest.
2049 Solr queries has to be done in Solr query format.
2052 Unfortunately, SRU or Solr does not define a database setting. Hence,
2053 <literal>databaseName</literal> is unsupported and ignored.
2054 However, the path part in host parameter for functions
2055 <function>ZOOM_connecton_new</function> and
2056 <function>ZOOM_connection_connect</function> acts as a
2057 database (at least for the &yaz; SRU server).
2061 <sect1 id="zoom.records">
2062 <title>Records</title>
2064 A record object is a retrieval record on the client side -
2065 created from result sets.
2068 void ZOOM_resultset_records(ZOOM_resultset r,
2070 size_t start, size_t count);
2071 ZOOM_record ZOOM_resultset_record(ZOOM_resultset s, size_t pos);
2073 const char *ZOOM_record_get(ZOOM_record rec, const char *type,
2076 int ZOOM_record_error(ZOOM_record rec, const char **msg,
2077 const char **addinfo, const char **diagset);
2079 ZOOM_record ZOOM_record_clone(ZOOM_record rec);
2081 void ZOOM_record_destroy(ZOOM_record rec);
2084 References to temporary records are returned by functions
2085 <function>ZOOM_resultset_records</function> or
2086 <function>ZOOM_resultset_record</function>.
2089 If a persistent reference to a record is desired
2090 <function>ZOOM_record_clone</function> should be used.
2091 It returns a record reference that should be destroyed
2092 by a call to <function>ZOOM_record_destroy</function>.
2095 A single record is returned by function
2096 <function>ZOOM_resultset_record</function> that takes a
2097 position as argument. First record has position zero.
2098 If no record could be obtained <literal>NULL</literal> is returned.
2101 Error information for a record can be checked with
2102 <function>ZOOM_record_error</function> which returns non-zero
2103 (error code) if record is in error, called <emphasis>Surrogate
2104 Diagnostics</emphasis> in Z39.50.
2107 Function <function>ZOOM_resultset_records</function> retrieves
2108 a number of records from a result set. Parameter <literal>start</literal>
2109 and <literal>count</literal> specifies the range of records to
2110 be returned. Upon completion array
2111 <literal>recs[0], ..recs[count-1]</literal>
2112 holds record objects for the records. The array of records
2113 <literal>recs</literal> should be allocated prior the call
2114 <function>ZOOM_resultset_records</function>. Note that for those
2115 records that couldn't be retrieved from the target
2116 <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
2118 <para id="zoom.record.get">
2119 In order to extract information about a single record,
2120 <function>ZOOM_record_get</function> is provided. The
2121 function returns a pointer to certain record information. The
2122 nature (type) of the pointer depends on the parameter,
2123 <parameter>type</parameter>.
2126 The <parameter>type</parameter> is a string of the format:
2129 <replaceable>format</replaceable>[;charset=<replaceable>from</replaceable>[/<replaceable>opacfrom</replaceable>][,<replaceable>to</replaceable>]][;format=<replaceable>v</replaceable>][;base64=<replaceable>xpath</replaceable>]
2132 If <literal>charset</literal> is given, then <replaceable>from</replaceable>
2133 specifies the character set of the record in its original form
2134 (as returned by the server), <replaceable>to</replaceable> specifies
2135 the output (returned) character set encoding.
2136 If <replaceable>to</replaceable> is omitted, then UTF-8 is assumed.
2137 If charset is not given, then no character set conversion takes place.
2138 OPAC records may be returned in a different
2139 set from the bibliographic MARC record. If this is this the case,
2140 <replaceable>opacfrom</replaceable> should be set to the character set
2141 of the OPAC record part.
2145 The <literal>format</literal> is generic but can only be used to
2146 specify XML indentation when the value <replaceable>v</replaceable>
2147 is 1 (<literal>format=1</literal>).
2150 The <literal>base64</literal> allows a full record to be extracted
2151 from base64-encoded string in an XML document.
2155 Specifying the OPAC record character set requires YAZ 4.1.5 or later.
2158 Specifying the base64 parameter requires YAZ 4.2.35 or later.
2162 The format argument controls whether record data should be XML
2163 pretty-printed (post process operation).
2164 It is enabled only if format value <replaceable>v</replaceable> is
2165 <literal>1</literal> and the record content is XML well-formed.
2168 In addition, for certain types, the length
2169 <literal>len</literal> passed will be set to the size in bytes of
2170 the returned information.
2173 The following are the supported values for <replaceable>form</replaceable>.
2175 <varlistentry><term><literal>database</literal></term>
2176 <listitem><para>Database of record is returned
2177 as a C null-terminated string. Return type
2178 <literal>const char *</literal>.
2181 <varlistentry><term><literal>syntax</literal></term>
2182 <listitem><para>The transfer syntax of the record is returned
2183 as a C null-terminated string containing the symbolic name of
2184 the record syntax, e.g. <literal>Usmarc</literal>. Return type
2186 <literal>const char *</literal>.
2189 <varlistentry><term><literal>schema</literal></term>
2190 <listitem><para>The schema of the record is returned
2191 as a C null-terminated string. Return type is
2192 <literal>const char *</literal>.
2195 <varlistentry><term><literal>render</literal></term>
2196 <listitem><para>The record is returned in a display friendly
2197 format. Upon completion buffer is returned
2198 (type <literal>const char *</literal>) and length is stored in
2199 <literal>*len</literal>.
2202 <varlistentry><term><literal>raw</literal></term>
2203 <listitem><para>The record is returned in the internal
2204 YAZ specific format. For GRS-1, Explain, and others, the
2205 raw data is returned as type
2206 <literal>Z_External *</literal> which is just the type for
2207 the member <literal>retrievalRecord</literal> in
2208 type <literal>NamePlusRecord</literal>.
2209 For SUTRS and octet aligned record (including all MARCs) the
2210 octet buffer is returned and the length of the buffer.
2213 <varlistentry><term><literal>xml</literal></term>
2214 <listitem><para>The record is returned in XML if possible.
2215 SRU, Solr and Z39.50 records with transfer syntax XML are
2216 returned verbatim. MARC records are returned in
2217 <ulink url="&url.marcxml;">
2220 (converted from ISO2709 to MARCXML by YAZ).
2221 OPAC records are also converted to XML and the
2222 bibliographic record is converted to MARCXML (when possible).
2223 GRS-1 records are not supported for this form.
2224 Upon completion, the XML buffer is returned
2225 (type <literal>const char *</literal>) and length is stored in
2226 <literal>*len</literal>.
2229 <varlistentry><term><literal>opac</literal></term>
2230 <listitem><para>OPAC information for record is returned in XML
2231 if an OPAC record is present at the position given. If no
2232 OPAC record is present, a NULL pointer is returned.
2235 <varlistentry><term><literal>txml</literal></term>
2236 <listitem><para>The record is returned in TurboMARC if possible.
2237 SRU and Z39.50 records with transfer syntax XML are
2238 returned verbatim. MARC records are returned in
2239 <link linkend="tools.turbomarc">
2242 (converted from ISO2709 to TurboMARC by YAZ).
2243 Upon completion, the XML buffer is returned
2244 (type <literal>const char *</literal>) and length is stored in
2245 <literal>*len</literal>.
2248 <varlistentry><term><literal>json</literal></term>
2249 <listitem><para>Like xml, but MARC records are converted to
2250 <ulink url="&url.marc_in_json;">MARC-in-JSON</ulink>.
2258 <ulink url="&url.marc21;">MARC21</ulink>
2260 <ulink url="&url.marc8;">MARC-8</ulink>
2261 character set encoding.
2262 An application that wishes to display in Latin-1 would use
2264 render; charset=marc8,iso-8859-1
2267 <sect2 id="zoom.z3950.record.behavior">
2268 <title>Z39.50 Protocol behavior</title>
2270 The functions <function>ZOOM_resultset_record</function> and
2271 <function>ZOOM_resultset_records</function> inspects the client-side
2272 record cache. Records not found in cache are fetched using
2274 The functions may block (and perform network I/O) - even though option
2275 <literal>async</literal> is 1, because they return records objects.
2276 (and there's no way to return records objects without retrieving them!).
2279 There is a trick, however, in the usage of function
2280 <function>ZOOM_resultset_records</function> that allows for
2281 delayed retrieval (and makes it non-blocking). By using
2282 a null pointer for <parameter>recs</parameter> you're indicating
2283 you're not interested in getting records objects
2284 <emphasis>now</emphasis>.
2287 <sect2 id="zoom.sru.record.behavior">
2288 <title>SRU/Solr Protocol behavior</title>
2290 The ZOOM driver for SRU/Solr treats records returned by a SRU/Solr server
2291 as if they where Z39.50 records with transfer syntax XML and
2292 no element set name or database name.
2296 <sect1 id="zoom.facets"><title>Facets</title>
2298 Facet operations is not part of the official ZOOM specification, but
2299 is an Index Data extension for YAZ-based Z39.50 targets,
2300 <ulink url="&url.solr;">Solr</ulink> and SRU 2.0 targets.
2302 Facets may be requestd by the
2303 <link linkend="zoom.facets.option">facets</link> option before a
2305 For inspection of the returned facets, the following functions are
2309 ZOOM_facet_field *ZOOM_resultset_facets(ZOOM_resultset r);
2311 ZOOM_facet_field ZOOM_resultset_get_facet_field(ZOOM_resultset r,
2312 const char *facet_name);
2314 ZOOM_facet_field ZOOM_resultset_get_facet_field_by_index(ZOOM_resultset r,
2317 size_t ZOOM_resultset_facets_size(ZOOM_resultset r);
2319 const char *ZOOM_facet_field_name(ZOOM_facet_field facet_field);
2321 size_t ZOOM_facet_field_term_count(ZOOM_facet_field facet_field);
2323 const char *ZOOM_facet_field_get_term(ZOOM_facet_field facet_field,
2324 size_t idx, int *freq);
2327 References to temporary structures are returned by all functions.
2328 They are only valid as long the Result set is valid.
2329 <function>ZOOM_resultset_get_facet_field</function> or
2330 <function>ZOOM_resultset_get_facet_field_by_index</function>.
2331 <function>ZOOM_resultset_facets</function>.
2332 <function>ZOOM_facet_field_name</function>.
2333 <function>ZOOM_facet_field_get_term</function>.
2335 <para id="zoom.resultset.get_facet_field">
2336 A single Facet field is returned by function
2337 <function>ZOOM_resultset_get_facet_field</function> or
2338 <function>ZOOM_resultset_get_facet_field_by_index</function> that takes
2339 a result set and facet name or positive index respectively. First
2340 facet has position zero. If no facet could be obtained (invalid name
2341 or index out of bounds) <literal>NULL</literal> is returned.
2343 <para id="zoom.resultset.facets">
2344 An array of facets field can be returned by
2345 <function>ZOOM_resultset_facets</function>. The length of the array is
2346 given by <function>ZOOM_resultset_facets_size</function>. The array is
2347 zero-based and last entry will be at
2348 <function>ZOOM_resultset_facets_size(result_set)</function>-1.
2350 <para id="zoom.resultset.facets_names">
2351 It is possible to interate over facets by name, by calling
2352 <function>ZOOM_resultset_facets_names</function>.
2353 This will return an const array of char * where each string can be used
2354 as parameter for <function>ZOOM_resultset_get_facet_field</function>.
2357 Function <function>ZOOM_facet_field_name</function> gets the request
2358 facet name from a returned facet field.
2361 Function <function>ZOOM_facet_field_get_term</function> returns the
2362 idx'th term and term count for a facet field.
2363 Idx must between 0 and
2364 <function>ZOOM_facet_field_term_count</function>-1, otherwise the
2365 returned reference will be <literal>NULL</literal>. On a valid idx, the
2366 value of the freq reference will be the term count.
2367 The <literal>freq</literal> parameter must be valid pointer to integer.
2370 <sect1 id="zoom.scan"><title>Scan</title>
2372 This section describes an interface for Scan. Scan is not an
2373 official part of the ZOOM model yet. The result of a scan operation
2374 is the <literal>ZOOM_scanset</literal> which is a set of terms
2375 returned by a target.
2379 The Scan interface is supported for both Z39.50, SRU and Solr.
2383 ZOOM_scanset ZOOM_connection_scan(ZOOM_connection c,
2384 const char *startpqf);
2386 ZOOM_scanset ZOOM_connection_scan1(ZOOM_connection c,
2389 size_t ZOOM_scanset_size(ZOOM_scanset scan);
2391 const char *ZOOM_scanset_term(ZOOM_scanset scan, size_t pos,
2392 size_t *occ, size_t *len);
2394 const char *ZOOM_scanset_display_term(ZOOM_scanset scan, size_t pos,
2395 size_t *occ, size_t *len);
2397 void ZOOM_scanset_destroy(ZOOM_scanset scan);
2399 const char *ZOOM_scanset_option_get(ZOOM_scanset scan,
2402 void ZOOM_scanset_option_set(ZOOM_scanset scan, const char *key,
2406 The scan set is created by function
2407 <function>ZOOM_connection_scan</function> which performs a scan
2408 operation on the connection using the specified
2409 <parameter>startpqf</parameter>.
2410 If the operation was successful, the size of the scan set can be
2411 retrieved by a call to <function>ZOOM_scanset_size</function>.
2412 Like result sets, the items are numbered 0,..size-1.
2413 To obtain information about a particular scan term, call function
2414 <function>ZOOM_scanset_term</function>. This function takes
2415 a scan set offset <literal>pos</literal> and returns a pointer
2416 to a <emphasis>raw term</emphasis> or <literal>NULL</literal> if
2418 If present, the <literal>occ</literal> and <literal>len</literal>
2419 are set to the number of occurrences and the length
2420 of the actual term respectively.
2421 <function>ZOOM_scanset_display_term</function> is similar to
2422 <function>ZOOM_scanset_term</function> except that it returns
2423 the <emphasis>display term</emphasis> rather than the raw term.
2424 In a few cases, the term is different from display term. Always
2425 use the display term for display and the raw term for subsequent
2426 scan operations (to get more terms, next scan result, etc).
2429 A scan set may be freed by a call to function
2430 <function>ZOOM_scanset_destroy</function>.
2431 Functions <function>ZOOM_scanset_option_get</function> and
2432 <function>ZOOM_scanset_option_set</function> retrieves and sets
2433 an option respectively.
2436 The <parameter>startpqf</parameter> is a subset of PQF, namely
2437 the Attributes+Term part. Multiple <literal>@attr</literal> can
2438 be used. For example to scan in title (complete) phrases:
2440 @attr 1=4 @attr 6=2 "science o"
2444 The <function>ZOOM_connecton_scan1</function> is a newer and
2445 more generic alternative to <function>ZOOM_connection_scan</function>
2446 which allows to use both CQL and PQF for Scan.
2448 <table frame="top" id="zoom.scanset.options">
2449 <title>ZOOM Scan Set Options</title>
2451 <colspec colwidth="4*" colname="name"></colspec>
2452 <colspec colwidth="7*" colname="description"></colspec>
2453 <colspec colwidth="2*" colname="default"></colspec>
2456 <entry>Option</entry>
2457 <entry>Description</entry>
2458 <entry>Default</entry>
2463 number</entry><entry>Number of Scan Terms requested in next scan.
2464 After scan it holds the actual number of terms returned.
2465 </entry><entry>20</entry></row>
2467 position</entry><entry>Preferred Position of term in response
2468 in next scan; actual position after completion of scan.
2469 </entry><entry>1</entry></row>
2471 stepSize</entry><entry>Step Size
2472 </entry><entry>0</entry></row>
2474 scanStatus</entry><entry>An integer indicating the Scan Status
2476 </entry><entry>0</entry></row>
2478 rpnCharset</entry><entry>Character set for RPN terms.
2479 If this is set, ZOOM C will assume that the ZOOM application is
2480 running UTF-8. Terms in RPN queries are then converted to the
2481 rpnCharset. If this is unset, ZOOM C will not assume any encoding
2482 of RPN terms and no conversion is performed.
2483 </entry><entry>none</entry></row>
2488 <sect1 id="zoom.extendedservices">
2489 <title>Extended Services</title>
2491 ZOOM offers an interface to a subset of the Z39.50 extended services
2492 as well as a few privately defined ones:
2497 Z39.50 Item Order (ILL).
2498 See <xref linkend="zoom.item.order"/>.
2503 Record Update. This allows a client to insert, modify or delete
2505 See <xref linkend="zoom.record.update"/>.
2510 Database Create. This a non-standard feature. Allows a client
2511 to create a database.
2512 See <xref linkend="zoom.database.create"/>.
2517 Database Drop. This a non-standard feature. Allows a client
2518 to delete/drop a database.
2519 See <xref linkend="zoom.database.drop"/>.
2524 Commit operation. This a non-standard feature. Allows a client
2525 to commit operations.
2526 See <xref linkend="zoom.commit"/>.
2529 <!-- all the ILL PDU options should go here too -->
2532 To create an extended service operation a <literal>ZOOM_package</literal>
2533 must be created. The operation is a five step operation. The
2534 package is created, package is configured by means of options,
2535 the package is send, result is inspected (by means of options),
2536 the package is destroyed.
2539 ZOOM_package ZOOM_connection_package(ZOOM_connection c,
2540 ZOOM_options options);
2542 const char *ZOOM_package_option_get(ZOOM_package p,
2544 void ZOOM_package_option_set(ZOOM_package p, const char *key,
2546 void ZOOM_package_send(ZOOM_package p, const char *type);
2548 void ZOOM_package_destroy(ZOOM_package p);
2551 The <function>ZOOM_connection_package</function> creates a
2552 package for the connection given using the options specified.
2555 Functions <function>ZOOM_package_option_get</function> and
2556 <function>ZOOM_package_option_set</function> gets and sets
2560 <function>ZOOM_package_send</function> sends
2561 the package the via connection specified in
2562 <function>ZOOM_connection_package</function>.
2563 The <parameter>type</parameter> specifies the actual extended service
2564 package type to be sent.
2566 <table frame="top" id="zoom.extendedservices.options">
2567 <title>Extended Service Common Options</title>
2569 <colspec colwidth="4*" colname="name"></colspec>
2570 <colspec colwidth="7*" colname="description"></colspec>
2571 <colspec colwidth="3*" colname="default"></colspec>
2574 <entry>Option</entry>
2575 <entry>Description</entry>
2576 <entry>Default</entry>
2581 <entry>package-name</entry>
2582 <entry>Extended Service Request package name. Must be specified
2583 as part of a request</entry>
2587 <entry>user-id</entry>
2588 <entry>User ID of Extended Service Package. Is a request option</entry>
2592 <entry>function</entry>
2594 Function of package - one of <literal>create</literal>,
2595 <literal>delete</literal>, <literal>modify</literal>. Is
2598 <entry><literal>create</literal></entry>
2601 <entry>waitAction</entry>
2603 Wait action for package. Possible values:
2604 <literal>wait</literal>, <literal>waitIfPossible</literal>,
2605 <literal>dontWait</literal> or <literal>dontReturnPackage</literal>.
2607 <entry><literal>waitIfPossible</literal></entry>
2610 <entry>targetReference</entry>
2612 Target Reference. This is part of the response as returned
2613 by the server. Read it after a successful operation.
2615 <entry><literal>none</literal></entry>
2620 <sect2 id="zoom.item.order">
2621 <title>Item Order</title>
2623 For Item Order, type must be set to <literal>itemorder</literal> in
2624 <function>ZOOM_package_send</function>.
2627 <table frame="top" id="zoom.item.order.options">
2628 <title>Item Order Options</title>
2630 <colspec colwidth="4*" colname="name"></colspec>
2631 <colspec colwidth="7*" colname="description"></colspec>
2632 <colspec colwidth="3*" colname="default"></colspec>
2635 <entry>Option</entry>
2636 <entry>Description</entry>
2637 <entry>Default</entry>
2642 <entry>contact-name</entry>
2643 <entry>ILL contact name</entry>
2647 <entry>contact-phone</entry>
2648 <entry>ILL contact phone</entry>
2652 <entry>contact-email</entry>
2653 <entry>ILL contact email</entry>
2657 <entry>itemorder-item</entry>
2658 <entry>Position for item (record) requested. An integer</entry>
2665 <sect2 id="zoom.record.update">
2666 <title>Record Update</title>
2668 For Record Update, type must be set to <literal>update</literal> in
2669 <function>ZOOM_package_send</function>.
2671 <table frame="top" id="zoom.record.update.options">
2672 <title>Record Update Options</title>
2674 <colspec colwidth="4*" colname="name"></colspec>
2675 <colspec colwidth="7*" colname="description"></colspec>
2676 <colspec colwidth="3*" colname="default"></colspec>
2679 <entry>Option</entry>
2680 <entry>Description</entry>
2681 <entry>Default</entry>
2686 <entry>action</entry>
2688 The update action. One of
2689 <literal>specialUpdate</literal>,
2690 <literal>recordInsert</literal>,
2691 <literal>recordReplace</literal>,
2692 <literal>recordDelete</literal>,
2693 <literal>elementUpdate</literal>.
2695 <entry><literal>specialUpdate (recordInsert for updateVersion=1 which does not support specialUpdate)</literal></entry>
2698 <entry>recordIdOpaque</entry>
2699 <entry>Opaque Record ID</entry>
2703 <entry>recordIdNumber</entry>
2704 <entry>Record ID number</entry>
2708 <entry>record</entry>
2709 <entry>The record itself</entry>
2713 <entry>recordOpaque</entry>
2714 <entry>Specifies an opaque record which is
2715 encoded as an ASN.1 ANY type with the OID as tiven by option
2716 <literal>syntax</literal> (see below).
2717 Option <literal>recordOpaque</literal> is an alternative
2718 to record - and <literal>record</literal> option (above) is
2719 ignored if recordOpaque is set. This option is only available in
2720 YAZ 3.0.35 and later and is meant to facilitate Updates with
2726 <entry>syntax</entry>
2727 <entry>The record syntax (transfer syntax). Is a string that
2728 is a known record syntax.
2730 <entry>no syntax</entry>
2733 <entry>databaseName</entry>
2734 <entry>Database from connection object</entry>
2735 <entry>Default</entry>
2738 <entry>correlationInfo.note</entry>
2739 <entry>Correlation Info Note (string)</entry>
2743 <entry>correlationInfo.id</entry>
2744 <entry>Correlation Info ID (integer)</entry>
2748 <entry>elementSetName</entry>
2749 <entry>Element Set for Record</entry>
2753 <entry>updateVersion</entry>
2754 <entry>Record Update version which holds one of the values
2755 1, 2 or 3. Each version has a distinct OID:
2757 (<ulink url="&url.z39.50.extupdate1;">first version</ulink>) ,
2759 (second version) and
2760 1.2.840.10003.9.5.1.1
2761 (<ulink url="&url.z39.50.extupdate3;">third and
2762 newest version</ulink>).
2772 <sect2 id="zoom.database.create"><title>Database Create</title>
2774 For Database Create, type must be set to <literal>create</literal> in
2775 <function>ZOOM_package_send</function>.
2778 <table frame="top" id="zoom.database.create.options">
2779 <title>Database Create Options</title>
2781 <colspec colwidth="4*" colname="name"></colspec>
2782 <colspec colwidth="7*" colname="description"></colspec>
2783 <colspec colwidth="3*" colname="default"></colspec>
2786 <entry>Option</entry>
2787 <entry>Description</entry>
2788 <entry>Default</entry>
2793 <entry>databaseName</entry>
2794 <entry>Database from connection object</entry>
2795 <entry>Default</entry>
2801 <sect2 id="zoom.database.drop">
2802 <title>Database Drop</title>
2804 For Database Drop, type must be set to <literal>drop</literal> in
2805 <function>ZOOM_package_send</function>.
2807 <table frame="top" id="zoom.database.drop.options">
2808 <title>Database Drop Options</title>
2810 <colspec colwidth="4*" colname="name"></colspec>
2811 <colspec colwidth="7*" colname="description"></colspec>
2812 <colspec colwidth="3*" colname="default"></colspec>
2815 <entry>Option</entry>
2816 <entry>Description</entry>
2817 <entry>Default</entry>
2822 <entry>databaseName</entry>
2823 <entry>Database from connection object</entry>
2824 <entry>Default</entry>
2830 <sect2 id="zoom.commit">
2831 <title>Commit Operation</title>
2833 For Commit, type must be set to <literal>commit</literal> in
2834 <function>ZOOM_package_send</function>.
2837 <sect2 id="zoom.extended.services.behavior">
2838 <title>Protocol behavior</title>
2840 All the extended services are Z39.50-only.
2844 The database create, drop and commit services are privately defined
2846 Refer to <filename>esadmin.asn</filename> in YAZ for the ASN.1
2852 <sect1 id="zoom.options">
2853 <title>Options</title>
2855 Most &zoom; objects provide a way to specify options to change behavior.
2856 From an implementation point of view a set of options is just like
2857 an associative array / hash.
2860 ZOOM_options ZOOM_options_create(void);
2862 ZOOM_options ZOOM_options_create_with_parent(ZOOM_options parent);
2864 void ZOOM_options_destroy(ZOOM_options opt);
2867 const char *ZOOM_options_get(ZOOM_options opt, const char *name);
2869 void ZOOM_options_set(ZOOM_options opt, const char *name,
2873 typedef const char *(*ZOOM_options_callback)
2874 (void *handle, const char *name);
2876 ZOOM_options_callback
2877 ZOOM_options_set_callback(ZOOM_options opt,
2878 ZOOM_options_callback c,
2882 <sect1 id="zoom.queryconversions">
2883 <title>Query conversions</title>
2885 int ZOOM_query_cql2rpn(ZOOM_query s, const char *cql_str,
2886 ZOOM_connection conn);
2888 int ZOOM_query_ccl2rpn(ZOOM_query s, const char *ccl_str,
2890 int *ccl_error, const char **error_string,
2894 <function>ZOOM_query_cql2rpn</function> translates the CQL string,
2895 client-side, into RPN which may be passed to the server.
2896 This is useful for server's that don't themselves
2897 support CQL, for which <function>ZOOM_query_cql</function> is useless.
2898 `conn' is used only as a place to stash diagnostics if compilation
2899 fails; if this information is not needed, a null pointer may be used.
2900 The CQL conversion is driven by option <literal>cqlfile</literal> from
2901 connection conn. This specifies a conversion file (eg pqf.properties)
2902 which <emphasis>must</emphasis> be present.
2905 <function>ZOOM_query_ccl2rpn</function> translates the CCL string,
2906 client-side, into RPN which may be passed to the server.
2907 The conversion is driven by the specification given by
2908 <literal>config</literal>. Upon completion 0 is returned on success; -1
2909 is returned on on failure. Om failure <literal>error_string</literal> and
2910 <literal>error_pos</literal> holds error message and position of
2911 first error in original CCL string.
2914 <sect1 id="zoom.events"><title>Events</title>
2916 If you're developing non-blocking applications, you have to deal
2920 int ZOOM_event(int no, ZOOM_connection *cs);
2923 The <function>ZOOM_event</function> executes pending events for
2924 a number of connections. Supply the number of connections in
2925 <literal>no</literal> and an array of connections in
2926 <literal>cs</literal> (<literal>cs[0] ... cs[no-1]</literal>).
2927 A pending event could be a sending a search, receiving a response,
2929 When an event has occurred for one of the connections, this function
2930 returns a positive integer <literal>n</literal> denoting that an event
2931 occurred for connection <literal>cs[n-1]</literal>.
2932 When no events are pending for the connections, a value of zero is
2934 To ensure that all outstanding requests are performed call this function
2935 repeatedly until zero is returned.
2938 If <function>ZOOM_event</function> returns and returns non-zero, the
2939 last event that occurred can be expected.
2942 int ZOOM_connection_last_event(ZOOM_connection cs);
2945 <function>ZOOM_connection_last_event</function> returns an event type
2946 (integer) for the last event.
2949 <table frame="top" id="zoom.event.ids">
2950 <title>ZOOM Event IDs</title>
2952 <colspec colwidth="4*" colname="name"></colspec>
2953 <colspec colwidth="7*" colname="description"></colspec>
2956 <entry>Event</entry>
2957 <entry>Description</entry>
2962 <entry>ZOOM_EVENT_NONE</entry>
2963 <entry>No event has occurred</entry>
2966 <entry>ZOOM_EVENT_CONNECT</entry>
2967 <entry>TCP/IP connect has initiated</entry>
2970 <entry>ZOOM_EVENT_SEND_DATA</entry>
2971 <entry>Data has been transmitted (sending)</entry>
2974 <entry>ZOOM_EVENT_RECV_DATA</entry>
2975 <entry>Data has been received)</entry>
2978 <entry>ZOOM_EVENT_TIMEOUT</entry>
2979 <entry>Timeout</entry>
2982 <entry>ZOOM_EVENT_UNKNOWN</entry>
2983 <entry>Unknown event</entry>
2986 <entry>ZOOM_EVENT_SEND_APDU</entry>
2987 <entry>An APDU has been transmitted (sending)</entry>
2990 <entry>ZOOM_EVENT_RECV_APDU</entry>
2991 <entry>An APDU has been received</entry>
2994 <entry>ZOOM_EVENT_RECV_RECORD</entry>
2995 <entry>A result-set record has been received</entry>
2998 <entry>ZOOM_EVENT_RECV_SEARCH</entry>
2999 <entry>A search result been received</entry>
3006 <chapter id="server">
3007 <title>Generic server</title>
3008 <sect1 id="server.introduction"><title>Introduction</title>
3010 If you aren't into documentation, a good way to learn how the
3011 back end interface works is to look at the <filename>backend.h</filename>
3012 file. Then, look at the small dummy-server in
3013 <filename>ztest/ztest.c</filename>. The <filename>backend.h</filename>
3014 file also makes a good reference, once you've chewed your way through
3015 the prose of this file.
3018 If you have a database system that you would like to make available by
3019 means of Z39.50 or SRU, &yaz; basically offers your two options. You
3020 can use the APIs provided by the &asn;, &odr;, and &comstack;
3022 create and decode PDUs, and exchange them with a client.
3023 Using this low-level interface gives you access to all fields and
3024 options of the protocol, and you can construct your server as close
3025 to your existing database as you like.
3026 It is also a fairly involved process, requiring
3027 you to set up an event-handling mechanism, protocol state machine,
3028 etc. To simplify server implementation, we have implemented a compact
3029 and simple, but reasonably full-functioned server-frontend that will
3030 handle most of the protocol mechanics, while leaving you to
3031 concentrate on your database interface.
3035 The backend interface was designed in anticipation of a specific
3036 integration task, while still attempting to achieve some degree of
3037 generality. We realize fully that there are points where the
3038 interface can be improved significantly. If you have specific
3039 functions or parameters that you think could be useful, send us a
3040 mail (or better, sign on to the mailing list referred to in the
3041 top-level README file). We will try to fit good suggestions into future
3042 releases, to the extent that it can be done without requiring
3043 too many structural changes in existing applications.
3048 The &yaz; server does not support XCQL.
3052 <sect1 id="server.frontend">
3053 <title>The Database Frontend</title>
3055 We refer to this software as a generic database frontend. Your
3056 database system is the <emphasis>backend database</emphasis>, and the
3057 interface between the two is called the <emphasis>backend API</emphasis>.
3058 The backend API consists of a small number of function handlers and
3059 structure definitions. You are required to provide the
3060 <function>main()</function> routine for the server (which can be
3061 quite simple), as well as a set of handlers to match each of the
3063 The interface functions that you write can use any mechanism you like
3064 to communicate with your database system: You might link the whole
3065 thing together with your database application and access it by
3066 function calls; you might use IPC to talk to a database server
3067 somewhere; or you might link with third-party software that handles
3068 the communication for you (like a commercial database client library).
3069 At any rate, the handlers will perform the tasks of:
3082 Scanning the database index (optional - if you wish to implement SCAN).
3085 Extended Services (optional).
3088 Result-Set Delete (optional).
3091 Result-Set Sort (optional).
3094 Return Explain for SRU (optional).
3098 (more functions will be added in time to support as much of
3099 Z39.50-1995 as possible).
3102 <sect1 id="server.backend">
3103 <title>The Backend API</title>
3105 The header file that you need to use the interface are in the
3106 <filename>include/yaz</filename> directory. It's called
3107 <filename>backend.h</filename>. It will include other files from
3108 the <filename>include/yaz</filename> directory, so you'll
3109 probably want to use the -I option of your compiler to tell it
3110 where to find the files. When you run
3111 <literal>make</literal> in the top-level &yaz; directory,
3112 everything you need to create your server is to link with the
3113 <filename>lib/libyaz.la</filename> library.
3116 <sect1 id="server.main">
3117 <title>Your main() Routine</title>
3119 As mentioned, your <function>main()</function> routine can be quite brief.
3120 If you want to initialize global parameters, or read global configuration
3121 tables, this is the place to do it. At the end of the routine, you should
3125 int statserv_main(int argc, char **argv,
3126 bend_initresult *(*bend_init)(bend_initrequest *r),
3127 void (*bend_close)(void *handle));
3130 The third and fourth arguments are pointers to handlers. Handler
3131 <function>bend_init</function> is called whenever the server receives
3132 an Initialize Request, so it serves as a Z39.50 session initializer. The
3133 <function>bend_close</function> handler is called when the session is
3137 <function>statserv_main</function> will establish listening sockets
3138 according to the parameters given. When connection requests are received,
3139 the event handler will typically <function>fork()</function> and
3140 create a sub-process to handle a new connection.
3141 Alternatively the server may be setup to create threads for each
3143 If you do use global variables and forking, you should be aware, then,
3144 that these cannot be shared between associations, unless you explicitly
3145 disable forking by command line parameters.
3148 The server provides a mechanism for controlling some of its behavior
3149 without using command-line options. The function
3152 statserv_options_block *statserv_getcontrol(void);
3155 will return a pointer to a <literal>struct statserv_options_block</literal>
3156 describing the current default settings of the server. The structure
3157 contains these elements:
3160 <term><literal>int dynamic</literal></term>
3162 A boolean value, which determines whether the server
3163 will fork on each incoming request (TRUE), or not (FALSE). Default is
3164 TRUE. This flag is only read by UNIX-based servers (WIN32 based servers
3169 <term><literal>int threads</literal></term>
3171 A boolean value, which determines whether the server
3172 will create a thread on each incoming request (TRUE), or not (FALSE).
3173 Default is FALSE. This flag is only read by UNIX-based servers
3174 that offer POSIX Threads support.
3175 WIN32-based servers always operate in threaded mode.
3179 <term><literal>int inetd</literal></term>
3181 A boolean value, which determines whether the server
3182 will operates under a UNIX INET daemon (inetd). Default is FALSE.
3186 <term><literal>char logfile[ODR_MAXNAME+1]</literal></term>
3187 <listitem><para>File for diagnostic output ("": stderr).
3191 <term><literal>char apdufile[ODR_MAXNAME+1]</literal></term>
3193 Name of file for logging incoming and outgoing APDUs
3194 ("": don't log APDUs, "-":
3195 <literal>stderr</literal>).
3199 <term><literal>char default_listen[1024]</literal></term>
3200 <listitem><para>Same form as the command-line specification of
3201 listener address. "": no default listener address.
3202 Default is to listen at "tcp:@:9999". You can only
3203 specify one default listener address in this fashion.
3207 <term><literal>enum oid_proto default_proto;</literal></term>
3208 <listitem><para>Either <literal>PROTO_Z3950</literal> or
3209 <literal>PROTO_SR</literal>.
3210 Default is <literal>PROTO_Z39_50</literal>.
3214 <term><literal>int idle_timeout;</literal></term>
3215 <listitem><para>Maximum session idle-time, in minutes. Zero indicates
3216 no (infinite) timeout. Default is 15 minutes.
3220 <term><literal>int maxrecordsize;</literal></term>
3221 <listitem><para>Maximum permissible record (message) size. Default
3222 is 64 MB. This amount of memory will only be allocated if a
3223 client requests a very large amount of records in one operation
3225 Set it to a lower number if you are worried about resource
3226 consumption on your host system.
3230 <term><literal>char configname[ODR_MAXNAME+1]</literal></term>
3231 <listitem><para>Passed to the backend when a new connection is received.
3235 <term><literal>char setuid[ODR_MAXNAME+1]</literal></term>
3236 <listitem><para>Set user id to the user specified, after binding
3237 the listener addresses.
3242 <literal>void (*bend_start)(struct statserv_options_block *p)</literal>
3244 <listitem><para>Pointer to function which is called after the
3245 command line options have been parsed - but before the server
3247 For forked UNIX servers this handler is called in the mother
3248 process; for threaded servers this handler is called in the
3250 The default value of this pointer is NULL in which case it
3251 isn't invoked by the frontend server.
3252 When the server operates as an NT service this handler is called
3253 whenever the service is started.
3258 <literal>void (*bend_stop)(struct statserv_options_block *p)</literal>
3260 <listitem><para>Pointer to function which is called whenever the server
3261 has stopped listening for incoming connections. This function pointer
3262 has a default value of NULL in which case it isn't called.
3263 When the server operates as an NT service this handler is called
3264 whenever the service is stopped.
3268 <term><literal>void *handle</literal></term>
3269 <listitem><para>User defined pointer (default value NULL).
3270 This is a per-server handle that can be used to specify "user-data".
3271 Do not confuse this with the session-handle as returned by bend_init.
3277 The pointer returned by <literal>statserv_getcontrol</literal> points to
3278 a static area. You are allowed to change the contents of the structure,
3279 but the changes will not take effect before you call
3282 void statserv_setcontrol(statserv_options_block *block);
3286 that you should generally update this structure before calling
3287 <function>statserv_main()</function>.
3291 <sect1 id="server.backendfunctions">
3292 <title>The Backend Functions</title>
3294 For each service of the protocol, the backend interface declares one or
3295 two functions. You are required to provide implementations of the
3296 functions representing the services that you wish to implement.
3298 <sect2 id="server.init">
3301 bend_initresult (*bend_init)(bend_initrequest *r);
3304 This handler is called once for each new connection request, after
3305 a new process/thread has been created, and an Initialize Request has
3306 been received from the client. The pointer to the
3307 <function>bend_init</function> handler is passed in the call to
3308 <function>statserv_start</function>.
3311 This handler is also called when operating in SRU mode - when
3312 a connection has been made (even though SRU does not offer
3316 Unlike previous versions of YAZ, the <function>bend_init</function> also
3317 serves as a handler that defines the Z39.50 services that the backend
3318 wish to support. Pointers to <emphasis>all</emphasis> service handlers,
3319 including search - and fetch must be specified here in this handler.
3322 The request - and result structures are defined as
3325 typedef struct bend_initrequest
3327 /** \brief user/name/password to be read */
3328 Z_IdAuthentication *auth;
3329 /** \brief encoding stream (for results) */
3331 /** \brief printing stream */
3333 /** \brief decoding stream (use stream for results) */
3335 /** \brief reference ID */
3336 Z_ReferenceId *referenceId;
3337 /** \brief peer address of client */
3340 /** \brief character set and language negotiation
3342 see include/yaz/z-charneg.h
3344 Z_CharSetandLanguageNegotiation *charneg_request;
3346 /** \brief character negotiation response */
3347 Z_External *charneg_response;
3349 /** \brief character set (encoding) for query terms
3351 This is NULL by default. It should be set to the native character
3352 set that the backend assumes for query terms */
3353 char *query_charset;
3355 /** \brief whehter query_charset also applies to recors
3357 Is 0 (No) by default. Set to 1 (yes) if records is in the same
3358 character set as queries. If in doubt, use 0 (No).
3360 int records_in_same_charset;
3362 char *implementation_id;
3363 char *implementation_name;
3364 char *implementation_version;
3366 /** \brief Z39.50 sort handler */
3367 int (*bend_sort)(void *handle, bend_sort_rr *rr);
3368 /** \brief SRU/Z39.50 search handler */
3369 int (*bend_search)(void *handle, bend_search_rr *rr);
3370 /** \brief SRU/Z39.50 fetch handler */
3371 int (*bend_fetch)(void *handle, bend_fetch_rr *rr);
3372 /** \brief SRU/Z39.50 present handler */
3373 int (*bend_present)(void *handle, bend_present_rr *rr);
3374 /** \brief Z39.50 extended services handler */
3375 int (*bend_esrequest) (void *handle, bend_esrequest_rr *rr);
3376 /** \brief Z39.50 delete result set handler */
3377 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3378 /** \brief Z39.50 scan handler */
3379 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3380 /** \brief Z39.50 segment facility handler */
3381 int (*bend_segment)(void *handle, bend_segment_rr *rr);
3382 /** \brief SRU explain handler */
3383 int (*bend_explain)(void *handle, bend_explain_rr *rr);
3384 /** \brief SRU scan handler */
3385 int (*bend_srw_scan)(void *handle, bend_scan_rr *rr);
3386 /** \brief SRU record update handler */
3387 int (*bend_srw_update)(void *handle, bend_update_rr *rr);
3389 /** \brief whether named result sets are supported (0=disable, 1=enable) */
3390 int named_result_sets;
3393 typedef struct bend_initresult
3395 int errcode; /* 0==OK */
3396 char *errstring; /* system error string or NULL */
3397 void *handle; /* private handle to the backend module */
3401 In general, the server frontend expects that the
3402 <literal>bend_*result</literal> pointer that you return is valid at
3403 least until the next call to a <literal>bend_* function</literal>.
3404 This applies to all of the functions described herein. The parameter
3405 structure passed to you in the call belongs to the server frontend, and
3406 you should not make assumptions about its contents after the current
3407 function call has completed. In other words, if you want to retain any
3408 of the contents of a request structure, you should copy them.
3411 The <literal>errcode</literal> should be zero if the initialization of
3412 the backend went well. Any other value will be interpreted as an error.
3413 The <literal>errstring</literal> isn't used in the current version, but
3414 one option would be to stick it in the initResponse as a VisibleString.
3415 The <literal>handle</literal> is the most important parameter. It should
3416 be set to some value that uniquely identifies the current session to
3417 the backend implementation. It is used by the frontend server in any
3418 future calls to a backend function.
3419 The typical use is to set it to point to a dynamically allocated state
3420 structure that is private to your backend module.
3423 The <literal>auth</literal> member holds the authentication information
3424 part of the Z39.50 Initialize Request. Interpret this if your serves
3425 requires authentication.
3428 The members <literal>peer_name</literal>,
3429 <literal>implementation_id</literal>,
3430 <literal>implementation_name</literal> and
3431 <literal>implementation_version</literal> holds
3432 DNS of client, ID of implementor, name
3433 of client (Z39.50) implementation - and version.
3436 The <literal>bend_</literal> - members are set to NULL when
3437 <function>bend_init</function> is called. Modify the pointers by
3438 setting them to point to backend functions.
3441 <sect2 id="server.search.retrieve">
3442 <title>Search and Retrieve</title>
3444 We now describe the handlers that are required to support search -
3445 and retrieve. You must support two functions - one for search - and one
3446 for fetch (retrieval of one record). If desirable you can provide a
3447 third handler which is called when a present request is received which
3448 allows you to optimize retrieval of multiple-records.
3451 int (*bend_search) (void *handle, bend_search_rr *rr);
3454 char *setname; /* name to give to this set */
3455 int replace_set; /* replace set, if it already exists */
3456 int num_bases; /* number of databases in list */
3457 char **basenames; /* databases to search */
3458 Z_ReferenceId *referenceId;/* reference ID */
3459 Z_Query *query; /* query structure */
3460 ODR stream; /* encode stream */
3461 ODR decode; /* decode stream */
3462 ODR print; /* print stream */
3464 bend_request request;
3465 bend_association association;
3467 int hits; /* number of hits */
3468 int errcode; /* 0==OK */
3469 char *errstring; /* system error string or NULL */
3470 Z_OtherInformation *search_info; /* additional search info */
3471 char *srw_sortKeys; /* holds SRU/SRW sortKeys info */
3472 char *srw_setname; /* holds SRU/SRW generated resultsetID */
3473 int *srw_setnameIdleTime; /* holds SRU/SRW life-time */
3474 int estimated_hit_count; /* if hit count is estimated */
3475 int partial_resultset; /* if result set is partial */
3479 The <function>bend_search</function> handler is a fairly close
3480 approximation of a protocol Z39.50 Search Request - and Response PDUs
3481 The <literal>setname</literal> is the resultSetName from the protocol.
3482 You are required to establish a mapping between the set name and whatever
3483 your backend database likes to use.
3484 Similarly, the <literal>replace_set</literal> is a boolean value
3485 corresponding to the resultSetIndicator field in the protocol.
3486 <literal>num_bases/basenames</literal> is a length of/array of character
3487 pointers to the database names provided by the client.
3488 The <literal>query</literal> is the full query structure as defined in
3489 the protocol ASN.1 specification.
3490 It can be either of the possible query types, and it's up to you to
3491 determine if you can handle the provided query type.
3492 Rather than reproduce the C interface here, we'll refer you to the
3493 structure definitions in the file
3494 <filename>include/yaz/z-core.h</filename>. If you want to look at the
3495 attributeSetId OID of the RPN query, you can either match it against
3496 your own internal tables, or you can use the <link linkend="tools.oid">
3500 The structure contains a number of hits, and an
3501 <literal>errcode/errstring</literal> pair. If an error occurs
3502 during the search, or if you're unhappy with the request, you should
3503 set the errcode to a value from the BIB-1 diagnostic set. The value
3504 will then be returned to the user in a nonsurrogate diagnostic record
3505 in the response. The <literal>errstring</literal>, if provided, will
3506 go in the addinfo field. Look at the protocol definition for the
3507 defined error codes, and the suggested uses of the addinfo field.
3510 The <function>bend_search</function> handler is also called when
3511 the frontend server receives a SRU SearchRetrieveRequest.
3512 For SRU, a CQL query is usually provided by the client.
3513 The CQL query is available as part of <literal>Z_Query</literal>
3514 structure (note that CQL is now part of Z39.50 via an external).
3515 To support CQL in existing implementations that only do Type-1,
3516 we refer to the CQL-to-PQF tool described
3517 <link linkend="cql.to.pqf">here</link>.
3520 To maintain backwards compatibility, the frontend server
3521 of yaz always assume that error codes are BIB-1 diagnostics.
3522 For SRU operation, a Bib-1 diagnostic code is mapped to
3526 int (*bend_fetch) (void *handle, bend_fetch_rr *rr);
3528 typedef struct bend_fetch_rr {
3529 char *setname; /* set name */
3530 int number; /* record number */
3531 Z_ReferenceId *referenceId;/* reference ID */
3532 Odr_oid *request_format; /* format, transfer syntax (OID) */
3533 Z_RecordComposition *comp; /* Formatting instructions */
3534 ODR stream; /* encoding stream - memory source if req */
3535 ODR print; /* printing stream */
3537 char *basename; /* name of database that provided record */
3538 int len; /* length of record or -1 if structured */
3539 char *record; /* record */
3540 int last_in_set; /* is it? */
3541 Odr_oid *output_format; /* response format/syntax (OID) */
3542 int errcode; /* 0==success */
3543 char *errstring; /* system error string or NULL */
3544 int surrogate_flag; /* surrogate diagnostic */
3545 char *schema; /* string record schema input/output */
3549 The frontend server calls the <function>bend_fetch</function> handler
3550 when it needs database records to fulfill a Z39.50 Search Request, a
3551 Z39.50 Present Request or a SRU SearchRetrieveRequest.
3552 The <literal>setname</literal> is simply the name of the result set
3553 that holds the reference to the desired record.
3554 The <literal>number</literal> is the offset into the set (with 1
3555 being the first record in the set). The <literal>format</literal> field
3556 is the record format requested by the client (See
3557 <xref linkend="tools.oid"/>).
3558 A value of NULL for <literal>format</literal> indicates that the
3559 client did not request a specific format.
3560 The <literal>stream</literal> argument is an &odr; stream which
3561 should be used for allocating space for structured data records.
3562 The stream will be reset when all records have been assembled, and
3563 the response package has been transmitted.
3564 For unstructured data, the backend is responsible for maintaining a
3565 static or dynamic buffer for the record between calls.
3568 If a SRU SearchRetrieveRequest is received by the frontend server,
3569 the <literal>referenceId</literal> is NULL and the
3570 <literal>format</literal> (transfer syntax) is the OID for XML.
3571 The schema for SRU is stored in both the
3572 <literal>Z_RecordComposition</literal>
3573 structure and <literal>schema</literal> (simple string).
3576 In the structure, the <literal>basename</literal> is the name of the
3577 database that holds the
3578 record. <literal>len</literal> is the length of the record returned, in
3579 bytes, and <literal>record</literal> is a pointer to the record.
3580 <literal>last_in_set</literal> should be nonzero only if the record
3581 returned is the last one in the given result set.
3582 <literal>errcode</literal> and <literal>errstring</literal>, if
3583 given, will be interpreted as a global error pertaining to the
3584 set, and will be returned in a non-surrogate-diagnostic.
3585 If you wish to return the error as a surrogate-diagnostic
3586 (local error) you can do this by setting
3587 <literal>surrogate_flag</literal> to 1 also.
3590 If the <literal>len</literal> field has the value -1, then
3591 <literal>record</literal> is assumed to point to a constructed data
3592 type. The <literal>format</literal> field will be used to determine
3593 which encoder should be used to serialize the data.
3597 If your backend generates structured records, it should use
3598 <function>odr_malloc()</function> on the provided stream for allocating
3599 data: This allows the frontend server to keep track of the record sizes.
3603 The <literal>format</literal> field is mapped to an object identifier
3604 in the direct reference of the resulting EXTERNAL representation
3609 The current version of &yaz; only supports the direct reference mode.
3613 int (*bend_present) (void *handle, bend_present_rr *rr);
3616 char *setname; /* set name */
3618 int number; /* record number */
3619 Odr_oid *format; /* format, transfer syntax (OID) */
3620 Z_ReferenceId *referenceId;/* reference ID */
3621 Z_RecordComposition *comp; /* Formatting instructions */
3622 ODR stream; /* encoding stream - memory source if required */
3623 ODR print; /* printing stream */
3624 bend_request request;
3625 bend_association association;
3627 int hits; /* number of hits */
3628 int errcode; /* 0==OK */
3629 char *errstring; /* system error string or NULL */
3633 The <function>bend_present</function> handler is called when
3634 the server receives a Z39.50 Present Request.
3635 The <literal>setname</literal>,
3636 <literal>start</literal> and <literal>number</literal> is the
3637 name of the result set - start position - and number of records to
3638 be retrieved respectively. <literal>format</literal> and
3639 <literal>comp</literal> is the preferred transfer syntax and element
3640 specifications of the present request.
3643 Note that this is handler serves as a supplement for
3644 <function>bend_fetch</function> and need not to be defined in order to
3645 support search - and retrieve.
3648 <sect2 id="server.delete">
3649 <title>Delete</title>
3651 For back-ends that supports delete of a result set only one handler
3655 int (*bend_delete)(void *handle, bend_delete_rr *rr);
3657 typedef struct bend_delete_rr {
3661 Z_ReferenceId *referenceId;
3662 int delete_status; /* status for the whole operation */
3663 int *statuses; /* status each set - indexed as setnames */
3670 The delete set function definition is rather primitive, mostly because
3671 we have had no practical need for it as of yet. If someone wants
3672 to provide a full delete service, we'd be happy to add the
3673 extra parameters that are required. Are there clients out there
3674 that will actually delete sets they no longer need?
3678 <sect2 id="server.scan">
3681 For servers that wish to offer the scan service one handler
3685 int (*bend_scan)(void *handle, bend_scan_rr *rr);
3688 BEND_SCAN_SUCCESS, /* ok */
3689 BEND_SCAN_PARTIAL /* not all entries could be found */
3692 typedef struct bend_scan_rr {
3693 int num_bases; /* number of elements in databaselist */
3694 char **basenames; /* databases to search */
3695 Odr_oid *attributeset;
3696 Z_ReferenceId *referenceId; /* reference ID */
3697 Z_AttributesPlusTerm *term;
3698 ODR stream; /* encoding stream - memory source if required */
3699 ODR print; /* printing stream */
3701 int *step_size; /* step size */
3702 int term_position; /* desired index of term in result list/returned */
3703 int num_entries; /* number of entries requested/returned */
3705 /* scan term entries. The called handler does not have
3706 to allocate this. Size of entries is num_entries (see above) */
3707 struct scan_entry *entries;
3708 bend_scan_status status;
3711 char *scanClause; /* CQL scan clause */
3712 char *setname; /* Scan in result set (NULL if omitted) */
3716 This backend server handles both Z39.50 scan
3717 and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
3718 Z39.50 Scan , it must check for a non-NULL value of
3719 <literal>scanClause</literal>.
3723 if designed today, it would be a choice using a union or similar,
3724 but that would break binary compatibility with existing servers.
3729 <sect1 id="server.invocation">
3730 <title>Application Invocation</title>
3732 The finished application has the following
3733 invocation syntax (by way of <function>statserv_main()</function>):
3741 A listener specification consists of a transport mode followed by a
3742 colon (:) followed by a listener address. The transport mode is
3743 either <literal>tcp</literal>, <literal>unix:</literal> or
3744 <literal>ssl</literal>.
3747 For TCP and SSL, an address has the form
3750 hostname | IP-number [: portnumber]
3753 The port number defaults to 210 (standard Z39.50 port).
3756 For UNIX, the address is the filename of socket.
3759 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
3760 maps to <literal>IN6ADDR_ANY_INIT</literal> with
3761 IPV4 binding as well (bindv6only=0),
3762 The special hostname <literal>@4</literal> binds to
3763 <literal>INADDR_ANY</literal> (IPV4 only listener).
3764 The special hostname <literal>@6</literal> binds to
3765 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
3767 <example id="server.example.running.unix">
3768 <title>Running the GFS on Unix</title>
3770 Assuming the server application <replaceable>appname</replaceable> is
3771 started as root, the following will make it listen on port 210.
3772 The server will change identity to <literal>nobody</literal>
3773 and write its log to <filename>/var/log/app.log</filename>.
3775 application -l /var/log/app.log -u nobody tcp:@:210
3779 The server will accept Z39.50 requests and offer SRU service on port 210.
3782 <example id="server.example.apache.sru">
3783 <title>Setting up Apache as SRU Frontend</title>
3785 If you use <ulink url="&url.apache;">Apache</ulink>
3786 as your public web server and want to offer HTTP port 80
3787 access to the YAZ server on 210, you can use the
3788 <ulink url="&url.apache.directive.proxypass;">
3789 <literal>ProxyPass</literal></ulink>
3791 If you have virtual host
3792 <literal>srw.mydomain</literal> you can use the following directives
3793 in Apache's httpd.conf:
3796 ErrorLog /home/srw/logs/error_log
3797 TransferLog /home/srw/logs/access_log
3798 ProxyPass / http://srw.mydomain:210/
3803 The above for the Apache 1.3 series.
3806 <example id="server.example.local.access">
3807 <title>Running a server with local access only</title>
3809 Servers that is only being accessed from the local host should listen
3810 on UNIX file socket rather than a Internet socket. To listen on
3811 <filename>/tmp/mysocket</filename> start the server as follows:
3813 application unix:/tmp/mysocket
3818 <sect1 id="server.vhosts">
3819 <title>GFS Configuration and Virtual Hosts</title>
3824 <title>The Z39.50 ASN.1 Module</title>
3825 <sect1 id="asn.introduction">
3826 <title>Introduction</title>
3828 The &asn; module provides you with a set of C struct definitions for the
3829 various PDUs of the Z39.50 protocol, as well as for the complex types
3830 appearing within the PDUs. For the primitive data types, the C
3831 representation often takes the form of an ordinary C language type,
3832 such as <literal>Odr_int</literal> which is equivalent to an integral
3833 C integer. For ASN.1 constructs that have no direct
3834 representation in C, such as general octet strings and bit strings,
3835 the &odr; module (see section <link linkend="odr">The ODR Module</link>)
3836 provides auxiliary definitions.
3839 The &asn; module is located in sub directory <filename>z39.50</filename>.
3840 There you'll find C files that implements encoders and decoders for the
3841 Z39.50 types. You'll also find the protocol definitions:
3842 <filename>z3950v3.asn</filename>, <filename>esupdate.asn</filename>,
3846 <sect1 id="asn.preparing">
3847 <title>Preparing PDUs</title>
3849 A structure representing a complex ASN.1 type doesn't in itself contain the
3850 members of that type. Instead, the structure contains
3851 <emphasis>pointers</emphasis> to the members of the type.
3852 This is necessary, in part, to allow a mechanism for specifying which
3853 of the optional structure (SEQUENCE) members are present, and which
3854 are not. It follows that you will need to somehow provide space for
3855 the individual members of the structure, and set the pointers to
3856 refer to the members.
3859 The conversion routines don't care how you allocate and maintain your
3860 C structures - they just follow the pointers that you provide.
3861 Depending on the complexity of your application, and your personal
3862 taste, there are at least three different approaches that you may take
3863 when you allocate the structures.
3866 You can use static or automatic local variables in the function that
3867 prepares the PDU. This is a simple approach, and it provides the most
3868 efficient form of memory management. While it works well for flat
3869 PDUs like the InitReqest, it will generally not be sufficient for say,
3870 the generation of an arbitrarily complex RPN query structure.
3873 You can individually create the structure and its members using the
3874 <function>malloc(2)</function> function. If you want to ensure that
3875 the data is freed when it is no longer needed, you will have to
3876 define a function that individually releases each member of a
3877 structure before freeing the structure itself.
3880 You can use the <function>odr_malloc()</function> function (see
3881 <xref linkend="odr.use"/> for details). When you use
3882 <function>odr_malloc()</function>, you can release all of the
3883 allocated data in a single operation, independent of any pointers and
3884 relations between the data. <function>odr_malloc()</function> is based on a
3885 "nibble-memory"
3886 scheme, in which large portions of memory are allocated, and then
3887 gradually handed out with each call to <function>odr_malloc()</function>.
3888 The next time you call <function>odr_reset()</function>, all of the
3889 memory allocated since the last call is recycled for future use (actually,
3890 it is placed on a free-list).
3893 You can combine all of the methods described here. This will often be
3894 the most practical approach. For instance, you might use
3895 <function>odr_malloc()</function> to allocate an entire structure and
3896 some of its elements, while you leave other elements pointing to global
3897 or per-session default variables.
3900 The &asn; module provides an important aid in creating new PDUs. For
3901 each of the PDU types (say, <function>Z_InitRequest</function>), a
3902 function is provided that allocates and initializes an instance of
3903 that PDU type for you. In the case of the InitRequest, the function is
3904 simply named <function>zget_InitRequest()</function>, and it sets up
3905 reasonable default value for all of the mandatory members. The optional
3906 members are generally initialized to null pointers. This last aspect
3907 is very important: it ensures that if the PDU definitions are
3908 extended after you finish your implementation (to accommodate
3909 new versions of the protocol, say), you won't get into trouble with
3910 uninitialized pointers in your structures. The functions use
3911 <function>odr_malloc()</function> to
3912 allocate the PDUs and its members, so you can free everything again with a
3913 single call to <function>odr_reset()</function>. We strongly recommend
3914 that you use the <literal>zget_*</literal>
3915 functions whenever you are preparing a PDU (in a C++ API, the
3916 <literal>zget_</literal>
3917 functions would probably be promoted to constructors for the
3921 The prototype for the individual PDU types generally look like this:
3924 Z_<type> *zget_<type>(ODR o);
3930 Z_InitRequest *zget_InitRequest(ODR o);
3933 The &odr; handle should generally be your encoding stream, but it
3937 As well as the individual PDU functions, a function
3938 <function>zget_APDU()</function> is provided, which allocates
3939 a top-level Z-APDU of the type requested:
3942 Z_APDU *zget_APDU(ODR o, int which);
3945 The <varname>which</varname> parameter is (of course) the discriminator
3946 belonging to the <varname>Z_APDU</varname> <literal>CHOICE</literal> type.
3947 All of the interface described here is provided by the &asn; module, and
3948 you access it through the <filename>proto.h</filename> header file.
3951 <sect1 id="asn.external">
3952 <title>EXTERNAL Data</title>
3954 In order to achieve extensibility and adaptability to different
3955 application domains, the new version of the protocol defines many
3956 structures outside of the main ASN.1 specification, referencing them
3957 through ASN.1 EXTERNAL constructs. To simplify the construction and
3958 access to the externally referenced data, the &asn; module defines a
3959 specialized version of the EXTERNAL construct, called
3960 <literal>Z_External</literal>.It is defined thus:
3963 typedef struct Z_External
3965 Odr_oid *direct_reference;
3966 int *indirect_reference;
3971 Z_External_single = 0,
3973 Z_External_arbitrary,
3975 /* Specific types */
3977 Z_External_explainRecord,
3978 Z_External_resourceReport1,
3979 Z_External_resourceReport2
3987 Odr_any *single_ASN1_type;
3988 Odr_oct *octet_aligned;
3989 Odr_bitmask *arbitrary;
3991 /* Specific types */
3993 Z_ExplainRecord *explainRecord;
3994 Z_ResourceReport1 *resourceReport1;
3995 Z_ResourceReport2 *resourceReport2;
4003 When decoding, the &asn; module will attempt to determine which
4004 syntax describes the data by looking at the reference fields
4005 (currently only the direct-reference). For ASN.1 structured data, you
4006 need only consult the <literal>which</literal> field to determine the
4007 type of data. You can the access the data directly through the union.
4008 When constructing data for encoding, you set the union pointer to point
4009 to the data, and set the <literal>which</literal> field accordingly.
4010 Remember also to set the direct (or indirect) reference to the correct
4011 OID for the data type.
4012 For non-ASN.1 data such as MARC records, use the
4013 <literal>octet_aligned</literal> arm of the union.
4016 Some servers return ASN.1 structured data values (eg. database
4017 records) as BER-encoded records placed in the
4018 <literal>octet-aligned</literal> branch of the EXTERNAL CHOICE.
4019 The ASN-module will <emphasis>not</emphasis> automatically decode
4020 these records. To help you decode the records in the application, the
4024 Z_ext_typeent *z_ext_gettypebyref(const oid *oid);
4027 Can be used to retrieve information about the known, external data
4028 types. The function return a pointer to a static area, or NULL, if no
4029 match for the given direct reference is found. The
4030 <literal>Z_ext_typeent</literal>
4034 typedef struct Z_ext_typeent
4036 int oid[OID_SIZE]; /* the direct-reference OID. */
4037 int what; /* discriminator value for the external CHOICE */
4038 Odr_fun fun; /* decoder function */
4042 The <literal>what</literal> member contains the
4043 <literal>Z_External</literal> union discriminator value for the
4044 given type: For the SUTRS record syntax, the value would be
4045 <literal>Z_External_sutrs</literal>.
4046 The <literal>fun</literal> member contains a pointer to the
4047 function which encodes/decodes the given type. Again, for the SUTRS
4048 record syntax, the value of <literal>fun</literal> would be
4049 <literal>z_SUTRS</literal> (a function pointer).
4052 If you receive an EXTERNAL which contains an octet-string value that
4053 you suspect of being an ASN.1-structured data value, you can use
4054 <literal>z_ext_gettypebyref</literal> to look for the provided
4056 If the return value is different from NULL, you can use the provided
4057 function to decode the BER string (see <xref linkend="odr.use"/>
4061 If you want to <emphasis>send</emphasis> EXTERNALs containing
4062 ASN.1-structured values in the occtet-aligned branch of the CHOICE, this
4063 is possible too. However, on the encoding phase, it requires a somewhat
4064 involved juggling around of the various buffers involved.
4067 If you need to add new, externally defined data types, you must update
4068 the struct above, in the source file <filename>prt-ext.h</filename>, as
4069 well as the encoder/decoder in the file <filename>prt-ext.c</filename>.
4070 When changing the latter, remember to update both the
4071 <literal>arm</literal> arrary and the list
4072 <literal>type_table</literal>, which drives the CHOICE biasing that
4073 is necessary to tell the different, structured types apart
4078 Eventually, the EXTERNAL processing will most likely
4079 automatically insert the correct OIDs or indirect-refs. First,
4080 however, we need to determine how application-context management
4081 (specifically the presentation-context-list) should fit into the
4086 <sect1 id="asn.pdu">
4087 <title>PDU Contents Table</title>
4089 We include, for reference, a listing of the fields of each top-level
4090 PDU, as well as their default settings.
4092 <table frame="top" id="asn.default.initialize.request">
4093 <title>Default settings for PDU Initialize Request</title>
4095 <colspec colwidth="7*" colname="field"></colspec>
4096 <colspec colwidth="5*" colname="type"></colspec>
4097 <colspec colwidth="7*" colname="value"></colspec>
4100 <entry>Field</entry>
4102 <entry>Default Value</entry>
4107 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4110 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4113 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4116 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4119 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4122 idAuthentication</entry><entry>Z_IdAuthentication</entry><entry>NULL
4125 implementationId</entry><entry>char*</entry><entry>"81"
4128 implementationName</entry><entry>char*</entry><entry>"YAZ"
4131 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4134 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4137 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4142 <table frame="top" id="asn.default.initialize.response">
4143 <title>Default settings for PDU Initialize Response</title>
4145 <colspec colwidth="7*" colname="field"></colspec>
4146 <colspec colwidth="5*" colname="type"></colspec>
4147 <colspec colwidth="7*" colname="value"></colspec>
4150 <entry>Field</entry>
4152 <entry>Default Value</entry>
4157 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4160 protocolVersion</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4163 options</entry><entry>Odr_bitmask</entry><entry>Empty bitmask
4166 preferredMessageSize</entry><entry>Odr_int</entry><entry>30*1024
4169 maximumRecordSize</entry><entry>Odr_int</entry><entry>30*1024
4172 result</entry><entry>Odr_bool</entry><entry>TRUE
4175 implementationId</entry><entry>char*</entry><entry>"id)"
4178 implementationName</entry><entry>char*</entry><entry>"YAZ"
4181 implementationVersion</entry><entry>char*</entry><entry>YAZ_VERSION
4184 userInformationField</entry><entry>Z_UserInformation</entry><entry>NULL
4187 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4192 <table frame="top" id="asn.default.search.request">
4193 <title>Default settings for PDU Search Request</title>
4195 <colspec colwidth="7*" colname="field"></colspec>
4196 <colspec colwidth="5*" colname="type"></colspec>
4197 <colspec colwidth="7*" colname="value"></colspec>
4200 <entry>Field</entry>
4202 <entry>Default Value</entry>
4207 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4210 smallSetUpperBound</entry><entry>Odr_int</entry><entry>0
4213 largeSetLowerBound</entry><entry>Odr_int</entry><entry>1
4216 mediumSetPresentNumber</entry><entry>Odr_int</entry><entry>0
4219 replaceIndicator</entry><entry>Odr_bool</entry><entry>TRUE
4222 resultSetName</entry><entry>char *</entry><entry>"default"
4225 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4228 databaseNames</entry><entry>char **</entry><entry>NULL
4231 smallSetElementSetNames</entry><entry>Z_ElementSetNames
4235 mediumSetElementSetNames</entry><entry>Z_ElementSetNames
4239 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4242 query</entry><entry>Z_Query</entry><entry>NULL
4245 additionalSearchInfo</entry><entry>Z_OtherInformation
4249 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4254 <table frame="top" id="asn.default.search.response">
4255 <title>Default settings for PDU Search Response</title>
4257 <colspec colwidth="7*" colname="field"></colspec>
4258 <colspec colwidth="5*" colname="type"></colspec>
4259 <colspec colwidth="7*" colname="value"></colspec>
4262 <entry>Field</entry>
4264 <entry>Default Value</entry>
4269 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4272 resultCount</entry><entry>Odr_int</entry><entry>0
4275 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4278 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4281 searchStatus</entry><entry>Odr_bool</entry><entry>TRUE
4284 resultSetStatus</entry><entry>Odr_int</entry><entry>NULL
4287 presentStatus</entry><entry>Odr_int</entry><entry>NULL
4290 records</entry><entry>Z_Records</entry><entry>NULL
4293 additionalSearchInfo</entry>
4294 <entry>Z_OtherInformation</entry><entry>NULL
4297 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4302 <table frame="top" id="asn.default.present.request">
4303 <title>Default settings for PDU Present Request</title>
4305 <colspec colwidth="7*" colname="field"></colspec>
4306 <colspec colwidth="5*" colname="type"></colspec>
4307 <colspec colwidth="7*" colname="value"></colspec>
4310 <entry>Field</entry>
4312 <entry>Default Value</entry>
4317 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4320 resultSetId</entry><entry>char*</entry><entry>"default"
4323 resultSetStartPoint</entry><entry>Odr_int</entry><entry>1
4326 numberOfRecordsRequested</entry><entry>Odr_int</entry><entry>10
4329 num_ranges</entry><entry>Odr_int</entry><entry>0
4332 additionalRanges</entry><entry>Z_Range</entry><entry>NULL
4335 recordComposition</entry><entry>Z_RecordComposition</entry><entry>NULL
4338 preferredRecordSyntax</entry><entry>Odr_oid</entry><entry>NULL
4341 maxSegmentCount</entry><entry>Odr_int</entry><entry>NULL
4344 maxRecordSize</entry><entry>Odr_int</entry><entry>NULL
4347 maxSegmentSize</entry><entry>Odr_int</entry><entry>NULL
4350 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4355 <table frame="top" id="asn.default.present.response">
4356 <title>Default settings for PDU Present Response</title>
4358 <colspec colwidth="7*" colname="field"></colspec>
4359 <colspec colwidth="5*" colname="type"></colspec>
4360 <colspec colwidth="7*" colname="value"></colspec>
4363 <entry>Field</entry>
4365 <entry>Default Value</entry>
4370 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4373 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>0
4376 nextResultSetPosition</entry><entry>Odr_int</entry><entry>0
4379 presentStatus</entry><entry>Odr_int</entry><entry>Z_PresentStatus_success
4382 records</entry><entry>Z_Records</entry><entry>NULL
4385 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4390 <table frame="top" id="asn.default.delete.result.set.request">
4391 <title>Default settings for Delete Result Set Request</title>
4393 <colspec colwidth="7*" colname="field"></colspec>
4394 <colspec colwidth="5*" colname="type"></colspec>
4395 <colspec colwidth="7*" colname="value"></colspec>
4398 <entry>Field</entry>
4400 <entry>Default Value</entry>
4404 <row><entry>referenceId
4405 </entry><entry>Z_ReferenceId</entry><entry>NULL
4408 deleteFunction</entry><entry>Odr_int</entry><entry>Z_DeleteResultSetRequest_list
4411 num_ids</entry><entry>Odr_int</entry><entry>0
4414 resultSetList</entry><entry>char**</entry><entry>NULL
4417 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4422 <table frame="top" id="asn.default.delete.result.set.response">
4423 <title>Default settings for Delete Result Set Response</title>
4425 <colspec colwidth="7*" colname="field"></colspec>
4426 <colspec colwidth="5*" colname="type"></colspec>
4427 <colspec colwidth="7*" colname="value"></colspec>
4430 <entry>Field</entry>
4432 <entry>Default Value</entry>
4437 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4440 deleteOperationStatus</entry><entry>Odr_int</entry>
4441 <entry>Z_DeleteStatus_success</entry></row>
4443 num_statuses</entry><entry>Odr_int</entry><entry>0
4446 deleteListStatuses</entry><entry>Z_ListStatus**</entry><entry>NULL
4449 numberNotDeleted</entry><entry>Odr_int</entry><entry>NULL
4452 num_bulkStatuses</entry><entry>Odr_int</entry><entry>0
4455 bulkStatuses</entry><entry>Z_ListStatus</entry><entry>NUL
4458 deleteMessage</entry><entry>char*</entry><entry>NULL
4461 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4466 <table frame="top" id="asn.default.scan.request">
4467 <title>Default settings for Scan Request</title>
4469 <colspec colwidth="7*" colname="field"></colspec>
4470 <colspec colwidth="5*" colname="type"></colspec>
4471 <colspec colwidth="7*" colname="value"></colspec>
4474 <entry>Field</entry>
4476 <entry>Default Value</entry>
4481 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4484 num_databaseNames</entry><entry>Odr_int</entry><entry>0
4487 databaseNames</entry><entry>char**</entry><entry>NULL
4490 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4493 termListAndStartPoint</entry><entry>Z_AttributesPlus...
4494 </entry><entry>NULL</entry></row>
4496 stepSize</entry><entry>Odr_int</entry><entry>NULL
4499 numberOfTermsRequested</entry><entry>Odr_int</entry><entry>20
4502 preferredPositionInResponse</entry><entry>Odr_int</entry><entry>NULL
4505 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4510 <table frame="top" id="asn.default.scan.response">
4511 <title>Default settings for Scan Response</title>
4513 <colspec colwidth="7*" colname="field"></colspec>
4514 <colspec colwidth="5*" colname="type"></colspec>
4515 <colspec colwidth="7*" colname="value"></colspec>
4518 <entry>Field</entry>
4520 <entry>Default Value</entry>
4525 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4528 stepSize</entry><entry>Odr_int</entry><entry>NULL
4531 scanStatus</entry><entry>Odr_int</entry><entry>Z_Scan_success
4534 numberOfEntriesReturned</entry><entry>Odr_int</entry><entry>0
4537 positionOfTerm</entry><entry>Odr_int</entry><entry>NULL
4540 entries</entry><entry>Z_ListEntris</entry><entry>NULL
4543 attributeSet</entry><entry>Odr_oid</entry><entry>NULL
4546 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4551 <table frame="top" id="asn.default.trigger.resource.control.request">
4552 <title>Default settings for Trigger Resource Control Request</title>
4554 <colspec colwidth="7*" colname="field"></colspec>
4555 <colspec colwidth="5*" colname="type"></colspec>
4556 <colspec colwidth="7*" colname="value"></colspec>
4559 <entry>Field</entry>
4561 <entry>Default Value</entry>
4566 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4569 requestedAction</entry><entry>Odr_int</entry><entry>
4570 Z_TriggerResourceCtrl_resou..
4573 prefResourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4576 resultSetWanted</entry><entry>Odr_bool</entry><entry>NULL
4579 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4584 <table frame="top" id="asn.default.resource.control.request">
4585 <title>Default settings for Resource Control Request</title>
4587 <colspec colwidth="7*" colname="field"></colspec>
4588 <colspec colwidth="5*" colname="type"></colspec>
4589 <colspec colwidth="7*" colname="value"></colspec>
4592 <entry>Field</entry>
4594 <entry>Default Value</entry>
4599 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4602 suspendedFlag</entry><entry>Odr_bool</entry><entry>NULL
4605 resourceReport</entry><entry>Z_External</entry><entry>NULL
4608 partialResultsAvailable</entry><entry>Odr_int</entry><entry>NULL
4611 responseRequired</entry><entry>Odr_bool</entry><entry>FALSE
4614 triggeredRequestFlag</entry><entry>Odr_bool</entry><entry>NULL
4617 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4622 <table frame="top" id="asn.default.resource.control.response">
4623 <title>Default settings for Resource Control Response</title>
4625 <colspec colwidth="7*" colname="field"></colspec>
4626 <colspec colwidth="5*" colname="type"></colspec>
4627 <colspec colwidth="7*" colname="value"></colspec>
4630 <entry>Field</entry>
4632 <entry>Default Value</entry>
4637 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4640 continueFlag</entry><entry>bool_t</entry><entry>TRUE
4643 resultSetWanted</entry><entry>bool_t</entry><entry>NULL
4646 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4651 <table frame="top" id="asn.default.access.control.request">
4652 <title>Default settings for Access Control Request</title>
4654 <colspec colwidth="7*" colname="field"></colspec>
4655 <colspec colwidth="5*" colname="type"></colspec>
4656 <colspec colwidth="7*" colname="value"></colspec>
4659 <entry>Field</entry>
4661 <entry>Default Value</entry>
4666 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4669 which</entry><entry>enum</entry><entry>Z_AccessRequest_simpleForm;
4672 u</entry><entry>union</entry><entry>NULL
4675 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4680 <table frame="top" id="asn.default.access.control.response">
4681 <title>Default settings for Access Control Response</title>
4683 <colspec colwidth="7*" colname="field"></colspec>
4684 <colspec colwidth="5*" colname="type"></colspec>
4685 <colspec colwidth="7*" colname="value"></colspec>
4688 <entry>Field</entry>
4690 <entry>Default Value</entry>
4695 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4698 which</entry><entry>enum</entry><entry>Z_AccessResponse_simpleForm
4701 u</entry><entry>union</entry><entry>NULL
4704 diagnostic</entry><entry>Z_DiagRec</entry><entry>NULL
4707 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4712 <table frame="top" id="asn.default.segment">
4713 <title>Default settings for Segment</title>
4715 <colspec colwidth="7*" colname="field"></colspec>
4716 <colspec colwidth="5*" colname="type"></colspec>
4717 <colspec colwidth="7*" colname="value"></colspec>
4720 <entry>Field</entry>
4722 <entry>Default Value</entry>
4727 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4730 numberOfRecordsReturned</entry><entry>Odr_int</entry><entry>value=0
4733 num_segmentRecords</entry><entry>Odr_int</entry><entry>0
4736 segmentRecords</entry><entry>Z_NamePlusRecord</entry><entry>NULL
4738 <row><entry>otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4743 <table frame="top" id="asn.default.close">
4744 <title>Default settings for Close</title>
4746 <colspec colwidth="7*" colname="field"></colspec>
4747 <colspec colwidth="5*" colname="type"></colspec>
4748 <colspec colwidth="7*" colname="value"></colspec>
4751 <entry>Field</entry>
4753 <entry>Default Value</entry>
4758 referenceId</entry><entry>Z_ReferenceId</entry><entry>NULL
4761 closeReason</entry><entry>Odr_int</entry><entry>Z_Close_finished
4764 diagnosticInformation</entry><entry>char*</entry><entry>NULL
4767 resourceReportFormat</entry><entry>Odr_oid</entry><entry>NULL
4770 resourceFormat</entry><entry>Z_External</entry><entry>NULL
4773 otherInfo</entry><entry>Z_OtherInformation</entry><entry>NULL
4781 <title>SOAP and SRU</title>
4782 <sect1 id="soap.introduction">
4783 <title>Introduction</title>
4785 &yaz; uses a very simple implementation of
4786 <ulink url="&url.soap;">SOAP</ulink> that only,
4787 currenly, supports what is sufficient to offer SRU SOAP functionality.
4788 The implementation uses the
4789 <ulink url="&url.libxml2.api.tree;">tree API</ulink> of
4790 libxml2 to encode and decode SOAP packages.
4793 Like the Z39.50 ASN.1 module, the &yaz; SRU implementation uses
4794 simple C structs to represent SOAP packages as well as
4798 <sect1 id="soap.http">
4801 &yaz; only offers HTTP as transport carrier for SOAP, but it is
4802 relatively easy to change that.
4805 The following definition of <literal>Z_GDU</literal> (Generic Data
4806 Unit) allows for both HTTP and Z39.50 in one packet.
4809 #include <yaz/zgdu.h>
4811 #define Z_GDU_Z3950 1
4812 #define Z_GDU_HTTP_Request 2
4813 #define Z_GDU_HTTP_Response 3
4818 Z_HTTP_Request *HTTP_Request;
4819 Z_HTTP_Response *HTTP_Response;
4824 The corresponding Z_GDU encoder/decoder is <function>z_GDU</function>.
4825 The <literal>z3950</literal> is any of the known BER encoded Z39.50
4827 <literal>HTTP_Request</literal> and <literal>HTTP_Response</literal>
4828 is the HTTP Request and Response respectively.
4831 <sect1 id="soap.xml">
4832 <title>SOAP Packages</title>
4834 Every SOAP package in &yaz; is represented as follows:
4836 #include <yaz/soap.h>
4850 #define Z_SOAP_fault 1
4851 #define Z_SOAP_generic 2
4852 #define Z_SOAP_error 3
4856 Z_SOAP_Fault *fault;
4857 Z_SOAP_Generic *generic;
4858 Z_SOAP_Fault *soap_error;
4865 The <literal>fault</literal> and <literal>soap_error</literal>
4866 arms represent both a SOAP fault - struct
4867 <literal>Z_SOAP_Fault</literal>. Any other generic
4868 (valid) package is represented by <literal>Z_SOAP_Generic</literal>.
4871 The <literal>ns</literal> as part of <literal>Z_SOAP</literal>
4872 is the namespace for SOAP itself and reflects the SOAP
4873 version. For version 1.1 it is
4874 <literal>http://schemas.xmlsoap.org/soap/envelope/</literal>,
4875 for version 1.2 it is
4876 <literal>http://www.w3.org/2001/06/soap-envelope</literal>.
4879 int z_soap_codec(ODR o, Z_SOAP **pp,
4880 char **content_buf, int *content_len,
4881 Z_SOAP_Handler *handlers);
4884 The <literal>content_buf</literal> and <literal>content_len</literal>
4885 is XML buffer and length of buffer respectively.
4888 The <literal>handlers</literal> is a list of SOAP codec
4889 handlers - one handler for each service namespace. For SRU SOAP, the
4890 namespace would be <literal>http://www.loc.gov/zing/srw/v1.0/</literal>.
4893 When decoding, the <function>z_soap_codec</function>
4894 inspects the XML content
4895 and tries to match one of the services namespaces of the
4896 supplied handlers. If there is a match a handler function
4897 is invoked which decodes that particular SOAP package.
4898 If successful, the returned <literal>Z_SOAP</literal> package will be
4899 of type <literal>Z_SOAP_Generic</literal>.
4900 Member <literal>no</literal> is
4901 set the offset of handler that matched; <literal>ns</literal>
4902 is set to namespace of matching handler; the void pointer
4903 <literal>p</literal> is set to the C data structure assocatiated
4907 When a NULL namespace is met (member <literal>ns</literal> bwlow),
4908 that specifies end-of-list.
4911 Each handler is defined as follows:
4919 The <literal>ns</literal> is namespace of service associated with
4920 handler <literal>f</literal>. <literal>client_data</literal>
4921 is user-defined data which is passed to handler.
4924 The prototype for a SOAP service handler is:
4926 int handler(ODR o, void * ptr, void **handler_data,
4927 void *client_data, const char *ns);
4929 The <parameter>o</parameter> specifies the mode (decode/encode)
4930 as usual. The second argument, <parameter>ptr</parameter>,
4931 is a libxml2 tree node pointer (<literal>xmlNodePtr</literal>)
4932 and is a pointer to the <literal>Body</literal> element
4933 of the SOAP package. The <parameter>handler_data</parameter>
4934 is an opaque pointer to a C definitions associated with the
4935 SOAP service. <parameter>client_data</parameter> is the pointer
4936 which was set as part of the <literal>Z_SOAP_handler</literal>.
4937 Finally, <parameter>ns</parameter> the service namespace.
4940 <sect1 id="soap.srw">
4943 SRU SOAP is just one implementation of a SOAP handler as described
4944 in the previous section.
4945 The encoder/decoder handler for SRU is defined as
4948 #include <yaz/srw.h>
4950 int yaz_srw_codec(ODR o, void * pptr,
4951 Z_SRW_GDU **handler_data,
4952 void *client_data, const char *ns);
4954 Here, <literal>Z_SRW_GDU</literal> is either
4955 searchRetrieveRequest or a searchRetrieveResponse.
4959 The xQuery and xSortKeys are not handled yet by
4960 the SRW implementation of &yaz;. Explain is also missing.
4961 Future versions of &yaz; will include these features.
4965 The definition of searchRetrieveRequest is:
4969 #define Z_SRW_query_type_cql 1
4970 #define Z_SRW_query_type_xcql 2
4971 #define Z_SRW_query_type_pqf 3
4979 #define Z_SRW_sort_type_none 1
4980 #define Z_SRW_sort_type_sort 2
4981 #define Z_SRW_sort_type_xSort 3
4989 int *maximumRecords;
4991 char *recordPacking;
4993 } Z_SRW_searchRetrieveRequest;
4995 Please observe that data of type xsd:string is represented
4996 as a char pointer (<literal>char *</literal>). A null pointer
4997 means that the element is absent.
4998 Data of type xsd:integer is representd as a pointer to
4999 an int (<literal>int *</literal>). Again, a null pointer
5000 us used for absent elements.
5003 The SearchRetrieveResponse has the following definition.
5006 int * numberOfRecords;
5008 int * resultSetIdleTime;
5010 Z_SRW_record *records;
5013 Z_SRW_diagnostic *diagnostics;
5014 int num_diagnostics;
5015 int *nextRecordPosition;
5016 } Z_SRW_searchRetrieveResponse;
5018 The <literal>num_records</literal> and <literal>num_diagnostics</literal>
5019 is number of returned records and diagnostics respectively and also
5020 correspond to the "size of" arrays <literal>records</literal>
5021 and <literal>diagnostics</literal>.
5024 A retrieval record is defined as follows:
5028 char *recordData_buf;
5030 int *recordPosition;
5033 The record data is defined as a buffer of some length so that
5034 data can be of any type. SRW 1.0 currenly doesn't allow for this
5035 (only XML), but future versions might do.
5038 And, a diagnostic as:
5048 <chapter id="tools">
5049 <title>Supporting Tools</title>
5051 In support of the service API - primarily the ASN module, which
5052 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
5053 a collection of tools that support the development of applications.
5055 <sect1 id="tools.query">
5056 <title>Query Syntax Parsers</title>
5058 Since the type-1 (RPN) query structure has no direct, useful string
5059 representation, every origin application needs to provide some form of
5060 mapping from a local query notation or representation to a
5061 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
5062 construct the query manually, perhaps using
5063 <function>odr_malloc()</function> to simplify memory management.
5064 The &yaz; distribution includes three separate, query-generating tools
5065 that may be of use to you.
5068 <title>Prefix Query Format</title>
5070 Since RPN or reverse polish notation is really just a fancy way of
5071 describing a suffix notation format (operator follows operands), it
5072 would seem that the confusion is total when we now introduce a prefix
5073 notation for RPN. The reason is one of simple laziness - it's somewhat
5074 simpler to interpret a prefix format, and this utility was designed
5075 for maximum simplicity, to provide a baseline representation for use
5076 in simple test applications and scripting environments (like Tcl). The
5077 demonstration client included with YAZ uses the PQF.
5081 The PQF have been adopted by other parties developing Z39.50
5082 software. It is often referred to as Prefix Query Notation
5087 The PQF is defined by the pquery module in the YAZ library.
5088 There are two sets of function that have similar behavior. First
5089 set operates on a PQF parser handle, second set doesn't. First set
5090 set of functions are more flexible than the second set. Second set
5091 is obsolete and is only provided to ensure backwards compatibility.
5094 First set of functions all operate on a PQF parser handle:
5097 #include <yaz/pquery.h>
5099 YAZ_PQF_Parser yaz_pqf_create(void);
5101 void yaz_pqf_destroy(YAZ_PQF_Parser p);
5103 Z_RPNQuery *yaz_pqf_parse(YAZ_PQF_Parser p, ODR o, const char *qbuf);
5105 Z_AttributesPlusTerm *yaz_pqf_scan(YAZ_PQF_Parser p, ODR o,
5106 Odr_oid **attributeSetId, const char *qbuf);
5108 int yaz_pqf_error(YAZ_PQF_Parser p, const char **msg, size_t *off);
5111 A PQF parser is created and destructed by functions
5112 <function>yaz_pqf_create</function> and
5113 <function>yaz_pqf_destroy</function> respectively.
5114 Function <function>yaz_pqf_parse</function> parses query given
5115 by string <literal>qbuf</literal>. If parsing was successful,
5116 a Z39.50 RPN Query is returned which is created using ODR stream
5117 <literal>o</literal>. If parsing failed, a NULL pointer is
5119 Function <function>yaz_pqf_scan</function> takes a scan query in
5120 <literal>qbuf</literal>. If parsing was successful, the function
5121 returns attributes plus term pointer and modifies
5122 <literal>attributeSetId</literal> to hold attribute set for the
5123 scan request - both allocated using ODR stream <literal>o</literal>.
5124 If parsing failed, yaz_pqf_scan returns a NULL pointer.
5125 Error information for bad queries can be obtained by a call to
5126 <function>yaz_pqf_error</function> which returns an error code and
5127 modifies <literal>*msg</literal> to point to an error description,
5128 and modifies <literal>*off</literal> to the offset within last
5129 query were parsing failed.
5132 The second set of functions are declared as follows:
5135 #include <yaz/pquery.h>
5137 Z_RPNQuery *p_query_rpn(ODR o, oid_proto proto, const char *qbuf);
5139 Z_AttributesPlusTerm *p_query_scan(ODR o, oid_proto proto,
5140 Odr_oid **attributeSetP, const char *qbuf);
5142 int p_query_attset(const char *arg);
5145 The function <function>p_query_rpn()</function> takes as arguments an
5146 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
5147 to provide a memory source (the structure created is released on
5148 the next call to <function>odr_reset()</function> on the stream), a
5149 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
5150 <token>PROTO_SR</token>), an attribute set reference, and
5151 finally a null-terminated string holding the query string.
5154 If the parse went well, <function>p_query_rpn()</function> returns a
5155 pointer to a <literal>Z_RPNQuery</literal> structure which can be
5156 placed directly into a <literal>Z_SearchRequest</literal>.
5157 If parsing failed, due to syntax error, a NULL pointer is returned.
5160 The <literal>p_query_attset</literal> specifies which attribute set
5161 to use if the query doesn't specify one by the
5162 <literal>@attrset</literal> operator.
5163 The <literal>p_query_attset</literal> returns 0 if the argument is a
5164 valid attribute set specifier; otherwise the function returns -1.
5167 The grammar of the PQF is as follows:
5170 query ::= top-set query-struct.
5172 top-set ::= [ '@attrset' string ]
5174 query-struct ::= attr-spec | simple | complex | '@term' term-type query
5176 attr-spec ::= '@attr' [ string ] string query-struct
5178 complex ::= operator query-struct query-struct.
5180 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
5182 simple ::= result-set | term.
5184 result-set ::= '@set' string.
5188 proximity ::= exclusion distance ordered relation which-code unit-code.
5190 exclusion ::= '1' | '0' | 'void'.
5192 distance ::= integer.
5194 ordered ::= '1' | '0'.
5196 relation ::= integer.
5198 which-code ::= 'known' | 'private' | integer.
5200 unit-code ::= integer.
5202 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
5205 You will note that the syntax above is a fairly faithful
5206 representation of RPN, except for the Attribute, which has been
5207 moved a step away from the term, allowing you to associate one or more
5208 attributes with an entire query structure. The parser will
5209 automatically apply the given attributes to each term as required.
5212 The @attr operator is followed by an attribute specification
5213 (<literal>attr-spec</literal> above). The specification consists
5214 of an optional attribute set, an attribute type-value pair and
5215 a sub-query. The attribute type-value pair is packed in one string:
5216 an attribute type, an equals sign, and an attribute value, like this:
5217 <literal>@attr 1=1003</literal>.
5218 The type is always an integer but the value may be either an
5219 integer or a string (if it doesn't start with a digit character).
5220 A string attribute-value is encoded as a Type-1 ``complex''
5221 attribute with the list of values containing the single string
5222 specified, and including no semantic indicators.
5225 Version 3 of the Z39.50 specification defines various encoding of terms.
5226 Use <literal>@term </literal> <replaceable>type</replaceable>
5227 <replaceable>string</replaceable>,
5228 where type is one of: <literal>general</literal>,
5229 <literal>numeric</literal> or <literal>string</literal>
5230 (for InternationalString).
5231 If no term type has been given, the <literal>general</literal> form
5232 is used. This is the only encoding allowed in both versions 2 and 3
5233 of the Z39.50 standard.
5235 <sect3 id="PQF-prox">
5236 <title>Using Proximity Operators with PQF</title>
5239 This is an advanced topic, describing how to construct
5240 queries that make very specific requirements on the
5241 relative location of their operands.
5242 You may wish to skip this section and go straight to
5243 <link linkend="pqf-examples">the example PQF queries</link>.
5248 Most Z39.50 servers do not support proximity searching, or
5249 support only a small subset of the full functionality that
5250 can be expressed using the PQF proximity operator. Be
5251 aware that the ability to <emphasis>express</emphasis> a
5252 query in PQF is no guarantee that any given server will
5253 be able to <emphasis>execute</emphasis> it.
5259 The proximity operator <literal>@prox</literal> is a special
5260 and more restrictive version of the conjunction operator
5261 <literal>@and</literal>. Its semantics are described in
5262 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
5263 can be read on-line at
5264 <ulink url="&url.z39.50.proximity;"/>
5267 In PQF, the proximity operation is represented by a sequence
5270 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
5272 in which the meanings of the parameters are as described in in
5273 the standard, and they can take the following values:
5276 <formalpara><title>exclusion</title>
5278 0 = false (i.e. the proximity condition specified by the
5279 remaining parameters must be satisfied) or
5280 1 = true (the proximity condition specified by the
5281 remaining parameters must <emphasis>not</emphasis> be
5287 <formalpara><title>distance</title><para>
5288 An integer specifying the difference between the locations
5289 of the operands: e.g. two adjacent words would have
5290 distance=1 since their locations differ by one unit.
5292 </formalpara></listitem>
5294 <formalpara><title>ordered</title><para>
5295 1 = ordered (the operands must occur in the order the
5296 query specifies them) or
5297 0 = unordered (they may appear in either order).
5302 <formalpara><title>relation</title><para>
5303 Recognised values are
5305 2 (lessThanOrEqual),
5307 4 (greaterThanOrEqual),
5314 <formalpara><title>which-code</title><para>
5315 <literal>known</literal>
5317 <literal>k</literal>
5318 (the unit-code parameter is taken from the well-known list
5319 of alternatives described in below) or
5320 <literal>private</literal>
5322 <literal>p</literal>
5323 (the unit-code paramater has semantics specific to an
5324 out-of-band agreement such as a profile).
5329 <formalpara><title>unit-code</title><para>
5330 If the which-code parameter is <literal>known</literal>
5331 then the recognised values are
5341 10 (elementType) and
5343 If which-code is <literal>private</literal> then the
5344 acceptable values are determined by the profile.
5349 (The numeric values of the relation and well-known unit-code
5350 parameters are taken straight from
5351 <ulink url="&url.z39.50.proximity.asn1;"
5352 >the ASN.1</ulink> of the proximity structure in the standard.)
5355 <sect3 id="pqf-examples">
5356 <title>PQF queries</title>
5357 <example id="example.pqf.simple.terms">
5358 <title>PQF queries using simple terms</title>
5367 <example id="pqf.example.pqf.boolean.operators">
5368 <title>PQF boolean operators</title>
5371 @or "dylan" "zimmerman"
5373 @and @or dylan zimmerman when
5375 @and when @or dylan zimmerman
5379 <example id="example.pqf.result.sets">
5380 <title>PQF references to result sets</title>
5385 @and @set seta @set setb
5389 <example id="example.pqf.attributes">
5390 <title>Attributes for terms</title>
5395 @attr 1=4 @attr 4=1 "self portrait"
5397 @attrset exp1 @attr 1=1 CategoryList
5399 @attr gils 1=2008 Copenhagen
5401 @attr 1=/book/title computer
5405 <example id="example.pqf.proximity">
5406 <title>PQF Proximity queries</title>
5409 @prox 0 3 1 2 k 2 dylan zimmerman
5411 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
5412 distance, ordered, relation, which-code and unit-code, in that
5416 <para>exclusion = 0: the proximity condition must hold</para>
5419 <para>distance = 3: the terms must be three units apart</para>
5423 ordered = 1: they must occur in the order they are specified
5428 relation = 2: lessThanOrEqual (to the distance of 3 units)
5433 which-code is ``known'', so the standard unit-codes are used
5437 <para>unit-code = 2: word.</para>
5440 So the whole proximity query means that the words
5441 <literal>dylan</literal> and <literal>zimmerman</literal> must
5442 both occur in the record, in that order, differing in position
5443 by three or fewer words (i.e. with two or fewer words between
5444 them.) The query would find ``Bob Dylan, aka. Robert
5445 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
5446 since the distance in this case is four.
5449 <example id="example.pqf.search.term.type">
5450 <title>PQF specification of search term type</title>
5453 @term string "a UTF-8 string, maybe?"
5457 <example id="example.pqf.mixed.queries">
5458 <title>PQF mixed queries</title>
5461 @or @and bob dylan @set Result-1
5463 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
5465 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
5467 The last of these examples is a spatial search: in
5468 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
5469 >the GILS attribute set</ulink>,
5471 2038 indicates West Bounding Coordinate and
5472 2030 indicates East Bounding Coordinate,
5473 so the query is for areas extending from -114 degrees
5474 to no more than -109 degrees.
5479 <sect2 id="CCL"><title>CCL</title>
5481 Not all users enjoy typing in prefix query structures and numerical
5482 attribute values, even in a minimalistic test client. In the library
5483 world, the more intuitive Common Command Language - CCL (ISO 8777)
5484 has enjoyed some popularity - especially before the widespread
5485 availability of graphical interfaces. It is still useful in
5486 applications where you for some reason or other need to provide a
5487 symbolic language for expressing boolean query structures.
5489 <sect3 id="ccl.syntax">
5490 <title>CCL Syntax</title>
5492 The CCL parser obeys the following grammar for the FIND argument.
5493 The syntax is annotated by in the lines prefixed by
5494 <literal>--</literal>.
5497 CCL-Find ::= CCL-Find Op Elements
5500 Op ::= "and" | "or" | "not"
5501 -- The above means that Elements are separated by boolean operators.
5503 Elements ::= '(' CCL-Find ')'
5506 | Qualifiers Relation Terms
5507 | Qualifiers Relation '(' CCL-Find ')'
5508 | Qualifiers '=' string '-' string
5509 -- Elements is either a recursive definition, a result set reference, a
5510 -- list of terms, qualifiers followed by terms, qualifiers followed
5511 -- by a recursive definition or qualifiers in a range (lower - upper).
5513 Set ::= 'set' = string
5514 -- Reference to a result set
5516 Terms ::= Terms Prox Term
5518 -- Proximity of terms.
5520 Term ::= Term string
5522 -- This basically means that a term may include a blank
5524 Qualifiers ::= Qualifiers ',' string
5526 -- Qualifiers is a list of strings separated by comma
5528 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
5529 -- Relational operators. This really doesn't follow the ISO8777
5533 -- Proximity operator
5536 <example id="example.ccl.queries">
5537 <title>CCL queries</title>
5539 The following queries are all valid:
5550 (dylan and bob) or set=1
5559 Assuming that the qualifiers <literal>ti</literal>,
5560 <literal>au</literal>
5561 and <literal>date</literal> are defined we may use:
5566 au=(bob dylan and slow train coming)
5568 date>1980 and (ti=((self portrait)))
5572 <sect3 id="ccl.qualifiers">
5573 <title>CCL Qualifiers</title>
5575 Qualifiers are used to direct the search to a particular searchable
5576 index, such as title (ti) and author indexes (au). The CCL standard
5577 itself doesn't specify a particular set of qualifiers, but it does
5578 suggest a few short-hand notations. You can customize the CCL parser
5579 to support a particular set of qualifiers to reflect the current target
5580 profile. Traditionally, a qualifier would map to a particular
5581 use-attribute within the BIB-1 attribute set. It is also
5582 possible to set other attributes, such as the structure
5586 A CCL profile is a set of predefined CCL qualifiers that may be
5587 read from a file or set in the CCL API.
5588 The YAZ client reads its CCL qualifiers from a file named
5589 <filename>default.bib</filename>. There are four types of
5590 lines in a CCL profile: qualifier specification,
5591 qualifier alias, comments and directives.
5593 <sect4 id="ccl.qualifier.specification">
5594 <title>Qualifier specification</title>
5596 A qualifier specification is of the form:
5599 <replaceable>qualifier-name</replaceable>
5600 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
5601 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
5604 where <replaceable>qualifier-name</replaceable> is the name of the
5605 qualifier to be used (eg. <literal>ti</literal>),
5606 <replaceable>type</replaceable> is attribute type in the attribute
5607 set (Bib-1 is used if no attribute set is given) and
5608 <replaceable>val</replaceable> is attribute value.
5609 The <replaceable>type</replaceable> can be specified as an
5610 integer or as it be specified either as a single-letter:
5611 <literal>u</literal> for use,
5612 <literal>r</literal> for relation,<literal>p</literal> for position,
5613 <literal>s</literal> for structure,<literal>t</literal> for truncation
5614 or <literal>c</literal> for completeness.
5615 The attributes for the special qualifier name <literal>term</literal>
5616 are used when no CCL qualifier is given in a query.
5617 <table id="ccl.common.bib1.attributes">
5618 <title>Common Bib-1 attributes</title>
5620 <colspec colwidth="2*" colname="type"></colspec>
5621 <colspec colwidth="9*" colname="description"></colspec>
5625 <entry>Description</entry>
5630 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
5632 Use attribute (1). Common use attributes are
5633 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
5634 62 Subject, 1003 Author), 1016 Any. Specify value
5639 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
5641 Relation attribute (2). Common values are
5642 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
5643 100 phonetic, 101 stem, 102 relevance, 103 always matches.
5647 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
5649 Position attribute (3). Values: 1 first in field, 2
5650 first in any subfield, 3 any position in field.
5654 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
5656 Structure attribute (4). Values: 1 phrase, 2 word,
5657 3 key, 4 year, 5 date, 6 word list, 100 date (un),
5658 101 name (norm), 102 name (un), 103 structure, 104 urx,
5659 105 free-form-text, 106 document-text, 107 local-number,
5660 108 string, 109 numeric string.
5664 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
5666 Truncation attribute (5). Values: 1 right, 2 left,
5667 3 left& right, 100 none, 101 process #, 102 regular-1,
5668 103 regular-2, 104 CCL.
5672 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
5674 Completeness attribute (6). Values: 1 incomplete subfield,
5675 2 complete subfield, 3 complete field.
5683 Refer to <xref linkend="bib1"/> or the complete
5684 <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
5687 It is also possible to specify non-numeric attribute values,
5688 which are used in combination with certain types.
5689 The special combinations are:
5690 <table id="ccl.special.attribute.combos">
5691 <title>Special attribute combos</title>
5693 <colspec colwidth="2*" colname="name"></colspec>
5694 <colspec colwidth="9*" colname="description"></colspec>
5698 <entry>Description</entry>
5703 <entry><literal>s=pw</literal></entry>
5705 The structure is set to either word or phrase depending
5706 on the number of tokens in a term (phrase-word).
5710 <entry><literal>s=al</literal></entry>
5712 Each token in the term is ANDed. (and-list).
5713 This does not set the structure at all.
5716 <row><entry><literal>s=ol</literal></entry>
5718 Each token in the term is ORed. (or-list).
5719 This does not set the structure at all.
5722 <row><entry><literal>s=ag</literal></entry>
5724 Tokens that appears as phrases (with blank in them) gets
5725 structure phrase attached (4=1). Tokens that appear to be words
5726 gets structure word attached (4=2). Phrases and words are
5727 ANDed. This is a variant of s=al and s=pw, with the main
5728 difference that words are not split (with operator AND)
5729 but instead kept in one RPN token. This facility appeared
5733 <row><entry><literal>r=o</literal></entry>
5735 Allows ranges and the operators greather-than, less-than, ...
5737 This sets Bib-1 relation attribute accordingly (relation
5738 ordered). A query construct is only treated as a range if
5739 dash is used and that is surrounded by white-space. So
5740 <literal>-1980</literal> is treated as term
5741 <literal>"-1980"</literal> not <literal><= 1980</literal>.
5742 If <literal>- 1980</literal> is used, however, that is
5746 <row><entry><literal>r=r</literal></entry>
5748 Similar to <literal>r=o</literal> but assumes that terms
5749 are non-negative (not prefixed with <literal>-</literal>).
5750 Thus, a dash will always be treated as a range.
5751 The construct <literal>1980-1990</literal> is
5752 treated as a range with <literal>r=r</literal> but as a
5753 single term <literal>"1980-1990"</literal> with
5754 <literal>r=o</literal>. The special attribute
5755 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
5758 <row><entry><literal>r=omiteq</literal></entry>
5760 This will omit relation=equals (@attr 2=3) when r=o / r=r
5761 is used. This is useful for servers that somehow breaks
5762 when an explicit relation=equals is used. Omitting the
5763 relation is usually safe because "equals" is the default
5764 behavior. This tweak was added in YAZ version 5.1.2.
5767 <row><entry><literal>t=l</literal></entry>
5769 Allows term to be left-truncated.
5770 If term is of the form <literal>?x</literal>, the resulting
5771 Type-1 term is <literal>x</literal> and truncation is left.
5774 <row><entry><literal>t=r</literal></entry>
5776 Allows term to be right-truncated.
5777 If term is of the form <literal>x?</literal>, the resulting
5778 Type-1 term is <literal>x</literal> and truncation is right.
5781 <row><entry><literal>t=n</literal></entry>
5783 If term is does not include <literal>?</literal>, the
5784 truncation attribute is set to none (100).
5787 <row><entry><literal>t=b</literal></entry>
5789 Allows term to be both left&right truncated.
5790 If term is of the form <literal>?x?</literal>, the
5791 resulting term is <literal>x</literal> and trunctation is
5792 set to both left&right.
5795 <row><entry><literal>t=x</literal></entry>
5797 Allows masking anywhere in a term, thus fully supporting
5798 # (mask one character) and ? (zero or more of any).
5799 If masking is used, trunction is set to 102 (regexp-1 in term)
5800 and the term is converted accordingly to a regular expression.
5803 <row><entry><literal>t=z</literal></entry>
5805 Allows masking anywhere in a term, thus fully supporting
5806 # (mask one character) and ? (zero or more of any).
5807 If masking is used, trunction is set to 104 (Z39.58 in term)
5808 and the term is converted accordingly to Z39.58 masking term -
5809 actually the same truncation as CCL itself.
5816 <example id="example.ccl.profile">
5817 <title>CCL profile</title>
5819 Consider the following definition:
5829 <literal>ti</literal> and <literal>au</literal> both set
5830 structure attribute to phrase (s=1).
5831 <literal>ti</literal>
5832 sets the use-attribute to 4. <literal>au</literal> sets the
5834 When no qualifiers are used in the query the structure-attribute is
5835 set to free-form-text (105) (rule for <literal>term</literal>).
5836 The <literal>date</literal> sets the relation attribute to
5837 the relation used in the CCL query and sets the use attribute
5841 You can combine attributes. To Search for "ranked title" you
5844 ti,ranked=knuth computer
5846 which will set relation=ranked, use=title, structure=phrase.
5853 is a valid query. But
5861 <sect4 id="ccl.qualifier.alias">
5862 <title>Qualifier alias</title>
5864 A qualifier alias is of the form:
5867 <replaceable>q</replaceable>
5868 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
5871 which declares <replaceable>q</replaceable> to
5872 be an alias for <replaceable>q1</replaceable>,
5873 <replaceable>q2</replaceable>... such that the CCL
5874 query <replaceable>q=x</replaceable> is equivalent to
5875 <replaceable>q1=x or q2=x or ...</replaceable>.
5878 <sect4 id="ccl.comments">
5879 <title>Comments</title>
5881 Lines with white space or lines that begin with
5882 character <literal>#</literal> are treated as comments.
5885 <sect4 id="ccl.directives">
5886 <title>Directives</title>
5888 Directive specifications takes the form
5890 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
5892 <table id="ccl.directives.table">
5893 <title>CCL directives</title>
5895 <colspec colwidth="2*" colname="name"></colspec>
5896 <colspec colwidth="8*" colname="description"></colspec>
5897 <colspec colwidth="1*" colname="default"></colspec>
5901 <entry>Description</entry>
5902 <entry>Default</entry>
5907 <entry>truncation</entry>
5908 <entry>Truncation character</entry>
5909 <entry><literal>?</literal></entry>
5913 <entry>Masking character. Requires YAZ 4.2.58 or later</entry>
5914 <entry><literal>#</literal></entry>
5917 <entry>field</entry>
5918 <entry>Specifies how multiple fields are to be
5919 combined. There are two modes: <literal>or</literal>:
5920 multiple qualifier fields are ORed,
5921 <literal>merge</literal>: attributes for the qualifier
5922 fields are merged and assigned to one term.
5924 <entry><literal>merge</literal></entry>
5928 <entry>Specifies if CCL operators and qualifiers should be
5929 compared with case sensitivity or not. Specify 1 for
5930 case sensitive; 0 for case insensitive.</entry>
5931 <entry><literal>1</literal></entry>
5935 <entry>Specifies token for CCL operator AND.</entry>
5936 <entry><literal>and</literal></entry>
5940 <entry>Specifies token for CCL operator OR.</entry>
5941 <entry><literal>or</literal></entry>
5945 <entry>Specifies token for CCL operator NOT.</entry>
5946 <entry><literal>not</literal></entry>
5950 <entry>Specifies token for CCL operator SET.</entry>
5951 <entry><literal>set</literal></entry>
5958 <sect3 id="ccl.api">
5959 <title>CCL API</title>
5961 All public definitions can be found in the header file
5962 <filename>ccl.h</filename>. A profile identifier is of type
5963 <literal>CCL_bibset</literal>. A profile must be created with the call
5964 to the function <function>ccl_qual_mk</function> which returns a profile
5965 handle of type <literal>CCL_bibset</literal>.
5968 To read a file containing qualifier definitions the function
5969 <function>ccl_qual_file</function> may be convenient. This function
5970 takes an already opened <literal>FILE</literal> handle pointer as
5971 argument along with a <literal>CCL_bibset</literal> handle.
5974 To parse a simple string with a FIND query use the function
5977 struct ccl_rpn_node *ccl_find_str(CCL_bibset bibset, const char *str,
5978 int *error, int *pos);
5981 which takes the CCL profile (<literal>bibset</literal>) and query
5982 (<literal>str</literal>) as input. Upon successful completion the RPN
5983 tree is returned. If an error occur, such as a syntax error, the integer
5984 pointed to by <literal>error</literal> holds the error code and
5985 <literal>pos</literal> holds the offset inside query string in which
5989 An English representation of the error may be obtained by calling
5990 the <literal>ccl_err_msg</literal> function. The error codes are
5991 listed in <filename>ccl.h</filename>.
5994 To convert the CCL RPN tree (type
5995 <literal>struct ccl_rpn_node *</literal>)
5996 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
5997 must be used. This function which is part of YAZ is implemented in
5998 <filename>yaz-ccl.c</filename>.
5999 After calling this function the CCL RPN tree is probably no longer
6000 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
6003 A CCL profile may be destroyed by calling the
6004 <function>ccl_qual_rm</function> function.
6007 The token names for the CCL operators may be changed by setting the
6008 globals (all type <literal>char *</literal>)
6009 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
6010 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
6011 An operator may have aliases, i.e. there may be more than one name for
6012 the operator. To do this, separate each alias with a space character.
6019 <ulink url="&url.cql;">CQL</ulink>
6020 - Common Query Language - was defined for the
6021 <ulink url="&url.sru;">SRU</ulink> protocol.
6022 In many ways CQL has a similar syntax to CCL.
6023 The objective of CQL is different. Where CCL aims to be
6024 an end-user language, CQL is <emphasis>the</emphasis> protocol
6025 query language for SRU.
6029 If you are new to CQL, read the
6030 <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
6034 The CQL parser in &yaz; provides the following:
6038 It parses and validates a CQL query.
6043 It generates a C structure that allows you to convert
6044 a CQL query to some other query language, such as SQL.
6049 The parser converts a valid CQL query to PQF, thus providing a
6050 way to use CQL for both SRU servers and Z39.50 targets at the
6056 The parser converts CQL to XCQL.
6057 XCQL is an XML representation of CQL.
6058 XCQL is part of the SRU specification. However, since SRU
6059 supports CQL only, we don't expect XCQL to be widely used.
6060 Furthermore, CQL has the advantage over XCQL that it is
6066 <sect3 id="cql.parsing">
6067 <title>CQL parsing</title>
6069 A CQL parser is represented by the <literal>CQL_parser</literal>
6070 handle. Its contents should be considered &yaz; internal (private).
6072 #include <yaz/cql.h>
6074 typedef struct cql_parser *CQL_parser;
6076 CQL_parser cql_parser_create(void);
6077 void cql_parser_destroy(CQL_parser cp);
6079 A parser is created by <function>cql_parser_create</function> and
6080 is destroyed by <function>cql_parser_destroy</function>.
6083 To parse a CQL query string, the following function
6086 int cql_parser_string(CQL_parser cp, const char *str);
6088 A CQL query is parsed by the <function>cql_parser_string</function>
6089 which takes a query <parameter>str</parameter>.
6090 If the query was valid (no syntax errors), then zero is returned;
6091 otherwise -1 is returned to indicate a syntax error.
6095 int cql_parser_stream(CQL_parser cp,
6096 int (*getbyte)(void *client_data),
6097 void (*ungetbyte)(int b, void *client_data),
6100 int cql_parser_stdio(CQL_parser cp, FILE *f);
6102 The functions <function>cql_parser_stream</function> and
6103 <function>cql_parser_stdio</function> parses a CQL query
6104 - just like <function>cql_parser_string</function>.
6105 The only difference is that the CQL query can be
6106 fed to the parser in different ways.
6107 The <function>cql_parser_stream</function> uses a generic
6108 byte stream as input. The <function>cql_parser_stdio</function>
6109 uses a <literal>FILE</literal> handle which is opened for reading.
6112 <sect3 id="cql.tree">
6113 <title>CQL tree</title>
6115 The the query string is valid, the CQL parser
6116 generates a tree representing the structure of the
6121 struct cql_node *cql_parser_result(CQL_parser cp);
6123 <function>cql_parser_result</function> returns the
6124 a pointer to the root node of the resulting tree.
6127 Each node in a CQL tree is represented by a
6128 <literal>struct cql_node</literal>.
6129 It is defined as follows:
6131 #define CQL_NODE_ST 1
6132 #define CQL_NODE_BOOL 2
6133 #define CQL_NODE_SORT 3
6143 struct cql_node *modifiers;
6147 struct cql_node *left;
6148 struct cql_node *right;
6149 struct cql_node *modifiers;
6153 struct cql_node *next;
6154 struct cql_node *modifiers;
6155 struct cql_node *search;
6160 There are three node types: search term (ST), boolean (BOOL)
6162 A modifier is treated as a search term too.
6165 The search term node has five members:
6169 <literal>index</literal>: index for search term.
6170 If an index is unspecified for a search term,
6171 <literal>index</literal> will be NULL.
6176 <literal>index_uri</literal>: index URi for search term
6177 or NULL if none could be resolved for the index.
6182 <literal>term</literal>: the search term itself.
6187 <literal>relation</literal>: relation for search term.
6192 <literal>relation_uri</literal>: relation URI for search term.
6197 <literal>modifiers</literal>: relation modifiers for search
6198 term. The <literal>modifiers</literal> list itself of cql_nodes
6199 each of type <literal>ST</literal>.
6205 The boolean node represents <literal>and</literal>,
6206 <literal>or</literal>, <literal>not</literal> +
6211 <literal>left</literal> and <literal>right</literal>: left
6212 - and right operand respectively.
6217 <literal>modifiers</literal>: proximity arguments.
6223 The sort node represents both the SORTBY clause.
6226 <sect3 id="cql.to.pqf">
6227 <title>CQL to PQF conversion</title>
6229 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
6230 that the resulting RPN depends on the Z39.50 target
6231 capabilities (combinations of supported attributes).
6232 In addition, the CQL and SRU operates on index prefixes
6233 (URI or strings), whereas the RPN uses Object Identifiers
6237 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
6238 type. It represents a particular mapping between CQL and RPN.
6239 This handle is created and destroyed by the functions:
6241 cql_transform_t cql_transform_open_FILE (FILE *f);
6242 cql_transform_t cql_transform_open_fname(const char *fname);
6243 void cql_transform_close(cql_transform_t ct);
6245 The first two functions create a tranformation handle from
6246 either an already open FILE or from a filename respectively.
6249 The handle is destroyed by <function>cql_transform_close</function>
6250 in which case no further reference of the handle is allowed.
6253 When a <literal>cql_transform_t</literal> handle has been created
6254 you can convert to RPN.
6256 int cql_transform_buf(cql_transform_t ct,
6257 struct cql_node *cn, char *out, int max);
6259 This function converts the CQL tree <literal>cn</literal>
6260 using handle <literal>ct</literal>.
6261 For the resulting PQF, you supply a buffer <literal>out</literal>
6262 which must be able to hold at at least <literal>max</literal>
6266 If conversion failed, <function>cql_transform_buf</function>
6267 returns a non-zero SRU error code; otherwise zero is returned
6268 (conversion successful). The meanings of the numeric error
6269 codes are listed in the SRU specification somewhere (no
6270 direct link anymore).
6273 If conversion fails, more information can be obtained by calling
6275 int cql_transform_error(cql_transform_t ct, char **addinfop);
6277 This function returns the most recently returned numeric
6278 error-code and sets the string-pointer at
6279 <literal>*addinfop</literal> to point to a string containing
6280 additional information about the error that occurred: for
6281 example, if the error code is 15 (``Illegal or unsupported context
6282 set''), the additional information is the name of the requested
6283 context set that was not recognised.
6286 The SRU error-codes may be translated into brief human-readable
6287 error messages using
6289 const char *cql_strerror(int code);
6293 If you wish to be able to produce a PQF result in a different
6294 way, there are two alternatives.
6296 void cql_transform_pr(cql_transform_t ct,
6297 struct cql_node *cn,
6298 void (*pr)(const char *buf, void *client_data),
6301 int cql_transform_FILE(cql_transform_t ct,
6302 struct cql_node *cn, FILE *f);
6304 The former function produces output to a user-defined
6305 output stream. The latter writes the result to an already
6306 open <literal>FILE</literal>.
6309 <sect3 id="cql.to.rpn">
6310 <title>Specification of CQL to RPN mappings</title>
6312 The file supplied to functions
6313 <function>cql_transform_open_FILE</function>,
6314 <function>cql_transform_open_fname</function> follows
6315 a structure found in many Unix utilities.
6316 It consists of mapping specifications - one per line.
6317 Lines starting with <literal>#</literal> are ignored (comments).
6320 Each line is of the form
6322 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
6326 An RPN pattern is a simple attribute list. Each attribute pair
6329 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
6331 The attribute <replaceable>set</replaceable> is optional.
6332 The <replaceable>type</replaceable> is the attribute type,
6333 <replaceable>value</replaceable> the attribute value.
6336 The character <literal>*</literal> (asterisk) has special meaning
6337 when used in the RPN pattern.
6338 Each occurrence of <literal>*</literal> is substituted with the
6339 CQL matching name (index, relation, qualifier etc).
6340 This facility can be used to copy a CQL name verbatim to the RPN result.
6343 The following CQL patterns are recognized:
6347 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6351 This pattern is invoked when a CQL index, such as
6352 dc.title is converted. <replaceable>set</replaceable>
6353 and <replaceable>name</replaceable> are the context set and index
6355 Typically, the RPN specifies an equivalent use attribute.
6358 For terms not bound by an index the pattern
6359 <literal>index.cql.serverChoice</literal> is used.
6360 Here, the prefix <literal>cql</literal> is defined as
6361 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
6362 If this pattern is not defined, the mapping will fail.
6366 <literal>index.</literal><replaceable>set</replaceable><literal>.*</literal>
6367 is used when no other index pattern is matched.
6373 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6378 For backwards compatibility, this is recognised as a synonym of
6379 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
6385 <literal>relation.</literal><replaceable>relation</replaceable>
6389 This pattern specifies how a CQL relation is mapped to RPN.
6390 <replaceable>pattern</replaceable> is name of relation
6391 operator. Since <literal>=</literal> is used as
6392 separator between CQL pattern and RPN, CQL relations
6393 including <literal>=</literal> cannot be
6394 used directly. To avoid a conflict, the names
6395 <literal>ge</literal>,
6396 <literal>eq</literal>,
6397 <literal>le</literal>,
6398 must be used for CQL operators, greater-than-or-equal,
6399 equal, less-than-or-equal respectively.
6400 The RPN pattern is supposed to include a relation attribute.
6403 For terms not bound by a relation, the pattern
6404 <literal>relation.scr</literal> is used. If the pattern
6405 is not defined, the mapping will fail.
6408 The special pattern, <literal>relation.*</literal> is used
6409 when no other relation pattern is matched.
6415 <literal>relationModifier.</literal><replaceable>mod</replaceable>
6419 This pattern specifies how a CQL relation modifier is mapped to RPN.
6420 The RPN pattern is usually a relation attribute.
6426 <literal>structure.</literal><replaceable>type</replaceable>
6430 This pattern specifies how a CQL structure is mapped to RPN.
6431 Note that this CQL pattern is somewhat to similar to
6432 CQL pattern <literal>relation</literal>.
6433 The <replaceable>type</replaceable> is a CQL relation.
6436 The pattern, <literal>structure.*</literal> is used
6437 when no other structure pattern is matched.
6438 Usually, the RPN equivalent specifies a structure attribute.
6444 <literal>position.</literal><replaceable>type</replaceable>
6448 This pattern specifies how the anchor (position) of
6449 CQL is mapped to RPN.
6450 The <replaceable>type</replaceable> is one
6451 of <literal>first</literal>, <literal>any</literal>,
6452 <literal>last</literal>, <literal>firstAndLast</literal>.
6455 The pattern, <literal>position.*</literal> is used
6456 when no other position pattern is matched.
6462 <literal>set.</literal><replaceable>prefix</replaceable>
6466 This specification defines a CQL context set for a given prefix.
6467 The value on the right hand side is the URI for the set -
6468 <emphasis>not</emphasis> RPN. All prefixes used in
6469 index patterns must be defined this way.
6475 <literal>set</literal>
6479 This specification defines a default CQL context set for index names.
6480 The value on the right hand side is the URI for the set.
6486 <example id="example.cql.to.rpn.mapping">
6487 <title>CQL to RPN mapping file</title>
6489 This simple file defines two context sets, three indexes and three
6490 relations, a position pattern and a default structure.
6492 <programlisting><![CDATA[
6493 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
6494 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
6496 index.cql.serverChoice = 1=1016
6497 index.dc.title = 1=4
6498 index.dc.subject = 1=21
6504 position.any = 3=3 6=1
6510 With the mappings above, the CQL query
6514 is converted to the PQF:
6516 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
6518 by rules <literal>index.cql.serverChoice</literal>,
6519 <literal>relation.scr</literal>, <literal>structure.*</literal>,
6520 <literal>position.any</literal>.
6527 is rejected, since <literal>position.right</literal> is
6533 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
6537 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
6541 <example id="example.cql.to.rpn.string">
6542 <title>CQL to RPN string attributes</title>
6544 In this example we allow any index to be passed to RPN as
6547 <programlisting><![CDATA[
6548 # Identifiers for prefixes used in this file. (index.*)
6549 set.cql = info:srw/cql-context-set/1/cql-v1.1
6550 set.rpn = http://bogus/rpn
6551 set = http://bogus/rpn
6553 # The default index when none is specified by the query
6554 index.cql.serverChoice = 1=any
6563 The <literal>http://bogus/rpn</literal> context set is also the default
6564 so we can make queries such as
6568 which is converted to
6570 @attr 2=3 @attr 4=1 @attr 3=3 @attr 1=title "a"
6574 <example id="example.cql.to.rpn.bathprofile">
6575 <title>CQL to RPN using Bath Profile</title>
6577 The file <filename>etc/pqf.properties</filename> has mappings from
6578 the Bath Profile and Dublin Core to RPN.
6579 If YAZ is installed as a package it's usually located
6580 in <filename>/usr/share/yaz/etc</filename> and part of the
6581 development package, such as <literal>libyaz-dev</literal>.
6585 <sect3 id="cql.xcql">
6586 <title>CQL to XCQL conversion</title>
6588 Conversion from CQL to XCQL is trivial and does not
6589 require a mapping to be defined.
6590 There three functions to choose from depending on the
6591 way you wish to store the resulting output (XML buffer
6594 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
6595 void cql_to_xml(struct cql_node *cn,
6596 void (*pr)(const char *buf, void *client_data),
6598 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
6600 Function <function>cql_to_xml_buf</function> converts
6601 to XCQL and stores result in a user supplied buffer of a given
6605 <function>cql_to_xml</function> writes the result in
6606 a user defined output stream.
6607 <function>cql_to_xml_stdio</function> writes to a
6611 <sect3 id="rpn.to.cql">
6612 <title>PQF to CQL conversion</title>
6614 Conversion from PQF to CQL is offered by the two functions shown
6615 below. The former uses a generic stream for result. The latter
6616 puts result in a WRBUF (string container).
6618 #include <yaz/rpn2cql.h>
6620 int cql_transform_rpn2cql_stream(cql_transform_t ct,
6621 void (*pr)(const char *buf, void *client_data),
6625 int cql_transform_rpn2cql_wrbuf(cql_transform_t ct,
6629 The configuration is the same as used in CQL to PQF conversions.
6634 <sect1 id="tools.oid">
6635 <title>Object Identifiers</title>
6637 The basic YAZ representation of an OID is an array of integers,
6638 terminated with the value -1. This integer is of type
6639 <literal>Odr_oid</literal>.
6642 Fundamental OID operations and the type <literal>Odr_oid</literal>
6643 are defined in <filename>yaz/oid_util.h</filename>.
6646 An OID can either be declared as a automatic variable or it can
6647 allocated using the memory utilities or ODR/NMEM. It's
6648 guaranteed that an OID can fit in <literal>OID_SIZE</literal> integers.
6650 <example id="tools.oid.bib1.1"><title>Create OID on stack</title>
6652 We can create an OID for the Bib-1 attribute set with:
6654 Odr_oid bib1[OID_SIZE];
6666 And OID may also be filled from a string-based representation using
6667 dots (.). This is achieved by function
6669 int oid_dotstring_to_oid(const char *name, Odr_oid *oid);
6671 This functions returns 0 if name could be converted; -1 otherwise.
6673 <example id="tools.oid.bib1.2"><title>Using oid_oiddotstring_to_oid</title>
6675 We can fill the Bib-1 attribute set OID easier with:
6677 Odr_oid bib1[OID_SIZE];
6678 oid_oiddotstring_to_oid("1.2.840.10003.3.1", bib1);
6683 We can also allocate an OID dynamically on a ODR stream with:
6685 Odr_oid *odr_getoidbystr(ODR o, const char *str);
6687 This creates an OID from string-based representation using dots.
6688 This function take an &odr; stream as parameter. This stream is used to
6689 allocate memory for the data elements, which is released on a
6690 subsequent call to <function>odr_reset()</function> on that stream.
6692 <example id="tools.oid.bib1.3">
6693 <title>Using odr_getoidbystr</title>
6695 We can create a OID for the Bib-1 attribute set with:
6697 Odr_oid *bib1 = odr_getoidbystr(odr, "1.2.840.10003.3.1");
6704 char *oid_oid_to_dotstring(const Odr_oid *oid, char *oidbuf)
6706 does the reverse of <function>oid_oiddotstring_to_oid</function>. It
6707 converts an OID to the string-based representation using dots.
6708 The supplied char buffer <literal>oidbuf</literal> holds the resulting
6709 string and must be at least <literal>OID_STR_MAX</literal> in size.
6712 OIDs can be copied with <function>oid_oidcpy</function> which takes
6713 two OID lists as arguments. Alternativly, an OID copy can be allocated
6714 on a ODR stream with:
6716 Odr_oid *odr_oiddup(ODR odr, const Odr_oid *o);
6720 OIDs can be compared with <function>oid_oidcmp</function> which returns
6721 zero if the two OIDs provided are identical; non-zero otherwise.
6723 <sect2 id="tools.oid.database">
6724 <title>OID database</title>
6726 From YAZ version 3 and later, the oident system has been replaced
6727 by an OID database. OID database is a misnomer .. the old odient
6728 system was also a database.
6731 The OID database is really just a map between named Object Identifiers
6732 (string) and their OID raw equivalents. Most operations either
6733 convert from string to OID or other way around.
6736 Unfortunately, whenever we supply a string we must also specify the
6737 <emphasis>OID class</emphasis>. The class is necessary because some
6738 strings correspond to multiple OIDs. An example of such a string is
6739 <literal>Bib-1</literal> which may either be an attribute-set
6740 or a diagnostic-set.
6743 Applications using the YAZ database should include
6744 <filename>yaz/oid_db.h</filename>.
6747 A YAZ database handle is of type <literal>yaz_oid_db_t</literal>.
6748 Actually that's a pointer. You need not think deal with that.
6749 YAZ has a built-in database which can be considered "constant" for
6751 We can get hold that by using function <function>yaz_oid_std</function>.
6754 All functions with prefix <function>yaz_string_to_oid</function>
6755 converts from class + string to OID. We have variants of this
6756 operation due to different memory allocation strategies.
6759 All functions with prefix
6760 <function>yaz_oid_to_string</function> converts from OID to string
6763 <example id="tools.oid.bib1.4">
6764 <title>Create OID with YAZ DB</title>
6766 We can create an OID for the Bib-1 attribute set on the ODR stream
6770 yaz_string_to_oid_odr(yaz_oid_std(), CLASS_ATTSET, "Bib-1", odr);
6772 This is more complex than using <function>odr_getoidbystr</function>.
6773 You would only use <function>yaz_string_to_oid_odr</function> when the
6774 string (here Bib-1) is supplied by a user or configuration.
6778 <sect2 id="tools.oid.std">
6779 <title>Standard OIDs</title>
6781 All the object identifers in the standard OID database as returned
6782 by <function>yaz_oid_std</function> can referenced directly in a
6783 program as a constant OID.
6784 Each constant OID is prefixed with <literal>yaz_oid_</literal> -
6785 followed by OID class (lowercase) - then by OID name (normalized and
6789 See <xref linkend="list-oids"/> for list of all object identifiers
6791 These are declared in <filename>yaz/oid_std.h</filename> but are
6792 included by <filename>yaz/oid_db.h</filename> as well.
6794 <example id="tools.oid.bib1.5">
6795 <title>Use a built-in OID</title>
6797 We can allocate our own OID filled with the constant OID for
6800 Odr_oid *bib1 = odr_oiddup(o, yaz_oid_attset_bib1);
6806 <sect1 id="tools.nmem">
6807 <title>Nibble Memory</title>
6809 Sometimes when you need to allocate and construct a large,
6810 interconnected complex of structures, it can be a bit of a pain to
6811 release the associated memory again. For the structures describing the
6812 Z39.50 PDUs and related structures, it is convenient to use the
6813 memory-management system of the &odr; subsystem (see
6814 <xref linkend="odr.use"/>). However, in some circumstances
6815 where you might otherwise benefit from using a simple nibble memory
6816 management system, it may be impractical to use
6817 <function>odr_malloc()</function> and <function>odr_reset()</function>.
6818 For this purpose, the memory manager which also supports the &odr;
6819 streams is made available in the NMEM module. The external interface
6820 to this module is given in the <filename>nmem.h</filename> file.
6823 The following prototypes are given:
6826 NMEM nmem_create(void);
6827 void nmem_destroy(NMEM n);
6828 void *nmem_malloc(NMEM n, size_t size);
6829 void nmem_reset(NMEM n);
6830 size_t nmem_total(NMEM n);
6831 void nmem_init(void);
6832 void nmem_exit(void);
6835 The <function>nmem_create()</function> function returns a pointer to a
6836 memory control handle, which can be released again by
6837 <function>nmem_destroy()</function> when no longer needed.
6838 The function <function>nmem_malloc()</function> allocates a block of
6839 memory of the requested size. A call to <function>nmem_reset()</function>
6840 or <function>nmem_destroy()</function> will release all memory allocated
6841 on the handle since it was created (or since the last call to
6842 <function>nmem_reset()</function>. The function
6843 <function>nmem_total()</function> returns the number of bytes currently
6844 allocated on the handle.
6847 The nibble memory pool is shared amongst threads. POSIX
6848 mutex'es and WIN32 Critical sections are introduced to keep the
6849 module thread safe. Function <function>nmem_init()</function>
6850 initializes the nibble memory library and it is called automatically
6851 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
6852 function <function>DllMain</function> to achieve this. You should
6853 <emphasis>not</emphasis> call <function>nmem_init</function> or
6854 <function>nmem_exit</function> unless you're absolute sure what
6855 you're doing. Note that in previous &yaz; versions you'd have to call
6856 <function>nmem_init</function> yourself.
6859 <sect1 id="tools.log">
6862 &yaz; has evolved a fairly complex log system which should be useful both
6863 for debugging &yaz; itself, debugging applications that use &yaz;, and for
6864 production use of those applications.
6867 The log functions are declared in header <filename>yaz/log.h</filename>
6868 and implemented in <filename>src/log.c</filename>.
6869 Due to name clash with syslog and some math utilities the logging
6870 interface has been modified as of YAZ 2.0.29. The obsolete interface
6871 is still available if in header file <filename>yaz/log.h</filename>.
6872 The key points of the interface are:
6875 void yaz_log(int level, const char *fmt, ...)
6876 void yaz_log_init(int level, const char *prefix, const char *name);
6877 void yaz_log_init_file(const char *fname);
6878 void yaz_log_init_level(int level);
6879 void yaz_log_init_prefix(const char *prefix);
6880 void yaz_log_time_format(const char *fmt);
6881 void yaz_log_init_max_size(int mx);
6883 int yaz_log_mask_str(const char *str);
6884 int yaz_log_module_level(const char *name);
6887 The reason for the whole log module is the <function>yaz_log</function>
6888 function. It takes a bitmask indicating the log levels, a
6889 <literal>printf</literal>-like format string, and a variable number of
6893 The <literal>log level</literal> is a bit mask, that says on which level(s)
6894 the log entry should be made, and optionally set some behaviour of the
6895 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
6896 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
6897 that modify the way the log entry is written:<literal>YLOG_ERRNO,
6898 YLOG_NOTIME, YLOG_FLUSH</literal>.
6899 Most of the rest of the bits are deprecated, and should not be used. Use
6900 the dynamic log levels instead.
6903 Applications that use &yaz;, should not use the LOG_LOG for ordinary
6904 messages, but should make use of the dynamic loglevel system. This consists
6905 of two parts, defining the loglevel and checking it.
6908 To define the log levels, the (main) program should pass a string to
6909 <function>yaz_log_mask_str</function> to define which log levels are to be
6910 logged. This string should be a comma-separated list of log level names,
6911 and can contain both hard-coded names and dynamic ones. The log level
6912 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
6913 for each word it meets, unless the word starts with a '-', in which case it
6914 clears the bit. If the string <literal>'none'</literal> is found,
6915 all bits are cleared. Typically this string comes from the command-line,
6916 often identified by <literal>-v</literal>. The
6917 <function>yaz_log_mask_str</function> returns a log level that should be
6918 passed to <function>yaz_log_init_level</function> for it to take effect.
6921 Each module should check what log bits it should be used, by calling
6922 <function>yaz_log_module_level</function> with a suitable name for the
6923 module. The name is cleared from a preceding path and an extension, if any,
6924 so it is quite possible to use <literal>__FILE__</literal> for it. If the
6925 name has been passed to <function>yaz_log_mask_str</function>, the routine
6926 returns a non-zero bitmask, which should then be used in consequent calls
6927 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
6928 yaz_log, in time-critical places, or when the log entry would take time
6932 Yaz uses the following dynamic log levels:
6933 <literal>server, session, request, requestdetail</literal> for the server
6935 <literal>zoom</literal> for the zoom client api.
6936 <literal>ztest</literal> for the simple test server.
6937 <literal>malloc, nmem, odr, eventl</literal> for internal
6938 debugging of yaz itself.
6939 Of course, any program using yaz is welcome to define as many new
6943 By default the log is written to stderr, but this can be changed by a call
6944 to <function>yaz_log_init_file</function> or
6945 <function>yaz_log_init</function>. If the log is directed to a file, the
6946 file size is checked at every write, and if it exceeds the limit given in
6947 <function>yaz_log_init_max_size</function>, the log is rotated. The
6948 rotation keeps one old version (with a <literal>.1</literal> appended to
6949 the name). The size defaults to 1GB. Setting it to zero will disable the
6953 A typical yaz-log looks like this
6954 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
6955 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
6956 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
6957 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
6958 13:24:13-23/11 yaz-ztest(1) [request] Close OK
6961 The log entries start with a time stamp. This can be omitted by setting the
6962 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
6963 can be hoped to produce identical log files, that are easy to diff. The
6964 format of the time stamp can be set with
6965 <function>yaz_log_time_format</function>, which takes a format string just
6966 like <function>strftime</function>.
6969 Next in a log line comes the prefix, often the name of the program. For
6970 yaz-based servers, it can also contain the session number. Then
6971 comes one or more logbits in square brackets, depending on the logging
6972 level set by <function>yaz_log_init_level</function> and the loglevel
6973 passed to <function>yaz_log_init_level</function>. Finally comes the format
6974 string and additional values passed to <function>yaz_log</function>
6977 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
6978 <literal>loglevel</literal>, will log all the log-level affecting
6979 operations. This can come in handy if you need to know what other log
6980 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
6983 The log system is almost independent of the rest of &yaz;, the only
6984 important dependence is of <filename>nmem</filename>, and that only for
6985 using the semaphore definition there.
6988 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
6989 the same time, the log bit names were changed from
6990 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
6991 to avoid collision with <filename>syslog.h</filename>.
6997 YAZ provides a fast utility for working with MARC records.
6998 Early versions of the MARC utility only allowed decoding of ISO2709.
6999 Today the utility may both encode - and decode to a varity of formats.
7002 #include <yaz/marcdisp.h>
7004 /* create handler */
7005 yaz_marc_t yaz_marc_create(void);
7007 void yaz_marc_destroy(yaz_marc_t mt);
7009 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
7010 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
7011 #define YAZ_MARC_LINE 0
7012 #define YAZ_MARC_SIMPLEXML 1
7013 #define YAZ_MARC_OAIMARC 2
7014 #define YAZ_MARC_MARCXML 3
7015 #define YAZ_MARC_ISO2709 4
7016 #define YAZ_MARC_XCHANGE 5
7017 #define YAZ_MARC_CHECK 6
7018 #define YAZ_MARC_TURBOMARC 7
7019 #define YAZ_MARC_JSON 8
7021 /* supply iconv handle for character set conversion .. */
7022 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
7024 /* set debug level, 0=none, 1=more, 2=even more, .. */
7025 void yaz_marc_debug(yaz_marc_t mt, int level);
7027 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7028 On success, result in *result with size *rsize. */
7029 int yaz_marc_decode_buf(yaz_marc_t mt, const char *buf, int bsize,
7030 const char **result, size_t *rsize);
7032 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
7033 On success, result in WRBUF */
7034 int yaz_marc_decode_wrbuf(yaz_marc_t mt, const char *buf,
7035 int bsize, WRBUF wrbuf);
7040 The synopsis is just a basic subset of all functionality. Refer
7041 to the actual header file <filename>marcdisp.h</filename> for
7046 A MARC conversion handle must be created by using
7047 <function>yaz_marc_create</function> and destroyed
7048 by calling <function>yaz_marc_destroy</function>.
7051 All other function operate on a <literal>yaz_marc_t</literal> handle.
7052 The output is specified by a call to <function>yaz_marc_xml</function>.
7053 The <literal>xmlmode</literal> must be one of
7056 <term>YAZ_MARC_LINE</term>
7059 A simple line-by-line format suitable for display but not
7060 recommend for further (machine) processing.
7065 <term>YAZ_MARC_MARCXML</term>
7068 <ulink url="&url.marcxml;">MARCXML</ulink>.
7073 <term>YAZ_MARC_ISO2709</term>
7076 ISO2709 (sometimes just referred to as "MARC").
7081 <term>YAZ_MARC_XCHANGE</term>
7084 <ulink url="&url.marcxchange;">MarcXchange</ulink>.
7089 <term>YAZ_MARC_CHECK</term>
7092 Pseudo format for validation only. Does not generate
7093 any real output except diagnostics.
7098 <term>YAZ_MARC_TURBOMARC</term>
7101 XML format with same semantics as MARCXML but more compact
7102 and geared towards fast processing with XSLT. Refer to
7103 <xref linkend="tools.turbomarc"/> for more information.
7108 <term>YAZ_MARC_JSON</term>
7111 <ulink url="&url.marc_in_json;">MARC-in_JSON</ulink> format.
7118 The actual conversion functions are
7119 <function>yaz_marc_decode_buf</function> and
7120 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
7121 a MARC record. The former function operates on simple buffers, the
7122 stores the resulting record in a WRBUF handle (WRBUF is a simple string
7125 <example id="example.marc.display">
7126 <title>Display of MARC record</title>
7128 The following program snippet illustrates how the MARC API may
7129 be used to convert a MARC record to the line-by-line format:
7130 <programlisting><![CDATA[
7131 void print_marc(const char *marc_buf, int marc_buf_size)
7133 char *result; /* for result buf */
7134 size_t result_len; /* for size of result */
7135 yaz_marc_t mt = yaz_marc_create();
7136 yaz_marc_xml(mt, YAZ_MARC_LINE);
7137 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
7138 &result, &result_len);
7139 fwrite(result, result_len, 1, stdout);
7140 yaz_marc_destroy(mt); /* note that result is now freed... */
7146 <sect2 id="tools.turbomarc">
7147 <title>TurboMARC</title>
7149 TurboMARC is yet another XML encoding of a MARC record. The format
7150 was designed for fast processing with XSLT.
7154 Pazpar2 uses XSLT to convert an XML encoded MARC record to an internal
7155 representation. This conversion mostly check the tag of a MARC field
7156 to determine the basic rules in the conversion. This check is
7157 costly when that is tag is encoded as an attribute in MARCXML.
7158 By having the tag value as the element instead, makes processing
7159 many times faster (at least for Libxslt).
7162 TurboMARC is encoded as follows:
7166 Record elements is part of namespace
7167 "<literal>http://www.indexdata.com/turbomarc</literal>".
7172 A record is enclosed in element <literal>r</literal>.
7177 A collection of records is enclosed in element
7178 <literal>collection</literal>.
7183 The leader is encoded as element <literal>l</literal> with the
7184 leader content as its (text) value.
7189 A control field is encoded as element <literal>c</literal> concatenated
7190 with the tag value of the control field if the tag value
7191 matches the regular expression <literal>[a-zA-Z0-9]*</literal>.
7192 If the tag value do not match the regular expression
7193 <literal>[a-zA-Z0-9]*</literal> the control field is encoded
7194 as element <literal>c</literal> and attribute <literal>code</literal>
7195 will hold the tag value.
7196 This rule ensure that in the rare cases where a tag value might
7197 result in a non-wellformed XML YAZ encode it as a coded attribute
7201 The control field content is the the text value of this element.
7202 Indicators are encoded as attribute names
7203 <literal>i1</literal>, <literal>i2</literal>, etc.. and
7204 corresponding values for each indicator.
7209 A data field is encoded as element <literal>d</literal> concatenated
7210 with the tag value of the data field or using the attribute
7211 <literal>code</literal> as described in the rules for control fields.
7212 The children of the data field element is subfield elements.
7213 Each subfield element is encoded as <literal>s</literal>
7214 concatenated with the sub field code.
7215 The text of the subfield element is the contents of the subfield.
7216 Indicators are encoded as attributes for the data field element similar
7217 to the encoding for control fields.
7224 <sect1 id="tools.retrieval">
7225 <title>Retrieval Facility</title>
7227 YAZ version 2.1.20 or later includes a Retrieval facility tool
7228 which allows a SRU/Z39.50 to describe itself and perform record
7229 conversions. The idea is the following:
7233 An SRU/Z39.50 client sends a retrieval request which includes
7234 a combination of the following parameters: syntax (format),
7235 schema (or element set name).
7240 The retrieval facility is invoked with parameters in a
7241 server/proxy. The retrieval facility matches the parameters a set of
7242 "supported" retrieval types.
7243 If there is no match, the retrieval signals an error
7244 (syntax and / or schema not supported).
7249 For a successful match, the backend is invoked with the same
7250 or altered retrieval parameters (syntax, schema). If
7251 a record is received from the backend, it is converted to the
7252 frontend name / syntax.
7257 The resulting record is sent back the client and tagged with
7258 the frontend syntax / schema.
7264 The Retrieval facility is driven by an XML configuration. The
7265 configuration is neither Z39.50 ZeeRex or SRU ZeeRex. But it
7266 should be easy to generate both of them from the XML configuration.
7267 (unfortunately the two versions
7268 of ZeeRex differ substantially in this regard).
7270 <sect2 id="tools.retrieval.format">
7271 <title>Retrieval XML format</title>
7273 All elements should be covered by namespace
7274 <literal>http://indexdata.com/yaz</literal> .
7275 The root element node must be <literal>retrievalinfo</literal>.
7278 The <literal>retrievalinfo</literal> must include one or
7279 more <literal>retrieval</literal> elements. Each
7280 <literal>retrieval</literal> defines specific combination of
7281 syntax, name and identifier supported by this retrieval service.
7284 The <literal>retrieval</literal> element may include any of the
7285 following attributes:
7287 <varlistentry><term><literal>syntax</literal> (REQUIRED)</term>
7290 Defines the record syntax. Possible values is any
7291 of the names defined in YAZ' OID database or a raw
7296 <varlistentry><term><literal>name</literal> (OPTIONAL)</term>
7299 Defines the name of the retrieval format. This can be
7300 any string. For SRU, the value, is equivalent to schema (short-hand);
7301 for Z39.50 it's equivalent to simple element set name.
7302 For YAZ 3.0.24 and later this name may be specified as a glob
7303 expression with operators
7304 <literal>*</literal> and <literal>?</literal>.
7308 <varlistentry><term><literal>identifier</literal> (OPTIONAL)</term>
7311 Defines the URI schema name of the retrieval format. This can be
7312 any string. For SRU, the value, is equivalent to URI schema.
7313 For Z39.50, there is no equivalent.
7320 The <literal>retrieval</literal> may include one
7321 <literal>backend</literal> element. If a <literal>backend</literal>
7322 element is given, it specifies how the records are retrieved by
7323 some backend and how the records are converted from the backend to
7327 The attributes, <literal>name</literal> and <literal>syntax</literal>
7328 may be specified for the <literal>backend</literal> element. These
7329 semantics of these attributes is equivalent to those for the
7330 <literal>retrieval</literal>. However, these values are passed to
7334 The <literal>backend</literal> element may includes one or more
7335 conversion instructions (as children elements). The supported
7338 <varlistentry><term><literal>marc</literal></term>
7341 The <literal>marc</literal> element specifies a conversion
7342 to - and from ISO2709 encoded MARC and
7343 <ulink url="&url.marcxml;">&acro.marcxml;</ulink>/MarcXchange.
7344 The following attributes may be specified:
7347 <term><literal>inputformat</literal> (REQUIRED)</term>
7350 Format of input. Supported values are
7351 <literal>marc</literal> (for ISO2709), <literal>xml</literal>
7352 (MARCXML/MarcXchange) and <literal>json</literal>
7353 (<ulink url="&url.marc_in_json;">MARC-in_JSON</ulink>).
7358 <term><literal>outputformat</literal> (REQUIRED)</term>
7361 Format of output. Supported values are
7362 <literal>line</literal> (MARC line format);
7363 <literal>marcxml</literal> (for MARCXML),
7364 <literal>marc</literal> (ISO2709),
7365 <literal>marcxhcange</literal> (for MarcXchange),
7366 or <literal>json</literal>
7367 (<ulink url="&url.marc_in_json;">MARC-in_JSON </ulink>).
7372 <term><literal>inputcharset</literal> (OPTIONAL)</term>
7375 Encoding of input. For XML input formats, this need not
7376 be given, but for ISO2709 based inputformats, this should
7377 be set to the encoding used. For MARC21 records, a common
7378 inputcharset value would be <literal>marc-8</literal>.
7383 <term><literal>outputcharset</literal> (OPTIONAL)</term>
7386 Encoding of output. If outputformat is XML based, it is
7387 strongly recommened to use <literal>utf-8</literal>.
7396 <term><literal>select</literal></term>
7399 The <literal>select</literal> selects one or more text nodes
7400 and decodes them as XML.
7401 The following attributes may be specified:
7403 <varlistentry><term><literal>path</literal> (REQUIRED)</term>
7406 X-Path expression for selecting text nodes.
7413 This conversion is available in YAZ 5.8.0 and later.
7418 <term><literal>solrmarc</literal></term>
7421 The <literal>solrmarc</literal> decodes solrmarc records.
7422 It assumes that the input is pure solrmarc text (no escaping)
7423 and will convert all sequences of the form #XX; to a single
7424 character of the hexadecimal value as given by XX. The output,
7425 presumably, is a valid ISO2709 buffer.
7428 This conversion is available in YAZ 5.0.21 and later.
7433 <term><literal>xslt</literal></term>
7436 The <literal>xslt</literal> element specifies a conversion
7437 via &acro.xslt;. The following attributes may be specified:
7439 <varlistentry><term><literal>stylesheet</literal> (REQUIRED)</term>
7453 <sect2 id="tools.retrieval.examples">
7454 <title>Retrieval Facility Examples</title>
7455 <example id="tools.retrieval.marc21">
7456 <title>MARC21 backend</title>
7458 A typical way to use the retrieval facility is to enable XML
7459 for servers that only supports ISO2709 encoded MARC21 records.
7461 <programlisting><![CDATA[
7463 <retrieval syntax="usmarc" name="F"/>
7464 <retrieval syntax="usmarc" name="B"/>
7465 <retrieval syntax="xml" name="marcxml"
7466 identifier="info:srw/schema/1/marcxml-v1.1">
7467 <backend syntax="usmarc" name="F">
7468 <marc inputformat="marc" outputformat="marcxml"
7469 inputcharset="marc-8"/>
7472 <retrieval syntax="xml" name="dc">
7473 <backend syntax="usmarc" name="F">
7474 <marc inputformat="marc" outputformat="marcxml"
7475 inputcharset="marc-8"/>
7476 <xslt stylesheet="MARC21slim2DC.xsl"/>
7483 This means that our frontend supports:
7487 MARC21 F(ull) records.
7492 MARC21 B(rief) records.
7502 Dublin core records.
7508 <example id="tools.retrieval.marcxml">
7509 <title>MARCXML backend</title>
7511 SRW/SRU and Solr backends returns records in XML.
7512 If they return MARCXML or MarcXchange, the retrieval module
7513 can convert those into ISO2709 formats, most commonly USMARC
7515 In this example, the backend returns MARCXML for schema="marcxml".
7517 <programlisting><![CDATA[
7519 <retrieval syntax="usmarc">
7520 <backend syntax="xml" name="marcxml">
7521 <marc inputformat="xml" outputformat="marc"
7522 outputcharset="marc-8"/>
7525 <retrieval syntax="xml" name="marcxml"
7526 identifier="info:srw/schema/1/marcxml-v1.1"/>
7527 <retrieval syntax="xml" name="dc">
7528 <backend syntax="xml" name="marcxml">
7529 <xslt stylesheet="MARC21slim2DC.xsl"/>
7536 This means that our frontend supports:
7540 MARC21 records (any element set name) in MARC-8 encoding.
7545 MARCXML records for element-set=marcxml
7550 Dublin core records for element-set=dc.
7557 <sect2 id="tools.retrieval.api">
7560 It should be easy to use the retrieval systems from applications. Refer
7562 <filename>yaz/retrieval.h</filename> and
7563 <filename>yaz/record_conv.h</filename>.
7567 <sect1 id="sorting">
7568 <title>Sorting</title>
7570 This chapter describes sorting and how it is supported in YAZ.
7571 Sorting applies to a result-set.
7573 <ulink url="http://www.loc.gov/z3950/agency/markup/05.html#3.2.7">
7574 Z39.50 sorting facility
7576 takes one or more input result-sets
7577 and one result-set as output. The most simple case is that
7578 the input-set is the same as the output-set.
7581 Z39.50 sorting has a separate APDU (service) that is, thus, performed
7582 following a search (two phases).
7585 In SRU/Solr, however, the model is different. Here, sorting is specified
7586 during the the search operation. Note, however, that SRU might
7587 perform sort as separate search, by referring to an existing result-set
7588 in the query (result-set reference).
7591 <title>Using the Z39.50 sort service</title>
7593 yaz-client and the ZOOM API supports the Z39.50 sort facility. In any
7594 case the sort sequence or sort critiera is using a string notation.
7595 This notation is a one-line notation suitable for being manually
7596 entered or generated and allows for easy logging (one liner).
7597 For the ZOOM API, the sort is specified in the call to ZOOM_query_sortby
7598 function. For yaz-client the sort is performed and specified using
7599 the sort and sort+ commands. For description of the sort criteria notation
7600 refer to the <link linkend="sortspec">sort command</link> in the
7604 The ZOOM API might choose one of several sort strategies for
7605 sorting. Refer to <xref linkend="zoom-sort-strategy"/>.
7609 <title>Type-7 sort</title>
7611 Type-7 sort is an extension to the Bib-1 based RPN query where the
7612 sort specification is embedded as an Attribute-Plus-Term.
7615 The objectives for introducing Type-7 sorting is that it allows
7616 a client to perform sorting even if it does not implement/support
7617 Z39.50 sort. Virtually all Z39.50 client software supports
7618 RPN queries. It also may improve performance because the sort
7619 critieria is specified along with the search query.
7622 The sort is triggered by the presence of type 7 and the value of type 7
7624 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortKeySpec">
7627 The value for type 7 is 1 for ascending and 2 for descending.
7629 <ulink url="http://www.loc.gov/z3950/agency/asn1.html#SortElement">
7632 only the generic part is handled. If generic sortKey is of type
7633 sortField, then attribute type 1 is present and the value is
7634 sortField (InternationalString). If generic sortKey is of type
7635 sortAttributes, then the attributes in list is used . generic sortKey
7636 of type elementSpec is not supported.
7639 The term in the sorting Attribute-Plus-Term combo should hold
7640 an integer. The value is 0 for primary sorting criteria, 1 for second
7646 <title>Facets</title>
7648 YAZ supports facets for in Solr, SRU 2.0 and Z39.50 protocols.
7651 Like Type-1/RPN, YAZ supports a string notation for specifying
7652 facets. For the API this is performed by
7653 <function>yaz_pqf_parse_facet_list</function>.
7656 For ZOOM C the facets are given by option "facets"
7657 For yaz-client it is used for the facets command.
7660 The grammar of this specification is as follows:
7662 facet-spec ::= facet-list
7664 facet-list ::= facet-list ',' attr-spec | attr-spec
7666 attr-spec ::= attr-spec '@attr' string | '@attr' string
7669 The notation is inspired by PQF. The string following '@attr'
7670 may not include blanks and is of the form
7671 <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>,
7672 where <replaceable>type</replaceable> is an integer and
7673 <replaceable>value</replaceable> is a string or an integer.
7676 The Facets specification is not Bib-1. The following types apply:
7678 <table id="facet.attributes">
7679 <title>Facet attributes</title>
7681 <colspec colwidth="2*" colname="type"></colspec>
7682 <colspec colwidth="9*" colname="description"></colspec>
7686 <entry>Description</entry>
7693 Field-name. This is often a string, eg "Author", "Year", etc.
7699 Sort order. Value should be an integer.
7700 Value 0: count descending (frequency). Value 1: alpha ascending.
7706 Number of terms requested.
7721 <title>The ODR Module</title>
7722 <sect1 id="odr.introduction">
7723 <title>Introduction</title>
7725 &odr; is the BER-encoding/decoding subsystem of &yaz;. Care as been taken
7726 to isolate &odr; from the rest of the package - specifically from the
7727 transport interface. &odr; may be used in any context where basic
7728 ASN.1/BER representations are used.
7731 If you are only interested in writing a Z39.50 implementation based on
7732 the PDUs that are already provided with &yaz;, you only need to concern
7733 yourself with the section on managing ODR streams
7734 (<xref linkend="odr.use"/>). Only if you need to
7735 implement ASN.1 beyond that which has been provided, should you
7736 worry about the second half of the documentation
7737 (<xref linkend="odr.programming"/>).
7738 If you use one of the higher-level interfaces, you can skip this
7742 This is important, so we'll repeat it for emphasis: <emphasis>You do
7743 not need to read <xref linkend="odr.programming"/>
7744 to implement Z39.50 with &yaz;.</emphasis>
7747 If you need a part of the protocol that isn't already in &yaz;, you
7748 should contact the authors before going to work on it yourself: We
7749 might already be working on it. Conversely, if you implement a useful
7750 part of the protocol before us, we'd be happy to include it in a
7754 <sect1 id="odr.use">
7755 <title>Using ODR</title>
7756 <sect2 id="odr.streams">
7757 <title>ODR Streams</title>
7759 Conceptually, the ODR stream is the source of encoded data in the
7760 decoding mode; when encoding, it is the receptacle for the encoded
7761 data. Before you can use an ODR stream it must be allocated. This is
7762 done with the function
7765 ODR odr_createmem(int direction);
7768 The <function>odr_createmem()</function> function takes as argument one
7769 of three manifest constants: <literal>ODR_ENCODE</literal>,
7770 <literal>ODR_DECODE</literal>, or <literal>ODR_PRINT</literal>.
7771 An &odr; stream can be in only one mode - it is not possible to change
7772 its mode once it's selected. Typically, your program will allocate
7773 at least two ODR streams - one for decoding, and one for encoding.
7776 When you're done with the stream, you can use
7779 void odr_destroy(ODR o);
7782 to release the resources allocated for the stream.
7785 <sect2 id="odr.memory.management">
7786 <title id="memory">Memory Management</title>
7788 Two forms of memory management take place in the &odr; system. The first
7789 one, which has to do with allocating little bits of memory (sometimes
7790 quite large bits of memory, actually) when a protocol package is
7791 decoded, and turned into a complex of interlinked structures. This
7792 section deals with this system, and how you can use it for your own
7793 purposes. The next section deals with the memory management which is
7794 required when encoding data - to make sure that a large enough buffer is
7795 available to hold the fully encoded PDU.
7798 The &odr; module has its own memory management system, which is
7799 used whenever memory is required. Specifically, it is used to allocate
7800 space for data when decoding incoming PDUs. You can use the memory
7801 system for your own purposes, by using the function
7804 void *odr_malloc(ODR o, size_t size);
7807 You can't use the normal <function>free(2)</function> routine to free
7808 memory allocated by this function, and &odr; doesn't provide a parallel
7809 function. Instead, you can call
7812 void odr_reset(ODR o);
7815 when you are done with the
7816 memory: Everything allocated since the last call to
7817 <function>odr_reset()</function> is released.
7818 The <function>odr_reset()</function> call is also required to clear
7819 up an error condition on a stream.
7825 size_t odr_total(ODR o);
7828 returns the number of bytes allocated on the stream since the last call to
7829 <function>odr_reset()</function>.
7832 The memory subsystem of &odr; is fairly efficient at allocating and
7833 releasing little bits of memory. Rather than managing the individual,
7834 small bits of space, the system maintains a free-list of larger chunks
7835 of memory, which are handed out in small bits. This scheme is
7836 generally known as a <emphasis>nibble memory</emphasis> system.
7837 It is very useful for maintaining short-lived constructions such
7841 If you want to retain a bit of memory beyond the next call to
7842 <function>odr_reset()</function>, you can use the function
7845 ODR_MEM odr_extract_mem(ODR o);
7848 This function will give you control of the memory recently allocated
7849 on the ODR stream. The memory will live (past calls to
7850 <function>odr_reset()</function>), until you call the function
7853 void odr_release_mem(ODR_MEM p);
7856 The opaque <literal>ODR_MEM</literal> handle has no other purpose than
7857 referencing the memory block for you until you want to release it.
7860 You can use <function>odr_extract_mem()</function> repeatedly between
7861 allocating data, to retain individual control of separate chunks of data.
7864 <sect2 id="odr.encoding.and.decoding">
7865 <title>Encoding and Decoding Data</title>
7867 When encoding data, the ODR stream will write the encoded octet string
7868 in an internal buffer. To retrieve the data, use the function
7871 char *odr_getbuf(ODR o, int *len, int *size);
7874 The integer pointed to by len is set to the length of the encoded
7875 data, and a pointer to that data is returned. <literal>*size</literal>
7876 is set to the size of the buffer (unless <literal>size</literal> is null,
7877 signaling that you are not interested in the size). The next call to
7878 a primitive function using the same &odr; stream will overwrite the
7879 data, unless a different buffer has been supplied using the call
7882 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
7885 which sets the encoding (or decoding) buffer used by
7886 <literal>o</literal> to <literal>buf</literal>, using the length
7887 <literal>len</literal>.
7888 Before a call to an encoding function, you can use
7889 <function>odr_setbuf()</function> to provide the stream with an encoding
7890 buffer of sufficient size (length). The <literal>can_grow</literal>
7891 parameter tells the encoding &odr; stream whether it is allowed to use
7892 <function>realloc(2)</function> to increase the size of the buffer when
7893 necessary. The default condition of a new encoding stream is equivalent
7894 to the results of calling
7897 odr_setbuf(stream, 0, 0, 1);
7900 In this case, the stream will allocate and reallocate memory as
7901 necessary. The stream reallocates memory by repeatedly doubling the
7902 size of the buffer - the result is that the buffer will typically
7903 reach its maximum, working size with only a small number of reallocation
7904 operations. The memory is freed by the stream when the latter is destroyed,
7905 unless it was assigned by the user with the <literal>can_grow</literal>
7906 parameter set to zero (in this case, you are expected to retain
7907 control of the memory yourself).
7910 To assume full control of an encoded buffer, you must first call
7911 <function>odr_getbuf()</function> to fetch the buffer and its length.
7912 Next, you should call <function>odr_setbuf()</function> to provide a
7913 different buffer (or a null pointer) to the stream. In the simplest
7914 case, you will reuse the same buffer over and over again, and you
7915 will just need to call <function>odr_getbuf()</function> after each
7916 encoding operation to get the length and address of the buffer.
7917 Note that the stream may reallocate the buffer during an encoding
7918 operation, so it is necessary to retrieve the correct address after
7919 each encoding operation.
7922 It is important to realize that the ODR stream will not release this
7923 memory when you call <function>odr_reset()</function>: It will
7924 merely update its internal pointers to prepare for the encoding of a
7926 When the stream is released by the <function>odr_destroy()</function>
7927 function, the memory given to it by <function>odr_setbuf</function> will
7928 be released <emphasis>only</emphasis> if the <literal>can_grow</literal>
7929 parameter to <function>odr_setbuf()</function> was nonzero. The
7930 <literal>can_grow</literal> parameter, in other words, is a way of
7931 signaling who is to own the buffer, you or the ODR stream. If you never call
7932 <function>odr_setbuf()</function> on your encoding stream, which is
7933 typically the case, the buffer allocated by the stream will belong to
7934 the stream by default.
7937 When you wish to decode data, you should first call
7938 <function>odr_setbuf()</function>, to tell the decoding stream
7939 where to find the encoded data, and how long the buffer is
7940 (the <literal>can_grow</literal> parameter is ignored by a decoding
7941 stream). After this, you can call the function corresponding to the
7942 data you wish to decode (eg, <function>odr_integer()</function> odr
7943 <function>z_APDU()</function>).
7945 <example id="example.odr.encoding.and.decoding.functions">
7946 <title>Encoding and decoding functions</title>
7948 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
7950 int z_APDU(ODR o, Z_APDU **p, int optional, const char *name);
7954 If the data is absent (or doesn't match the tag corresponding to
7955 the type), the return value will be either 0 or 1 depending on the
7956 <literal>optional</literal> flag. If <literal>optional</literal>
7957 is 0 and the data is absent, an error flag will be raised in the
7958 stream, and you'll need to call <function>odr_reset()</function> before
7959 you can use the stream again. If <literal>optional</literal> is
7960 nonzero, the pointer <emphasis>pointed</emphasis> to/ by
7961 <literal>p</literal> will be set to the null value, and the function
7963 The <literal>name</literal> argument is used to pretty-print the
7964 tag in question. It may be set to <literal>NULL</literal> if
7965 pretty-printing is not desired.
7968 If the data value is found where it's expected, the pointer
7969 <emphasis>pointed to</emphasis> by the <literal>p</literal> argument
7970 will be set to point to the decoded type.
7971 The space for the type will be allocated and owned by the &odr;
7972 stream, and it will live until you call
7973 <function>odr_reset()</function> on the stream. You cannot use
7974 <function>free(2)</function> to release the memory.
7975 You can decode several data elements (by repeated calls to
7976 <function>odr_setbuf()</function> and your decoding function), and
7977 new memory will be allocated each time. When you do call
7978 <function>odr_reset()</function>, everything decoded since the
7979 last call to <function>odr_reset()</function> will be released.
7981 <example id="example.odr.encoding.of.integer">
7982 <title>Encoding and decoding of an integer</title>
7984 The use of the double indirection can be a little confusing at first
7985 (its purpose will become clear later on, hopefully),
7986 so an example is in order. We'll encode an integer value, and
7987 immediately decode it again using a different stream. A useless, but
7988 informative operation.
7990 <programlisting><![CDATA[
7991 void do_nothing_useful(Odr_int value)
7994 Odr_int *valp, *resvalp;
7998 /* allocate streams */
7999 if (!(encode = odr_createmem(ODR_ENCODE)))
8001 if (!(decode = odr_createmem(ODR_DECODE)))
8005 if (odr_integer(encode, &valp, 0, 0) == 0)
8007 printf("encoding went bad\n");
8010 bufferp = odr_getbuf(encode, &len, 0);
8011 printf("length of encoded data is %d\n", len);
8013 /* now let's decode the thing again */
8014 odr_setbuf(decode, bufferp, len, 0);
8015 if (odr_integer(decode, &resvalp, 0, 0) == 0)
8017 printf("decoding went bad\n");
8020 /* ODR_INT_PRINTF format for printf (such as %d) */
8021 printf("the value is " ODR_INT_PRINTF "\n", *resvalp);
8024 odr_destroy(encode);
8025 odr_destroy(decode);
8030 This looks like a lot of work, offhand. In practice, the &odr; streams
8031 will typically be allocated once, in the beginning of your program
8032 (or at the beginning of a new network session), and the encoding
8033 and decoding will only take place in a few, isolated places in your
8034 program, so the overhead is quite manageable.
8038 <sect2 id="odr.printing">
8039 <title>Printing</title>
8041 When an ODR stream is created of type <literal>ODR_PRINT</literal>
8042 the ODR module will print the contents of a PDU in a readable format.
8043 By default output is written to the <literal>stderr</literal> stream.
8044 This behavior can be changed, however, by calling the function
8046 odr_setprint(ODR o, FILE *file);
8048 before encoders or decoders are being invoked.
8049 It is also possible to direct the output to a buffer (of indeed
8050 another file), by using the more generic mechanism:
8052 void odr_set_stream(ODR o, void *handle,
8053 void (*stream_write)(ODR o, void *handle, int type,
8054 const char *buf, int len),
8055 void (*stream_close)(void *handle));
8057 Here the user provides an opaque handle and two handlers,
8058 <replaceable>stream_write</replaceable> for writing,
8059 and <replaceable>stream_close</replaceable> which is supposed
8060 to close/free resources associated with handle.
8061 The <replaceable>stream_close</replaceable> handler is optional and
8062 if NULL for the function is provided, it will not be invoked.
8063 The <replaceable>stream_write</replaceable> takes the ODR handle
8064 as parameter, the user defined handle, a type
8065 <literal>ODR_OCTETSTRING</literal>, <literal>ODR_VISIBLESTRING</literal>
8066 which indicates the type of contents is being written.
8069 Another utility useful for diagnostics (error handling) or as
8070 part of the printing facilities is:
8072 const char **odr_get_element_path(ODR o);
8074 which returns a list of current elements that ODR deals with at the
8075 moment. For the returned array, say <literal>ar</literal>,
8076 <literal>ar[0]</literal> is the top level element,
8077 <literal>ar[n]</literal> is the last. The last element has the
8078 property that <literal>ar[n+1] == NULL</literal>.
8080 <example id="example.odr.element.path.record">
8081 <title>Element Path for record</title>
8083 For a database record part of a PresentResponse the
8084 array returned by <function>odr_get_element</function>
8085 is <literal>presentResponse</literal>, <literal>databaseOrSurDiagnostics</literal>, <literal>?</literal>, <literal>record</literal>, <literal>?</literal>, <literal>databaseRecord</literal> . The question mark appears due to
8086 unnamed constructions.
8090 <sect2 id="odr.diagnostics">
8091 <title>Diagnostics</title>
8093 The encoding/decoding functions all return 0 when an error occurs.
8094 Until you call <function>odr_reset()</function>, you cannot use the
8095 stream again, and any function called will immediately return 0.
8098 To provide information to the programmer or administrator, the function
8101 void odr_perror(ODR o, char *message);
8104 is provided, which prints the <literal>message</literal> argument to
8105 <literal>stderr</literal> along with an error message from the stream.
8108 You can also use the function
8111 int odr_geterror(ODR o);
8114 to get the current error number from the screen. The number will be
8115 one of these constants:
8117 <table frame="top" id="odr.error.codes">
8118 <title>ODR Error codes</title>
8123 <entry>Description</entry>
8128 <entry>OMEMORY</entry><entry>Memory allocation failed.</entry>
8131 <entry>OSYSERR</entry><entry>A system- or library call has failed.
8132 The standard diagnostic variable <literal>errno</literal> should be
8133 examined to determine the actual error.</entry>
8136 <entry>OSPACE</entry><entry>No more space for encoding.
8137 This will only occur when the user has explicitly provided a
8138 buffer for an encoding stream without allowing the system to
8139 allocate more space.</entry>
8142 <entry>OREQUIRED</entry><entry>This is a common protocol error; A
8143 required data element was missing during encoding or decoding.</entry>
8146 <entry>OUNEXPECTED</entry><entry>An unexpected data element was
8147 found during decoding.</entry>
8150 <entry>OOTHER</entry><entry>Other error. This is typically an
8151 indication of misuse of the &odr; system by the programmer, and also
8152 that the diagnostic system isn't as good as it should be, yet.</entry>
8158 The character string array
8164 can be indexed by the error code to obtain a human-readable
8165 representation of the problem.
8168 <sect2 id="odr.summary.and.synopsis">
8169 <title>Summary and Synopsis</title>
8171 #include <yaz/odr.h>
8173 ODR odr_createmem(int direction);
8175 void odr_destroy(ODR o);
8177 void odr_reset(ODR o);
8179 char *odr_getbuf(ODR o, int *len, int *size);
8181 void odr_setbuf(ODR o, char *buf, int len, int can_grow);
8183 void *odr_malloc(ODR o, int size);
8185 NMEM odr_extract_mem(ODR o);
8187 int odr_geterror(ODR o);
8189 void odr_perror(ODR o, const char *message);
8191 extern char *odr_errlist[];
8195 <sect1 id="odr.programming">
8196 <title>Programming with ODR</title>
8198 The API of &odr; is designed to reflect the structure of ASN.1, rather
8199 than BER itself. Future releases may be able to represent data in
8200 other external forms.
8204 There is an ASN.1 tutorial available at
8205 <ulink url="&url.asn.1.tutorial;">this site</ulink>.
8206 This site also has standards for ASN.1 (X.680) and BER (X.690)
8207 <ulink url="&url.asn.1.standards;">online</ulink>.
8211 The ODR interface is based loosely on that of the Sun Microsystems
8213 Specifically, each function which corresponds to an ASN.1 primitive
8214 type has a dual function. Depending on the settings of the ODR
8215 stream which is supplied as a parameter, the function may be used
8216 either to encode or decode data. The functions that can be built
8217 using these primitive functions, to represent more complex data types,
8218 share this quality. The result is that you only have to enter the
8219 definition for a type once - and you have the functionality of encoding,
8220 decoding (and pretty-printing) all in one unit.
8221 The resulting C source code is quite compact, and is a pretty
8222 straightforward representation of the source ASN.1 specification.
8225 In many cases, the model of the XDR functions works quite well in this
8227 In others, it is less elegant. Most of the hassle comes from the optional
8228 SEQUENCE members which don't exist in XDR.
8230 <sect2 id="odr.primitive.asn1.types">
8231 <title>The Primitive ASN.1 Types</title>
8233 ASN.1 defines a number of primitive types (many of which correspond
8234 roughly to primitive types in structured programming languages, such as C).
8236 <sect3 id="odr.integer">
8237 <title>INTEGER</title>
8239 The &odr; function for encoding or decoding (or printing) the ASN.1
8240 INTEGER type looks like this:
8243 int odr_integer(ODR o, Odr_int **p, int optional, const char *name);
8246 The <literal>Odr_int</literal> is just a simple integer.
8249 This form is typical of the primitive &odr; functions. They are named
8250 after the type of data that they encode or decode. They take an &odr;
8251 stream, an indirect reference to the type in question, and an
8252 <literal>optional</literal> flag (corresponding to the OPTIONAL keyword
8253 of ASN.1) as parameters. They all return an integer value of either one
8255 When you use the primitive functions to construct encoders for complex
8256 types of your own, you should follow this model as well. This
8257 ensures that your new types can be reused as elements in yet more
8261 The <literal>o</literal> parameter should obviously refer to a properly
8262 initialized &odr; stream of the right type (encoding/decoding/printing)
8263 for the operation that you wish to perform.
8266 When encoding or printing, the function first looks at
8267 <literal>* p</literal>. If <literal>* p</literal> (the pointer pointed
8268 to by <literal>p</literal>) is a null pointer, this is taken to mean that
8269 the data element is absent. If the <literal>optional</literal> parameter
8270 is nonzero, the function will return one (signifying success) without
8271 any further processing. If the <literal>optional</literal> is zero, an
8272 internal error flag is set in the &odr; stream, and the function will
8273 return 0. No further operations can be carried out on the stream without
8274 a call to the function <function>odr_reset()</function>.
8277 If <literal>*p</literal> is not a null pointer, it is expected to
8278 point to an instance of the data type. The data will be subjected to
8279 the encoding rules, and the result will be placed in the buffer held
8280 by the &odr; stream.
8283 The other ASN.1 primitives have similar functions that operate in
8287 <sect3 id="odr.boolean">
8288 <title>BOOLEAN</title>
8290 int odr_bool(ODR o, Odr_bool **p, int optional, const char *name);
8293 <sect3 id="odr.real">
8299 <sect3 id="odr.null">
8302 int odr_null(ODR o, Odr_null **p, int optional, const char *name);
8305 In this case, the value of **p is not important. If <literal>*p</literal>
8306 is different from the null pointer, the null value is present, otherwise
8310 <sect3 id="odr.octet.string">
8311 <title>OCTET STRING</title>
8313 typedef struct odr_oct
8319 int odr_octetstring(ODR o, Odr_oct **p, int optional,
8323 The <literal>buf</literal> field should point to the character array
8324 that holds the octetstring. The <literal>len</literal> field holds the
8326 The character array need not be null terminated.
8329 To make things a little easier, an alternative is given for string
8330 types that are not expected to contain embedded NULL characters (eg.
8334 int odr_cstring(ODR o, char **p, int optional, const char *name);
8337 Which encoded or decodes between OCTETSTRING representations and
8338 null-terminates C strings.
8341 Functions are provided for the derived string types, eg:
8344 int odr_visiblestring(ODR o, char **p, int optional,
8348 <sect3 id="odr.bit.string">
8349 <title>BIT STRING</title>
8351 int odr_bitstring(ODR o, Odr_bitmask **p, int optional,
8355 The opaque type <literal>Odr_bitmask</literal> is only suitable for
8356 holding relatively brief bit strings, eg. for options fields, etc.
8357 The constant <literal>ODR_BITMASK_SIZE</literal> multiplied by 8
8358 gives the maximum possible number of bits.
8361 A set of macros are provided for manipulating the
8362 <literal>Odr_bitmask</literal> type:
8365 void ODR_MASK_ZERO(Odr_bitmask *b);
8367 void ODR_MASK_SET(Odr_bitmask *b, int bitno);
8369 void ODR_MASK_CLEAR(Odr_bitmask *b, int bitno);
8371 int ODR_MASK_GET(Odr_bitmask *b, int bitno);
8374 The functions are modeled after the manipulation functions that
8375 accompany the <literal>fd_set</literal> type used by the
8376 <function>select(2)</function> call.
8377 <literal>ODR_MASK_ZERO</literal> should always be called first on a
8378 new bitmask, to initialize the bits to zero.
8381 <sect3 id="odr.object.identifier">
8382 <title>OBJECT IDENTIFIER</title>
8384 int odr_oid(ODR o, Odr_oid **p, int optional, const char *name);
8387 The C OID representation is simply an array of integers, terminated by
8388 the value -1 (the <literal>Odr_oid</literal> type is synonymous with
8389 the <literal>short</literal> type).
8390 We suggest that you use the OID database module (see
8391 <xref linkend="tools.oid.database"/>) to handle object identifiers
8392 in your application.
8396 <sect2 id="odr.tagging.primitive.types">
8397 <title>Tagging Primitive Types</title>
8399 The simplest way of tagging a type is to use the
8400 <function>odr_implicit_tag()</function> or
8401 <function>odr_explicit_tag()</function> macros:
8404 int odr_implicit_tag(ODR o, Odr_fun fun, int class, int tag,
8405 int optional, const char *name);
8407 int odr_explicit_tag(ODR o, Odr_fun fun, int class, int tag,
8408 int optional, const char *name);
8411 To create a type derived from the integer type by implicit tagging, you
8415 MyInt ::= [210] IMPLICIT INTEGER
8418 In the &odr; system, this would be written like:
8421 int myInt(ODR o, Odr_int **p, int optional, const char *name)
8423 return odr_implicit_tag(o, odr_integer, p,
8424 ODR_CONTEXT, 210, optional, name);
8428 The function <function>myInt()</function> can then be used like any of
8429 the primitive functions provided by &odr;. Note that the behavior of
8430 <function>odr_explicit_tag()</function>
8431 and <function>odr_implicit_tag()</function> macros
8432 act exactly the same as the functions they are applied to - they
8433 respond to error conditions, etc, in the same manner - they
8434 simply have three extra parameters. The class parameter may
8435 take one of the values: <literal>ODR_CONTEXT</literal>,
8436 <literal>ODR_PRIVATE</literal>, <literal>ODR_UNIVERSAL</literal>, or
8437 <literal>/ODR_APPLICATION</literal>.
8440 <sect2 id="odr.constructed.types">
8441 <title>Constructed Types</title>
8443 Constructed types are created by combining primitive types. The
8444 &odr; system only implements the SEQUENCE and SEQUENCE OF constructions
8445 (although adding the rest of the container types should be simple
8446 enough, if the need arises).
8449 For implementing SEQUENCEs, the functions
8452 int odr_sequence_begin(ODR o, void *p, int size, const char *name);
8453 int odr_sequence_end(ODR o);
8459 The <function>odr_sequence_begin()</function> function should be
8460 called in the beginning of a function that implements a SEQUENCE type.
8461 Its parameters are the &odr; stream, a pointer (to a pointer to the type
8462 you're implementing), and the <literal>size</literal> of the type
8463 (typically a C structure). On encoding, it returns 1 if
8464 <literal>* p</literal> is a null pointer. The <literal>size</literal>
8465 parameter is ignored. On decoding, it returns 1 if the type is found in
8466 the data stream. <literal>size</literal> bytes of memory are allocated,
8467 and <literal>*p</literal> is set to point to this space.
8468 <function>odr_sequence_end()</function> is called at the end of the
8469 complex function. Assume that a type is defined like this:
8472 MySequence ::= SEQUENCE {
8474 boolval BOOLEAN OPTIONAL
8478 The corresponding &odr; encoder/decoder function and the associated data
8479 structures could be written like this:
8482 typedef struct MySequence
8488 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8490 if (odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8491 return optional && odr_ok(o);
8493 odr_integer(o, &(*p)->intval, 0, "intval") &&
8494 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8495 odr_sequence_end(o);
8499 Note the 1 in the call to <function>odr_bool()</function>, to mark
8500 that the sequence member is optional.
8501 If either of the member types had been tagged, the macros
8502 <function>odr_implicit_tag()</function> or
8503 <function>odr_explicit_tag()</function>
8504 could have been used.
8505 The new function can be used exactly like the standard functions provided
8506 with &odr;. It will encode, decode or pretty-print a data value of the
8507 <literal>MySequence</literal> type. We like to name types with an
8508 initial capital, as done in ASN.1 definitions, and to name the
8509 corresponding function with the first character of the name in lower case.
8510 You could, of course, name your structures, types, and functions any way
8511 you please - as long as you're consistent, and your code is easily readable.
8512 <literal>odr_ok</literal> is just that - a predicate that returns the
8513 state of the stream. It is used to ensure that the behavior of the new
8514 type is compatible with the interface of the primitive types.
8517 <sect2 id="odr.tagging.constructed.types">
8518 <title>Tagging Constructed Types</title>
8521 See <xref linkend="odr.tagging.primitive.types"/> for information
8522 on how to tag the primitive types, as well as types that are
8526 <sect3 id="odr.implicit.tagging">
8527 <title>Implicit Tagging</title>
8529 Assume the type above had been defined as
8532 MySequence ::= [10] IMPLICIT SEQUENCE {
8534 boolval BOOLEAN OPTIONAL
8538 You would implement this in &odr; by calling the function
8541 int odr_implicit_settag(ODR o, int class, int tag);
8544 which overrides the tag of the type immediately following it. The
8545 macro <function>odr_implicit_tag()</function> works by calling
8546 <function>odr_implicit_settag()</function> immediately
8547 before calling the function pointer argument.
8548 Your type function could look like this:
8551 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8553 if (odr_implicit_settag(o, ODR_CONTEXT, 10) == 0 ||
8554 odr_sequence_begin(o, p, sizeof(**p), name) == 0)
8555 return optional && odr_ok(o);
8557 odr_integer(o, &(*p)->intval, 0, "intval") &&
8558 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8559 odr_sequence_end(o);
8563 The definition of the structure <literal>MySequence</literal> would be
8567 <sect3 id="odr.explicit.tagging">
8568 <title>Explicit Tagging</title>
8570 Explicit tagging of constructed types is a little more complicated,
8571 since you are in effect adding a level of construction to the data.
8574 Assume the definition:
8577 MySequence ::= [10] IMPLICIT SEQUENCE {
8579 boolval BOOLEAN OPTIONAL
8583 Since the new type has an extra level of construction, two new functions
8584 are needed to encapsulate the base type:
8587 int odr_constructed_begin(ODR o, void *p, int class, int tag,
8590 int odr_constructed_end(ODR o);
8593 Assume that the IMPLICIT in the type definition above were replaced
8594 with EXPLICIT (or that the IMPLICIT keyword were simply deleted, which
8595 would be equivalent). The structure definition would look the same,
8596 but the function would look like this:
8599 int mySequence(ODR o, MySequence **p, int optional, const char *name)
8601 if (odr_constructed_begin(o, p, ODR_CONTEXT, 10, name) == 0)
8602 return optional && odr_ok(o);
8603 if (o->direction == ODR_DECODE)
8604 *p = odr_malloc(o, sizeof(**p));
8605 if (odr_sequence_begin(o, p, sizeof(**p), 0) == 0)
8607 *p = 0; /* this is almost certainly a protocol error */
8611 odr_integer(o, &(*p)->intval, 0, "intval") &&
8612 odr_bool(o, &(*p)->boolval, 1, "boolval") &&
8613 odr_sequence_end(o) &&
8614 odr_constructed_end(o);
8618 Notice that the interface here gets kind of nasty. The reason is
8619 simple: Explicitly tagged, constructed types are fairly rare in
8620 the protocols that we care about, so the
8621 esthetic annoyance (not to mention the dangers of a cluttered
8622 interface) is less than the time that would be required to develop a
8623 better interface. Nevertheless, it is far from satisfying, and it's a
8624 point that will be worked on in the future. One option for you would
8625 be to simply apply the <function>odr_explicit_tag()</function> macro to
8626 the first function, and not
8627 have to worry about <function>odr_constructed_*</function> yourself.
8628 Incidentally, as you might have guessed, the
8629 <function>odr_sequence_</function> functions are themselves
8630 implemented using the <function>/odr_constructed_</function> functions.
8634 <sect2 id="odr.sequence.of">
8635 <title>SEQUENCE OF</title>
8637 To handle sequences (arrays) of a specific type, the function
8640 int odr_sequence_of(ODR o, int (*fun)(ODR o, void *p, int optional),
8641 void *p, int *num, const char *name);
8644 The <literal>fun</literal> parameter is a pointer to the decoder/encoder
8645 function of the type. <literal>p</literal> is a pointer to an array of
8646 pointers to your type. <literal>num</literal> is the number of elements
8653 MyArray ::= SEQUENCE OF INTEGER
8656 The C representation might be
8659 typedef struct MyArray
8666 And the function might look like
8669 int myArray(ODR o, MyArray **p, int optional, const char *name)
8671 if (o->direction == ODR_DECODE)
8672 *p = odr_malloc(o, sizeof(**p));
8673 if (odr_sequence_of(o, odr_integer, &(*p)->elements,
8674 &(*p)->num_elements, name))
8677 return optional && odr_ok(o);
8681 <sect2 id="odr.choice.types">
8682 <title>CHOICE Types</title>
8684 The choice type is used fairly often in some ASN.1 definitions, so
8685 some work has gone into streamlining its interface.
8688 CHOICE types are handled by the function:
8691 int odr_choice(ODR o, Odr_arm arm[], void *p, void *whichp,
8695 The <literal>arm</literal> array is used to describe each of the possible
8696 types that the CHOICE type may assume. Internally in your application,
8697 the CHOICE type is represented as a discriminated union. That is, a
8698 C union accompanied by an integer (or enum) identifying the active
8700 <literal>whichp</literal> is a pointer to the union discriminator.
8701 When encoding, it is examined to determine the current type.
8702 When decoding, it is set to reference the type that was found in
8706 The Odr_arm type is defined thus:
8709 typedef struct odr_arm
8720 The interpretation of the fields are:
8724 <term>tagmode</term>
8725 <listitem><para>Either <literal>ODR_IMPLICIT</literal>,
8726 <literal>ODR_EXPLICIT</literal>, or <literal>ODR_NONE</literal> (-1)
8727 to mark no tagging.</para></listitem>
8731 <listitem><para>The value of the discriminator that corresponds to
8732 this CHOICE element. Typically, it will be a #defined constant, or
8733 an enum member.</para></listitem>
8737 <listitem><para>A pointer to a function that implements the type of
8738 the CHOICE member. It may be either a standard &odr; type or a type
8739 defined by yourself.</para></listitem>
8743 <listitem><para>Name of tag.</para></listitem>
8747 A handy way to prepare the array for use by the
8748 <function>odr_choice()</function> function is to
8749 define it as a static, initialized array in the beginning of your
8750 decoding/encoding function. Assume the type definition:
8753 MyChoice ::= CHOICE {
8755 tagged [99] IMPLICIT INTEGER,
8760 Your C type might look like
8763 typedef struct MyChoice
8780 And your function could look like this:
8783 int myChoice(ODR o, MyChoice **p, int optional, const char *name)
8785 static Odr_arm arm[] =
8787 {-1, -1, -1, MyChoice_untagged, odr_integer, "untagged"},
8788 {ODR_IMPLICIT, ODR_CONTEXT, 99, MyChoice_tagged, odr_integer,
8790 {-1, -1, -1, MyChoice_other, odr_boolean, "other"},
8794 if (o->direction == ODR_DECODE)
8795 *p = odr_malloc(o, sizeof(**p);
8797 return optional && odr_ok(o);
8799 if (odr_choice(o, arm, &(*p)->u, &(*p)->which), name)
8802 return optional && odr_ok(o);
8806 In some cases (say, a non-optional choice which is a member of a
8807 sequence), you can "embed" the union and its discriminator in the
8808 structure belonging to the enclosing type, and you won't need to
8809 fiddle with memory allocation to create a separate structure to
8810 wrap the discriminator and union.
8813 The corresponding function is somewhat nicer in the Sun XDR interface.
8814 Most of the complexity of this interface comes from the possibility of
8815 declaring sequence elements (including CHOICEs) optional.
8818 The ASN.1 specifications naturally requires that each member of a
8819 CHOICE have a distinct tag, so they can be told apart on decoding.
8820 Sometimes it can be useful to define a CHOICE that has multiple types
8821 that share the same tag. You'll need some other mechanism, perhaps
8822 keyed to the context of the CHOICE type. In effect, we would like to
8823 introduce a level of context-sensitiveness to our ASN.1 specification.
8824 When encoding an internal representation, we have no problem, as long
8825 as each CHOICE member has a distinct discriminator value. For
8826 decoding, we need a way to tell the choice function to look for a
8827 specific arm of the table. The function
8830 void odr_choice_bias(ODR o, int what);
8833 provides this functionality. When called, it leaves a notice for the next
8834 call to <function>odr_choice()</function> to be called on the decoding
8835 stream <literal>o</literal> that only the <literal>arm</literal> entry with
8836 a <literal>which</literal> field equal to <literal>what</literal>
8840 The most important application (perhaps the only one, really) is in
8841 the definition of application-specific EXTERNAL encoders/decoders
8842 which will automatically decode an ANY member given the direct or
8847 <sect1 id="odr.debugging">
8848 <title>Debugging</title>
8850 The protocol modules are suffering somewhat from a lack of diagnostic
8851 tools at the moment. Specifically ways to pretty-print PDUs that
8852 aren't recognized by the system. We'll include something to this end
8853 in a not-too-distant release. In the meantime, what we do when we get
8854 packages we don't understand is to compile the ODR module with
8855 <literal>ODR_DEBUG</literal> defined. This causes the module to dump tracing
8856 information as it processes data units. With this output and the
8857 protocol specification (Z39.50), it is generally fairly easy to see
8862 <chapter id="comstack">
8863 <title>The COMSTACK Module</title>
8864 <sect1 id="comstack.synopsis">
8865 <title>Synopsis (blocking mode)</title>
8866 <programlisting><![CDATA[
8869 int size = 0, length_incoming;
8870 char server_address_str[] = "localhost:9999";
8871 void *server_address_ip;
8874 char *protocol_package = "GET / HTTP/1.0\r\n\r\n";
8875 int protocol_package_length = strlen(protocol_package);
8877 stack = cs_create(tcpip_type, 1, PROTO_HTTP);
8879 perror("cs_create"); /* use perror() here since we have no stack yet */
8883 server_address_ip = cs_straddr(stack, server_address_str);
8884 if (!server_address_ip) {
8885 fprintf(stderr, "cs_straddr: address could not be resolved\n");
8889 status = cs_connect(stack, server_address_ip);
8891 fprintf(stderr, "cs_connect: %s\n", cs_strerror(stack));
8895 status = cs_rcvconnect(stack);
8897 fprintf(stderr, "cs_rcvconnect: %s\n", cs_strerror(stack));
8901 status = cs_put(stack, protocol_package, protocol_package_length);
8903 fprintf(stderr, "cs_put: %s\n", cs_strerror(stack));
8907 /* Now get a response */
8908 length_incoming = cs_get(stack, &buf, &size);
8909 if (!length_incoming) {
8910 fprintf(stderr, "Connection closed\n");
8912 } else if (length_incoming < 0) {
8913 fprintf(stderr, "cs_get: %s\n", cs_strerror(stack));
8918 fwrite(buf, length_incoming, 1, stdout);
8929 <sect1 id="comstack.introduction">
8930 <title>Introduction</title>
8933 subsystem provides a transparent interface to different types of transport
8934 stacks for the exchange of BER-encoded data and HTTP packets.
8935 At present, the RFC1729 method (BER over TCP/IP), local UNIX socket and an
8936 experimental SSL stack are supported, but others may be added in time.
8937 The philosophy of the
8938 module is to provide a simple interface by hiding unused options and
8939 facilities of the underlying libraries. This is always done at the risk
8940 of losing generality, and it may prove that the interface will need
8945 There hasn't been interest in the XTImOSI stack for some years.
8946 Therefore, it is no longer supported.
8950 The interface is implemented in such a fashion that only the
8951 sub-layers constructed to the transport methods that you wish to
8952 use in your application are linked in.
8955 You will note that even though simplicity was a goal in the design,
8956 the interface is still orders of magnitudes more complex than the
8957 transport systems found in many other packages. One reason is that
8958 the interface needs to support the somewhat different requirements of
8959 the different lower-layer communications stacks; another important
8960 reason is that the interface seeks to provide a more or less
8961 industrial-strength approach to asynchronous event-handling.
8962 When no function is allowed to block, things get more complex -
8963 particularly on the server side.
8964 We urge you to have a look at the demonstration client and server
8965 provided with the package. They are meant to be easily readable and
8966 instructive, while still being at least moderately useful.
8969 <sect1 id="comstack.common">
8970 <title>Common Functions</title>
8971 <sect2 id="comstack.managing.endpoints">
8972 <title>Managing Endpoints</title>
8974 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
8977 Creates an instance of the protocol stack - a communications endpoint.
8978 The <literal>type</literal> parameter determines the mode
8979 of communication. At present the following values are supported:
8983 <term><literal>tcpip_type</literal></term>
8984 <listitem><para>TCP/IP (BER over TCP/IP or HTTP over TCP/IP)
8988 <term><literal>ssl_type</literal></term>
8989 <listitem><para>Secure Socket Layer (SSL). This COMSTACK
8990 is experimental and is not fully implemented. If
8991 HTTP is used, this effectively is HTTPS.
8995 <term><literal>unix_type</literal></term>
8996 <listitem><para>Unix socket (unix only). Local Transfer via
8997 file socket. See <citerefentry><refentrytitle>unix</refentrytitle>
8998 <manvolnum>7</manvolnum></citerefentry>.
9003 The <function>cs_create</function> function returns a null-pointer
9004 if a system error occurs.
9005 The <literal>blocking</literal> parameter should be one if
9006 you wish the association to operate in blocking mode, zero otherwise.
9007 The <literal>protocol</literal> field should be
9008 <literal>PROTO_Z3950</literal> or <literal>PROTO_HTTP</literal>.
9009 Protocol <literal>PROTO_SR</literal> is no longer supported.
9012 void cs_close(COMSTACK handle);
9015 Closes the connection (as elegantly as the lower layers will permit),
9016 and releases the resources pointed to by the
9017 <literal>handle</literal>
9019 <literal>handle</literal>
9020 should not be referenced again after this call.
9024 We really need a soft disconnect, don't we?
9028 <sect2 id="comstack.data.exchange">
9029 <title>Data Exchange</title>
9031 int cs_put(COMSTACK handle, char *buf, int len);
9034 Sends <literal>buf</literal> down the wire.
9035 In blocking mode, this function will return only when a full buffer has
9036 been written, or an error has occurred. In nonblocking mode, it's
9037 possible that the function will be unable to send the full buffer
9038 at once, which will be indicated by a return value of 1.
9039 The function will keep track of the number of octets already written; you
9040 should call it repeatedly with the same values of <literal>buf</literal>
9041 and <literal>len</literal>, until the buffer has been transmitted.
9042 When a full buffer has been sent, the function will return 0 for
9043 success. -1 indicates an error condition (see below).
9046 int cs_get(COMSTACK handle, char **buf, int *size);
9049 Receives a PDU or HTTP Response from the peer. Returns the number of
9051 In nonblocking mode, it is possible that not all of the packet can be
9052 read at once. In this case, the function returns 1. To simplify the
9053 interface, the function is
9054 responsible for managing the size of the buffer. It will be reallocated
9055 if necessary to contain large packages, and will sometimes be moved
9056 around internally by the subsystem when partial packages are read. Before
9058 <function>cs_get</function>
9059 for the fist time, the buffer can be initialized to the null pointer,
9060 and the length should also be set to 0 - cs_get will perform a
9061 <function>malloc(2)</function>
9062 on the buffer for you. When a full buffer has been read, the size of
9063 the package is returned (which will always be greater than 1). -1
9064 indicates an error condition.
9067 See also the <function>cs_more()</function> function below.
9070 int cs_more(COMSTACK handle);
9073 The <function>cs_more()</function> function should be used in conjunction
9074 with <function>cs_get</function> and
9075 <function>select(2)</function>.
9076 The <function>cs_get()</function> function will sometimes
9077 (notably in the TCP/IP mode) read more than a single protocol package
9078 off the network. When this happens, the extra package is stored
9079 by the subsystem. After calling <function>cs_get()</function>, and before
9080 waiting for more input, You should always call
9081 <function>cs_more()</function>
9082 to check if there's a full protocol package already read. If
9083 <function>cs_more()</function>
9085 <function>cs_get()</function>
9086 can be used to immediately fetch the new package. For the
9088 subsystem, the function should always return 0, but if you want your
9089 stuff to be protocol independent, you should use it.
9093 The <function>cs_more()</function>
9094 function is required because the RFC1729-method
9095 does not provide a way of separating individual PDUs, short of
9096 partially decoding the BER. Some other implementations will carefully
9097 nibble at the packet by calling
9098 <function>read(2)</function>
9099 several times. This was felt to be too inefficient (or at least
9100 clumsy) - hence the call for this extra function.
9104 int cs_look(COMSTACK handle);
9107 This function is useful when you're operating in nonblocking
9109 <function>select(2)</function>
9110 tells you there's something happening on the line. It returns one of
9111 the following values:
9115 <term>CS_NONE</term>
9117 No event is pending. The data found on the line was not a
9122 <term>CS_CONNECT</term>
9124 A response to your connect request has been received. Call
9125 <function>cs_rcvconnect</function>
9126 to process the event and to finalize the connection establishment.
9130 <term>CS_DISCON</term>
9132 The other side has closed the connection (or maybe sent a disconnect
9133 request - but do we care? Maybe later). Call
9134 <function>cs_close</function> to close your end of the association
9139 <term>CS_LISTEN</term>
9141 A connect request has been received.
9142 Call <function>cs_listen</function> to process the event.
9146 <term>CS_DATA</term>
9148 There's data to be found on the line.
9149 Call <function>cs_get</function> to get it.
9155 You should be aware that even if
9156 <function>cs_look()</function>
9157 tells you that there's an event event pending, the corresponding
9158 function may still return and tell you there was nothing to be found.
9159 This means that only part of a package was available for reading. The
9160 same event will show up again, when more data has arrived.
9164 int cs_fileno(COMSTACK h);
9167 Returns the file descriptor of the association. Use this when
9168 file-level operations on the endpoint are required
9169 (<function>select(2)</function> operations, specifically).
9173 <sect1 id="comstack.client">
9174 <title>Client Side</title>
9176 int cs_connect(COMSTACK handle, void *address);
9179 Initiate a connection with the target at <literal>address</literal>
9180 (more on addresses below). The function will return 0 on success, and 1 if
9181 the operation does not complete immediately (this will only
9182 happen on a nonblocking endpoint). In this case, use
9183 <function>cs_rcvconnect</function> to complete the operation,
9184 when <function>select(2)</function> or <function>poll(2)</function>
9185 reports input pending on the association.
9188 int cs_rcvconnect(COMSTACK handle);
9191 Complete a connect operation initiated by <function>cs_connect()</function>.
9192 It will return 0 on success; 1 if the operation has not yet completed (in
9193 this case, call the function again later); -1 if an error has occurred.
9196 <sect1 id="comstack.server">
9197 <title>Server Side</title>
9199 To establish a server under the <application>inetd</application>
9203 COMSTACK cs_createbysocket(int socket, CS_TYPE type, int blocking,
9207 The <literal>socket</literal> parameter is an established socket (when
9208 your application is invoked from <application>inetd</application>, the
9209 socket will typically be 0.
9210 The following parameters are identical to the ones for
9211 <function>cs_create</function>.
9214 int cs_bind(COMSTACK handle, void *address, int mode)
9217 Binds a local address to the endpoint. Read about addresses below. The
9218 <literal>mode</literal> parameter should be either
9219 <literal>CS_CLIENT</literal> or <literal>CS_SERVER</literal>.
9222 int cs_listen(COMSTACK handle, char *addr, int *addrlen);
9225 Call this to process incoming events on an endpoint that has been
9226 bound in listening mode. It will return 0 to indicate that the connect
9227 request has been received, 1 to signal a partial reception, and -1 to
9228 indicate an error condition.
9231 COMSTACK cs_accept(COMSTACK handle);
9234 This finalizes the server-side association establishment, after
9235 cs_listen has completed successfully. It returns a new connection
9236 endpoint, which represents the new association. The application will
9237 typically wish to fork off a process to handle the association at this
9238 point, and continue listen for new connections on the old
9239 <literal>handle</literal>.
9242 You can use the call
9245 const char *cs_addrstr(COMSTACK);
9248 on an established connection to retrieve the host-name of the remote host.
9252 You may need to use this function with some care if your
9253 name server service is slow or unreliable
9257 <sect1 id="comstack.addresses">
9258 <title>Addresses</title>
9260 The low-level format of the addresses are different depending on the
9261 mode of communication you have chosen. A function is provided by each
9262 of the lower layers to map a user-friendly string-form address to the
9263 binary form required by the lower layers.
9266 void *cs_straddr(COMSTACK handle, const char *str);
9269 The format for TCP/IP and SSL addresses is:
9272 <host> [ ':' <portnum> ]
9275 The <literal>hostname</literal> can be either a domain name or an
9276 IP address. The port number, if omitted, defaults to 210.
9279 For TCP/IP and SSL, the special hostnames <literal>@</literal>,
9280 maps to <literal>IN6ADDR_ANY_INIT</literal> with
9281 IPV4 binding as well (bindv6only=0),
9282 The special hostname <literal>@4</literal> binds to
9283 <literal>INADDR_ANY</literal> (IPV4 only listener).
9284 The special hostname <literal>@6</literal> binds to
9285 <literal>IN6ADDR_ANY_INIT</literal> with bindv6only=1 (IPV6 only listener).
9288 For UNIX sockets, the format of an address is the socket filename.
9291 When a connection has been established, you can use
9294 const char *cs_addrstr(COMSTACK h);
9297 to retrieve the host name of the peer system. The function returns
9298 a pointer to a static area, which is overwritten on the next call
9302 A fairly recent addition to the &comstack; module is the utility
9306 COMSTACK cs_create_host (const char *str, int blocking, void **vp);
9309 which is just a wrapper for <function>cs_create</function> and
9310 <function>cs_straddr</function>. The <parameter>str</parameter>
9311 is similar to that described for <function>cs_straddr</function>
9312 but with a prefix denoting the &comstack; type. Prefixes supported
9313 are <literal>tcp:</literal>, <literal>unix:</literal> and
9314 <literal>ssl:</literal> for TCP/IP, UNIX and SSL respectively.
9315 If no prefix is given, then TCP/IP is used.
9316 The <parameter>blocking</parameter> is passed to
9317 function <function>cs_create</function>. The third parameter
9318 <parameter>vp</parameter> is a pointer to &comstack; stack type
9320 Parameter <parameter>vp</parameter> is reserved for future use.
9321 Set it to <literal>NULL</literal>.
9324 <sect1 id="comstack.ssl">
9328 void *cs_get_ssl(COMSTACK cs);
9330 Returns the SSL handle, <literal>SSL *</literal> for comstack. If comstack
9331 is not of type SSL, NULL is returned.
9335 int cs_set_ssl_ctx(COMSTACK cs, void *ctx);
9337 Sets SSL context for comstack. The parameter is expected to be of type
9338 <literal>SSL_CTX *</literal>. This function should be called just
9339 after comstack has been created (before connect, bind, etc).
9340 This function returns 1 for success; 0 for failure.
9344 int cs_set_ssl_certificate_file(COMSTACK cs, const char *fname);
9346 Sets SSL certificate for comstack as a PEM file. This function
9347 returns 1 for success; 0 for failure.
9351 int cs_get_ssl_peer_certificate_x509(COMSTACK cs, char **buf, int *len);
9353 This function returns the peer certificate. If successful,
9354 <literal>*buf</literal> and <literal>*len</literal> holds
9355 X509 buffer and length respectively. Buffer should be freed
9356 with <literal>xfree</literal>. This function returns 1 for success;
9360 <sect1 id="comstack.diagnostics">
9361 <title>Diagnostics</title>
9363 All functions return -1 if an error occurs. Typically, the functions
9364 will return 0 on success, but the data exchange functions
9365 (<function>cs_get</function>, <function>cs_put</function>,
9366 <function>cs_more</function>) follow special rules. Consult their
9370 The error code for the COMSTACK can be retrieved using C macro
9371 <function>cs_errno</function> which will return one
9372 of the error codes <literal>CSYSERR</literal>,
9373 <literal>CSOUTSTATE</literal>,
9374 <literal>CSNODATA</literal>, ...
9377 int cs_errno(COMSTACK handle);
9380 You can the textual representation of the error code
9381 by using <function>cs_errmsg</function> - which
9382 works like <function>strerror(3)</function>
9385 const char *cs_errmsg(int n);
9388 It is also possible to get straight to the textual represenataion
9389 without the error code by using
9390 <function>cs_strerror</function>.
9393 const char *cs_strerror(COMSTACK h);
9396 <sect1 id="comstack.summary">
9397 <title>Summary and Synopsis</title>
9399 #include <yaz/comstack.h>
9401 #include <yaz/tcpip.h> /* this is for TCP/IP and SSL support */
9402 #include <yaz/unix.h> /* this is for UNIX socket support */
9404 COMSTACK cs_create(CS_TYPE type, int blocking, int protocol);
9406 COMSTACK cs_createbysocket(int s, CS_TYPE type, int blocking,
9408 COMSTACK cs_create_host(const char *str, int blocking,
9411 int cs_bind(COMSTACK handle, int mode);
9413 int cs_connect(COMSTACK handle, void *address);
9415 int cs_rcvconnect(COMSTACK handle);
9417 int cs_listen(COMSTACK handle);
9419 COMSTACK cs_accept(COMSTACK handle);
9421 int cs_put(COMSTACK handle, char *buf, int len);
9423 int cs_get(COMSTACK handle, char **buf, int *size);
9425 int cs_more(COMSTACK handle);
9427 void cs_close(COMSTACK handle);
9429 int cs_look(COMSTACK handle);
9431 void *cs_straddr(COMSTACK handle, const char *str);
9433 const char *cs_addrstr(COMSTACK h);
9438 <chapter id="future">
9439 <title>Future Directions</title>
9441 We have a new and better version of the front-end server on the drawing
9442 board. Resources and external commitments will govern when we'll be
9443 able to do something real with it. Features should include greater
9444 flexibility, greater support for access/resource control, and easy
9445 support for Explain (possibly with Zebra as an extra database engine).
9448 &yaz; is a BER toolkit and as such should support all protocols
9449 out there based on that. We'd like to see running ILL applications.
9450 It shouldn't be that hard. Another thing that would be interesting is
9451 LDAP. Maybe a generic framework for doing IR using both LDAP and
9452 Z39.50 transparently.
9455 The SOAP implementation is incomplete. In the future we hope
9456 to add more features to it. Perhaps make a WSDL/XML Schema compiler.
9457 The authors of libxml2 are already working on XML Schema / RelaxNG
9458 compilers so this may not be too hard.
9461 It would be neat to have a proper module mechanism for the Generic
9462 Frontend Server so that backend would be dynamically
9463 loaded (as shared objects / DLLs).
9466 Other than that, &yaz; generally moves in the directions which appear to
9467 make the most people happy (including ourselves, as prime users of the
9468 software). If there's something you'd like to see in here, then drop
9469 us a note and let's see what we can come up with.
9472 <reference id="reference">
9473 <title>Reference</title>
9474 <partintro id="reference-introduction">
9476 The material in this chapter is drawn directly from the individual
9482 <appendix id="list-oids">
9483 <title>List of Object Identifiers</title>
9485 These is a list of object identifiers that are built into YAZ.
9489 <appendix id="bib1-diagnostics">
9490 <title>Bib-1 diagnostics</title>
9492 List of Bib-1 diagnostics that are known to YAZ.
9496 <appendix id="sru-diagnostics">
9497 <title>SRU diagnostics</title>
9499 List of SRU diagnostics that are known to YAZ.
9503 <appendix id="license">
9504 <title>License</title>
9505 <sect1 id="license.indexdata">
9506 <title>Index Data Copyright</title>
9508 Copyright © ©right-year; Index Data.
9511 All rights reserved.
9514 Redistribution and use in source and binary forms, with or without
9515 modification, are permitted provided that the following conditions are met:
9520 Redistributions of source code must retain the above copyright
9521 notice, this list of conditions and the following disclaimer.
9526 Redistributions in binary form must reproduce the above copyright
9527 notice, this list of conditions and the following disclaimer in the
9528 documentation and/or other materials provided with the distribution.
9533 Neither the name of Index Data nor the names of its contributors
9534 may be used to endorse or promote products derived from this
9535 software without specific prior written permission.
9540 THIS SOFTWARE IS PROVIDED BY INDEX DATA ``AS IS'' AND ANY
9541 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9542 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
9543 DISCLAIMED. IN NO EVENT SHALL INDEX DATA BE LIABLE FOR
9544 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
9545 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
9546 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
9547 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
9548 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
9549 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
9554 <appendix id="indexdata">
9555 <title>About Index Data</title>
9557 Index Data is a consulting and software-development enterprise that
9558 specializes in library and information management systems. Our
9559 interests and expertise span a broad range of related fields, and one
9560 of our primary, long-term objectives is the development of a powerful
9561 information management
9562 system with open network interfaces and hyper-media capabilities.
9564 We make this software available free of charge, on a fairly unrestrictive
9565 license; as a service to the networking community, and to further the
9566 development of quality software for open network communication.
9568 We'll be happy to answer questions about the software, and about ourselves
9574 <street>Amagerfælledvej 56</street>
9575 <postcode>2300 Copenhagen S</postcode>
9576 <country>Denmark</country>
9577 Email <email>info@indexdata.dk</email>
9581 The Hacker's Jargon File has the following to say about the
9583 prefix "YA" in the name of a software product.
9587 Yet Another. adj. 1. Of your own work: A
9588 humorous allusion often used in titles to acknowledge that the
9589 topic is not original, though the content is. As in "Yet Another
9590 AI Group" or "Yet Another Simulated Annealing Algorithm".
9592 others' work: Describes something of which there are already far
9597 <appendix id="credits">
9598 <title>Credits</title>
9600 This appendix lists individuals that have contributed in the development
9601 of &yaz;. Some have contributed with code, while others have provided bug
9602 fixes or suggestions. If we're missing somebody, of if you, for
9603 whatever reason, don't like to be listed here, let us know.
9613 Morten Bøgeskov
9634 Mads Bondo Dydensborg
9643 Morten Garkier Hendriksen
9700 Tom André Øverland
9706 <!-- Keep this comment at the end of the file
9709 nxml-child-indent: 1