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15 <title>Pazpar2 - User's Guide and Reference</title>
17 <firstname>Sebastian</firstname><surname>Hammer</surname>
20 <firstname>Adam</firstname><surname>Dickmeiss</surname>
23 <firstname>Marc</firstname><surname>Cromme</surname>
25 <releaseinfo>&version;</releaseinfo>
27 <year>©right-year;</year>
28 <holder>Index Data</holder>
32 Pazpar2 is a high-performance, user interface-independent, data
33 model-independent metasearching
34 middleware featuring merging, relevance ranking, record sorting,
38 This document is a guide and reference to Pazpar version &version;.
43 <imagedata fileref="common/id.png" format="PNG"/>
46 <imagedata fileref="common/id.eps" format="EPS"/>
53 <chapter id="introduction">
54 <title>Introduction</title>
56 Pazpar2 is a stand-alone metasearch client with a webservice API, designed
57 to be used either from a browser-based client (JavaScript, Flash, Java,
58 etc.), from from server-side code, or any combination of the two.
59 Pazpar2 is a highly optimized client designed to
60 search many resources in parallel. It implements record merging,
61 relevance-ranking and sorting by arbitrary data content, and facet
62 analysis for browsing purposes. It is designed to be data model
63 independent, and is capable of working with MARC, DublinCore, or any
64 other <ulink url="&url.xml;">XML</ulink>-structured response format
65 -- <ulink url="&url.xslt;">XSLT</ulink> is used to normalize and extract
66 data from retrieval records for display and analysis. It can be used
67 against any server which supports the
68 <ulink url="&url.z39.50;">Z39.50</ulink> protocol. Proprietary
69 backend modules can be used to support a large number of other protocols
70 (please contact Index Data for further information about this).
73 Additional functionality such as
74 user management, attractive displays are expected to be implemented by
75 applications that use pazpar2. Pazpar2 is user interface independent.
76 Its functionality is exposed through a simple REST-style webservice API,
77 designed to be simple to use from an Ajax-enbled browser, Flash
78 animation, Java applet, etc., or from a higher-level server-side language
79 like PHP or Java. Because session information can be shared between
80 browser-based logic and your server-side scripting, there is tremendous
81 flexibility in how you implement your business logic on top of pazpar2.
84 Once you launch a search in pazpar2, the operation continues behind the
85 scenes. Pazpar2 connects to servers, carries out searches, and
86 retrieves, deduplicates, and stores results internally. Your application
87 code may periodically inquire about the status of an ongoing operation,
88 and ask to see records or other result set facets. Result become
89 available immediately, and it is easy to build end-user interfaces which
90 feel extremely responsive, even when searching more than 100 servers
94 Pazpar2 is designed to be highly configurable. Incoming records are
95 normalized to XML/UTF-8, and then further normalized using XSLT to a
96 simple internal representation that is suitable for analysis. By
97 providing XSLT stylesheets for different kinds of result records, you
98 can tune pazpar2 to work against different kinds of information
99 retrieval servers. Finally, metadata is extracted, in a configurable
100 way, from this internal record, to support display, merging, ranking,
101 result set facets, and sorting. Pazpar2 is not bound to a specific model
102 of metadata, such as DublinCore or MARC -- by providing the right
103 configuration, it can work with a number of different kinds of data in
104 support of many different applications.
107 Pazpar2 is designed to be efficient and scalable. You can set it up to
108 search several hundred targets in parallel, or you can use it to support
109 hundreds of concurrent users. It is implemented with the same attention
110 to performance and economy that we use in our indexing engines, so that
111 you can focus on building your application, without worrying about the
112 details of metasearch logic. You can devote all of your attention to
113 usability and let pazpar2 do what it does best -- metasearch.
116 If you wish to connect to commercial or other databases which do not
117 support open standards, please contact Index Data. We have a licensing
118 agreement with a third party vendor which will enable pazpar2 to access
119 thousands of online databases, in addition the vast number of catalogs
120 and online services that support the Z39.50 protocol.
123 Pazpar2 is our attempt to re-think the traditional paradigms for
124 implementing and deploying metasearch logic, with an uncompromising
125 approach to performance, and attempting to make maximum use of the
126 capabilities of modern browsers. The demo user interface that
127 accompanies the distribution is but one example. If you think of new
128 ways of using pazpar2, we hope you'll share them with us, and if we
129 can provide assistance with regards to training, design, programming,
130 integration with different backends, hosting, or support, please don't
131 hesitate to contact us. If you'd like to see functionality in pazpar2
132 that is not there today, please don't hesitate to contact us. It may
133 already be in our development pipeline, or there might be a
134 possibility for you to help out by sponsoring development time or
135 code. Either way, get in touch and we will give you straight answers.
141 Pazpar2 is covered by the GNU license version 2.
142 See <xref linkend="license"/> for further information.
146 <chapter id="installation">
147 <title>Installation</title>
149 Pazpar2 depends on the following tools/libraries:
151 <varlistentry><term><ulink url="&url.yaz;">YAZ</ulink></term>
154 The popular Z39.50 toolkit for the C language. YAZ must be
155 compiled with Libxml2/Libxslt support.
159 <varlistentry><term><ulink url="&url.icu;">International
160 Components for Unicode (ICU)</ulink></term>
163 ICU provides Unicode support for non-english languages with
164 character sets outside the range of 7bit ASCII, like
165 Greek, Russian, German and Frensh. Pazpar2 uses the ICU
166 unicode character conversions, unicode normalization, case
167 folding and other fundamental operations needed in
168 tokenization, normalization and ranking of records.
171 Compiling, linking, and usage of the ICU libraries is optional,
172 but strongly recommended for usage in an international
180 In order to compile Pazpar2 an ANSI C compiler is
181 required. The requirements should be the same as for YAZ.
184 <section id="installation.unix">
185 <title>Installation on Unix (from Source)</title>
187 The latest source code for pazpar2 is available from
188 <ulink url="&url.pazpar2.download;"/>.
189 Only few systems have none of the required
190 tools binary packages. If, for example, Libxml2/libxslt are already
191 installed as development packages use these.
195 Ensure that the development libraries + header files are
196 available on your system before compiling Pazpar2. For installation
197 of YAZ, refer to the YAZ installation chapter.
200 gunzip -c pazpar2-version.tar.gz|tar xf -
209 <section id="installation.debian">
210 <title>Installation on Debian GNU/Linux</title>
212 Index Data provides Debian packages for pazpar2. These are prepared
213 for Debian versions Etch and Lenny (as of 2007).
214 Theses packages are available at
215 <ulink url="&url.pazpar2.download.debian;"/>.
219 <section id="installation.apache2proxy">
220 <title>Apache 2 Proxy</title>
223 <ulink url="http://httpd.apache.org/docs/2.2/mod/mod_proxy.html">
225 </ulink> which allows Pazpar2 to become a backend to an Apache 2
226 based web service. The Apache 2 proxy must operate in the
227 <emphasis>Reverse</emphasis> Proxy mode.
231 On a Debian based Apache 2 system, the relevant modules can
234 sudo a2enmod proxy_http
239 Traditionnally Pazpar2 interprets URL paths with suffix
240 <literal>/search.pz2</literal>.
243 url="http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#proxypass"
244 >ProxyPass</ulink> directive of Apache must be used to map a URL path
245 the the Pazpar2 server (listening port).
250 The ProxyPass directive takes a prefix rather than
251 a suffix as URL path. It is important that the Java Script code
252 uses the prefix given for it.
256 <example id="installation.apache2proxy.example">
257 <title>Apache 2 proxy configuration</title>
259 If Pazpar2 is running on port 8004 and the portal is using
260 <filename>search.pz2</filename> inside portal in directory
261 <filename>/myportal/</filename> we could use the following
262 Apache 2 configuration:
265 <IfModule mod_proxy.c>
269 AddDefaultCharset off
274 ProxyPass /myportal/search.pz2 http://localhost:8004/search.pz2
285 <title>Using pazpar2</title>
287 This chapter provides a general introduction to the use and
288 deployment of pazpar2.
291 <section id="architecture">
292 <title>Pazpar2 and your systems architecture</title>
294 Pazpar2 is designed to provide asynchronous, behind-the-scenes
295 metasearching functionality to your application, exposing this
296 functionality using a simple webservice API that can be accessed
297 from any number of development environments. In particular, it is
298 possible to combine pazpar2 either with your server-side dynamic
299 website scripting, with scripting or code running in the browser, or
300 with any combination of the two. Pazpar2 is an excellent tool for
301 building advanced, Ajax-based user interfaces for metasearch
302 functionality, but it isn't a requirement -- you can choose to use
303 pazpar2 entirely as a backend to your regular server-side scripting.
304 When you do use pazpar2 in conjunction
305 with browser scripting (JavaScript/Ajax, Flash, applets,
306 etc.), there are special considerations.
310 Pazpar2 implements a simple but efficient HTTP server, and it is
311 designed to interact directly with scripting running in the browser
312 for the best possible performance, and to limit overhead when
313 several browser clients generate numerous webservice requests.
314 However, it is still desirable to use a conventional webserver,
315 such as Apache, to serve up graphics, HTML documents, and
316 server-side scripting. Because the security sandbox environment of
317 most browser-side programming environments only allows communication
318 with the server from which the enclosing HTML page or object
319 originated, pazpar2 is designed so that it can act as a transparent
320 proxy in front of an existing webserver (see <xref
321 linkend="pazpar2_conf"/> for details).
322 In this mode, all regular
323 HTTP requests are transparently passed through to your webserver,
324 while pazpar2 only intercepts search-related webservice requests.
328 If you want to expose your combined service on port 80, you can
329 either run your regular webserver on a different port, a different
330 server, or a different IP address associated with the same server.
334 pazpar2 can also work behind
335 a reverse Proxy. Refer to <xref linkend="installation.apache2proxy"/>)
336 for more information.
337 This allows your existing HTTP server to operate on port 80 as usual.
338 Pazpar2 can be started on another (internal) port.
342 Sometimes, it may be necessary to implement functionality on your
343 regular webserver that makes use of search results, for example to
344 implement data import functionality, emailing results, history
345 lists, personal citation lists, interlibrary loan functionality
346 ,etc. Fortunately, it is simple to exchange information between
347 pazpar2, your browser scripting, and backend server-side scripting.
348 You can send a session ID and possibly a record ID from your browser
349 code to your server code, and from there use pazpar2s webservice API
350 to access result sets or individual records. You could even 'hide'
351 all of pazpar2s functionality between your own API implemented on
352 the server-side, and access that from the browser or elsewhere. The
353 possibilities are just about endless.
357 <section id="data_model">
358 <title>Your data model</title>
360 Pazpar2 does not have a preconceived model of what makes up a data
361 model. There are no assumption that records have specific fields or
362 that they are organized in any particular way. The only assumption
363 is that data comes packaged in a form that the software can work
364 with (presently, that means XML or MARC), and that you can provide
365 the necessary information to massage it into pazpar2's internal
370 Handling retrieval records in pazpar2 is a two-step process. First,
371 you decide which data elements of the source record you are
372 interested in, and you specify any desired massaging or combining of
373 elements using an XSLT stylesheet (MARC records are automatically
374 normalized to MARCXML before this step). If desired, you can run
375 multiple XSLT stylesheets in series to accomplish this, but the
376 output of the last one should be a representation of the record in a
377 schema that pazpar2 understands.
381 The intermediate, internal representation of the record looks like
384 <record xmlns="http://www.indexdata.com/pazpar2/1.0"
385 mergekey="title The Shining author King, Stephen">
387 <metadata type="title">The Shining</metadata>
389 <metadata type="author">King, Stephen</metadata>
391 <metadata type="kind">ebook</metadata>
393 <!-- ... and so on -->
397 As you can see, there isn't much to it. There are really only a few
398 important elements to this file.
402 Elements should belong to the namespace
403 <literal>http://www.indexdata.com/pazpar2/1.0</literal>.
404 If the root node contains the
405 attribute 'mergekey', then every record that generates the same
406 merge key (normalized for case differences, white space, and
407 truncation) will be joined into a cluster. In other words, you
408 decide how records are merged. If you don't include a merge key,
409 records are never merged. The 'metadata' elements provide the meat
410 of the elements -- the content. the 'type' attribute is used to
411 match each element against processing rules that determine what
412 happens to the data element next.
416 The next processing step is the extraction of metadata from the
417 intermediate representation of the record. This is governed by the
418 'metadata' elements in the 'service' section of the configuration
419 file. See <xref linkend="config-server"/> for details. The metadata
420 in the retrieval record ultimately drives merging, sorting, ranking,
421 the extraction of browse facets, and display, all configurable.
425 <section id="client">
426 <title>Client development overview</title>
428 You can use pazpar2 from any environment that allows you to use
429 webservices. The initial goal of the software was to support
430 Ajax-based applications, but there literally are no limits to what
431 you can do. You can use pazpar2 from Javascript, Flash, Java, etc.,
432 on the browser side, and from any development environment on the
433 server side, and you can pass session tokens and record IDs freely
434 around between these environments to build sophisticated applications.
435 Use your imagination.
439 The webservice API of pazpar2 is described in detail in <xref
440 linkend="pazpar2_protocol"/>.
444 In brief, you use the 'init' command to create a session, a
445 temporary workspace which carries information about the current
446 search. You start a new search using the 'search' command. Once the
447 search has been started, you can follow its progress using the
448 'stat', 'bytarget', 'termlist', or 'show' commands. Detailed records
449 can be fetched using the 'record' command.
453 <section id="nonstandard">
454 <title>Connecting to non-standard resources</title>
456 Pazpar2 uses Z39.50 as its switchboard language -- i.e. as far as it
457 is concerned, all resources speak Z39.50. It is, however, equipped
458 to handle a broad range of different server behavior, through
459 configurable query mapping and record normalization. If you develop
460 configuration, stylesheets, etc., for a new type of resources, we
461 encourage you to share your work. But you can also use pazpar2 to
462 connect to hundreds of resources that do not support standard
467 For a growing number of resources, Z39.50 is all you need. Over the
468 last few years, a number of commercial, full-text resources have
469 implemented Z39.50. These can be used through pazpar2 with little or
470 no effort. Resources that use non-standard record formats will
471 require a bit of XSLT work, but that's all.
475 But what about resources that don't support Z39.50 at all? The NISO
476 SRU (MXG) protocol is slowly gathering steam. Other resources might
477 support OpenSearch, private, XML/HTTP-based protocols, or something
478 else entirely. Some databases exist only as web user interfaces and
479 will require screen-scraping. Still others exist only as static
480 files, or perhaps as databases supporting the OAI-PMH protocol.
481 There is hope! Read on.
485 Index Data continues to advocate the support of open standards. We
486 work with database vendors to support standards, so you don't have
487 to worry about programming against non-standard services. We also
488 provide tools (see <ulink
489 url="http://www.indexdata.com/simpleserver">SimpleServer</ulink>)
490 which make it comparatively easy to build gateways against servers
491 with non-standard behavior. Again, we encourage you to share any
492 work you do in this direction.
496 But the bottom line is that working with non-standard resources in
497 metasearching is really, really hard. If you want to build a
498 project with pazpar2, and you need access to resources with
499 non-standard interfaces, we can help. We run gateways to more than
500 2,000 popular, commercial databases and other resources,
502 to plug them directly into pazpar2. For a small annual fee per
503 database, we can help you establish connections to your licensed
504 resources. Meanwhile, you can help! If you build your own
505 standards-compliant gateways, host them for others, or share the
506 code! And tell your vendors that they can save everybody money and
507 increase the appeal of their resources by supporting standards.
511 There are those who will ask us why we are using Z39.50 as our
512 switchboard langyage rather than a different protocol. Basically,
513 we believe that Z39.50 is presently the most widely implemented
514 information retrieval protocol that has the level of functionality
515 required to support a good metasearching experience (structured
516 searching, structured, well-defined results). It is also compact and
517 efficient, and there is a very broad range of tools available to
522 <section id="unicode">
523 <title>Unicode Compliance</title>
525 Pazpar2 is unicode compliant and language and locale aware to
526 the exted the used backend Z39.50 targets are. Just a few bad
527 behaving targets can spoil the search experience considerably
528 if for example Greek, Russian or otherwise non 7-bit ASCII
529 search terms are entered. In these cases some targets return
530 records irrelevant to the query, and the result screens wil be
531 cluttered with noise.
534 While noise from misbehaving targets can not be removed, it can
535 be reduced using truely unicode based ranking. This is an
536 option which is available to the system administrator if ICU
537 support is compiled into Pazpar2, see
538 <xref linkend="installation"/> for details.
541 In addition, the ICU tokenization and normalization rules must
542 be defined in the master configuration file described in
543 <xref linkend="config-server"/>.
547 </chapter> <!-- Using pazpar2 -->
549 <reference id="reference">
550 <title>Reference</title>
551 <partintro id="reference-introduction">
553 The material in this chapter is drawn directly from the individual
560 <appendix id="license"><title>License</title>
562 <section id="gpl"><title>GPL</title>
566 Copyright © ©right-year; Index Data.
570 Pazpar2 is free software; you can redistribute it and/or modify it under
571 the terms of the GNU General Public License as published by the Free
572 Software Foundation; either version 2, or (at your option) any later
577 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
578 WARRANTY; without even the implied warranty of MERCHANTABILITY or
579 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
584 You should have received a copy of the GNU General Public License
585 along with Pazpar2; see the file LICENSE. If not, write to the
586 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
591 GNU GENERAL PUBLIC LICENSE
594 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
595 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
596 Everyone is permitted to copy and distribute verbatim copies
597 of this license document, but changing it is not allowed.
601 The licenses for most software are designed to take away your
602 freedom to share and change it. By contrast, the GNU General Public
603 License is intended to guarantee your freedom to share and change free
604 software--to make sure the software is free for all its users. This
605 General Public License applies to most of the Free Software
606 Foundation's software and to any other program whose authors commit to
607 using it. (Some other Free Software Foundation software is covered by
608 the GNU Library General Public License instead.) You can apply it to
611 When we speak of free software, we are referring to freedom, not
612 price. Our General Public Licenses are designed to make sure that you
613 have the freedom to distribute copies of free software (and charge for
614 this service if you wish), that you receive source code or can get it
615 if you want it, that you can change the software or use pieces of it
616 in new free programs; and that you know you can do these things.
618 To protect your rights, we need to make restrictions that forbid
619 anyone to deny you these rights or to ask you to surrender the rights.
620 These restrictions translate to certain responsibilities for you if you
621 distribute copies of the software, or if you modify it.
623 For example, if you distribute copies of such a program, whether
624 gratis or for a fee, you must give the recipients all the rights that
625 you have. You must make sure that they, too, receive or can get the
626 source code. And you must show them these terms so they know their
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630 (2) offer you this license which gives you legal permission to copy,
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634 that everyone understands that there is no warranty for this free
635 software. If the software is modified by someone else and passed on, we
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640 Finally, any free program is threatened constantly by software
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644 patent must be licensed for everyone's free use or not licensed at all.
646 The precise terms and conditions for copying, distribution and
649 GNU GENERAL PUBLIC LICENSE
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796 all those who receive copies directly or indirectly through you, then
797 the only way you could satisfy both it and this License would be to
798 refrain entirely from distribution of the Program.
800 If any portion of this section is held invalid or unenforceable under
801 any particular circumstance, the balance of the section is intended to
802 apply and the section as a whole is intended to apply in other
805 It is not the purpose of this section to induce you to infringe any
806 patents or other property right claims or to contest validity of any
807 such claims; this section has the sole purpose of protecting the
808 integrity of the free software distribution system, which is
809 implemented by public license practices. Many people have made
810 generous contributions to the wide range of software distributed
811 through that system in reliance on consistent application of that
812 system; it is up to the author/donor to decide if he or she is willing
813 to distribute software through any other system and a licensee cannot
816 This section is intended to make thoroughly clear what is believed to
817 be a consequence of the rest of this License.
819 8. If the distribution and/or use of the Program is restricted in
820 certain countries either by patents or by copyrighted interfaces, the
821 original copyright holder who places the Program under this License
822 may add an explicit geographical distribution limitation excluding
823 those countries, so that distribution is permitted only in or among
824 countries not thus excluded. In such case, this License incorporates
825 the limitation as if written in the body of this License.
827 9. The Free Software Foundation may publish revised and/or new versions
828 of the General Public License from time to time. Such new versions will
829 be similar in spirit to the present version, but may differ in detail to
830 address new problems or concerns.
832 Each version is given a distinguishing version number. If the Program
833 specifies a version number of this License which applies to it and "any
834 later version", you have the option of following the terms and conditions
835 either of that version or of any later version published by the Free
836 Software Foundation. If the Program does not specify a version number of
837 this License, you may choose any version ever published by the Free Software
840 10. If you wish to incorporate parts of the Program into other free
841 programs whose distribution conditions are different, write to the author
842 to ask for permission. For software which is copyrighted by the Free
843 Software Foundation, write to the Free Software Foundation; we sometimes
844 make exceptions for this. Our decision will be guided by the two goals
845 of preserving the free status of all derivatives of our free software and
846 of promoting the sharing and reuse of software generally.
850 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
851 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
852 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
853 PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
854 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
855 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
856 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
857 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
858 REPAIR OR CORRECTION.
860 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
861 WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
862 REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
863 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
864 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
865 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
866 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
867 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
868 POSSIBILITY OF SUCH DAMAGES.
870 END OF TERMS AND CONDITIONS
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