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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 XML-structured response format -- XSLT is used to normalize and extract
65 data from retrieval records for display and analysis. It can be used
66 against any server which supports the Z39.50 protocol. Proprietary
67 backend modules can be used to support a large number of other protocols
68 (please contact Index Data for further information about this).
71 Additional functionality such as
72 user management, attractive displays are expected to be implemented by
73 applications that use pazpar2. Pazpar2 is user interface independent.
74 Its functionality is exposed through a simple REST-style webservice API,
75 designed to be simple to use from an Ajax-enbled browser, Flash
76 animation, Java applet, etc., or from a higher-level server-side language
77 like PHP or Java. Because session information can be shared between
78 browser-based logic and your server-side scripting, there is tremendous
79 flexibility in how you implement your business logic on top of pazpar2.
82 Once you launch a search in pazpar2, the operation continues behind the
83 scenes. Pazpar2 connects to servers, carries out searches, and
84 retrieves, deduplicates, and stores results internally. Your application
85 code may periodically inquire about the status of an ongoing operation,
86 and ask to see records or other result set facets. Result become
87 available immediately, and it is easy to build end-user interfaces which
88 feel extremely responsive, even when searching more than 100 servers
92 Pazpar2 is designed to be highly configurable. Incoming records are
93 normalized to XML/UTF-8, and then further normalized using XSLT to a
94 simple internal representation that is suitable for analysis. By
95 providing XSLT stylesheets for different kinds of result records, you
96 can tune pazpar2 to work against different kinds of information
97 retrieval servers. Finally, metadata is extracted, in a configurable
98 way, from this internal record, to support display, merging, ranking,
99 result set facets, and sorting. Pazpar2 is not bound to a specific model
100 of metadata, such as DublinCore or MARC -- by providing the right
101 configuration, it can work with a number of different kinds of data in
102 support of many different applications.
105 Pazpar2 is designed to be efficient and scalable. You can set it up to
106 search several hundred targets in parallel, or you can use it to support
107 hundreds of concurrent users. It is implemented with the same attention
108 to performance and economy that we use in our indexing engines, so that
109 you can focus on building your application, without worrying about the
110 details of metasearch logic. You can devote all of your attention to
111 usability and let pazpar2 do what it does best -- metasearch.
114 If you wish to connect to commercial or other databases which do not
115 support open standards, please contact Index Data. We have a licensing
116 agreement with a third party vendor which will enable pazpar2 to access
117 thousands of online databases, in addition the vast number of catalogs
118 and online services that support the Z39.50 protocol.
121 Pazpar2 is our attempt to re-think the traditional paradigms for
122 implementing and deploying metasearch logic, with an uncompromising
123 approach to performance, and attempting to make maximum use of the
124 capabilities of modern browsers. The demo user interface that
125 accompanies the distribution is but one example. If you think of new
126 ways of using pazpar2, we hope you'll share them with us, and if we
127 can provide assistance with regards to training, design, programming,
128 integration with different backends, hosting, or support, please don't
129 hesitate to contact us. If you'd like to see functionality in pazpar2
130 that is not there today, please don't hesitate to contact us. It may
131 already be in our development pipeline, or there might be a
132 possibility for you to help out by sponsoring development time or
133 code. Either way, get in touch and we will give you straight answers.
139 Pazpar2 is covered by the GNU license version 2.
140 See <xref linkend="license"/> for further information.
144 <chapter id="installation">
145 <title>Installation</title>
147 Pazpar2 depends on the following tools/libraries:
149 <varlistentry><term><ulink url="&url.yaz;">YAZ</ulink></term>
152 The popular Z39.50 toolkit for the C language. YAZ must be
153 compiled with Libxml2/Libxslt support.
157 <varlistentry><term><ulink url="&url.icu;">International
158 Components for Unicode (ICU)</ulink></term>
161 ICU provides Unicode support for non-english languages with
162 character sets outside the range of 7bit ASCII, like
163 Greek, Russian, German and Frensh. Pazpar2 uses the ICU
164 unicode character conversions, unicode normalization, case
165 folding and other fundamental operations needed in
166 tokenization, normalization and ranking of records.
169 Compiling, linking, and usage of the ICU libraries is optional,
170 but strongly recommended for usage in an international
178 In order to compile Pazpar2 an ANSI C compiler is
179 required. The requirements should be the same as for YAZ.
182 <section id="installation.unix">
183 <title>Installation on Unix (from Source)</title>
185 Here is a quick step-by-step guide on how to compile the
186 tools that Pazpar2 uses. Only few systems have none of the required
187 tools binary packages. If, for example, Libxml2/libxslt are already
188 installed as development packages use these.
192 Ensure that the development libraries + header files are
193 available on your system before compiling Pazpar2. For installation
194 of YAZ, refer to the YAZ installation chapter.
197 gunzip -c pazpar2-version.tar.gz|tar xf -
206 <section id="installation.debian">
207 <title>Installation on Debian GNU/Linux</title>
209 All dependencies for Pazpar2 are available as
210 <ulink url="&url.debian;">Debian</ulink>
211 packages for the sarge (stable in 2005) and etch (testing in 2005)
215 The procedures for Debian based systems, such as
216 <ulink url="&url.ubuntu;">Ubuntu</ulink> is probably similar
219 apt-get install libyaz-dev
220 apt-get install libicu36-dev
223 With these packages installed, the usual configure + make
224 procedure can be used for Pazpar2 as outlined in
225 <xref linkend="installation.unix"/>.
229 <section id="installation.apache2proxy">
230 <title>Apache 2 Proxy</title>
233 <ulink url="http://httpd.apache.org/docs/2.2/mod/mod_proxy.html">
235 </ulink> which allows Pazpar2 to become a backend to an Apache 2
236 based web service. The Apache 2 proxy must operate in the
237 <emphasis>Reverse</emphasis> Proxy mode.
241 On a Debian based Apache 2 system, the relevant modules can
244 sudo a2enmod proxy_http
249 Traditionnally Pazpar2 interprets URL paths with suffix
250 <literal>/search.pz2</literal>.
251 The <literal>ProxyPass</literal> must be configured with this
252 path and the address of the Pazpar2 server (listening port).
257 Since the ProxyPass directive takes a prefix rather than
258 a suffix as URL path it is important that the Java Script code
259 uses <literal>/search.pz2</literal> rather than just
260 <literal>search.pz2</literal>.
264 <example id="installation.apache2proxy.example">
265 <title>Apache 2 proxy configuration</title>
267 If Pazpar2 is running on port 9004 we can use the following
268 Apache 2 configuration:
271 <IfModule mod_proxy.c>
275 AddDefaultCharset off
280 ProxyPass /search.pz2 http://localhost:9004/search.pz2
291 <title>Using pazpar2</title>
293 This chapter provides a general introduction to the use and
294 deployment of pazpar2.
297 <section id="architecture">
298 <title>Pazpar2 and your systems architecture</title>
300 Pazpar2 is designed to provide asynchronous, behind-the-scenes
301 metasearching functionality to your application, exposing this
302 functionality using a simple webservice API that can be accessed
303 from any number of development environments. In particular, it is
304 possible to combine pazpar2 either with your server-side dynamic
305 website scripting, with scripting or code running in the browser, or
306 with any combination of the two. Pazpar2 is an excellent tool for
307 building advanced, Ajax-based user interfaces for metasearch
308 functionality, but it isn't a requirement -- you can choose to use
309 pazpar2 entirely as a backend to your regular server-side scripting.
310 When you do use pazpar2 in conjunction
311 with browser scripting (JavaScript/Ajax, Flash, applets,
312 etc.), there are special considerations.
316 Pazpar2 implements a simple but efficient HTTP server, and it is
317 designed to interact directly with scripting running in the browser
318 for the best possible performance, and to limit overhead when
319 several browser clients generate numerous webservice requests.
320 However, it is still desirable to use a conventional webserver,
321 such as Apache, to serve up graphics, HTML documents, and
322 server-side scripting. Because the security sandbox environment of
323 most browser-side programming environments only allows communication
324 with the server from which the enclosing HTML page or object
325 originated, pazpar2 is designed so that it can act as a transparent
326 proxy in front of an existing webserver (see <xref
327 linkend="pazpar2_conf"/> for details). In this mode, all regular
328 HTTP requests are transparently passed through to your webserver,
329 while pazpar2 only intercepts search-related webservice requests.
333 If you want to expose your combined service on port 80, you can
334 either run your regular webserver on a different port, a different
335 server, or a different IP address associated with the same server.
339 Sometimes, it may be necessary to implement functionality on your
340 regular webserver that makes use of search results, for example to
341 implement data import functionality, emailing results, history
342 lists, personal citation lists, interlibrary loan functionality
343 ,etc. Fortunately, it is simple to exchange information between
344 pazpar2, your browser scripting, and backend server-side scripting.
345 You can send a session ID and possibly a record ID from your browser
346 code to your server code, and from there use pazpar2s webservice API
347 to access result sets or individual records. You could even 'hide'
348 all of pazpar2s functionality between your own API implemented on
349 the server-side, and access that from the browser or elsewhere. The
350 possibilities are just about endless.
354 <section id="data_model">
355 <title>Your data model</title>
357 Pazpar2 does not have a preconceived model of what makes up a data
358 model. There are no assumption that records have specific fields or
359 that they are organized in any particular way. The only assumption
360 is that data comes packaged in a form that the software can work
361 with (presently, that means XML or MARC), and that you can provide
362 the necessary information to massage it into pazpar2's internal
367 Handling retrieval records in pazpar2 is a two-step process. First,
368 you decide which data elements of the source record you are
369 interested in, and you specify any desired massaging or combining of
370 elements using an XSLT stylesheet (MARC records are automatically
371 normalized to MARCXML before this step). If desired, you can run
372 multiple XSLT stylesheets in series to accomplish this, but the
373 output of the last one should be a representation of the record in a
374 schema that pazpar2 understands.
378 The intermediate, internal representation of the record looks like
381 <record xmlns="http://www.indexdata.com/pazpar2/1.0"
382 mergekey="title The Shining author King, Stephen">
384 <metadata type="title">The Shining</metadata>
386 <metadata type="author">King, Stephen</metadata>
388 <metadata type="kind">ebook</metadata>
390 <!-- ... and so on -->
394 As you can see, there isn't much to it. There are really only a few
395 important elements to this file.
399 Elements should belong to the namespace
400 http://www.indexdata.com/pazpar2/1.0. If the root node contains the
401 attribute 'mergekey', then every record that generates the same
402 merge key (normalized for case differences, white space, and
403 truncation) will be joined into a cluster. In other words, you
404 decide how records are merged. If you don't include a merge key,
405 records are never merged. The 'metadata' elements provide the meat
406 of the elements -- the content. the 'type' attribute is used to
407 match each element against processing rules that determine what
408 happens to the data element next.
412 The next processing step is the extraction of metadata from the
413 intermediate representation of the record. This is governed by the
414 'metadata' elements in the 'service' section of the configuration
415 file. See <xref linkend="config-server"/> for details. The metadata
416 in the retrieval record ultimately drives merging, sorting, ranking,
417 the extraction of browse facets, and display, all configurable.
421 <section id="client">
422 <title>Client development overview</title>
424 You can use pazpar2 from any environment that allows you to use
425 webservices. The initial goal of the software was to support
426 Ajax-based applications, but there literally are no limits to what
427 you can do. You can use pazpar2 from Javascript, Flash, Java, etc.,
428 on the browser side, and from any development environment on the
429 server side, and you can pass session tokens and record IDs freely
430 around between these environments to build sophisticated applications.
431 Use your imagination.
435 The webservice API of pazpar2 is described in detail in <xref
436 linkend="pazpar2_protocol"/>.
440 In brief, you use the 'init' command to create a session, a
441 temporary workspace which carries information about the current
442 search. You start a new search using the 'search' command. Once the
443 search has been started, you can follow its progress using the
444 'stat', 'bytarget', 'termlist', or 'show' commands. Detailed records
445 can be fetched using the 'record' command.
449 <section id="nonstandard">
450 <title>Connecting to non-standard resources</title>
452 Pazpar2 uses Z39.50 as its switchboard language -- i.e. as far as it
453 is concerned, all resources speak Z39.50. It is, however, equipped
454 to handle a broad range of different server behavior, through
455 configurable query mapping and record normalization. If you develop
456 configuration, stylesheets, etc., for a new type of resources, we
457 encourage you to share your work. But you can also use pazpar2 to
458 connect to hundreds of resources that do not support standard
463 For a growing number of resources, Z39.50 is all you need. Over the
464 last few years, a number of commercial, full-text resources have
465 implemented Z39.50. These can be used through pazpar2 with little or
466 no effort. Resources that use non-standard record formats will
467 require a bit of XSLT work, but that's all.
471 But what about resources that don't support Z39.50 at all? The NISO
472 SRU (MXG) protocol is slowly gathering steam. Other resources might
473 support OpenSearch, private, XML/HTTP-based protocols, or something
474 else entirely. Some databases exist only as web user interfaces and
475 will require screen-scraping. Still others exist only as static
476 files, or perhaps as databases supporting the OAI-PMH protocol.
477 There is hope! Read on.
481 Index Data continues to advocate the support of open standards. We
482 work with database vendors to support standards, so you don't have
483 to worry about programming against non-standard services. We also
484 provide tools (see <ulink
485 url="http://www.indexdata.com/simpleserver">SimpleServer</ulink>)
486 which make it comparatively easy to build gateways against servers
487 with non-standard behavior. Again, we encourage you to share any
488 work you do in this direction.
492 But the bottom line is that working with non-standard resources in
493 metasearching is really, really hard. If you want to build a
494 project with pazpar2, and you need access to resources with
495 non-standard interfaces, we can help. We run gateways to more than
496 2,000 popular, commercial databases and other resources,
498 to plug them directly into pazpar2. For a small annual fee per
499 database, we can help you establish connections to your licensed
500 resources. Meanwhile, you can help! If you build your own
501 standards-compliant gateways, host them for others, or share the
502 code! And tell your vendors that they can save everybody money and
503 increase the appeal of their resources by supporting standards.
507 There are those who will ask us why we are using Z39.50 as our
508 switchboard langyage rather than a different protocol. Basically,
509 we believe that Z39.50 is presently the most widely implemented
510 information retrieval protocol that has the level of functionality
511 required to support a good metasearching experience (structured
512 searching, structured, well-defined results). It is also compact and
513 efficient, and there is a very broad range of tools available to
518 <section id="unicode">
519 <title>Unicode Compliance</title>
521 Pazpar2 is unicode compliant and language and locale aware to
522 the exted the used backend Z39.50 targets are. Just a few bad
523 behaving targets can spoil the search experience considerably
524 if for example Greek, Russian or otherwise non 7-bit ASCII
525 search terms are entered. In these cases some targets return
526 records irrelevant to the query, and the result screens wil be
527 cluttered with noise.
530 While noise from misbehaving targets can not be removed, it can
531 be reduced using truely unicode based ranking. This is an
532 option which is available to the system administrator if ICU
533 support is compiled into Pazpar2, see
534 <xref linkend="installation"/> for details.
537 In addition, the ICU tokenization and normalization rules must
538 be defined in the master configuration file described in
539 <xref linkend="config-server"/>.
543 </chapter> <!-- Using pazpar2 -->
545 <reference id="reference">
546 <title>Reference</title>
547 <partintro id="reference-introduction">
549 The material in this chapter is drawn directly from the individual
556 <appendix id="license"><title>License</title>
558 <section id="gpl"><title>GPL</title>
562 Copyright © ©right-year; Index Data.
566 Pazpar2 is free software; you can redistribute it and/or modify it under
567 the terms of the GNU General Public License as published by the Free
568 Software Foundation; either version 2, or (at your option) any later
573 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
574 WARRANTY; without even the implied warranty of MERCHANTABILITY or
575 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
580 You should have received a copy of the GNU General Public License
581 along with Pazpar2; see the file LICENSE. If not, write to the
582 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
587 GNU GENERAL PUBLIC LICENSE
590 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
591 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
592 Everyone is permitted to copy and distribute verbatim copies
593 of this license document, but changing it is not allowed.
597 The licenses for most software are designed to take away your
598 freedom to share and change it. By contrast, the GNU General Public
599 License is intended to guarantee your freedom to share and change free
600 software--to make sure the software is free for all its users. This
601 General Public License applies to most of the Free Software
602 Foundation's software and to any other program whose authors commit to
603 using it. (Some other Free Software Foundation software is covered by
604 the GNU Library General Public License instead.) You can apply it to
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608 price. Our General Public Licenses are designed to make sure that you
609 have the freedom to distribute copies of free software (and charge for
610 this service if you wish), that you receive source code or can get it
611 if you want it, that you can change the software or use pieces of it
612 in new free programs; and that you know you can do these things.
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804 integrity of the free software distribution system, which is
805 implemented by public license practices. Many people have made
806 generous contributions to the wide range of software distributed
807 through that system in reliance on consistent application of that
808 system; it is up to the author/donor to decide if he or she is willing
809 to distribute software through any other system and a licensee cannot
812 This section is intended to make thoroughly clear what is believed to
813 be a consequence of the rest of this License.
815 8. If the distribution and/or use of the Program is restricted in
816 certain countries either by patents or by copyrighted interfaces, the
817 original copyright holder who places the Program under this License
818 may add an explicit geographical distribution limitation excluding
819 those countries, so that distribution is permitted only in or among
820 countries not thus excluded. In such case, this License incorporates
821 the limitation as if written in the body of this License.
823 9. The Free Software Foundation may publish revised and/or new versions
824 of the General Public License from time to time. Such new versions will
825 be similar in spirit to the present version, but may differ in detail to
826 address new problems or concerns.
828 Each version is given a distinguishing version number. If the Program
829 specifies a version number of this License which applies to it and "any
830 later version", you have the option of following the terms and conditions
831 either of that version or of any later version published by the Free
832 Software Foundation. If the Program does not specify a version number of
833 this License, you may choose any version ever published by the Free Software
836 10. If you wish to incorporate parts of the Program into other free
837 programs whose distribution conditions are different, write to the author
838 to ask for permission. For software which is copyrighted by the Free
839 Software Foundation, write to the Free Software Foundation; we sometimes
840 make exceptions for this. Our decision will be guided by the two goals
841 of preserving the free status of all derivatives of our free software and
842 of promoting the sharing and reuse of software generally.
846 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
847 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
848 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
849 PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
850 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
851 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
852 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
853 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
854 REPAIR OR CORRECTION.
856 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
857 WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
858 REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
859 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
860 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
861 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
862 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
863 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
864 POSSIBILITY OF SUCH DAMAGES.
866 END OF TERMS AND CONDITIONS
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