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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>
22 <releaseinfo>&version;</releaseinfo>
24 <year>©right-year;</year>
25 <holder>Index Data</holder>
29 Pazpar2 is a high-performance, user interface-independent, data
30 model-independent metasearching
31 middleware featuring merging, relevance ranking, record sorting,
35 This document is a guide and reference to Pazpar version &version;.
40 <imagedata fileref="common/id.png" format="PNG"/>
43 <imagedata fileref="common/id.eps" format="EPS"/>
50 <chapter id="introduction">
51 <title>Introduction</title>
53 Pazpar2 is a stand-alone metasearch client with a webservice API, designed
54 to be used either from a browser-based client (JavaScript, Flash, Java,
55 etc.), from from server-side code, or any combination of the two.
56 Pazpar2 is a highly optimized client designed to
57 search many resources in parallel. It implements record merging,
58 relevance-ranking and sorting by arbitrary data content, and facet
59 analysis for browsing purposes. It is designed to be data model
60 independent, and is capable of working with MARC, DublinCore, or any
61 other XML-structured response format -- XSLT is used to normalize and extract
62 data from retrieval records for display and analysis. It can be used
63 against any server which supports the Z39.50 protocol. Proprietary
64 backend modules can be used to support a large number of other protocols
65 (please contact Index Data for further information about this).
68 Additional functionality such as
69 user management, attractive displays are expected to be implemented by
70 applications that use pazpar2. Pazpar2 is user interface independent.
71 Its functionality is exposed through a simple REST-style webservice API,
72 designed to be simple to use from an Ajax-enbled browser, Flash
73 animation, Java applet, etc., or from a higher-level server-side language
74 like PHP or Java. Because session information can be shared between
75 browser-based logic and your server-side scripting, there is tremendous
76 flexibility in how you implement your business logic on top of pazpar2.
79 Once you launch a search in pazpar2, the operation continues behind the
80 scenes. Pazpar2 connects to servers, carries out searches, and
81 retrieves, deduplicates, and stores results internally. Your application
82 code may periodically inquire about the status of an ongoing operation,
83 and ask to see records or other result set facets. Result become
84 available immediately, and it is easy to build end-user interfaces which
85 feel extremely responsive, even when searching more than 100 servers
89 Pazpar2 is designed to be highly configurable. Incoming records are
90 normalized to XML/UTF-8, and then further normalized using XSLT to a
91 simple internal representation that is suitable for analysis. By
92 providing XSLT stylesheets for different kinds of result records, you
93 can tune pazpar2 to work against different kinds of information
94 retrieval servers. Finally, metadata is extracted, in a configurable
95 way, from this internal record, to support display, merging, ranking,
96 result set facets, and sorting. Pazpar2 is not bound to a specific model
97 of metadata, such as DublinCore or MARC -- by providing the right
98 configuration, it can work with a number of different kinds of data in
99 support of many different applications.
102 Pazpar2 is designed to be efficient and scalable. You can set it up to
103 search several hundred targets in parallel, or you can use it to support
104 hundreds of concurrent users. It is implemented with the same attention
105 to performance and economy that we use in our indexing engines, so that
106 you can focus on building your application, without worrying about the
107 details of metasearch logic. You can devote all of your attention to
108 usability and let pazpar2 do what it does best -- metasearch.
111 If you wish to connect to commercial or other databases which do not
112 support open standards, please contact Index Data. We have a licensing
113 agreement with a third party vendor which will enable pazpar2 to access
114 thousands of online databases, in addition the vast number of catalogs
115 and online services that support the Z39.50 protocol.
118 Pazpar2 is our attempt to re-think the traditional paradigms for
119 implementing and deploying metasearch logic, with an uncompromising
120 approach to performance, and attempting to make maximum use of the
121 capabilities of modern browsers. The demo user interface that
122 accompanies the distribution is but one example. If you think of new
123 ways of using pazpar2, we hope you'll share them with us, and if we
124 can provide assistance with regards to training, design, programming,
125 integration with different backends, hosting, or support, please don't
126 hesitate to contact us. If you'd like to see functionality in pazpar2
127 that is not there today, please don't hesitate to contact us. It may
128 already be in our development pipeline, or there might be a
129 possibility for you to help out by sponsoring development time or
130 code. Either way, get in touch and we will give you straight answers.
136 Pazpar2 is covered by the GNU license version 2.
137 See <xref linkend="license"/> for further information.
141 <chapter id="installation">
142 <title>Installation</title>
144 Pazpar2 depends on the following tools/libraries:
146 <varlistentry><term><ulink url="&url.yaz;">YAZ</ulink></term>
149 The popular Z39.50 toolkit for the C language. YAZ must be
150 compiled with Libxml2/Libxslt support.
157 In order to compile Pazpar2 an ANSI C compiler is
158 required. The requirements should be the same as for YAZ.
161 <section id="installation.unix">
162 <title>Installation on Unix (from Source)</title>
164 Here is a quick step-by-step guide on how to compile the
165 tools that Pazpar2 uses. Only few systems have none of the required
166 tools binary packages. If, for example, Libxml2/libxslt are already
167 installed as development packages use these.
171 Ensure that the development libraries + header files are
172 available on your system before compiling Pazpar2. For installation
173 of YAZ, refer to the YAZ installation chapter.
176 gunzip -c pazpar2-version.tar.gz|tar xf -
185 <section id="installation.debian">
186 <title>Installation on Debian GNU/Linux</title>
188 All dependencies for Pazpar2 are available as
189 <ulink url="&url.debian;">Debian</ulink>
190 packages for the sarge (stable in 2005) and etch (testing in 2005)
194 The procedures for Debian based systems, such as
195 <ulink url="&url.ubuntu;">Ubuntu</ulink> is probably similar
198 apt-get install libyaz-dev
201 With these packages installed, the usual configure + make
202 procedure can be used for Pazpar2 as outlined in
203 <xref linkend="installation.unix"/>.
209 <title>Using pazpar2</title>
211 This chapter provides a general introduction to the use and deployment of pazpar2.
214 <section id="architecture">
215 <title>Pazpar2 and your systems architecture</title>
217 Pazpar2 is designed to provide asynchronous, behind-the-scenes
218 metasearching functionality to your application, exposing this
219 functionality using a simple webservice API that can be accessed
220 from any number of development environments. In particular, it is
221 possible to combine pazpar2 either with your server-side dynamic
222 website scripting, with scripting or code running in the browser, or
223 with any combination of the two. Pazpar2 is an excellent tool for
224 building advanced, Ajax-based user interfaces for metasearch
225 functionality, but it isn't a requirement -- you can choose to use
226 pazpar2 entirely as a backend to your regular server-side scripting.
227 When you do use pazpar2 in conjunction
228 with browser scripting (JavaScript/Ajax, Flash, applets, etc.), there are
229 special considerations.
233 Pazpar2 implements a simple but efficient HTTP server, and it is
234 designed to interact directly with scripting running in the browser
235 for the best possible performance, and to limit overhead when
236 several browser clients generate numerous webservice requests.
237 However, it is still desirable to use a conventional webserver,
238 such as Apache, to serve up graphics, HTML documents, and
239 server-side scripting. Because the security sandbox environment of
240 most browser-side programming environments only allows communication
241 with the server from which the enclosing HTML page or object
242 originated, pazpar2 is designed so that it can act as a transparent
243 proxy in front of an existing webserver (see <xref
244 linkend="pazpar2_conf"/> for details). In this mode, all regular
245 HTTP requests are transparently passed through to your webserver,
246 while pazpar2 only intercepts search-related webservice requests.
250 If you want to expose your combined service on port 80, you can
251 either run your regular webserver on a different port, a different
252 server, or a different IP address associated with the same server.
256 Sometimes, it may be necessary to implement functionality on your
257 regular webserver that makes use of search results, for example to
258 implement data import functionality, emailing results, history
259 lists, personal citation lists, interlibrary loan functionality
260 ,etc. Fortunately, it is simple to exchange information between
261 pazpar2, your browser scripting, and backend server-side scripting.
262 You can send a session ID and possibly a record ID from your browser
263 code to your server code, and from there use pazpar2s webservice API
264 to access result sets or individual records. You could even 'hide'
265 all of pazpar2s functionality between your own API implemented on
266 the server-side, and access that from the browser or elsewhere. The
267 possibilities are just about endless.
271 <section id="data_model">
272 <title>Your data model</title>
274 Pazpar2 does not have a preconceived model of what makes up a data
275 model. There are no assumption that records have specific fields or
276 that they are organized in any particular way. The only assumption
277 is that data comes packaged in a form that the software can work
278 with (presently, that means XML or MARC), and that you can provide
279 the necessary information to massage it into pazpar2's internal
284 Handling retrieval records in pazpar2 is a two-step process. First,
285 you decide which data elements of the source record you are
286 interested in, and you specify any desired massaging or combining of
287 elements using an XSLT stylesheet (MARC records are automatically
288 normalized to MARCXML before this step). If desired, you can run
289 multiple XSLT stylesheets in series to accomplish this, but the
290 output of the last one should be a representation of the record in a
291 schema that pazpar2 understands.
295 The intermediate, internal representation of the record looks like
298 <record xmlns="http://www.indexdata.com/pazpar2/1.0"
299 mergekey="title The Shining author King, Stephen">
301 <metadata type="title">The Shining</metadata>
303 <metadata type="author">King, Stephen</metadata>
305 <metadata type="kind">ebook</metadata>
307 <!-- ... and so on -->
311 As you can see, there isn't much to it. There are really only a few
312 important elements to this file.
316 Elements should belong to the namespace
317 http://www.indexdata.com/pazpar2/1.0. If the root node contains the
318 attribute 'mergekey', then every record that generates the same
319 merge key (normalized for case differences, white space, and
320 truncation) will be joined into a cluster. In other words, you
321 decide how records are merged. If you don't include a merge key,
322 records are never merged. The 'metadata' elements provide the meat
323 of the elements -- the content. the 'type' attribute is used to
324 match each element against processing rules that determine what
325 happens to the data element next.
329 The next processing step is the extraction of metadata from the
330 intermediate representation of the record. This is governed by the
331 'metadata' elements in the 'service' section of the configuration
332 file. See <xref linkend="config-server"/> for details. The metadata
333 in the retrieval record ultimately drives merging, sorting, ranking,
334 the extraction of browse facets, and display, all configurable.
338 <section id="client">
339 <title>Client development overview</title>
341 You can use pazpar2 from any environment that allows you to use
342 webservices. The initial goal of the software was to support
343 Ajax-based applications, but there literally are no limits to what
344 you can do. You can use pazpar2 from Javascript, Flash, Java, etc.,
345 on the browser side, and from any development environment on the
346 server side, and you can pass session tokens and record IDs freely
347 around between these environments to build sophisticated applications.
348 Use your imagination.
352 The webservice API of pazpar2 is described in detail in <xref
353 linkend="pazpar2_protocol"/>.
357 In brief, you use the 'init' command to create a session, a
358 temporary workspace which carries information about the current
359 search. You start a new search using the 'search' command. Once the
360 search has been started, you can follow its progress using the
361 'stat', 'bytarget', 'termlist', or 'show' commands. Detailed records
362 can be fetched using the 'record' command.
366 <section id="nonstandard">
367 <title>Connecting to non-standard resources</title>
369 Pazpar2 uses Z39.50 as its switchboard language -- i.e. as far as it
370 is concerned, all resources speak Z39.50. It is, however, equipped
371 to handle a broad range of different server behavior, through
372 configurable query mapping and record normalization. If you develop
373 configuration, stylesheets, etc., for a new type of resources, we
374 encourage you to share your work. But you can also use pazpar2 to
375 connect to hundreds of resources that do not support standard
380 For a growing number of resources, Z39.50 is all you need. Over the
381 last few years, a number of commercial, full-text resources have
382 implemented Z39.50. These can be used through pazpar2 with little or
383 no effort. Resources that use non-standard record formats will
384 require a bit of XSLT work, but that's all.
388 But what about resources that don't support Z39.50 at all? The NISO
389 SRU (MXG) protocol is slowly gathering steam. Other resources might
390 support OpenSearch, private, XML/HTTP-based protocols, or something
391 else entirely. Some databases exist only as web user interfaces and
392 will require screen-scraping. Still others exist only as static
393 files, or perhaps as databases supporting the OAI-PMH protocol.
394 There is hope! Read on.
398 Index Data continues to advocate the support of open standards. We
399 work with database vendors to support standards, so you don't have
400 to worry about programming against non-standard services. We also
401 provide tools (see <ulink
402 url="http://www.indexdata.com/simpleserver">SimpleServer</ulink>)
403 which make it comparatively easy to build gateways against servers
404 with non-standard behavior. Again, we encourage you to share any
405 work you do in this direction.
409 But the bottom line is that working with non-standard resources in
410 metasearching is really, really hard. If you want to build a
411 project with pazpar2, and you need access to resources with
412 non-standard interfaces, we can help. We run gateways to more than
413 2,000 popular, commercial databases and other resources, making it simple
414 to plug them directly into pazpar2. For a small annual fee per
415 database, we can help you establish connections to your licensed
416 resources. Meanwhile, you can help! If you build your own
417 standards-compliant gateways, host them for others, or share the
418 code! And tell your vendors that they can save everybody money and
419 increase the appeal of their resources by supporting standards.
423 There are those who will ask us why we are using Z39.50 as our
424 switchboard langyage rather than a different protocol. Basically,
425 we believe that Z39.50 is presently the most widely implemented
426 information retrieval protocol that has the level of functionality
427 required to support a good metasearching experience (structured
428 searching, structured, well-defined results). It is also compact and
429 efficient, and there is a very broad range of tools available to
433 </chapter> <!-- Using pazpar2 -->
435 <reference id="reference">
436 <title>Reference</title>
439 The material in this chapter is drawn directly from the individual
446 <appendix id="license"><title>License</title>
448 <section id="gpl"><title>GPL</title>
452 Copyright © ©right-year; Index Data.
456 Pazpar2 is free software; you can redistribute it and/or modify it under
457 the terms of the GNU General Public License as published by the Free
458 Software Foundation; either version 2, or (at your option) any later
463 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
464 WARRANTY; without even the implied warranty of MERCHANTABILITY or
465 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
470 You should have received a copy of the GNU General Public License
471 along with Pazpar2; see the file LICENSE. If not, write to the
472 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
477 GNU GENERAL PUBLIC LICENSE
480 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
481 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
482 Everyone is permitted to copy and distribute verbatim copies
483 of this license document, but changing it is not allowed.
487 The licenses for most software are designed to take away your
488 freedom to share and change it. By contrast, the GNU General Public
489 License is intended to guarantee your freedom to share and change free
490 software--to make sure the software is free for all its users. This
491 General Public License applies to most of the Free Software
492 Foundation's software and to any other program whose authors commit to
493 using it. (Some other Free Software Foundation software is covered by
494 the GNU Library General Public License instead.) You can apply it to
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498 price. Our General Public Licenses are designed to make sure that you
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749 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
750 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
751 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
752 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
753 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
754 POSSIBILITY OF SUCH DAMAGES.
756 END OF TERMS AND CONDITIONS
763 <!-- Keep this comment at the end of the file
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