<?xml version="1.0" encoding="UTF-8"?>
<section id="ajaxdev">
- <title>Ajax client development</title>
-
- <para>
- Pazpar2 offers programmer a simple Web Service protocol that can be used (queried in a request/response fashion) from any, server- or client-side, programming language with an XML support. However, when programming a Web-based client to Pazpar2, to achieve certain level of interactivity and instant notification of latest changes in the result set, Ajax (Asynchronous JavaScript and XML) technology may be used. An Ajax client allows user to browse the results before the lengthy process of information retrieval from the back-end targets is finished. Blocking and waiting for usually slow back-end targets is one of the biggest functionality issues in a federated search engine.
- </para>
-
- <para><bridgehead>Pz2.js</bridgehead></para>
-
- <para>
- Pazpar2 comes with a small JavaScript library called pz2.js. This library is designed to simplify development of an Ajax-based pazpar2 client and alleviate programmer from the low-level details like polling the web service, fetching and parsing returned XML output or managing timers, sessions and basic state variables.
- </para>
-
- <para>
- The library supports most major browsers including Firefox 1.5+, IE 6+, Safari 2+, Opera 9+ and Konqueror.
- </para>
-
- <para>
- The library can work in two modes: a session-aware mode and a session-less mode.
- </para>
-
- <para>In the session-aware mode, the library assumes that the pazpar2 daemon is contacted directly (preferably via Apache proxy to avoid security breaches) and tracks the session Ids internally.
- </para>
-
- <para>In the session-less mode the library assumes that the client is identified on the server and the session Ids are not managed directly. This way of operation requires more sophisticated pazpar2 proxy (preferably a wrapper written in a server-side scripting language like PHP that can identify clients and relate them to open pazpar2 sessions).</para>
-
- <para><bridgehead>Using pz2.js</bridgehead></para>
-
- <para>
- Client development with the pz2.js is strongly event based and the style should be familiar to most JavaScript developers. A simple client (jsdemo) is distributed with pazpar2's source code and shows how to set-up and use pz2.js.
- </para>
-
- <para>
- In short, programmer starts by instantiating the pz2 object and passing an array of parameters to the constructor. The parameter array specifies callbacks used for handling responses to the pazpar2 commands. Additionally, the parameter array is used to configure run-time parameters of the pz2.js like polling timer time-outs, session-mode and XSLT style-sheets.
- </para>
-
- <para><bridgehead>Command callbacks</bridgehead></para>
-
- <para>
- Callback naming is simple and follows “on” prefix plus command name scheme (like onsearch, onshow, onrecord, ... etc.). When programmer calls a function like show or record on the pz2 object, pz2.js will keep on polling pazpar2 (until the backend targets are idle) and with each command's response an assigned callback will be called. In case of pazpar2's internal error an error callback is called.
- </para>
-
- <screen>
- my_paz = new pz2 (
+ <title>Ajax client development</title>
+ <para>
+ Pazpar2 offers programmer a simple Web Service protocol that can be
+ used (queried in a request/response fashion) from any, server- or
+ client-side, programming language with an XML support. However, when
+ programming a Web-based client to Pazpar2, to achieve certain level of
+ interactivity and instant notification of latest changes in the result
+ set, Ajax (Asynchronous JavaScript and XML) technology may be used. An
+ Ajax client allows user to browse the results before the lengthy
+ process of information retrieval from the back-end targets is
+ finished. Blocking and waiting for usually slow back-end targets is
+ one of the biggest functionality issues in a federated search engine.
+ </para>
+ <para>
+ Pazpar2 comes with a small JavaScript library called
+ <filename>pz2.js</filename>.
+ This library is designed to simplify development of an Ajax-based pazpar2
+ client and alleviate programmer from the low-level details like
+ polling the web service, fetching and parsing returned XML output or
+ managing timers, sessions and basic state variables.
+ </para>
+ <para>
+ The library supports most major browsers including Firefox 1.5+, IE
+ 6+, Safari 2+, Opera 9+ and Konqueror.
+ </para>
+ <para>
+ The library can work in two modes: a session-aware mode and a
+ session-less mode.
+ </para>
+ <para>
+ In the session-aware mode, the library assumes that the pazpar2
+ daemon is contacted directly (preferably via Apache proxy to avoid
+ security breaches) and tracks the session Ids internally.
+ </para>
+ <para>
+ In the session-less mode the library assumes that the client is
+ identified on the server and the session Ids are not managed
+ directly. This way of operation requires more sophisticated pazpar2
+ proxy (preferably a wrapper written in a server-side scripting
+ language like PHP that can identify clients and relate them to open
+ pazpar2 sessions).
+ </para>
+ <para><bridgehead>Using <filename>pz2.js</filename></bridgehead></para>
+ <para>
+ Client development with the <filename>pz2.js</filename> is strongly event based and the
+ style should be familiar to most JavaScript developers. A simple
+ client (jsdemo) is distributed with pazpar2's source code and shows
+ how to set-up and use <filename>pz2.js</filename>.
+ </para>
+ <para>
+ In short, programmer starts by instantiating the pz2 object and
+ passing an array of parameters to the constructor. The parameter array
+ specifies callbacks used for handling responses to the pazpar2
+ commands. Additionally, the parameter array is used to configure
+ run-time parameters of the <filename>pz2.js</filename> like polling
+ timer time-outs, session-mode and XSLT style-sheets.
+ </para>
+ <para><bridgehead>Command callbacks</bridgehead></para>
+ <para>
+ Callback naming is simple and follows “on” prefix plus command name
+ scheme (like onsearch, onshow, onrecord, ... etc.). When programmer
+ calls a function like show or record on the pz2 object, <filename>pz2.js</filename> will
+ keep on polling pazpar2 (until the backend targets are idle) and with
+ each command's response an assigned callback will be called. In case
+ of pazpar2's internal error an error callback is called.
+ </para>
+ <screen>
+ my_paz = new pz2 (
{
- "pazpar2path": "/pazpar2/search.pz2",
- "usesessions" : true,
-
- // assigning command handler, turns on automatic polling
- "onshow": my_onshow,
- // polling period for each command can be specified
- "showtime": 500,
-
- "onterm": my_onterm,
- // facet terms are specified as a comma separated list
- "termlist": "subject,author",
-
- "onrecord": my_onrecord
- }
+ "pazpar2path": "/pazpar2/search.pz2",
+ "usesessions" : true,
+
+ // assigning command handler, turns on automatic polling
+ "onshow": my_onshow,
+ // polling period for each command can be specified
+ "showtime": 500,
+
+ "onterm": my_onterm,
+ // facet terms are specified as a comma separated list
+ "termlist": "subject,author",
+
+ "onrecord": my_onrecord
+ }
);
- </screen>
-
- <para>
- Each command callback is a user defined function that takes a hash object as a parameter. The hash object contains parsed pazpar2 responses (hash members that correspond to the elements in the response XML document). Within the handler programmer further processes the data and updates the viewed document.
- </para>
-
- <screen>
- function my_onstat(data) {
- var stat = document.getElementById("stat");
- stat.innerHTML = '<span>Active clients: '+ data.activeclients
- + '/' + data.clients + ' | </span>'
- + '<span>Retrieved records: ' + data.records
- + '/' + data.hits + '</span>';
- }
-
- function my_onshow(data) {
- // data contains parsed show response
- for (var i = 0; i < data.hits[0].length; i++)
- // update page with the hits
- }
-
- function on_record(data) {
- // if detailsstylesheet parameter was set data array
- // will contain raw xml and xsl data
- Element_appendTransformResult(someDiv, data.xmlDoc, data.xslDoc);
- }
- </screen>
-
- <para><bridgehead>pz2.js on runtime</bridgehead></para>
-
- <para>
- The search process is initiated by calling the search method on the instantiated pz2 object. To initiate short status reports and per-target status information methods stat and bytarget have to be called accordingly.
- </para>
-
- <screen>
- my_paz.search (query, recPergPage, 'relevance');
- </screen>
-
- <para>
- Managing the results (keeping track of the browsed results page and sorting) is up to the client's programmer. At any point the show method may be called to bring up the latest result set with a different sorting criteria or range and without re-executing the search on the back-end.
- </para>
-
- <screen>
- my_paz.show (1, 10, 'relevance');
- </screen>
-
- <para>
- To retrieve a detailed record the record command is called. When calling record command one may temporarily override its default callback by specifying the handler parameter. This might be useful when retrieving raw records that need to be processed differently.
- </para>
-
- <screen>
- my_paz.record (recId, 2, 'opac', { “callback”: temp_callback, “args”, caller_args});
- </screen>
-
- <variablelist>
-
- <para><bridgehead>PARAMATERS ARRAY</bridgehead></para>
-
- <varlistentry><term>pazpar2path</term>
- <listitem><para>server path to pazpar2 (relative to the portal), when pazpar2 is installed as a package this does not have to be set </para></listitem>
- </varlistentry>
-
- <varlistentry><term>usesessions</term>
- <listitem><para>boolean, when set to true pz2.js will manage sessions internally otherwise it's left to the server-side script, default true</para></listitem>
- </varlistentry>
-
- <varlistentry><term>autoInit</term>
- <listitem><para>bolean, sets auto initialization of pazpar2 session on the object instantiation, default true, valid only if usesession is set to true</para></listitem>
- </varlistentry>
-
- <varlistentry><term>detailstylesheet</term>
- <listitem><para>path to the xsl presentation stylesheet (relative to the portal) used for the detailed record display</para></listitem></varlistentry>
-
- <varlistentry><term>errorhandler</term>
- <listitem><para>callback function called on any, pazpar2 or pz2.js' internal, error</para></listitem></varlistentry>
-
- <varlistentry><term>oninit</term>
- <listitem><para>specifies init response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onstat</term>
- <listitem><para>specifies stat response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onshow</term>
- <listitem><para>specifies show response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onterm</term>
- <listitem><para>specifies termlist response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onrecord</term>
- <listitem><para>specifies record response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onbytarget</term>
- <listitem><para>specifies bytarget response callback function</para></listitem></varlistentry>
-
- <varlistentry><term>onreset</term>
- <listitem><para>specifies reset method callback function</para></listitem></varlistentry>
-
- <varlistentry><term>termlist</term>
- <listitem><para>comma separated list of facets</para></listitem></varlistentry>
-
- <varlistentry><term>keepAlive</term>
- <listitem><para>ping period, should not be lower than 5000 usec</para></listitem></varlistentry>
+ </screen>
+ <para>
+ Each command callback is a user defined function that takes a hash
+ object as a parameter. The hash object contains parsed pazpar2
+ responses (hash members that correspond to the elements in the
+ response XML document). Within the handler programmer further
+ processes the data and updates the viewed document.
+ </para>
+ <screen>
+ function my_onstat(data) {
+ var stat = document.getElementById("stat");
+ stat.innerHTML = '<span>Active clients: '+ data.activeclients
+ + '/' + data.clients + ' | </span>'
+ + '<span>Retrieved records: ' + data.records
+ + '/' + data.hits + '</span>';
+ }
+
+ function my_onshow(data) {
+ // data contains parsed show response
+ for (var i = 0; i < data.hits[0].length; i++)
+ // update page with the hits
+ }
+
+ function on_record(data) {
+ // if detailsstylesheet parameter was set data array
+ // will contain raw xml and xsl data
+ Element_appendTransformResult(someDiv, data.xmlDoc, data.xslDoc);
+ }
+ </screen>
+ <para><bridgehead><filename>pz2.js</filename> on runtime</bridgehead></para>
+ <para>
+ The search process is initiated by calling the search method on the
+ instantiated pz2 object. To initiate short status reports and
+ per-target status information methods stat and bytarget have to be
+ called accordingly.
+ </para>
+ <screen>
+ my_paz.search (query, recPergPage, 'relevance');
+ </screen>
+ <para>
+ Managing the results (keeping track of the browsed results page and
+ sorting) is up to the client's programmer. At any point the show
+ method may be called to bring up the latest result set with a
+ different sorting criteria or range and without re-executing the
+ search on the back-end.
+ </para>
+ <screen>
+ my_paz.show (1, 10, 'relevance');
+ </screen>
+ <para>
+ To retrieve a detailed record the record command is called. When
+ calling record command one may temporarily override its default
+ callback by specifying the handler parameter. This might be useful
+ when retrieving raw records that need to be processed differently.
+ </para>
+ <screen>
+ my_paz.record (recId, 2, 'opac', { “callback”: temp_callback, “args”, caller_args});
+ </screen>
+ <variablelist>
+ <para><bridgehead>PARAMETERS ARRAY</bridgehead></para>
+ <varlistentry><term>pazpar2path</term>
+ <listitem><para>server path to pazpar2 (relative to the portal), when pazpar2 is installed as a package this does not have to be set </para></listitem>
+ </varlistentry>
+ <varlistentry><term>usesessions</term>
+ <listitem><para>boolean, when set to true <filename>pz2.js</filename> will manage sessions internally otherwise it's left to the server-side script, default true</para></listitem>
+ </varlistentry>
+ <varlistentry><term>autoInit</term>
+ <listitem><para>bolean, sets auto initialization of pazpar2 session on the object instantiation, default true, valid only if usesession is set to true</para></listitem>
+ </varlistentry>
+ <varlistentry><term>detailstylesheet</term>
+ <listitem><para>path to the xsl presentation stylesheet (relative to the portal) used for the detailed record display</para></listitem></varlistentry>
+
+ <varlistentry><term>errorhandler</term>
+ <listitem><para>callback function called on any, pazpar2 or <filename>pz2.js</filename>' internal, error</para></listitem></varlistentry>
+
+ <varlistentry><term>oninit</term>
+ <listitem><para>specifies init response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onstat</term>
+ <listitem><para>specifies stat response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onshow</term>
+ <listitem><para>specifies show response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onterm</term>
+ <listitem><para>specifies termlist response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onrecord</term>
+ <listitem><para>specifies record response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onbytarget</term>
+ <listitem><para>specifies bytarget response callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>onreset</term>
+ <listitem><para>specifies reset method callback function</para></listitem></varlistentry>
+
+ <varlistentry><term>termlist</term>
+ <listitem><para>comma separated list of facets</para></listitem></varlistentry>
+
+ <varlistentry><term>keepAlive</term>
+ <listitem><para>ping period, should not be lower than 5000 usec</para></listitem></varlistentry>
+
+ <varlistentry><term>stattime</term>
+ <listitem><para>default 1000 usec</para></listitem></varlistentry>
+
+ <varlistentry><term>termtime</term></varlistentry>
+
+ <varlistentry><term>showtime</term></varlistentry>
+
+ <varlistentry><term>bytargettime</term></varlistentry>
+
+ </variablelist>
- <varlistentry><term>stattime</term>
- <listitem><para>default 1000 usec</para></listitem></varlistentry>
+ <variablelist>
- <varlistentry><term>termtime</term></varlistentry>
+ <para><bridgehead>METHODS</bridgehead></para>
- <varlistentry><term>showtime</term></varlistentry>
+ <varlistentry><term>stop ()</term>
+ <listitem><para>stop activity by clearing timeouts</para></listitem></varlistentry>
- <varlistentry><term>bytargettime</term></varlistentry>
+ <varlistentry><term>reset ()</term>
+ <listitem><para>reset state</para></listitem></varlistentry>
- </variablelist>
+ <varlistentry><term>init (sessionId, serviceId)</term>
+ <listitem><para>session-mode, initialize new session or pick up a session already initialized</para></listitem></varlistentry>
- <variablelist>
-
- <para><bridgehead>METHODS</bridgehead></para>
-
- <varlistentry><term>stop ()</term>
- <listitem><para>stop activity by clearing timeouts</para></listitem></varlistentry>
+ <varlistentry><term>ping ()</term>
+ <listitem><para>session-mode, intitialize pinging </para></listitem></varlistentry>
- <varlistentry><term>reset ()</term>
- <listitem><para>reset state</para></listitem></varlistentry>
+ <varlistentry><term>search (query, num, sort, filter, showfrom)</term>
+ <listitem><para>execute piggy-back search and activate polling on every command specified by assigning command callback (in the pz2 constructor)</para></listitem></varlistentry>
- <varlistentry><term>init (sesionId)</term>
- <listitem><para>session-mode, initialize new session or pick up a session already initialized</para></listitem></varlistentry>
+ <varlistentry><term>show (start, num, sort)</term>
+ <listitem><para>start or change parameters of polling for a given window of records</para></listitem></varlistentry>
- <varlistentry><term>ping ()</term>
- <listitem><para>session-mode, intitialize pinging </para></listitem></varlistentry>
+ <varlistentry><term>record (id, offset, syntax, handler)</term>
+ <listitem><para>retrieve detailed or raw record. handler temporarily overrides default callback function.</para></listitem></varlistentry>
- <varlistentry><term>search (query, num, sort, filter, showfrom)</term>
- <listitem><para>execute piggy-back search and activate polling on every command specified by assigning command callback (in the pz2 constructor)</para></listitem></varlistentry>
+ <varlistentry><term>termlist ()</term>
+ <listitem><para>start polling for termlists</para></listitem></varlistentry>
- <varlistentry><term>show (start, num, sort)</term>
- <listitem><para>start or change parameters of polling for a given window of records</para></listitem></varlistentry>
+ <varlistentry><term>bytarget ()</term>
+ <listitem><para>start polling for target status</para></listitem></varlistentry>
- <varlistentry><term>record (id, offset, syntax, handler)</term>
- <listitem><para>retrieve detailed or raw record. handler temporarily overrides default callback function.</para></listitem></varlistentry>
+ <varlistentry><term>stat ()</term>
+ <listitem><para>start polling for pazpar2 status</para></listitem></varlistentry>
- <varlistentry><term>termlist ()</term>
- <listitem><para>start polling for termlists</para></listitem></varlistentry>
+ </variablelist>
- <varlistentry><term>bytarget ()</term>
- <listitem><para>start polling for target status</para></listitem></varlistentry>
+ <para/>
+ <para><filename>pz2.js</filename> comes with a set of cross-browser helper classes and functions.</para>
- <varlistentry><term>stat ()</term>
- <listitem><para>start polling for pazpar2 status</para></listitem></varlistentry>
+ <variablelist>
- </variablelist>
-
- <para/>
- <para>Pz2.js comes with a set of cross-browser helper classes and functions.</para>
+ <para><bridgehead>Ajax helper class</bridgehead></para>
- <variablelist>
+ <varlistentry><term>pzHttpRequest</term>
+ <listitem><para>a cross-browser Ajax wrapper class</para></listitem></varlistentry>
- <para><bridgehead>AJAX helper class</bridgehead></para>
+ <varlistentry><term>constructor (url, errorHandler)</term>
+ <listitem><para>create new request for a given url</para></listitem></varlistentry>
- <varlistentry><term>pzHttpRequest</term>
- <listitem><para>a cross-browser Ajax wrapper class</para></listitem></varlistentry>
+ <varlistentry><term>get (params, callback)</term>
+ <listitem><para>asynchronous, send the request with given parameters (array) and call callback with response as parameter</para></listitem></varlistentry>
- <varlistentry><term>constructor (url, errorHandler)</term>
- <listitem><para>create new request for a given url</para></listitem></varlistentry>
+ <varlistentry><term>post (params, data, callback)</term>
+ <listitem><para>asychronous, post arbitrary data (may be XML doc) and call callback with response as parameter</para></listitem></varlistentry>
- <varlistentry><term>get (params, callback)</term>
- <listitem><para>asynchronous, send the request with given parameters (array) and call callback with response as parameter</para></listitem></varlistentry>
+ <varlistentry><term>load ()</term>
+ <listitem><para>synchronous, returns the response for the given request</para></listitem></varlistentry>
- <varlistentry><term>post (params, data, callback)</term>
- <listitem><para>asychronous, post arbitrary data (may be XML doc) and call callback with response as parameter</para></listitem></varlistentry>
+ </variablelist>
- <varlistentry><term>load ()</term>
- <listitem><para>synchronous, returns the response for the given request</para></listitem></varlistentry>
+ <variablelist>
- </variablelist>
+ <para><bridgehead>XML helper functions</bridgehead></para>
- <variablelist>
+ <varlistentry><term>document.newXmlDoc (root)</term>
+ <listitem><para>create new XML document with root node as specified in parameter</para></listitem></varlistentry>
- <para><bridgehead>XML helper functions</bridgehead></para>
-
- <varlistentry><term>document.newXmlDoc (root)</term>
- <listitem><para>create new XML document with root node as specified in parameter</para></listitem></varlistentry>
+ <varlistentry><term>document.parseXmlFromString (xmlString)</term>
+ <listitem><para>create new XML document from string</para></listitem></varlistentry>
- <varlistentry><term>document.parseXmlFromString (xmlString)</term>
- <listitem><para>create new XML document from string</para></listitem></varlistentry>
+ <varlistentry><term>document.transformToDoc (xmlDoc, xslDoc)</term>
+ <listitem><para>returns new XML document as a result</para></listitem></varlistentry>
- <varlistentry><term>document.transformToDoc (xmlDoc, xslDoc)</term>
- <listitem><para>returns new XML document as a result</para></listitem></varlistentry>
+ <varlistentry><term>Element_removeFromDoc (DOM_Element)</term>
+ <listitem><para>remove element from the document</para></listitem></varlistentry>
- <varlistentry><term>Element_removeFromDoc (DOM_Element)</term>
- <listitem><para>remove element from the document</para></listitem></varlistentry>
+ <varlistentry><term>Element_emptyChildren (DOM_Element)</term></varlistentry>
- <varlistentry><term>Element_emptyChildren (DOM_Element)</term></varlistentry>
+ <varlistentry><term>Element_appendTransformResult (DOM_Element, xmlDoc, xslDoc)</term>
+ <listitem><para>append xsl transformation result to a DOM element</para></listitem></varlistentry>
- <varlistentry><term>Element_appendTransformResult (DOM_Element, xmlDoc, xslDoc)</term>
- <listitem><para>append xsl transformation result to a DOM element</para></listitem></varlistentry>
+ <varlistentry><term>Element_appendTextNode (DOM_Element, tagName, textContent)</term>
+ <listitem><para>append new text node to the element</para></listitem></varlistentry>
- <varlistentry><term>Element_appendTextNode (DOM_Element, tagName, textContent)</term>
- <listitem><para>append new text node to the element</para></listitem></varlistentry>
+ <varlistentry><term>Element_setTextContent (DOM_Element, textContent)</term>
+ <listitem><para>set text content of the element</para></listitem></varlistentry>
- <varlistentry><term>Element_setTextContent (DOM_Element, textContent)</term>
- <listitem><para>set text content of the element</para></listitem></varlistentry>
+ <varlistentry><term>Element_getTextContent (DOM_Element)</term>
+ <listitem><para>get text content of the element</para></listitem></varlistentry>
- <varlistentry><term>Element_getTextContent (DOM_Element)</term>
- <listitem><para>get text content of the element</para></listitem></varlistentry>
+ <varlistentry><term>Element_parseChildNodes (DOM_Element)</term>
+ <listitem><para>parse all descendants into an associative array</para></listitem></varlistentry>
- <varlistentry><term>Element_parseChildNodes (DOM_Element)</term>
- <listitem><para>parse all descendants into an associative array</para></listitem></varlistentry>
+ </variablelist>
- </variablelist>
-
</section>
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projects / pazpar2-moved-to-github.git / blobdiff