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Creating a search plugin

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Revision as of 15:28, 26 August 2013 by Wilsonge (Talk | contribs)

Contents

Description

This document is about how to create a Search Plugin. You can use a Search Plugin to search through the database of your Joomla! site. To create a plugin, you will at least need two files; an XML file and a PHP file. For internationalization it is good to create an INI file as well.

XML file

The XML file is named the same as the PHP file, and is one of the two required files. Always start off with the XML tag and define that it is written in a UTF-8 format.

<?xml version="1.0" encoding="utf-8"?>

To define that the plugin has to be a search plugin, add this line

<extension version="2.5" type="plugin" group="search">

The type will define it is a plugin, the group defines the Plugin is in the group of search plugins.

After that, add some information about yourself and the plugin:

<name>Name of your search plugin</name>
<creationDate>Creation date</creationDate>
<author>Your name</author>
<authorEmail>Your e-mail address</authorEmail>
<authorUrl>Your website</authorUrl>
<copyright>Copyright information</copyright>
<license>License, for example GNU/GPL</license>
<version>Version of the plugin</version>
<description>Description of the plugin; shown during installation and when editing 
the plugin in the Plugin Manager</description>

And now, include your PHP file to the Search Plugin. The name of this file should be the same as the name of this XML file. Put this name also behind the plugin="" part.

You could also add more files for your plugin, for example, an image. Just add another row between <files> and </file>, and then place the file between <filename> tags.

<files>
   <filename plugin="nameofplugin">nameofplugin.php</filename>
</files>

For the internationalization, we will use language files. This is not required, but people from other countries will love it they can easily translate your plugin to their own language. The language tags can be found here: [1] (use the ISO 639-1 column) and here: [2]

<languages>
   <language tag="en-GB">language/en-GB/en-GB.plg_search_nameofplugin.ini</language>
</languages>

Optionally, you could add some parameters to the plugin. These will look like this

        <config>
                <fields name="params">
 
                        <fieldset name="basic">
                                <field name="search_limit" type="text"
                                        default="50"
                                        description="JFIELD_PLG_SEARCH_SEARCHLIMIT_DESC"
                                        label="JFIELD_PLG_SEARCH_SEARCHLIMIT_LABEL"
                                        size="5"
                                />
 
                                <field name="search_content" type="radio"
                                        default="0"
                                        description="JFIELD_PLG_SEARCH_ALL_DESC"
                                        label="JFIELD_PLG_SEARCH_ALL_LABEL"
                                >
                                        <option value="0">JOFF</option>
                                        <option value="1">JON</option>
                                </field>
 
                        </fieldset>
                </fields>
        </config>

Do not forget to end your XML file with the following tag

</extension>

PHP file

The PHP file of your plugin is the most important file of the plugin. This is an example PHP file of a search plugin. The comments are included.

<?php
//First start with information about the Plugin and yourself. For example:
/**
 * @package     Joomla.Plugin
 * @subpackage  Search.nameofplugin
 *
 * @copyright   Copyright
 * @license     License, for example GNU/GPL
 */
 
//To prevent accessing the document directly, enter this code:
// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' );
 
// Require the component's router file (Replace 'nameofcomponent' with the component your providing the search for
require_once JPATH_SITE .  '/components/nameofcomponent/helpers/route.php';
 
/**
 * Constructor
 *
 * @access      protected
 * @param       object  $subject The object to observe
 * @param       array   $config  An array that holds the plugin configuration
 * @since       1.6
 */
public function __construct(& $subject, $config)
{
        parent::__construct($subject, $config);
        $this->loadLanguage();
}
 
// Define a function to return an array of search areas. Replace 'nameofplugin' with the name of your plugin.
// Note the value of the array key is normally a language string
function onContentSearchAreas()
{
        static $areas = array(
                'nameofplugin' => 'Nameofplugin'
        );
        return $areas;
}
 
// The real function has to be created. The database connection should be made. 
// The function will be closed with an } at the end of the file.
/**
 * The sql must return the following fields that are used in a common display
 * routine: href, title, section, created, text, browsernav
 *
 * @param string Target search string
 * @param string mathcing option, exact|any|all
 * @param string ordering option, newest|oldest|popular|alpha|category
 * @param mixed An array if the search it to be restricted to areas, null if search all
 */
function onContentSearch( $text, $phrase='', $ordering='', $areas=null )
{
        $db             = JFactory::getDBO();
        $user   = JFactory::getUser(); 
        $app    = JFactory::getApplication();
        $groups = implode(',', $user->getAuthorisedViewLevels());
 
// If the array is not correct, return it:
        if (is_array( $areas )) {
                if (!array_intersect( $areas, array_keys( $this->onContentSearchAreas() ) )) {
                        return array();
                }
        }
 
//Define the parameters. First get the right plugin; 'search' (the group), 'nameofplugin'. 
$plugin = JPluginHelper::getPlugin('search', 'nameofplugin');
 
//Then load the parameters of the plugin.
$pluginParams = new JParameter( $plugin->params );
 
//Now define the parameters like this:
$limit = $this->params->get('nameofparameter', defaultsetting );
 
//Use the function trim to delete spaces in front of or at the back of the searching terms
$text = trim( $text );
 
//Return Array when nothing was filled in.
if ($text == '') {
                return array();
        }
 
//After this, you have to add the database part. This will be the most difficult part, because this changes per situation.
//In the coding examples later on you will find some of the examples used by Joomla! 2.5 core Search Plugins.
//It will look something like this.
        $wheres = array();
        switch ($phrase) {
 
//search exact
                case 'exact':
                        $text           = $db->Quote( '%'.$db->escape( $text, true ).'%', false );
                        $wheres2        = array();
                        $wheres2[]      = 'LOWER(a.name) LIKE '.$text;
                        $where          = '(' . implode( ') OR (', $wheres2 ) . ')';
                        break;
 
//search all or any
                case 'all':
                case 'any':
 
//set default
                default:
                        $words  = explode( ' ', $text );
                        $wheres = array();
                        foreach ($words as $word)
                        {
                                $word           = $db->Quote( '%'.$db->escape( $word, true ).'%', false );
                                $wheres2        = array();
                                $wheres2[]      = 'LOWER(a.name) LIKE '.$word;
                                $wheres[]       = implode( ' OR ', $wheres2 );
                        }
                        $where = '(' . implode( ($phrase == 'all' ? ') AND (' : ') OR ('), $wheres ) . ')';
                        break;
        }
 
//ordering of the results
        switch ( $ordering ) {
 
//alphabetic, ascending
                case 'alpha':
                        $order = 'a.name ASC';
                        break;
 
//oldest first
                case 'oldest':
 
//popular first
                case 'popular':
 
//newest first
                case 'newest':
 
//default setting: alphabetic, ascending
                default:
                        $order = 'a.name ASC';
        }
 
// Replace nameofplugin
        $section = JText::_( 'Nameofplugin' );
 
// The database query; differs per situation! It will look something like this (example from newsfeed search plugin):
$query  = $db->getQuery(true);
$query->select('a.name AS title, "" AS created, a.link AS text, ' . $case_when."," . $case_when1);
                        $query->select($query->concatenate(array($db->Quote($section), 'c.title'), " / ").' AS section');
                        $query->select('"1" AS browsernav');
                        $query->from('#__nameofcomponent AS a');
                        $query->innerJoin('#__categories as c ON c.id = a.catid');
                        $query->where('('. $where .')' . 'AND a.published IN ('.implode(',', $state).') AND c.published = 1 AND c.access IN ('. $groups .')');
                        $query->order($order);
 
// Set query
        $db->setQuery( $query, 0, $limit );
        $rows = $db->loadObjectList();
 
// The 'output' of the displayed link. Again a demonstration from the newsfeed search plugin
        foreach($rows as $key => $row) {
                $rows[$key]->href = 'index.php?option=com_newsfeeds&view=newsfeed&catid='.$row->catslug.'&id='.$row->slug;
        }
 
//Return the search results in an array
return $rows;
}

There are four variables that get passed in. They are evident by their names and use in the above code. What's not obvious is what the function should return: an array of objects that the search tool uses to display the results. The results could alternatively have been assembled like this.

$rows[] = (object) array(
                        'href'        => 'index.php?option=com_newsfeeds&view=newsfeed&catid='.$row->catslug.'&id='.$row->slug,
                        'title'       => $row['name'],
                        'section'     => $nameofcomponent,
                        'created'     => $row['date'],
                        'text'        => $row['name'],
                        'browsernav'  => '1'
                );

INI file(s)

For internationalization it is good to use the INI files. You can add everything to the language file that outputs text to the user, in this order:

  • XML description tag
  • XML label and description attributes from parameters
  • JText::_( 'string' ) used by the plugin

Start your INI file with something like this:

# $Id: en-GB.plg_search_nameofplugin.ini
# Joomla! Project
# Copyright (C) 2005 - 2007 Open Source Matters. All rights reserved.
# License http://www.gnu.org/licenses/gpl-2.0.html GNU/GPL, see LICENSE.php
# Note : All ini files need to be saved as UTF-8 - No BOM

Of course, you could also add other information, like the author.

For example, this parameter:

<field name="search_limit" type="text"
  default="50"
  description="JFIELD_PLG_SEARCH_SEARCHLIMIT_DESC"
  label="JFIELD_PLG_SEARCH_SEARCHLIMIT_LABEL"
  size="5"
/>

Will cause the following output in the INI file:

JFIELD_PLG_SEARCH_SEARCHLIMIT_DESC=Search Limit
JFIELD_PLG_SEARCH_SEARCHLIMIT_LABEL=Number of Search items to return

The file looks repetitive, but will be very useful for translators.

When you want to make your search plugin available in more languages, first add them to the