search.php

См. документацию.

<?php
namespace Bitrix\Catalog\Product;
 
use Bitrix\Catalog,
    Bitrix\Iblock;

class Search
{
    protected static $catalogList = array();
    
    public static function onBeforeIndex($fields)
    {
        if (!isset($fields['MODULE_ID']) || $fields['MODULE_ID'] != 'iblock')
            return $fields;
        if (empty($fields['PARAM2']))
            return $fields;
 
        if (!isset(self::$catalogList[$fields['PARAM2']]))
        {
            self::$catalogList[$fields['PARAM2']] = false;
            $catalog = Catalog\CatalogIblockTable::getList(array(
                'select' => array('IBLOCK_ID'),
                'filter' => array('=IBLOCK_ID' => $fields['PARAM2'])
            ))->fetch();
            if (!empty($catalog))
                self::$catalogList[$fields['PARAM2']] = $catalog['IBLOCK_ID'];
            unset($catalog);
        }
 
        if (!empty(self::$catalogList[$fields['PARAM2']]) && isset($fields['ITEM_ID']))
        {
            $fields['PARAMS']['iblock_section'] = array();
            if (mb_strpos($fields['ITEM_ID'], 'S') === false)
            {
                $sections = Iblock\SectionElementTable::getList(array(
                    'select' => array('IBLOCK_SECTION_ID'),
                    'filter' => array('=IBLOCK_ELEMENT_ID' => $fields['ITEM_ID'], '=ADDITIONAL_PROPERTY_ID' => null)
                ));
                while ($section = $sections->fetch())
                {
                    $nav = \CIBlockSection::getNavChain($fields['PARAM2'], $section['IBLOCK_SECTION_ID'], array('ID'));
                    while ($chain = $nav->fetch())
                        $fields['PARAMS']['iblock_section'][$chain['ID']] = $chain['ID'];
                    unset($chain, $nav);
                }
                unset($section, $sections);
            }
            else
            {
                $nav = \CIBlockSection::getNavChain($fields['PARAM2'], preg_replace('#[^0-9]+#', '', $fields["ITEM_ID"]), array('ID'));
                while ($chain = $nav->fetch())
                    $fields['PARAMS']['iblock_section'][$chain['ID']] = $chain['ID'];
                unset($chain, $nav);
            }
            if (!empty($fields['PARAMS']['iblock_section']))
                $fields['PARAMS']['iblock_section'] = array_values($fields['PARAMS']['iblock_section']);
        }
        return $fields;
    }
}