gridstatestorage.php

См. документацию.

<?php
 
namespace Bitrix\Catalog\Component\GridVariation;
 
use Bitrix\Main\Application;

class GridStateStorage
{
    private const FIELD_CURRENT_PAGE = 'currentPage';
    private const FIELD_DEADLINE = 'deadline';
 
    private const DEADLINE_SEC = 60;

    private function getStorageKey(int $productId, string $gridId): string
    {
        return "{$productId}_{$gridId}";
    }

    public function load(int $productId, string $gridId): GridState
    {
        $state = new GridState($productId, $gridId);
        $key = $this->getStorageKey($productId, $gridId);
        $cache = Application::getInstance()->getLocalSession($key);
 
        // postponed every minute so that the pages do not stick forever.
        $deadline = (int)$cache->get(self::FIELD_DEADLINE);
        if ($deadline < time())
        {
            $cache->set(self::FIELD_DEADLINE, time() + self::DEADLINE_SEC);
        }
        else
        {
            $currentPage = $cache->get(self::FIELD_CURRENT_PAGE);
            if (isset($currentPage))
            {
                $state->setCurrentPage((int)$currentPage);
            }
        }
 
        return $state;
    }

    public function save(GridState $state): void
    {
        $key = $this->getStorageKey($state->getProductId(), $state->getGridId());
        $cache = Application::getInstance()->getLocalSession($key);
        $cache->set(self::FIELD_CURRENT_PAGE, $state->getCurrentPage());
        $cache->set(self::FIELD_DEADLINE, time() + self::DEADLINE_SEC);
    }
}