<?
class CacheHandler
{
    protected $redis;

    public function __construct()
    {
        if (class_exists('Redis')) {
            try {
                $this->redis = \RedisConnection::getInstance()->getConnection();
            } catch (\Exception $e) {
                $this->redis = null;
            }
        }
    }

    public function get($key)
    {
        if ($this->redis) {
            return $this->redis->get($key);
        }
        return null;
    }

    public function set($key, $value, $ttl = 86400) // 86400 = 60 * 60 * 24 (1 dzień)
    {
        if ($this->redis) {
            $this->redis->setex($key, $ttl, serialize($value));
        }
    }

    public function exists($key)
    {
        if ($this->redis) {
            return $this->redis->exists($key);
        }
        return false;
    }
}