MatthiasMullie\Scrapbook\Adapters\Redis::add PHP Method

    public function add($key, $value, $expire = 0)
    {
        $ttl = $this->ttl($expire);
        /*
         * Negative ttl behavior isn't properly documented & doesn't always
         * appear to treat the value as non-existing. Let's play safe and not
         * even create the value (also saving a request)
         */
        if ($ttl < 0) {
            return true;
        }
        if ($ttl === null) {
            return $this->client->setnx($key, $value);
        }
        /*
         * I could use Redis 2.6.12-style options array:
         * $this->client->set($key, $value, array('xx', 'ex' => $ttl));
         * However, this one should be pretty fast already, compared to the
         * replace-workaround below.
         */
        $this->client->multi();
        $this->client->setnx($key, $value);
        $this->client->expire($key, $ttl);
        /** @var bool[] $return */
        $return = (array) $this->client->exec();
        return !in_array(false, $return);
    }