Auth_OpenID_PredisStore::useNonce PHP Method

    function useNonce($server_url, $timestamp, $salt)
    {
        global $Auth_OpenID_SKEW;
        // save one request to memcache when nonce obviously expired
        if (abs($timestamp - time()) > $Auth_OpenID_SKEW) {
            return false;
        }
        // SETNX will set the value only of the key doesn't exist yet.
        $nonceKey = $this->nonceKey($server_url, $salt);
        $added = $this->redis->setnx($nonceKey, "1");
        if ($added) {
            // Will set expiration
            $this->redis->expire($nonceKey, $Auth_OpenID_SKEW);
            return true;
        } else {
            return false;
        }
    }