Controller\Invite::buy PHP Method

    public function buy()
    {
        $user = User::getUserByUserId(User::getCurrent()->uid);
        $result = array('error' => 1, 'message' => '购买失败，至少需要20GB流量才能购买邀请码。');
        $transfer = Utils::GB * 10;
        // update by github.com/BorLee
        // 1abd9e6be7bfd7e3b1e9f34acd357fa7fa29923c
        if ($user->transfer > $transfer * 2 && $user->transfer - $user->getUseTransfer() > $transfer) {
            $user->transfer = $user->transfer - $transfer;
            $user->invite_num = $user->invite_num + 1;
            $user->save();
            $result = array('error' => 0, 'message' => '购买成功，扣除手续费10GB流量', 'invite_num' => $user->invite_num);
        }
        return $result;
    }