推荐11-PHP用redis解决超卖的问题

CREATE TABLE `ims_order` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `order_sn` char(32) NOT NULL,
  `user_id` int(11) NOT NULL,
  `status` int(11) NOT NULL DEFAULT '0',
  `goods_id` int(11) NOT NULL DEFAULT '0',
  `sku_id` int(11) NOT NULL DEFAULT '0',
  `number` int(11) NOT NULL,
  `price` int(10) NOT NULL COMMENT '价格：单位为分',
  `create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5820 DEFAULT CHARSET=utf8 COMMENT='订单表'

CREATE TABLE `ims_hotmallstore_goods` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL COMMENT '商品名称',
  `type_id` int(11) NOT NULL COMMENT '商品分类',
  `img` text NOT NULL COMMENT '商品图片',
  `money` decimal(10,2) NOT NULL COMMENT '售价',
  `money2` decimal(10,2) NOT NULL COMMENT '原价',
  `is_show` int(11) NOT NULL DEFAULT '1' COMMENT '1.上架2.下架',
  `uniacid` int(11) NOT NULL COMMENT '小程序id',
  `inventory` int(11) NOT NULL COMMENT '库存',
  `details` text NOT NULL COMMENT '详情',
  `store_id` int(11) NOT NULL COMMENT '商家id',
  `sales` int(11) NOT NULL COMMENT '销量',
  `logo` varchar(100) NOT NULL,
  `num` int(11) NOT NULL,
  `is_gg` int(11) NOT NULL DEFAULT '2' COMMENT '是否开启规格',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8

CREATE TABLE `ims_order_log` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `status` int(11) NOT NULL DEFAULT '0',
  `msg` text CHARACTER SET utf8,
  `create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `status` (`status`)
) ENGINE=InnoDB AUTO_INCREMENT=4562 DEFAULT CHARSET=gb2312 COMMENT='订单日志表'

class Test {

    private static $instance = null;

    // 用单列模式 实例化Redis
    public static function Redis()
    {
        if (self::$instance == null) {
            $redis=new \Redis();
            $redis->connect('127.0.0.1',6379);
            self::$instance = $redis;
        }
        return self::$instance;
    }

    // 将商品库存循环到lpush的num里
    public function doPageSaveNum()
    {
        $redis=self::Redis();
        $goods_id=1;
        $sql="select id, num, money from ims_hotmallstore_goods where id=".$goods_id;
        $goods=pdo_fetch($sql);
        if(!empty($goods)){
         for($i=1; $i<=$goods['num']; $i++){
             $redis->lpush('num',$i);
         }
         die('成功！');
        }else{
         $this->echoMsg(0,'商品不存在。');
        }
    }

    // 抢购下单
    public function doPageGoodsStore()
    {
            $goods_id=1;
            $sql="select id, num, money from ims_hotmallstore_goods where id=".$goods_id;
            $goods=pdo_fetch($sql);
            $redis=self::Redis();
            $count=$redis->rpop('num');//每次从num取出1
            if($count==0){
                $this->echoMsg(0,'no num redis');
            }
            $this->doPageGoodsOrder($goods,1);
            
    }

    // 保存日志
    public function echoMsg($status,$msg,$_data="")
    {
      
        $data=json_encode(array('status'=>$status,'msg'=>$msg,'data'=>$_data),JSON_UNESCAPED_UNICODE);
        $order_log['status']=$status;
        $order_log['msg']=$msg;
        $order_log['create_time']=time();
        pdo_insert('order_log',$order_log);
       die($data);
    }
    public function orderNo()
    {
        return date('ymd').substr(implode(NULL, array_map('ord', str_split(substr(uniqid(), 7, 13), 1))), 0, 8);
    }
    
    // 下单更新库存
    public function doPageGoodsOrder($goods,$goods_number)
    {
        $orderNo=$this->orderNo();
        $number=$goods['num']-$goods_number;
        if($number<0){
            $this->echoMsg(0,'已没有库存');
        }
        $user_id=rand(1,500);
        $order['user_id']=$user_id;
        $order['goods_id']=$goods['id'];
        $order['number']=$goods_number;
        $order['price']=$goods['money'];
        $order['status']=1;
        $order['sku_id']=2;
        $order['order_sn']=$orderNo;
        $order['create_time']=date('Y-m-d H:i:s');
        pdo_insert('order',$order);
        $sql="update ims_hotmallstore_goods set num=num-".$goods_number." where num>0 and id=".$goods['id'];
        $res=pdo_query($sql);
        if(!empty($res)){
            $this->echoMsg(1,'库存扣减成功'.$number);
        }
        $redis=self::Redis();
        $redis->lpush('num',$goods_number);
        $this->echoMsg(0,'库存扣减失败'.$number);

    }
 }

// 调用--将商品库存循环到lpush的num里
if($_GET['i']==1){
   $model = new Test;
   $model->doPageSaveNum();
}

// 调用--高并发抢购下单
if($_GET['i']==2){
   $model = new Test;
   $model->doPageGoodsStore();
}