Redis+PHP秒杀设计

 1 <?php
 2 class Base{
 3     static $redisObj;
 4     /*通过单例方式初始化一个redis连接*/
 5     static function conRedis($config = array()){
 6         if(self::$redisObj) return self::$redisObj;
 7         self::$redisObj = new \Redis();
 8         self::$redisObj->connect(‘127.0.0.1‘, 6379);
 9         return self::$redisObj;
10     }
11     /*接口输出格式化*/
12     static function output($data = array(), $errNo = 0, $errMsg = ‘ok‘){
13         $res[‘errno‘] = $errNo;
14         $res[‘errmsg‘] = $errMsg;
15         $res[‘data‘] = $data;
16         echo json_encode($res);
17         exit();
18     }
19 }

  1 <?php
  2 include(‘base.php‘);
  3 class Api extends Base
  4 {
  5     //共享信息，存储在redis中,以hash表的形式存储，%s变量代表的是商品id
  6     static $userId;
  7     static $productId;
  8     static $REDIS_REMOTE_HT_KEY         = "product_%s";     //共享信息key
  9     static $REDIS_REMOTE_TOTAL_COUNT    = "total_count";    //商品总库存
 10     static $REDIS_REMOTE_USE_COUNT      = "used_count";     //已售库存
 11     static $REDIS_REMOTE_QUEUE          = "c_order_queue";  //创建订单队列
 12     static $APCU_LOCAL_STOCK    = "apcu_stock_%s";       //总共剩余库存
 13     static $APCU_LOCAL_USE      = "apcu_stock_use_%s";   //本地已售多少
 14     static $APCU_LOCAL_COUNT    = "apcu_total_count_%s"; //本地分库存分摊总数
 15     public function __construct($productId, $userId)
 16     {
 17         self::$REDIS_REMOTE_HT_KEY  = sprintf(self::$REDIS_REMOTE_HT_KEY, $productId);
 18         self::$APCU_LOCAL_STOCK     = sprintf(self::$APCU_LOCAL_STOCK, $productId);
 19         self::$APCU_LOCAL_USE       = sprintf(self::$APCU_LOCAL_USE, $productId);
 20         self::$APCU_LOCAL_COUNT     = sprintf(self::$APCU_LOCAL_COUNT, $productId);
 21         self::$APCU_LOCAL_COUNT     = sprintf(self::$APCU_LOCAL_COUNT, $productId);
 22         self::$userId               = $userId;
 23         self::$productId            = $productId;
 24     }
 25     static  function clear(){
 26     apcu_delete(self::$APCU_LOCAL_STOCK);
 27     apcu_delete(self::$APCU_LOCAL_USE);
 28     apcu_delete(self::$APCU_LOCAL_COUNT);
 29         
 30     }
 31     /*查剩余库存*/
 32     static function getStock()
 33     {
 34     $stockNum = apcu_fetch(self::$APCU_LOCAL_STOCK);
 35         if ($stockNum === false) {
 36             $stockNum = self::initStock();
 37         }
 38         self::output([‘stock_num‘ => $stockNum]);
 39     }
 40     /*抢购-减库存*/
 41     static function buy()
 42     {
 43         $localStockNum = apcu_fetch(self::$APCU_LOCAL_COUNT);
 44         if ($localStockNum === false) {
 45             $localStockNum = self::init();
 46         }
 47         $localUse = apcu_inc(self::$APCU_LOCAL_USE);//本已卖 + 1
 48         if ($localUse > $localStockNum) {//抢购失败 大部分流量在此被拦截
 49         echo 1;
 50             self::output([], -1, ‘该商品已售完‘);
 51         }
 52         //同步已售库存 + 1；
 53         if (!self::incUseCount()) {//改失败，返回商品已售完
 54             self::output([], -1, ‘该商品已售完‘);
 55         }
 56         //写入创建订单队列
 57         self::conRedis()->lPush(self::$REDIS_REMOTE_QUEUE, json_encode([‘user_id‘ => self::$userId, ‘product_id‘ => self::$productId]));
 58         //返回抢购成功
 59         self::output([], 0, ‘抢购成功，请从订单中心查看订单‘);
 60     }
 61     /*创建订单*/
 62     /*查询订单*/
 63     /*总剩余库存同步本地，定时执行就可以*/
 64     static function sync()
 65     {
 66         $data = self::conRedis()->hMGet(self::$REDIS_REMOTE_HT_KEY, [self::$REDIS_REMOTE_TOTAL_COUNT, self::$REDIS_REMOTE_USE_COUNT]);
 67         $num = $data[‘total_count‘] - $data["used_count"];
 68         apcu_add(self::$APCU_LOCAL_STOCK, $num);
 69         self::output([], 0, ‘同步库存成功‘);
 70     }
 71     /*私有方法*/
 72     //库存同步
 73     private static function incUseCount()
 74     {
 75         //需要查远端的总库存和已经售卖的计数
 76         //同步远端库存时，需要经过lua脚本，保证不会出现超卖现象
 77         //因为redis是单进程模型,可有效的避免两个用户同时进行查库存和扣库存
 78         $script = <<<eof
 79             local key = KEYS[1]
 80             local field1 = KEYS[2]
 81             local field2 = KEYS[3]
 82             local field1_val = redis.call(‘hget‘, key, field1)//总库存
 83             local field2_val = redis.call(‘hget‘, key, field2)//已经售卖的计数
 84             if(field1_val>field2_val) then
 85                 return redis.call(‘HINCRBY‘, key, field2,1)
 86             end
 87             return 0
 88 eof;
 89         //eval()执行lua脚本的方法
 90         return self::conRedis()->eval($script,[self::$REDIS_REMOTE_HT_KEY,  self::$REDIS_REMOTE_TOTAL_COUNT, self::$REDIS_REMOTE_USE_COUNT] , 3);
 91     }
 92     /*初始化本地数据*/
 93     private static function init()
 94     {
 95         apcu_add(self::$APCU_LOCAL_COUNT, 150);
 96         apcu_add(self::$APCU_LOCAL_USE, 0);
 97     }
 98     static  function initStock(){
 99         $data = self::conRedis()->hMGet(self::$REDIS_REMOTE_HT_KEY, [self::$REDIS_REMOTE_TOTAL_COUNT, self::$REDIS_REMOTE_USE_COUNT]);
100         $num = $data[‘total_count‘]- $data["used_count"];
101         apcu_add(self::$APCU_LOCAL_STOCK, $num);
102         return $num;
103     }
104 }
105 try{
106 $act = $_GET[‘act‘];
107 $product_id = $_GET[‘product_id‘];
108 $user_id = $_GET[‘user_id‘];
109 $obj = new Api($product_id, $user_id);
110 if (method_exists($obj, $act)) {
111     $obj::$act();
112     die;
113 }
114 echo ‘method_error!‘;
115 } catch (\Exception $e) {
116     echo ‘exception_error!‘;
117     var_dump($e);
118 }