php + redis 实现秒杀

一、概述

秒杀这个问题在很多面试的时候都会提到，会有各个方面的调优，配置等等，本文在这里举个简单的例子来演示下秒杀的过程，供大家参考发散思维。

二、准备介绍

thinkPHP6框架
redis6.0
php7.4
redis操作包predis
apache-jmeter-5.6

三、代码实现

秒杀controller层的简易代码：

<?php
/**
 * Created by PhpStorm
 * Author: fengzi
 * Date: 2024/4/8
 * Time: 10:07
 */

namespace app\admin\controller\seckill;

use app\admin\service\seckill\SeckillService;

class SeckillController
{
    public function __construct()
    {
    }

    /**
     * 设置商品数量
     * @param SeckillService $seckillService
     * @return \think\response\Json
     * @Author: fengzi
     * @Date: 2024/4/8 10:00
     */
    public function setNumber(SeckillService $seckillService)
    {
        $seckillService->setProductNumber();

        try {
            $seckillService->setProductNumber();

            return success('设置成功');
        } catch (\Exception $e) {
            return error($e->getMessage());
        }
    }

    /**
     * 购买入口
     * @param SeckillService $seckillService
     * @return \think\response\Json
     * @Author: fengzi
     * @Date: 2024/4/8 11:00
     */
    public function index(SeckillService $seckillService)
    {
        try {
            $seckillService->seckill();

            return success();
        } catch (\Exception $e) {
            return error($e->getMessage());
        }
    }

}

秒杀service层的简易代码：

<?php
/**
 * Created by PhpStorm
 * Author: fengzi
 * Date: 2024/4/8
 * Time: 10:09
 */

namespace app\admin\service\seckill;

use Predis\Client;

class SeckillService
{
    private Client $redisService;

    public function __construct()
    {
        // 初始化Redis连接
        $this->redisService = new Client(config('cache.stores.redis'));
    }

    /**
     * 设置秒杀的产品数量
     * @return void
     * @Author: fengzi
     * @Date: 2024/4/8 10:11
     */
    public function setProductNumber()
    {
        $this->redisService->set('product_number', 20);
    }

    /**
     * 实现秒杀过程
     * 一个用户只能购买一次商品
     * @return void
     * @Author: fengzi
     * @Date: 2024/4/8 16:45
     */
    public function seckill()
    {
        //lua脚本，保证原子性
        $lua_script = <<<LUA
local number = redis.call('get', KEYS[1])
if (redis.call('exists', KEYS[1]) == 1 and tonumber(number) > 0 ) then
    redis.call('decr', KEYS[1])
    redis.call('sadd', KEYS[2], ARGV[1])
    return true
else
    return false
end
LUA;
        //模拟用户ID
        $userId = mt_rand(1, 50);
        //抢购成功的用户列表
        $userLists = 'user_lists_id';
        try {
            $res = $this->redisService->sismember($userLists, $userId);
            if ( $res == 0 ) {
                $result = $this->redisService->eval($lua_script, 2, 'product_number', 'user_lists_id', $userId);
                if ($result) {
                    // 处理订单逻辑
                    echo "秒杀成功！！！！";
                } else {
                    echo "秒杀结束！";
                }
            } else {
                echo "秒杀失败，用户{$userId}已经秒杀过了！";
            }
        } catch (\Exception $e) {
            echo "秒杀失败：" . $e->getMessage();
        }
    }
}

接口路由：

<?php
use think\facade\Route;


/**秒杀*/
Route::group('/seckill', function () {
    //设置秒杀数量
    Route::any('set_number', '/seckill.Seckill/setNumber');
    //购买
    Route::any('index', '/seckill.Seckill/index');
});