Laravel8.5+微信小程序实现京东商城秒杀方案

一、商品秒杀涉及的知识点

• 鉴权策略封装
• 掊口访问频次限制
• 小程序设计
• 页面防抖
• 接口调用
• 订单创建事务使用
• 超卖防御

二、订单库存系统方案（3种）

1. 下单减库存 优点是库存和订单的强一致性，商品不会卖超，但是可能导致恶意下单，影响正常流程
2. 支付减库存 优点是避免恶意下单，支付和库存强一致性，但是可能出现订单无法支付，商品库存不足等问题。
3. 预扣库存 预扣库存是指用户请求之后预扣库存，生成订单，在时效内支付，否则订单失效，库存还原
4. 代码：itshujia.com 或者wx搜：《IT书架》 回复：秒杀

三、小程序秒杀页面

• 商品秒杀详情页面页面
• 该商品秒杀时间未到，则上方进行提醒秒杀商品倒计时，并且立即抢购禁用（按钮置灰）

• 商品秒杀时间开始，则把立即秒杀按钮禁用状态改为可以点击
• 点击立即秒杀按钮要考虑页面防抖，不能重复在同一秒中重复发起N次网络请求
  

四、小程序部分代码展示

1. 小程序wxml代码

<view>商品秒杀页面</view>
<l-countdown time-type="second" time="{{expire_time}}" bind:linend="changeBtn" />
<l-card type="primary" full="{{true}}" image="{{goods.goods.goods_image}}" title="{{goods.goods.goods_name}}"><view>价格：{{goods.goods.goods_price}}</view><view><!-- <button disabled="true" bindtap="buyGoods" >抢购</button> --><l-button disabled="{{ btn_disable }}" bind:lintap="buyGoods" type="error" data-goods_id="{{ goods.goods.id }}">立即秒杀</l-button></view></l-card>

2. 小程序js代码

// pages/goods_detail/goods_detail.js
import {debounce
} from "../../utils/util"Page({/*** 页面的初始数据*/data: {goods:{},expire_time:0,btn_disable:false},/*** 生命周期函数--监听页面加载*/onLoad: function (e) {//商品idlet goods_id = e.goods_id;this.getGoodsDetail(goods_id)},//获取商品详情getGoodsDetail(goods_id){var token = wx.getStorageSync('token')wx.request({url: 'http://www.zfw.com/api/v1/goods_detail?goods_id='+goods_id,header: {'Authorization': `Bearer ${token}`},success: res => {//当前的时间戳let now_time = Math.round(new Date().getTime() / 1000).toString();let expire_time = res.data.data.start_time-now_time;this.setData({goods:res.data.data,expire_time})if(expire_time > 0){this.setData({btn_disable:true})}console.log(this.data.goods)}})},//立即抢购   debounce此方法是引入的util工具类的页面防抖函数buyGoods:debounce(function (e) {let goods_id = e[0].currentTarget.dataset.goods_idvar token = wx.getStorageSync('token')wx.request({url: 'http://www.zfw.com/api/v1/snap_up',header: {'Authorization': `Bearer ${token}`},method:"POST",data:{goods_id},success: res => {let code = res.statusCode.toString()if (!code.startsWith('2')){wx.showToast({title: '异常！',icon:1})}if(res.data.errorCode == 0){wx.redirectTo({url: '/pages/order/order',})}else{wx.showToast({title: res.data.msg,})}console.log(res.data)}})}),changeBtn(){this.setData({btn_disable:false})}
})

3. 小程序json代码，引入的自定义组件

{"usingComponents": {"l-card":"/miniprogram_npm/lin-ui/card","l-button":"/miniprogram_npm/lin-ui/button","l-countdown":"/miniprogram_npm/lin-ui/countdown"}
}

五、后台业务逻辑

要考虑订单超卖，这次代码使用的redis队列实现的

<?phpnamespace App\Http\Controllers\Api;use App\Http\Controllers\Controller;
use App\Models\Goods;
use Illuminate\Http\Request;
use App\Models\ActivityGoods;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Redis;
use Lcobucci\JWT\Exception;class GoodsController extends Controller
{//商品秒杀列表public function activityList(){$result = ActivityGoods::with(['goods'])->get();return response()->json(['errorCode' => 0, 'data' => $result, 'msg' => '查询成功']);}//商品秒杀列表public function goodsDetail(Request $request){$goods_id = $request->get('goods_id');$result = ActivityGoods::with(['goods'])->where('goods_id',$goods_id)->first();return response()->json(['errorCode' => 0, 'data' => $result, 'msg' => '查询成功']);}//同步库存public function syncStock(){//查出所有参与秒杀活动列表$result = ActivityGoods::with(['goods'])->get()->toArray();//进行把参与秒杀的商品写入到数据库foreach ($result as $val){//生成对应商品库存队列$goods = "activity_goods_".$val['goods_id'];for ($i=0; $i < $val['sku_nums']; $i++) {Redis::lpush($goods, 1);}}}//校验库存public function checkStock(Request $request){//获取token$token = explode(' ',$request->header('authorization'))[1];//进行查看$userInfo = Cache::get($token);//抢购用户id$userID = $userInfo->id;//商品id$goodsID = $request->input("goods_id");//对应商品库存队列$goods = "activity_goods_".$goodsID;//对应商品抢购成功用户集合 {1,3,4}$robSuccessUser = "success_user".$goodsID;//进行判断当前用户是否在抢成功的队列里面$result = Redis::sismember($robSuccessUser,$userID);//如果你在这里面，就抢完了if ($result) {//如果抢购成功 返回状态码，进行下单return response()->json(['errorCode' => 20000, 'data' => '', 'msg' => '已经抢购过了']);}//减库存，把队列里面的数据从左边 头$count = Redis::lpop($goods);if (!$count) {//如果抢购成功 返回状态码，进行下单return response()->json(['errorCode' => 20001, 'data' => '', 'msg' => '已经抢光了哦']);}//把当前这个秒杀的uid存储到中奖的队列里set$success = Redis::sadd($robSuccessUser, $userID);if(!$success){//已经在成功队列里了，加回库存,防止的是同个用户并发请求Redis::lpush($goods, 1);//如果抢购成功 返回状态码，进行下单return response()->json(['errorCode' => 20002, 'data' => '', 'msg' => '已经抢购过了']);}//如果抢购成功 返回状态码，进行下单return response()->json(['errorCode' => 0, 'data' => '', 'msg' => '秒杀成功']);}//创建订单public function createOrder(Request $request){//获取token$token = explode(' ',$request->header('authorization'))[1];//进行查看$userInfo = Cache::get($token);//抢购用户id$userID = $userInfo->id;//商品id$goodsID = $request->input("goods_id");//对应商品抢购成功用户集合 {1,3,4}$robSuccessUser = "success_user".$goodsID;//进行判断当前用户是否在抢成功的队列里面$result = Redis::sismember($robSuccessUser,$userID);//如果你在这里面，就抢完了if (!$result) {//如果抢购成功 返回状态码，进行下单return response()->json(['errorCode' => 20003, 'data' => '', 'msg' => '手慢了！']);}DB::beginTransaction();try{//减库存//生成订单DB::commit();//下单成功，跳转支付页面return response()->json(['errorCode' => 0, 'data' => '', 'msg' => '下单成功！']);}catch (\Exception $e){DB::rollBack();}}
}