Python Web框架 Django - 项目-购物车数据同步

购物车数据同步(中间件）：

class SessionSyncMiddleware(MiddlewareMixin):

    def process_response(self, request, response):
        # 没有登录就不管数据同步
        # 登录情况才做数据从session同步到数据库，且重新更新session数据
        user_id = request.session.get('user_id')
        if user_id:
            # 登录情况
            session_goods = request.session.get('goods')
            if session_goods:
                # 1.判断session中商品是否存在于数据库中，如果存在，则更新
                # 2.如果不存在则创建
                shop_carts = ShoppingCart.objects.filter(user_id=user_id)

                # 更新购物车中的商品数量
                data = []
                for goods in shop_carts:
                    for se_goods in session_goods:
                        if se_goods[0] == goods.goods_id:
                            goods.nums = se_goods[1]
                            goods.save()
                            # 向data中添加编辑了的商品的id值
                            data.append(se_goods[0])
                # 添加
                session_goods_ids = [i[0] for i in session_goods]
                add_goods_ids = list(set(session_goods_ids) - set(data))

                for add_goods_id in add_goods_ids:
                    for session_good in session_goods:
                        if add_goods_id == session_good[0]:
                            ShoppingCart.objects.create(user_id=user_id, goods_id=add_goods_id, nums=session_good[1])

            # 将数据库中数据同步到session中
            new_shop_carts = ShoppingCart.objects.filter(user_id=user_id)
            session_new_goods = [[i.goods_id, i.nums, i.is_select] for i in new_shop_carts]
            request.session['goods'] = session_new_goods

        return response

购物车数据删除：

def del_cart(request, id):
    if request.method == 'GET':
        user_id = request.session.get('user_id')
        if user_id:
            # 登录情况，删除数据库中的数据
            ShoppingCart.objects.filter(user_id=user_id, goods_id=id).delete()
        # 没有登录情况,删除session中的数据
        session_goods = request.session.get('goods')
        for goods in session_goods:
            if goods[0] == int(id):
                session_goods.remove(goods)
        request.session['goods'] = session_goods
        return HttpResponseRedirect(reverse('carts:cart'))

同步数据库商品数目：

def change_cart(request):
    if request.method == 'POST':
        # 获取前端ajax传递的goods_id，is_select,nums
        goods_id = int(request.POST.get('goods_id'))
        is_select = request.POST.get('is_select')
        nums = request.POST.get('nums')
        # 获取session中商品的信息
        session_goods = request.session.get('goods')
        for goods in session_goods:
            # goods:[goods_id, nums, is_select]
            if goods_id == goods[0]:
                # 修改session中的商品的数量和选择状态
                goods[1] = int(nums) if nums else goods[1]
                goods[2] = is_select if nums else goods[2]
        request.session['goods'] = session_goods
        return JsonResponse({'code': 200, 'msg': '请求成功'})