class ShopCartViewset(viewsets.ModelViewSet):
serializer_class = ShopCartSerializer
permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
# 我们希望让前端通过goods_id来查询数据,实际上在Serializer中我们也会将goods_id返回给前端
lookup_field = "goods_id"
def get_serializer_class(self):
if self.action == 'list':
return ShopCartDetailSerializer
else:
return ShopCartSerializer
# return ShopCartDetailSerializer
def get_queryset(self):
return ShoppingCart.objects.filter(user=self.request.user)
def perform_create(self, serializer):
shop_cart = serializer.save()
goods = shop_cart.goods
nums = serializer.validated_data['nums']
goods.goods_num -= nums
# goods.goods_num -= shop_cart.nums 错了
goods.save()
def perform_destroy(self, instance):
goods = instance.goods
goods.goods_num += instance.nums
goods.save()
instance.delete()
def perform_update(self, serializer):
# 修改商品的库存,通过比对购物车更新前后该商品的数量
# newstorage = oldstorage + (after-before)
existed_record = ShoppingCart.objects.get(id=serializer.instance.id)
existed_nums = existed_record.nums
saved_record = serializer.save()
nums = saved_record.nums-existed_nums
goods = saved_record.goods
goods.goods_num -= nums
goods.save()
class ShopCartSerializer(serializers.Serializer):
# 这里不用ModelSerializer的原因是, 这里需要使用user, goods联合索引
#
# 我们当然可以使用联合索引来控制唯一性,但问题是,当我们重复添加商品时(只是希望他更新nums字段时(但是实际上是用update方法更新的)),
# 第二条就会报错,因为会验证失败,所以我们不能再此使用联合索引,而需要使用更加灵活的Serializer并重写create方法
#
# 如果是ModelSerializer, 那么重复添加同一个商品时View中继承的CreateMinx中create方法中的验证就会报错 == serializer.is_valid(
# raise_exception=True) == 报错(因为是联合索引)
#
# 这样就不会再执行serializer.save()
# 方法保存了,所有这里必须使用Serializer,重写create方法,而不使用联合索引
#
# 总结,使用联合索引时,如果需要重复创建商品,但实际上只更新某个字段,CreateMinx中的create方法验证不通过,必须使用Serializer,重写create方法
user = serializers.HiddenField(
default=serializers.CurrentUserDefault()
)
nums = serializers.IntegerField(required=True,label="数量",min_value=1,
error_messages={
"min_value": "商品数量不能小于一",
"required": "请选择购买数量"
})
goods = serializers.PrimaryKeyRelatedField(queryset=Goods.objects.all(),required=True)
# 重写create方法,判断是否存在,存在加1,不存在添加数据
def create(self, validated_data):
# 拿到user,nums,good
user = self.context['request'].user
nums = validated_data['nums']
goods = validated_data['goods']
existed = ShoppingCart.objects.filter(user=user,goods=goods)
if existed:
existed = existed[0]
# existed.objects.update(nums=(nums+1))
existed.nums += nums
existed.save()
else:
existed = ShoppingCart.objects.create(**validated_data)
return existed
def update(self, instance, validated_data):
# 修改商品数量
instance.nums = validated_data['nums']
instance.save()
return instance
注意点一
这里不用ModelSerializer的原因是, 这里需要使用user, goods联合索引
我们当然可以使用联合索引来控制唯一性,但问题是,当我们重复添加商品时(只是希望他更新nums字段时(但是实际上是用update方法更新的)),
第二条就会报错,因为会验证失败,所以我们不能再此使用联合索引,而需要使用更加灵活的Serializer并重写create方法
如果是ModelSerializer, 那么重复添加同一个商品时View中继承的CreateMinx中create方法中的验证就会报错 serializer.is_valid(
raise_exception=True) 报错(因为是联合索引)
这样就不会再执行serializer.save()
方法保存了,所有这里必须使用Serializer,重写create方法,而不使用联合索引
总结,使用联合索引时,如果需要重复创建商品,但实际上只更新某个字段,CreateMinx中的create方法验证不通过,必须使用Serializer,重写create方法
注意点二
serializer中使用外键字段,参考官方文档可知
goods = serializers.PrimaryKeyRelatedField(queryset=Goods.objects.all(),required=True)
这里的外键与直接写一个类不同的是,只会将主键(goods_id)返回给前端,而不是返回goods中的所有字段。
注意点三
init_data 指的是最原始的没有经过验证的数据
validated_data 指定是已经验证转换过的数据,比如nums已经验证无误并转换成了int类型
注意点四
这里取出user,是从self.context[‘request’].user中取出来的
注意点五
goods = validated_data['goods']
这里取出的goods是Good对象
注意点六
创建的时候使用的是**validated_data,并将创建的实例返回
existed =ShoppingCart.objects.create(**validated_data)
return existed
注意点七
如果要更新数据,serializer中必须重新update方法,该方法在BaseSerializer中,Serializer继承时并没有重写,所以需要我们手动重写
class ShopCartDetailSerializer(serializers.ModelSerializer):
# 每个用户下的相同商品只会存在一条纪录
goods = GoodsSerializer(many=False, read_only=True)
class Meta:
model = ShoppingCart
fields = ("goods", "nums")
注意:每个用户下的相同商品只会存在一条纪录,所以many=False
重写get_serializer_class 动态获取类
def get_serializer_class(self):
if self.action == 'list':
return ShopCartDetailSerializer
else:
return ShopCartSerializer
# return ShopCartDetailSerializer
class OrderViewset(mixins.ListModelMixin, mixins.RetrieveModelMixin, mixins.CreateModelMixin, mixins.DestroyModelMixin,
viewsets.GenericViewSet):
"""
订单管理
list:
获取个人订单
delete:
删除订单
create:
新增订单
"""
permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
serializer_class = OrderSerializer
def get_queryset(self):
return OrderInfo.objects.filter(user=self.request.user)
def get_serializer_class(self):
# delete不会调用这个方法
print('......',self.action)
if self.action == "retrieve":
return OrderDetailSerializer
return OrderSerializer
def perform_create(self, serializer):
order = serializer.save()
shop_carts = ShoppingCart.objects.filter(user=self.request.user)
for shop_cart in shop_carts:
order_goods = OrderGoods()
order_goods.goods = shop_cart.goods
order_goods.goods_num = shop_cart.nums
order_goods.order = order
order_goods.save()
shop_cart.delete()
return order
class OrderSerializer(serializers.ModelSerializer):
user = serializers.HiddenField(
default=serializers.CurrentUserDefault()
)
# 不允許前端提交
pay_status = serializers.CharField(read_only=True)
trade_no = serializers.CharField(read_only=True)
order_sn = serializers.CharField(read_only=True)
pay_time = serializers.DateTimeField(read_only=True)
# alipay_url = serializers.SerializerMethodField(read_only=True)
# def get_alipay_url(self, obj):
# alipay = AliPay(
# appid="",
# app_notify_url="http://127.0.0.1:8000/alipay/return/",
# app_private_key_path=private_key_path,
# alipay_public_key_path=ali_pub_key_path, # 支付宝的公钥,验证支付宝回传消息使用,不是你自己的公钥,
# debug=True, # 默认False,
# return_url="http://127.0.0.1:8000/alipay/return/"
# )
#
# url = alipay.direct_pay(
# subject=obj.order_sn,
# out_trade_no=obj.order_sn,
# total_amount=obj.order_mount,
# )
# re_url = "https://openapi.alipaydev.com/gateway.do?{data}".format(data=url)
#
# return re_url
def generate_order_sn(self):
# 当前时间+userid+随机数
from random import Random
random_ins = Random()
order_sn = "{time_str}{userid}{ranstr}".format(time_str=time.strftime("%Y%m%d%H%M%S"),
userid=self.context["request"].user.id, ranstr=random_ins.randint(10, 99))
return order_sn
def validate(self, attrs):
attrs["order_sn"] = self.generate_order_sn()
return attrs
class Meta:
model = OrderInfo
fields = "__all__"
class OrderDetailSerializer(serializers.ModelSerializer):
# 注意,这个goods其实是ordergoods,是与OrderInfo表关联的
goods = OrderGoodsSerialzier(many=True)
# alipay_url = serializers.SerializerMethodField(read_only=True)
# def get_alipay_url(self, obj):
# alipay = AliPay(
# appid="",
# app_notify_url="http://127.0.0.1:8000/alipay/return/",
# app_private_key_path=private_key_path,
# alipay_public_key_path=ali_pub_key_path, # 支付宝的公钥,验证支付宝回传消息使用,不是你自己的公钥,
# debug=True, # 默认False,
# return_url="http://127.0.0.1:8000/alipay/return/"
# )
#
# url = alipay.direct_pay(
# subject=obj.order_sn,
# out_trade_no=obj.order_sn,
# total_amount=obj.order_mount,
# )
# re_url = "https://openapi.alipaydev.com/gateway.do?{data}".format(data=url)
#
# return re_url
class Meta:
model = OrderInfo
fields = "__all__"
class OrderGoodsSerialzier(serializers.ModelSerializer):
# 每个订单下的相同商品只会存在一条纪录
goods = GoodsSerializer(many=False)
class Meta:
model = OrderGoods
fields = "__all__"