本文共 3003 字，大约阅读时间需要 10 分钟。
1. models.py的修改
class ShoppingCart(models.Model): """ 购物车 """ user = models.ForeignKey(User, verbose_name=u'用户', on_delete=models.CASCADE) goods = models.ForeignKey(Goods, verbose_name=u'商品', on_delete=models.CASCADE) nums = models.IntegerField(default=0, verbose_name=u'购买数量') add_time = models.DateTimeField(default=datetime.now, verbose_name=u'添加时间') class Meta: verbose_name = u'购物车' verbose_name_plural = verbose_name# 建立联合唯一 unique_together = ('user', 'goods') def __str__(self): return "%s(%d)".format(self.goods.name, self.nums) serializers.py
from rest_framework import serializersfrom goods.models import Goodsfrom .models import ShoppingCart# 用Serializer而不是ModelSerializer的原因;# 1.更灵活2.因为我们建立了联合唯一。所以如果使用ModelSerializer的话会去校验是否唯一# 但是购物车有这么一个情况，就是在点击添加购物车的按钮时，会判断购物车是否有# ，如果有。不是抛异常，而是nums字段加1 所以如果用ModelSerializer的话会# 抛异常，所以这里需要自定义。class ShopCartSerializer(serializers.Serializer): user = serializers.HiddenField( default=serializers.CurrentUserDefault() ) nums = serializers.IntegerField(required=True, min_value=1,label="数量", error_messages={ "min_value":"商品数量不能小于1", "required": '请选择购买数量' })# goods是外键 所以需要用到PrimaryKeyRelatedField。并且指定外键的model类 goods = serializers.PrimaryKeyRelatedField(required=True, queryset=Goods.objects.all())# 重写create函数，已满足我们的功能需求 def create(self, validated_data):# user对象是保存在self.context["中"]# validated_data中的数据类型已经做好转换了 user = self.context["request"].user nums = validated_data['nums'] goods = validated_data['goods']# 是否存在，是就nums加数量 否就创建记录 existed = ShoppingCart.objects.filter(user = user, goods = goods) if existed: existed = existed[0] existed.nums += nums existed.save() else: existed = ShoppingCart.objects.create(**validated_data) return existed views.py
from rest_framework import viewsetsfrom rest_framework.permissions import IsAuthenticatedfrom utils.permissions import IsOwnerOrReadOnlyfrom rest_framework_jwt.authentication import JSONWebTokenAuthenticationfrom rest_framework.authentication import SessionAuthenticationfrom .serializers import ShopCartSerializerfrom .models import ShoppingCart# Create your views here.class ShoppingCartViewset(viewsets.ModelViewSet): """ 购物车功能 list: 获取购物车详情 create: 加入购物车 delete: 删除购物车记录 """ permission_classes = (IsAuthenticated, IsOwnerOrReadOnly) authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication) serializer_class = ShopCartSerializer def get_queryset(self): return ShoppingCart.objects.filter(user=self.request.user)
urls.py
from trade.views import ShoppingCartViewset#购物车router.register('shopcarts', ShoppingCartViewset, base_name='shopcarts') 关于PrimaryKeyRelatedField的官方文档
s
完结
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