（生鲜项目）13. 商品类别的数据接口

from .models import GoodsCategory

# 商品类别接口的序列化
# 让goods的category字段全量显示
class CategorySerializer3(serializers.ModelSerializer):
    class Meta:
        model = GoodsCategory
        fields = "__all__"  # 取所有字段


class CategorySerializer2(serializers.ModelSerializer):
    sub_cat = CategorySerializer3(many=True) # many=True, 即声明该字段有多个值

    class Meta:
        model = GoodsCategory
        fields = "__all__"  # 取所有字段


class CategorySerializer(serializers.ModelSerializer):
    sub_cat = CategorySerializer2(many=True)  # many=True, 即声明该字段有多个值

    class Meta:
        model = GoodsCategory
        fields = "__all__"  # 取所有字段

from .serializers import CategorySerializer

# 商品分类接口
# 需求: 一类里面嵌套二类, 二类里面嵌套三类
# RetrieveModelMixin的功能是帮我们完成url的配置, /categorys/id, 通过输入id就可以拿到指定的某个元素
class CategoryViewSet(mixins.ListModelMixin, mixins.RetrieveModelMixin,viewsets.GenericViewSet):
    """
    list:
        商品分类列表数据
    """
    queryset = GoodsCategory.objects.filter(category_type=1)
    serializer_class = CategorySerializer

from goods.views import CategoryViewSet


# 配置category的url, 无需单独配置category/id的url
router.register(r‘categorys‘, CategoryViewSet, basename="categorys")  # router会自动把get转到list上,把post转到create上