对订单结算理解

class CartSKUSerializer(serializers.ModelSerializer):
    """
    购物车商品数据序列化器
    """
    count = serializers.IntegerField(label=‘数量‘)

    class Meta:
        model = SKU
        fields = (‘id‘, ‘name‘, ‘default_image_url‘, ‘price‘, ‘count‘)


class OrderSettlementSerializer(serializers.Serializer):
    """
    订单结算数据序列化器
    """
    freight = serializers.DecimalField(label=‘运费‘, max_digits=10, decimal_places=2)
    skus = CartSKUSerializer(many=True)

class OrderSettlementView(APIView):
    """
    订单结算
    """
    permission_classes = [IsAuthenticated]

    def get(self, request):
        """
        获取
        """
        user = request.user

        # 从购物车中获取用户勾选要结算的商品信息
        redis_conn = get_redis_connection(‘cart‘)
        redis_cart = redis_conn.hgetall(‘cart_%s‘ % user.id)
        cart_selected = redis_conn.smembers(‘cart_selected_%s‘ % user.id)

        cart = {}
        for sku_id in cart_selected:
            cart[int(sku_id)] = int(redis_cart[sku_id])

        # 查询商品信息
        skus = SKU.objects.filter(id__in=cart.keys())
        for sku in skus:
            sku.count = cart[sku.id]

        # 运费
        freight = Decimal(‘10.00‘)

        serializer = OrderSettlementSerializer({‘freight‘: freight, ‘skus‘: skus})
        return Response(serializer.data)