将值附加到序列化程序数据

Question

I am fetching some customer credit cards from an API. The data does not indicate the customers 'default' card, although another API can do this. I would like to filter over the first data set and add a value indicating if the card matches the default card.

    customer = Customer.objects.get(subscriber=request.user.organization_id)
    default_payment_method = customer.default_payment_method.organization_id
    cards = PaymentMethod.objects.filter(customer=customer.djstripe_id)
    serializer = PaymentMethodSerializer(cards, many=True)

    # something like this, although I know this is not right
    for card in cards:
        if card.id == default_payment_method:
             set card.default=True

    return Response(cards)

Right now the data looks like

cards = [
         {"id":"pm_1G6u80AFXbZqlwaURe8swF23","billing_details":{"address":{"city":...}}},
         {"id":"pm_1G6u80AFXbZqlwaURe8swF23","billing_details":{"address":{"city":...}}}
         ...
        ]

But I would like it to look like:

 cards = [
         {"id":"pm_1G6u80AFXbZqlwaURe8swF23","default": "True", "billing_details":{"address":{"city":...}}},
         {"id":"pm_1G6u80AFXbZqlwaURe8swF23","default": "False", "billing_details":{"address":{"city":...}}}
         ...
        ]

Answer 1

You can do it or serializer level. Use SerializerMethodField :

class PaymentMethodSerializer(serializers.ModelSerializer):
    default = SerializerMethodField()

    class Meta:
        model = PaymentMethod

    def get_default(self, obj):
        return obj.id == self.context["default_payment_method"]

Note than to make this self.context["default_payment_method"] work you should add default_payment_method to serializer context in your view:

customer = Customer.objects.get(subscriber=request.user.organization_id)
default_payment_method = customer.default_payment_method.organization_id
cards = PaymentMethod.objects.filter(customer=customer.djstripe_id)
serializer = PaymentMethodSerializer(cards, many=True, context={'default_payment_method': default_payment_method})

return Response(serializer.data)