Retrieve a Card with Customer is throwing an error

Question

I'm attempting to create a way in Django for a subscriber to change their default payment method to an existing card on file with them. When I attempt to access the Stripe card I receive an error "Can't retrieve a card without a customer, recipient or account ID. Use customer.sources.retrieve('card_id'), recipient.cards.retrieve('card_id'), or account.external_accounts.retrieve('card_id') instead." despite providing the customer.

I've attempted to remove other logic from the view. I have no idea where to go from here.

@login_required
# @is_subscriber
def update_payment(request):
    title = 'Update Payment Methods'
    description = title
    key = settings.STRIPE_PUBLISHABLE_KEY
    user_membership = UserMembership.objects.get(user=request.user)
    current_payment_methods = stripe.PaymentMethod.list(customer=user_membership.stripe_customer_id,
                                                        type='card')
    customer = stripe.Customer.retrieve(user_membership.stripe_customer_id)
    if request.method == 'POST':
        if request.POST.get('source_obj'):
            logger.info('User is attempting to delete a paid payment method')
            card_id = request.POST.get('source_obj')
            if len(current_payment_methods) > 1:
                stripe.Customer.delete_source(
                    user_membership.stripe_customer_id, card_id
                )
                message = 'This payment method has been removed from your account.'
                messages.info(request, message=message)
                logger.info('User has deleted a payment method')
            elif len(current_payment_methods) <= 1:
                message = 'You must have at least one payment method associated with your account.'
                messages.error(request, message=message)
                logger.info('User failed to delete only payment method.')
            return HttpResponseRedirect(request.META.get('HTTP_REFERER'))
        if request.POST.get('new_prim'):
            logger.info('User is changing their default payment method.')

            card_id = request.POST.get('new_prim')
            print(card_id)
            card = stripe.Card.retrieve(id=card_id, customer=user_membership.stripe_customer_id)
            stripe.Customer.modify(user_membership.stripe_customer_id,
                                   default_source=card)

            message = 'You have changed your primary payment method.'
            messages.success(request, message=message)
        else:
            logger.info('Customer is adding a payment method.')
            stripe.Customer.create_source(
                user_membership.stripe_customer_id,
                source=request.POST.get('stripeToken')
            )
            message = 'You have added this payment method to your account.'
            messages.success(request, message=message)
        return HttpResponseRedirect(request.META.get('HTTP_REFERER'))
    return render(request, 'memberships/update_payment.html',
                  {'title': title, 'description': description, 'key': key,
                   'current_payment_methods': current_payment_methods,
                   'customer': customer})

Return this error instead of a successful response.

"Can't retrieve a card without a customer, recipient or account ID. Use customer.sources.retrieve('card_id'), recipient.cards.retrieve('card_id'), or account.external_accounts.retrieve('card_id') instead."

Answer 1

Solution is to retrieve the card THROUGH the customer object.

            customer = stripe.Customer.retrieve(user_membership.stripe_customer_id)
            card = customer.sources.retrieve(card_id)
            stripe.Customer.modify(user_membership.stripe_customer_id,
                                   default_source=card)

Answer 2

If the card is already associated with the Customer, you can do this with just one API request:

customer = stripe.Customer.modify('cus_123',default_source='card_123')

When retrieve a Card, you can also do that into one API request without having to retrieve the Customer first:

card = stripe.Customer.retrieve_source('cus_123', 'card_123')