Is it possible to configure payment methods on category-specific or product-specific basis in Satchmo?

Question

I have a Satchmo-powered shop that needs to have a special item category available only for users that pay by cash-on-delivery method.

Short of hard-coding the checkout process, is there any easy way I can use to restrict payment options for particular product category to cash-on-delivery only?

Answer 1

Solution is that Satchmo emits signals almost for every action, so on construction of payment methods form you have to listen to a specific signal and then redefine methods kwarg variable which gets passed to listener:

from payment.signals import payment_methods_query

def on_payment_methods_query(sender, methods=None, cart=None, order=None, contact=None, **kwargs):
    if not cart.is_empty:
        for item in cart.cartitem_set.all():
            special_products = settings.SPECIAL_PRODUCTS #(1, 15, 25, 75)
            if item.product_id in special_products:
                # methods is a list of (option_value, option_label) tuples
                methods = [m for m in methods if m[0] in ('COD',)]
                return
payment_methods_query.connect(on_payment_methods_query)