Example cart modifier for django-shop

modifiers.py

# -*- coding: utf-8 -*-
import decimal
from django.conf import settings
from shop.cart.cart_modifiers_base import BaseCartModifier


class FixedShippingCosts(BaseCartModifier):
#	"""
#	This will add a fixed amount of money for shipping costs.
#	"""
	def process_cart(self, cart, state):
		shipping_cost = decimal.Decimal(settings.SHOP_SHIPPING_FLAT_RATE)
		cart.current_total = cart.current_total + shipping_cost
		cart.extra_price_fields.append(
			('Shipping costs', shipping_cost))
		return cart


class FixedTaxRate(BaseCartModifier):
	def process_cart(self, cart, state):
		"""
		This will be called once per Cart, after every line item was treated
		The subtotal for the cart is already known, but the Total is 0.
		Like for the line items, total is expected to be calculated in the cart's
		update() method.
		
		Line items should be complete by now, so all of their fields are accessible
		
		Subtotal is accessible, but total is still 0.0. Overrides are expected to
		update cart.current_total.
		
		The state parameter is only used to let implementations store temporary
		information to pass between cart_item_modifers and cart_modifiers
		"""
		field = self.get_extra_cart_price_field(cart)
		if field != None:
			price = field[1]
			cart.current_total = cart.current_total + price
			cart.extra_price_fields.append(field)
		taxes = cart.current_total * decimal.Decimal('0.19')
		to_append = ('Taxes total', taxes)
		cart.extra_price_fields.append(to_append)
		cart.current_total = cart.current_total + taxes
		return cart