How to add an own shipping price calculator

In this how to you will learn how to add your own shipping price calculator.

Create an application

First you need to create a default Django application (or use an existing one), where you can put in your plugin. If you do not know how to do this, please refer to the excellent Django tutorial.

Implement the ShippingMethodPriceCalculator class

The main part of the plugin consists of a class which must provide a certain API.

Create the class

Create a class which inherits from lfs.plugins.ShippingMethodPriceCalculator:

from lfs.plugins import ShippingMethodPriceCalculator

class MyShippingMethodPriceCalculator(ShippingMethodPriceCalculator):
    pass

Add the get_price_net and get_price_gross methods

This methods are called from LFS to display the shipping price or to calculate the total price of the cart or order.

def get_price_net(self):
    # This doesn't make much sense, but the net price is always 11.0
    return 11.0

def get_price_gross(self):
    return 11.0 * ((100 + self.shipping_method.tax.rate) / 100)

The complete plugin

Following all pieces are sticked together to the complete plugin:

from lfs.plugins import ShippingMethodPriceCalculator

class MyShippingMethodPriceCalculator(ShippingMethodPriceCalculator):
    def get_price_net(self):
        # This doesn't make much sense, but the net price is always 11.0
        return 11.0

    def get_price_gross(self):
        return 11.0 * ((100 + self.shipping_method.tax.rate) / 100)

Plug in your payment method

Now as the code is ready, you can easily plugin your shipping method price calculator:

1. Add your application to the PYTHONPATH.
2. Add the class to the LFS_SHIPPING_METHOD_PRICE_CALCULATORS setting.
3. If your are using models (which is completely up to you), add the application to settings.INSTALLED_APPS and sync your database.
4. Add a new shipping method and select your price calculator within the price_calculator field.
5. Save the shipping method.

Further hints

• Within the ShippingMethodPriceCalculator the current request and the shipping method are available as instance variables:

  self.request
  self.shipping_method
  

• With the request you have access to the current cart (in case you need it):

  from lfs.cart.utils import get_cart
  cart = get_cart(self.request)
  

• With the request you have access to the current customer (in case you need it):

  from lfs.customer.utils import get_customer
  customer = get_customer(self.request)