Shipping methods

To handle shipping fees in your app, there are existing shippings methods with associated calculators, but you can also create your own easily.

Existing calculators

• Colissimo

Creating your own

Create a Stall::Shipping::Calculator subclass in your app's lib/ folder, which must define two methods : #available? and #price.

In those methods, you get access to the cart with the #cart method, which will allow those methods to defined their behavior depending on the cart available data.

class MyShippingCalculator < Stall::Shipping::Calculator
  register :my_shipping_calculator

  def available?
    if cart.shipping_address
      cart.shipping_address.country.in?(['FR', 'GB'])
    end
  end

  def price
    cart.total_price > 100 ? 0 : 10
  end
end

Note : Inside the class you have access to the current cart, and the config property which is the Stall::ShippingMethod model instance.

The add it in the stall initializer :

# If the class is not in your app's autoload_paths, require it
require 'my_shipping_calculator`

Stall.configure do |config|
  config.shipping.register_calculator :my_shipping_calculator, 'MyShippingCalculator'
end

Restart your server and you should be able to access the shipping method.

Loading prices from a CSV file

Stall comes from an abstract calculator class that handles a specific CSV format to store shipping fees depending on total order weight (rows) and target country (columns).

The CSV should contain comma separated ISO-3166-1 alpha-2 country codes (as provided by the country_select gem for example) in each top-row cells and max order weight in the first column cells.

The CSV will look like the following :

	"FR,GB,DE"	"US,MX"
1	5	10
2	10	20
5	15	30
10	30	40
100	40	100

Your calculator should subclass Stall::Shipping::CountryWeightTableCaclulator and implement at least the #load_data method returning a string with a CSV contents. The calculator will parse the CSV with ruby's standard csv lib.

class MyCSVCalculator < Stall::Shipping::CountryWeightTableCaclulator
  def load_data
    File.read(Rails.root.join('vendor/shipping_prices.csv'))
  end
end

Any country that is not in the list will not be available for this shipping method.