How to create a Payment backend¶
Payment backends must be listed in settings.SHOP_PAYMENT_BACKENDS
Shop interface¶
While we could solve this by defining a superclass for all payment backends, the better approach to plugins is to implement inversion-of-control, and let the backends hold a reference to the shop instead.
The reference interface for payment backends is located at
-
class
shop.payment.api.
PaymentAPI
¶
Currently, the shop interface defines the following methods:
Common with shipping¶
-
PaymentAPI.
get_order
(request)¶ Returns the order currently being processed.
Parameters: request – a Django request object Return type: an Order
instance
-
PaymentAPI.
add_extra_info
(order, text)¶ Adds an extra info field to the order (whatever)
Parameters: - order – an
Order
instance - text – a string containing the extra order information
- order – an
-
PaymentAPI.
is_order_payed
(order)¶ Whether the passed order is fully paid or not
Parameters: order – an Order
instanceReturn type: bool
-
PaymentAPI.
is_order_complete
(order)¶ Whether the passed order is in a “finished” state
Parameters: order – an Order
instanceReturn type: bool
-
PaymentAPI.
get_order_total
(order)¶ Returns the order’s grand total.
Parameters: order – an Order
instanceReturn type: Decimal
-
PaymentAPI.
get_order_subtotal
(order)¶ Returns the order’s sum of item prices (without taxes or S&H)
Parameters: order – an Order
instanceReturn type: Decimal
-
PaymentAPI.
get_order_short_name
(order)¶ A short human-readable description of the order
Parameters: order – an Order
instanceReturn type: a string with the short name of the order
-
PaymentAPI.
get_order_unique_id
(order)¶ The order’s unique identifier for this shop system
Parameters: order – an Order
instanceReturn type: the primary key of the Order
(in the default implementation)
-
PaymentAPI.
get_order_for_id
(id)¶ Returns an
Order
object given a unique identifier (this is the reverse ofget_order_unique_id()
)Parameters: id – identifier for the order Return type: the Order
object identified byid
Specific to payment¶
-
PaymentAPI.
confirm_payment
(order, amount, transaction_id, save=True)¶ This should be called when the confirmation from the payment processor was called and that the payment was confirmed for a given amount. The processor’s transaction identifier should be passed too, along with an instruction to save the object or not. For instance, if you expect many small confirmations you might want to save all of them at the end in one go (?). Finally the payment method keeps track of what backend was used for this specific payment.
Parameters: - order – an
Order
instance - amount – the paid amount
- transaction_id – the backend-specific transaction identifier
- save – a
bool
that indicates if the changes should be committed to the database.
- order – an
Backend interface¶
The payment backend should define the following interface for the shop to be able do to anything sensible with it:
Attributes¶
-
PaymentBackend.
backend_name
¶ The name of the backend (to be displayed to users)
-
PaymentBackend.
url_namespace
¶ “slug” to prepend to this backend’s URLs (acting as a namespace)
Methods¶
-
PaymentBackend.
__init__
(shop)¶ must accept a “shop” argument (to let the shop system inject a reference to it)
Parameters: shop – an instance of the shop
-
PaymentBackend.
get_urls
()¶ should return a list of URLs (similar to urlpatterns), to be added to the URL resolver when urls are loaded. These will be namespaced with the url_namespace attribute by the shop system, so it shouldn’t be done manually.
Security¶
In order to make your payment backend compatible with the SHOP_FORCE_LOGIN
setting please make sure to add the @shop_login_required
decorator to any
views that your backend provides.