PaymentWebShop Parts

Introduction   Implementing    Other Uses    Parts    

• Abstract Entities

• Extension of Shop Entity

• Payment Gateway Functions

• Payment Workflow Diagram
   

This document describes the objects of the Websydian PaymentWebShop pattern. PaymentWebShop inherits from WebShop and extends WebShop with entity attributes, functions and changes to functions concerning online payment. Refer to the WebShop Parts section for a description of the objects inherited from WebShop.

Abstract Entities

The following abstract entities are defined:

• The CreditCardTemplate abstract entity is a template for a collection of common credit card data fields. If the fields of the template matches the credit card fields of the payment gateway protocol, it is convenient to use the Fetch-view of CreditCardTemplate to populate the webinput variable of SendToExternalServer Event handler functions.
• The PaymentGateway abstract entity is an inheritance placeholder for the ExternalServerControl pattern. PaymentGateway.Data.Application is ancestor of the Shop entity.

Extension of Shop Entity

Furthermore, the Shop entity inherits from PaymentWebShop.Abstract.PaymentGateway and through this inheritance it is ensured that the correct Shop instance is loaded when pages with external events is generated.

Payment Gateway Functions

The following page generators and event handlers are defined in order to support online payments verified by a payment gateway:

• The Web.Ordering.Submit Payment function is a PageGeneratorWithExternalEvent function. The OK event handler models the external event that is sent to a payment gateway when the web user accepts to pay for the purchase.
• The Web.PaymentGateway.LoadOkPage function is a ReceiveFromExternalServer event handler. When activated, it calls the Order Confirmation for User or Order Confirmation for Visitor page generator, depending on whether a registered user has logged in or not.
• The Web.PaymentGateawy.LoadErrorPage function is a ReceiveFromExternalServer event handler. When activated, it calls the Web.Ordering.Payment Error page generator.

Payment Workflow Diagram

The workflow diagram of the payment process is illustrated below:

Payment Workflow Diagram

The call from Submit Payment.Ok to PaymentGateway is not strictly within the model, as the Ok event is invoked as an external server event rather than as a normal, application-internal event.