Websydian Express Background
Overview
Websydian Express provides a web-infrastructure for developing and deploying web-based business applications. This document gives a background overview of the Websydian Express architecture and how it is used.
When developing web applications the developer must focus on a lot of technologies related to web development in addition to the flow and logic of the application. These technologies relates to session handling, user management, input validation, security, etc.
While these things are important aspects of a web application it is not something that brings value to the application (though if not present it will certainly have a negative impact on the application).
As Websydian Express has built-in support for these web technologies the web developer can focus on the business logic of the application.
Business Process
The business process is the basic element used in Websydian Express.
A business process is a self-contained modular component that performs a specific task.
Some examples could be:
- A process that lists a product catalog
- A shopping basket process that list the products selected for an order with the possibility of updating or removing entries in the shopping basket.
A business process can consist of a single page or it can span multiple pages.
A web application is then designed as the combination of multiple business process that each solve a specific task within the application.
This modular design makes the web application more flexible and robust to design changes as it is possible to update the business processes that are subject to change without affecting the other business processes that are part of the web application.
Websydian Express
Websydian Express is a platform for deploying business processes developed with Websydian.
Websydian Express also includes a web administration tool that is used to deploy and manage business processes as well as configuring users and their access to the business processes.
Furthermore the administration tool is used to configure the layout and structure of the web application. That is how the web application is divided into frames (sub-pages) and the layout of the menu.
Examples of the tasks an administrator is capable of doing using the interface:
- Create and maintain users.
- Decide who is authorized for a specific business process.
- Attach the business process to a menu item in a menu bar.
- Define menus, sub-menus, and menu items.
- Specify different templates for one process, thus customizing the behavior for a specific purpose.
- ...and many other things
Websydian Express Developer
Websydian Express Developer is a framework for developing business processes for Websydian Express. This is done in almost the same way as when developing a standard web application with Websydian. However, there are some differences because with Websydian Express the web application is divided into self-contained independent business processes, whereas the standard way of developing a Websydian application can be seen as developing one big business process.
The figure below shows the Websydian Circle in a Websydian Express environment.
The Websydian Circle for a Websydian Express business process
The differences between standard Websydian development and Websydian Express development are summarized below.
- EventHandler/PageGenerator
- EventHandler and PageGenerator functions have the same role as in a standard Websydian application. Within Websydian Express they are used to design the events (buttons) and pages of a business process.
- The EventHandler and PageGenerator functions must be self-contained, meaning that they must only call other EventHandler/PageGenerator functions within the business process.
- ProcessEntryPoint
- This is the entry point into a business process. This function will be called by the Websydian Express runtime. In most cases the ProcessEntryPoint function will only contain a call to the first page (PageGenerator function) within the business process. In this way the ProcessEntryPoint function can be seen as the "CallFirstPageGenerator" function for business processes.
- EventDispatcher
- As opposed to a standard Websydian application it is not necessary to develop an EventDispatcher function when using Websydian Express. The EventDispatcher is shipped as a binary object with Websydian Express Runtime and the tasks handled by the EventDispatcher (session creation, security, call first page, call EventHandler) is now built-in the Websydian Express and configured with the web administration tool.
- ProcessEntryEventHandler
- This function finds the appropriate ProcessEntryPoint function based on the input in the web event. Instances of this function are distributed with the Websydian Express runtime and in most cases a developer does not need to create new versions of this function.