1060 Forum Guide

The 1060 Forum is a multi-user bulletin board application that is pre-installed with the NetKernel distribution. This guide provides a deconstruction of the Forum to show techniques used in a production web-application on NetKernel.

It is important to emphasize that web-applications are only one of many types of solution on NetKernel. As such, this guide describes many general-purpose design-patterns and development techniques which can be applied to any solution.

Service-Composition

The conventional approach for developing web-applications is to treat each page of the application as a self contained unit of the application. PHP, JSP, ASP mix dynamic content with a static HTML template - when a page is accessed, the active procedural code is executed and the static template is populated.

Generally for large-scale Web-applications the content is a representation of a query made on a back-end database. Some simple applications might make the database call directly in the page. More sophisticated applications use a so-called '3-tier architecture' where the front-end active page invokes a middleware layer which may or may not offer transactions, data persistence and other bells and whistles. The middleware layer interacts with the back-end database.

The page-based approach has, with varying degrees of sophistication, characterized the general design-pattern of most web-applications to date.

Numerous frameworks have been created that provide utility services to a page - for example access control, application flow, session management etc. Whilst these are helpful the fundamental property of a page-based approach to web-applications remains - this approach creates a tight binding between the presentational content of a page and the logic which generates the data.

As we proceed we will demonstrate that Web-applications on NetKernel offer a new and flexible decoupling between presentation and logic - we characterize this as Service-based Composition.