David Chandler

One of the persistent headaches of Web application development is the developer's inability to control the sequence in which application "pages" are executed. The back button, refresh, bookmarks, double-clicks, and browsers' inconsistent page-caching behavior all create special problems that result in everything from "variable undefined" errors to duplicate data records. To prevent these errors, developers have often resorted to passing around flag variables and status variables that make code hard to maintain over time. In this article, I explore a way to gain positive control of application page flow in server-side code, resulting in code that is more robust, more secure, and more reusable. Controlling Page Sequencing with an Event-Driven State Machine It has been said that the difference between an in-house application and commercial software is that for an in-ho... (more)