As anyone who's been developing applications (web or otherwise) knows, there are certain things that you just don't do when you're doing things like adding features or changing the code of a production application. There are some general rules to follow and this new article on the PHPClasses.org website reminds us of just a few.

This article describes software development practices that have been used to prevent problems that can break Web sites.

Included in his list are things like:

• Handle unexpected conditions Test your code
• Monitor your site errors and act upon them
• Do not disclose errors to the users
• Do what you can as you can never get defensive enough

He also recommends two resources for some additional reading - the Wikipedia entry for "defensive programming" and a chapter from Getting Real (from 37 Signals) about how to "Get Defensive".