Tuesday, 29 May 2007

Good and Bad PHP Code

Kevin Yank tries to delve about the differences between good PHP code and bad PHP code while interviewing candidates. He gives the following criteria to judge them:

Good PHP code should be structured. Long chunks of code can be broken up into functions or methods that achieve sub-tasks with simple code, while non-obvious snippets should be commented to make their meaning plain. As much as possible, you should separate frontend HTML/CSS/JavaScript code from the server-side logic of your applications. PHP’s object oriented programming features give you some tools to break up your applications into sensible units.

Good PHP code should be consistent. Whether that means setting rules for the names of variables and functions, adopting standard approaches to recurring tasks like database access and error handling, or simply making sure all of your code is indented the same way, consistency makes your code easier for others to read.

Good PHP code should be portable. PHP has a number of features, such as magic quotes and short tags that can break fragile code when they are switched on or off. If you know what you’re doing, however, you can write code that works by adapting to its environment.

Good PHP code should be secure. While PHP offers performance and flexibility out of the box, it leaves important issues like security entirely in the hands of the developer. A deep understanding of potential security holes like Cross-Site Scripting (XSS), Cross-Site Request Forgeries (CSRF), code injection vulnerabilities, and character-encoding loopholes is essential for a professional PHP developer these days.

He also gives some examples of good and bad code and also some tips to make it look good.