When building applications in PHP, it is often far too simple to settle for the “quick and dirty” solution – poorly written, monolithic code that will never be used again and lacks any clear intent. Since PHP is typically used in small projects that could themselves be described as “quick and dirty,” developers will excuse their poor code by stating that they will not have to work on the code again and that they have no intention of ever reusing it. The fact remains, however, that as with any job worth doing, it should be done well.

This paradigm holds true in this situation for a number of reasons. First, when you take the time to write good code, you will almost always find something reusable in any new code you write. Second, code will always require maintenance or changes. It may not be you, but it will be someone, someday – that is of course unless the code is so bad the poor fellow has to start from scratch. The intent of this article is to cover some of the most fundamental, low level rules of writing good PHP code.

The first practice we will discuss covers directory structure and security along with filesystem naming conventions for PHP applications. After that, we will cover some coding conventions such as function and variable naming, indentation, and more. Lastly we will review basic coding considerations to provide flexibility, scalability, and efficiency. Before beginning, let it be understood that some of the conventions advocated in this article could be considered a matter of preference and are by no means the single correct solution, however they are time tested and have proven effective time and again in application development.