The Clean Architecture in PHP (2015)

Introduction

Figuring out how to architect a brand new application is a big deal. Doing it the wrong way can lead to a huge headache later. Testing can become hard – or maybe even impossible – and refactoring is an absolute nightmare.

While the methods outlined in this book aren’t the only way to go about developing an application, they do provide a framework for developing applications that are:

1. Testable

2. Refactorable

3. Easy to work with

4. Easy to maintain

This book is for anyone wanting to build a medium to large sized application that must be around for a long time and/or be easily enhanced in the future. The methods outlined in this book aren’t meant for all applications, and they might be downright over kill for some.

If your application is small, or an unproven, new product, it might be best to just get it out the door as fast as possible. If it grows, or becomes successful, later applying these principles may be a good idea to create a solid, long lasting product.

The principles outlined in this book involve a learning curve. Writing code this way will slow a developer down until the methods become familiar to them.

Organization

This book begins by discussing common problems with PHP code and why having good, solid, clean code is important to the success and longevity of an application. From there, we move on to discussing some principles and design patterns that allow us to solve problems with poor code. Using these concepts, we’ll then discuss the Clean Architecture and how it further helps solve problems with bad code.

Finally, in the second half of the book, we dive into some real code and build an application following this architecture. When we’re done with our case study application, we’ll start swapping out components, libraries, and frameworks with new ones to prove out the principles of the architecture.

The Author

My name is Kristopher Wilson. I’ve been developing in PHP since around 2000. That sounds impressive on the surface, but most of those years involved writing truly terrible code. I would have benefited greatly from a book like this that outlines the principles of how to cleanly organize code.

I’ve done it all, from simple websites to e-commerce systems and bulletin boards. Mostly, I’ve concentrated on working on ERP (Enterprise Resource Planning) systems and OSS (Operational Support Systems) – software that runs the entire back office of large organizations, from manufacturing to telecommunications. I even wrote my own framework once. It was terrible, but that’s another story.

I live in Grand Rapids, Michigan with my wife and our four cats (our application to become a registered zoo is still pending). I’m one of the founders of the Grand Rapids PHP Developers (GrPhpDev) group and am highly involved with organizing, teaching, and learning from the local community.

A Word about Coding Style

I strongly prefer and suggest the use of PSR-2 coding standards. As a community, it makes it much easier to evaluate and contribute to one another’s code bases if the dialect is the same. I also strongly suggest the use of DocBlocks and helpful comments on classes and methods.

However, for brevity, the code examples in this book make a few deviations from PSR-2 standards, namely involving bracket placement, and don’t include many DocBlocks. If this is too jarring for the PSR-2 and DocBlock fan, like myself, I humbly apologize.