Chapter 1: Object-Oriented PHP

In this first part of the book, we are going to explore modern object-oriented PHP. While there isn't sufficient space in this book to do a deep dive into this topic, we hope that you will be able to use the contents of the following three chapters as a jumping point for your own further study and experimentation. To be clear, for any PHP language features you see that you don't understand, you are absolutely encouraged to put the book down and go and start reading the PHP docs so that you can gain a fuller understanding of that particular feature. To underline this, you will see frequent links to the official documentation. You are encouraged to follow these links and read into any feature that you are not intimately familiar with.

Some readers may already be very familiar with object-oriented programming (OOP) in PHP and for those, this first part might be a nice refresher. You never know, you might learn something new! If you are not familiar with modern object-oriented PHP, then there is likely to be a lot to take in. I seriously hope you don't find this overwhelming. All I can say is, it's worth persevering as OOP is fundamental to modern PHP.

This chapter is an introduction to OOP in general and includes a review of some popular object-oriented PHP projects and frameworks that you are encouraged to go and have a look at.

By the end of part 1, especially if you take the time to fill in the gaps by hitting the official docs, you should be fairly up to date with how OOP works in modern PHP.

The following topics will be covered in this chapter:

• What is OOP?
• PHP OOP basics

Before we begin this chapter in depth, you are strongly encouraged to have a thorough read through the official documentation on classes and objects:

PHP: Classes and Objects - Manual

https://www.php.net/manual/en/language.oop5.php

In this chapter, we are going to look in general at what we mean by OOP and what it means to you. We'll start by understanding what the phrase OOP actually means and compare it to some other programming styles. I will recommend some PHP projects and packages that you can look at if you want to get your hands dirty with an existing code base. After that, we are going to jump in at the deep end with a look at inheritance, and then also look at using composition instead of inheritance. After that, we'll take a quick look at the Standard PHP Library, have a look at exceptions, and understand how modern PHP projects ensure that they have robust error handling. For the big finale of this chapter, we'll dip our toes in the deep waters of metaprogramming with reflection and attributes. It's a huge amount of content to cover in a comparatively tiny amount of text.

For this chapter, and all the other chapters in the book, you can find all the code samples in the main repo for the book available on GitHub at https://github.com/PacktPublishing/The-Art-of-Modern-PHP-8