Book Image

PHP 8 Programming Tips, Tricks and Best Practices

By : Doug Bierer
Book Image

PHP 8 Programming Tips, Tricks and Best Practices

By: Doug Bierer

Overview of this book

Thanks to its ease of use, PHP is a highly popular programming language used on over 78% of all web servers connected to the Internet. PHP 8 Programming Tips, Tricks, and Best Practices will help you to get up-to-speed with PHP 8 quickly. The book is intended for any PHP developer who wants to become familiar with the cool new features available in PHP 8, and covers areas where developers might experience backward compatibility issues with their existing code after a PHP 8 update. The book thoroughly explores best practices, and highlights ways in which PHP 8 enforces these practices in a much more rigorous fashion than its earlier versions. You'll start by exploring new PHP 8 features in the area of object-oriented programming (OOP), followed by enhancements at the procedural level. You'll then learn about potential backward compatible breaks and discover best practices for improving performance. The last chapter of the book gives you insights into PHP async, a revolutionary new way of programming, by providing detailed coverage and examples of asynchronous programming using the Swoole extension and Fibers. By the end of this PHP book, you'll not only have mastered the new features, but you'll also know exactly what to watch out for when migrating older PHP applications to PHP 8.
Table of Contents (17 chapters)
Section 1: PHP 8 Tips
Section 2: PHP 8 Tricks
Section 3: PHP 8 Best Practices

Using constructor property promotion

Aside from the Just-In-Time (JIT) compiler, one of the greatest new features introduced in PHP 8 is constructor property promotion. This new feature combines property declarations and argument lists in the __construct() method signature, as well as assigning defaults. In this section, you will learn how to substantially reduce the amount of coding required in property declarations as well as in the __construct() method signature and body.

Property promotion syntax

The syntax needed to invoke constructor property promotion is identical to that used in PHP 7 and earlier, with the following differences:

  • You need to define a visibility level
  • You do not have to explicitly declare the properties in advance
  • You do not need to make assignments in the body of the __construct() method

Here is a bare-bones example of code that uses constructor property promotion:

// /repo/ch01/php8_prop_promo.php
class Test {
    public function __construct(
        public int $id,
        public int $token = 0,
        public string $name = '')
    { }
$test = new Test(999);

When the preceding code block is executed, this is the output:

object(Test)#1 (3) {
  ["id"]=> int(999)
  ["token"]=> int(0)
  ["name"]=> string(0) ""

This shows that an instance of Test type has been created using default values. Now, let's have a look at how this feature might save a substantial amount of coding.

Using property promotion for code reduction

In a conventional OOP PHP class, the following three things need to be done:

  1. Declare the properties, as follows:
    namespace Php7\Image;
    class SingleChar {
        public $text     = '';
        public $fontFile = '';
        public $width    = 100;
        public $height   = 100;
        public $size     = 0;
        public $angle    = 0.00;
        public $textX    = 0;
        public $textY    = 0;
  2. Identify the properties and their data type in the __construct() method signature, as follows:
    const DEFAULT_TX_X = 25;
    const DEFAULT_TX_Y = 75;
    const DEFAULT_TX_SIZE  = 60;
    const DEFAULT_TX_ANGLE = 0;
    public function __construct(
        string $text,
        string $fontFile,
        int $width  = 100,
        int $height = 100,
        int $size   = self::DEFAULT_TX_SIZE,
        float $angle = self::DEFAULT_TX_ANGLE,
        int $textX  = self::DEFAULT_TX_X,
        int $textY  = self::DEFAULT_TX_Y)   
  3. In the body of the __construct() method, assign values to properties, like this:
    {   $this->text     = $text;
        $this->fontFile = $fontFile;
        $this->width    = $width;
        $this->height   = $height;
        $this->size     = $size;
        $this->angle    = $angle;
        $this->textX    = $textX;
        $this->textY    = $textY;
        // other code not shown 

As the number of constructor arguments increases, the amount of work you need to do also increases significantly. When constructor property promotion is applied, the amount of code required to do the same as previously shown is reduced to one-third of the original.

Let's now have a look at the same block of code as shown previously, but rewritten using this powerful new PHP 8 feature:

// /repo/src/Php8/Image/SingleChar.php
// not all code shown
public function __construct(
    public string $text,
    public string $fontFile,
    public int    $width    = 100,
    public int    $height   = 100,
    public int    $size     = self::DEFAULT_TX_SIZE,
    public float   $angle    = self::DEFAULT_TX_ANGLE,
    public int    $textX    = self::DEFAULT_TX_X,
    public int    $textY    = self::DEFAULT_TX_Y)
    { // other code not shown }

Amazingly, what took 24 lines of code in PHP 7 and earlier can be collapsed into eight lines of code using this new PHP 8 feature!

You are completely free to include other code in the constructor. In many cases, however, constructor property promotion takes care of everything normally done in the __construct() method, which means you can literally leave it empty ({ }).

Now, in the next section, you learn about a new feature called attributes.


Have a look at the full SingleChar class for PHP 7 here:

Also, the equivalent PHP 8 class is found here:

For more information on this new feature, have a look at the following: