Book Image

PHP Reactive Programming

By : Martin Sikora
Book Image

PHP Reactive Programming

By: Martin Sikora

Overview of this book

Reactive Programming helps us write code that is concise, clear, and readable. Combining the power of reactive programming and PHP, one of the most widely used languages, will enable you to create web applications more pragmatically. PHP Reactive Programming will teach you the benefits of reactive programming via real-world examples with a hands-on approach. You will create multiple projects showing RxPHP in action alone and in combination with other libraries. The book starts with a brief introduction to reactive programming, clearly explaining the importance of building reactive applications. You will use the RxPHP library, built a reddit CLI using it, and also re-implement the Symfony3 Event Dispatcher with RxPHP. You will learn how to test your RxPHP code by writing unit tests. Moving on to more interesting aspects, you will implement a web socket backend by developing a browser game. You will learn to implement quite complex reactive systems while avoiding pitfalls such as circular dependencies by moving the RxJS logic from the frontend to the backend. The book will then focus on writing extendable RxPHP code by developing a code testing tool and also cover Using RxPHP on both the server and client side of the application. With a concluding chapter on reactive programming practices in other languages, this book will serve as a complete guide for you to start writing reactive applications in PHP.
Table of Contents (18 chapters)
PHP Reactive Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Anonymous operators


We've been using the lift() method to use custom operators in Observable chains a lot. In RxPHP v1, it's also the only way to implement custom operators. This method takes as a parameter the so called operator factory, which is a callable that returns an instance of the operator we want to use. This method is called every time we subscribe, so it might be called just once in total.

When using operators, we're making use of PHP's magic __invoke() method that allows us to use any object just as if it were a function.

Let's consider this simple example that shows the __invoke() method:

// func_01.php 
class MyClass { 
    public function __invoke($a, $b) { 
        return $a * $b; 
    } 
} 
$obj = new MyClass(); 
var_dump($obj(3, 4)); 

We make an instance of MyClass that we used as if it was a regular function with $obj(3,4). If we run this example, we'll get the correct result:

$ php func_01.php 
int(12)

Operators in RxPHP use the same...