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

The Observable::create() method versus the Subject class


Apart from creating custom Observables, we know that we can use the Observable::create() static method or an instance of the Subject class to emit items by ourselves, but so far we haven't talked about which one we should choose over the other and why.

As a rule of thumb it's usually better to use Observable::create(). It's not always possible, but it has its advantages.

For the next couple of examples, let's consider that we want to work with an API that implements the following interface. This could be any Facebook/Twitter/WebSocket or system API:

interface RemoteAPI { 
    public function connect($connectionDetails); 
    public function fetch($path, $callback); 
    public function close(); 
} 

Hot/cold Observables and Observable::create()

In the most general sense an Observable is just a function that connects an observer with the producer of values. By producer we understand any source of values that is unrelated...