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 doOn*() operators


In the previous chapter, we've used the map() operator a couple of times to just print to the console what's happening inside our Observable chains. However, this isn't very convenient. The map() operator always needs to return a value that is passed further down the chain, and it can catch only onNext signals.

That's why RxPHP has a couple of operators with the common prefix doOn*:

  • doOnNext()doOnError()doOnCompleted(): Each of these operators takes a callable as a parameter that is executed when they receive their respective signal

  • doOnEach(): This operator takes an instance of ObserverInterface as a parameter and executes its handlers for each signal

So these operators are very similar to the methods subscribeCallback() and subscribe(). The biggest advantage is in the way doOn* operators work internally. They never modify the value going through and just execute our callables, which is ideal for quickly debugging Observable chains or to perform side-effects without...