Book Image

PHP 7 Programming Cookbook

By : Doug Bierer
Book Image

PHP 7 Programming Cookbook

By: Doug Bierer

Overview of this book

PHP 7 comes with a myriad of new features and great tools to optimize your code and make your code perform faster than in previous versions. Most importantly, it allows you to maintain high traffic on your websites with low-cost hardware and servers through a multithreading web server. This book demonstrates intermediate to advanced PHP techniques with a focus on PHP 7. Each recipe is designed to solve practical, real-world problems faced by PHP developers like yourself every day. We also cover new ways of writing PHP code made possible only in version 7. In addition, we discuss backward-compatibility breaks and give you plenty of guidance on when and where PHP 5 code needs to be changed to produce the correct results when running under PHP 7. This book also incorporates the latest PHP 7.x features. By the end of the book, you will be equipped with the tools and skills required to deliver efficient applications for your websites and enterprises.
Table of Contents (22 chapters)
PHP 7 Programming Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Implementing the Pub/Sub design pattern


The Publish/Subscribe (Pub/Sub) design pattern often forms the basis of software event-driven programming. This methodology allows asynchronous communications between different software applications, or different software modules within a single application. The purpose of the pattern is to allow a method or function to publish a signal when an action of significance has taken place. One or more classes would then subscribe and take action if a certain signal has been published.

Example of such actions are when the database is modified, or when a user has logged in. Another common use for this design pattern is when an application delivers news feeds. If an urgent news item has been posted, the application would publish this fact, allowing client subscribers to refresh their news listings.

How to do it...

  1. First, we define our publisher class, Application\PubSub\Publisher. You'll notice that we are making use of two useful Standard PHP Library (SPL) interfaces...