Book Image

Domain-Driven Design in PHP

By : Keyvan Akbary, Carlos Buenosvinos, Christian Soronellas
Book Image

Domain-Driven Design in PHP

By: Keyvan Akbary, Carlos Buenosvinos, Christian Soronellas

Overview of this book

Domain-Driven Design (DDD) has arrived in the PHP community, but for all the talk, there is very little real code. Without being in a training session and with no PHP real examples, learning DDD can be challenging. This book changes all that. It details how to implement tactical DDD patterns and gives full examples of topics such as integrating Bounded Contexts with REST, and DDD messaging strategies. In this book, the authors show you, with tons of details and examples, how to properly design Entities, Value Objects, Services, Domain Events, Aggregates, Factories, Repositories, Services, and Application Services with PHP. They show how to apply Hexagonal Architecture within your application whether you use an open source framework or your own.
Table of Contents (24 chapters)
Title Page
Credits
Foreword
About the Authors
Acknowledgments
www.PacktPub.com
Customer Feedback
Dedication
Preface
14
Bibliography
15
The End

Modeling Events


In order to describe your business Domain accurately, you'll have to work closely with Domain Experts and define the Ubiquitous Language. This requires crafting Domain concepts using Domain Events, Entities, Value Objects, and so on. When modeling Events, name them and their properties according to the Ubiquitous Language, in the Bounded Context where they originated. If an Event is the result of executing a command operation on an Aggregate, the name is usually derived from the command that was executed. It's important that the Event name reflects the past nature of the occurrence.

Let's consider our user registration feature; the Domain Event needs to represent it. The following code shows a minimal interface for a base Domain Event:

interface DomainEvent 
{ 
    /** 
     * @return DateTimeImmutable
     */
     public function occurredOn(); 
}

As you can see, the minimum information required is a DateTimeImmutable, which is necessary in order to know when the Event happened...