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

Wrap-Up


Some concepts in the Domain demand Identity — that is, changes to their internal states don't change their own unique identities. We've seen how modeling Identity as a Value Object brings benefits like immutability, in addition to logic for operating the Identity itself. We've also shown several ways of providing Identity, restated in the following pointers:

  • Persistence mechanism: Easy to implement, but you won't have the Identity before persisting the object, which delays and complicates event propagation.
  • Surrogate ID: Some ORMs require an extra field on your Entity to map the Identity with the persisting mechanism.
  • Provided by the client: Sometimes the Identity fits a Domain concept and you can model it inside your Domain.
  • Generated by the application: You can use a library to generate IDs.
  • Generated by a Bounded Context: Probably the most complex strategy. Other Bounded Contexts provide an interface for generating Identities.

We've seen and discussed Doctrine as a persistence mechanism...