This document discusses hexagonal architecture, an approach to software design that aims to decouple code and make applications independent of external resources. It outlines some issues with traditional MVC architecture, like duplication when additional interfaces are needed. Hexagonal architecture addresses this through dependency injection and interfaces. Core business logic is separated from interfaces, databases can be swapped out by implementing different interfaces, and changes are isolated within layers. The goal is independent, decoupled code that is flexible and adaptable to new requirements and technologies.

1. Hexagonal Architecture
Decouple your code

2. About me
MANEL SELLÉS
Software engineer
at Ulabox
FIBer
@manelselles

3. Hexagonal architecture
Complex
Systems

4. Hexagonal architecture
http://www.slideshare.net/RubnSospedra/learning-from-the-ulabox-stack
Web & apps Integrations & Backoffice Warehouse Delivery
Servers

5. Hexagonal architecture
Complex
Applications

6. Hexagonal architecture

7. Hexagonal architecture
WTF??

8. Hexagonal architecture
Model-View-Controller
(MVC)

9. Hexagonal architecture

10. Hexagonal architecture
class Controller
{
public function index() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
render_html('index_view.php', $someStrangeValue);
}
}

11. Hexagonal architecture
What if I want to access
from command line?

12. Hexagonal architecture
class Controller
{
public function index() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
render_html('index_view.php', $someStrangeValue);
}
}
class CommandLine
{
public function execute() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
print($someStrangeValue);
}
}

13. Hexagonal architecture
What if I want to publish it
to a messaging queue?

14. Hexagonal architecture
class Controller
{
public function index() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
render_html('index_view.php', $someStrangeValue);
}
}
class CommandLine
{
public function execute() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
print($someStrangeValue);
}
}
class QueuePublisher
{
public function publish() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
publish(new Message($someStrangeValue));
}
}

15. Hexagonal architecture
My boss asks me to change
the logic of
$someStrangeValue

16. Hexagonal architecture
class Controller
{
public function index() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
render_html('index_view.php', $someStrangeValue);
}
}
class CommandLine
{
public function execute() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
print($someStrangeValue);
}
}
class QueuePublisher
{
public function publish() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
publish(new Message($someStrangeValue));
}
}

17. Hexagonal architecture
What can we do?
1. Live with duplication?
2. Encapsulate in a service?

18. Hexagonal architecture
Dependency Injection
to the rescue!

19. Hexagonal architecture
class StrangeCalculator
{
public function calculate() {
$someStrangeValue = ...; /** Some operation with data from MySQL **/
return $someStrangeValue;
}
}
class Controller
{
private $strangeCalculator;
public function __construct(StrangeCalculator $strangeCalculator) {
$this->strangeCalculator = $strangeCalculator;
}
public function index() {
render_html('index_view.php', $this->strangeCalculator->calculate());
}
}

20. Hexagonal architecture
class CommandLine
{
private $strangeCalculator;
public function __construct(StrangeCalculator $strangeCalculator) {
$this->strangeCalculator = $strangeCalculator;
}
public function execute() {
print($this->strangeCalculator->calculate());
}
}
class QueuePublisher
{
private $strangeCalculator;
public function __construct(StrangeCalculator $strangeCalculator) {
$this->strangeCalculator = $strangeCalculator;
}
public function publish() {
publish(new Message($this->strangeCalculator->calculate()));
}
}

21. Hexagonal architecture
What if I decide to change
my StrangeCalculator
database?

22. Hexagonal architecture
interface StrangeCalculator
{
public function calculate();
}
class StrangeCalculatorFromMySQL implements StrangeCalculator
{
public function calculate() {
$someStrangeValue = ...; /** get value from google **/
return $someStrangeValue;
}
}
class StrangeCalculatorWithMongoDB implements StrangeCalculator
{
public function calculate() {
$someStrangeValue = ...; /** get value from mongo DB **/
return $someStrangeValue;
}
}

23. Hexagonal architecture
class Controller
{
private $strangeCalculator;
public function __construct(StrangeCalculator $strangeCalculator) {
$this->strangeCalculator = $strangeCalculator;
}
public function index() {
render_html('index_view.php', $this->strangeCalculator->calculate());
}
}
//Use controller with StrangeCalculatorFromMySQL
$strangeCalculatorFromMySQL = new StrangeCalculatorFromMySQL();
new Controller($strangeCalculatorFromMySQL);
//Use controller with StrangeCalculatorWithMongoDB
$strangeCalculatorWithMongoDB = new StrangeCalculatorWithMongoDB();
new Controller($strangeCalculatorWithMongoDB);

24. Hexagonal architecture
Welcome to Hexagonal
Architecture!
akka ports & adapters

25. Hexagonal architecture

26. Thanks
Make your code independent