Hexagonal SymfonyMarcello Duarte

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About me

Marcello DuarteSensioLabs

UK

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Why do we care about maintainability?

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Convenience vs Maintainability

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Maintainability is not a thing for the future

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“We cannot manage what we cannot measure”

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“We cannot manage what we cannot measure”

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We cannot manage what we cannot

change

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“A framework is ‘just’ one of the tools to help you develop better and faster” – Symfony documentation

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Faster is not enough

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Growable http

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“Key in making great and growable systems is to

design how its modules communicate

[and not] what their properties and behaviours should be.”

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real procedure Sum (k, l, u, ak) value l, u; integer k, l, u; real ak; begin real S; S := 0; for k := l step 1 until u do S := S + ak; Sum := S; end; x := Sum( i, 1, n, V[i] );

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From Block Structure to OO

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Glyph Class Char (c); Character c; Begin Procedure print; OutChar(c); End;

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Module A Module B

flow of control? source code dependency?

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controller

use case

utility

uses

uses

Naïve Implementation

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!public function updateAction($id) { $em = $this->getDoctrine()->getManager(); $product = $em->getRepository('AcmeStoreBundle:Product')->find($id); ! if (!$product) { throw $this->createNotFoundException( 'No product found for id '.$id ); } ! $product->setName('New product name!'); $em->flush(); ! return $this->redirect($this->generateUrl('homepage')); }

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!public{ $em $product ! ! $product $em! }

Doctrine

RedirectModel

Router

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Module A Polymorphic

Dependency Inversion Principle

Module B

[Martin 02]

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use case

service adapter

utility adapter

service

utility

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Layered Architecture

User Interface

Application

Domain

Infrastructure

[Evans 04]

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“The hexagon is not a hexagon because the number six is important, but rather to allow the people doing the drawing

to have room to insert ports and adapters as they need”

:)

[Cockburn 08]

@_md SensioLabshttp://www.flickr.com/photos/10849858@N00/2696404813

Ports are the interfaces that describe the relationship of your application with the outside world

@_md SensioLabshttp://www.flickr.com/photos/mac_users_guide/3680586328/

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Hexagonal Architecture

your application

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web gui app

your application

user side ports

test adapter

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web gui app

your application

user side ports

test adapter

data side ports

db access

in memory

db

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Dbrest

Logs

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“Architecture is about intent”

[Martin 02]

START WRITING A UNIT TEST FOR THE ENTRY POINT,

BUT INSTEAD OF IMMEDIATELY TRYING TO SOLVE THE PROBLEM, INTENTIONALLY

DEFER WRITING ANY IMPLEMENTATION LOGIC! INSTEAD, BREAK DOWN THE

PROBLEM BY DREAMING UP ALL OF THE OBJECTS YOU WISH YOU HAD

Just

in S

earl

s

KNOW IN ADVANCE WHERE YOU ARE GOING TO PUT CERTAIN

BEHAVIOURS. […] IN SHORT, BEFORE YOU WRITE YOUR FIRST TEST,

YOU HAVE TO "DREAM UP THE [BOUNDARIES] THAT YOU WISH YOU

HAD".U

ncle

Beb

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Dream the feature

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Dream the boundaries

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L&D app !

!

Learning Domain

Google Auth Employees

API

Twitter bootstrap

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Express intent

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<—— Domain<—— Application<—— Delivery Port<—— Persistency Port

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Context also have boundaries

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Controllers depend on use cases

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/** * @Route(service="controllers.skills") */ class SkillsController { private $competencyFinder; private $raterFinder; ! public function __construct(CompetencyFinder $competencyFinder) { $this->competencyFinder = $competencyFinder; } ! /** * @Route("/skills", name="skills") * @Template() * Show the skill for the learners role */ public function indexAction() { return ['competencies' => $this->competencyFinder->findDictionary()]; } }

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Use cases depend on the domain services and ports

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<?php !namespace Inviqa\TeamUp\Skills; !use Inviqa\Learning\Learner; use Inviqa\Learning\Skills\CompetencyDictionaryFinder; !class CompetencyFinder { private $learner; ! private $finder; ! public function __construct(Learner $learner, CompetencyDictionaryFinder $finder) { $this->learner = $learner; $this->finder = $finder; } ! public function findDictionary() { return $this->finder->findByLearnerRole($this->learner->getLearnerRole()); } }

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<?php !namespace Inviqa\Learning\Skills; !use Inviqa\Learning\LearnerRole; !interface CompetencyDictionaryFinder { /** * Gets the dictionary for a particular role * * @param LearnerRole $role * @return \Inviqa\Learning\CompetencyDictionary */ public function findByLearnerRole(LearnerRole $role); }

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Leverage Symfony Event Dispatcher Keep Controller stuff in the controller

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public function onSuccess(Event $event) { $this->flashBag->add('success', 'Project has been created.'); } ! public function onFailure(Event $event) { $this->flashBag->add( 'failure', 'Failed to create project.' . PHP_EOL . $event->get(‘reason') ); }

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And make you controller a listener of your use case

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github.com/MarcelloDuarte/hexagonal-symfony

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Thanks!

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Questions?

joind.in/10781 github.com/MarcelloDuarte/hexagonal-symfony