When Easy Is Hard

...and when hard is easy. Building great applications in PHP is easy - with frameworks like Symfony, Laravel, Yii - it is easier than ever. But the easier you try to make developing applications, the harder it becomes to keep developing one continuously. In my talk I will discuss what easy and hard means at different stages of the project and how we
can make it easier for ourselves to deliver software that matters.

Presented at PHP London meetup http://phplondon.org/2015/03/when-easy-is-hard/

Transcript

1. WHEN EASY IS HARD 12 Mar 2015
2. Marek Matulka Software Engineer at SensioLabsUK @super_marek
3. #Symfony_Live @SensioLabsUK
4. Take it easy!
5. Framework
7. Convenience
9. © http://www.yiiframework.com/tour/
10. <?php namespace App\Http\Controllers; use App\Http\Controllers\Controller; class UserController extends Controller { /** * Show the profile for the given user. * * @param int $id * @return Response */ public function showProfile($id) { return view('user.profile', ['user' => User::findOrFail($id)]); } }
11. <?php namespace Acme\ConferenceBundle\Controller; use Symfony\Bundle\FrameworkBundle\Controller\Controller; use Symfony\Component\HttpFoundation\Response; class RegistrationController extends Controller { public function registerAction($id) { $conference = $this->getDoctrine() ->getRepository('AcmeConferenceBundle:Conference') ->find($id); $this->get('acme_conference.enrolment.service') ->enrol($conference, $this->getUser())) { return new Response('Success!'); } }
12. Cost
13. price speed quality
14. © http://the-language-corner.com/noticias/wp-content/uploads/2015/01/academia-ingl%C3%A9s-en-Madrid.jpg Phase 1 completed!
15. Let’s grow!
16. New features
17. <?php namespace Acme\ConferenceBundle\Controller; use Symfony\Bundle\FrameworkBundle\Controller\Controller; class RegistrationController extends Controller { public function registerAction($id) { $conference = $this->getDoctrine() ->getRepository('AcmeConferenceBundle:Conference')->find($id); if ( $enrolment = $this->get('acme_conference.enrolment.service') ->enrol($conference, $this->getUser()) ) { $em = $this->getDoctrine()->getEntityManager(); $em->persist($enrolment); $em->flush(); $this->get('acme_conference.notification.service') ->notify($this->getUser(), 'success'); return $this->redirect('registration_successful') } return $this->redirect('registration_failed'); } } © http://warrenmars.com/
18. Difficult to maintain
19. © http://www.smosh.com/smosh-pit/memes/20-best-i-didnt-choose-thug-life-memes
20. It takes longer to add new features
21. Yummy spaghetti code! © http://momeefriendsli.com/2013/04/16/dinner-and-a-book/
22. …and there are no tests!
23. No one wants to touch it
24. Let’s rewrite it!
26. not so happy customer © https://channelinstincts.files.wordpress.com/2014/01/unhappy-customer.jpg
27. price speed quality
28. price speed sustainability
29. Do you expect the plumber to “apply the workaround” to your leaking pipe? © http://www.asbestosjustice.co.uk/wp-content/uploads/2014/11/jobs-to-consider-7-plumber-1093362-TwoByOne.jpg
30. What has happened?
31. What has happened? - too close to the framework - no separation of concerns - mixed layers - no tests!
32. delivered features time Features delivered over time
33. How to avoid?
34. Forget the framework!
35. Decouple your code
36. Decoupled code - improves readability - can be reused - easy to maintain - easy to change
37. Let’s do it!
38. Global scope is a smell! Avoid hidden dependencies
39. class RegistrationController { public function registerAction($id) { $learner = Session::getUser(); $conference = Conference::findOrFail($id); Enrolment::enrolLearnerInConference($learner, $conference); Mail::send('emails.welcome', array('key' => 'value'), function($message) use ($learner, $conference) { $message->to($learner->email(), $learner->name()) ->subject('Thanks for registering for '.$conference->name().'!'); } ); } }
40. Inject only what you need
41. class RegistrationController { public function __construct( Enrolment $enrolment, Learner $learner, Notifier $notifier ) { $this->enrolment = $enrolment; $this->learner = $learner; $this->notifier = $notifier; } public function registerAction(Conference $conference) { $enrolment = $this->enrolment->enrolLearnerInConference($this->learner, $conference); $this->notifier->successfulEnrolment($enrolment); } }
42. Don’t mix layers
43. class RegistrationController { public function __construct( EnrolmentHandler $enrolmentHandler, Learner $learner ) { $this->enrolmentHandler = $enrolmentHandler; $this->learner = $learner; } public function registerAction(Conference $conference) { $this->enrolmentHandler->handle( new EnrolLearnerInConference($this->learner, $conference); ); } }
44. class RegistrationController { public function __construct( EnrolmentHandler $enrolmentHandler, Learner $learner ) { $this->enrolmentHandler = $enrolmentHandler; $this->learner = $learner; } public function registerAction(Conference $conference) { $this->enrolmentHandler->handle( new EnrolLearnerInConference($this->learner, $conference); ); } }
45. class RegistrationController { public function registerAction($id) { $learner = Session::getUser(); $conference = Conference::findOrFail($id); Enrolment::enrolLearnerInConference($learner, $conference); Mail::send('emails.welcome', array('key' => 'value'), function($message) use ($learner, $conference) { $message->to($learner->email(), $learner->name()) ->subject('Thanks for registering for '.$conference->name().'!'); } ); } }
46. class EnrolmentHandler { public function __construct(EnrolmentRepository $enrolmentRepository, Mailer $mailer) { $this->repository = $enrolmentRepository; $this->mailer = $mailer; } public function handle(EnrolLearnerInConference $enrolmentCommand) { $enrolment = $enrolmentCommand->execute(); $this->repository>save($enrolment); $this->mailer->send('emails.welcome', array('key' => 'value'), function($message) use ($enrolment) { $message->to($enrolment->learner()->email(), $enrolment->learner()->name()) ->subject('Thanks for registering for '.$enrolment->conference->name().'!'); }); }
47. Invert dependencies
48. class EnrolmentHandler { public function __construct(EnrolmentRepository $enrolmentRepository, Mailer $mailer) { $this->repository = $enrolmentRepository; $this->mailer = $mailer; } public function handle(EnrolLearnerInConference $enrolmentCommand) { $enrolment = $enrolmentCommand->execute(); $this->repository>save($enrolment); $this->mailer->send('emails.welcome', array('key' => 'value'), function($message) use ($enrolment) { $message->to($enrolment->learner()->email(), $enrolment->learner()->name()) ->subject('Thanks for registering for '.$enrolment->conference->name().'!'); }); }
49. class EnrolmentHandler { public function __construct( EnrolmentRepository $enrolmentRepository, EnrolmentNotifier $notifier ) { $this->repository = $enrolmentRepository; $this->notifier = $notifier; } public function handle(EnrolLearnerInConference $enrolmentCommand) { if ($enrolment = $enrolmentCommand->execute()) { $this->repository->save($enrolment); $this->notifier->successfulEnrolment($enrolment); } } }
50. interface EnrolmentNotifier { /** * @param Enrolment $enrolment * * @throws FaildToNotify */ public function successfulEnrolment(Enrolment $enrolment); }
51. interface EnrolmentRepository { /** * @param integer $id * @return Enrolment */ public function findOneById($id); /** * @param Enrolment $enrolment */ public function save(Enrolment $enrolment); }
52. EnrolmentRepository DoctrineEnrolmentRepository InMemoryEnrolmentRepositor y EntityManager Dependency Inversion InMemoryRepository
53. Clean Code
54. Layered Architecture
55. User Interface Application Domain Infrastructure
56. Clean Architecture by Robert C. Martin
57. Entities Use Cases Controllers Web
58. Entities Use Cases Controllers Web Framework Drivers Interface Adapters Application Business Rules Enterprise Business Rules
59. aka Ports & Adapters Hexagonal Architecture
60. UI Adapter Log Adapter Data Storage Adapter Domain External Data Adapter
61. UI Adapter Log Adapter Data Storage Adapter Domain External Data Adapter UI client port log adapter port persistence layer port data provider port
62. UI Adapter Monolog Test Adapter NullLogger Doctrine InMemory Domain Facebook API Mock API
63. Why bother?
64. Why bother writing clean code? - decoupled - reusable - testable - maintainable - changeable
65. Sustainable!
66. class EnrolmentHandler { public function __construct( EnrolmentRepository $enrolmentRepository, EnrolmentNotifier $notifier ) { $this->repository = $enrolmentRepository; $this->notifier = $notifier; } public function handle(EnrolLearnerInConference $enrolmentCommand) { if ($enrolment = $enrolmentCommand->execute()) { $this->repository->save($enrolment); $this->notifier->successfulEnrolment($enrolment); } } }
67. class DoctrineEnrolmentRepository implements EnrolmentRepository { public function __construct(EntityManager $entityManager) { $this->em = $entityManager; } public function findOneById($id) { return $this->em->find(Enrolment::class, $id); } public function save(Enrolment $enrolment) { $this->em->persist($enrolment); $this->em->flush($enrolment); } }
68. class InMemoryEnrolmentRepository implements EnrolmentRepository { public function __construct() { $this->repository = new InMemoryRepository(); } public function findOneById($id) { return $this->repository->findById($id); } public function save(Enrolment $enrolment) { $this->repository->save($enrolment); } }
69. (five more classes to write!) Hard!
70. delivered features time Features delivered over time
71. Recap
72. It’s your choice
73. and make the changes hard Start the easy way
74. and make the changes easy Start the hard way
75. “Everything is hard before it is easy” - Goethe
76. Questions?
77. Thank you! https://speakerdeck.com/super_marek @super_marek