DDD, CQRS, ES, Hexagonal... and Symfony

We talk a lot about various architectural approaches and how to make our projects better when using them to achieve business goals and technical quality. Unfortunately, we don't talk as much about the environment in which we apply those techniques - the framework - and since they represent the crucial part which determines the amount of work, I think we should. In this talk I'd like to show you how Symfony can be used with virtually any kind of approach - DDD, CQRS, Event Sourcing, Hexagonal Architecture, and many more - and how well it fits in each of those use cases. There are no silver bullets, but some tools do a really good job of letting you take control, and Symfony is definitely one of them.

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1. ∙ ∙ in Symfony ∙
2. architectural patterns
3. needs they do
4. it depends™
5. wait
6. don't
7. !==
8. belongs to
9. tools responsibility well fault
10. not the end
11. library
12. don't *
13. Symfony ?
14. good boy framework!
15. clear responsibility boundaries
16. supports
17. like a framework
18. forget included in PHP SPL
19. information flow the architecture
20. composer create-project symfony/skeleton .
21. ├── bin │ └── console ├── composer.json ├── composer.lock ├── config │ ├── bootstrap.php │ ├── bundles.php │ ├── packages │ │ ├── cache.yaml │ │ ├── dev │ │ │ └── routing.yaml │ │ ├── framework.yaml │ │ ├── routing.yaml │ │ └── test │ │ ├── framework.yaml │ │ └── routing.yaml │ ├── routes.yaml │ └── services.yaml ├── public │ └── index.php ├── src │ ├── Controller │ └── Kernel.php ├── symfony.lock ├── var └── vendor
22. ├── bin │ └── console ├── composer.json ├── composer.lock ├── config │ ├── bootstrap.php │ ├── bundles.php │ ├── packages │ │ ├── cache.yaml │ │ ├── dev │ │ │ └── routing.yaml │ │ ├── framework.yaml │ │ ├── routing.yaml │ │ └── test │ │ ├── framework.yaml │ │ └── routing.yaml │ ├── routes.yaml │ └── services.yaml ├── public │ └── index.php ├── src │ ├── Controller │ └── Kernel.php ├── symfony.lock ├── var └── vendor
23. └── src ├── Controller └── Kernel.php
25. └── src ├── Command │ └── GenerateCommand.php ├── Controller │ ├── UserController.php │ └── CarController.php ├── Entity │ ├── User.php │ └── Car.php ├── Form │ ├── UserType.php │ └── CarType.php ├── Manager │ ├── UserManager.php │ └── CarManager.php ├── Repository │ ├── UserRepository.php │ └── CarRepository.php ├── Security │ └── Voter │ ├── UserVoter.php │ └── CarVoter.php ├── Service │ ├── UserService.php │ └── CarService.php └── Kernel.php
26. └── src ├── Command │ └── GenerateCommand.php ├── Controller │ ├── UserController.php │ └── CarController.php ├── Entity │ ├── User.php │ └── Car.php ├── Form │ ├── UserType.php │ └── CarType.php ├── Manager │ ├── UserManager.php │ └── CarManager.php ├── Repository │ ├── UserRepository.php │ └── CarRepository.php ├── Security │ └── Voter │ ├── UserVoter.php │ └── CarVoter.php ├── Service │ ├── UserService.php │ └── CarService.php └── Kernel.php
27. not guilty
28. extremely simplified architectural approaches
29. ports adapters
30. CQRS
31. Domain Driven Design
32. Event Sourcing
33. src └── Shared └── Infrastructure └── SymfonyKernel.php
34. src ├── Account │ ├── Application │ ├── Domain │ └── Infrastructure └── Shared ├── Application ├── Domain └── Infrastructure └── SymfonyKernel.php
35. src ├── Account │ ├── Application │ ├── Domain │ └── Infrastructure └── Shared ├── Application │ └── CommandInterface.php ├── Domain └── Infrastructure ├── SynchronousCommandBus.php ├── CommandBusInterface.php └── SymfonyKernel.php
36. interface CommandBusInterface { public function handle(CommandInterface $command): void; } final class SynchronousCommandBus implements CommandBusInterface { private $handlers; public function map(string $command, callable $handler): void { $this->handlers[$command] = $handler; } public function handle(CommandInterface $command): void { $fqcn = \get_class($command); $handlerNotFound = false === isset($this->handlers[$fqcn]); HandlerNotFoundException::throwWhen($handlerNotFound, $fqcn); call_user_func($this->handlers[$fqcn], $command); } }
37. src ├── Account │ ├── Application │ ├── Domain │ │ ├── Account.php │ │ └── AccountRepositoryInterface.php │ └── Infrastructure └── Shared ├── Application │ └── CommandInterface.php ├── Domain └── Infrastructure ├── SynchronousCommandBus.php ├── CommandBusInterface.php └── SymfonyKernel.php
38. interface AccountRepositoryInterface { public function findById(int $id): Account; } final class Account { /** @var int */ private $id; /** @var string */ private $email; public function __construct(int $id, string $email) { $this->id = $id; $this->email = $email; } }
39. src ├── Account │ ├── Application │ │ ├── AccountQueryInterface.php │ │ ├── SetupAccountCommand.php │ │ └── SetupAccountHandler.php │ ├── Domain │ │ ├── Account.php │ │ └── AccountRepositoryInterface.php │ └── Infrastructure └── Shared ├── Application │ └── CommandInterface.php ├── Domain └── Infrastructure ├── SynchronousCommandBus.php ├── CommandBusInterface.php └── SymfonyKernel.php
40. final class SetupAccountCommand implements CommandInterface { /** @var int */ private $id; /** @var string */ private $email; public function __construct(int $id, string $email) { $this->id = $id; $this->email = $email; } public function getId(): int { return $this->id; } public function getEmail(): string { return $this->email; } }
41. final class SetupAccountHandler { /** @var AccountRepositoryInterface */ private $accounts; public function __construct(AccountRepositoryInterface $accounts) { $this->accounts = $accounts; } public function __invoke(SetupAccountCommand $cmd) { $account = new Account($cmd->getId(), $cmd->getEmail()); $this->accounts->add($account); } }
42. interface AccountQueryInterface { public function findByEmail(EmailValue $email): AccountView; } final class AccountView { /** @var int */ public $id; /** @var string */ public $email; public function __construct(int $id, string $email) { $this->id = $id; $this->email = $email; } }
43. src ├── Account │ ├── Application │ │ ├── AccountQueryInterface.php │ │ ├── SetupAccountCommand.php │ │ └── SetupAccountHandler.php │ ├── Domain │ │ ├── Account.php │ │ └── AccountRepositoryInterface.php │ └── Infrastructure │ ├── AccountController.php │ ├── DoctrineDbalAccountQuery.php │ └── DoctrineOrmAccountRepository.php └── Shared ├── Application │ └── CommandInterface.php ├── Domain └── Infrastructure ├── SynchronousCommandBus.php ├── CommandBusInterface.php └── SymfonyKernel.php
44. final class DoctrineOrmAccountRepository implements AccountRepositoryInterface { /** @var EntityManagerInterface */ private $em; public function __construct(EntityManagerInterface $em) { $this->em = $em; } public function findById(int $id): Account { return $this->em->find(Account::class, $id); } }
45. final class DoctrineDbalAccountQuery implements AccountQueryInterface { /** @var Connection */ private $connection; public function __construct(Connection $connection) { $this->connection = $connection; } public function findByEmail(EmailValue $email): AccountView { $sql = 'SELECT id, email FROM user WHERE email = :email'; $data = $this->connection->exec($sql, ['email' => $email]); return new AccountView($data['id'], $data['email']); } }
46. final class AccountController { // ... public function __construct(CommandBusInterface $bus, RouterInterface $router) { // ... } public function setupAction(Request $request): Response { $id = generateId(); $payload = $request->request->all(); $command = new SetupAccountCommand($id, $payload['email']); $this->bus->handle($command); return new Response(null, Response::HTTP_CREATED, [ 'Location' => $this->router->generate('account.view', [$id]), ]); } }
47. Symfony?
48. account.setup: methods: [POST] path: /accounts controller: account.controller::setupAction
49. parameters: services: _defaults: autowire: true autoconfigure: true App\: resource: '../src/*' exclude: '../src/{DependencyInjection,Entity,Migrations,Tests,Kernel.php}' App\Controller\: resource: '../src/Controller' tags: ['controller.service_arguments']
50. services: _defaults: autowire: false autoconfigure: false public: false
51. account.query: class: Thunder\App\Account\Infrastructure\DoctrineDbalAccountQuery arguments: ['@doctrine.dbal.connection'] account.repository: class: Thunder\App\Account\Infrastructure\DoctrineOrmAccountRepository arguments: ['@doctrine.orm.entity_manager'] account.controller: class: Thunder\App\Account\Infrastructure\AccountController arguments: ['@command_bus', '@routing'] public: true
52. command_bus: class: Thunder\App\Shared\Infrastructure\SynchronousCommandBus arguments: [] calls: - ['map', ['Thunder\App\Account\Application\SetupAccountCommand','@account.setup.handler']] account.setup.handler: class: Thunder\App\Account\Application\AddAccountHandler arguments: ['@account.repository']
53. E S
54. src ├── Account │ ├── Application │ │ ├── AccountQueryInterface.php │ │ ├── SetupAccountCommand.php │ │ └── SetupAccountHandler.php │ ├── Domain │ │ ├── Account.php │ │ ├── AccountWasSetupEvent.php │ │ └── AccountRepositoryInterface.php │ └── Infrastructure │ ├── AccountController.php │ ├── DoctrineDbalAccountQuery.php │ └── DoctrineOrmAccountRepository.php └── Shared ├── Application │ └── CommandInterface.php ├── Domain └── Infrastructure ├── SynchronousCommandBus.php ├── CommandBusInterface.php └── SymfonyKernel.php
55. final class AccountWasSetupEvent { /** @var int */ private $id; /** @var string */ private $email; public function __construct(int $id, string $email) { $this->id = $id; $this->email = $email; } public function getId(): int { return $this->id; } public function getEmail(): string { return $this->email; } }
56. simple, eh?
57. simple !== easy
58. Any questions? ask
59. Resources https://murze.be/hexagonal-architecture https://fideloper.com/hexagonal-architecture https://stackoverflow.com/q/32216408/443341 https://www.slideshare.net/profpv/hexagonal-architecture-in-php https://matthiasnoback.nl/2017/08/layers-ports-and-adapters-part-2-layers https://enterprisecraftsmanship.com/2019/01/31/cqrs-commands-part-domain-model https://blog.octo.com/en/hexagonal-architecture-three-principles-and-an-implementation-example https://herbertograca.com/2017/11/16/explicit-architecture-01-ddd-hexagonal-onion-clean-cqrs-how-i-put-it-all-together/ https://apiumhub.com/tech-blog-barcelona/applying-hexagonal-architecture-symfony-project Images https://unsplash.com/photos/cjNaoIqbWCI (dog) https://unsplash.com/photos/6U-sSfBV-gM (city tower) https://unsplash.com/photos/aSCx7M1E4Vo (foggy forest) https://unsplash.com/photos/h0Vxgz5tyXA (wooden floor)
60. 5 30 2 8 knowledge eternal glory Symfopardy! see you today at 17:00!
63. GENTLEMAN software with manners @tmmx
64. Thanks!