ポートとアダプターの概要

ヘキサゴンの考え方

ポートはインターフェース

<?php
// Driven (outbound) port: the core needs to persist users
interface UserRepository
{
    public function byId(UserId $id): ?User;
    public function save(User $user): void;
}

駆動ポートと被駆動ポート

<?php
// Driving (inbound) port — the public capability of the core
interface RegisterUser
{
    public function handle(string $email, string $plainPassword): UserId;
}

コアが駆動ポートを実装する

<?php
final class RegisterUserService implements RegisterUser
{
    public function __construct(
        private UserRepository $users,
        private PasswordHasher $hasher,
        private Clock $clock,
    ) {}

    public function handle(string $email, string $plain): UserId {
        if ($this->users->byEmail($email)) {
            throw new EmailAlreadyTaken($email);
        }
        $user = User::register(
            $email,
            $this->hasher->hash($plain),
            $this->clock->now()
        );
        $this->users->save($user);
        return $user->id();
    }
}

被駆動アダプター

<?php
final class PdoUserRepository implements UserRepository
{
    public function __construct(private PDO $pdo) {}

    public function byId(UserId $id): ?User {
        $stmt = $this->pdo->prepare('SELECT * FROM users WHERE id = ?');
        $stmt->execute([(string) $id]);
        $row = $stmt->fetch(PDO::FETCH_ASSOC);
        return $row ? User::fromRow($row) : null;
    }
    public function save(User $user): void {
        // INSERT ... ON CONFLICT UPDATE
    }
}

駆動アダプター

<?php
// CLI driving adapter
final class RegisterUserCommand
{
    public function __construct(private RegisterUser $register) {}

    public function run(array $argv): int {
        [$email, $password] = array_slice($argv, 1);
        $id = $this->register->handle($email, $password);
        fwrite(STDOUT, "Created user $id\n");
        return 0;
    }
}

テスト用のインメモリアダプター

<?php
final class FixedClock implements Clock {
    public function __construct(private DateTimeImmutable $t) {}
    public function now(): DateTimeImmutable { return $this->t; }
}
final class PlainHasher implements PasswordHasher {
    public function hash(string $p): string { return 'h:' . $p; }
}

$service = new RegisterUserService(
    new InMemoryUsers(),
    new PlainHasher(),
    new FixedClock(new DateTimeImmutable('2026-01-01'))
);
echo 'wired OK', PHP_EOL;

アダプターは翻訳するが、判断しない

1つのポート、多数のアダプター

<?php
interface Notifier { public function send(string $to, string $msg): void; }

final class CompositeNotifier implements Notifier {
    /** @param Notifier[] $channels */
    public function __construct(private array $channels) {}
    public function send(string $to, string $msg): void {
        foreach ($this->channels as $c) $c->send($to, $msg);
    }
}

$notifier = new CompositeNotifier([new EmailNotifier(), new SmsNotifier()]);
echo 'composed', PHP_EOL;

六角形アーキテクチャをフォルダーに対応付ける

六角形アーキテクチャ全体をテストする

<?php
// Acceptance test: real use case, fake driven adapters, no I/O
$users = new InMemoryUsers();
$service = new RegisterUserService($users, new PlainHasher(),
    new FixedClock(new DateTimeImmutable('2026-01-01')));

$id = $service->handle('dev@coddykit.com', 'pw');

assert($users->byId($id) !== null);
echo 'acceptance: user persisted via in-memory adapter', PHP_EOL;

簡単な確認

まとめ