Meydan okuma - Tasarım desenleri

NotificationChannel { return match($type) { "email" => new EmailChannel(), "sms" => new SmsChannel(), default => throw new InvalidArgumentException(...) }; } } yaz. class NotificationService { private array $observers = []; public function attach(NotificationObserver $o): void { ... } public function notify(string $type, string $message): string { $channel = NotificationFactory::make($type); $result = $channel->send($message); foreach ($this->observers as $o) { $o->onSent($result); } return $result; } } yaz. Sonra demoyu çalıştır.
Örnek çözüm:
<?php
// Ürün API'si + güvenlik + bildirimler: NotificationFactory ve NotificationService yaz

class ProductRepository {
    private PDO $pdo;

    public function __construct(PDO $pdo) {
        $this->pdo = $pdo;
        $this->pdo->exec("CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price INTEGER)");
        $stmt = $this->pdo->prepare("INSERT INTO products (name, price) VALUES (?, ?)");
        $stmt->execute(["Kale", 5]);
        $stmt->execute(["Defter", 15]);
    }

    public function all(): array {
        $rows = $this->pdo->query("SELECT id, name, price FROM products ORDER BY id")->fetchAll(PDO::FETCH_ASSOC);
        return array_map(fn($r) => [
            "id" => (int)$r["id"],
            "name" => $r["name"],
            "price" => (int)$r["price"]
        ], $rows);
    }
}

function handleGet(PDO $pdo): string {
    $repo = new ProductRepository($pdo);
    return json_encode(["products" => $repo->all()], JSON_UNESCAPED_UNICODE);
}

class AuthService {
    private array $users = [];
    private string $csrf = "";

    public function register(string $user, string $pass): void {
        $this->users[$user] = password_hash($pass, PASSWORD_DEFAULT);
    }

    public function login(string $user, string $pass): bool {
        if (!isset($this->users[$user])) return false;
        return password_verify($pass, $this->users[$user]);
    }

    public function csrfToken(): string {
        if ($this->csrf === "") {
            $this->csrf = bin2hex(random_bytes(8));
        }
        return $this->csrf;
    }

    public function applyHeaders(): void {
        header("X-Frame-Options: DENY");
        header("X-Content-Type-Options: nosniff");
    }
}

interface NotificationChannel {
    public function send(string $message): string;
}

class EmailChannel implements NotificationChannel {
    public function send(string $message): string {
        return "E-posta: " . $message;
    }
}

class SmsChannel implements NotificationChannel {
    public function send(string $message): string {
        return "SMS: " . $message;
    }
}

interface NotificationObserver {
    public function onSent(string $log): void;
}

class LogObserver implements NotificationObserver {
    public array $logs = [];
    public function onSent(string $log): void {
        $this->logs[] = $log;
    }
}

class NotificationFactory {
    public static function make(string $type): NotificationChannel {
        return match ($type) {
            "email" => new EmailChannel(),
            "sms" => new SmsChannel(),
            default => throw new InvalidArgumentException("Bilinmeyen kanal"),
        };
    }
}

class NotificationService {
    private array $observers = [];

    public function attach(NotificationObserver $o): void {
        $this->observers[] = $o;
    }

    public function notify(string $type, string $message): string {
        $channel = NotificationFactory::make($type);
        $result = $channel->send($message);
        foreach ($this->observers as $o) {
            $o->onSent($result);
        }
        return $result;
    }
}

// Demo:
$svc = new NotificationService();
$logger = new LogObserver();
$svc->attach($logger);
echo $svc->notify("email", "Sipariş alındı") . "\n";
echo $svc->notify("sms", "Kargo yola çıktı") . "\n";
echo "Log sayısı: " . count($logger->logs) . "\n";