Laravel Solutions: รูปแบบขั้นสูง การ Debug และคำถามสัมภาษณ์งาน 2026

// Service class encapsulating order business logic

namespace App\Services;

use App\Models\Order;
use App\Models\User;
use App\Exceptions\InsufficientStockException;
use App\Jobs\SendOrderConfirmationEmail;
use Illuminate\Support\Facades\DB;

class OrderService
{
    public function __construct(
        private InventoryService $inventory,
        private PaymentService $payment
    ) {}

    /**
     * Create an order with full validation and side effects
     *
     * @throws InsufficientStockException
     */
    public function createOrder(User $user, array $items, string $paymentMethod): Order
    {
        // Validate stock availability before starting transaction
        foreach ($items as $item) {
            if (!$this->inventory->hasStock($item['product_id'], $item['quantity'])) {
                throw new InsufficientStockException($item['product_id']);
            }
        }

        return DB::transaction(function () use ($user, $items, $paymentMethod) {
            // Create order record
            $order = $user->orders()->create([
                'status' => 'pending',
                'total' => $this->calculateTotal($items),
            ]);

            // Attach order items
            foreach ($items as $item) {
                $order->items()->create($item);
                $this->inventory->decrementStock($item['product_id'], $item['quantity']);
            }

            // Process payment
            $this->payment->charge($user, $order->total, $paymentMethod);
            $order->update(['status' => 'paid']);

            // Queue confirmation email
            SendOrderConfirmationEmail::dispatch($order);

            return $order;
        });
    }

    private function calculateTotal(array $items): int
    {
        return collect($items)->sum(fn($item) => $item['price'] * $item['quantity']);
    }
}

// Controller delegating to service class

namespace App\Http\Controllers;

use App\Http\Requests\CreateOrderRequest;
use App\Services\OrderService;
use Illuminate\Http\JsonResponse;

class OrderController extends Controller
{
    public function __construct(
        private OrderService $orderService
    ) {}

    public function store(CreateOrderRequest $request): JsonResponse
    {
        $order = $this->orderService->createOrder(
            $request->user(),
            $request->validated('items'),
            $request->validated('payment_method')
        );

        return response()->json(['order_id' => $order->id], 201);
    }
}

// Interface defining the contract

namespace App\Repositories\Contracts;

use App\Models\User;
use Illuminate\Support\Collection;

interface UserRepositoryInterface
{
    public function findById(int $id): ?User;
    public function findByEmail(string $email): ?User;
    public function getActiveUsers(): Collection;
    public function getUsersWithRecentOrders(int $days = 30): Collection;
    public function create(array $data): User;
    public function update(User $user, array $data): User;
}

// Eloquent implementation of the repository

namespace App\Repositories;

use App\Models\User;
use App\Repositories\Contracts\UserRepositoryInterface;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Cache;

class EloquentUserRepository implements UserRepositoryInterface
{
    public function findById(int $id): ?User
    {
        return Cache::remember(
            "user.{$id}",
            now()->addMinutes(10),
            fn() => User::find($id)
        );
    }

    public function findByEmail(string $email): ?User
    {
        return User::where('email', $email)->first();
    }

    public function getActiveUsers(): Collection
    {
        return User::where('status', 'active')
            ->orderBy('name')
            ->get();
    }

    public function getUsersWithRecentOrders(int $days = 30): Collection
    {
        return User::whereHas('orders', function ($query) use ($days) {
            $query->where('created_at', '>=', now()->subDays($days));
        })
        ->with(['orders' => fn($q) => $q->latest()->limit(5)])
        ->get();
    }

    public function create(array $data): User
    {
        $user = User::create($data);
        Cache::forget("user.{$user->id}");
        return $user;
    }

    public function update(User $user, array $data): User
    {
        $user->update($data);
        Cache::forget("user.{$user->id}");
        return $user->fresh();
    }
}

// Binding interface to implementation

namespace App\Providers;

use App\Repositories\Contracts\UserRepositoryInterface;
use App\Repositories\EloquentUserRepository;
use Illuminate\Support\ServiceProvider;

class RepositoryServiceProvider extends ServiceProvider
{
    public function register(): void
    {
        $this->app->bind(
            UserRepositoryInterface::class,
            EloquentUserRepository::class
        );
    }
}

// Telescope configuration for different environments

return [
    'enabled' => env('TELESCOPE_ENABLED', true),

    // Only record slow queries in production
    'query' => [
        'slow' => env('TELESCOPE_SLOW_QUERY_THRESHOLD', 100), // milliseconds
    ],

    // Prune old entries to manage database size
    'storage' => [
        'database' => [
            'connection' => env('DB_CONNECTION', 'mysql'),
            'chunk' => 1000,
        ],
    ],
];

// Custom filtering for Telescope entries

namespace App\Providers;

use Laravel\Telescope\IncomingEntry;
use Laravel\Telescope\Telescope;
use Laravel\Telescope\TelescopeApplicationServiceProvider;

class TelescopeServiceProvider extends TelescopeApplicationServiceProvider
{
    public function register(): void
    {
        Telescope::night();

        $this->hideSensitiveRequestDetails();

        // Filter out noise in production
        Telescope::filter(function (IncomingEntry $entry) {
            // Always record exceptions and slow queries
            if ($entry->isException()) {
                return true;
            }

            if ($entry->isSlowQuery()) {
                return true;
            }

            // Skip health check endpoints
            if ($entry->isRequest() && str_starts_with($entry->content['uri'] ?? '', '/health')) {
                return false;
            }

            // Skip static asset requests
            if ($entry->isRequest() && preg_match('/\.(css|js|png|jpg|svg)$/', $entry->content['uri'] ?? '')) {
                return false;
            }

            // Record everything in local environment
            if ($this->app->environment('local')) {
                return true;
            }

            // Production: only record failures and slow operations
            return $entry->isFailedRequest()
                || $entry->isFailedJob()
                || $entry->hasMonitoredTag();
        });
    }

    protected function hideSensitiveRequestDetails(): void
    {
        // Hide sensitive data from Telescope UI
        Telescope::hideRequestParameters(['password', 'password_confirmation', 'token']);
        Telescope::hideRequestHeaders(['authorization', 'cookie']);
    }
}

// Automatic resolution: container reads type hints and builds dependencies
public function __construct(OrderService $service)
{
    // $service is automatically instantiated and injected
}

// Manual binding for interfaces or complex setup
$this->app->bind(PaymentGateway::class, function ($app) {
    return new StripeGateway(
        config('services.stripe.key'),
        config('services.stripe.secret')
    );
});

// Singleton: same instance throughout the request
$this->app->singleton(MetricsCollector::class, function ($app) {
    return new MetricsCollector(
        $app->make(Cache::class)
    );
});

// Simple transaction with automatic rollback on exception
DB::transaction(function () {
    $user = User::create(['email' => 'test@example.com']);
    $user->profile()->create(['bio' => 'New user']);
    // If profile creation fails, user creation rolls back
});

// Manual transaction control for complex flows
DB::beginTransaction();

try {
    $order = Order::create($data);
    PaymentGateway::charge($order->total);

    DB::commit();
} catch (PaymentFailedException $e) {
    DB::rollBack();
    throw $e;
}

// Nested transactions use savepoints
DB::transaction(function () {
    User::create(['email' => 'outer@test.com']);

    DB::transaction(function () {
        // This creates a savepoint
        Profile::create(['user_id' => 1]);
    });
    // Inner failure only rolls back to savepoint
});

// Custom middleware checking team membership

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

class EnsureTeamMember
{
    public function handle(Request $request, Closure $next, string $role = 'member'): Response
    {
        $team = $request->route('team');

        if (!$request->user()->belongsToTeam($team)) {
            abort(403, 'You are not a member of this team.');
        }

        if ($role === 'admin' && !$request->user()->isTeamAdmin($team)) {
            abort(403, 'Admin access required.');
        }

        return $next($request);
    }
}

// Applying middleware to routes

Route::middleware(['auth', 'team.member:admin'])->group(function () {
    Route::get('/teams/{team}/settings', [TeamController::class, 'settings']);
    Route::put('/teams/{team}/settings', [TeamController::class, 'updateSettings']);
});

// Problem: 101 queries for 100 articles
$articles = Article::all();
foreach ($articles as $article) {
    echo $article->author->name; // Each access triggers a query
}

// Solution: eager load with 2 queries total
$articles = Article::with('author')->get();
foreach ($articles as $article) {
    echo $article->author->name; // No additional queries
}

// Nested eager loading for complex relationships
$articles = Article::with([
    'author.profile',
    'comments' => fn($query) => $query->latest()->limit(5),
    'comments.user',
    'tags',
])->get();

use Illuminate\Database\Eloquent\Model;

public function boot(): void
{
    Model::preventLazyLoading(!$this->app->isProduction());
}

// Single-purpose action class

namespace App\Actions;

use App\Models\User;
use App\Notifications\WelcomeNotification;
use Illuminate\Support\Facades\Hash;

class CreateUserAction
{
    public function execute(array $data): User
    {
        $user = User::create([
            'name' => $data['name'],
            'email' => $data['email'],
            'password' => Hash::make($data['password']),
        ]);

        $user->notify(new WelcomeNotification());

        return $user;
    }
}

// Usage in controller
public function store(RegisterRequest $request, CreateUserAction $action)
{
    $user = $action->execute($request->validated());
    return redirect()->route('dashboard');
}

// Usage in command
public function handle(CreateUserAction $action)
{
    $user = $action->execute([
        'name' => $this->argument('name'),
        'email' => $this->argument('email'),
        'password' => $this->argument('password'),
    ]);
    $this->info("Created user: {$user->id}");
}

// Usage in test
public function test_user_creation(): void
{
    $action = new CreateUserAction();
    $user = $action->execute([
        'name' => 'Test User',
        'email' => 'test@example.com',
        'password' => 'password',
    ]);

    $this->assertDatabaseHas('users', ['email' => 'test@example.com']);
}

// Event class carrying order data

namespace App\Events;

use App\Models\Order;
use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class OrderPlaced
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public function __construct(
        public Order $order
    ) {}
}

// Queued listener for email

namespace App\Listeners;

use App\Events\OrderPlaced;
use App\Notifications\OrderConfirmationNotification;
use Illuminate\Contracts\Queue\ShouldQueue;

class SendOrderConfirmation implements ShouldQueue
{
    public function handle(OrderPlaced $event): void
    {
        $event->order->user->notify(
            new OrderConfirmationNotification($event->order)
        );
    }
}

// Another listener for the same event

namespace App\Listeners;

use App\Events\OrderPlaced;
use App\Services\AnalyticsService;
use Illuminate\Contracts\Queue\ShouldQueue;

class UpdateInventoryAnalytics implements ShouldQueue
{
    public function __construct(
        private AnalyticsService $analytics
    ) {}

    public function handle(OrderPlaced $event): void
    {
        foreach ($event->order->items as $item) {
            $this->analytics->recordSale(
                $item->product_id,
                $item->quantity,
                $event->order->created_at
            );
        }
    }
}

// Dispatching the event
OrderPlaced::dispatch($order);

// Or using the event helper
event(new OrderPlaced($order));