Laravel 内核解析：服务容器、门面、服务提供者与中间件管道

// 最核心的两行：绑定 + 解析
$app = app();                       // 获取容器实例
app()->bind('user.service', function ($app) {
    return new UserService($app->make(UserRepository::class));
});
$service = app('user.service');     // 解析

// 1. 简单绑定：每次解析都执行闭包，返回新实例
$this->app->bind(UserRepository::class, function ($app) {
    return new UserRepository($app->make(DatabaseConnection::class));
});

// 2. 单例绑定：首次解析后缓存实例，后续复用
$this->app->singleton(ConfigRepository::class, function ($app) {
    return new ConfigRepository($app['config']);
});

// 3. 实例绑定：直接把已存在的对象放入容器
$this->app->instance('redis', $redisClient);

// 4. 无闭包绑定：让容器自己用反射解析
$this->app->bind(LoggerInterface::class);   // 若类无构造依赖可直接 new

class OrderService
{
    public function __construct(
        private OrderRepository $orders,
        private PaymentGateway $gateway,
    ) {}
}

// 无需任何 bind，直接解析：
$service = app()->make(OrderService::class);
// 容器反射发现需要 OrderRepository、PaymentGateway，
// 再对它们各自反射构造……直到没有依赖为止。

class OrderService
{
    // PHP 8 特性：声明即赋值，容器照样注入
    public function __construct(
        private OrderRepository $orders,
        private PaymentGateway $gateway,
    ) {}
}

// 绑定接口 → 实现
$this->app->bind(OrderRepositoryInterface::class, EloquentOrderRepository::class);

// 别名：字符串别名可以绑定到类名
$this->app->alias(CacheManager::class, 'cache');
$cache = app('cache');          // 与 app(CacheManager::class) 相同

// 在 OrderController 中，OrderRepositoryInterface 用读写分离的读库
$this->app->when(OrderController::class)
          ->needs(OrderRepositoryInterface::class)
          ->give(function ($app) {
              return new ReadReplicaOrderRepository($app['db.replica']);
          });

use Illuminate\Support\Facades\Cache;

Cache::put('user:1', $user, 600);
$user = Cache::get('user:1');

class Cache extends Facade
{
    protected static function getFacadeAccessor()
    {
        return 'cache';   // 容器中绑定的键
    }
}

// Facade 的 __callStatic 核心逻辑（简化）：
public static function __callStatic($method, $args)
{
    $instance = static::getFacadeRoot();       // app('cache')
    return $instance->{$method}(...$args);      // 转发到实例方法
}

use Illuminate\Support\Facades\Cache;

public function test_cache_interaction(): void
{
    Cache::shouldReceive('get')
         ->once()
         ->with('user:1')
         ->andReturn($fakeUser);

    $this->get('/api/user')->assertOk();
}

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use App\Services\Sms\AliyunSmsSender;
use App\Contracts\SmsSender;

class SmsServiceProvider extends ServiceProvider
{
    public function register(): void
    {
        $this->app->singleton(SmsSender::class, AliyunSmsSender::class);
    }

    public function boot(): void
    {
        // 服务已全部注册，可安全使用
        $this->app->make(SmsSender::class)->configureFromConfig();
    }
}

class MetricsProvider extends ServiceProvider
{
    protected $defer = true;

    public function provides()
    {
        return [MetricsCollector::class];
    }

    public function register(): void
    {
        $this->app->singleton(MetricsCollector::class);
    }
}

$pipeline = new Pipeline($app);

$result = $pipeline
    ->send($request)                       // 传递对象
    ->through([ThrottleRequests::class, AuthMiddleware::class])
    ->then(function ($request) {           // 终点：控制器
        return $controller->__invoke($request);
    });

namespace App\Http\Middleware;

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

class SetLocale
{
    public function handle(Request $request, Closure $next): Response
    {
        $locale = $request->header('Accept-Language', 'zh-CN');
        app()->setLocale($locale);        // 前置逻辑

        $response = $next($request);       // 放行到内层

        $response->headers->set('X-Locale', $locale); // 后置逻辑
        return $response;
    }
}

// bootstrap/app.php (Laravel 11)
->withMiddleware(function (Middleware $middleware) {
    $middleware->append(ForceHttps::class);           // 全局追加
    $middleware->web(append: [ShareUserInfo::class]);  // web 分组
    $middleware->alias(['throttle' => ThrottleRequests::class]);
})

require __DIR__.'/../vendor/autoload.php';

$app = require_once __DIR__.'/../bootstrap/app.php';

$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
);

$response->send();
$kernel->terminate($request, $response);

use Illuminate\Http\Request;

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

    public function store(Request $request, int $id): JsonResponse
    {
        $data = $request->validate([...]);
        return response()->json($this->orders->place($data), 201);
    }
}

public function test_order_creation_uses_fake_payment(): void
{
    $this->app->instance(PaymentGateway::class, $fakeGateway);
    // 之后容器解析出的 PaymentGateway 都是 $fakeGateway
}

// ❌ 反模式：业务逻辑里到处解析容器
public function notify(User $user)
{
    app(Notifier::class)->send($user);
}

// ✅ 推荐：构造器注入，依赖显式
public function __construct(private Notifier $notifier) {}

public function notify(User $user)
{
    $this->notifier->send($user);
}

# 列出当前容器中所有绑定（Kernel 层调试）
php artisan tinker

# 在 tinker 里解析并检查
>>> app(CacheManager::class)
>>> app()->getBindings()
>>> app()->getAliases()

php artisan container:debug   # 第三方扩展容器调试命令（若有）