We already know about Route Groups but we haven’t used them yet in a meaningful way. The main purpose of Route Groups is to be able to easily assign a Middleware to a collection of Routes.

Middlewares must implement Centum\Interfaces\Router\MiddlewareInterface.

Middlewares only require one public method:

  • check(Centum\Interfaces\Http\RequestInterface $request): bool

By returning false in a Middleware, the Router will ignore that Group and then continue checking the following Groups.

A common use case for Middlewares is to use different Routes for visitors that are logged in and visitors that are not. First, we need to create a Middleware to check if the user is logged in:

namespace App\Web\Middlewares;

use App\Auth;
use Centum\Interfaces\Http\RequestInterface;
use Centum\Interfaces\Router\MiddlewareInterface;

class IsUserMiddleware implements MiddlewareInterface
    public function __construct(
        protected readonly Auth $auth
    ) {

    public function check(RequestInterface $request): bool
        return $this->auth->isLoggedIn();

(The App\Auth class is not shown and is just used as an example.)

When creating the Group in the Router, we simply assign the first parameter as a MiddlewareInterface object. We can also use Centum\Router\Middleware\InverseMiddleware to inverse the result of an existing Middleware so that one Middleware can be used for opposing Groups:

use App\Web\Middlewares\IsUserMiddleware;
use Centum\Router\Middleware\InverseMiddleware;

/** @var IsUserMiddleware $isUserMiddleware */

$userGroup = $router->group($isUserMiddleware);

$userGroup->get("/account", AccountController::class, "user");

$guestGroup = $router->group(
    new InverseMiddleware($isUserMiddleware)

$guestGroup->get("/account", AccountController::class, "guest");

Now, in a Controller, we can use two different methods, user() and guest(), for these two groups:

namespace App\Web\Controllers;

use Centum\Http\Response;
use Centum\Interfaces\Http\ResponseInterface;
use Centum\Interfaces\Router\ControllerInterface;

class AccountController implements ControllerInterface
    public function user(): ResponseInterface
        return new Response("This visitor is logged in.");

    public function guest(): ResponseInterface
        return new Response("This visitor is logged out.");

Callback Middleware

Centum\Router\Middleware\CallbackMiddleware can be used to create a custom Middleware without creating a class for it:

use Centum\Interfaces\Http\RequestInterface;
use Centum\Router\Middleware\CallbackMiddleware;

    new CallbackMiddleware(
        function (RequestInterface $request): bool {
            return $request->getMethod() === "POST";