无法在Slim Framework控制器__construct（）中执行重定向

I have an application in Slim Framework v3. There are 2 controllers, classes/FrontController.php and classes/AdminController.php.

AdminController.php is for Admin functionality (un-surprisingly!) and the FrontController.php for "public" part of the application.

Various routes have been defined in /index.php which run functions in these controllers - all normal.

What I'm trying to do is write a single piece of code (without repeating it all over) inside AdminController::__construct() such that it will redirect users to FrontController::index() if they try and access any Admin routes via URL manipulation.

The code which I have in my AdminController is like this:

public function __construct(Slim\Container $ci) {
    $this->ci = $ci;
    if (!$this->_isAdmin()) {
        return $this->ci->response->withStatus(302)->withHeader('Location', '/index');
    }
}

This doesn't seem to do anything even though $this->_isAdmin() returns false - I've even tested it by only returning false irrespective of the result the database would return under normal operation. My expectation is that it would redirect at this point, but it instead goes and loads up AdminController::index() if I try and access /admin in the browser.

I'm guessing this is something to do with the fact that the response cannot be manipulated in the constructor? But I'm lost now and not sure how to handle this. Any advice appreciated.

For information the routes in my index.php are like this:

$app->get('/', '\FrontController:index')->setName('/index');
$app->get('/admin', '\AdminController:index');
// many other routes...

You are trying to return an Response object inside an constructor. A constructor is for constructing the object, so the return value does nothing, you should either use middleware for this or make this check in every route method.

$app->get('/admin', '\AdminController:index')->add(function($request, $response, $next) {
    if(user is not admin) {
        return $response->withStatus(302)->withHeader('Location', '/index');
    }
    return $next($request, $response);
});