Route Groups

As an app grows, you'll often have several routes that share the same URL prefix — for example, every route under /api or every admin route under /admin. Slim lets you collect these related routes into a route group so the shared prefix (and any shared middleware) is written once instead of repeated on every route.

Creating a Group

Call $app->group() with the common prefix and a callback. Inside the callback you define routes on the $group object instead of $app — Slim automatically prepends the group's prefix to each one.

<?php
$app->group('/api', function ($group) {

    $group->get('/status', function ($request, $response) {
        $response->getBody()->write('OK');
        return $response;
    });

});

The route above is reachable at /api/status — the /api prefix came entirely from the group, so it never has to be typed again inside the callback.

Applying Middleware to a Whole Group

Just like a single route, a group can have middleware attached with ->add(). This runs the middleware for every route inside that group — a common use case is requiring authentication for all /admin routes without adding the check to each one individually.

<?php
$requireAdmin = function ($request, $handler) {
    // Check session, token, etc. before letting the request continue
    if (!isset($_SESSION['is_admin'])) {
        throw new \Slim\Exception\HttpForbiddenException($request);
    }
    return $handler->handle($request);
};

$app->group('/admin', function ($group) {
    $group->get('/dashboard', function ($request, $response) {
        $response->getBody()->write('Admin dashboard');
        return $response;
    });
})->add($requireAdmin);

Worked Example: Grouping a REST Resource

Grouping shines when a single resource — like users — needs several HTTP methods (GET, POST, PUT, DELETE). Instead of repeating '/api/users' on every line, the prefix is declared once.

<?php
$app->group('/api/users', function ($group) {

    // GET /api/users - list all users
    $group->get('', function ($request, $response) {
        return $response;
    });

    // POST /api/users - create a user
    $group->post('', function ($request, $response) {
        return $response;
    });

    // PUT /api/users/{id} - update one user
    $group->put('/{id}', function ($request, $response, $args) {
        return $response;
    });

    // DELETE /api/users/{id} - remove one user
    $group->delete('/{id}', function ($request, $response, $args) {
        return $response;
    });

});

Four routes, one resource, one prefix declared a single time. Read together, this block reads almost like documentation of everything the /api/users endpoint can do.

Why Bother Grouping?