Registering middleware in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output when a route uses a middleware registered only in the $middlewareGroups array?

Consider a Laravel app where a middleware named CheckAge is registered only inside the web group in app/Http/Kernel.php. If a route uses middleware('CheckAge') directly, what happens?

Laravel

protected $middlewareGroups = [
    'web' => [
        \App\Http\Middleware\CheckAge::class,
        // other middlewares
    ],
];

// Route definition
Route::get('/profile', function () {
    return 'Profile page';
})->middleware('CheckAge');

A The middleware is ignored and the route returns 'Profile page'.

B The middleware runs and the route returns 'Profile page'.

C The middleware runs twice causing unexpected behavior.

D Laravel throws a 'Middleware [CheckAge] not found' error.

💡 Hint

Think about where Laravel looks for middleware when you use the middleware() method with a string.

Middleware registered only inside a group like web cannot be referenced directly by name in routes. Laravel expects middleware used by name to be registered in the $routeMiddleware array. Otherwise, it throws a 'Middleware not found' error.

📝 Syntax

intermediate

Which option correctly registers a middleware named LogRequests for route usage?

You want to register a middleware LogRequests so you can use it in routes like ->middleware('log.requests'). Which registration in app/Http/Kernel.php is correct?

A 'log.requests' => \App\Http\Middleware\LogRequests::class,

B 'LogRequests' => \App\Http\Middleware\LogRequests::class,

C 'logRequests' => \App\Http\Middleware\LogRequests::class,

D 'log_requests' => \App\Http\Middleware\LogRequests::class,

💡 Hint

Middleware keys are case sensitive and usually use dot notation for readability.

The key used in $routeMiddleware must match exactly the string used in the route's middleware method. Using 'log.requests' matches the usage ->middleware('log.requests').

🔧 Debug

advanced

Why does this middleware not run on the route?

Given this Kernel snippet and route, why does the CheckUser middleware not execute?

Laravel

protected $middlewareGroups = [
    'api' => [
        \App\Http\Middleware\CheckUser::class,
    ],
];

Route::get('/data', function () {
    return 'Data';
})->middleware('CheckUser');

A Because middleware groups cannot contain custom middleware.

B Because 'CheckUser' is not registered in $routeMiddleware, Laravel cannot find it by name.

C Because the route is missing the 'api' middleware group in its definition.

D Because the middleware class has a syntax error and fails silently.

💡 Hint

Check where Laravel looks for middleware when you use a string in middleware().

Middleware inside groups like 'api' are applied only when the group is used. Using the middleware name directly requires registration in $routeMiddleware.

❓ state_output

advanced

What is the output after registering middleware in $middleware vs $routeMiddleware?

Consider a middleware Authenticate registered in $middleware array and another middleware LogAccess registered in $routeMiddleware with key 'log.access'. If a route uses ->middleware('log.access'), what middleware run?

Laravel

protected $middleware = [
    \App\Http\Middleware\Authenticate::class,
];

protected $routeMiddleware = [
    'log.access' => \App\Http\Middleware\LogAccess::class,
];

Route::get('/dashboard', function () {
    return 'Dashboard';
})->middleware('log.access');

A Only LogAccess middleware runs; Authenticate is ignored.

B Only Authenticate middleware runs; LogAccess is ignored.

C Both Authenticate and LogAccess middleware run before the route returns 'Dashboard'.

D Neither middleware runs; the route returns 'Dashboard' directly.

💡 Hint

Think about global middleware vs route middleware.

Middleware in $middleware run on every request globally. Middleware in $routeMiddleware run only when assigned to routes. So both run here.

🧠 Conceptual

expert

Which statement about middleware registration and usage is TRUE?

Choose the correct statement about how Laravel middleware registration affects their usage in routes.

A Middleware must be registered in $routeMiddleware to be used by string name in routes.

B Middleware registered only in $middlewareGroups can be used by name in routes without errors.

C Middleware registered in $middleware run only on routes that explicitly list them.

D Middleware registered in $routeMiddleware run globally on all requests.

💡 Hint

Recall the difference between global, group, and route middleware.

Only middleware registered in $routeMiddleware can be referenced by string name in routes. $middleware is global, $middlewareGroups apply to groups of routes.