Route middleware in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is route middleware in Laravel?

Route middleware is a way to filter HTTP requests entering your application. It runs code before or after a route is executed to check conditions like authentication or logging.

beginner

How do you apply middleware to a route in Laravel?

You add middleware to a route using the middleware() method in the route definition, for example: Route::get('/dashboard', fn() => 'Dashboard')->middleware('auth');

intermediate

What is the difference between global middleware and route middleware?

Global middleware runs on every HTTP request to your app. Route middleware runs only on specific routes you assign it to.

intermediate

How do you create a custom route middleware in Laravel?

Use php artisan make:middleware MiddlewareName to create it. Then add your logic in the handle method and register it in app/Http/Kernel.php under $routeMiddleware.

intermediate

What happens if a middleware returns a response before the route runs?

The middleware stops the request from reaching the route and sends the middleware's response back to the browser. This is useful for blocking unauthorized access.

Which method is used to assign middleware to a Laravel route?

A applyMiddleware()

B useMiddleware()

C middleware()

D setMiddleware()

The correct method to assign middleware to a route is middleware().

Where do you register custom route middleware in Laravel?

A routes/web.php

B app/Http/Kernel.php

C config/app.php

D app/Providers/RouteServiceProvider.php

Custom route middleware must be registered in the $routeMiddleware array inside app/Http/Kernel.php.

What is the main purpose of route middleware?

A To filter and control access to routes

B To define URL patterns

C To create database migrations

D To style HTML output

Route middleware filters requests and controls access to routes.

If middleware returns a response early, what happens next?

A The route still runs after middleware

B The request is redirected to another route

C The middleware is ignored

D The route is skipped and middleware response is sent

Middleware can stop the request and send its own response without running the route.

Which artisan command creates a new middleware class?

A php artisan make:middleware

B php artisan make:controller

C php artisan make:route

D php artisan make:service

Use php artisan make:middleware to create a new middleware class.

Explain how route middleware works in Laravel and how you apply it to a route.

Think about how you protect pages like a dashboard.

Describe the steps to create and register a custom route middleware in Laravel.

Focus on creation, coding, registration, and usage.

Practice

1. What is the main purpose of route middleware in Laravel?

easy

A. To run code before or after a route handles a request

B. To define database relationships

C. To create views for the application

D. To manage session storage

Solution

1. Step 1: Understand middleware role

   Middleware runs code before or after a route processes a request to add extra logic.

2. Step 2: Compare with other options

   Database relationships, views, and session storage are unrelated to middleware's main role.

3. Final Answer:

   To run code before or after a route handles a request -> Option A

4. Quick Check:

   Middleware = Pre/Post route code [OK]

Hint: Middleware runs code around route handling [OK]

Common Mistakes:

• Confusing middleware with database or view logic
• Thinking middleware manages sessions directly
• Assuming middleware creates HTML views

2. Which of the following is the correct way to apply middleware named auth to a route in Laravel?

easy

A. Route::get('/dashboard', function () {})->middleware('auth');

B. Route::get('/dashboard', function () {}, 'auth');

C. Route::get('/dashboard', function () {})->useMiddleware('auth');

D. Route::get('/dashboard', function () {})->apply('auth');

Solution

1. Step 1: Recall middleware syntax for routes

   Laravel uses ->middleware('name') to assign middleware to a route.

2. Step 2: Check syntax

   Only Route::get('/dashboard', function () {})->middleware('auth'); uses the correct method. Others use non-existent methods like apply() and useMiddleware() or pass invalid extra arguments.

3. Final Answer:

   Route::get('/dashboard', function () {})->middleware('auth'); -> Option A

4. Quick Check:

   Correct middleware method = middleware() [OK]

Hint: Use ->middleware('name') after route definition [OK]

Common Mistakes:

• Using non-existent methods like useMiddleware or apply
• Placing middleware before route method incorrectly
• Forgetting to pass middleware name as string

3. Given the route group below, what middleware will be applied to the /profile route?

Route::middleware(['auth', 'verified'])->group(function () {
    Route::get('/profile', function () {
        return 'User Profile';
    });
});

medium

A. No middleware applied

B. Only 'verified' middleware

C. Only 'auth' middleware

D. Both 'auth' and 'verified' middleware

Solution

1. Step 1: Understand middleware groups

   Middleware array passed to middleware() applies all listed middleware to routes inside the group.

2. Step 2: Check the group middleware list

   The group uses ['auth', 'verified'], so both middleware run on /profile route.

3. Final Answer:

   Both 'auth' and 'verified' middleware -> Option D

4. Quick Check:

   Group middleware = all listed middleware [OK]

Hint: Middleware array applies all listed middleware [OK]

Common Mistakes:

• Assuming only first middleware applies
• Thinking middleware arrays override each other
• Ignoring middleware groups and only checking route

4. Identify the error in this middleware assignment:

Route::get('/settings', function () {
    return 'Settings';
})->middleware(auth);

medium

A. Middleware cannot be applied to GET routes

B. Middleware must be registered in the controller

C. Middleware name should be a string

D. Middleware should be applied using ->useMiddleware()

Solution

1. Step 1: Check middleware argument type

   Middleware names must be passed as strings, e.g., 'auth', not bare words.

2. Step 2: Verify other options

   Middleware can be applied to GET routes; no need for controller registration here; useMiddleware() is invalid.

3. Final Answer:

   Middleware name should be a string -> Option C

4. Quick Check:

   Middleware name = string in quotes [OK]

Hint: Always quote middleware names as strings [OK]

Common Mistakes:

• Passing middleware name without quotes
• Thinking middleware only works on POST routes
• Using non-existent middleware methods

5. You want to apply a middleware named checkAge only to routes under /admin but exclude it from /admin/login. Which is the best way to do this in Laravel?

hard

A. Apply checkAge middleware globally and remove it from /admin/login

B. Apply checkAge middleware to the group /admin and add except for /admin/login

C. Apply checkAge middleware only to /admin/login route

D. Apply checkAge middleware to all routes except /admin

Solution

1. Step 1: Understand middleware group usage

   Applying middleware to a route group covers all routes inside it.

2. Step 2: Use 'except' to exclude specific routes

   Laravel allows excluding routes from middleware using 'except' in middleware definition or group.

3. Step 3: Evaluate options

   Apply checkAge middleware to the group /admin and add except for /admin/login correctly applies middleware to /admin group and excludes /admin/login. Others apply middleware incorrectly or globally.

4. Final Answer:

   Apply checkAge middleware to the group /admin and add except for /admin/login -> Option B

5. Quick Check:

   Group middleware + except route = correct approach [OK]

Hint: Use middleware group with except to exclude routes [OK]

Common Mistakes:

• Applying middleware only to excluded route
• Applying middleware globally without exclusions
• Excluding entire /admin instead of just /admin/login