Cookie handling in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel cookie retrieval code?

Consider this Laravel controller method that tries to read a cookie named 'user_id'. What will be the output if the cookie does not exist?

Laravel

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class CookieController extends Controller
{
    public function showUserId(Request $request)
    {
        $userId = $request->cookie('user_id', 'guest');
        return response()->json(['user_id' => $userId]);
    }
}

A {"user_id":null}

B {"user_id":""}

C {"user_id":"guest"}

D Throws an exception because cookie 'user_id' is missing

💡 Hint

Check the second parameter of the cookie() method in the Request object.

The cookie() method on the Request object returns the cookie value if it exists. If it does not, it returns the default value provided as the second argument. Here, 'guest' is the default, so the output JSON will have 'user_id' set to 'guest'.

📝 Syntax

intermediate

Which option correctly sets a cookie in Laravel with a 10-minute expiration?

You want to set a cookie named 'theme' with value 'dark' that expires in 10 minutes. Which code snippet correctly does this?

A return response('Set theme')->cookie('theme', 'dark', 10);

B return response('Set theme')->cookie('theme', 'dark', now()->addMinutes(10));

C return response('Set theme')->cookie('theme', 'dark', 600);

D return response('Set theme')->cookie('theme', 'dark', '10m');

💡 Hint

The third parameter is the number of minutes until expiration.

In Laravel, the cookie() method's third parameter is the duration in minutes. So passing 10 sets the cookie to expire in 10 minutes. Passing a string like '10m' is invalid.

🔧 Debug

advanced

Why does this Laravel code fail to delete the cookie?

This code tries to delete a cookie named 'session_id' but the cookie remains in the browser. What is the reason?

Laravel

<?php

return response('Delete cookie')->cookie('session_id', '', -1);

A Negative expiration time is invalid and causes Laravel to ignore the cookie.

B The cookie path or domain does not match the original cookie, so deletion fails.

C Setting the cookie value to empty string does not delete it; must use null instead.

D Cookies cannot be deleted via response; must be deleted client-side with JavaScript.

💡 Hint

Cookies are deleted by setting expiration in the past but path and domain must match.

To delete a cookie, Laravel sets it with an expiration time in the past. However, if the path or domain differs from the original cookie, the browser will not delete it. This is a common cause of cookie deletion failure.

❓ state_output

advanced

What is the value of the cookie after this Laravel middleware runs?

This middleware adds a cookie named 'visited' with value 'yes' on the first request. What will be the cookie value on the second request?

Laravel

<?php

namespace App\Http\Middleware;

use Closure;

class CheckVisited
{
    public function handle($request, Closure $next)
    {
        if (!$request->cookie('visited')) {
            $response = $next($request);
            return $response->cookie('visited', 'yes', 60);
        }
        return $next($request);
    }
}

A On second request, cookie 'visited' has value 'yes'.

B On second request, cookie 'visited' is null because middleware does not set it again.

C On second request, middleware throws an error because cookie is missing.

D On second request, cookie 'visited' has value 'no'.

💡 Hint

Cookies set in response are sent to browser and included in next request.

On the first request, the cookie 'visited' is not present, so middleware sets it with value 'yes'. The browser stores it and sends it back on the second request, so the cookie exists with value 'yes'.

🧠 Conceptual

expert

Which statement about Laravel cookie encryption is true?

Laravel encrypts cookies by default. Which of these statements correctly describes this behavior?

A Cookies are encrypted only if the app is in production environment.

B Cookies must be manually encrypted before setting them in Laravel responses.

C Laravel does not encrypt cookies; encryption must be handled by the developer.

D Cookies are encrypted automatically unless added to the 'except' list in the EncryptCookies middleware.

💡 Hint

Check the EncryptCookies middleware behavior in Laravel.

Laravel automatically encrypts all cookies except those listed in the $except array of the EncryptCookies middleware. This ensures cookie data is secure by default.

Practice

1. What is the primary purpose of cookies in Laravel applications?

easy

A. To manage database connections

B. To execute server-side scripts

C. To store small pieces of data on the user's browser

D. To style the web pages dynamically

Solution

1. Step 1: Understand what cookies do

   Cookies store small data on the user's browser to remember information between requests.

2. Step 2: Identify Laravel's use of cookies

   Laravel uses cookies to save user preferences or session data on the client side.

3. Final Answer:

   To store small pieces of data on the user's browser -> Option C

4. Quick Check:

   Cookies = store data on browser [OK]

Hint: Cookies save small data on browser, not server tasks [OK]

Common Mistakes:

• Confusing cookies with server-side scripts
• Thinking cookies manage database
• Assuming cookies control page styles

2. Which Laravel method is used to set a cookie that will be sent with the next response?

easy

A. Cookie::get()

B. Cookie::send()

C. Cookie::set()

D. Cookie::queue()

Solution

1. Step 1: Recall Laravel cookie setting method

   Laravel uses Cookie::queue() to add cookies to the outgoing response.

2. Step 2: Differentiate from other methods

   Cookie::get() reads cookies, Cookie::set() and Cookie::send() are not valid Laravel methods.

3. Final Answer:

   Cookie::queue() -> Option D

4. Quick Check:

   Set cookie = Cookie::queue() [OK]

Hint: Use Cookie::queue() to set cookies in Laravel [OK]

Common Mistakes:

• Using Cookie::get() to set cookies
• Assuming Cookie::set() exists
• Confusing sending with setting cookies

3. What will be the output of the following Laravel code snippet?

Cookie::queue('user', 'Alice', 10);
$value = Cookie::get('user');
echo $value;

medium

A. null

B. Alice

C. 10

D. Error: Undefined method

Solution

1. Step 1: Understand Cookie::queue() behavior

   Cookie::queue() schedules the cookie to be sent with the next response, but it is not immediately available in the current request.

2. Step 2: Check Cookie::get() timing

   Since the cookie is not yet set in the current request, Cookie::get('user') returns null.

3. Final Answer:

   null -> Option A

4. Quick Check:

   Cookie::get() before response = null [OK]

Hint: Queued cookies appear next request, not current one [OK]

Common Mistakes:

• Expecting immediate cookie availability
• Confusing cookie value with expiration time
• Assuming Cookie::queue() sets cookie instantly

4. Identify the error in this Laravel code snippet for deleting a cookie:

Cookie::queue(Cookie::forget('session_id'));

medium

A. Cookie::forget() should not be inside Cookie::queue()

B. Cookie::forget() is the correct way to delete a cookie

C. Cookie::queue() cannot be used with Cookie::forget()

D. The cookie name must be an array, not a string

Solution

1. Step 1: Understand deleting cookies in Laravel

   Laravel deletes cookies by queuing a forget command using Cookie::queue(Cookie::forget('name')).

2. Step 2: Verify syntax correctness

   This syntax is correct and is the recommended way to delete cookies in Laravel.

3. Final Answer:

   Cookie::forget() is the correct way to delete a cookie -> Option B

4. Quick Check:

   Delete cookie = Cookie::queue(Cookie::forget()) [OK]

Hint: Use Cookie::queue(Cookie::forget()) to delete cookies [OK]

Common Mistakes:

• Trying to delete cookie without queue
• Passing array instead of string cookie name
• Thinking Cookie::forget() alone deletes cookie

5. You want to set a cookie named theme with value dark that expires in 60 minutes and then immediately retrieve it in the same request. Which approach correctly handles this in Laravel?

hard

A. Set the cookie with Cookie::queue() and store the value in a variable to use immediately

B. Use Cookie::set('theme', 'dark', 60) and then Cookie::get('theme')

C. Use Cookie::queue('theme', 'dark', 60) and then Cookie::get('theme') immediately

D. Set cookie in response headers manually and read from Cookie::get()

Solution

1. Step 1: Understand cookie availability timing

   Cookies set with Cookie::queue() are sent with the response and not available in the current request.

2. Step 2: Use a variable to hold the value for immediate use

   To use the cookie value immediately, store it in a variable before queuing the cookie.

3. Final Answer:

   Set the cookie with Cookie::queue() and store the value in a variable to use immediately -> Option A

4. Quick Check:

   Immediate use = store value before Cookie::queue() [OK]

Hint: Store value in variable before queuing cookie for immediate use [OK]

Common Mistakes:

• Expecting Cookie::get() to return queued cookie immediately
• Using non-existent Cookie::set() method
• Trying to read cookie before response sent