Storing and retrieving cache in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel cache retrieval code?

Consider this Laravel code snippet that stores and retrieves a cache value. What will be the output when the code runs?

Laravel

<?php
use Illuminate\Support\Facades\Cache;

Cache::put('user_count', 15, 10);
$value = Cache::get('user_count');
echo $value;

A 15

B null

C Throws an exception

D 0

💡 Hint

Think about what Cache::put and Cache::get do in Laravel.

The code stores the value 15 in the cache with the key 'user_count' for 10 seconds. Then it retrieves the value using Cache::get. Since the key exists, it returns 15.

📝 Syntax

intermediate

Which option correctly stores a value in Laravel cache for 5 minutes?

You want to store the string 'hello' in the cache with the key 'greeting' for 5 minutes. Which code snippet is correct?

A Cache::put('greeting', 'hello', 5);

B Cache::put('greeting', 'hello', now()->addMinutes(5));

C Cache::put('greeting', 'hello', 5 * 60);

D Cache::put('greeting', 'hello', '5 minutes');

💡 Hint

Laravel cache expiration can be a DateTime or a number of seconds.

Options B and C are correct. B uses a DateTime instance (now()->addMinutes(5)). C uses 300 seconds (5 * 60 = 5 minutes). Option A uses 5 seconds (too short). Option D uses invalid string syntax.

🔧 Debug

advanced

Why does this Laravel cache retrieval return null?

Given this code, why does Cache::get('session_data') return null?

Laravel

<?php
use Illuminate\Support\Facades\Cache;

Cache::put('session_data', ['id' => 1, 'name' => 'Alice'], 1);
$value = Cache::get('session_data');
// After 2 minutes
$valueAfter = Cache::get('session_data');

A The cache driver does not support storing arrays.

B The cache key was never set, so it returns null.

C The cache expired after 1 second, so after 2 minutes the value is null.

D Cache::get always returns null for arrays.

💡 Hint

Think about the expiration time and when the retrieval happens.

The cache was set to expire after 1 second. Retrieving after 2 minutes means the cache expired and returns null.

🧠 Conceptual

advanced

What happens if you use Cache::remember with a closure in Laravel?

What is the behavior of Cache::remember('key', 10, fn() => expensiveFunction()) in Laravel?

A It always runs expensiveFunction() and ignores the cache.

B It returns the cached value if it exists; otherwise, it runs expensiveFunction(), caches the result for 10 minutes, and returns it.

C It caches the closure itself instead of the result.

D It throws an error because closures cannot be cached.

💡 Hint

Cache::remember is designed to cache the result of the closure.

Cache::remember checks if the key exists. If yes, returns cached value. If no, runs the closure, caches its return value, then returns it.

❓ state_output

expert

What is the output of this Laravel cache increment code?

Given this code, what is the final value of $count after execution?

Laravel

<?php
use Illuminate\Support\Facades\Cache;

Cache::put('count', 5, 10);
Cache::increment('count');
Cache::increment('count', 3);
$count = Cache::get('count');
echo $count;

A Throws an error because increment requires an integer

B 8

C 5

D 9

💡 Hint

Increment adds to the cached value each time.

Initial value is 5. First increment adds 1 (default), second adds 3, total 5 + 1 + 3 = 9.