Storing and retrieving cache in Laravel - Mini Project: Build & Apply

Storing and retrieving cache in Laravel

📖 Scenario: You are building a Laravel application that needs to store some data temporarily to speed up repeated requests. Caching helps by saving data so the app does not have to fetch or compute it every time.

🎯 Goal: Learn how to store a value in Laravel cache and then retrieve it later using Laravel's cache facade.

📋 What You'll Learn

Create a cache key and value to store

Set a cache expiration time

Store the value in cache using Laravel's Cache facade

Retrieve the cached value using the same key

💡 Why This Matters

🌍 Real World

Caching is used in web apps to speed up repeated data access and reduce database load.

💼 Career

Understanding Laravel caching is important for backend developers to optimize app performance.

1

Create cache key and value

Create two variables: $cacheKey with the value 'user_count' and $cacheValue with the value 150.

Laravel

# Your code here

Hint

Use simple variable assignment in PHP.

2

Set cache expiration time

Create a variable called $cacheMinutes and set it to 10 to represent cache expiration time in minutes.

Laravel

<?php
$cacheKey = 'user_count';
$cacheValue = 150;
// Set cache expiration time in minutes
# Your code here

Hint

Use a simple integer variable for minutes.

3

Store value in cache

Use Laravel's Cache facade to store $cacheValue in cache with key $cacheKey for $cacheMinutes minutes. Write the line: Cache::put($cacheKey, $cacheValue, $cacheMinutes);

Laravel

<?php
$cacheKey = 'user_count';
$cacheValue = 150;
$cacheMinutes = 10;
// Store value in cache
# Your code here

Hint

Use the put method on the Cache facade with key, value, and minutes.

4

Retrieve value from cache

Retrieve the cached value using Cache::get($cacheKey) and store it in a variable called $cachedUserCount.

Laravel

<?php
use IlluminateSupportFacadesCache;

$cacheKey = 'user_count';
$cacheValue = 150;
$cacheMinutes = 10;
Cache::put($cacheKey, $cacheValue, $cacheMinutes);
// Retrieve cached value
# Your code here

Hint

Use the get method on Cache facade with the cache key.

Practice

1. What does the Cache::put('key', 'value', 60) method do in Laravel?

easy

A. Stores 'value' permanently in cache without expiration

B. Retrieves 'value' from cache with 'key' and expires in 60 seconds

C. Deletes the cache entry with 'key' after 60 minutes

D. Stores 'value' in cache under 'key' for 60 minutes

Solution

1. Step 1: Understand Cache::put method

   The Cache::put method stores data in the cache with a key and expiration time in minutes.

2. Step 2: Analyze the parameters

   Here, 'key' is the cache key, 'value' is the data stored, and 60 means it expires after 60 minutes.

3. Final Answer:

   Stores 'value' in cache under 'key' for 60 minutes -> Option D

4. Quick Check:

   Cache::put stores with expiration = A [OK]

Hint: Cache::put stores with minutes expiry, not seconds [OK]

Common Mistakes:

• Confusing expiration time units (seconds vs minutes)
• Thinking Cache::put retrieves data
• Assuming Cache::put stores data permanently

2. Which of the following is the correct syntax to retrieve a cached value with a default fallback in Laravel?

easy

A. Cache::get('key', 'default')

B. Cache::retrieve('key', 'default')

C. Cache::fetch('key', 'default')

D. Cache::find('key', 'default')

Solution

1. Step 1: Identify Laravel cache retrieval method

   Laravel uses Cache::get to retrieve cached data safely.

2. Step 2: Check method parameters

   The second parameter is the default value returned if the key is not found.

3. Final Answer:

   Cache::get('key', 'default') -> Option A

4. Quick Check:

   Cache::get with default = A [OK]

Hint: Use Cache::get to retrieve with default fallback [OK]

Common Mistakes:

• Using non-existent methods like retrieve or fetch
• Forgetting the default fallback parameter
• Using Cache::put instead of Cache::get

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

Cache::put('count', 5, 10);
$value = Cache::get('count', 0);
echo $value;

medium

A. 0

B. null

C. 5

D. Error

Solution

1. Step 1: Store value in cache

   The code stores the integer 5 under the key 'count' with expiration 10 minutes.

2. Step 2: Retrieve value from cache

   Then it retrieves 'count' with default 0. Since the key exists, it returns 5.

3. Final Answer:

   5 -> Option C

4. Quick Check:

   Cache::get returns stored value if exists = B [OK]

Hint: Cache::get returns stored value, not default if key exists [OK]

Common Mistakes:

• Assuming default value is always returned
• Confusing expiration time with immediate deletion
• Expecting null or error instead of stored value

4. Identify the error in this Laravel cache usage:

Cache::put('user', 'Alice');
$value = Cache::get('user');
echo $value;

medium

A. Cache::put requires expiration time as third argument

B. Cache::get requires a default value parameter

C. Cache::put key must be numeric

D. Cache::get cannot be used without Cache::forever

Solution

1. Step 1: Check Cache::put usage

   Cache::put requires three parameters: key, value, and expiration time in minutes.

2. Step 2: Identify missing expiration

   The code misses the expiration time, so it will cause an error or unexpected behavior.

3. Final Answer:

   Cache::put requires expiration time as third argument -> Option A

4. Quick Check:

   Cache::put needs expiration time = D [OK]

Hint: Always provide expiration time with Cache::put unless using forever [OK]

Common Mistakes:

• Omitting expiration time in Cache::put
• Thinking Cache::get always needs default
• Believing keys must be numeric

5. You want to store a user's settings permanently in cache and then remove them later. Which sequence of Laravel cache methods is correct?

hard

A. Cache::store('settings', $data); Cache::remove('settings');

B. Cache::forever('settings', $data); Cache::forget('settings');

C. Cache::put('settings', $data, 0); Cache::delete('settings');

D. Cache::save('settings', $data); Cache::clear('settings');

Solution

1. Step 1: Store data permanently

   Use Cache::forever to store data without expiration.

2. Step 2: Remove cached data

   Use Cache::forget to delete the cached key when needed.

3. Final Answer:

   Cache::forever('settings', $data); Cache::forget('settings'); -> Option B

4. Quick Check:

   Permanent store + forget = C [OK]

Hint: Use forever to store permanently, forget to delete [OK]

Common Mistakes:

• Using wrong method names like delete or remove
• Passing 0 as expiration to put for permanent storage
• Confusing Cache::store or Cache::save as valid methods