Cache tags in Laravel - Mini Project: Build & Apply

Using Cache Tags in Laravel

📖 Scenario: You are building a Laravel application that caches different types of data separately. You want to group cached items using tags so you can clear related cache entries easily.

🎯 Goal: Build a Laravel cache example that stores and retrieves data using cache tags, and then clears cache by tag.

📋 What You'll Learn

Create a cache entry with a tag

Set a cache expiration time

Retrieve a cached item using the tag

Clear all cache items with a specific tag

💡 Why This Matters

🌍 Real World

Cache tags help organize cached data by groups, making it easy to clear related cache entries without affecting others. This is useful in apps with multiple data types or modules.

💼 Career

Understanding cache tagging is important for Laravel developers to optimize app performance and manage cache efficiently in real projects.

1

Create a cache entry with a tag

Write code to store the string 'Laravel Cache with Tags' in the cache with the key 'message' using the tag 'framework'. Use the Laravel Cache::tags() method and the put() method.

Laravel

<?php

use Illuminate\Support\Facades\Cache;

// Store 'Laravel Cache with Tags' in cache with key 'message' and tag 'framework'
// Your code here

Hint

Use Cache::tags(['framework'])->put('message', 'Laravel Cache with Tags', 3600); to store the cache with a tag and expiration time of 3600 seconds.

2

Set a cache expiration time

Add a variable called $expiration and set it to 3600 seconds. Then update the cache put() call to use this $expiration variable as the expiration time.

Laravel

<?php

use Illuminate\Support\Facades\Cache;

$expiration = 3600;
// Update the cache put call to use $expiration
// Your code here

Hint

Define $expiration = 3600; and use it as the third argument in put().

3

Retrieve a cached item using the tag

Write code to get the cached value with key 'message' using the tag 'framework'. Store the result in a variable called $cachedMessage. Use the Laravel Cache::tags() method and the get() method.

Laravel

put('message', 'Laravel Cache with Tags', $expiration);

// Retrieve the cached message using tag 'framework'
// Your code here

Hint

Use $cachedMessage = Cache::tags(['framework'])->get('message'); to retrieve the cached item by tag.

4

Clear all cache items with a specific tag

Write code to clear all cache entries with the tag 'framework' using the Laravel Cache::tags() method and the flush() method.

Laravel

put('message', 'Laravel Cache with Tags', $expiration);

$cachedMessage = Cache::tags(['framework'])->get('message');

// Clear all cache with tag 'framework'
// Your code here

Hint

Use Cache::tags(['framework'])->flush(); to clear all cache entries with the tag.

Practice

1. What is the main purpose of using cache tags in Laravel?

easy

A. To group cached items for easy management and selective clearing

B. To encrypt cached data automatically

C. To increase cache storage size

D. To log cache hits and misses

Solution

1. Step 1: Understand cache tags concept

   Cache tags allow grouping of cached items under one or more tags.

2. Step 2: Identify the benefit of grouping

   This grouping helps to clear or manage all related cache items easily by tag.

3. Final Answer:

   To group cached items for easy management and selective clearing -> Option A

4. Quick Check:

   Cache tags = group and manage cache [OK]

Hint: Cache tags group items for easy clearing [OK]

Common Mistakes:

• Thinking tags encrypt data
• Assuming tags increase cache size
• Confusing tags with logging features

2. Which of the following is the correct syntax to store a cache item with a tag in Laravel?

easy

A. Cache::tags('users')->put('user_1', 'John', 3600);

B. Cache::put('user_1', 'John')->tags(['users'], 3600);

C. Cache::put('user_1', 'John', 3600)->tags(['users']);

D. Cache::tags(['users'])->put('user_1', 'John', 3600);

Solution

1. Step 1: Recall Laravel cache tag syntax

   The tags() method accepts an array of tags before calling put().

2. Step 2: Check method chaining order

   The correct order is Cache::tags([...])->put(key, value, time).

3. Final Answer:

   Cache::tags(['users'])->put('user_1', 'John', 3600); -> Option D

4. Quick Check:

   tags() before put() with array [OK]

Hint: Use tags() with array before put() [OK]

Common Mistakes:

• Passing tags after put()
• Using string instead of array in tags()
• Chaining methods in wrong order

3. Given the code below, what will be the output of Cache::tags(['products'])->get('item_1'); after Cache::tags(['products'])->flush(); is called?

Cache::tags(['products'])->put('item_1', 'Book', 600);
Cache::tags(['products'])->flush();
$value = Cache::tags(['products'])->get('item_1');
echo $value ?? 'Not found';

medium

A. Not found

B. CacheException

C. null

D. Book

Solution

1. Step 1: Understand flush() effect on tagged cache

   Calling flush() on a tag clears all cached items under that tag.

2. Step 2: Check retrieval after flush

   After flushing, get('item_1') returns null, so the null coalescing operator outputs 'Not found'.

3. Final Answer:

   Not found -> Option A

4. Quick Check:

   flush() clears tagged cache = 'Not found' [OK]

Hint: flush() clears all tagged cache items [OK]

Common Mistakes:

• Expecting cached value after flush
• Confusing flush() with forget()
• Assuming flush() only clears one item

4. Identify the error in the following Laravel cache tag usage:

Cache::tags('sessions')->put('session_1', 'data', 120);
Cache::tags(['sessions'])->flush();

medium

A. Missing cache driver configuration

B. Using string instead of array in tags() method

C. Calling flush() on tags is not allowed

D. put() method requires a closure

Solution

1. Step 1: Check tags() method argument type

   The tags() method requires an array of tags, not a string.

2. Step 2: Identify the incorrect usage

   Passing a string 'sessions' instead of ['sessions'] causes an error.

3. Final Answer:

   Using string instead of array in tags() method -> Option B

4. Quick Check:

   tags() needs array, not string [OK]

Hint: Always pass array to tags() [OK]

Common Mistakes:

• Passing single string instead of array
• Thinking flush() is disallowed
• Assuming put() needs closure

5. You want to cache user profile data and product data separately but clear both caches together when needed. Which is the best way to use cache tags in Laravel to achieve this?

hard

A. Tag user profiles with ['users'] and products with ['products'], then flush both tags separately

B. Use no tags and clear cache manually by keys

C. Tag both user profiles and products with ['app_data'], then flush this tag to clear all

D. Tag user profiles with ['users'] and products with ['products'], then flush(['users', 'products'])

Solution

1. Step 1: Understand grouping with tags

   To clear multiple cache groups together, use a common tag for both.

2. Step 2: Apply a shared tag

   Tag both user and product caches with a shared tag like 'app_data' to flush all at once.

3. Final Answer:

   Tag both user profiles and products with ['app_data'], then flush this tag to clear all -> Option C

4. Quick Check:

   Shared tag groups caches for joint flush [OK]

Hint: Use shared tag to clear multiple caches together [OK]

Common Mistakes:

• Flushing tags separately instead of shared tag
• Not tagging caches for group clearing
• Trying to flush multiple tags in one call incorrectly