Cache tags in Laravel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are cache tags in Laravel?

Cache tags let you group cached items under named tags. This helps you clear or manage related cache entries together easily.

beginner

How do you store a cache item with a tag in Laravel?

Use the Cache::tags(['tagName'])->put('key', 'value', $seconds); method to save an item with a tag.

beginner

How can you clear all cache items with a specific tag?

Call Cache::tags(['tagName'])->flush(); to remove all cache entries under that tag.

intermediate

Why use cache tags instead of normal cache keys?

Tags let you group related cache items. This makes it easy to clear or update all related items at once, improving cache management.

intermediate

Which cache drivers support cache tags in Laravel?

Drivers like Redis and Memcached support cache tags. File and database drivers do not support tags.

Which Laravel method adds tags to a cache item?

A Cache::tags(['tag'])->put('key', 'value', $seconds);

B Cache::putWithTags('key', 'value', ['tag'], $seconds);

C Cache::tag('tag')->store('key', 'value');

D Cache::addTags('tag')->save('key', 'value');

The correct syntax to add tags is Cache::tags(['tag'])->put('key', 'value', $seconds);

What does Cache::tags(['users'])->flush() do?

A Deletes the 'users' tag but keeps cache items.

B Removes only one cache item with the 'users' tag.

C Flushes the entire cache store.

D Clears all cache items with the 'users' tag.

Calling flush() on a tag removes all cache items associated with that tag.

Which cache driver does NOT support cache tags in Laravel?

A Redis

B Memcached

C File

D Database

File and database cache drivers do not support cache tags in Laravel.

Why are cache tags useful?

A They encrypt cache data automatically.

B They group related cache items for easy management.

C They speed up cache retrieval by indexing keys.

D They backup cache data to disk.

Cache tags group related items so you can clear or update them together.

How do you retrieve a cached item with a tag?

A Cache::getTagged('tag', 'key');

B Cache::getWithTag('tag', 'key');

C Cache::tags(['tag'])->get('key');

D Cache::tag('tag')->fetch('key');

Use Cache::tags(['tag'])->get('key') to get a cached item stored with a tag.

Explain how cache tags work in Laravel and why they are helpful.

Think about grouping related things to manage them easily.

Describe the steps to store, retrieve, and clear cache items using tags in Laravel.

Focus on the Cache::tags() method chain.

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