Low-level caching with Rails.cache - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to write data to the cache with a key.

Ruby on Rails

Rails.cache.[1]("user_1", "John")

Drag options to blanks, or click blank then click option'

Awrite

Bdelete

Cread

Dfetch

Attempts:

3 left

💡 Hint

Common Mistakes

Using read instead of write to store data.

Using fetch when you want to just write without reading.

The write method stores data in the cache under the given key.

2fill in blank

medium

Complete the code to read cached data by key.

Ruby on Rails

user_name = Rails.cache.[1]("user_1")

Drag options to blanks, or click blank then click option'

Afetch

Bwrite

Cread

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using write instead of read to get data.

Using fetch when only reading is needed.

The read method retrieves data from the cache by key.

3fill in blank

hard

Fix the error in the code to fetch cached data or compute and store it.

Ruby on Rails

user_name = Rails.cache.[1]("user_1") { "John" }

Drag options to blanks, or click blank then click option'

Awrite

Bfetch

Cread

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using read which does not accept a block.

Using write which does not read existing data.

The fetch method reads cached data if present; otherwise, it runs the block, stores the result, and returns it.

4fill in blank

hard

Fill both blanks to write data with expiration time in seconds.

Ruby on Rails

Rails.cache.write("session_123", "active", expires_in: [1].[2])

Drag options to blanks, or click blank then click option'

A5

Bminutes

Cseconds

Dhours

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string like '5 seconds' instead of separate number and unit.

Using wrong units like 'hours' when seconds are intended.

The expires_in option sets how long the cache entry lasts. Here, 5 seconds means the data expires quickly.

5fill in blank

hard

Fill all three blanks to fetch cached data with a block and set expiration.

Ruby on Rails

user = Rails.cache.fetch("user_42", expires_in: [1].[2]) { [3] }

Drag options to blanks, or click blank then click option'

A10

Bminutes

CUser.find(42)

Dseconds

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the block code outside the block braces.

Using wrong expiration units or values.

This code fetches user data from cache or runs User.find(42) to get it, caching it for 10 minutes (600 seconds).