Cache invalidation strategies in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the cache expiration time to 60 seconds.

Rest API

cache.set('user_data', data, timeout=[1])

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

A600

B60

C6

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting timeout to 0 disables caching.

Using too large timeout causes stale data.

The timeout parameter defines how long the cache stores data. Setting it to 60 means the cache expires after 60 seconds.

2fill in blank

medium

Complete the code to invalidate the cache for the key 'user_data'.

Rest API

cache.[1]('user_data')

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Aupdate

Brefresh

Cdelete

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using set instead of delete.

Using update which modifies but does not remove.

To remove cached data, you use the delete method with the cache key.

3fill in blank

hard

Fix the error in the code to invalidate cache after updating user info.

Rest API

def update_user(user_id, new_info):
    save_to_db(user_id, new_info)
    cache.[1](f'user_{user_id}')

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Adelete

Bget

Cset

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using set which overwrites cache without new data.

Using get which only reads cache.

After updating the database, you must delete the cache entry to avoid stale data.

4fill in blank

hard

Fill both blanks to create a cache key with user ID and set cache with 120 seconds timeout.

Rest API

cache_key = f'user_[1]'
cache.set(cache_key, user_data, timeout=[2])

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Aid

B120

Cuser_id

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Using id instead of user_id which may not be defined.

Setting timeout to 60 instead of 120.

The cache key uses the variable user_id to identify the user. The timeout is set to 120 seconds for cache expiration.

5fill in blank

hard

Fill all three blanks to implement cache invalidation after updating user profile and then set new cache.

Rest API

def update_profile(user_id, profile):
    db.update(user_id, profile)
    cache.[1](f'user_[2]')
    cache.set(f'user_[3]', profile, timeout=300)

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

Adelete

Buser_id

Cid

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using set instead of delete to remove old cache.

Mixing id and user_id causing key mismatch.

After updating the database, delete the old cache using the user_id key, then set new cache with the updated profile and a 300 seconds timeout.