Cache framework configuration in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the cache backend to use the local memory cache.

Django

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.[1].LocMemCache',
        'LOCATION': 'unique-snowflake',
    }
}

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

Amemcached

Blocmem

Cfilebased

Dredis

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'filebased' instead of 'locmem' for local memory cache.

Using 'memcached' without proper setup.

The correct backend for local memory caching in Django is locmem.

2fill in blank

medium

Complete the code to set the cache timeout to 300 seconds.

Django

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
        'LOCATION': 'unique-snowflake',
        'TIMEOUT': [1],
    }
}

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

A300

B0

C60

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Setting TIMEOUT to None disables expiration, not 300 seconds.

Using 0 means cache never expires, which is different.

The TIMEOUT setting defines how many seconds the cache will keep data. 300 seconds means 5 minutes.

3fill in blank

hard

Fix the error in the cache backend path to use Memcached.

Django

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.[1].MemcachedCache',
        'LOCATION': '127.0.0.1:11211',
    }
}

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

Afilebased

Bredis

Clocmem

Dmemcached

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'locmem' backend for Memcached configuration.

Using 'filebased' backend for Memcached.

The correct backend path for Memcached is memcached.

4fill in blank

hard

Fill both blanks to configure Redis cache backend with a specific location and timeout.

Django

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.[1].RedisCache',
        'LOCATION': '[2]',
        'TIMEOUT': 500,
    }
}

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

Aredis

B127.0.0.1:6379

Cmemcached

Dlocmem

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'memcached' backend with Redis location.

Using 'locmem' backend for Redis.

Redis backend uses 'redis' and the location is usually the Redis server address like '127.0.0.1:6379'.

5fill in blank

hard

Fill all three blanks to create a file-based cache configuration with a directory and no timeout.

Django

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.[1].FileBasedCache',
        'LOCATION': '[2]',
        'TIMEOUT': [3],
    }
}

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

Afilebased

B/var/tmp/django_cache

CNone

Dlocmem

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'locmem' backend for file-based cache.

Setting timeout to 0 instead of None for no expiration.

File-based cache backend is 'filebased', location is a directory path, and 'None' means cache never expires.

Practice

1. What is the main purpose of configuring the CACHES setting in Django?

easy

A. To define the database connection details

B. To tell Django where and how to store temporary data for faster access

C. To set the URL routing rules

D. To configure user authentication methods

Solution

1. Step 1: Understand the role of caching

   Caching stores temporary data to speed up repeated requests by avoiding repeated work.

2. Step 2: Identify what CACHES configures

   The CACHES setting tells Django which backend to use and where to store cached data.

3. Final Answer:

   To tell Django where and how to store temporary data for faster access -> Option B

4. Quick Check:

   Cache config = store temp data [OK]

Hint: Cache config sets storage for temporary data [OK]

Common Mistakes:

• Confusing cache with database settings
• Thinking cache controls URL routing
• Mixing cache with authentication settings

2. Which of the following is the correct way to define a simple in-memory cache backend in Django's CACHES setting?

easy

A. 'default': {'BACKEND': 'django.core.cache.backends.locmem.LocMemCache'}

B. 'default': {'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache', 'LOCATION': '/var/tmp/django_cache'}

C. 'default': {'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache', 'LOCATION': '127.0.0.1:11211'}

D. 'default': {'BACKEND': 'django.core.cache.backends.db.DatabaseCache', 'LOCATION': 'my_cache_table'}

Solution

1. Step 1: Identify the in-memory cache backend

   The in-memory cache backend in Django is LocMemCache, which stores cache in local memory.

2. Step 2: Match the correct syntax

   'default': {'BACKEND': 'django.core.cache.backends.locmem.LocMemCache'} correctly sets BACKEND to django.core.cache.backends.locmem.LocMemCache without needing a LOCATION.

3. Final Answer:

   'default': {'BACKEND': 'django.core.cache.backends.locmem.LocMemCache'} -> Option A

4. Quick Check:

   In-memory cache = LocMemCache [OK]

Hint: LocMemCache is in-memory, no location needed [OK]

Common Mistakes:

• Adding LOCATION for LocMemCache unnecessarily
• Confusing file-based or DB cache for in-memory
• Using wrong backend string casing

3. Given this Django cache configuration snippet, what will be the cache backend used?

 CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.memcached.PyMemcacheCache',
        'LOCATION': '127.0.0.1:11211',
    }
}

medium

A. File-based cache storing data in /var/tmp

B. Local memory cache inside the Django process

C. Database cache storing data in a DB table

D. Memcached cache using PyMemcache client on localhost

Solution

1. Step 1: Read the BACKEND value

   The backend is set to django.core.cache.backends.memcached.PyMemcacheCache, which uses Memcached with the PyMemcache client.

2. Step 2: Check the LOCATION

   The location is 127.0.0.1:11211, the default Memcached server address on localhost.

3. Final Answer:

   Memcached cache using PyMemcache client on localhost -> Option D

4. Quick Check:

   Memcached backend = PyMemcache + localhost [OK]

Hint: Memcached backend with PyMemcache uses localhost:11211 [OK]

Common Mistakes:

• Confusing Memcached with file or DB cache
• Ignoring the LOCATION setting
• Assuming local memory cache instead

4. Identify the error in this Django cache configuration snippet:

 CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
        'LOCATION': '/tmp/django_cache'
    }
}

medium

A. LocMemCache backend should not have a LOCATION setting

B. The BACKEND string is misspelled

C. LOCATION path must be a database table name

D. The CACHES dictionary must be a list instead

Solution

1. Step 1: Understand LocMemCache usage

   LocMemCache stores cache in local memory and does not use a file path or location setting.

2. Step 2: Identify the incorrect LOCATION key

   Providing a LOCATION with a file path is invalid for LocMemCache and will cause an error.

3. Final Answer:

   LocMemCache backend should not have a LOCATION setting -> Option A

4. Quick Check:

   LocMemCache no LOCATION needed [OK]

Hint: LocMemCache ignores LOCATION, so don't set it [OK]

Common Mistakes:

• Adding LOCATION to LocMemCache
• Confusing file cache with memory cache
• Misunderstanding backend string format

5. You want to configure Django to use a database table named my_cache_table for caching. Which is the correct CACHES setting to achieve this?

hard

A. 'default': {'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache', 'LOCATION': 'my_cache_table'}

B. 'default': {'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache', 'LOCATION': 'my_cache_table'}

C. 'default': {'BACKEND': 'django.core.cache.backends.db.DatabaseCache', 'LOCATION': 'my_cache_table'}

D. 'default': {'BACKEND': 'django.core.cache.backends.locmem.LocMemCache', 'LOCATION': 'my_cache_table'}

Solution

1. Step 1: Identify the backend for database caching

   The backend for caching in a database table is DatabaseCache.

2. Step 2: Set the LOCATION to the table name

   The LOCATION must be the name of the database table, here my_cache_table.

3. Final Answer:

   'default': {'BACKEND': 'django.core.cache.backends.db.DatabaseCache', 'LOCATION': 'my_cache_table'} -> Option C

4. Quick Check:

   DB cache backend + table name = correct config [OK]

Hint: DatabaseCache backend uses table name as LOCATION [OK]

Common Mistakes:

• Using file or memory cache backend for DB caching
• Setting LOCATION to a file path instead of table name
• Confusing Memcached with DB cache