Cache-Control header directives in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the Cache-Control header to prevent caching.

Rest API

response.headers['Cache-Control'] = '[1]'

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

Aprivate

Bmax-age=3600

Cpublic

Dno-cache

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'max-age' which allows caching.

Using 'public' or 'private' which control cache visibility.

The no-cache directive tells browsers not to cache the response.

2fill in blank

medium

Complete the code to set Cache-Control header to cache the response for 1 hour.

Rest API

response.headers['Cache-Control'] = '[1]'

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

Amax-age=3600

Bno-cache

Cno-store

Dmust-revalidate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'no-store' which disables caching.

Using 'no-cache' which requires revalidation.

The max-age=3600 directive tells the browser to cache the response for 3600 seconds (1 hour).

3fill in blank

hard

Fix the error in setting Cache-Control to allow caching only in private caches.

Rest API

response.headers['Cache-Control'] = '[1]'

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

Apublic

Bprivate

Cno-cache

Dno-store

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'public' which allows shared caches.

Using 'no-store' which disables caching.

The private directive allows caching only in private caches like browsers, not shared caches.

4fill in blank

hard

Fill both blanks to set Cache-Control to cache for 30 minutes and require revalidation.

Rest API

response.headers['Cache-Control'] = '[1], [2]'

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

Amax-age=1800

Bno-cache

Cmust-revalidate

Dno-store

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'no-cache' which disables caching.

Using 'no-store' which disables caching completely.

max-age=1800 caches for 1800 seconds (30 minutes), and must-revalidate forces revalidation after expiration.

5fill in blank

hard

Fill all three blanks to set Cache-Control to no-store, no-cache, and private.

Rest API

response.headers['Cache-Control'] = '[1], [2], [3]'

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

Amax-age=0

Bno-store

Cno-cache

Dprivate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'max-age=0' which is less strict than 'no-store'.

Mixing 'public' instead of 'private'.

no-store disables storage, no-cache requires revalidation, and private limits caching to private caches.

Practice

1. What does the Cache-Control: no-store directive instruct browsers to do?

easy

A. Not to save any part of the response in cache

B. Allow caching but revalidate before use

C. Cache the response for a specified time

D. Cache the response only if it is public

Solution

1. Step 1: Understand the meaning of no-store

   The no-store directive means the browser must not save any part of the response in cache.

2. Step 2: Compare with other directives

   Unlike no-cache which allows caching but requires revalidation, no-store forbids storing at all.

3. Final Answer:

   Not to save any part of the response in cache -> Option A

4. Quick Check:

   no-store means no saving [OK]

Hint: No-store means do not save anything at all [OK]

Common Mistakes:

• Confusing no-store with no-cache
• Thinking no-store allows caching with revalidation
• Assuming no-store caches for a short time

2. Which of the following is the correct syntax to set a Cache-Control header that caches content for 3600 seconds?

easy

A. Cache-Control: max-age=3600

B. Cache-Control: maxage:3600

C. Cache-Control: max_age=3600

D. Cache-Control: max-age:3600

Solution

1. Step 1: Recall correct Cache-Control syntax

   The correct syntax uses a hyphen and equals sign: max-age=3600.

2. Step 2: Identify incorrect options

   Options with colon or underscore instead of equals or hyphen are invalid syntax.

3. Final Answer:

   Cache-Control: max-age=3600 -> Option A

4. Quick Check:

   Use hyphen and equals for max-age [OK]

Hint: Use hyphen and equals sign for max-age [OK]

Common Mistakes:

• Using colon instead of equals
• Replacing hyphen with underscore
• Omitting equals sign

3. Given the header Cache-Control: public, max-age=600, what will happen when a browser receives this response?

medium

A. The response will be cached privately for 10 minutes

B. The response will not be cached at all

C. The response will be cached and shared by any user for 10 minutes

D. The response will be cached but must be revalidated every time

Solution

1. Step 1: Understand the public directive

   public means the response can be cached by any cache, including shared caches.

2. Step 2: Interpret max-age=600

   This means the cached response is fresh for 600 seconds (10 minutes) without revalidation.

3. Final Answer:

   The response will be cached and shared by any user for 10 minutes -> Option C

4. Quick Check:

   public + max-age=600 means shared cache for 10 minutes [OK]

Hint: Public means shared cache; max-age sets cache time [OK]

Common Mistakes:

• Thinking public means private caching
• Confusing max-age with no-cache
• Assuming revalidation is always required

4. You see this Cache-Control header in a response: Cache-Control: no-cache, max-age=3600. What is wrong with this header?

medium

A. The syntax is invalid because directives cannot be combined

B. The no-cache directive conflicts with max-age and disables caching

C. There is no error; this header caches for 3600 seconds

D. The max-age value must be zero when no-cache is used

Solution

1. Step 1: Understand no-cache directive

   no-cache means the cache must revalidate before using the cached response.

2. Step 2: Analyze conflict with max-age=3600

   max-age=3600 says the response is fresh for 3600 seconds, but no-cache forces revalidation, effectively disabling caching without validation.

3. Final Answer:

   The no-cache directive conflicts with max-age and disables caching -> Option B

4. Quick Check:

   no-cache overrides max-age freshness [OK]

Hint: No-cache forces revalidation, ignoring max-age freshness [OK]

Common Mistakes:

• Thinking directives cannot be combined
• Assuming max-age always overrides no-cache
• Believing no-cache disables caching completely

5. You want to ensure a sensitive API response is never stored by browsers or intermediate caches. Which Cache-Control header should you use?

hard

A. Cache-Control: no-store, no-cache

B. Cache-Control: private, max-age=0

C. Cache-Control: public, max-age=0

D. Cache-Control: no-store

Solution

1. Step 1: Identify directive that prevents any storage

   no-store tells browsers and caches not to store the response anywhere.

2. Step 2: Compare with other options

   no-cache allows storing but requires revalidation; private allows browser-only caching; public allows shared caching.

3. Final Answer:

   Cache-Control: no-store -> Option D

4. Quick Check:

   no-store forbids all storage [OK]

Hint: Use no-store to block all caching and storage [OK]

Common Mistakes:

• Using no-cache instead of no-store
• Assuming private disables all caching
• Setting max-age=0 without no-store