Cache-Control headers in Nginx - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Cache-Control header in HTTP?

The Cache-Control header tells browsers and other clients how to store and reuse responses to speed up loading times and reduce server load.

beginner

What does the Cache-Control directive no-cache mean?

It means the client must check with the server before using a cached copy, ensuring the content is fresh.

beginner

How do you set Cache-Control headers in nginx configuration?

Use the add_header Cache-Control "value"; directive inside a server or location block.

beginner

What does the Cache-Control directive max-age=3600 do?

It tells the client to keep the cached response for 3600 seconds (1 hour) before checking for a new version.

intermediate

What is the difference between no-store and no-cache in Cache-Control?

no-store means do not save the response anywhere, while no-cache means save but always revalidate before use.

Which Cache-Control directive tells the browser to store the response but always check with the server before using it?

A public

B no-store

C max-age=3600

D no-cache

The 'no-cache' directive requires the client to revalidate with the server before using the cached response.

How do you add a Cache-Control header in nginx?

A add_header Cache-Control "max-age=3600";

B cache_control max-age=3600;

C set_header Cache-Control max-age=3600;

D cache-control add max-age=3600;

The correct syntax in nginx is 'add_header Cache-Control "value";' inside the server or location block.

What does the Cache-Control directive public mean?

A The response cannot be cached.

B The response can be cached by any cache, even shared ones.

C The response is private to the user.

D The response must be revalidated every time.

'public' means the response can be cached by browsers and shared caches like proxies.

If you want to prevent any caching of a response, which directive should you use?

A no-store

B max-age=0

C public

D must-revalidate

'no-store' prevents the response from being saved in any cache.

What happens if you set max-age=0 in Cache-Control?

A The response is cached forever.

B The response is cached for 0 seconds and then deleted.

C The cached response is considered stale immediately and must be revalidated.

D The response is never cached.

'max-age=0' means the cached response expires immediately and requires revalidation.

Explain how Cache-Control headers affect browser caching behavior and why they are important in nginx configurations.

Think about how browsers decide to reuse or refresh content.

Describe the difference between the Cache-Control directives no-cache and no-store with examples of when to use each.

Focus on whether the response is saved or not.