Expires directive in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the effect of this Expires directive in nginx?

Given the nginx configuration snippet:

location /images/ {
  expires 30d;
}

What will be the Cache-Control header value sent to clients for files under /images/?

Nginx

location /images/ {
  expires 30d;
}

A Cache-Control: max-age=3600

B Cache-Control: max-age=2592000

C Cache-Control: no-cache

D Cache-Control: no-store

💡 Hint

30d means 30 days in seconds for max-age.

The 'expires 30d;' directive sets the Cache-Control max-age to 30 days, which is 2592000 seconds.

🧠 Conceptual

intermediate

How does the 'expires' directive affect browser caching?

Which statement best describes the role of the 'expires' directive in nginx?

A It sets how long browsers should cache the resource before requesting it again.

B It disables caching completely for the resource.

C It forces the browser to always revalidate the resource with the server.

D It compresses the resource before sending it to the client.

💡 Hint

Think about cache duration.

The 'expires' directive tells browsers how long to keep a resource cached before fetching it again.

❓ Configuration

advanced

Which nginx configuration sets no caching for CSS files?

You want to configure nginx to prevent caching of CSS files. Which configuration snippet achieves this?

A

location ~* \.css$ {
  expires 1h;
}

B

location ~* \.css$ {
  expires max;
}

C

location ~* \.css$ {
  expires off;
}

D

location ~* \.css$ {
  expires 30d;
}

💡 Hint

'expires off;' disables caching.

'expires off;' disables the Expires header and sets Cache-Control to no-cache, preventing caching.

❓ Troubleshoot

advanced

Why is the Expires header not set as expected?

You configured nginx with:

location /static/ {
  expires 7d;
}

But clients do not receive the Expires header. What is a likely cause?

A The 'expires' directive is inside a location block that is never matched.

B The 'expires' directive requires a reload of the server to take effect.

C The 'expires' directive only works for dynamic content, not static files.

D The 'expires' directive conflicts with gzip compression.

💡 Hint

Check if the location block matches the request path.

If the location block is not matched by the request, the expires directive inside it won't apply.

✅ Best Practice

expert

What is the recommended way to set long cache expiration for versioned static assets?

You have static assets with filenames including version hashes (e.g., app.abc123.js). What is the best practice for setting the 'expires' directive in nginx?

A Do not set 'expires' and rely on browser defaults.

B Set 'expires off;' to disable caching to avoid stale files.

C Set 'expires 1h;' to cache for a short time and reduce stale content risk.

D Set 'expires max;' to cache assets indefinitely since filenames change on updates.

💡 Hint

Versioned filenames allow safe long caching.

Using 'expires max;' allows browsers to cache versioned assets indefinitely, improving performance without stale content risk.