Regex match (~, ~*) in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Nginx regex match case sensitivity

Given the following nginx location block, what type of requests will it match?

location ~* ".*\.jpg$" { return 200; }

A Requests for URLs ending with .jpg or .JPG (case insensitive)

B Requests for URLs ending with .jpg only (case sensitive)

C Requests for URLs containing .jpg anywhere in the path (case sensitive)

D Requests for URLs ending with .JPG only (case sensitive)

💡 Hint

The ~* operator means case insensitive regex match.

The ~* operator in nginx means a case-insensitive regex match. The pattern ".*\.jpg$" matches any URL ending with .jpg or .JPG or any case variant.

💻 Command Output

intermediate

Nginx regex match case sensitivity difference

What is the difference in matching behavior between these two nginx location blocks?

location ~ ".*\.css$" { return 200; }
location ~* ".*\.css$" { return 200; }

A The first matches only .css exactly in lowercase; the second matches .css in any case

B Both match .css in any case

C The first matches .css in any case; the second matches only lowercase .css

D Both match only lowercase .css

💡 Hint

Check the difference between ~ and ~* operators.

The ~ operator is case sensitive regex match, so it matches only lowercase .css. The ~* operator is case insensitive, so it matches .css, .CSS, .Css, etc.

❓ Troubleshoot

advanced

Why does this nginx regex location not match uppercase extensions?

You have this nginx config:

location ~ ".*\.png$" { return 200; }

You notice requests for image.PNG return 404. Why?

A Because nginx does not support regex in location blocks

B Because the regex is invalid and nginx ignores it

C Because ~ is case sensitive and the regex only matches lowercase .png

D Because the $ anchor is misplaced causing no matches

💡 Hint

Consider the difference between ~ and ~* in nginx.

The ~ operator performs a case sensitive match. So .PNG does not match ".*\.png$". To match uppercase extensions, use ~*.

✅ Best Practice

advanced

Choosing regex match operator for nginx location

Which nginx location regex operator is best to match URLs ending with .html or .HTML regardless of case?

A Use prefix match with ".html"

B Use ~ operator with regex ".*\.html$"

C Use = operator with ".*\.html$"

D Use ~* operator with regex ".*\.html$"

💡 Hint

Think about case sensitivity and regex matching.

The ~* operator performs case-insensitive regex matching, so it matches .html and .HTML. The ~ operator is case sensitive. = is exact match, and prefix match does not support regex.

🧠 Conceptual

expert

Understanding nginx regex match precedence

Given these nginx location blocks:

location /images/ {
  return 404;
}
location ~* ".*\.jpg$" {
  return 200;
}

What happens when a request for /images/photo.JPG is made?

A The prefix location matches first and returns 404 because prefix locations have higher priority

B The regex location matches and returns 200 because regex locations have higher priority

C Nginx returns 404 because regex locations are ignored when prefix matches exist

D Nginx returns 200 because prefix locations are ignored when regex exists

💡 Hint

Nginx chooses regex locations over prefix if regex matches.

Nginx first finds the longest prefix match (/images/), then checks regex locations. If a regex location matches, it takes precedence over prefix. So /images/photo.JPG matches the regex location and returns 200.