Prefix match in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Nginx prefix match location block behavior

Given the following Nginx configuration snippet, what will be the output when accessing http://example.com/app/test/?

Nginx

server {
    listen 80;
    server_name example.com;

    location /app/ {
        return 200 "Prefix match location";
    }

    location = /app/test {
        return 200 "Exact match location";
    }
}

A Exact match location

B 500 Internal Server Error

C 404 Not Found

D Prefix match location

💡 Hint

Nginx chooses the longest prefix match location block if no exact match is found.

The location /app/ is a prefix match and matches the request URI /app/test/. The location = /app/test is an exact match but it requires the URI to be exactly /app/test without trailing characters. Since the request URI is /app/test/ (with trailing slash), the prefix match location is chosen.

🧠 Conceptual

intermediate

Understanding Nginx prefix match priority

Which statement correctly describes how Nginx selects a prefix match location block when multiple prefix matches exist?

A Nginx selects the prefix location with the shortest matching prefix.

B Nginx selects the prefix location with the longest matching prefix.

C Nginx selects the first prefix location defined in the config file.

D Nginx randomly selects one of the matching prefix locations.

💡 Hint

Think about which prefix is more specific.

Nginx chooses the prefix location with the longest matching prefix to serve the request, as it is the most specific match.

❓ Configuration

advanced

Configuring Nginx prefix match for nested paths

You want Nginx to serve requests to /api/v1/ and all its subpaths with a specific location block. Which configuration snippet correctly uses prefix match to achieve this?

A location /api/v1/ { proxy_pass http://backend; }

B location ^~ /api/v1/ { proxy_pass http://backend; }

C location = /api/v1/ { proxy_pass http://backend; }

D location ~ /api/v1/ { proxy_pass http://backend; }

💡 Hint

Prefix match locations use a simple path without modifiers.

The location /api/v1/ is a prefix match and will match /api/v1/ and all subpaths like /api/v1/users. The = modifier is for exact match, ^~ is for prefix but with higher priority, and ~ is for regex match.

❓ Troubleshoot

advanced

Unexpected location block selection in Nginx

Given this Nginx config, why does a request to /app/test/ get served by the /app/test/ location block instead of /app/?

Nginx

location /app/ {
    return 200 "App prefix";
}

location /app/test/ {
    return 200 "App test prefix";
}

A Because /app/test/ is a longer prefix match than /app/, so it is chosen.

B Because Nginx always prefers the first location block defined.

C Because /app/ is an exact match and /app/test/ is not.

D Because the trailing slash in /app/test/ makes it an exact match.

💡 Hint

Consider prefix length and specificity.

Nginx chooses the location with the longest matching prefix. /app/test/ is longer and more specific than /app/, so it is selected for requests starting with /app/test/.

✅ Best Practice

expert

Optimizing Nginx prefix match with ^~ modifier

Which configuration best ensures that requests starting with /static/ are served directly by Nginx without checking regex locations?

A location ~ /static/ { root /var/www/static; }

B location /static/ { root /var/www/static; }

C location ^~ /static/ { root /var/www/static; }

D location = /static/ { root /var/www/static; }

💡 Hint

The ^~ modifier tells Nginx to stop searching regex locations if this prefix matches.

Using ^~ with a prefix location tells Nginx to use this location immediately if the prefix matches, skipping regex checks. This improves performance for static content.