Exact match (=) in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the effect of the exact match (=) in this nginx location block?

Consider this nginx configuration snippet:

location = /about {
    return 200 'Exact match page';
}

What happens when a client requests /about?

Nginx

location = /about {
    return 200 'Exact match page';
}

A The server returns 'Exact match page' for any URI starting with '/about'.

B The server returns 'Exact match page' for any URI containing '/about' anywhere.

C The server returns 'Exact match page' for any URI ending with '/about'.

D The server returns 'Exact match page' only if the request URI is exactly '/about'.

💡 Hint

The '=' sign means the location matches the URI exactly, no more, no less.

The '=' modifier in nginx location means the block matches only if the request URI is exactly the same as the location string. No partial or prefix matches apply.

🧠 Conceptual

intermediate

How does nginx prioritize exact match (=) locations compared to prefix matches?

Given these location blocks:

location = /test {
    return 200 'Exact';
}
location /test {
    return 200 'Prefix';
}

Which location block will nginx use for a request to /test?

Nginx

location = /test {
    return 200 'Exact';
}
location /test {
    return 200 'Prefix';
}

A nginx uses the exact match location (= /test) before the prefix match (/test).

B nginx uses the prefix match (/test) before the exact match (= /test).

C nginx merges both locations and returns both responses.

D nginx returns a 404 error because of conflicting locations.

💡 Hint

Exact match locations have the highest priority in nginx.

nginx first checks for exact match locations (=). If found, it uses that block. Only if no exact match is found does it check prefix matches.

❓ Troubleshoot

advanced

Why does this nginx config not serve the exact match location as expected?

You have this config:

location = /home {
    proxy_pass http://backend1;
}
location /home {
    proxy_pass http://backend2;
}

Requests to /home are always served by backend2. Why?

Nginx

location = /home {
    proxy_pass http://backend1;
}
location /home {
    proxy_pass http://backend2;
}

A The request URI includes a trailing slash, so it does not exactly match '/home'.

B The exact match location is ignored because proxy_pass is missing a trailing slash.

C nginx does not support exact match locations with proxy_pass directives.

D The exact match location is overridden by the prefix location because of order in the config file.

💡 Hint

Check if the request URI exactly matches the location string, including trailing slashes.

If the client requests '/home/' (with trailing slash), it does not exactly match '= /home'. So nginx uses the prefix location '/home' instead.

✅ Best Practice

advanced

What is the recommended use of exact match (=) locations in nginx?

Which of these is the best practice when using exact match (=) locations in nginx?

A Avoid exact match locations because they cause nginx to reload the config on every request.

B Use exact match locations for specific URIs that need unique handling, like redirects or special responses.

C Use exact match locations for all static files to improve performance.

D Use exact match locations to match all URIs starting with a prefix.

💡 Hint

Exact match locations are precise and should be used sparingly for special cases.

Exact match locations are best for handling specific URIs that require unique behavior, such as redirects or custom responses. They are not for general prefix matching.

🔀 Workflow

expert

Order the steps nginx follows to select a location block for a request URI

Arrange the steps nginx uses to find the correct location block for a request URI, considering exact match (=), prefix, and regex locations.

A 1,3,2,4

B 2,1,3,4

C 1,2,3,4

D 3,1,2,4

💡 Hint

Exact matches have highest priority, then prefix, then regex.

nginx first checks exact match locations (=). If none, it finds the longest prefix match. Then it tests regex locations in order. If a regex matches, it uses that; otherwise, it uses the prefix match.