Try_files directive in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What happens when try_files finds the first file?

Given this nginx configuration snippet:

location /images/ {
  try_files $uri /default.jpg;
}

What will nginx serve if the requested file /images/logo.png exists on the server?

Nginx

location /images/ {
  try_files $uri /default.jpg;
}

A It serves the file /default.jpg

B It returns a 404 Not Found error

C It serves the file /images/logo.png

D It redirects to /default.jpg

💡 Hint

Try_files checks each file in order and serves the first one that exists.

The try_files directive checks if the requested file exists. If it does, nginx serves it directly without moving to the fallback.

💻 Command Output

intermediate

What is the output when all try_files options fail?

Consider this nginx config:

location /docs/ {
  try_files $uri /index.html =404;
}

If the requested file /docs/manual.pdf does not exist, what will nginx do?

Nginx

location /docs/ {
  try_files $uri /index.html =404;
}

A Redirect to /index.html

B Return a 404 Not Found error

C Serve /docs/manual.pdf anyway

D Serve /index.html

💡 Hint

Try_files tries each option in order until one exists or a fallback is reached.

If $uri does not exist, nginx tries /index.html next. Since /index.html exists, it serves that file.

❓ Troubleshoot

advanced

Why does try_files cause a 404 error unexpectedly?

You have this config:

location /app/ {
  try_files $uri $uri/ /app/index.php?$args;
}

Requests to /app/dashboard return 404 errors even though index.php exists. What is the likely cause?

Nginx

location /app/ {
  try_files $uri $uri/ /app/index.php?$args;
}

A The location block must include 'index index.php;' directive

B The try_files fallback does not trigger internal redirect properly without 'last' or 'break'

C The query string in fallback is ignored, causing 404

D The last parameter should start with an equal sign (=) to avoid 404

💡 Hint

Try_files fallback can cause 404 if internal redirect is not handled correctly.

When try_files falls back to a URI with query string, nginx needs to internally redirect properly. Without 'last' or 'break', it may not process the fallback as expected, causing 404.

✅ Best Practice

advanced

Which try_files usage is best for SPA (Single Page Application)?

You want nginx to serve static files if they exist, but fallback to /index.html for all other routes in a SPA. Which try_files directive is best?

A try_files $uri $uri/ /index.html;

B try_files /index.html $uri $uri/;

C try_files $uri /index.html =404;

D try_files $uri /index.html /404.html;

💡 Hint

Try_files should check static files first, then fallback to index.html for SPA routing.

Option A tries the requested file or directory first, then falls back to /index.html, which is the correct pattern for SPA routing.

🧠 Conceptual

expert

How does try_files interact with alias directive?

Given this config:

location /static/ {
  alias /var/www/assets/;
  try_files $uri /fallback.png;
}

If a client requests /static/logo.png, which file path does try_files check first?

Nginx

location /static/ {
  alias /var/www/assets/;
  try_files $uri /fallback.png;
}

A It checks /var/www/assets/static/logo.png

B It checks /var/www/assets/logo.png

C It checks /static/logo.png on the server root

D It checks /var/www/assets/fallback.png

💡 Hint

Try_files uses the URI, not the alias path, when checking files.

Try_files checks the file path based on the URI. With alias, the URI /static/logo.png maps to /var/www/assets/logo.png, but try_files uses $uri literally, so it checks /var/www/assets/static/logo.png which likely does not exist.