Try_files directive in Nginx - Mini Project: Build & Apply

Using the nginx try_files Directive

📖 Scenario: You are setting up a simple nginx web server to serve static files. You want nginx to try to serve a requested file if it exists. If the file does not exist, nginx should serve a default index.html file instead.

🎯 Goal: Configure nginx using the try_files directive to first look for the requested file, and if it is not found, serve index.html as a fallback.

📋 What You'll Learn

Create a basic nginx server block configuration

Add a root directory for static files

Use the try_files directive to check for requested files

Fallback to index.html if the requested file is missing

💡 Why This Matters

🌍 Real World

Web servers often need to serve static files and fallback to a default page for single-page applications or missing files.

💼 Career

Knowing how to configure nginx with try_files is essential for DevOps roles managing web servers and deployments.

1

Create a basic nginx server block

Write a server block with listen 80; and server_name localhost; inside the http context.

Nginx

# Write the server block with listen and server_name
# Your code here

Hint

Start with server { and add listen 80; and server_name localhost; inside.

2

Add the root directory for static files

Inside the existing server block, add a root directive with the value /var/www/html.

Nginx

server {
    listen 80;
    server_name localhost;
    # Add root directive here
    # Your code here
}

Hint

Use root /var/www/html; inside the server block to set the static files directory.

3

Use try_files directive to check requested files

Inside the server block, add a location / block. Inside it, add a try_files directive that tries $uri and $uri/ first, then falls back to /index.html.

Nginx

server {
    listen 80;
    server_name localhost;
    root /var/www/html;

    # Add location block with try_files directive
    # Your code here
}

Hint

Use location / { try_files $uri $uri/ /index.html; } to try requested files and fallback.

4

Print the final nginx configuration

Print the entire nginx configuration you wrote so far.

Nginx

# Print the nginx configuration below
# Your code here

Hint

Print the full nginx configuration text exactly as written.

Practice

1. What is the main purpose of the try_files directive in nginx?

easy

A. To check multiple files or paths in order and serve the first found

B. To restart the nginx server automatically

C. To define user permissions for files

D. To log errors in a custom file

Solution

1. Step 1: Understand the role of try_files

   The try_files directive checks a list of files or paths one by one.

2. Step 2: Identify its purpose

   It serves the first file found or falls back to a default if none exist.

3. Final Answer:

   To check multiple files or paths in order and serve the first found -> Option A

4. Quick Check:

   try_files = check files in order [OK]

Hint: Remember: try_files tries files one by one until success [OK]

Common Mistakes:

• Thinking try_files restarts nginx
• Confusing try_files with permission settings
• Assuming try_files logs errors

2. Which of the following is the correct syntax for the try_files directive in nginx?

easy

A. try_files file1 file2 fallback;

B. try_files file1 file2 =404;

C. try_files file1, file2, fallback;

D. try_files (file1 file2 fallback);

Solution

1. Step 1: Recall try_files syntax rules

   The try_files directive lists files separated by spaces, ending with a fallback like =404.

2. Step 2: Identify correct syntax

   try_files file1 file2 =404; uses spaces and ends with =404, which is valid syntax.

3. Final Answer:

   try_files file1 file2 =404; -> Option B

4. Quick Check:

   try_files syntax uses spaces and fallback [OK]

Hint: Use spaces, no commas or parentheses, end with fallback [OK]

Common Mistakes:

• Using commas between file names
• Adding parentheses around files
• Omitting fallback or using wrong fallback syntax

3. Given this nginx config snippet:

location / {
  try_files $uri $uri/ /index.html;
}

What happens when a user requests /about and /about is not a file but /about/ is a directory?

medium

A. nginx serves the /about file

B. nginx returns a 404 error

C. nginx serves the /about/ directory index

D. nginx serves /index.html fallback

Solution

1. Step 1: Understand try_files order

   nginx first checks if /about file exists, then /about/ directory.

2. Step 2: Apply to given request

   /about file is missing, but /about/ directory exists, so nginx serves the directory index.

3. Final Answer:

   nginx serves the /about/ directory index -> Option C

4. Quick Check:

   try_files checks files then directories [OK]

Hint: try_files checks files then directories in order [OK]

Common Mistakes:

• Assuming it serves /index.html fallback immediately
• Thinking it returns 404 if file missing
• Ignoring directory check after file check

4. Identify the error in this nginx config snippet:

location / {
  try_files $uri, $uri/, /fallback.html;
}

medium

A. Using commas between file names is invalid syntax

B. Missing semicolon at the end of try_files

C. Fallback file must be =404, not /fallback.html

D. Variables like $uri cannot be used in try_files

Solution

1. Step 1: Check try_files syntax

   try_files expects file names separated by spaces, not commas.

2. Step 2: Identify error in snippet

   The commas after $uri and $uri/ cause syntax error.

3. Final Answer:

   Using commas between file names is invalid syntax -> Option A

4. Quick Check:

   try_files uses spaces, no commas [OK]

Hint: No commas in try_files list, only spaces [OK]

Common Mistakes:

• Adding commas between file names
• Confusing fallback with error codes
• Thinking variables are disallowed in try_files

5. You want nginx to try serving /images/$uri, then /images/default.png if the first doesn't exist. Which try_files directive correctly implements this?

hard

A. try_files /images/$uri /images/default.png /index.html;

B. try_files $uri /images/default.png;

C. try_files /images/$uri /images/default.png=404;

D. try_files /images/$uri /images/default.png;

Solution

1. Step 1: Understand file paths in try_files

   To check /images/$uri first, it must be the first argument.

2. Step 2: Choose fallback file

   If the first file is missing, serve /images/default.png as fallback.

3. Step 3: Validate options

   try_files /images/$uri /images/default.png; matches this logic exactly without extra fallbacks or error codes.

4. Final Answer:

   try_files /images/$uri /images/default.png; -> Option D

5. Quick Check:

   try_files lists files in order, fallback last [OK]

Hint: List files in order, fallback last without extra codes [OK]

Common Mistakes:

• Using $uri without /images/ prefix
• Adding unnecessary fallback like =404
• Ending with unrelated fallback like /index.html