Gzip compression in Nginx - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Check if gzip is enabled in nginx

You run the command nginx -T | grep gzip to check gzip settings. What output indicates gzip is enabled?

Nginx

nginx -T | grep gzip

A gzip off;

B gzip on;

C # gzip on;

D gzip_disable "msie6";

💡 Hint

Look for the directive that explicitly turns gzip on without being commented out.

The directive gzip on; enables gzip compression in nginx. If it is commented out or set to off, gzip is disabled.

❓ Configuration

intermediate

Configure gzip to compress only text files

Which nginx configuration snippet correctly enables gzip compression only for text-based files?

A

gzip on;
gzip_types text/plain text/css application/javascript;

B

gzip on;
gzip_types application/octet-stream;

C

gzip off;
gzip_types text/plain;

D

gzip on;
gzip_types image/png image/jpeg;

💡 Hint

gzip_types defines which MIME types are compressed. Text files have MIME types like text/plain or text/css.

Option A enables gzip and sets it to compress common text MIME types. Option A tries to compress images which is inefficient. Option A disables gzip. Option A compresses binary streams which is not typical.

❓ Troubleshoot

advanced

Why is gzip not compressing responses?

You enabled gzip in nginx but responses are still not compressed. Which of these is a likely cause?

A The <code>Content-Length</code> header is missing in responses.

B The <code>gzip_min_length</code> is set too low.

C The <code>gzip_disable</code> directive disables gzip for the client browser.

D The server is sending <code>Content-Encoding: gzip</code> header manually.

💡 Hint

Check if gzip is disabled for certain browsers or clients.

The gzip_disable directive disables gzip for specified user agents. If it matches the client, gzip won't compress responses.

✅ Best Practice

advanced

Optimal gzip buffer size configuration

Which buffer size setting is recommended to optimize gzip compression performance in nginx?

A gzip_buffers 4 16k;

B gzip_buffers 1 1k;

C gzip_buffers 16 64k;

D gzip_buffers 2 512k;

💡 Hint

Buffers should be moderate size to balance memory and compression efficiency.

Option A uses 4 buffers of 16k each, which is a common recommended setting balancing memory use and performance. Other options use too small or too large buffers.

🔀 Workflow

expert

Order the steps to enable gzip compression in nginx

Put these steps in the correct order to enable gzip compression on an nginx server.

A 2,1,3,4

B 1,2,4,3

C 1,3,2,4

D 1,2,3,4

💡 Hint

You must edit config before testing and reloading.

First edit the config file, then add gzip directives, test syntax, and finally reload nginx to apply.

Practice

1. What is the main purpose of enabling gzip compression in nginx?

easy

A. To block certain file types from being served

B. To increase the server's CPU usage for better performance

C. To encrypt data between server and client

D. To reduce the size of files sent to the browser, speeding up page load

Solution

1. Step 1: Understand gzip compression purpose

   Gzip compresses files to reduce their size before sending to the browser.

2. Step 2: Connect compression to page load speed

   Smaller files load faster, improving website speed and user experience.

3. Final Answer:

   To reduce the size of files sent to the browser, speeding up page load -> Option D

4. Quick Check:

   gzip compression = smaller files = faster load [OK]

Hint: Remember gzip shrinks files to speed up loading [OK]

Common Mistakes:

• Thinking gzip increases CPU for performance
• Confusing gzip with encryption
• Believing gzip blocks files

2. Which of the following is the correct way to enable gzip compression in nginx configuration?

easy

A. gzip on;

B. gzip enable;

C. enable gzip;

D. gzip true;

Solution

1. Step 1: Recall nginx gzip syntax

   The correct directive to enable gzip is gzip on;.

2. Step 2: Check other options for syntax errors

   Options A, C, and D use invalid keywords or syntax not recognized by nginx.

3. Final Answer:

   gzip on; -> Option A

4. Quick Check:

   Enable gzip with 'gzip on;' [OK]

Hint: Use exact directive 'gzip on;' to enable gzip [OK]

Common Mistakes:

• Using 'gzip enable;' instead of 'gzip on;'
• Writing 'enable gzip;' which is invalid
• Using 'gzip true;' which is not recognized

3. Given this nginx snippet:

gzip on;
gzip_types text/plain application/json;

Which file types will be compressed when served?

medium

A. All file types are compressed

B. Only text/plain and application/json files

C. No files are compressed because gzip_types is incomplete

D. Only binary files are compressed

Solution

1. Step 1: Analyze gzip_types directive

   The directive specifies only text/plain and application/json MIME types for compression.

2. Step 2: Understand gzip on directive effect

   With gzip on;, only the listed types in gzip_types are compressed.

3. Final Answer:

   Only text/plain and application/json files -> Option B

4. Quick Check:

   gzip_types limits compression to listed types [OK]

Hint: gzip_types controls which file types get compressed [OK]

Common Mistakes:

• Assuming all files compress by default
• Thinking gzip_types must list all types including binaries
• Believing gzip_types disables compression

4. You added gzip on; and gzip_types text/html; to nginx.conf but compression is not working. What is the likely mistake?

medium

A. Enabling gzip disables compression by default

B. Using gzip_types with only one type

C. Forgetting to reload nginx after config change

D. Missing gzip_disable directive

Solution

1. Step 1: Check nginx reload requirement

   After config changes, nginx must be reloaded to apply new settings.

2. Step 2: Evaluate other options

   Using one type in gzip_types is valid; gzip on enables compression; gzip_disable disables it for some clients but is optional.

3. Final Answer:

   Forgetting to reload nginx after config change -> Option C

4. Quick Check:

   Reload nginx to apply gzip changes [OK]

Hint: Always reload nginx after config edits [OK]

Common Mistakes:

• Not reloading nginx after config update
• Thinking gzip_types must list many types
• Confusing gzip_disable as required

5. You want to compress HTML, CSS, and JavaScript files in nginx. Which configuration snippet correctly enables gzip for these types?

hard

A. gzip on;\ngzip_types text/html text/css application/javascript;

B. gzip on;\ngzip_types html css js;

C. gzip enable;\ngzip_types text/html text/css application/javascript;

D. gzip on;\ngzip_types text/html text/css js;

Solution

1. Step 1: Verify gzip enabling syntax

   The correct directive to enable gzip is gzip on;, not gzip enable;.

2. Step 2: Check MIME types in gzip_types

   File types must be specified by their MIME types: text/html, text/css, and application/javascript. Using extensions like 'html', 'css', or 'js' is invalid.

3. Final Answer:

   gzip on;\ngzip_types text/html text/css application/javascript; -> Option A

4. Quick Check:

   Use 'gzip on;' and correct MIME types [OK]

Hint: Use MIME types, not file extensions, in gzip_types [OK]

Common Mistakes:

• Using 'gzip enable;' instead of 'gzip on;'
• Listing file extensions instead of MIME types
• Omitting JavaScript MIME type