Why Nginx handles API routing - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the server listening on port 80.

Nginx

server {
    listen [1];
}

Drag options to blanks, or click blank then click option'

A80

B443

C8080

D22

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 443 without SSL configuration

Using port 22 which is for SSH

The listen directive tells Nginx which port to listen on. Port 80 is the default for HTTP.

2fill in blank

medium

Complete the code to route API requests to the backend server.

Nginx

location /api/ {
    proxy_pass [1];
}

Drag options to blanks, or click blank then click option'

Ahttp://localhost:3000

Bhttps://example.com

Cftp://localhost

Dfile:///var/www

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTPS without backend support

Using file or FTP protocols incorrectly

The proxy_pass directive forwards requests to the backend server. Here, the backend runs on localhost port 3000.

3fill in blank

hard

Fix the error in the proxy header to pass the original host.

Nginx

location /api/ {
    proxy_set_header Host [1];
}

Drag options to blanks, or click blank then click option'

A$remote_addr

Blocalhost

C127.0.0.1

D$host

Attempts:

3 left

💡 Hint

Common Mistakes

Setting Host to localhost breaks backend routing

Using remote address instead of host

Using $host passes the original host header to the backend, which is important for routing and logging.

4fill in blank

hard

Complete the code to rewrite the API URL path correctly.

Nginx

location /api/ {
    proxy_pass http://backend[1]api;
}

Drag options to blanks, or click blank then click option'

A/

C/v1/

D/api/

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the trailing slash causes path concatenation errors

Adding extra /api/ duplicates the path

Adding a trailing slash / after the backend URL and no extra path after api ensures the path is rewritten correctly.

5fill in blank

hard

Fill all three blanks to add caching headers for API responses.

Nginx

location /api/ {
    proxy_pass http://backend/;
    add_header Cache-Control [1];
    add_header Pragma [2];
    add_header Expires [3];
}

Drag options to blanks, or click blank then click option'

A"no-cache"

B"no-store"

C"0"

D"max-age=3600"

Attempts:

3 left

💡 Hint

Common Mistakes

Using max-age enables caching which may cause stale data

Omitting headers leads to default caching behavior

Setting Cache-Control to "no-cache", Pragma to "no-store", and Expires to "0" disables caching for API responses.

Practice

1. Why is Nginx commonly used to handle API routing in web applications?

easy

A. Because it replaces the need for backend servers

B. Because it efficiently directs API requests to the correct backend services

C. Because it stores API data permanently

D. Because it automatically writes API documentation

Solution

1. Step 1: Understand Nginx's role in routing

   Nginx acts as a traffic controller, sending API requests to the right backend service based on rules.

2. Step 2: Identify what Nginx does not do

   Nginx does not store data, replace backend servers, or write documentation; it only routes requests.

3. Final Answer:

   Because it efficiently directs API requests to the correct backend services -> Option B

4. Quick Check:

   Routing = directing requests [OK]

Hint: Nginx routes requests, it doesn't store or create data [OK]

Common Mistakes:

• Thinking Nginx stores API data
• Believing Nginx replaces backend servers
• Assuming Nginx writes API docs

2. Which Nginx directive is used to forward API requests to a backend server?

easy

A. proxy_pass

B. listen

C. server_name

D. root

Solution

1. Step 1: Identify the directive for forwarding requests

   The proxy_pass directive tells Nginx where to send the incoming API requests.

2. Step 2: Differentiate from other directives

   listen sets the port, server_name sets the domain, and root sets the file path, none forward requests.

3. Final Answer:

   proxy_pass -> Option A

4. Quick Check:

   Forwarding = proxy_pass [OK]

Hint: proxy_pass sends requests to backend servers [OK]

Common Mistakes:

• Confusing listen with proxy_pass
• Using root to forward requests
• Mixing server_name with routing

3. Given this Nginx config snippet, what backend URL will a request to /api/users be forwarded to?

location /api/ {
    proxy_pass http://backend-service:8080/;
}

medium

A. http://backend-service:8080/api/users

B. http://backend-service:8080/

C. http://backend-service:8080/api/

D. http://backend-service:8080/users

Solution

1. Step 1: Understand proxy_pass with trailing slash

   Since proxy_pass ends with a slash, Nginx replaces the matching /api/ part in the request URL with the backend URL.

2. Step 2: Apply URL rewrite logic

   Request /api/users becomes /users appended to http://backend-service:8080/, resulting in http://backend-service:8080/users.

3. Final Answer:

   http://backend-service:8080/users -> Option D

4. Quick Check:

   Trailing slash rewrites path [OK]

Hint: Trailing slash in proxy_pass rewrites matched path [OK]

Common Mistakes:

• Appending full original path without rewrite
• Ignoring trailing slash effect
• Assuming no path change

4. Identify the error in this Nginx config that prevents API routing:

location /api {
    proxy_pass http://backend-service:8080;
}

medium

A. Missing trailing slash in location path

B. proxy_pass must use HTTPS instead of HTTP

C. proxy_pass URL missing trailing slash causing path issues

D. location directive should be inside server block

Solution

1. Step 1: Check proxy_pass URL format

   The proxy_pass URL lacks a trailing slash, so Nginx appends the full original request URI, causing incorrect backend paths.

2. Step 2: Understand impact on routing

   Without the trailing slash, requests like /api/users become http://backend-service:8080/api/users which may not be expected by backend.

3. Final Answer:

   proxy_pass URL missing trailing slash causing path issues -> Option C

4. Quick Check:

   Trailing slash in proxy_pass fixes path [OK]

Hint: Always add trailing slash in proxy_pass for correct routing [OK]

Common Mistakes:

• Ignoring trailing slash importance
• Thinking location path needs trailing slash
• Assuming HTTPS is mandatory

5. You want Nginx to route requests starting with /api/v1/ to http://v1-backend:9000/ and requests starting with /api/v2/ to http://v2-backend:9000/. Which configuration correctly achieves this?

hard

A. location /api/v1/ { proxy_pass http://v1-backend:9000/; }\nlocation /api/v2/ { proxy_pass http://v2-backend:9000/; }

B. location /api/ { proxy_pass http://v1-backend:9000/; }\nlocation /api/ { proxy_pass http://v2-backend:9000/; }

C. location /api/v1 { proxy_pass http://v1-backend:9000; }\nlocation /api/v2 { proxy_pass http://v2-backend:9000; }

D. location /api/v1/ { proxy_pass http://v2-backend:9000/; }\nlocation /api/v2/ { proxy_pass http://v1-backend:9000/; }

Solution

1. Step 1: Match location blocks to API versions

   Separate location blocks for /api/v1/ and /api/v2/ ensure requests route to correct backend.

2. Step 2: Use trailing slashes in proxy_pass URLs

   Trailing slashes in proxy_pass ensure correct path rewriting for backend services.

3. Step 3: Verify options

   location /api/v1/ { proxy_pass http://v1-backend:9000/; }\nlocation /api/v2/ { proxy_pass http://v2-backend:9000/; } correctly matches paths and proxies to correct backends. location /api/ { proxy_pass http://v1-backend:9000/; }\nlocation /api/ { proxy_pass http://v2-backend:9000/; } duplicates location blocks, location /api/v1 { proxy_pass http://v1-backend:9000; }\nlocation /api/v2 { proxy_pass http://v2-backend:9000; } misses trailing slashes, location /api/v1/ { proxy_pass http://v2-backend:9000/; }\nlocation /api/v2/ { proxy_pass http://v1-backend:9000/; } swaps backends incorrectly.

4. Final Answer:

   location /api/v1/ { proxy_pass http://v1-backend:9000/; }\nlocation /api/v2/ { proxy_pass http://v2-backend:9000/; } -> Option A

5. Quick Check:

   Separate locations + trailing slash = correct routing [OK]

Hint: Use distinct location blocks with trailing slashes for each API version [OK]

Common Mistakes:

• Using same location for different APIs
• Missing trailing slashes causing path errors
• Swapping backend URLs by mistake