Conditional redirects with if in Nginx - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the if directive do in an nginx configuration?

The if directive checks a condition and executes the code inside its block only if the condition is true. It is often used for conditional redirects or rewrites.

beginner

How do you write a conditional redirect in nginx to send users from http://example.com to https://example.com?

Use the if directive to check if the request is not HTTPS, then use return 301 https://$host$request_uri; to redirect permanently.

intermediate

Why should you avoid complex logic inside nginx if blocks?

Because nginx if is not a full programming language and can cause unexpected behavior or performance issues if used improperly. It's best for simple conditions like redirects.

intermediate

What is the syntax to redirect users to a maintenance page only if the URI contains /old-page?

Use if ($request_uri ~ /old-page) { return 302 /maintenance.html; } inside the server block.

beginner

What HTTP status code is commonly used for permanent redirects in nginx conditional redirects?

The status code 301 is used for permanent redirects, telling browsers and search engines the resource has moved permanently.

Which nginx directive is used to perform conditional redirects?

A location

B map

C if

D proxy_pass

The if directive allows nginx to check conditions and perform actions like redirects.

What does this nginx code do? <br>

if ($scheme = http) { return 301 https://$host$request_uri; }

A Redirects HTTP requests to HTTPS

B Redirects HTTPS requests to HTTP

C Blocks HTTP requests

D Does nothing

It checks if the request uses HTTP and redirects it permanently to the HTTPS version.

Which status code is used for a permanent redirect in nginx?

A 200

B 404

C 500

D 301

Status code 301 means permanent redirect.

What is a risk of using complex logic inside nginx if blocks?

A It can cause unexpected behavior or performance issues

B It can cause nginx to crash

C It will always work perfectly

D It disables logging

Complex logic in if blocks can lead to unexpected results or slow performance.

How do you redirect requests for /old-page to /maintenance.html using nginx if?

A if ($request_uri = /old-page) { return 302 /maintenance.html; }

B if ($request_uri ~ /old-page) { return 302 /maintenance.html; }

C location /old-page { return 404; }

D proxy_pass /maintenance.html;

The ~ operator matches a regex pattern in the URI, triggering the redirect.

Explain how to use the nginx if directive to create a conditional redirect from HTTP to HTTPS.

Think about checking the protocol and redirecting to the secure version.

Describe best practices and limitations when using if for conditional redirects in nginx.

Consider performance and reliability when using <code>if</code>.