Map directive for variable mapping in Nginx - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the map directive in nginx?

The map directive creates a new variable whose value depends on the value of another variable. It helps to simplify complex conditional logic by mapping input values to output values.

beginner

How do you define a basic map block in nginx?

You define it with map $input_variable $output_variable { ... } where inside the braces you list input values and their corresponding output values.

intermediate

What happens if no match is found in a map directive?

If no match is found, the map directive uses the value defined by the default keyword if provided, or an empty string otherwise.

intermediate

Can the map directive use regular expressions for matching?

Yes, the map directive supports regular expression matching by prefixing the pattern with ~ for case-sensitive or ~* for case-insensitive matching.

beginner

Where should the map directive be placed in the nginx configuration?

The map directive must be placed in the http context, outside of server or location blocks.

What does the map directive in nginx do?

A Maps one variable's value to another variable's value

B Defines server listening ports

C Sets up SSL certificates

D Configures proxy pass

The map directive creates a new variable based on the value of another variable.

Where must the map directive be placed in nginx config?

A Inside <code>location</code> block

B Inside <code>server</code> block

C Inside <code>events</code> block

D Inside <code>http</code> block

The map directive must be placed in the http context.

How do you specify a default value in a map directive?

A Using the <code>default</code> keyword

B Using <code>else</code> keyword

C Using <code>fallback</code> keyword

D Using <code>catch</code> keyword

The default keyword sets the value if no other match is found.

Which prefix is used for case-insensitive regex matching in map?

A ~

B ~*

C ^~

D *~

The ~* prefix is used for case-insensitive regex matching.

What will be the output variable if no match and no default is set in map?

A Error thrown

B Input variable value

C Empty string

D Null value

If no match and no default, the output variable is an empty string.

Explain how the map directive works in nginx and give an example of its usage.

Think about how you can assign values conditionally without if statements.

Describe where and why you would use the map directive in an nginx configuration.

Consider how nginx handles variables and conditions.