lower

The lower() function converts the provided string argument to lowercase. This is useful for performing case-insensitive comparisons.

Syntax

lower(value)

Parameters

• value: The string value to convert to lowercase (field name, bytes).

Return Value

Returns the lowercase version of the input string.

Example

lower(http.request.headers["User-Agent"][0]) contains "bot"

Use Cases

• Normalising header values for consistent comparison.
• Implementing case-insensitive matching in rules.
• Standardising input for logging or analysis purposes.