Extracts an API key by evaluating an expression on the incoming request. The result (a string) is treated as the API key. The expression is evaluated in the configured language (default: SPEL) during the request flow.

Typical usage inside <apiKey> If the expression evaluates to null or an empty string, no key is extracted.

apiKey:
   extractors:
     - expressionExtractor:
         language: SPEL
         expression: request.headers['X-Api-Key']

apiKey:
   extractors:
     - expressionExtractor:
         language: SPEL
         expression: request.headers['X-Api-Key']

Syntax

expressionExtractor:
  '$ref': <string>
  expression: <string>
  language: groovy
  xmlConfig: {}

expressionExtractor:
  '$ref': <string>
  expression: <string>
  language: groovy
  xmlConfig: {}

Attributes

Name Required Default Description Examples

$ref false - Reference a component defined under components. -

expression

false

The expression evaluated against the message. It must resolve to a String containing the API key. Empty or null results mean “no key found”.

Examples (SPEL):

expression="request.headers['X-Api-Key']"
  expression="request.query['api_key']"

language false - - -

Child Structure

Element	Cardinality	Description
xmlConfig	0..1

Can be used in

apiKey