Data Objects and Variables Available in API Gateway

The following table summarizes the data objects and variables that are available in API Gateway:

The following data objects are available in the request processing or response processing steps:

• ${paramStage.paramType}

  You can use this syntax to access the following string variables: path, statusCode, statusMessage, httpMethod. Examples: ${request.path}, ${response.statusCode}

• ${paramStage.paramType.paramName}

  You can use this syntax to access map types, such as query, headers, and path. Example: ${request.query.var1}, ${response.header.Content-Type}, ${request.path.name}.

• ${paramStage.paramType.queryType[queryValue]}
  You can use this syntax to query a paramType. Examples:

  • ${request.payload.xpath[//ns:emp/ns:empName]}

    Where "//ns:emp/ns:empName" is the XPath to be applied on the payload if contentType is application/xml, text/xml, or text/html.

  • ${response.payload.jsonPath[$.cardDetails.number]}

    Where $.cardDetails.number is the jsonPath to be applied on payload if contentType is application/json or application/json/badgerfish.

  • ${request.payload.regex[[0-9]+]}

    Where [0-9]+ is the regular expression to be applied on the payload if contentType is text/plain.

  Note: While xpath and jsonPath are applicable only to payload, regEx can be used with both payload and path.
• ${paramStage[stepName].paramType.paramName]}

  You can use this syntax to access header or payload from the response of the custom extension in the response processing step.

  Example:

  Variable: ${response.headers.id}

  Value: ${response[customExtension].payload.jsonPath[$.id]}

  This transformation adds a header to the response with name id and its value is derived from the json payload that is sent from the external callout as per the json path.

• You can define your own variables in the Transformation variables field in the response processing step.

  Examples: ${key}, ${value}. The custom transformation variables that you define are available in subsequent steps.