Custom Extension Properties

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The table lists the properties that you can specify for a custom extension.

Request Processing Section

The table lists the custom extension properties you can configure in the Request processing section:

Property Description
Payload Provide the request payload to be sent to the custom extension in one of the following ways:
  • Type the request payload in the text box.

    For details on the data objects and variables available in the Request Processing section that you can use to configure, see Data Objects and Variables Available in API Gateway.

  • Click payload format and select one of the following and provide the required information:
    • Inline Request. Type the required payload.
    • Load from Schema. Click Browse to upload a JSON or XML schema file and click Save.
Headers Provide the following information, if you want to configure the headers you need to send to the custom extension. By default, no headers are sent to the custom extension.
  • Select Use incoming headers to use the header content in the incoming requests from the client.
  • Provide the Header Name and the Header Value in the incoming client request that has to be processed.
Query Parameters Provide the following information, if you want to configure query parameters you need to send to the custom extension.
  • Provide the Query Parameter Name and the Query Parameter Value in the incoming client request that has to be processed.

For details on the data objects and variables available in the Request Processing section that you can use to configure, see Data Objects and Variables Available in API Gateway.

Response Processing section

The table lists the custom extension properties you can configure in the Response processing section:

Property Description
Copy the entire response Select to copy the entire response received from the external call out.

This response is used in the subsequent step by using ${request.payload} or ${response.payload}.

Note: Do not select this if you are using AWS Lambda custom extension with invocation type as Event as there is no response returned.
Abort API execution in case of failure Select to abort the API execution when the external callout encounters any failures.

If you do not select this option, API Gateway logs the failure and continues with the processing.

Transformation Specify the following custom variables with a syntax to be accessed from the response of the custom extension and click Add.
  • Variable. Specifies the variable type with a syntax.
  • Value. Specifies a value with a syntax.

For example if you provide a variable as ${var} and the corresponding value as ${response[customExtension].payload.jsonPath[$.id]}, this transformation evaluates the JSON path from the custom policy response payload to get the value of the attribute id. The evaluated value is assigned to the variable var given in the Variable field. You can use the ${var} syntax in the subsequent policies that support variable framework.

For details about the data objects and variables available in the Response Processing section that you can use to configure, see Data Objects and Variables Available in API Gateway.

Custom extension metadata This is used for XML transformation.
  • Namespace Prefix. Provide the namespace prefix of the payload expression to be validated.
  • Namespace URI. Provide the namespace URI of the payload expression to be validated.
Note: By default, the response headers from the custom extension callout are not copied. To include the required headers from the callout, you must copy them using the variable framework.
For example, if you get a response header x-test-header in the callout and wish to copy that header, use the following variable: 
${response[customExtension].headers.x-test-header} to access the value of x-test-header header.

Custom Extension Metadata section

The table lists the custom extension properties you can configure in the Custom Extension Metadata section. This is applicable only for XML transformation.

Property Description
Namespace Prefix Provide the namespace prefix of the payload expression to be validated.
Namespace URI Provide the namespace URI of the payload expression to be validated.

For details about the data objects and variables that you can use to configure, see Data Objects and Variables Available in API Gateway.