Open Banking Idempotency Handling Executor

The idempotency handling executor is used to cache the requests. If the same request is repeated within the configured allowed time, the response is returned from the cache without calling the bank back end or the key manager. The extendable idempotency handling executor provided in WSO2 Open Banking Accelerator implements the open banking gateway executor. This uses WSO2 Open Banking Distributed Cache for caching.

According to your requirements, you can extend and override the methods in the OpenBankingIdempotencyHandlingExecutor class to implement the idempotency handling executor according to your open banking requirements.

To achieve the above, extend the following class:

com.wso2.openbanking.accelerator.gateway.executor.idempotency.OpenBankingIdempotencyHandlingExecutor

Given below are the overridable methods used in open banking idempotency handling executor.

• The following table explains the abstract methods that can be overridden:

  Method Name	Parameter	Return Type	Purpose of the Method
  getCreatedTimeFromResponse	OBAPIResponseContext	String	To extract the created time from the response
  getPayloadFromRequest	OBAPIRequestContext	Map<String, Object>	To extract the payload and HTTP status from the request
  isValidIdempotencyRequest	OBAPIRequestContext	boolean	To check if the request is an idempotency valid request
  isValidIdempotencyResponse	OBAPIResponseContext	boolean	To check if the response is an idempotency valid response

• The following table explains the other public/protected methods that can be overridden if needed:

  Method Name	Parameter	Return Type	Purpose of the Method
  handleIdempotencyErrors	OBAPIRequestContext obapiRequestContext, String message, String errorCode	ArrayList<OpenBankingExecutorError>	To handle errors in idempotency validation
  isRequestReceivedWithinAllowedTime	String createdTime	boolean	To check whether the difference between two dates is less than the configured time
  getIdempotencyKeyConstantFromConfig	-	String	To get the Idempotency Key from the configurations

A sample open banking idempotency handling executor implementation is given below:

/**
 * OpenBankingIdempotencyHandlingExecutorImpl.
 */
public class OpenBankingIdempotencyHandlingExecutorImpl extends OpenBankingIdempotencyHandlingExecutor {

    private static final Log log = LogFactory.getLog(OpenBankingIdempotencyHandlingExecutorImpl.class);


    @Override
    public String getCreatedTimeFromResponse(OBAPIResponseContext obapiResponseContext) {
        String createdTime = null;
        if (OBAPIResponseContext.getMsgInfo().getHeaders().get("CreatedTime") != null) {
            //Retrieve response created time from headers
            createdTime = OBAPIResponseContext.getMsgInfo().getHeaders().get("CreatedTime");
        }
        return createdTime;
    }

    @Override
    public Map<String, Object> getPayloadFromRequest(OBAPIRequestContext obapiRequestContext) {
        Map<String, Object> map = new HashMap<>();
        map.put(IdempotencyConstants.PAYLOAD, obapiRequestContext.getRequestPayload());
        map.put(IdempotencyConstants.HTTP_STATUS, HttpStatus.SC_CREATED);
        return map;
    }

    @Override
    public boolean isValidIdempotencyRequest(OBAPIRequestContext obapiRequestContext) {
        return true;
    }

    @Override
    public boolean isValidIdempotencyResponse(OBAPIResponseContext obapiResponseContext) {
        return true;
    }
}

Configuring Open Banking Idempotency Handling Executor¶

1. Configure the open banking distributed cache according to the Distributed Cache documentation.
2. Open the <APIM_HOME>/repository/conf/deployment.toml file.

3. Add the below configurations for open banking idempotency handling executor:

   [open_banking.gateway.cache.idempotency_validation_cache]
   cache_time_to_live=1440
   [open_banking.gateway.idempotency]
   enabled=true
   allowed_time_duration=1440
   idempotency_key_header="x-idempotency-key"

   The following table explains the configurations used in open banking idempotency handling executor:

   Configuration Name	Default Value	Type	Description
   open_banking.gateway.cache.idempotency_validation_cache.cache_time_to_live	1440	integer	Idempotency validation cache time to live in minutes.
   open_banking.gateway.idempotency.enabled	false	boolean	This enables the idempotency handling executor. Idempotency validation works only if this is set to true. Otherwise, the open banking idempotency handling executor will be disabled.
   open_banking.gateway.idempotency.allowed_time_duration	1440	integer	The idempotency available time for the requests. This is checked in the isRequestReceivedWithinAllowedTime method.
   open_banking.gateway.idempotency.idempotency_key_header	x-idempotency-key	string	This configuration takes the header name for the idempotency key.