45.4.1Camel Processors

Camel processors only require the Camel (CAMEL) module.

45.4.2Channel Import Processor

• Example URI: smile:camel/channelImportProcessor
• Description: Performs similar functionality to the Channel Import Module. Note that this processor assumes that retry and failure processing will be handled by the Camel route. This functionality assumes the JavaScript functions used by ChannelImport are defined in the Camel Module. Note that even though this processor is called channelImportProcessor, it does not interact with a Channel Import Module in any way. It is provided to give users an option to migrate from the Channel Import Module to the Camel Module.
• Input: ResourceOperationJsonMessage
• Output: N/A

45.4.2.1Example Route

The following routes fully replicate the functionality in the Channel Import Module when a ResourceOperationJsonMessage message is posted to the kafka topic called channel-import-in-topic.

<routes xmlns="http://camel.apache.org/schema/spring">
	<route id="channelImportProcessor">
		<from uri="kafka:channel-import-in-topic?brokers=localhost:9092"/>
		<to uri="direct:processMessage"/>
	</route>

	<route id="processResourceOperationMessage">
		<from uri="direct:processMessage"/>
		<onException>
			<exception>ca.uhn.fhir.rest.server.exceptions.ResourceNotFoundException</exception>
			<exception>ca.uhn.fhir.rest.server.exceptions.InvalidRequestException</exception>
			<exception>ca.uhn.fhir.rest.server.exceptions.InternalErrorException</exception>
			<handled>
				<constant>true</constant>
			</handled>
			<to uri="smile:camel/incrementRetryCountProcessor"/>
			<log logName="ca.cdr.camel" message="Error processing ${body}.  Sending to retry queue." loggingLevel="DEBUG"/>
			<to uri="kafka:test.retry?brokers=localhost:9092"/>
		</onException>
		<onException>
			<exception>java.lang.Exception</exception>
			<handled>
				<constant>true</constant>
			</handled>
			<to uri="direct:failureQueue"/>
		</onException>
		<log logName="ca.cdr.camel" message="Processing Resource Operation ${body}" loggingLevel="DEBUG"/>
		<to uri="smile:camel/channelImportProcessor"/>
	</route>

	<route id="retryResourceOperationMessage">
		<from uri="kafka:test.retry?brokers=localhost:9092"/>
		<when>
			<jsonpath>$.headers[?(@.retryCount &lt; 3)]</jsonpath>
			<delay>
				<constant>1000</constant>
			</delay>
			<log logName="ca.cdr.camel" message="Retrying ${body}" loggingLevel="DEBUG"/>
			<to uri="direct:processMessage"/>
		</when>
		<otherwise>
			<to uri="direct:failureQueue"/>
		</otherwise>
	</route>

	<route id="failureQueue">
		<from uri="direct:failureQueue"/>
		<log logName="ca.cdr.camel" message="Error processing ${body}.  Sending to Failure queue." loggingLevel="DEBUG"/>
		<to uri="kafka:test.failed?brokers=localhost:9092"/>
	</route>
</routes>

45.4.3Increment Retry Count Processor

• Example URI: smile:camel/incrementRetryCountProcessor
• Description: This increments the retry count in a BaseJsonMessage (e.g. on a ResourceOperationJsonMessage).
• Input: BaseJsonMessage
• Output: N/A

See the Example Route in channelImportProcessor above for an example of how it can be used.

45.4.3.1Script

• Example URI: smile:camel/script?function=myFunction&input=bundle
• Description: This calls an arbitrary JavaScript function with the input from the route. The optional input parameter will convert the input data before calling the function. If no input parameter is specified, the input will be passed to the function as a String. The following input formats are currently supported:
  • json the input message will be converted into a Json document before calling the function
  • bundle the input message will be converted into a FHIR bundle before calling the function
  • hl7v2 the input message will be converted into an HL7v2 message before calling the function
  • if no input parameter is provided, the input message will be converted into a String before calling the function.
• Input: JSON, IBaseBundle or Hl7v2 Message (depending on configuration)
• Output: N/A

Processor scripts can access the documented JavaScript Execution Environment APIs. However, in cases where a Camel module does NOT have a FHIR Storage module dependency configured, the Fhir API will NOT be available to its processor scripts.

The return value of the function will be passed to the next step in the route.

All functions called by this processor must be defined in the Camel Module.

45.4.3.2Example Routes

Below are example routes using the script processor with each of these input types:

<routes xmlns="http://camel.apache.org/schema/spring">
    <route id="string">
        <from uri="direct:stringStart"/>
        <to uri="smile:camel/script?function=processString"/>
        <to uri="mock:stringResult"/>
    </route>

    <route id="json">
        <from uri="direct:jsonStart"/>
        <to uri="smile:camel/script?function=processJson&amp;input=json"/>
        <to uri="mock:jsonResult"/>
    </route>

    <route id="bundle">
        <from uri="direct:bundleStart"/>
        <to uri="smile:camel/script?function=processBundle&amp;input=bundle"/>
        <to uri="mock:bundleResult"/>
    </route>

    <route id="hl7v2">
        <from uri="direct:hl7v2Start"/>
        <to uri="smile:camel/script?function=processHl7v2&amp;input=hl7v2"/>
        <to uri="mock:hl7v2Result"/>
    </route>
</routes>

Here are some example JavaScript functions that would work with the above routes:

function processString(string) {
   var parts = string.split(/\s+/)

   var patient = ResourceBuilder.build('Patient');
   patient.name[0].given[0] = parts[0];
   patient.name[0].family = parts[1];

   return patient;
}

function processJson(json) {
// Create a patient
   var parts = json.name.split(/\s+/)

   var patient = ResourceBuilder.build('Patient');
   patient.name[0].given[0] = parts[0];
   patient.name[0].family = parts[1];

// Add the patient to a transaction bundle
   var transaction = TransactionBuilder.newTransactionBuilder();
   transaction.create(patient);

   return transaction;
}

function processBundle(bundle) {
   var resources = bundle.entryResources();
   return resources[0].name[0].family;
}

function processHl7v2(message) {
   // Create a patient from an ORU_R01 message
   var patient = ResourceBuilder.build('Patient');
   patient.name[0].family = message['/PATIENT_RESULT[0]/PATIENT/PID-5[0]-1'];
   patient.name[0].given[0] = message['/PATIENT_RESULT[0]/PATIENT/PID-5[0]-2'];

   // Add the patient to a transaction bundle
   var transaction = TransactionBuilder.newTransactionBuilder();
   transaction.create(patient);

   return transaction;
}