Creating an HL7 Proxy Service

After you install and configure the HL7 transport, you can create a proxy service that uses this transport to connect to an HL7 server. This proxy service will receive HL7-client connections and send them to the HL7 server. It can also receive XML messages over HTTP/HTTPS and transform them into HL7 before sending them to the server, and it will transform the HL7 responses back into XML.

If you want to try the example configurations on this page, you must have an HL7 client and HL7 back-end application set up and running. To see a sample that illustrates how to create an HL7 client and back-end application, see:
http://svn.wso2.org/repos/wso2/carbon/platform/branches/4.1.0/components/business-messaging/hl7/org.wso2.carbon.business.messaging.hl7.samples/4.1.0/.

To create the HL7 proxy service:

In the Management Console, create a custom proxy service (see Adding a Proxy Service).
In the transports list, specify https, http, and hl7.
Create an Address Endpoint with the URL of the HL7 server host and port, such as: hl7://localhost:9988
Add the following parameter to the proxy service (required to enable the transport):
<parameter name="transport.hl7.Port">9292</parameter>

For example:

<proxy xmlns="http://ws.apache.org/ns/synapse" name="hl7testproxy" transports="https,http,hl7" statistics="disable" trace="disable" startOnLoad="true">
       <target>
          <inSequence>
             <log level="full" />
          </inSequence>
          <outSequence>
             <log level="full" />
             <send />
          </outSequence>
          <endpoint name="endpoint_urn_uuid_9CB8D06C91A1E996796270828144799-1418795938">
             <address uri="hl7://localhost:9988" />
          </endpoint>
       </target>
       <parameter name="transport.hl7.Port">9292</parameter>
    </proxy>

For information on additional configuration you can set on the HL7 transport, see HL7 Transport.

Accept acknowledgement

If user doesn't want to wait for the back-end service to process the message and only needs acknowledgment from the system that the message was received, you can configure the proxy service to send an ACK/NACK message after the message is received. For example:

<proxy name="HL7Proxy" transports="hl7" startOnLoad="true" trace="disable">
    <description/>
    <target>
        <inSequence>
            <property name="HL7_RESULT_MODE" value="ACK" scope="axis2"/>
            <property name="HL7_GENERATE_ACK" value="true" scope="axis2"/>
            <send>
               <endpoint name="endpoint_urn_uuid_9CB8D06C91A1E996796270828144799-1418795938">
                    <address uri="hl7://localhost:9988"/>
                </endpoint>
            </send>
        </inSequence>
        <outSequence>
            <log level="custom">
                <property name="OUT" value="***********out sequence proxy2***********"/>
            </log>
           <drop/>
        </outSequence>
     </target>
     <parameter name="transport.hl7.AutoAck">false</parameter>
     <parameter name="transport.hl7.ValidateMessage">false</parameter>
</proxy>

Application acknowledgement

If you want to wait for the application's response before sending the acknowledgment message (see Configuring application acknowledgement), you add the HL7_APPLICATION_ACK property to the inSequence and any additional HL7 properties and transport parameters as needed. For example:

<proxy xmlns="http://ws.apache.org/ns/synapse" name="HL7Proxy" transports="hl7" statistics="disable" trace="disable" startOnLoad="true"> 
  <target> 
      <inSequence> 
           <property name="HL7_APPLICATION_ACK" value="true" scope="axis2"/>  
            <send> 
                  <endpoint name="endpoint_urn_uuid_9CB8D06C91A1E996796270828144799-1418795938"> 
                          <address uri="hl7://localhost:9988"/> 
                   </endpoint> 
             </send> 
      </inSequence> 
      <outSequence>  
           <property name="HL7_RESULT_MODE" value="NACK" scope="axis2"/> 
           <property name="HL7_NACK_MESSAGE" value="error msg" scope="axis2"/> 
           <send/> 
      </outSequence> 
  </target> 
  <parameter name="transport.hl7.AutoAck">false</parameter> 
  <parameter name="transport.hl7.ValidateMessage">true</parameter> 
  <description></description> 
</proxy>

For additional examples of proxy services that handle HL7 messages, see Exchanging HL7 Messages with the File System.