How to write sample class mediator to get system property and inject to synapse properties / How to generate response with synapse property using script mediator

Here i have added class mediator code and sample synapse configuration to get carbon server home property. To test this create java project and add following class mediator code file to /repository/components/lib directory and add following synapse configuration to source view.  Then you can invoke created proxy service.

Class mediator code.

package main.java.org.wso2.carbon.custommediator;
import org.apache.synapse.MessageContext;
import org.apache.synapse.core.axis2.Axis2MessageContext;
import org.apache.synapse.mediators.AbstractMediator;
public class SampleCustomMediator extends AbstractMediator {

public boolean mediate(MessageContext synapseMsgContext) {
    String carbonHome = System.getProperty("carbon.home");
    log.info("Carbon Home is : "+carbonHome);
    synapseMsgContext.setProperty("CARBON_HOME", carbonHome);
    return true;
 }
 

Synapse configuration.

 

<proxy name="EchoProxyTest"
          transports="https http"
          startOnLoad="true"
          trace="disable">
  <target>
   <inSequence>
     <class name="main.java.org.wso2.carbon.custommediator.SampleCustomMediator"/>
     <sequence key="responseTest"/>
   </inSequence>
   <outSequence>
      <send/>
   </outSequence>
 </target>
</proxy>
<sequence name="responseTest">
      <script language="js">var carbonHome = mc.getProperty("CARBON_HOME");
      var carbonHomeTest = "sanjeewa";
      mc.setPayloadXML(&lt;serverHome&gt;{carbonHome}&lt;/serverHome&gt;);</script>
      <header name="To" action="remove"/>
      <property name="NO_ENTITY_BODY" scope="axis2" action="remove"/>
      <property name="RESPONSE" value="true"/>
      <send/>
      <log level="full"/>
</sequence>

You can invoke create proxy service by calling following URL
https://130.76.202.98:9443/services/EchoProxyTest

Then you will get following response.
 

<serverHome>/home/sanjeewa/work/packs/wso2esb-4.8.0</serverHome>