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Routing a Message to a Dynamic List of Recipients and Aggregating Responses¶

This example demonstrates message routing to a set of dynamic endpoints and aggregate responses.

The sample configuration routes a cloned copy of a message to each recipient defined within the dynamic recipient list, and each recipient responds with a stock quote. When all the responses reach the Micro Integrator, the responses are aggregated to form the final response, which will be sent back to the client.

If you sent the client request through a TCP-based conversation monitoring tool such as TCPMon, you will see the structure of the aggregated response message.

Synapse configuration¶

Following are the integration artifacts you can use to implement this scenario.

Error Handling Sequence

<sequence name="errorHandler">
  <makefault response="true">
     <code xmlns:tns="http://www.w3.org/2003/05/soap-envelope" value="tns:Receiver" />
     <reason value="COULDN'T SEND THE MESSAGE TO THE SERVER." />
  </makefault>
  <send />
</sequence>

Fault Sequence

<sequence name="fault">
  <log level="full">
     <property name="MESSAGE" value="Executing default &quot;fault&quot; sequence" />
     <property name="ERROR_CODE" expression="get-property('ERROR_CODE')" />
     <property name="ERROR_MESSAGE" expression="get-property('ERROR_MESSAGE')" />
  </log>
  <drop />
</sequence>

Proxy Service

<proxy name="RecipientListProxy" startOnLoad="true" transports="http https" xmlns="http://ws.apache.org/ns/synapse">
   <target>
        <inSequence>
            <header name="Action" value="urn:placeOrder"/>
             <property name="EP_LIST" value="http://localhost:9001/services/SimpleStockQuoteService,http://localhost:9002/services/SimpleStockQuoteService,http://localhost:9003/services/SimpleStockQuoteService"/>  
             <send>
                <endpoint>
                   <recipientlist>
                      <endpoints value="{get-property('EP_LIST')}" max-cache="20" />
                   </recipientlist>
                </endpoint>
             </send>
             <drop/>
         </inSequence>
        <outSequence>
            <!--Aggregate responses-->
            <aggregate>
               <onComplete xmlns:m0="http://services.samples"
                              expression="//m0:getQuoteResponse">
                 <log level="full"/>
                 <send/>
               </onComplete>
            </aggregate>
        </outSequence>
        <faultSequence>
            <sequence key="errorHandler"/>
        </faultSequence
    </target>
</proxy>

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