WSO2 ESB：聚合来自多个api调用的JSON响应

Question

I am using WSO2 ESB mediators to try and to create an API which paginates a particular Rest API. I am using recursion with the sequence mediator to make calls to a dynamically changing endpoint until all data has been collected. Unfortunately, I cannot figure out how to aggregate all the responses into one JSON before sending.

Any help would be appreciated.

This is the current code:

<api context="/axceleratePaginated" name="axceleratePaginated">
    <resource methods="GET" protocol="http" url-mapping="/courses">
        <inSequence>
            <property name="uri.var.resource" value="courses"/>
            <property name="uri.var.offset" value="0"/>
            <property name="uri.var.displayLength" value="99"/>
            <property name="JSONContinue" value="true"/>
            <sequence key="paginationSequence"/>
            <send/>
        </inSequence>
        <outSequence>
            <!-- aggregate here? -->
            <send/>
        </outSequence>
    </resource>
</api>
...
<sequence name="paginationSequence" trace="enable">
    <header name="apitoken" scope="transport" value="***********"/>
    <header name="wstoken" scope="transport" value="************"/>
    <call>
        <endpoint>
            <http method="GET" trace="enable" uri-template="https://admin.axcelerate.com.au/api/{uri.var.resource}?displayLength={uri.var.displayLength}&amp;offset={uri.var.offset}"/>
        </endpoint>
    </call>
    <property expression="json-eval($.)" name="JSONPayload"/>
    <filter regex="true" source="get-property('JSONContinue')">
        <then>
            <script language="js">
                <![CDATA[
                    java.lang.Thread.sleep(200);
                    var offset = parseInt(mc.getProperty('uri.var.offset'));
                    offset += 100;
                    var pl_string = mc.getProperty('JSONPayload');
                    var JSONPayloadLength = pl_string.length();
                    if (JSONPayloadLength === 3){
                        mc.setProperty('JSONContinue','false');
                    }
                    offset = offset.toString();
                    mc.setProperty('uri.var.offset',offset);
                ]]>
            </script>
            <sequence key="paginationSequence"/>
        </then>
    </filter>
</sequence>

Answer 1

You can use the Loopback mediator [1] to send messages from the in flow (request path) to the out flow (response path).

[1] https://docs.wso2.com/display/ESB490/Loopback+Mediator