使用脚本中介调用中介

Question

I'm looking for an API with Call Mediator. Then I want to process the data coming with Script Mediaor and generate output with Respond. If I don't use Script Mediator, my stream will work. But when I want to use Script Mediaor I get the following error.

Unexpected character in preface '{' (code 123); expected '<' in [row,col {unknown source}]: [1,1]

<?xml version="1.0" encoding="UTF-8"?>
<api context="/x" name="x" xmlns="http://ws.apache.org/ns/synapse">
    <resource methods="GET">
        <inSequence>
            <call>
                <endpoint>
                    <http method="get" uri-template="https://jsonplaceholder.typicode.com/users">
                        <suspendOnFailure>
                            <initialDuration>-1</initialDuration>
                            <progressionFactor>-1</progressionFactor>
                            <maximumDuration>0</maximumDuration>
                        </suspendOnFailure>
                        <markForSuspension>
                            <retriesBeforeSuspension>0</retriesBeforeSuspension>
                        </markForSuspension>
                    </http>
                </endpoint>
            </call>
            <script language="js"><![CDATA[var x = mc.getPayloadJSON();

if  (x.id == "1")
mc.setPayloadJSON('{"s":"success"}');
else 
mc.setPayloadJSON('{"s":"error"}');]]></script>
            <respond/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
</api>

Thanks in advance.

Answer 1

The Script Mediator is a content-aware mediator and when you add a content-aware mediator to the mediation flow the message will be built(Binary message converted into a readable format) and brought into the mediation flow. This happens through message builders . From the error snippet you shared, it seems you are receiving a JSON message as a response. So there can be two reasons for this error.

1. As Arunan mentioned, your backend may not be sending the correct Content-Type as a header with the response.
2. The correct message builders are not set in the transport configurations to match the Content-Type header the backend is transmitting.

If you take the second case, first make sure a message builder is set for the default JSON content-type application/json in the <SERVER_HOME>/conf/axis2/axis2.xml . If it's there check if your backend is sending a JSON variation of a default content-type. For example "application/ld+json" etc. If that's the case you need to add a new message builder for this content type. You can refer to this document if you are on MI. If you are on EI refer to this .

Update After checking your comments, it looks like a straightforward integration. Other than the above two reasons this can be the backend altogether sending a wrong response. Are you using the browser to test this API? If so you may be getting a different response due to additional headers added by the browser. Hence please try removing all the transport headers before the call mediator. Refer to the below. Note the <property action="remove" name="TRANSPORT_HEADERS" scope="axis2"/>

<property action="remove" name="TRANSPORT_HEADERS" scope="axis2"/>
<call>
    <endpoint>
        <http method="get" uri-template="https://jsonplaceholder.typicode.com/users">
            <suspendOnFailure>
                <initialDuration>-1</initialDuration>
                <progressionFactor>-1</progressionFactor>
                <maximumDuration>0</maximumDuration>
            </suspendOnFailure>
            <markForSuspension>
                <retriesBeforeSuspension>0</retriesBeforeSuspension>
            </markForSuspension>
        </http>
    </endpoint>
</call>