wso2 esb - How to handle request in case of mediator returning false - wso2

Question

I have custom mediator where we are validating internal authentication system. If authentication fails, mediator return false. Client receiving response as HTTP status code 202. This I want to override with some JSON response like { "authError" : "Authetication failed - TOKEN_INVALID" }. Please let me know how to handle such scenarios.
ESB Version - 4.81.
Here is my proxy configuration -
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="UGCGetJSONFileList"
transports="https,http"
statistics="enable"
trace="disable"
startOnLoad="true">
<target outSequence="WEB_OUT_Sequence">
<inSequence>
<log level="full" separator=","/>
<class name="com.hc.synapse.mediator.HCAuthenticationMediator"/>
<property name="RESPONSE" value="true" scope="axis2"/>
<property name="uri.var.querystrings"
expression="substring-after(get-property('To'), '?')"
scope="axis2"
type="STRING"/>
<log level="full" separator=","/>
<switch source="$axis2:HTTP_METHOD">
<case regex="GET">
<property name="uri.var.querystrings"
expression="substring-after(get-property('To'), '?')"
scope="default"
type="STRING"/>
<log level="full" separator=","/>
<send>
<endpoint>
<http method="get"
uri-template="http://dalx-entsvc-d1:9660/ugc/getJSONFileList?{uri.var.querystrings}"/>
</endpoint>
</send>
</case>
<case regex="POST">
<log level="full" separator=","/>
<send>
<endpoint>
<address uri="http://dalx-entsvc-d1:9660/ugc/getJSONFileList?{uri.var.querystrings};content"
trace="enable"
statistics="enable">
<timeout>
<duration>30000</duration>
<responseAction>discard</responseAction>
</timeout>
<suspendOnFailure>
<initialDuration>0</initialDuration>
<progressionFactor>1.0</progressionFactor>
<maximumDuration>0</maximumDuration>
</suspendOnFailure>
</address>
</endpoint>
</send>
</case>
<default/>
</switch>
</inSequence>
<faultSequence>
<log level="full" separator=",">
<property name="trace" expression="get-property('ERROR_MESSAGE')"/>
</log>
<payloadFactory media-type="json">
<format>{ "authError" : "Authetication failed - TOKEN_INVALID" }</format>
<args/>
</payloadFactory>
<property name="RESPONSE" value="true"/>
<header name="To" action="remove"/>
<send/>
</faultSequence>
</target>
<description/>
</proxy>

Answer 1

In your class mediator, you can throw a SynapseException
In this case, inSequence mediation stop and faultSequence will be executed
In the faultSequence, your can use mediator payloadFactory with media-type="json" to build your json message and send it to the client with <send/>