WSO2 WebSocket cannot parse JSON string - json

Question

Since WSO2 5.0 supports WebSockets, I have written a simple app following by tutorials:
WebSocket Transport
Sending a Message from a WebSocket Client to an HTTP Endpoint
Here's my source view output from WSO2:
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://ws.apache.org/ns/synapse">
<registry provider="org.wso2.carbon.mediation.registry.WSO2Registry">
<parameter name="cachableDuration">15000</parameter>
</registry>
<taskManager provider="org.wso2.carbon.mediation.ntask.NTaskTaskManager"/>
<sequence name="fault">
<!-- Log the message at the full log level with the ERROR_MESSAGE and the ERROR_CODE-->
<log level="full">
<property name="MESSAGE" value="Executing default 'fault' sequence"/>
<property expression="get-property('ERROR_CODE')" name="ERROR_CODE"/>
<property expression="get-property('ERROR_MESSAGE')" name="ERROR_MESSAGE"/>
</log>
<!-- Drops the messages by default if there is a fault -->
<drop/>
</sequence>
<sequence name="main">
<in>
<!-- Log all messages passing through -->
<log level="full"/>
<!-- ensure that the default configuration only sends if it is one of samples -->
<!-- Otherwise Synapse would be an open proxy by default (BAD!) -->
<filter regex="http://localhost:9000.*" source="get-property('To')">
<!-- Send the messages where they have been sent (i.e. implicit "To" EPR) -->
<send/>
</filter>
</in>
<out>
<send/>
</out>
<description>The main sequence for the message mediation</description>
</sequence>
<sequence name="outDispatchSeq">
<log level="full">
<property name="MESSAGE" value="Executing outDispatchSeq -------------- "/>
</log>
<respond/>
</sequence>
<sequence name="dispatchSeq">
<payloadFactory media-type="json">
<format>$1</format>
<args>
<arg evaluator="xml" expression="get-property('body')"/>
</args>
</payloadFactory>
<property expression="json-eval($.testPropertyName)"
name="testPropertyName" scope="default" type="STRING"/>
<log level="full">
<property name="MESSAGE" value="Executing dispatchSeq -------------- "/>
</log>
</sequence>
<!-- You can add any flat sequences, endpoints, etc.. to this synapse.xml file if you do
*not* want to keep the artifacts in several files -->
<inboundEndpoint name="test" onError="fault" protocol="ws"
sequence="dispatchSeq" suspend="false">
<parameters>
<parameter name="inbound.ws.port">9091</parameter>
<parameter name="ws.outflow.dispatch.sequence">outDispatchSeq</parameter>
<parameter name="ws.client.side.broadcast.level">0</parameter>
<parameter name="ws.outflow.dispatch.fault.sequence">fault</parameter>
<parameter name="content.type">application/json</parameter>
</parameters>
</inboundEndpoint>
</definitions>
Then I create simple JavaScript code to connect with WebSocket and send simple JSON data:
function connect() {
webSocket = new WebSocket('ws://localhost:9091/');
webSocket.onopen = function(e) {
console.log('connected: ' + webSocket);
};
// some logic here...
webSocket.send("{ \"testPropertyName\": \"testValue\"}");
}
But by all the time, WSO2 cannot parse my JSON object. I am getting errors like:
DEBUG - PayloadFactoryMediator #mediate. Transformed payload format>>>
ERROR - SynapseJsonPath #stringValueOf. Error evaluating JSON Path <$.testPropertyName>. Returning empty result. Error>>> invalid path
INFO - LogMediator To: , MessageID: urn:uuid:93c8c0bc-2a77-4895-a852-1267e21f2044, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Payload: {}
DEBUG - PayloadFactoryMediator #mediate. Transformed payload format>>>
ERROR - SynapseJsonPath #stringValueOf. Error evaluating JSON Path <$.testPropertyName>. Returning empty result. Error>>> invalid path
INFO - LogMediator To: , MessageID: urn:uuid:828216c3-a3ba-476a-886d-302a62e117be, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Payload: {}
UPDATE:
After changing loggin to:
log4j.logger.org.apache.synapse.transport.http.wire=DEBUG
and adding loggig just after payloadFactory:
<sequence name="dispatchSeq">
<payloadFactory media-type="json">
<format>$1</format>
<args>
<arg evaluator="xml" expression="get-property('body')" />
</args>
</payloadFactory>
<log level="full" />
<property expression="json-eval($.testPropertyName)" name="testPropertyName" scope="default" type="STRING" />
<log level="full">
<property name="MESSAGE" value="Executing dispatchSeq -------------- " />
</log>
</sequence>
WSO2 is logging following output:
DEBUG - PayloadFactoryMediator #mediate. Transformed payload format>>>
INFO - LogMediator To: , MessageID: urn:uuid:7a04df37-b3c0-47a0-9ea1-78df460aec0a, Direction: request, Payload: {}
ERROR - SynapseJsonPath #stringValueOf. Error evaluating JSON Path <$.testPropertyName>. Returning empty result. Error>>> invalid path
INFO - LogMediator To: , MessageID: urn:uuid:7a04df37-b3c0-47a0-9ea1-78df460aec0a, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Payload: {}
DEBUG - PayloadFactoryMediator #mediate. Transformed payload format>>>
INFO - LogMediator To: , MessageID: urn:uuid:9ef7732c-b196-435e-a800-5d98d670b11a, Direction: request, Payload: {}
ERROR - SynapseJsonPath #stringValueOf. Error evaluating JSON Path <$.testPropertyName>. Returning empty result. Error>>> invalid path
INFO - LogMediator To: , MessageID: urn:uuid:9ef7732c-b196-435e-a800-5d98d670b11a, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Payload: {}
UPDATE
I removed payloadFactory like:
<sequence name="dispatchSeq">
<log level="full" />
<property expression="json-eval($.testPropertyName)" name="testPropertyName" scope="default" type="STRING" />
<log level="full">
<property name="MESSAGE" value="Executing dispatchSeq -------------- " />
</log>
</sequence>
WSO2 logs show me:
INFO - LogMediator To: , MessageID: urn:uuid:db00d7aa-69c8-4de6-8140-91169183c3d6, Direction: request, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
WARN - SynapseJsonPath Json Payload is empty.
INFO - LogMediator To: , MessageID: urn:uuid:db00d7aa-69c8-4de6-8140-91169183c3d6, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
INFO - LogMediator To: , MessageID: urn:uuid:19816ec6-c255-4edf-adae-cca83dbd2008, Direction: request, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
WARN - SynapseJsonPath Json Payload is empty.
INFO - LogMediator To: , MessageID: urn:uuid:19816ec6-c255-4edf-adae-cca83dbd2008, Direction: request, MESSAGE = Executing dispatchSeq -------------- , Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
UPDATE
Modified dispatchSeq:
<sequence name="dispatchSeq">
<log level="full" />
<property expression="json-eval($.testPropertyName)" name="testPropertyName" scope="default" type="STRING" />
<log level="full">
<property name="MESSAGE" value="Executing dispatchSeq -------------- " />
<property expression="get-property('websocket.source.handshake.present')" name="websocket.source.handshake.present.value" scope="default" type="STRING"/>
</log>
</sequence>
WSO2 output is:
INFO - LogMediator To: , MessageID: urn:uuid:5cc82e8d-6638-4cca-97f7-ac4f96877f85, Direction: request, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
WARN - SynapseJsonPath Json Payload is empty.
INFO - LogMediator To: , MessageID: urn:uuid:5cc82e8d-6638-4cca-97f7-ac4f96877f85, Direction: request, MESSAGE = Executing dispatchSeq -------------- , websocket.source.handshake.present.value = true, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
INFO - LogMediator To: , MessageID: urn:uuid:81b0e2bd-4e79-48bd-b177-f49fd5664c0a, Direction: request, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
WARN - SynapseJsonPath Json Payload is empty.
INFO - LogMediator To: , MessageID: urn:uuid:81b0e2bd-4e79-48bd-b177-f49fd5664c0a, Direction: request, MESSAGE = Executing dispatchSeq -------------- , websocket.source.handshake.present.value = null, Envelope: <?xml version='1.0' encoding='utf-8'?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body/></soapenv:Envelope>
Do you know what else I am missing?
I will appreciate any code examples.
Thank you very much!