探索在Wso2 ESB中使用主题和事件

Question

I'm exploring the use of topics and events in WSO2 ESB 4.8.1, I created a topic and subscribed to it the endpoint of one dataservice running in WSO2 WSAS(A), I supposed that if I published a message with the structure defined for the incoming message of one of A operations in the publish tool of the Topic Details console, the message would be sent to the supscriptor (A) and everything where going to work fine, but it don't. Why? I also create a proxy service with an event mediator and configured the event mediator with the name of the created topic. Then I Try the proxy service with an incoming message with the same structure explained before. I was expecting to at least get an incoming message in the WSAS Soap Tracer, but nothing happened. Am I missing something?

Answer 1

The eventing infrastructure is based upon the WS-Eventing specification. Since you are using a WSDL based service as a subscriber of the topic and intend to invoke a specific operation of that service, I imagine it is failing because the SOAP message and/or SOAP action are incorrect because the message sent to the topic and the service are based around WS-Eventing and not your service.

I created the simple proxy below and subscribed it to a topic.

<proxy xmlns="http://ws.apache.org/ns/synapse" name="LogSubMessage" transports="http" statistics="disable" trace="disable" startOnLoad="true">
    <target>
        <inSequence>
            <log level="full" category="ERROR">
                <property name="SERVICE" value="LogSubMessage"/>
            </log>
        </inSequence>
        <outSequence><send/></outSequence>
    </target>
</proxy>

I then sent a <test/> message to the topic.

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Header>
        <ns:topic xmlns:ns="http://wso2.org/ns/2009/09/eventing/notify">topicname</ns:topic>
    </soapenv:Header>
    <soapenv:Body>
        <test/>
    </soapenv:Body>
</soapenv:Envelope>

As you can see in the message above, the message logged in the service contains WS-Eventing SOAP headers and the SOAP action was set to http://ws.apache.org/ws/2007/05/eventing-extended/Publish . If your data service requires that the SOAP header contain the name of the operation to invoke, then it would reject this request.

I would suggest creating a proxy service, similar to the the one above, that would subscribe to the topic. This service would set the correct SOAP action, perform any message transformations you need, and call your data service.