WSDL for Request-Callback Message Exchange
The Request-Callback message exchange is described in WSDL as two separate one-way exchanges.
The WSDL starts with a "Types" section followed by "message definitions". Additionally, it contains two "portType" definitions - one for the request from the consumer to the provider (Library) and one for the response from the provider (LibraryConsumer). The second callback portType contains two operations - one for a regular callback response and one for a callback fault response. Both operations (in LibraryConsumer) declare the Library portType operation as a "partnerOperation" element.
The WSDL used in this message exchange pattern additionally has a "partnerLink" definition, which declares the first portType (Library) as a "service" and the second (LibraryConsumer) as a "callback".
In the following WSDL, the request operation is called seekBookInBasement and that callback operation is called seekBookInBasementResponse:
Example of WSDL with request-callback exchange
<?xml version="1.0" encoding="UTF-8"?>
<definitions
targetNamespace="http://services.talend.org/demos/Library/1.0"
xmlns="http://schemas.xmlsoap.org/wsdl/"
xmlns:err="http://types.talend.org/demos/GeneralObjects/ErrorHandling/1.0"
xmlns:jms="http://schemas.xmlsoap.org/wsdl/jms/"
xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
xmlns:svn="http://types.talend.org/demos/Library/Common/1.0"
xmlns:tns="http://services.talend.org/demos/Library/1.0"
xmlns:tmep="http://types.talend.com/mep/1.0"
xmlns:sdx="http://types.talend.org/service/ServiceDescription/2.0"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<types>
<!-- Refer to the Library example for the complete WSDL -->
......
......
</types>
<message name="seekBookRequest">
<part element="svn:SearchFor" name="body" />
</message>
<message name="seekBookInBasementRequest">
<part element="svn:SearchInBasementFor" name="body" />
</message>
<message name="seekBookResponse">
<part element="svn:ListOfBooks" name="body" />
</message>
<message name="seekBookError">
<part element="err:Exceptions" name="Exception" />
</message>
<portType name="Library">
<operation name="seekBook">
<input message="tns:seekBookRequest" />
<output message="tns:seekBookResponse" />
<fault message="tns:seekBookError" name="error" />
</operation>
<operation name="seekBookInBasement">
<input message="tns:seekBookInBasementRequest" />
</operation>
</portType>
<portType name="LibraryConsumer">
<operation name="seekBookInBasementResponse"
sdx:partnerOperation="seekBookInBasement">
<input message="tns:seekBookResponse" />
</operation>
<operation name="seekBookInBasementFault"
sdx:faultOperation="true" sdx:partnerOperation="seekBookInBasement">
<input message="tns:seekBookError" />
</operation>
</portType>
<plnk:partnerLinkType name="CallbackPartnerLink"
xmlns:plnk="http://schemas.xmlsoap.org/ws/2003/05/partner-link/">
<plnk:role name="service">
<plnk:portType name="tns:Library" />
</plnk:role>
<plnk:role name="callback">
<plnk:portType name="tns:LibraryConsumer" />
</plnk:role>
</plnk:partnerLinkType>
<service name="LibraryProvider">
<port binding="tns:LibraryJmsSoap" name="LibraryJmsPort">
<soap:address
location="jms:jndi:dynamicQueues/library.queue?jndiInitialContextFactory=org.apache.activemq.jndi.ActiveMQInitialContextFactory&jnd
iConnectionFactoryName=ConnectionFactory&jndiURL=tcp://localhost:61616" />
</port>
</service>
<binding name="LibraryJmsSoap" type="tns:Library">
<soap:binding style="document"
transport="http://www.w3.org/2010/soapjms/" />
<operation name="seekBook">
<soap:operation soapAction="seekBook" />
<input>
<soap:body use="literal" />
</input>
<output>
<soap:body use="literal" />
</output>
<fault name="error">
<soap:fault name="error" use="literal" />
</fault>
</operation>
<operation name="seekBookInBasement">
<soap:operation soapAction="seekBookInBasement" />
<input>
<soap:body use="literal" />
</input>
</operation>
</binding>
<service name="LibraryConsumer">
<port binding="tns:LibraryConsumerJmsSoap" name="LibraryConsumerPort">
<soap:address
location="jms:jndi:dynamicQueues/libraryconsumer.queue?jndiInitialContextFactory=org.apache.activemq.jndi.ActiveMQInitialContextFactory&jnd
iConnectionFactoryName=ConnectionFactory&jndiURL=tcp://localhost:61616" />
</port>
</service>
<binding name="LibraryConsumerJmsSoap" type="tns:LibraryConsumer">
<soap:binding style="document"
transport="http://www.w3.org/2010/soapjms/" />
<operation name="seekBookInBasementResponse">
<soap:operation soapAction="seekBookInBasementResponse" />
<input>
<soap:body use="literal" />
</input>
</operation>
<operation name="seekBookInBasementFault">
<soap:operation soapAction="seekBookInBasementFault" />
<input>
<soap:body use="literal" />
</input>
</operation>
</binding>
</definitions>The LibraryConsumer service waits for callback responses from the service provider (listening to the ActiveMQ queue). The operations involved in the message exchange are: seekBookInBasement, seekBookInBasementResponse and seekBookInBasementFault.