WSIF and BPEL

Andre P. wrote:
> Hi again Alek!
> Well, I'm using the xsul dynamic invoker to stubless
invoke *any*
> service that I want, in any framework/app server.
> I would like to create a simple scenario with 3
services, and create
> an workflow of this 3 services (first invoke the
service 1 [with
> xsuldyninvoker], then with the return of service 1
invoke service 2
> [with xsuldyninvoker] and then with the return of
service 2 invoke
> service 3 [with xsuldyninvoker too].
yes that should work as it is the simples possible workflow
A -> B -> C
if you use XWSIF (in XSUL) you can access underlying XML
element
(XmlElement) and use XPath processor (Jaxen) to do retrieval
of XML
parts and stuck them into WSIFMessageElement which is
XmlElement
>  
> This solution that you answered is not using BPEL at
all? Just WSIF?
BPEL engine can use WSIF - in such case the engine
orchestrates
invocation of services (main challenge: deal with
concurrency ...)
> In my conception (i'm too lame yet), i was wondering in
something like
> I know my wsdl endpoints previously (at design time of
the BPEL
> workflow), and I "read" the BPEL workflow and
invoke the services with
> the WSIF dyn. invoker (In a BPEL , the invocation is
handled by the
> engine? It can invoke *any* webservice just like the
xsul dynamic
> invoker?)
yes it could however remember that BPEL allow dynamic
assignment of
service reference (so service location can change during
BPEL workflow
execution) - that is clearly for later - after you get
static
invocations to work
>  
> Sorry about my questions, but I'm a little
"new" in this area! 
that is fine - i CC wsif-user so others can add their
comments on
WSIF/BPEL interactions.

best,

alek

>  
>
>     Andre P. wrote:
>>     Hello everyone!
>>     Could anybody please enlighten my ideas!
>>      
>>     I was wondering, how the invocation in the BPEL
is made. Does it
>>     dynamic (stubless) invoke all the (SOAP)
services using their
>>     WSDLs or it's necessary to create all the
proxies for the
>>     services first? How it is done, anybody have
any idea?
>>      
>>     I'm using WSIF (actually WSIF from XSUL library
developed in
>>     Indiana University), and I would like to use it
with BPEL, to
>>     stubless and dynamically invoke all the
(SOAP)services exposed
>>     and involved in my business process workflow!
Is it possible?
>     hi Andre,
>
>     in short: yes.
>
>     steps are pretty simple
>
>        1. you identify which WSDL, operation name and
XML message
>           (content combined by using XML API suchs
xpath, xslt, xquery
>           etc and actual actions described in your
workflow)
>        2. you load wsdl or just get it from cache (so
you have
>           WsdlDefinitions object)
>        3. then using WSIF API you create WSIFPort that
can be used to
>           invoke that operation
>        4. invoke and wait for async response (the
tricky part if you
>           want scalbility you should do it as
request-response as a
>           pair of one-way messages and other tricks to
allow waiting
>           for very long running responses without tying
a thread)
>        5. process response output (agian XML APIs come
handy and it is
>           in your workflow)
>
>     about 3&4: you can use pure WSIF API for
example (with extension
>     that WSIFMessage is XmlElement so you can directly
manipulate it
>     and even access SOAP Header inside - very handy in
workflows  ...)
>     -  see XsulDynamicInvoker for full contained
example
>
>            
WSIFProviderManager.getInstance().addProvider( new
>     xsul.wsif_xsul_soap_http.Provider() );
>
>                 final WSIFServiceFactory
factoryInstance =
>     WSIFServiceFactory.newInstance();
>                 // Do this each time because they might
not be thread
>     safe.
>                 WSIFService service =
>     factoryInstance.getService(this.definitions);
>                 WSIFPort port = service.getPort();
>                 WSIFOperation gFacOperation =
>     port.createOperation(operationName);
>
>                 WSIFMessage inputMessage =
>     gFacOperation.createInputMessage();
>
>             // access XML inside inputMessage and SOAP
Header
>             XmlElement xmlMessage =
((XmlElementAdapter)
>     inputMessage).getTarget();
>             XmlDocument inputEnvelopeDoc =
>     soapFragrance.wrapBodyContent(xmlMessage);
>             if (logger.isFinestEnabled())
logger.finest(" message: "+
>     XsulUtil.safeXmlToString(inputEnvelopeDoc));
>             XmlElement inputEnvelope =
>     inputEnvelopeDoc.getDocumentElement();
>             XmlElement inputHeader =
>     inputEnvelope.element(inputEnvelope
.getNamespace(),
>     XmlConstants.S_HEADER);
>             if (inputHeader == null) {
>                 inputHeader = inputEnvelope.newElement
(
>                         inputEnvelope.getNamespace(),
>     XmlConstants.S_HEADER);
>                 inputEnvelope.insertChild(0,
inputHeader);
>                 inputHeader.setParent(inputEnvelope);
>             }
>             inputHeader.addElement
(leadContextHeaderCopy);
>             // deep magic a.k.a. voodoo deployed here
to connect all
>     living things together ...
>             ((XmlElement)
>     inputMessage).setParent(xmlMessage.getParent());
>      
>
>                 WSIFMessage outputMessage =
>     gFacOperation.createOutputMessage();
>                 WSIFMessage faultMessage =
>     gFacOperation.createFaultMessage();
>
>                
inputMessage.setObjectPart(parameterName, aparamvalue);
>                 // ...
>
>                 boolean success =
>    
gFacOperation.executeRequestResponseOperation(inputMessage,
>     outputMessage, faultMessage);
>                 if (!success) {
>                     // and so on
>
>     or XWSIF extensions that allows client side
handlers, control over
>     asnc responses, timeouts, etc. (see XwsifTestClient
for full
>     contained example)
>
>             WSIFClient wclient =
WSIFRuntime.newClient(wsdlLoc)
>                 .addHandler(new
>    
StickySoapHeaderHandler("use-lead-header",
leadContext))
>                 .useAsyncMessaging(correlator)
>                 //.setAsyncResponseTimeoutInMs(33 *
1000L); // to
>     simplify testing set to just few seconds
>                 .setAsyncResponseTimeoutInMs(0);
//unlimited wait
>
>             WSIFPort port = wclient.getPort();
>             WSIFOperation operation =
port.createOperation("add");
>             WSIFMessage inputMessage =
operation.createInputMessage();
>             WSIFMessage outputMessage =
operation.createOutputMessage();
>             WSIFMessage faultMessage =
operation.createFaultMessage();
>
>             inputMessage.setObjectPart("x",
"2222");
>             inputMessage.setObjectPart("y",
"3333");
>             // and so on like in typical WSIF app
>
>     HTH
>
>     best,
>
>     alek
>


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