Use BizTalk 2006 as a proxy for an external Web Service

Question

Hi
We have a solution that is going to work just as a proxy for an external Web Service.
It works like this:
1. We have a Request-Response receive port that receives the calls for the WS.
2. Different Static Solicit-Response ports that have filters for each method in the WS receive the requests and then send them to the external WS.
3. The response from the external WS is then sendt back to the caller via the Request-Response port in point 1.
This generally works like it should. The only problem i have is when the external WS returns a Fault message. I get this fault from the external WS:
<s:Fault xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><faultcode>s:Client</faultcode><faultstring xml:lang="nb-NO">Some error message the caller should see.</faultstring><detail><GenericFault
xmlns="http://register.test.com/Common" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><ErrorCode>SomthingWentWrong</ErrorCode><Message>Some error message the caller should see.</Message></GenericFault></detail></s:Fault>
This message then failes on BizTalk and BizTalk returns this Fault message to the caller:
<SOAP:Envelope xmlns:SOAP="http://schemas.xmlsoap.org/soap/envelope/" SOAP:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP:Body><SOAP:Fault><faultcode>Microsoft BizTalk Server Negative Acknowledgment
</faultcode><faultstring>An error occurred while processing the message, refer to the details section for more information </faultstring><faultactor>/Hemit.BizTalk.NHN.Position.ws/IPositionService.asmx</faultactor><detail><ns0:NACK
Type="NACK" xmlns:ns0="http://schema.microsoft.com/BizTalk/2003/NACKMessage.xsd"><NAckID>{7AC314FE-2CA3-44AE-8208-180495500481}</NAckID><ErrorCode>0xc0c016b7</ErrorCode><ErrorCategory>0</ErrorCategory><ErrorDescription>There
is an error in XML document (1, 2).</ErrorDescription><ErrorDetail>&lt;Fault xmlns='http://schemas.xmlsoap.org/soap/envelope/'&gt; was not expected.</ErrorDetail></ns0:NACK></detail></SOAP:Fault></SOAP:Body></SOAP:Envelope>
So the problem seems to be that the Request-Response port in point one will ONLY accept the real response that is specified in the response schema for that particular method, and not a Fault. And when it receives a fault, it generates its own Fault saying
a Fault message was not expected.
Does anyone know how i can be able to send the actual fault from the external WS all the way back to the caller on the inside?
I know how to do it with an orchestration, but can not figure out how to get it done just with the ports.
Kind regars
John Viggo

Answer 1

Hi John,
Enable Propagate fault message
on the WCF solict –response port.
For the two-way send port, you can choose whether to forward
SOAP fault messages on to the original caller over a solicit-response send port by selecting
Propagate fault message. If this option is not selected, BizTalk Server will generate a NACK. What you see is the NACK.
If it is selected, BizTalk Server will treat the message as a valid WCF response message from the external service and the response message will not be suspended because it is propagated.
Then you need to map the fault message to the actual response in the map. Set this Fault-Message to Caller-Response map in the outbound map of the Requeust-Response port.
In this case of messaging-only scenario, this method shall help in handling the fault message and passing fault details back to the caller. Refer the following articles for more details.
Synchronous web services calls and Faults
BizTalk and
SOAPFault
version issues
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