Ultra Simple WCF Interface implementation in Biztalk?

Question

I have a series of WCF services that I need to emulate in BizTalk defined using a pattern like this:
  [ServiceContract(Name = "AssignmentService", Namespace = "http://test.org/webservice")]
  public interface IAssignmentNotification
    [OperationContract(Action = "http://test.org/webservice/Assignment")]
    string Assignment(string assignmentXml);
The strings (in and out) are well formed complex xml documents.  The calling system currently is implemented using this type of interface because there were issues getting well-formed NIEM compliant WCF or Soap documents (I'll save that for a different
post later). 
I have searched around, and I do not seem to be able to find any type of example showing how to receive a string, transform it into an Xml-based message (BTW, BizTalk does appear to consume the XML of the message fine to create an XSD that can be used for
mapping); do a bunch of processing, and then turn around and generate an XmlDocument (again, BizTalk can generate an XSD matching the Xml needed here) and finally transforming it into a string.
I have all of the moving parts working, exception for the pipelines to get the strings in/out in a way that conforms to the desired interface.
Does anyone have any pointers or sample code they could share that does this?
Thanks,
John

Answer 1

One of the way out is for you to create a service (pX). This service is what is exposed with your data contract (publish service as WCF).
This service will then get the string (if you use assignmentXml as distinguished) then in the orchestration you'd get receivedMessage.assignmentXml as a string.
You will then have a message type mXtyp (multi-part) in the orchestration where the message type is of the schema you expect to receive, it could be an XmlDocument also.
Now, on receipt of the message, you will utilize a orchestration variable (varXmlDocument of type XmlDocument) to load the entire string as an XmlDocument (use varXmlDocument.LoadXML(receivedMessage.assignmentXml)) and assign it to a Message (mX) of the
type mXtyp as mX.parameters = varXmlDocument [parameters is the name of the body part defined in multi-part message type (mXtyp).
Then you can use Direct Bound ports and publish this. The orchestration which needs to process this message type can similarly use a direct bound port (two-way) to receive and process the message.
The service orchestration (pX) will receive the response and using a similar assignment (reverse) create an XmlDocument and return the XmlDocument.OuterXML as part of its service response.
Regards.
NOTE: you can make pX a generic service where before publishing you can promote messageType on the message and use XmlDocument as the generic published message to direct bound ports. This way you can use the same endpoint to expose multiple service each
of which can consume a specialized XML request/response.