Release 10.1A: OpenEdge Development:
Web Services

Handling communications with Web services

Figure 4–1 shows the HTTP communications model used to exchange SOAP messages between Web service clients and Web services defined with the Web services tools. The HTTP Post method carries a SOAP request message and the HTTP Response carries a SOAP response message. Progress 4GL Web services support this message exchange in accordance with the SOAP 1.1 over HTTP standard.

Figure 4–1: OpenEdge Web services architecture

Note: The WSDL file defines the available Web service methods at development time, while the WSAD file defines the mapping between a Web service method and AppServer procedure at run time. For more information on how these files function in the 4GL Web services development environment, see Chapter 1, " Web Services in OpenEdge."

Each SOAP message is an XML document that consists of the following ordered elements:

SOAP Envelope (mandatory) — Used to define the namespaces used in the document.
SOAP Header (optional) — Used to send the object ID, when required for the object.
SOAP Body (mandatory) — Contains the data and SOAP formatting information. For a SOAP request message, the body contains the method name and its input parameter values. For a SOAP response message, the body contains one of the following sets of components:
Any method output parameters and any return value for a successful request.
A SOAP fault for a failed request.

The remainder of this chapter contains many examples of SOAP messages, with all of these elements.