Release 10.1A: OpenEdge Development:
Web Services

Requirements for accessing Web services

For a client application to access a Web service, it must be able to read and write SOAP messages that are transported over HTTP. To accomplish this, you (as the client developer) must first obtain a WSDL file that describes the Web service, then use one of the following techniques to create client code that can access the Web service over the network:

Read the WSDL file to identify the specified Web service operations, then code the client application to directly create, send, and receive the SOAP messages over HTTP required to invoke and handle the responses from these operations. Even with the help of SOAP and HTTP libraries, this requires complex coding for simple operations.
Provide the WSDL file as input to a client development tool that generates a client interface, which shields you from many of the complexities of HTTP and SOAP. A client interface provides the native language API required by the client application to access the Web service. It contains callable units of code written in the client development language that ultimately invoke the operations specified in the WSDL. The code in this interface knows how to create, send, and receive the SOAP over HTTP required to invoke and handle the responses from these operations. Using the client interface, you only need to code the client application to invoke these operations in the development language, with minimal regard for the underlying SOAP management that the interface provides.

In either case, you will also need to consult any user documentation provided by the Web service application developer that explains the programming model for the Web service and how to access its operations.