The Calculator Web Service WSDL Document

Summary

WSDL provides a flexible and extensible means of documenting network services. A WSDL document is composed of five elements under the root definitions element: types, message, portType, binding, and service. These elements are used to define Web services through a series of associations.

The types element contains schema definitions for the data exchanged between the client and the server. The default schema language is XML Schema. However, you can specify another schema language through the use of extensibility elements.

The message element identifies a particular message that is exchanged between the client and the server. A message is composed of one or more parts. Each part is represented by the part element and can refer to an element or type definition defined within the types element.

The portTypes element contains one or more operation elements. You can think of an operation as an interface—a contract about how the client and the server will interact with each other to perform an action. An operation can be one of four types: request-response, solicit-response, one-way, or notification.

The binding element is used to associate a port type with a particular protocol. This is accomplished via extensibility elements. Extensibility elements are elements defined outside the WSDL namespace. The WSDL specification defines three sets of extensibility elements for specifying binding information: SOAP, HTTP GET/POST, and MIME. Because specific technologies such as SOAP and HTTP are represented by extensibility elements, WSDL can be used to describe practically any service.

The service element contains one or more port elements. A port element is used to define an address where a Web service that supports a particular binding can be reached.