Parsing Web Interface Description Language WSDL (3)

Web

WSDL documents are divided into two types: service interface and service implementations. (as shown in Figure 3 below)

Figure 3 WSDL Document type

The service interface is described by a WSDL document that contains elements such as types, import, message, PortType, and binding of the service interface. The service interface contains the WSDL service definition that will be used to implement one or more services. It is an abstract definition of a WEB service and is used to describe a particular type of service.

By using an import element, a service interface document can reference another service interface document. For example, a service interface that contains only the message and PortType elements can be referenced by another service interface that contains only the binding of this portType.

The WSDL service implementation document will contain import and service elements. A service implementation document contains a description of the services that implement a service interface. At least one of the import elements will contain a reference to the WSDL service interface document. A service implementation document can contain references to multiple service interface documents.

The import element in the WSDL service implementation document contains two properties. The Namespace property value is a URL that matches the targetnamespace in the Service interface document. The Location property is a URL that refers to a WSDL document that contains the complete service interface definition. The binding property of the port element contains a reference to a specific binding in the Service interface document.

The service interface document is developed and published by the service interface provider. The service implementation document is created and published by the service provider. The service interface provider and the service provider are logically separate roles, but they can be the same business entity.

A complete WSDL service description consists of a service interface and a service implementation document.

4. WSDL Tool

You can create WSDL files by hand, but you can also use a lot of tools to automate the process and definition of Web services for you through WSDL. The recommended tool software is as follows:

Omniopera----The WSDI, XML, and XSD editors of the graphical user interface.
Microsoft's SOAP Toolkit----A toolkit that includes wizards that create COM interfaces based on WSDL definitions, and wizards that create WSDL based on COM interfaces.
IBM's Web Services Toolkit----A toolkit that includes wizards that generate WSDL and SOAP deployment instructions.