Intermidiate EDI–Web Services

Web Services

The term Web Services refers to the use of Internet-based standards as a means of sharing information and services between incompatible applications and information sources. By making information and services accessible in a standardized way, Web Services make it easier for businesses to share information inside their organization and with business partners, customers and suppliers. The three main areas of the Web Services Programming Model are:

WSDL (Web Services Definition Language) is used to describe the functions of a Web Service. A WSDL document consists of nine primary XML elements (a.k.a. layers) that describe the functionality of a Web Service and define how to use it. (Source: Gartner, June 2002)

The Definition element is the first element in a WSDL document and specifically provides the namespace and schema information. All other WSDL elements are wrapped up within the Definition element.

Abstract Elements provide general information about what the Web Service does. There are five abstract elements: Port Type, Operation, Message, Part and Type.

Concrete Elements provide information specific to name of an instance of a Web Service, plus the network protocols and address specific to an instance of a Web Service. There are three concrete elements: Service, Port and Binding.

Web Service Publication and Discovery

An organization needs to publish the Web Services that they own so other organizations can discover them. The UDDI (Universal Description, Discovery and Integration) specification is one method used to publish a Web Service to a central UDDI repository. Other organizations can then perform UDDI operations to access the repository and discover Web Services that are of interest to them.

Web Service Invocation

Once an organization has discovered a Web Service via the UDDI interface, they need to invoke the Web Service. This is done via SOAP (Simple Object Access Protocol) over HTTP.

View IPNet's detailed white paper, Web Services and Web Service Agents.