8 - Web Services

Abstract

Web services are reusable, highly XML-centric, self-contained, self-describing, and self-advertising units of business work—that is, remotely invocable, high-level functions for future e-business applications. The functions include credit-card authorization, international currency-rate converter, stock-quote provider, package delivery-status locator, shipping-rate calculator, local weather update, local traffic update, personalized horoscope, and user authentication. Web services were originally meant to be programmatic—that is, they worked only on a program-to-program basis. As such, they did not come with their own GUI. However, to bring out changes in this scenario, IBM has put forward a proposal for “Web services for remote portals” (WSRP), whereby some Web services can come replete with their own presentation services. This would make Web service integration with portals much easier. The simple object access protocol (SOAP), Web Services Description Language (WSDL), and Universal description, discovery, and integration (UDDI) are enabling technologies for Web services. A web service can be described using WSDL, which is a derivative of EXtensible Markup Language (XML). The WSDL-based descriptions of Web services are published in a UDDI registry so that they can be dynamically located across the Web.