Web Services
Note: The Microsoft UDDI SDK is not supported by or included in Microsoft Windows versions after Microsoft Windows Server 7. The Microsoft UDDI V3 SDK is included with Microsoft BizTalk Server. For more information about the Microsoft UDDI V3 SDK, see Microsoft BizTalk Server documentation
Web services represent a progression from a human-oriented use of the Web to an application-centric use of the Web. Web services replace human-driven searches for information with application-driven searches. Applications become the discovering "consumer" as well as the publishing "provider."
Web service applications can perform functions ranging from simple requests to complicated processes, but they all have several common characteristics that distinguish them as a class:
The consumer and provider Web service applications connect over a network. The network can be an intranet (within an organization), an extranet (within an organization including controlled outside partners), or the Internet (within the global community). The connection usually uses the hypertext transport protocol (HTTP) or the secure hypertext transport protocol (HTTPS) to transmit data.
The connection is standardized, but is operating-system and language-independent, so that disparate systems can benefit from Web services. The underlying language that conveys the information is Extensible Markup Language (XML) and this language is phrased using SOAP messaging.
The interfaces of a Web service often are defined using the Web services description language (WSDL), which is a self-describing, common XML grammar. With a definition published in WSDL, a Web service enables other applications to use its services when they have identified and interpreted its definition.
The existence, location, and purpose of a Web service can be published and discovered using Universal Description, Discovery, and Integration (UDDI). UDDI provides a repository for storing Web service descriptions as well as methods for publishing and discovering them.
These Web services, often called XML Web services, emphasize the role of XML as a fundamental messaging language and distinguish them from other types of services available on the Web.