Web service
A Web service is a service offered by an electronic device to another electronic device, communicating with each other via the World wide web. In a web service, web technology such as the HTTP, originally designed for human-to-machine communication, is utilized for machine-to-machine communication, more specifically for transferring machine readable file formats such as XML and JSON. In practice, the web service typically provides an object-oriented web based interface to a database server, utilized for example by another web server, or by a mobile application, that provides a user interface to the end user. Another common application offered to the end user may be a mashup, where a web server consumes several web services at different machines, and compiles the content into one user interface.
The W3C defines a Web service generally as:
In a 2002 document, the W3C Web Services Architecture Working Group defined a Web Services Architecture, requiring a standardized implementation of a "Web service." In this:
Web Services Flow Language
Web Services Flow Language 1.0 (WSFL) was an XML programming language proposed by IBM in 2001 for describing Web services compositions. Language considered two types of compositions. The first type was to describing business process as a collection of web services and the second was describing interactions in between partners. WSFL was proposed to be layered on top of Web Services Description Language.
In 2003 IBM and Microsoft combined WSFL and Xlang to BPEL4WS and submitted it to OASIS for standardization. Oasis published BPEL4WS as WS-BPEL to properly fit the naming of other WS-* standards.
Web Services Endpoint Language (WSEL)
Web Services Endpoint Language (WSEL) was an XML format proposed to be used to description of non-operational characteristics of service endpoints, such as quality-of-service, cost, or security properties. Format was proposed as a part of report which published Web Service Flow Language . It never gained wide acceptance.
