TABLE OF CONTENTS Web Services have had a short but impressive history. In the late 1990s, Microsoft and a couple of other companies were thinking about an XML-based RPC that could work over HTTP. The term SOAP (Simple Object Access Protocol) was coined in 1998. The IETF published the first versions of SOAP 1.0 in December 1999. With broad support from both the commercial and Open Source community, a new version of SOAP emerged. In July 2001, the IETF published the first working draft of SOAP 1.2.
XML, SOAP, WSDL, and UDDI are the core technologies of Web Services While SOAP is certainly at the very core of Web Services, there have been numerous new technologies that extend the scope of application-level interoperability. Just like SOAP, all these technologies are based on XML. Web Services are comprised of the following key technologies:
XML (eXtensible Markup Language) is a general markup language that can be used in a wide variety of contexts. Virtually all Web Service technologies make use of XML in one way or another.
SOAP (Simple Object Access Protocol) defines application-level interoperability. Its purpose resembles that of CORBA's GIOP/IIOP, except that the data representation is based on XML.
WSDL (Web Service Definition Language) allows the specification of service interfaces. Comparing it with CORBA again, it fulfills a similar function as IDL.
UDDI (Universal Description, Discovery and Integration) serves the role of a mediator. Service providers and service requestors use the UDDI registry to...
