Exposing Systems with SOAP
One of the most intriguing applications of XML in the corporate programming world is the Simple Object Access Protocol. SOAP is essentially an XML-based Remote Procedure Call (RPC) protocol that piggybacks on the existing Hypertext Transfer Protocol (HTTP) supported by every existing Web server.
In operation, a SOAP request consists of an XML message that includes an object, a method, and a set of parameters to invoke on the server URL. The HTTP POST method is used to transmit this information to the SOAP server. The request is then processed by the server, and the results are sent back to the client in XML format as the body of the HTTP response message.
Tightly coupled technologies (such as COM and CORBA) ...