A Sacrifice to the Acronym God More than just a simple, handy reference to Web services and its underlying technologies, our Web Services Glossary of terms and technologies is a detangler for all those consortiums, emerging standards, and industry groups that have all of our heads slightly spinning. by Kyle Gabhart and Chris Preimesberger

eb Service (web sur' vis) n. A way to execute remote code and receive the results.

Piece of proverbial cake, right?

Not so fast. Maybe this isn't quite that simple. After all, Web services can mean different things to different people. For some, a Web service is simply a Web application that performs a service. To others, a Web service must involve a monetary transaction. Neither of these definitions fit what is meant by the term "Web service." So, what is a Web service? Here's a shot at a more specific definition:

Web Service (web sur' vis) n. an application that accepts XML-formatted requests from other systems across a network (Internet or intranet) via lightweight, vendor-neutral communications protocols.

Got that? Didn't think so. Okay, let's break this down into more bite-sized pieces.

A Web service is an application that accepts XML-formatted requests...
This means that whether a remote function call is being made on a Web service, or a message is being sent to it, that request must be encapsulated in XML tags.

...from other systems across a network (Internet or Intranet)...
Web services are similar to other distributed computing technologies, enabling remote, distributed, enterprise applications. We'll compare Web services with DCOM, RMI, and CORBA later in this chapter.

...via lightweight, vendor-neutral communications protocols.
The technologies and protocols that Web services rely upon are designed to be relatively lightweight, leaving many of the more complicated features such as security, session-handling, and transaction management to be handled by the underlying transport mechanism. Additionally, these technologies and protocols have been defined within vendor-neutral standards organizations, such as OASIS and the W3C. By using these standardized protocols, any network-enabled, XML-aware application can invoke a Web service, regardless of the programming language or operating system involved.

Index of Terms

Four Key Building Blocks		Other Must-Know Groups, Standards, and Terms
SOAP XML-RPC WSDL UDDI		ebXML.org Digital Signatures JAXP JAXR JAXM JAX-RPC HTTPS Liberty Alliance OASIS Passport PIPs RosettaNet	SAML SunONE UN/CEFACT W3C WebMethod WSFL WS-I XKMS XACML XAML XSLT

The Four Key Building Blocks

In this Article
Introduction	Other Must-Know Groups, Standards, and Terms
The Four Key Building Blocks