Why is SOAP Causing Such a Lather?

While XML coders have plenty of reasons to be excited about SOAP, to the non-programmer it may seem just another in an endless stream of standards, guidelines, and frameworks of geekish interest only. Indeed, the relationship among SOAP, CORBA, XML schemas, BizTalk et al is rather arcane. But SOAP is a significant step, and the implications are profound for both the technical and the business spheres.

The acceptance of SOAP and its friends shows us that XML has "come of age," or "reached critical mass," to choose two of many possible clichés. It's now apparent that the combination of XML and HTTP will be the tool of choice for enabling applications to communicate with each other over the Internet. Companies that have invested in other, more proprietary ways of doing things will soon find themselves at a disadvantage.

The society debut of SOAP will make it easier to create server- based and/or distributed applications, adding more fuel to the current hosted applications fire. In fact, SOAP could herald a new era of truly distributed computing, in which not just applications, but pieces of the same application, talk to each other over the Internet.

Our concept of what constitutes an application is evolving. A software application used to be thought of as a discrete package of code running on a single computer. Other computers might exchange data with the application over a network, but the app itself sat there in a neat, discrete chunk. Current trends point to a future in which applications run not on a machine, but on entire networks. A three-tier client/server system, in which an application runs on an application server, and data is stored on separate file servers, is one step in this direction. A hosted (or server-based) application takes the concept a step further.

A distributed application can run different parts of the same software program (objects, methods, services, etc.) on different computers, and SOAP provides a theoretical means to do this. There are various possible reasons to do so, from harnessing idle time on some machines to balance the load across a network, to simply creating a super-application by combining the power of many CPUs.

Someone coined the phrase "The network is the computer" a long time ago, but it's only now beginning to come true in a real way. The fewer the barriers to exchanging data among different computing devices, the closer we'll come to the day when the Internet is like one huge computer, the sum of humanity's information processing technology, available anywhere in the Solar System at any time. SOAP and its related technologies are a significant step along the way.

Development Tools for SOAP

Aaron Skonnard has developed a generic SOAP client for IE 5.0. You type in the endpoint and method you want to call, and it whips up the XML for you. It's a handy tool to help you learn the SOAP protocol.
http://www.skonnard.com/soap

Microsoft offers a SOAP Toolkit for Visual Studio® 6.0, which includes "infrastructure necessary to expose SOAP Web Services on Windows operating systems and to consume them." Yum yum! It also includes the Remote Object Proxy Engine (ROPE), a code generation wizard which allows you to make (and presumably consume) SOAP on a ROPE! Just click here if you don't believe me:
http://msdn.microsoft.com/library/periodic/period00/webservice.htm

Further Reading

WDVL's XML Resources

The SOAP 1.1 Spec

xml.com's guide to SOAP

A good in-depth technical description of SOAP, from MSDN

MSDN Search Form – searching for SOAP will generate lots of foam.

Companies Prepare to Clean Up
SOAP, the Simple Object Access Protocol