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Web Services Now and When By Clint Boulton November 30, 2004 One of the most significant changes in the software industry has been the arrival of Web services , a truly distributed computing model in which applications "talk" to one another. In short, it's the next evolution of the Web. And for many developers, the future has arrived. In this latest installment of In Focus, in which internetnews.com provides readers with an executive summary of key technology trends, we'll be providing an overview of Web services. "The first phase of the Web was about populating small pieces in the form of individual pages," Joe Kraus, a co-founder of the defunct search portal Excite, stated at the recent Web 2.0 conference. "Phase two is about joining these individual pieces together." Application-to-application communication can enable such tasks as allowing one application to tell another application on a network that a business needs to reload on its inventory. Take a Web services scenario involving widgets. Imagine a business application sitting on a network in a widget distribution supply chain. The app "notices" that inventory is low in London. It could conceivably fire off a query to the applications of other distributors within the supply chain to determine if there are enough widgets to replenish the London warehouse. An application in New York might respond in the affirmative, to which the London-based application might order and automatically pay for — 1,000 widgets. Once the payment has been verified, the New York-based application would then scurry across the network, making sure the order is filled. In this case, the agents on both sides of the service provided and consumed, and fulfilled their jobs thanks to Web services frameworks. That is a classic example of how Web services might work to improve the productivity of the modern business world. It's hard to describe such a transaction without personifying the software performing the operations. That's the whole point, though. Web services could subsume many of the daily responsibilities of humans, freeing them up to perform other tasks. To be fair, picking up the phone to receive an order from a partner around the globe might not seem like a big deal. But take that one example and multiply it by millions to assume the daily glut of business transactions to help explain why Web services are increasing human productivity to an unfathomable degree. Sounds like a technological windfall? To be sure, companies are investing heavily enough in Web services that IDC believes the market will be worth more than $3.2 billion by 2008. The Building Blocks A number of pieces must fall into place before the Web services jigsaw is complete. In order to drive widespread adoption among business customers, high-tech vendors must sell them on the idea that the technology is secure, reliable, manageable, and interoperable, or capable of working with disparate products in the same network. Web services start with a base with distinct technology pillars: XML : This is a specification that comprises the base tagging language for adding more data to Web documents. WSDL : Web Services Description Language. This is an XML-formatted language that describes a Web service's capabilities as collections of communication endpoints capable of exchanging messages. Once they're described, they can be found in a directory using Universal Description, Discovery, and Integration. UDDI Universal Description, Discovery, and Integration. This is where the WSDL is stored. It lists what services are available and how they are stored, managing information about service providers, service implementations, and service metadata. Think of it like the Yellow Pages. SOAP : Simple Object Access Protocol: This is a lightweight XML-based messaging protocol used to encode the information in Web service request and response messages before sending them over a network. It is a kind of envelope that carries information about Web Services messages. Page 2: Building on the Blocks

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