Web services are gaining industry-wide acceptance and usage. They are moving from proof-of-concept deployments to actual usage in mission-critical enterprise applications. While Web services allow businesses to connect to partners and customers, the same flexibility and connectivity provide an increased opportunity for errors.

COMMENTARY--The rise of internetworking was fueled by the use of network-level security technologies such as SSL, IPSec and firewall filtering to create a secure perimeter around an enterprise network. Today, this secure perimeter has become permeable as enterprises cut costs and drive revenues by securely sharing applications with internal business units, external partners and customers. This shift to the server-to-server access needed for true application sharing is enabled by new XML Web Services technologies.

Flex the power of Web services by learning how to easily leverage them within a Rich Internet Application (RIA) using Macromedia Flex for a more complex, engaging, and interactive client-side experience. RIAs are an evolution of the traditional Web page based model for Web applications. A big part of the attraction in using Flex for RIA development is the speed and ease with which you can leverage Web services in your applications. The authors walk you through several examples and simplify how sometimes confusing WSDL constructs map to Flex declarations.

As Web services standards evolve, those of us involved in their development and adoption are at a crossroads. We strive for open standards, unencumbered by patents and intellectual property rights. We want to compete not in the development of the standards but in how we use them in our products.

Web services protocol workshops allow the whole Web services community to be involved in the process of validating and refining Web services specifications. The workshop process helps to produce well-engineered specifications and prove the interoperability of the Web services specifications with interested parties in the industry. This process has many similarities with the process for software development, and is a deliberate attempt to apply the best practices from the Software Engineering community to the task of producing Web services specifications.

When I started to think about writing this month's column I looked on the Internet for a good way to define service-oriented architecture (SOA). Some of the definitions were interesting, like "A Service Oriented Architecture is basically a Collection of Services" (www.service-architecture.com/). Others were a little bit more technical, such as "SOA is an architectural style whose goal is to achieve loose coupling among interacting software agents" (www.xml.com).

Web services to date have largely been something of a theoretical matter for standards bodies. But real-world development is beginning to proceed in Web services. While not every thread of standards is perfectly in place, teams have moved ahead on this new technology.

“A couple of years ago, we began breaking down application suites into XML-based service methods,” said Steve Flammini, CTO at Partners Healthcare, headquartered in Boston. This began to move the IT infrastructure for the multibillion dollar integrated health care delivery system into the Web services world.

Boston is a walkable city with more than adequate public transportation. It is also a difficult place to keep or even park a car. So it's not surprising that car ownership is not a priority for many of the students at the famous universities -- Harvard, MIT, Boston University and others -- in the Boston area and for older knowledge workers, as well.

Keith Brophy, CTO at Robertson Research Institute, Saginaw, Mich., has been working on a Web services application whose objective has special relevance -- saving lives.

I was recently invited to be a guest speaker at the eBay Developers Conference, where I was part of a panel whose topic was "Delivering the Promise of Web Services." I found it particularly interesting, if slightly worrisome. What struck me most was the differentiation between Web services consumers and Web services authors.

Despite the lack of vendor support, Representational State Transfer (REST) web services have won the hearts of many working developers. For example, Amazon's web services have both SOAP and REST interfaces, and 85% of the usage is on the REST interface. Compared with other styles of web services, REST is easy to implement and has many highly desirable architectural properties: scalability, performance, security, reliability, and extensibility. Those characteristics fit nicely with the modern business environment, which commands technical solutions just as adoptive and agile as the business itself.

BEA Systems Inc., IBM Corp., Microsoft Corp., SAP AG and Sun Microsystems Inc. have submitted the WS-Addressing Web services specification to the Worldwide Web Consortium (W3C) for consideration as a standard, the companies said Tuesday.

When your Web Services move beyond the research stage and you start considering deployment, a production-quality SOAP server becomes a necessity. Just as a Web server provides a platform for deploying Web sites and applications, SOAP servers provide the necessary infrastructure for creating reliable and scalable Web services.

Service-oriented architectures let companies lay the foundation for software that is fast to write, easy to integrate, and runs on a range of platforms.

SQL Server 2000 offers some capabilities for returning XML output via HTTP using SQLXML—and, of course, SQLXML supports Web services creation. Although not rocket science, setting up, configuring, and using Web services in SQL Server 2000 does require a little effort (see the http://www.microsoft.com/sql/techinfo/xml/default.asp SQLXML documentation about Web services in SQL Server 2000).

I want to use web services to build a service-oriented architecture (SOA). What factors should I consider?

The more applications evolve into networks of interacting components and services, the more important it becomes to consider the potential performance issues that typically arise from such distributed architectures. The execution time of certain functions or methods is certainly still important, but the communication time between distributed components now gains influence in terms of its affect on performance considerations. Andre Fachat discusses distributed designs by the means of a shopping cart example. This example is quite simple, but still powerful enough to provide important insights into good and not so good practices. It shows that keeping the communication coarse-grained by reducing the number of remote calls is a good practice. It also proposes an ID-Lists pattern to combine multiple remote calls into one.

Amazon Web Services (AWS) provide two ways to get XML versions of the information that Amazon's customers ordinarily get from HTML web pages: a SOAP interface and a REST interface. It's nice to see the pains that Amazon takes to make it clear that, when it says "web services" it doesn't just mean SOAP-based web services, but REST too. According to Jeff Barr, Amazon's web services evangelist, 80% of the developers using AWS prefer the REST interface.

“A couple of years ago, we began breaking down application suites into XML-based service methods,” said Steve Flammini, CTO at Partners Healthcare, headquartered in Boston. This began to move the IT infrastructure for the multibillion dollar integrated health care delivery system into the Web services world.