E-commerce applications stake out a middle ground

By Kevin Jonah
Special to Government Computer News


Electronic-commerce applications are like Oreo cookies'it's what's in the middle that makes them successful. Middleware tools are what hold the whole endeavor together, making it possible to bridge the Internet and back-end applications without sacrificing security or functionality. Pick the wrong filling, though, and everything falls apart.


Of course, e-commerce middleware doesn't come in just one flavor. There's a choice of software for each type of e-commerce application. Often, you'll need to use multiple tools'or multiple aspects of the same tool'to make your application accessible to everyone who needs it, whether via a Web browser or other access device, from within another application or via document exchange.

With all this complexity, the need for solid data standards is becoming more urgent to ensure projects won't fail.

The key to the success of e-commerce apps'from simple self-service to Internet electronic data interchange'is Extensible Markup Language. Using XML-formatted data and application requests lowers the barriers between Java and Microsoft Windows, Oracle Corp. and IBM Corp. products, and Microsoft Corp. products and everything else.

The most important elements in the emerging XML standards are XML Schema and XML Protocol.

XML Schema is the upcoming replacement for XML document type definitions. With DTDs, developers have to ensure that they apply a DTD that specifically corresponds to the system receiving XML documents, so that data is mapped properly from system to system.

XML Schema provides for a shared data vocabulary among systems, so that rules and data can be dynamically mapped from one system to another without having to exchange DTDs. XML Schema is currently being moved toward adoption as a standard by the World Wide Web Consortium.

Remote procedure calls


XML Protocol, another W3C project, is based on previous attempts to allow remote procedure calls between applications across the Internet using XML, including XML RPC and the Simple Object Access Protocol.

Microsoft and IBM jointly presented SOAP last year to the W3C for consideration as a standard. The W3C committee assigned to evaluate SOAP designated it as a launch point for development of a more fully formed protocol. Several vendors, including Microsoft and IBM, have already implemented SOAP, including an open-source version for Java called SOAP4J, donated by IBM to the Apache Group's open-source Web server.


Meanwhile, another organization, ebXML, is working to standardize XML specifically for worldwide e-commerce. The international consortium, sponsored in part by the United Nations, is working to standardize such things as routing, rule-handling and security in e-commerce implementations of XML. Its goal is that documents generated by different ebXML-compliant software packages can be read by other software, or viewed by people in a common format in a browser.

Though XML Protocol and ebXML are still far from becoming rock-solid standards, XML provides the best way to guarantee interoperability of e-commerce middleware with existing standards. Tools that don't provide a way to integrate XML in some form today will soon be tomorrow's legacy applications'and that's not a legacy you want getting in the way of the success of your e-government initiative.

E-commerce middleware products fall into three layers. First, there's connector middleware, which integrates legacy software with newer Web application software. Connector middleware tools generally are used for translating mainframe application data into a form usable by Web applications. Examples include Information Builders' EDA.

The next class of e-commerce middleware covers application servers, which provide a layer of business logic that handles incoming requests and converts back-end data into an appropriate form for transfer outside a firewall.

This is the broadest class of middleware, including both pre-packaged applications and application development platforms. Outsourced e-commerce solutions such as online marketplaces rely heavily on application server infrastructure.

Some application servers are built with a specific type of e-commerce in mind. Microsoft's BizTalk Server (see story, previous page) is designed for server-to-server connections between organizations, using XML-based messages to perform Internet EDI transactions.

Other application servers rely on custom-built or packaged components to provide business services within their application framework. Many of these servers use the Enterprise JavaBeans component framework for application logic components. Microsoft's Commerce Server 2000 relies on Microsoft's enhanced Component Object Model, known as COM+, while other products offer a blend of the Java and COM worlds.

Messaging layer


The third layer of e-commerce middleware is messaging middleware, which packages and secures data, and guarantees its delivery. These messaging products generally are used to guarantee that transactions are delivered and acted upon in a specific order, and to ensure that more sophisticated applications with complex transaction rules don't fail because of a lack of network bandwidth or a client disconnect.

An e-commerce application may use any or all of these types of middleware, depending on the type of application. A wireless supply requisitioning application, for example, could consist of a wireless application server, multiple types of connector middleware to hook into legacy accounting systems, and messaging middleware'possibly with additional application servers'to handle transaction routing and guarantee secure delivery to an appropriate vendor.

In addition to software tools, Internet commerce has created a growing market for outsourcing most of the middleware problem to online marketplaces and other e-commerce intermediaries. Companies such as Ariba Inc. of Mountain View, Calif., and Commerce One Inc. of Pleasanton, Calif., couple their own connector middleware with a marketplace service. Some enterprise software vendors like SAP America Inc. of Newtown Square, Pa., and PeopleSoft Inc. of Pleasanton, Calif., are making their own e-commerce portal pitches.

With the growing number of marketplace players and the variety of middleware platforms available to build on, making a call about building or buying an e-commerce application solution may be almost as complex as getting that application up and running.

The Lowdown

What is it? E-commerce middleware connects back-end enterprise software and data to users over the Internet or through direct connections via the Web.

What kinds are there? The software comes in three categories: enterprise connector software, application servers and messaging middleware.

When would I need them? If you want to connect legacy applications to application servers, you should consider enterprise connector software. When you need to translate data into many forms for use by many different types of e-commerce applications, you need an application server. When your e-commerce applications integrate from server to server instead of using a Web interface, you will likely need messaging middleware.

Status? Emerging XML standards are bringing the idea of e-commerce closer to reality.

Must-know info? Look for support for XML, including Extensible Stylesheet Language Transformations, Simple Object Access Protocol, a path to supporting XML Schema, and tools for mapping document type definitions from other software. Also, look for support of Internet transport protocols such as Hypertext Transfer Protocol, Secure HTTP and Simple Mail Transfer Protocol.