In the software-as-a-service paradigm of Web services, key factors such as easy service discovery and standards-based deployment will contribute substantially to the ultimate fate of the Web services model’s acceptance. The UDDI (Universal Description, Discovery, and Integration) mechanism currently in place provides a good centralized repository of services from vendors worldwide. But what if you already have a particular suite of services in mind? Why bother parsing international yellow pages of services when you can use a personal address book that comes directly from the vendor?
To this end, IBM Corp. and Microsoft Corp. have announced the WS-Inspection specification to aid the process of Web services discovery. The XML (Extensible Markup Language)-based spec provides a means for service requesters to browse and locate services, as well as retrieve service descriptions and WSDL (Web Services Description Language) documents, directly from a service provider’s Web site without involving a UDDI intermediary.
Before you jump to the conclusion that this is simply another attempt by Microsoft to extend a standard in its favour, realize that WS-Inspection complements, not replaces, UDDI. WS-Inspection employs the same standards already in place for UDDI, while framing an additional means of locating and advertising services that can be used when the provider may already be known.
Services vendors can group together context-relevant service descriptions in a single location, and even augment the location with HTML (HyperText Markup Language)-based marketing content that could help cross-sell complementary services. Although this adds a small degree of maintenance overhead for service providers, they’ll find that the WS-Inspection documents are easily constructed and maintained.
IBM and Microsoft have not yet submitted WS-Inspection to a standards board, but software developers can get their hands on the specification today. To get started, grab the IBM Web Services Toolkit 2.4.1 available at the IBM alphaWorks Web site ( http://www.alphaworks.ibm.com). The free kit includes a run-time environment and samples for jump-starting your development efforts.
Microsoft will include WS-Inspection capabilities in Visual Studio.Net. A sample available on the Microsoft Developer Network Web site ( http://msdn.microsoft.com) includes both a Windows application and an API for developing WSIL (Web Services Inspection Language) documents.
WS-Inspection doesn’t leap over any major hurdles still impeding the acceptance of Web services, but it does represent an advance in rounding out discovery and deployment possibilities that will, in due course, prove beneficial to enterprise Web services consumption.
James R. Borck (firstname.lastname@example.org) is managing analyst in the InfoWorld Test Center.