The World Wide Web Consortium (W3C) this week published Web Services Description Language (WSDL) 1.2, a language based on XML (Extensible Markup Language) that defines the protocol for interactive services on the Web, as well as their data and location.
The W3C also published WSDL 1.2 Bindings, which shows how the specification can be used with Simple Object Access Protocol (SOAP) 1.2, HTTP (Hyptertext Transfer Protocol), and Multipurpose Internet Mail Extensions (MIME).
WSDL and the bindings are the latest in a series of Web services-related drafts out from the W3C. In recent months, the consortium released three drafts directly related to Web services: Web Service Description Usage Scenarios, which outline real-world uses of Web services; and the Web Services Architecture Requirements and Web Service Description Requirements, both of which are designed to clarify the W3C's goals in standardizing Web services.
The W3C last month published an XML Conformance Test Suite, aimed to help developers clean up the Web's XML in advance of a Web services release that will rely on valid XML markup. In February, the W3C called its update on XML Signature a significant tool for securing and authenticating documents exchanged over Web services.
This year's flurry of Web services releases follows a period of relative inaction at the W3C on the Web services front, and subsequent complaints from critics that the W3C was leaving Web services to fracture at the hands of competing providers. The W3C formed its Web Services Activity in January.
The W3C said WSDL 1.2 came with improvements over WSDL 1.1, including clarifications that made its language easier to use and understand, support for the W3C's XML Schemas and XML Information Set recommendations, and a way of conceptually defining description components that is simpler and more flexible than the current method. With Version 1.2, the W3C took out what it called "unnecessary and non-interoperable" technologies and improved the HTTP 1.1 binding.
The W3C also promised a binding for SOAP 1.2 and continued cooperation with the W3C's efforts in what it calls the Semantic Web. Critics have called the Semantic Web--an ambitious undertaking descended from the artificial intelligence world which aims to build a Web of documents that computers can "understand" as well as read--a distraction from the more practical and immediate demands of Web services.
A step ahead in status
Analysts said the new WSDL version made only minor technical progress, but marked a significant step in WSDL's status as a standard.
"It looks like a relatively modest step forward, a set of incremental improvements," said David Schatsky, analyst with Jupiter Research.
"Probably the most significant aspect of it is that it represents the work of the W3C. With this draft of the spec, WSDL formally leaves the control of a small core group of vendors and becomes subject to the W3C process and technical requirements. It's an necessary--and expected--step toward cementing WSDL's status as a key, vendor-neutral standard."
