QuickStudy: WebDAV

Computerworld - As more and more enterprises use project teams with members based in different locations and time zones—often in different countries or hemispheres—their need for effective electronic collaboration tools has grown dramatically. There are a number of products that aim to solve that problem, and most make at least some use of a single underlying technology.

Web-based Distributed Authoring and Versioning (WebDAV or, more often, just plain DAV) is a standard that extends the capabilities of HTTP 1.1, the underpinning of the World Wide Web.

The protocol has no standard method for moving a file, locking or unlocking it, or adding property information to the file. WebDAV standardizes all of those functions, making the Web writable as well as readable in an interoperable way.

WebDAV was first proposed in 1996, and the current standard, RFC 2518, was published by the Internet Engineering Task Force (IETF) in February 1999. Versioning extensions to WebDAV were codified in RFC 3523 in March 2002.

Diving into DAV

WebDAV extends HTTP by adding new functions, including the following:

• Delete: for deleting a document or other resource.
• PropFind and PropPatch: for reading and writing metadata (also called properties) for a resource.
• MkCol: for creating a new DAV collection (think of folders for organizing files).
• Copy and Move: for copying or moving a resource.
• Lock and UnLock: for protecting editing changes when multiple users access the same document.
• CheckOut and CheckIn: for enabling version control and revision tracking.

HTTP headers aren't long enough to handle some requests, so WebDAV uses XML to format such requests and to store all resource properties. WebDAV version control also makes it possible for users to know which version of a file is the most current.