WebDAV, or just DAV, is “Distributed Authoring and Versioning”, a protocol that extends HTTP to allow creating, editing, and managing versions of resources using URLs. DAV completes Tim Berners-Lee’s original vision of the web as not just a collection of read-only resources but of read/write ones.
The main features are:
- The ability to define an access control list (ACL) for a remote web resource, to limit who can write to it.
- The ability to place an exclusive lock (for serial sharing) or a shared lock (for simultaneous sharing) on a remote web resource, just before editing it.
- The ability to get and set properties (metadata) on a remote resource, similar to the filename/creationDate/etc attributes of a file in a file system.
- The ability to define resource collections similar to directories, and references similar to soft links.
Planned extensions to the protocol will define search and versioning should behave.
These features comprise a “network file system”, which on its own is not a new thing. But since this is a protocol, it’s platform-independent. Microsoft, Netscape, and Xerox have all contributed (and Office 2000 supports it), but no corporation dominates its direction.
On a practical note, you might wonder why not just use FTP. Well, that’s not secure. But you could use it with SSH. Yet, not all platforms and apps support SSH; DAV, on the other hand, leverages the security of HTTPS.
IMO, DAV is one of the core Internet technologies of the near future. There is a growing sense that email, documents, webpages/blogs/RSSfeeds, etc have to be tamed through a uniform interface for creating and sharing resources with people. DAV holds the promise of being a uniform underlying technology that could spark that uniform interface. And when such simplifications occur, creativity is freed up to discover new uses.