WebDAV
WebDAV is an Internet Engineering Task Force working group. The abbreviation stands for WWW Distributed Authoring and Versioning.
WebDAV started life when Jim Whitehead convinced the W3C to host two meetings where people interested in the problem of distributed authoring on the World Wide Web could get together to discuss possible solutions. The original vision of the World Wide Web as expounded by Tim Berners-Lee had called for the Web to be both a readable and writable medium and in fact Tim's first web browser, called WorldWideWeb, had been capable of both viewing and editing remote pages. However as the web grew it turned itself into a read only medium. Jim and other like minded people wanted to fix that limitation.
The group of people meeting at the W3C decided that the best way to proceed was to form an IETF working group. The IETF seemed a natural choice as the HTTP protocol was being standardized there and it was assumed that the output of this effort would consist of extensions to that protocol.
As work began on the protocol it became clear that handling both distributed authoring and versioning was just too much and that the task would have to be separated. The WebDAV working group therefore decided to just focus on distributed authoring and leave versioning for the future. In fact members commonly joked that the group should properly be called WebDA.
The WebDAV working group has to date produced several outputs:
- a requirements document: "Requirements for a Distributed Authoring and Versioning Protocol for the World Wide Web" ,
- a base protocol document: "HTTP Extensions for Distributed Authoring -- WEBDAV" ,
- the ordered collections protocol: "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol" and
- the access control protocol: "Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol" .
The protocol consists of a set of new methods and headers for use in HTTP and has the distinction of almost certainly being the first protocol to ever use XML.
WebDAV added the following methods to HTTP:
- PROPFIND - Used to retrieve properties, persisted as XML, from a resource. It is also overloaded to allow one to retrieve the collection structure (a.k.a. directory hierarchy) of a remote system.
- PROPPATCH - Used to change and delete multiple properties on a resource in a single atomic act.
- MKCOL - Used to create collections (a.k.a. directory)
- COPY - Used to copy a resource from one URI to another
- MOVE - Used to move a resource from one URI to another
- LOCK - Used to put a lock on a resource, WebDAV supports both shared and exclusive locks
- UNLOCK - To remove a lock from a resource
A resource is a HTTP specific term which can be roughly defined as 'The thing that is pointed to by a URI'.
The WebDAV working group is still working on a number of extensions to WebDAV including - redirection control, bindings, etc.
The WebDAV working group spawned other IETF working groups including the DAV Searching and Locating (DASL) working group and the Web Versioning and Configuration Management (implementations of WebDAV and WebDAV related standards efforts.
Software supporting WebDAV
See also
