4.6 Summary

The WebDAV data model enforces consistent addressing, storage, and access for all the information in a repository. A well-defined data model means that clients and servers can be clear about the expected results of various interactions.

WebDAV URLs are HTTP URLs. These URLs include the scheme or protocol name, the server address with optional port, and a relative or path part. The path part of a WebDAV URL is additionally constrained so that the directory hierarchy is reflected in the path, just like file system paths. Directory URLs end in slashes.

Some WebDAV operations act on multiple files. This is done by sending a request to a collection URL and specifying the depth at which the operation will be executed. Depth operations always affect the resource being addressed as well as its child collections and resources.

Resource metadata can be stored as a set of properties with values. Every WebDAV resource has an extensible set of properties. Properties can be numbers, dates, times, or any other data that can be represented as a string. A set of standard properties is required on every resource, including resource type, creation date, and file size.

Locks solve the lost update problem in WebDAV. Any resource can be locked. A collection resource can be locked individually, or all its contained resources can be locked as well (depth infinity). Only the owner of the lock can use the lock token to make changes to a locked resource. Locks can expire so that server resources aren't reserved indefinitely.