This specification defines an extension to WebDAV that allows
efficient synchronization of the contents of a WebDAV collection.
WebDAV (RFC 4918) defines the concept of 'collections' which are
hierarchical groupings of WebDAV resources on an HTTP
server. Collections can be of arbitrary size and depth (i.e.,
collections within collections). WebDAV clients that cache resource
content need a way to synchronize that data with the server (i.e.,
detect what has changed and update their cache). This can currently
be done using a WebDAV PROPFIND request on a collection to list all
members of a collection along with their DAV:getetag property values,
which allows the client to determine which were changed, added or
deleted. However, this does not scale well to large collections as
the XML response to the PROPFIND request will grow with the
This specification defines a new WebDAV report that results in the
server returning to the client only information about those member
URIs that were added or deleted, or whose mapped resources were
changed, since a previous execution of the report on the collection.
Additionally, a new property is added to collection resources that is
used to convey a "synchronization token" that is guaranteed to change
when the collection's member URIs or their mapped resources have
Working Group Summary
This document is not the product of a working group. However, it
has been discussed on the [hidden email] and reviewed
among implementers in the calendaring and scheduling community.
Consensus was quite smooth. There was some slight controversy
about whether servers should be allowed to return reports with a
depth of infinity, but that issue was decided in the positive because
some implementers have uses for such reporting.
There are several independent implementations (mostly email clients
and calendaring applications).