CardDAV Directory
CardDAV Directory is a non-standard extension to the CardDAV protocol, implemented by iOS devices and OS/X Addressbook.
The directory acts as a global read-only addressbook. Both clients don't actually allow you to simply browse them, and will always present just a searching interface.
jsDAV does not provide default backends to create your directories, it provides just a simple interface which you must implement to make this work.
The interface jsCardDAV_iDirectory flags the CardDAV plugin to mark an addressbook
as a directory.
Furthermore, you must also specify the paths to all global CardDAV directories in
the jsCardDAV_Plugin.directories property.
This last step is required, because iOS will request locations to CardDAV directories on the principal, so it must be globally known where these are.
To make sure the directory works everywhere, your node implementing jsCardDAV_iDirectory
must also implement jsDAVACL_iACL.
The OS/X 10.6 client will not request the list of directories, but it rather assumes that there's one located at the /directory path on the root of the server.
So if you want to support this client as well, ensure that that's the exact location of the global addressbook. Because of this, this client will also not be able to support more than 1 directory.
These clients do pick up on the directories property, but they will only support 1 directory at most still.
The CardDAV spec dictates that clients should not do things like a 'Depth: 1' PROPFIND
on the directory. iOS 4 & 5 do this though. When this happens, simply don't return
anything (empty array from getChildren()) rather than throwing an error.
Throwing an error with break iOS 4 and 5.
This appears to be fixed in iOS6.
Based on the original document at http://code.google.com/p/sabredav/wiki/