Google Contacts and CardDAV

Earlier this week Mark Nottingham wrote about CardDAV and DAV based protocols:

All of this led me to mutter ‘DAV WTF?’ at the IETF APPS Architecture Workshop the other week. Do we really need to give folks the opportunity to mint more application-specific methods and headers?

Interestingly, Lisa Dusseault — one of the core folks in the DAV world — blogged about this the other day;

Were I to propose CalDAV today it would probably be CalAtom — some things would be easier, some harder, but it would catch a wave instead of drifting in the tail of something that was never much of a popular wave. Oh well, we needed something then, and WebDAV gave the most leverage at the time.

I gave a big sigh of relief when I read that, and I hope that the CardDAV folks take this to heart. Some parts of WebDAV (e.g., properties; see Yaron and Larry on this) deserve to be taken out back and shot — although, as Lisa says, they were necessary because of the state of the art at the time. That doesn’t mean we can’t do better now.

Almost as if in answer, yesterday Google announced the release of the Contacts API, which is AtomPub/GData based. Unlike CardDAV, it’s not based on vCard, which is both a blessing and a curse, since lots of popular contact systems (like the Mac address book) know how to export vCard information, and because vCard provides a very rich model for information about people. I’m not sure whether this is progress or not.

3 Responses to “Google Contacts and CardDAV”


  • have to admit i’m not impressed with yet another contact format. but i am intrigued with Atom as a “replacement” for DAV functionality. I had always thought of it as a “push to the client” kind of protocol, not one where the client pushes content back to the server.
    have to dig into that some more…

  • Lets hope that Google adds CardDAV support to Google Contacts when Snow Leopard is released. They did the same with the Calendar, first the GData API and later CalDAV support to connect iCal.app.

    rick: Darwin CalendarServer already supports XMPP PubSub (Jabber) based push for CalDAV, I suppose the same will be done in the upcoming CardDAV server. This will get you “push to the client”.

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