Google announced yesterday a new service for syncing Gmail contacts and up to five Google calendars with mobile devices, even  the iPhone by offering M$ ActiveSync for compatible devices.

As expected set-up is quick and easy, even directly from the iPhone, and it works even though the beta state rather. As long as your contacts do not have more than one mobile number. But there is at least one new problem to solve: how to get Apple Adressbook sync again with Gmail?

Since Mac OSX 10.5.3 there is a new feature that enables Apple Address Book sync with Gmail by using the Google Data APIs Objective-C Client Library - not only for iPhone and iPod touch owners. It works very well, although not all fields are synced correctly. Maybe this is the niche commercial solutions like Spanning Sync.

However to re-enable the “Sync Now” function, i found a two command solution at Google mobile help. By default, the sync client for Google is an “app client”, which means it requires some other address book to run (MobileMe, Yahoo, Exchange or an iPod contact sync) to run. To enable Google sync client to operate as a full sync client, you have to change the client type from “app” to “server”. This will enable the “Sync now” button and will make sure Google sync is run every time a sync is run.

To change the Google sync client type, open a terminal window and type (one line)
sudo defaults write /System/Library/PrivateFrameworks/GoogleContactSync.framework/Resources/ClientDescription Type 'server'

Then type the following one line command to restore the permissions on the plist file:
sudo chmod 644 /System/Library/PrivateFrameworks/GoogleContactSync.framework/Resources/ClientDescription.plist

You can now go in Address Book’s preferences and enable Google contacts sync, without needing to enable Yahoo sync or plug an iPod for sync to work. Optionally go into iSync > Preferences and add the iSync menu to your menu bar. This let’s you see when it is syncing, and sync it manually.

Of course you can also initiate the synchronisation using the command line. Use this to run it periodically using launchd or cron:
/System/Library/PrivateFrameworks/GoogleContactSync.framework/Versions/A/Resources/gconsync --sync gconclid --register 1 --username user@gmail.com --password PASSWORD --syncmode fast

Wonder why this is a so mac centric post? On my Linux workstations I am using Sunbird in combination with the Provider for Google Calendar plugin and the Google contacts extension for Thunderbird since ages without having any trouble. But getting the the Apple stuff to work right with Google took me quite some time. Kudos to Michael Shick!