Tuesday, March 10, 2015
Google Drive API Push Notifications
If your app needs to keep up with changes in Drive, whether to sync files, initiate workflows, or just keep users up to date with the latest info, you’re likely familiar with Drive’s changes feed. But periodic polling for changes has always required a delicate balance between resources and timeliness.
Now there’s a better way. With push notifications for the Drive API, periodic polling is no longer necessary. Your app can subscribe for changes to a user’s drive and get notified whenever changes occur.
Suppose your app is hosted on a server with my-host.com domain and push notifications should be delivered to an HTTPS web-hook https://my-host.com/notification:
String subscriptionId = UUID.randomUUID().toString();
Channel request = new Channel()
.setId(subscriptionId)
.setType("web_hook")
.setAddress("https://my-host.com/notification");
drive.changes().watch(request).execute();
As long as the subscription is active, Google Drive will trigger a web-hook callback at https://my-host.com/notification. The app can then query the change feed to catch up from the last synchronization point:
changes = service.changes().list()
.setStartChangeId(lastChangeId).execute();
If your app only needs to be notified about changes to a particular file or folder your app can watch just those files rather than the entire change feed.
If you are interested in using this new feature, please refer to the documentation at developers.google.com. You can see push notifications in action with the Push Notifications Playground and view the source at Github.
 | Steven Bazyl profile | twitter Steve is a Developer Advocate for Google Drive and enjoys helping developers build better apps. |
