How can two mobile devices communicate using GAE iOS endpoints

Question

I'm learning how to build a mobile app with Google App Engine's iOS endpoints (python backend). I'm a noob.

From all of the documentation I've found, communication between the mobile device and the GAE backend-datastore occurs in a query-response format to-and-from a single device. But now I would like an action by one device to cause the server to send information to another device.

I saw a tutorial on CloudActionDelegate that seems to suit my needs, but I'm getting the impression that it has been deprecated. It also looks like APNs are not really what I'm looking for because I'm would like to provide frequent updates (for example, anytime one device moves).

Answer 1

You have two choices for receiving updates from a server on iOS. Both are documented at https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html

1. Use the fetch background mode to wake up periodically and query the server to see if there's an update. (See "Fetching Small Amounts of Content Opportunistically")
2. Push notifications. (See "Using Push Notifications to Initiate a Download")

Note that neither of these options allows the GAE server to directly communicate with your iOS app. In both cases, the system wakes your app up and says "hey, someone has some data for you." Then your app goes and gets it.