Amazon Simple Notification Service (SNS) for push notifications on iOS?

Question

Amazon Web Services have an SDK for iOS which supports the Amazon Simple Notification Service (SNS).

Does this mean it would be possible to use SNS to send push notifications to a running iOS app? So for example you could make an real-time instant messaging app.

Is this right, or have I misunderstood what SNS does? It just seems to me that you would need to open a connection/socket in order to recieve push notifications from your server. How does the SDK actually work?

Update:

I've since asked this question on the AWS Mobile Development Forum: https://forums.aws.amazon.com/thread.jspa?threadID=81089&tstart=0

Apparently there is an article coming out (probably here: http://aws.amazon.com/articles/SDKs/iOS) shortly to explain everything.

Update 2 The article: http://aws.amazon.com/articles/9156883257507082

Answer 1

According to Apple documentation "Local notifications and push notifications are ways for an application that isn’t running in the foreground to let its users know it has information for them.".

So, technically speaking, any data, including notifications, received when the application is running in the foreground are not "Push Notifications" and can't be a reason for rejecting the application. They're simply data being consumed that way or the other by the application.

In this specific case you are not asking about Push Notifications per Apple's documentation, rather about a technology used to deliver data to the application when the application is running and user is interacting with it. It happens that the name Amazon SNS is similar to Push Notification.

In any case Apple wouldn't be able to see what is the technology behind delivering data to your application, whether it is Amazon SNS or anything else. All they can see is that the application may have some additional ports open when it's running, and that of course would be absolutely legal. In fact, many applications communicate with their back-end servers using sockets (not HTTP requests), and that is the same technology as used by Apple to deliver their Push Notifications.