Friend request real time notification to recipient device - objective-c

Question

I want to notify a user if any other user wants to be friend with him. The only ways I can currently think of is notify through push notifications or recipients device will keep polling server for new information at certain frequency or device will check for new information only when it launches.
I have some problems with Push Notifications method to send requests
If device is offline only last notification will get processed
If app is not running, push notification will get delivered in Notifications and I don't know how can I extract information from there to my app.
Also, if device keeps polling for new information number of API calls will be very high which is not cost effective and alternately if device asks for new information only at start up launch it will not get real time updates.
Is there any way I can send information to device as soon as information is available?.
Any suggestions will be appreciated

Answer 1

Have you taken a look at Urban Airship?
They have a great framework set up for queueing and receiving push notifications, even when your app is offline. You can either queue the notification from the app itself or from your server hosting your account data. They also have the ability to compose and push rich content notifications.
The basic account for small apps gets 1 million free push notifications per month. Everything beyond that is fractions of a penny.
Hope this helps, Cheers!

Answer 2

Notifications is one such thing which can drain down battery if one takes polling route, thats one of the reasons Apple developed Push Notifications. I would recommend try to use Apple Push notification as much as possible as it would have been optimized to hell. If you have different flows for when the app is active & for when the app is not active (reg. notifications) you can do it like so -
- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
{
if(application.applicationState == UIApplicationStateActive) {
// app active.
}
else {
// app not active
}
}
But if in any case Apples Technology does not suite ones needs one could always use third party services. In this case there are a few that can really help you.
Pusher has an Objective-C library and a REST API (along with a number of libraries) that would let you push realtime updates from your server into an iOS application.
OpenPush is another such service. Also check this link, here's a compiled list of realtime technologies in which I'm sure you'll also find technologies that meet your requirements.
All of these are better than polling.

Answer 3

Is there any way I can send information to device as soon as information is available?. Any suggestions will be appreciated
user1 wants to add user2 as friend.
from device, post information to server, in your webscript, process the friend request of user1 to user2 (insert/update information to database etc), when done. send the notification to user2. this will work if the device is offline, user2 will have real time update, if the app is running. you can run scheduled request that will check new notifications. say every 2 minutes, a method in your app runs. but thats not a very good idea. A reload button inside the app to check notification is better.

Answer 4

What you would normally do is to use the push request as a means of informing your app that new data is available. The user clicks on the push notification - the app is opened with the
-(void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
you register that there was push, query your server and the server let's your app know that this list of new friend requests are there.
You can't really do the queuing of messages on the device - and you don't need to. It's much easier to just store the info on your server until the app queries it.