Alternative to NSDistributedNotificationCenter for comms between iPhone apps - iphone

Question

I've been looking for a way to compare timestamps between applications on the same phone in real time, and NSDistributedNotificationCenter sounded like an ideal solution since i may not know the names of the apps listening for it, but it sounds like its not available in iOS.
Is there an equivalent way of notifying multiple apps of a time-sensitive event without knowing their name?
Coding for iOS 5+ and assuming the apps in question will register for the notification.

Answer 1

Look at CPDistributedMessagingCenter in /System/Library/PrivateFrameworks/AppSupport.framework. However, it's a private framework (may change with OS releases, and not allowed in AppStore).
Documentation here: http://iphonedevwiki.net/index.php/CPDistributedMessagingCenter
Example codes of mine here:
https://github.com/H2CO3/PwnTube
https://github.com/H2CO3/Cereal

Answer 2

I'm pretty sure you can use Mach ports. They are a bit low level but work well.

Answer 3

i found a way to use CFNotificationCenterGetDistributedCenter() on iOS. It is exists on device, but not exports in iOS SDK
void *libHandle = dlopen("/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation", RTLD_LAZY);
CFNotificationCenterRef (*CFNotificationCenterGetDistributedCenter)() = (CFNotificationCenterRef (*)())dlsym(libHandle, "CFNotificationCenterGetDistributedCenter");
if(CFNotificationCenterGetDistributedCenter) {
CFNotificationCenterAddObserver(CFNotificationCenterGetDistributedCenter(), NULL, &NotificationUpdateApp, CFSTR("TestApp"), NULL, CFNotificationSuspensionBehaviorCoalesce);
}
dlclose(libHandle);

Answer 4

Not really. The closest you can do to what you’re asking, on a non-jailbroken device, is have your server talk to each other app’s server and have that server send a push notification to the app in question. Without NSDistributedNotificationCenter (which is, as you surmise, not available on iOS), you don’t really have any other option.

Answer 5

This question is a little bit old, but I'll post my answer just for information purposes.
NSDistributedNotificationCenter is not available for iOS yet, and unless your are developing an app that you don'd pretend to release on AppStore, you can't use AppSupport.framework because it's private.
iOS8 released App Extensions, that give us the ability to communicate with other apps. I don't know what you are trying to do exactly but I believe that if you are just trying to compare some timestamps from some other apps, it should resolve your problem.
Link to AppExtensions documentation:
https://developer.apple.com/library/ios/documentation/General/Conceptual/ExtensibilityPG/
Hope it helps somebody.

Answer 6

NSDistributedNotificationCenter exists on iOS, but the headers aren't made available to developers.
Create a header file in your project with the following to make the class available:
#interface NSDistributedNotificationCenter : NSNotificationCenter
+ (NSDistributedNotificationCenter *)defaultCenter;
// Returns the default distributed notification center - cover for [NSDistributedNotificationCenter notificationCenterForType:NSLocalNotificationCenterType]
- (void)postNotificationName:(NSNotificationName)name object:(nullable NSString *)object userInfo:(nullable NSDictionary *)userInfo deliverImmediately:(BOOL)deliverImmediately;
#end
This is very useful when trying to get information from an App to its UITest runner, but you should obviously NOT attempt to put this in the AppStore.
I've created a project XCTestBackChannel to show this off.