I'm currently trying to get this set up to allow me to sync an array between devices.

In my AppDelegate I add

Zephyr.debugEnabled = true
Zephyr.addKeysToBeMonitored(keys: "defaultToSync")
Zephyr.sync(keys: "defaultToSync")

Which when launching the second device will pull in what value has been set.

I then change the value using:

UserDefaults().set(value, forKey: "defaultToSync")
Zephyr.sync(keys: "defaultToSync")

My second device never seems to pick up that things have changed, the device making the change does say it has synced TO iCloud.

My understanding is that the key being monitored should at some point see the change?

Any help is appreciated.

Added an optional parameter to Zephyr.sync(), taking a custom UserDefaults object and using that in place of always using the container-wide UserDefaults.standard.

Fixed bug resulting in UserDefaults.standard being used despite passing in a custom UserDefaults object to the variable-arguments sync() function (when no keys were passed in)

I am just getting started with Zephyr, I want to use it sync my UserDefaults between iPad and iOS version of my app. I have set it up, and it doesn't seem to find the values across devices. Both devices are logged into the same iCloud account, and in debug mode I see that Zephyr is syncing - but each devices seems to find a unique instance. (this is in the simulator on both devices). Is this addressed via a UserDefaults SuiteName?

This PR will remain open until Xcode 8.0 GM is released.

Initial conversion to Swift 3 was done in Xcode 8.0b2.

All work for Swift 3 compatibility will be done in this branch.

All parts of the guard statement have been split into let statements and two separate if statements.

If localStoredData == nil we still want to synchronize.

See issue #48.

Sorry for my late response. answering your question here: https://github.com/ArtSabintsev/Zephyr/issues/45#event-2843850328

first in: func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?)

I register defaults, where:

let emptyData = Data()
UserDefaults.standard.register(defaults: [subscription.identifier: emptyData])
Zephyr.addKeysToBeMonitored(keys: [subscription.identifier])

later after checking the status of the user subscription I store the subscription in UserDefaults to later sync:

let encoder = PropertyListEncoder()
let statusData = try! encoder.encode(status)                
UserDefaults.standard.set(statusData, forKey: subscription.identifier)
Zephyr.sync(keys: [subscription.identifier])

And here is where the override issue happens. I managed to fix it in my phone by removing the key from iCloud with NSUbiquitousKeyValueStore.default.removeObject(forKey:) But trying with a different phone happen again.

If you could give me some hint here I would really appreciated

Initially, when I reported this issue, I thought it was due to a synchronization timing / data race issue, but I have since found otherwise.

It appears that the date stored in zephyrRemoteStoreDictionary[ZephyrSyncKey] often supplies the incorrect time, thus causing data lost for the local store. Although I have yet to pinpoint the cause of the issue, this key fairly consistently (2 out of every 3 calls) reports a time that is ahead of the local time. Unfortunately, this means that when updating a default in the local store that is newer than the default stored remotely, the older remote value trumps the new local value.

I will continue looking into the issue and see if I can find out any additional information. Hopefully we can get this fixed!

Thank you for this project - saved me a good chunk of time, and it's beautifully written! 🍻

Hey Arthur!

Just loaded this up in Xcode 8 beta 4 and I'm getting this error on line 75.

Use of unresolved identifier 'DispatchQueueAttributes'

private let zephyrQueue = DispatchQueue(label: "com.zephyr.queue", attributes: DispatchQueueAttributes.serial);

It looks like this initializer is only available in iOS 10+.

Is it iOS thing only, viz. doc: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIApplication_Class/#//apple_ref/c/data/UIApplicationWillEnterForegroundNotification

First off: Thank you for this library. This is exactly what I was looking for.

There seems to be a sync issue with macOS Monterey (tested version: 12.0.1 (21A558))

It seems that Apple changed the behavior on how it posts the NSUbiquitousKeyValueStore.didChangeExternallyNotification notification.

Formerly, notification.userInfo?[NSUbiquitousKeyValueStoreChangedKeysKey] contained ALL changed keys (including ZephyrSyncKey). In my tests, this is no longer the case. Instead, the notification gets posted multiple times, with different values. Here is what happens in my scenario:

We have Client A and Client B. Lets say A changes 2 keys. What happens is:

Zephyr:

• Receives NSUbiquitousKeyValueStore.didChangeExternallyNotification notification for key 1, stores remote value to local user defaults.
• Zeyphr sets local sync date
• Receives NSUbiquitousKeyValueStore.didChangeExternallyNotification notification for key 2, throws it away, because local sync date is newer
• Receives NSUbiquitousKeyValueStore.didChangeExternallyNotification notification for key ZephyrSyncKey

https://github.com/ArtSabintsev/Zephyr/blob/d86fe8ccc70b599ffd9adde55ada042910d045a1/Sources/Zephyr.swift#L456-L459

In this scenario, the second value was thrown out and both apps are no longer in sync.

I can't tell if this is a (beta) bug or if this is the new, expected behavior. I can't think of a good way to fix this, as we would now need to store the sync date of each property - or somehow batch all those updates coming in.

This fixes a couple of issues that prevent the package from compiling with current versions of Swift and Xcode:

• commit 6357a65:
  • updates Package.swift format to 4.0 as required by Swift 5 (and recommended for Swift 4)
• commit 9ba6be1:
  • tracks the .UIApplicationWillEnterForeground notification name change (Swift 4.2 onwards)
• commit eae57a6:
  • protects UIKit specifics with #if os() so Zephyr now compiles for macOS as well