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Short version (TLDR): What are the general steps to integrate Ensembles into an app that is already set up to sync CoreData with iCloud via iCloud Drive? I am confused how I will be using Ensembles to facilitate the sync process.

Long Version: I'm a newbie programmer and I've hit a major wall with iCloud / CoreData syncing (seen here iOS 9 CoreData / ICloud - No such document at URL).

My app works perfectly with the exception of cloud syncing. Everything is configured properly to sync with icloud drive - and it works 99% of the time - but I get errors that break my app randomly and they come from apple's side of the code ("Librarian returned a serious error...").

All of my data is in coredata (sqlite) and my app is programmed in Swift 2.

Ensembles seems to be an option that will help solve my problem. However, I am at a complete loss of how to integrate it into my project. I am completely overwhelmed by the process of breaking apart my entire app. Can anyone offer some guidance of the steps I need to take? The manual and github readme are very in depth, but I am losing track of what I have to do. Overwhelming :(

In case it helps, below is my AppDelegate file, where I'm hoping all the work would need to be done...

//MARK: General
func backgroundThread(delay: Double = 0.0, background: (() -> Void)? = nil, completion: (() -> Void)? = nil) {
    dispatch_async(dispatch_get_global_queue(Int(QOS_CLASS_USER_INITIATED.rawValue), 0)) {
        if(background != nil){ background!(); }

        let popTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC)))
        dispatch_after(popTime, dispatch_get_main_queue()) {
            if(completion != nil){ completion!(); }
        }
    }
}


func applicationWillResignActive(application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
//

func applicationDidEnterBackground(application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    self.saveContext()

}

func applicationWillEnterForeground(application: UIApplication) {
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
    currentiCloudToken = NSFileManager.defaultManager().ubiquityIdentityToken

}

func applicationDidBecomeActive(application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.

}

func applicationWillTerminate(application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    // Saves changes in the application's managed object context before the application terminates.
    self.saveContext()
}

// MARK: - Core Data stack

lazy var managedObjectModel: NSManagedObjectModel = {
    // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
    let modelURL = NSBundle.mainBundle().URLForResource("Model", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: modelURL)!
    }()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    // The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
    // Create the coordinator and store
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)


    let documentsDirectory = NSFileManager.defaultManager().URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask).last as NSURL!

    let storeURL = documentsDirectory.URLByAppendingPathComponent("ArrivedAlive.sqlite")

    var error: NSError? = nil
    var failureReason = "There was an error creating or loading the application's saved data."
    let storeOptions = [NSPersistentStoreUbiquitousContentNameKey: "ArrivedAliveStore", NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]

    do {
        try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: storeURL, options: storeOptions)
    } catch var error1 as NSError {
        error = error1
        coordinator = nil
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        // Replace this with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog("Unresolved error \(error), \(error!.userInfo)")
        abort()
    } catch {
        fatalError()
    }

    return coordinator
    }()


lazy var managedObjectContext: NSManagedObjectContext? = {
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
    let coordinator = self.persistentStoreCoordinator
    if coordinator == nil {
        return nil
    }
    var managedObjectContext = NSManagedObjectContext(concurrencyType: NSManagedObjectContextConcurrencyType.MainQueueConcurrencyType)

    managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
    managedObjectContext.persistentStoreCoordinator = coordinator

    return managedObjectContext
    }()

// MARK: - Core Data Saving support

func saveContext () {
    if let moc = self.managedObjectContext {
        var error: NSError? = nil
        if moc.hasChanges {
            do {
                try moc.save()
            } catch let error1 as NSError {
                error = error1
                // Replace this implementation with code to handle the error appropriately.
                // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                NSLog("Unresolved error \(error), \(error!.userInfo)")
                abort()
            }
        }
    }
}

Thanks!

Community
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Charlie
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  • I strongly recommend reading the Quick Start chapter from the [free book](http://leanpub.com/ensembles). – Drew McCormack Nov 07 '15 at 08:06
  • After spending about 3 hours stressing about implementing Ensembles I was able to execute all changes in about 45 minutes! Your framework is AWESOME!! Thank you for making it! – Charlie Nov 07 '15 at 17:13

1 Answers1

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In truth, there is not all that much work required to add Ensembles to your stack. However, since you are "inexperienced" I would recommend that you not try to change your existing stack.

Instead, I would recommend that you rewrite your stack. It's not that much code. Use the Simple Sync example as your guide, as that application uses iCloud as its backend.

Once you have the stack setup, there is not much else you need to change in your application, except determining when you want to sync.

Jody Hagins
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  • Do you believe that errors such as "CoreData: Ubiquity: Librarian returned a serious error for starting downloads Error Domain=BRCloudDocsErrorDomain Code=6" and "CoreData: Ubiquity: Librarian returned a serious error for starting downloads Error Domain=BRCloudDocsErrorDomain Code=5 "No document at URL"" would be fixed by following that example? I was under the impression that there is something happening behind the scenes that I can't fix from these errors! – Charlie Oct 29 '15 at 15:01
  • Also, you mention "when you sync". Previously, this was all handled by iCloud itself so that is the exact area I am most confused about :( – Charlie Oct 29 '15 at 15:04
  • I only mention that because you can setup syncing to be initiated automatically on every save, or periodically, and/or manually. Just use that implementation as a reference, and you will see exactly what I'm talking about. – Jody Hagins Oct 29 '15 at 15:22
  • Thanks Jody - I appreciate your replies. To clarify - do you think Ensembles will assist with the errors I listed above in my first comment? or am I wishful thinking? – Charlie Oct 29 '15 at 15:24
  • I have used Ensembles extensively, and it is awesome. However, I have not personally used the iCloud backends, so I can't answer that. I do know that the iCloud backend is used by tons of people, and aside from the initial setup works the same as what I'm doing. – Jody Hagins Oct 29 '15 at 15:24
  • Ok, Thanks so much! I will move forward integrating Ensembles using the simple sync example from scratch. Wish me luck! – Charlie Oct 29 '15 at 15:25