Swift CloudKit CoreData 远程更改通知也针对本地更改触发

Question

我有一个带有 Local 存储和 Cloud 存储的 CoreData 设置，只有后者与 [=38= 同步].同步本身运行良好。

我正在尝试监听远程更改通知，以便当来自 CloudKit 的远程更改进入时，我可以在设备上触发一些进程。我已经设置了 NSPersistentStoreRemoteChangeNotificationOptionKey 键我的持久性控制器，以及相应的监听器。

观察者正确触发远程更改通知，但我的问题是，一旦保存视图上下文，也会触发设备上产生的任何 CoreData 更改。

如果这是预期的行为，我希望通知本身至少会有一些有用的信息，这样我就可以区分更改是由设备上的操作触发的还是从 CloudKit 同步的.

有没有我做错了什么，或者有任何其他简单的方法可以在发生远程更改时收到通知？

持久化控制器

struct PersistenceController {
    static let shared = PersistenceController()
        
    let container: NSPersistentCloudKitContainer
    
    init() {
        container = NSPersistentCloudKitContainer(name: "MyContainerName")
        
        let storeDirectory = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first!
        
        // Local
        let localUrl = storeDirectory.appendingPathComponent("local.store")
        let local = NSPersistentStoreDescription(url: localUrl)
        local.configuration = "Local"
        
        // Cloud
        let cloudUrl = storeDirectory.appendingPathComponent("cloud.store")
        let cloud = NSPersistentStoreDescription(url: cloudUrl)
        cloud.configuration = "Cloud"
        cloud.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "my.container.identifier")
        cloud.setOption(true as NSNumber, forKey: "NSPersistentStoreRemoteChangeNotificationOptionKey")
        
        container.persistentStoreDescriptions = [local, cloud]
        
        container.loadPersistentStores(completionHandler: { (storeDescription, error) in
            if let error = error as NSError? {
                fatalError("Unresolved error \(error), \(error.userInfo)")
            }
        })
        
        container.viewContext.automaticallyMergesChangesFromParent = true
        container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
        
    }    
}

应用委托

class AppDelegate: NSObject, UIApplicationDelegate {
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        
        NotificationCenter.default.addObserver(
            self, selector: #selector(type(of: self).storeRemoteChange(_:)),
            name: .NSPersistentStoreRemoteChange,
            object: PersistenceController.shared.container.persistentStoreCoordinator
        )
        return true
    }
    
    @objc
    func storeRemoteChange(_ notification: Notification) {
        
        precondition(notification.name == NSNotification.Name.NSPersistentStoreRemoteChange)

        print(notification.userInfo)
        
    }
    
}

打印语句的输出

Optional([AnyHashable("NSStoreUUID"): C2D121212-421B-003F-9819-956411111169, AnyHashable("storeURL"): file:///var/mobile/Containers/Data/Application/3234FH#-DACF-493I-AD24-143E4CDSFE2/Library/Application%20Support/cloud.store])

Answer 1

If this is expected behaviour, I was hoping there would at least be some useful information in the notification itself so I could tell apart whether the change was triggered by an on-device action or synced from CloudKit.

是的，这是预期的行为，因为无论是在本地设备上还是从云中更改，这都会记录为您 store/database 中的更改。

因此，为了处理来自云的更改，您可以订阅数据库更改，阅读 here

Swift CloudKit CoreData 远程更改通知也针对本地更改触发

Swift CloudKit CoreData Remote Change Notification also firing for local changes

ios

swift

core-data

cloudkit

持久化控制器

应用委托

打印语句的输出