[英]iOS 11+ How to migrate existing Core Data to Shared App Group for use in extension?
When I created an iOS 11 app using the core data template, it auto generated the following code in AppDelete.m.当我使用核心数据模板创建 iOS 11 应用程序时,它会在 AppDelete.m 中自动生成以下代码。
synthesize persistentContainer = _persistentContainer;
- (NSPersistentContainer *)persistentContainer {
// The persistent container for the application. This implementation creates and returns a container, having loaded the store for the application to it.
@synchronized (self) {
if (_persistentContainer == nil) {
_persistentContainer = [[NSPersistentContainer alloc] initWithName:@"My_History"];
[_persistentContainer loadPersistentStoresWithCompletionHandler:^(NSPersistentStoreDescription *storeDescription, NSError *error) {
if (error != nil) {
// 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.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
NSLog(@"Unresolved error %@, %@", error, error.userInfo);
abort();
}
}];
}
}
return _persistentContainer;
}
- (void)saveContext {
NSManagedObjectContext *context = self.persistentContainer.viewContext;
NSError *error = nil;
if ([context hasChanges] && ![context save:&error]) {
// 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();
}
I would like to add a Today and iMessage extension that accesses the history in the core data.我想添加一个访问核心数据历史记录的 Today 和 iMessage 扩展。 From what I read, I need to migrate this data if it exists to a shared app container.
根据我阅读的内容,如果此数据存在,我需要将其迁移到共享应用程序容器中。 How would I do that?
我该怎么做?
The code is in objective C.代码在目标 C 中。
I have read other questions involving this but all of them seem to be before Apple changed the way core data works to make it easier.我已经阅读了其他涉及此问题的问题,但所有这些问题似乎都是在 Apple 改变核心数据的工作方式以使其更容易之前。 As you can see in my code, I never specified what the data store exact file name is.
正如您在我的代码中看到的那样,我从未指定数据存储的确切文件名是什么。 Every example I saw had something like "My_History.sqllite".
我看到的每个示例都有类似“My_History.sqllite”的内容。 I don't even know if mine is a sql lite database, it was just created by that code.
我什至不知道我的是否是 sql lite 数据库,它只是由该代码创建的。
solidsnake4444 's answer saves my day. solidsnake4444的回答节省了我的时间。 Here is the Swift 5.0 version.
这是 Swift 5.0 版本。
lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "MyApp")
let storeURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.my.app")!.appendingPathComponent("MyApp.sqlite")
var defaultURL: URL?
if let storeDescription = container.persistentStoreDescriptions.first, let url = storeDescription.url {
defaultURL = FileManager.default.fileExists(atPath: url.path) ? url : nil
}
if defaultURL == nil {
container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: storeURL)]
}
container.loadPersistentStores(completionHandler: { [unowned container] (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
if let url = defaultURL, url.absoluteString != storeURL.absoluteString {
let coordinator = container.persistentStoreCoordinator
if let oldStore = coordinator.persistentStore(for: url) {
do {
try coordinator.migratePersistentStore(oldStore, to: storeURL, options: nil, withType: NSSQLiteStoreType)
} catch {
print(error.localizedDescription)
}
// delete old store
let fileCoordinator = NSFileCoordinator(filePresenter: nil)
fileCoordinator.coordinate(writingItemAt: url, options: .forDeleting, error: nil, byAccessor: { url in
do {
try FileManager.default.removeItem(at: url)
} catch {
print(error.localizedDescription)
}
})
}
}
})
return container
}()
I ended up getting it doing the following.我最终得到它执行以下操作。 The sqlite file was actually the name of my init plus .sqlite at the end.
sqlite 文件实际上是我的 init 名称加上最后的 .sqlite。
+ (NSPersistentContainer*) GetPersistentContainer {
//Init the store.
NSPersistentContainer *_persistentContainer = [[NSPersistentContainer alloc] initWithName:@"Test_App"];
//Define the store url that is located in the shared group.
NSURL* storeURL = [[[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:@"group.Test_App"] URLByAppendingPathComponent:@"Test_App.sqlite"];
//Determine if we already have a store saved in the default app location.
BOOL hasDefaultAppLocation = [[NSFileManager defaultManager] fileExistsAtPath: _persistentContainer.persistentStoreDescriptions[0].URL.path];
//Check if the store needs migration.
BOOL storeNeedsMigration = hasDefaultAppLocation && ![_persistentContainer.persistentStoreDescriptions[0].URL.absoluteString isEqualToString:storeURL.absoluteString];
//Check if the store in the default location does not exist.
if (!hasDefaultAppLocation) {
//Create a description to use for the app group store.
NSPersistentStoreDescription *description = [[NSPersistentStoreDescription alloc] init];
//set the automatic properties for the store.
description.shouldMigrateStoreAutomatically = true;
description.shouldInferMappingModelAutomatically = true;
//Set the url for the store.
description.URL = storeURL;
//Replace the coordinator store description with this description.
_persistentContainer.persistentStoreDescriptions = [NSArray arrayWithObjects:description, nil];
}
//Load the store.
[_persistentContainer loadPersistentStoresWithCompletionHandler:^(NSPersistentStoreDescription *storeDescription, NSError *error) {
//Check that we do not have an error.
if (error == nil) {
//Check if we need to migrate the store.
if (storeNeedsMigration) {
//Create errors to track migration and deleting errors.
NSError *migrateError;
NSError *deleteError;
//Store the old location URL.
NSURL *oldStoreURL = storeDescription.URL;
//Get the store we want to migrate.
NSPersistentStore *store = [_persistentContainer.persistentStoreCoordinator persistentStoreForURL: oldStoreURL];
//Set the store options.
NSDictionary *storeOptions = @{ NSSQLitePragmasOption : @{ @"journal_mode" : @"WAL" } };
//Migrate the store.
NSPersistentStore *newStore = [_persistentContainer.persistentStoreCoordinator migratePersistentStore: store toURL:storeURL options:storeOptions withType:NSSQLiteStoreType error:&migrateError];
//Check that the store was migrated.
if (newStore && !migrateError) {
//Remove the old SQLLite database.
[[[NSFileCoordinator alloc] init] coordinateWritingItemAtURL: oldStoreURL options: NSFileCoordinatorWritingForDeleting error: &deleteError byAccessor: ^(NSURL *urlForModifying) {
//Create a remove error.
NSError *removeError;
//Delete the file.
[[NSFileManager defaultManager] removeItemAtURL: urlForModifying error: &removeError];
//If there was an error. Output it.
if (removeError) {
NSLog(@"%@", [removeError localizedDescription]);
}
}
];
//If there was an error. Output it.
if (deleteError) {
NSLog(@"%@", [deleteError localizedDescription]);
}
}
}
} else {
// 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.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
NSLog(@"Unresolved error %@, %@", error, error.userInfo);
abort();
}
}];
//Return the container.
return _persistentContainer;
}
UPDATE:更新:
To migrating an existing persistent store, the NSPersistentContainer
contains the persistentStoreCoordinator
, an instance of NSPersistentStoreCoordinator
.为了迁移现有的持久化存储,
NSPersistentContainer
包含了persistentStoreCoordinator
,它是NSPersistentStoreCoordinator
的一个实例。 This exposes the method migratePersistentStore:toURL:options:withType:error:
to migrate a persistent store.这公开了
migratePersistentStore:toURL:options:withType:error:
方法来迁移持久存储。
I would do the following:我会做以下事情:
// Get the reference to the persistent store coordinator
let coordinator = persistentContainer.persistentStoreCoordinator
// Get the URL of the persistent store
let oldURL = persistentContainer.persistentStoreDescriptions.url
// Get the URL of the new App Group location
let newURL = NSFileManager.defaultManager().containerURLForSecurityApplicationGroupIdentifier("YOUR_APP_GROUP")
// Get the reference to the current persistent store
let oldStore = coordinator.persistentStore(for: oldURL)
// Migrate the persistent store
do {
try coordinator.migratePersistentStore(oldStore, to: newURL, options: nil, withType: NSSQLiteStoreType)
} catch {
// ERROR
}
Please note that the above hasn't been tested and I haven't handled Optionals so it isn't complete.请注意,以上内容尚未经过测试,并且我没有处理 Optionals,因此它不完整。 Also, I apologise for it being in Swift.
另外,我很抱歉它在 Swift 中。 Hopefully it is easy enough for you to write the equivalent in Objective-C.
希望你可以很容易地用 Objective-C 编写等价的代码。
ORIGINAL:原来的:
The following outlines how to create an NSPersistentContainer
interfacing to a persistent store in a non-default location.下面概述了如何创建一个
NSPersistentContainer
接口到一个非默认位置的持久存储。
The NSPersistentContainer
exposes the defaultDirectoryURL
, and states: NSPersistentContainer
公开了defaultDirectoryURL
,并声明:
This method returns a platform-dependent
NSURL
at which the persistent store(s) will be located or are currently located.此方法返回一个依赖于平台的
NSURL
,持久存储将位于或当前位于该 NSURL。 This method can be overridden in a subclass ofNSPersistentContainer
.可以在
NSPersistentContainer
的子类中重写此方法。
If you subclass NSPersistentContainer
and define the defaultDirectoryURL
to be an App Group directory using containerURLForSecurityApplicationGroupIdentifier
, you should then be able to access the container between your application and extensions (assuming they have the same App Group entitlements).如果您将
NSPersistentContainer
子类化并使用containerURLForSecurityApplicationGroupIdentifier
将defaultDirectoryURL
定义为 App Group 目录,那么您应该能够访问您的应用程序和扩展之间的容器(假设它们具有相同的 App Group 权利)。
NSPersistentContainer
also exposes persistentStoreDescriptions
which also features a URL instance. NSPersistentContainer
还公开了还具有 URL 实例的persistentStoreDescriptions
。 Likewise, you may be able to update this to the App Group URL before calling loadPersistentStoresWithCompletionHandler:
.同样,您可以在调用
loadPersistentStoresWithCompletionHandler:
之前将其更新为 App Group URL。
Note that I have not used NSPersistentContainer
, and have no idea whether this sharing would cause any concurrency issues.请注意,我没有使用
NSPersistentContainer
,并且不知道这种共享是否会导致任何并发问题。
When moving NSPersistentCloudKitContainer
, this is what worked for me.移动
NSPersistentCloudKitContainer
时,这对我有用。 A couple things to watch out for:有几点需要注意:
cloudKitContainerOptions
is set on the persistent store description otherwise sync will stop workingcloudKitContainerOptions
否则同步将停止工作migratePersistentStore
otherwise you'll end up with duplicate records, instead use replacePersistentStore
- see this thread for more infomigratePersistentStore
否则你会得到重复的记录,而是使用replacePersistentStore
- 有关更多信息,请参阅此线程destroyPersistentStore
sounds promising but doesn't seem to actually delete the files - see this questiondestroyPersistentStore
听起来很有希望,但似乎并没有真正删除文件 - 请参阅此问题struct PersistenceController {
static let shared = PersistenceController()
let container: NSPersistentCloudKitContainer
init(inMemory: Bool = false) {
container = NSPersistentCloudKitContainer(name: "MyCuteDB")
if inMemory {
container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
} else {
// Use App Groups so app and extensions can access database
let sharedStoreURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.yourdomain.yourapp")!.appendingPathComponent("\(container.name).sqlite")
let defaultStoreURL = container.persistentStoreDescriptions.first!.url! //the URL always starts out in the default location
// move database to shared location if needed
if FileManager.default.fileExists(atPath: defaultStoreURL.path) && !FileManager.default.fileExists(atPath: sharedStoreURL.path) {
let coordinator = container.persistentStoreCoordinator
do {
try coordinator.replacePersistentStore(at: sharedStoreURL, destinationOptions: nil, withPersistentStoreFrom: defaultStoreURL, sourceOptions: nil, ofType: NSSQLiteStoreType)
try? coordinator.destroyPersistentStore(at: defaultStoreURL, ofType: NSSQLiteStoreType, options: nil)
// destroyPersistentStore says it deletes the old store but it actually truncates so we'll manually delete the files
NSFileCoordinator(filePresenter: nil).coordinate(writingItemAt: defaultStoreURL.deletingLastPathComponent(), options: .forDeleting, error: nil, byAccessor: { url in
try? FileManager.default.removeItem(at: defaultStoreURL)
try? FileManager.default.removeItem(at: defaultStoreURL.deletingLastPathComponent().appendingPathComponent("\(container.name).sqlite-shm"))
try? FileManager.default.removeItem(at: defaultStoreURL.deletingLastPathComponent().appendingPathComponent("\(container.name).sqlite-wal"))
try? FileManager.default.removeItem(at: defaultStoreURL.deletingLastPathComponent().appendingPathComponent("ckAssetFiles"))
})
} catch {
//TODO: Handle error
}
}
// change URL from default to shared location
container.persistentStoreDescriptions.first!.url = sharedStoreURL
let description = container.persistentStoreDescriptions.first!
description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.yourdomain.yourapp")
}
container.loadPersistentStores { description, error in
//TODO: Handle error
}
container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
container.viewContext.automaticallyMergesChangesFromParent = true
}
}
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