move ios sqlite database when updating app

Question

I'm using core-data in my app, and I want to start iTunes filesharing in next update, but need to move my apps sqlite database first. I have tried with the code below, but the app crashes on launch. I thought I could just replace the old store url with a new one in NSPersistentStoreCoordinator, where "newDatabasePath" matches the new store url.

then replace the sqlite file with

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

//check app has run before and has a current db
if ([saveData boolForKey:@"hasRunBefore"]) {
NSString *oldDatabasePath = [[dirPaths objectAtIndex:0] stringByAppendingPathComponent:@"AppData.sqlite"];
        NSString *newDatabasePath = [privateDocsPath stringByAppendingPathComponent:@"AppData.sqlite"];
        NSError *error;
        if ([fileMgr fileExistsAtPath:newDatabasePath]) {

            [fileMgr removeItemAtPath:newDatabasePath error:&error];
            [fileMgr copyItemAtPath:oldDatabasePath toPath:newDatabasePath  error:&error];
        }

        [fileMgr removeItemAtPath:oldDatabasePath error:&error];

        BOOL databaseMoved = YES;
        [saveData setBool:databaseMoved forKey:@"databaseMoved"];
}
}

Thanks

I tried a new approach to solve this with some success, after reading a similar question on here. I tried resetting the coredata stack like so

- (void)resetDatabase {

NSPersistentStore* store = [[__persistentStoreCoordinator persistentStores] lastObject];

NSError *error = nil;
NSURL *storeURL = store.URL;

// release context and model
__managedObjectModel = nil;
__managedObjectContext = nil;

//[__persistentStoreCoordinator removePersistentStore:store error:nil];

__persistentStoreCoordinator = nil;

NSFileManager* fileMgr = [NSFileManager defaultManager];
[fileMgr removeItemAtPath:storeURL.path error:&error];
if (error) {
    NSLog(@"filemanager error %@", error);
}

NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

//create Private Documents Folder
NSArray *libPaths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libDir = [libPaths objectAtIndex:0];
NSString *privateDocsPath = [libDir stringByAppendingPathComponent:@"Private Documents"];
if (![fileMgr fileExistsAtPath:privateDocsPath])
    [fileMgr createDirectoryAtPath:privateDocsPath withIntermediateDirectories:YES attributes:nil error:nil];


NSString *oldDatabasePath = [[dirPaths objectAtIndex:0] stringByAppendingPathComponent:@"AppData.sqlite"];
NSString *newDatabasePath = [privateDocsPath stringByAppendingPathComponent:@"AppData.sqlite"];

BOOL removedItemAtPath = NO;
BOOL copiedItemToPath = NO;

if ([fileMgr fileExistsAtPath:newDatabasePath]) {
    DLog(@"DATABASE EXISTS AT PATH");
    removedItemAtPath = [fileMgr removeItemAtPath:newDatabasePath error:&error];
    if (removedItemAtPath) {
        DLog(@"ITEM REMOVED");
    }
    else
        DLog(@"FAILED TO REMOVE ITEM: %@", error);

    copiedItemToPath = [fileMgr copyItemAtPath:oldDatabasePath toPath:newDatabasePath  error:&error];
    if (copiedItemToPath) {
        DLog(@"ITEM COPIED");
    }
    else
        DLog(@"FAILED TO COPY ITEM: %@", error);
}

// recreate the stack
__managedObjectContext = [self managedObjectContext];

}

With this approach, the app still throws an exception when trying to load data from the coredata stack when I first launch it, but then subsequently reloads everything ok, and uses the sqlite file from it's new location in "Library/Private Documents"

Answer 1

Since you said that the error message was:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array' *** First throw call stack:

That points the finger pretty strongly at this line:

NSString *oldDatabasePath = [[dirPaths objectAtIndex:0] stringByAppendingPathComponent:@"AppData.sqlite"];

The error message tells you why, too-- you're using index 0 on an empty array. So, dirPaths is empty. I don't know why, since you didn't post the code where you give it a value, but that's the cause of this crash.

Answer 2

The answer turned out to be simple as it usually does!

I just moved the code I needed to copy the apps original database into - (NSPersistentStoreCoordinator *)persistentStoreCoordinator before the store is added rather than trying to do it from - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions.

There goes another wasted day!

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{

if (__persistentStoreCoordinator != nil)
{
    return __persistentStoreCoordinator;
}

//test if app already run before, copy database over and remove old one, finally switch store url to new directory
if ([saveData boolForKey:@"hasRunBefore"]) {

    if ([saveData boolForKey:@"databaseUpdated"] != YES) {

        DLog(@"MOVING DATABASE");
        NSFileManager* fileMgr = [[NSFileManager alloc] init];
        fileMgr.delegate = self;
        NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *docsDir = [dirPaths objectAtIndex:0];
        //create Private Documents Folder
        NSArray *libPaths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
        NSString *libDir = [libPaths objectAtIndex:0];
        NSString *privateDocsPath = [libDir stringByAppendingPathComponent:@"Private Documents"];
        if (![fileMgr fileExistsAtPath:privateDocsPath])
            [fileMgr createDirectoryAtPath:privateDocsPath withIntermediateDirectories:YES attributes:nil error:nil];

        NSString *oldDatabasePath = [docsDir stringByAppendingPathComponent:@"AppData.sqlite"];
        NSString *newDatabasePath = [privateDocsPath stringByAppendingPathComponent:@"AppData.sqlite"];
        NSError *error;
        //BOOL removedItemAtPath = NO;
        BOOL copiedItemToPath = NO;

        copiedItemToPath = [fileMgr copyItemAtPath:oldDatabasePath toPath:newDatabasePath  error:&error];
        if (copiedItemToPath) {
            DLog(@"ITEM COPIED");
        }
        else
            DLog(@"FAILED TO COPY ITEM: %@", error);

        [fileMgr removeItemAtPath:oldDatabasePath error:&error];

        [saveData setBool:YES forKey:@"databaseUpdated"];
        [saveData synchronize];

    }

}


//NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"AppData.sqlite"];
NSURL *storeURL = [[self applicationHiddenDocumentsDirectory] URLByAppendingPathComponent:@"AppData.sqlite"];

NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
{
    DLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}    

return __persistentStoreCoordinator;
}

Answer 3

I had the same issue and found a very simple solution. Basically, before you initialize your NSPersistentStoreCoordinator, like at the top of - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions, move the database files from their current location to the new location. Make sure that you create the new location if it doesn't yet exist. In my sample code below I use a Database subdirectory under the Library/Application Support directory. I didn't show the creation of the "Database" directory; but, that also must occur before the files are moved. Make sure that your store initialization uses the new location.

NSURL *storeURL = [NSURL fileURLWithPath:[self getFullPrivatePath:@"<Database file name>"]];

Here's some code to help make this clear. I included my helper methods as well so there wasn't any confusion about where the methods came from or how they work. Note that there are 3 database files that must be moved which is why there is a loop. They are [database file name], [database file name]-wal, and [database file name]-shm.

- (void)convertPublicFilesToPrivate
{
    NSFileManager *fileManager = [NSFileManager defaultManager];

    // Move the database files
    NSArray<NSString *> *dbFiles = [self filesByPrefix:@"<database file name>" isPublic: YES];
    for (NSString *dbFile in dbFiles) {
        NSString *fileName = [dbFile lastPathComponent];
        NSError *error;
        NSString *privatePath = [self getFullPrivatePath:fileName];
        [fileManager moveItemAtPath: dbFile toPath: privatePath error:&error];
        NSLog(@"Move database file %@ returned %@", fileName, error);
    }
}

-(NSString *)getPublicPath
{
    return NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
}

- (NSString *)getPrivatePath
{
    return [NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES)[0] stringByAppendingPathComponent:@"Database"];
}

-(NSString*)getFullPublicPath:(NSString *)fileName
{
    NSString *documentsDirectory = [self getPublicPath];
    if (fileName != nil) {
        return [documentsDirectory stringByAppendingPathComponent:fileName];
    } else {
        return documentsDirectory;
    }
}

-(NSString*)getFullPrivatePath:(NSString *)fileName
{
    NSString *documentsDirectory = [self getPrivatePath];
    if (fileName != nil) {
        return [documentsDirectory stringByAppendingPathComponent:fileName];
    } else {
        return documentsDirectory;
    }
}

- (NSArray*)filesByPrefix:(NSString*)prefix isPublic:(BOOL)isPublic
{
    NSString *documentsDirectory = isPublic ? [self getPublicPath] : [self getPrivatePath];
    NSArray<NSString *> *directoryContent = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsDirectory error:NULL];
    NSMutableArray *fileList = [[NSMutableArray alloc] initWithCapacity:1];
    for (NSString *fileName in directoryContent) {
        if (prefix.length == 0 || [fileName hasPrefix:prefix]) {
            [fileList addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
        }
    }
    return fileList;
}