iOS Data Storage issue - Rejected even after NSURLIsExcludedFromBackupKey - ios

Question

My app is rejected from app store multiple times for not following 'iOS Data Storage Guidelines'. I have marked all document directories with "do not back up" attribute as suggested by apple review team, as shown:
- (BOOL)addSkipBackupAttributeToItemAtPath:(NSString *) filePathString
{
NSURL* URL= [NSURL URLWithString:filePathString];
NSError *error = nil;
BOOL success = [URL setResourceValue: [NSNumber numberWithBool: YES]
forKey: NSURLIsExcludedFromBackupKey error: &error];
return success;
}
I have called the above addSkipBackupAttributeToItemAtPath method for all NSDocumentDirectory as shown :
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
[self addSkipBackupAttributeToItemAtPath:[paths objectAtIndex:0]];
and review team says it is still storing some data as backup to iCloud and it is being rejected by Apple review team, actually i don't want anything to back up. Is there anything i have missed to Skip Backup Attribute? or anything wrong in my code? please help. Thank you.

Answer 1

Write this code in addSkipBackupAttributeToPath method. I had the same issue and was resolved by writing this code instead.
- (void)addSkipBackupAttributeToPath:(NSString*)path
{
u_int8_t b = 1;
setxattr([path fileSystemRepresentation], "com.apple.MobileBackup", &b, 1, 0, 0);
}

Answer 2

Try using the NSCachesDirectory instead of the NSDocumentDirectory, to store the subfolders/files.

Answer 3

Even though i am using 'do not back up' attribute i was storing the downloadable contents in \Documents directory, so as per the priority \Documents contents will automatically backed up to icloud.
Apple doc says:
Only documents and other data that is user-generated, or that cannot
otherwise be recreated by your application, should be stored in the
/Documents directory and will be automatically backed up by iCloud.
Data that can be downloaded again or regenerated should be stored in
the /Library/Caches directory. Examples of files you
should put in the Caches directory include database cache files and
downloadable content, such as that used by magazine, newspaper, and
map applications.
Data that is used only temporarily should be stored in the
/tmp directory. Although these files are not backed
up to iCloud, remember to delete those files when you are done with
them so that they do not continue to consume space on the user’s
device.
Use the "do not back up" attribute for specifying files that should
remain on device, even in low storage situations. Use this attribute
with data that can be recreated but needs to persist even in low
storage situations for proper functioning of your app or because
customers expect it to be available during offline use. This attribute
works on marked files regardless of what directory they are in,
including the Documents directory. These files will not be purged and
will not be included in the user's iCloud or iTunes backup. Because
these files do use on-device storage space, your app is responsible
for monitoring and purging these files periodically.