NSAttributedString in Core Data (iOS 14)

Question

Created Jul ’20

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I had an app built using SwiftUI and used to work without any issues, but when I build it for iOS 14 the app became very slow and the console began showing this message:

'NSKeyedUnarchiveFromData' should not be used to for un-archiving and will be removed in a future release

After investigating, I concluded that using NSAttributedString in Core Data as Transformable object is the reason.

Does anyone has a better way for storing NSAttributedString in Core Data for iOS 14 ?

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Answer 1

OOPer OP

Jul ’20

How have you defined the Transformer?

0

Answer 2

alsarraf OP

Jul ’20

@OOPer I wanted to upload a picture for the attribute information, but I didn't find a way to do so in the forum.
Anyway, you can find its information below:

Attribute Name: content
"Type": Transformable
NON-OPTIONAL
NON-TRANSIENT
NON-DERIVED
"Transformer": EMPTY
"Custom Class": NSAttributedString
"Module": EMPTY

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Answer 3

OOPer OP

Jul ’20

Thanks for showing the definition.

Have you tried setting NSSecureUnarchiveFromDataTransformer to "Transformer"?

1

Answer 4

alsarraf OP

Jul ’20

@OOPer I have just tried what you said. The app crashed with the following error:

>>> Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Object of class NSConcreteMutableAttributedString is not among allowed top level class list (
NSArray,
NSDictionary,
NSSet,
NSString,
NSNumber,
NSDate,
NSData,
NSURL,
NSUUID,
NSNull
)'

0

Answer 5

OOPer OP

Jul ’20

Thanks for testing. Seems you may need to define your own custom Transformer for NSAttributedString (without using NSKeyedUnarchiveFromData or similar) by yourself.

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Answer 6

OOPer OP

Jul ’20

As far as I tried in a simple sample project, this Transformer worked.

Code Block import UIKit
import CoreData
@objc(NSAttributedStringTransformer)
class NSAttributedStringTransformer: NSSecureUnarchiveFromDataTransformer {
		override class var allowedTopLevelClasses: [AnyClass] {
				return super.allowedTopLevelClasses + [NSAttributedString.self]
		}
}

4

Answer 7

alsarraf OP

Aug ’20

I have ended up using a separate entity for each attribute (color, alignment, etc) and the application is working now as expected.

Thank you @OOPer for your help.

0