AppTransaction: how to use in ObjC apps (now that we are forced to use it after the exit(173) deprecation)

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starbird1975 OP

Created Sep ’24

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Hello

We are developers of a long-running game series and now reports have started to come in that users who install any of our previous games from the Mac App Store on OS X Sequoia are shown a popup claiming "The exit(173) API is no longer available". It's actually a lie, the mechanism is still there, the receipt generation still works and the game still runs afterwards. But the popup is confusing to users therefore we need to update the code.

Apparently the replacement for the old receipt generation mechanism is AppTransaction which does not exist for Objective C. We have attempted to use it using the Swift/ObjC interoperability and failed so far. The problem is that we need to call async methods in AppTransaction and all our attempts to make this work have failed so far. It seems as the actor/@MainActor concept is not supported by Swift/ObjC interoperability and without those concepts we don't know how to pass results from the async context to the callers from ObjC.

The lack of usable information and code online regarding this topic is highly frustrating. Apple really needs to provide better support for developers if they want us to continue to support the Mac platform with high quality games and applications on the Mac App Store.

We would appreciate if anyone can cook up a working sample code how to use AppTransaction in ObjC. Thanks in advance!

Answered by DTS Engineer in 810009022

All I need to do is execute one line of Swift:

Now that’s something I can help with. Here how I did this:

I created a new project from an Objective-C template.
I choose File > New > File from Template and then chose the macOS > Cocoa Class template, with Swift as the language.
This asked whether I want to create a bridging header. I allowed that, but it’s not relevant to this discussion.

I edited the file to look like this:

import StoreKit

@objc
class MyAppTransaction: NSObject {

    @objc
    class func checkReceipt() async -> String {
        do {
            let verificationResult = try await AppTransaction.shared
            switch verificationResult {
            case .unverified(_, _):
                return "NG"
            case .verified(_):
                return "OK"
            }
        } catch {
            return "ERR"
        }
    }
}

I’ve chosen silly status values. You can tweak these values, or even the types, as you wish. However, the types must be Objective-C representable. In this case I’m using String, which bridges to NSString.

On the Objective-C side, I added this:

#import "Test764537-Swift.h"

and then called the Swift code like this:

[MyAppTransaction checkReceiptWithCompletionHandler:^(NSString * _Nonnull status) {
    NSLog(@"status: %@", status);
}];

I’m working with Xcode 16.0, but I don’t think there’s anything Xcode 16 specific about this.

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Answer 1

Tlaloc OP

2w

Thank you so much for your help. I haven't decided what version to target, but this is easy. The fact that my project has a valid receipt that I got by calling exit(173) made it easier. In my opinion deprecating this is a bad idea that will make it harder for developers.

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