About

CloudUserDefaults automatically syncs UserDefaults values that use a key with a specified prefix to the cloud. Silently listening to system events it detects when a UserDefaults key with a given prefix is changed and automatically syncs the value. For example, if you choose cloud_ as the prefix UserDefaults.standard.set(1, forKey: "cloud_count") is set on all the user’s devices.

This is based on Mugunth Kumar’s elegant solution MKiCloudSync an Objective-C GitHub repository that is now archived. Thanks to Paul Hudson for the introduction to MKiCloudSync.

Installation

Swift Package Manager

If you are using Xcode 11 or later:

1. Click File
2. Swift Packages
3. Add Package Dependency...
4. Specify the git URL for CloudUserDefaults.

https://github.com/nbasham/CloudUserDefaults.git

Manual

Copy CloudUserDefaults.swift to your project

Setup

In Xcode, click your project, click your target, click Signing & Capabilities, click + Capability, select iCloud. Check the Key-value storage checkbox.

NOTE iCloud events are not sent to the simulator.

Usage

Create an instance of CloudUserDefaults some place it will stay in scope (e.g. in your AppDelegate) and call start with a prefix of your choosing e.g.

import CloudUserDefaults
...
let cloudUserDefaults = CloudUserDefaults()
cloudUserDefaults.start(prefix: "cloud_")

That’s it, whenever a UserDefaults key starts with cloud_ it is automatically synced to all the user’s devices e.g.

UserDefaults.standard.set(42, forKey: "cloud_answer") // synced to cloud
UserDefaults.standard.set(42, forKey: "answer")       // local

Subscribe to CloudUserDefaults.cloudSyncNotification if you want to be notified when user defaults from another device are delivered e.g.

NotificationCenter.default.addObserver(self,
 selector: #selector(cloudUpdate(notification:)),
 name: CloudUserDefaults.cloudSyncNotification,
 object: nil)

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT