Comlink

Comlink allows you to send objects between the main app and the extension (i.e. Watch Extension). Comlink persists via NSKeyedArchiver the object that needs to be sent and then posts a Darwin Notification. The notification will be catched by Comlink which will unarchive the object and deliver it to its listeners. Please note that the objects passed must conform to the NSCoding.

Background

A comlink was a portable device that transferred voice signals from one location to another (http://starwars.wikia.com/wiki/Comlink).

Requirements

• iOS 7.0+ / Mac OS X 10.9+
• Xcode 7
• Swift 2.0

If you want to use this framework with Swift 1.2 check out version 0.1.

Installation

Embedded frameworks require a minimum deployment target of iOS 8 or OS X Mavericks. To use Comlink with a project targeting iOS 7, you must include all the Source files directly in your project and add COMNotificationHelper.h to your bridging header. To use Comlink your app and its extensions must support shared app groups.

Usage

Send objects

comlinkSender = ComlinkSender(applicationGroupIdentifier: "application.group.identifier", directoryName: "directory name")
comlinkSender.sendObject(object, identifier: "identifier") // object must conform to the NSCoding protocol

Receive objects

comlinkReceiver = ComlinkReceiver(applicationGroupIdentifier: "application.group.identifier", directoryName: "directory name")
comlinkReceiver.addListener(self, identifier: "identifier")

...

func objectChanged(object: AnyObject) {
	let obj = comlinkReceiver.retrieveObject("identifier")
	// do something with obj
}

Sending and receiving images

To send an image, save it in the shared folder and then send a notification containing the path.

let path = // use containerURLForSecurityApplicationGroupIdentifier to create the path 
UIImageJPEGRepresentation(image, 100).writeToFile(path, atomically: true)
comlinkSender.sendObject(path, identifier: "image available")

To load the image:

func objectChanged(object: AnyObject) {
	let path = comlinkReceiver.retrieveObject("identifier") as! String
	let maybeData = NSData(contentsOfFile: path)
	if let data = maybeData {
		image = UIImage(data: data)
	}
}