WFNotificationCenter

WFDistributedNotificationCenter is a notification center for communicating between your app and your extensions.

Features

• Works between any process in the same application group
• API compatible with NSNotificationCenter
• Supports notifications with rich userInfo dictionaries
• Handles process suspension gracefully (and delivers notifications upon resume)

Usage

WFDistributedNotificationCenter *center = [[WFDistributedNotificationCenter alloc] initWithSecurityApplicationGroupIdentifier:@"group.test"];

[center postNotificationName:@"UpdatedStuff" object:nil userInfo:@{@"ChangedIds": @[@3,@4,@10]}];

Installation

Manually

Add WFDistributedNotificationCenter.h and WFDistributedNotificationCenter.m into your project.

Architecture

The traditional model for distributed notifications is client-server, where applications are the clients and a daemon (distnoted, notifyd, etc) acts as the server. The server receives notifications from its clients and distributes them appropriately

This model doesn't work on iOS. There isn't a daemon that supports posting rich notifications, and you can't write your own. With WFDistributedNotificationCenter, the connections are decentralized. When applications want to listen for a notification, they create a local mach server and update a shared registry with the mach port name. Clients posting notifications read this registry and send notifications to the appropriate process. This communication happens using the public CFMessagePort API, and the shared registry is currently stored in the app group container.

Notes

• It is not meant to be used between two separate apps yet, only between an app and its extensions (it is not designed to be runtime compatible across versions)
• It allows sending any object in the userInfo dictionary that adheres to NSSecureCoding, provided that the observer specifies the class in allowedClasses
• Test coverage is incomplete, but being worked on

License

WFNotificationCenter is available under the MIT license. See the LICENSE file for more info.