This is a pitch on Swift forums for Apple Push notification implementation.

Pitch

A lightweight, non intrusive, low dependency library to communicate with APNS over HTTP/2 built with Swift NIO.

Motivations

APNS is used to push billions of pushes a day, (7 billion per day in 2012). Many of us using Swift on the backend are using it to power our iOS applications. Having a community supported APNS implementation would go a long way to making it the fastest, free-ist, and simplest solution that exists.

Also too many non standard approaches currently exist. Some use code that depends on Security (Doesn't work on linux) and I haven't found one that uses NIO with no other dependencies. Some just execute curl commands.

Existing solutions

• https://github.com/moritzsternemann/nio-apns
• https://github.com/kaunteya/APNSwift
• https://medium.com/@nathantannar4/supporting-push-notifications-with-vapor-3-3f6cc959c789
• https://github.com/PerfectlySoft/Perfect-Notifications
• https://github.com/hjuraev/VaporNotifications

Almost all require a ton of dependencies.

Proposed Solution

Develop a Swift NIO HTTP2 solution with minimal dependencies.

A proof of concept implementation exists here

What it does do

• Provides an API for handling connection to Apples HTTP2 APNS server
• Provides proper error messages that APNS might respond with.
• Uses custom/non dependency implementations of JSON Web Token specific to APNS (using rfc7519
• Imports OpenSSL for SHA256 and ES256
• Provides an interface for signing your Push Notifications
• Signs your token request
• Sends push notifications to a specific device.
• Adheres to guidelines Apple Provides.

What it doesn't do YET

• Use an OpenSSL implementation that is not CNIOOpenSSL

What it won't do.

• Store/register device tokens
• Build an HTTP2 generic client
• Google Cloud Message
• Refresh your token no more than once every 20 minutes and no less than once every 60 minutes. (up to connection handler)
• Provide multiple device tokens to send same push to.

What it could do

• Use the SSWG HTTP2 client
• Be the APNS library for all of Server Side Swift projects!

Usage

let sslContext = try SSLContext(configuration: TLSConfiguration.forClient(applicationProtocols: ["h2"]))
let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
var verbose = true
let apnsConfig = APNSConfig.init(keyId: "9UC9ZLQ8YW", teamId: "ABBM6U9RM5", signingMode: .file(path: "/Users/kylebrowning/Downloads/key.p8"), topic: "com.grasscove.Fern", env: .sandbox)
let apns = try APNSConnection.connect(apnsConfig: apnsConfig, sslContext: sslContext, on: group.next()).wait()
if verbose {
    print("* Connected to \(apnsConfig.getUrl().host!) (\(apns.channel.remoteAddress!)")
}
let alert = Alert(title: "Hey There", subtitle: "Subtitle", body: "Body")
let aps = Aps(alert: alert, category: nil, badge: 1)
let res = try apns.send(deviceToken: "223a86bdd22598fb3a76ce12eafd590c86592484539f9b8526d0e683ad10cf4f", APNSRequest(aps: aps, custom: nil)).wait()
print("APNS response: \(res)")
try apns.close().wait()
try group.syncShutdownGracefully()
exit(0)