Capture iBeacon packets and show them in Touch Bar

beaconcapture.swift

#!/usr/bin/swift
import CoreBluetooth
import AppKit

class AppDelegate: NSResponder, CBCentralManagerDelegate, NSTouchBarDelegate, NSApplicationDelegate {
    let manager: CBCentralManager
    var advertises: [Advertise] = []

    override init() {
        manager = CBCentralManager(delegate: nil, queue: DispatchQueue.main)
        super.init()
        manager.delegate = self
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    struct Advertise: CustomStringConvertible {
        enum ManufacturerData {
            case iBeacon(UUID, UInt16, UInt16) // uuid, major, minor
            case apple(UInt8, UInt8, Data) // Type, Subtype, remainder
            case other(Data)
        }
        var manufacturerData: ManufacturerData
        var name: String?
        var time: Date

        var description: String {
            let df = DateFormatter()
            df.locale = Locale.current
            df.dateStyle = .short
            df.timeStyle = .medium
            let timeString = df.string(from: time)
            switch manufacturerData {
            case let .iBeacon(uuid, major, minor):
                return "\(timeString) iBeacon(\(name ?? "unknown")) (\(uuid.uuidString), \(major), \(minor))"
            case let .apple(type, subtype, data):
                return "\(timeString) apple(type=\((type, subtype)))(\(name ?? "unknown")) (\((data as NSData).description))"
            case let .other(data):
                return "\(timeString) other(\(name ?? "unknown")) (\((data as NSData).description))"
            }
        }
    }

    public func centralManagerDidUpdateState(_ central: CBCentralManager) {
        NSLog("%@", "\(#function): \(central.state.rawValue)")
        guard central.state == .poweredOn else { return }
        manager.scanForPeripherals(withServices: nil, options: [CBCentralManagerScanOptionAllowDuplicatesKey: true])
    }

    func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        guard let manufacturerData = advertisementData["kCBAdvDataManufacturerData"] as? Data else { return } // ignore non iBeacon
        let adData: Advertise.ManufacturerData
        if manufacturerData.starts(with: [0x4c, 0x00, 0x02, 0x15]) && manufacturerData.count == 4 + 16 + 2 + 2 + 1 {
            let (uuid, major, minor) = manufacturerData.withUnsafeBytes { p in
                (NSUUID(uuidBytes: p + 4) as UUID,
                 CFSwapInt16BigToHost((p + 20).withMemoryRebound(to: UInt16.self, capacity: 1) {$0.pointee}),
                 CFSwapInt16BigToHost((p + 22).withMemoryRebound(to: UInt16.self, capacity: 1) {$0.pointee}))
            }
            adData = .iBeacon(uuid, major, minor)
        } else if manufacturerData.starts(with: [0x4c, 0x00]) {
            let (type, subtype) = manufacturerData.withUnsafeBytes { (p: UnsafePointer<UInt8>) in
                ((p + 2).pointee, (p + 3).pointee)
            }
            adData = .apple(type, subtype, Data(manufacturerData.dropFirst(4)))
        } else {
            adData = .other(manufacturerData)
        }
        let advertise = Advertise(manufacturerData: adData, name: peripheral.name, time: Date())
        print("\(advertise)")
        fflush(__stdoutp)

        if #available(OSX 10.12, *), case .iBeacon = advertise.manufacturerData {
            touchbarLabel.stringValue = advertise.description
        }
    }

    @available(OSX 10.12.2, *)
    lazy var touchbar: NSTouchBar = {
        let tb = NSTouchBar()
        tb.delegate = self
        tb.defaultItemIdentifiers = [NSTouchBarItem.Identifier(rawValue: "hoge")]
        return tb
    }()

    @available(OSX 10.12.2, *)
    override func makeTouchBar() -> NSTouchBar? {
        return touchbar
    }

    @available(OSX 10.12, *)
    lazy var touchbarLabel: NSTextField = NSTextField(labelWithString: "")

    @available(OSX 10.12.2, *)
    func touchBar(_ touchBar: NSTouchBar, makeItemForIdentifier identifier: NSTouchBarItem.Identifier) -> NSTouchBarItem? {
        let item = NSCustomTouchBarItem(identifier: identifier)
        item.view = touchbarLabel
        return item
    }
}

let appDelegate = AppDelegate()
let app = NSApplication.shared
app.setActivationPolicy(.regular)
app.delegate = appDelegate
app.run()