BlueCap provides a swift wrapper around CoreBluetooth and much more.

Features

A futures interface replacing protocol implementations.
Connection events for connect, disconnect and timeout.
Service scan timeout.
Characteristic read/write timeout.
A DSL for specification of GATT profiles.
Characteristic profile types encapsulating serialization and deserialization.
Example applications implementing Central and Peripheral roles.
A full featured extendable Central scanner and Peripheral emulator available in the App Store.
Thread safe.
Comprehensive test coverage.

Requirements

iOS 9.0+
Xcode 8.1

Installation

CocoaPods

CocoaPods is an Xcode dependency manager. It is installed with the following command,

gem install cocoapods

Requires CocoaPods 1.1+

Add BluCapKit to your to your project Podfile,

platform :ios, '9.0'
use_frameworks!

target 'Your Target Name' do
  pod 'BlueCapKit', '~> 0.2'
end

To enable DBUG output add this post_install hook to your Podfile

Carthage

Carthage is a decentralized dependency manager for Xcode projects. It can be installed using Homebrew,

brew update
brew install carthage

To add BlueCapKit to your Cartfile

github "troystribling/BlueCap" ~> 0.2

To download and build BlueCapKit.framework run the command,

carthage update

then add BlueCapKit.framework to your project.

If desired use the --no-build option,

carthage update --no-build

This will only download BlueCapKit. Then follow the steps in Manual to add it to a project.

Manual

Place the BlueCap somewhere in your project directory. You can either copy it or add it as a git submodule.
Open the BlueCap project folder and drag BlueCapKit.xcodeproj into the project navigator of your applications Xcode project.
Under your Projects Info tab set the iOS Deployment Target to 9.0 and verify that the BlueCapKit.xcodeproj iOS Deployment Target is also 9.0.
Under the General tab for your project target add the top BlueCapKit.framework as an Embedded Binary.
Under the Build Phases tab add BlueCapKit.framework as a Target Dependency and under Link Binary With Libraries add CoreLocation.framework and CoreBluetooth.framework.

Getting Started

With BlueCap it is possible to easily implement Central and Peripheral applications, serialize and deserialize messages exchanged with bluetooth devices and define reusable GATT profile definitions. The BlueCap asynchronous interface uses futures instead of the usual block interface or the protocol-delegate pattern. Futures can be chained with the result of the previous passed as input to the next. This simplifies application implementation because the persistence of state between asynchronous calls is eliminated and code will not be distributed over multiple files, which is the case for protocol-delegate, or be deeply nested, which is the case for block interfaces. In this section a brief overview of how an application is constructed will be given. Following sections will describe all use cases supported. Example applications are also available.

CentralManager

A simple CentralManager implementation that scans for Peripherals advertising a TiSensorTag Accelerometer Service, connects on peripheral discovery, discovers service and characteristics and subscribes to accelerometer data updates will be described.

All applications begin by calling CentralManager#whenStateChanges which returns a Future<Void> completed when the CBCentralManager state is set to CBCentralManagerState.PoweredOn.

let manager = CentralManager(options: [CBCentralManagerOptionRestoreIdentifierKey : "us.gnos.BlueCap.central-manager-documentation" as NSString])

let stateChangeFuture = manager.whenStateChanges()

To start scanning for Peripherals advertising the TiSensorTag Accelerometer Service follow whenStateChanges() with CentralManager#startScanning and combine the two with the SimpleFutures FutureStream#flatMap combinator. An application error object is also defined,

public enum AppError : Error {
    case invalidState
    case resetting
    case poweredOff
    case unknown
}

let serviceUUID = CBUUID(string: TISensorTag.AccelerometerService.uuid)
    
let scanFuture = stateChangeFuture.flatMap { state -> FutureStream<Peripheral> in
        switch state {
        case .poweredOn:
            return manager.startScanning(forServiceUUIDs: [serviceUUID])
        case .poweredOff:
            throw AppError.poweredOff
        case .unauthorized, .unsupported:
            throw AppError.invalidState
        case .resetting:
            throw AppError.resetting
        case .unknown:
            throw AppError.unknown
        }
}

scanFuture.onFailure { error in
    guard let appError = error as? AppError else {
        return
    }
    switch appError {
    case .invalidState:
	      break
    case .resetting:
        manager.reset()
    case .poweredOff:
        break
    case .unknown:
        break
    }
}

Here when .poweredOn is received the scan is started. On all other state changes the appropriate error is thrown and handled in the error handler.

To connect discovered peripheral the scan is followed by Peripheral#connect and combined with FutureStream#flatMap,

let connectionFuture = scanFuture.flatMap { peripheral -> FutureStream<(peripheral: Peripheral, connectionEvent: ConnectionEvent)> in
    manager.stopScanning()
    return peripheral.connect(timeoutRetries:5, disconnectRetries:5, connectionTimeout: 10.0)
}

Here the scan is also stopped after a peripheral with the desire service UUID is discovered.

The Peripheral Services and Characteristics need to be discovered and the connection events need to be handled. Service and Characteristic discovery are performed by 'Peripheral#discoverServices' and Service#discoverCharacteristics and more errors are added to AppError.

public enum AppError : Error {
    case dataCharactertisticNotFound
    case enabledCharactertisticNotFound
    case updateCharactertisticNotFound
    case serviceNotFound
    case disconnected
    case connectionFailed
    case invalidState
    case resetting
    case poweredOff
    case unknown
}

var peripheral: Peripheral?

let discoveryFuture = connectionFuture.flatMap { (peripheral, connectionEvent) -> Future<Peripheral> in
    switch connectionEvent {
    case .connect:
        return peripheral.discoverServices([serviceUUID])
    case .timeout:
        throw AppError.disconnected
    case .disconnect:
        throw AppError.disconnected
    case .forceDisconnect:
        throw AppError.connectionFailed
    case .giveUp:
        throw AppError.connectionFailed
    }
}.flatMap { discoveredPeripheral -> Future<Service> in
    guard let service = peripheral.service(serviceUUID) else {
        throw AppError.serviceNotFound
    }
    peripheral = discoveredPeripheral
    return service.discover(: [dataUUID, enabledUUID, updatePeriodUUID])
}

discoveryFuture.onFailure { error in
    guard let appError = error as? AppError else {
        return
    }
    switch appError {
    case .serviceNotFound:
        break
    case .disconnected:
        peripheral?.reconnect()
    case .connectionFailed:
        peripheral?.terminate()
    }
}

Finally read and subscribe to the data Characteristic and handle the dataCharactertisticNotFound.

public enum AppError : Error {
    case dataCharactertisticNotFound
    case enabledCharactertisticNotFound
    case updateCharactertisticNotFound
    case serviceNotFound
    case disconnected
    case connectionFailed
    case invalidState
    case resetting
    case poweredOff
    case unknown
}

let subscriptionFuture = discoveryFuture.flatMap { service -> Future<Characteristic> in
    guard let dataCharacteristic = service.characteristic(dataUUID) else {
        throw AppError.dataCharactertisticNotFound
    }
    self.accelerometerDataCharacteristic = dataCharacteristic
    return self.accelerometerEnabledCharacteristic.read(timeout: 10.0)
}.flatMap { _ -> Future<Characteristic> in
    guard let accelerometerDataCharacteristic = self.accelerometerDataCharacteristic else {
        throw AppError.dataCharactertisticNotFound
    }
    return accelerometerDataCharacteristic.startNotifying()
}.flatMap { characteristic -> FutureStream<(characteristic: Characteristic, data: Data?)> in
    return characteristic.receiveNotificationUpdates(capacity: 10)
}

dataUpdateFuture.onFailure { [unowned self] error in
    guard let appError = error as? AppError else {
        return
    }
    switch appError {
    case .dataCharactertisticNotFound:
       break
    default:
}

These examples can be written as a single flatMap chain as shown in the CentralManager Example.

PeripheralManager

A simple PeripheralManager application that emulates a TiSensorTag Accelerometer Service supporting all Characteristics will be described. It will advertise the service and respond to characteristic write requests on the writable Characteristics.

First the Characteristics and Service are created and the Characteristics are then added to Service

// create accelerometer service
let accelerometerService = MutableService(uuid: TISensorTag.AccelerometerService.uuid)

// create accelerometer data characteristic
let accelerometerDataCharacteristic = MutableCharacteristic(profile: RawArrayCharacteristicProfile<TISensorTag.AccelerometerService.Data>())
  
// create accelerometer enabled characteristic
let accelerometerEnabledCharacteristic = MutableCharacteristic(profile: RawCharacteristicProfile<TISensorTag.AccelerometerService.Enabled>())
  
// create accelerometer update period characteristic
let accelerometerUpdatePeriodCharacteristic = MutableCharacteristic(profile: RawCharacteristicProfile<TISensorTag.AccelerometerService.UpdatePeriod>())

// add characteristics to service
accelerometerService.characteristics = [accelerometerDataCharacteristic, accelerometerEnabledCharacteristic, accelerometerUpdatePeriodCharacteristic]

Next create the PeripheralManager add the Service and start advertising.

enum AppError: Error {
    case invalidState
    case resetting
    case poweredOff
    case unsupported
}

let manager = PeripheralManager(options: [CBPeripheralManagerOptionRestoreIdentifierKey : "us.gnos.BlueCap.peripheral-manager-documentation" as NSString])
    
let startAdvertiseFuture = manager.whenStateChanges().flatMap { state -> Future<Void> in
    switch state {
    case .poweredOn:
        manager.removeAllServices()
        return manager.add(self.accelerometerService)
    case .poweredOff:
        throw AppError.poweredOff
    case .unauthorized, .unknown:
        throw AppError.invalidState
    case .unsupported:
        throw AppError.unsupported
    case .resetting:
        throw AppError.resetting
    }
}.flatMap { _ -> Future<Void> in 

manager.startAdvertising(TISensorTag.AccelerometerService.name, uuids:[CBUUID(string: TISensorTag.AccelerometerService.uuid)])
}

startAdvertiseFuture.onFailure { error in
    switch error {
    case AppError.poweredOff:
        manager.reset()            
    case AppError.resetting:
        manager.reset()
    default:
	      break
    }
    manager.stopAdvertising()
}

Now respond to write events on accelerometerEnabledFuture and accelerometerUpdatePeriodFuture.

// respond to Update Period write requests
let accelerometerUpdatePeriodFuture = startAdvertiseFuture.flatMap {

accelerometerUpdatePeriodCharacteristic.startRespondingToWriteRequests()
}

accelerometerUpdatePeriodFuture.onSuccess {  (request, _) in
    guard let value = request.value, value.count > 0 && value.count <= 8 else {
        return
    }
    self.accelerometerUpdatePeriodCharacteristic.value = value
    self.accelerometerUpdatePeriodCharacteristic.respondToRequest(request, withResult:CBATTError.success)
}

// respond to Enabled write requests
let accelerometerEnabledFuture = startAdvertiseFuture.flatMap {
    accelerometerEnabledCharacteristic.startRespondingToWriteRequests(capacity: 2)
}

accelerometerEnabledFuture.onSuccess { (request, _) in
    guard let value = request.value, value.count == 1 else {
        return
    }
    self.accelerometerEnabledCharacteristic.value = request.value
    self.accelerometerEnabledCharacteristic.respondToRequest(request, withResult:CBATTError.success)
}

See PeripheralManager Example for details.

Test Cases

Test Cases are available. To run type,

pod install

and run from test tab in generated workspace.

Examples

Examples are available that implement both CentralManager and PeripheralManager. The BluCap app is also available. The example projects are constructed using either CocoaPods or Carthage. The CocaPods projects require installing the Pod before building,

pod install

and Carthage projects require,

carthage update

BlueCap	BlueCap provides CentralManager, PeripheralManager and iBeacon Ranging with implementations of GATT profiles. In CentralManager mode a scanner for Bluetooth LE peripherals is provided. In PeripheralManager mode an emulation of any of the included GATT profiles or an iBeacon is supported. In iBeacon Ranging mode beacon regions can be configured and monitored.
CentralManager	CentralManager implements a BLE CentralManager scanning for services advertising the TiSensorTag Accelerometer Service. When a Peripheral is discovered a connection is established, services are discovered, the accelerometer is enabled and the application subscribes to accelerometer data updates. It is also possible to change the data update period.
CentralManagerWithProfile	A version of CentralManager that uses GATT Profile Definitions to create services.
PeripheralManager	PeripheralManager implements a BLE PeripheralManager advertising a TiSensorTag Accelerometer Service. PeripheralManager uses the onboard accelerometer to provide data updates.
PeripheralManagerWithProfile	A version of Peripheral that uses GATT Profile Definitions to create services.
Beacon	Peripheral emulating an iBeacon.

Documentation

BlueCap supports many features that simplify writing Bluetooth LE applications. Use cases with example implementations are described in each of the following sections.

CentralManager: The BlueCap CentralManager implementation replaces CBCentralManagerDelegate and CBPeripheralDelegate protocol implementations with a Scala Futures interface using SimpleFutures.
PeripheralManager: The BlueCap PeripheralManager implementation replaces CBPeripheralManagerDelegate protocol implementations with a Scala Futures interface using SimpleFutures.
Serialization/Deserialization: Serialization and deserialization of device messages.
GATT Profile Definition: Define reusable GATT profiles and add profiles to the BlueCap app.

Jing-Li/BlueCap