A small library that adds concurrency to CoreBluetooth APIs.
- Async/Await APIs
- Queueing of commands
- Data conversion to common types
- Thread safety
- Convenience APIs for reading/writing without needing to explicitly discover characteristics.
- Convenience API for waiting until Bluetooth is ready.
Start scanning by calling the central manager's scanForPeripherals
function. It returns an AsyncStream you can use to iterate over the
discovered peripherals. Once you're satisfied with your scan, you can
break from the loop and stop scanning.
let centralManager = CentralManager()
try await centralManager.waitUntilReady()
let scanDataStream = try await centralManager.scanForPeripherals(withServices: nil)
for await scanData in scanDataStream {
// Check scan data...
}
await centralManager.stopScan()Once you have your peripheral, you can use the central manager to connect to it. Note you must hold a reference to the Peripheral while it's connected.
try await centralManager.connect(peripheral, options: nil)The central manager publishes several events. You can subscribe to them by using the eventPublisher.
centralManager.eventPublisher
.sink {
switch $0 {
case .didConnectPeripheral(let peripheral):
print("Connected to \(peripheral.identifier)")
default:
break
}
}
.store(in: &cancellables)See CentralManagerEvent to see available events.
You can use convenience functions for reading characteristics. They will find the characteristic by using a UUID, and
parse the data into the appropriate type.
let value: String? = try await peripheral.readValue(
forCharacteristicWithUUID: UUID(uuidString: "")!,
ofServiceWithUUID: UUID(uuidString: "")!
)Similar to reading, we have convenience functions for writing to characteristics.
try await peripheral.writeValue(
value,
forCharacteristicWithUUID: UUID(uuidString: "")!,
ofServiceWithUUID: UUID(uuidString: "")!
)To get notified when a characteristic's value is updated, we provide a publisher you can subscribe to:
let characteristicUUID = CBUUID()
peripheral.characteristicValueUpdatedPublisher
.filter { $0.uuid == characteristicUUID }
.map { try? $0.parsedValue() as String? } // replace `String?` with your type
.sink { value in
print("Value updated to '\(value)'")
}
.store(in: &cancellables)Remember that you should enable notifications on that characteristc to receive updated values.
try await peripheral.setNotifyValue(true, characteristicUUID, serviceUUID)To cancel a specific operation, you can wrap your call in a Task:
let fetchTask = Task {
do {
return try await peripheral.readValue(
forCharacteristicWithUUID: UUID(uuidString: "")!,
ofServiceWithUUID: UUID(uuidString: "")!
)
} catch {
return ""
}
}
fetchTask.cancel()There might also be cases were you want to stop awaiting for all responses. For example, when bluetooth has been powered off. This can be done like so:
centralManager.eventPublisher
.sink {
switch $0 {
case .didUpdateState(let state):
guard state == .poweredOff else {
return
}
centralManager.cancelAllOperations()
peripheral.cancelAllOperations()
default:
break
}
}
.store(in: &cancellables)You can find practical, tasty recipes for how to use AsyncBluetooth in the
AsyncBluetooth Cookbook.
This library can be installed using the Swift Package Manager by adding it to your Package Dependencies.
- iOS 14.0+
- MacOS 11.0+
- Swift 5
- Xcoce 13.2.1+
Licensed under MIT license.