Swift – macOS `batteryLevel` property

Question

In iOS there's a simple approach to get a level of iPhone battery:

UIDevice.current.batteryLevel

What's a macOS batteryLevel equivalent for MacBooks?

Answer 1

Getting the battery level in macOS is not as easy as in iOS, but it is still pretty easy. You have to use the IOKit framework for this. You can use this code to read almost all of the important information from the internal battery.

InternalBattery.swift

import Foundation
import IOKit.ps

public class InternalBattery {
    public var name: String?

    public var timeToFull: Int?
    public var timeToEmpty: Int?

    public var manufacturer: String?
    public var manufactureDate: Date?

    public var currentCapacity: Int?
    public var maxCapacity: Int?
    public var designCapacity: Int?

    public var cycleCount: Int?
    public var designCycleCount: Int?

    public var acPowered: Bool?
    public var isCharging: Bool?
    public var isCharged: Bool?
    public var amperage: Int?
    public var voltage: Double?
    public var watts: Double?
    public var temperature: Double?

    public var charge: Double? {
        get {
            if let current = self.currentCapacity,
               let max = self.maxCapacity {
                return (Double(current) / Double(max)) * 100.0
            }

            return nil
        }
    }

    public var health: Double? {
        get {
            if let design = self.designCapacity,
               let current = self.maxCapacity {
                return (Double(current) / Double(design)) * 100.0
            }

            return nil
        }
    }

    public var timeLeft: String {
        get {
            if let isCharging = self.isCharging {
                if let minutes = isCharging ? self.timeToFull : self.timeToEmpty {
                    if minutes <= 0 {
                        return "-"
                    }

                    return String(format: "%.2d:%.2d", minutes / 60, minutes % 60)
                }
            }

            return "-"
        }
    }

    public var timeRemaining: Int? {
        get {
            if let isCharging = self.isCharging {
                return isCharging ? self.timeToFull : self.timeToEmpty
            }

            return nil
        }
    }
}

InternalFinder.swift:

import Foundation
import IOKit.ps

public class InternalFinder {
    private var serviceInternal: io_connect_t = 0 // io_object_t
    private var internalChecked: Bool = false
    private var hasInternalBattery: Bool = false

    public init() { }

    public var batteryPresent: Bool {
        get {
            if !self.internalChecked {
                let snapshot = IOPSCopyPowerSourcesInfo().takeRetainedValue()
                let sources = IOPSCopyPowerSourcesList(snapshot).takeRetainedValue() as Array

                self.hasInternalBattery = sources.count > 0
                self.internalChecked = true
            }

            return self.hasInternalBattery
        }
    }

    fileprivate func open() {
        self.serviceInternal = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("AppleSmartBattery"))
    }

    fileprivate func close() {
        IOServiceClose(self.serviceInternal)
        IOObjectRelease(self.serviceInternal)

        self.serviceInternal = 0
    }

    public func getInternalBattery() -> InternalBattery? {
        self.open()

        if self.serviceInternal == 0 {
            return nil
        }

        let battery = self.getBatteryData()

        self.close()

        return battery
    }

    fileprivate func getBatteryData() -> InternalBattery {
        let battery = InternalBattery()

        let snapshot = IOPSCopyPowerSourcesInfo().takeRetainedValue()
        let sources = IOPSCopyPowerSourcesList(snapshot).takeRetainedValue() as Array

        for ps in sources {
            // Fetch the information for a given power source out of our snapshot
            let info = IOPSGetPowerSourceDescription(snapshot, ps).takeUnretainedValue() as! Dictionary<String, Any>

            // Pull out the name and capacity
            battery.name = info[kIOPSNameKey] as? String

            battery.timeToEmpty = info[kIOPSTimeToEmptyKey] as? Int
            battery.timeToFull = info[kIOPSTimeToFullChargeKey] as? Int
        }

        // Capacities
        battery.currentCapacity = self.getIntValue("CurrentCapacity" as CFString)
        battery.maxCapacity = self.getIntValue("MaxCapacity" as CFString)
        battery.designCapacity = self.getIntValue("DesignCapacity" as CFString)

        // Battery Cycles
        battery.cycleCount = self.getIntValue("CycleCount" as CFString)
        battery.designCycleCount = self.getIntValue("DesignCycleCount9C" as CFString)

        // Plug
        battery.acPowered = self.getBoolValue("ExternalConnected" as CFString)
        battery.isCharging = self.getBoolValue("IsCharging" as CFString)
        battery.isCharged = self.getBoolValue("FullyCharged" as CFString)

        // Power
        battery.amperage = self.getIntValue("Amperage" as CFString)
        battery.voltage = self.getVoltage()

        // Various
        battery.temperature = self.getTemperature()

        // Manufaction
        battery.manufacturer = self.getStringValue("Manufacturer" as CFString)
        battery.manufactureDate = self.getManufactureDate()

        if let amperage = battery.amperage,
           let volts = battery.voltage, let isCharging = battery.isCharging {
            let factor: CGFloat = isCharging ? 1 : -1
            let watts: CGFloat = (CGFloat(amperage) * CGFloat(volts)) / 1000.0 * factor

            battery.watts = Double(watts)
        }

        return battery
    }

    fileprivate func getIntValue(_ identifier: CFString) -> Int? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, identifier, kCFAllocatorDefault, 0) {
            return value.takeRetainedValue() as? Int
        }

        return nil
    }

    fileprivate func getStringValue(_ identifier: CFString) -> String? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, identifier, kCFAllocatorDefault, 0) {
            return value.takeRetainedValue() as? String
        }

        return nil
    }

    fileprivate func getBoolValue(_ forIdentifier: CFString) -> Bool? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, forIdentifier, kCFAllocatorDefault, 0) {
            return value.takeRetainedValue() as? Bool
        }

        return nil
    }

    fileprivate func getTemperature() -> Double? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, "Temperature" as CFString, kCFAllocatorDefault, 0) {
            return value.takeRetainedValue() as! Double / 100.0
        }

        return nil
    }

    fileprivate func getDoubleValue(_ identifier: CFString) -> Double? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, identifier, kCFAllocatorDefault, 0) {
            return value.takeRetainedValue() as? Double
        }

        return nil
    }

    fileprivate func getVoltage() -> Double? {
        if let value = getDoubleValue("Voltage" as CFString) {
            return value / 1000.0
        }

        return nil
    }

    fileprivate func getManufactureDate() -> Date? {
        if let value = IORegistryEntryCreateCFProperty(self.serviceInternal, "ManufactureDate" as CFString, kCFAllocatorDefault, 0) {
            let date = value.takeRetainedValue() as! Int

            let day = date & 31
            let month = (date >> 5) & 15
            let year = ((date >> 9) & 127) + 1980

            var components = DateComponents()
            components.calendar = Calendar.current
            components.day = day
            components.month = month
            components.year = year

            return components.date
        }

        return nil
    }
}

Usage:

let internalFinder = InternalFinder()
if let internalBattery = internalFinder.getInternalBattery() {
    // Internal battery found, access properties here.
}