How to programmatically check support of 'Face

Question

I've integrated LocalAuthentication for my app security purpose, which has been supporting 'Touch Id' based supporting. But now, apple has recently added 'Face Id' based authentication also.

How can I check, which type of authentication is supported by a device. Touch Id or Face Id?

Answer 1

I made a singleton class for local authentication as it helps to initialise an instance one time using static property for the entire application.

import Foundation
import LocalAuthentication

public class LocalAuthManager: NSObject {

    public static let shared = LocalAuthManager()
    private let context = LAContext()
    private let reason = "Your Request Message"
    private var error: NSError?

    enum BiometricType: String {
        case none
        case touchID
        case faceID
    }

    private override init() {

    }

    // check type of local authentication device currently support
    var biometricType: BiometricType {
        guard self.context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) else {
            return .none
        }

        if #available(iOS 11.0, *) {
            switch context.biometryType {
            case .none:
                return .none
            case .touchID:
                return .touchID
            case .faceID:
                return .faceID
            }
        } else {
            return self.context.canEvaluatePolicy(.deviceOwnerAuthentication, error: nil) ? .touchID : .none
        }
    }
}

Implementation:

func checkAuth() {
     let authType = LocalAuthManager.shared.biometricType
        switch authType {
        case .none:
            print("Device not registered with TouchID/FaceID")
        case .touchID:
            print("Device support TouchID")
        case .faceID:
            print("Device support FaceID")
        }
 }

Answer 2

From @Markicevic extension, but ignoring cases where user is not enrolled, etc...

extension LAContext {

enum BiometricType: String {
    case none = ""
    case touchID = "Touch ID"
    case faceID = "Face ID"
}

static var biometricType: BiometricType {
    var error: NSError?

    let context = LAContext()

    _ = context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error)

    if error?.code == LAError.Code.touchIDNotAvailable.rawValue {
        return .none
    }

    if #available(iOS 11.0, *) {
        switch context.biometryType {
        case .none:
            return .none
        case .touchID:
            return .touchID
        case .faceID:
            return .faceID
        }
    } else {
        return  context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: nil) ? .touchID : .none
    }
}

}

Answer 3

Objective C :)

/** Only interesting devices are enumerated here. To change view constraints depending
 on screen height. Or the top notch for iPhone X
 */
typedef NS_ENUM(NSUInteger, BPDeviceType) {
    BPDeviceTypeUnknown,
    BPDeviceTypeiPhone4,
    BPDeviceTypeiPhone5,
    BPDeviceTypeiPhone6,
    BPDeviceTypeiPhone6Plus,
    BPDeviceTypeiPhone7,
    BPDeviceTypeiPhone7Plus,
    BPDeviceTypeiPhoneX,
    BPDeviceTypeiPad
};

+ (BPDeviceType)getDeviceType {
    double screenHeight = [[UIScreen mainScreen] bounds].size.height;
    if(UI_USER_INTERFACE_IDIOM()==UIUserInterfaceIdiomPad)
    {
        return BPDeviceTypeiPad;

    } else if (UI_USER_INTERFACE_IDIOM()== UIUserInterfaceIdiomPhone)
    {
        if (@available(iOS 11, *)) {
            UIEdgeInsets insets = [UIApplication sharedApplication].delegate.window.safeAreaInsets;
            if (insets.top > 0) {
                return BPDeviceTypeiPhoneX;
            }
        }

        if(screenHeight == 480) {
            return BPDeviceTypeiPhone4;
        } else if (screenHeight == 568) {
            return BPDeviceTypeiPhone5;
        } else if (screenHeight == 667) {
            return BPDeviceTypeiPhone6;
        } else if (screenHeight == 736) {
            return BPDeviceTypeiPhone6Plus;
        }
    }
    return BPDeviceTypeUnknown;
}

+ (BOOL) isBiometricIDAvailable {
    if (![LAContext class]) return NO;

    LAContext *myContext = [[LAContext alloc] init];
    NSError *authError = nil;
    if (![myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
        NSLog(@"%@", [authError localizedDescription]);
        return NO;
    }
    return YES;
}

+ (BOOL) isTouchIDAvailable {
    if (![LAContext class]) return NO;

    LAContext *myContext = [[LAContext alloc] init];
    NSError *authError = nil;
    if (![myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
        NSLog(@"%@", [authError localizedDescription]);
        return NO;
        // if (authError.code == LAErrorTouchIDNotAvailable) {}
    }

    if (@available(iOS 11.0, *)) {
        if (myContext.biometryType == LABiometryTypeTouchID){
            return YES;
        } else {
            return NO;
        }
    } else {
        return YES;
    }
}

+ (BOOL) supportFaceID {
    return [BPDeviceInfo getDeviceType] == BPDeviceTypeiPhoneX;
}

+ (BOOL) isFaceIDAvailable {
    if (![LAContext class]) return NO;

    LAContext *myContext = [[LAContext alloc] init];
    NSError *authError = nil;
    if (![myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
        NSLog(@"%@", [authError localizedDescription]);
        return NO;
    }

    if (@available(iOS 11.0, *)) {
        if (myContext.biometryType == LABiometryTypeFaceID){
            return YES;
        } else {
            return NO;
        }
    } else {
        return NO;
    }
}

Answer 4

Face ID is available from iOS 11 and iPhone X comes with iOS 11 by default. In the LocalAuth framework they have added a 'biometryType' property which can give you ability to detect whether Face ID is available on device.

/// checks if face id is avaiable on device
func faceIDAvailable() -> Bool {
    if #available(iOS 11.0, *) {
        let context = LAContext()
        return (context.canEvaluatePolicy(LAPolicy.deviceOwnerAuthentication, error: nil) && context.biometryType == .faceID)
    }
    return false
}