BiometryTypeBugWorkaround

LAContext of LocalAuthentication framework has a property called biometryType. It has a type of biometric authentication supported by the device. It’s supporsed to be set after called LAContext‘s canEvaluatePolicy(_:error:). But in some cases, it isn’t set. It’s a bug of iOS 11.0.x.

Futhermore, iOS devices would be crash if you call biometryType on iOS 11.0.

(See more details of bugs: http://www.openradar.me/radar?id=5061720007507968)

This library provides a workaround for these bugs.

Usage

This library provides just 1 method as LAContext‘s extension. It’s biometryTypeForWorkaround(with:). It’s a replacement of LAContext‘s biometryType property. You can use it like this:

let context = LAContext()
var error: NSError?
let canEvaluate = context.canEvaluatePolicy(
    .deviceOwnerAuthenticationWithBiometrics,
    error: &error)

let biometryType = context.biometryTypeForWorkaround(
    with: error as? LAError)

Caution

• Don’t call this method before calling canEvaluatePolicy(_:error:). It doesn’t have the default value (none).
• This library is unnecessary if your app’s deployment target is iOS 11.1 or later. Because this library is for the bug of 11.0 and 11.0.x.

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Installation

BiometryTypeBugWorkaround is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'BiometryTypeBugWorkaround'

Author

Manabu Nakazawa (@mshibanami)

License

BiometryTypeBugWorkaround is available under the MIT license. See the LICENSE file for more info.