Mobile Kotlin biometry

This is a Kotlin Multiplatform library that provides authentication by FaceId and TouchId(Fingerprint)

Table of Contents

• Features
• Requirements
• Installation
• Usage
• Samples
• Set Up Locally
• Contributing
• License

Features

• Biometric user authentication - allows you to use familiar user authentication methods from business logic
• Compose Multiplatform support (partly, mobile platforms: Android, iOS)

Requirements

• Gradle version 6.8+
• Android API 16+
• iOS version 11.0+

Installation

root build.gradle

allprojects {
    repositories {
        mavenCentral()
    }
}

project build.gradle

dependencies {
    commonMainApi("dev.icerock.moko:biometry:0.4.0")

    // Compose Multiplatform
    commonMainApi("dev.icerock.moko:biometry-compose:0.4.0")

    // Jetpack Compose (only for android, if you don't use multiplatform)
    implementation("dev.icerock.moko:biometry-compose:0.4.0")
}

Usage

common

In commonMain we should create ViewModel like:

class SampleViewModel(
    val biometryAuthenticator: BiometryAuthenticator
) : ViewModel() {

    fun tryToAuth() = viewModelScope.launch {
        try {
            val isSuccess = biometryAuthenticator.checkBiometryAuthentication(
                requestTitle = "Biometry".desc(),
                requestReason = "Just for test".desc(),
                failureButtonText = "Oops".desc(),
                allowDeviceCredentials = false // true - if biometric permission is not granted user can authorise by device creds
            )

            if (isSuccess) {
                // Do something onSuccess
            }
        } catch (throwable: Throwable) {
            // Do something onFailed
        }
    }
}

After create ViewModel, let's integrate on platform.

Android

class MainActivity : AppCompatActivity() {

    private lateinit var viewModel: SampleViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Create viewModel from common code.
        viewModel = getViewModel {
            SampleViewModel(
                // Pass platform implementation of the Biometry Authenticator
                // to a common code
                biometryAuthenticator = BiometryAuthenticator(
                    applicationContext = applicationContext
                )
            )
        }

        // Binds the Biometry Authenticator to the view lifecycle
        viewModel.biometryAuthenticator.bind(
            lifecycle = this@MainActivity.lifecycle,
            fragmentManager = supportFragmentManager
        )
    }
}

Compose:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        setContent {
            val biometryFactory: BiometryAuthenticatorFactory = rememberBiometryAuthenticatorFactory()

            // Create viewModel from common code
            val viewModel = getViewModel {
                SampleViewModel(
                    // Pass platform implementation of the Biometry Authenticator
                    // to a common code
                    biometryAuthenticator = biometryFactory.createBiometryAuthenticator()
                )
            }

            // Binds the Biometry Authenticator to the view lifecycle
            BindBiometryAuthenticatorEffect(viewModel.biometryAuthenticator)

            // Same screen content here
        }
    }
}

iOS:

class SampleViewController: UIViewController {
    
    private var viewModel: SampleViewModel!
        
    override func viewDidLoad() {
        super.viewDidLoad()

        self.viewModel = SampleViewModel(
            biometryAuthenticator: BiometryBiometryAuthenticator(),
        )
    }
    
    @IBAction private func loginAction() {
        self.viewModel.tryToAuth()
    }
}

Additionally, you need add NSFaceIDUsageDescription key in Info.plist of your project:

<key>NSFaceIDUsageDescription</key>
<string>$(PRODUCT_NAME) Authentication with TouchId or FaceID</string>

Compose Multiplatform:

@Composable
fun BiometryScreen() {
    val biometryFactory: BiometryAuthenticatorFactory = rememberBiometryAuthenticatorFactory()
    
    BiometryScreen(
        viewModel = getViewModel(
            key = "biometry-screen",
            factory = viewModelFactory {
                BiometryViewModel(
                    biometryAuthenticator = biometryAuthenticatorFactory.createBiometryAuthenticator()
                )
            }
        )
    )
}

@Composable
private fun BiometryScreen(
    viewModel: BiometryViewModel
) = NavigationScreen(title = "moko-biometry") { paddingValues ->
    BindBiometryAuthenticatorEffect(viewModel.biometryAuthenticator)

    val text: String by viewModel.result.collectAsState()

    Column(
        modifier = Modifier.fillMaxSize().padding(paddingValues),
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        Text(text = text)

        Button(onClick = viewModel::onButtonClick) {
            Text(text = "Click on me")
        }
    }
}

Samples

Please see more examples in the sample directory.

Set Up Locally

• The biometry directory contains the biometry library;
• The sample directory contains sample apps for Android and iOS; plus the mpp-library connected to the apps.

Contributing

All development (both new features and bug fixes) is performed in the develop branch. This way master always contains the sources of the most recently released version. Please send PRs with bug fixes to the develop branch. Documentation fixes in the markdown files are an exception to this rule. They are updated directly in master.

The develop branch is pushed to master on release.

For more details on contributing please see the contributing guide.

License

Copyright 2021 IceRock MAG Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.