Add new LocalAuthenticationService type

Release Notes.md

@@ -6,6 +6,11 @@
 ### ✨ New features
 
 * `LAContext+Async` adds an async policy evaluation function.
+* `LocalAuthenticationService` is a new service that lets you use any local authentication policy.
+
+### 💡 Behavior changes
+
+* `BiometricAuthenticationService` now inherits and specializes `LocalAuthenticationService`.    
 
 
 

Sources/SwiftKit/Authentication/AuthenticationService.swift

@@ -19,14 +19,24 @@ public protocol AuthenticationService: AnyObject {
     typealias AuthResult = Result<Void, Error>
     
     /**
-     Authenticate the user for a certain authentication type.
+     Authenticate the user for a certain ``Authentication``.
      
-     `reason` can be used to display information to the user.
+     - Parameters:
+       - auth: The authentication type to evaluate.
+       - reason: The localized reason to show to the user.
+       - completion: The completion block to call once authentication is done.
      */
-    func authenticateUser(for auth: Authentication, reason: String, completion: @escaping AuthCompletion)
+    func authenticateUser(
+        for auth: Authentication,
+        reason: String,
+        completion: @escaping AuthCompletion)
     
     /**
-     Check if the service instance can authenticate the user.
+     Whether or not the service can authenticate the current
+     user for a certain ``Authentication`` type.
+     
+     - Parameters:
+       - auth: The authentication type to evaluate.
      */
     func canAuthenticateUser(for auth: Authentication) -> Bool
 }

Sources/SwiftKit/Authentication/BiometricAuthenticationService.swift

@@ -13,52 +13,13 @@ import LocalAuthentication
  This authentication service uses `LocalAuthentication` such
  as `FaceID` or `TouchID` to authenticate the user.
  */
-public class BiometricAuthenticationService: AuthenticationService {
-    
-    public init() {}
-    
-    
-    private let policy = LAPolicy.deviceOwnerAuthenticationWithBiometrics
-    
+public class BiometricAuthenticationService: LocalAuthenticationService {
     
     /**
-     Authenticate the user for a certain authentication type.
-     
-     `reason` can be used to display information to the user.
+     Create a service instance.
      */
-    public func authenticateUser(for auth: Authentication, reason: String, completion: @escaping AuthCompletion) {
-        guard canAuthenticateUser(for: auth) else { return completion(.failure(AuthError.unsupportedAuthentication)) }
-        performAuthentication(for: auth, reason: reason) { result in
-            DispatchQueue.main.async { completion(result) }
-        }
-    }
-    
-    /**
-     Check if the service instance can authenticate the user.
-     
-     For instance, a user can disable authentication for the
-     app, which means that the service can no longer fulfill
-     it's intended use.
-     */
-    public func canAuthenticateUser(for auth: Authentication) -> Bool {
-        var error: NSError?
-        return LAContext().canEvaluatePolicy(policy, error: &error)
-    }
-    
-    /**
-     Authenticate the user for a certain authentication type,
-     regardless of if this service can authenticate the user
-     for the provided authentication type or not.
-     
-     This is a way to bypass any particular rules and states
-     of the service and is not part of the service protocol.
-     */
-    public func performAuthentication(for auth: Authentication, reason: String, completion: @escaping AuthCompletion) {
-        LAContext().evaluatePolicy(policy, localizedReason: reason) { result, error in
-            if let error = error { return completion(.failure(error)) }
-            if result == false { return completion(.failure(AuthError.authenticationFailed)) }
-            completion(.success(()))
-        }
+    public init() {
+        super.init(policy: .deviceOwnerAuthenticationWithBiometrics)
     }
 }
 #endif

Sources/SwiftKit/Authentication/LocalAuthenticationService.swift

@@ -0,0 +1,79 @@
+//
+//  LocalAuthenticationService.swift
+//  SwiftKit
+//
+//  Created by Daniel Saidi on 2022-04-29.
+//  Copyright © 2022 Daniel Saidi. All rights reserved.
+//
+
+#if os(iOS) || os(macOS)
+import LocalAuthentication
+
+/**
+ This service uses `LocalAuthentication` to authenticate the
+ current user.
+ */
+open class LocalAuthenticationService: AuthenticationService {
+    
+    /**
+     Create a service instance.
+
+     - Parameters:
+       - policy: The authentication policy to use.
+     */
+    public init(policy: LAPolicy) {
+        self.policy = policy
+    }
+    
+    
+    private let policy: LAPolicy
+    
+    
+    /**
+     Authenticate the user for a certain ``Authentication``.
+     
+     - Parameters:
+       - auth: The authentication type to evaluate.
+       - reason: The localized reason to show to the user.
+     */
+    open func authenticateUser(for auth: Authentication, reason: String, completion: @escaping AuthCompletion) {
+        guard canAuthenticateUser(for: auth) else { return completion(.failure(AuthError.unsupportedAuthentication)) }
+        performAuthentication(for: auth, reason: reason) { result in
+            DispatchQueue.main.async { completion(result) }
+        }
+    }
+    
+    /**
+     Check if the service instance can authenticate the user
+     for a certain ``Authentication``.
+     
+     For biometric authentication, a user can disable system
+     authentication for an app, which means that the service
+     can no longer fulfill it's intended use.
+     
+     - Parameters:
+       - auth: The authentication type to evaluate.
+     */
+    open func canAuthenticateUser(for auth: Authentication) -> Bool {
+        var error: NSError?
+        return LAContext().canEvaluatePolicy(policy, error: &error)
+    }
+    
+    /**
+     Authenticate the user for a certain `` authentication type,
+     regardless of if this service can authenticate the user
+     for the provided authentication type or not.
+     
+     This is a way to bypass any particular rules and states
+     of the service and can be used to e.g. mock .
+     */
+    open func performAuthentication(for auth: Authentication, reason: String, completion: @escaping AuthCompletion) {
+        LAContext().evaluatePolicy(policy, localizedReason: reason) { result, error in
+            if let error = error { return completion(.failure(error)) }
+            if result == false { return completion(.failure(AuthError.authenticationFailed)) }
+            completion(.success(()))
+        }
+    }
+}
+#endif
+