feat: email link sign-in

Author: russellwheatley

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthConfiguration.swift

@@ -1,3 +1,4 @@
+import FirebaseAuth
 import Foundation
 
 public final class AuthConfiguration {
@@ -7,18 +8,24 @@ public final class AuthConfiguration {
   let customStringsBundle: Bundle?
   let tosUrl: URL
   let privacyPolicyUrl: URL
+  let emailLinkSignInActionCodeSettings: ActionCodeSettings?
+  let verifyEmailActionCodeSettings: ActionCodeSettings?
 
   public init(shouldHideCancelButton: Bool = false,
               interactiveDismissEnabled: Bool = true,
               shouldAutoUpgradeAnonymousUsers: Bool = false,
               customStringsBundle: Bundle? = nil,
               tosUrl: URL = URL(string: "https://example.com/tos")!,
-              privacyPolicyUrl: URL = URL(string: "https://example.com/privacy")!) {
+              privacyPolicyUrl: URL = URL(string: "https://example.com/privacy")!,
+              emailLinkSignInActionCodeSettings: ActionCodeSettings? = nil,
+              verifyEmailActionCodeSettings: ActionCodeSettings? = nil) {
     self.shouldHideCancelButton = shouldHideCancelButton
     self.interactiveDismissEnabled = interactiveDismissEnabled
     self.shouldAutoUpgradeAnonymousUsers = shouldAutoUpgradeAnonymousUsers
     self.customStringsBundle = customStringsBundle
     self.tosUrl = tosUrl
     self.privacyPolicyUrl = privacyPolicyUrl
+    self.emailLinkSignInActionCodeSettings = emailLinkSignInActionCodeSettings
+    self.verifyEmailActionCodeSettings = verifyEmailActionCodeSettings
   }
 }

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -30,6 +30,13 @@ public enum AuthenticationFlow {
   case signUp
 }
 
+public enum AuthServiceError: Error {
+  case invalidEmailLink(String)
+  case notConfiguredProvider(String)
+  case clientIdNotFound(String)
+  case notConfiguredActionCodeSettings(String)
+}
+
 @MainActor
 final class AuthListenerManager {
   private var authStateHandle: AuthStateDidChangeListenerHandle?
@@ -59,6 +66,7 @@ final class AuthListenerManager {
 @MainActor
 @Observable
 public final class AuthService {
+  @ObservationIgnored @AppStorage("email-link") public var emailLink: String?
   public let configuration: AuthConfiguration
   public let auth: Auth
   private var listenerManager: AuthListenerManager?
@@ -84,13 +92,8 @@ public final class AuthService {
   private var safeGoogleProvider: GoogleProviderProtocol {
     get throws {
       guard let provider = googleProvider else {
-        throw NSError(
-          domain: "AuthEnvironmentErrorDomain",
-          code: 1,
-          userInfo: [
-            NSLocalizedDescriptionKey: "`GoogleProviderSwift` has not been configured",
-          ]
-        )
+        throw AuthServiceError
+          .notConfiguredProvider("`GoogleProviderSwift` has not been configured")
       }
       return provider
     }
@@ -99,18 +102,25 @@ public final class AuthService {
   private var safeFacebookProvider: FacebookProviderProtocol {
     get throws {
       guard let provider = facebookProvider else {
-        throw NSError(
-          domain: "AuthEnvironmentErrorDomain",
-          code: 1,
-          userInfo: [
-            NSLocalizedDescriptionKey: "`FacebookProviderSwift` has not been configured",
-          ]
-        )
+        throw AuthServiceError
+          .notConfiguredProvider("`FacebookProviderSwift` has not been configured")
       }
       return provider
     }
   }
 
+  private func safeActionCodeSettings(emailLinkSignIn: Bool = true) throws -> ActionCodeSettings {
+    guard let actionCodeSettings = emailLinkSignIn ? configuration
+      .emailLinkSignInActionCodeSettings : configuration.verifyEmailActionCodeSettings else {
+      let errorMessage = emailLinkSignIn ?
+        "ActionCodeSettings has not been configured for `AuthConfiguration.emailLinkSignInActionCodeSettings`" :
+        "ActionCodeSettings has not been configured for `AuthConfiguration.verifyEmailActionCodeSettings`"
+      throw AuthServiceError
+        .notConfiguredActionCodeSettings(errorMessage)
+    }
+    return actionCodeSettings
+  }
+
   func updateAuthenticationState() {
     authenticationState =
       (currentUser == nil || currentUser?.isAnonymous == true)
@@ -126,13 +136,12 @@ public final class AuthService {
   public func signInWithGoogle() async throws {
     authenticationState = .authenticating
     do {
-      guard let clientID = auth.app?.options.clientID else { throw NSError(
-        domain: "AuthServiceErrorDomain",
-        code: 2,
-        userInfo: [
-          NSLocalizedDescriptionKey: "OAuth client ID not found. Please make sure Google Sign-In is enabled in the Firebase console. You may have to download a new GoogleService-Info.plist file after enabling Google Sign-In.",
-        ]
-      ) }
+      guard let clientID = auth.app?.options.clientID else {
+        throw AuthServiceError
+          .clientIdNotFound(
+            "OAuth client ID not found. Please make sure Google Sign-In is enabled in the Firebase console. You may have to download a new GoogleService-Info.plist file after enabling Google Sign-In."
+          )
+      }
       let credential = try await safeGoogleProvider.signInWithGoogle(clientID: clientID)
 
       try await signIn(with: credential)
@@ -191,9 +200,7 @@ public final class AuthService {
 
   func sendEmailSignInLink(to email: String) async throws {
     do {
-      // TODO: - how does user set action code settings? Needs configuring
-      let actionCodeSettings = ActionCodeSettings()
-      actionCodeSettings.handleCodeInApp = true
+      let actionCodeSettings = try safeActionCodeSettings()
       try await auth.sendSignInLink(
         toEmail: email,
         actionCodeSettings: actionCodeSettings
@@ -202,4 +209,22 @@ public final class AuthService {
       throw error
     }
   }
+
+  func handleSignInLink(url url: URL) async throws {
+    do {
+      guard let email = emailLink else {
+        throw AuthServiceError.invalidEmailLink(
+          "Invalid email address. Most likely, the link you used has expired. Try signing in again."
+        )
+      }
+      let link = url.absoluteString
+      if auth.isSignIn(withEmailLink: link) {
+        let result = try await auth.signIn(withEmail: email, link: link)
+        updateAuthenticationState()
+        emailLink = nil
+      }
+    } catch {
+      throw error
+    }
+  }
 }

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Views/EmailLinkView.swift

@@ -1,3 +1,4 @@
+import FirebaseAuth
 import SwiftUI
 
 public struct EmailLinkView {
@@ -35,6 +36,7 @@ extension EmailLinkView: View {
       Button(action: {
         Task {
           await sendEmailLink()
+          authService.emailLink = email
         }
       }) {
         Text("Send email sign-in link")
@@ -58,6 +60,14 @@ extension EmailLinkView: View {
         .padding()
       }
       .padding()
+    }.onOpenURL { url in
+      Task {
+        do {
+          try await authService.handleSignInLink(url: url)
+        } catch {
+          errorMessage = authService.string.localizedErrorMessage(for: error)
+        }
+      }
     }
   }
 }

samples/swiftui/FirebaseSwiftUIExample/FirebaseSwiftUIExample/FirebaseSwiftUIExampleApp.swift

@@ -63,7 +63,14 @@ struct ContentView: View {
   let authService: AuthService
 
   init() {
-    authService = AuthService(googleProvider: googleProvider)
+    let actionCodeSettings = ActionCodeSettings()
+    actionCodeSettings.handleCodeInApp = true
+    actionCodeSettings
+      .url = URL(string: "https://flutterfire-e2e-tests.firebaseapp.com")
+    actionCodeSettings.linkDomain = "flutterfire-e2e-tests.firebaseapp.com"
+    actionCodeSettings.setIOSBundleID(Bundle.main.bundleIdentifier!)
+    let configuration = AuthConfiguration(emailLinkSignInActionCodeSettings: actionCodeSettings)
+    authService = AuthService(configuration: configuration, googleProvider: googleProvider)
   }
 
   var body: some View {