refactor: simplify Auth dependency system (#278)

* refactor: simplify Auth dependency system

* Remove unused code from tests

* wip

Author: Guilherme Souza

Sources/Auth/AuthAdmin.swift

@@ -9,13 +9,11 @@ import Foundation
 @_spi(Internal) import _Helpers
 
 public actor AuthAdmin {
-  private var configuration: AuthClient.Configuration {
-    Dependencies.current.value!.configuration
-  }
+  @Dependency(\.configuration)
+  private var configuration: AuthClient.Configuration
 
-  private var api: APIClient {
-    Dependencies.current.value!.api
-  }
+  @Dependency(\.api)
+  private var api: APIClient
 
   /// Delete a user. Requires `service_role` key.
   /// - Parameter id: The id of the user you want to delete.

Sources/Auth/AuthClient.swift

@@ -56,33 +56,26 @@ public actor AuthClient {
     }
   }
 
-  private var configuration: Configuration {
-    Dependencies.current.value!.configuration
-  }
+  @Dependency(\.configuration)
+  private var configuration: Configuration
 
-  private var api: APIClient {
-    Dependencies.current.value!.api
-  }
+  @Dependency(\.api)
+  private var api: APIClient
 
-  private var sessionManager: any SessionManager {
-    Dependencies.current.value!.sessionManager
-  }
+  @Dependency(\.eventEmitter)
+  private var eventEmitter: EventEmitter
 
-  private var codeVerifierStorage: CodeVerifierStorage {
-    Dependencies.current.value!.codeVerifierStorage
-  }
+  @Dependency(\.sessionManager)
+  private var sessionManager: SessionManager
 
-  private var eventEmitter: any EventEmitter {
-    Dependencies.current.value!.eventEmitter
-  }
+  @Dependency(\.codeVerifierStorage)
+  private var codeVerifierStorage: CodeVerifierStorage
 
-  private var currentDate: @Sendable () -> Date {
-    Dependencies.current.value!.currentDate
-  }
+  @Dependency(\.currentDate)
+  private var currentDate: @Sendable () -> Date
 
-  private var logger: (any SupabaseLogger)? {
-    Dependencies.current.value!.logger
-  }
+  @Dependency(\.logger)
+  private var logger: (any SupabaseLogger)?
 
   /// Returns the session, refreshing it if necessary.
   ///
@@ -141,17 +134,20 @@ public actor AuthClient {
   /// - Parameters:
   ///   - configuration: The client configuration.
   public init(configuration: Configuration) {
-    let api = APIClient.live(http: HTTPClient(
-      logger: configuration.logger,
-      fetchHandler: configuration.fetch
-    ))
+    let api = APIClient.live(
+      configuration: configuration,
+      http: HTTPClient(
+        logger: configuration.logger,
+        fetchHandler: configuration.fetch
+      )
+    )
 
     self.init(
       configuration: configuration,
-      sessionManager: DefaultSessionManager.shared,
+      sessionManager: .live,
       codeVerifierStorage: .live,
       api: api,
-      eventEmitter: DefaultEventEmitter.shared,
+      eventEmitter: .live,
       sessionStorage: .live,
       logger: configuration.logger
     )
@@ -160,31 +156,29 @@ public actor AuthClient {
   /// This internal initializer is here only for easy injecting mock instances when testing.
   init(
     configuration: Configuration,
-    sessionManager: any SessionManager,
+    sessionManager: SessionManager,
     codeVerifierStorage: CodeVerifierStorage,
     api: APIClient,
-    eventEmitter: any EventEmitter,
+    eventEmitter: EventEmitter,
     sessionStorage: SessionStorage,
     logger: (any SupabaseLogger)?
   ) {
     mfa = AuthMFA()
     admin = AuthAdmin()
 
-    Dependencies.current.setValue(
-      Dependencies(
-        configuration: configuration,
-        sessionManager: sessionManager,
-        api: api,
-        eventEmitter: eventEmitter,
-        sessionStorage: sessionStorage,
-        sessionRefresher: SessionRefresher(
-          refreshSession: { [weak self] in
-            try await self?.refreshSession(refreshToken: $0) ?? .empty
-          }
-        ),
-        codeVerifierStorage: codeVerifierStorage,
-        logger: logger
-      )
+    Current = Dependencies(
+      configuration: configuration,
+      sessionManager: sessionManager,
+      api: api,
+      eventEmitter: eventEmitter,
+      sessionStorage: sessionStorage,
+      sessionRefresher: SessionRefresher(
+        refreshSession: { [weak self] in
+          try await self?.refreshSession(refreshToken: $0) ?? .empty
+        }
+      ),
+      codeVerifierStorage: codeVerifierStorage,
+      logger: logger
     )
   }
 
@@ -310,7 +304,11 @@ public actor AuthClient {
 
   /// Log in an existing user with an email and password.
   @discardableResult
-  public func signIn(email: String, password: String, captchaToken: String? = nil) async throws -> Session {
+  public func signIn(
+    email: String,
+    password: String,
+    captchaToken: String? = nil
+  ) async throws -> Session {
     try await _signIn(
       request: .init(
         path: "/token",
@@ -329,7 +327,11 @@ public actor AuthClient {
 
   /// Log in an existing user with a phone and password.
   @discardableResult
-  public func signIn(phone: String, password: String, captchaToken: String? = nil) async throws -> Session {
+  public func signIn(
+    phone: String,
+    password: String,
+    captchaToken: String? = nil
+  ) async throws -> Session {
     try await _signIn(
       request: .init(
         path: "/token",
@@ -931,7 +933,7 @@ public actor AuthClient {
 
   private func emitInitialSession(forToken token: ObservationToken) async {
     let session = try? await session
-    eventEmitter.emit(.initialSession, session: session, token: token)
+    eventEmitter.emit(.initialSession, session, token)
   }
 
   private func prepareForPKCE() -> (codeChallenge: String?, codeChallengeMethod: String?) {

Sources/Auth/AuthMFA.swift

@@ -3,21 +3,17 @@ import Foundation
 
 /// Contains the full multi-factor authentication API.
 public actor AuthMFA {
-  private var api: APIClient {
-    Dependencies.current.value!.api
-  }
+  @Dependency(\.api)
+  private var api: APIClient
 
-  private var sessionManager: any SessionManager {
-    Dependencies.current.value!.sessionManager
-  }
+  @Dependency(\.configuration)
+  private var configuration: AuthClient.Configuration
 
-  private var configuration: AuthClient.Configuration {
-    Dependencies.current.value!.configuration
-  }
+  @Dependency(\.sessionManager)
+  private var sessionManager: SessionManager
 
-  private var eventEmitter: any EventEmitter {
-    Dependencies.current.value!.eventEmitter
-  }
+  @Dependency(\.eventEmitter)
+  private var eventEmitter: EventEmitter
 
   /// Starts the enrollment process for a new Multi-Factor Authentication (MFA) factor. This method
   /// creates a new `unverified` factor.

Sources/Auth/Internal/APIClient.swift

@@ -6,12 +6,11 @@ struct APIClient: Sendable {
 }
 
 extension APIClient {
-  static func live(http: HTTPClient) -> Self {
-    var configuration: AuthClient.Configuration {
-      Dependencies.current.value!.configuration
-    }
-
-    return APIClient(
+  static func live(
+    configuration: AuthClient.Configuration,
+    http: HTTPClient
+  ) -> Self {
+    APIClient(
       execute: { request in
         var request = request
         request.headers.merge(configuration.headers) { r, _ in r }
@@ -45,7 +44,9 @@ extension APIClient {
 extension APIClient {
   @discardableResult
   func authorizedExecute(_ request: Request) async throws -> Response {
-    let session = try await Dependencies.current.value!.sessionManager.session()
+    @Dependency(\.sessionManager) var sessionManager
+
+    let session = try await sessionManager.session()
 
     var request = request
     request.headers["Authorization"] = "Bearer \(session.accessToken)"

Sources/Auth/Internal/CodeVerifierStorage.swift

@@ -8,10 +8,8 @@ struct CodeVerifierStorage: Sendable {
 }
 
 extension CodeVerifierStorage {
-  static var live: Self = {
-    var localStorage: any AuthLocalStorage {
-      Dependencies.current.value!.configuration.localStorage
-    }
+  static let live: Self = {
+    @Dependency(\.configuration.localStorage) var localStorage
 
     let key = "supabase.code-verifier"
 

Sources/Auth/Internal/Dependencies.swift

@@ -3,15 +3,42 @@ import ConcurrencyExtras
 import Foundation
 
 struct Dependencies: Sendable {
-  static let current = LockIsolated(Dependencies?.none)
-
   var configuration: AuthClient.Configuration
-  var sessionManager: any SessionManager
+  var sessionManager: SessionManager
   var api: APIClient
-  var eventEmitter: any EventEmitter
+  var eventEmitter: EventEmitter
   var sessionStorage: SessionStorage
   var sessionRefresher: SessionRefresher
   var codeVerifierStorage: CodeVerifierStorage
   var currentDate: @Sendable () -> Date = { Date() }
   var logger: (any SupabaseLogger)?
 }
+
+private let _Current = LockIsolated<Dependencies?>(nil)
+var Current: Dependencies {
+  get {
+    guard let instance = _Current.value else {
+      fatalError("Current should be set before usage.")
+    }
+
+    return instance
+  }
+  set {
+    _Current.withValue { Current in
+      Current = newValue
+    }
+  }
+}
+
+@propertyWrapper
+struct Dependency<Value> {
+  var wrappedValue: Value {
+    Current[keyPath: keyPath]
+  }
+
+  let keyPath: KeyPath<Dependencies, Value>
+
+  init(_ keyPath: KeyPath<Dependencies, Value>) {
+    self.keyPath = keyPath
+  }
+}

Sources/Auth/Internal/EventEmitter.swift

@@ -2,60 +2,53 @@ import ConcurrencyExtras
 import Foundation
 @_spi(Internal) import _Helpers
 
-protocol EventEmitter: Sendable {
-  func attachListener(
+struct EventEmitter: Sendable {
+  var attachListener: @Sendable (
     _ listener: @escaping AuthStateChangeListener
   ) -> ObservationToken
 
-  func emit(
+  var emit: @Sendable (
     _ event: AuthChangeEvent,
-    session: Session?,
-    token: ObservationToken?
-  )
+    _ session: Session?,
+    _ token: ObservationToken?
+  ) -> Void
 }
 
 extension EventEmitter {
   func emit(
     _ event: AuthChangeEvent,
     session: Session?
   ) {
-    emit(event, session: session, token: nil)
+    emit(event, session, nil)
   }
 }
 
-final class DefaultEventEmitter: EventEmitter {
-  static let shared = DefaultEventEmitter()
-
-  private init() {}
-
-  let emitter = _Helpers.EventEmitter<(AuthChangeEvent, Session?)?>(
-    initialEvent: nil,
-    emitsLastEventWhenAttaching: false
-  )
-
-  func attachListener(
-    _ listener: @escaping AuthStateChangeListener
-  ) -> ObservationToken {
-    emitter.attach { event in
-      guard let event else { return }
-      listener(event.0, event.1)
-    }
-  }
-
-  func emit(
-    _ event: AuthChangeEvent,
-    session: Session?,
-    token: ObservationToken? = nil
-  ) {
-    NotificationCenter.default.post(
-      name: AuthClient.didChangeAuthStateNotification,
-      object: nil,
-      userInfo: [
-        AuthClient.authChangeEventInfoKey: event,
-        AuthClient.authChangeSessionInfoKey: session as Any,
-      ]
+extension EventEmitter {
+  static let live: EventEmitter = {
+    let emitter = _Helpers.EventEmitter<(AuthChangeEvent, Session?)?>(
+      initialEvent: nil,
+      emitsLastEventWhenAttaching: false
     )
 
-    emitter.emit((event, session), to: token)
-  }
+    return EventEmitter(
+      attachListener: { listener in
+        emitter.attach { event in
+          guard let event else { return }
+          listener(event.0, event.1)
+        }
+      },
+      emit: { event, session, token in
+        NotificationCenter.default.post(
+          name: AuthClient.didChangeAuthStateNotification,
+          object: nil,
+          userInfo: [
+            AuthClient.authChangeEventInfoKey: event,
+            AuthClient.authChangeSessionInfoKey: session as Any,
+          ]
+        )
+
+        emitter.emit((event, session), to: token)
+      }
+    )
+  }()
 }