Exchange token tests

ExchangeTokenRequestTests.swift

@@ -0,0 +1,154 @@
+// Copyright 2023 Google LLC
+//
+// 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.
+
+import Foundation
+import XCTest
+
+@testable import FirebaseAuth
+import FirebaseCore
+
+/// Tests for `ExchangeTokenRequest`
+@available(iOS 13, *)
+class ExchangeTokenRequestTests: XCTestCase {
+  // MARK: - Constants for Testing
+
+  let kAPIKey = "test-api-key"
+  let kProjectID = "test-project-id"
+  let kLocation = "us-east1"
+  let kTenantID = "test-tenant-id-123"
+  let kIdToken = "a-very-long-and-secure-oidc-token-string"
+  let kIdpConfigId = "oidc.my-test-provider"
+
+  let kProductionHost = "identityplatform.googleapis.com"
+  let kStagingHost = "staging-identityplatform.sandbox.googleapis.com"
+
+  // MARK: - Test Cases
+
+  /// Tests that the production URL is correctly formed for a specific region.
+  func testProductionURLIsCorrectlyConstructed() {
+    let (auth, app) = createTestAuthInstance(
+      projectID: kProjectID,
+      location: kLocation,
+      tenantId: kTenantID
+    )
+
+    let request = ExchangeTokenRequest(
+      idToken: kIdToken,
+      idpConfigID: kIdpConfigId,
+      config: auth.requestConfiguration,
+      useStaging: false
+    )
+
+    let expectedHost = "\(kLocation)-\(kProductionHost)"
+    let expectedURL = "https://\(expectedHost)/v2beta/projects/\(kProjectID)" +
+      "/locations/\(kLocation)/tenants/\(kTenantID)/idpConfigs/\(kIdpConfigId):exchangeOidcToken?key=\(kAPIKey)"
+
+    XCTAssertEqual(request.requestURL().absoluteString, expectedURL)
+  }
+
+  /// Tests that the production URL is correctly formed for the "prod-global" location.
+  func testProductionURLIsCorrectlyConstructedForGlobalLocation() {
+    let (auth, app) = createTestAuthInstance(
+      projectID: kProjectID,
+      location: "prod-global",
+      tenantId: kTenantID
+    )
+    _ = app
+
+    let request = ExchangeTokenRequest(
+      idToken: kIdToken,
+      idpConfigID: kIdpConfigId,
+      config: auth.requestConfiguration,
+      useStaging: false
+    )
+
+    let expectedHost = kProductionHost
+    let expectedURL = "https://\(expectedHost)/v2beta/projects/\(kProjectID)" +
+      "/locations/global/tenants/\(kTenantID)/idpConfigs/\(kIdpConfigId):exchangeOidcToken?key=\(kAPIKey)"
+
+    XCTAssertEqual(request.requestURL().absoluteString, expectedURL)
+  }
+
+  /// Tests that the staging URL is correctly formed.
+  func testStagingURLIsCorrectlyConstructed() {
+    let (auth, app) = createTestAuthInstance(
+      projectID: kProjectID,
+      location: kLocation,
+      tenantId: kTenantID
+    )
+    _ = app
+
+    let request = ExchangeTokenRequest(
+      idToken: kIdToken,
+      idpConfigID: kIdpConfigId,
+      config: auth.requestConfiguration,
+      useStaging: true
+    )
+
+    let expectedHost = "\(kLocation)-\(kStagingHost)"
+    let expectedURL = "https://\(expectedHost)/v2beta/projects/\(kProjectID)" +
+      "/locations/\(kLocation)/tenants/\(kTenantID)/idpConfigs/\(kIdpConfigId):exchangeOidcToken?key=\(kAPIKey)"
+
+    XCTAssertEqual(request.requestURL().absoluteString, expectedURL)
+  }
+
+  /// Tests that the unencoded HTTP body contains the correct id_token.
+  func testUnencodedHTTPBodyIsCorrect() {
+    let (auth, app) = createTestAuthInstance(
+      projectID: kProjectID,
+      location: kLocation,
+      tenantId: kTenantID
+    )
+    _ = app
+
+    let request = ExchangeTokenRequest(
+      idToken: kIdToken,
+      idpConfigID: kIdpConfigId,
+      config: auth.requestConfiguration
+    )
+
+    let body = request.unencodedHTTPRequestBody
+    XCTAssertNotNil(body)
+    XCTAssertEqual(body?.count, 1)
+    XCTAssertEqual(body?["id_token"] as? String, kIdToken)
+  }
+
+  // MARK: - Helper Function
+
+  /// Creates a test FirebaseApp and Auth instance with specified configurations.
+  private func createTestAuthInstance(projectID: String?, location: String?,
+                                      tenantId: String?) -> (auth: Auth, app: FirebaseApp) {
+    let appName = "TestApp-\(UUID().uuidString)"
+    let options = FirebaseOptions(
+      googleAppID: "1:1234567890:ios:abcdef123456",
+      gcmSenderID: "1234567890"
+    )
+    options.apiKey = kAPIKey
+    if let projectID = projectID {
+      options.projectID = projectID
+    }
+
+    if FirebaseApp.app(name: appName) != nil {
+      FirebaseApp.app(name: appName)?.delete { _ in }
+    }
+    let app = FirebaseApp(instanceWithName: appName, options: options)
+
+    let auth = Auth(app: app)
+    auth.app = app
+    auth.requestConfiguration.location = location
+    auth.requestConfiguration.tenantId = tenantId
+
+    return (auth, app)
+  }
+}

FirebaseAuth/Sources/Swift/Auth/Auth.swift

@@ -18,6 +18,7 @@ import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
 import FirebaseCoreExtension
+import FirebaseCoreInternal
 #if COCOAPODS
   internal import GoogleUtilities
 #else
@@ -83,48 +84,74 @@ extension Auth: AuthInterop {
   public func getToken(forcingRefresh forceRefresh: Bool,
                        completion callback: @escaping (String?, Error?) -> Void) {
     kAuthGlobalWorkQueue.async { [weak self] in
-      if let strongSelf = self {
-        // Enable token auto-refresh if not already enabled.
-        if !strongSelf.autoRefreshTokens {
-          AuthLog.logInfo(code: "I-AUT000002", message: "Token auto-refresh enabled.")
-          strongSelf.autoRefreshTokens = true
-          strongSelf.scheduleAutoTokenRefresh()
-
-          #if os(iOS) || os(tvOS) // TODO(ObjC): Is a similar mechanism needed on macOS?
-            strongSelf.applicationDidBecomeActiveObserver =
-              NotificationCenter.default.addObserver(
-                forName: UIApplication.didBecomeActiveNotification,
-                object: nil, queue: nil
-              ) { notification in
-                if let strongSelf = self {
-                  strongSelf.isAppInBackground = false
-                  if !strongSelf.autoRefreshScheduled {
-                    strongSelf.scheduleAutoTokenRefresh()
-                  }
-                }
-              }
-            strongSelf.applicationDidEnterBackgroundObserver =
-              NotificationCenter.default.addObserver(
-                forName: UIApplication.didEnterBackgroundNotification,
-                object: nil, queue: nil
-              ) { notification in
-                if let strongSelf = self {
-                  strongSelf.isAppInBackground = true
-                }
-              }
-          #endif
+      guard let self else {
+        DispatchQueue.main.async { callback(nil, nil) }
+        return
+      }
+      /// Before checking for a standard user, check if we are in a token-only session established
+      /// by a successful exchangeToken call.
+      let rGCIPToken = self.rGCIPFirebaseTokenLock.withLock { $0 }
+
+      if let token = rGCIPToken {
+        /// Logic for tokens obtained via exchangeToken (R-GCIP mode)
+        if token.expirationDate < Date() {
+          /// Token expired
+          let error = AuthErrorUtils
+            .userTokenExpiredError(
+              message: "The firebase access token obtained via exchangeToken() has expired."
+            )
+          Auth.wrapMainAsync(callback: callback, with: .failure(error))
+        } else if forceRefresh {
+          /// Token is not expired, but forceRefresh was requested which is currently unsupported
+          let error = AuthErrorUtils
+            .operationNotAllowedError(
+              message: "forceRefresh is not supported for firebase access tokens obtained via exchangeToken()."
+            )
+          Auth.wrapMainAsync(callback: callback, with: .failure(error))
+        } else {
+          /// The token is valid and not expired.
+          Auth.wrapMainAsync(callback: callback, with: .success(token.token))
         }
+        /// Exit here as this path is for rGCIPFirebaseToken only.
+        return
+      }
+      /// Fallback to standard `currentUser` logic if not in token-only mode.
+      if !self.autoRefreshTokens {
+        AuthLog.logInfo(code: "I-AUT000002", message: "Token auto-refresh enabled.")
+        self.autoRefreshTokens = true
+        self.scheduleAutoTokenRefresh()
+
+        #if os(iOS) || os(tvOS)
+          self.applicationDidBecomeActiveObserver =
+            NotificationCenter.default.addObserver(
+              forName: UIApplication.didBecomeActiveNotification,
+              object: nil,
+              queue: nil
+            ) { [weak self] _ in
+              guard let self = self, !self.isAppInBackground,
+                    !self.autoRefreshScheduled else { return }
+              self.scheduleAutoTokenRefresh()
+            }
+          self.applicationDidEnterBackgroundObserver =
+            NotificationCenter.default.addObserver(
+              forName: UIApplication.didEnterBackgroundNotification,
+              object: nil,
+              queue: nil
+            ) { [weak self] _ in
+              self?.isAppInBackground = true
+            }
+        #endif
       }
-      // Call back with 'nil' if there is no current user.
-      guard let strongSelf = self, let currentUser = strongSelf._currentUser else {
+
+      guard let currentUser = self._currentUser else {
         DispatchQueue.main.async {
           callback(nil, nil)
         }
         return
       }
       // Call back with current user token.
       currentUser
-        .internalGetToken(forceRefresh: forceRefresh, backend: strongSelf.backend) { token, error in
+        .internalGetToken(forceRefresh: forceRefresh, backend: self.backend) { token, error in
           DispatchQueue.main.async {
             callback(token, error)
           }
@@ -2265,6 +2292,11 @@ extension Auth: AuthInterop {
     return { result in
       switch result {
       case let .success(authResult):
+        /// When a standard user successfully signs in, any existing token-only session must be
+        /// invalidated to prevent a conflicting auth state.
+        /// Clear any R-GCIP session state when a standard user signs in. This ensures we exit
+        /// Token-Only Mode.
+        self.rGCIPFirebaseTokenLock.withLock { $0 = nil }
         do {
           try self.updateCurrentUser(authResult.user, byForce: false, savingToDisk: true)
           Auth.wrapMainAsync(callback: callback, with: .success(authResult))
@@ -2428,9 +2460,20 @@ extension Auth: AuthInterop {
   ///
   /// Mutations should occur within a @synchronized(self) context.
   private var listenerHandles: NSMutableArray = []
+
+  // R-GCIP Token-Only Session State
+
+  /// The session token obtained from a successful `exchangeToken` call, protected by a lock.
+  ///
+  /// This property is used to support a "token-only" authentication mode for Regionalized
+  /// GCIP, where no `User` object is created. It is mutually exclusive with `_currentUser`.
+  /// If the wrapped value is non-nil, the `AuthInterop` layer will use it for token generation
+  /// instead of relying on a `currentUser`.
+  private let rGCIPFirebaseTokenLock = FIRAllocatedUnfairLock<FirebaseToken?>(initialState: nil)
 }
 
-/// Regionalized auth
+// MARK: - Regionalized auth
+
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
 public extension Auth {
   /// Gets the Auth object for a `FirebaseApp` configured for a specific Regional Google Cloud
@@ -2511,10 +2554,18 @@ public extension Auth {
     )
     do {
       let response = try await backend.call(with: request)
-      return FirebaseToken(
+      let newToken = FirebaseToken(
         token: response.firebaseToken,
         expirationDate: response.expirationDate
       )
+      // Lock and update the token, signing out any current user.
+      rGCIPFirebaseTokenLock.withLock { token in
+        if self._currentUser != nil {
+          try? self.signOut()
+        }
+        token = newToken
+      }
+      return newToken
     } catch {
       throw error
     }

FirebaseAuth/Sources/Swift/Backend/RPC/IdentityPlatform/ExchangeTokenRequest.swift

@@ -14,8 +14,8 @@
 
 import Foundation
 
-private let regionalGCIPAPIHost = "identityplatform.googleapis.com"
-private let regionalGCIPStagingAPIHost = "staging-identityplatform.sandbox.googleapis.com"
+private let kRegionalGCIPAPIHost = "identityplatform.googleapis.com"
+private let kRegionalGCIPStagingAPIHost = "staging-identityplatform.sandbox.googleapis.com"
 
 // MARK: - ExchangeTokenRequest
 
@@ -44,14 +44,6 @@ struct ExchangeTokenRequest: AuthRPCRequest {
   /// Flag for whether to use the staging backend.
   let useStaging: Bool
 
-  /// The base URL components for the request, will be used to construct the final URL.
-  private var baseURLComponents: URLComponents {
-    var components = URLComponents()
-    components.scheme = "https"
-    components.host = useStaging ? regionalGCIPStagingAPIHost : regionalGCIPAPIHost
-    return components
-  }
-
   /// Initializes an `ExchangeTokenRequest`.
   ///
   /// - Parameters:
@@ -89,16 +81,16 @@ struct ExchangeTokenRequest: AuthRPCRequest {
         "Internal Error: ExchangeTokenRequest requires `location`, `tenantId`, and `projectID`."
       )
     }
-    var components = baseURLComponents
-    if location != "global" {
-      components.host = "\(location)-\(components.host ?? "")"
-    }
-    let locationPath = location == "global" ? "global" : location
-    components
-      .path =
-      "/v2beta/projects/\(project)/locations/\(locationPath)/tenants/\(tenant)/idpConfigs/\(idpConfigID):exchangeOidcToken"
-    components.queryItems = [URLQueryItem(name: "key", value: config.apiKey)]
-    guard let url = components.url else {
+    let baseHost = useStaging ? kRegionalGCIPStagingAPIHost : kRegionalGCIPAPIHost
+    let host = (location == "prod-global" || location == "global") ? baseHost :
+      "\(location)-\(baseHost)"
+
+    let locationPath = (location == "prod-global") ? "global" : location
+
+    let path = "/v2beta/projects/\(project)/locations/\(locationPath)" +
+      "/tenants/\(tenant)/idpConfigs/\(idpConfigID):exchangeOidcToken"
+
+    guard let url = URL(string: "https://\(host)\(path)?key=\(config.apiKey)") else {
       fatalError("Failed to create URL for ExchangeTokenRequest")
     }
     return url