Auth Emulator support

FirebaseAuth/Sources/Auth/FIRAuth.m

@@ -1462,6 +1462,26 @@ - (void)useAppLanguage {
   });
 }
 
+- (void)useEmulatorWithHost:(NSString *)host port:(NSInteger)port {
+  NSAssert(host.length > 0, @"Cannot connect to nil or empty host");
+
+  NSString *formattedHost;
+  if ([host containsString:@":"]) {
+    // Host is an IPv6 address and should be formatted with surrounding brackets.
+    formattedHost = [NSString stringWithFormat:@"[%@]", host];
+  } else {
+    formattedHost = host;
+  }
+
+  dispatch_sync(FIRAuthGlobalWorkQueue(), ^{
+    self->_requestConfiguration.emulatorHostAndPort =
+        [NSString stringWithFormat:@"%@:%ld", formattedHost, (long)port];
+#if TARGET_OS_IOS
+    self->_settings.appVerificationDisabledForTesting = YES;
+#endif
+  });
+}
+
 - (nullable NSString *)languageCode {
   return _requestConfiguration.languageCode;
 }

FirebaseAuth/Sources/Auth/FIRAuth_Internal.h

@@ -142,6 +142,11 @@ NS_ASSUME_NONNULL_BEGIN
 - (FIRAuthDataResultCallback)signInFlowAuthDataResultCallbackByDecoratingCallback:
     (nullable FIRAuthDataResultCallback)callback;
 
+/** @fn useEmulatorWithHost:port
+    @brief Configures Firebase Auth to connect to an emulated host instead of the remote backend.
+ */
+- (void)useEmulatorWithHost:(NSString *)host port:(NSInteger)port;
+
 @end
 
 NS_ASSUME_NONNULL_END

FirebaseAuth/Sources/AuthProvider/OAuth/FIROAuthProvider.m

@@ -47,6 +47,11 @@ typedef void (^FIRHeadfulLiteURLCallBack)(NSURL *_Nullable headfulLiteURL,
  */
 NSString *const kHeadfulLiteURLStringFormat = @"https://%@/__/auth/handler?%@";
 
+/** @var kHeadfulLiteEmulatorURLStringFormat
+    @brief The format of the URL used to open the emulated headful lite page during sign-in.
+ */
+NSString *const kHeadfulLiteEmulatorURLStringFormat = @"http://%@/emulator/auth/handler?%@";
+
 /** @var kauthTypeSignInWithRedirect
     @brief The auth type to be specified in the sign-in request with redirect request and response.
  */
@@ -323,9 +328,17 @@ - (void)getHeadFulLiteURLWithEventID:(NSString *)eventID
                                      }
                                      NSString *argumentsString = [strongSelf
                                          httpArgumentsStringForArgsDictionary:urlArguments];
-                                     NSString *URLString =
-                                         [NSString stringWithFormat:kHeadfulLiteURLStringFormat,
-                                                                    authDomain, argumentsString];
+                                     NSString *URLString;
+                                     if (strongSelf->_auth.requestConfiguration
+                                             .emulatorHostAndPort) {
+                                       URLString = [NSString
+                                           stringWithFormat:kHeadfulLiteEmulatorURLStringFormat,
+                                                            authDomain, argumentsString];
+                                     } else {
+                                       URLString =
+                                           [NSString stringWithFormat:kHeadfulLiteURLStringFormat,
+                                                                      authDomain, argumentsString];
+                                     }
                                      if (completion) {
                                        NSCharacterSet *set =
                                            [NSCharacterSet URLFragmentAllowedCharacterSet];

FirebaseAuth/Sources/Backend/FIRAuthBackend.m

@@ -650,6 +650,10 @@ - (void)asyncPostToURLWithRequestConfiguration:(FIRAuthRequestConfiguration *)re
     [request setValue:languageCode forHTTPHeaderField:kFirebaseLocalHeader];
   }
   GTMSessionFetcher *fetcher = [_fetcherService fetcherWithRequest:request];
+  NSString *emulatorHostAndPort = requestConfiguration.emulatorHostAndPort;
+  if (emulatorHostAndPort) {
+    fetcher.allowLocalhostRequest = YES;
+  }
   fetcher.bodyData = body;
   [fetcher beginFetchWithCompletionHandler:handler];
 }

FirebaseAuth/Sources/Backend/FIRAuthRequestConfiguration.h

@@ -40,6 +40,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, copy, nullable) NSString *additionalFrameworkMarker;
 
+/** @property emulatorHostAndPort
+    @brief If set, the local emulator host and port to point to instead of the remote backend.
+ */
+@property(nonatomic, copy, nullable) NSString *emulatorHostAndPort;
+
 - (instancetype)init NS_UNAVAILABLE;
 
 /** @fn initWithRequestClass:APIKey:authLanguage:

FirebaseAuth/Sources/Backend/FIRIdentityToolkitRequest.m

@@ -20,9 +20,13 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+static NSString *const kHttpsProtocol = @"https:";
+static NSString *const kHttpProtocol = @"http:";
+
 static NSString *const kFirebaseAuthAPIURLFormat =
-    @"https://%@/identitytoolkit/v3/relyingparty/%@?key=%@";
-static NSString *const kIdentityPlatformAPIURLFormat = @"https://%@/v2/%@?key=%@";
+    @"%@//%@/identitytoolkit/v3/relyingparty/%@?key=%@";
+static NSString *const kIdentityPlatformAPIURLFormat = @"%@//%@/v2/%@?key=%@";
+static NSString *const kEmulatorHostAndPrefixFormat = @"%@/%@";
 
 static NSString *gAPIHost = @"www.googleapis.com";
 
@@ -80,23 +84,39 @@ - (BOOL)containsPostBody {
 
 - (NSURL *)requestURL {
   NSString *apiURLFormat;
-  NSString *apiHost;
+  NSString *apiProtocol;
+  NSString *apiHostAndPathPrefix;
+
+  NSString *emulatorHostAndPort = _requestConfiguration.emulatorHostAndPort;
+
   if (_useIdentityPlatform) {
     apiURLFormat = kIdentityPlatformAPIURLFormat;
-    if (_useStaging) {
-      apiHost = kIdentityPlatformStagingAPIHost;
+    apiProtocol = kHttpsProtocol;
+    if (emulatorHostAndPort) {
+      apiProtocol = kHttpProtocol;
+      apiHostAndPathPrefix =
+          [NSString stringWithFormat:kEmulatorHostAndPrefixFormat, emulatorHostAndPort,
+                                     kIdentityPlatformAPIHost];
+    } else if (_useStaging) {
+      apiHostAndPathPrefix = kIdentityPlatformStagingAPIHost;
     } else {
-      apiHost = kIdentityPlatformAPIHost;
+      apiHostAndPathPrefix = kIdentityPlatformAPIHost;
     }
   } else {
     apiURLFormat = kFirebaseAuthAPIURLFormat;
-    if (_useStaging) {
-      apiHost = kFirebaseAuthStagingAPIHost;
+    apiProtocol = kHttpsProtocol;
+    if (emulatorHostAndPort) {
+      apiProtocol = kHttpProtocol;
+      apiHostAndPathPrefix = [NSString
+          stringWithFormat:kEmulatorHostAndPrefixFormat, emulatorHostAndPort, kFirebaseAuthAPIHost];
+    } else if (_useStaging) {
+      apiHostAndPathPrefix = kFirebaseAuthStagingAPIHost;
     } else {
-      apiHost = kFirebaseAuthAPIHost;
+      apiHostAndPathPrefix = kFirebaseAuthAPIHost;
     }
   }
-  NSString *URLString = [NSString stringWithFormat:apiURLFormat, apiHost, _endpoint, _APIKey];
+  NSString *URLString = [NSString
+      stringWithFormat:apiURLFormat, apiProtocol, apiHostAndPathPrefix, _endpoint, _APIKey];
   NSURL *URL = [NSURL URLWithString:URLString];
   return URL;
 }

FirebaseAuth/Sources/Backend/RPC/FIRSecureTokenRequest.m

@@ -26,6 +26,12 @@
  */
 static NSString *const kFIRSecureTokenServiceGetTokenURLFormat = @"https://%@/v1/token?key=%@";
 
+/** @var kFIREmulatorURLFormat
+    @brief The format of the emulated secure token service URLs. Requires string format substitution
+   with the emulator host, the gAPIHost, and the client's API Key.
+ */
+static NSString *const kFIREmulatorURLFormat = @"http://%@/%@/v1/token?key=%@";
+
 /** @var kFIRSecureTokenServiceGrantTypeRefreshToken
     @brief The string value of the @c FIRSecureTokenRequestGrantTypeRefreshToken request type.
  */
@@ -123,8 +129,16 @@ - (FIRAuthRequestConfiguration *)requestConfiguration {
 }
 
 - (NSURL *)requestURL {
-  NSString *URLString =
-      [NSString stringWithFormat:kFIRSecureTokenServiceGetTokenURLFormat, gAPIHost, _APIKey];
+  NSString *URLString;
+
+  NSString *emulatorHostAndPort = _requestConfiguration.emulatorHostAndPort;
+  if (emulatorHostAndPort) {
+    URLString =
+        [NSString stringWithFormat:kFIREmulatorURLFormat, emulatorHostAndPort, gAPIHost, _APIKey];
+  } else {
+    URLString =
+        [NSString stringWithFormat:kFIRSecureTokenServiceGetTokenURLFormat, gAPIHost, _APIKey];
+  }
   NSURL *URL = [NSURL URLWithString:URLString];
   return URL;
 }

FirebaseAuth/Sources/Utilities/FIRAuthWebUtils.m

@@ -86,6 +86,12 @@ + (BOOL)isExpectedCallbackURL:(nullable NSURL *)URL
 
 + (void)fetchAuthDomainWithRequestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration
                                      completion:(FIRFetchAuthDomainCallback)completion {
+  if (requestConfiguration.emulatorHostAndPort) {
+    // If we are using the auth emulator, we do not want to call the GetProjectConfig endpoint. The
+    // widget is hosted on the emulator host and port, so we can return that directly.
+    completion(requestConfiguration.emulatorHostAndPort, nil);
+    return;
+  }
   FIRGetProjectConfigRequest *request =
       [[FIRGetProjectConfigRequest alloc] initWithRequestConfiguration:requestConfiguration];
 

FirebaseAuth/Tests/Unit/FIRAuthTests.m

@@ -20,6 +20,7 @@
 
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRActionCodeSettings.h"
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRAdditionalUserInfo.h"
+#import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRAuthSettings.h"
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIREmailAuthProvider.h"
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRFacebookAuthProvider.h"
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRGoogleAuthProvider.h"
@@ -2191,6 +2192,41 @@ - (void)testIDTokenChanges {
   [self waitForTimeIntervel:kWaitInterval];  // make sure listener is no longer called
 }
 
+/** @fn testUseEmulator
+    @brief Tests the @c useEmulatorWithHost:port: method.
+ */
+- (void)testUseEmulator {
+  [[FIRAuth auth] useEmulatorWithHost:@"host" port:12345];
+
+  XCTAssertEqualObjects(@"host:12345", [FIRAuth auth].requestConfiguration.emulatorHostAndPort);
+#if TARGET_OS_IOS
+  XCTAssertTrue([FIRAuth auth].settings.isAppVerificationDisabledForTesting);
+#endif
+}
+
+/** @fn testUseEmulatorNeverCalled
+    @brief Tests that the emulatorHostAndPort stored in @c FIRAuthRequestConfiguration is nil if the
+   @c useEmulatorWithHost:port: is not called.
+ */
+- (void)testUseEmulatorNeverCalled {
+  XCTAssertEqualObjects(nil, [FIRAuth auth].requestConfiguration.emulatorHostAndPort);
+#if TARGET_OS_IOS
+  XCTAssertFalse([FIRAuth auth].settings.isAppVerificationDisabledForTesting);
+#endif
+}
+
+/** @fn testUseEmulatorIPv6Address
+    @brief Tests the @c useEmulatorWithHost:port: method with an IPv6 host address.
+ */
+- (void)testUseEmulatorIPv6Address {
+  [[FIRAuth auth] useEmulatorWithHost:@"::1" port:12345];
+
+  XCTAssertEqualObjects(@"[::1]:12345", [FIRAuth auth].requestConfiguration.emulatorHostAndPort);
+#if TARGET_OS_IOS
+  XCTAssertTrue([FIRAuth auth].settings.isAppVerificationDisabledForTesting);
+#endif
+}
+
 #pragma mark - Automatic Token Refresh Tests.
 
 /** @fn testAutomaticTokenRefresh