Adds Email link sign-in (#882)

16 files changed, 604 insertions, 13 deletions

diff --git a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailAuthProvider.m b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailAuthProvider.m
index d27611e..7a871e2 100644
--- a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailAuthProvider.m
+++ b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailAuthProvider.m
@@ -32,4 +32,8 @@
   return [[FIREmailPasswordAuthCredential alloc] initWithEmail:email password:password];
 }
 
++ (FIRAuthCredential *)credentialWithEmail:(NSString *)email link:(NSString *)link {
+  return [[FIREmailPasswordAuthCredential alloc] initWithEmail:email link:link];
+}
+
 @end
diff --git a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.h b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.h
index d50bf17..7625685 100644
--- a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.h
+++ b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.h
@@ -35,6 +35,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, readonly) NSString *password;
 
+/** @property link
+    @brief The email sign-in link.
+ */
+@property(nonatomic, readonly) NSString *link;
+
 /** @fn initWithEmail:password:
     @brief Designated initializer.
     @param email The user's email address.
@@ -43,6 +48,14 @@ NS_ASSUME_NONNULL_BEGIN
 - (nullable instancetype)initWithEmail:(NSString *)email password:(NSString *)password
     NS_DESIGNATED_INITIALIZER;
 
+/** @fn initWithEmail:link:
+    @brief Designated initializer.
+    @param email The user's email address.
+    @param link The email sign-in link.
+ */
+- (nullable instancetype)initWithEmail:(NSString *)email link:(NSString *)link
+    NS_DESIGNATED_INITIALIZER;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.m b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.m
index 4361366..71cc330 100644
--- a/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.m
+++ b/Firebase/Auth/Source/AuthProviders/EmailPassword/FIREmailPasswordAuthCredential.m
@@ -43,6 +43,15 @@
   return self;
 }
 
+- (nullable instancetype)initWithEmail:(NSString *)email link:(NSString *)link {
+  self = [super initWithProvider:FIREmailAuthProviderID];
+  if (self) {
+    _email = [email copy];
+    _link = [link copy];
+  }
+  return self;
+}
+
 - (void)prepareVerifyAssertionRequest:(FIRVerifyAssertionRequest *)request {
   [FIRAuthExceptionUtils raiseMethodNotImplementedExceptionWithReason:
       @"Attempt to call prepareVerifyAssertionRequest: on a FIREmailPasswordAuthCredential."];
diff --git a/Firebase/Auth/Source/FIRAuth.m b/Firebase/Auth/Source/FIRAuth.m
index 0f3705f..387fab7 100644
--- a/Firebase/Auth/Source/FIRAuth.m
+++ b/Firebase/Auth/Source/FIRAuth.m
@@ -39,6 +39,8 @@
 #import "FIRAuthRequestConfiguration.h"
 #import "FIRCreateAuthURIRequest.h"
 #import "FIRCreateAuthURIResponse.h"
+#import "FIREmailLinkSignInRequest.h"
+#import "FIREmailLinkSignInResponse.h"
 #import "FIRGetOOBConfirmationCodeRequest.h"
 #import "FIRGetOOBConfirmationCodeResponse.h"
 #import "FIRResetPasswordRequest.h"
@@ -117,6 +119,11 @@ static NSString *const kVerifyEmailRequestType = @"VERIFY_EMAIL";
  */
 static NSString *const kRecoverEmailRequestType = @"RECOVER_EMAIL";
 
+/** @var kEmailLinkSignInRequestType
+    @brief The action code type value for an email sign-in link in the check action code response.
+*/
+static NSString *const kEmailLinkSignInRequestType = @"EMAIL_SIGNIN";
+
 /** @var kMissingPasswordReason
     @brief The reason why the @c FIRAuthErrorCodeWeakPassword error is thrown.
     @remarks This error message will be localized in the future.
@@ -186,6 +193,9 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   if ([requestType isEqualToString:kRecoverEmailRequestType]) {
     return FIRActionCodeOperationRecoverEmail;
   }
+  if ([requestType isEqualToString:kEmailLinkSignInRequestType]) {
+    return FIRActionCodeOperationEmailLink;
+  }
   return FIRActionCodeOperationUnknown;
 }
 
@@ -509,6 +519,24 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   });
 }
 
+- (void)fetchSignInMethodsForEmail:(nonnull NSString *)email
+                        completion:(nullable FIRSignInMethodQueryCallback)completion {
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^{
+    FIRCreateAuthURIRequest *request =
+        [[FIRCreateAuthURIRequest alloc] initWithIdentifier:email
+                                                continueURI:@"http://www.google.com/"
+                                       requestConfiguration:_requestConfiguration];
+    [FIRAuthBackend createAuthURI:request callback:^(FIRCreateAuthURIResponse *_Nullable response,
+                                                     NSError *_Nullable error) {
+      if (completion) {
+        dispatch_async(dispatch_get_main_queue(), ^{
+          completion(response.signinMethods, error);
+        });
+      }
+    }];
+  });
+}
+
 - (void)signInWithEmail:(NSString *)email
                password:(NSString *)password
              completion:(FIRAuthResultCallback)completion {
@@ -524,6 +552,23 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   });
 }
 
+- (void)signInWithEmail:(NSString *)email
+                   link:(NSString *)link
+             completion:(FIRAuthDataResultCallback)completion {
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^{
+    FIRAuthDataResultCallback decoratedCallback =
+        [self signInFlowAuthDataResultCallbackByDecoratingCallback:completion];
+    FIREmailPasswordAuthCredential *credential =
+        [[FIREmailPasswordAuthCredential alloc] initWithEmail:email link:link];
+    [self internalSignInAndRetrieveDataWithCredential:credential
+                                   isReauthentication:NO
+                                             callback:^(FIRAuthDataResult *_Nullable authResult,
+                                                        NSError *_Nullable error) {
+      decoratedCallback(authResult, error);
+    }];
+  });
+}
+
 /** @fn signInWithEmail:password:callback:
     @brief Signs in using an email address and password.
     @param email The user's email address.
@@ -536,6 +581,7 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
 - (void)signInWithEmail:(NSString *)email
                password:(NSString *)password
                callback:(FIRAuthResultCallback)callback {
+
   FIRVerifyPasswordRequest *request =
       [[FIRVerifyPasswordRequest alloc] initWithEmail:email
                                              password:password
@@ -591,6 +637,40 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
                                            callback:completion];
 }
 
+/** @fn internalSignInWithEmail:link:completion:
+    @brief Signs in using an email and email sign-in link.
+    @param email The user's email address.
+    @param link The email sign-in link.
+    @param callback A block which is invoked when the sign in finishes (or is cancelled.) Invoked
+        asynchronously on the global auth work queue in the future.
+ */
+- (void)internalSignInWithEmail:(nonnull NSString *)email
+                           link:(nonnull NSString *)link
+                       callback:(nullable FIRAuthResultCallback)callback {
+  NSURLComponents *urlComponents = [NSURLComponents componentsWithString:link];
+  NSDictionary<NSString *, NSString *> *queryItems = FIRAuthParseURL(urlComponents.query);
+  NSString *actionCode = queryItems[@"oobCode"];
+
+  FIREmailLinkSignInRequest *request =
+      [[FIREmailLinkSignInRequest alloc] initWithEmail:email
+                                               oobCode:actionCode
+                                  requestConfiguration:_requestConfiguration];
+
+  [FIRAuthBackend emailLinkSignin:request
+                         callback:^(FIREmailLinkSignInResponse *_Nullable response,
+                                    NSError *_Nullable error) {
+    if (error) {
+      callback(nil, error);
+      return;
+    }
+    [self completeSignInWithAccessToken:response.IDToken
+              accessTokenExpirationDate:response.approximateExpirationDate
+                           refreshToken:response.refreshToken
+                              anonymous:NO
+                               callback:callback];
+  }];
+}
+
 - (void)signInWithCredential:(FIRAuthCredential *)credential
                   completion:(FIRAuthResultCallback)completion {
   dispatch_async(FIRAuthGlobalWorkQueue(), ^{
@@ -628,24 +708,31 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
     // Special case for email/password credentials
     FIREmailPasswordAuthCredential *emailPasswordCredential =
         (FIREmailPasswordAuthCredential *)credential;
-    [self signInWithEmail:emailPasswordCredential.email
-                 password:emailPasswordCredential.password
-                 callback:^(FIRUser *_Nullable user, NSError *_Nullable error) {
+    FIRAuthResultCallback completeEmailSignIn = ^(FIRUser *user, NSError *error) {
       if (callback) {
         if (error) {
           callback(nil, error);
           return;
         }
-        FIRAdditionalUserInfo *additionalUserInfo =
-            [[FIRAdditionalUserInfo alloc] initWithProviderID:FIREmailAuthProviderID
-                                                      profile:nil
-                                                     username:nil
-                                                    isNewUser:NO];
+    FIRAdditionalUserInfo *additionalUserInfo =
+        [[FIRAdditionalUserInfo alloc] initWithProviderID:FIREmailAuthProviderID
+                                                  profile:nil
+                                                 username:nil
+                                                isNewUser:NO];
         FIRAuthDataResult *result = [[FIRAuthDataResult alloc] initWithUser:user
                                                          additionalUserInfo:additionalUserInfo];
-        callback(result, nil);
+        callback(result, error);
       }
-    }];
+    };
+    if (emailPasswordCredential.link) {
+      [self internalSignInWithEmail:emailPasswordCredential.email
+                               link:emailPasswordCredential.link
+                           callback:completeEmailSignIn];
+    } else {
+      [self signInWithEmail:emailPasswordCredential.email
+                   password:emailPasswordCredential.password
+                   callback:completeEmailSignIn];
+    }
     return;
   }
 
@@ -1013,6 +1100,31 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   });
 }
 
+- (void)sendSignInLinkToEmail:(nonnull NSString *)email
+           actionCodeSettings:(nonnull FIRActionCodeSettings *)actionCodeSettings
+                   completion:(nullable FIRSendSignInLinkToEmailCallback)completion {
+  dispatch_async(FIRAuthGlobalWorkQueue(), ^{
+    if (!email) {
+      [FIRAuthExceptionUtils raiseInvalidParameterExceptionWithReason:
+          kMissingEmailInvalidParameterExceptionReason];
+    }
+    FIRGetOOBConfirmationCodeRequest *request =
+        [FIRGetOOBConfirmationCodeRequest signInWithEmailLinkRequest:email
+                                                  actionCodeSettings:actionCodeSettings
+                                                requestConfiguration:_requestConfiguration];
+    [FIRAuthBackend getOOBConfirmationCode:request
+                                  callback:^(FIRGetOOBConfirmationCodeResponse *_Nullable response,
+                                             NSError *_Nullable error) {
+      if (completion) {
+        dispatch_async(dispatch_get_main_queue(), ^{
+          completion(error);
+        });
+      }
+    }];
+  });
+}
+
+
 - (BOOL)signOut:(NSError *_Nullable __autoreleasing *_Nullable)error {
   __block BOOL result = YES;
   dispatch_sync(FIRAuthGlobalWorkQueue(), ^{
@@ -1031,6 +1143,50 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   return [self updateCurrentUser:nil byForce:YES savingToDisk:YES error:error];
 }
 
+- (BOOL)isSignInWithEmailLink:(NSString *)link {
+  if (link.length == 0) {
+    return NO;
+  }
+  NSURLComponents *urlComponents = [NSURLComponents componentsWithString:link];
+  if (!urlComponents.query) {
+    return NO;
+  }
+  NSDictionary<NSString *, NSString *> *queryItems = FIRAuthParseURL(urlComponents.query);
+
+  NSString *actionCode = queryItems[@"oobCode"];
+  NSString *mode = queryItems[@"mode"];
+
+  if (actionCode && [mode isEqualToString:@"signIn"]) {
+    return YES;
+  }
+  return NO;
+}
+
+/** @fn FIRAuthParseURL:NSString
+    @brief Parses an incoming URL into all available query items.
+    @param urlString The url to be parsed.
+    @return A dictionary of available query items in the target URL.
+ */
+static NSDictionary<NSString *, NSString *> *FIRAuthParseURL(NSString *urlString) {
+  NSString *linkURL = [NSURLComponents componentsWithString:urlString].query;
+  NSArray<NSString *> *URLComponents = [linkURL componentsSeparatedByString:@"&"];
+  NSMutableDictionary<NSString *, NSString *> *queryItems =
+      [[NSMutableDictionary alloc] initWithCapacity:URLComponents.count];
+  for (NSString *component in URLComponents) {
+    NSRange equalRange = [component rangeOfString:@"="];
+    if (equalRange.location != NSNotFound) {
+      NSString *queryItemKey =
+          [[component substringToIndex:equalRange.location] stringByRemovingPercentEncoding];
+      NSString *queryItemValue =
+          [[component substringFromIndex:equalRange.location + 1] stringByRemovingPercentEncoding];
+      if (queryItemKey && queryItemValue) {
+        queryItems[queryItemKey] = queryItemValue;
+      }
+    }
+  }
+  return queryItems;
+}
+
 - (FIRAuthStateDidChangeListenerHandle)addAuthStateDidChangeListener:
     (FIRAuthStateDidChangeListenerBlock)listener {
   __block BOOL firstInvocation = YES;
diff --git a/Firebase/Auth/Source/Public/FIRAuth.h b/Firebase/Auth/Source/Public/FIRAuth.h
index f18a3d0..c985658 100644
--- a/Firebase/Auth/Source/Public/FIRAuth.h
+++ b/Firebase/Auth/Source/Public/FIRAuth.h
@@ -114,6 +114,14 @@ typedef void (^FIRProviderQueryCallback)(NSArray<NSString *> *_Nullable provider
                                          NSError *_Nullable error)
     NS_SWIFT_NAME(ProviderQueryCallback);
 
+/** @typedef FIRSignInMethodQueryCallback
+    @brief The type of block invoked when a list of sign-in methods for a given email address is
+        requested.
+ */
+typedef void (^FIRSignInMethodQueryCallback)(NSArray<NSString *> *_Nullable,
+                                             NSError *_Nullable)
+    NS_SWIFT_NAME(SignInMethodQueryCallback);
+
 /** @typedef FIRSendPasswordResetCallback
     @brief The type of block invoked when sending a password reset email.
 
@@ -123,6 +131,12 @@ typedef void (^FIRProviderQueryCallback)(NSArray<NSString *> *_Nullable provider
 typedef void (^FIRSendPasswordResetCallback)(NSError *_Nullable error)
     NS_SWIFT_NAME(SendPasswordResetCallback);
 
+/** @typedef FIRSendSignInLinkToEmailCallback
+    @brief The type of block invoked when sending an email sign-in link email.
+ */
+typedef void (^FIRSendSignInLinkToEmailCallback)(NSError *_Nullable error)
+    NS_SWIFT_NAME(SendSignInLinkToEmailCallback);
+
 /** @typedef FIRConfirmPasswordResetCallback
     @brief The type of block invoked when performing a password reset.
 
@@ -190,6 +204,10 @@ typedef NS_ENUM(NSInteger, FIRActionCodeOperation) {
     /** Action code for recover email operation. */
     FIRActionCodeOperationRecoverEmail = 3,
 
+    /** Action code for email link operation. */
+    FIRActionCodeOperationEmailLink = 4,
+
+
 } NS_SWIFT_NAME(ActionCodeOperation);
 
 /**
@@ -297,6 +315,24 @@ NS_SWIFT_NAME(Auth)
 - (void)fetchProvidersForEmail:(NSString *)email
                     completion:(nullable FIRProviderQueryCallback)completion;
 
+/** @fn fetchSignInMethodsForEmail:completion:
+    @brief Fetches the list of all sign-in methods previously used for the provided email address.
+
+    @param email The email address for which to obtain a list of sign-in methods.
+    @param completion Optionally; a block which is invoked when the list of sign in methods for the
+        specified email address is ready or an error was encountered. Invoked asynchronously on the
+        main thread in the future.
+
+    @remarks Possible error codes:
+
+        + `FIRAuthErrorCodeInvalidEmail` - Indicates the email address is malformed.
+
+    @remarks See @c FIRAuthErrors for a list of error codes that are common to all API methods.
+ */
+
+- (void)fetchSignInMethodsForEmail:(NSString *)email
+                        completion:(nullable FIRSignInMethodQueryCallback)completion;
+
 /** @fn signInWithEmail:password:completion:
     @brief Signs in using an email address and password.
 
@@ -322,6 +358,30 @@ NS_SWIFT_NAME(Auth)
                password:(NSString *)password
              completion:(nullable FIRAuthResultCallback)completion;
 
+/** @fn signInWithEmail:link:completion:
+    @brief Signs in using an email address and email sign-in link.
+
+    @param email The user's email address.
+    @param link The email sign-in link.
+    @param completion Optionally; a block which is invoked when the sign in flow finishes, or is
+        canceled. Invoked asynchronously on the main thread in the future.
+
+    @remarks Possible error codes:
+
+        + `FIRAuthErrorCodeOperationNotAllowed` - Indicates that email and email sign-in link
+            accounts are not enabled. Enable them in the Auth section of the
+            Firebase console.
+        + `FIRAuthErrorCodeUserDisabled` - Indicates the user's account is disabled.
+        + `FIRAuthErrorCodeInvalidEmail` - Indicates the email address is invalid.
+
+
+    @remarks See `FIRAuthErrors` for a list of error codes that are common to all API methods.
+ */
+
+- (void)signInWithEmail:(NSString *)email
+                   link:(NSString *)link
+             completion:(nullable FIRAuthDataResultCallback)completion;
+
 /** @fn signInAndRetrieveDataWithEmail:password:completion:
     @brief Signs in using an email address and password.
 
@@ -654,6 +714,19 @@ NS_SWIFT_NAME(Auth)
                  actionCodeSettings:(FIRActionCodeSettings *)actionCodeSettings
                          completion:(nullable FIRSendPasswordResetCallback)completion;
 
+/** @fn sendSignInLinkToEmail:actionCodeSettings:completion:
+    @brief Sends a sign in with email link to provided email address.
+
+    @param email The email address of the user.
+    @param actionCodeSettings An @c FIRActionCodeSettings object containing settings related to
+        handling action codes.
+    @param completion Optionally; a block which is invoked when the request finishes. Invoked
+        asynchronously on the main thread in the future.
+ */
+- (void)sendSignInLinkToEmail:(NSString *)email
+           actionCodeSettings:(FIRActionCodeSettings *)actionCodeSettings
+                   completion:(nullable FIRSendSignInLinkToEmailCallback)completion;
+
 /** @fn signOut:
     @brief Signs out the current user.
 
@@ -672,6 +745,14 @@ NS_SWIFT_NAME(Auth)
  */
 - (BOOL)signOut:(NSError *_Nullable *_Nullable)error;
 
+/** @fn isSignInWithEmailLink
+    @brief Checks if link is an email sign-in link.
+
+    @param link The email sign-in link.
+    @return @YES when the link passed matches the expected format of an email sign-in link.
+ */
+- (BOOL)isSignInWithEmailLink:(NSString *)link;
+
 /** @fn addAuthStateDidChangeListener:
     @brief Registers a block as an "auth state did change" listener. To be invoked when:
 
diff --git a/Firebase/Auth/Source/Public/FIREmailAuthProvider.h b/Firebase/Auth/Source/Public/FIREmailAuthProvider.h
index 99cd018..5823911 100644
--- a/Firebase/Auth/Source/Public/FIREmailAuthProvider.h
+++ b/Firebase/Auth/Source/Public/FIREmailAuthProvider.h
@@ -51,6 +51,15 @@ typedef FIREmailAuthProvider FIREmailPasswordAuthProvider __attribute__((depreca
  */
 + (FIRAuthCredential *)credentialWithEmail:(NSString *)email password:(NSString *)password;
 
+/** @fn credentialWithEmail:Link:
+    @brief Creates an `FIRAuthCredential` for an email & link sign in.
+
+    @param email The user's email address.
+    @param link The email sign-in link.
+    @return A FIRAuthCredential containing the email & link credential.
+ */
++ (FIRAuthCredential *)credentialWithEmail:(NSString *)email link:(NSString *)link;
+
 /** @fn init
     @brief This class is not meant to be initialized.
  */
diff --git a/Firebase/Auth/Source/RPCs/FIRAuthBackend.h b/Firebase/Auth/Source/RPCs/FIRAuthBackend.h
index a82c3a7..5928e71 100644
--- a/Firebase/Auth/Source/RPCs/FIRAuthBackend.h
+++ b/Firebase/Auth/Source/RPCs/FIRAuthBackend.h
@@ -19,6 +19,8 @@
 @class FIRAuthRequestConfiguration;
 @class FIRCreateAuthURIRequest;
 @class FIRCreateAuthURIResponse;
+@class FIREmailLinkSignInRequest;
+@class FIREmailLinkSignInResponse;
 @class FIRGetAccountInfoRequest;
 @class FIRGetAccountInfoResponse;
 @class FIRGetProjectConfigRequest;
@@ -130,6 +132,16 @@ typedef void (^FIRVerifyAssertionResponseCallback)
 typedef void (^FIRVerifyPasswordResponseCallback)
     (FIRVerifyPasswordResponse *_Nullable response, NSError *_Nullable error);
 
+/** @typedef FIREmailLinkSigninResponseCallback
+    @brief The type of block used to return the result of a call to the emailLinkSignin
+        endpoint.
+    @param response The received response, if any.
+    @param error The error which occurred, if any.
+    @remarks One of response or error will be non-nil.
+ */
+typedef void (^FIREmailLinkSigninResponseCallback)
+    (FIREmailLinkSignInResponse *_Nullable response, NSError *_Nullable error);
+
 /** @typedef FIRVerifyCustomTokenResponseCallback
     @brief The type of block used to return the result of a call to the verifyCustomToken
         endpoint.
@@ -296,6 +308,15 @@ typedef void (^FIRVerifyClientResponseCallback)
 + (void)verifyPassword:(FIRVerifyPasswordRequest *)request
               callback:(FIRVerifyPasswordResponseCallback)callback;
 
+/** @fn emailLinkSignin:callback:
+    @brief Calls the emailLinkSignin endpoint, which is responsible for authenticating a
+        user through passwordless sign-in.
+    @param request The request parameters.
+    @param callback The callback.
+ */
++ (void)emailLinkSignin:(FIREmailLinkSignInRequest *)request
+               callback:(FIREmailLinkSigninResponseCallback)callback;
+
 /** @fn secureToken:callback:
     @brief Calls the token endpoint, which is responsible for performing STS token exchanges and
         token refreshes.
@@ -461,6 +482,15 @@ typedef void (^FIRVerifyClientResponseCallback)
 - (void)verifyPassword:(FIRVerifyPasswordRequest *)request
               callback:(FIRVerifyPasswordResponseCallback)callback;
 
+/** @fn emailLinkSignin:callback:
+    @brief Calls the emailLinkSignin endpoint, which is responsible for authenticating a
+        user through passwordless sign-in.
+    @param request The request parameters.
+    @param callback The callback.
+ */
+- (void)emailLinkSignin:(FIREmailLinkSignInRequest *)request
+               callback:(FIREmailLinkSigninResponseCallback)callback;
+
 /** @fn secureToken:callback:
     @brief Calls the token endpoint, which is responsible for performing STS token exchanges and
         token refreshes.
@@ -472,7 +502,7 @@ typedef void (^FIRVerifyClientResponseCallback)
 
 /** @fn getOOBConfirmationCode:callback:
     @brief Calls the getOOBConfirmationCode endpoint, which is responsible for sending email change
-        request emails, and password reset emails.
+        request emails, email sign-in link emails, and password reset emails.
     @param request The request parameters.
     @param callback The callback.
  */
diff --git a/Firebase/Auth/Source/RPCs/FIRAuthBackend.m b/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
index 6b5232b..e380e34 100644
--- a/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
+++ b/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
@@ -51,6 +51,8 @@
 #import "FIRVerifyCustomTokenResponse.h"
 #import "FIRVerifyPasswordRequest.h"
 #import "FIRVerifyPasswordResponse.h"
+#import "FIREmailLinkSignInRequest.h"
+#import "FIREmailLinkSignInResponse.h"
 #import "FIRVerifyPhoneNumberRequest.h"
 #import "FIRVerifyPhoneNumberResponse.h"
 #import <GTMSessionFetcher/GTMSessionFetcher.h>
@@ -430,6 +432,11 @@ static id<FIRAuthBackendImplementation> gBackendImplementation;
   [[self implementation] verifyPassword:request callback:callback];
 }
 
++ (void)emailLinkSignin:(FIREmailLinkSignInRequest *)request
+               callback:(FIREmailLinkSigninResponseCallback)callback {
+  [[self implementation] emailLinkSignin:request callback:callback];
+}
+
 + (void)secureToken:(FIRSecureTokenRequest *)request
            callback:(FIRSecureTokenResponseCallback)callback {
   [[self implementation] secureToken:request callback:callback];
@@ -623,6 +630,18 @@ static id<FIRAuthBackendImplementation> gBackendImplementation;
   }];
 }
 
+- (void)emailLinkSignin:(FIREmailLinkSignInRequest *)request
+               callback:(FIREmailLinkSigninResponseCallback)callback {
+  FIREmailLinkSignInResponse *response = [[FIREmailLinkSignInResponse alloc] init];
+  [self postWithRequest:request response:response callback:^(NSError *error) {
+    if (error) {
+      callback(nil, error);
+    } else {
+      callback(response, nil);
+    }
+  }];
+}
+
 - (void)secureToken:(FIRSecureTokenRequest *)request
            callback:(FIRSecureTokenResponseCallback)callback {
   FIRSecureTokenResponse *response = [[FIRSecureTokenResponse alloc] init];
diff --git a/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.h b/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.h
index 9f6cbae..8e8f7b0 100644
--- a/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.h
+++ b/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.h
@@ -51,6 +51,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, copy, readonly, nullable) NSArray<NSString *> *allProviders;
 
+/** @property signinMethods
+    @brief A list of sign-in methods available for the passed @c identifier.
+ */
+@property(nonatomic, copy, readonly, nullable) NSArray<NSString *> *signinMethods;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.m b/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.m
index 12ef97c..6f2937f 100644
--- a/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.m
+++ b/Firebase/Auth/Source/RPCs/FIRCreateAuthURIResponse.m
@@ -25,6 +25,7 @@
   _registered = [dictionary[@"registered"] boolValue];
   _forExistingProvider = [dictionary[@"forExistingProvider"] boolValue];
   _allProviders = [dictionary[@"allProviders"] copy];
+  _signinMethods = [dictionary[@"signinMethods"] copy];
   return YES;
 }
 
diff --git a/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.h b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.h
new file mode 100644
index 0000000..e1b10d8
--- /dev/null
+++ b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2017 Google
+ *
+ * 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/Foundation.h>
+
+#import "FIRAuthRPCRequest.h"
+#import "FIRIdentityToolkitRequest.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** @class FIREmailLinkSignInRequest
+    @brief Represents the parameters for the emailLinkSignin endpoint.
+ */
+@interface FIREmailLinkSignInRequest : FIRIdentityToolkitRequest <FIRAuthRPCRequest>
+
+#pragma mark - Components of "postBody"
+
+/** @property email
+    @brief The email identifier used to complete the email link sign-in.
+ */
+@property(nonatomic, copy, readonly) NSString *email;
+
+/** @property oobCode
+    @brief The OOB code used to complete the email link sign-in flow.
+ */
+@property(nonatomic, copy, readonly) NSString *oobCode;
+
+/** @property idToken
+    @brief The ID Token code potentially used to complete the email link sign-in flow.
+ */
+@property(nonatomic, copy) NSString *IDToken;
+
+/** @fn initWithEndpoint:requestConfiguration:
+    @brief Please use initWithProviderID:requestConfifuration instead.
+ */
+- (instancetype)initWithEndpoint:(NSString *)endpoint
+            requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration NS_UNAVAILABLE;
+
+/** @fn initWithProviderID:requestConfifuration
+    @brief Designated initializer.
+    @param email The email identifier used to complete hte email link sign-in flow.
+    @param oobCode The OOB code used to complete the email link sign-in flow.
+    @param requestConfiguration An object containing configurations to be added to the request.
+
+ */
+- (instancetype)initWithEmail:(NSString *)email
+                      oobCode:(NSString *)oobCode
+         requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration
+             NS_DESIGNATED_INITIALIZER;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.m b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.m
new file mode 100644
index 0000000..9787e8e
--- /dev/null
+++ b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInRequest.m
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2017 Google
+ *
+ * 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 "FIREmailLinkSignInRequest.h"
+
+/** @var kEmailLinkSigninEndpoint
+    @brief The "EmailLinkSignin" endpoint.
+ */
+static NSString *const kEmailLinkSigninEndpoint = @"emailLinkSignin";
+
+/** @var kEmailKey
+    @brief The key for the "identifier" value in the request.
+ */
+static NSString *const kEmailKey = @"email";
+
+/** @var kEmailLinkKey
+    @brief The key for the "emailLink" value in the request.
+ */
+static NSString *const kOOBCodeKey = @"oobCode";
+
+/** @var kIDTokenKey
+    @brief The key for the "IDToken" value in the request.
+ */
+static NSString *const kIDTokenKey = @"idToken";
+
+/** @var kPostBodyKey
+    @brief The key for the "postBody" value in the request.
+ */
+static NSString *const kPostBodyKey = @"postBody";
+
+@implementation FIREmailLinkSignInRequest
+
+- (instancetype)initWithEmail:(NSString *)email
+                      oobCode:(NSString *)oobCode
+         requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration {
+  self = [super initWithEndpoint:kEmailLinkSigninEndpoint
+            requestConfiguration:requestConfiguration];
+  if (self) {
+    _email = email;
+    _oobCode = oobCode;
+  }
+  return self;
+}
+
+- (nullable id)unencodedHTTPRequestBodyWithError:(NSError *_Nullable *_Nullable)error {
+  NSMutableDictionary *postBody = [@{
+    kEmailKey : _email,
+    kOOBCodeKey : _oobCode,
+  } mutableCopy];
+
+  if (_IDToken) {
+    postBody[kIDTokenKey] = _IDToken;
+  }
+  return postBody;
+}
+
+@end
diff --git a/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.h b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.h
new file mode 100644
index 0000000..df0a127
--- /dev/null
+++ b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2017 Google
+ *
+ * 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/Foundation.h>
+
+#import "FIRAuthRPCResponse.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** @class FIRVerifyAssertionResponse
+    @brief Represents the response from the emailLinkSignin endpoint.
+ */
+@interface FIREmailLinkSignInResponse : NSObject<FIRAuthRPCResponse>
+
+/** @property IDToken
+    @brief The ID token in the email link sign-in response.
+ */
+@property(nonatomic, copy, readonly) NSString *IDToken;
+
+/** @property email
+    @brief The email returned by the IdP.
+ */
+@property(nonatomic, strong, readonly, nullable) NSString *email;
+
+/** @property refreshToken
+    @brief The refreshToken returned by the server.
+ */
+@property(nonatomic, strong, readonly, nullable) NSString *refreshToken;
+
+/** @property approximateExpirationDate
+    @brief The approximate expiration date of the access token.
+ */
+@property(nonatomic, copy, readonly, nullable) NSDate *approximateExpirationDate;
+
+/** @property isNewUser
+    @brief Flag indicating that the user signing in is a new user and not a returning user.
+ */
+@property(nonatomic, assign) BOOL isNewUser;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.m b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.m
new file mode 100644
index 0000000..cd36d41
--- /dev/null
+++ b/Firebase/Auth/Source/RPCs/FIREmailLinkSignInResponse.m
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2017 Google
+ *
+ * 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 "FIREmailLinkSignInResponse.h"
+
+@implementation FIREmailLinkSignInResponse
+
+- (BOOL)setWithDictionary:(NSDictionary *)dictionary
+                    error:(NSError *_Nullable  *_Nullable)error {
+  _email = [dictionary[@"email"] copy];
+  _IDToken = [dictionary[@"idToken"] copy];
+  _isNewUser = [dictionary[@"isNewUser"] boolValue];
+  _refreshToken = [dictionary[@"refreshToken"] copy];
+  _approximateExpirationDate = [dictionary[@"expiresIn"] isKindOfClass:[NSString class]] ?
+      [NSDate dateWithTimeIntervalSinceNow:[dictionary[@"expiresIn"] doubleValue]] : nil;
+  return YES;
+}
+
+@end
diff --git a/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.h b/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.h
index abd59b4..751cfe7 100644
--- a/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.h
+++ b/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.h
@@ -36,6 +36,11 @@ typedef NS_ENUM(NSInteger, FIRGetOOBConfirmationCodeRequestType) {
       @brief Requests an email verification code.
    */
   FIRGetOOBConfirmationCodeRequestTypeVerifyEmail,
+
+  /** @var FIRGetOOBConfirmationCodeRequestTypeEmailLink
+      @brief Requests an email sign-in link.
+   */
+  FIRGetOOBConfirmationCodeRequestTypeEmailLink,
 };
 
 /** @enum FIRGetOOBConfirmationCodeRequest
@@ -91,7 +96,7 @@ typedef NS_ENUM(NSInteger, FIRGetOOBConfirmationCodeRequestType) {
  */
 @property(assign, nonatomic) BOOL handleCodeInApp;
 
-/** @fn passwordResetRequestWithEmail:APIKey:
+/** @fn passwordResetRequestWithEmail:actionCodeSettings:requestConfiguration:
     @brief Creates a password reset request.
     @param email The user's email address.
     @param actionCodeSettings An object of FIRActionCodeSettings which specifies action code
@@ -104,7 +109,7 @@ typedef NS_ENUM(NSInteger, FIRGetOOBConfirmationCodeRequestType) {
                actionCodeSettings:(nullable FIRActionCodeSettings *)actionCodeSettings
              requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration;
 
-/** @fn verifyEmailRequestWithAccessToken:APIKey:
+/** @fn verifyEmailRequestWithAccessToken:actionCodeSettings:requestConfiguration:
     @brief Creates a password reset request.
     @param accessToken The user's STS Access Token.
     @param actionCodeSettings An object of FIRActionCodeSettings which specifies action code
@@ -117,6 +122,19 @@ typedef NS_ENUM(NSInteger, FIRGetOOBConfirmationCodeRequestType) {
                    actionCodeSettings:(nullable FIRActionCodeSettings *)actionCodeSettings
                  requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration;
 
+/** @fn signInWithEmailLinkRequest:actionCodeSettings:requestConfiguration:
+    @brief Creates a sign-in with email link.
+    @param email The user's email address.
+    @param actionCodeSettings An object of FIRActionCodeSettings which specifies action code
+        settings to be applied to the email sign-in link.
+    @param requestConfiguration An object containing configurations to be added to the request.
+    @return An email sign-in link request.
+ */
++ (nullable FIRGetOOBConfirmationCodeRequest *)
+    signInWithEmailLinkRequest:(NSString *)email
+            actionCodeSettings:(nullable FIRActionCodeSettings *)actionCodeSettings
+          requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration;
+
 /** @fn init
     @brief Please use a factory method.
  */
diff --git a/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.m b/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.m
index 653eddd..438f24b 100644
--- a/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.m
+++ b/Firebase/Auth/Source/RPCs/FIRGetOOBConfirmationCodeRequest.m
@@ -79,6 +79,11 @@ static NSString *const kCanHandleCodeInAppKey = @"canHandleCodeInApp";
  */
 static NSString *const kPasswordResetRequestTypeValue = @"PASSWORD_RESET";
 
+/** @var kEmailLinkSignInTypeValue
+    @brief The value for the "EMAIL_SIGNIN" request type.
+ */
+static NSString *const kEmailLinkSignInTypeValue= @"EMAIL_SIGNIN";
+
 /** @var kVerifyEmailRequestTypeValue
     @brief The value for the "VERIFY_EMAIL" request type.
  */
@@ -116,6 +121,8 @@ static NSString *const kVerifyEmailRequestTypeValue = @"VERIFY_EMAIL";
       return kPasswordResetRequestTypeValue;
     case FIRGetOOBConfirmationCodeRequestTypeVerifyEmail:
       return kVerifyEmailRequestTypeValue;
+    case FIRGetOOBConfirmationCodeRequestTypeEmailLink:
+      return kEmailLinkSignInTypeValue;
     // No default case so that we get a compiler warning if a new value was added to the enum.
   }
 }
@@ -142,6 +149,17 @@ static NSString *const kVerifyEmailRequestTypeValue = @"VERIFY_EMAIL";
                       requestConfiguration:requestConfiguration];
 }
 
++ (FIRGetOOBConfirmationCodeRequest *)
+    signInWithEmailLinkRequest:(NSString *)email
+            actionCodeSettings:(nullable FIRActionCodeSettings *)actionCodeSettings
+          requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration {
+  return [[self alloc] initWithRequestType:FIRGetOOBConfirmationCodeRequestTypeEmailLink
+                                     email:email
+                               accessToken:nil
+                        actionCodeSettings:actionCodeSettings
+                      requestConfiguration:requestConfiguration];
+}
+
 - (nullable instancetype)initWithRequestType:(FIRGetOOBConfirmationCodeRequestType)requestType
                                        email:(nullable NSString *)email
                                  accessToken:(nullable NSString *)accessToken
@@ -180,6 +198,12 @@ static NSString *const kVerifyEmailRequestTypeValue = @"VERIFY_EMAIL";
     body[kIDTokenKey] = _accessToken;
   }
 
+  // For email sign-in link requests, we only need an email address in addition to the already
+  // required fields.
+  if (_requestType == FIRGetOOBConfirmationCodeRequestTypeEmailLink) {
+    body[kEmailKey] = _email;
+  }
+
   if (_continueURL) {
     body[kContinueURLKey] = _continueURL;
   }