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与多重身份验证用户合作

本文档介绍如何对注册了多重身份验证的 Identity Platform 用户执行常见任务。

更新用户的电子邮件

多重身份验证用户应始终具有经过验证的电子邮件地址。这可防止恶意操作者使用别人的电子邮件注册您的应用，然后通过添加第二重身份验证阻止真正的所有者登录。

要更新用户的电子邮件，请使用 verifyBeforeUpdateEmail() 方法。与 updateEmail() 不同，此方法要求用户在 Identity Platform 更新其电子邮件地址之前先点击验证链接。例如：

Web 版本 8

var user = firebase.auth().currentUser;
user.verifyBeforeUpdateEmail(newEmail).then(function() {
  // Email sent.
  // User must click the email link before the email is updated.
}).catch(function(error) {
  // An error happened.
});

Web 版本 9

import { getAuth, verifyBeforeUpdateEmail } from "firebase/auth";

const auth = getAuth(firebaseApp);
verifyBeforeUpdateEmail(auth.currentUser, newEmail).then(() => {
  // Email sent.
  // User must click the email link before the email is updated.
}).catch((error) => {
  // An error happened.
});

iOS

let user = Auth.auth().currentUser
user.verifyBeforeUpdateEmail(newEmail, completion: { (error) in
  if error != nil {
    // An error happened.
  }
  // Email sent.
  // User must click the email link before the email is updated.
})

Android

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
user.verifyBeforeUpdateEmail(newEmail)
   .addOnCompleteListener(
      new OnCompleteListener<Void>() {
       @Override
       public void onComplete(@NonNull Task<Void> task) {
         if (task.isSuccessful()) {
          // Email sent.
          // User must click the email link before the email is updated.
         } else {
          // An error occurred.
         }
       }
      });

默认情况下，Identity Platform 向用户发送电子邮件，并提供一个基于 Web 的简单处理程序来处理验证。您可以通过以下几种方式自定义此流程。

对验证邮件进行本地化

要对 Identity Platform 发送的电子邮件进行本地化，请先设置语言代码，然后再调用 verifyBeforeUpdateEmail()：

Web 版本 8

firebase.auth().languageCode = 'fr';

Web 版本 9

import { getAuth } from "firebase/auth";

const auth = getAuth();
auth.languageCode = 'fr';

iOS

Auth.auth().languageCode = 'fr';

Android

FirebaseAuth.getInstance().setLanguageCode("fr");

传递其他状态

您可以使用操作代码设置在验证邮件中添加其他状态，或处理来自移动应用的验证。例如：

Web 版本 8

var user = firebase.auth().currentUser;
var actionCodeSettings = {
  url: 'https://www.example.com/completeVerification?state=*****',
  iOS: {
    bundleId: 'com.example.ios'
  },
  android: {
    packageName: 'com.example.android',
    installApp: true,
    minimumVersion: '12'
  },
  handleCodeInApp: true,
  // When multiple custom dynamic link domains are defined, specify which
  // one to use.
  dynamicLinkDomain: "example.page.link"
};
user.verifyBeforeUpdateEmail(newEmail, actionCodeSettings).then(function() {
  // Email sent.
  // User must click the email link before the email is updated.
}).catch(function(error) {
  // An error happened.
});

Web 版本 9

import { getAuth, verifyBeforeUpdateEmail } from "firebase/auth";

const auth = getAuth(firebaseApp);
const user = auth.currentUser
const actionCodeSettings = {
  url: 'https://www.example.com/completeVerification?state=*****',
  iOS: {
    bundleId: 'com.example.ios'
  },
  android: {
    packageName: 'com.example.android',
    installApp: true,
    minimumVersion: '12'
  },
  handleCodeInApp: true,
  // When multiple custom dynamic link domains are defined, specify which
  // one to use.
  dynamicLinkDomain: "example.page.link"
};

  verifyBeforeUpdateEmail(auth.currentUser, newEmail, actionCodeSettings).then(() => {
    // Email sent.
    // User must click the email link before the email is updated.
  }).catch((error) => {
    // An error happened.
  })

iOS

var actionCodeSettings = ActionCodeSettings.init()
actionCodeSettings.canHandleInApp = true
let user = Auth.auth().currentUser()
actionCodeSettings.URL =
    String(format: "https://www.example.com/?email=%@", user.email)
actionCodeSettings.iOSbundleID = Bundle.main.bundleIdentifier!
actionCodeSettings.setAndroidPakageName("com.example.android",
                                         installIfNotAvailable:true,
                                         minimumVersion:"12")
// When multiple custom dynamic link domains are defined, specify which one to use.
actionCodeSettings.dynamicLinkDomain = "example.page.link"
user.sendEmailVerification(withActionCodeSettings:actionCodeSettings { error in
  if error != nil {
    // Error occurred. Inspect error.code and handle error.
    return
  }
  // Email verification sent.
})
user.verifyBeforeUpdateEmail(newEmail, actionCodeSettings, completion: { (error) in
  if error != nil {
    // An error happened.
  }
  // Email sent.
  // User must click the email link before the email is updated.
})

Android

ActionCodeSettings actionCodeSettings =
    ActionCodeSettings.newBuilder()
       .setUrl("https://www.example.com/completeVerification?state=*****")
       .setHandleCodeInApp(true)
       .setAndroidPackageName(
         "com.example.android",
         /* installIfNotAvailable= */ true,
         /* minimumVersion= */ null)
       .setIOSBundleId("com.example.ios")
       // When multiple custom dynamic link domains are defined, specify
       // which one to use.
       .setDynamicLinkDomain("example.page.link")
       .build();
FirebaseUser multiFactorUser = FirebaseAuth.getInstance().getCurrentUser();
multiFactorUser
   .verifyBeforeUpdateEmail(newEmail, actionCodeSettings)
   .addOnCompleteListener(
      new OnCompleteListener<Void>() {
       @Override
       public void onComplete(@NonNull Task<Void> task) {
         if (task.isSuccessful()) {
          // Email sent.
          // User must click the email link before the email is updated.
         } else {
          // An error occurred.
         }
       }
      });

自定义验证处理程序

您可以创建自己的处理程序来处理电子邮件验证。以下示例展示了如何在应用操作代码之前查看操作代码并检查其元数据：

Web 版本 8

var email;
firebase.auth().checkActionCode(actionCode)
  .then(function(info) {
    // Operation is equal to
    // firebase.auth.ActionCodeInfo.Operation.VERIFY_AND_CHANGE_EMAIL
    var operation = info['operation'];
    // This is the old email.
    var previousEmail = info['data']['previousEmail'];
    // This is the new email the user is changing to.
    email = info['data']['email'];
    // TODO: Display a message to the end user that the email address of the account is
    // going to be changed from `fromEmail` to `email`
    // …
    // On confirmation.
    return firebase.auth().applyActionCode(actionCode)
  }).then(function() {
    // Confirm to the end user the email was updated.
    showUI('You can now sign in with your new email: ' + email);
  })
  .catch(function(error) {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
  });

Web 版本 9

import { getAuth,  checkActionCode, applyActionCode} from "firebase/auth";

const auth = getAuth(firebaseApp);
var email;
checkActionCode(auth, actionCode)
  .then((info) => {
    // Operation is equal to
    // ActionCodeOperation.VERIFY_AND_CHANGE_EMAIL
    const operation = info['operation'];
    // This is the old email.
    const previousEmail = info['data']['previousEmail'];
    // This is the new email the user is changing to.
    email = info['data']['email'];
    // TODO: Display a message to the end user that the email address of the account is
    // going to be changed from `fromEmail` to `email`
    // …
    // On confirmation.
    return applyActionCode(auth, actionCode)
  }).then(() => {
    // Confirm to the end user the email was updated.
    showUI('You can now sign in with your new email: ' + email);
  })
  .catch((error) => {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
  });

iOS

Auth.auth().checkActionCode(actionCode) { info, error in
  if error != nil {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
    return
  }
  // This is the new email the user is changing to.
  let email = info?.email
  // This is the old email.
  let oldEmail = info?.previousEmail
  // operation is equal to
  // firebase.auth.ActionCodeInfo.Operation.VERIFY_AND_CHANGE_EMAIL
  let operation = info?.operation
  // TODO: Display a message to the end user that the email address of the account is
  // going to be changed from `fromEmail` to `email`
  // …
  // On confirmation.
  return Auth.auth().applyActionCode(actionCode)
}

Android 设备

FirebaseAuth.getInstance().checkActionCode(actionCode).addOnCompleteListener(
  new OnCompleteListener<ActionCodeResult>() {
    @Override
    public void onComplete(@NonNull Task<ActionCodeResult> task) {
      if (!task.isSuccessful()) {
        // Error occurred during confirmation. The code might have expired or the
        // link has been used before.
        return;
      }
      ActionCodeResult result = task.getResult();

      // This maps to VERIFY_AND_CHANGE_EMAIL.
      int operation = result.getOperation();

      if (operation == ActionCodeResult.VERIFY_AND_CHANGE_EMAIL) {
        ActionCodeEmailInfo actionCodeInfo =
            (ActionCodeEmailInfo) result.getInfo();

        String fromEmail = actionCodeInfo.getFromEmail();
        String email = actionCodeInfo.getEmail();
        // TODO: Display a message to the user that the email address
        // of the account is changing from `fromEmail` to `email` once
        // they confirm.
      }
    }
  });

如需了解详情，请参阅关于创建自定义电子邮件操作处理程序的 Firebase 文档。

重新验证用户身份

即使用户已经登录，您也可以在执行敏感操作之前重新对其进行身份验证，例如：

更改密码。
添加或移除新的第二重身份验证。
更新个人信息（例如地址）。
执行金融交易。
删除用户的账号。

使用电子邮件地址和密码重新验证用户身份：

网页

var resolver;
var credential = firebase.auth.EmailAuthProvider.credential(
    firebase.auth().currentUser.email, password);
firebase.auth().currentUser.reauthenticateWithCredential(credential)
  .then(function(userCredential) {
    // User successfully re-authenticated and does not require a second factor challenge.
    // ...
  })
  .catch(function(error) {
    if (error.code == 'auth/multi-factor-auth-required') {
      // Handle multi-factor authentication.
    } else {
      // Handle other errors.
    }
  });

iOS

let credential = EmailAuthProvider.credential(withEmail: email, password: password)
Auth.auth().currentUser.reauthenticate(with: credential, completion: { (result, error) in
  let authError = error as NSError?
  if (authError == nil || authError!.code != AuthErrorCode.secondFactorRequired.rawValue) {
    // User is not enrolled with a second factor or is successfully signed in.
  } else {
    // Handle multi-factor authentication.
  }
})

Android

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
AuthCredential credential = EmailAuthProvider.getCredential(user.getEmail(), password);
user.reauthenticate(credential)
   .addOnCompleteListener(
      new OnCompleteListener<AuthResult>() {
       @Override
       public void onComplete(@NonNull Task<AuthResult> task) {
         if (task.isSuccessful()) {
          // User successfully re-authenticated and does not
          // require a second factor challenge.
          // ...
          return;
         }
         if (task.getException() instanceof FirebaseAuthMultiFactorException) {
           // Handle multi-factor authentication.
         } else {
          // Handle other errors.
         }
       }
      });

使用 OAuth 提供商（如 Microsoft）重新验证用户身份：

网页

var resolver;
var user = firebase.auth().currentUser;
// Ask the user to re-authenticate with Microsoft.
var provider = new firebase.auth.OAuthProvider('microsoft.com');
// Microsoft provider allows the ability to provide a login_hint.
provider.setCustomParameters({
  login_hint: user.email
});
user.reauthenticateWithPopup(provider)
  .then(function(userCredential) {
    // User successfully re-authenticated and does not require a second factor challenge.
    // ...
  })
  .catch(function(error) {
    if (error.code == 'auth/multi-factor-auth-required') {
      // Handle multi-factor authentication.
    } else {
      // Unsupported second factor.
    } else {
      // Handle other errors.
    }
  });

iOS

var provider = OAuthProvider(providerID: "microsoft.com")
  // Replace nil with the custom class that conforms to AuthUIDelegate
  // you created in last step to use a customized web view.
  provider.getCredentialWith(nil) { credential, error in
    Auth.auth().currentUser.reauthenticate(with: credential, completion: { (result, error) in
      let authError = error as NSError?
      if (authError == nil || authError!.code != AuthErrorCode.secondFactorRequired.rawValue) {
        // User is not enrolled with a second factor or is successfully signed in.
        // ...
      } else {
        // Handle multi-factor authentication.
      }
    }
  })

Android

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
OAuthProvider.Builder provider = OAuthProvider.newBuilder("microsoft.com");
provider.addCustomParameter("login_hint", user.getEmail());
user.startActivityForReauthenticateWithProvider(/* activity= */ this, provider.build())
   .addOnCompleteListener(
      new OnCompleteListener<AuthResult>() {
       @Override
       public void onComplete(@NonNull Task<AuthResult> task) {
         if (task.isSuccessful()) {
          // User successfully re-authenticated and does not
          // require a second factor challenge.
          // ...
          return;
         }
         if (task.getException() instanceof FirebaseAuthMultiFactorException) {
           // Handle multi-factor authentication.
         } else {
          // Handle other errors such as wrong password.
         }
       }
      });

撤消最近添加的第二重身份验证

当用户注册第二重身份验证时，Identity Platform 会向其电子邮件发送通知。为了防止未经授权的活动，电子邮件中提供了一个可撤销添加第二重身份验证的选项。

Identity Platform 提供默认的电子邮件模板和处理程序，但您也可以自行构建。以下示例展示了如何创建自定义处理程序：

Web 版本 8

var obfuscatedPhoneNumber;
firebase.auth().checkActionCode(actionCode)
  .then(function(info) {
    // operation is equal to
    // firebase.auth.ActionCodeInfo.Operation.REVERT_SECOND_FACTOR_ADDITION
    var operation = info['operation'];
    // info.data.multiFactorInfo contains the data corresponding to the
    // enrolled second factor that the user is revoking.
    var multiFactorInfo = info['data']['multiFactorInfo'];
    obfuscatedPhoneNumber = multiFactorInfo['phoneNumber'];
    var displayName = multiFactorInfo['displayName'];
    // TODO: Display a message to the end user about the second factor that
    // was enrolled before the user can confirm the action to revert it.
    // ...
    // On confirmation.
    return firebase.auth().applyActionCode(actionCode)
  }).then(function() {
    // Confirm to the end user the phone number was removed from the account.
    showUI('The phone number ' + obfuscatedPhoneNumber +
         ' has been removed as a second factor from your account.' +
         ' You may also want to reset your password if you suspect' +
         ' your account was compromised.');
  })
  .catch(function(error) {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
  });

Web 版本 9

const {
  getAuth,
  checkActionCode,
  applyActionCode
} = require("firebase/auth");

const auth = getAuth(firebaseApp);
var obfuscatedPhoneNumber;
checkActionCode(auth, actionCode)
  .then((info) => {
    // Operation is equal to
    // ActionCodeOperation.REVERT_SECOND_FACTOR_ADDITION
    const operation = info['operation'];
    // info.data.multiFactorInfo contains the data corresponding to the
    // enrolled second factor that the user is revoking.
    var multiFactorInfo = info['data']['multiFactorInfo'];
    obfuscatedPhoneNumber = multiFactorInfo['phoneNumber'];
    const displayName = multiFactorInfo['displayName'];
    // TODO: Display a message to the end user about the second factor that
    // was enrolled before the user can confirm the action to revert it.
    // ...
    // On confirmation.
    return applyActionCode(auth, actionCode)
  }).then(() => {
    // Confirm to the end user the phone number was removed from the account.
    showUI('The phone number ' + obfuscatedPhoneNumber +
         ' has been removed as a second factor from your account.' +
         ' You may also want to reset your password if you suspect' +
         ' your account was compromised.');
  })
  .catch((error) => {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
  });

iOS

Auth.auth().checkActionCode(actionCode) { info, error in
  if error != nil {
    // Error occurred during confirmation. The code might have expired or the
    // link has been used before.
    return
  }
  // This is the new email the user is changing to.
  let email = info?.email
  // This is the old email.
  let oldEmail = info?.previousEmail
  // operation is equal to
  // firebase.auth.ActionCodeInfo.Operation.REVERT_SECOND_FACTOR_ADDITION
  let operation = info?.operation
  // info.multiFactorInfo contains the data corresponding to the enrolled second
  // factor that the user is revoking.
  let multiFactorInfo = info?.multiFactorInfo
  let obfuscatedPhoneNumber = (multiFactorInfo as! PhoneMultiFactorInfo).phone
  // TODO: Display a message to the end user that the email address of the account is
  // going to be changed from `fromEmail` to `email`
  // …
  // On confirmation.
  return Auth.auth().applyActionCode(actionCode)
}

Android 设备

FirebaseAuth.getInstance()
  .checkActionCode(actionCode)
  .continueWithTask(
      new Continuation<ActionCodeResult, Task<Void>>() {
        @Override
        public Task<Void> then(Task<ActionCodeResult> task) throws Exception {
          if (!task.isSuccessful()) {
            // Error occurred during confirmation. The code might have expired
            // or the link has been used before.
            return Tasks.forException(task.getException());
          }
          ActionCodeResult result = task.getResult();
          // The operation is equal to ActionCodeResult.REVERT_SECOND_FACTOR_ADDITION.
          int operation = result.getOperation();
          // The ActionCodeMultiFactorInfo contains the data corresponding to
          // the enrolled second factor that the user is revoking.
          ActionCodeMultiFactorInfo actionCodeInfo =
              (ActionCodeMultiFactorInfo) result.getInfo();
          PhoneMultiFactorInfo multiFactorInfo =
              (PhoneMultiFactorInfo) actionCodeInfo.getMultiFactorInfo();
          String obfuscatedPhoneNumber = multiFactorInfo.getPhoneNumber();
          String displayName = multiFactorInfo.getDisplayName();
          // We can now display a message to the end user about the second
          // factor that was enrolled before they confirm the action to revert
          // it.
          // ...
          // On user confirmation:
          return FirebaseAuth.getInstance().applyActionCode(actionCode);
        }
      })
  .addOnCompleteListener(
      new OnCompleteListener<Void>() {
        @Override
        public void onComplete(Task<Void> task) {
          if (task.isSuccessful()) {
            // Display a message to the user that the second factor
            // has been reverted.
          }
        }
      });

如需了解详情，请参阅关于创建自定义电子邮件操作处理程序的 Firebase 文档。

恢复第二重身份验证

Identity Platform 不提供恢复第二重身份验证的内置机制。如果用户失去对第二重身份验证的访问权限，则他们将无法登录自己的账号。为避免出现这种情况，请考虑以下做法：

警告用户如果没有第二重身份验证，将无法访问自己的账号。
强烈建议用户注册备用的第二重身份验证。
使用 Admin SDK 构建恢复流程，如果用户能够充分验证其身份（例如，上传恢复密钥或回答个人问题），便可停用多重身份验证。
向您的支持团队授予管理用户账号的权限（包括移除第二重身份验证），并为用户提供一个选项，以便他们在账号被锁定时可联系支持团队。

密码重置不会允许用户绕过多重身份验证。如果您使用 sendPasswordResetEmail() 重置用户密码，则用户在使用新密码登录时，仍需通过多重身份验证。

取消注册第二重身份验证

要取消注册某个第二重身份验证，请从用户的已注册身份验证列表中获取该项，然后调用 unenroll()。由于这是一项敏感操作，因此如果用户最近未登录，则需要先重新验证用户身份。

Web 版本 8

var options = user.multiFactor.enrolledFactors;
// Ask user to select from the enrolled options.
return user.multiFactor.unenroll(options[selectedIndex])
  .then(function() {
    // User successfully unenrolled selected factor.
  });

Web 版本 9

const multiFactorUser = multiFactor(auth.currentUser);
const options = multiFactorUser.enrolledFactors
// Ask user to select from the enrolled options.
return multiFactorUser.unenroll(options[selectedIndex])
  .then(() =>
    // User successfully unenrolled selected factor.
  });

iOS

// Ask user to select from the enrolled options.
user?.multiFactor.unenroll(with: (user?.multiFactor.enrolledFactors[selectedIndex])!,
  completion: { (error) in
    // ...
})

Android

List<MultiFactorInfo> options = user.getMultiFactor().getEnrolledFactors();
// Ask user to select from the enrolled options.
user.getMultiFactor()
   .unenroll(options.get(selectedIndex))
   .addOnCompleteListener(
      new OnCompleteListener<Void>() {
       @Override
       public void onComplete(@NonNull Task<Void> task) {
         if (task.isSuccessful()) {
          // Successfully un-enrolled.
         }
       }
      });

在某些情况下，用户可能会在移除第二重身份验证后退出登录。使用 onAuthStateChanged() 侦听此情况，并要求用户再次登录。

后续步骤

将多重身份验证添加到您的 Web、iOS 或 Android 应用中。
以编程方式管理多重身份验证用户。