如何将AWS Cognito本机用户链接到联合用户

如何解决如何将AWS Cognito本机用户链接到联合用户

当前Cognito allows将联合用户（从Google之类的外部身份提供者登录的用户）合并到本地用户（通过用户名和密码组合进行注册的用户）。

是否可以将现有的联盟用户与新的本机用户合并？

解决方法

不。您只能创建从未登录过的用户的链接。也就是说，只能在创建新用户时（在预身份验证触发器中）链接新用户。

”，这使您可以创建从现有用户帐户到 尚未用于签名的外部联合用户身份 在”。

我个人在预注册触发器中遇到了这种情况，并拒绝了自定义消息注册（“该电子邮件地址已经存在一个帐户，请使用Google登录”。）

这是我的注册前lambda，以防您觉得有用

const AWS = require("aws-sdk");
const cognito = new AWS.CognitoIdentityServiceProvider();

exports.handler = (event,context,callback) => {

  function checkForExistingUsers(event,linkToExistingUser) {

    console.log("Executing checkForExistingUsers");

    var params = {
      UserPoolId: event.userPoolId,AttributesToGet: ['sub','email'],Filter: "email = \"" + event.request.userAttributes.email + "\""
    };

    return new Promise((resolve,reject) =>
      cognito.listUsers(params,(err,result) => {
        if (err) {
          reject(err);
          return;
        }
        if (result && result.Users && result.Users[0] && result.Users[0].Username && linkToExistingUser) {
          console.log("Found existing users: ",result.Users);
          if (result.Users.length > 1){
            result.Users.sort((a,b) => (a.UserCreateDate > b.UserCreateDate) ? 1 : -1);
            console.log("Found more than one existing users. Ordered by createdDate: ",result.Users);
          }
          linkUser(result.Users[0].Username,event).then(result => {
              resolve(result);
            })
            .catch(error => {
              reject(err);
              return;
            });
        } else {
          resolve(result);
        }

      })
    );

  }

  function linkUser(sub,event) {
    console.log("Linking user accounts with target sub: " + sub + "and event: ",event);

    //By default,assume the existing account is a Cognito username/password
    var destinationProvider = "Cognito";
    var destinationSub = sub;
    //If the existing user is in fact an external user (Xero etc),override the the provider
    if (sub.includes("_")) {
      destinationProvider = sub.split("_")[0];
      destinationSub = sub.split("_")[1];
    }
    var params = {
      DestinationUser: {
        ProviderAttributeValue: destinationSub,ProviderName: destinationProvider
      },SourceUser: {
        ProviderAttributeName: 'Cognito_Subject',ProviderAttributeValue: event.userName.split("_")[1],ProviderName: event.userName.split("_")[0]
      },UserPoolId: event.userPoolId
    };
    console.log("Parameters for adminLinkProviderForUser: ",params);
    return new Promise((resolve,reject) =>
      cognito.adminLinkProviderForUser(params,result) => {
        if (err) {
          console.log("Error encountered whilst linking users: ",err);
          reject(err);
          return;
        }
        console.log("Successfully linked users.");
        resolve(result);
      })
    );
  }

  console.log(JSON.stringify(event));

  if (event.triggerSource == "PreSignUp_SignUp" || event.triggerSource == "PreSignUp_AdminCreateUser") {

    checkForExistingUsers(event,false).then(result => {
        if (result != null && result.Users != null && result.Users[0] != null) {
          console.log("Found at least one existing account with that email address: ",result);
          console.log("Rejecting sign-up");
          //prevent sign-up
          callback("An external provider account alreadys exists for that email address",null);
        } else {
          //proceed with sign-up
          callback(null,event);
        }
      })
      .catch(error => {
        console.log("Error checking for existing users: ",error);
        //proceed with sign-up
        callback(null,event);
      });

  }

  if (event.triggerSource == "PreSignUp_ExternalProvider") {

    checkForExistingUsers(event,true).then(result => {
        console.log("Completed looking up users and linking them: ",result);
        callback(null,event);
      })
      .catch(error => {
        console.log("Error checking for existing users: ",event);
      });

  }

};