问题

我想允许用户在一个字段中输入他们的用户名/密码。继续操作后，我想要运行一个检查，看看该用户是否已经存在于用户池中。如果是，就登录并继续使用应用；如果不是，则进入帐户创建流程，在该流程中，他们将被要求添加姓名、电话号码、电子邮件等。

我找不到关于如何使用AWS Cognito登录用户的文档。我应该能够在调用中传递用户名/密码，并得到一个回应，显示用户存在/用户不存在或其他内容！我是不是漏掉了什么重要的信息？

非常感谢任何帮助。我已经仔细查阅了文档...

答案1

得分: 2

要检查用户是否存在，你只需要用户名。

因此，针对你的情况，在用户输入用户名和密码后触发下面的myMethod()方法。这将会：

1. 检查用户名是否已经存在用户中。
2. 如果用户名存在，执行登录操作。
3. 如果用户名不存在，创建账户。

/**
* 假设你在用户输入用户名和密码时调用这个方法
* @param context 上下文
* @param identityProvider Cognito客户端
* @param username 用户输入的用户名
* @param password 用户输入的密码
* @return
*/
private void myMethod(Context context, AWSCognitoIdentityProvider identityProvider, String username, String password) {
    
    boolean userExists = userExists(context, identityProvider, username);
    
    if(userExists) {
        // 使用提供的密码执行登录操作
    } else {
        // 创建账户
    }
}


/**
* @param context 上下文
* @param identityProvider Cognito客户端
* @param username 用户输入的用户名
* @return 如果用户名已经被使用，返回true；否则返回false
*/
private boolean userExists(Context context, AWSCognitoIdentityProvider identityProvider, String username) {
    LambdaLogger logger = context.getLogger();

    try {
        AdminGetUserRequest getUserRequest = new AdminGetUserRequest();
        getUserRequest.setUserPoolId("cognitoPoolId");
        getUserRequest.setUsername(username);

        AdminGetUserResult getUserResult = identityProvider.adminGetUser(getUserRequest);

        return true;
    } catch (UserNotFoundException userNotFoundException) {
        logger.log("UserNotFoundException! " + userNotFoundException.toString());
        return false;
    } catch (Exception e) {
        return false;
    }
}

/**
* let's say you call this method when user enters username and password
* @param context context
* @param identityProvider cognito client
* @param username user entered username
* @param password user entered password
* @return
*/
private void myMethod(Context context, AWSCognitoIdentityProvider identityProvider, String username, String password) {
    
    boolean userExists = userExists(context, identityProvider, username);
    
    if(userExists) {
        // perform sign in with provided password
    } else {
        // create account
    }
}


/**
* @param context context
* @param identityProvider cognito client
* @param username user entered username
* @return true if username is already in use, false otherwise
*/
private boolean userExists(Context context, AWSCognitoIdentityProvider identityProvider, String username) {
    LambdaLogger logger = context.getLogger();

    try {
        AdminGetUserRequest getUserRequest = new AdminGetUserRequest();
        getUserRequest.setUserPoolId("cognitoPoolId");
        getUserRequest.setUsername(username);

        AdminGetUserResult getUserResult = identityProvider.adminGetUser(getUserRequest);

        return true;
    } catch (UserNotFoundException userNotFoundException) {
        logger.log("UserNotFoundException! " + userNotFoundException.toString());
        return false;
    } catch (Exception e) {
        return false;
    }
}

答案2

得分: 0

以下是翻译的内容：

不必每次都对 Cognito 用户池进行完整扫描，我会利用 Cognito 触发事件的能力。对于您的用例，Cognito 可以运行一个 Lambda 函数。您对「迁移用户」触发器感兴趣。基本上的情况是，当用户尝试通过 Cognito 登录您的系统且用户不存在于池中时，将触发一个触发器，让您登录用户并将其迁移到 Cognito。

传入的数据如下：

{
    "version": "1",
    "triggerSource": "UserMigration_Authentication",
    "region": "us-west-2",
    "userPoolId": "us-west-2_abcdef",
    "userName": "theusername@example.com",
    "callerContext": {
        "awsSdkVersion": "aws-sdk-unknown-unknown",
        "clientId": "yourclientid"
    },
    "request": {
        "password": "theuserpassword",
        "validationData": null,
        "userAttributes": null
    },
    "response": {
        "userAttributes": null,
        "forceAliasCreation": null,
        "finalUserStatus": null,
        "messageAction": null,
        "desiredDeliveryMediums": null
    }
}

您的 Lambda 将消耗这些数据，并最终获取用户名和密码，然后确定其是否有效。如果有效，您将在 response.userAttributes 字段中返回信息，以及是否要发送 Cognito 欢迎电子邮件 (messageAction) 和其他一些值。例如，您可以返回：

{
    "version": "1",
    "triggerSource": "UserMigration_Authentication",
    "region": "us-west-2",
    "userPoolId": "us-west-2_abcdef",
    "userName": "theusername@example.com",
    "callerContext": {
        "awsSdkVersion": "aws-sdk-unknown-unknown",
        "clientId": "yourclientid"
    },
    "request": {
        "password": "theuserpassword",
        "validationData": null,
        "userAttributes": null
    },
    "response": {
        "userAttributes": {
            "email": "theusername@example.com",
            "email_verified": "true"
        },
        "forceAliasCreation": null,
        "finalUserStatus": "CONFIRMED",
        "messageAction": "SUPPRESS",
        "desiredDeliveryMediums": null
    }
}

您的 Lambda 在 Java 中的示例代码如下：

public class MigrateUserLambda implements RequestStreamHandler {

    public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context) throws IOException {
        LambdaLogger logger = context.getLogger();

        ObjectMapper objectMapper = new ObjectMapper();
        JsonNode rootNode = objectMapper.readTree(inputStream);

        logger.log("input is " + objectMapper.writeValueAsString(rootNode));

        String email = rootNode.path("email").asText();
        String password = rootNode.path("request").path("password").asText();

        // 验证 MySQL 中的用户名和密码。如果通过...

        String triggerSource = rootNode.path("triggerSource").asText();

        if (triggerSource.equals("UserMigration_Authentication")) {
            JsonNode responseNode = rootNode.path("response");
            if (responseNode != null) {
                ((ObjectNode) responseNode).with("userAttributes").put("username", "theusername@example.com");
                ((ObjectNode) responseNode).with("userAttributes").put("email_verified", "true");
                ((ObjectNode) responseNode).put("messageAction", "SUPPRESS");
                ((ObjectNode) responseNode).put("finalUserStatus", "CONFIRMED");
            }
        }

        String output = objectMapper.writeValueAsString(rootNode);

        OutputStreamWriter writer = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
        writer.write(output);
        logger.log("sending back " + output);

        writer.close();
    }
}

{
"version": "1",
"triggerSource": "UserMigration_Authentication",
"region": "us-west-2",
"userPoolId": "us-west-2_abcdef",
"userName": "theusername@example.com",
"callerContext": {
"awsSdkVersion": "aws-sdk-unknown-unknown",
"clientId": "yourclientid"
},
"request": {
"password": "theuserpassword",
"validationData": null,
"userAttributes": null
},
"response": {
"userAttributes": null,
"forceAliasCreation": null,
"finalUserStatus": null,
"messageAction": null,
"desiredDeliveryMediums": null
}
}

{
"version": "1",
"triggerSource": "UserMigration_Authentication",
"region": "us-west-2",
"userPoolId": "us-west-2_abcdef",
"userName": "theusername@example.com",
"callerContext": {
"awsSdkVersion": "aws-sdk-unknown-unknown",
"clientId": "yourclientid"
},
"request": {
"password": "theuserpassword",
"validationData": null,
"userAttributes": null
},
"response": {
"userAttributes": { "email":"theusername@example.com",
"email_verified": "true" }
"forceAliasCreation": null,
"finalUserStatus": "CONFIRMED",
"messageAction": "SUPPRESS",
"desiredDeliveryMediums": null
}
}

public class MigrateUserLambda implements RequestStreamHandler {
public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context) throws IOException {
LambdaLogger logger = context.getLogger();
ObjectMapper objectMapper = new ObjectMapper();
JsonNode rootNode = objectMapper.readTree(inputStream);
logger.log("input is " + objectMapper.writeValueAsString(rootNode));
String email = rootNode.path("email").asText();
String password = rootNode.path("request").path("password").asText();
// verify user name and password in MySQL.  If ok...
String triggerSource = rootNode.path("triggerSource").asText();
if( triggerSource.equals("UserMigration_Authentication")) {
JsonNode responseNode = rootNode.path("response");
if (responseNode != null) {
((ObjectNode) responseNode).with("userAttributes").put("username", "theusername@example.com" );
((ObjectNode) responseNode).with("userAttributes").put("email_verified", "true" );
((ObjectNode) responseNode).put("messageAction", "SUPPRESS");
((ObjectNode) responseNode).put("finalUserStatus", "CONFIRMED");
}
}
String output = objectMapper.writeValueAsString(rootNode);
OutputStreamWriter writer = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
writer.write(output);
logger.log("sending back " + output);
writer.close();
}
}

答案3

得分: -1

public static void list() {
    AwsBasicCredentials awsCreds = AwsBasicCredentials.create(AWS_KEY,
            AWS_SECRET);

    CognitoIdentityProviderClient identityProviderClient =
            CognitoIdentityProviderClient.builder()
                    .credentialsProvider(StaticCredentialsProvider.create(awsCreds))
                    .region(Region.of(REGION))
                    .build();

    final ListUsersRequest listUsersRequest = ListUsersRequest.builder()
            .userPoolId(POOL_ID)
            .build();

    ListUsersResponse result = identityProviderClient.listUsers(listUsersRequest);

    System.out.println("Has users:" + result.hasUsers());
    result.users().stream().map(u->u.username()).forEach(System.out::println);
}

<dependency>
  <groupId>software.amazon.awssdk</groupId>
  <artifactId>aws-core</artifactId>
  <version>2.13.57</version>
</dependency>

<dependency>
  <groupId>software.amazon.awssdk</groupId>
  <artifactId>cognitoidentityprovider</artifactId>
  <version>2.13.57</version>
</dependency>

这里 是一个从Java登录用户的代码示例。

<details>
<summary>英文:</summary>
To list users you can use AWS Java SDK:
public static void list() {
AwsBasicCredentials awsCreds = AwsBasicCredentials.create(AWS_KEY,
AWS_SECRET);
CognitoIdentityProviderClient identityProviderClient =
CognitoIdentityProviderClient.builder()
.credentialsProvider(StaticCredentialsProvider.create(awsCreds))
.region(Region.of(REGION))
.build();
final ListUsersRequest listUsersRequest = ListUsersRequest.builder()
.userPoolId(POOL_ID)
.build();
ListUsersResponse result = identityProviderClient.listUsers(listUsersRequest);
System.out.println(&quot;Has users:&quot;+result.hasUsers());
result.users().stream().map(u-&gt;u.username()).forEach(System.out::println);
}
it requires next dependecies (please use latest versions):
&lt;dependency&gt;
&lt;groupId&gt;software.amazon.awssdk&lt;/groupId&gt;
&lt;artifactId&gt;aws-core&lt;/artifactId&gt;
&lt;version&gt;2.13.57&lt;/version&gt;
&lt;/dependency&gt;
&lt;dependency&gt;
&lt;groupId&gt;software.amazon.awssdk&lt;/groupId&gt;
&lt;artifactId&gt;cognitoidentityprovider&lt;/artifactId&gt;
&lt;version&gt;2.13.57&lt;/version&gt;
&lt;/dependency&gt;
[Here](https://stackoverflow.com/questions/63929294/how-to-configure-aws-user-cognito-authentication-flow-for-generating-identity-to) is a code sample of how to login user from Java. 
</details>