Cognito用户池：如何刷新Access Token Android

Question

如何使用Cognito for Android刷新访问令牌？ 文档建议如下（ https://docs.aws.amazon.com/cognito/latest/developerguide/using-amazon-cognito-user-identity-pools-android-sdk.html ）：

// Implement authentication handler 
AuthenticationHandler handler = new AuthenticationHandler {
    @Override
    public void onSuccess(CognitoUserSession userSession) {
        // Authentication was successful, the "userSession" will have the current valid tokens
        // Time to do awesome stuff
    }

    @Override
    public void getAuthenticationDetails(final AuthenticationContinuation continuation, final String userID) {
        // User authentication details, userId and password are required to continue.
        // Use the "continuation" object to pass the user authentication details

        // After the user authentication details are available, wrap them in an AuthenticationDetails class
        // Along with userId and password, parameters for user pools for Lambda can be passed here
        // The validation parameters "validationParameters" are passed in as a Map<String, String>
        AuthenticationDetails authDetails = new AuthenticationDetails(userId, password, validationParameters);

        // Now allow the authentication to continue
        continuation.setAuthenticationDetails(authDetails);
        continuation.continueTask();
    }

    @Override
    public void getMFACode(final MultiFactorAuthenticationContinuation continuation) {
        // Multi-factor authentication is required to authenticate
        // A code was sent to the user, use the code to continue with the authentication


        // Find where the code was sent to
        String codeSentHere = continuation.getParameter()[0];

        // When the verification code is available, continue to authenticate
        continuation.setMfaCode(code);
        continuation.continueTask();
    }

    @Override
    public void authenticationChallenge(final ChallengeContinuation continuation) {
        // A custom challenge has to be solved to authenticate

        // Set the challenge responses

        // Call continueTask() method to respond to the challenge and continue with authentication.
    }

    @Override
    public void onFailure(final Exception exception) {
        // Authentication failed, probe exception for the cause

    }
};
user.getSession(handler);

这就是为什么这不起作用。 当令牌过期时，我获取Session的用户对象不再被认证。 因此，通过下面检索缓存的用户将返回null

CognitoUser user = userPool.getCurrentUser();

因为上面返回null，我尝试通过id获取用户对象

CognitoUser user = userPool.getUser(userId);

哪个工作完美，但用户未经过身份验证，并且在以下回调阶段将失败，因为userID为null

@Override
public void getAuthenticationDetails(final AuthenticationContinuation continuation, final String userID) 

只有当我在令牌过期之前尝试此调用时，这才有效，并且我可以收到新的访问令牌。 但是在令牌过期后如何做到这一点？ 任何有关这方面的帮助将不胜感激。 提前致谢

Answer 1

当您调用getSession（...） - 获取令牌时 - 如果缓存的令牌已过期，SDK将自动刷新令牌（只要刷新令牌未过期）。 如果刷新令牌也已过期，则调用getAuthenticationDetails（...），因为现在需要用户凭据（用户名，密码等）来获取新的令牌集。 无论你如何获得用户对象，即通过getCurrentUser（）或getUser（...）方法，只要有有效的缓存标记或者如果可以刷新令牌，你将获得带有getSession的有效令牌（。 ..）。

使用最新的SDK（版本2.3.1）重试。