Question

我难以捕获Cognito Sign Up Error。当Cognito返回“UsernameExistsException”，“message”：“User already exists”错误时，我正在尝试提醒用户。以下是我的代码：

self.pool!.signUp(usernameTextField.text!, password: passwordTextField.text!, userAttributes: attributes,   validationData: nil).continue(successBlock: { (task:AWSTask!) in
                // needs to be async so we can ALWAYS return nil for AWSTask
                DispatchQueue.main.async {
                    if task.error != nil {  // some sort of error
                        let myerror = task.error
                        print("\(myerror)")
                        let alert = UIAlertController(title: "Sign Up Error", message: (task.error?.localizedDescription)! as String, preferredStyle: UIAlertControllerStyle.alert)
                        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil))
                        self.present(alert, animated: true, completion: nil)
                    }
                    else    {
                        let response: AWSCognitoIdentityUserPoolSignUpResponse = task.result! as AWSCognitoIdentityUserPoolSignUpResponse
                        // NSLog("AWSCognitoIdentityUserPoolSignUpResponse: \(response)")
                        self.user = response.user
                        let alert = UIAlertController(title: "Sign Up Successful", message: "", preferredStyle: UIAlertControllerStyle.alert)
                        alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: { action in self.performSegue(withIdentifier: "confrimationSegue", sender: self) }))
                        self.present(alert, animated: true, completion: nil)

                    }
                }
                return nil
            })

由于某种原因，我无法进入task.error！= nil条件语句。当我强制执行错误时，错误不会打印，并且警报操作不会显示在视图中。我是否试图用错误的功能提醒用户？我怎样才能检查cognito提供的用户名已存在错误。提前谢谢。

Answer 1

您正在使用successBlock，这意味着只有在成功执行注册时才会调用您设置的块。这就是为什么错误总是nil。

为了获得错误，您应该通过以下方式设置回调：

userPool
    .signUp(user.email, password: user.password, userAttributes: attributes, validationData: nil)
    .continue({ response in
        if let error = response.error {
           // Error ocurred
        } else {
           // No error ocurred
        })

此continue方法仅接收回调，并在发生错误时调用。

AWS Cognito：尝试警告用户错误

1 个答案: