How to verify if a user with a given email already exists in User Pool?

Do you want to request a feature or report a bug?

Question

What is the expected behavior?

Check is user exists

example

Is there such a method?

Auth.verifyIfUserExists({
    email: 'foo@bar.com'
})
.then(res => {
    // user with this email already exists
})

Because now I can find out if a user exists ONLY during signUp action. But I want to check it before I do signUp. Because if a user doesn’t exist it will be created right off the bat. And it is not what expected

Auth.signUp({
        username,
        password,
        attributes: {
        },
    })
    .then(data => console.log(data))
    .catch(err =>{
        // User exists !!
    });

Issue Analytics

State:
Created 5 years ago
Reactions:24
Comments:39 (2 by maintainers)

Top GitHub Comments

46reactions

heri16commented, Nov 7, 2018

@wzup

There is not function that does this and only this; however, I think if you use the confirmSignUp function and are using email as an alias you will get back an AliasExistsException error.

In any case I am marking this as a feature request, as it seems useful.

Thanks for your feedback.

I looked at the amplify source code.

Auth.confirmSignup() calls cognitoUser.confirmRegistration(code, forceAliasCreation) which then calls this API: https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ConfirmSignUp.html

The right way to do this (without signIn & signOut) according to the project contributors seems to be this:

const code = '000000'
Auth.confirmSignUp(username, code, {
    // If set to False, the API will throw an AliasExistsException error if the phone number/email used already exists as an alias with a different user
    forceAliasCreation: false
}).then(data => console.log(data))
  .catch( err => {
        switch ( err.code ) {
            case 'UserNotFoundException':
                return true;
            case 'NotAuthorizedException':
                return false;
            case 'AliasExistsException':
                // Email alias already exists
                return false;
            case 'CodeMismatchException':
                return false;
            case 'ExpiredCodeException':
                return false;
            default:
                return false;
        }
    } )

20reactions

tcchaucommented, Jul 5, 2018

@wzup The sign-in workaround might work just because User Pools require passwords that are 6-characters are longer so in practice, there will never be a user account whose password is ‘123’.

@haverchuck However, even if this workaround works, it’s really bad that the API doesn’t support checking the existence of a user name directly. I’ve been working with Cognito for two years and this feature already exists as a request, but hasn’t been implemented yet, along with the ability for an administrator to reset an account’s password. The combination of these two problems makes it quite difficult to build enterprise applications.