Use "issuerAssignedId" as a get() call to b2c directory to check if user exists. [JAVA]

I am trying to implement get() call for checking the existing users in b2c directory, for that I am using

User user = graphClient.users("422a535b-a60d-4e5f-833e-2789b32ca04f").buildRequest().get();

This is returning the user data, however I am only able to do this because I have user_id which was issued at the time of creation of user.

User buildUserRequest = graphClient.users()
                                .buildRequest()
                                .post(createNewUser);

        return buildUserRequest.id;

I am having a bunch of users in JSON format that I am trying to migrate, the migration is working fine, JSON looking like this :

{
  "users": [
    {
      "displayName": "Sharad Dutta",
      "givenName": "",
      "surname": "",
      "extension_user_type": "user",
      "identities": [
        {
          "signInType": "emailAddress",
          "issuerAssignedId": "00bonded007@gmail.com"
        }
      ],
      "extension_timezone": "VET",
      "extension_locale": "en-GB",
      "extension_tenant": "EG12345"
    },
    {
      "displayName": "Wayne Rooney",
      "givenName": "Wayne",
      "surname": "Rooney",
      "extension_user_type": "user",
      "identities": [
        {
          "signInType": "userName",
          "issuerAssignedId": "00bonded007"
        }
      ],
      "extension_timezone": "VET",
      "extension_locale": "en-GB",
      "extension_tenant": "EG12345"
    }
  ]
}

When I am creating a user, as long as the issuerAssignedId is not existing in the active directory, it working fine. I want to handle a case where I am checking issuerAssignedid using get() request, if user exist in directory, skip it so that code will not break or will get out due to exception.

I can do this using try/catch but can I use issuerAssignedId in place of user_id to check if user is existing in the b2c, if yes, then skip for that user.

Use this:

    LinkedList<QueryOption> requestOptions = new LinkedList<>();
    requestOptions.add(new QueryOption("$filter", "identities/any(c:c/issuerAssignedId eq '00bonded007@gmail.com' and c/issuer eq 'contoso.onmicrosoft.com')"));

    IUserCollectionPage Users = graphClient.users()
            .buildRequest(requestOptions)
            .get();

Please note that you should modify the contoso.onmicrosoft.com to your Azure B2C tenant.

To answer, when we send a post() request with attributes, and return

User buildUserRequest = null;
        try {
            buildUserRequest = graphClient.users()
                    .buildRequest()
                    .post(createNewUser);
                  
        } catch (GraphServiceException gse) {
            LOG.warn("Skipping! userPrincipalName already exists | signInType : " + signInType + " & issuerAssignedId " + issuerAssignedId);
            exitFlag = true;
            LOG.info("Setting exitFlag for existing user : " + exitFlag);
        }
        
        if (exitFlag == true) {
            return null;
        } else {
            return buildUserRequest.id;
        }

This will handle any unique criteria, not just issuerAssignedId.