The user accounts in my site are setup as such that they have a username which is unique as well as multiple barcode spans which are also unique. The barcode spans are an unlimited amount of text fields that are added through import when the user requests more materials (in a biological study). In the past the user has been allowed to login with the barcode or the username and of course their password. In porting this to drupal, I am looking to have them input the barcode span into an entityform field and then using rules (I am guessing), return the username and autofill (if possible) the username field in the login form -- is this possible?

Originally I was trying to allow them to login with a custom id (Is it possible to login to Drupal with a custom user field, instead of username/pass?) but that goes a little over my head in implementation.

I am new to drupal stackexchange and haven't used drupal in sometime, so am open to any suggestions or best practices on how to implement.

The user accounts in my site are setup as such that they have a username which is unique as well as multiple barcode spans which are also unique. The barcode spans are an unlimited amount of text fields that are added through import when the user requests more materials (in a biological study). In the past the user has been allowed to login with the barcode or the username and of course their password. In porting this to drupal, I am looking to have them input the barcode span into an entityform field and then using rules (I am guessing), return the username and autofill (if possible) the username field in the login form -- is this possible?

Originally I was trying to allow them to login with a custom id (Is it possible to login to Drupal with a custom user field, instead of username/pass?) but that goes a little over my head in implementation.

I am new to drupal stackexchange and haven't used drupal in sometime, so am open to any suggestions or best practices on how to implement.