Topic: Twitter doesn't provide email address for Rails integration

I've integrated social logins (Facebook, Twitter, etc.) with a Rails app using Devise and OAuth. The requests and callbacks all work great and users are able to authenticate the app and login efficiently.

My problem is this:

With Devise, my site has the user's email address as the username. So, whenever a user logs in through a social site for the first time, a 'connection' record is stored for their account to show which social sites they've logged in with. If they don't already have an account on my site, one is created with the email address from the callback array. The connection is then stored along with the returned tokens and secrets for later use (FB posts, tweets, etc.).

Unfortunately, Twitter doesn't provide the email address. To circumvent this, I'm asking first-time users that login with Twitter to simply provide an email address so an account can be created. However, I can't figure out what to do if they already have an account on my site. I can't check if they already do since I'm not given an email address to match up. This could ultimately cause a user to have multiple accounts.

So, I'm a bit at a loss, and if anyone has any suggestions, it would be extremely helpful. Thanks! smile