Authlogic: Assuring that a user can't log in twice.

Question

Is there an easy way in Authlogic (haven't found nothing browsing the docs) to assure that a UserSession can't be created if the User already has an UserSession object?

In other words: I want to make sure that a user can't log in twice with the same credentials.

UPDATE: Check the comments on thief's answer to find the solution to this problem.

Answer 1

in your user sessions controller:

    before_filter :require_no_user, :only => [:new, :create]

in your app controller:

def require_no_user
  if current_user
    store_location
    flash[:notice] = "You must be logged out to access this page"
    redirect_to account_url
    return false
  end
end

Answer 2

To my mind a cleaner approach is to use callbacks in the UserSession class. Like, you can define a before_create callback there, and mark the model as invalid in appropriate case. Haven't tried this out myself, though. Here are the docs for the Callbacks module.

Answer 3

Sorry to rehash the question, but I'm having some trouble getting this to work in my app. I understand the logic - use a callback to check if the user's already logged in - but I can't seem to figure out how to write it.

Could someone elaborate a bit?