module ActionController::HttpAuthentication::Token

Returns nil if no token is found.
Returns the return value of `&login_procedure` if a token is found.

authenticate(controller) { |token, options| ... }
take 2 arguments:
login_procedure - Proc to call if a token is present. The Proc should
controller - ActionController::Base instance for the current request.

the present token and options.
If token Authorization header is present, call the login procedure with

def authenticate(controller, &login_procedure)
  token, options = token_and_options(controller.request)
  if !token.blank?
    login_procedure.call(token, options)
  end
end