application_controller.rb

class ApplicationController < ActionController::Base
  # protect_from_forgery
  before_filter :authenticate_user_from_token!
  before_filter :authenticate_user! #for classic Devise authentication
  
  def authenticate_user_from_token!
    access_token = params[:access_token].presence
    if access_token
      user = User.find_by_authentication_token(access_token.to_s)
      
      if user
        sign_in user, store: false
      else
        render :json => {:success => false, :message => "Authentication error"}, :status => 401
      end
    end
  end
end