omniauth_callbacs_controller.rb

class OmniauthCallbacksController < Devise::OmniauthCallbacksController

  def ldap
    @user = User.find_for_ldap_auth(request.env['omniauth.auth'])

    if @user.persisted?
      flash[:notice] = I18n.t 'devise.omniauth_callbacks.success', :kind => 'ldap'
      @user.remember_me = true
      sign_in_and_redirect @user, :event => :authentication
    else
      flash[:notice] = I18n.t 'devise.omniauth_callbacks.failure', :kind => 'Ldap', :reason => 'User not found'
      redirect_to new_user_session_path
    end
  end

  def passthru
    render :file => "#{Rails.root}/public/404.html", :status => 404, :layout => false
  end

end

routes.rb

  devise_for :users, :controllers => { :omniauth_callbacks => "omniauth_callbacks", :sessions => "sessions"} do
    get '/users/auth/:provider' => 'omniauth_callbacks#passthru'
  end

sessions_controller.rb

class SessionsController < Devise::SessionsController

  prepend_view_path "app/views/devise"

  before_filter :unconfigure_phone, :only => [:destroy]
  after_filter :configure_phone, :only => [:create]

  private

  def configure_phone(reset = false)
    device = Device.find_by_hostname(request.env['HTTP_X_FORWARDED_FOR'])
    unless device.nil?
      AstCC.set_device(:device => device, :user => current_user, :reset => reset)
    else
      flash[:failure] = t('errors.messages.device_not_found')
    end
  end

  def unconfigure_phone
    configure_phone(true)
  end

end