R Bates authentication with authorize in application controller - ruby-on-rails

Question

I am rolling R Bates authentication from scratch from here, and I'm wanting to put the call to the authorize method in the application controller. Basically I want the entire app locked down. Here is the app controller...
class ApplicationController < ActionController::Base
before_filter :authorize
# Prevent CSRF attacks by raising an exception.
# For APIs, you may want to use :null_session instead.
protect_from_forgery with: :exception
private
def current_user
#current_user ||= User.find(session[:user_id]) if session[:user_id]
end
helper_method :current_user
def authorize
redirect_to login_url, alert: "Not authorized" if current_user.nil?
end
end
But the probably is I'm getting an infinite loop in my URL call. How should I hand this?
sessions controller
class SessionsController < ApplicationController
def new
end
def create
user = User.find_by_email(params[:email])
if user && user.authenticate(params[:password])
session[:user_id] = user.id
redirect_to root_url, notice: "Logged in!"
else
flash.now.alert = "Email or password is invalid"
render "new"
end
end
def destroy
session[:user_id] = nil
redirect_to root_url, notice: "Logged out!"
end
end

Answer 1

You can skip before_filter (like in #vee answer) for some actions of SessionsController:
skip_before_filter :authorize, only: [:new, :create]
Alternatively you can modify authorize method to avoid redirects in some cases:
def authorize
return if skip_authorization?("#{controller_name}##{action_name}")
redirect_to login_url, alert: "Not authorized" if current_user.nil?
end
def skip_authorization?(location)
%w(sessions#new sessions#create).include?(location)
end

Answer 2

The loop is because of the redirect_to login_url....
You should skip the authorize filter in controller that has the login action defined as:
class SessionsController < ApplicationController
skip_before_filter :authorize, only: :login
def login
...
end
...
end
Or to skip authorize filter for all actions, use skip_before_filter :authenticate without the only option.