Rails: In Application Controller, force login, redirect all requests except login

I'd like a simple method in my application controller that requires all users to log in before continuing to a开发者_开发百科ny part of the site. I'm using Devise for authentication.

I tried:

class ApplicationController < ActionController::Base
  ...
  unless user_signed_in?
    redirect_to login_path
  end
  ...
end

This successfully redirects everyone, but the problem is it also prevents the post request necessary to create a new user session.

So my question is, how would you go about blocking all requests except for the login view and the post request for logging in?

---

Using Devise this is easy. You just need to add before_filter :authenticate_user! to your ApplicationController.

This is all spelled out in the Devise wiki - https://github.com/plataformatec/devise

Note that in Rails 4.2+, before_action :authenticate_user! is preferred.