login.rb

# A group of actions and related helper methods dealing with login/logout.
# These are loaded from my main Sinatra app via "register Actions::Login".
# I put this file in a subdirectory called "actions".
module Actions
  module Login

    module Helpers
      def logged_in?
        if session[:user_id]
          true
        else
          false
        end
      end

      def current_user
        session[:user_id] ? User.find(session[:user_id]) : nil
      end

      def require_login!
        redirect '/login' unless logged_in?
      end

      def logout
        session[:user_id] = nil
      end
    end

    def self.registered(app)
      app.helpers Helpers

      app.get '/login' do
        Views::Login.new.to_s
      end

      app.post '/login' do
        user = ::User.authenticate(params["name"], params["password"])
        if user
          session[:user_id] = user.id
          flash("Login successful.")
          redirect '/'
        else
          session[:user_id] = nil
          flash("Login failed - Please try again.")
          redirect '/login'
        end
      end

      app.get '/logout' do
        logout
        flash("Logout successful.")
        redirect '/'
      end

    end
  end
end