File: README.rdoc

session_countdown

A Ruby on Rails plugin that puts a countdown timer on the session object.

  session.countdown_start(30.minutes)
  session.countdown_running? # => true
  session.countdown_expire
  session.countdown_running? # => false
  session.countdown_expired? # => true
  session.countdown_restart
  session.countdown_running? # => true

But why?!?

Sometimes I need to build my own custom rails authentication systems rather than use plugins such as Authlogic, Devise or restful_authentication.

There is always a "timer" in my custom authentication contraptions, and there is always a session object lurking when I‘m dealing with authentication stuff, so why not combine the two?

API

Note that countdown_expire(), countdown_restart() and countdown_count() will throw a NoCountdown exception if called on a non-existent countdown timer.

Start a countdown timer

   session.countdown_start(seconds, name = :default)

You can have multiple countdown timers if you name them. The default countdown timer is named "default".

Check if a countdown timer exists and is currently running

   session.countdown_running?(name = :default)

Expire early (i.e. logout)

   session.countdown_expire(name = :default)

Restart, using the duration supplied to countdown_start

   session.countdown_restart(name = :default)

Check if expired

   session.countdown_expired?(name = :default)

Remaining time in seconds

   session.countdown_count(name = :default)

Understanding timer running, expired, and never started

  countdown_running? == true # timer running
  countdown_expired? == true # timer expired
  countdown_running? == false && countdown_expired? == false # never ran

Synopsis

In application_controller.rb

  before_filter :authorize

  def authorize
    if session.countdown_running?
      session.countdown_restart # extend user's login
    else
      # store attempted access before rudely redirected to login screen
      session[:original_uri] = request.request_uri # rails3 use request.fullpath
      if session.countdown_expired?
        flash[:notice] = "Login Expired"
      else
        flash[:notice] = "Please login"
      end
      redirect_to :login
    end
  end

In any controller

  def login
    user = User.find_by_email(params[:email)
    if user && user.password_matches?(params[:password])
      session.countdown_start(1.hour)
      redirect_to :controller => :private
    else
      flash.now[:notice] = "Sorry, email/password wrong"
      render :index
    end

  end

  def logout
    session.countdown_expire
    flash[:notice] = "You are now logged out"
    redirect_to :index
  end

In user model

  def before_save
    if self.password_changed?
      self.salt = SecureRandom.hex(10)
      self.password = Digest::MD5.hexdigest(self.salt + self.password)
    end
  end

  def password_matches?(password_to_match)
    self.password == Digest::MD5.hexdigest(self.salt + password_to_match)
  end

Note: Remember me

If you want an "remember me" feature you need to do two things.

Set timer for far future when user checks "remember me"

  session.countdown_start(1.year)

Tell rails to serve up a persistent cookie instead of session cookie, probably in application_controller.rb

  ActionController::Base.session_options[:expire_after] = 1.year

Persistent vs session cookies

There are two types of browser cookies: ones with expiration dates and ones without. When a cookie doesnt have an expiration date it‘s a session cookie and will be deleted when the browser quits. If the cookie has an expiration date it‘s a persistent cookie (a.k.a. domain cookie) and will be valid until that date.

"Remember me" could work fine with only session cookies, provided the user never quits the browser, but users expect "remember me" to never expire their login and to persist across browser quits. It also makes sense to set a far future expiration date or the cookie will eventually expire before the login does.

Classes