Intro

• Similar to the unix who command but for ruby web applications using warden for authentication.
• Gets list of users who are (most likely) logged in.

How to Use

# Assuming the authentication model is `User`

Warden::Who.list(User)
# returns list of user_ids who are currently logged in

Set Up

• The list of logged-in user ids is stored in redis.
• Then just gem install

gem install warden-who

• Set up with the initializer code (ie. in config/initializers if Rails application)

require "warden-who"

Warden::Who.set_cache(Redis.new(ENV["REDIS_URL"])

How it Works

• This gem plugs into the warden after_authentication and before_logout hooks to track users who are currently logged in.
• As such, there will be edgecases where this gem will miss such as:
  • users clearing cookies
  • users logging in/out on multiple devices