In my Rails app, I have a login page. After that person logs in, what is the best way for my app to continue tracking the person that has logged in. For example, if the user moves to different pages, my controllers/actions will lose track of that user unless I keep passing a variable between each page the user subsequently visits. Is there a better way of doing this? Should I be using the sessions variable?
Yes, sessions are exactly what you are looking for.
session["user_id"] = user_id
And to fetch the current user on another page (if your model is called User):
@current_user = User.find(session["user_id]")
Strongly consider a plugin to manage this.
There are several, such as restful authentication.
This gives current_user and logged_in? functionality.
来源：https://stackoverflow.com/questions/623379/rails-tracking-a-users-id