Question

I’m a little confused about the purpose of doing this:

module SessionsHelper
   def current_user=(user)
       @current_user = user
   end
end

source: http://ruby.railstutorial.org/chapters/sign-in-sign-out#code:current_user_equals

because through our controller we set @user, which has a the scope between controller, and views, so why do we need to define it explicitly?

Also, the explanation is allows for:

redirect_to current_user

how does the function current_user, know when I say redirect_to (function) im talking about @variable_path ? (in this case user_path)

Answer 1

more than 90% rails developers know that( and its now been the part of Rails Convention Over Configuration we can say)

• current_user represents User object
• current_user represents just not any user, but one who logged in

When you look at rails code, and you find @user, you need to read through a couple of lines where @user is defined, to know why it is defined, whats the purpose of it. Thats not the case with current_user, as it represents the logged in user.

About your 2nd question,

  redirect_to some_object # or any function that returns some object

when you pass any object to redirect_to, redirection happens for the url

  "/#{object.class.name.tableize}/#{object.id}"

which suppose to be a page, a ‘show’ page, detailing out object to end user

object_path or object_url make the same url