Retrieving the Current User Filter

[skrolikowski]

Hey all -

One thing I find confusing about Ruby is all the variables I have to keep track of. Now I'm reading about private and protected method filters and am about to pull out my hair. Now that I got that out of the way, here's my question/concern I found in reading chapter 8 (beginning on page 250 "Managing User Logins"):

Okay, first of all I have my defined my login method within the account_controller.rb script:

def login
  if request.post?
    @current_user = User.find_by_login_and_password(
      params[:login], params[:password])
     unless @current_user.nil?
       session[:user_id] = @current_user.id
       redirect_to :controller => 'story'
     end
  end
end

Furthermore, I followed the book and created the fetch_logged_in_user protected before_filter method:

before_filter :fetch_logged_in_user
protected
def fetch_logged_in_user
  return if session[:user_id].blank?
  @current_user = User.find_by_id(session[:user_id])
end

Once a user logs in, the instance variable @current_user is used to hold the current user's record (within the def login method) and then stores the id of the current user withing a session (session[:user_id]). Since the before_filter :fetch_logged_in_user is executed on every page, why are we using @current_user (overwriting the @current_user instance variable we used in the def login method) to store the user's record?

Maybe this isn't that serious of a question, but for some reason it's bothering me. Why did the author use the same instance variable name for both the def login method and the before_filter?

[Fenrir2]

Why not? If the user isn't logged in the @current_user variable should be blank:

  return if session[:user_id].blank?

So the login method doesn't overwrite the variable because it isn't set yet.

[skrolikowski]

Maybe my point isn't that serious, but I tried the def login method like so:

def login
  if request.post?
    @current_user1 = User.find_by_login_and_password(
      params[:login], params[:password])
     unless @current_user1.nil?
       session[:user_id] = @current_user1.id
       redirect_to :controller => 'story'
     end
  end
end

Changing the @current_user instance variable to @current_user1 and nothing changed. I was just wondering why the author would choose to use the same name for a variable...

[Fenrir2]

I think the code is clearer this way. The variable contain the same kind of object in both methods.

If I define these prodecures:

def double(number)
  number * 2
end

def halve(number)
  number / 2
end

It is strange that I used the same variable for both procedures?

[skrolikowski]

Okay, I understand.
Plus just having one instance variable @current_user takes less memory than using two (@current_user and @current_user1).

Thanks Fenrir2