Rails application variable life cycle question

Question

Assume that I have a global variable user in application....like this:

  # GET /users.xml
  def index
    @users = User.all

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @users }
    end
  end    

Is that mean every request, a new @user is created? If every request , an object is created, when will it destroyed? Also, if vistorA go to the web site, a @userA is created, and vistorB go to the web site @userB is created. Will the vistorA have a chance to get the vistorB 's object (@userB)? Also, when will the object release? Thank you.

****Update: the @users is not the global variable, it is a instance variable. So, a question to follow up. How does the server know which @user is belong to which request? Thank you.

Answer 1

@users is not a global variable it is an instance variable . A new instance of your controller is created to handle each request so the @users for visitor A and visitor B are independent.

Answer 2

1] @users is not a Global Variable it is a instance variable.its scopre remain upto that method only.

 def index
    @some_variable= "Hello"
    other_method
    redirect_to :action=>'redirect_method'
  end

  def other_method
    #here you get @some_variable ="Hello" as you called this method in index where variable is initialise
  end

  def redirect_method
   #here you get @some_variable as you not called this method in index but redirected to this method
  end

2] for every user @users will be different as each request handle by server independently