Ruby on Rails中实例变量的生命周期

Question

I am not quite clear on the life cycle of instance variables in Ruby on Rails.

1. I have an instance variable @work_days (into which I fetch and load the list of all working days in a month. The month is selected by the user from a date_select in the UI).

2. Now I have a Generate Report button which generates an excel report by calling a show method in the controller

3. Every time the user clicks the Generate Report button (and show method gets called), the value of @work_days seems to be nil and I have to initialize it every time.

Is there a way to avoid this? Why does the value of instance variable become nil every time the controller's method show is called?

Answer 1

Rails controller is instantiated per request. It means that every time you receive a request all instance variables are nil and you need to initialize them.