Rails-单击事件-如何处理2种Ruby方法之间的竞争情况？

Question

On my view I have a link_to element "Start Quiz!" that calls a controller method (method A) that sets a variable "Phase" and redirects the user to a new static page. In my CoffeeScript I have an event listener listening for clicks on this link_to element. The listener calls a different method (method B) on the backend that uses the "Phase" variable to do sth.

The problem: sometimes method B tries to use the "Phase" variable before it has been updated by the controller method A! Does anyone have a suggestion what the best way would be to ensure that the "Phase" variable was updated before using it for anything else?

I'm a Rails beginner and would appreciate any pointers. :)

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EDIT: "Phase" is a variable I use to track the current question of my quiz. It's not dependent on any input, but it needs increment whenever a new page is rendered (which is triggered by the button click).

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EDIT2: I've now tried to solve this by introducing an instance variable flag "is_changed" to my controller and letting the method B sleep until the flag is set to true:

#method B:
def send_answers
   until controller.index_changed?
     sleep(0.5)
   end
   ...
   do sth.
end

#method A (in controller):
def initialize
   @index_changed = false
end

def index_changed?
   @index_changed
end

def set_index_changed!
   @index_changed = false
end

def switch_to_next_question
   ...
   self.phase += 1
   if self.save
      Thread.new do
         @index_changed = true
         ActiveRecord::Base.connection.close
      end
   else
      ...
   end
end

It's not working. Method A gets stuck sleeping. How do I fix this? And is this even the right approach?

Is it a problem with the scope of my @index_changed variable? I'm trying to create an instance variable that is accessible from multiple methods within the class, but individual to each instance of this class.

Answer 1

Ok, I solved it by finding a way to call the 2 methods sequentially. I ended up eliminating the on click listener completely and calling the ActionCable backend method directly , which was possible by turning it into a class method:

class QuizDataChannel < ApplicationCable::Channel
  #method B:
  def self.send_answers #self. makes it a class method
    #...
    #do something with phase
  end
end

And in my controller:

#method A:
def switch_to_next_question
   #...
   self.phase += 1
   if self.save
      QuizDataChannel.send_answers
   else
      #...
   end
end

As you can see in the end I got rid of all of these: sleep , new threads and the index_changed flag.