Ruby中的非阻塞定时事件，如JavaScript setTimeout

Question

I need to change a property on a class a few minutes after it it initialized. I attempted to use sleep inside a function but it delayed execution of everything:

active = true

def deactivate
  sleep 120
  puts 'deactivate'
  active = false
end

deactivate
puts active

What I was hoping would happen is true would log out first then two minutes later deactivate would log. However, what happens is deactivate then false log out after two minutes.

In JavaScript I would do something like:

var active = true;
setTimeout(function(){
  console.log('deactivate');
  active = false;
},120000);
console.log(active);

Answer 1

Using @ihaztehcodez's suggestion of a Thread I came up with the simple solution I was looking for:

Thread.new do
  sleep 120
  puts 'deactivate'
  active = false
end

His warning about persistence doesn't worry me in this case since I am using it for non-critical notifications. If the execution was critical then storing something in a database like @spickermann said or using a library like @km-rakibul-islam suggested would be the better solution.

Answer 2

Looks overkill for this task, but you can use delayed_job to run a task at a future time asynchronously.

  def deactivate
     puts 'deactivate'
     active = false
  end

  active = true
  handle_asynchronously :deactivate, :run_at => Proc.new { 2.minutes.from_now }

Answer 3

Well, it seems to me (When I try this code) the active and deactivate is out of order. So why not do this?:

   active = true

   def deactivate
     sleep 120
     puts 'deactivate'
     active = false
   end

   puts active
   deactivate

It works perfectly.

Answer 4

Why not just store the time until it is active?

Then there is no need to block, callback or run anything async at all. When you store active_until in a datetime column in a database model, then it allows you keep track of changes and keep the current active status even over several different requests to the app:

def active
  active_until.blank? || Time.current < active_until
end

def deactivate
  update_columns(active_until: 2.minutes.since)
end