Rails cookies with wrong expiring date - ruby-on-rails-3

Question

recently I've trying to set up a cookie in order to validate a session in a Rails 3.2 app.
The cookie was supposed to expire at the beginning of the next day, this way I would force users to login again (mandatory)
First I changed my app's timezone to the one I was expecting to handle:
config.time_zone = 'Caracas'
After that I created the cookie as follows:
cookies[:remember_token] = {value: user.remember_token,
expires: 1.day.from_now.beginning_of_day}
The cookie gets created without any problem but the expire date is wrong. In Chromium the date is set to today a 19:30 PM (Although my machine timezone is set accordingly to the app).
The strange thing comes when I change the definition of the cookie to:
cookies[:remember_token] = {value: user.remember_token,
expires: 1.day.from_now}
If I set to cookie only to 1 day from today then the expire date is set properly to exactly 24 hours from now.
Any ideas why beginning_of_date is not setting the date correctly?
Thanks in advance

Answer 1

It is down to the order of execution. The time zone is applied after the beginning of day is calculated. E.g. I am in UTC timezone, and I can do the following in rails console:
irb(main):019:0> 1.day.from_now.in_time_zone(Time.zone).beginning_of_day
=> Thu, 01 Nov 2012 00:00:00 UTC +00:00
irb(main):020:0> 1.day.from_now.beginning_of_day.in_time_zone(Time.zone)
=> Thu, 01 Nov 2012 00:00:00 UTC +00:00
irb(main):021:0> Time.zone.now.tomorrow.beginning_of_day
=> Thu, 01 Nov 2012 00:00:00 UTC +00:00
irb(main):022:0> 1.day.from_now.beginning_of_day.in_time_zone('Caracas')
=> Wed, 31 Oct 2012 19:30:00 VET -04:30
irb(main):023:0> 1.day.from_now.in_time_zone('Caracas').beginning_of_day
=> Thu, 01 Nov 2012 00:00:00 VET -04:30
So if you change your cookie calculation to the following it should work:
cookies[:remember_token] = {value: user.remember_token,
expires: 1.day.from_now.in_time_zone(Time.zone).beginning_of_day}