Timezones in Rails

Question

I have an application where I want to allow the user to set timezones. When the user creates a reminder entry, the entry will be stored in db in UTC. But when he opens the calendar entry in the app, he should see the entry in his selected timezone. I am using Chronic but that is immaterial here.
In my ApplicationController.rb, I have the following string :

before_filter :set_user_time_zone
...
def set_user_time_zone
    Time.zone = current_user.timezone if user_signed_in?
end

After this, the entries are still saved in UTC but with the time difference. For example, I set the timezone as - "Delhi" which is +530 from UTC. When I want to save calendar entry for "Jan, 16 - 12:15 AM" - the database is populated with "2011-01-15 18:45:19 UTC" - so its 5:30 hours before the actual time I want to save.
In the UI also I keep seeing this entry instead of the the time displayed in the current user's timezone.

I want to know what should be correct way to handle this kind of timezone features in rails.

Answer 1

In the database you need to store the time in UTC and than for UI you need to convert it in the User's timezone.

Example in rails console:

Time.zone = "New Delhi"         #=> "New Delhi"

Time.now                        # => 2011-01-15 16:45:18 -0600

Time.now.in_time_zone           # => Sun, 16 Jan 2011 04:15:26 IST +05:30