We're building a rails app that needs to display dates (and more importantly, calculate them) in multiple timezones.

Can anyone point me towards how to work with user timezones in rails 2.3(.5 or .8)

The most inclusive article I've seen detailing how user time zones are supposed to work is here: http://wiki.rubyonrails.org/howtos/time-zones... although it is unclear when this was written or for what version of rails. Specifically it states that:

"Time.zone - The time zone that is actually used for display purposes. This may be set manually to override config.time_zone on a per-request basis."

Keys terms being "display purposes" and "per-request basis".

Locally on my machine, this is true. However on production, neither are true. Setting Time.zone persists past the end of the request (to all subsequent requests) and also affects the way AR saves to the DB (basically treating any date as if it were already in UTC even when its not), thus saving completely inappropriate values.

We run Ruby Enterprise Edition on production with passenger. If this is my problem, do we need to switch to JRuby or something else?

To illustrate the problem I put the following actions in my ApplicationController right now:

def test
p_time = Time.now.utc
s_time = Time.utc(p_time.year, p_time.month, p_time.day, p_time.hour)

logger.error "TIME.ZONE" + Time.zone.inspect
logger.error ENV['TZ'].inspect
logger.error p_time.inspect
logger.error s_time.inspect

jl = JunkLead.create!
jl.date_at = s_time

logger.error s_time.inspect
logger.error jl.date_at.inspect

jl.save!

logger.error s_time.inspect
logger.error jl.date_at.inspect


render :nothing => true, :status => 200
end


def test2
Time.zone = 'Mountain Time (US & Canada)'
logger.error "TIME.ZONE" + Time.zone.inspect
logger.error ENV['TZ'].inspect

render :nothing => true, :status => 200
end


def test3
Time.zone = 'UTC'
logger.error "TIME.ZONE" + Time.zone.inspect
logger.error ENV['TZ'].inspect


render :nothing => true, :status => 200
end

and they yield the following:

Processing ApplicationController#test (for 98.202.196.203 at 2010-12-24 22:15:50) [GET]
TIME.ZONE#<ActiveSupport::TimeZone:0x2c57a68 @tzinfo=#<TZInfo::DataTimezone: Etc/UTC>, @name="UTC", @utc_offset=0>
nil
Fri Dec 24 22:15:50 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 22:00:00 UTC +00:00
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 22:00:00 UTC +00:00
Completed in 21ms (View: 0, DB: 4) | 200 OK [http://www.dealsthatmatter.com/test]


Processing ApplicationController#test2 (for 98.202.196.203 at 2010-12-24 22:15:53) [GET]
TIME.ZONE#<ActiveSupport::TimeZone:0x2c580a8 @tzinfo=#<TZInfo::DataTimezone: America/Denver>, @name="Mountain Time (US & Canada)", @utc_offset=-25200>
nil
Completed in 143ms (View: 1, DB: 3) | 200 OK [http://www.dealsthatmatter.com/test2]


Processing ApplicationController#test (for 98.202.196.203 at 2010-12-24 22:15:59) [GET]
TIME.ZONE#<ActiveSupport::TimeZone:0x2c580a8 @tzinfo=#<TZInfo::DataTimezone: America/Denver>, @name="Mountain Time (US & Canada)", @utc_offset=-25200>
nil
Fri Dec 24 22:15:59 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 15:00:00 MST -07:00
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 15:00:00 MST -07:00
Completed in 20ms (View: 0, DB: 4) | 200 OK [http://www.dealsthatmatter.com/test]

Processing ApplicationController#test3 (for 98.202.196.203 at 2010-12-24 22:16:03) [GET]
TIME.ZONE#<ActiveSupport::TimeZone:0x2c57a68 @tzinfo=#<TZInfo::DataTimezone: Etc/UTC>, @name="UTC", @utc_offset=0>
nil
Completed in 17ms (View: 0, DB: 2) | 200 OK [http://www.dealsthatmatter.com/test3]

Processing ApplicationController#test (for 98.202.196.203 at 2010-12-24 22:16:04) [GET]
TIME.ZONE#<ActiveSupport::TimeZone:0x2c57a68 @tzinfo=#<TZInfo::DataTimezone: Etc/UTC>, @name="UTC", @utc_offset=0>
nil
Fri Dec 24 22:16:05 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 22:00:00 UTC +00:00
Fri Dec 24 22:00:00 UTC 2010
Fri, 24 Dec 2010 22:00:00 UTC +00:00
Completed in 151ms (View: 0, DB: 4) | 200 OK [http://www.dealsthatmatter.com/test]

It should be clear above that the 2nd call to /test shows Time.zone set to Mountain, even though it shouldn't.

Additionally, checking the database reveals that the test action when run after test2 saved a JunkLead record with a date of 2010-12-22 15:00:00, which is clearly wrong.