Ruby-on-rails – Time zone in RAILS

ruby-1.9.2-p180:001:0>> require'active_support /all' # included by Rails by default
# => true
ruby-1.9.2-p180:002:0>> dt = DateTime.parse "Wed, 22 Jun 2011 09:43:58 +0200"
# => Wed, 22 Jun 2011 09:43:58 +0200
ruby-1.9.2-p180:003:0>> dt.utc_offset
# => 7200 
ruby-1.9.2-p180:004:0>> dt.utc
# => Wed, 22 Jun 2011 07:43:58 +0000

ruby-1.9.2-p180 :039> u.utc.new_offset(u.offset)
=> Wed, 22 Jun 2011 09:43:58 +0500 
ruby-1.9.2-p180 :040> u
=> Wed, 22 Jun 2011 09:43:58 +0500

If I have a time string in the form of “Wed, 22 Jun 2011 09:43:58 0200” from a customer, I want to save the time zone. This is important because it is not only the absolute UTC that is important Time, and time zone.

Time.zone.parse(t) will convert the time to the zone that Time.zone is in use at the time, thus losing the source time zone.

Do I have to manually extract the time zone from the string above, or is there The idiomatic way to do this?

The DateTime field can only store’YYYY-MM-DD HH:MM:SS’ (MySQL), without time zone information.

You should store the date and time in UTC and the time zone in a different field, preferably an integer, specifying the offset from UTC (in minutes).

You You can extract the offset like this:

ruby-1.9.2-p180:001:0>> require'active_support/all' # included by Rails by default
# => true
ruby-1.9.2-p180:002:0>> dt = DateTime.parse "Wed, 22 Jun 2011 09:43:58 +0200"
# => Wed, 22 Jun 2011 09:43:58 +0200
ruby-1.9.2-p180:003:0>> dt.utc_offset
# => 7200
ruby-1.9.2-p180: 004:0>> dt.utc
# => Wed, 22 Jun 2011 07:43:58 +0000

Edit:

Practice round trip

< p>

ruby-1.9.2-p180 :039> u.utc.new_offset(u.offset)
=> Wed, 22 Jun 2011 09:43:58 +0500 
ruby-1.9.2-p180 :040> u
=> Wed, 22 Jun 2011 09:43:58 +0500