Question

I’ve got an old database with time zone formats like:

US/Eastern
Australia/Melbourne

In my new Rails app, I’m saving them as:

Eastern Time (US & Canada)
Melbourne

How can I convert the old to the new? I’ve been messing around with ActiveSupport::TimeZone, but can’t figure out the right combination to get from one to the other.

I was hoping I could create a new object, then return the newly formatted name, but it just returns the name I gave it. Example:

> tz = ActiveSupport::TimeZone.new("US/Eastern")
=> (GMT-05:00) US/Eastern
> tz.name
=> "US/Eastern"

Thanks in advance!

Answer 1

This is pretty ugly, but it’s the only way I’ve found to do it:

city = TZInfo::Timezone.get('US/Eastern').instance_eval('@linked_timezone').name
ActiveSupport::TimeZone::MAPPING.invert[city]

Edit:

For this code to work with either city or zone, you can do this:

zone = TZInfo::Timezone.get(zone_name)
city = (zone.instance_eval('@linked_timezone') || zone).name
ActiveSupport::TimeZone::MAPPING.invert[city]