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The TimeZone class serves as a wrapper around TZInfo::Timezone instances. It allows us to do the following:

  • Limit the set of zones provided by TZInfo to a meaningful subset of 146 zones.

  • Retrieve and display zones with a friendlier name (e.g., “Eastern Time (US & Canada)” instead of “America/New_York”).

  • Lazily load TZInfo::Timezone instances only when they're needed.

  • Create ActiveSupport::TimeWithZone instances via TimeZone's local, parse, at and now methods.

If you set config.time_zone in the Rails Application, you can access this TimeZone object via Time.zone:

# application.rb:
class Application < Rails::Application
  config.time_zone = 'Eastern Time (US & Canada)'
end

Time.zone      # => #<TimeZone:0x514834...>
Time.zone.name # => "Eastern Time (US & Canada)"
Time.zone.now  # => Sun, 18 May 2008 14:30:44 EDT -04:00

The version of TZInfo bundled with Active Support only includes the definitions necessary to support the zones defined by the TimeZone class. If you need to use zones that aren't defined by TimeZone, you'll need to install the TZInfo gem (if a recent version of the gem is installed locally, this will be used instead of the bundled version.)

Namespace
Methods
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Included Modules
Constants
MAPPING = { "International Date Line West" => "Pacific/Midway", "Midway Island" => "Pacific/Midway", "American Samoa" => "Pacific/Pago_Pago", "Hawaii" => "Pacific/Honolulu", "Alaska" => "America/Juneau", "Pacific Time (US & Canada)" => "America/Los_Angeles", "Tijuana" => "America/Tijuana", "Mountain Time (US & Canada)" => "America/Denver", "Arizona" => "America/Phoenix", "Chihuahua" => "America/Chihuahua", "Mazatlan" => "America/Mazatlan", "Central Time (US & Canada)" => "America/Chicago", "Saskatchewan" => "America/Regina", "Guadalajara" => "America/Mexico_City", "Mexico City" => "America/Mexico_City", "Monterrey" => "America/Monterrey", "Central America" => "America/Guatemala", "Eastern Time (US & Canada)" => "America/New_York", "Indiana (East)" => "America/Indiana/Indianapolis", "Bogota" => "America/Bogota", "Lima" => "America/Lima", "Quito" => "America/Lima", "Atlantic Time (Canada)" => "America/Halifax", "Caracas" => "America/Caracas", "La Paz" => "America/La_Paz", "Santiago" => "America/Santiago", "Newfoundland" => "America/St_Johns", "Brasilia" => "America/Sao_Paulo", "Buenos Aires" => "America/Argentina/Buenos_Aires", "Montevideo" => "America/Montevideo", "Georgetown" => "America/Guyana", "Greenland" => "America/Godthab", "Mid-Atlantic" => "Atlantic/South_Georgia", "Azores" => "Atlantic/Azores", "Cape Verde Is." => "Atlantic/Cape_Verde", "Dublin" => "Europe/Dublin", "Edinburgh" => "Europe/London", "Lisbon" => "Europe/Lisbon", "London" => "Europe/London", "Casablanca" => "Africa/Casablanca", "Monrovia" => "Africa/Monrovia", "UTC" => "Etc/UTC", "Belgrade" => "Europe/Belgrade", "Bratislava" => "Europe/Bratislava", "Budapest" => "Europe/Budapest", "Ljubljana" => "Europe/Ljubljana", "Prague" => "Europe/Prague", "Sarajevo" => "Europe/Sarajevo", "Skopje" => "Europe/Skopje", "Warsaw" => "Europe/Warsaw", "Zagreb" => "Europe/Zagreb", "Brussels" => "Europe/Brussels", "Copenhagen" => "Europe/Copenhagen", "Madrid" => "Europe/Madrid", "Paris" => "Europe/Paris", "Amsterdam" => "Europe/Amsterdam", "Berlin" => "Europe/Berlin", "Bern" => "Europe/Berlin", "Rome" => "Europe/Rome", "Stockholm" => "Europe/Stockholm", "Vienna" => "Europe/Vienna", "West Central Africa" => "Africa/Algiers", "Bucharest" => "Europe/Bucharest", "Cairo" => "Africa/Cairo", "Helsinki" => "Europe/Helsinki", "Kyiv" => "Europe/Kiev", "Riga" => "Europe/Riga", "Sofia" => "Europe/Sofia", "Tallinn" => "Europe/Tallinn", "Vilnius" => "Europe/Vilnius", "Athens" => "Europe/Athens", "Istanbul" => "Europe/Istanbul", "Minsk" => "Europe/Minsk", "Jerusalem" => "Asia/Jerusalem", "Harare" => "Africa/Harare", "Pretoria" => "Africa/Johannesburg", "Moscow" => "Europe/Moscow", "St. Petersburg" => "Europe/Moscow", "Volgograd" => "Europe/Moscow", "Kuwait" => "Asia/Kuwait", "Riyadh" => "Asia/Riyadh", "Nairobi" => "Africa/Nairobi", "Baghdad" => "Asia/Baghdad", "Tehran" => "Asia/Tehran", "Abu Dhabi" => "Asia/Muscat", "Muscat" => "Asia/Muscat", "Baku" => "Asia/Baku", "Tbilisi" => "Asia/Tbilisi", "Yerevan" => "Asia/Yerevan", "Kabul" => "Asia/Kabul", "Ekaterinburg" => "Asia/Yekaterinburg", "Islamabad" => "Asia/Karachi", "Karachi" => "Asia/Karachi", "Tashkent" => "Asia/Tashkent", "Chennai" => "Asia/Kolkata", "Kolkata" => "Asia/Kolkata", "Mumbai" => "Asia/Kolkata", "New Delhi" => "Asia/Kolkata", "Kathmandu" => "Asia/Kathmandu", "Astana" => "Asia/Dhaka", "Dhaka" => "Asia/Dhaka", "Sri Jayawardenepura" => "Asia/Colombo", "Almaty" => "Asia/Almaty", "Novosibirsk" => "Asia/Novosibirsk", "Rangoon" => "Asia/Rangoon", "Bangkok" => "Asia/Bangkok", "Hanoi" => "Asia/Bangkok", "Jakarta" => "Asia/Jakarta", "Krasnoyarsk" => "Asia/Krasnoyarsk", "Beijing" => "Asia/Shanghai", "Chongqing" => "Asia/Chongqing", "Hong Kong" => "Asia/Hong_Kong", "Urumqi" => "Asia/Urumqi", "Kuala Lumpur" => "Asia/Kuala_Lumpur", "Singapore" => "Asia/Singapore", "Taipei" => "Asia/Taipei", "Perth" => "Australia/Perth", "Irkutsk" => "Asia/Irkutsk", "Ulaanbaatar" => "Asia/Ulaanbaatar", "Seoul" => "Asia/Seoul", "Osaka" => "Asia/Tokyo", "Sapporo" => "Asia/Tokyo", "Tokyo" => "Asia/Tokyo", "Yakutsk" => "Asia/Yakutsk", "Darwin" => "Australia/Darwin", "Adelaide" => "Australia/Adelaide", "Canberra" => "Australia/Melbourne", "Melbourne" => "Australia/Melbourne", "Sydney" => "Australia/Sydney", "Brisbane" => "Australia/Brisbane", "Hobart" => "Australia/Hobart", "Vladivostok" => "Asia/Vladivostok", "Guam" => "Pacific/Guam", "Port Moresby" => "Pacific/Port_Moresby", "Magadan" => "Asia/Magadan", "Solomon Is." => "Pacific/Guadalcanal", "New Caledonia" => "Pacific/Noumea", "Fiji" => "Pacific/Fiji", "Kamchatka" => "Asia/Kamchatka", "Marshall Is." => "Pacific/Majuro", "Auckland" => "Pacific/Auckland", "Wellington" => "Pacific/Auckland", "Nuku'alofa" => "Pacific/Tongatapu", "Tokelau Is." => "Pacific/Fakaofo", "Chatham Is." => "Pacific/Chatham", "Samoa" => "Pacific/Apia" }
 

Keys are Rails TimeZone names, values are TZInfo identifiers.

UTC_OFFSET_WITH_COLON = '%s%02d:%02d'
 
UTC_OFFSET_WITHOUT_COLON = UTC_OFFSET_WITH_COLON.tr(':', '')
 
Attributes
[R] name
[R] tzinfo
Class Public methods
[](arg)

Locate a specific time zone object. If the argument is a string, it is interpreted to mean the name of the timezone to locate. If it is a numeric value it is either the hour offset, or the second offset, of the timezone to find. (The first one with that offset will be returned.) Returns nil if no such time zone is known to the system.

# File activesupport/lib/active_support/values/time_zone.rb, line 236
def [](arg)
  case arg
    when String
    begin
      @lazy_zones_map[arg] ||= create(arg).tap(&:utc_offset)
    rescue TZInfo::InvalidTimezoneIdentifier
      nil
    end
    when Numeric, ActiveSupport::Duration
      arg *= 3600 if arg.abs <= 13
      all.find { |z| z.utc_offset == arg.to_i }
    else
      raise ArgumentError, "invalid argument to TimeZone[]: #{arg.inspect}"
  end
end
all()

Returns an array of all TimeZone objects. There are multiple TimeZone objects per time zone, in many cases, to make it easier for users to find their own time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 220
def all
  @zones ||= zones_map.values.sort
end
create(name)
Alias for: new
find_tzinfo(name)
# File activesupport/lib/active_support/values/time_zone.rb, line 204
def find_tzinfo(name)
  TZInfo::TimezoneProxy.new(MAPPING[name] || name)
end
new(name)

Returns a TimeZone instance with the given name, or nil if no such TimeZone instance exists. (This exists to support the use of this class with the composed_of macro.)

Also aliased as: create
# File activesupport/lib/active_support/values/time_zone.rb, line 213
def new(name)
  self[name]
end
new(name, utc_offset = nil, tzinfo = nil)

Create a new TimeZone object with the given name and offset. The offset is the number of seconds that this time zone is offset from UTC (GMT). Seconds were chosen as the offset unit because that is the unit that Ruby uses to represent time zone offsets (see Time#utc_offset).

# File activesupport/lib/active_support/values/time_zone.rb, line 267
def initialize(name, utc_offset = nil, tzinfo = nil)
  @name = name
  @utc_offset = utc_offset
  @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
  @current_period = nil
end
seconds_to_utc_offset(seconds, colon = true)

Assumes self represents an offset from UTC in seconds (as returned from Time#utc_offset) and turns this into an +HH:MM formatted string.

TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"
# File activesupport/lib/active_support/values/time_zone.rb, line 196
def seconds_to_utc_offset(seconds, colon = true)
  format = colon ? UTC_OFFSET_WITH_COLON : UTC_OFFSET_WITHOUT_COLON
  sign = (seconds < 0 ? '-' : '+')
  hours = seconds.abs / 3600
  minutes = (seconds.abs % 3600) / 60
  format % [sign, hours, minutes]
end
us_zones()

A convenience method for returning a collection of TimeZone objects for time zones in the USA.

# File activesupport/lib/active_support/values/time_zone.rb, line 254
def us_zones
  @us_zones ||= all.find_all { |z| z.name =~ /US|Arizona|Indiana|Hawaii|Alaska/ }
end
zones_map()
# File activesupport/lib/active_support/values/time_zone.rb, line 224
def zones_map
  @zones_map ||= begin
    MAPPING.each_key {|place| self[place]} # load all the zones
    @lazy_zones_map
  end
end
Instance Public methods
<=>(zone)

Compare this time zone to the parameter. The two are compared first on their offsets, and then by name.

# File activesupport/lib/active_support/values/time_zone.rb, line 292
def <=>(zone)
  return unless zone.respond_to? :utc_offset
  result = (utc_offset <=> zone.utc_offset)
  result = (name <=> zone.name) if result == 0
  result
end
=~(re)

Compare name and TZInfo identifier to a supplied regexp, returning true if a match is found.

# File activesupport/lib/active_support/values/time_zone.rb, line 301
def =~(re)
  re === name || re === MAPPING[name]
end
at(secs)

Method for creating new ActiveSupport::TimeWithZone instance in time zone of self from number of seconds since the Unix epoch.

Time.zone = 'Hawaii'        # => "Hawaii"
Time.utc(2000).to_f         # => 946684800.0
Time.zone.at(946684800.0)   # => Fri, 31 Dec 1999 14:00:00 HST -10:00
# File activesupport/lib/active_support/values/time_zone.rb, line 326
def at(secs)
  Time.at(secs).utc.in_time_zone(self)
end
formatted_offset(colon=true, alternate_utc_string = nil)

Returns the offset of this time zone as a formatted string, of the format “+HH:MM”.

# File activesupport/lib/active_support/values/time_zone.rb, line 286
def formatted_offset(colon=true, alternate_utc_string = nil)
  utc_offset == 0 && alternate_utc_string || self.class.seconds_to_utc_offset(utc_offset, colon)
end
local(*args)

Method for creating new ActiveSupport::TimeWithZone instance in time zone of self from given values.

Time.zone = 'Hawaii'                    # => "Hawaii"
Time.zone.local(2007, 2, 1, 15, 30, 45) # => Thu, 01 Feb 2007 15:30:45 HST -10:00
# File activesupport/lib/active_support/values/time_zone.rb, line 315
def local(*args)
  time = Time.utc(*args)
  ActiveSupport::TimeWithZone.new(nil, self, time)
end
local_to_utc(time, dst=true)

Adjust the given time to the simultaneous time in UTC. Returns a Time.utc() instance.

# File activesupport/lib/active_support/values/time_zone.rb, line 400
def local_to_utc(time, dst=true)
  tzinfo.local_to_utc(time, dst)
end
now()

Returns an ActiveSupport::TimeWithZone instance representing the current time in the time zone represented by self.

Time.zone = 'Hawaii'  # => "Hawaii"
Time.zone.now         # => Wed, 23 Jan 2008 20:24:27 HST -10:00
# File activesupport/lib/active_support/values/time_zone.rb, line 372
def now
  time_now.utc.in_time_zone(self)
end
parse(str, now=now())

Method for creating new ActiveSupport::TimeWithZone instance in time zone of self from parsed string.

Time.zone = 'Hawaii'                   # => "Hawaii"
Time.zone.parse('1999-12-31 14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00

If upper components are missing from the string, they are supplied from #now:

Time.zone.now               # => Fri, 31 Dec 1999 14:00:00 HST -10:00
Time.zone.parse('22:30:00') # => Fri, 31 Dec 1999 22:30:00 HST -10:00

However, if the date component is not provided, but any other upper components are supplied, then the day of the month defaults to 1:

Time.zone.parse('Mar 2000') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
# File activesupport/lib/active_support/values/time_zone.rb, line 346
def parse(str, now=now())
  parts = Date._parse(str, false)
  return if parts.empty?

  time = Time.new(
    parts.fetch(:year, now.year),
    parts.fetch(:mon, now.month),
    parts.fetch(:mday, parts[:year] || parts[:mon] ? 1 : now.day),
    parts.fetch(:hour, 0),
    parts.fetch(:min, 0),
    parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
    parts.fetch(:offset, 0)
  )

  if parts[:offset]
    TimeWithZone.new(time.utc, self)
  else
    TimeWithZone.new(nil, self, time)
  end
end
period_for_local(time, dst=true)

Available so that TimeZone instances respond like TZInfo::Timezone instances.

# File activesupport/lib/active_support/values/time_zone.rb, line 412
def period_for_local(time, dst=true)
  tzinfo.period_for_local(time, dst)
end
period_for_utc(time)

Available so that TimeZone instances respond like TZInfo::Timezone instances.

# File activesupport/lib/active_support/values/time_zone.rb, line 406
def period_for_utc(time)
  tzinfo.period_for_utc(time)
end
to_s()

Returns a textual representation of this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 306
def to_s
  "(GMT#{formatted_offset}) #{name}"
end
today()

Return the current date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 377
def today
  tzinfo.now.to_date
end
tomorrow()

Returns the next date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 382
def tomorrow
  today + 1
end
utc_offset()

Returns the offset of this time zone from UTC in seconds.

# File activesupport/lib/active_support/values/time_zone.rb, line 275
def utc_offset
  if @utc_offset
    @utc_offset
  else
    @current_period ||= tzinfo.current_period if tzinfo
    @current_period.utc_offset if @current_period
  end
end
utc_to_local(time)

Adjust the given time to the simultaneous time in the time zone represented by self. Returns a Time.utc() instance – if you want an ActiveSupport::TimeWithZone instance, use DateAndTime::Zones#in_time_zone instead.

# File activesupport/lib/active_support/values/time_zone.rb, line 394
def utc_to_local(time)
  tzinfo.utc_to_local(time)
end
yesterday()

Returns the previous date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 387
def yesterday
  today - 1
end