Active Support Time Zone

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

Methods

Included Modules

  • Comparable

Constants

MAPPING = { "International Date Line West" => "Etc/GMT+12", "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", "Puerto Rico" => "America/Puerto_Rico", "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/Zurich", "Zurich" => "Europe/Zurich", "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", "Kaliningrad" => "Europe/Kaliningrad", "Moscow" => "Europe/Moscow", "St. Petersburg" => "Europe/Moscow", "Volgograd" => "Europe/Volgograd", "Samara" => "Europe/Samara", "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/Canberra", "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", "Srednekolymsk" => "Asia/Srednekolymsk", "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.

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.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 232
      def [](arg)
        case arg
        when self
          arg
        when String
          begin
            @lazy_zones_map[arg] ||= create(arg)
          rescue TZInfo::InvalidTimezoneIdentifier
            nil
          end
        when TZInfo::Timezone
          @lazy_zones_map[arg.name] ||= create(arg.name, nil, arg)
        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
🔎 See on GitHub

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.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 223
      def all
        @zones ||= zones_map.values.sort
      end
🔎 See on GitHub

country_zones(country_code)

A convenience method for returning a collection of TimeZone objects for time zones in the country specified by its ISO 3166-1 Alpha2 code.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 260
      def country_zones(country_code)
        code = country_code.to_s.upcase
        @country_zones[code] ||= load_country_zones(code)
      end
🔎 See on GitHub

create(name)

Alias for: new

find_tzinfo(name)

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 207
      def find_tzinfo(name)
        TZInfo::Timezone.get(MAPPING[name] || name)
      end
🔎 See on GitHub

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
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 216
      def new(name)
        self[name]
      end
🔎 See on GitHub

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).

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 303
    def initialize(name, utc_offset = nil, tzinfo = nil)
      @name = name
      @utc_offset = utc_offset
      @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
    end
🔎 See on GitHub

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.

ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 199
      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
🔎 See on GitHub

us_zones()

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 254
      def us_zones
        country_zones(:us)
      end
🔎 See on GitHub

Instance Public methods

<=>(zone)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 326
    def <=>(zone)
      return unless zone.respond_to? :utc_offset
      result = (utc_offset <=> zone.utc_offset)
      result = (name <=> zone.name) if result == 0
      result
    end
🔎 See on GitHub

=~(re)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 335
    def =~(re)
      re === name || re === MAPPING[name]
    end
🔎 See on GitHub

at(*args)

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

A second argument can be supplied to specify sub-second precision.

Time.zone = 'Hawaii'                # => "Hawaii"
Time.at(946684800, 123456.789).nsec # => 123456789
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 372
    def at(*args)
      Time.at(*args).utc.in_time_zone(self)
    end
🔎 See on GitHub

formatted_offset(colon = true, alternate_utc_string = nil)

Returns a formatted string of the offset from UTC, or an alternative string if the time zone is already UTC.

zone = ActiveSupport::TimeZone['Central Time (US & Canada)']
zone.formatted_offset        # => "-06:00"
zone.formatted_offset(false) # => "-0600"
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 320
    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
🔎 See on GitHub

iso8601(str)

Method for creating new ActiveSupport::TimeWithZone instance in time zone of self from an ISO 8601 string.

Time.zone = 'Hawaii'                     # => "Hawaii"
Time.zone.iso8601('1999-12-31T14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00

If the time components are missing then they will be set to zero.

Time.zone = 'Hawaii'            # => "Hawaii"
Time.zone.iso8601('1999-12-31') # => Fri, 31 Dec 1999 00:00:00 HST -10:00

If the string is invalid then an ArgumentError will be raised unlike parse which usually returns nil when given an invalid date string.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 389
    def iso8601(str)
      # Historically `Date._iso8601(nil)` returns `{}`, but in the `date` gem versions `3.2.1`, `3.1.2`, `3.0.2`,
      # and `2.0.1`, `Date._iso8601(nil)` raises `TypeError` https://github.com/ruby/date/issues/39
      # Future `date` releases are expected to revert back to the original behavior.
      raise ArgumentError, "invalid date" if str.nil?

      parts = Date._iso8601(str)

      year = parts.fetch(:year)

      if parts.key?(:yday)
        ordinal_date = Date.ordinal(year, parts.fetch(:yday))
        month = ordinal_date.month
        day = ordinal_date.day
      else
        month = parts.fetch(:mon)
        day = parts.fetch(:mday)
      end

      time = Time.new(
        year,
        month,
        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

    rescue Date::Error, KeyError
      raise ArgumentError, "invalid date"
    end
🔎 See on GitHub

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
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 356
    def local(*args)
      time = Time.utc(*args)
      ActiveSupport::TimeWithZone.new(nil, self, time)
    end
🔎 See on GitHub

local_to_utc(time, dst = true)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 544
    def local_to_utc(time, dst = true)
      tzinfo.local_to_utc(time, dst)
    end
🔎 See on GitHub

match?(re)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 341
    def match?(re)
      (re == name) || (re == MAPPING[name]) ||
        ((Regexp === re) && (re.match?(name) || re.match?(MAPPING[name])))
    end
🔎 See on GitHub

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
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 509
    def now
      time_now.utc.in_time_zone(self)
    end
🔎 See on GitHub

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 TimeZone#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

If the string is invalid then an ArgumentError could be raised.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 446
    def parse(str, now = now())
      parts_to_time(Date._parse(str, false), now)
    end
🔎 See on GitHub

period_for_local(time, dst = true)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 556
    def period_for_local(time, dst = true)
      tzinfo.period_for_local(time, dst) { |periods| periods.last }
    end
🔎 See on GitHub

period_for_utc(time)

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 550
    def period_for_utc(time)
      tzinfo.period_for_utc(time)
    end
🔎 See on GitHub

rfc3339(str)

Method for creating new ActiveSupport::TimeWithZone instance in time zone of self from an RFC 3339 string.

Time.zone = 'Hawaii'                     # => "Hawaii"
Time.zone.rfc3339('2000-01-01T00:00:00Z') # => Fri, 31 Dec 1999 14:00:00 HST -10:00

If the time or zone components are missing then an ArgumentError will be raised. This is much stricter than either parse or iso8601 which allow for missing components.

Time.zone = 'Hawaii'            # => "Hawaii"
Time.zone.rfc3339('1999-12-31') # => ArgumentError: invalid date
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 462
    def rfc3339(str)
      parts = Date._rfc3339(str)

      raise ArgumentError, "invalid date" if parts.empty?

      time = Time.new(
        parts.fetch(:year),
        parts.fetch(:mon),
        parts.fetch(:mday),
        parts.fetch(:hour),
        parts.fetch(:min),
        parts.fetch(:sec) + parts.fetch(:sec_fraction, 0),
        parts.fetch(:offset)
      )

      TimeWithZone.new(time.utc, self)
    end
🔎 See on GitHub

strptime(str, format, now = now())

Parses str according to format and returns an ActiveSupport::TimeWithZone.

Assumes that str is a time in the time zone self, unless format includes an explicit time zone. (This is the same behavior as parse.) In either case, the returned TimeWithZone has the timezone of self.

Time.zone = 'Hawaii'                   # => "Hawaii"
Time.zone.strptime('1999-12-31 14:00:00', '%Y-%m-%d %H:%M:%S') # => Fri, 31 Dec 1999 14:00:00 HST -10:00

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

Time.zone.now                              # => Fri, 31 Dec 1999 14:00:00 HST -10:00
Time.zone.strptime('22:30:00', '%H:%M:%S') # => 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.strptime('Mar 2000', '%b %Y') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 500
    def strptime(str, format, now = now())
      parts_to_time(DateTime._strptime(str, format), now)
    end
🔎 See on GitHub

to_s()

Returns a textual representation of this time zone.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 347
    def to_s
      "(GMT#{formatted_offset}) #{name}"
    end
🔎 See on GitHub

today()

Returns the current date in this time zone.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 514
    def today
      tzinfo.now.to_date
    end
🔎 See on GitHub

tomorrow()

Returns the next date in this time zone.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 519
    def tomorrow
      today + 1
    end
🔎 See on GitHub

utc_offset()

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

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 310
    def utc_offset
      @utc_offset || tzinfo&.current_period&.base_utc_offset
    end
🔎 See on GitHub

utc_to_local(time)

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

As of tzinfo 2, utc_to_local returns a Time with a non-zero utc_offset. See the utc_to_local_returns_utc_offset_times config for more info.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 535
    def utc_to_local(time)
      tzinfo.utc_to_local(time).yield_self do |t|
        ActiveSupport.utc_to_local_returns_utc_offset_times ?
          t : Time.utc(t.year, t.month, t.day, t.hour, t.min, t.sec, t.sec_fraction * 1_000_000)
      end
    end
🔎 See on GitHub

yesterday()

Returns the previous date in this time zone.

📝 Source code
# File activesupport/lib/active_support/values/time_zone.rb, line 524
    def yesterday
      today - 1
    end
🔎 See on GitHub