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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
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Included Modules

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", "Dhaka" => "Asia/Dhaka", "Sri Jayawardenepura" => "Asia/Colombo", "Almaty" => "Asia/Almaty", "Astana" => "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: show | on GitHub 

# 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

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 223
def all
  @zones ||= zones_map.values.sort
end

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: show | on GitHub 

# 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

create(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: on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 300

find_tzinfo(name)

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 207
def find_tzinfo(name)
  TZInfo::Timezone.get(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.)

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 216
def new(name)
  self[name]
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.

ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"

Source: show | on GitHub 

# 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

us_zones()

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

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 254
def us_zones
  country_zones(:us)
end

Instance Public methods

<=>(zone)

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

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 333
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.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 342
def =~(re)
  re === name || re === MAPPING[name]
end

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 379
def at(*args)
  Time.at(*args).utc.in_time_zone(self)
end

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 327
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

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 396
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

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 363
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.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 551
def local_to_utc(time, dst = true)
  tzinfo.local_to_utc(time, dst)
end

match?(re)

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

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 348
def match?(re)
  (re == name) || (re == MAPPING[name]) ||
    ((Regexp === re) && (re.match?(name) || re.match?(MAPPING[name])))
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

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 516
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 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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 453
def parse(str, now = now())
  parts_to_time(Date._parse(str, false), now)
end

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 469
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

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 507
def strptime(str, format, now = now())
  parts_to_time(DateTime._strptime(str, format), now)
end

to_s()

Returns a textual representation of this time zone.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 354
def to_s
  "(GMT#{formatted_offset}) #{name}"
end

today()

Returns the current date in this time zone.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 521
def today
  tzinfo.now.to_date
end

tomorrow()

Returns the next date in this time zone.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 526
def tomorrow
  today + 1
end

utc_offset()

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

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 317
def utc_offset
  @utc_offset || tzinfo&.current_period&.base_utc_offset
end

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: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 542
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

yesterday()

Returns the previous date in this time zone.

Source: show | on GitHub 

# File activesupport/lib/active_support/values/time_zone.rb, line 531
def yesterday
  today - 1
end