Class: ActiveSupport::TimeZone

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
activesupport/lib/active_support/values/time_zone.rb

Overview

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.)

Constant Summary collapse

MAPPING =

Keys are Rails TimeZone names, values are TZInfo identifiers.

{
  "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"
}
UTC_OFFSET_WITH_COLON = 
'%s%02d:%02d'
UTC_OFFSET_WITHOUT_COLON = 
UTC_OFFSET_WITH_COLON.sub(':', '')

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, utc_offset = nil, tzinfo = nil) ⇒ TimeZone

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).



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 207

def initialize(name, utc_offset = nil, tzinfo = nil)
  self.class.send(:require_tzinfo)

  @name = name
  @utc_offset = utc_offset
  @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
  @current_period = nil
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 200

def name
  @name
end

#tzinfo ⇒ Object (readonly)

Returns the value of attribute tzinfo



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 201

def tzinfo
  @tzinfo
end

Class Method Details

.[](arg) ⇒ Object

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.



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 377

def [](arg)
  case arg
    when String
    begin
      lazy_zones_map[arg] ||= lookup(arg).tap { |tz| tz.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 ⇒ Object

Return 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.



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 359

def all
  @zones ||= zones_map.values.sort
end

.create ⇒ Object 



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 347

alias_method :create, :new

.find_tzinfo(name) ⇒ Object 



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 342

def self.find_tzinfo(name)
  TZInfo::TimezoneProxy.new(MAPPING[name] || name)
end

.new(name) ⇒ Object

Return 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.)



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 352

def new(name)
  self[name]
end

.seconds_to_utc_offset(seconds, colon = true) ⇒ Object

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"



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 191

def self.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 ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 395

def us_zones
  @us_zones ||= all.find_all { |z| z.name =~ /US|Arizona|Indiana|Hawaii|Alaska/ }
end

.zones_map ⇒ Object 



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

def zones_map
  @zones_map ||= begin
    new_zones_names = MAPPING.keys - lazy_zones_map.keys
    new_zones       = Hash[new_zones_names.map { |place| [place, create(place)] }]

    lazy_zones_map.merge(new_zones)
  end
end

Instance Method Details

#<=>(zone) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 234

def <=>(zone)
  result = (utc_offset <=> zone.utc_offset)
  result = (name <=> zone.name) if result == 0
  result
end

#=~(re) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 242

def =~(re)
  re === name || re === MAPPING[name]
end

#at(secs) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 267

def at(secs)
  Time.at(secs).utc.in_time_zone(self)
end

#formatted_offset(colon = true, alternate_utc_string = nil) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 228

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) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 256

def local(*args)
  time = Time.utc(*args)
  ActiveSupport::TimeWithZone.new(nil, self, time)
end

#local_to_utc(time, dst = true) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 326

def local_to_utc(time, dst=true)
  tzinfo.local_to_utc(time, dst)
end

#now ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 308

def now
  time_now.utc.in_time_zone(self)
end

#parse(str, now = now) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 282

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, 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) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 338

def period_for_local(time, dst=true)
  tzinfo.period_for_local(time, dst)
end

#period_for_utc(time) ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 332

def period_for_utc(time)
  tzinfo.period_for_utc(time)
end

#to_s ⇒ Object

Returns a textual representation of this time zone.



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 247

def to_s
  "(GMT#{formatted_offset}) #{name}"
end

#today ⇒ Object

Return the current date in this time zone.



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 313

def today
  tzinfo.now.to_date
end

#utc_offset ⇒ Object

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



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 217

def utc_offset
  if @utc_offset
    @utc_offset
  else
    @current_period ||= tzinfo.try(:current_period)
    @current_period.try(:utc_offset)
  end
end

#utc_to_local(time) ⇒ Object

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 Time#in_time_zone() instead.



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# File 'activesupport/lib/active_support/values/time_zone.rb', line 320

def utc_to_local(time)
  tzinfo.utc_to_local(time)
end