Class: ActiveSupport::TimeZone

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
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",
  "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/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",
  "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"
}
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).


214
215
216
217
218
219
# File 'lib/active_support/values/time_zone.rb', line 214

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

Instance Attribute Details

#nameObject (readonly)

Returns the value of attribute name


207
208
209
# File 'lib/active_support/values/time_zone.rb', line 207

def name
  @name
end

#tzinfoObject (readonly)

Returns the value of attribute tzinfo


208
209
210
# File 'lib/active_support/values/time_zone.rb', line 208

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.


395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
# File 'lib/active_support/values/time_zone.rb', line 395

def [](arg)
  case arg
    when String
    begin
      @lazy_zones_map[arg] ||= create(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

.allObject

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.


379
380
381
# File 'lib/active_support/values/time_zone.rb', line 379

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

.createObject


367
# File 'lib/active_support/values/time_zone.rb', line 367

alias_method :create, :new

.find_tzinfo(name) ⇒ Object


362
363
364
# File 'lib/active_support/values/time_zone.rb', line 362

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

.new(name) ⇒ Object

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.)


372
373
374
# File 'lib/active_support/values/time_zone.rb', line 372

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"

198
199
200
201
202
203
204
# File 'lib/active_support/values/time_zone.rb', line 198

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_zonesObject

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


413
414
415
# File 'lib/active_support/values/time_zone.rb', line 413

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

.zones_mapObject


383
384
385
386
387
388
# File 'lib/active_support/values/time_zone.rb', line 383

def zones_map
  @zones_map ||= begin
    MAPPING.each_key {|place| self[place]} # load all the zones
    @lazy_zones_map
  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.


239
240
241
242
243
244
# File 'lib/active_support/values/time_zone.rb', line 239

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) ⇒ Object

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


248
249
250
# File 'lib/active_support/values/time_zone.rb', line 248

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

273
274
275
# File 'lib/active_support/values/time_zone.rb', line 273

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”.


233
234
235
# File 'lib/active_support/values/time_zone.rb', line 233

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

262
263
264
265
# File 'lib/active_support/values/time_zone.rb', line 262

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.


342
343
344
# File 'lib/active_support/values/time_zone.rb', line 342

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

#nowObject

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

314
315
316
# File 'lib/active_support/values/time_zone.rb', line 314

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

288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
# File 'lib/active_support/values/time_zone.rb', line 288

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.


354
355
356
# File 'lib/active_support/values/time_zone.rb', line 354

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.


348
349
350
# File 'lib/active_support/values/time_zone.rb', line 348

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

#periods_for_local(time) ⇒ Object

:nodoc:


358
359
360
# File 'lib/active_support/values/time_zone.rb', line 358

def periods_for_local(time) #:nodoc:
  tzinfo.periods_for_local(time)
end

#to_sObject

Returns a textual representation of this time zone.


253
254
255
# File 'lib/active_support/values/time_zone.rb', line 253

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

#todayObject

Return the current date in this time zone.


319
320
321
# File 'lib/active_support/values/time_zone.rb', line 319

def today
  tzinfo.now.to_date
end

#tomorrowObject

Returns the next date in this time zone.


324
325
326
# File 'lib/active_support/values/time_zone.rb', line 324

def tomorrow
  today + 1
end

#utc_offsetObject

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


222
223
224
225
226
227
228
229
# File 'lib/active_support/values/time_zone.rb', line 222

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.


336
337
338
# File 'lib/active_support/values/time_zone.rb', line 336

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

#yesterdayObject

Returns the previous date in this time zone.


329
330
331
# File 'lib/active_support/values/time_zone.rb', line 329

def yesterday
  today - 1
end