Class: TimeZone

Inherits:
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 142 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 Initializer, you can access this TimeZone object via Time.zone:

# environment.rb:
Rails::Initializer.run do |config|
  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",
  "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/Argentina/Buenos_Aires",
  "Buenos Aires"                 => "America/Argentina/Buenos_Aires",
  "Georgetown"                   => "America/Argentina/San_Juan",
  "Greenland"                    => "America/Godthab",
  "Mid-Atlantic"                 => "Atlantic/South_Georgia",
  "Azores"                       => "Atlantic/Azores",
  "Cape Verde Is."               => "Atlantic/Cape_Verde",
  "Dublin"                       => "Europe/Dublin",
  "Edinburgh"                    => "Europe/Dublin",
  "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",
  "Kyev"                         => "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/Katmandu",
  "Astana"                       => "Asia/Dhaka",
  "Dhaka"                        => "Asia/Dhaka",
  "Sri Jayawardenepura"          => "Asia/Dhaka",
  "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",
  "Ulaan Bataar"                 => "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."                  => "Asia/Magadan",
  "New Caledonia"                => "Pacific/Noumea",
  "Fiji"                         => "Pacific/Fiji",
  "Kamchatka"                    => "Asia/Kamchatka",
  "Marshall Is."                 => "Pacific/Majuro",
  "Auckland"                     => "Pacific/Auckland",
  "Wellington"                   => "Pacific/Auckland",
  "Nuku'alofa"                   => "Pacific/Tongatapu"
}.each { |name, zone| name.freeze; zone.freeze }
ZONES = 
[]
ZONES_MAP = 
{}
US_ZONES = 
ZONES.find_all { |z| z.name =~ /US|Arizona|Indiana|Hawaii|Alaska/ }

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, utc_offset, 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 'lib/active_support/values/time_zone.rb', line 179

def initialize(name, utc_offset, tzinfo = nil)
  @name = name
  @utc_offset = utc_offset
  @tzinfo = tzinfo
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/active_support/values/time_zone.rb', line 173

def name
  @name
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 'lib/active_support/values/time_zone.rb', line 376

def [](arg)
  case arg
    when String
      ZONES_MAP[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 ⇒ 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 'lib/active_support/values/time_zone.rb', line 367

def all
  ZONES
end

.create ⇒ Object 



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

alias_method :create, :new

.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 'lib/active_support/values/time_zone.rb', line 360

def new(name)
  self[name]
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 'lib/active_support/values/time_zone.rb', line 390

def us_zones
  US_ZONES
end

Instance Method Details

#<=>(zone) ⇒ Object

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



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# File 'lib/active_support/values/time_zone.rb', line 197

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

#at(secs) ⇒ Object

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

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 'lib/active_support/values/time_zone.rb', line 222

def at(secs)
  utc = Time.at(secs).utc rescue DateTime.civil(1970).since(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 'lib/active_support/values/time_zone.rb', line 191

def formatted_offset(colon=true, alternate_utc_string = nil)
  utc_offset == 0 && alternate_utc_string || utc_offset.to_utc_offset_s(colon)
end

#local(*args) ⇒ Object

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

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 'lib/active_support/values/time_zone.rb', line 212

def local(*args)
  time = Time.utc_time(*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 'lib/active_support/values/time_zone.rb', line 268

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. Example:

Time.zone = 'Hawaii'  # => "Hawaii"
Time.zone.now         # => Wed, 23 Jan 2008 20:24:27 HST -10:00



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# File 'lib/active_support/values/time_zone.rb', line 252

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. Example:

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 'lib/active_support/values/time_zone.rb', line 236

def parse(str, now=now)
  date_parts = Date._parse(str)
  return if date_parts.blank?
  time = Time.parse(str, now) rescue DateTime.parse(str)
  if date_parts[:offset].nil?
    ActiveSupport::TimeWithZone.new(nil, self, time)
  else
    time.in_time_zone(self)
  end
end

#period_for_local(time, dst = true) ⇒ Object

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



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# File 'lib/active_support/values/time_zone.rb', line 278

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 'lib/active_support/values/time_zone.rb', line 273

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 'lib/active_support/values/time_zone.rb', line 204

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

#today ⇒ Object

Return the current date in this time zone.



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# File 'lib/active_support/values/time_zone.rb', line 257

def today
  tzinfo.now.to_date
end

#tzinfo ⇒ Object

TODO: Preload instead of lazy load for thread safety



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# File 'lib/active_support/values/time_zone.rb', line 283

def tzinfo
  @tzinfo ||= TZInfo::Timezone.get(MAPPING[name])
end

#utc_offset ⇒ Object 



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# File 'lib/active_support/values/time_zone.rb', line 185

def utc_offset
  @utc_offset ||= tzinfo.current_period.utc_offset
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 'lib/active_support/values/time_zone.rb', line 263

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