class ActiveSupport::TimeZone

Parent:: Object
Included modules:

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.)

Constants

MAPPING: Keys are Rails TimeZone names, values are TZInfo identifiers.
UTC_OFFSET_WITHOUT_COLON
UTC_OFFSET_WITH_COLON

Attributes

name[R]

tzinfo[R]

Public Class Methods

[](arg) Show source

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.

# File activesupport/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

all() Show source

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.

# File activesupport/lib/active_support/values/time_zone.rb, line 379
def all
  @zones ||= zones_map.values.sort
end

create(name, utc_offset = nil, tzinfo = nil)

Alias for: new

find_tzinfo(name) Show source

# File activesupport/lib/active_support/values/time_zone.rb, line 362
def self.find_tzinfo(name)
  TZInfo::TimezoneProxy.new(MAPPING[name] || name)
end

new(name, utc_offset = nil, tzinfo = nil) Show source

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).

# File activesupport/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

Also aliased as: create

new(name) Show source

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.)

# File activesupport/lib/active_support/values/time_zone.rb, line 372
def new(name)
  self[name]
end

seconds_to_utc_offset(seconds, colon = true) Show source

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"

# File activesupport/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_zones() Show source

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

# File activesupport/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_map() Show source

# File activesupport/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

Public Instance Methods

<=>(zone) Show source

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

# File activesupport/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) Show source

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

# File activesupport/lib/active_support/values/time_zone.rb, line 248
def =~(re)
  re === name || re === MAPPING[name]
end

at(secs) Show source

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

# File activesupport/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) Show source

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

# File activesupport/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) Show source

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

# File activesupport/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) Show source

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

# File activesupport/lib/active_support/values/time_zone.rb, line 342
def local_to_utc(time, dst=true)
  tzinfo.local_to_utc(time, dst)
end

now() Show source

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

# File activesupport/lib/active_support/values/time_zone.rb, line 314
def now
  time_now.utc.in_time_zone(self)
end

parse(str, now=now()) Show source

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 #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

# File activesupport/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) Show source

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

# File activesupport/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) Show source

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

# File activesupport/lib/active_support/values/time_zone.rb, line 348
def period_for_utc(time)
  tzinfo.period_for_utc(time)
end

to_s() Show source

Returns a textual representation of this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 253
def to_s
  "(GMT#{formatted_offset}) #{name}"
end

today() Show source

Return the current date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 319
def today
  tzinfo.now.to_date
end

tomorrow() Show source

Returns the next date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 324
def tomorrow
  today + 1
end

utc_offset() Show source

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

# File activesupport/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) Show source

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 DateAndTime::Zones#in_time_zone instead.

# File activesupport/lib/active_support/values/time_zone.rb, line 336
def utc_to_local(time)
  tzinfo.utc_to_local(time)
end

yesterday() Show source

Returns the previous date in this time zone.

# File activesupport/lib/active_support/values/time_zone.rb, line 329
def yesterday
  today - 1
end