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 
# File activesupport/lib/active_support/values/time_zone.rb, line 239
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

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.

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

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.

create(name)
Alias for: new
find_tzinfo(name) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 207
def find_tzinfo(name)
  TZInfo::TimezoneProxy.new(MAPPING[name] || name)
end
new(name, utc_offset = nil, tzinfo = nil) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 270
def initialize(name, utc_offset = nil, tzinfo = nil)
  @name = name
  @utc_offset = utc_offset
  @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
end

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).

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

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.)

Also aliased as: create
seconds_to_utc_offset(seconds, colon = true) Show source 
# 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

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"
us_zones() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 257
def us_zones
  @us_zones ||= all.find_all { |z| z.name =~ /US|Arizona|Indiana|Hawaii|Alaska/ }
end

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

Public Instance Methods

<=>(zone) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 297
def <=>(zone)
  return unless zone.respond_to? :utc_offset
  result = (utc_offset <=> zone.utc_offset)
  result = (name <=> zone.name) if result == 0
  result
end

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

=~(re) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 306
def =~(re)
  re === name || re === MAPPING[name]
end

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

at(secs) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 331
def at(secs)
  Time.at(secs).utc.in_time_zone(self)
end

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
formatted_offset(colon=true, alternate_utc_string = nil) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 291
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

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

local(*args) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 320
def local(*args)
  time = Time.utc(*args)
  ActiveSupport::TimeWithZone.new(nil, self, time)
end

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
local_to_utc(time, dst=true) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 405
def local_to_utc(time, dst=true)
  tzinfo.local_to_utc(time, dst)
end

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

now() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 377
def now
  time_now.utc.in_time_zone(self)
end

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
parse(str, now=now()) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 351
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, parts[:year] || parts[:mon] ? 1 : 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

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

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
period_for_local(time, dst=true) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 417
def period_for_local(time, dst=true)
  tzinfo.period_for_local(time, dst)
end

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

period_for_utc(time) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 411
def period_for_utc(time)
  tzinfo.period_for_utc(time)
end

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

to_s() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 311
def to_s
  "(GMT#{formatted_offset}) #{name}"
end

Returns a textual representation of this time zone.

today() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 382
def today
  tzinfo.now.to_date
end

Return the current date in this time zone.

tomorrow() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 387
def tomorrow
  today + 1
end

Returns the next date in this time zone.

utc_offset() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 281
def utc_offset
  if @utc_offset
    @utc_offset
  else
    tzinfo.current_period.utc_offset if tzinfo && tzinfo.current_period
  end
end

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

utc_to_local(time) Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 399
def utc_to_local(time)
  tzinfo.utc_to_local(time)
end

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.

yesterday() Show source 
# File activesupport/lib/active_support/values/time_zone.rb, line 392
def yesterday
  today - 1
end

Returns the previous date in this time zone.

© 2004–2018 David Heinemeier Hansson
Licensed under the MIT License.