class ActiveSupport::TimeZone - activesupport-4.2.4 Documentation

# class ActiveSupport::TimeZone

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) click to toggle 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 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

all() click to toggle 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 lib/active_support/values/time_zone.rb, line 223
    def all
      @zones ||= zones_map.values.sort
    end

create(name)
Alias for: new
find_tzinfo(name) click to toggle source

    # File lib/active_support/values/time_zone.rb, line 207
    def find_tzinfo(name)
      TZInfo::TimezoneProxy.new(MAPPING[name] || name)
    end

new(name) click to toggle 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 lib/active_support/values/time_zone.rb, line 216
    def new(name)
      self[name]
    end

Also aliased as: create
new(name, utc_offset = nil, tzinfo = nil) click to toggle 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 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)
      @current_period = nil
    end

seconds_to_utc_offset(seconds, colon = true) click to toggle 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 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

us_zones() click to toggle source

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

    # File 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

### Public Instance Methods

<=>(zone) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 295
    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) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 304
    def =~(re)
      re === name || re === MAPPING[name]
    end

at(secs) click to toggle 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 lib/active_support/values/time_zone.rb, line 329
    def at(secs)
      Time.at(secs).utc.in_time_zone(self)
    end

formatted_offset(colon=true, alternate_utc_string = nil) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 289
    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) click to toggle 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 lib/active_support/values/time_zone.rb, line 318
    def local(*args)
      time = Time.utc(*args)
      ActiveSupport::TimeWithZone.new(nil, self, time)
    end

local_to_utc(time, dst=true) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 403
    def local_to_utc(time, dst=true)
      tzinfo.local_to_utc(time, dst)
    end

now() click to toggle 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 lib/active_support/values/time_zone.rb, line 375
    def now
      time_now.utc.in_time_zone(self)
    end

parse(str, now=now()) click to toggle 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

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

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

period_for_local(time, dst=true) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 415
    def period_for_local(time, dst=true)
      tzinfo.period_for_local(time, dst)
    end

period_for_utc(time) click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 409
    def period_for_utc(time)
      tzinfo.period_for_utc(time)
    end

to_s() click to toggle source

Returns a textual representation of this time zone.

    # File lib/active_support/values/time_zone.rb, line 309
    def to_s
      "(GMT#{formatted_offset}) #{name}"
    end

today() click to toggle source

Return the current date in this time zone.

    # File lib/active_support/values/time_zone.rb, line 380
    def today
      tzinfo.now.to_date
    end

tomorrow() click to toggle source

Returns the next date in this time zone.

    # File lib/active_support/values/time_zone.rb, line 385
    def tomorrow
      today + 1
    end

utc_offset() click to toggle source

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

    # File lib/active_support/values/time_zone.rb, line 278
    def utc_offset
      if @utc_offset
        @utc_offset
      else
        @current_period ||= tzinfo.current_period if tzinfo
        @current_period.utc_offset if @current_period
      end
    end

utc_to_local(time) click to toggle 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 lib/active_support/values/time_zone.rb, line 397
    def utc_to_local(time)
      tzinfo.utc_to_local(time)
    end

yesterday() click to toggle source

Returns the previous date in this time zone.

    # File lib/active_support/values/time_zone.rb, line 390
    def yesterday
      today - 1
    end

### Private Instance Methods

time_now() click to toggle source

    # File lib/active_support/values/time_zone.rb, line 424
    def time_now
      Time.now
    end