class TZInfo::Timezone - tzinfo-0.3.42 Documentation

# class TZInfo::Timezone

Timezone is the base class of all timezones. It provides a factory method get to access timezones by identifier. Once a specific Timezone has been retrieved, DateTimes, Times and timestamps can be converted between the UTC and the local time for the zone. For example:

    tz = TZInfo::Timezone.get('America/New_York')
    puts tz.utc_to_local(DateTime.new(2005,8,29,15,35,0)).to_s
    puts tz.local_to_utc(Time.utc(2005,8,29,11,35,0)).to_s
    puts tz.utc_to_local(1125315300).to_s

Each time conversion method returns an object of the same type it was passed.

The timezone information all comes from the tz database (see www.twinsun.com/tz/tz-link.htm)

### Public Class Methods

_load(data) click to toggle source

Loads a marshalled Timezone.

    # File lib/tzinfo/timezone.rb, line 522
    def self._load(data)
      Timezone.get(data)
    end

all() click to toggle source

Returns an array containing all the available Timezones.

Returns TimezoneProxy objects to avoid the overhead of loading Timezone definitions until a conversion is actually required.

    # File lib/tzinfo/timezone.rb, line 161
    def self.all
      get_proxies(all_identifiers)
    end

all_country_zone_identifiers() click to toggle source

Returns all the zone identifiers defined for all Countries. This is not the complete set of zone identifiers as some are not country specific (e.g. 'Etc/GMT'). You can obtain a Timezone instance for a given identifier with the get method.

    # File lib/tzinfo/timezone.rb, line 220
    def self.all_country_zone_identifiers
      Country.all_codes.inject([]) {|zones,country|
        zones += Country.get(country).zone_identifiers
      }
    end

all_country_zones() click to toggle source

Returns all the Timezones defined for all Countries. This is not the complete set of Timezones as some are not country specific (e.g. 'Etc/GMT').

Returns TimezoneProxy objects to avoid the overhead of loading Timezone definitions until a conversion is actually required.

    # File lib/tzinfo/timezone.rb, line 210
    def self.all_country_zones
      Country.all_codes.inject([]) {|zones,country|
        zones += Country.get(country).zones
      }
    end

all_data_zone_identifiers() click to toggle source

Returns an array containing the identifiers of all the available Timezones that are based on data (are not links to other Timezones)..

    # File lib/tzinfo/timezone.rb, line 183
    def self.all_data_zone_identifiers
      load_index
      Indexes::Timezones.data_timezones
    end

all_data_zones() click to toggle source

Returns an array containing all the available Timezones that are based on data (are not links to other Timezones).

Returns TimezoneProxy objects to avoid the overhead of loading Timezone definitions until a conversion is actually required.

    # File lib/tzinfo/timezone.rb, line 177
    def self.all_data_zones
      get_proxies(all_data_zone_identifiers)
    end

all_identifiers() click to toggle source

Returns an array containing the identifiers of all the available Timezones.

    # File lib/tzinfo/timezone.rb, line 167
    def self.all_identifiers
      load_index
      Indexes::Timezones.timezones
    end

all_linked_zone_identifiers() click to toggle source

Returns an array containing the identifiers of all the available Timezones that are links to other Timezones.

    # File lib/tzinfo/timezone.rb, line 199
    def self.all_linked_zone_identifiers
      load_index
      Indexes::Timezones.linked_timezones
    end

all_linked_zones() click to toggle source

Returns an array containing all the available Timezones that are links to other Timezones.

Returns TimezoneProxy objects to avoid the overhead of loading Timezone definitions until a conversion is actually required.

    # File lib/tzinfo/timezone.rb, line 193
    def self.all_linked_zones
      get_proxies(all_linked_zone_identifiers)
    end

default_dst() click to toggle source

Gets the default value of the optional dst parameter of the #local_to_utc and #period_for_local methods. Can be set to nil, true or false.

    # File lib/tzinfo/timezone.rb, line 93
    def self.default_dst
      @@default_dst
    end

default_dst=(value) click to toggle source

Sets the default value of the optional dst parameter of the #local_to_utc and #period_for_local methods. Can be set to nil, true or false.

The value of ::default_dst defaults to nil if unset.

    # File lib/tzinfo/timezone.rb, line 86
    def self.default_dst=(value)
      @@default_dst = value.nil? ? nil : !!value
    end

get(identifier) click to toggle source

Returns a timezone by its identifier (e.g. “Europe/London”, “America/Chicago” or “UTC”).

Raises InvalidTimezoneIdentifier if the timezone couldn't be found.

    # File lib/tzinfo/timezone.rb, line 101
    def self.get(identifier)
      instance = @@loaded_zones[identifier]
      unless instance
        raise InvalidTimezoneIdentifier, 'Invalid identifier' if identifier !~ /^[A-Za-z0-9\+\-_]+(\/[A-Za-z0-9\+\-_]+)*$/
        identifier = identifier.gsub(/-/, '__m__').gsub(/\+/, '__p__')
        begin
          # Use a temporary variable to avoid an rdoc warning
          file = "tzinfo/definitions/#{identifier}".untaint
          require file

          m = Definitions
          identifier.split(/\//).each {|part|
            m = m.const_get(part)
          }

          info = m.get

          # Could make Timezone subclasses register an interest in an info
          # type. Since there are currently only two however, there isn't
          # much point.
          if info.kind_of?(DataTimezoneInfo)
            instance = DataTimezone.new(info)
          elsif info.kind_of?(LinkedTimezoneInfo)
            instance = LinkedTimezone.new(info)
          else
            raise InvalidTimezoneIdentifier, "No handler for info type #{info.class}"
          end

          @@loaded_zones[instance.identifier] = instance
        rescue LoadError, NameError => e
          raise InvalidTimezoneIdentifier, e.message
        end
      end

      instance
    end

get_proxy(identifier) click to toggle source

Returns a proxy for the Timezone with the given identifier. The proxy will cause the real timezone to be loaded when an attempt is made to find a period or convert a time. ::get_proxy will not validate the identifier. If an invalid identifier is specified, no exception will be raised until the proxy is used.

    # File lib/tzinfo/timezone.rb, line 143
    def self.get_proxy(identifier)
      TimezoneProxy.new(identifier)
    end

new(identifier = nil) click to toggle source

If identifier is nil calls super(), otherwise calls get. An identfier should always be passed in when called externally.

Calls superclass method

    # File lib/tzinfo/timezone.rb, line 149
    def self.new(identifier = nil)
      if identifier
        get(identifier)
      else
        super()
      end
    end

us_zone_identifiers() click to toggle source

Returns all US zone identifiers. A shortcut for TZInfo::Country.get('US').zone_identifiers.

    # File lib/tzinfo/timezone.rb, line 237
    def self.us_zone_identifiers
      Country.get('US').zone_identifiers
    end

us_zones() click to toggle source

Returns all US Timezone instances. A shortcut for TZInfo::Country.get('US').zones.

Returns TimezoneProxy objects to avoid the overhead of loading Timezone definitions until a conversion is actually required.

    # File lib/tzinfo/timezone.rb, line 231
    def self.us_zones
      Country.get('US').zones
    end

### Private Class Methods

get_proxies(identifiers) click to toggle source

Returns an array of proxies corresponding to the given array of identifiers.

    # File lib/tzinfo/timezone.rb, line 537
    def self.get_proxies(identifiers)
      identifiers.collect {|identifier| get_proxy(identifier)}
    end

load_index() click to toggle source

Loads in the index of timezones if it hasn't already been loaded.

    # File lib/tzinfo/timezone.rb, line 528
    def self.load_index
      unless @@index_loaded
        require 'tzinfo/indexes/timezones'
        @@index_loaded = true
      end
    end

### Public Instance Methods

<=>(tz) click to toggle source

Compares two Timezones based on their identifier. Returns -1 if tz is less than self, 0 if tz is equal to self and +1 if tz is greater than self.

    # File lib/tzinfo/timezone.rb, line 501
    def <=>(tz)
      identifier <=> tz.identifier
    end

_dump(limit) click to toggle source

Dumps this Timezone for marshalling.

    # File lib/tzinfo/timezone.rb, line 517
    def _dump(limit)
      identifier
    end

current_period() click to toggle source

Returns the TimezonePeriod for the current time.

    # File lib/tzinfo/timezone.rb, line 463
    def current_period
      period_for_utc(Time.now.utc)
    end

current_period_and_time() click to toggle source

Returns the current Time and TimezonePeriod as an array. The first element is the time, the second element is the period.

    # File lib/tzinfo/timezone.rb, line 469
    def current_period_and_time
      utc = Time.now.utc
      period = period_for_utc(utc)
      [period.to_local(utc), period]
    end

Also aliased as: current_time_and_period
current_time_and_period()
Alias for: current_period_and_time
eql?(tz) click to toggle source

Returns true if and only if the identifier of tz is equal to the identifier of this Timezone.

    # File lib/tzinfo/timezone.rb, line 507
    def eql?(tz)
      self == tz
    end

friendly_identifier(skip_first_part = false) click to toggle source

Returns a friendlier version of the identifier. Set skip_first_part to omit the first part of the identifier (typically a region name) where there is more than one part.

For example:

    Timezone.get('Europe/Paris').friendly_identifier(false)          #=> "Europe - Paris"
    Timezone.get('Europe/Paris').friendly_identifier(true)           #=> "Paris"
    Timezone.get('America/Indiana/Knox').friendly_identifier(false)  #=> "America - Knox, Indiana"
    Timezone.get('America/Indiana/Knox').friendly_identifier(true)   #=> "Knox, Indiana"

    # File lib/tzinfo/timezone.rb, line 272
    def friendly_identifier(skip_first_part = false)
      parts = identifier.split('/')
      if parts.empty?
        # shouldn't happen
        identifier
      elsif parts.length == 1
        parts[0]
      else
        if skip_first_part
          result = ''
        else
          result = parts[0] + ' - '
        end

        parts[1, parts.length - 1].reverse_each {|part|
          part.gsub!(/_/, ' ')

          if part.index(/[a-z]/)
            # Missing a space if a lower case followed by an upper case and the
            # name isn't McXxxx.
            part.gsub!(/([^M][a-z])([A-Z])/, '\1 \2')
            part.gsub!(/([M][a-bd-z])([A-Z])/, '\1 \2')

            # Missing an apostrophe if two consecutive upper case characters.
            part.gsub!(/([A-Z])([A-Z])/, '\1\\2')
          end

          result << part
          result << ', '
        }

        result.slice!(result.length - 2, 2)
        result
      end
    end

hash() click to toggle source

Returns a hash of this Timezone.

    # File lib/tzinfo/timezone.rb, line 512
    def hash
      identifier.hash
    end

identifier() click to toggle source

The identifier of the timezone, e.g. “Europe/Paris”.

    # File lib/tzinfo/timezone.rb, line 242
    def identifier
      raise UnknownTimezone, 'TZInfo::Timezone constructed directly'
    end

inspect() click to toggle source

Returns internal object state as a programmer-readable string.

    # File lib/tzinfo/timezone.rb, line 258
    def inspect
      "#<#{self.class}: #{identifier}>"
    end

local_to_utc(local, dst = Timezone.default_dst) { |periods| ... } click to toggle source

Converts a time in the local timezone to UTC. local can either be a DateTime, Time or timestamp (Time.to_i). The returned time has the same type as local. Any timezone information in local is ignored (it is treated as a local time).

Warning: There are local times that have no equivalent UTC times (e.g. in the transition from standard time to daylight savings time). There are also local times that have more than one UTC equivalent (e.g. in the transition from daylight savings time to standard time).

In the first case (no equivalent UTC time), a PeriodNotFound exception will be raised.

In the second case (more than one equivalent UTC time), an AmbiguousTime exception will be raised unless the optional dst parameter or block handles the ambiguity.

If the ambiguity is due to a transition from daylight savings time to standard time, the dst parameter can be used to select whether the daylight savings time or local time is used. For example,

    Timezone.get('America/New_York').local_to_utc(DateTime.new(2004,10,31,1,30,0))

would raise an AmbiguousTime exception.

Specifying dst=true would return 2004-10-31 5:30:00. Specifying dst=false would return 2004-10-31 6:30:00.

If the dst parameter does not resolve the ambiguity, and a block is specified, it is called. The block must take a single parameter - an array of the periods that need to be resolved. The block can return a single period to use to convert the time or return nil or an empty array to cause an AmbiguousTime exception to be raised.

The default value of the dst parameter can be specified by setting ::default_dst. If ::default_dst is not set, or is set to nil, then an AmbiguousTime exception will be raised in ambiguous situations unless a block is given to resolve the ambiguity.

    # File lib/tzinfo/timezone.rb, line 445
    def local_to_utc(local, dst = Timezone.default_dst)
      TimeOrDateTime.wrap(local) {|wrapped|
        if block_given?
          period = period_for_local(wrapped, dst) {|periods| yield periods }
        else
          period = period_for_local(wrapped, dst)
        end

        period.to_utc(wrapped)
      }
    end

name() click to toggle source

An alias for identifier.

    # File lib/tzinfo/timezone.rb, line 247
    def name
      # Don't use alias, as identifier gets overridden.
      identifier
    end

now() click to toggle source

Returns the current time in the timezone as a Time.

    # File lib/tzinfo/timezone.rb, line 458
    def now
      utc_to_local(Time.now.utc)
    end

period_for_local(local, dst = Timezone.default_dst) { |results| ... } click to toggle source

Returns the TimezonePeriod for the given local time. local can either be a DateTime, Time or integer timestamp (Time.to_i). Any timezone information in local is ignored (it is treated as a time in the current timezone).

Warning: There are local times that have no equivalent UTC times (e.g. in the transition from standard time to daylight savings time). There are also local times that have more than one UTC equivalent (e.g. in the transition from daylight savings time to standard time).

In the first case (no equivalent UTC time), a PeriodNotFound exception will be raised.

In the second case (more than one equivalent UTC time), an AmbiguousTime exception will be raised unless the optional dst parameter or block handles the ambiguity.

If the ambiguity is due to a transition from daylight savings time to standard time, the dst parameter can be used to select whether the daylight savings time or local time is used. For example,

    Timezone.get('America/New_York').period_for_local(DateTime.new(2004,10,31,1,30,0))

would raise an AmbiguousTime exception.

Specifying dst=true would the daylight savings period from April to October 2004. Specifying dst=false would return the standard period from October 2004 to April 2005.

If the dst parameter does not resolve the ambiguity, and a block is specified, it is called. The block must take a single parameter - an array of the periods that need to be resolved. The block can select and return a single period or return nil or an empty array to cause an AmbiguousTime exception to be raised.

The default value of the dst parameter can be specified by setting ::default_dst. If ::default_dst is not set, or is set to nil, then an AmbiguousTime exception will be raised in ambiguous situations unless a block is given to resolve the ambiguity.

    # File lib/tzinfo/timezone.rb, line 362
    def period_for_local(local, dst = Timezone.default_dst)
      results = periods_for_local(local)

      if results.empty?
        raise PeriodNotFound
      elsif results.size < 2
        results.first
      else
        # ambiguous result try to resolve

        if !dst.nil?
          matches = results.find_all {|period| period.dst? == dst}
          results = matches if !matches.empty?
        end

        if results.size < 2
          results.first
        else
          # still ambiguous, try the block

          if block_given?
            results = yield results
          end

          if results.is_a?(TimezonePeriod)
            results
          elsif results && results.size == 1
            results.first
          else
            raise AmbiguousTime, "#{local} is an ambiguous local time."
          end
        end
      end
    end

period_for_utc(utc) click to toggle source

Returns the TimezonePeriod for the given UTC time. utc can either be a DateTime, Time or integer timestamp (Time.to_i). Any timezone information in utc is ignored (it is treated as a UTC time).

    # File lib/tzinfo/timezone.rb, line 311
    def period_for_utc(utc)
      raise UnknownTimezone, 'TZInfo::Timezone constructed directly'
    end

periods_for_local(local) click to toggle source

Returns the set of TimezonePeriod instances that are valid for the given local time as an array. If you just want a single period, use #period_for_local instead and specify how ambiguities should be resolved. Returns an empty array if no periods are found for the given time.

    # File lib/tzinfo/timezone.rb, line 319
    def periods_for_local(local)
      raise UnknownTimezone, 'TZInfo::Timezone constructed directly'
    end

strftime(format, utc = Time.now.utc) click to toggle source

Converts a time in UTC to local time and returns it as a string according to the given format. The formatting is identical to Time.strftime and DateTime.strftime, except %Z is replaced with the timezone abbreviation for the specified time (for example, EST or EDT).

    # File lib/tzinfo/timezone.rb, line 481
    def strftime(format, utc = Time.now.utc)
      period = period_for_utc(utc)
      local = period.to_local(utc)
      local = Time.at(local).utc unless local.kind_of?(Time) || local.kind_of?(DateTime)
      abbreviation = period.abbreviation.to_s.gsub(/%/, '%%')

      format = format.gsub(/(.?)%Z/) do
        if $1 == '%'
          # return %%Z so the real strftime treats it as a literal %Z too
          '%%Z'
        else
          "#$1#{abbreviation}"
        end
      end

      local.strftime(format)
    end

to_s() click to toggle source

Returns a friendlier version of the identifier.

    # File lib/tzinfo/timezone.rb, line 253
    def to_s
      friendly_identifier
    end

utc_to_local(utc) click to toggle source

Converts a time in UTC to the local timezone. utc can either be a DateTime, Time or timestamp (Time.to_i). The returned time has the same type as utc. Any timezone information in utc is ignored (it is treated as a UTC time).

    # File lib/tzinfo/timezone.rb, line 401
    def utc_to_local(utc)
      TimeOrDateTime.wrap(utc) {|wrapped|
        period_for_utc(wrapped).to_local(wrapped)
      }
    end