Module: Lazier::TimeZone

Extended by:
ActiveSupport::Concern
Defined in:
lib/lazier/datetime.rb

Overview

Extensions for timezone objects.

Defined Under Namespace

Modules: ClassMethods

Instance Method Summary collapse

Instance Method Details

#aliases(dst_label = nil) ⇒ Array

Returns a list of valid aliases (city names) for this timezone (basing on offset).

Parameters:

  • dst_label (String) (defaults to: nil) —

    Label for the DST indication. Defaults to (DST).

Returns:

  • (Array) —

    A list of aliases for this timezone



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# File 'lib/lazier/datetime.rb', line 388

def aliases(dst_label = nil)
  reference = self.name
  reference = self.class::MAPPING[self.name] if self.class::MAPPING.has_key?(self.name) # We are an alias
  reference = reference.gsub("_", " ")

  if @aliases.blank? then
    # First we search for aliases by name
    @aliases = [reference]

    self.class::MAPPING.each do |name, zone|
      if zone.gsub("_", " ") == reference then
        if name == "International Date Line West" || name == "UTC" || name.include?("(US & Canada)")
          @aliases << name
        else
          @aliases << reference.gsub(/\/.*/, "/" + name)
        end
      end
    end

    @aliases = @aliases.uniq.compact.sort
  end

  @aliases
end

#current_offset(rational = false, date = nil) ⇒ Fixnum|Rational

Returns the current offset for this timezone, taking care of Daylight Saving Time (DST).

Parameters:

  • rational (Boolean) (defaults to: false) —

    If to return the offset as a Rational.

  • date (DateTime) (defaults to: nil) —

    The date to consider. Defaults to now.

Returns:

  • (Fixnum|Rational) —

    The offset of this timezone.



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# File 'lib/lazier/datetime.rb', line 418

def current_offset(rational = false, date = nil)
  date ||= ::DateTime.now

  dst_period = self.dst_period

  rv = (self.period_for_utc(date.utc).dst? ? self.dst_offset : self.offset)
  rational ? self.class.rationalize_offset(rv) : rv
end

#dst_correction(rational = false, year = nil) ⇒ Fixnum|Rational

Return the correction applied to the standard offset the timezone when the Daylight Saving Time (DST) is active.

Parameters:

  • rational (Boolean) (defaults to: false) —

    If to return the offset as a Rational.

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

Returns:

  • (Fixnum|Rational) —

    The correction for dst.



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# File 'lib/lazier/datetime.rb', line 468

def dst_correction(rational = false, year = nil)
  period = self.dst_period(year)
  rv = period ? period.std_offset : 0
  rational ? self.class.rationalize_offset(rv) : rv
end

#dst_name(dst_label = nil, year = nil, name = nil) ⇒ String

Returns the name for this zone with Daylight Saving Time (DST) active.

Parameters:

  • dst_label (String) (defaults to: nil) —

    Label for the DST indication. Defaults to (DST).

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

  • name (String) (defaults to: nil) —

    The name to use for this zone. Defaults to the zone name.

Returns:

  • (String) —

    The name for the zone with DST or nil, if the timezone doesn't use DST for that year.



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# File 'lib/lazier/datetime.rb', line 491

def dst_name(dst_label = nil, year = nil, name = nil)
  dst_label ||= "(DST)"
  name ||= self.name

  self.uses_dst?(year) ? "#{name} #{dst_label}" : nil
end

#dst_offset(rational = false, year = nil) ⇒ Fixnum|Rational

Returns the standard offset for this timezone timezone when the Daylight Saving Time (DST) is active.

Parameters:

  • rational (Boolean) (defaults to: false) —

    If to return the offset as a Rational.

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

Returns:

  • (Fixnum|Rational) —

    The DST offset for this timezone or 0, if the timezone doesn't use DST for that year.



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# File 'lib/lazier/datetime.rb', line 479

def dst_offset(rational = false, year = nil)
  period = self.dst_period(year)
  rv = period ? period.utc_total_offset : 0
  rational ? self.class.rationalize_offset(rv) : rv
end

#dst_period(year = nil) ⇒ TimezonePeriod

Gets a period for this timezone when the Daylight Saving Time (DST) is active (it takes care of different hemispheres).

Parameters:

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

Returns:

  • (TimezonePeriod) —

    A period when the Daylight Saving Time (DST) is active or nil if the timezone doesn't use DST for that year.



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# File 'lib/lazier/datetime.rb', line 440

def dst_period(year = nil)
  year ||= ::Date.today.year

  nothern_summer = ::DateTime.civil(year, 7, 15).utc # This is a representation of a summer period in the Northern Hemisphere.
  southern_summer = ::DateTime.civil(year, 1, 15).utc # This is a representation of a summer period in the Northern Hemisphere.

  period = self.period_for_utc(nothern_summer)
  period = self.period_for_utc(southern_summer) if !period.dst?
  period.dst? ? period : nil
end

#offset(rational = false) ⇒ Fixnum|Rational

Returns the standard offset for this timezone.

Parameters:

  • rational (Boolean) (defaults to: false) —

    If to return the offset as a Rational.

Returns:

  • (Fixnum|Rational) —

    The offset of this timezone.



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# File 'lib/lazier/datetime.rb', line 431

def offset(rational = false)
  rv = self.utc_offset
  rational ? self.class.rationalize_offset(rv) : rv
end

#to_str(name = nil, colon = true) ⇒ String

Returns the name for this zone with Daylight Saving Time (DST) active.

Parameters:

  • name (String) (defaults to: nil) —

    The name to use for this zone. Defaults to the zone name.

  • colon (Boolean) (defaults to: true) —

    If to put the colon in the output string.

Returns:

  • (String) —

    The name for this zone.



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# File 'lib/lazier/datetime.rb', line 503

def to_str(name = nil, colon = true)
  name ||= self.aliases.first
  "(GMT#{self.formatted_offset(colon)}) #{name}"
end

#to_str_parameterized(with_offset = true, name = nil) ⇒ String

Returns a parametized string representation for this zone.

Parameters:

  • with_offset (Boolean) (defaults to: true) —

    If to include offset into the representation.

  • name (String) (defaults to: nil) —

    The name to use for this zone. Defaults to the zone name.

Returns:

  • (String) —

    The parametized string representation for this zone.



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# File 'lib/lazier/datetime.rb', line 532

def to_str_parameterized(with_offset = true, name = nil)
  ::ActiveSupport::TimeZone.parameterize_zone(name || self.to_str, with_offset)
end

#to_str_with_dst(dst_label = nil, year = nil, name = nil) ⇒ String

Returns a string representation for this zone with Daylight Saving Time (DST) active.

Parameters:

  • dst_label (String) (defaults to: nil) —

    Label for the DST indication. Defaults to (DST).

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

  • name (String) (defaults to: nil) —

    The name to use for this zone. Defaults to the zone name.

Returns:

  • (String) —

    The string representation for the zone with DST or nil, if the timezone doesn't use DST for that year.



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# File 'lib/lazier/datetime.rb', line 514

def to_str_with_dst(dst_label = nil, year = nil, name = nil)
  dst_label ||= "(DST)"
  name ||= self.aliases.first

  if self.uses_dst?(year) then
    period = self.dst_period(year)
    offset = self.class.seconds_to_utc_offset(period.utc_total_offset)
    "(GMT#{offset}) #{name} #{dst_label}"
  else
    nil
  end
end

#to_str_with_dst_parameterized(dst_label = nil, with_offset = true, year = nil, name = nil) ⇒ String

Returns a parametized string representation for this zone with Daylight Saving Time (DST) active.

Parameters:

  • dst_label (String) (defaults to: nil) —

    Label for the DST indication. Defaults to (DST).

  • with_offset (Boolean) (defaults to: true) —

    If to include offset into the representation.

  • year (Fixnum) (defaults to: nil) —

    The year to which refer to. Defaults to the current year.

  • name (String) (defaults to: nil) —

    The name to use for this zone. Defaults to the zone name.

Returns:

  • (String) —

    The parametized string representation for this zone with DST or nil, if the timezone doesn't use DST for that year.



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# File 'lib/lazier/datetime.rb', line 543

def to_str_with_dst_parameterized(dst_label = nil, with_offset = true, year = nil, name = nil)
  rv = self.to_str_with_dst(dst_label, year, name)
  rv ? ::ActiveSupport::TimeZone.parameterize_zone(rv) : nil
end

#uses_dst?(reference = nil) ⇒ Boolean

Checks if the timezone uses Daylight Saving Time (DST) for that date or year.

Parameters:

  • reference (Object) (defaults to: nil) —

    The date or year to check. Defaults to the current year.

Returns:

  • (Boolean) —

    true if the zone uses DST for that date or year, false otherwise.



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# File 'lib/lazier/datetime.rb', line 455

def uses_dst?(reference = nil)
  if reference.respond_to?(:year) && reference.respond_to?(:utc) then # This is a date like object
    self.dst_period(reference.year).present? && self.period_for_utc(reference.utc).dst?
  else
    self.dst_period(reference).present?
  end
end