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rails--rails/activesupport/lib/active_support/time_with_zone.rb
2009-01-30 10:53:19 -08:00

333 lines
11 KiB
Ruby

require 'tzinfo'
module ActiveSupport
# A Time-like class that can represent a time in any time zone. Necessary because standard Ruby Time instances are
# limited to UTC and the system's <tt>ENV['TZ']</tt> zone.
#
# You shouldn't ever need to create a TimeWithZone instance directly via <tt>new</tt> -- instead, Rails provides the methods
# +local+, +parse+, +at+ and +now+ on TimeZone instances, and +in_time_zone+ on Time and DateTime instances, for a more
# user-friendly syntax. Examples:
#
# Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
# Time.zone.local(2007, 2, 10, 15, 30, 45) # => Sat, 10 Feb 2007 15:30:45 EST -05:00
# Time.zone.parse('2007-02-01 15:30:45') # => Sat, 10 Feb 2007 15:30:45 EST -05:00
# Time.zone.at(1170361845) # => Sat, 10 Feb 2007 15:30:45 EST -05:00
# Time.zone.now # => Sun, 18 May 2008 13:07:55 EDT -04:00
# Time.utc(2007, 2, 10, 20, 30, 45).in_time_zone # => Sat, 10 Feb 2007 15:30:45 EST -05:00
#
# See TimeZone and ActiveSupport::CoreExtensions::Time::Zones for further documentation for these methods.
#
# TimeWithZone instances implement the same API as Ruby Time instances, so that Time and TimeWithZone instances are interchangable. Examples:
#
# t = Time.zone.now # => Sun, 18 May 2008 13:27:25 EDT -04:00
# t.hour # => 13
# t.dst? # => true
# t.utc_offset # => -14400
# t.zone # => "EDT"
# t.to_s(:rfc822) # => "Sun, 18 May 2008 13:27:25 -0400"
# t + 1.day # => Mon, 19 May 2008 13:27:25 EDT -04:00
# t.beginning_of_year # => Tue, 01 Jan 2008 00:00:00 EST -05:00
# t > Time.utc(1999) # => true
# t.is_a?(Time) # => true
# t.is_a?(ActiveSupport::TimeWithZone) # => true
class TimeWithZone
include Comparable
attr_reader :time_zone
def initialize(utc_time, time_zone, local_time = nil, period = nil)
@utc, @time_zone, @time = utc_time, time_zone, local_time
@period = @utc ? period : get_period_and_ensure_valid_local_time
end
# Returns a Time or DateTime instance that represents the time in +time_zone+.
def time
@time ||= period.to_local(@utc)
end
# Returns a Time or DateTime instance that represents the time in UTC.
def utc
@utc ||= period.to_utc(@time)
end
alias_method :comparable_time, :utc
alias_method :getgm, :utc
alias_method :getutc, :utc
alias_method :gmtime, :utc
# Returns the underlying TZInfo::TimezonePeriod.
def period
@period ||= time_zone.period_for_utc(@utc)
end
# Returns the simultaneous time in <tt>Time.zone</tt>, or the specified zone.
def in_time_zone(new_zone = ::Time.zone)
return self if time_zone == new_zone
utc.in_time_zone(new_zone)
end
# Returns a <tt>Time.local()</tt> instance of the simultaneous time in your system's <tt>ENV['TZ']</tt> zone
def localtime
utc.getlocal
end
alias_method :getlocal, :localtime
def dst?
period.dst?
end
alias_method :isdst, :dst?
def utc?
time_zone.name == 'UTC'
end
alias_method :gmt?, :utc?
def utc_offset
period.utc_total_offset
end
alias_method :gmt_offset, :utc_offset
alias_method :gmtoff, :utc_offset
def formatted_offset(colon = true, alternate_utc_string = nil)
utc? && alternate_utc_string || utc_offset.to_utc_offset_s(colon)
end
# Time uses +zone+ to display the time zone abbreviation, so we're duck-typing it.
def zone
period.zone_identifier.to_s
end
def inspect
"#{time.strftime('%a, %d %b %Y %H:%M:%S')} #{zone} #{formatted_offset}"
end
def xmlschema(fraction_digits = 0)
fraction = if fraction_digits > 0
".%i" % time.usec.to_s[0, fraction_digits]
end
"#{time.strftime("%Y-%m-%dT%H:%M:%S")}#{fraction}#{formatted_offset(true, 'Z')}"
end
alias_method :iso8601, :xmlschema
# Returns a JSON string representing the TimeWithZone. If ActiveSupport.use_standard_json_time_format is set to
# true, the ISO 8601 format is used.
#
# ==== Examples
#
# # With ActiveSupport.use_standard_json_time_format = true
# Time.utc(2005,2,1,15,15,10).in_time_zone.to_json
# # => "2005-02-01T15:15:10Z"
#
# # With ActiveSupport.use_standard_json_time_format = false
# Time.utc(2005,2,1,15,15,10).in_time_zone.to_json
# # => "2005/02/01 15:15:10 +0000"
def to_json(options = nil)
if ActiveSupport.use_standard_json_time_format
xmlschema.inspect
else
%("#{time.strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)}")
end
end
def to_yaml(options = {})
if options.kind_of?(YAML::Emitter)
utc.to_yaml(options)
else
time.to_yaml(options).gsub('Z', formatted_offset(true, 'Z'))
end
end
def httpdate
utc.httpdate
end
def rfc2822
to_s(:rfc822)
end
alias_method :rfc822, :rfc2822
# <tt>:db</tt> format outputs time in UTC; all others output time in local.
# Uses TimeWithZone's +strftime+, so <tt>%Z</tt> and <tt>%z</tt> work correctly.
def to_s(format = :default)
return utc.to_s(format) if format == :db
if formatter = ::Time::DATE_FORMATS[format]
formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
else
"#{time.strftime("%Y-%m-%d %H:%M:%S")} #{formatted_offset(false, 'UTC')}" # mimicking Ruby 1.9 Time#to_s format
end
end
# Replaces <tt>%Z</tt> and <tt>%z</tt> directives with +zone+ and +formatted_offset+, respectively, before passing to
# Time#strftime, so that zone information is correct
def strftime(format)
format = format.gsub('%Z', zone).gsub('%z', formatted_offset(false))
time.strftime(format)
end
# Use the time in UTC for comparisons.
def <=>(other)
utc <=> other
end
def between?(min, max)
utc.between?(min, max)
end
def past?
utc.past?
end
def today?
time.today?
end
def future?
utc.future?
end
def eql?(other)
utc == other
end
def +(other)
# If we're adding a Duration of variable length (i.e., years, months, days), move forward from #time,
# otherwise move forward from #utc, for accuracy when moving across DST boundaries
if duration_of_variable_length?(other)
method_missing(:+, other)
else
result = utc.acts_like?(:date) ? utc.since(other) : utc + other rescue utc.since(other)
result.in_time_zone(time_zone)
end
end
def -(other)
# If we're subtracting a Duration of variable length (i.e., years, months, days), move backwards from #time,
# otherwise move backwards #utc, for accuracy when moving across DST boundaries
if other.acts_like?(:time)
utc.to_f - other.to_f
elsif duration_of_variable_length?(other)
method_missing(:-, other)
else
result = utc.acts_like?(:date) ? utc.ago(other) : utc - other rescue utc.ago(other)
result.in_time_zone(time_zone)
end
end
def since(other)
# If we're adding a Duration of variable length (i.e., years, months, days), move forward from #time,
# otherwise move forward from #utc, for accuracy when moving across DST boundaries
if duration_of_variable_length?(other)
method_missing(:since, other)
else
utc.since(other).in_time_zone(time_zone)
end
end
def ago(other)
since(-other)
end
def advance(options)
# If we're advancing a value of variable length (i.e., years, weeks, months, days), advance from #time,
# otherwise advance from #utc, for accuracy when moving across DST boundaries
if options.detect {|k,v| [:years, :weeks, :months, :days].include? k}
method_missing(:advance, options)
else
utc.advance(options).in_time_zone(time_zone)
end
end
%w(year mon month day mday wday yday hour min sec to_date).each do |method_name|
class_eval <<-EOV, __FILE__, __LINE__ + 1
def #{method_name} # def month
time.#{method_name} # time.month
end # end
EOV
end
def usec
time.respond_to?(:usec) ? time.usec : 0
end
def to_a
[time.sec, time.min, time.hour, time.day, time.mon, time.year, time.wday, time.yday, dst?, zone]
end
def to_f
utc.to_f
end
def to_i
utc.to_i
end
alias_method :hash, :to_i
alias_method :tv_sec, :to_i
# A TimeWithZone acts like a Time, so just return +self+.
def to_time
self
end
def to_datetime
utc.to_datetime.new_offset(Rational(utc_offset, 86_400))
end
# So that +self+ <tt>acts_like?(:time)</tt>.
def acts_like_time?
true
end
# Say we're a Time to thwart type checking.
def is_a?(klass)
klass == ::Time || super
end
alias_method :kind_of?, :is_a?
def freeze
period; utc; time # preload instance variables before freezing
super
end
def marshal_dump
[utc, time_zone.name, time]
end
def marshal_load(variables)
initialize(variables[0].utc, ::Time.__send__(:get_zone, variables[1]), variables[2].utc)
end
# Ensure proxy class responds to all methods that underlying time instance responds to.
def respond_to?(sym, include_priv = false)
# consistently respond false to acts_like?(:date), regardless of whether #time is a Time or DateTime
return false if sym.to_s == 'acts_like_date?'
super || time.respond_to?(sym, include_priv)
end
# Send the missing method to +time+ instance, and wrap result in a new TimeWithZone with the existing +time_zone+.
def method_missing(sym, *args, &block)
result = time.__send__(sym, *args, &block)
result.acts_like?(:time) ? self.class.new(nil, time_zone, result) : result
end
private
def get_period_and_ensure_valid_local_time
# we don't want a Time.local instance enforcing its own DST rules as well,
# so transfer time values to a utc constructor if necessary
@time = transfer_time_values_to_utc_constructor(@time) unless @time.utc?
begin
@time_zone.period_for_local(@time)
rescue ::TZInfo::PeriodNotFound
# time is in the "spring forward" hour gap, so we're moving the time forward one hour and trying again
@time += 1.hour
retry
end
end
def transfer_time_values_to_utc_constructor(time)
::Time.utc_time(time.year, time.month, time.day, time.hour, time.min, time.sec, time.respond_to?(:usec) ? time.usec : 0)
end
def duration_of_variable_length?(obj)
ActiveSupport::Duration === obj && obj.parts.flatten.detect {|p| [:years, :months, :days].include? p }
end
end
end