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 ENV['TZ'] zone
class TimeWithZone
include Comparable
attr_reader :time_zone
def initialize(utc_time, time_zone = nil, local_time = nil)
@utc = utc_time
@time = local_time
@time_zone = time_zone
end
# Returns a Time instance that represents the time in time_zone
def time
@time ||= utc? ? @utc : time_zone.utc_to_local(@utc)
end
# Returns a Time instance that represents the time in UTC
def utc
@utc ||= utc? ? @time : time_zone.local_to_utc(@time)
end
alias_method :comparable_time, :utc
# Returns the underlying TZInfo::TimezonePeriod for the local time
def period
@period ||= get_period_for_local
end
# Returns the simultaneous time in the specified zone
def in_time_zone(new_zone)
utc.in_time_zone(new_zone)
end
# Returns the simultaneous time in Time.zone
def in_current_time_zone
utc.in_current_time_zone
end
# Changes the time zone without converting the time
def change_time_zone(new_zone)
time.change_time_zone(new_zone)
end
# Changes the time zone to Time.zone without converting the time
def change_time_zone_to_current
time.change_time_zone_to_current
end
# Returns a Time.local() instance of the simultaneous time in your system's ENV['TZ'] zone
def localtime
utc.dup.localtime # use #dup because Time#localtime is destructive
end
def dst?
utc? ? false : period.dst?
end
# The TimeZone class has no zone for UTC, so this class uses the absence of a time zone to indicate UTC
def utc?
!time_zone
end
def utc_offset
utc? ? 0 : period.utc_total_offset
end
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
utc? ? 'UTC' : period.abbreviation.to_s
end
def inspect
"#{time.strftime('%a, %d %b %Y %H:%M:%S')} #{zone} #{formatted_offset}"
end
def xmlschema
"#{time.strftime("%Y-%m-%dT%H:%M:%S")}#{formatted_offset(true, 'Z')}"
end
def to_json(options = nil)
%("#{time.strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)}")
end
# :db format outputs time in UTC; all others output time in local. Uses TimeWithZone's strftime, so %Z and %z 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 %Z and %z 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
# A TimeProxy acts like a Time, so just return self
def to_time
self
end
# so that self acts_like?(:time)
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?
# Neuter freeze because freezing can cause problems with lazy loading of attributes
def freeze
self
end
# Ensure proxy class responds to all methods that underlying time instance responds to
def respond_to?(sym)
super || time.respond_to?(sym)
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 = result.change_time_zone(time_zone) if result.acts_like?(:time)
result
end
private
def get_period_for_local
t = time
begin
time_zone.period_for_local(t, true)
rescue ::TZInfo::PeriodNotFound # failover logic from TzTime
t -= 1.hour
retry
end
end
end
end
