1  module ActiveSupport #:nodoc:
   2    module CoreExtensions #:nodoc:
   3      module Time #:nodoc:
   4        module Zones
   5          def self.included(base) #:nodoc:
   6            base.extend(ClassMethods) if base == ::Time # i.e., don't include class methods in DateTime
   7          end
   8          
   9          module ClassMethods
  10            attr_accessor :zone_default
  11            
  12            # Returns the TimeZone for the current request, if this has been set (via Time.zone=). 
  13            # If <tt>Time.zone</tt> has not been set for the current request, returns the TimeZone specified in <tt>config.time_zone</tt>.
  14            def zone
  15              Thread.current[:time_zone] || zone_default
  16            end
  17 
  18            # Sets <tt>Time.zone</tt> to a TimeZone object for the current request/thread. 
  19            #
  20            # This method accepts any of the following:
  21            #
  22            # * A Rails TimeZone object.
  23            # * An identifier for a Rails TimeZone object (e.g., "Eastern Time (US & Canada)", <tt>-5.hours</tt>).
  24            # * A TZInfo::Timezone object.
  25            # * An identifier for a TZInfo::Timezone object (e.g., "America/New_York").
  26            #
  27            # Here's an example of how you might set <tt>Time.zone</tt> on a per request basis -- <tt>current_user.time_zone</tt>
  28            # just needs to return a string identifying the user's preferred TimeZone:
  29            #
  30            #   class ApplicationController < ActionController::Base
  31            #     before_filter :set_time_zone
  32            #
  33            #     def set_time_zone
  34            #       Time.zone = current_user.time_zone
  35            #     end
  36            #   end
  37            def zone=(time_zone)
  38              Thread.current[:time_zone] = get_zone(time_zone)
  39            end
  40            
  41            # Allows override of <tt>Time.zone</tt> locally inside supplied block; resets <tt>Time.zone</tt> to existing value when done.
  42            def use_zone(time_zone)
  43              old_zone, ::Time.zone = ::Time.zone, get_zone(time_zone)
  44              yield
  45            ensure
  46              ::Time.zone = old_zone
  47            end
  48            
  49            # Returns <tt>Time.zone.now</tt> when <tt>config.time_zone</tt> is set, otherwise just returns <tt>Time.now</tt>.
  50            def current
  51              ::Time.zone_default ? ::Time.zone.now : ::Time.now
  52            end
  53            
  54            private
  55              def get_zone(time_zone)
  56                return time_zone if time_zone.nil? || time_zone.is_a?(TimeZone)
  57                # lookup timezone based on identifier (unless we've been passed a TZInfo::Timezone)
  58                unless time_zone.respond_to?(:period_for_local)
  59                  time_zone = TimeZone[time_zone] || TZInfo::Timezone.get(time_zone) rescue nil
  60                end
  61                # Return if a TimeZone instance, or wrap in a TimeZone instance if a TZInfo::Timezone
  62                if time_zone
  63                  time_zone.is_a?(TimeZone) ? time_zone : TimeZone.create(time_zone.name, nil, time_zone)
  64                end
  65              end
  66          end
  67          
  68          # Returns the simultaneous time in <tt>Time.zone</tt>.
  69          #
  70          #   Time.zone = 'Hawaii'         # => 'Hawaii'
  71          #   Time.utc(2000).in_time_zone  # => Fri, 31 Dec 1999 14:00:00 HST -10:00
  72          #
  73          # This method is similar to Time#localtime, except that it uses <tt>Time.zone</tt> as the local zone
  74          # instead of the operating system's time zone.
  75          #
  76          # You can also pass in a TimeZone instance or string that identifies a TimeZone as an argument, 
  77          # and the conversion will be based on that zone instead of <tt>Time.zone</tt>.
  78          #
  79          #   Time.utc(2000).in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
  80          def in_time_zone(zone = ::Time.zone)
  81            ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.__send__(:get_zone, zone))
  82          end
  83        end
  84      end
  85    end
  86  en