aboutsummaryrefslogtreecommitdiffstats
path: root/activesupport/lib/active_support/time_with_zone.rb
blob: 8ddf233b3eae349523f082587ae21298785da83c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
require 'active_support/values/time_zone'
require 'active_support/core_ext/object/acts_like'

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 +new+.
  # Instead use methods +local+, +parse+, +at+ and +now+ on TimeZone instances,
  # and +in_time_zone+ on Time and DateTime instances.
  #
  #   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('2007-02-10 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 Time and TimeZone for further documentation of these methods.
  #
  # TimeWithZone instances implement the same API as Ruby Time instances, so
  # that Time and TimeWithZone instances are interchangeable.
  #
  #   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

    # Report class name as 'Time' to thwart type checking.
    def self.name
      'Time'
    end

    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(period)
    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_offset = nil)
      utc.respond_to?(:getlocal) ? utc.getlocal(utc_offset) : utc.to_time.getlocal(utc_offset)
    end
    alias_method :getlocal, :localtime

    # Returns true if the current time is within Daylight Savings Time for the
    # specified time zone.
    #
    #   Time.zone = 'Eastern Time (US & Canada)'    # => 'Eastern Time (US & Canada)'
    #   Time.zone.parse("2012-5-30").dst?           # => true
    #   Time.zone.parse("2012-11-30").dst?          # => false
    def dst?
      period.dst?
    end
    alias_method :isdst, :dst?

    # Returns true if the current time zone is set to UTC.
    #
    #   Time.zone = 'UTC'                           # => 'UTC'
    #   Time.zone.now.utc?                          # => true
    #   Time.zone = 'Eastern Time (US & Canada)'    # => 'Eastern Time (US & Canada)'
    #   Time.zone.now.utc?                          # => false
    def utc?
      time_zone.name == 'UTC'
    end
    alias_method :gmt?, :utc?

    # Returns the offset from current time to UTC time in seconds.
    def utc_offset
      period.utc_total_offset
    end
    alias_method :gmt_offset, :utc_offset
    alias_method :gmtoff, :utc_offset

    # Returns a formatted string of the offset from UTC, or an alternative
    # string if the time zone is already UTC.
    #
    #   Time.zone = 'Eastern Time (US & Canada)'   # => "Eastern Time (US & Canada)"
    #   Time.zone.now.formatted_offset(true)       # => "-05:00"
    #   Time.zone.now.formatted_offset(false)      # => "-0500"
    #   Time.zone = 'UTC'                          # => "UTC"
    #   Time.zone.now.formatted_offset(true, "0")  # => "0"
    def formatted_offset(colon = true, alternate_utc_string = nil)
      utc? && alternate_utc_string || TimeZone.seconds_to_utc_offset(utc_offset, colon)
    end

    # Returns the time zone abbreviation.
    #
    #   Time.zone = 'Eastern Time (US & Canada)'   # => "Eastern Time (US & Canada)"
    #   Time.zone.now.zone # => "EST"
    def zone
      period.zone_identifier.to_s
    end

    # Returns a string of the object's date, time, zone and offset from UTC.
    #
    #   Time.zone.now.httpdate  # => "Thu, 04 Dec 2014 11:00:25 EST -05:00"
    def inspect
      "#{time.strftime('%a, %d %b %Y %H:%M:%S')} #{zone} #{formatted_offset}"
    end

    # Returns a string of the object's date and time in the ISO 8601 standard
    # format.
    #
    #   Time.zone.now.xmlschema  # => "2014-12-04T11:02:37-05:00"
    def xmlschema(fraction_digits = 0)
      fraction = if fraction_digits.to_i > 0
        (".%06i" % time.usec)[0, fraction_digits.to_i + 1]
      end

      "#{time.strftime("%Y-%m-%dT%H:%M:%S")}#{fraction}#{formatted_offset(true, 'Z')}"
    end
    alias_method :iso8601, :xmlschema

    # Coerces time to a string for JSON encoding. The default format is ISO 8601.
    # You can get %Y/%m/%d %H:%M:%S +offset style by setting
    # <tt>ActiveSupport::JSON::Encoding.use_standard_json_time_format</tt>
    # to +false+.
    #
    #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = true
    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
    #   # => "2005-02-01T05:15:10.000-10:00"
    #
    #   # With ActiveSupport::JSON::Encoding.use_standard_json_time_format = false
    #   Time.utc(2005,2,1,15,15,10).in_time_zone("Hawaii").to_json
    #   # => "2005/02/01 05:15:10 -1000"
    def as_json(options = nil)
      if ActiveSupport::JSON::Encoding.use_standard_json_time_format
        xmlschema(ActiveSupport::JSON::Encoding.time_precision)
      else
        %(#{time.strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)})
      end
    end

    def encode_with(coder)
      if coder.respond_to?(:represent_object)
        coder.represent_object(nil, utc)
      else
        coder.represent_scalar(nil, utc.strftime("%Y-%m-%d %H:%M:%S.%9NZ"))
      end
    end

    # Returns a string of the object's date and time in the format used by
    # HTTP requests.
    #
    #   Time.zone.now.httpdate  # => "Tue, 01 Jan 2013 04:39:43 GMT"
    def httpdate
      utc.httpdate
    end

    # Returns a string of the object's date and time in the RFC 2822 standard
    # format.
    #
    #   Time.zone.now.rfc2822  # => "Tue, 01 Jan 2013 04:51:39 +0000"
    def rfc2822
      to_s(:rfc822)
    end
    alias_method :rfc822, :rfc2822

    # Returns a string of the object's date and time.
    # Accepts an optional <tt>format</tt>:
    # * <tt>:default</tt> - default value, mimics Ruby Time#to_s format.
    # * <tt>:db</tt> - format outputs time in UTC :db time. See Time#to_formatted_s(:db).
    # * Any key in <tt>Time::DATE_FORMATS</tt> can be used. See active_support/core_ext/time/conversions.rb.
    def to_s(format = :default)
      if format == :db
        utc.to_s(format)
      elsif 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 Time#to_s format
      end
    end
    alias_method :to_formatted_s, :to_s

    # Replaces <tt>%Z</tt> directive with +zone before passing to Time#strftime,
    # so that zone information is correct.
    def strftime(format)
      format = format.gsub(/((?:\A|[^%])(?:%%)*)%Z/, "\\1#{zone}")
      getlocal(utc_offset).strftime(format)
    end

    # Use the time in UTC for comparisons.
    def <=>(other)
      utc <=> other
    end

    # Returns true if the current object's time is within the specified
    # +min+ and +max+ time.
    def between?(min, max)
      utc.between?(min, max)
    end

    # Returns true if the current object's time is in the past.
    def past?
      utc.past?
    end

    # Returns true if the current object's time falls within
    # the current day.
    def today?
      time.today?
    end

    # Returns true if the current object's time is in the future.
    def future?
      utc.future?
    end

    def eql?(other)
      utc.eql?(other)
    end

    def hash
      utc.hash
    end

    # Adds an interval of time to the current object's time and return that
    # value as a new TimeWithZone object.
    #
    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
    #   now = Time.zone.now # => Sun, 02 Nov 2014 01:26:28 EDT -04:00
    #   now + 1000          # => Sun, 02 Nov 2014 01:43:08 EDT -04:00
    #
    # 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.
    #
    # For instance, a time + 24.hours will advance exactly 24 hours, while a
    # time + 1.day will advance 23-25 hours, depending on the day.
    #
    #   now + 24.hours      # => Mon, 03 Nov 2014 00:26:28 EST -05:00
    #   now + 1.day         # => Mon, 03 Nov 2014 01:26:28 EST -05:00
    def +(other)
      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
    alias_method :since, :+

    # Returns a new TimeWithZone object that represents the difference between
    # the current object's time and the +other+ time.
    #
    #   Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)'
    #   now = Time.zone.now # => Sun, 02 Nov 2014 01:26:28 EST -05:00
    #   now - 1000          # => Sun, 02 Nov 2014 01:09:48 EST -05:00
    #
    # If subtracting a Duration of variable length (i.e., years, months, days),
    # move backward from #time, otherwise move backward from #utc, for accuracy
    # when moving across DST boundaries.
    #
    # For instance, a time - 24.hours will go subtract exactly 24 hours, while a
    # time - 1.day will subtract 23-25 hours, depending on the day.
    #
    #   now - 24.hours      # => Sat, 01 Nov 2014 02:26:28 EDT -04:00
    #   now - 1.day         # => Sat, 01 Nov 2014 01:26:28 EDT -04:00
    def -(other)
      if other.acts_like?(:time)
        to_time - other.to_time
      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 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.values_at(:years, :weeks, :months, :days).any?
        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 usec nsec 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 to_a
      [time.sec, time.min, time.hour, time.day, time.mon, time.year, time.wday, time.yday, dst?, zone]
    end

    # Returns the object's date and time as a floating point number of seconds
    # since the Epoch (January 1, 1970 00:00 UTC).
    #
    #   Time.zone.now.to_f # => 1417709320.285418
    def to_f
      utc.to_f
    end

    # Returns the object's date and time as an integer number of seconds
    # since the Epoch (January 1, 1970 00:00 UTC).
    #
    #   Time.zone.now.to_i # => 1417709320
    def to_i
      utc.to_i
    end
    alias_method :tv_sec, :to_i

    # Returns the object's date and time as a rational number of seconds
    # since the Epoch (January 1, 1970 00:00 UTC).
    #
    #   Time.zone.now.to_r # => (708854548642709/500000)
    def to_r
      utc.to_r
    end

    # Return an instance of Time in the system timezone.
    def to_time
      utc.to_time
    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.find_zone(variables[1]), variables[2].utc)
    end

    # respond_to_missing? is not called in some cases, such as when type conversion is
    # performed with Kernel#String
    def respond_to?(sym, include_priv = false)
      # ensure that we're not going to throw and rescue from NoMethodError in method_missing which is slow
      return false if sym.to_sym == :to_str
      super
    end

    # Ensure proxy class responds to all methods that underlying time instance
    # responds to.
    def respond_to_missing?(sym, include_priv)
      # consistently respond false to acts_like?(:date), regardless of whether #time is a Time or DateTime
      return false if sym.to_sym == :acts_like_date?
      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)
      wrap_with_time_zone time.__send__(sym, *args, &block)
    rescue NoMethodError => e
      raise e, e.message.sub(time.inspect, self.inspect), e.backtrace
    end

    private
      def get_period_and_ensure_valid_local_time(period)
        # 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
          period || @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.year, time.month, time.day, time.hour, time.min, time.sec, Rational(time.nsec, 1000))
      end

      def duration_of_variable_length?(obj)
        ActiveSupport::Duration === obj && obj.parts.any? {|p| [:years, :months, :days].include?(p[0]) }
      end

      def wrap_with_time_zone(time)
        if time.acts_like?(:time)
          periods = time_zone.periods_for_local(time)
          self.class.new(nil, time_zone, time, periods.include?(period) ? period : nil)
        elsif time.is_a?(Range)
          wrap_with_time_zone(time.begin)..wrap_with_time_zone(time.end)
        else
          time
        end
      end
  end
end