Class: Time

Relationships & Source Files
Inherits:	Object
Defined in:	lib/time.rb

Overview

time.rb

When 'time' is required, Time is extended with additional methods for parsing and converting Times.

Features

This library extends the Time class with the following conversions between date strings and Time objects:

date-time defined by RFC 2822
HTTP-date defined by RFC 2616
dateTime defined by XML Schema Part 2: Datatypes (ISO 8601)
various formats handled by Date._parse
custom formats handled by Date._strptime

Examples

All examples assume you have loaded Time with:

require 'time'

All of these examples were done using the EST timezone which is GMT-5.

Converting to a String

t = Time.now
t.iso8601  # => "2011-10-05T22:26:12-04:00"
t.rfc2822  # => "Wed, 05 Oct 2011 22:26:12 -0400"
t.httpdate # => "Thu, 06 Oct 2011 02:26:12 GMT"

.parse

#parse takes a string representation of a Time and attempts to parse it using a heuristic.

Time.parse("2010-10-31") #=> 2010-10-31 00:00:00 -0500

Any missing pieces of the date are inferred based on the current date.

# assuming the current date is "2011-10-31"
Time.parse("12:00") #=> 2011-10-31 12:00:00 -0500

We can change the date used to infer our missing elements by passing a second object that responds to #mon, #day and #year, such as Date, Time or DateTime. We can also use our own object.

class MyDate
  attr_reader :mon, :day, :year

  def initialize(mon, day, year)
    @mon, @day, @year = mon, day, year
  end
end

d  = Date.parse("2010-10-28")
t  = Time.parse("2010-10-29")
dt = DateTime.parse("2010-10-30")
md = MyDate.new(10,31,2010)

Time.parse("12:00", d)  #=> 2010-10-28 12:00:00 -0500
Time.parse("12:00", t)  #=> 2010-10-29 12:00:00 -0500
Time.parse("12:00", dt) #=> 2010-10-30 12:00:00 -0500
Time.parse("12:00", md) #=> 2010-10-31 12:00:00 -0500

#parse also accepts an optional block. You can use this block to specify how to handle the year component of the date. This is specifically designed for handling two digit years. For example, if you wanted to treat all two digit years prior to 70 as the year 2000+ you could write this:

Time.parse("01-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
#=> 2001-10-31 00:00:00 -0500
Time.parse("70-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
#=> 1970-10-31 00:00:00 -0500

.strptime

#strptime works similar to .parse except that instead of using a heuristic to detect the format of the input string, you provide a second argument that describes the format of the string. For example:

Time.strptime("2000-10-31", "%Y-%m-%d") #=> 2000-10-31 00:00:00 -0500

Class Method Summary

.apply_offset(year, mon, day, hour, min, sec, off)
.force_zone!(t, zone, offset = nil)
.httpdate(date)

Parses date as an HTTP-date defined by RFC 2616 and converts it to a Time object.
.iso8601(date)

Alias for .xmlschema.
.make_time(date, year, mon, day, hour, min, sec, sec_fraction, zone, now)
.month_days(y, m)
.parse(date, now = self.now)

Parses date using Date._parse and converts it to a Time object.
.rfc2822(date) (also: .rfc822)

Parses date as date-time defined by RFC 2822 and converts it to a Time object.
.rfc822(date)

Alias for .rfc2822.
.strptime(date, format, now = self.now)

Parses date using Date._strptime and converts it to a Time object.
.xmlschema(date) (also: .iso8601)

Parses date as a dateTime defined by the XML Schema and converts it to a Time object.
.zone_offset(zone, year = self.now.year)

Return the number of seconds the specified time zone differs from UTC.
.zone_utc?(zone) ⇒ Boolean

Instance Method Summary

#httpdate

Returns a string which represents the time as RFC 1123 date of HTTP-date defined by RFC 2616:
#iso8601(fraction_digits = 0)

Alias for #xmlschema.
#rfc2822 (also: #rfc822)

Returns a string which represents the time as date-time defined by RFC 2822:
#rfc822

Alias for #rfc2822.
#xmlschema(fraction_digits = 0) (also: #iso8601)

Returns a string which represents the time as a dateTime defined by XML Schema:

Class Method Details

.apply_offset(year, mon, day, hour, min, sec, off)

[ GitHub ]

# File 'lib/time.rb', line 208


def apply_offset(year, mon, day, hour, min, sec, off)
  if off < 0
    off = -off
    off, o = off.divmod(60)
    if o != 0 then sec += o; o, sec = sec.divmod(60); off += o end
    off, o = off.divmod(60)
    if o != 0 then min += o; o, min = min.divmod(60); off += o end
    off, o = off.divmod(24)
    if o != 0 then hour += o; o, hour = hour.divmod(24); off += o end
    if off != 0
      day += off
      days = month_days(year, mon)
      if days and days < day
        mon += 1
        if 12 < mon
          mon = 1
          year += 1
        end
        day = 1
      end
    end
  elsif 0 < off
    off, o = off.divmod(60)
    if o != 0 then sec -= o; o, sec = sec.divmod(60); off -= o end
    off, o = off.divmod(60)
    if o != 0 then min -= o; o, min = min.divmod(60); off -= o end
    off, o = off.divmod(24)
    if o != 0 then hour -= o; o, hour = hour.divmod(24); off -= o end
    if off != 0 then
      day -= off
      if day < 1
        mon -= 1
        if mon < 1
          year -= 1
          mon = 12
        end
        day = month_days(year, mon)
      end
    end
  end
  return year, mon, day, hour, min, sec
end

.force_zone!(t, zone, offset = nil)

[ GitHub ]

# File 'lib/time.rb', line 179


def force_zone!(t, zone, offset=nil)
  if zone_utc?(zone)
    t.utc
  elsif offset ||= zone_offset(zone)
    # Prefer the local timezone over the fixed offset timezone because
    # the former is a real timezone and latter is an artificial timezone.
    t.localtime
    if t.utc_offset != offset
      # Use the fixed offset timezone only if the local timezone cannot
      # represent the given offset.
      t.localtime(offset)
    end
  else
    t.localtime
  end
end

.httpdate(date)

Parses date as an HTTP-date defined by RFC 2616 and converts it to a Time object.

ArgumentError is raised if date is not compliant with RFC 2616 or if the Time class cannot represent specified date.

See #httpdate for more information on this format.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 523


def httpdate(date)
  if /\A\s*
      (?:Mon|Tue|Wed|Thu|Fri|Sat|Sun),\x20
      (\d{2})\x20
      (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\x20
      (\d{4})\x20
      (\d{2}):(\d{2}):(\d{2})\x20
      GMT
      \s*\z/ix =~ date
    self.rfc2822(date).utc
  elsif /\A\s*
         (?:Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday),\x20
         (\d\d)-(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)-(\d\d)\x20
         (\d\d):(\d\d):(\d\d)\x20
         GMT
         \s*\z/ix =~ date
    year = $3.to_i
    if year < 50
      year += 2000
    else
      year += 1900
    end
    self.utc(year, $2, $1.to_i, $4.to_i, $5.to_i, $6.to_i)
  elsif /\A\s*
         (?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)\x20
         (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\x20
         (\d\d|\x20\d)\x20
         (\d\d):(\d\d):(\d\d)\x20
         (\d{4})
         \s*\z/ix =~ date
    self.utc($6.to_i, MonthValue[$1.upcase], $2.to_i,
             $3.to_i, $4.to_i, $5.to_i)
  else
    raise ArgumentError.new("not RFC 2616 compliant date: #{date.inspect}")
  end
end

.iso8601(date)

Alias for .xmlschema.

[ GitHub ]

# File 'lib/time.rb', line 605


alias iso8601 xmlschema

.make_time(date, year, mon, day, hour, min, sec, sec_fraction, zone, now)

[ GitHub ]

# File 'lib/time.rb', line 252


def make_time(date, year, mon, day, hour, min, sec, sec_fraction, zone, now)
  if !year && !mon && !day && !hour && !min && !sec && !sec_fraction
    raise ArgumentError, "no time information in #{date.inspect}"
  end

  off = nil
  if year || now
    off_year = year || now.year
    off = zone_offset(zone, off_year) if zone
  end

  if now
    if off
      now = now.getlocal(off) if now.utc_offset != off
    else
      now = now.getlocal
    end
  end

  usec = nil
  usec = sec_fraction * 1000000 if sec_fraction

  if now
    begin
      break if year; year = now.year
      break if mon; mon = now.mon
      break if day; day = now.day
      break if hour; hour = now.hour
      break if min; min = now.min
      break if sec; sec = now.sec
      break if sec_fraction; usec = now.tv_usec
    end until true
  end

  year ||= 1970
  mon ||= 1
  day ||= 1
  hour ||= 0
  min ||= 0
  sec ||= 0
  usec ||= 0

  if year != off_year
    off = nil
    off = zone_offset(zone, year) if zone
  end

  if off
    year, mon, day, hour, min, sec =
      apply_offset(year, mon, day, hour, min, sec, off)
    t = self.utc(year, mon, day, hour, min, sec, usec)
    force_zone!(t, zone, off)
    t
  else
    self.local(year, mon, day, hour, min, sec, usec)
  end
end

.month_days(y, m)

[ GitHub ]

# File 'lib/time.rb', line 199


def month_days(y, m)
  if ((y % 4 == 0) && (y % 100 != 0)) || (y % 400 == 0)
    LeapYearMonthDays[m-1]
  else
    CommonYearMonthDays[m-1]
  end
end

.parse(date, now = self.now)

Parses date using Date._parse and converts it to a Time object.

If a block is given, the year described in date is converted by the block. For example:

Time.parse(...) {|y| 0 <= y && y < 100 ? (y >= 69 ? y + 1900 : y + 2000) : y}

If the upper components of the given time are broken or missing, they are supplied with those of now. For the lower components, the minimum values (1 or 0) are assumed if broken or missing. For example:

# Suppose it is "Thu Nov 29 14:33:20 2001" now and
# your time zone is EST which is GMT-5.
now = Time.parse("Thu Nov 29 14:33:20 2001")
Time.parse("16:30", now)     #=> 2001-11-29 16:30:00 -0500
Time.parse("7/23", now)      #=> 2001-07-23 00:00:00 -0500
Time.parse("Aug 31", now)    #=> 2001-08-31 00:00:00 -0500
Time.parse("Aug 2000", now)  #=> 2000-08-01 00:00:00 -0500

Since there are numerous conflicts among locally defined time zone abbreviations all over the world, this method is not intended to understand all of them. For example, the abbreviation “CST” is used variously as:

-06:00 in America/Chicago,
-05:00 in America/Havana,
+08:00 in Asia/Harbin,
+09:30 in Australia/Darwin,
+10:30 in Australia/Adelaide,
etc.

Based on this fact, this method only understands the time zone abbreviations described in RFC 822 and the system time zone, in the order named. (i.e. a definition in RFC 822 overrides the system time zone definition.) The system time zone is taken from Time.local(year, 1, 1).zone and Time.local(year, 7, 1).zone. If the extracted time zone abbreviation does not match any of them, it is ignored and the given time is regarded as a local time.

ArgumentError is raised if Date._parse cannot extract information from date or if the Time class cannot represent specified date.

This method can be used as a fail-safe for other parsing methods as:

Time.rfc2822(date) rescue Time.parse(date)
Time.httpdate(date) rescue Time.parse(date)
Time.xmlschema(date) rescue Time.parse(date)

A failure of parse should be checked, though.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 365


def parse(date, now=self.now)
  comp = !block_given?
  d = Date._parse(date, comp)
  year = d[:year]
  year = yield(year) if year && !comp
  make_time(date, year, d[:mon], d[:mday], d[:hour], d[:min], d[:sec], d[:sec_fraction], d[:zone], now)
end

.rfc2822(date) Also known as: .rfc822

Parses date as date-time defined by RFC 2822 and converts it to a Time object. The format is identical to the date format defined by RFC 822 and updated by RFC 1123.

ArgumentError is raised if date is not compliant with RFC 2822 or if the Time class cannot represent specified date.

See #rfc2822 for more information on this format.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 470


def rfc2822(date)
  if /\A\s*
      (?:(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)\s*,\s*)?
      (\d{1,2})\s+
      (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s+
      (\d{2,})\s+
      (\d{2})\s*
      :\s*(\d{2})\s*
      (?::\s*(\d{2}))?\s+
      ([+-]\d{4}|
       UT|GMT|EST|EDT|CST|CDT|MST|MDT|PST|PDT|[A-IK-Z])/ix =~ date
    # Since RFC 2822 permit comments, the regexp has no right anchor.
    day = $1.to_i
    mon = MonthValue[$2.upcase]
    year = $3.to_i
    short_year_p = $3.length <= 3
    hour = $4.to_i
    min = $5.to_i
    sec = $6 ? $6.to_i : 0
    zone = $7

    if short_year_p
      # following year completion is compliant with RFC 2822.
      year = if year < 50
               2000 + year
             else
               1900 + year
             end
    end

    off = zone_offset(zone)
    year, mon, day, hour, min, sec =
      apply_offset(year, mon, day, hour, min, sec, off)
    t = self.utc(year, mon, day, hour, min, sec)
    force_zone!(t, zone, off)
    t
  else
    raise ArgumentError.new("not RFC 2822 compliant date: #{date.inspect}")
  end
end

.rfc822(date)

Alias for .rfc2822.

[ GitHub ]

# File 'lib/time.rb', line 510


alias rfc822 rfc2822

.strptime(date, format, now = self.now)

Parses date using Date._strptime and converts it to a Time object.

If a block is given, the year described in date is converted by the block. For example:

Time.strptime(...) {|y| y < 100 ? (y >= 69 ? y + 1900 : y + 2000) : y}

Below is a list of the formatting options:

%a

The abbreviated weekday name (“Sun”)

%A

The full weekday name (“Sunday”)

%b

The abbreviated month name (“Jan”)

%B

The full month name (“January”)

%c

The preferred local date and time representation

%C

Century (20 in 2009)

%d

Day of the month (01..31)

%D

Date (%m/%d/%y)

%e

Day of the month, blank-padded ( 1..31)

%F

Equivalent to %Y-%m-%d (the ISO 8601 date format)

%h

Equivalent to %b

%H

Hour of the day, 24-hour clock (00..23)

%I

Hour of the day, 12-hour clock (01..12)

%j

Day of the year (001..366)

%k

hour, 24-hour clock, blank-padded ( 0..23)

%l

hour, 12-hour clock, blank-padded ( 0..12)

%L

Millisecond of the second (000..999)

%m

Month of the year (01..12)

%M

Minute of the hour (00..59)

%n

Newline (n)

%N

Fractional seconds digits, default is 9 digits (nanosecond)

%3N: millisecond (3 digits)
%6N: microsecond (6 digits)
%9N: nanosecond (9 digits)

%p

Meridian indicator (“AM” or “PM”)

%P

Meridian indicator (“am” or “pm”)

%r

time, 12-hour (same as %I:%M:%S %p)

%R

time, 24-hour (%H:%M)

%s

Number of seconds since 1970-01-01 00:00:00 UTC.

%S

Second of the minute (00..60)

%t

Tab character (t)

%T

time, 24-hour (%H:%M:%S)

%u

Day of the week as a decimal, Monday being 1. (1..7)

%U

Week number of the current year, starting with the first Sunday as the first day of the first week (00..53)

%v

VMS date (%e-%b-%Y)

%V

Week number of year according to ISO 8601 (01..53)

%W

Week number of the current year, starting with the first Monday as the first day of the first week (00..53)

%w

Day of the week (Sunday is 0, 0..6)

%x

Preferred representation for the date alone, no time

%X

Preferred representation for the time alone, no date

%y

Year without a century (00..99)

%Y

Year which may include century, if provided

%z

Time zone as hour offset from UTC (e.g. +0900)

%Z

Time zone name

%%

Literal “%” character

Raises:

(ArgumentError)

[ GitHub ]

# File 'lib/time.rb', line 431


def strptime(date, format, now=self.now)
  d = Date._strptime(date, format)
  raise ArgumentError, "invalid strptime format - `#{format}'" unless d
  if seconds = d[:seconds]
    if sec_fraction = d[:sec_fraction]
      usec = sec_fraction * 1000000
      usec *= -1 if seconds < 0
    else
      usec = 0
    end
    t = Time.at(seconds, usec)
    if zone = d[:zone]
      force_zone!(t, zone)
    end
  else
    year = d[:year]
    year = yield(year) if year && block_given?
    t = make_time(date, year, d[:mon], d[:mday], d[:hour], d[:min], d[:sec], d[:sec_fraction], d[:zone], now)
  end
  t
end

.xmlschema(date) Also known as: .iso8601

Parses date as a dateTime defined by the XML Schema and converts it to a Time object. The format is a restricted version of the format defined by ISO 8601.

ArgumentError is raised if date is not compliant with the format or if the Time class cannot represent specified date.

See #xmlschema for more information on this format.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 572


def xmlschema(date)
  if /\A\s*
      (-?\d+)-(\d\d)-(\d\d)
      T
      (\d\d):(\d\d):(\d\d)
      (\.\d+)?
      (Z|[+-]\d\d(?::?\d\d)?)?
      \s*\z/ix =~ date
    year = $1.to_i
    mon = $2.to_i
    day = $3.to_i
    hour = $4.to_i
    min = $5.to_i
    sec = $6.to_i
    usec = 0
    if $7
      usec = Rational($7) * 1000000
    end
    if $8
      zone = $8
      off = zone_offset(zone)
      year, mon, day, hour, min, sec =
        apply_offset(year, mon, day, hour, min, sec, off)
      t = self.utc(year, mon, day, hour, min, sec, usec)
      force_zone!(t, zone, off)
      t
    else
      self.local(year, mon, day, hour, min, sec, usec)
    end
  else
    raise ArgumentError.new("invalid date: #{date.inspect}")
  end
end

.zone_offset(zone, year = self.now.year)

Return the number of seconds the specified time zone differs from UTC.

Numeric time zones that include minutes, such as -10:00 or +1330 will work, as will simpler hour-only time zones like -10 or +13.

Textual time zones listed in ZoneOffset are also supported.

If the time zone does not match any of the above, zone_offset will check if the local time zone (both with and without potential Daylight Saving Time changes being in effect) matches zone. Specifying a value for year will change the year used to find the local time zone.

If zone_offset is unable to determine the offset, nil will be returned.

[ GitHub ]

# File 'lib/time.rb', line 134


def zone_offset(zone, year=self.now.year)
  off = nil
  zone = zone.upcase
  if /\A([+-])(\d\d):?(\d\d)\z/ =~ zone
    off = ($1 == '-' ? -1 : 1) * ($2.to_i * 60 + $3.to_i) * 60
  elsif /\A[+-]\d\d\z/ =~ zone
    off = zone.to_i * 3600
  elsif ZoneOffset.include?(zone)
    off = ZoneOffset[zone] * 3600
  elsif ((t = self.local(year, 1, 1)).zone.upcase == zone rescue false)
    off = t.utc_offset
  elsif ((t = self.local(year, 7, 1)).zone.upcase == zone rescue false)
    off = t.utc_offset
  end
  off
end

.zone_utc?(zone) ⇒ `Boolean`

[ GitHub ]

# File 'lib/time.rb', line 151


def zone_utc?(zone)
  # * +0000
  #   In RFC 2822, +0000 indicate a time zone at Universal Time.
  #   Europe/Lisbon is "a time zone at Universal Time" in Winter.
  #   Atlantic/Reykjavik is "a time zone at Universal Time".
  #   Africa/Dakar is "a time zone at Universal Time".
  #   So +0000 is a local time such as Europe/London, etc.
  # * GMT
  #   GMT is used as a time zone abbreviation in Europe/London,
  #   Africa/Dakar, etc.
  #   So it is a local time.
  #
  # * -0000, -00:00
  #   In RFC 2822, -0000 the date-time contains no information about the
  #   local time zone.
  #   In RFC 3339, -00:00 is used for the time in UTC is known,
  #   but the offset to local time is unknown.
  #   They are not appropriate for specific time zone such as
  #   Europe/London because time zone neutral,
  #   So -00:00 and -0000 are treated as UTC.
  if /\A(?:-00:00|-0000|-00|UTC|Z|UT)\z/i =~ zone
    true
  else
    false
  end
end

Instance Method Details

#httpdate

Returns a string which represents the time as RFC 1123 date of HTTP-date defined by RFC 2616:

day-of-week, DD month-name CCYY hh:mm:ss GMT

Note that the result is always UTC (GMT).

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 654


def httpdate
  t = dup.utc
  sprintf('%s, %02d %s %0*d %02d:%02d:%02d GMT',
    RFC2822_DAY_NAME[t.wday],
    t.day, RFC2822_MONTH_NAME[t.mon-1], t.year < 0 ? 5 : 4, t.year,
    t.hour, t.min, t.sec)
end

#iso8601(fraction_digits = 0)

Alias for #xmlschema.

[ GitHub ]

# File 'lib/time.rb', line 686


alias iso8601 xmlschema

#rfc2822 Also known as: #rfc822

Returns a string which represents the time as date-time defined by RFC 2822:

day-of-week, DD month-name CCYY hh:mm:ss zone

where zone is [+-]hhmm.

If self is a UTC time, -0000 is used as zone.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 619


def rfc2822
  sprintf('%s, %02d %s %0*d %02d:%02d:%02d ',
    RFC2822_DAY_NAME[wday],
    day, RFC2822_MONTH_NAME[mon-1], year < 0 ? 5 : 4, year,
    hour, min, sec) <<
  if utc?
    '-0000'
  else
    off = utc_offset
    sign = off < 0 ? '-' : '+'
    sprintf('%s%02d%02d', sign, *(off.abs / 60).divmod(60))
  end
end

#rfc822

Alias for #rfc2822.

[ GitHub ]

# File 'lib/time.rb', line 632


alias rfc822 rfc2822

#xmlschema(fraction_digits = 0) Also known as: #iso8601

Returns a string which represents the time as a dateTime defined by XML Schema:

CCYY-MM-DDThh:mm:ssTZD
CCYY-MM-DDThh:mm:ss.sssTZD

where TZD is Z or [+-]hh:mm.

If self is a UTC time, Z is used as TZD. [+-]hh:mm is used otherwise.

fractional_digits specifies a number of digits to use for fractional seconds. Its default value is 0.

You must require 'time' to use this method.

[ GitHub ]

# File 'lib/time.rb', line 678


def xmlschema(fraction_digits=0)
  fraction_digits = fraction_digits.to_i
  s = strftime("%FT%T")
  if fraction_digits > 0
    s << strftime(".%#{fraction_digits}N")
  end
  s << (utc? ? 'Z' : strftime("%:z"))
end

Class: Time

Overview

time.rb

Features

Examples

Converting to a String

.parse

.strptime

Class Method Summary

Instance Method Summary

Class Method Details

.apply_offset(year, mon, day, hour, min, sec, off)

.force_zone!(t, zone, offset = nil)

.httpdate(date)

.iso8601(date)

.make_time(date, year, mon, day, hour, min, sec, sec_fraction, zone, now)

.month_days(y, m)

.parse(date, now = self.now)

.rfc2822(date) Also known as: .rfc822

.rfc822(date)

.strptime(date, format, now = self.now)

.xmlschema(date) Also known as: .iso8601

.zone_offset(zone, year = self.now.year)

.zone_utc?(zone) ⇒ Boolean

Instance Method Details

#httpdate

#iso8601(fraction_digits = 0)

#rfc2822 Also known as: #rfc822

#rfc822

#xmlschema(fraction_digits = 0) Also known as: #iso8601

.zone_utc?(zone) ⇒ `Boolean`