class CoreExt::TimeZone
The TimeZone
class serves as a wrapper around TZInfo::Timezone instances. It allows us to do the following:
-
Limit the set of zones provided by TZInfo to a meaningful subset of 146 zones.
-
Retrieve and display zones with a friendlier name (e.g., “Eastern
Time
(US & Canada)” instead of “America/New_York”). -
Lazily load TZInfo::Timezone instances only when they're needed.
-
Create
CoreExt::TimeWithZone
instances via TimeZone'slocal
,parse
,at
andnow
methods.
If you set config.time_zone
in the Rails Application, you can access this TimeZone
object via Time.zone
:
# application.rb: class Application < Rails::Application config.time_zone = 'Eastern Time (US & Canada)' end Time.zone # => #<CoreExt::TimeZone:0x514834...> Time.zone.name # => "Eastern Time (US & Canada)" Time.zone.now # => Sun, 18 May 2008 14:30:44 EDT -04:00
Constants
- MAPPING
Keys are Rails
TimeZone
names, values are TZInfo identifiers.- UTC_OFFSET_WITHOUT_COLON
- UTC_OFFSET_WITH_COLON
Attributes
Public Class Methods
Locate a specific time zone object. If the argument is a string, it is interpreted to mean the name of the timezone to locate. If it is a numeric value it is either the hour offset, or the second offset, of the timezone to find. (The first one with that offset will be returned.) Returns nil
if no such time zone is known to the system.
# File lib/core_ext/time_zone.rb, line 226 def [](arg) case arg when String begin @lazy_zones_map[arg] ||= create(arg) rescue TZInfo::InvalidTimezoneIdentifier nil end when Numeric, CoreExt::Duration arg *= 3600 if arg.abs <= 13 all.find { |z| z.utc_offset == arg.to_i } else raise ArgumentError, "invalid argument to TimeZone[]: #{arg.inspect}" end end
# File lib/core_ext/time_zone.rb, line 201 def find_tzinfo(name) TZInfo::Timezone.new(MAPPING[name] || name) end
Returns a TimeZone
instance with the given name, or nil
if no such TimeZone
instance exists. (This exists to support the use of this class with the composed_of
macro.)
# File lib/core_ext/time_zone.rb, line 210 def new(name) self[name] end
Create a new TimeZone
object with the given name and offset. The offset is the number of seconds that this time zone is offset from UTC (GMT). Seconds were chosen as the offset unit because that is the unit that Ruby uses to represent time zone offsets (see Time#utc_offset).
# File lib/core_ext/time_zone.rb, line 265 def initialize(name, utc_offset = nil, tzinfo = nil) @name = name @utc_offset = utc_offset @tzinfo = tzinfo || TimeZone.find_tzinfo(name) @current_period = nil end
Assumes self represents an offset from UTC in seconds (as returned from Time#utc_offset) and turns this into an +HH:MM formatted string.
CoreExt::TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"
# File lib/core_ext/time_zone.rb, line 193 def seconds_to_utc_offset(seconds, colon = true) format = colon ? UTC_OFFSET_WITH_COLON : UTC_OFFSET_WITHOUT_COLON sign = (seconds < 0 ? '-' : '+') hours = seconds.abs / 3600 minutes = (seconds.abs % 3600) / 60 format % [sign, hours, minutes] end
A convenience method for returning a collection of TimeZone
objects for time zones in the USA.
# File lib/core_ext/time_zone.rb, line 244 def us_zones @us_zones ||= all.find_all { |z| z.name =~ /US|Arizona|Indiana|Hawaii|Alaska/ } end
Private Class Methods
# File lib/core_ext/time_zone.rb, line 249 def zones_map @zones_map ||= begin MAPPING.each_key {|place| self[place]} # load all the zones @lazy_zones_map end end
Public Instance Methods
Compare this time zone to the parameter. The two are compared first on their offsets, and then by name.
# File lib/core_ext/time_zone.rb, line 294 def <=>(zone) return unless zone.respond_to? :utc_offset result = (utc_offset <=> zone.utc_offset) result = (name <=> zone.name) if result == 0 result end
Compare name
and TZInfo identifier to a supplied regexp, returning true
if a match is found.
# File lib/core_ext/time_zone.rb, line 303 def =~(re) re === name || re === MAPPING[name] end
Method
for creating new CoreExt::TimeWithZone
instance in time zone of self
from number of seconds since the Unix epoch.
Time.zone = 'Hawaii' # => "Hawaii" Time.utc(2000).to_f # => 946684800.0 Time.zone.at(946684800.0) # => Fri, 31 Dec 1999 14:00:00 HST -10:00
# File lib/core_ext/time_zone.rb, line 328 def at(secs) Time.at(secs).utc.in_time_zone(self) end
Returns a formatted string of the offset from UTC, or an alternative string if the time zone is already UTC.
zone = CoreExt::TimeZone['Central Time (US & Canada)'] zone.formatted_offset # => "-06:00" zone.formatted_offset(false) # => "-0600"
# File lib/core_ext/time_zone.rb, line 288 def formatted_offset(colon=true, alternate_utc_string = nil) utc_offset == 0 && alternate_utc_string || self.class.seconds_to_utc_offset(utc_offset, colon) end
Method
for creating new CoreExt::TimeWithZone
instance in time zone of self
from given values.
Time.zone = 'Hawaii' # => "Hawaii" Time.zone.local(2007, 2, 1, 15, 30, 45) # => Thu, 01 Feb 2007 15:30:45 HST -10:00
# File lib/core_ext/time_zone.rb, line 317 def local(*args) time = Time.utc(*args) CoreExt::TimeWithZone.new(nil, self, time) end
Adjust the given time to the simultaneous time in UTC. Returns a Time.utc() instance.
# File lib/core_ext/time_zone.rb, line 409 def local_to_utc(time, dst=true) tzinfo.local_to_utc(time, dst) end
Returns an CoreExt::TimeWithZone
instance representing the current time in the time zone represented by self
.
Time.zone = 'Hawaii' # => "Hawaii" Time.zone.now # => Wed, 23 Jan 2008 20:24:27 HST -10:00
# File lib/core_ext/time_zone.rb, line 381 def now time_now.utc.in_time_zone(self) end
Method
for creating new CoreExt::TimeWithZone
instance in time zone of self
from parsed string.
Time.zone = 'Hawaii' # => "Hawaii" Time.zone.parse('1999-12-31 14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
If upper components are missing from the string, they are supplied from TimeZone#now
:
Time.zone.now # => Fri, 31 Dec 1999 14:00:00 HST -10:00 Time.zone.parse('22:30:00') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
However, if the date component is not provided, but any other upper components are supplied, then the day of the month defaults to 1:
Time.zone.parse('Mar 2000') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
# File lib/core_ext/time_zone.rb, line 348 def parse(str, now=now()) parts_to_time(Date._parse(str, false), now) end
Available so that TimeZone
instances respond like TZInfo::Timezone instances. github.com/tzinfo/tzinfo/issues/32
# File lib/core_ext/time_zone.rb, line 422 def period_for_local(time, dst=true) tzinfo.period_for_local(time, dst) { |results| results.first } end
Available so that TimeZone
instances respond like TZInfo::Timezone instances.
# File lib/core_ext/time_zone.rb, line 415 def period_for_utc(time) tzinfo.period_for_utc(time) end
Parses str
according to format
and returns an CoreExt::TimeWithZone
.
Assumes that str
is a time in the time zone self
, unless format
includes an explicit time zone. (This is the same behavior as parse
.) In either case, the returned TimeWithZone
has the timezone of self
.
Time.zone = 'Hawaii' # => "Hawaii" Time.zone.strptime('1999-12-31 14:00:00', '%Y-%m-%d %H:%M:%S') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
If upper components are missing from the string, they are supplied from TimeZone#now
:
Time.zone.now # => Fri, 31 Dec 1999 14:00:00 HST -10:00 Time.zone.strptime('22:30:00', '%H:%M:%S') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
However, if the date component is not provided, but any other upper components are supplied, then the day of the month defaults to 1:
Time.zone.strptime('Mar 2000', '%b %Y') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
# File lib/core_ext/time_zone.rb, line 372 def strptime(str, format, now=now()) parts_to_time(DateTime._strptime(str, format), now) end
Returns a textual representation of this time zone.
# File lib/core_ext/time_zone.rb, line 308 def to_s "(GMT#{formatted_offset}) #{name}" end
Returns the current date in this time zone.
# File lib/core_ext/time_zone.rb, line 386 def today tzinfo.now.to_date end
Returns the next date in this time zone.
# File lib/core_ext/time_zone.rb, line 391 def tomorrow today + 1 end
Returns the offset of this time zone from UTC in seconds.
# File lib/core_ext/time_zone.rb, line 273 def utc_offset if @utc_offset @utc_offset else @current_period ||= tzinfo.current_period if tzinfo @current_period.utc_offset if @current_period end end
Adjust the given time to the simultaneous time in the time zone represented by self
. Returns a Time.utc() instance – if you want an CoreExt::TimeWithZone
instance, use Time#in_time_zone()
instead.
# File lib/core_ext/time_zone.rb, line 403 def utc_to_local(time) tzinfo.utc_to_local(time) end
Returns the previous date in this time zone.
# File lib/core_ext/time_zone.rb, line 396 def yesterday today - 1 end
Private Instance Methods
# File lib/core_ext/time_zone.rb, line 440 def parts_to_time(parts, now) return if parts.empty? time = Time.new( parts.fetch(:year, now.year), parts.fetch(:mon, now.month), parts.fetch(:mday, parts[:year] || parts[:mon] ? 1 : now.day), parts.fetch(:hour, 0), parts.fetch(:min, 0), parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0), parts.fetch(:offset, 0) ) if parts[:offset] TimeWithZone.new(time.utc, self) else TimeWithZone.new(nil, self, time) end end
# File lib/core_ext/time_zone.rb, line 460 def time_now Time.now end