From: Robert Klemme <bob.news@...>
Date: 2004-12-01T17:17:45+09:00
Subject: Re: Timezone Adjustment?


"zunda" <zunda616e@yahoo.co.jp> schrieb im Newsbeitrag
news:20041201053055.64878.qmail@web2305.mail.yahoo.co.jp...
> Hi,
>
> > "displaying"
> > the date/time from a database and justing it for the a users local
> > timezone in a web application.
> >
> > Is there a simple way of doing this?
>
> What I have been doing is to play with the environment variable TZ:
>
>   t = Time.now
>   ENV['TZ'] = 'HST'
>   puts t.localtime  #=> Tue Nov 30 19:25:55 HST 2004
>   ENV['TZ'] = 'Japan'
>   u = Time.at( t )
>   puts t.localtime  #=> Tue Nov 30 19:25:55 HST 2004
>   puts u.localtime  #=> Wed Dec 01 14:25:55 JST 2004
>
> It seems that we have to create a new Time object to change timezone.

Yeah, it seems so.

> I also like to know more sofisticated ways to do this.

Sounds like a candidate for an RCR.  Ideall we would like to have
Time#zone= (i.e. assignment).

It seems as if Time.utc and Time.local ignore the time zone argument (is
this a bug?).  Here are my tests:

09:16:05 [robert.klemme]: ruby /c/temp/ruby/times.rb
[6, 16, 10, 1, 12, 2004, 3, 336, false, "GMT+2:00"]
[6, 16, 10, 1, 12, 2004, 3, 336, false, "GMT+1:00"]
Wed Dec 01 10:16:06 GMT+2:00 2004
Wed Dec 01 10:16:06 GMT+2:00 2004
Wed Dec 01 10:16:06 UTC 2004
GMT+2:00
GMT+2:00
UTC
1101888966
1101888966
1101896166
-1101888966
0
-7200
09:16:06 [robert.klemme]: cat /c/temp/ruby/times.rb

t1 = Time.now
a = t1.to_a
p a
a[-1] = "GMT+1:00"
p a
t2 = Time.local(*a)
t3 = Time.utc(*a)

all = [t1,t2,t3]
puts all
puts all.map{|t| t.zone}
i = all.map{|t| t.to_i}
puts i
i.inject(0) {|last,t| puts last-t;t}

Kind regards

    robert