Rails - Mar 2006 - TimeZone, TZInfo, daylight savings, and composed_of

Does anyone know the best way to track time zone information.  There
doesn''t
seem to be much documentation on this.  So far it seems like a simple db
field like

create table accounts (
  id                int unsigned not null auto_increment,
  name          varchar(50) not null,
  time_zone   varchar(50) not null,
  ...
  primary key (id)
)

and a class like

class Account < AR
  ...
  composed_of :time_zone, :class_name => TimeZone, :mapping =>
%w(time_zone
name)
end

There also seems to be a TZInfo library that supports daylight savings.  It
seems strange that the TimeZone class in rails doesn''t support daylight
savings as Basecamp from 37Signals uses timezones and I''m sure they
would
have to support it... interesting.

Can anyone shed some light on this. :)

Thanks,
Zack
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I don''t know if this helps much, but that''s basically what
I''m doing, and it
seems to work.  Doing the timezone conversions is a pain, but it works.
It''s also kinda slow :(

On 3/16/06, Zack Chandler <zackchandler@gmail.com>
wrote:
>
> Does anyone know the best way to track time zone information.  There
> doesn''t seem to be much documentation on this.  So far it seems
like a
> simple db field like
>
> create table accounts (
>   id                int unsigned not null auto_increment,
>   name          varchar(50) not null,
>   time_zone   varchar(50) not null,
>   ...
>   primary key (id)
> )
>
> and a class like
>
> class Account < AR
>   ...
>   composed_of :time_zone, :class_name => TimeZone, :mapping =>
> %w(time_zone name)
> end
>
> There also seems to be a TZInfo library that supports daylight savings.
> It seems strange that the TimeZone class in rails doesn''t support
daylight
> savings as Basecamp from 37Signals uses timezones and I''m sure
they would
> have to support it... interesting.
>
> Can anyone shed some light on this. :)
>
> Thanks,
> Zack
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>
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The Pragmatic Rails Recipes book includes:

Recipe 23: Dealing With Time-zones

--  
-- Tom Mornini

On Mar 16, 2006, at 9:06 AM, Michael Smedberg wrote:
> I don''t know if this helps much, but that''s basically
what I''m
> doing, and it seems to work.  Doing the timezone conversions is a  
> pain, but it works.  It''s also kinda slow :(
>
> On 3/16/06, Zack Chandler <zackchandler@gmail.com> wrote:
> Does anyone know the best way to track time zone information.   
> There doesn''t seem to be much documentation on this.  So far it  
> seems like a simple db field like
>
> create table accounts (
>   id                int unsigned not null auto_increment,
>   name          varchar(50) not null,
>   time_zone   varchar(50) not null,
>   ...
>   primary key (id)
> )
>
> and a class like
>
> class Account < AR
>   ...
>   composed_of :time_zone, :class_name => TimeZone, :mapping => %w 
> (time_zone name)
> end
>
> There also seems to be a TZInfo library that supports daylight  
> savings.  It seems strange that the TimeZone class in rails
doesn''t
> support daylight savings as Basecamp from 37Signals uses timezones  
> and I''m sure they would have to support it... interesting.
>
> Can anyone shed some light on this. :)
>
> Thanks,
> Zack
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
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Thanks Tom - I''ll check it out.

On 3/16/06, Tom Mornini <tmornini@infomania.com>
wrote:
>
> The Pragmatic Rails Recipes book includes:
> Recipe 23: Dealing With Time-zones
>
> --
> -- Tom Mornini
>
> On Mar 16, 2006, at 9:06 AM, Michael Smedberg wrote:
>
> I don''t know if this helps much, but that''s basically
what I''m doing, and
> it seems to work.  Doing the timezone conversions is a pain, but it works.
> It''s also kinda slow :(
>
> On 3/16/06, Zack Chandler <zackchandler@gmail.com> wrote:
> >
> > Does anyone know the best way to track time zone information.  There
> > doesn''t seem to be much documentation on this.  So far it
seems like a
> > simple db field like
> >
> > create table accounts (
> >   id                int unsigned not null auto_increment,
> >   name          varchar(50) not null,
> >   time_zone   varchar(50) not null,
> >   ...
> >   primary key (id)
> > )
> >
> > and a class like
> >
> > class Account < AR
> >   ...
> >   composed_of :time_zone, :class_name => TimeZone, :mapping =>
> > %w(time_zone name)
> > end
> >
> > There also seems to be a TZInfo library that supports daylight
savings.
> > It seems strange that the TimeZone class in rails doesn''t
support daylight
> > savings as Basecamp from 37Signals uses timezones and I''m
sure they would
> > have to support it... interesting.
> >
> > Can anyone shed some light on this. :)
> >
> > Thanks,
> > Zack
> >
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
> >
> >
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>
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For what it''s worth (I haven''t read the book), here''s
my way of
handling timezones using TZinfo... Extra stuff such as relationships
and so on removed for clarity.

--snip--
require_gem ''tzinfo''
class Timezone < ActiveRecord::Base
  extend Forwardable

  validates_presence_of   :name, :display_name

  validates_each :name do |record, attribute|
    unless TZInfo::Timezone.get(self.name)
      record.errors.add attribute, "Invalid Timezone"
    end
  end

  # Forward these methods to the TZInfo::Timezone class
  def_delegator(:tz, :utc_to_local, :utc_to_local)
  def_delegator(:tz, :local_to_utc, :local_to_utc)
  def_delegator(:tz, :identifier,   :identifier)
  # End forward

  def name=(value)
    write_attribute(:name, value)
    @tz = nil
  end

  def now
    tz().now()
  end

  def today
    Date.parse(now().strftime(DATEFORMAT_YYYYMMDD))
  end

  private

  # This method caches the TZInfo::Timezone class unless it is
  # flushed by the +name=+ method above.
  def tz()
    @tz.nil? ? @tz = TZInfo::Timezone.get(self.name) : @tz
  end

end
--/snip--

Cheers,
Dan
www.peoplehub.com.au

Thanks for sharing the code Dan!

On 3/16/06, Dan Sketcher <dansketcher@gmail.com>
wrote:
>
> For what it''s worth (I haven''t read the book),
here''s my way of
> handling timezones using TZinfo... Extra stuff such as relationships
> and so on removed for clarity.
>
> --snip--
> require_gem ''tzinfo''
> class Timezone < ActiveRecord::Base
>   extend Forwardable
>
>   validates_presence_of   :name, :display_name
>
>   validates_each :name do |record, attribute|
>     unless TZInfo::Timezone.get(self.name)
>       record.errors.add attribute, "Invalid Timezone"
>     end
>   end
>
>   # Forward these methods to the TZInfo::Timezone class
>   def_delegator(:tz, :utc_to_local, :utc_to_local)
>   def_delegator(:tz, :local_to_utc, :local_to_utc)
>   def_delegator(:tz, :identifier,   :identifier)
>   # End forward
>
>   def name=(value)
>     write_attribute(:name, value)
>     @tz = nil
>   end
>
>   def now
>     tz().now()
>   end
>
>   def today
>     Date.parse(now().strftime(DATEFORMAT_YYYYMMDD))
>   end
>
>   private
>
>   # This method caches the TZInfo::Timezone class unless it is
>   # flushed by the +name=+ method above.
>   def tz()
>     @tz.nil? ? @tz = TZInfo::Timezone.get(self.name) : @tz
>   end
>
> end
> --/snip--
>
> Cheers,
> Dan
> www.peoplehub.com.au
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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