# Rails 2.1 Timezone Support

**URL:** <https://www.ruby-forum.com/t/rails-2-1-timezone-support/148330>\
**Category:** Rails\
**Created:** [September 11, 2008, 7:13pm UTC](https://www.ruby-forum.com/t/rails-2-1-timezone-support/148330 "2008-09-11T19:13:03Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [September 11, 2008, 7:13pm UTC](https://www.ruby-forum.com/t/rails-2-1-timezone-support/148330/1 "2008-09-11T19:13:03Z")

</div>

I understand the basics of timezone support:

> **[Mad Mimi Email Marketing](https://madmimi.com)**
>
> Mad Mimi makes it simple to send HTML email newsletters, grow your subscribers and manage your email list. Sign up today!

Essentially, I just have to do this:

# controllers/application.rb

before\_filter :set\_time\_zone

def set\_time\_zone  
Time.zone = @current\_user.time\_zone if @current\_user  
end

That will set the timezone to the particular user’s stored timezone and  
all will be well in the world.

The part I am trying to figure out is how to “guess” the user’s timezone  
in the first place. The application I am working on calls for the user  
registration to be dead simple and not include a huge timezone selection  
box.

I can think of two methods for guessing timezone:

1. Based on IP Address of client
2. Based on a cookie stored on their computer with their current offset

I would probably go with #2 (i.e store a cookie with their current  
offset from utc and then use that to fetch the first timezone which  
matches the offset)

Yes this would be inaccurate in that the wrong timezone may be selected  
but I would always have a select box in their settings area that would  
allow them to correct it and it would “get the job done”.

Thoughts? Is there a better way?

---

<div class="post-metadata">

**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [September 12, 2008, 11:25am UTC](https://www.ruby-forum.com/t/rails-2-1-timezone-support/148330/2 "2008-09-12T11:25:39Z")

</div>

On 11 Sep 2008, at 19:13, Nathan E. wrote:

> 1. Based on a cookie stored on their computer with their current
> 
> Thoughts? Is there a better way?

You can determine the timezone using javascript (as an integer):

var visitortime = new Date();  
visitortime.getTimezoneOffset()/60;

You can then set this value either in a cookie or in a hidden form  
field, depending on whether you would like to reverify the timezone on  
every page or just when registering.

You’ll have to map this number to an appropriate timezone (make an  
educated guess). Do know that javascript will give you the opposite of  
what you will expect:

Brussels for example will give -2 as a result while it is GMT+2.

Best regards

Peter De Berdt