Using timezone javascript to set Time.zone

I've got a javascript that provides me with the timezone for the
client. I want to use this to set Time.zone so that all my times
stored in the database are displayed in the timezone for the client.
So really simplistically

var timezone = jstz.determine_timezone().timezone
Time.zone = timezone.olson_tz

obviously this can't be done. I've taken a look on the web and can
only find 'solutions' over two years old and as ROR moves so fast I
thought someone may know of a better solution. So can anyone suggest a
simple solution?

Many thanks

Hi Ben,

Hi Ben,

I've got a javascript that provides me with the timezone for the
client. I want to use this to set Time.zone so that all my times
stored in the database are displayed in the timezone for the client.
So really simplistically

var timezone = jstz.determine_timezone().timezone
Time.zone = timezone.olson_tz

obviously this can't be done. I've taken a look on the web and can
only find 'solutions' over two years old and as ROR moves so fast I
thought someone may know of a better solution. So can anyone suggest a
simple solution?

It needs to be set on the server. You could do an AJAX call.

Or, you could do this all in JavaScript, and simply translate the dates in the browser. Store -- and display -- one time zone, like UTC. But then on the client, collect all your dates (wrap them in a span.date or something that you can get using JS) and use the client's notion of the time zone to adjust their display on screen.

$$('span.date').each(function(elm){
  var d = new Date();
  var offset = d.getTimeZoneOffset() * 3600 * 1000;
  var adjusted = new Date(elm.innerHTML);
  adjusted.setTime(adjusted.getTime() + offset);
  elm.update(adjusted.toLocaleDateString());
});

Walter

Thanks for the replies.

The solution I've come up with for now is to use the javascript that
determines the timezone to store the timezone in a cookie using the
onload event. I then read it back out of the cookie in Rails with a
before_filter on application_controller.rb.

I'm not convinced its the best solution as obviously not everyone
turns cookies on, hmmm...

detect_timezone.js :
jstz.set_timezone_in_cookie = function () {
    var tz_info = jstz.determine_timezone();
    document.cookie="timezone =" + tz_info.timezone.olson_tz;
}

application_controller.rb :
before_filter :set_timezone
def set_timezone
  Time.zone = request.cookies["timezone"]
end

Any thoughts? Many thanks.

You could do it with AJAX as well and store it in a session variable…

routes.rb

post “timezone/set”

timezone_controller.rb

def set
session[:timezone] = params[:timezone]
end

application_controller.rb

before_filter :set_timezone

def set_timezone

Time.zone = session[:timezone]
end

detect_timezone.js

$.post("/timezone/set", { timezone: jstz.determine_timezone().timezone.olson_tz } );

I'm very close but need a little help as my timezone controller set
function isn't being called. I can see the post call being made in the
console and I can see before a filter being run on the timezone
controller, but no set function.

#routes.rb
  scope 'planbadmin' do
    resources :timezone do
      member do
        post :set
      end
    end
  end

# timezone_controller.rb
class TimezoneController < ApplicationController
  def set
    ldb("setting timezone = '#{params[:timezone]}'") #debug output
    session[:timezone] = params[:timezone]
  end
end

# application_controller.rb
before_filter :set_timezone
  def set_timezone
    ldb("setting timezone #{session[:timezone]}") #debug output
    Time.zone = session[:timezone]
  end

# detect_timezone.js
jstz.set_timezone_in_session = function () {
    //prototype
    new Ajax.Request("/planbadmin/timezone/set", {parameters:
{ timezone:jstz.determine_timezone().timezone.olson_tz }} );
}
onload = jstz.set_timezone_in_session();

#console output
Started POST "/planbadmin/timezone/set" for 127.0.0.1 at 2011-07-14
09:38:13 +01
00
  Processing by TimezoneController#set as JS
  Parameters: {"timezone"=>"Europe/London"}
  ←[1m←[36mUser Load (117.0ms)←[0m ←[1mSELECT TOP (1) [users].* FROM
[users] WH
ERE ([users].[userid] = N'benp')←[0m
Redirected to http://localhost/planbadmin/planb
Completed 302 Found in 140ms

Started GET "/planbadmin/planb" for 127.0.0.1 at 2011-07-14 09:38:13
+0100
  Processing by PlanbController#index as HTML
===> C:/Projects/PLANB/interface/1.5.5/app/controllers/
application_controller.rb
:68:in `set_timezone': setting timezone = ''
Rendered planb/index.html.erb within layouts/application (5.0ms)
Completed 200 OK in 35ms (Views: 35.0ms | ActiveRecord: 0.0ms)

Many thanks

#routes.rb

scope ‘planbadmin’ do

resources :timezone do

  member do

    post  :set

  end

end

end

That’s your problem there. By putting the “set” method under member, it’s expecting it to be called for a timezone such as “/timezone/:id/set”

If you’re going to set it up as a resource in routes, you probably want to use “collection” instead of “member” so it can be accessed via “/timezone/set”

You can run “rake routes” from the command line and you can see what it is expecting.

Of course the other option is just to add this one line to your routes instead of the resources snippet above:

post “timezone/set”

Hmm, so I've updated the routes

#routes.rb
  scope 'planbadmin' do
  ... #removed the timezone resource
  end
  post "timezone/set"

and the rake routes output is now
       timezone_set POST /timezone/set(.:format)
{:controller=>"timezone", :action=>"set"}

the console output is still exactly the same and the timezone set
function still isn't being called. Have you any other pointers? Again
thanks for your help with this its very much appreciated.

OK finally cracked it. Problem was with filters being run first in
application_controller.rb. The timezone_controller.rb set function was
being ignored as result of them. So

#routes.rb
  scope 'planbadmin' do
    resources :timezone do
      collection do
        post :set
      end
    end
  end

#timezone_controller.rb
class TimezoneController < ApplicationController
  skip_before_filter :admin, :authorise

  def set
    session[:timezone] = params[:timezone]
    redirect_to(:controller => "planb")
  end
end

Just a quick one, if I don't have that redirect it barfs about a
missing template. Is there a neat way around it?

Thanks VERY much for all the help.

You can use “render :nothing => true” instead

Hello friends,

Hello friends,

I am trying to get timezone in browser produce below error.

jstz is not defined

jstz.set_timezone_in_session = function () {

My code:

jstz.set_timezone_in_session = function () {
$.post("/timezone/set", { timezone:
jstz.determine_timezone().timezone.olson_tz } );
}
onload = jstz.set_timezone_in_session();

I am using JQuery.

If any one known about this suggestion me.

  Thanks,

Dhamodharan.N

Hello friends,

I forgot to download https://bitbucket.org/pellepim/jstimezonedetect/downloads detect_timezone.js.

Hello Ben Perry,

I download js from https://bitbucket.org/pellepim/jstimezonedetect/get/tip.zip