gistfile1.rb

class ApplicationController < ActionController::Base
  def set_time_zone
    if current_user
      Time.zone = current_user.time_zone 
      logger.debug "set time zone to #{Time.zone.name}"
    end
  end
end

class Reports::BaseController < ApplicationController
  protected
    def normalize_date_range
      logger.debug "normalizing date range"
      @start_period = normalized_start_period
      @end_period   = normalized_end_period
      @start_period, @end_period = @end_period, @start_period if @start_period > @end_period
      logger.debug "start: #{@start_period}"
    end

    def normalized_start_period
      params_or_default(:start_period).at_beginning_of_day
    end
  
    def normalized_end_period
      params_or_default(:end_period).end_of_day
    end
  
    def params_or_default(key)
      if params[key].blank?
         Time.zone.now - 1.day
       else
         Time.zone.parse(params[key])
       end
    end
end

# on local machine, having set time zone to EST
set time zone to Eastern Time (US & Canada)
normalizing date range
start: 2009-03-02 00:00:00 -0500

$ ruby -v
ruby 1.8.6 (2008-03-03 patchlevel 114) [universal-darwin9.0]
$ rails -v
Rails 2.2.2

# on server, setting it to +13
set time zone to Nuku'alofa
normalizing date range
start: Mon Mar 02 00:00:00 -0500 2009 # it's *always* this, no matter what the time we set for user

$ ruby -v
ruby 1.8.6 (2008-03-03 patchlevel 114) [x86_64-linux]
$ rails -v
Rails 2.2.2