Question

I have a model that has a latitude, longitude, and datetime attributes and I want to be able to calculate the timezone of that location and set it for each individual instance of the model. Here is the code that I have written to get the time zone is there something I am missing?

require 'nokogiri'
require 'open-uri'

before_validation :set_current_time_zone

def set_current_time_zone
  Time.zone = find_timezone_based_on_location
end

def find_time_zone_based_on_location
  url = "http://www.earthtools.org/timezone-1.1/#{self.latitude}/#{self.longitude}"
  doc = Nokogiri::XML(open(url))
  offset = doc.at_xpath('//offset').text().to_i
  if offset == -5
    "Eastern Time (US & Canada)"
  ....
  elsif offset == -8 
    "Pacific Time (US & Canada)"
  end
end

Is there something that I am missing as to why this is not setting the correct time?

Answer 1

I was able to get the code to work by changing the set_current_time_zone to the following:

def set_current_time_zone
  self.attributeActiveSupport::TimeZone[find_time_zone_based_on_location].local_to_utc(self.attribute)
end

This will find the correct Time zone and then translate that time into UTC.