If you're looking for a ruby based solution for this problem, I recommend using the Google Calculator method a solution similar to the following: http://j.mp/QIC564
require 'faraday'
require 'faraday_middleware'
require 'json'
# Debug:
# require "pry"
country_code_src = "USD"
country_code_dst = "INR"
connection = Faraday.get("http://www.google.com/ig/calculator?hl=en&q=1#{country_code_src}=?#{country_code_dst}")
currency_comparison_hash = eval connection.body #Google's output is not JSON, it's a hash
dst_currency_value, *dst_currency_text = *currency_comparison_hash[:rhs].split(' ')
dst_currency_value = dst_currency_value.to_f
dst_currency_text = dst_currency_text.join(' ')
puts "#{country_code_dst} -> #{dst_currency_value} (#{dst_currency_text} to 1 #{country_code_src})"
