geoip.rb

require 'ipaddr'
require 'net/http'
require 'uri'
require 'json'

module GeoIP
  def self.configuration
    @configuration ||= {}
  end

  def self.configuration=(hash)
    @configuration = hash
  end

  def self.ip_to_country_iso(ip_address)
    IPAddr.new(ip_address) # Validation
    uri = URI.parse("https://geoip.maxmind.com/geoip/v2.0/country/#{ip_address}")
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    http.verify_mode = OpenSSL::SSL::VERIFY_NONE
    request = Net::HTTP::Get.new(uri.request_uri)
    request.basic_auth(configuration[:user_id], configuration[:license_key])
    response = http.request(request)
    raise "HTTP Error #{response.code} talking to maxmind" unless response.code.to_i == 200
    struct = JSON.parse(response.body.to_s)
    struct["country"]["iso_code"] if struct["country"]
  end
end