gistfile1.rb

require "json"
require "httpclient"


# Usage:
#    reevoo_hq = LongLat.from_postcode("SE1 0RF")
#    reevoo_hq.long # => -0.10276
#    reevoo_hq.lat # => 51.500991
class LongLat
  PostcodeLookupError = Class.new(RuntimeError)
  attr_reader :long, :lat

  def initialize(long, lat)
    @long, @lat = long,lat
  end

  def self.from_postcode(postcode)
    response = HTTPClient.get("http://ernestmarples.com/?p=#{postcode.gsub(/[^a-zA-Z0-9]/, "")}&f=json")
    raise PostcodeLookupError, "Lookup failed" unless response.contenttype.include?("application/json")
    data = JSON.parse(response.content)
    raise PostcodeLookupError, "No such postcode" unless data["long"] and data["lat"] and data["long"].length > 0 and data["lat"].length > 0
    new data["long"].to_f, data["lat"].to_f
  end
end