dm-load.rb

require 'dm-core'
require 'dm-core/core_ext/symbol'
require 'dm-validations'
require 'appengine-apis'
require 'appengine-apis/local_boot'
require 'dm-appengine'

DataMapper::Logger.new(STDOUT, :debug)
DataMapper.setup(:default, "app_engine://memory")

gistfile1.txt

>> Location.first
=> nil
>> Location.find_by_ip 
ArgumentError: wrong # of arguments(0 for 1)
	from (irb):32:in `find_by_ip'
	from (irb):32
>> Location.find_by_ip("255.255.0.1")
NoMethodError: undefined method `add_sort' for #<AppEngine::Datastore::Query:0x15a28df8>
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-appengine-0.0.1/lib/dm-appengine.rb:175:in `map'
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-appengine-0.0.1/lib/dm-appengine.rb:175:in `parse_order'
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-appengine-0.0.1/lib/dm-appengine.rb:153:in `initialize'
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-appengine-0.0.1/lib/dm-appengine.rb:97:in `read'
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-core-0.10.0/lib/dm-core/repository.rb:145:in `read'
	from /Users/ted/Code/jruby/lib/ruby/gems/1.8/gems/dm-core-0.10.0/lib/dm-core/model.rb:396:in `first'
	from (irb):21:in `find_by_ip'
	from (irb):33
>> 

location.rb

class Location

  include DataMapper::Resource
  
  property :ip_start, Integer, :key => true
  property :country_code, String, :length => 2
  property :region_code, String, :length => 2
  property :city, String, :length => 64
  property :zipcode, String, :length => 6
  property :latitude, Float
  property :longitude, Float

  attr_accessor :ip

  def self.find_by_ip(ip)
    return unless valid_ip?(ip)
    o = ip.split('.').collect {|i| i.to_i }
    i = (o[0] * 256 + o[1]) * 256 + o[2]
    r = first(:ip_start.lte => ip, :order => [:ip_start.desc])
    r.ip = ip if r
    r
  end

  def self.valid_ip?(ip)
    ip =~ /^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})?$/
  end

end