Meant for a rails controller; provides actions to convert ipv4 addresses to integers and vice versa

ip_conversion_tools.rb

module IpConversionTools
  def self.included(base)
    base.class_eval do
      helper_method :ip_to_i
      helper_method :ip_to_s
    end
  end

  protected
  def ip_to_i(ip=nil)
    begin
      IPAddr.new(ip).to_i
    rescue
      0
    end
  end

  def ip_to_s(ip=nil)
    begin
      IPAddr.new(ip, Socket::AF_INET).to_s
    rescue
      '0.0.0.0'
    end
  end
end

ip_conversion_tools_spec.rb

require 'spec/spec_helper'

describe IpConversionTools do
  class IpConversionToolsTestController < ApplicationController
    include IpConversionTools
  end

  subject { IpConversionToolsTestController.new }

  context 'ip_to_i' do
    def do_invoke(ip=nil)
      subject.send(:ip_to_i, ip)
    end

    it 'should return a Fixnum' do
      do_invoke.class.should == Fixnum
    end

    it 'should return 0 if the ip received is nil' do
      do_invoke(nil).should == 0
    end

    it 'should return 0 if the ip received is a string but not an ip address' do
      do_invoke('bad_ip').should == 0
    end

    it 'should return an integer representation of the ip received' do
      do_invoke('127.0.0.1').should == 2130706433
    end
  end

  context 'ip_to_s' do
    def do_invoke(ip=nil)
      subject.send(:ip_to_s, ip)
    end

    it 'should return a string' do
      do_invoke.class.should == String
    end

    it 'should return empty ip if it receives a string argument' do
      do_invoke('').should == '0.0.0.0'
    end

    it 'should return a string representation of the ip received' do
      do_invoke(2130706433).should == '127.0.0.1'
    end
  end
end