Store an IPv4 or IPv6 network number address in a varbinary(16) column using rails ActiveRecord. This is a decent example of using code to perform the v4/v6 conversion instead of the database. VARBINARY(16) allows one to store the numeric value of an IP address so that you can perform range queries and manage a consistent form with respect to al…

ipaddr.rb

require 'ipaddr'

class Ip < ActiveRecord::Base
  attr_accessible :ip, :addr, :other_columns
  
  # The 'addr' accessor is what you use to properly set/get the 'ip' column.
  # This sets an instance variable to store the IPAddr class representing the
  # ip column in either IPv4 or IPv6.
  attr_accessor :addr
  validates_presence_of :addr, :message => "Invalid or empty IP Address"
  
  after_find :init_addr
  
  # Store the string rep of a v4/6 address into the ip column
  def addr=(str)
    begin
      @addr = IPAddr.new(str)
    rescue => e
      errors.add(:addr, e.to_s)
    end
    # Set ip to a string of bytes in network-order so that ActiveRecord will
    # properly cast the data on insert into the varbinary.
    self.ip = @addr.hton if(!@addr.nil?)
  end
  
  # Returns the canonical string form of the ip address
  def addr
        @addr.to_s
  end
  
  # Returns the IPAddr class
  def ipaddr
  	@addr
  end
  
  # Return true if the current record (ip) is an IPv6 address
  def is_ipv6?
  	if (!self.ip.nil?)
  	  @addr.ipv6?
  	else
  	  false
  	end
  end

  private
  	# After reading a record, set @addr to the IPAddr of the ip column.
  	def init_addr
  	  # From the DB, ip is a string of bytes in network-order.
  	  @addr = IPAddr.new_ntoh(ip)
  	end

end

This was super helpful, thanks man!