Rails models with generated hex as parameter instead of id

Hexable.rb

module Hexable
  def self.included(base)
    base.class_eval do
      before_create :generate_hex
      attr_accessible :hex
    end
  end

  def to_param
    self.hex
  end

  private

  def generate_hex
    self.hex = SecureRandom.hex
  end
end

Post.rb

class Post < ActiveRecord::Base
  include Hexable
end

Hi there, this was really helpful! Quick question, how would you prevent collisions if the hex must be unique? Would you use a validator and have it up to the client to try again if there is a collision, or attempt to try again?

I actually just found a great way of doing this on SO. Here's the code:

module Tokenable
  extend ActiveSupport::Concern

  included do
    before_create :generate_token
  end

  protected

  def generate_token
    self.token = loop do
      random_token = SecureRandom.urlsafe_base64(nil, false)
      break random_token unless self.class.exists?(token: random_token)
    end
  end
end

I'm sure you could use the hex in place of the base64, but your odds of running into a collision is greater and you have a lower limit of things you can store naturally.

Cheers!