A minimal re-usable module for "token" slugs on ActiveRecord models (AKA shortcodes, tiny urls)

token.rb

# token.rb
# A minimal re-usable module for "token" slugs on ActiveRecord models (AKA shortcodes, tiny urls)
#
# USAGE
#
#   class Project < ActiveRecord::Base
#     include Token
#   end
#
# see also:
#   http://stackoverflow.com/questions/6169541/rails-3-1rc1-to-param-from-param-without-effect
#   https://github.com/citrus/spree_mail/blob/master/lib/spree_mail/has_token.rb
#   https://github.com/bbommarito/token_generator/blob/master/lib/token_generator.rb
#   related gems: stringex, friendlyid

require 'securerandom'

module Token
  extend ActiveSupport::Concern
  
  included do
    validates :token, presence:true, uniqueness:true

    before_validation :set_token, on: :create
  end

  module ClassMethods
    # via http://tomafro.net/2009/09/tip-the-case-for-from-param
    def from_param(param)
      self.where( token: param ).first
    end
  end

  def to_param
    self.token
  end

private
  def generate_token
    # keep generating tokens until one is unique
    token = nil

    loop do
      token = SecureRandom.random_number(36**5).to_s(36)
      break if self.class.from_param(token).nil?
    end

    token
  end
  def set_token
    self.token ||= generate_token
  end

end

token_example.rb

require 'active_support'
require 'active_record'
require './token'

ActiveRecord::Base.establish_connection(
  :adapter => 'sqlite3',
  :database => 'test_token.sqlite3.db'
)

begin
  ActiveRecord::Schema.define do
    create_table :projects do |t|
      t.string :name
      t.string :token
    end
  end
rescue ActiveRecord::StatementInvalid
  # Do nothing - schema already exists
end

class Project < ActiveRecord::Base
  include Token
end

@project = Project.create!
@project.to_param == @project.token
Project.from_param(@project.to_param) == @project