Template model class for having configurable messages stored in database.

template.rb

class Template < ActiveRecord::Base

  validates_uniqueness_of :name

  #  Set default values in this hash
  DEFAULT_VALUES = {:community => "Ruby on Rails"}

  #  Find template by its name
  #    @template = Template.where(:name => "welcome_message").first
  #  Template has the following message attribute
  #    @template.message 
  #    => "Hello {user_name}. Thank you for joining {community}."
  #  Call interpolate method and pass the hash
  #    @template.interpolate({:user_name => "User Name"})

  def interpolate(values)
    values = values.reverse_merge! DEFAULT_VALUES
    text = message
    attr_available.split(',').each do |attr|
      text = text.sub("{#{attr}}", values[attr.to_sym])
    end
    text
  end

end

# == Schema Information
#
# Table name: templates
#
#  id             :integer         not null, primary key
#  message        :text
#  attr_available :text
#  name           :string(255)
#  created_at     :datetime
#  updated_at     :datetime
#