ctm_url_with_mustache.rb

module Ctm
  module UrlWithMustache
    extend ActiveSupport::Concern

    included do
      before_validation :mustache_safe_url_prepare
      after_validation :mustache_safe_url_restore

      def mustache_safe_url_prepare
        @_mustache_safe_prepared_urls = {}
        self.class.mustache_safe_urls.each {|attr|
          method = attr.to_sym
          @_mustache_safe_prepared_urls[method] = self.send(method)
          self.send("#{attr}=", Mustache.render(self.send(method) || '', {}))
        }
      end

      def mustache_safe_url_restore
        self.class.mustache_safe_urls.each {|attr|
          self.send("#{attr}=", @_mustache_safe_prepared_urls[attr.to_sym])
        }
      end
    end

    class_methods do

      def mustache_validated_url(*attrs)
        @_mustache_safe_urls ||= Set.new
        attrs.each {|attr|
          @_mustache_safe_urls << attr
        }
      end

      def mustache_safe_urls
        @_mustache_safe_urls
      end

    end

  end
end