Rails Helpers

ApplicationController helpers in views
(putting the methods in ApplicationHelper only makes them available to views,
if you need them in controllers AND views, define them in
ApplicationController
and use the helper_method method)
in ApplicationController:
helper_method :method_name1, :method_name2, :so_on_and_so_forth

View Helpers in Controllers or Models
(might make you feel dirty, but if you need to you'll get over it)
1. make a module in /lib:
"shared.rb"
--
module Shared
def shared_help
SharedHelper.instance
end

class SharedHelper
include Singleton
include ActionView::Helpers::TextHelper
include ActionView::Helpers::UrlHelper
include ActionView::Helpers::DateHelper
include ActionView::Helpers::TagHelper
include ActionView::Helpers::NumberHelper
# and whatever else you need ...
end
end

2. include the module in a Controller or Model:
include Shared

3. call your view helpers like 'shared_help.method', i.e.:
shared_help.mail_to(email_addr)

Another way to do it, using a class instead of a module:
1. # create a new file inside lib/ and call it helpers.rb
2. # paste the following:
3.
4. def help
5. Helper.instance
6. end
7.
8. class Helper
9. include Singleton
11. include ActionView::Helpers::DateHelper
12. include ActionView::Helpers::TextHelper
13. end
14.
15. # then in any model or controller:
16. require 'lib/helpers'
17.
18. # to use:
19. # help.name_of_helper
20. # EX: help.pluralize 10, "person"

View helpers in email templates
use the helper method in your mailer class, like:
class Notifier < ActionMailer::Base
helper :application
# ... your mailer methods
end