Using view_context

gistfile1.rb

# app/controllers/posts_controller.rb
class PostsController < ActionController::Base
  def show
    # ...
    tags = view_context.generate_tags(@post)
    email_link = view_context.mail_to(@user.email)
    # ...
  end 
end

# app/helpers/posts_helper.rb
module PostsHelper
  def generate_tags(post)
    "Generate Tags"
  end
end