Railscasts Search, Sort, Paginate, AJAX with Bootstrap 2

application_helper.rb

module ApplicationHelper

  def sortable(column, title = nil)
    title ||= column.titleize
    css_class = column == sort_column ? "current #{sort_direction}" : nil
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
    link_to (css_class ? title + direction_icon(direction) : title).html_safe, params.merge(:sort => column, :direction => direction, :page => nil), {:class => css_class}
  end

  private

  def direction_icon(direction)
    "<i class='#{direction == "desc" ? "icon-chevron-down" : "icon-chevron-up"}'></i>"
  end
end

filters.html.erb

<%= form_tag products_path, :method => 'get', :id => "product_search", :class=>"form-search" do %>
  <%= hidden_field_tag :direction, params[:direction] %> 
  <%= hidden_field_tag :sort, params[:sort] %>
  <%= text_field_tag :search, params[:search], :class=> "input-medium search-query" %>
  <%= submit_tag "Search", :name => nil, :class=> "btn" %>
<% end %>