application_helper.rb

application_helper.rb

module ApplicationHelper

  # Helper method to wrap an input field for twitter bootstrap
  # @param [Object] model_instance Instanciated model
  # @param [Symbol] field_name Attribute name of the field being referred to in this block
  # @param [Hash] options Set of options. See example.
  #
  # @example
  #     <!--
  #       Available options:
  #       :required [Boolean] show the 'required' asterisk (true | false)
  #       :help [String] default help text to show below the field
  #     -->
  # 
  #     <!-- @person is an instanciated Person -->
  #     <%= field_wrapper(@person, :first_name, {:required => true, :help => "first name of person"}) do %>
  #       <%= f.text_field :first_name, :size => 30, :type => "text", :class => "xlarge" %>
  #     <% end %>
  #     
  #     <!-- should return the following -->
  #     <div class="clearfix">
  #       <label for="person_first_name">
  #         <span class="required">*</span>
  #         First Name
  #       </label>
  #       <div class="input">
  #         <input type="text" name="person[first_name]" id="person_first_name" class="xlarge" size="30" />
  #         <span class="help-block">
  #           first name of person
  #         </span>
  #       </div>
  #     </div>
  #  

  def field_wrapper(model_instance, field_name, options={}, &block)
    content = capture(&block) # capture the contents of the block

    field_id = model_instance.class.name.underscore
    
    # Determine the classes for the outer div wrapper
    classes = ["clearfix"]
    classes << "error" if model_instance.errors[field_name].any?

    content_tag(:div, :class => classes.join(' ')) do
      content_tag(:label, :for => "#{field_id}_#{field_name}") do
        # Determine if the field is required
        if options[:required] == true
          content_tag(:span, "*", :class => "required")
        end
        field_name.to_s.humanize.titleize
      end +
      content_tag(:div, :class => "input") do
        content +
        if model_instance.errors[field_name].any?
          content_tag(:span, :class => "help-block") do
            model_instance.errors[field_name].join(', ')
          end
        else
          if options[:help].present?
            content_tag(:span, :class => "help-block") do
              options[:help]
            end
          end
        end
      end
    end

  end
end