module ActionView # There's also a convenience method for rendering sub templates within the current controller that depends on a single object # (we call this kind of sub templates for partials). It relies on the fact that partials should follow the naming convention of being # prefixed with an underscore -- as to separate them from regular templates that could be rendered on their own. # # In a template for Advertiser#account: # # <%= render_partial "account" %> # # This would render "advertiser/_account.rhtml" and pass the instance variable @account in as a local variable +account+ to # the template for display. # # In another template for Advertiser#buy, we could have: # # <%= render_partial "account", :account => @buyer %> # # <% for ad in @advertisements %> # <%= render_partial "ad", :ad => ad %> # <% end %> # # This would first render "advertiser/_account.rhtml" with @buyer passed in as the local variable +account+, then render # "advertiser/_ad.rhtml" and pass the local variable +ad+ to the template for display. # # == Rendering a collection of partials # # The example of partial use describes a familiar pattern where a template needs to iterate over an array and render a sub # template for each of the elements. This pattern has been implemented as a single method that accepts an array and renders # a partial by the same name as the elements contained within. So the three-lined example in "Using partials" can be rewritten # with a single line: # # <%= render_partial_collection "ad", @advertisements %> # # This will render "advertiser/_ad.rhtml" and pass the local variable +ad+ to the template for display. An iteration counter # will automatically be made available to the template with a name of the form +partial_name_counter+. In the case of the # example above, the template would be fed +ad_counter+. # # == Rendering shared partials # # Two controllers can share a set of partials and render them like this: # # <%= render_partial "advertisement/ad", :ad => @advertisement %> # # This will render the partial "advertisement/_ad.rhtml" regardless of which controller this is being called from. module Partials def render_partial(partial_path, local_assigns = {}, deprecated_local_assigns = {}) path, partial_name = partial_pieces(partial_path) object = extracting_object(partial_name, local_assigns, deprecated_local_assigns) local_assigns = extract_local_assigns(local_assigns, deprecated_local_assigns) add_counter_to_local_assigns!(partial_name, local_assigns) render("#{path}/_#{partial_name}", { partial_name => object }.merge(local_assigns)) end def render_partial_collection(partial_name, collection, partial_spacer_template = nil, local_assigns = {}) collection_of_partials = Array.new counter_name = partial_counter_name(partial_name) collection.each_with_index do |element, counter| collection_of_partials.push(render_partial(partial_name, element, { counter_name => counter }.merge(local_assigns))) end return nil if collection_of_partials.empty? if partial_spacer_template spacer_path, spacer_name = partial_pieces(partial_spacer_template) collection_of_partials.join(render("#{spacer_path}/_#{spacer_name}")) else collection_of_partials end end alias_method :render_collection_of_partials, :render_partial_collection private def partial_pieces(partial_path) if partial_path.include?('/') return File.dirname(partial_path), File.basename(partial_path) else return controller.class.controller_path, partial_path end end def partial_counter_name(partial_name) "#{partial_name.split('/').last}_counter" end def extracting_object(partial_name, local_assigns, deprecated_local_assigns) if local_assigns.is_a?(Hash) || local_assigns.nil? controller.instance_variable_get("@#{partial_name}") else # deprecated form where object could be passed in as second parameter local_assigns end end def extract_local_assigns(local_assigns, deprecated_local_assigns) local_assigns.is_a?(Hash) ? local_assigns : deprecated_local_assigns end def add_counter_to_local_assigns!(partial_name, local_assigns) counter_name = partial_counter_name(partial_name) local_assigns[counter_name] = 1 unless local_assigns.has_key?(counter_name) end end end