Introduce grouped_collection_select helper.

[#1249 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

3 files changed, 103 insertions, 0 deletions

diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index 75de1fe2a6..30f3f31563 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,7 @@
 *Edge*
 
+* Introduce grouped_collection_select helper.  #1249 [Dan Codeape, Erik Ostrom]
+
 * Make sure javascript_include_tag/stylesheet_link_tag does not append ".js" or ".css" onto external urls. #1664 [Matthew Rudy Jacobs]
 
 * Ruby 1.9: fix Content-Length for multibyte send_data streaming.  #2661 [Sava Chankov]
diff --git a/actionpack/lib/action_view/helpers/form_options_helper.rb b/actionpack/lib/action_view/helpers/form_options_helper.rb
index 8cb5882aab..4620a52272 100644
--- a/actionpack/lib/action_view/helpers/form_options_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_options_helper.rb
@@ -162,6 +162,60 @@ module ActionView
         InstanceTag.new(object, method, self, options.delete(:object)).to_collection_select_tag(collection, value_method, text_method, options, html_options)
       end
 
+
+      # Returns <tt><select></tt>, <tt><optgroup></tt> and <tt><option></tt> tags for the collection of existing return values of
+      # +method+ for +object+'s class. The value returned from calling +method+ on the instance +object+ will
+      # be selected. If calling +method+ returns +nil+, no selection is made without including <tt>:prompt</tt>
+      # or <tt>:include_blank</tt> in the +options+ hash.
+      #
+      # Parameters:
+      # * +object+ - The instance of the class to be used for the select tag
+      # * +method+ - The attribute of +object+ corresponding to the select tag
+      # * +collection+ - An array of objects representing the <tt><optgroup></tt> tags.
+      # * +group_method+ - The name of a method which, when called on a member of +collection+, returns an
+      #   array of child objects representing the <tt><option></tt> tags.
+      # * +group_label_method+ - The name of a method which, when called on a member of +collection+, returns a
+      #   string to be used as the +label+ attribute for its <tt><optgroup></tt> tag.
+      # * +option_key_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the +value+ attribute for its <tt><option></tt> tag.
+      # * +option_value_method+ - The name of a method which, when called on a child object of a member of
+      #   +collection+, returns a value to be used as the contents of its <tt><option></tt> tag.
+      #
+      # Example object structure for use with this method:
+      #   class Continent < ActiveRecord::Base
+      #     has_many :countries
+      #     # attribs: id, name
+      #   end
+      #   class Country < ActiveRecord::Base
+      #     belongs_to :continent
+      #     # attribs: id, name, continent_id
+      #   end
+      #   class City < ActiveRecord::Base
+      #     belongs_to :country
+      #     # attribs: id, name, country_id
+      #   end
+      #
+      # Sample usage:
+      #   grouped_collection_select(:city, :country_id, @continents, :countries, :name, :id, :name)
+      #
+      # Possible output:
+      #   <select name="city[country_id]">
+      #     <optgroup label="Africa">
+      #       <option value="1">South Africa</option>
+      #       <option value="3">Somalia</option>
+      #     </optgroup>
+      #     <optgroup label="Europe">
+      #       <option value="7" selected="selected">Denmark</option>
+      #       <option value="2">Ireland</option>
+      #     </optgroup>
+      #   </select>
+      #
+      def grouped_collection_select(object, method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
+        InstanceTag.new(object, method, self, options.delete(:object)).to_grouped_collection_select_tag(collection, group_method, group_label_method, option_key_method, option_value_method, options, html_options)
+      end
+
+
+
       # Return select and option tags for the given object and method, using
       # #time_zone_options_for_select to generate the list of option tags.
       #
@@ -490,6 +544,15 @@ module ActionView
         )
       end
 
+      def to_grouped_collection_select_tag(collection, group_method, group_label_method, option_key_method, option_value_method, options, html_options)
+        html_options = html_options.stringify_keys
+        add_default_name_and_id(html_options)
+        value = value(object)
+        content_tag(
+          "select", add_options(option_groups_from_collection_for_select(collection, group_method, group_label_method, option_key_method, option_value_method, value), options, value), html_options
+        )
+      end
+
       def to_time_zone_select_tag(priority_zones, options, html_options)
         html_options = html_options.stringify_keys
         add_default_name_and_id(html_options)
@@ -524,6 +587,10 @@ module ActionView
         @template.collection_select(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_options.merge(html_options))
       end
 
+      def grouped_collection_select(method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
+        @template.grouped_collection_select(@object_name, method, collection, group_method, group_label_method, option_key_method, option_value_method, objectify_options(options), @default_options.merge(html_options))
+      end
+
       def time_zone_select(method, priority_zones = nil, options = {}, html_options = {})
         @template.time_zone_select(@object_name, method, priority_zones, objectify_options(options), @default_options.merge(html_options))
       end
diff --git a/actionpack/test/template/form_options_helper_test.rb b/actionpack/test/template/form_options_helper_test.rb
index 73624406be..aa40e46aa8 100644
--- a/actionpack/test/template/form_options_helper_test.rb
+++ b/actionpack/test/template/form_options_helper_test.rb
@@ -763,6 +763,40 @@ class FormOptionsHelperTest < ActionView::TestCase
                    html
   end
 
+  def test_grouped_collection_select
+    @continents = [
+      Continent.new("<Africa>", [Country.new("<sa>", "<South Africa>"), Country.new("so", "Somalia")] ),
+      Continent.new("Europe", [Country.new("dk", "Denmark"), Country.new("ie", "Ireland")] )
+    ]
+
+    @post = Post.new
+    @post.origin = 'dk'
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk" selected="selected">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      grouped_collection_select("post", "origin", @continents, :countries, :continent_name, :country_id, :country_name)
+    )
+  end
+
+  def test_grouped_collection_select_under_fields_for
+    @continents = [
+      Continent.new("<Africa>", [Country.new("<sa>", "<South Africa>"), Country.new("so", "Somalia")] ),
+      Continent.new("Europe", [Country.new("dk", "Denmark"), Country.new("ie", "Ireland")] )
+    ]
+
+    @post = Post.new
+    @post.origin = 'dk'
+
+    fields_for :post, @post do |f|
+      concat f.grouped_collection_select("origin", @continents, :countries, :continent_name, :country_id, :country_name)
+    end
+
+    assert_dom_equal(
+      %Q{<select id="post_origin" name="post[origin]"><optgroup label="&lt;Africa&gt;"><option value="&lt;sa&gt;">&lt;South Africa&gt;</option>\n<option value="so">Somalia</option></optgroup><optgroup label="Europe"><option value="dk" selected="selected">Denmark</option>\n<option value="ie">Ireland</option></optgroup></select>},
+      output_buffer
+    )
+  end
+
   private
 
     def dummy_posts