Added the first part of Simply Helpful to core. The rest is pending a clean integartion of polymorphic urls [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6633 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 91 insertions, 0 deletions

diff --git a/actionpack/lib/action_controller/record_identifier.rb b/actionpack/lib/action_controller/record_identifier.rb
new file mode 100644
index 0000000000..1247665a8b
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+++ b/actionpack/lib/action_controller/record_identifier.rb
@@ -0,0 +1,91 @@
+module ActionController  
+  # The record identifier encapsulates a number of naming conventions for dealing with records, like Active Records or 
+  # Active Resources or pretty much any other model type that has an id. These patterns are then used to try elevate
+  # the view actions to a higher logical level. Example:
+  #
+  #   # routes
+  #   map.resources :posts
+  #
+  #   # view
+  #   <% div_for(post) do %>     <div id="post_45" class="post">
+  #     <%= post.body %>           What a wonderful world!
+  #   <% end %>                  </div>
+  #
+  #   # controller
+  #   def destroy
+  #     post = Post.find(params[:id])
+  #     post.destroy
+  #
+  #     respond_to do |format|
+  #       format.html { redirect_to(post) } # Calls polymorphic_url(post) which in turn calls post_url(post)
+  #       format.js do
+  #         # Calls: new Effect.fade('post_45');
+  #         render(:update) { |page| page[post].visual_effect(:fade) }
+  #       end
+  #     end
+  #   end
+  #
+  # As the example above shows, you can stop caring to a large extend what the actual id of the post is. You just know
+  # that one is being assigned and that the subsequent calls in redirect_to and the RJS expect that same naming 
+  # convention and allows you to write less code if you follow it.
+  module RecordIdentifier
+    extend self
+
+    # Returns plural/singular for a record or class. Example:
+    #
+    #   partial_path(post)   # => "posts/post"
+    #   partial_path(Person) # => "people/person"
+    def partial_path(record_or_class)
+      klass = class_from_record_or_class(record_or_class)
+      "#{klass.name.tableize}/#{klass.name.demodulize.underscore}"
+    end
+
+    # The DOM class convention is to use the singular form of an object or class. Examples:
+    #
+    #   dom_class(post)   # => "post"
+    #   dom_class(Person) # => "person"
+    #
+    # If you need to address multiple instances of the same class in the same view, you can prefix the dom_class:
+    #
+    #   dom_class(post, :edit)   # => "edit_post"
+    #   dom_class(Person, :edit) # => "edit_person"
+    def dom_class(record_or_class, prefix = nil)
+      [ prefix, singular_class_name(record_or_class) ].compact * '_'
+    end
+
+    # The DOM class convention is to use the singular form of an object or class with the id following an underscore. 
+    # If no id is found, prefix with "new_" instead. Examples:
+    #
+    #   dom_class(Post.new(:id => 45)) # => "post_45"
+    #   dom_class(Post.new)            # => "new_post"
+    #
+    # If you need to address multiple instances of the same class in the same view, you can prefix the dom_id:
+    #
+    #   dom_class(Post.new(:id => 45), :edit) # => "edit_post_45"
+    def dom_id(record, prefix = nil) 
+      prefix ||= 'new' unless record.id 
+      [ prefix, singular_class_name(record), record.id ].compact * '_'
+    end
+
+    # Returns the plural class name of a record or class. Examples:
+    #
+    #   plural_class_name(post)             # => "posts"
+    #   plural_class_name(Highrise::Person) # => "highrise_people"
+    def plural_class_name(record_or_class)
+      singular_class_name(record_or_class).pluralize
+    end
+
+    # Returns the singular class name of a record or class. Examples:
+    #
+    #   singular_class_name(post)             # => "post"
+    #   singular_class_name(Highrise::Person) # => "highrise_person"
+    def singular_class_name(record_or_class)
+      class_from_record_or_class(record_or_class).name.underscore.tr('/', '_')
+    end
+
+    private
+      def class_from_record_or_class(record_or_class)
+        record_or_class.is_a?(Class) ? record_or_class : record_or_class.class
+      end
+  end
+end
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