This commit merges most of the work done by Piotr Sarnacki in his Ruby Summer of Code project.

His work brings several capabilities from app to engines, as routes, middleware stack, asset handling and much more. Please check Rails::Engine documentation for more refenrences.

Merge remote branch 'drogus/engines'

3 files changed, 150 insertions, 4 deletions

diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index d79635cfb3..dadb1882e4 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -2,18 +2,22 @@ require 'active_support/inflector'
 
 module ActiveModel
   class Name < String
-    attr_reader :singular, :plural, :element, :collection, :partial_path
+    attr_reader :singular, :plural, :element, :collection, :partial_path, :route_key, :param_key
     alias_method :cache_key, :collection
 
-    def initialize(klass)
+    def initialize(klass, namespace = nil)
       super(klass.name)
+      @unnamespaced = self.sub(/^#{namespace.name}::/, '') if namespace
+
       @klass = klass
-      @singular = ActiveSupport::Inflector.underscore(self).tr('/', '_').freeze
+      @singular = _singularize(self).freeze
       @plural = ActiveSupport::Inflector.pluralize(@singular).freeze
       @element = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(self)).freeze
       @human = ActiveSupport::Inflector.humanize(@element).freeze
       @collection = ActiveSupport::Inflector.tableize(self).freeze
       @partial_path = "#{@collection}/#{@element}".freeze
+      @param_key = (namespace ? _singularize(@unnamespaced) : @singular).freeze
+      @route_key = (namespace ? ActiveSupport::Inflector.pluralize(@param_key) : @plural).freeze
     end
 
     # Transform the model name into a more humane format, using I18n. By default,
@@ -36,6 +40,11 @@ module ActiveModel
       options.reverse_merge! :scope => [@klass.i18n_scope, :models], :count => 1, :default => defaults
       I18n.translate(defaults.shift, options)
     end
+
+    private
+      def _singularize(str)
+        ActiveSupport::Inflector.underscore(str).tr('/', '_')
+      end
   end
 
   # == Active Model Naming
@@ -58,7 +67,8 @@ module ActiveModel
     # Returns an ActiveModel::Name object for module. It can be
     # used to retrieve all kinds of naming-related information.
     def model_name
-      @_model_name ||= ActiveModel::Name.new(self)
+      namespace = self.parents.detect { |n| n.respond_to?(:_railtie) }
+      @_model_name ||= ActiveModel::Name.new(self, namespace)
     end
 
     # Returns the plural class name of a record or class. Examples:
@@ -85,6 +95,30 @@ module ActiveModel
       plural(record_or_class) == singular(record_or_class)
     end
 
+    # Returns string to use while generating route names. It differs for
+    # namespaced models regarding whether it's inside isolated engine.
+    #
+    # For isolated engine:
+    # ActiveModel::Naming.route_key(Blog::Post) #=> posts
+    #
+    # For shared engine:
+    # ActiveModel::Naming.route_key(Blog::Post) #=> blog_posts
+    def self.route_key(record_or_class)
+      model_name_from_record_or_class(record_or_class).route_key
+    end
+
+    # Returns string to use for params names. It differs for
+    # namespaced models regarding whether it's inside isolated engine.
+    #
+    # For isolated engine:
+    # ActiveModel::Naming.route_key(Blog::Post) #=> post
+    #
+    # For shared engine:
+    # ActiveModel::Naming.route_key(Blog::Post) #=> blog_post
+    def self.param_key(record_or_class)
+      model_name_from_record_or_class(record_or_class).param_key
+    end
+
     private
       def self.model_name_from_record_or_class(record_or_class)
         (record_or_class.is_a?(Class) ? record_or_class : record_or_class.class).model_name
diff --git a/activemodel/test/cases/naming_test.rb b/activemodel/test/cases/naming_test.rb
index 5a8bff378a..c6b663ef93 100644
--- a/activemodel/test/cases/naming_test.rb
+++ b/activemodel/test/cases/naming_test.rb
@@ -2,6 +2,7 @@ require 'cases/helper'
 require 'models/contact'
 require 'models/sheep'
 require 'models/track_back'
+require 'models/blog_post'
 
 class NamingTest < ActiveModel::TestCase
   def setup
@@ -29,6 +30,86 @@ class NamingTest < ActiveModel::TestCase
   end
 end
 
+class NamingWithNamespacedModelInIsolatedNamespaceTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Blog::Post, Blog)
+  end
+
+  def test_singular
+    assert_equal 'blog_post', @model_name.singular
+  end
+
+  def test_plural
+    assert_equal 'blog_posts', @model_name.plural
+  end
+
+  def test_element
+    assert_equal 'post', @model_name.element
+  end
+
+  def test_collection
+    assert_equal 'blog/posts', @model_name.collection
+  end
+
+  def test_partial_path
+    assert_equal 'blog/posts/post', @model_name.partial_path
+  end
+
+  def test_human
+    assert_equal 'Post', @model_name.human
+  end
+
+  def test_route_key
+    assert_equal 'posts', @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal 'post', @model_name.param_key
+  end
+
+  def test_recognizing_namespace
+    assert_equal 'Post', Blog::Post.model_name.instance_variable_get("@unnamespaced")
+  end
+end
+
+class NamingWithNamespacedModelInSharedNamespaceTest < ActiveModel::TestCase
+  def setup
+    @model_name = ActiveModel::Name.new(Blog::Post)
+  end
+
+  def test_singular
+    assert_equal 'blog_post', @model_name.singular
+  end
+
+  def test_plural
+    assert_equal 'blog_posts', @model_name.plural
+  end
+
+  def test_element
+    assert_equal 'post', @model_name.element
+  end
+
+  def test_collection
+    assert_equal 'blog/posts', @model_name.collection
+  end
+
+  def test_partial_path
+    assert_equal 'blog/posts/post', @model_name.partial_path
+  end
+
+  def test_human
+    assert_equal 'Post', @model_name.human
+  end
+
+  def test_route_key
+    assert_equal 'blog_posts', @model_name.route_key
+  end
+
+  def test_param_key
+    assert_equal 'blog_post', @model_name.param_key
+  end
+end
+
 class NamingHelpersTest < Test::Unit::TestCase
   def setup
     @klass  = Contact
@@ -36,6 +117,8 @@ class NamingHelpersTest < Test::Unit::TestCase
     @singular = 'contact'
     @plural = 'contacts'
     @uncountable = Sheep
+    @route_key = 'contacts'
+    @param_key = 'contact'
   end
 
   def test_singular
@@ -54,6 +137,22 @@ class NamingHelpersTest < Test::Unit::TestCase
     assert_equal @plural, plural(@klass)
   end
 
+  def test_route_key
+    assert_equal @route_key, route_key(@record)
+  end
+
+  def test_route_key_for_class
+    assert_equal @route_key, route_key(@klass)
+  end
+
+  def test_param_key
+    assert_equal @param_key, param_key(@record)
+  end
+
+  def test_param_key_for_class
+    assert_equal @param_key, param_key(@klass)
+  end
+
   def test_uncountable
     assert uncountable?(@uncountable), "Expected 'sheep' to be uncoutable"
     assert !uncountable?(@klass), "Expected 'contact' to be countable"
diff --git a/activemodel/test/models/blog_post.rb b/activemodel/test/models/blog_post.rb
new file mode 100644
index 0000000000..d289177259
--- /dev/null
+++ b/activemodel/test/models/blog_post.rb
@@ -0,0 +1,13 @@
+module Blog
+  def self._railtie
+    Object.new
+  end
+
+  def self.table_name_prefix
+    "blog_"
+  end
+
+  class Post
+    extend ActiveModel::Naming
+  end
+end