Merge pull request #2034 from Casecommons/to_path

Allow ActiveModel-compatible instances to define their own partial paths

3 files changed, 39 insertions, 5 deletions

diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
index 1405b1bfe3..dca1c1aa44 100644
--- a/activemodel/lib/active_model/conversion.rb
+++ b/activemodel/lib/active_model/conversion.rb
@@ -1,9 +1,12 @@
+require 'active_support/concern'
+require 'active_support/inflector'
+
 module ActiveModel
   # == Active Model Conversions
   #
-  # Handles default conversions: to_model, to_key and to_param.
+  # Handles default conversions: to_model, to_key, to_param, and to_path.
   #
-  # Let's take for example this non persisted object.
+  # Let's take for example this non-persisted object.
   #
   #   class ContactMessage
   #     include ActiveModel::Conversion
@@ -18,8 +21,11 @@ module ActiveModel
   #   cm.to_model == self # => true
   #   cm.to_key           # => nil
   #   cm.to_param         # => nil
+  #   cm.to_path          # => "contact_messages/contact_message"
   #
   module Conversion
+    extend ActiveSupport::Concern
+
     # If your object is already designed to implement all of the Active Model
     # you can use the default <tt>:to_model</tt> implementation, which simply
     # returns self.
@@ -45,5 +51,21 @@ module ActiveModel
     def to_param
       persisted? ? to_key.join('-') : nil
     end
+
+    # Returns a string identifying the path associated with the object.
+    # ActionPack uses this to find a suitable partial to represent the object.
+    def to_path
+      self.class.to_path
+    end
+
+    module ClassMethods
+      def to_path
+        @_to_path ||= begin
+          element = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(self))
+          collection = ActiveSupport::Inflector.tableize(self)
+          "#{collection}/#{element}".freeze
+        end
+      end
+    end
   end
 end
diff --git a/activemodel/lib/active_model/lint.rb b/activemodel/lib/active_model/lint.rb
index b71ef4b22e..08c2e5fcf3 100644
--- a/activemodel/lib/active_model/lint.rb
+++ b/activemodel/lib/active_model/lint.rb
@@ -43,6 +43,16 @@ module ActiveModel
         assert model.to_param.nil?, "to_param should return nil when `persisted?` returns false"
       end
 
+      # == Responds to <tt>to_path</tt>
+      #
+      # Returns a string giving a relative path.  This is used for looking up
+      # partials. For example, a BlogPost model might return "blog_posts/blog_post"
+      #
+      def test_to_path
+        assert model.respond_to?(:to_path), "The model should respond to to_path"
+        assert_kind_of String, model.to_path
+      end
+
       # == Responds to <tt>valid?</tt>
       #
       # Returns a boolean that specifies whether the object is in a valid or invalid
@@ -66,15 +76,14 @@ module ActiveModel
 
       # == Naming
       #
-      # Model.model_name must return a string with some convenience methods as
-      # :human and :partial_path. Check ActiveModel::Naming for more information.
+      # Model.model_name must return a string with some convenience methods:
+      # :human, :singular, and :plural. Check ActiveModel::Naming for more information.
       #
       def test_model_naming
         assert model.class.respond_to?(:model_name), "The model should respond to model_name"
         model_name = model.class.model_name
         assert_kind_of String, model_name
         assert_kind_of String, model_name.human
-        assert_kind_of String, model_name.partial_path
         assert_kind_of String, model_name.singular
         assert_kind_of String, model_name.plural
       end
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index 4c1a82f413..26fa3062eb 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -1,12 +1,15 @@
 require 'active_support/inflector'
 require 'active_support/core_ext/hash/except'
 require 'active_support/core_ext/module/introspection'
+require 'active_support/core_ext/module/deprecation'
 
 module ActiveModel
   class Name < String
     attr_reader :singular, :plural, :element, :collection, :partial_path, :route_key, :param_key, :i18n_key
     alias_method :cache_key, :collection
 
+    deprecate :partial_path => "ActiveModel::Name#partial_path is deprecated. Call #to_path on model instances directly instead."
+
     def initialize(klass, namespace = nil, name = nil)
       name ||= klass.name
       super(name)