Added helper for accessing the top level document. And more rails compatibility.

lib/couchrest/more/casted_model.rb

@@ -27,6 +27,13 @@ module CouchRest
       super(key.to_s)
     end
     
+    # Gets a reference to the top level extended
+    # document that a model is saved inside of
+    def base_doc
+      raise "Cannot call base_doc on a model that is not yet casted by a document" unless @casted_by
+      @casted_by.base_doc
+    end
+    
     # False if the casted model has already
     # been saved in the containing document
     def new_model?

lib/couchrest/more/extended_document.rb

@@ -110,6 +110,19 @@ module CouchRest
       self.class.properties
     end
     
+    # Gets a reference to the actual document in the DB
+    # Calls up to the next document if there is one,
+    # Otherwise we're at the top and we return self
+    def base_doc
+      return self if base_doc?
+      @casted_by.base_doc
+    end
+    
+    # Checks if we're the top document
+    def base_doc?
+      !@casted_by
+    end
+    
     # Takes a hash as argument, and applies the values by using writer methods
     # for each key. It doesn't save the document at the end. Raises a NoMethodError if the corresponding methods are
     # missing. In case of error, no attributes are changed.    

lib/couchrest/support/rails.rb

@@ -21,8 +21,17 @@ CouchRest::Document.class_eval do
     super
   end
   alias_method :kind_of?, :is_a?
+  alias_method :to_param, :id
 end
 
+CouchRest::CastedModel.class_eval do
+  # The to_param method is needed for rails to generate resourceful routes.
+  # In your controller, remember that it's actually the id of the document.
+  def id
+    base_doc.id
+  end
+  alias_method :to_param, :id
+end
 
 require Pathname.new(File.dirname(__FILE__)).join('..', 'validation', 'validation_errors')
 

spec/couchrest/more/casted_model_spec.rb

@@ -5,6 +5,7 @@ require File.join(FIXTURE_PATH, 'more', 'card')
 require File.join(FIXTURE_PATH, 'more', 'cat')
 require File.join(FIXTURE_PATH, 'more', 'person')
 require File.join(FIXTURE_PATH, 'more', 'question')
+require File.join(FIXTURE_PATH, 'more', 'course')
 
 
 class WithCastedModelMixin < Hash
@@ -299,4 +300,53 @@ describe CouchRest::CastedModel do
       @cat.toys.first.new_model?.should be_true
     end
   end
+  
+  describe "calling base_doc from a nested casted model" do
+    before :each do
+      @course = Course.new(:title => 'Science 101')
+      @professor = Person.new(:name => 'Professor Plum')
+      @cat = Cat.new(:name => 'Scratchy')
+      @toy1 = CatToy.new
+      @toy2 = CatToy.new
+      @course.professor = @professor
+      @professor.pet = @cat
+      @cat.favorite_toy = @toy1
+      @cat.toys << @toy2
+    end
+    
+    it "should reference the top document for" do
+      @course.base_doc.should === @course
+      @professor.base_doc.should === @course
+      @cat.base_doc.should === @course
+      @toy1.base_doc.should === @course
+      @toy2.base_doc.should === @course
+    end
+    
+    it "should call setter on top document" do
+      @toy1.base_doc.title = 'Tom Foolery'
+      @course.title.should == 'Tom Foolery'
+    end
+  end
+  
+  describe "calling base_doc.save from a nested casted model" do
+    before :each do
+      reset_test_db!
+      @cat = Cat.new(:name => 'Snowball')
+      @toy = CatToy.new
+      @cat.favorite_toy = @toy
+    end
+    
+    it "should not save parent document when casted model is invalid" do
+      @toy.should_not be_valid
+      @toy.base_doc.save.should be_false
+      lambda{@toy.base_doc.save!}.should raise_error
+    end
+    
+    it "should save parent document when nested casted model is valid" do
+      @toy.name = "Mr Squeaks"
+      @toy.should be_valid
+      @toy.base_doc.save.should be_true
+      lambda{@toy.base_doc.save!}.should_not raise_error
+    end
+  end
 end

spec/fixtures/more/person.rb

@@ -1,6 +1,7 @@
 class Person < Hash
   include ::CouchRest::CastedModel
   property :name
+  property :pet, :cast_as => 'Cat'
   
   def last_name
     name.last