Added updated_by and stamped_by for both.

Refactored to DRY things up.
Backwards compatible with created_by.

README.rdoc

@@ -1,28 +1,64 @@
-= CreatedBy
+= UserStamps
 
-Adds a simple +belongs_to+ association to a +creator+ model based on a magic column
-+created_by+ as it's foreign key.
+Adds a simple +belongs_to+ associations to a user model based on a magic columns
++created_by+ and +updated_by+ as it's foreign key.
 
 == Example
 
   class User < ActiveRecord::Base
   end
 
+  class Item < ActiveRecord::Base
+    stamped_by :user
+  end
+
+  i = Item.find(1)
+  i.created_by  #=> 3
+  i.creator     #=> #<User id:3>
+  i.updated_by  #=> 5
+  i.updator     #=> #<User id:5>
+
+== Configuration
+
+You can specify configure how your +creator+ and +updator+ can be specified but
+you have to pass options to +created_by+ and +updated_by+ separately:
+
   class Item < ActiveRecord::Base
     created_by :user
+    updated_by :admin
   end
 
   i = Item.find(1)
   i.created_by  #=> 3
   i.creator     #=> #<User id:3>
+  i.updated_by  #=> 1
+  i.updator     #=> #<Admin id:1>
 
 == Options
 
 By default, the creator is required, you can turn this off with a :required option:
 
   created_by :user, :required => false
 
-You could pass a :foriegn_key option to set a specific +created_by+ foriegn key but
-you might as well just setup the association yourself at that point.
+By default, the updator is _not_ required because on create you will need to specify
+an updator, but you can turn this on with a :required option:
+
+  updated_by :admin, :required => true
+
+You could pass a :foriegn_key option to set a specific +created_by+ or +updated_by+
+foriegn key but you might as well just setup the association yourself at that point.
+
+== Using only Created By
+
+If you only care about creators you can just specify a +created_by+ instead of
++stamped_by+ as an option.
+
+  class Item < ActiveRecord::Base
+    created_by :user
+  end
+
+  i = Item.find(1)
+  i.created_by  #=> 3
+  i.creator     #=> #<User id:3>
 
-Copyright (c) 2009 Reid MacDonald <reid@laruby.com>, released under the MIT license
+Copyright (c) 2010 Reid MacDonald <reid@laruby.com>, released under the MIT license

lib/active_record/associations/user_stamps.rb

@@ -0,0 +1,50 @@
+module ActiveRecord   # :nodoc:
+  module Associations # :nodoc:
+    module UserStamps  # :nodoc:
+      ##
+      # Extends ActiveRecord::Base with ClassMethods
+      def self.included base
+        base.extend(ClassMethods)
+      end
+
+      ##
+      # Methods added to ActiveRecord::Base
+      module ClassMethods
+        ##
+        # Creates associations for +created_by+ and +updated_by+ using the respective configuration of each.
+        def stamped_by user_model
+          created_by user_model
+          updated_by user_model
+        end
+
+        ##
+        # Creates an association on the +created_by+ column to the supplied +user_model+ argument.
+        # You can override the +created_by+ column name with :foriegn_key but at that point you might
+        # as well set up the relationship yourself.
+        #
+        # Required by default.
+        def created_by user_model, options = {}
+          user_association :creator, user_model, options.reverse_merge(:foreign_key => 'created_by', :required => true)
+        end
+
+        ##
+        # Creates an association on the +updated_by+ column to the supplied +user_model+ argument.
+        # You can override the +updated_by+ column name with :foriegn_key but at that point you might
+        # as well set up the relationship yourself.
+        #
+        # Not required by default.
+        def updated_by user_model, options = {}
+          user_association :updator, user_model, options.reverse_merge(:foreign_key => 'updated_by', :required => false)
+        end
+
+        private
+          def user_association association, user_model, options
+            configuration = {:class_name => user_model.to_s.classify}.merge!(options)
+
+            belongs_to association, :foreign_key => configuration[:foreign_key], :class_name => configuration[:class_name]
+            validates_presence_of association if configuration[:required]
+          end
+      end
+    end
+  end
+end

spec/user_stamps_spec.rb

@@ -0,0 +1,101 @@
+require File.dirname(__FILE__) + '/spec_helper'
+
+class MockActiveRecord < ActiveRecord::Base
+  def self.column_names
+    %w[id created_by updated_by]
+  end
+
+  def self.columns
+    column_names.map do |name|
+      ActiveRecord::ConnectionAdapters::Column.new(name.to_s, nil)
+    end
+  end
+end
+
+describe ActiveRecord::Base do
+  it "includes ActiveRecord::Assocations::UserStamps::ClassMethods" do
+    ActiveRecord::Base.methods.should be_member('stamped_by')
+    ActiveRecord::Base.methods.should be_member('created_by')
+    ActiveRecord::Base.methods.should be_member('updated_by')
+  end
+end
+
+describe :created_by do
+  describe :belongs_to do
+    it "creates the belongs_to :creator association with default options" do
+      MockActiveRecord.should_receive(:belongs_to).with(:creator, :class_name => 'MockCreator', :foreign_key => 'created_by')
+      MockActiveRecord.created_by :mock_creator
+    end
+
+    it "creates the belongs_to association with alternate foreign_key" do
+      MockActiveRecord.should_receive(:belongs_to).with(:creator, :class_name => 'MockCreator', :foreign_key => 'creator_id')
+      MockActiveRecord.created_by :mock_creator, :foreign_key => 'creator_id'
+    end
+
+    it "creates the belongs_to association with alternate class_name (but why?)" do
+      MockActiveRecord.should_receive(:belongs_to).with(:creator, :class_name => 'AnotherClassName', :foreign_key => 'created_by')
+      MockActiveRecord.created_by :mock_creator, :class_name => 'AnotherClassName'
+    end
+
+    it 'ignores all other options' do
+      MockActiveRecord.should_receive(:belongs_to).with(:creator, :class_name => 'MockCreator', :foreign_key => 'created_by')
+      MockActiveRecord.created_by :mock_creator, :foo => 'Bar'
+    end
+  end
+
+  describe :validates_presence_of do
+    it 'is added by default' do
+      MockActiveRecord.should_receive(:validates_presence_of).with(:creator)
+      MockActiveRecord.created_by :mock_creator
+    end
+
+    it 'turns off validation for creator' do
+      MockActiveRecord.should_not_receive(:validates_presence_of)
+      MockActiveRecord.created_by :mock_creator, :required => false
+    end
+  end
+end
+
+describe :updated_by do
+  describe :belongs_to do
+    it "creates the belongs_to :updator association with default options" do
+      MockActiveRecord.should_receive(:belongs_to).with(:updator, :class_name => 'MockUpdator', :foreign_key => 'updated_by')
+      MockActiveRecord.updated_by :mock_updator
+    end
+
+    it "creates the belongs_to association with alternate foreign_key" do
+      MockActiveRecord.should_receive(:belongs_to).with(:updator, :class_name => 'MockUpdator', :foreign_key => 'updator_id')
+      MockActiveRecord.updated_by :mock_updator, :foreign_key => 'updator_id'
+    end
+
+    it "creates the belongs_to association with alternate class_name (but why?)" do
+      MockActiveRecord.should_receive(:belongs_to).with(:updator, :class_name => 'AnotherClassName', :foreign_key => 'updated_by')
+      MockActiveRecord.updated_by :mock_updator, :class_name => 'AnotherClassName'
+    end
+
+    it 'ignores all other options' do
+      MockActiveRecord.should_receive(:belongs_to).with(:updator, :class_name => 'MockUpdator', :foreign_key => 'updated_by')
+      MockActiveRecord.updated_by :mock_updator, :foo => 'Bar'
+    end
+  end
+
+  describe :validates_presence_of do
+    it 'is not added by default' do
+      MockActiveRecord.should_not_receive(:validates_presence_of).with(:updator)
+      MockActiveRecord.updated_by :mock_updator
+    end
+
+    it 'turns on validation for updator' do
+      MockActiveRecord.should_receive(:validates_presence_of)
+      MockActiveRecord.updated_by :mock_updator, :required => true
+    end
+  end
+end
+
+describe :stamped_by do
+  it 'uses the same model on created_by and updated_by' do
+    MockActiveRecord.should_receive(:created_by).with(:user)
+    MockActiveRecord.should_receive(:updated_by).with(:user)
+    MockActiveRecord.stamped_by :user
+  end
+end