whereisciao · February 10, 2011 15:34 · Feb 10, 2011 · Feb 10, 2011 · Jan 10, 2011
diff --git a/mongoid.rb b/mongoid.rb
@@ -4,3 +4,8 @@
 
 User.observers = :user_observer
 User.instantiate_observers
+
+# The preferred syntax, similar to AR's setup
+# Mongoid.configure do |config|
+#   config.observers = :user_observer
+# end
diff --git a/mongoid.rb b/mongoid.rb
@@ -0,0 +1,6 @@
+require "#{RAILS_ROOT}/lib/mongoid/lib/observing.rb"
+
+# Initializer for Observers
+
+User.observers = :user_observer
+User.instantiate_observers
diff --git a/mongoid/observing.rb → observing.rb b/mongoid/observing.rb → observing.rb
diff --git a/user.rb b/user.rb
@@ -0,0 +1,10 @@
+require 'carrierwave/orm/mongoid'  
+
+class User
+  include Mongoid::Document
+  include Mongoid::Timestamps
+  include Mongoid::Observing
+
+  field :name
+  field :username
+end
diff --git a/user_observer.rb b/user_observer.rb
@@ -0,0 +1,5 @@
+class UserObserver < ActiveModel::Observer  
+  def after_validation(user)
+    puts "User Observer After Validation"
+  end
+end
diff --git a/mongoid/observing.rb b/mongoid/observing.rb
@@ -0,0 +1,26 @@
+module Mongoid
+  module Observing
+    CALLBACKS = [
+      :before_create, :before_destroy, :before_save, :before_update,
+      :before_validation, :after_create, :after_destroy, :after_save,
+      :after_update, :after_validation
+    ]
+
+    def self.included(base)
+      base.module_eval { include ActiveModel::Observing }
+
+      CALLBACKS.each do |callback|
+        callback_method = :"notify_observers_#{callback}"
+
+        base.module_eval <<-RUBY, __FILE__, __LINE__+1
+          #{callback}(#{callback_method.inspect})
+
+          def #{callback_method}(&block)
+            notify_observers(#{callback.inspect}, &block)
+          end
+          private #{callback_method.inspect}
+        RUBY
+      end
+    end
+  end
+end