Added before/after create, update, save and destroy callbacks.

lib/mongo_mapper/document.rb

@@ -3,6 +3,13 @@ module Document
     def self.included(model)
       model.extend ClassMethods
       model.class_eval do
+        include ActiveSupport::Callbacks
+
+        define_callbacks  :before_create, :after_create, 
+                          :before_update, :after_update,
+                          :before_save, :after_save,
+                          :before_destroy, :after_destroy
+
         key :_id, String
         key :created_at, Time
         key :updated_at, Time
@@ -177,8 +184,14 @@ def new_record?
       read_attribute('_id').blank? || self.class.find_by_id(id).blank?
     end
 
+    def valid?
+      true
+    end
+
     def save
+      run_callbacks(:before_save)
       new_record? ? create : update
+      run_callbacks(:after_save)
       self
     end
 
@@ -188,7 +201,9 @@ def update_attributes(attrs={})
     end
 
     def destroy
+      run_callbacks(:before_destroy)
       collection.remove(:_id => id) unless new_record?
+      run_callbacks(:after_destroy)
       freeze
     end
 
@@ -254,12 +269,16 @@ def inspect
       def create
         write_attribute('_id', generate_id) if read_attribute('_id').blank?
         update_document_timestamps
+        run_callbacks(:before_create)
         collection.insert(attributes)
+        run_callbacks(:after_create)
       end
 
       def update
         update_document_timestamps
+        run_callbacks(:before_update)
         collection.modify({:_id => id}, attributes)
+        run_callbacks(:after_update)
       end
 
       def update_document_timestamps

test/test_callbacks.rb

@@ -0,0 +1,60 @@
+require 'test_helper'
+
+include ActiveSupport::Callbacks
+
+class CallbacksTest < Test::Unit::TestCase
+  context "Defining and running callbacks" do
+    setup do
+      @document = Class.new
+      @document.class_eval do
+        include MongoMapper::Document
+
+        key :name, String
+
+        %w(before_create after_create before_update after_update 
+           before_save after_save before_destroy after_destroy).each do |callback|
+          callback_method = "#{callback}_callback"
+          send(callback, callback_method)
+          define_method(callback_method) do
+            history << callback.to_sym
+          end
+        end
+
+        def history
+          @history ||= []
+        end
+      end
+      @document.collection.clear
+    end
+
+    should "work for before and after create" do
+      doc = @document.create(:name => 'John Nunemaker')
+      doc.history.should include(:before_create)
+      doc.history.should include(:after_create)
+    end
+
+    should "work for before and after update" do
+      doc = @document.create(:name => 'John Nunemaker')
+      doc.name = 'John Doe'
+      doc.save
+      doc.history.should include(:before_update)
+      doc.history.should include(:after_update)
+    end
+
+    should "work for before and after save" do
+      doc = @document.new
+      doc.name = 'John Doe'
+      doc.save
+      doc.history.should include(:before_save)
+      doc.history.should include(:after_save)
+    end
+
+    should "work for before and after destroy" do
+      doc = @document.create(:name => 'John Nunemaker')
+      doc.destroy
+      doc.history.should include(:before_destroy)
+      doc.history.should include(:after_destroy)
+    end
+  end
+
+end

test/test_document.rb

@@ -4,7 +4,7 @@ class DocumentTest < Test::Unit::TestCase
   context "The Document Class" do
     setup do
       @document = Class.new
-      @document.instance_eval { include MongoMapper::Document }
+      @document.class_eval { include MongoMapper::Document }
     end
 
     should "should be able to define a key" do
@@ -43,7 +43,7 @@ class DocumentTest < Test::Unit::TestCase
       @document.database.name.should == AlternateDatabase
 
       another_document = Class.new
-      another_document.instance_eval { include MongoMapper::Document }
+      another_document.class_eval { include MongoMapper::Document }
       another_document.database.should == MongoMapper.database
     end
 
@@ -62,7 +62,7 @@ class DocumentTest < Test::Unit::TestCase
   context "Database operations" do
     setup do
       @document = Class.new
-      @document.instance_eval do
+      @document.class_eval do
         include MongoMapper::Document
         collection 'users'
 
@@ -379,7 +379,7 @@ class DocumentTest < Test::Unit::TestCase
   context "An instance of a document" do
     setup do
       @document = Class.new
-      @document.instance_eval do
+      @document.class_eval do
         include MongoMapper::Document
 
         key :name, String
@@ -579,7 +579,7 @@ def name_and_age=(new_value)
 
       should "not be equal if id same but class different" do
         @another_document = Class.new
-        @another_document.instance_eval { include MongoMapper::Document }
+        @another_document.class_eval { include MongoMapper::Document }
 
         (@document.new('_id' => 1) == @another_document.new('_id' => 1)).should be(false)
       end