From 878f10c57d1776804ff0bab8924141c7d506d260 Mon Sep 17 00:00:00 2001
From: Georg Ledermann <ledermann@gmx.de>
Date: Mon, 18 May 2009 16:53:38 +0200
Subject: [PATCH] Scoped settings for any ActiveRecord instance

---
 MIT-LICENSE                                   |  1 +
 README.rdoc                                   | 14 +++-
 .../settings_migration/templates/migration.rb |  4 ++
 init.rb                                       | 12 +++-
 lib/settings.rb                               | 23 ++++--
 test/settings_test.rb                         | 72 +++++++++++++++----
 test/test_helper.rb                           | 11 +++
 7 files changed, 115 insertions(+), 22 deletions(-)

diff --git a/MIT-LICENSE b/MIT-LICENSE
index 2e6b14df..14f1ebed 100644
--- a/MIT-LICENSE
+++ b/MIT-LICENSE
@@ -1,4 +1,5 @@
 Copyright (c) 2006 Alex Wayne
+Some additional features added 2009 by Georg Ledermann
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
diff --git a/README.rdoc b/README.rdoc
index fc61dad7..6c36b037 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -52,5 +52,17 @@ Now even if the database is completely empty, you app will have some intelligent
 
   Settings.some_setting   # returns 'footastic'
 
+Settings may be bound to any existing ActiveRecord object. Define this association like this:
 
-That's all there is to it!. Enjoy!
\ No newline at end of file
+  class User < ActiveRecord::Base
+    has_settings
+  end
+
+Then you can set/get a setting for a given user instance just by doing this:
+
+  user = User.find(123)
+  user.settings.foo = 'Foo of user with ID 123'
+  user.settings.foo   # returns 'Foo of user with ID 123'
+
+
+That's all there is to it! Enjoy!
diff --git a/generators/settings_migration/templates/migration.rb b/generators/settings_migration/templates/migration.rb
index 31d4b360..955ded85 100644
--- a/generators/settings_migration/templates/migration.rb
+++ b/generators/settings_migration/templates/migration.rb
@@ -3,8 +3,12 @@ def self.up
     create_table :settings, :force => true do |t|
       t.string :var, :null => false
       t.text   :value, :null => true
+      t.integer :object_id, :null => true
+      t.string :object_type, :limit => 30, :null => true
       t.timestamps
     end
+    
+    add_index :settings, [ :object_type, :object_id, :var ], :uniq => true
   end
 
   def self.down
diff --git a/init.rb b/init.rb
index b24bc403..cf043760 100644
--- a/init.rb
+++ b/init.rb
@@ -1 +1,11 @@
-require 'settings'
\ No newline at end of file
+require 'settings'
+
+ActiveRecord::Base.class_eval do
+  def self.has_settings
+    class_eval do
+      def settings
+        Settings.scoped_by_object_type_and_object_id(self.class.base_class.to_s, self.id)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/settings.rb b/lib/settings.rb
index 843740e3..ceaec100 100644
--- a/lib/settings.rb
+++ b/lib/settings.rb
@@ -50,8 +50,8 @@ def self.all
     result.with_indifferent_access
   end
   
-  #retrieve a setting value by [] notation
-  def self.[](var_name)
+  #retrieve a setting value
+  def self.get(var_name)
     if var = object(var_name)
       var.value
     elsif @@defaults[var_name.to_s]
@@ -60,19 +60,30 @@ def self.[](var_name)
       nil
     end
   end
-  
-  #set a setting value by [] notation
-  def self.[]=(var_name, value)
+
+  #set a setting value
+  def self.set(var_name, value)
     var_name = var_name.to_s
     
     record = object(var_name) || Settings.new(:var => var_name)
     record.value = value
     record.save
+    value
+  end
+  
+  #get a setting value by [] notation
+  def self.[](var_name)
+    self.get(var_name)
+  end
+  
+  #set a setting value by [] notation
+  def self.[]=(var_name, value)
+    self.set(var_name, value)
   end
   
   #retrieve the actual Setting record
   def self.object(var_name)
-    Settings.find_by_var(var_name.to_s)
+    self.scoped_by_object_type_and_object_id(nil, nil).find_by_var(var_name.to_s)
   end
   
   #get the value field, YAML decoded
diff --git a/test/settings_test.rb b/test/settings_test.rb
index 05fc2031..9e4f0217 100644
--- a/test/settings_test.rb
+++ b/test/settings_test.rb
@@ -26,7 +26,7 @@ def test_get
 		assert_setting 'foo', :test
 		assert_setting 'bar', :test2
 	end
-	
+
 	def test_update
 		assert_assign_setting '321', :test
 	end
@@ -48,25 +48,69 @@ def test_serialization_of_float
     assert_equal 0.02, Settings.float * 2
   end
   
+  def test_object_scope
+    user1 = User.create :name => 'First user'
+    user2 = User.create :name => 'Second user'
+    
+    
+    assert_assign_setting 1, :one, user1
+    assert_assign_setting 2, :two, user2
+		
+    assert_setting 1, :one, user1
+    assert_setting 2, :two, user2
+    
+    assert_nil Settings.one
+    assert_nil Settings.two
+    assert_nil user1.settings.two
+    assert_nil user2.settings.one
+  end
+  
   private
-    def assert_setting(value, key)
+    def assert_setting(value, key, scope_object=nil)
       key = key.to_sym
-      assert_equal value, eval("Settings.#{key}")
-      assert_equal value, Settings[key.to_sym]
-      assert_equal value, Settings[key.to_s]
+      
+      if scope_object
+        assert_equal value, scope_object.instance_eval("settings.#{key}")
+        
+        # Array indexing on scopes does not work. Why?
+        # assert_equal value, scope_object.settings[key.to_sym]
+        # assert_equal value, scope_object.settings[key.to_s]
+        #
+        # As a work-around, use a "get" method
+        assert_equal value, scope_object.settings.get(key.to_sym)
+        assert_equal value, scope_object.settings.get(key.to_s)
+      else
+        assert_equal value, eval("Settings.#{key}")
+        assert_equal value, Settings[key.to_sym]
+        assert_equal value, Settings[key.to_s]
+      end
     end
     
-    def assert_assign_setting(value, key)
+    def assert_assign_setting(value, key, scope_object=nil)
       key = key.to_sym
-      assert_equal value, eval("Settings.#{key} = value")
-      assert_setting value, key
-      eval("Settings.#{key} = nil")
       
-      assert_equal value, (Settings[key] = value)
-      assert_setting value, key
-      Settings[key] = nil
+      if scope_object
+        assert_equal value, scope_object.instance_eval("settings.#{key} = value")
+        assert_setting value, key, scope_object
+        scope_object.instance_eval("settings.#{key} = nil")
+      
+        assert_equal value, (scope_object.settings.set(key,value))
+        assert_setting value, key, scope_object
+        scope_object.settings.set(key, nil)
+      
+        assert_equal value, (scope_object.settings.set(key.to_s,value))
+        assert_setting value, key, scope_object
+      else
+        assert_equal value, eval("Settings.#{key} = value")
+        assert_setting value, key
+        eval("Settings.#{key} = nil")
+      
+        assert_equal value, (Settings[key] = value)
+        assert_setting value, key
+        Settings[key] = nil
       
-      assert_equal value, (Settings[key.to_s] = value)
-      assert_setting value, key
+        assert_equal value, (Settings[key.to_s] = value)
+        assert_setting value, key
+      end
     end
 end
\ No newline at end of file
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 21f13f80..759d6218 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -8,13 +8,24 @@
 
 ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :dbfile => ":memory:")
 
+class User < ActiveRecord::Base
+  has_settings
+end
+
 def setup_db
   ActiveRecord::Schema.define(:version => 1) do
     create_table :settings do |t|
       t.string :var, :null => false
       t.text   :value, :null => true
+      t.integer :object_id, :null => true
+      t.string :object_type, :limit => 30, :null => true
       t.timestamps
     end
+    add_index :settings, [ :object_type, :object_id, :var ], :uniq => true
+    
+    create_table :users do |t|
+      t.string :name
+    end
   end
 end