move custom fields into its own concern

app/models/user.rb

@@ -8,10 +8,12 @@ require_dependency 'post_destroyer'
 require_dependency 'user_name_suggester'
 require_dependency 'pretty_text'
 require_dependency 'url_helper'
+require_dependency 'concern/has_custom_fields'
 
 class User < ActiveRecord::Base
   include Roleable
   include UrlHelper
+  include Concern::HasCustomFields
 
   has_many :posts
   has_many :notifications, dependent: :destroy
@@ -31,7 +33,6 @@ class User < ActiveRecord::Base
   has_many :invites, dependent: :destroy
   has_many :topic_links, dependent: :destroy
   has_many :uploads
-  has_many :user_custom_fields, dependent: :destroy
 
   has_one :facebook_user_info, dependent: :destroy
   has_one :twitter_user_info, dependent: :destroy
@@ -69,7 +70,6 @@ class User < ActiveRecord::Base
 
   after_save :update_tracked_topics
   after_save :clear_global_notice_if_needed
-  after_save :save_custom_fields
 
   after_create :create_email_token
   after_create :create_user_stat
@@ -589,35 +589,8 @@ class User < ActiveRecord::Base
     nil
   end
 
-  def custom_fields
-    @custom_fields ||= begin
-      @custom_fields_orig = Hash[*user_custom_fields.pluck(:name,:value).flatten]
-      @custom_fields_orig.dup
-    end
-  end
-
   protected
 
-  def save_custom_fields
-    if @custom_fields && @custom_fields_orig != @custom_fields
-      dup = @custom_fields.dup
-
-      user_custom_fields.each do |f|
-        if dup[f.name] != f.value
-          f.destroy
-        else
-          dup.remove[f.name]
-        end
-      end
-
-      dup.each do |k,v|
-        user_custom_fields.create(name: k, value: v)
-      end
-
-      @custom_fields_orig = @custom_fields
-    end
-  end
-
   def cook
     if bio_raw.present?
       self.bio_cooked = PrettyText.cook(bio_raw, omit_nofollow: self.has_trust_level?(:leader)) if bio_raw_changed?

lib/concern/has_custom_fields.rb

@@ -0,0 +1,39 @@
+module Concern
+  module HasCustomFields
+    extend ActiveSupport::Concern
+
+    included do
+      has_many :_custom_fields, dependent: :destroy, :class_name => "#{name}CustomField"
+      after_save :save_custom_fields
+    end
+
+    def custom_fields
+      @custom_fields ||= begin
+        @custom_fields_orig = Hash[*_custom_fields.pluck(:name,:value).flatten]
+        @custom_fields_orig.dup
+      end
+    end
+
+    protected
+
+    def save_custom_fields
+      if @custom_fields && @custom_fields_orig != @custom_fields
+        dup = @custom_fields.dup
+
+        _custom_fields.each do |f|
+          if dup[f.name] != f.value
+            f.destroy
+          else
+            dup.remove[f.name]
+          end
+        end
+
+        dup.each do |k,v|
+          _custom_fields.create(name: k, value: v)
+        end
+
+        @custom_fields_orig = @custom_fields
+      end
+    end
+  end
+end

spec/components/concern/has_custom_fields_spec.rb

@@ -0,0 +1,79 @@
+require "spec_helper"
+require_dependency "concern/has_custom_fields"
+
+describe Concern::HasCustomFields do
+
+  context "custom_fields" do
+    before do
+
+      Topic.exec_sql("create temporary table test_items(id SERIAL primary key)")
+      Topic.exec_sql("create temporary table test_item_custom_fields(id SERIAL primary key, test_item_id int, name varchar(256) not null, value text)")
+
+      class TestItem < ActiveRecord::Base
+        include Concern::HasCustomFields
+      end
+
+      class TestItemCustomField < ActiveRecord::Base
+        belongs_to :test_item
+      end
+    end
+
+    after do
+      Topic.exec_sql("drop table test_items")
+      Topic.exec_sql("drop table test_item_custom_fields")
+
+      # import is making my life hard, we need to nuke this out of orbit
+      des = ActiveSupport::DescendantsTracker.class_variable_get :@@direct_descendants
+      des[ActiveRecord::Base].delete(TestItem)
+      des[ActiveRecord::Base].delete(TestItemCustomField)
+    end
+
+    it "simple modification of custom fields" do
+      test_item = TestItem.new
+
+      test_item.custom_fields["a"].should == nil
+
+      test_item.custom_fields["bob"] = "marley"
+      test_item.custom_fields["jack"] = "black"
+      test_item.save
+
+      test_item = TestItem.find(test_item.id)
+
+      test_item.custom_fields["bob"].should == "marley"
+      test_item.custom_fields["jack"].should == "black"
+
+      test_item.custom_fields.delete("bob")
+      test_item.custom_fields["jack"] = "jill"
+
+      test_item.save
+      test_item = TestItem.find(test_item.id)
+
+      test_item.custom_fields.should == {"jack" => "jill"}
+    end
+
+
+    it "simple modifications don't interfere" do
+      test_item = TestItem.new
+
+      test_item.custom_fields["a"].should == nil
+
+      test_item.custom_fields["bob"] = "marley"
+      test_item.custom_fields["jack"] = "black"
+      test_item.save
+
+      test_item2 = TestItem.new
+
+      test_item2.custom_fields["x"].should == nil
+
+      test_item2.custom_fields["sixto"] = "rodriguez"
+      test_item2.custom_fields["de"] = "la playa"
+      test_item2.save
+
+      test_item = TestItem.find(test_item.id)
+      test_item2 = TestItem.find(test_item2.id)
+
+      test_item.custom_fields.should == {"jack" => "black", "bob" => "marley"}
+      test_item2.custom_fields.should == {"sixto" => "rodriguez", "de" => "la playa"}
+    end
+  end
+end