update domain with no ns issue, warn when no more ns's, hxr acl response

app/controllers/application_controller.rb

@@ -5,16 +5,21 @@ class ApplicationController < ActionController::Base
   
   rescue_from CanCan::AccessDenied, ActiveScaffold::ActionNotAllowed do |exception|
     flash.now[:error] = exception.message
-    render :template => 'errors/access_denied', :layout => 'errors'
+    render_access_denied
   end
 
   rescue_from ActiveScaffold::ActionNotAllowed do |exception|
     flash.now[:error] = I18n.t("errors.action_not_allowed")
-    render :template => 'errors/access_denied', :layout => 'errors'
+    render_access_denied
   end
   
   protected
   
+  def render_access_denied
+    layout = request.xhr? ? false : 'errors'
+    render :template => 'errors/access_denied', :layout => layout
+  end
+  
   def ensure_nested_under_domain
     raise CanCan::AccessDenied, "not found" unless nested? and nested_parent_record.is_a?(Domain)
   end

app/controllers/ns_controller.rb

@@ -35,4 +35,11 @@ class NsController < ApplicationController
     nested_singular_association? # || params[:parent_sti]
   end
   
+  def do_destroy
+    super
+    if successful? && nested_parent_record.ns_records.count == 0
+      flash[:warning] = "All NS records deleted, no other nameservers are associated with this domain!"
+    end
+  end
+  
 end

app/models/domain.rb

@@ -30,7 +30,7 @@ class Domain < ActiveRecord::Base
   validates :type, :inclusion => { :in => @@types, :message => "Unknown domain type" }
   validates :soa_record, :presence => {:unless => :slave?}
   validates_associated :soa_record #, :allow_nil => true
-  validates :ns_records, :presence => true, :length => {
+  validates :ns_records, :on => :create, :presence => true, :length => {
     :minimum => 2, :maximum => 10,
     :message => "must have be at least 2, at most 10"}
   validates_associated :records