From 2161b8745a22379356b466a60b9aa763c0593f9b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mislav=20Marohni=C4=87?= Date: Fri, 16 Apr 2010 19:37:12 +0200 Subject: improve how ActiveRecord::Observer defines callbacks on observed models Instead of using a single `notify_observers` call for every callback type, each observer now registers a unique callback for itself. Example: before_save :_notify_user_observer_for_before_save def _notify_user_observer_for_before_save observer.update(:before_save, self) end Benefit: "before" callbacks halt when `observer.update` returns false. This way, ActiveRecord observers can prevent records from saving. [#4087 state:committed] Signed-off-by: Jeremy Kemper --- activerecord/CHANGELOG | 5 +++++ activerecord/lib/active_record/observer.rb | 26 +++++++++++++++++++------- 2 files changed, 24 insertions(+), 7 deletions(-) diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG index 8ecef6574f..c0c4df5035 100644 --- a/activerecord/CHANGELOG +++ b/activerecord/CHANGELOG @@ -1,3 +1,8 @@ +*Rails 3.0.0 [beta 4/release candidate] (unreleased)* + +* Observers can prevent records from saving by returning false, just like before_save and friends. #4087 [Mislav Marohnić] + + *Rails 3.0.0 [beta 3] (April 13th, 2010)* * Add Relation extensions. [Pratik Naik] diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb index 0fbb1f0261..ed0f039597 100644 --- a/activerecord/lib/active_record/observer.rb +++ b/activerecord/lib/active_record/observer.rb @@ -96,7 +96,8 @@ module ActiveRecord end def self.method_added(method) - self.observed_methods += [method] if ActiveRecord::Callbacks::CALLBACKS.include?(method.to_sym) + method = method.to_sym + observed_methods << method if ActiveRecord::Callbacks::CALLBACKS.include?(method) end protected @@ -104,16 +105,27 @@ module ActiveRecord observed_classes.sum([]) { |klass| klass.send(:subclasses) } end + def observe_callbacks? + self.class.observed_methods.any? + end + def add_observer!(klass) super + define_callbacks klass if observe_callbacks? + end + + def define_callbacks(klass) + existing_methods = klass.instance_methods.map(&:to_sym) + observer = self + observer_name = observer.class.name.underscore.gsub('/', '__') - # Check if a notifier callback was already added to the given class. If - # it was not, add it. self.class.observed_methods.each do |method| - callback = :"_notify_observers_for_#{method}" - if (klass.instance_methods & [callback, callback.to_s]).empty? - klass.class_eval "def #{callback}; notify_observers(:#{method}); end" - klass.send(method, callback) + callback = :"_notify_#{observer_name}_for_#{method}" + unless existing_methods.include? callback + klass.send(:define_method, callback) do # def _notify_user_observer_for_before_save + observer.update(method, self) # observer.update(:before_save, self) + end # end + klass.send(method, callback) # before_save :_notify_user_observer_for_before_save end end end -- cgit v1.2.3