History

Cody Cutrer 48864de3f6 begin rails 4 enough for bundle install to work with 4.1.5 Change-Id: I277df9e4315fa250b6028139113c74721148e2f0 Reviewed-on: https://gerrit.instructure.com/39656 Reviewed-by: Brian Palmer <brianp@instructure.com> Tested-by: Jenkins <jenkins@instructure.com> Product-Review: Cody Cutrer <cody@instructure.com> QA-Review: Cody Cutrer <cody@instructure.com>		2014-08-27 23:09:17 +00:00
..
lib/active_support/callbacks	fix callback suspension for ruby 2	2014-06-23 22:01:05 +00:00
spec	spec: simple_cov vendored_gems report merging	2014-02-28 09:04:50 +00:00
.rspec	ActiveSupport::Callbacks::Suspension	2014-02-19 20:20:00 +00:00
Gemfile	begin rails 4	2014-08-27 23:09:17 +00:00
LICENSE.txt	ActiveSupport::Callbacks::Suspension	2014-02-19 20:20:00 +00:00
README.md	ActiveSupport::Callbacks::Suspension	2014-02-19 20:20:00 +00:00
Rakefile	ActiveSupport::Callbacks::Suspension	2014-02-19 20:20:00 +00:00
activesupport-suspend_callbacks.gemspec	begin rails 4	2014-08-27 23:09:17 +00:00
test.sh	remove rails 2 support	2014-08-06 18:16:19 +00:00

README.md

Suspend Callbacks

ActiveSupport's Callbacks module allows you to define a callback hook and then register methods to be run before/after/around that hook.

It also let's you skip callbacks in a specific context. For example, ActiveRecord::Base defines a callback hook around save. My top level Person model may register an :ensure_privacy method to run before save. But the Celebrity model that inherits from Person can then skip that callback. End result: when I save a john_doe Person object, :ensure_privacy will run, but when I save the dhh Celebrity object, it won't.

But what if you want to suspend callbacks, regardless of subclass, but only for a duration of time? That's when you want to suspend callbacks.

Example

class MyModel < ActiveRecord::Base include ActiveSupport::Callbacks::Suspension

before :save, :expensive_callback after :save, :other_callback

def expensive_callback # stuff end

def other_callback # stuff end end

instance1 = MyModel.new instance2 = MyModel.new

MyModel.suspend_callbacks do

neither callback will run for either instance

instance1.save instance2.save end

MyModel.suspend_callbacks(kind: :save) do

same

instance1.save instance2.save end

MyModel.suspend_callbacks(:expensive_callback) do

expensive_callback won't run, but other_callback will

instance1.save instance2.save end

MyModel.suspend_callbacks(type: :before) do

same

instance1.save instance2.save end

instance1.suspend_callbacks do

callbacks won't run this time...

instance1.save

... but they will this time.

instance2.save end