canvas-lms/gems/activesupport-suspend_callb...
Cody Cutrer e42c68d1af fix backtraces for callbacks
without a __FILE__ passed to instance_eval with a string, ruby wasn't
giving backtraces for anything below, even after calling back to non-evaled
code

Change-Id: Iee74423f7839bbbb44c9a3761220a045d8071681
Reviewed-on: https://gerrit.instructure.com/57377
Tested-by: Jenkins
Reviewed-by: Ethan Vizitei <evizitei@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
2015-06-29 22:34:32 +00:00
..
lib/active_support/callbacks fix backtraces for callbacks 2015-06-29 22:34:32 +00:00
spec fix Style/EmptyLineBetweenDefs issue 2015-04-29 16:28:39 +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 do some cleanup on gem test runs 2015-05-18 22:39:17 +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