An ActiveRecord/Rails library to add before_commit, after_commit, before_rollback and after_rollback callbacks. These callbacks are focused on the transactions, instead of specific model actions. This is beneficial in situations where you are doing asynchronous processing and need committed objects.

Please note: Rails 3 (and thus, ActiveRecord 3) provides commit callbacks natively, so this library will remain just for versions 1.2.x to 2.x of ActiveRecord.

gem install after_commit

The following callbacks are provided:

• before_commit
• before_commit_on_create
• before_commit_on_update
• before_commit_on_destroy
• after_commit
• after_commit_on_create
• after_commit_on_update
• after_commit_on_destroy
• before_rollback
• after_rollback

You can use these just like you would any other callback:

class Article < ActiveRecord::Base
  after_commit :method_to_call_after_commit
  
  # ...
  
  private
  
  def method_to_call_after_commit
    # Do something knowing that the transaction is committed.
  end
end

Keep in mind that transactions are finicky at best in tests, and so there’s a helper module to make after_commit play nicely in your testing context. You’ll need to add these two lines to your spec/test helper:

ActiveRecord::Base.send(:include, AfterCommit::AfterSavepoint)
ActiveRecord::Base.include_after_savepoint_extensions

This code first appeared in a blog post by Eli Miller, and was then included in Thinking Sphinx by Pat Allan, with modifications from Joost Hietbrink. The code was then put on GitHub as a plugin by Nick Muerdter, and many people forked and added their own contributions.

This version (maintained by Pat Allan) includes the following patches:

• Callbacks for specific types of actions (create, update, destroy) (DeLynn Berry)
• Fixes to extra callbacks (Xavier Shay)
• Thread-safety (Dmitry Galinsky)
• after_rollback callback (Justin Balthrop)
• Test environment fix (Pivotal Labs)
• Scoping callbacks to specific connections (Mat Brown)
• before_* callbacks (Trotter Cashion)
• Gemspec and extended tests, works as a plugin, doesn’t load ActiveRecord hooks twice, doesn’t add Test environment hook automatically. (David Yip)
• Exception propagation (George Ogata)
• Keeping callbacks focused on the correct transactions (Benjamin Stein)
• Using savepoints for test helper (Lars Klevan and Joel Chippindale)
• Only tracking objects from classes that have appropriate callbacks; Adding after/before_commit_on_save to cover creates and updates but not destroys (Jason Weathered)
• Fixing up exception handling and savepoints in the test helper, and cleaning up successful transactions correctly (Identified).
• Improved JRuby support (Kevin Menard)
• Stop transaction failures in tests (Ochko)