Yesterday¶ ↑

The Yesterday gem lets you track changes made in ActiveRecord models. It’s also possible to diff different versions. The big difference with this gem and others (like Papertrail) is, is that it is possible to diff all child objects (has_many, belongs_to & has_and_belongs_to_many) and it’s changes.

www.youtube.com/watch?v=YgtByWlBSdA

Installation¶ ↑

Install the gem:

gem install yesterday

And then run the generator in your Rails 3 project:

rails generate yesterday:install

Use tracking in your models¶ ↑

First create model that will hold your changesets:

class Changeset < ActiveRecord::Base
  include Yesterday::ChangesetBase
end

Now assign the models you want to track:

class Contact < ActiveRecord::Base
  has_many :addresses
  track_changes :with => :changesets
end

class Address < ActiveRecord::Base
  has_many :companies
  exclude_tracking_for :associations => :companies
end

Checking version number¶ ↑

some_contact = Contact.find(10)
some_contact.version_number

Viewing historical data of an object¶ ↑

Viewing a version from an already found active record model:

some_contact = Contact.find(10)
some_contact.version(2)

Or using in a scope chain:

Contact.where(:first_name => 'foo').last.version(3)

Both of the above examples will return a Yesterday::VersionedObject

contact = Contact.create :first_name => 'foo'
contact.update_attribute :first_name => 'baz'

puts contact.version(1).first_name # -> foo
puts contact.version(2).first_name # -> baz

Diffing two versions¶ ↑

Use version numbers two compare two versions:

contact = Contact.create :first_name => 'foo'
contact.update_attribute :first_name => 'baz'

diff = contact.diff_version(1, 2)
puts diff.first_name.current # -> baz
puts diff.first_name.previous # -> foo

Diff’s within associations:

address = [Address.new(:address => 'blah')]

contact = Contact.new :first_name => 'foo'
contact.addresses = [address]
contact.save!

contact.addresses.first.address = 'blahblah'
contact.save!

diff = contact.diff_version(1, 2)
puts diff.addresses.first.address.current # -> blahblah
puts diff.addresses.first.address.previous # -> foo

To check if associations are created, just use the created_ prefix before the appropiate association:

contact.addresses.first.created?

Or, for removed associations:

contact.addresses.first.destroyed?

Or, just modified:

contact.addresses.first.modified?

Or… nothing:

contact.addresses.first.unmodified?

License and credits¶ ↑

Use it and have fun with it! Comments, cakes and hugs are welcome! Just stick to the license!

Copyright 2011, Diederick Lawson - Altovista. Released under the FreeBSD license.