ActsAsArchival

Atomically archive object trees in your activerecord models.

We had the problem that acts_as_paranoid and similar plugins/gems always work on a record by record basis and made it very difficult to restore records atomically (or archive them, for that matter).

Because the archive and unarchive methods are in transactions, and every archival record involved gets the same archive number upon archiving, you can easily restore or remove an entire set of records without having to worry about partial deletion or restoration.

Additionally, other plugins generally screw with how destroy/delete work. We don't because we actually want to be able to destroy records.

Install

Rails 3.2+ (maybe 3.1?)

gem install acts_as_archival

Rails 3.0x:

rails plugin install http://github.com/expectedbehavior/acts_as_archival.git -r rails3.0x

Rails 2:

script/plugin install http://github.com/expectedbehavior/acts_as_archival.git -r rails2

Any models you want to be archival should have the columns archive_number(String) and archived_at (DateTime).

i.e. script/generate migration AddAAAToPost archive_number:string archived_at:datetime

Any dependent-destroy objects connected to an AAA model will be archived with its parent.

Example

class Hole < ActiveRecord::Base
  acts_as_archival
  has_many :moles, :dependent => :destroy
end

class Mole < ActiveRecord::Base
  acts_as_archival
end

>> Hole.archived.size               # => 0
>> Hole.is_archival?                # => true
>> h = Hole.create
>> Hole.unarchived.size             # => 1
>> h.is_archival?                   # => true
>> h.archived?                      # => false
>> h.muskrats.create
>> h.archive                        # archive hole and muskrat
>> h.archive_number                 # => 8c9f03f9d....
>> h.muskrats.first.archive_number  # => 8c9f03f9d....
>> h.archived?                      # => 8c9f03f9d....
>> Hole.archived.size               # => 1
>> Hole.unarchived.size             # => 0
>> h.unarchive
>> Hole.archived.size               # => 0
>> Hole.unarchived.size             # => 1

Caveats

This will only work on associations that are dependent destroy. It should be trival to change that or make it optional.
It will only work for Rails 2.2 and up, because we are using named_scope/scope. You can check out permanent records for a way to conditionally add the functionality to older Rails installations.
This will only work (well) on databases with transactions (mysql, postgres, etc.).

Testing

Because this plugin makes use of transactions we're testing it on MySQL instead of the more convenient sqlite. Running the tests should be as easy as:

bundle
test/script/db_setup    # makes the databases with the correct permissions (for mySQL)
rake

Help Wanted

It would be cool if someone could check if this thing works on postgres and if not, submit a patch / let us know about it!

Thanks

ActsAsParanoid and PermanentRecords were both inspirations for this
http://github.com/technoweenie/acts_as_paranoid
http://github.com/fastestforward/permanent_records

Contributors

Joel Meador
Michael Kuehl
Matthew Gordon
Vojtech Salbaba
David Jones
Dave Woodward

Thanks!

kgorin/acts_as_archival