ActsAsParanoidDag

WARNING: THIS GEM DOES NOT WORK AS EXPECTED. DO NOT USE IT.

There are some issues concerning the count of indirect links, which could make the dag unusable. We're currently investigating possible solutions.

acts_as_paranoid_dag is a ruby on rails gem that combines the gems acts-as-dag and rails3_acts_as_paranoid to order model instances in a polymorphic directed acyclic graph and to be able to retrieve connections deleted in the past.

For example, I'm using this to have a user-group structure, where I can query for group memberships deleted in the past.

Add this line to your application's Gemfile:

gem 'acts_as_paranoid_dag'

And then execute:

$ bundle

Or install it yourself as:

$ gem install acts_as_paranoid_dag

I'm assuming that you would like to extend the functionality of your existing DagLink model. That is, you already have a model DagLink.

class DagLink < ActiveRecord::Base
  acts_as_dag_links polymorphic: true
end

In your DagLink model, you'll need an extra column for saving the datetime of deletion.

$ bundle exec rails generate migration AddDeletedAtToDagLink deleted_at:datetime
$ rake db:migrate

Have a look at this database schema from the gem's specs.

In your DagLink model, just add the option paranoid: true.

class DagLink < ActiveRecord::Base
  acts_as_dag_links polymorphic: true, paranoid: true
end

Then you can retrieve links using the scopes now, ìn_the_past and now_and_in_the_past.

# create link between user and group, just as in acts-as-dag
group1 = Group.create( ... )
group2 = Group.create( ... )
user = User.create( ... )
group1.child_users << user
user.links_as_child.first.destroy
group2.child_users << user

# now use the new scopes
user.links_as_child.now.count # => 1
user.links_as_child.in_the_past.count # => 1
user.links_as_child.now_and_in_the_past.count # => 2
user.links_as_child.at_time( 1.hour.ago ).count # => 0

# deleting links
link = user.links_as_child.now.first
link.destroy  # mark this link as deleted, but leave it in the database
link.destroy!  # really delete the link from the database
link.destroy_permanently  # same as destroy!

(You don't need to call destroy before calling destroy_permanently or destroy!, but you can.)

You may want to have a look at these specs.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request