AcceptsNestedIds

You want to save associations (has_many or has_many :through) by ID, but Rails is totally not doing what you expect it to.

This gem.

Let's take a typical scenario.

class Project < ActiveRecord::Base
  has_many :project_users
  has_many :users, through: :project_users
  validates :name, presence: true
  attribute :user_ids
end

When creating or updating a Project, you can select a list of User IDs from a select list. Great.

project = Project.first
project.name = ""
project.user_ids = [1,2,3]
project.save!

Oh shit.

Thats right: Rails went ahead and associated those Users, even through the save failed. Because it didn't even wait until the save! to associate them. It happened right here: project.user_ids = [1,2,3]

No one wants this. But it happens all the time.

AcceptsNestedIds defers the saving of ID-based associations to a model's after_save callback. In the example above, no User associations would have been created when using this gem.

Ever need audit trail functionality? Its easy, using ActiveModel::Dirty and its related methods (changes?, etc). However, what you won't get out-of-the-box is dirty tracking for associated attributes. Because why would you?

AcceptsNestedIds adds dirty tracking for ID-based associations:

project = Project.first
project.user_ids = [1,2,3]
project.changes # => "user_ids" => [[], [1,2,3]]

Beauty.

Add this line to your application's Gemfile:

gem 'accepts_nested_ids'

And then execute:

$ bundle

Or install it yourself as:

$ gem install accepts_nested_ids

class Project < ActiveRecord::Base
  include AcceptsNestedIds
  has_many :project_users
  has_many :users, through: :project_users
  accepts_nested_ids_for :users
  attribute :user_ids
end

project.user_ids = [...]

class Project < ActiveRecord::Base
  include AcceptsNestedIds
  has_many :project_users
  has_many :included_users, through: :project_users, source: :user
  accepts_nested_ids_for included_users: "User"
  attribute :user_ids
end

project.included_user_ids = [...]

When using a custom association name, you must specify the actual class name as a second arg, in this case "User".

class Project < ActiveRecord::Base
  include AcceptsNestedIds
  has_many :documents
  has_many :project_users
  has_many :included_users, through: :project_users, source: :user
  accepts_nested_ids_for :documents, included_users: "User"
  attribute :user_ids
end

project.document_ids = [...]
project.included_user_ids = [...]

After checking out the repo, run bin/setup to install dependencies. Then, run rake rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Requires Activemodel & Activerecord 6.1.1 or higher

Bug reports and pull requests are welcome on GitHub at https://github.com/uberllama/accepts_nested_ids.

The gem is available as open source under the terms of the MIT License.