Mongoid Listable is a library for managing listable relations. It works great for non-relational collections or for more complex has_many / embeds_many relationships.
There are two main macros:
listedfor non-relational lists that do not belong to any objects.listsforhas_many/embeds_manyrelationships.
class Photo
include Mongoid::Document
include Mongoid::Listable
listed
...
end
The listed macro will assign a position field and a list scope to the Photo class. All Photo instances that are
created, destroyed, or have their position field updated will trigger a reording of all sibling instances.
Non-relational lists can have as many listed contexts as needed. You'll need to specify both the scope and the
field options in these cases.
class Photo
include Mongoid::Document
include Mongoid::Listable
listed :scope :list, field: :position
listed :scope :slideshow, field: :slideshow_position
...
end
Photo.list # orders by position field
Photo.slideshow # orders by slideshow_position
class User
include Mongoid::Document
include Mongoid:Listable
has_many :photos
# or embeds_many :photos
lists :photos
...
end
class Photo
include Mongoid::Document
belongs_to :user
# or embedded_in :user
...
end
In this example photos that are added to or removed from a user's collection, or have their position attribute updated will trigger a reordering of all sibling instances. For example:
# setter
User.first.photos = [ photo_a, photo_c, photo_b ]
User.first.photos.last == photo_b #=> true
# ids setter
User.first.photo_ids = [ '527fe97c67df6f07e1000003', '527fe97c67df6f07e1000004', '527fe97c67df6f07e1000003' ]
User.first.photos[1].id == '527fe97c67df6f07e1000004' #=> true
# push
photo = Photo.create
User.first.photos << photo
User.first.photos.last == photo #=> true
Each photo that belongs to the user will automatically obtain a field called user_position. The field name
is derived from the foreign key of the relation, replacing "_id" with "_position".
The has_many / embeds_many relationship of a user to their photos will automadtically be ordered by user_position unless otherwise specified
via the standard order option to the has_many macro.
# Handles multiple has_many relations on same model!
class User
include Mongoid::Document
include Mongoid:Listable
has_many :featured_photos,
class_name: 'Photo',
inverse_of: :featured_by_user,
foreign_key: :featured_by_user_id
has_many :kodak_moments,
class_name: 'Photo',
inverse_of: :kodaked_by_user,
foreign_key: :kodaked_by_user_id
lists :featured_photos
lists :kodak_moments
...
end
class Photo
include Mongoid::Document
belongs_to :featured_by_user,
class_name: 'User',
inverse_of: featured_photos,
foreign_key: :featured_by_user_id
belongs_to :kodaked_by_user,
class_name: 'User',
inverse_of: kodak_moments,
foreign_key: :kodaked_by_user_id
...
end
In this example, there are two has_many relations defined between a user and photos. Each photo belonging to a user will
obtain two position fields: featured_by_user_position and kodaked_by_user_position.
Add this line to your application's Gemfile:
gem 'mongoid_listable'
And then execute:
$ bundle
Or install it yourself as:
$ gem install mongoid_listable
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request