mongo_mapper_acts_as_tree

This is a port of classic Rails acts_as_tree to Mongo Mapper. Specify this MongoMapper plugin if you want to model a tree structure by providing a parent association and a children association. This requires that you have a foreign key, which by default is called parent_id.

It has (almost) the same functionality and passes the original test-suite. Scope needs to be defined as symbol or array of symbols. It does not work (by principle) for Embedded Documents. But in contrast to the original acts_as_tree gem inheritance is supported (in this case called Single Collection Inheritance, ActiveRecord calls it Single Table Inheritance). Please note, it is not yet optimized and therefore issues more queries than necessary.

Installation

mongo_mapper_acts_as_list is available as RubyGem:

gem install mongo_mapper_acts_as_tree

Example

class Category
  include MongoMapper::Document

  plugin MongoMapper::Plugins::ActsAsTree

  key :parent_id, ObjectId
  acts_as_tree :order => :name
end

Example:
root
 \_ child1
      \_ subchild1
      \_ subchild2

root      = Category.create(:name => "root")
child1    = root.children.create(:name => "child1")
subchild1 = child1.children.create(:name => "subchild1")

root.parent   # => nil
child1.parent # => root
root.children # => [child1]
root.children.first.children.first # => subchild1

If you want acts_as_tree to work in a Single Collection Inheritance scenario, just add :polymorphic => true to the options

class Page
  include MongoMapper::Document

  plugin MongoMapper::Plugins::ActsAsTree

  key :name, String
  key :parent_id, ObjectId
  acts_as_tree :order => :name, :polymorphic => true
end

class SubPage < Page
  key :some_irrelevant_key, String
end

Example:
root
 \_ child1
      \_ subchild1
      \_ subchild2

root      = Page.create(:name => "root")
child1    = root.children.create(:name => "child1") # creates a page
subchild1 = SubPage.create(:name => "subchild1", :parent_id => child1.id)

root.parent   # => nil
child1.parent # => root
root.children # => [child1]
root.children.first.children.first # => subchild1
subchild1.ancestors # [child1, root]

Note on Patches/Pull Requests

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright

Original Rails acts_as_tree Copyright © 2007 David Heinemeier Hansson, released under the MIT license