has_hierarchy

Tree behavior for ActiveRecord models and Mongoid documents.

Installation

Add this line to your application's Gemfile:

gem 'has_hierarchy'

And then execute:

$ bundle

Usage

Example model:

$ rails g model Item \
  name:string \
  path:string \
  depth:integer \
  position:integer \
  parent:belongs_to \
  children_count:integer

class Item < ActiveRecord::Base
  has_hierarchy path_part: :name,
                depth_cache: true,
                counter_cache: true,
                dependent: :destroy
end

or Mongoid document:

class Item
  include Mongoid::Document
  include Mongoid::HasHierarchy

  has_hierarchy path_part: :name,
                depth_cache: true,
                counter_cache: true,
                dependent: :destroy

  field :name,  type: String
  field :path,  type: String
  field :depth, type: Fixnum, default: 0
  field :children_count, type: Fixnum, default: 0
end

Options:

scope          - optional, proc, symbol or an array of symbols.
order          - optional, column name or boolean, default :position.
path_cache     - optional, column name or boolean, default :path.
path_part      - optional, column name, default :id.
path_separator - optional, string, default '/'.
depth_cache    - optional, column name or boolean, default :depth.
counter_cache  - optional, :counter_cache option for parent association.
dependent      - optional, :dependent option for children association.

Operations on the tree:

foo = Item.create!(name: 'foo')
bar = Item.create!(name: 'bar')
qux = bar.children.create!(name: 'qux')
baz = bar.children.create!(name: 'baz')
quux = qux.children.create!(name: 'quux')

Item.roots
# => [ foo, bar ]

Item.ordered.tree
# => {
#   foo => {},
#   bar => {
#     qux => {
#       quux => {}
#     },
#     baz => {}
#   }
# }

quux = Item.find_by_path('bar/qux/quux')
# => quux
quux.full_path
# => 'bar/qux/quux'

Operations on nodes:

bar.children         # => [ qux, baz ]
qux.parent           # => bar
foo.siblings         # => [ bar ]
bar.parent_of?(quux) # => false
qux.child_of?(bar)   # => true
bar.sibling_of?(foo) # => true
bar.root?            # => true
qux.leaf?            # => false

Ancestors/descendants (requires path_cache):

bar.root_of?(quux)      # => true
bar.ancestor_of?(quux)  # => true
qux.descendant_of?(bar) # => true
quux.root               # => bar
quux.ancestors          # => [ qux, bar ]
bar.descendants         # => [ qux, quux, baz ]

Ordering (see has_order):

bar.previous_siblings  # => [ foo ]
foo.next_siblings      # => [ bar ]

foo.move_after(quux)
Item.ordered.tree
# => {
#   bar => {
#     qux => {
#       quux => {},
#       foo => {}
#     },
#     baz => {}
#   }
# }

License

Copyright (c) 2014 Kolesnikov Danil

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.