HabtmList
This plugin arose out of a page on the Rails wiki: wiki.rubyonrails.org/rails/pages/BetterHabtmList
The purpose is to allow position-based “acts_as_list”-like behavior in a has_and_belongs_to_many association. Methods are included to move members up and down in the list.
The original author of the technique, according to the wiki history, was “Matt.” Sorry, I don’t know his last name; I’ll give proper credit if he turns up to take it. I refactored and fixed some bugs in the code, and now I’m simply putting it up on Github. I’m claiming no ownership rights on this code whatsoever; use it any way you like.
Usage
class Category < ActiveRecord::Base
has_and_belongs_to_many :products,
:order => 'position',
:list => true end
Methods
*first?(item)* - returns true if item is first in the list *last?(item)* - returns true if item is last in the list *in_list?(item)* - returns true if item exists in the list *higher_item(item)* - returns the item one position above the given item in the list *lower_item(item)* - returns the item one position below the given item in the list *move_higher(item)* - moves the item up one position in the list *move_lower(item)* - moves the item down one position in the list *move_to_top(item)* - moves the item to the first position in the list *move_to_bottom(item)* - moves the item to the last position in the list *add_to_list_top(item)* - adds the item to the list in the first position *add_to_list_bottom(item)* - adds the item to the list in the last position *move_to_position(item, position)* - moves the item to the stated position in the list reset_positions - “first aid” method to restore list positions if positions become duplicated or go out of sync (e.g., if records are inserted or updated by external methods)
Support
I don’t promise any, but if you have any questions or complaints you’re welcome to e-mail me at [email protected].
Also check out my podcast, Escape Pod [escapepod.org], if you’re interested in science fiction short stories.
- Steve Eley