SortableElementForNestedSet

Sorting a tree using the script.aculo.us helper that comes with Rails is nice. But if your tree is backed by a nested set, the default request parameter sent to your controllers might not really fit your needs.

This plugin allows you to easily find out which html element was moved (dragged) and between which two elements it ended up.

Your work will be to make the update to your nested set model.

Usage

The plugin has two parts. One view helper method and one controller module.

Assuming you have a tree where the node elements are named using the dom_id helper method, in your view, use the sortable_element_reporting_target helper pretty much as your would use the sortable_element helper that comes with Rails. There is however a second argument that sets the parameter name of where the (record) id of the element that was moved will be available. The third (optional) options argument is the same as for sortable_element, except that :onChange and :with are not allowed.

<%= sortable_element_reporting_target("tree_element", "moved_element_id") %>

In your controller, include the util methods with handles_sorting_of_nested_set. To get the new position of a moved element use the these methods in a similar way to this example controller:

class MyController < ApplicationController handles_sorting_of_nested_set

def move new_position = position_of(:moved_element_id).in_tree(:tree_element) end end

The new_position variable will be a hash with information about the moved elements new position. The keys in the hash (:parent, :move_to_right_of, :move_to_left_of) all point to active record id:s. It up to you to move your model accordingly.

For a more complete sample, the relevant parts of a simple rails application can be found in this gist.

Install

As gem

Add the following to config/environment.rb

config.gem “robinsp-sortable_element_for_nested_set”, :lib => “sortable_element_for_nested_set”, :source => “gems.github.com”

Then run

sudo rake gems:install

As plugin

./script/plugin install git://github.com/robinsp/sortable_element_for_nested_set.git