Nested Sets Behavior for Yii 2

A modern nested sets behavior for the Yii framework utilizing the Modified Preorder Tree Traversal algorithm.

Installation

The preferred way to install this extension is through composer.

Either run

$ php composer.phar require creocoder/yii2-nested-sets:dev-master

or add

"creocoder/yii2-nested-sets": "dev-master"

to the require section of your composer.json file.

Migrations

Run the following command

$ yii migrate/create create_menu_table

Open the /path/to/migrations/m_xxxxxx_xxxxxx_create_menu_table.php file, inside the up() method add the following

$this->createTable('{{%menu}}', [
    'id' => Schema::TYPE_PK,
    // 'tree' => Schema::TYPE_INTEGER,
    'lft' => Schema::TYPE_INTEGER . ' NOT NULL',
    'rgt' => Schema::TYPE_INTEGER . ' NOT NULL',
    'depth' => Schema::TYPE_INTEGER . ' NOT NULL',
    //...
]);

To use multiple tree mode uncomment tree field.

Configuring

Configure model as follows

use creocoder\nestedsets\NestedSetsBehavior;

class Menu extends \yii\db\ActiveRecord
{
    public function behaviors() {
        return [
            'class' => NestedSetsBehavior::className(),
            // 'treeAttribute' => 'tree',
            // 'leftAttribute' => 'lft',
            // 'rightAttribute' => 'rgt',
            // 'depthAttribute' => 'depth',
        ];
    }

    public function transactions()
    {
        return [
            self::SCENARIO_DEFAULT => self::OP_ALL,
        ];
    }

    public static function find()
    {
        return new MenuQuery(get_called_class());
    }
}

To use multiple tree mode uncomment treeAttribute array key inside behaviors() method.

Configure query class as follows

use creocoder\nestedsets\NestedSetsQueryBehavior;

class MenuQuery extends \yii\db\ActiveQuery
{
    public function behaviors() {
        return [
            NestedSetsQueryBehavior::className(),
        ];
    }
}

Usage

Making a root node

To make a root node

$countries = new Menu(['name' => 'Countries']);
$countries->makeRoot();

The tree will look like this

- Countries

Prepending a node as the first child of another node

To prepend a node as the first child of another node

$russia = new Menu(['name' => 'Russia']);
$russia->prependTo($countries);

The tree will look like this

- Countries
    - Russia

Appending a node as the last child of another node

To append a node as the last child of another node

$australia = new Menu(['name' => 'Australia']);
$australia->appendTo($countries);

The tree will look like this

- Countries
    - Russia
    - Australia

Inserting a node before another node

To insert a node before another node

$newZeeland = new Menu(['name' => 'New Zeeland']);
$newZeeland->insertBefore($australia);

The tree will look like this

- Countries
    - Russia
    - New Zeeland
    - Australia

Inserting a node after another node

To insert a node after another node

$unitedStates = new Menu(['name' => 'United States']);
$unitedStates->insertAfter($australia);

The tree will look like this

- Countries
    - Russia
    - New Zeeland
    - Australia
    - United States

Getting the root nodes

To get all the root nodes

$roots = Menu::find()->roots()->all();

Getting the leaves nodes

To get all the leaves nodes

$leaves = Menu::find()->leaves()->all();

To get all the leaves of a node

$countries = Menu::findOne(['name' => 'Countries']);
$leaves = $countries->leaves()->all();

Getting children of a node

To get all the children of a node

$countries = Menu::findOne(['name' => 'Countries']);
$children = $countries->children()->all();

To get the first level children of a node

$countries = Menu::findOne(['name' => 'Countries']);
$children = $countries->children(1)->all();

Getting parents of a node

To get all the parents of a node

$countries = Menu::findOne(['name' => 'Countries']);
$parents = $countries->parents()->all();

To get the first parent of a node

$countries = Menu::findOne(['name' => 'Countries']);
$parent = $countries->parents(1)->one();