Codeigniter (very basic) ACL

acl.php

<?php

/**
* 
*/
class Acl extends CI_Model 
{
	
	protected $actions = array();


	function __construct() {
		parent::__construct();


		// define public-facing actions
		$this->add_action('build_archive',array(1,2));

		$this->add_action('edit_users',array(1));
		$this->add_action('edit_devices',array(1,2));
		
		$this->add_action('edit_title',array(1,2));
		$this->add_action('edit_messages', array(1,2));
		$this->add_action('update_order',array(1,2));
		$this->add_action('add_issue',array(1,2,3));
		
		$this->add_action('delete_issue',array(1,2));

		$this->add_action('system_menu',array(1,2));


	}

	public function can_do($action, $user_id = false){

		if ($user_id == false) {
			$user = $this->session->userdata('auth');	
		} else {
			$user = $this->user->get_by_id($user_id);
		}

		if (!is_object($user)) {
			return false;
		}

		
		$user_id 	= $user->id;
		$type 		= $user->type;

		if (in_array($action, $this->get_type_roles($type))) {
			return true;
		} else {
			return false;
		}
	}

	public function get_type_roles($type){

		$roles = array();

		switch ($type) {
			case '1':
				$roles = $this->get_roles(1);
				break;
			case '2':
				$roles = $this->get_roles(2);
				break;
			case '3':
				$roles = $this->get_roles(3);
				break;

		}

		return $roles;

	}

	public function get_roles($id){

		$roles = array();

		foreach ($this->actions as $k => $v) {
			if (in_array($id, $v)) {
				$roles[] = $k;
			}
		}

		return $roles;
	}

	// privates

	private function add_action($name = false,$roles = false){
		$this->actions[$name] = $roles;
		return true;
	}

}