PHP DjangoUser class

django_session.php

<?PHP
/*
  DjangoUser object to Joomla in PHP. 
  (Can be adapted easily to other PHP frameworks)

  Usage::

    $user =& DjangoUser::getUser();

    if ($user && $user->hasPerm("polls.can_vote")) {
       echo "I can vote!";
    }
*/

class DjangoUser {
	static $instance = NULL;
	function __construct($userid) {
		$this->id = $userid;
		
		if ($userid)
			$this->fetchFromDB();
	}
	
	private function fetchFromDB() {
		
		$db =& \JFactory::getDBO();
		$sql = <<<SQL
			SELECT 
				usr.*, 
				GROUP_CONCAT( DISTINCT CONCAT_WS(".", dcon.app_label, per.codename) ) AS perms 
			FROM auth_user as usr 
			LEFT JOIN auth_user_user_permissions AS usrprms ON usrprms.user_id = usr.id 
			LEFT JOIN auth_user_groups as usrgrp ON usr.id = usrgrp.user_id 
			LEFT JOIN auth_group as grp ON usrgrp.group_id = grp.id 
			LEFT JOIN auth_group_permissions as grpper ON grpper.group_id = grp.id 
			LEFT JOIN auth_permission as per ON per.id = grpper.permission_id OR per.id = usrprms.permission_id 
			LEFT JOIN django_content_type as dcon ON dcon.id = per.content_type_id 
			WHERE usr.id = {$db->Quote($this->id)} 
			GROUP BY usr.id 
SQL;
		$db->setQuery($sql);
		
		if ($userdb = $db->loadObject()) {
			
			$this->username = $userdb->username;
			$this->first_name = $userdb->first_name;
			$this->last_name = $userdb->last_name;
			$this->email = $userdb->email;
			$this->is_staff = $userdb->is_staff;
			$this->is_active = $userdb->is_active;
			$this->is_superuser = $userdb->is_superuser;
			$this->last_login = $userdb->last_login;
			$this->date_joined = $userdb->date_joined;
			$this->perms = array();
			
			$perms = explode(",", $userdb->perms);
			
			foreach ($perms as $perm) {
				if ($perm) {
					list($app, $perm) = explode(".", $perm);
					
					if (!isset($this->perms[$app]))
						$this->perms[$app] = array();
						
					$this->perms[$app][] = $perm;
				}
			}
		}
	}
	
	public function hasPerm($appPerm, $object=NULL) {
		if ($this->is_superuser)
			return true;
			
		list($app, $perm) = explode(".", $appPerm);
		
		if (isset($this->perms[$app]) && in_array($perm, $this->perms[$app]))
			return true;
			
		return false;
	}
	
	public function hasPerms($appPerms, $object=NULL) {
		if ($this->is_superuser)
			return true;
			
		foreach ($appPerms as $appPerm)
			if (!$this->hasPerm($appPerm, $object))
				return false;
	
		return true;
	}
	
	public function hasAnyPerm($appPerms, $object=NULL) {
		if ($this->is_superuser)
			return true;

		foreach ($appPerms as $appPerm) {
			if ($this->hasPerm($appPerm, $object))
				return true;
		}
		
		return false;
	}
	
	public function hasModulePerms($appLabel) {
		if ($this->is_superuser)
			return true;	
			
		if (isset($this->perms[$appLabel]))
			return true;
			
		return false;
	}
	
	private static function _fromSession() {
		$sid = \JRequest::getString("sessionid", "", "COOKIE");
		
		if (!$sid)
			return new DjangoUser();
		
		$db =& \JFactory::getDBO();
		$db->setQuery("SELECT "
			."* FROM django_session "
			."WHERE session_key = {$db->Quote($sid)} "
		."");
		
		$session_table = $db->loadObject();
		
		if (!$session_table)
			return new DjangoUser();
			
		$session_json = substr($session_table->session_data, 0, -32);
		$session_data = json_decode($session_json);
		
		if (isset($session_data->_auth_user_id))
			return new DjangoUser($session_data->_auth_user_id);
	}
	
	public static function getUser() {
		if (self::$instance !== NULL)
			return self::$instance;
		self::$instance = &DjangoUser::_fromSession();
		return self::$instance;
	}
}