Codeigniter Facebook SDK Tutorials : create facebook application using codeigniter

<?php
$config['facebook_app_id'] = 'your app_id';
$config['facebook_api_secret']='your app secret id';
$config['facebook_default_scope']='email,user_birthday,user_location,photo_upload, 
user_photos,user_photo_video_tags,user_work_history,user_about_me,user_hometown';
$config['facebook_api_url'] = 'https://graph.facebook.com/'; // Just in case it changes.
</php>

$this->load->config('facebook');
                $this->_api_url 	= $this->config->item('facebook_api_url');
		$this->_api_key 	= $this->config->item('facebook_app_id');
		$this->_api_secret 	= $this->config->item('facebook_api_secret');
		$this->_default_scope	= $this->config->item('facebook_default_scope');
		$config = array(
					'appId'  => $this->_api_key,
					'secret' => 	$this->_api_secret,
					'fileUpload' => true, // Indicates if the CURL based @ syntax for file uploads is enabled.
				);
		$this->load->library('Facebook', $config);//load facebook library for facebook sdk

function get_user(){//return the facebook user id
		return $this->_user=$this->facebook->getUser();
	}

function get_login_url(){//return the facebook login url. like to change the scope of loginUrl(config/facebook.php)
	return  $this->facebook->getLoginUrl(
            array(
                'scope'         => $this->_default_scope
            )
    );
}

function get_logout_url(){//return the facebook logoutUrl
 
	return  $this->facebook->getLogoutUrl();
}