Intergrate facebook php sdk v4 with CodeIgniter Framewrok.

Using composer to install Facebook SDK

$ composer install

Update your Facebook App id and secret on config/facebook.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

$config['facebook_app_id'] = 'xxxxxxxxxxxxxxxxxxx';
$config['facebook_api_secret'] = 'xxxxxxxxxxxxxxxxxxx';

Open your browser and connect http://localhost/index.php/login/facebook