Connect with Facebook in CI

Note: This post is very old, please use Facebook SDK4 at https://github.com/facebook/facebook-php-sdk-v4 for implementing Connect with Facebook or for using Facebook graph API in your websites.

Follow the below simple steps and implement Connect with Facebook in your website.

1. Create a Config file in application/facebook.php with the following code in it.

$config['appId'] = 'Your Facebook App ID'; $config['secret'] = 'Your secret Code';

1. There is two files provided starting from V.3.0.0 of Facebook PHP SDK. Create a folder in application library and name it as facebook.
2. Download the Facebook PHP SDK files and place it in the folder application/library/facebook. You can download it from https://github.com/facebook/php-sdk
3. Create a new file and name it as fb_connect.php in application/library and copy the following code inside that folder.

<?php 
include(APPPATH.'libraries/facebook/facebook.php'); 
class Fb_connect extends Facebook
{
    //declare public variables 
    public $user = NULL; 
    public $user_id = FALSE; 
    public $fb = FALSE;
    public $fbSession = FALSE; 
    public $appkey = 0; 

    //constructor method. 
    public function __construct() { 
        $CI = & get_instance(); 
        $CI->config->load("facebook",TRUE); 
        $config = $CI->config->item('facebook'); 
        parent::__construct($config); 
        $this->user_id = $this->getUser(); // New code 
        $me = null; 
        if ($this->user_id) 
        { 
            try 
            {
                $me = $this->api('/me'); 
                $this->user = $me; 
            } 
            catch (FacebookApiException $e) 
            {
                error_log($e); 
            }
        }
    } 
} // end class 

Now create a Controller and name it as user, and write the following methods in it.

function loginByFacebook()
{
    $this->load->library('fb_connect'); 
    $param['redirect_uri']=site_url("user/facebook"); 
    redirect($this->fb_connect->getLoginUrl($param)); 
} 

function facebook()
{
    $this->load->library('fb_connect');
    if (!$this->fb_connect->user_id) 
    { 
        //Handle not logged in,
    } 
    else 
    { 
        $fb_uid = $this->fb_connect->user_id; 
        $fb_usr = $this->fb_connect->user; 
        //Hanlde user logged in, you can update your session with the available data         
        //print_r($fb_usr) will help to see what is returned 
    }
}

You are done with coding now. Now when ever user need to login with facebook just redirect them to user/loginByFacebook and the login will handled automatically by Facebook. But you need to update the facebook() method with the actions success and failure conditions.