Using Facebook PHP-SDK 3.x to register/login user with Codeigniter 2.1.0

Question

Going over the Facebook API and I'm a bit confused on the right approach. I want users to skip registration, or auto-register them if they sign in with Facebook. So if they sign into Facebook I collect their id, email and create a record in my user table.

If an id exists already in the user table they skip the auto-registration and go directly to the members page. This is my code so far (taken from Facebook's PHP SDK example). When I run the signup script the page shows up as blank, I do not get redirected.

EDIT: seems to be failing right after the require, if I use the following code 'test' never gets printed.

EDIT: I'm using Codeigniter and this script is part of a controller, would that cause a problem with the require?

require 'http://localhost/facebook-php-sdk-6c82b3f/src/facebook.php';
echo "test";

-

public function signup()
    {   
        require 'http://localhost/facebook-php-sdk-6c82b3f/src/facebook.php';

        // Create our Application instance (replace this with your appId and secret).
        $facebook = new Facebook(array(
          'appId'  => 'xxxxxxxxxxxxxxx',
          'secret' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxx',
        ));

        // Get User ID
        $user = $facebook->getUser();

        // We may or may not have this data based on whether the user is logged in.
        //
        // If we have a $user id here, it means we know the user is logged into
        // Facebook, but we don't know if the access token is valid. An access
        // token is invalid if the user logged out of Facebook.

        if ($user)
        {
            try
            {
                // Proceed knowing you have a logged in user who's authenticated.
                $user_profile = $facebook->api('/me');
            }
            catch (FacebookApiException $e)
            {
                error_log($e);
                $user = null;
            }
        }

        // Login or logout url will be needed depending on current user state.
        if ($user)
        {
            $logoutUrl = $facebook->getLogoutUrl();
        }
        else
        {
            $loginUrl = $facebook->getLoginUrl(array('scope' => 'email'));
            redirect($loginUrl);
        }

        print_r($user_profile);


        $this->load->model("user_model");
        $privileges = 1;
        $loginLocation = ip2long($_SERVER['REMOTE_ADDR']);
        $active = 1;
        $this->user_model->add_user($user_profile->id, $user_profile->name, $user_profile->email, $loginLocation, $privileges, $active);

    }

Answer 1

I suggest you read the framework documentation. Adding a library to CodeIgniter is not a hard task. And Facebook library is no exception.

Here's a quick integration I've just come up with:

1.create a config file:application/config/facebook.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
$config['appId'] = 'app_id';
$config['secret'] = 'app_secret';

2.place the sdk files in the libraries folder application/libraries/ and rename the facebook.php file to Facebook.php and replace the php tag with this:

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

3.in your controller load the config file and then load the Facebook library:

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

class Welcome extends CI_Controller {

    public function __construct()
    {
        parent::__construct();
        // Your own constructor code
        $CI = & get_instance();
        $CI->config->load("facebook",TRUE);
        $config = $CI->config->item('facebook');
        $this->load->library('facebook', $config);
    }

    public function index()
    {
        $user = $this->facebook->getUser();
        if($user) {
            try {
                $user_info = $this->facebook->api('/me');
                echo '<pre>'.htmlspecialchars(print_r($user_info, true)).'</pre>';
            } catch(FacebookApiException $e) {
                echo '<pre>'.htmlspecialchars(print_r($e, true)).'</pre>';
                $user = null;
            }
        } else {
            echo "<a href=\"{$this->facebook->getLoginUrl()}\">Login using Facebook</a>";
        }
    }
}

Now in the constructor method, you have just initialized the Facebook library (sdk) and it can be accessed by using: $this->facebook.

Notes:

• You can always use an existing library, just google it
• A common practice is to extend the core Controller class and add the Facebook library initialization there.
• Or create another library, extend the Facebook library, load the config file there and then autoload this new library.