Facebook SDK PHP v5 & CodeIgniter

Trying to get the latest version of Facebook SDK for PHP (v5) working well with CodeIgniter? Lucky for you, that’s what this article is all about! I’ll go over how to build a library for CodeIgniter that will help bridge the gap between CI and the Facebook SDK for PHP.

Facebook SDK PHP & CodeIgniter Libraries

Why a library? Simply put libraries are perfect to maintain separation between your local resources and the global framework resources.

Step 1. Download Facebook SDK PHP v5

The quickest & simplest way to install the Facebook SDK is via Composer. Running the following command in the application directory:

[shell]
composer require facebook/graph-sdk
[/shell]

If you already have a composer.json file and want to specify the version of the SDK you’d like to install, add a require entry:

application/composer.json

[js]
{
"require" : {
"facebook/graph-sdk" : "5.7.*"
}
}
[/js]

Navigate to the application directory and run composer install to download the required dependencies.

Step 2. Define application variables

Create a new config file in application/config for your Facebook-specific variables. This will hold your Facebook application credentials:

application/config/facebook.php

[php]
$config[‘facebook’][‘api_id’] = ‘YOUR APP ID’;
$config[‘facebook’][‘app_secret’] = ‘YOUR APP SECRET’;
$config[‘facebook’][‘redirect_url’] = ‘https://yourdomain.com/login’;
$config[‘facebook’][‘callback’] = ‘https://yourdomain.com/fb-callback’;
$config[‘facebook’][‘permissions’] = array(
’email’,
‘user_location’,
‘user_birthday’
);
[/php]

Next, you’ll need to tell CI to load the config file. Do this by opening the application/config/autoload.php file and add the following:

[php]
/*
| ——————————————————————-
| Auto-load Config files
| ——————————————————————-
| Prototype:
|
| $autoload[‘config’] = array(‘config1’, ‘config2’);
|
| NOTE: This item is intended for use ONLY if you have created custom
| config files. Otherwise, leave it blank.
|
*/

$autoload[‘config’] = array( ‘facebook’ );
[/php]

Step 3: Create the Facebook CodeIgniter library

Create a new file called Facebook.php in the application/libraries directory.

application/libraries/facebook/facebook.php

[php]
<?php if ( ! defined(‘BASEPATH’)) exit(‘No direct script access allowed’);

// Autoload the required files
require_once( APPPATH . ‘vendor/facebook/php-sdk-v4/autoload.php’ );

// Make sure to load the Facebook SDK for PHP via composer or manually

class Facebook {
var $ci;
var $accessToken;
var $fb;

public function __construct() {
// Get CI object.
$this->ci =& get_instance();

$this->fb = new \Facebook\Facebook([
‘app_id’ => $this->ci->config->item(‘app_secret’, ‘api_id’)’,
‘app_secret’ => $this->ci->config->item(‘app_secret’, ‘facebook’),
‘default_graph_version’ => ‘v2.10′,
//’default_access_token’ => ‘{access-token}’, // optional
]);
}

/**
* Get FB session.
*/
public function get_access_token() {
$helper = $this->fb->getRedirectLoginHelper();

try {
$this->accessToken = $helper->getAccessToken();
} catch( Facebook\Exceptions\FacebookResponseException $e ) {
// When Graph returns an error
echo ‘Graph returned an error: ‘ . $e->getMessage();
exit;
} catch( Facebook\Exceptions\FacebookSDKException $e ) {
// When validation fails or other local issues
echo ‘Facebook SDK returned an error: ‘ . $e->getMessage();
exit;
}
}

/**
* Login functionality.
*/
public function login() {
$this->get_access_token();
if ( $this->accessToken ) {
$this->ci->session->set_userdata( ‘fb_token’, $this->accessToken );

$user = $this->get_user();

if ( $user && !empty( $user->getProperty( ’email’ ) ) ) {
$result = $this->ci->user_model->get_user( $user->getProperty( ’email’ ) );

if ( ! $result ) {
// Not registered.
$this->ci->session->set_flashdata( ‘fb_user’, $user );
redirect( base_url( ‘register’ ) );
} else {
if ( $this->ci->user_model->sign_in( $result->username, $result->password ) ) {
redirect( base_url( ‘home’ ) );
} else {
die( ‘ERROR’ );
redirect( base_url( ‘login’ ) );
}
}
} else {
die( ‘ERROR’ );
}
}
}

/**
* Returns the login URL.
*/
public function login_url() {
$helper = $this->fb->getRedirectLoginHelper();

return $helper->getLoginUrl( $this->ci->config->item( ‘callback’, ‘facebook’ ), $this->ci->config->item( ‘permissions’, ‘facebook’ ) );
}

/**
* Returns the current user’s info as an array.
*/
public function get_user() {
$user = false;

$this->get_access_token();
if ( $this->get_access_token ) {
try {
// Get the Facebook\GraphNodes\GraphUser object for the current user.
// If you provided a ‘default_access_token’, the ‘{access-token}’ is optional.
$response = $this->fb->get( ‘/me?fields=id,name,email,first_name,last_name,birthday,location,gender’, $this->get_access_token );
} catch( Facebook\Exceptions\FacebookResponseException $e ) {
// When Graph returns an error
echo ‘ERROR: Graph ‘ . $e->getMessage();
exit;
} catch( Facebook\Exceptions\FacebookSDKException $e ) {
// When validation fails or other local issues
echo ‘ERROR: validation fails ‘ . $e->getMessage();
exit;
}
}

return $response->getGraphUser();
}

/**
* Get user’s profile picture.
*/
public function get_profile_pic( $user_id ) {
$user = $this->get_user();

if ( $user ) {
$fbID = $me->getProperty( ‘id’ );

return ‘//graph.facebook.com/’ . $fbID . ‘/picture?type=large’;
}

return false;
}
}
[/php]

The library above will give you access to the Facebook SDK Graph API. It creates and saves the Facebook token in session so you can access it later for calls to the API.

Example Usage

Once you’ve loaded the Facebook library you created above, you’ll have access to it within your controllers with the following:

[php]
$this->facebook->METHOD_NAME();
[/php]

For example, if you wanted to get the login URL (where user’s grant access):

[php]
$login_url = $this->facebook->login_url();
[/php]

Using the examples above, you should be able to add more methods to the library using the Graph API. If you need any help or run into any problems, drop me a comment below.

More on the Facebook SDK for PHP

• Facebook SDK PHP v5 — a complete guide!
• Getting started with the Facebook SDK for PHP