Error: Class 'Facebook\FacebookSession' not found with the facebook PHP SDK

Question

I am having a hard time with facebook's SDK documentation. I downloaded the SDK from Github and added it into my PHP project.

Here is the file system:

   ├── Facebook
   │   ├── FacebookAuthorizationException.php
   │   ├── FacebookCanvasLoginHelper.php
   │   ├── FacebookClientException.php
   │   ├── FacebookJavaScriptLoginHelper.php
   │   ├── FacebookOtherException.php
   │   ├── FacebookPermissionException.php
   │   ├── FacebookRedirectLoginHelper.php
   │   ├── FacebookRequest.php
   │   ├── FacebookRequestException.php
   │   ├── FacebookResponse.php
   │   ├── FacebookSDKException.php
   │   ├── FacebookServerException.php
   │   ├── FacebookSession.php
   │   ├── FacebookThrottleException.php
   │   ├── GraphLocation.php
   │   ├── GraphObject.php
   │   ├── GraphSessionInfo.php
   │   ├── GraphUser.php
   │   └── fb_ca_chain_bundle.crt
   └── test.php

here is my code so far:

use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;

FacebookSession::setDefaultApplication('*******','******');

$helper = new FacebookRedirectLoginHelper('http://isgeek.eu/fb/FaRepost/return.php');
$loginUrl = $helper->getLoginUrl();
// Use the login url on a link or button to redirect to Facebook for authentication

I get this error

Fatal error: Class 'Facebook\FacebookSession' not found in /homepages/2/d184071366/htdocs/isgeek/fb/FaRepost/test.php on line 9

At updated my PHP version, so the issue does not comme from here. It seems like the PHP files are not found. I read this question (Facebook SDK v4 for PHP Minimal Example) but it does not help.

Where does this comme from?

Answer 1

1. PHP Version 5.4.0 or higher is required.
2. Facebook uses Implementations of PSR-4. Hence You dont have to use require or require_once or include or include_once.
3. In PSR-4, you just need packagename(namespace) i.e. directory name and class file name only.It will register classes dynamically from given package name.Ex.:- use packaname\classname.
4. You will find the file autoload.php in Facebook SDK Autoload root directory.
5. use is used to load dynamic classes using spl_autoload_register
6. Facebook register all library using autoload.php or autoload_fb.php
7. You have to find autoload.php in your downloaded library like facebook-php-sdk-v4-4.0-dev/.
8. If you just wants to use Facebook library from download source.Then you have to copy autoload.php in your root directory or in Facebook directory.
9. defined constant for FACEBOOK_SDK_V4_SRC_DIR i.e. path of the facebook library
10. You need to do as below to use in php

Note: I have copied /var/www/stack/24006673/facebook-php-sdk-v4-4.0-dev/src/Facebook directory and /var/www/stack/24006673/facebook-php-sdk-v4-4.0-dev/autoload.php file in root directory /var/www/stack/24006673/

define('FACEBOOK_SDK_V4_SRC_DIR','/var/www/stack/24006673/Facebook/');
require_once("autoload.php");
use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;
use Facebook\FacebookRedirectLoginHelper;
FacebookSession::setDefaultApplication('YOUR_APP_ID','YOUR_APP_SECRET');