Facebook Connect with PHP SDK v4
Since my last post about Facebook connect back in 2012, Facebook still remains the top user registration source, well at-least in my imagination! And recently they have released PHP SDK version 4 with significant changes. So, today we are going to talk about it a bit and try and create a working Facebook Sign-Up page using their SDK v4. The Facebook SDK 4 version requires PHP 5.4 or greater, so if you are still on prior PHP versions, you might face problems with this SDK, this is mostly because of new Autoloader in PHP Library utilized by all PHP packages these days. So either you have to upgrade your PHP or use earlier SDK version for time being.Connect to Facebook
Despite all the changes in the SDK, the process of implementation is still same and easy. You can download Facebook SDK 4.0 here, extract the package anywhere within your project folder, and include autoload.php in your project, take a look at a working example below :PHP
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<?php
session_start(); //Session should be active
$app_id = '453598374'; //Facebook App ID
$app_secret = '934729857443983230943'; //Facebook App Secret
$required_scope = 'public_profile, publish_actions, email'; //Permissions required
$redirect_url = 'http://localhost/facebook-connect/'; //FB redirects to this page with a code
//include autoload.php from SDK folder, just point to the file like this:
require_once __DIR__ . "/facebook-php-sdk-v4-4.0-dev/autoload.php";
//import required class to the current scope
use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRedirectLoginHelper;
FacebookSession::setDefaultApplication($app_id , $app_secret);
$helper = new FacebookRedirectLoginHelper($redirect_url);
//try to get current user session
try {
$session = $helper->getSessionFromRedirect();
} catch(FacebookRequestException $ex) {
die(" Error : " . $ex->getMessage());
} catch(\Exception $ex) {
die(" Error : " . $ex->getMessage());
}
if ($session){ //if we have the FB session
$user_profile = (new FacebookRequest($session, 'GET', '/me'))->execute()->getGraphObject(GraphUser::className());
//do stuff below, save user info to database etc.
echo '<pre>';
print_r($user_profile); //Or just print all user details
echo '</pre>';
}else{
//display login url
$login_url = $helper->getLoginUrl( array( 'scope' => $required_scope ) );
echo '<a href="'.$login_url.'">Login with Facebook</a>';
}Fetch User Details
Once the user details are available in $user_profile variable, you should know what to do next with that information. But the user data is enclosed in a protected GraphUser object, and if you try to access it usual way, you will encounter Cannot access protected property Facebook\GraphUser error. Here’s a sample of GraphUser object for the current user.123456789101112131415161718192021222324
Facebook\GraphUser Object
(
[backingData:protected] => Array
(
[id] => 102417138XXXX
[birthday] => 03/04/1990
[first_name] => Fred
[email] => [email protected]
[gender] => male
[last_name] => TestMan
[link] => http://www.facebook.com/102417138XXXX
[location] => stdClass Object
(
[id] => 102417138XXXX
[name] => Middle Earth, Maryland
)
[locale] => en_US
[name] => Fred TestMan
[timezone] => 5.0
[updated_time] => 2013-01-26T20:22:46+0000
[verified] => 1
)
)PHP
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if ($session){ //if we have the FB session
$user_profile = (new FacebookRequest($session, 'GET', '/me'))->execute()->getGraphObject(GraphUser::className());
echo $user_profile->getProperty('id');
echo $user_profile->getProperty('name');
echo $user_profile->getProperty('first_name');
echo $user_profile->getProperty('last_name');
}PHP
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if ($session){ //if we have the FB session
$user_profile = (new FacebookRequest($session, 'GET', '/me'))->execute()->getGraphObject(GraphUser::className());
echo $user_profile->getId();
echo $user_profile->getName();
echo $user_profile->getFirstName();
echo $user_profile->getMiddleName();
echo $user_profile->getLastName();
echo $user_profile->getLink();
echo $user_profile->getBirthday();
echo $user_profile->getLocation();
}PHP
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if ($session){ //if we have the FB session
$user_profile = (new FacebookRequest($session, 'GET', '/me'))->execute()->getGraphObject(GraphUser::className())->asArray();
echo $user_profile["id"];
echo $user_profile["name"];
echo $user_profile["first_name"];
echo $user_profile["last_name"];
}Upload an image on User Wall
You don’t always want to get user data from Facebook, sometimes you also want to post pictures on user wall. Once you acquire the user session, this posting image is pretty easy, but you must have requested the publish_actions permission when logging in the user for this to work.PHP
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if ($session){ //if we have the FB session
$image = "/home/images/image_name.jpg";
$post_data = array('source' => '@'.$image, 'message' => 'This is test Message');
$response = (new FacebookRequest( $session, 'POST', '/me/photos', $post_data ))->execute()->getGraphObject();
}Post link on user Wall
Posting link work similar way, publish_actions scope is required here too.PHP
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if ($session){ //if we have the FB session
$post_data = array( 'link' => 'www.example.com', 'message' => 'This is test Message' );
$response = (new FacebookRequest( $session, 'POST', '/me/feed', $post_data ))->execute()->getGraphObject();
}Check Granted Permission
Sometimes you want to check particular permission before performing a task. For example before posting an image you might want to check whether a user has granted “publish_action” permission, because without this permission your application will run into nasty error. So, in that case you can use something like this:PHP
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if ($session){ //if we have the FB session
$user_permissions = (new FacebookRequest($session, 'GET', '/me/permissions'))->execute()->getGraphObject(GraphUser::className())->asArray();
//check publish stream permission
$found_permission = false;
foreach($user_permissions as $key => $val){
if($val->permission == 'publish_actions'){
$found_permission = true;
}
}
if($found_permission){
//do your stuff
}
}
