single-multiple-posting-managed-groups.php

<?php
session_start();

require_once __DIR__ . '/src/Facebook/autoload.php'; // download official fb sdk for php @ https://github.com/facebook/php-graph-sdk

$fb = new Facebook\Facebook([
  'app_id' => 'APP_ID',
  'app_secret' => 'APP_SECRET',
  'default_graph_version' => 'v2.12',
]);

$helper = $fb->getCanvasHelper();

$permissions = ['user_managed_groups', 'publish_actions']; // optionnal

try {
	if (isset($_SESSION['facebook_access_token'])) {
	$accessToken = $_SESSION['facebook_access_token'];
	} else {
  		$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;
 }

if (isset($accessToken)) {
	if (isset($_SESSION['facebook_access_token'])) {
		$fb->setDefaultAccessToken($_SESSION['facebook_access_token']);
	} else {
		$_SESSION['facebook_access_token'] = (string) $accessToken;

	  	// OAuth 2.0 client handler
		$oAuth2Client = $fb->getOAuth2Client();

		// Exchanges a short-lived access token for a long-lived one
		$longLivedAccessToken = $oAuth2Client->getLongLivedAccessToken($_SESSION['facebook_access_token']);

		$_SESSION['facebook_access_token'] = (string) $longLivedAccessToken;

		$fb->setDefaultAccessToken($_SESSION['facebook_access_token']);
	}

	// redirect user back to app when page receives $_GET['code'] variable
	if (isset($_GET['code'])) {
		echo "<script>window.top.location.href='https://apps.facebook.com/APP_NAMESPACE';</script>";
		exit;
	}
	
	// validating the access token
	try {
		$request = $fb->get('/me');
	} catch(Facebook\Exceptions\FacebookResponseException $e) {
		// When Graph returns an error
		if ($e->getCode() == 190) {
			unset($_SESSION['facebook_access_token']);
			$helper = $fb->getRedirectLoginHelper();
			$loginUrl = $helper->getLoginUrl('https://apps.facebook.com/APP_NAMESPACE/', $permissions);
			echo "<script>window.top.location.href='".$loginUrl."'</script>";
			exit;
		}
	} catch(Facebook\Exceptions\FacebookSDKException $e) {
		// When validation fails or other local issues
		echo 'Facebook SDK returned an error: ' . $e->getMessage();
		exit;
	}

	// get list of groups managed by user
	try {
		$requestGroups = $fb->get('/me/groups');
		$groups = $requestGroups->getGraphEdge()->asArray();
	} 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;
	}

	// post in single group managed by user
	foreach ($groups as $key) {
		if ($key['name'] == 'Funny Demons') {
			$groupId = $key['id'];
		}
	}

	try {
		$requestPost = $fb->post('/' . $groupId . '/feed', array('message' => 'this message field must come from user-end as Facebook strictly prohibits the pre-filled message field'));
		$post = $requestPost->getGraphNode()->asArray();
	} 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;
	}

	// get response of single posting
	print_r($post);

	// post in all groups managed by user
	foreach ($groups as $key) {
		try {
			$requestMultiPost = $fb->post('/' . $key['id'] . '/feed', array('message' => 'this message field must come from user-end as Facebook strictly prohibitsf the pre-filled message field'));
			$multiPost = $requestMultiPost->getGraphNode()->asArray();
		} 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;
		}
	}
	
	// get response for multiple posting
	print_r($multiPost);
  	// Now you can redirect to another page and use the access token from $_SESSION['facebook_access_token']
} else {
	$helper = $fb->getRedirectLoginHelper();
	$loginUrl = $helper->getLoginUrl('https://apps.facebook.com/APP_NAMESPACE/', $permissions);
	echo "<script>window.top.location.href='".$loginUrl."'</script>";
}