Facebook API - Post as page in community groups - php

Question

With the new feature of connecting pages with groups (https://grytics.com/blog/link-facebook-groups-pages/) I tought, that it would be possible to post as page on group feed via Graph API. All my tries ended up with errors saying:
there´s no Edge/Node 'groups' on page
require_once "./vendor/autoload.php";
use Facebook\Facebook;
use Facebook\Exceptions\FacebookResponseException;
use Facebook\Exceptions\FacebookSDKException;
use Facebook\Authentication\OAuth2Client;
use Facebook\Authentication\AccessToken;
use Facebook\Helpers\FacebookRedirectLoginHelper;
$fb = new Facebook([
'app_id' => '123456',
'app_secret' => 'abcde',
'default_graph_version' => 'v2.10',
//'default_access_token' => PAGE_TOKEN, // optional
]);
$helper = $fb->getCanvasHelper();
$permissions = ['user_managed_groups', 'publish_actions', 'manage_pages', 'publish_pages'];
$tokenFileName = "./fb-token.txt";
$date = new DateTime();
$cityToPost = 'Berlin';
$autopostGroups = array();
$message = array(
'message' => 'TEST Post: '.$date->getTimestamp(),
'link' => 'https://domain.de'
);
try {
// Refresh longlicedaccesstoken with new one
if (file_exists($tokenFileName)) {
$token = file_get_contents($tokenFileName);
$lastTokenRefresh = time() - filemtime($tokenFileName);
if ($lastTokenRefresh > 60 * 60 * 24 * 7)
{
$oAuth2Client = $fb->getOAuth2Client();
$newToken = $oAuth2Client->getAccessTokenFromCode(
$oAuth2Client->getCodeFromLongLivedAccessToken(
$token
)
);
file_put_contents($tokenFileName, (string) $newToken);
$accessToken = (string) $newToken;
}else{
$accessToken = (string) $token;
}
} else {
$accessToken = $helper->getAccessToken();
}
} catch(FacebookResponseException $e) {
// When Graph returns an error
echo 'Graph returned an error: ' . $e->getMessage();
unlink($tokenFileName);
exit;
} catch(FacebookSDKException $e) {
// When validation fails or other local issues
echo 'Facebook SDK returned an error: ' . $e->getMessage();
unlink($tokenFileName);
exit;
}
if (isset($accessToken)) {
if (file_exists($tokenFileName)) {
$fb->setDefaultAccessToken(file_get_contents($tokenFileName));
} else {
// OAuth 2.0 client handler
$oAuth2Client = $fb->getOAuth2Client();
// Exchanges a short-lived access token for a long-lived one
$longLivedAccessToken = $oAuth2Client->getLongLivedAccessToken((string) $accessToken);
file_put_contents($tokenFileName, (string) $longLivedAccessToken);
$fb->setDefaultAccessToken($longLivedAccessToken);
}
// 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/xyz/';</script>";
exit;
}
// validating the access token
try {
$request = $fb->get('/me');
} catch(FacebookResponseException $e) {
// When Graph returns an error
if ($e->getCode() == 190) {
unlink($tokenFileName);
//unset($_SESSION['facebook_access_token']);
$helper = $fb->getRedirectLoginHelper();
$loginUrl = $helper->getLoginUrl('https://apps.facebook.com/xyz/', $permissions);
echo "<script>window.top.location.href='".$loginUrl."'</script>";
exit;
}
} catch(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(FacebookResponseException $e) {
// When Graph returns an error
echo 'Graph returned an error: ' . $e->getMessage();
exit;
} catch(FacebookSDKException $e) {
// When validation fails or other local issues
echo 'Facebook SDK returned an error: ' . $e->getMessage();
exit;
}
foreach ($groups as $group) {
if(strpos($group['name'], 'VENDOR') !== false && strpos($group['name'], $cityToPost) !== false){
array_push($autopostGroups,$group['id']); //Only for debugging
try {
$requestPost = $fb->post('/'.$group['id'].'/feed', $message);
$post = $requestPost->getGraphNode()->asArray();
var_dump($post);
} catch(FacebookResponseException $e) {
// When Graph returns an error
echo 'Graph returned an error: ' . $e->getMessage();
exit;
} catch(FacebookSDKException $e) {
// When validation fails or other local issues
echo 'Facebook SDK returned an error: ' . $e->getMessage();
exit;
}
}
}
// Now you can redirect to another page and use the access token from $tokenFileName
} else {
$helper = $fb->getRedirectLoginHelper();
$loginUrl = $helper->getLoginUrl('https://apps.facebook.com/xyz/', $permissions);
echo "<script>window.top.location.href='".$loginUrl."'</script>";
}
I am new to the fb api, and I am not a english native speaker, so maybe someone is able to clearify that situation?
Thank you!
[EDIT 1]
Added code. Hint: When I change PAGE_TOKEN to USER_TOKEN it works.
[EDIT 2]
Full Code added.
I found a user comment in the FB Group Facebook Developer Community from August:
And no, there is no build-in way to have page posts show up in a group
automatically.