Starting with version 2.0, this SDK is PHP7 only! The SDK is considered stable, but will stay in beta until the documentation at http://firebase-php.readthedocs.io has been finished.
Quickstart
Create a service account as described in the Firebase Docs and download the service account JSON file, or retrieve a database secret from your Firebase application's project settings page.
$firebase = Firebase::fromServiceAccount(__DIR__.'/google-service-account.json');
// or
$firebase = Firebase::fromDatabaseUriAndSecret(
'https://<project>.firebaseio.com',
'<database secret>'
);
$db = $firebase->getDatabase();
$fullTree = $db
->getReference('/')
->orderByKey(SORT_DESC)
->getValue(); // Shortcut for ->getSnapshot()->getValue()
print_r($fullTree);