Php function to Send Gcm more than 1000 users - php

Question

I have function code to send gcm, it works until token GCM ID have reached more than 1000 users it will not send.
this is my function code.
private static function send_message($title,$url){
global $wpdb;
$token = $wpdb->get_results( 'SELECT * FROM '.$wpdb->prefix.'devices', ARRAY_N );
foreach ($token as $key) {
$registrationIds[] = $key[1];
}
$msg = array(
'registrationIds' => $group,
'message' => $title,
'url' => $url,
'title' => 'This is a title. title',
);
$fields = array(
'registration_ids' => $registrationIds,
'data' => $msg
);
$headers = array(
'Authorization: key=' . FA_API,
'Content-Type: application/json'
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://fcm.googleapis.com/fcm/send');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
$result = curl_exec($ch);
curl_close($ch);
return $result;
}
Please help me how to send push notification more than 1000 users.

Answer 1

This parameter specifies a list of devices (registration tokens, or
IDs) receiving a multicast message. It must contain at least 1 and at
most 1000 registration tokens.
https://developers.google.com/cloud-messaging/http-server-ref#downstream-http-messages-json
GCM limit 1000 device each message.
So you have to split $registrationIds array into to smaller arrays. Then sends them away in a loop.