iOS Push Notifications using Apple Push notification service

public function pushNotification($deviceToken, $message)
    {
    
        $passphrase = "bfl001";

        // Put your alert message here:
        // $message = 'My first push notification';

        $ctx = stream_context_create();
        // get your .pem file from apple itunes related to your project
        stream_context_set_option($ctx, 'ssl', 'local_cert', $this->rootPath.'/pushcert.pem');
        stream_context_set_option($ctx, 'ssl', 'passphrase', $passphrase);

        // Open a connection to the APNS server
        //$pushGateway = 'ssl://gateway.sandbox.push.apple.com:2195';
        $pushGateway = 'ssl://gateway.push.apple.com:2195';
        $fp = stream_socket_client($pushGateway, $err, $errstr, 60, STREAM_CLIENT_CONNECT | STREAM_CLIENT_PERSISTENT, $ctx);
        if (!$fp) {
            exit("Failed to connect: $err $errstr" . PHP_EOL);
        }

        //echo 'Connected to APNS' . PHP_EOL;
        // Create the payload body
        $body['aps'] = array(
          'alert' => $message,
          'sound' => 'notify.m4a'
        );

        // Encode the payload as JSON
        $payload = json_encode($body);

        // Build the binary notification
        $msg = chr(0) . pack('n', 32) . pack('H*', $deviceToken) . pack('n', strlen($payload)) . $payload;

        // Send it to the server
        $result = fwrite($fp, $msg, strlen($msg));

        // if (!$result) {
        //     echo 'Message not delivered' . PHP_EOL;
        // } else {
        //     echo 'Message successfully delivered' . PHP_EOL;
        // }
        // Close the connection to the server
        PHP_EOL;
        fclose($fp);
    }