PHP Socket.io

<?php

namespace app;

ini_set('memory_limit', '40m');

use app\User;
use Ratchet\ConnectionInterface;
use Ratchet\MessageComponentInterface;

class Notification extends User implements MessageComponentInterface
{
    protected $clients;
    private $subscriptions;
    private $users;

    public function __construct()
    {
        $this->clients = new \SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn)
    {
        $this->clients->attach($conn);

        echo 'Connecting...';

        $queryString = $conn->httpRequest->getUri()->getQuery();
        $queryArray = explode('=', $queryString);

        $this->users[$queryArray[1]] = $conn;

        echo "New user connected! ({$queryArray[1]})";
    }

    public function onMessage(ConnectionInterface $from, $message)
    {
        $message = json_decode($message, true);

        echo "\n";
        echo "\n";
        echo "\n";
        echo print_r($message, true);



        $numRecv = count($this->users) - 1;
        // echo sprintf("Number of connected users: %d \n", $numRecv);

        $receiver = (new LoginToken)->getUserToken($message['receiver-id']);


        /* echo "\n";
        echo "\n";
        echo "Is receiver online: ";
        echo "Receiver: $receiver \n\n\n";
        print((int) array_key_exists($receiver, $this->users)); */

        // Create a new transaction
        $order = new Order;

        $customer = (new User)->getUserByToken($message['login-token'])['id'];

        $order->setOrderOption($message['order-option']);
        $order->setQuantity($message['quantity']);
        $order->setPrice($message['price']);
        $order->setDeliveryAddress($message['delivery-address']);
        $order->setPaymentOption($message['payment-option']);
        // $order->setCustomer($customer);

        // Save order to DB
        $order->save();

        if (array_key_exists($receiver, $this->users))
            // Send a notication to a logged in Admin
            $this->users[$receiver]->send($message);
    }

    public function onClose(ConnectionInterface $conn)
    {
        // The connection is closed, remove it, as we can no longer send it messages
        $this->clients->detach($conn);

        echo "Connection {$conn->resourceId} has disconnected\n";
    }

    public function onError(ConnectionInterface $conn, \Exception $e)
    {
        echo "An error has occurred: {$e->getMessage()}\n";

        $conn->close();
    }
}