How to check something every 1 minute, and then send it to client?

Question

My problem is that I don't know how to check something without the need to interact with the client. I want to check every minute if its time for monster to respawn (by taking data from database), if it is - I want to send some msg to clients. I can send something to client, but how to execute specific code every minute? Currently my server side looks like this:

<?php
set_time_limit(0);

use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;
require_once '../vendor/autoload.php';

class Chat implements MessageComponentInterface {
    protected $clients;
    protected $users;

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






    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
         $this->users[$conn->resourceId] = $conn;



    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
         unset($this->users[$conn->resourceId]);
    }



    public function onMessage(ConnectionInterface $from,  $data) {
        $from_id = $from->resourceId;
        $data = json_decode($data);
        $type = $data->type;
        switch ($type) {
            case 'test':
                $user_id = $data->user_id;
                $chat_msg = $data->chat_msg;
                $response_from = "<span style='color:#999'><b>".$user_id.":</b> ".$chat_msg."</span><br><br>";
                $response_to = "<b>".$user_id."</b>: ".$chat_msg."<br><br>";
                // Output
                $from->send(json_encode(array("type"=>$type,"msg"=>$response_from)));
                foreach($this->clients as $client)
                {
                    if($from!=$client)
                    {
                        $client->send(json_encode(array("type"=>$type,"msg"=>$response_to)));
                    }
                }
                break;
            case 'chat':
                $user_id = $data->user_id;
                $chat_msg = $data->chat_msg;
                $response_from = "<span style='color:#999'><b>".$user_id.":</b> ".$chat_msg."</span><br><br>";
                $response_to = "<b>".$user_id."</b>: ".$chat_msg."<br><br>";
                // Output
                $from->send(json_encode(array("type"=>$type,"msg"=>$response_from)));
                foreach($this->clients as $client)
                {
                    if($from!=$client)
                    {
                        $client->send(json_encode(array("type"=>$type,"msg"=>$response_to)));
                    } 
                }
                break;  
        }
    }

    public function onError(ConnectionInterface $conn, \Exception $e) {
        $conn->close();
    }
}





$server = IoServer::factory(
    new HttpServer(new WsServer(new Chat())),
    8080
);
$server->run();
?>

Answer 1

One solution:

Write a unix cron script or windows scheduled task to run the php code every minute.

Answer 2

You need to have an open connections with clients, to send them any data. There is two ways to do it:

1. Every minute request data from client, const- with 1000 clients you will get 1000 requests per minute

2. Use websocket. For example use library https://socket.io/ , very simple and easy to start. Cons you need to write this part of site on nodejs.