How to build a mysql queuing system with count downs? - php

Question

I am working on a browser/mobile game and I am trying to build a system that automatically ends queued tasks after a certain time has passed. It's the basic research schema used in most games.
Research A costs $100 and will take 1 hour to complete. Do I have to check every second for tasks that are at or past their completion time and trigger an event to clear them and increment the level number? Is there a better way or more optimum way? This idea works by itself but what happens if you need to run 5 or 6 different queues in the game design? show I abstract them enough to get them all in one table?
I apologize if I seem a little vague or erratic with my questions. I am trying to figure out where to start with this concept.

Answer 1

I'm not very familiar with it, but I believe you could use websockets or NodeJS to create a callback event, you could then call that callback with a PHP socket server. This kind of
You can base yourself off this tutorial: http://www.sanwebe.com/2013/05/chat-using-websocket-php-socket
Steps
First, identify the message type using the websocket.onmessage callback, something similar to this should work:
websockets.onmessage = function(ev)
{
var msg = JSON.parse(ev.data); //Assuming you'll encode the message components in JSON with PHP
if ( msg.type == "research_end" )
{
FinishResearch(msg.content); //Assuming that the content element of the JSON array contains the ID of the research
}
}
Secondly, make the server send the actual message. To not make this too complicated or long I'll just pretend that sendMessage($msg, $client) is a function that sends a message to a client.
However, as explained in the tutorial, each client socket is stored in an array called $clients, you'll have to add some kind of identifier to each research so it's easy to know which research belongs to what client.
Now, here's an important part. On the server there will be a variable called $research which will be structured as such:
$research['peername'][0]['time'] = 60000
$research['peername'][0]['type'] = 20
You can add the research by sending an outgoing message to the websocket server by using this:
var array = {message: '20', type: 'research', time : '300000'}; //Create the request array
websocket.send(JSON.stringify(msg)); //Send it to the socket server as a json string, decode with json_decode once it arrives
Then, when it gets to the server and is identified as a research request, we call a callback called doResearch which takes two arguments
//loop through all connected sockets
foreach ($changed as $changed_socket) {
//check for any incomming data
while(socket_recv($changed_socket, $buf, 1024, 0) >= 1)
{
$received_text = unmask($buf); // Unmask data
$msg_array = json_decode($received_text); // Decode the JSON string we sent to the server
doResearch($msg_array, $changed_socket); // Let's say this function contains all the procedures to do the research
}
}
doResearch would be similar to this:
function doResearch($msg_array, $socket)
{
$name = socket_getpeername($socket, $addr);
$count = count($research[$name]);
$research[$name][$count]['time'] = $msg_array['time'];
$research[$name][$count]['type'] = $msg_array['type'];
}
And finally, you would have to add a conditional like this inside the main server loop:
foreach ( $research as $i )
{
foreach ( $i as $i2 )
{
if ( time() <= $i2['time'] )
{
$sql->query("INSERT INTO researches('peer', 'researchid') VALUES ('".$i."', '".$i2['type']."')");
sendMessage('Research type '.$i2['type'].' has finished.', $i2['socket']);
}
}
}
Then, that would check if a research has been finished and insert it into the database.
Hope this helps.