Time/date difference with client and server? - php

Question

I'm sorry if this has been asked before or if I'm not able to explain in a great way. I've spent hours trying to wrap my head around the issue and I just can't seem to fix this issue. The code is working fine locally, but when I upload it to my server there seems to be some sort of issue with how the server handles/checks differences in time between server and client. Not sure exactly how or what to think. I'm also aware that I'm inserting data into pdo statements incorrectly, I don't care about that at the moment. I will tidy all this up at a later point.
The part of the application that I'm experiencing issues with is when it checks an active shipment (it's a sort of game). I want to compare the timestamp from the database with the current time to see if the time has passed. In the case that the arrival time is past, then I want to set the status of the shipment to 'delivered' as well as add the data to another table called 'storage'.
function check_active_shipment(){
$pdo = pdo();
$username = $_SESSION['username'];
$statement = $pdo->prepare("SELECT * FROM shipments WHERE username LIKE '$username' AND status LIKE 'active' LIMIT 1");
$statement->execute();
$rows = $statement->fetch();
$id = $rows['id'];
if($rows['type'] == "purchase"){
if(time() >= strtotime($rows['arrival'])){
$statement = $pdo->prepare("UPDATE shipments SET status='delivered' WHERE id LIKE '$id'");
$statement->execute();
$statement = $pdo->prepare("INSERT INTO storage (username, crate_type_id, quantity) VALUES (?, ?, ?)");
$statement->bindParam(1, $username);
$statement->bindParam(2, $rows['crate_type_id']);
$statement->bindParam(3, $rows['quantity']);
$statement->execute();
//header("location:index.php");
}
}
else if($rows['type'] == "sale"){
if(time() >= strtotime($rows['arrival'])){
$statement = $pdo->prepare("UPDATE shipments SET status='delivered' WHERE id LIKE ?");
$statement->bindParam(1, $id);
$statement->execute();
$statement = $pdo->prepare("SELECT cash FROM users WHERE username LIKE ?");
$statement->bindParam(1, $username);
$statement->execute();
$user = $statement->fetch();
$cash = $user['cash'] + $rows['value'];
$statement = $pdo->prepare("UPDATE users SET cash=?");
$statement->bindParam(1, $cash);
$statement->execute();
//header("location:index.php");
}
}
}
Let me know if there is any information I'm missing to share.

Answer 1

Would getting the time from the server, rather than using the time() function solve you problem.
Either do a separate query
SELECT NOW()
or add it to your existing query
SELECT *, NOW() as curtime FROM shipments WHERE .....

Answer 2

Have you tried using the DateTime Class? Perhaps it behaves much like you had expected... Here's a snippet on how to use it in your case:
<?php
// ...SOME CODE...
if($rows['type'] == "purchase"){
// TRY USING DateTime CLASS
$arrival = new DateTime($rows['arrival']);
$arrivalTS = $arrival->getTimestamp();
if(time() >= $arrivalTS){
// REST OF THE CODE...
}
}else if($rows['type'] == "sale") {
// TRY USING DateTime CLASS AGAIN
$arrival = new DateTime($rows['arrival']);
$arrivalTS = $arrival->getTimestamp();
if (time() >= $arrivalTS) {
// REST OF THE CODE...
}
}