我没有从stackoverflow上找到任何东西，所以我自己去尝试了，这就是我想出的，使用cookie来测试数据库是否已付款。
<?php
$payment_date = date("Y-m-01 00:00:00");
function endKey($array){
end($array);
return key($array);
}
$payments_due = array(
"2019-11-01 00:00:00",
"2019-12-01 00:00:00",
"2020-01-01 00:00:00",
"2020-02-01 00:00:00",
"2020-03-01 00:00:00",
"2020-04-01 00:00:00",
"2020-05-01 00:00:00",
"2020-06-01 00:00:00",
"2020-07-01 00:00:00",
"2020-08-01 00:00:00",
"2020-09-01 00:00:00",
"2020-10-01 00:00:00",
"2020-11-01 00:00:00",
"2020-12-01 00:00:00");
// If payment_date and not paid, unset cookie
for ($j = 0; $j < sizeof($payments_due); $j++) {
if ($j < endKey($payments_due)) {
$k = $j + 1;
}
// If payment_date is between current month and next month's payment
if ((strtotime($payment_date) >= strtotime($payments_due[$j])) && (strtotime($payment_date) < strtotime($payments_due[$k]))) {
// echo "Payment date: " . $payment_date . "<br />is >=<br />";
// echo "Payment due: " . $payments_due[$j] . "<br />is <<br />";
// echo "Payment due: " . $payments_due[$k] . "<br />";
// Check if payment due already in DB
$query = "SELECT *
FROM payments
WHERE farm_id = " . sanitise($_SESSION['farm_id']) . "
AND payment_due = '{$payment_date}'";
$data_set = mysqli_query($connection, $query);
confirm_query2($data_set, $query);
// If payment due not in DB, insert it
if (mysqli_num_rows($data_set) == 0) {
$query = "INSERT INTO payments (
farm_id, bill, payment_due
) VALUES (
" . sanitise($_SESSION['farm_id']) . ", {$monthly_bill}, '{$payment_date}'
)";
$data_set = mysqli_query($connection, $query);
confirm_query2($data_set, $query);
$first_name = $_SESSION['first_name'];
mail($email, "BuyRawMilk - Monthly Bill Due",
"Hello {$first_name},
<br /><br />Your monthly bill totalling " . sprintf("%0.2f", $monthly_bill) . " is due.
<br /><br />Please click here https://buyrawmilk.co.uk/orders.php to pay your bill.",
"[email protected]", "-f [email protected]");
}
// Get payments due
$query = "SELECT p.paid
FROM users u
LEFT JOIN settings s ON s.user_id = u.id
LEFT JOIN farms f ON s.farm_id = f.id
LEFT JOIN payments p ON s.farm_id = f.id
WHERE farmer = 1
AND payment_due = '{$payment_date}'
AND p.paid IS NULL
AND f.id = " . sanitise($_SESSION['farm_id']) . "
AND bill != 0
LIMIT 1";
$data_set = mysqli_query($connection, $query);
confirm_query2($data_set, $query);
$row = mysqli_fetch_array($data_set);
$paid = $row['paid'];
if(mysqli_num_rows($data_set) > 0) {
// If not paid bill
if ($paid == NULL) {
// Unset cookie
setcookie("payments", "payment_paid", 1);
// If paid bill
} else if ($paid != NULL) {
if (!isset($_COOKIE['payments'])) {
// Set cookie
setcookie("payments", "payment_paid", time() + (60*60*24)*3650);
}
}
} else {
// No payments due; unset cookie
setcookie("payments", "payment_paid", time() + (60*60*24)*3650);
}
}
}
?>
<?php if (!isset($_COOKIE['payments'])) { ?>
<br /><strong>Monthly bill due</strong>
<br />
<?php
$query = "SELECT p.bill, p.payment_due, p.paid
FROM users u
LEFT JOIN settings s ON s.user_id = u.id
LEFT JOIN farms f ON s.farm_id = f.id
LEFT JOIN payments p ON s.farm_id = f.id
WHERE farmer = 1
AND p.paid IS NULL
AND f.id = " . sanitise($_SESSION['farm_id']) . "
AND bill != 0";
$data_set = mysqli_query($connection, $query);
confirm_query2($data_set, $query);
?>
<table style='border:1px solid black;background-color:white;margin-top:10px;'>
<!-- *** Table: payments *** -->
<th style='text-align:center;background-color:silver;padding:5px;'>Payment due</th>
<th style='text-align:center;background-color:silver;padding:5px;'>Bill</th>
<th style='text-align:center;background-color:silver;padding:5px;'>Pay</th>
<?php while ($row = mysqli_fetch_array($data_set)) { ?>
<tr>
<!-- Payment due -->
<td style='padding:5px;background-color:#EEEEEE;'>
<?php $payment_due = $row['payment_due']; ?>
<?php if (date('Y-m-d', strtotime($payment_due)) == date('Y-m-d')) { echo "Today<br />"; } else { echo date('d/m/y', strtotime($payment_due)); } echo "</span>"; ?>
</td>
<!-- Bill -->
<td style='padding:5px;background-color:#EEEEEE;'>
<?php echo "£" . sprintf("%0.2f", $row['bill']); ?>
</td>
<!-- Pay -->
<td style='padding:5px;background-color:#EEEEEE;'>
<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_top">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="[email protected]">
<input type="hidden" name="lc" value="GB">
<input type="hidden" name="item_name" value="Payments">
<input type="hidden" name="amount" value="<?php echo $row['bill']; ?>">
<input type="hidden" name="currency_code" value="GBP">
<input type="hidden" name="button_subtype" value="services">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="rm" value="1">
<input type="hidden" name="return" value="../../../localhost/BuyRawMilk/check_paid.php">
<input type="hidden" name="cancel_return" value="http://buyrawmilk.co.uk/orders.php">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_buynowCC_LG.gif:NonHostedGuest">
<input type="image" src="https://www.paypalobjects.com/en_GB/i/btn/btn_paynow_SM.gif" border="0" name="submit" alt="PayPal – The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>
</td>
</tr>
<?php } ?>
<?php if(mysqli_num_rows($data_set) == 0) { ?>
<tr>
<td colspan="5" style='text-align:center;padding:5px;background-color:#EEEEEE;'>
No items to display.
</td>
</tr>
<?php } ?>
</table>
<?php } ?>