Gazelle/sections/donate/ipn.php

<?php

// Paypal hits this page once a donation has gone through.
// This may appear to be light on the input validation, but the vast majority of that is handled through paypal confirmation
// $_POST['txn_id'] centains the unique identifier if anyone ever needs it
if (!is_number($_POST['custom'])) {
    error(); // Seems too stupid a mistake to bother banning
}

$ENV = ENV::go();

// Create request to return to paypal
$Request = 'cmd=_notify-validate';
foreach ($_POST as $Key => $Value) {
    $Value = urlencode(stripslashes($Value));
    $Request .= "&$Key=$Value";
}

// Headers
$Headers = "POST /cgi-bin/webscr HTTP/1.1\r\n";
$Headers .= "Host: www.paypal.com\r\n";
$Headers .= "Content-Type: application/x-www-form-urlencoded\r\n";
$Headers .= "Content-Length: ".strlen($Request)."\r\n";
$Headers .= "Connection: close\r\n\r\n";

// Socket
$Socket = fsockopen('www.paypal.com', 80, $errno, $errstr, 30);

// Send and process reply
fwrite($Socket, $Headers.$Request);
$Result = '';

while (!feof($Socket)) {
    $Result .= fgets($Socket, 1024);
}

if (strpos($Result, 'VERIFIED') !== false || check_perms('site_debug')) {
    if ($_POST['mc_gross'] >= PAYPAL_MINIMUM) {
        if ($_POST['mc_currency'] == PAYPAL_CURRENCY) {
            if ($_POST['business'] == PAYPAL_ADDRESS) {
                if (($_POST['payment_status'] == 'Completed') || ($_POST['payment_status'] == 'Pending')) {
                    $DB->query('
                      SELECT Donor
                      FROM users_info
                      WHERE UserID = \''.$_POST['custom'].'\'');

                    list($Donor) = $DB->next_record();
                    if ($Donor == 0) {
                        //First time donor
                        $DB->query('
                          UPDATE users_main
                          SET Invites = Invites + \''.DONOR_INVITES.'\'
                          WHERE ID = \''.$_POST['custom'].'\'');

                        $DB->query('
                          UPDATE users_info
                          SET Donor = \'1\'
                          WHERE UserID = \''.$_POST['custom'].'\'');

                        $DB->query('
                          SELECT Invites
                          FROM users_main
                          WHERE ID = \''.$_POST['custom'].'\'');

                        list($Invites) = $DB->next_record();
                        $Cache->begin_transaction('user_info_'.$_POST['custom']);
                        $Cache->update_row(false, array('Donor' => 1));
                        $Cache->commit_transaction(0);
                        $Cache->begin_transaction('user_info_heavy_'.$_POST['custom']);
                        $Cache->update_row(false, array('Invites' => $Invites));
                        $Cache->commit_transaction(0);
                        Misc::send_pm($_POST['custom'], 0, 'Thank you for your donation', 'Your donation from '.$_POST['payer_email'].' of '.$_POST['mc_gross'].' '.PAYPAL_CURRENCY.' has been successfully processed. Because this is your first time donating, you have now been awarded Donor status as represented by the <3 found on your profile and next to your username where it appears. This has entitled you to a additional site features which you can now explore, and has granted you '.DONOR_INVITES." invitations to share with others. Thank you for supporting $ENV->SITE_NAME.");
                    } else {
                        // Repeat donor
                        Misc::send_pm($_POST['custom'], 0, 'Thank you for your donation', 'Your donation from '.$_POST['payer_email'].' of '.$_POST['mc_gross'].' '.PAYPAL_CURRENCY.' has been successfully processed. Your continued support is highly appreciated and helps to make this place possible.');
                    }
                }
            }
        }
    } else {
        if ($_POST['mc_gross'] > 0) {
            // Donation less than minimum
            Misc::send_pm($_POST['custom'], 0, 'Thank you for your donation', 'Your donation from '.$_POST['payer_email'].' of '.$_POST['mc_gross'].' '.PAYPAL_CURRENCY.' has been successfully processed. Unfortunately however this donation was less than the specified minimum donation of '.PAYPAL_MINIMUM.' '.PAYPAL_CURRENCY.' and while we are grateful, no special privileges have been awarded to you.');
        } else {
            // Failed pending donation
            $Message = "User ".site_url()."user.php?id=".$_POST['custom']." had donation of $TotalDonated ".PAYPAL_CURRENCY." at $DonationTime UTC from ".$_POST['payer_email'].' returned.';
            $DB->query('
              SELECT SUM(Amount), MIN(Time)
              FROM donations
              WHERE UserID = \''.$_POST['custom'].'\';');

            list($TotalDonated, $DonationTime) = $DB->next_record();
            if ($TotalDonated + $_POST['mc_gross'] == 0) {
                $DB->query("
                  SELECT Invites
                  FROM users_main
                  WHERE ID = '".$_POST['custom']."'");

                list($Invites) = $DB->next_record();
                if (($Invites - DONOR_INVITES) >= 0) {
                    $NewInvites = $Invites - DONOR_INVITES;
                } else {
                    $NewInvites = 0;
                    $Message .= ' They had already used at least one of their donation gained invites.';
                }

                $DB->query("
                  UPDATE users_main
                  SET Invites = $NewInvites
                  WHERE ID = '".$_POST['custom']."'");

                $DB->query('
                  UPDATE users_info
                  SET Donor = \'0\'
                  WHERE UserID = \''.$_POST['custom'].'\'');

                $Cache->begin_transaction('user_info_'.$_POST['custom']);
                $Cache->update_row(false, array('Donor' => 0));
                $Cache->commit_transaction(0);
                $Cache->begin_transaction('user_info_heavy_'.$_POST['custom']);
                $Cache->update_row(false, array('Invites' => $Invites));
                $Cache->commit_transaction(0);
                Misc::send_pm($_POST['custom'], 0, 'Notice of donation failure', 'PapPal has just notified us that the donation you sent from '.$_POST['payer_email'].' of '.$TotalDonated.' '.PAYPAL_CURRENCY.' at '.$DonationTime.' UTC has been revoked. Because of this your special privileges have been revoked, and your invites removed.');
                send_irc(STAFF_CHAN, $Message);
            }
        }
    }

    $DB->query("
      UPDATE users_info
      SET AdminComment = CONCAT('".sqltime()." - User donated ".db_string($_POST['mc_gross'])." ".db_string(PAYPAL_CURRENCY)." from ".db_string($_POST['payer_email']).".\n',AdminComment)
      WHERE UserID = '".$_POST['custom']."'");

    $DB->query("
      INSERT INTO donations
        (UserID, Amount, Email, Time)
      VALUES
        ('".$_POST['custom']."', '".db_string($_POST['mc_gross'])."', '".db_string($_POST['payer_email'])."', NOW())");
} else {
    $DB->query("
      INSERT INTO ip_bans
        (FromIP, ToIP, Reason)
      VALUES
        ('".Tools::ip_to_unsigned($_SERVER['REMOTE_ADDR'])."', '".ip2long($_SERVER['REMOTE_ADDR'])."', 'Attempted to exploit donation system.')");
}

fclose($Socket);
if (check_perms('site_debug')) {
    include SERVER_ROOT.'/sections/donate/donate.php';
}
$Cache->cache_value('debug_donate', array($Result, $_POST), 0);