paypal update db Help Pls

This may be a silly question but am stuck as one can be, have read a few forums and am getting no where.
Have added a paypal button for subscription, and want it to update the user db (groupID) when successfull, anyone have some script that can help with this please.
Or maybe another link which makes this a little more clear.
Have tried the net tuts guide and a few others so far.

Thanks in advance.

have enabled ipn on paypal, copied ipn script and added the following:


<?php
mysql_connect("localhost", "root", "root") or die(mysql_error());
mysql_select_db("users") or die(mysql_error());

// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';

foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$req .= "&$key=$value";
}

// post back to PayPal system to validate
$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);

// assign posted variables to local variables
$item_name = $_POST['item_name'];
$item_number = $_POST['item_number'];
$payment_status = $_POST['payment_status'];
$payment_amount = $_POST['mc_gross'];
$payment_currency = $_POST['mc_currency'];
$receiver_email = $_POST['receiver_email'];
$payer_email = $_POST['payer_email'];

if (!$fp) {
// HTTP ERROR
} else {
fputs ($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "VERIFIED") == 0) {

// check the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your Primary PayPal email
// check that payment_amount/payment_currency are correct
// process payment
}
else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
}
}
fclose ($fp);
}
?>

Got this far, just not far enough.......

the email address for the customer is coming through in a form element payer_email

$payer_email = $_POST['payer_email'];


you can add an update record behavior to update the users table, set the key column to the email column and use the following code for the value:

<?php echo((isset($_POST["payer_email"]))?$_POST["payer_email"]:"") ?>

Thanks for replying Jason
Like I said am a bit lost, actualy feel realy stupid here.....

so that I get this right...

Have edited the ipn form to the following:

<?php
mysql_connect("localhost", "user", "password") or die(mysql_error());
mysql_select_db("users") or die(mysql_error());

$req = 'cmd=_notify-validate';

foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$req .= "&$key=$value";
}

$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);

// assign posted variables to local variables
$payer_email = $_POST['payer_email'];

if (!$fp) {
// HTTP ERROR
} else {
fputs ($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "VERIFIED") == 0) {

mysql_query("UPDATE users SET groupID = '2' WHERE $_SESSION = ['SecurityAssist_UserID']");

// process payment
}
else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
}
}
fclose ($fp);
}
?>

Am guessing this is right for the insert, but then i get lost when "set the key column to the email column " and then use the code you included.....
Maybe its late and my brain is fried already, but still what's the change of finishing it for us so i can get this done, be super grateful am sure its a quick fix for urself also am also sure will understand it alot better if actually complete.
Thanks again

your update code is not correct:

mysql_query("UPDATE users SET groupID = '2' WHERE $_SESSION = ['SecurityAssist_UserID']");


you need to either update on the update based on the UserID column and the value in the SecurityAssist_UserID session:


mysql_query("UPDATE users SET groupID = '2' WHERE UserID = $_SESSION['SecurityAssist_UserID']");


or the email column being equal to the $payer_email value, assuming the name of the email column is UserEmail::


mysql_query("UPDATE users SET groupID = '2' WHERE UserEmail = '$payer_email'");

Thanks Jason, thats a lot clearer now!