<?php
$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
";
$header .= "Content-Type: application/x-www-form-urlencoded
";
$header .= "Content-Length: " . strlen($req) . "

";
$fp = fsockopen ('ssl://www.sandbox.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'];
$txn_id             = $_POST['txn_id'];
$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) {
$fh = fopen("test.txt","w");
fwrite($fh, $payer_email);
}else if (strcmp ($res, "INVALID") == 0) {
//Send Email To You
}
}

fclose ($fp);
}
?>

Writes to a text file, test.txt, instead of email for the purposes of testing.

Test PayPal ipn to file

file, text

PHP