PHP - PayPal Integration, failed running my custom transaction function after payment accepted - php

Question

I have tried using a tutorial script for PayPal payment in the past and it worked. Now it doesn't. The script is simple, all I need is this one page for processing payment:
<?php
session_start();
include ('mydbconfig.php');
// payPal settings
$paypal_email = 'seller#yahoo.com';
$return_url = 'https://www.mytestsite.com/paypal-thanks.php';
$cancel_url = 'https://www.mytestsite.com/paypal-cancel.php';
$notify_url = 'https://www.mytestsite.com/paypal-notify.php';
$item_name = $_POST['item_name'];
$item_amount = $_POST['item_amount']; //price
// check if paypal request or response
if (!isset($_POST["txn_id"]) && !isset($_POST["txn_type"])){
// firstly append paypal account to querystring
$querystring .= "?business=".urlencode($paypal_email)."&";
// append amount& currency (£) to quersytring so it cannot be edited in html
//the item name and amount can be brought in dynamically by querying the $_POST['item_number'] variable.
$querystring .= "item_name=".urlencode($item_name)."&";
$querystring .= "amount=".urlencode($item_amount)."&";
//loop for posted values and append to querystring
foreach($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$querystring .= "$key=$value&";
}
// Append paypal return addresses
$querystring .= "return=".urlencode(stripslashes($return_url))."&";
$querystring .= "cancel_return=".urlencode(stripslashes($cancel_url))."&";
$querystring .= "notify_url=".urlencode($notify_url);
// Append querystring with custom field
//$querystring .= "&custom=".USERID;
// Redirect to paypal IPN
header('location:https://www.paypal.com/cgi-bin/webscr'.$querystring);
exit();
} else { // response from Paypal
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$value = preg_replace('/(.*[^%^0^D])(%0A)(.*)/i','${1}%0D%0A${3}',$value);// IPN fix
$req .= "&$key=$value";
}
// assign posted variables to local variables
$data['item_name'] = $_POST['item_name'];
$data['item_number'] = $_POST['item_number'];
$data['payment_status'] = $_POST['payment_status'];
$data['payment_amount'] = $_POST['mc_gross'];
$data['payment_currency'] = $_POST['mc_currency'];
$data['txn_id'] = $_POST['txn_id'];
$data['receiver_email'] = $_POST['receiver_email'];
$data['payer_email'] = $_POST['payer_email'];
$data['custom'] = $_POST['custom'];
// 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.sandbox.paypal.com', 443, $errno, $errstr, 30);
if (!$fp) {
// HTTP ERROR
header('location: https://www.mytestsite.com/paypal-error.php?tr='.$data['txn_id'].'&in='.$data['item_name'].'&pe='.$data['payer_email'].'&pa='.$data['payment_amount'].'&ps='.$data['payment_status']);
} else {
fputs ($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "VERIFIED") == 0) {
//payment accepted, insert transaction to my database
//function to insert transaction here
} else if (strcmp ($res, "INVALID") == 0) {
//something to do if failed
}
}
fclose ($fp);
}
}
?>
After the process is completed, I checked and the payment is paid successfully, but my function or anything I wrote in //function to insert transaction here won't be executed. In the end I'm forced to do the function on paypal-thanks.php page. Is there something's wrong in the script?
Is this script can be used to send more than one item purchasing? My cart is my own custom made and I only want to send Item name, number, and price detail, and total price to PayPal order summary.
I checked the other PayPal integration questions here, and most of them direct me to PayPal tutorial, documentation, or integration wizard which're confusing. I use this simple script before because I can't understand PayPal documentation (and the sample code, it didn't even let me know where to start) :(
And lastly my ultimate question, is this script is the correct and secure way to do a payment transaction?

Answer 1

use this
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
instead of
$fp = fsockopen ('ssl://www.sandbox.paypal.com', 443, $errno, $errstr, 30);
i think it is better to use CURL instead of socket