Using IPN on PayPal - php

Question

I've created a checkout system using PayPal. I'm using some code for the IPN that I got from GitHub, and I've added a piece of code to mark the item as sold in the inventory, which is stored in the website's MySQL database.
I have tested the code, and I have found that it carries out the CURL and a message is received at PayPal's end, but the code to update the database wasn't being executed. To test that the code to update the database worked, I moved it to before when the CURL is carried out. When I did this, the code ran, and the database was updated. So, there must be an issue that stops the code when the CURL is executed.
This is the entire code from the page that PayPal sends the IPN to.
<?php
// STEP 1: read POST data
// Reading POSTed data directly from $_POST causes serialization issues with array data in the POST.
// Instead, read raw POST data from the input stream.
$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
$keyval = explode ('=', $keyval);
if (count($keyval) == 2) {$myPost[$keyval[0]] = urldecode($keyval[1]);}
}
// read the IPN message sent from PayPal and prepend 'cmd=_notify-validate'
$req = 'cmd=_notify-validate';
if(function_exists('get_magic_quotes_gpc')) {
$get_magic_quotes_exists = true;
}
foreach ($myPost as $key => $value) {
if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
$value = urlencode(stripslashes($value));
} else {
$value = urlencode($value);
}
$req .= "&$key=$value";
}
// STEP 2: POST IPN data back to PayPal to validate
$ch = curl_init('https://www.paypal.com/cgi-bin/webscr');
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// In wamp-like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set
// the directory path of the certificate as shown below:
// curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
if(!($res = curl_exec($ch))) {
error_log("Got " . curl_error($ch) . " when processing IPN data");
curl_close($ch);
exit;
}
// STEP 3: Inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
// The IPN is verified, process it:
// check whether 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 the notification
// assign posted variables to local variables
$item_number = $_POST['item_number'];
$item_name = $_POST['item_name'];
$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 = $_POST['payer'];
include('sql.php');
mysqli_query($mysqli, $sql);
$sql = "UPDATE inventory SET sold='1' WHERE code='".$item_number."'";
if (mysqli_query($mysqli, $sql)) {
foreach($_POST as $key => $value) {
echo $key." = ". $value."<br>";
}
}else{
echo $mysqli->error;
}
mysqli_close($mysqli);
} else if (strcmp ($res, "INVALID") == 0) {
// IPN invalid, log for manual investigation
echo "The response from IPN was: <b>" .$res ."</b>";
}
curl_close($ch);
?>

Answer 1

I literally just did this two weeks ago. Such a pain in the butt. Here's what I used:
function connectAPI($data, $location){
$getData = array();
foreach($data as $key=>$value){
$getData[] = urlencode($key).'='.urlencode($value);
}
$location = $location . '?'.implode('&', $getData);
$ch = curl_init($location);
curl_setopt($ch,CURLOPT_USERAGENT,$_SERVER['HTTP_USER_AGENT']);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$return['status'] = $status;
$return['response'] = $response;
return $return;
}
$input = $_POST;
$headers = getallheaders();
$location = 'https://ipnpb.paypal.com/cgi-bin/webscr';
$response = array('cmd'=>'_notify-validate');
$jsondata = $response + $input;
$resend = connectAPI($jsondata, $location);
if($resend['response'] === 'VERIFIED'){
// --- Do what you need to do.
}
echo $resend['response'];