Paypal IPN callback stopped working in sandbox environment - paypal

Question

I'm having a problem with the paypal IPN callback. Paypal's IPN callback stopped working, in sandbox environment.
I've been testing my client's website, for the past weeks, and it has always been working correctly - The payment was made, and a callback IPN was sent back to the website, confirming the payment, and updating the website's database.
I haven´t change anything in my code, and it suddenly stopped working. The payment is still made and saved in the paypal account, but the IPN is always retrying... it doesn't complete.
Here's the code in use:
<?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
$ch = curl_init('https://www.sandbox.paypal.com/cgi-bin/webscr');
curl_setopt($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($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// In wamp-like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from [link removed] and set
// the directory path of the certificate as shown below:
// curl_setopt($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;
}
curl_close($ch);
……
?>
Firing some outputs to text files, I discovered that it passes the first Step and stops on the Second, before
if( !($res = curl_exec($ch)) ) {
I've already submitted three help requests to PayPal, but still didn't get an answer from them.

Answer 1

The cURL request initiates a HTTP POST back to PayPal in order to validate the IPN message. If it stops at this step, it means you do receive the IPN POST from PayPal, but you've got a problem connecting back to PayPal.
What does // error_log("Got " . curl_error($ch) . " when processing IPN data"); contain?
In order to resolve this, test the HTTPS connection from your server to the following addresses:
https://www.paypal.com/cgi-bin/webscr?cmd=_notify-validate
https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_notify-validate
For example, you can run cURL directly from your server (assuming you've got SSH access);
curl -v https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_notify-validate
This should return something similar to the following:
$ curl -v https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_notify-validate
* About to connect() to www.sandbox.paypal.com port 443 (#0)
* Trying 173.0.82.77...
* connected
* Connected to www.sandbox.paypal.com (173.0.82.77) port 443 (#0)
* successfully set certificate verify locations:
* CAfile: /usr/ssl/certs/ca-bundle.crt
CApath: none
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using AES256-SHA
* Server certificate:
* subject: 1.3.6.1.4.1.311.60.2.1.3=US; 1.3.6.1.4.1.311.60.2.1.2=Delaware; businessCategory=Private Organization; serialNumber=3014267; C=US; postalCode=95131-2021; ST=California; L=San Jose; street=2211 N 1st St; O=PayPal, Inc.; OU=PayPal Production; CN=www.sandbox.paypal.com
* start date: 2011-09-01 00:00:00 GMT
* expire date: 2013-09-30 23:59:59 GMT
* common name: www.sandbox.paypal.com (matched)
* issuer: C=US; O=VeriSign, Inc.; OU=VeriSign Trust Network; OU=Terms of use at https://www.verisign.com/rpa (c)06; CN=VeriSign Class 3 Extended Validation SSL CA
* SSL certificate verify ok.
> GET /cgi-bin/webscr?cmd=_notify-validate HTTP/1.1
> User-Agent: curl/7.28.1
> Host: www.sandbox.paypal.com
> Accept: */*
>
* HTTP 1.1 or later with persistent connection, pipelining supported
< HTTP/1.1 200 OK
< Date: Wed, 14 Aug 2013 20:15:53 GMT
< Server: Apache
< X-Frame-Options: SAMEORIGIN
< Set-Cookie: xxxxx
< X-Cnection: close
< Set-Cookie: xxxx domain=.paypal.com; path=/; Secure; HttpOnly
< Set-Cookie: Apache=10.72.128.11.1376511353229960; path=/; expires=Fri, 07-Aug-43 20:15:53 GMT
< Vary: Accept-Encoding
< Strict-Transport-Security: max-age=14400
< Transfer-Encoding: chunked
< Content-Type: text/html; charset=UTF-8
<
* Connection #0 to host www.sandbox.paypal.com left intact
**INVALID* Closing connection #0**
* SSLv3, TLS alert, Client hello (1):
If you receive a timeout or an SSL handshake error, you will need to investigate this separately.