I remember playing with the IPN a while back, here is what I have:
subscribe.php
[PHP]
[/PHP]
That sends the user to the paypal payment page and you see the return field? That’s Paypal will send the user back to.
ipn.php
[PHP]
<?php
// tell PHP to log errors to ipn_errors.log in this directory
ini_set('log_errors', true);
ini_set('error_log', dirname(__FILE__).'/ipn_errors.log');
// intantiate the IPN listener
include('ipnlistener.php');
$listener = new IpnListener();
// tell the IPN listener to use the PayPal test sandbox
$listener->use_sandbox = true;
// try to process the IPN POST
try {
$listener->requirePostMethod();
$verified = $listener->processIpn();
} catch (Exception $e) {
error_log($e->getMessage());
exit(0);
}
// TODO: Handle IPN Response here
// ...
if ($verified) {
// TODO: Implement additional fraud checks and MySQL storage
mail('
[email protected]', 'Valid IPN', $listener->getTextReport());
//To test you can print_r($listener->getTextReport()) to find out what is returned, but I'm sure there's an auth code once you get this, you can store the auth code in your db against the users email address
} else {
// manually investigate the invalid IPN
mail('
[email protected]', 'Invalid IPN', $listener->getTextReport());
//With the above, this will alert you that the user has cancelled the subscription
}
// ...
?>
[/PHP]
ipnlistner.php
[PHP]
<?php
/**
* PayPal IPN Listener
*
* A class to listen for and handle Instant Payment Notifications (IPN) from
* the PayPal server.
*
* https://github.com/Quixotix/PHP-PayPal-IPN
*
* @package PHP-PayPal-IPN
* @author Micah Carrick
* @copyright (c) 2012 - Micah Carrick
* @version 2.1.0
*/
class IpnListener {
/**
* If true, the recommended cURL PHP library is used to send the post back
* to PayPal. If flase then fsockopen() is used. Default true.
*
* @var boolean
*/
public $use_curl = true;
/**
* If true, explicitly sets cURL to use SSL version 3. Use this if cURL
* is compiled with GnuTLS SSL.
*
* @var boolean
*/
public $force_ssl_v3 = true;
/**
* If true, cURL will use the CURLOPT_FOLLOWLOCATION to follow any
* "Location: ..." headers in the response.
*
* @var boolean
*/
public $follow_location = false;
/**
* If true, an SSL secure connection (port 443) is used for the post back
* as recommended by PayPal. If false, a standard HTTP (port 80) connection
* is used. Default true.
*
* @var boolean
*/
public $use_ssl = true;
/**
* If true, the paypal sandbox URI www.sandbox.paypal.com is used for the
* post back. If false, the live URI www.paypal.com is used. Default false.
*
* @var boolean
*/
public $use_sandbox = false;
/**
* The amount of time, in seconds, to wait for the PayPal server to respond
* before timing out. Default 30 seconds.
*
* @var int
*/
public $timeout = 30;
private $post_data = array();
private $post_uri = '';
private $response_status = '';
private $response = '';
const PAYPAL_HOST = 'www.paypal.com';
const SANDBOX_HOST = 'www.sandbox.paypal.com';
/**
* Post Back Using cURL
*
* Sends the post back to PayPal using the cURL library. Called by
* the processIpn() method if the use_curl property is true. Throws an
* exception if the post fails. Populates the response, response_status,
* and post_uri properties on success.
*
* @param string The post data as a URL encoded string
*/
protected function curlPost($encoded_data) {
if ($this->use_ssl) {
$uri = 'https://'.$this->getPaypalHost().'/cgi-bin/webscr';
$this->post_uri = $uri;
} else {
$uri = 'http://'.$this->getPaypalHost().'/cgi-bin/webscr';
$this->post_uri = $uri;
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_CAINFO,
dirname(__FILE__)."/cert/api_cert_chain.crt");
curl_setopt($ch, CURLOPT_URL, $uri);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $encoded_data);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, $this->follow_location);
curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);
if ($this->force_ssl_v3) {
curl_setopt($ch, CURLOPT_SSLVERSION, 3);
}
$this->response = curl_exec($ch);
$this->response_status = strval(curl_getinfo($ch, CURLINFO_HTTP_CODE));
if ($this->response === false || $this->response_status == '0') {
$errno = curl_errno($ch);
$errstr = curl_error($ch);
throw new Exception("cURL error: [$errno] $errstr");
}
}
/**
* Post Back Using fsockopen()
*
* Sends the post back to PayPal using the fsockopen() function. Called by
* the processIpn() method if the use_curl property is false. Throws an
* exception if the post fails. Populates the response, response_status,
* and post_uri properties on success.
*
* @param string The post data as a URL encoded string
*/
protected function fsockPost($encoded_data) {
if ($this->use_ssl) {
$uri = 'ssl://'.$this->getPaypalHost();
$port = '443';
$this->post_uri = $uri.'/cgi-bin/webscr';
} else {
$uri = $this->getPaypalHost(); // no "http://" in call to fsockopen()
$port = '80';
$this->post_uri = 'http://'.$uri.'/cgi-bin/webscr';
}
$fp = fsockopen($uri, $port, $errno, $errstr, $this->timeout);
if (!$fp) {
// fsockopen error
throw new Exception("fsockopen error: [$errno] $errstr");
}
$header = "POST /cgi-bin/webscr HTTP/1.1\r\n";
$header .= "Host: ".$this->getPaypalHost()."\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: ".strlen($encoded_data)."\r\n";
$header .= "Connection: Close\r\n\r\n";
fputs($fp, $header.$encoded_data."\r\n\r\n");
while(!feof($fp)) {
if (empty($this->response)) {
// extract HTTP status from first line
$this->response .= $status = fgets($fp, 1024);
$this->response_status = trim(substr($status, 9, 4));
} else {
$this->response .= fgets($fp, 1024);
}
}
fclose($fp);
}
private function getPaypalHost() {
if ($this->use_sandbox) return self::SANDBOX_HOST;
else return self::PAYPAL_HOST;
}
/**
* Get POST URI
*
* Returns the URI that was used to send the post back to PayPal. This can
* be useful for troubleshooting connection problems. The default URI
* would be "ssl://www.sandbox.paypal.com:443/cgi-bin/webscr"
*
* @return string
*/
public function getPostUri() {
return $this->post_uri;
}
/**
* Get Response
*
* Returns the entire response from PayPal as a string including all the
* HTTP headers.
*
* @return string
*/
public function getResponse() {
return $this->response;
}
/**
* Get Response Status
*
* Returns the HTTP response status code from PayPal. This should be "200"
* if the post back was successful.
*
* @return string
*/
public function getResponseStatus() {
return $this->response_status;
}
/**
* Get Text Report
*
* Returns a report of the IPN transaction in plain text format. This is
* useful in emails to order processors and system administrators. Override
* this method in your own class to customize the report.
*
* @return string
*/
public function getTextReport() {
$r = '';
// date and POST url
for ($i=0; $i<80; $i++) { $r .= '-'; }
$r .= "\n[".date('m/d/Y g:i A').'] - '.$this->getPostUri();
if ($this->use_curl) $r .= " (curl)\n";
else $r .= " (fsockopen)\n";
// HTTP Response
for ($i=0; $i<80; $i++) { $r .= '-'; }
$r .= "\n{$this->getResponse()}\n";
// POST vars
for ($i=0; $i<80; $i++) { $r .= '-'; }
$r .= "\n";
foreach ($this->post_data as $key => $value) {
$r .= str_pad($key, 25)."$value\n";
}
$r .= "\n\n";
return $r;
}
/**
* Process IPN
*
* Handles the IPN post back to PayPal and parsing the response. Call this
* method from your IPN listener script. Returns true if the response came
* back as "VERIFIED", false if the response came back "INVALID", and
* throws an exception if there is an error.
*
* @param array
*
* @return boolean
*/
public function processIpn($post_data=null) {
$encoded_data = 'cmd=_notify-validate';
if ($post_data === null) {
// use raw POST data
if (!empty($_POST)) {
$this->post_data = $_POST;
$encoded_data .= '&'.file_get_contents('php://input');
} else {
throw new Exception("No POST data found.");
}
} else {
// use provided data array
$this->post_data = $post_data;
foreach ($this->post_data as $key => $value) {
$encoded_data .= "&$key=".urlencode($value);
}
}
if ($this->use_curl) $this->curlPost($encoded_data);
else $this->fsockPost($encoded_data);
if (strpos($this->response_status, '200') === false) {
throw new Exception("Invalid response status: ".$this->response_status);
}
if (strpos($this->response, "VERIFIED") !== false) {
return true;
} elseif (strpos($this->response, "INVALID") !== false) {
return false;
} else {
throw new Exception("Unexpected response from PayPal.");
}
}
/**
* Require Post Method
*
* Throws an exception and sets a HTTP 405 response header if the request
* method was not POST.
*/
public function requirePostMethod() {
// require POST requests
if ($_SERVER['REQUEST_METHOD'] && $_SERVER['REQUEST_METHOD'] != 'POST') {
header('Allow: POST', true, 405);
throw new Exception("Invalid HTTP request method.");
}
}
}
[/PHP]
As I said it was a while back and I didn't get around to finishing it as it was no longer a requirement. I stopped working on it just before I hooked it up to a db, the ipn.php under if ($verified) is where you validate/remove subscriptions.
The full GIT is here: https://github.com/Quixotix/PHP-PayPal-IPN
