Re: PayPal buttons: how do I protect sellers' sales?
Posted: Thu Nov 21, 2013 3:05 am
Thanks.
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Code: Select all
<?php
// CONFIG: Enable debug mode. This means we'll log requests into 'ipn.log' in the same directory.
// Especially useful if you encounter network errors or other intermittent problems with IPN (validation).
// Set this to 0 once you go live or don't require logging.
define("DEBUG", 1);
// Set to 0 once you're ready to go live
define("USE_SANDBOX", 1);
define("LOG_FILE", "./ipn.log");
// Read POST data
// reading posted data directly from $_POST causes serialization
// issues with array data in POST. Reading raw POST data from input stream instead.
$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 post from PayPal system and add 'cmd'
$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";
}
// Post IPN data back to PayPal to validate the IPN data is genuine
// Without this step anyone can fake IPN data
if(USE_SANDBOX == true) {
$paypal_url = "https://www.sandbox.paypal.com/cgi-bin/webscr";
} else {
$paypal_url = "https://www.paypal.com/cgi-bin/webscr";
}
$ch = curl_init($paypal_url);
if ($ch == FALSE) {
return FALSE;
}
curl_setopt($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);
if(DEBUG == true) {
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLINFO_HEADER_OUT, 1);
}
// CONFIG: Optional proxy configuration
//curl_setopt($ch, CURLOPT_PROXY, $proxy);
//curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
// Set TCP timeout to 30 seconds
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// CONFIG: Please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path
// of the certificate as shown below. Ensure the file is readable by the webserver.
// This is mandatory for some environments.
//$cert = __DIR__ . "./cacert.pem";
//curl_setopt($ch, CURLOPT_CAINFO, $cert);
$res = curl_exec($ch);
if (curl_errno($ch) != 0) // cURL error
{
if(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Can't connect to PayPal to validate IPN message: " . curl_error($ch) . PHP_EOL, 3, LOG_FILE);
}
curl_close($ch);
exit;
} else {
// Log the entire HTTP response if debug is switched on.
if(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "HTTP request of validation request:". curl_getinfo($ch, CURLINFO_HEADER_OUT) ." for IPN payload: $req" . PHP_EOL, 3, LOG_FILE);
error_log(date('[Y-m-d H:i e] '). "HTTP response of validation request: $res" . PHP_EOL, 3, LOG_FILE);
// Split response headers and payload
list($headers, $res) = explode("\r\n\r\n", $res, 2);
}
curl_close($ch);
}
// Inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your PayPal email
// check that payment_amount/payment_currency are correct
// process payment and mark item as paid.
// assign posted variables to local variables
//$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(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, LOG_FILE);
}
} else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
// Add business logic here which deals with invalid IPN messages
if(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Invalid IPN: $req" . PHP_EOL, 3, LOG_FILE);
}
}
?>Code: Select all
//$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 = $_POST['payer_email'];Code: Select all
// query db
if ($mc_gross == $row->price) { // update database to mark it as sold }Code: Select all
if(DEBUG == true) {
error_log('POST ARRAY CONTAINS:\r\n'.print_r($_POST,true), LOG_FILE);
}Code: Select all
if (strcmp ($res, "VERIFIED") == 0) {
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your PayPal email
// check that payment_amount/payment_currency are correct
// process payment and mark item as paid.
// 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(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, LOG_FILE);
}
} else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
// Add business logic here which deals with invalid IPN messages
if(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Invalid IPN: $req" . PHP_EOL, 3, LOG_FILE);
}Code: Select all
if (strcmp ($res, "VERIFIED") == 0) {
// 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']; //sometimes users use more than one email address (one for paypal and one for your site...use the 'custom' variable to track who they really are
$payer_custom= $_POST['custom']; // I added this so you can verify which user really made the purchase
// now that you have the data, check it against your database
// I suggest you look at all the $_POST data and log some of it to a table in your database to track the history
// Now you still need to do all the things the code comments helpfully tell you to do:
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your PayPal email
// check that payment_amount/payment_currency are correct
// process payment and mark item as paid.
if(DEBUG == true) {
error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, LOG_FILE);
}
}Code: Select all
<form action='https://www.sandbox.paypal.com/cgi-bin/webscr' method='post'>
<input type='hidden' name='business' value='$row->selleremail' />
// this is what does the processing after it's been finalised and updates my DB.
<input type='hidden' name='notify_url' value='http://YOURDOMAIN/paypal_ipn/process.php' />
<input type='hidden' name='currency_code' value='USD' />
<input type='hidden' name='lc' value='US' />
<input type='hidden' name='item_name' value='$row->title' />
<input type='hidden' name='amount' value='$15.00' />
<input type='hidden' name='sandbox' value='1' />
<input type='hidden' name='type' value='paynow' />
<input type='hidden' name='class' value='signup' />
<input type='hidden' name='custom' value='64b1add1e6349e3a2900fd4a9cf90e1f9e9090c54a983fdd56a3978812e66115' />
// what is difference between this and notify_url?
<input type='hidden' name='return_url' value='/Purchases' />
// we don't use this, but perhaps it's just the $row->id of the product in our database?
<input type='hidden' name='item_number' value='24adf829-15e6-11e3-b5bd-e0cb4e1c48db' />
<input type='hidden' name='cmd' value='_xclick' />
<input type="submit" value="Buy Now"/>
</form>