/builder2/elements/pix_mail/paypal_ipn.php

<?php
// FLATPACK - Paypal forms ipn emails notifications
// By PixFort
// http://pixfort.com
// Copyright PixFort 2016

// 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");

include("config.php");

$subject = "FLATPACK PayPal Form Notification";

// 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_SSLVERSION, 4);
// curl_setopt($ch, CURLOPT_SSL_CIPHER_LIST, "TLSv1");
curl_setopt($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);
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: $res" . PHP_EOL, 3, LOG_FILE);
if (curl_errno($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: $res" . PHP_EOL, 3, LOG_FILE);
		}
		curl_close($ch);
}

// Inspect IPN validation result and act accordingly

// Split response headers and payload, a better way for strcmp
$tokens = explode("\r\n\r\n", trim($res));
$res = trim(end($tokens));

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'];
	$payer_fname = $_POST['first_name'];
	$payer_lname = $_POST['last_name'];


	if($receiver_email){$to_Email=$receiver_email;}
	$msg_header = "Thank you for your purchase.<br>";
	$final_msg = "Item Name : " . $item_name . "<br>";
	$final_msg .= "Item Number : " . $item_number . "<br>";
	$final_msg .= "Payment status : " . $payment_status . "<br>";
	$final_msg .= "Payment amount : " . $payment_amount . "<br>";
	$final_msg .= "Payment currency : " . $payment_currency . "<br>";
	$final_msg .= "txn_id : " . $txn_id . "<br>";
	$final_msg .= "Receiver email : " . $receiver_email . "<br>";
	$final_msg .= "Payer email : " . $payer_email . "<br>";
	$final_msg .= "Payer First Name : " . $payer_fname . "<br>";
	$final_msg .= "Payer First Name : " . $payer_lname . "<br>";
	$final_msg .= "<br>---------------------------------------------------<br>";
	$msg_footer = "Paypal Payment Form by PixFort<br>";
	$msg_footer .= "Envato: http://themeforest.net/user/pixfort<br>";
	$msg_footer .= "Website: http://pixfort.com<br>";

	$headers = 'From: '.$to_Email.'' . "\r\n" .
	'Reply-To: '.$to_Email.'' . "\r\n" .
	'X-Mailer: PHP/' . phpversion().'' . "\r\n" .
	"Content-Type: text/html;charset=utf-8";
	
	$seller_msg = $final_msg . $msg_footer;
	$buyer_msg = $msg_header . $final_msg;
	// send mail
	$sentMail1 = @mail($to_Email, $subject, $seller_msg, $headers);
	$sentMail2 = @mail($payer_email, $subject, $buyer_msg, $headers);

	if(!$sentMail1) {
		error_log(date('[Y-m-d H:i e] '). "PixFort Notification sentMail1 send failed". PHP_EOL, 3, LOG_FILE);
	}else{
		error_log(date('[Y-m-d H:i e] '). "PixFort Notification sentMail1 sent successfully". PHP_EOL, 3, LOG_FILE);
	}
	if(!$sentMail2) {
		error_log(date('[Y-m-d H:i e] '). "PixFort Notification sentMail2 send failed". PHP_EOL, 3, LOG_FILE);
	}else{
		error_log(date('[Y-m-d H:i e] '). "PixFort Notification sentMail2 sent successfully". PHP_EOL, 3, LOG_FILE);
	}
	
	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);
	}
}

?>