Unable to Receive PayPal IPN Response in Code Igniter - php

Question

I have been at this for 3 days now and still can't get it to work.
What I want to do is to get PayPal response from the IPN listener so that I can modify my database accordingly, but no matter what I do, it just won't work. I have already done the following in my PayPal Sandbox account:
Enabled Auto Return
Set Auto Return URL ('paypal/success')
Enabled Payment Data Transfer (PDT)
Enabled IPN message reception
Set IPN URL ('paypal/ipn')
The redirect to Auto Return URL works fine and I receive the payment data in success page, but the IPN won't process for reasons beyond me. A quick look at the IPN history on my PayPal profile shows that the messages are being sent, but I don't receive them at my end.
Here is my current IPN listener: Paypal/ipn
public function ipn() {
//Build the data to post back to Paypal
$postback = 'cmd=_notify-validate';
// go through each of the posted vars and add them to the postback variable
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$postback .= "&$key=$value";
}
// build the header string to post back to PayPal system to validate
$header = "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header .= "Host: www.sandbox.paypal.com\r\n";//or www.sandbox.paypal.com
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($postback) . "\r\n\r\n";
// Send to paypal or the sandbox depending on whether you're live or developing
// comment out one of the following lines
$fp = fsockopen ('www.sandbox.paypal.com', 443, $errno, $errstr, 30);//open the connection
//$fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30);
// or use port 443 for an SSL connection
//$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
if ( ! $fp ) {
// HTTP ERROR Failed to connect
$message = 'HTTP ERROR Failed to connect!';
$this->email_me($message);
} else { // if we've connected OK
fputs ($fp, $header . $postback); //post the data back
while ( ! feof($fp) ) {
$response = fgets ($fp, 1024);
if (strcmp (trim($response), "VERIFIED") == 0) { //It's verified
//read the payment details and the account holder
$payment_status = $_POST['payment_status'];
$receiver_email = urldecode($_POST['receiver_email']);
// further checks
if( ($payment_status == 'Completed') && ($receiver_email == $this->business_email) ) {
$message = 'IPN verified successfully!';
$this->email_me($message);
// Insert the transaction data in the database
$this->product_model->insert_transaction_details($_POST);
} else {
$message = 'Payment could not be verified!';
$this->email_me($message);
}
} else {
$message = 'IPN invalid!';
$this->email_me($message);
}
}
}
}
Can someone point me in the right direction please?
Also, is there anyway I can check the IPN response ("VERIFIED" or "INVALID") on chrome debugger or in my PayPal Sandbox dashboard? I can see delivery status in my dashboard but it doesn't say 'Verified' or 'Invalid' anywhere.

Answer 1

I found the solution! I wrote the IPN handler inside a controller that allows access to users who are logged in as admin. Apparently, the IPN method was denying access to PayPal to verify the transaction. I figured this out and wrote the IPN method in a different controller and everything worked perfectly.
I also changed my IPN handler to this code (although the original might still work... i didn't try it):
class Paypal_ipn extends MY_Controller {
public function __construct() {
parent::__construct();
$this->load->model('product_model');
$this->sandbox = $this->config->item('sandbox');
$this->paypal_host = $this->config->item('paypal_host');
$this->paypal_url = $this->config->item('paypal_url');
$this->business_email = $this->config->item('business');
}
public function ipn() {
// STEP 1: Read POST data
// reading posted data from 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";
}
// STEP 2: Post IPN data back to paypal to validate
$ch = curl_init($this->paypal_url);
$headers = array(
'POST /cgi-bin/webscr HTTP/1.1',
'Host: ' . $this->paypal_host,
'Content-Type: application/x-www-form-urlencoded; charset=utf-8',
'Content-Length: ' . strlen($req),
'User-Agent: PayPal-IPN-VerificationScript',
'Connection: Close'
);
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, $headers);
if( !($res = curl_exec($ch)) ) {
curl_close($ch);
exit;
}
curl_close($ch);
// STEP 3: Inspect IPN validation result and act accordingly
if (strcmp ($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 Primary PayPal email
// check that payment_amount/payment_currency are correct
// process payment
// 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'];
$receiver_email = urldecode($_POST['receiver_email']);
$payer_email = $_POST['payer_email'];
$school_id = $_POST['custom'];
// further checks
if($payment_status == 'Completed') {
$message = 'IPN verified successfully!';
$this->email_developer($message);
// Insert the transaction data in the database
$this->product_model->insert_transaction_details($_POST);
} else {
$message = 'Payment could not be verified!';
$this->email_developer($message);
}
} else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
$message = 'IPN Invalid!';
$this->email_developer($message);
}
}
}
For those that might experience my predicament, ensure you also do the following:
If you enabled Cross Site Request Forgery (CSRF), ensure the IPN listener/handler is whitelisted, else IPN message will fail (Error 403 in PayPal IPN history).
To be sure your IPN listener is working well, run it as a URL and see the response. If there is any error, it won't work. For response, trying echoing "Verified" or "Invalid".
Use the PayPal IPN Simulator to test the process. Include a procedure that will submit information to the database upon success.
I hope it helps someone.

Answer 2

use php://input instead of $_POST
reson described here in details : PHP "php://input" vs $_POST
also paypal has documentation for implementing IPN Listener and its in php as well
Paypal tutorial