Codeigniter paypal_lib IPN not working - php

Question

I am trying to capture when the user made a payment in paypal(sandbox). IPN was the answer for this but it seems I am not getting any response from it. I tried to put it in a log and even the DB but there are no data entering. I know IPN is a listener but I dunno why isnt working.. Any clarification and thoughts about this?
I am using codeigniter Paypal_Lib
Here are my script:
First I declared the fields
$this->paypal_lib->add_field('cmd','_cart');
$this->paypal_lib->add_field('upload','1');
$this->paypal_lib->add_field('business', $business_email);
$this->paypal_lib->add_field('return', site_url('invoice/payment_success/'.$invoice_id.'/'.$album_id));
$this->paypal_lib->add_field('cancel_return', site_url('invoice/payment_cancel/'.$invoice_id));
$this->paypal_lib->add_field('notify_url', site_url('invoice/payment_validate/'.$invoice_id)); // <-- IPN url
$this->paypal_lib->add_field('custom', $invoice_id); // <-- Verify return
Here is for my IPN , just checking if it works by having a log but no luck.
public function payment_validate(){
//$this->paypal_lib->dump();
$invoice_id = $this->uri->segment(3);
if ($this->paypal_lib->validate_ipn()){
$payer_email = $this->paypal_lib->ipn_data['payer_email'];
$fp=fopen('temp/logs/paypal_ipn.log','a');
fwrite($fp, $this->paypal_lib->ipn_data . "\n");
fclose($fp); // close file
}
}
And here is the validate_ipn in the library.
function validate_ipn()
{
// get instance
$CI =& get_instance();
// parse the paypal URL
$url_parsed = parse_url($this->paypal_url);
// generate the post string from the _POST vars aswell as load the
// _POST vars into an arry so we can play with them from the calling
// script.
$post_string = '';
#if(count($_POST))
if($_POST)
{
#foreach (array_keys($_POST) as $field)
foreach ($_POST as $field => $value)
{
#$value = $CI->input->post($field, true);
$this->ipn_data[$field] = $value;
$post_string .= $field.'='.urlencode(stripslashes($value)).'&';
}
}
$post_string.='cmd=_notify-validate'; // append ipn command
// open the connection to paypal
$fp = fsockopen($url_parsed['host'],'80',$err_num,$err_str,30);
if(!$fp)
{
// could not open the connection. If loggin is on, the error message
// will be in the log.
$this->last_error = 'fsockopen error no. '.$err_num.': '.$err_str;
$this->log_ipn_results(false);
return false;
}
else
{
// Post the data back to paypal
fputs($fp, "POST $url_parsed[path] HTTP/1.1\r\n");
fputs($fp, "Host: $url_parsed[host]\r\n");
fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
fputs($fp, "Content-length: ".strlen($post_string)."\r\n");
fputs($fp, "Connection: close\r\n\r\n");
fputs($fp, $post_string . "\r\n\r\n");
// loop through the response from the server and append to variable
while(!feof($fp))
$this->ipn_response .= fgets($fp, 1024);
fclose($fp); // close connection
}
if (eregi('VERIFIED',$this->ipn_response))
{
// Valid IPN transaction.
if ($this->ipn_log_method == 'db')
{
return $this->log_ipn_results(true);
}
/*// Valid IPN transaction.
$this->log_ipn_results(true);*/
return true;
}
else
{
// Invalid IPN transaction. Check the log for details.
$this->last_error = 'IPN Validation Failed.';
$this->log_ipn_results(false);
return false;
}
}

Answer 1

Answering my own question:
Unable to receive paypal IPN because there's a problem when connecting to paypal , fixing this issue all you have to do is to change the port from:
$fp = fsockopen($url_parsed['host'],'80',$err_num,$err_str,30);
to
$fp = fsockopen($url_parsed['host'],'443',$err_num,$err_str,30);
Now receiving the connection is established and receiving paypal IPN notification.
Later part I experience that testing IPN in sandbox is failing and I found out that IPN in sandbox is not working. You can refer here

Answer 2

I know this is a silly question, but are you developing this on a localhost? The PayPal IPN may not be able to reach your server when you test it on localhost. Consider tools like PageKite, Localtunnel and etc to put your local computer to the internet so PayPal can reach it.
Another way is to login to the merchant sandbox account and view the IPN history to see exactly what's the error.