PayPal IPN in PHP

[PHPiSean]

Hey guys, I am trying to learn about shopping carts in PHP. I want to make a site which only uses the method of PayPal. In that sense, how difficult is it to learn the methods to do so. Also does the PHP IPN allow me to create a shopping cart, and not go strait to the checkout? Thanks!

[phpSensei]

Paypal doesn't create the shopping cart in sense that it builds a site for you, it only handles the check out and send back a message to your IPN HANDLE script to give it the result... They have a server, check the link below, that offers a shopping cart API

 

here's an example

 

For different languages IPN:

 

https://cms.paypal.com/ca/cgi-bin/?&cmd=_render-content&content_ID=developer/library_code_ipn_code_samples

 

For PHP

 

// PHP 4.1

// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';

foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$req .= "&$key=$value";
}

// post back to PayPal system to validate
$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);

// 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 (!$fp) {
// HTTP ERROR
} else {
fputs ($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "VERIFIED") == 0) {
// check the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your Primary PayPal email
// check that payment_amount/payment_currency are correct
// process payment
}
else if (strcmp ($res, "INVALID") == 0) {
// log for manual investigation
}
}
fclose ($fp);
}
?>

 

 

They do however have a Paypal Shopping Cart Service like this one

 

https://merchant.paypal.com/ca/cgi-bin/?cmd=_render-content&content_ID=merchant/wp_standard

[phpSensei]

OP I re-read your question, I still answered it however, ignore the first part where I thought you wanted Paypal to actually make a site, I am very very ill minded tonight.

 

It can build a shopping cart before a checkout yes.

[PHPiSean]

OP I re-read your question, I still answered it however, ignore the first part where I thought you wanted Paypal to actually make a site, I am very very ill minded tonight.

 

It can build a shopping cart before a checkout yes.

Haha, it's fine. I just have not gotten involved with PHP and PayPal yet, but I'd like to. My worry is this.

 

I want to create a site where people can add and remove things from their shopping cart, just any eCommerce site in a sense. I am curious when I need to cut off the PHP and MySQL part and hand that over to PayPal. I guess you are suppose to use an IPN from what I heard.

[phpSensei]

Discussion is over through PM, topic solved.