Is it possible to pass the amount back to my site

Question

I am new to developer.paypal.com and i am creating a subscribe button in www.sandbox.paypal.com,is it possible to pass back the amount paid for the subscription by the customer to my website or the details that have been made in www.sandbox.paypal.com?if it is, can you show me some example on how to do this.

after i tried the subscription button this are the value returned i could not find some value in the link that you provided.or the subscription variable how can i show them up?

I could not get the start date and the ending date of my subscription Thank you.

Answer 1

You could do this one of two ways. You could use IPN or PDT to return information to your site once a payment completes. The better of the two ways, would be to use IPN, or atleast use IPN in conjunction with PDT.

Instant Payment Notification (IPN) is a message service that notifies you of events related to PayPal transactions. You can use it to automate back-office and administrative functions, such as fulfilling orders, tracking customers, and providing status and other information related to a transaction.

You can find more on IPN the page here. Also on that page, off to the left hand side are some more links that are useful as well. There are pages for creating a listener, setup, testing, IPN history, IPN with FMF, IPN/PDT variables, and sample code here. There are also a few more examples of sample code here as well.

PayPal’s PDT system sends order confirmations to merchant sites that use PayPal Payments Standard and lets them authenticate this information. Such sites can then display this data locally in an “order confirmation” page. IPN is more reliable than PDT, and also with PDT it is dependent on the buyer clicking a button to return to your site. If they they dont click on the button to return to your site, no information is sent back and you can not resend this information like you can with IPN. You can find more on PDT here.

I personally only use PDT for crating a dynamic thank you page on my site, and use IPN for updating my database and automating some tasks. Hope this helps. :)

SAMPLE PHP (v5.2) IPN SCRIPT

<?php

// 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

$ch = curl_init('https://www.paypal.com/cgi-bin/webscr');
curl_setopt($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, array('Connection: Close'));

// In wamp like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path 
// of the certificate as shown below.
// curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
if( !($res = curl_exec($ch)) ) {
    // error_log("Got " . curl_error($ch) . " when processing IPN data");
    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 = $_POST['receiver_email'];
    $payer_email = $_POST['payer_email'];
} else if (strcmp ($res, "INVALID") == 0) {
    // log for manual investigation
}
?>

SAMPLE PDT PHP (v5.3) SCRIPT

<?php

$pp_hostname = "www.paypal.com"; // Change to www.sandbox.paypal.com to test against sandbox


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

$tx_token = $_GET['tx'];
$auth_token = "GX_sTf5bW3wxRfFEbgofs88nQxvMQ7nsI8m21rzNESnl_79ccFTWj2aPgQ0";
$req .= "&tx=$tx_token&at=$auth_token";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://$pp_hostname/cgi-bin/webscr");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
//set cacert.pem verisign certificate path in curl using 'CURLOPT_CAINFO' field here,
//if your server does not bundled with default verisign certificates.
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Host: $pp_hostname"));
$res = curl_exec($ch);
curl_close($ch);

if(!$res){
    //HTTP ERROR
}else{
     // parse the data
    $lines = explode("\n", $res);
    $keyarray = array();
    if (strcmp ($lines[0], "SUCCESS") == 0) {
        for ($i=1; $i<count($lines);$i++){
        list($key,$val) = explode("=", $lines[$i]);
        $keyarray[urldecode($key)] = urldecode($val);
    }
    // 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
    $firstname = $keyarray['first_name'];
    $lastname = $keyarray['last_name'];
    $itemname = $keyarray['item_name'];
    $amount = $keyarray['payment_gross'];

    echo ("<p><h3>Thank you for your purchase!</h3></p>");

    echo ("<b>Payment Details</b><br>\n");
    echo ("<li>Name: $firstname $lastname</li>\n");
    echo ("<li>Item: $itemname</li>\n");
    echo ("<li>Amount: $amount</li>\n");
    echo ("");
    }
    else if (strcmp ($lines[0], "FAIL") == 0) {
        // log for manual investigation
    }
}

?>


Your transaction has been completed, and a receipt for your purchase has been emailed to you.<br> You may log into your account at <a href='https://www.paypal.com'>www.paypal.com</a> to view details of this transaction.<br>