API PayPal

/************payment-success.php***********/
$paypalemail = "ololo-ficilitator@gmail.com";     // e-mail продавца
  $currency    = "GBP";              // валюта
  
  //-------ТОЛЬКО ЕСЛИ SENDBOX-----------------------------------------
  $postdata=""; 
  foreach ($_POST as $key=>$value) $postdata.=$key."=".urlencode($value)."&"; 
  $postdata .= "cmd=_notify-validate"; 
  $curl = curl_init("https://www.sandbox.paypal.com/cgi-bin/webscr"); 
  curl_setopt ($curl, CURLOPT_HEADER, 0); 
  curl_setopt ($curl, CURLOPT_POST, 1); 
  curl_setopt ($curl, CURLOPT_POSTFIELDS, $postdata); 
  curl_setopt ($curl, CURLOPT_SSL_VERIFYPEER, 0); 
  curl_setopt ($curl, CURLOPT_RETURNTRANSFER, 1); 
  curl_setopt ($curl, CURLOPT_SSL_VERIFYHOST, 1); 
  $response = curl_exec ($curl); 
  curl_close ($curl); 
  if ($response != "VERIFIED") die("You should not do that ...");
  //------------------------------------------------------------------------
  
    if ($_POST['receiver_email'] != $paypalemail 
    || $_POST["txn_type"] != "web_accept") 
      die("You should not be here ...");
      
      $email = $_SESSION["email"];
    $getpoints = mysql_query("SELECT * FROM wp_auth WHERE email='$email'");
    $getdata = mysql_fetch_array($getpoints);
    $gross = $getdata["cost"];
    switch($_POST["mc_gross"]){
        case '4.50': $cost="3"; break;
        case '8.40': $cost="7"; break;
        case '15.40': $cost="14"; break;
        case '50.00': $cost="50"; break;
        case '90.00': $cost="100"; break;
        case '120.00': $cost="150"; break;
        case '140.00': $cost="200"; break;
    }
    $gross+=$cost;
    $wpdb = mysql_query("UPDATE 'wp_auth' SET cost = '$gross' WHERE email='$email'");

<?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
 
$ch = curl_init('https://www.paypal.com/cgi-bin/webscr'); // change to [...]sandbox.paypal[...] when using sandbox to test
curl_setopt($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', 'User-Agent: Legal Consulting'));
 
// 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 ($res, "VERIFIED") == 0) {
    echo "VERIFIED";
}
     else if (strcmp ($res, "INVALID") == 0) {
     echo "INVALID";
     }
?>