listener.php

<?php

  // Send an empty HTTP 200 OK response to acknowledge receipt of the notification
  header('HTTP/1.1 200 OK');
  // Assign payment notification values 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'];
  $txn_type         = $_POST['txn_type'];
  $steamid          = str_replace("STEAM_0","STEAM_1",$_POST['option_selection2']); //Custom Field
  $receiver_email   = $_POST['receiver_email'];
  $payer_email      = $_POST['payer_email'];
  writeMsg($txn_type . " " . $steamid . " " . $receiver_email);
  $req = 'cmd=_notify-validate';               // Add 'cmd=_notify-validate' to beginning of the acknowledgement

  foreach ($_POST as $key => $value) {         // Loop through the notification NV pairs
    $value = urlencode(stripslashes($value));  // Encode these values
    $req  .= "&$key=$value";                   // Add the NV pairs to the acknowledgement
  }

  $header = "POST /cgi-bin/webscr HTTP/1.1\r\n";
  $header .= "Content-Type: application/x-www-form-urlencoded\r\n";
  $header .= "Host: www.paypal.com\r\n";
  $header .= "Connection: close\r\n";
  $header .= "Content-Length: " . strlen($req) . "\r\n\r\n";

  // Open a socket for the acknowledgement request
  $fp = fsockopen('ssl://www.paypal.com', 443, $errno, $errstr, 30);

  // Send the HTTP POST request back to PayPal for validation
  fputs($fp, $header . $req);
  while (!feof($fp)) {                     // While not EOF
    $res = fgets($fp, 1024);               // Get the acknowledgement response
    $res = trim($res);
    fwrite($myfile, $res);
    if (strcmp ($res, "VERIFIED") == 0) {  // Response contains VERIFIED - process notification
      $servername = "1.1.1.1";
      $username = "username";
      $password = "password";
      $dbname = "store";

      $conn = new mysqli($servername, $username, $password, $dbname);

      if ($conn->connect_error) {
        writeMsg("Connection failed: " . $conn->connect_error);
      }

      //Do Stuff

    }
    else if (strcmp ($res, "INVALID") == 0) { // Response contains INVALID - reject notification

      //Invalid
    }
  }

  function writeMsg($message) {
    $file = 'log.txt';
    $current = file_get_contents($file);
    $current .= date("D M j G:i:s") . " - " . $message . "\n";
    file_put_contents($file, $current);
  }