<?php

  //set true if you want to use script for billing reports
  //first you need to enable them in your account
  $billing_reports_enabled = false;

  // check that the request comes from Fortumo server
  if(!in_array($_SERVER['REMOTE_ADDR'],
      array('81.20.151.38', '81.20.148.122', '79.125.125.1', '209.20.83.207'))) {
    die("Error: Unknown IP");
  }

  // check the signature
  $secret = ''; // insert your secret between ''
  if(empty($secret) || !check_signature($_GET, $secret)) {
    die("Error: Invalid signature");
  }

  $sender = $_GET['sender'];
  $message = $_GET['message'];

  // do something with $sender and $message
  $reply = "Thank you $sender for sending $message";

  // print out the reply
  echo($reply);

//customize this according to your needs
  if($billing_reports_enabled
    && preg_match("/Failed/i", $_GET['status'])
    && preg_match("/MT/i", $_GET['billing_type'])) {
   // find message by $_GET['message_id'] and suspend it
  }


  function check_signature($params_array, $secret) {
    ksort($params_array);

    $str = '';
    foreach ($params_array as $k=>$v) {
      if($k != 'sig') {
        $str .= "$k=$v";
      }
    }
    $str .= $secret;
    $signature = md5($str);

    return ($params_array['sig'] == $signature);
  }
?>