/**
* Retrieve client information and save it into an array
*/
$client_info = array ();

/**
* Regular expression for a valid IP address
*/
$IP_EXPRESSION = "/^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})/";


/**
* Get IP address of current visitor
*/
$client_info['IP'] = (!empty ($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : ((!empty ($_SERVER['HTTP_X_FORWARDED_FOR'])) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : @ getenv ('REMOTE_ADDR'));


/**
* Get alternate IP address of current visitor,
* like IP address behind a proxy
*/
if (isset ($_SERVER['HTTP_CLIENT_IP']))
{
   $client_info['IP_BEHIND_PROXY'] = $_SERVER['HTTP_CLIENT_IP'];
}
elseif (isset ($_SERVER['HTTP_X_FORWARDED_FOR']))
{
   /**
    * This gathered IP address is probably behind a proxy
    * Do not rely on this and it doesn't make sense to block the whole proxy
    */
   preg_match_all ($IP_EXPRESSION.'s', $_SERVER['HTTP_X_FORWARDED_FOR'], $matches);


   /**
    * IP's defined by RFC 1918 are not saved
    * http://rfc.net/rfc1918.html
    */
   foreach ($matches[0] as $IP)
   {
      if (!preg_match ("/^(10|172\.16|192\.168)\./", $IP))
      {
         $client_info['IP_BEHIND_PROXY'] = $IP;
         break;
      }
   }
}
else
{
   $client_info['IP_BEHIND_PROXY'] = '';
}


/**
* Get the internet host name corresponding to a given IP address
*/
$client_info['HOSTNAME'] = @ gethostbyaddr ($client_info['IP']);


/**
* Contents of the User-Agent: header from the current request, if there is one
*/
$client_info['USER_AGENT'] = (!empty ($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : '');


/**
* The address of the page (if any) which referred the user agent to the current page
*/
/*$client_info['query_from'] = $_SERVER['HTTP_REFERER'];*/


/**
*The port being used on the user's machine to communicate with the web server
*/
$client_info['PORT'] = (!empty ($_SERVER['REMOTE_PORT']) ? $_SERVER['REMOTE_PORT'] : '');


/**
* The URI which was given in order to access this page
*/
if ($_SERVER['REQUEST_URI'] || $_ENV['REQUEST_URI'])
{
   $client_info['REQUEST_URI'] = $_SERVER['REQUEST_URI'] ? $_SERVER['REQUEST_URI'] : $_ENV['REQUEST_URI'];
}
else
{
   if ($_SERVER['PATH_INFO'] || $_ENV['PATH_INFO'])
      $client_info['REQUEST_URI'] = ($_SERVER['PATH_INFO'] ? $_SERVER['PATH_INFO'] : $_ENV['PATH_INFO']);
   elseif ($_SERVER['REDIRECT_URL'] || $_ENV['REDIRECT_URL'])
      $client_info['REQUEST_URI'] = ($_SERVER['REDIRECT_URL'] ? $_SERVER['REDIRECT_URL'] : $_ENV['REDIRECT_URL']);
   else
      $client_info['REQUEST_URI'] = ($_SERVER['PHP_SELF'] ? $_SERVER['PHP_SELF'] : $_ENV['PHP_SELF']);

   if ($_SERVER['QUERY_STRING'] || $_ENV['QUERY_STRING'])
      $client_info['REQUEST_URI'] .= '?'.($_SERVER['QUERY_STRING'] ? $_SERVER['QUERY_STRING'] : $_ENV['QUERY_STRING']);
}

/**
* The query string, if any, via which the page was accessed
*/
$client_info['QUERY_STRING'] = str_replace ('&', '&', urldecode ($_SERVER['QUERY_STRING'] ? $_SERVER['QUERY_STRING'] : @ getenv ('QUERY_STRING')));


/**
* Clean and repair client information
*/
$client_info['IP']              = preg_replace ("{$IP_EXPRESSION}", "\\1.\\2.\\3.\\4", $client_info['IP']);
$client_info['IP_BEHIND_PROXY'] = preg_replace ("{$IP_EXPRESSION}", "\\1.\\2.\\3.\\4", $client_info['IP_BEHIND_PROXY']);
$client_info['REQUEST_URI']     = str_replace ('&', '&', $client_info['REQUEST_URI']);
$client_info['QUERY_STRING']    = str_replace ('&', '&', $client_info['QUERY_STRING']);