Proactive 404

proactive404.php

<?php
$http = str_replace('HTTP/1.1','http://',$_SERVER['SERVER_PROTOCOL']);
 
$datetime = date('Y-m-d H:i:s');
 
$to = $config['webmaster'];
    $subject = '404 at '. $config['url'];
    $headers = 'From: site@'.$config['url']."\r\n";
    $message = <<< MAIL
 
Date/Time: {$datetime}
The following URL fell on 404: $http{$_SERVER["SERVER_NAME"]}{$_SERVER["REQUEST_URI"]}
Redirect Url: {$_SERVER["REDIRECT_URL"]}
Referrer: {$_SERVER["HTTP_REFERER"]}
User Agent: {$_SERVER["HTTP_USER_AGENT"]}
Accept-Encoding: {$_SERVER["HTTP_ACCEPT_ENCODING"]}
 
Cookie: {$_ENV["HTTP_COOKIE"]}
 
Please fix it.
 
Sincerely- 404 Robot
 
MAIL;
 
    @mail($to, $subject, $message, $headers);
?>