kaiser / Wordpress 404-Mail-Notification

<?php
/*
Plugin Name: 404-Deamon
Plugin URI: http://not-going-to-come-anytime.com
Description: Mails you a 404-Notification. This will even send you an email if you have got a missing favicon. It can be a little bit annoying, when you get mails for all crap of stuff. Feel free to extend the exclusions at the bottom. Currently it only excludes 404 if the admin lands on non-existand URLs or google and yahoo! visits you (props: toscho).
Version: 0.1
Author: Franz Josef Kaiser, Thomas Scholz a.k.a toscho
Author URI: http://unserkaiser.com, http://toscho.de
License: GPL2
*/

    // for Wordpress only: Your WP-URL
    $page_uri = get_bloginfo('url');
        // if you, like me: LOOOOOVE Pods, then go and grap a copy over at http://podscms.com
        if (function_exists(pods_url_variable)) {
            $page_uri_last = pods_url_variable('last');
        }

    // or stick with a simple PHP-Function
    // if you don't use WP, then use the following lines
    function full_non_wp_uri() {
        $page_uri_basic = 'http';
        if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";}
            $page_uri_basic .= "://";
        if ($_SERVER["SERVER_PORT"] != "80") {
            $page_uri_basic .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
        } else {
            $page_uri_basic .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
        }
        return $page_uri_basic;
    }

    // non-WP Users won't need to following lines too
    // set up the current User to get some data about him/her
    global $current_user;
    get_currentuserinfo();
        // Let's see, if it's registered User, or an unknown Guest
        if( is_user_logged_in() ) {
            $user_mail = "The User ";
            $user_mail .= $current_user->user_login;
            $user_mail .= " (Mail: ";
            $user_mail .= $current_user->user_email;
            $user_mail .= ") has ";
        } elseif( !is_user_logged_in() ) {
            $user_mail = "A guest has ";
        }
    /* END WP-KILL HERE */

    // get some additional data about our users and guest
    // don´t forget to delete the data if it´s no enemy
    // we want to save the privacy of our users and guests
    (isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? $look_up_ip = $_SERVER['HTTP_X_FORWARDED_FOR'] : $look_up_ip = $_SERVER['REMOTE_ADDR'] );
    (isset($_SERVER['HTTP_USER_AGENT']) ? $guest_user_agent = addslashes($_SERVER['HTTP_USER_AGENT']) : '');
    (isset($_SERVER['HTTP_REFERER']) ? $guest_referer = addslashes($_SERVER['HTTP_REFERER']) : '');
    $guest_req_method = $_SERVER['REQUEST_METHOD'] . ' http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];

    // the WP-way to give you some love
    $to = get_bloginfo('admin_email');
    $subject = "(ae) - 404";
    $message = "Dear Admin!\n\n";
        $message .= "Notification:\n";
        $message .= $user_mail;
        $message .= "tried to reach a page that\'s not here (";
        $message .= $page_uri;
        // quick'n'dirrrrty @pods
        if (function_exists(pods_url_variable)) {
            $message .= $page_uri;
            $message .= "/";
            $message .= $page_uri_last;
        } else {
            $message .= $page_uri_basic;
        }
        $message .= ") aufzurufen.\n\n";
        $message .= "Users Agent:";
        $message .= $guest_user_agent;
        $message .= "\n";
        $message .= "Referer:";
        $message .= $guest_referer;
        $message .= "\n";
        $message .= "Request Method:";
        $message .= $guest_req_method;
        $message .= "\n";
        $message .= "IP: http://ip-lookup.net/?ip=";
        $message .= $look_up_ip;
        $message .= "\n\n";
            $message .= "Yours friendly 404-Deamon from the neighborhood\n";
            $message .= "-----------\n";
            $message .= "That\'s an automatic mail.\n";
            $message .= "Please don\'t answer.\n";
            $message .= "I\'m too shy to reply.\n";
            $message .= "-----------";

    $headers = "From: from 404-Deamon with love <fehler_404@aerztejobs10.at>\r\n\\";
    $attachments = '';

    // Start: This part isn't working at the moment.. don't know why
    $content_type = "text/html";
    apply_filters( 'wp_mail_content_type', $content_type );
    // End: but it doesn't hurt anyway

        if( $current_user->user_email == get_bloginfo('admin_email') ) {
        } elseif( ! ( FALSE !== strpos($_SERVER['REQUEST_URI'], 'noexist' ) or FALSE !== strpos($_SERVER['REQUEST_URI'], 'SlurpConfirm') ) ) {
        } else {
            // Let's go with WP. The WP-Filter-Deamon will handle this for us (hopefully)
            add_filter('404_template', 'notify_404');

            function notify_404($deamon)
            {
                wp_mail( $to, $subject, $message, $headers, $attachments );
            return $deamon;
            }
        }

    // the PHP & toscho way to give you some love
    /*
    'MIME-Version: 1.0' . "\r\n"
        . 'Content-Type: text/plain; charset=UTF-8' . "\r\n"
        . 'Content-Transfer-Encoding: 8bit' . "\r\n"
        . 'From: from 404-Deamon with love <mail@' . $_SERVER['HTTP_HOST'] . '>' . "\r\n"
        . 'List-Id: "404" 404.List' . "\r\n"
    );
    */

// that's all folks
?>