PHP Scripting Issue

[harux10m]

Hello!
I used to have an old website where my links were used like this:
[domainname]/site/?id=about
[domainname]/site/?id=contact

instead of:
[domainname]/site/about.php
[domainname]/site/contact.php

using the following code:

<?php
    $code = $_GET['error'] or
    $code = $_GET['guide'] or
    $code = $_GET['id'] or
    $code = $_GET['msg'] or
    $code = $_GET['mybid'] or
    $code = $_GET['x'];
    if (!empty($code)) {
        $code .= '.php'; 
    if (!file_exists($code)) {
    include($_SERVER['DOCUMENT_ROOT'] . "/site/404.php");
    }
    else {
    include($code);
    }
    }
    else {
    include($_SERVER['DOCUMENT_ROOT'] . "/site/scripts/html/index.html");
    }
?>

So to explain, I had several $code's, which some of my pages were using ?id= while others were using ?guide=, etc.

And when the link that was ?id=about or ?id=contact was not valid, it would send users to the 404 page, but if it existed, it would go to the direct page (ie. about.php).

However, I also set it to where if someone accessed the folder directly ([domainname]/site), it would send to the index.html page which redirects to the mainpage.

But since I am on a new server now and using the same script, it's causing me errors by stating:
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: error in /home/harux10m/public_html/site/scripts/php/getCode.php on line 2
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: guide in /home/harux10m/public_html/site/scripts/php/getCode.php on line 3
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: id in /home/harux10m/public_html/site/scripts/php/getCode.php on line 4
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: msg in /home/harux10m/public_html/site/scripts/php/getCode.php on line 5
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: mybid in /home/harux10m/public_html/site/scripts/php/getCode.php on line 6
[01-Sep-2014 02:45:37 America/New_York] PHP Notice: Undefined index: x in /home/harux10m/public_html/site/scripts/php/getCode.php on line 7

I googled and it says I need to do an isset function now, but is there a way to alter the coding I have above to match it up?

Please let me know if you're confused or something.

But thanks in advance if anyone can assist!

PS [ The code works as usual, but I keep getting an error_log file generated. ]

 

[ttbx10ho]

I write it a little different and use an array. Get no errors and every thing works. had to edit htaccess ErrorDocument 404 /?p=404

<?php
$pages = array (
  index => array('name' => 'home' , 'title' => 'Hello World!' , 'page' => 'pages/home.php')
  about => array('name' => 'about' , 'title' => 'About' , 'page' => 'pages/about.php'),
  403 => array('name' => '403' , 'title' => '403 Forbidden' , 'page' => 'pages/403.php'),
  404 => array('name' => '404' , 'title' => '404 Not Found' , 'page' => 'pages/404.php')
   );

  if (isset ($_GET['p'])) {
    $pageID = $_GET['p'];
    if (! isset($pages[$pageID])) $pageID = 404;
  }
else {
    $pageID = index;
  }
define('this_page', $pages[$pageID]['name']);
?>

This code in between the head title tags

<?php echo $pages[$pageID]['title']; ?>

Then this code goes where ever you want your page to display.

<?php include $pages[$pageID]['page']; ?>

I been wanting to improve it so that it looks in the /pages folder and if anything.php is there it will display if not 404.php. But its a work in progress. I'm working on it at http://ttb.x10host.com/ its slow but will have a zip file with a complete template.