PHP error notices. Should they never be ignored? - php

Question

I'm researching how to better organize my website content with PHP, and I had a question regarding unimportant error notices.
<?php
switch ($_GET['filename']) {
case 'home':
require('src/home.php');
break;
case 'quiz';
require('src/quiz.php');
break;
default:
if ($_GET['filename'] == '') {
include('src/home.php');
} else {
header('HTTP/1.0 404 Not Found');
include('src/page_not_found.php');
}
break;
}
?>
For example here; it's obviously telling me that it's getting undefined when I try to get the filename in the URL parameter. In this context, it's empty, and I'm doing this on purpose to check if there's something in there and if it should be interpreted as one of my other files.
I'm aware that you can add "error_reporting(E_ERROR | E_PARSE);" at the start of the line to hide the notice and the website will work just fine like that, but I was wondering if this is something I should always "fix"?
I was thinking of doing an if condition before the switch case:
if ($_GET['filename'] == ""){
include('src/home.php');
}
But that will throw me a notice as well, since what I am checking is undefined and will trigger the error notice regardless. What should I do?

Answer 1

Tim Lewis answered my question, thank you by the way!; Instead of hoping that a file is there, you can instead use isset().
So, instead of what I made, I would do something like this, to first check if the content is set before doing anything else:
<?php
if (!isset($_GET['filename'])){
include('src/home.php');
} else {
switch ($_GET['filename']) {
case 'home':
require('src/home.php');
break;
case 'quiz';
require('src/quiz.php');
break;
default:
header('HTTP/1.0 404 Not Found');
include('src/page_not_found.php');
break;
}
}
?>