I’m using $_get for a simple page redirection. I’ve only just started learning about

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Asked: May 27, 20262026-05-27T19:08:36+00:00 2026-05-27T19:08:36+00:00

I’m using $_get for a simple page redirection. I’ve only just started learning about

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I’m using $_get for a simple page redirection.
I’ve only just started learning about sanitizing user input, so I was wondering if the below code was ok. Is there any other sanitization that is recommended for this particular code? If yes, why?

About the code below. I checked that the user entered a value and then matched the value against a list of acceptable values before redirecting.

$host  = $_SERVER['HTTP_HOST'];
$uri   = rtrim(dirname($_SERVER['PHP_SELF']), '/\\');
$PAGES = array('a', 'b', 'c', 'd', 'z');

if (empty($_GET['letter'])) { 
$_GET['letter']="a";
}

if (!in_array($_GET['letter'], $PAGES)) { 
$_GET['letter']="a";  
}

$letter=$_GET['letter']; 
$goto=$letter .".php";
header("Location: http://$host$uri/$goto");