A perfectly normal redirector

perfectlyNormalRedirector.php

<?php

$realMappings = [
    '/aa124e' => 'https://www.ctv.ca/'
];

$hiddenMappings = [
    '/aa124e' => 'https://www.cbc.ca/'
];

$hideFrom = [
    'twitter' => '/Twitterbot/'
];

$safePerson = true;

$userAgent = $_SERVER['HTTP_USER_AGENT'];
foreach ($hideFrom as $source => $regex) {
    if (preg_match($regex, $userAgent)) {
        $safePerson = false;
        break;
    }
}

$pathInfo = $_SERVER['PATH_INFO'];
if (!array_key_exists($pathInfo, $realMappings)) {
    http_response_code(404);
    exit(1);
}

$url = $safePerson ? $realMappings[$pathInfo] : $hiddenMappings[$pathInfo];
http_response_code(301);
header('Location: ' . $url);
header('Content-Type: text/plain');

echo "Bye";