Simple Routing in PHP

index.php

<?php
$contextPath = '/pepcon';

$url = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : $contextPath;
$requestMethod = isset($_SERVER['REQUEST_METHOD']) ? $_SERVER['REQUEST_METHOD'] : 'GET';
$urlSegments = explode('/', rtrim($url));

echo 'URL: ' . $url . '<br>';
echo 'HTTP Method: ' . $requestMethod . '<br>';
echo '<pre>';
var_dump($urlSegments);
echo '</pre>';

$loggedUser = 'acalvarez';

if ($requestMethod == 'GET') {
    switch($url) {
        case $contextPath:                  // login
        case $contextPath . '/':            // login
        case $contextPath . '/index.php':   // login
            index();
            break;
        case $contextPath . '/homepage':   
            homepage();
            break;
        case $contextPath . '/' . $loggedUser:
            profile();
            break;
        default:
            users();
            error404();
            break;
    }
}

function index() {
    echo 'Login';
}

function homepage() {
    echo 'Home page';
}

function profile() {
    global $loggedUser;
    echo $loggedUser;
    echo '<br>profile';
}

function users() {
    $users = ['accruz', 'acsantos', 'acrodriguez']; // from db
    global $urlSegments;
    global $loggedUser;
    if (count($urlSegments) == 3) {
        $user = $urlSegments[2];
        if ($user != $loggedUser && in_array($user, $users)) {
            echo $user;
            echo '<br> other user';
            exit;
        } 
    }
    
}

function error404() {
    header("HTTP/1.0 404 Not Found");
    echo 'Error 404, page not found!';
}