Url

StaticPHP\Utils\Models\Url is three static methods that push strings around. It parses nothing, encodes nothing and validates nothing - for reading the current request’s url, see the router.

<?php

namespace StaticPHP\Utils\Models;

class Url
{
    public static function ensureSlash(string $string);
    public static function addTo(string $url, string $part);
    public static function join(array $parts);
}

Url::ensureSlash('/api/v1')                    => '/api/v1/'
Url::ensureSlash('/api/v1/')                   => '/api/v1/'
Url::ensureSlash('')                           => ''
Url::addTo('https://a.test', 'users')          => 'https://a.test/users'
Url::addTo('https://a.test/', 'users')         => 'https://a.test//users'
Url::join(['https://a.test', 'users'])         => 'https://a.test/users'
Url::join(['https://a.test/', '/users/', '7']) => 'https://a.test/users/7'
Url::join(['', 'users'])                       => '/users'

ensureSlash()

Appends / unless the string already ends in one. An empty string comes back empty, because the check is strlen($string) > 0 first - so it cannot turn '' into '/'.

addTo()

Literally "{$url}/{$part}". It does not look at what is already there, so a $url that ends in a slash gives you a double slash. Use it when you know both sides are clean.

join()

trim($item, '/') on every element, then implode('/'). This is the one to reach for when the pieces come from different places and may or may not carry slashes - it normalises the seams and nothing else.

Two things it does not do. Leading and trailing slashes are trimmed from the first and last elements too, so join(['https://a.test/', ...]) keeps the scheme’s // (they are interior) but a path built from ['/api', 'v1'] comes back as api/v1 without its leading slash. And an empty element stays in the list, contributing an empty segment, which is why join(['', 'users']) is /users.

<?php

use StaticPHP\Core\Models\Config;
use StaticPHP\Utils\Models\Url;

$base = Config::get('base_url');           // 'http://localhost/'
$href = Url::join([$base, 'billing', 'invoices', (string) $id]);

None of the three escapes anything. Values that come from user input have to be run through rawurlencode() before they go in.