sopify-test-modul-fo/install.php

<?php 
include_once('config.php');

if(isset($_GET['shop']) && !empty($_GET['shop']))
{
    $install_url = "https://" . $_GET['shop'] . "/admin/oauth/authorize?client_id=" . API_KEY . "&scope=" . SCOPES . "&redirect_uri=" . urlencode(REDIRECT_URI) . "&state=" . NONCE;

    header("Location: " . $install_url);
    die();
}
else
{
    echo '<p>' . SHOP_REQUIRED . '</p>';
    echo '<p>Example: https://facturis-online.ro/plugins/shopify_app/install.php?shop=my-shop</p>';
}