index.php

<?php


$vars = [];

if (!$_POST) {
    $_POST = json_decode(file_get_contents('php://input'), true);
    $_POST['content-type'] = $_SERVER['HTTP_CONTENT_TYPE'] ?? '?';
}

foreach ($_SERVER as $k => $v) {
    switch ($k) {
        default:
            if (0 !== strpos($k, 'HTTP_')) {
                continue 2;
            }
        // no break
        case 'SERVER_NAME':
        case 'SERVER_PROTOCOL':
        case 'REQUEST_URI':
        case 'REQUEST_METHOD':
        case 'PHP_AUTH_USER':
        case 'PHP_AUTH_PW':
            $vars[$k] = $v;
    }
}

$json = json_encode($vars, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);

header('Content-Type: application/json', true);

switch ($vars['REQUEST_URI']) {
    case '/long-to-execute':
        flush();
        sleep(5);
        break;
    case '/faster':
        flush();
        sleep(1);
        break;
}


echo $json;