record-requests.php

<?php

$headers = getallheaders();
$contents = $_SERVER['REQUEST_METHOD'] . ' ' . $_SERVER['REQUEST_URI'] . ' ' . $_SERVER['SERVER_PROTOCOL'] . PHP_EOL;

foreach ($headers as $key => $value) {
    $contents .= $key . ': ' . $value . PHP_EOL;
}

$contents .= PHP_EOL . file_get_contents('php://input');
file_put_contents(sys_get_temp_dir() . '/request-' . microtime(true) . '.log', $contents);