<?php

    header('Content-Type: application/json; charset=utf-8');

    $file = "dynamic-data.json";

    if (isset($_GET['reset']) && $_GET['reset']) {

        $resetfile = "test-data.json";

        file_put_contents($file, file_get_contents($resetfile));

    }

    if (isset($_POST['data'])) {

        file_put_contents($file, $_POST['data']);

        echo json_encode(array("result" => "OK"));

    } else {

        echo file_get_contents($file);

    }

?>