RewriteEngine On # Turn on the rewriting engine
RewriteRule ^users/?$ users.php [NC,L]
RewriteRule ^users/([0-9]+)/?$ users.php?id=$1 [NC,L]

<?php
// Connect to database
include("../connection.php");
$db = new Database();
$connection = $db->getConnstring();

$request_method = $_SERVER["REQUEST_METHOD"];

switch($request_method) {
    case 'GET':
    // Retrieve Users
    if (!empty($_GET["user_id"])) {
        $id = intval($_GET["user_id"]);
        get_users($user_id);
    } else {
        get_users();
    }
    break;

    case 'POST':
    // Create User
    create_user();
    break;

    default:
    // Invalid Request Method
    header("HTTP/1.0 405 Method Not Allowed");
    break;
}

function get_users($user_id=0) {
    global $connection;
    $query = "SELECT * FROM user";
    if ($user_id != 0) {
        $query .= "Where user_id=" . $user_id . "LIMIT 1";
    }
    $response = array();
    $result = mysqli_query($connection, $query);
    while ($row=mysqli_fetch_array($result)) {
        $response[] = $row;
    }
    header('Content-Type: application/json');
    echo json_encode($response);
}

function create_user() {
    global $connection;

    $data = json_decode(file_get_contents('php://input'), true);
    $username = $data["username"];
    $email = $data["email"];
    $password = $data["password"];
    $confirm_password = $data["confirmPassword"];
    $status = 0;
    $user_role = 0;

    echo $query = "INSERT INTO user SET username='" . $username . "', email='" . $email . "', password='" . $password . "', confirm_password='" . $confirm_password . "', status='" . $status . "', user_role='" . $user_role . "'";

    if (mysqli_query($connection, $query)) {
        $response = array(
            'status' => 200,
            'message' => 'User Registered Successfully.'
        );
    } else {
        $response = array(
            'status' => 500,
            'message' => 'User Addition Failedl'
        );
    }
    header('Content-Type: application/json');
    echo json_encode($response);
}
?>