<?php

// Connect to the MySQL database
$conn = new mysqli("hostname", "username", "password", "database_name");

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// Get the HTTP method, path and body of the request
$method = $_SERVER['REQUEST_METHOD'];
$request = explode('/', trim($_SERVER['PATH_INFO'],'/'));
$input = json_decode(file_get_contents('php://input'),true);

// retrieve the table and key from the path
$table = preg_replace('/[^a-z0-9_]+/i','',array_shift($request));
$key = array_shift($request)+0;

// create SQL based on HTTP method
switch ($method) {
    case 'GET':
        $sql = "select * from `$table`".($key?" WHERE id=$key":''); break;
    case 'PUT':
        $sql = "update `$table` set $set where id=$key"; break;
    case 'POST':
        $sql = "insert into `$table` set $set"; break;
    case 'DELETE':
        $sql = "delete `$table` where id=$key"; break;
}

// excecute SQL statement
$result = mysqli_query($conn,$sql);

// die if SQL statement failed
if (!$result) {
    http_response_code(404);
    die(mysqli_error());
}

// print results, insert id or affected row count
if ($method == 'GET') {
    if (!$key) echo '[';
    for ($i=0;$i<mysqli_num_rows($result);$i++) {
        echo ($i>0?',':'').json_encode(mysqli_fetch_object($result));
    }
    if (!$key) echo ']';
} elseif ($method == 'POST') {
    echo mysqli_insert_id($conn);
} else {
    echo mysqli_affected_rows($conn);
}

// close mysql connection
$conn->close();
?>