Slim 3-getParsedBody（）不正确的整数值：'NULL'

Question

This is my first attempt on Slim 3. I am trying to make a simple web application, but whenever I am trying to retrieve a NULL/Empty request parameter it's always a string, and trying to save the value into a numeric column will result in

General error: 1366 Incorrect integer value: 'NULL' for column 'last_login' at row 1

Validating each parameter seems like an exhausting task. I would like to know if that's my only option or there's something I'm missing.

I also had some issues trying to save an object with private fields into the database, so I would really appreciate any comments on my approach.

Table Design

CREATE TABLE `users` (
  `user_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `last_login` datetime DEFAULT NULL,
  PRIMARY KEY (`user_id`)
)

---

User Model

class User implements JsonSerializable
{

    private $user_id;
    private $name;
    private $last_login;

    public function __construct($user_id = null, $name = null, $last_login = null)
    {
        if ($user_id !== null) $this->user_id = $user_id;
        if ($name !== null) $this->name = $name;
        if ($last_login !== null) $this->last_login = $last_login;
    }

    /**
     *  Getters and setters
     */

    function jsonSerialize()
    {

        return get_object_vars($this);
    }
}

---

UserDAO

class UserDAO
{

    public function addUser(User $user)
    {

        $query = $this->connection->prepare('INSERT INTO ' . TABLE_USERS . ' VALUE (:user_id, :name, :last_login)');
        $result = $query->execute((array)$user->jsonSerialize());

        return $result;
    }
}

Not calling jsonSerialize() on execute will result in

'PDOException' with message 'SQLSTATE[HY093]: Invalid parameter number: parameter was not defined

I assume PDO can't access model's private fields, I could be wrong tho.

---

Routes

$app->post('/user/add', function (Request $request, Response $response) {

    $input = $request->getParsedBody();

    $userDAO = new UserDAO();

    $id = $input['user_id'];
    $name = $input['name'];
    $last = $input['last_login'];

    // Set ID as NULL to show the difference dump between ID and Last_login
    $user = new User(null, $name, $last);

    var_dump($input);
    var_dump($user);

    $userDAO->addUser($user);
});

---

Dump Result

C:\wamp64\www\Rest\app\core\Routes.php:61:
array (size=3)
  'user_id' => string 'NULL' (length=4)
  'name' => string 'B' (length=1)
  'last_login' => string 'NULL' (length=4)

C:\wamp64\www\Rest\app\core\Routes.php:62:
object(User)[59]
  private 'user_id' => null
  private 'name' => string 'B' (length=1)
  private 'last_login' => string 'NULL' (length=4)

I guess that's the whole issue, how to turn this string 'NULL' into NULL in an efficient way.

---

The insert method works just fine after adding jsonSerialize() on excute. Tried calling addUser() from index.php and data get inserted into database.

Sorry for the long post, but I've tried to remove a lot of fields for simplicity without leaving any relative code out.

Answer 1

All data in the Request object are strings. Hence, if it's string "NULL" you need to manually convert it to null .

The easiest way to solve this problem is to stop inserting user_id as it's an auto increment field. ie the correct SQL statement to prepare is:

$query = $this->connection->prepare('INSERT INTO ' . TABLE_USERS 
    . ' (name, last_login) VALUE (:name, :last_login)');