对象未按预期启动PHP OOP

Question

I am new to php and OOP in general, so have decided to turn my existing site in an oo php one to gain some experience. Here is the issue I am currently facing.

I have a class Normaluser which is extending from User. Inside the User class is a login method which returns an object containing an array of the Users class' properties.

class NormalUser extends User {

public function __construct($loginarray){
    $email = $loginarray['email'];
    $pass = $loginarray['pass'];

    var_dump ( parent::login($email,$pass) );
    //return parent::login($email,$pass)
}
}

When doing a var_dump (as above) I get

bool(false) object(User)#8 (4) 
{ ["user_id"]=> string(1) "1" ["first_name"]=> string(7) "Melanie" ["last_name"]=> string(6) "Janson" ["user_level"]=> string(1) "1" }

Yet after calling the code in my login.php page :

$postdata = User::mysqli_array_escape($_POST);      

    $email = $postdata['email'];
    $pass = $postdata['pass'];

    $userstart = new NormalUser($postdata);
    var_dump($userstart);

I would think that calling $userstart as a new NormalUser object would return the correct variables, yet when I do a var_dump (as written in above) I receive the following :

object(NormalUser)#5 (4) 
{ ["user_id"]=> NULL ["first_name"]=> NULL ["last_name"]=> NULL ["user_level"]=> NULL }

I do not understand where I have gone wrong, If anyone would be able to point me in the right direction I would be greatly appreciative.

Thank you.

EDITED : added user.php login method as requested

    public static function login($email, $pass) {
    global $database;
    $sql = "SELECT user_id, first_name, last_name, user_level FROM users WHERE (email='$email' AND pass=SHA1('$pass')) AND active IS NULL LIMIT 1";
    $results = self::find_by_sql($sql);
    //var_dump($results);
    if (!empty($results)) {

        return array_shift($results);
    } else {
        return false;
    }

}

Answer 1

The problem is that you are returning an object in the constructor . This is not how constructors work.

I have two options for you:

1. Either you create a static method that returns a NormalUser instance (instead of using the constructor):

    // In your NormalUser class. static function createNormalUser($loginarray) { $email = $loginarray['email']; $pass = $loginarray['pass']; return parent::login($email,$pass); } 

2. Or you stick with the constructor but instead of returning an object instance, you assign its attributes to the $this instance:

    function __construct($loginarray) { $email = $loginarray['email']; $pass = $loginarray['pass']; $temp = parent::login($email,$pass); $this->user_id = $temp->user_id; // etc... } 

Answer 2

new NormalUser() creates a NormalUser object, which is completely distinct from the User object returned by User::login() . The User object is immediately lost because you don't assign it to anything.

One solution would be to assign each field manually:

class NormalUser extends User {

 public function __construct($loginarray){
  $email = $loginarray['email'];
  $pass = $loginarray['pass'];

  if($base = parent::login($email,$pass)) {
   $fields = array('user_id', 'first_name', 'last_name', 'user_level');
   foreach($fields as $fld) {
    $this->$fld = $base->$fld;
   }
  }
 }
}

but that feels wrong to me. Another option would be:

$email = $postdata['email'];
$pass = $postdata['pass'];

$userstart = NormalUser::login($postdata);
var_dump($userstart);

If my guess about the behaviour of your find_by_sql is correct, that should produce the result you want.