json_encode : values showing null - php

Question

<?php
require_once (realpath(dirname(__FILE__) . '/../includes/database.php'));
class User {
public $email;
public $password;
public function find_email($email, $password) {
global $database;
$pswd = substr(md5($password), 0, 25);
$results_array = self::find_by_sql("SELECT * FROM tbl_users where email_id='".$email."' AND password='".$pswd."'");
return !empty($results_array)? array_shift($results_array) : false;
}
public static function find_by_sql($sql){
global $database;
$results = $database -> query($sql);
$object_array = array();
while($row = $database -> fetch_array($results)){
$object_array[] = self::instantiate($row);
}
return $object_array;
}
public static function instantiate($row) {
$event = new self;
foreach($row as $attribute => $value) {
if($event -> has_attribute($attribute)) {
$event -> $attribute = $value;
}
}
return $event;
}
private function has_attribute($attribute) {
$object_vars = get_object_vars($this);
return array_key_exists($attribute, $object_vars);
}
}
if (isset($_GET['email']) && isset($_GET['password'])) {
$result = new User();
$result->find_email($_GET['email'], $_GET['password']);
echo json_encode($result);
}
?>
This is the login.php which is supposed to print out the json for the required user, but whenever I try to get the json, this is getting returned.
{"email":null,"password":null}
Any help would be appreciated. Thanks.

Answer 1

You don't do anything with the result of find_email. Your class doesn't update it's own properties when find_email is called. Instead, it returns a new instance of the class with the email and password properties set, so you need to capture the return value and encode that.
Change to:
$result = new User();
$user = $result->find_email($_GET['email'], $_GET['password']);
echo json_encode($user);
Side note: have a look at SOLID and Dependency Injection. DI would be preferred over having a global $Database.