PHP Decode

 <?php 
 header('Access-Control-Allow-Origin: *'); 
 header('Access-Control-Allow-Headers: access'); 
 header('Access-Control-Allow-Methods: POST,PUT'); 
 header('Content-Type: application/json; charset=UTF-8'); 
 header('Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With'); 
 session_start(); 
  
 class Connection { 
     public $host = "localhost"; 
     public $user = "root"; 
     public $password = ""; 
     public $dbname = "task2"; 
     public $conn; 
  
     public function __construct() { 
         $this->conn = new mysqli($this->host, $this->user, $this->password, $this->dbname); 
  
         if ($this->conn->connect_error) { 
             
             die("Connection failed: " . $this->conn->connect_error); 
         } 
 
     } 
 
 }   
//  $data = json_decode(file_get_contents('php://input'));   
//  $username= $data->username; 
//  $password= $data->password; 
//  $email= $data->email; 
//  $result = $register-> registration($username,$password,$email); 
     
 class Register extends Connection { 
    $data = json_decode(file_get_contents('php://input')); 
    if ($data && isset($data["username"]) && isset($data["email"]) && isset($data["password"])) { 
        $username = $data["username"]; 
        $email = $data["email"]; 
        $password = $data["password"];} 
 
 
     public function registration($username, $password, $email) { 
         $duplicate = mysqli_query($this->conn, "SELECT * FROM users WHERE email = '$email'"); 
         if (mysqli_num_rows($duplicate) > 0) { 
             return 10; // User with the same email already exists 
         } else { 
             $hashedPassword = password_hash($password, PASSWORD_DEFAULT); 
             $query = "INSERT INTO users (username, password, email) VALUES ('$username', '$hashedPassword', '$email')"; 
             mysqli_query($this->conn, $query); 
             return 1; // Registration successful 
         } 
     } 
 } 
  
 class Select extends Connection { 
     public function selectUserById($id) { 
         $result = mysqli_query($this->conn, "SELECT * FROM users WHERE id='$id'"); 
         return mysqli_fetch_assoc($result); 
     } 
 } 
 ?>