Uncaught Error: Call to a member function buildUserData() - php

Question

Okay so heres the issue, I am trying to making a fancy login system that stores the users data in a php class so it is easy to access. However when I try to call the function that will build the user data it throws this exception.
Fatal error: Uncaught Error: Call to a member function buildUserData() on string in C:\xampp\htdocs\cfgs\submit\login.php:38 Stack trace: #0 {main} thrown in C:\xampp\htdocs\cfgs\submit\login.php on line 38
Here is the userData class code
<?php
class userData {
public $accId = null;
public $username = null;
public $rank = null;
public $vip_rank = null;
public $email = null;
public $auth = null;
function buildUserData($id) {
$result = $db->query("SELECT * FROM users WHERE id = '$id'");
while ($row = $result->fetch_assoc()) {
$this->accId = $id;
$this->username = $row['username'];
$this->rank = $row['rank'];
$this->vip_rank = $row['rank_vip'];
$this->email = $row['mail'];
$this->auth = $row['auth'];
}
}
}
?>
This is the login.php code
<?php
require_once '../../global.php';
if(!isset($_POST['submit'])) {
header("Location: ../../index");
return;
} else {
$user = $db->escapestring($_POST['user']);
$pass = $db->escapestring($_POST['pass']);
if (empty($user) || empty($pass)) {
$_SESSION['logError'] = "Both fields must be filled!";
header("Location: ../../index");
return;
} else {
$result = $db->query("SELECT * FROM users WHERE username = '$user'");
$result = $db->getrows($result);
if ($result < 1) {
$_SESSION['logError'] = "Username does not exist!";
header("Location: ../../index");
return;
} else {
$pass = md5($pass);
$result = $db->query("SELECT * FROM users WHERE username = '$user' AND password = '$pass'");
$result = $db->getrows($result);
if ($result < 1) {
$_SESSION['logError'] = "Details do not match!";
header("Location: ../../index");
return;
} else {
$result = $db->query("SELECT * FROM users WHERE username = '$user' AND password = '$pass'");
while($row = $result->fetch_assoc()){
$username = $row['username'];
$id = $row['id'];
}
$user->buildUserData($id);
$_SESSION['logError'] = "Hello ". $user->username;
header("Location: ../../index");
return;
}
}
}
}
?>
This is the global.php code
<?php
session_start();
require_once 'cfgs/class.database.php';
require_once 'cfgs/class.user.php';
$user = new userData; // I don't want to build data just yet
$db = new database;
$db->conn = $db->connect();
?>
And finally my database handler
<?php
class database {
public $host = "_";
public $user = "_";
public $pass = "_";
public $db = "_";
public $conn = null;
function connect() {
return mysqli_connect($this->host, $this->user, $this->pass, $this->db);
}
function query($sql) {
return mysqli_query($this->conn, $sql);
}
function escapestring($string){
return mysqli_real_escape_string($this->conn, $string);
}
function getrows($sql){
return mysqli_num_rows($sql);
}
}
?>
I did search for a solution myself but it turns out to be one of those specific things that is difficult to find the answer you're looking for.

Answer 1

while you initialise $user just fine:
$user = new userData;
you later overwrite the variable:
$user = $db->escapestring($_POST['user']);
one of the 2 needs a new name,