Register user PHP - php

Question

I am trying to create a PHP script to register users. It connects my xCode with a mySQL database.
I am getting the following error:
8ee52684907bd42381d94f74f3c4d321b17c5285 Notice: Trying to get
property of non-object in
/Applications/XAMPP/xamppfiles/htdocs/SwiftAppAndMYSQL/db/MySQLDAO.php
on line 76
Fatal error: Uncaught exception 'Exception' in
/Applications/XAMPP/xamppfiles/htdocs/SwiftAppAndMYSQL/db/MySQLDAO.php:76
Stack trace: #0
/Applications/XAMPP/xamppfiles/htdocs/SwiftAppAndMYSQL/scripts/registerUser.php(63):
MySQLDAO->registerUser('email', 'gui', 'Maia', '8ee52684907bd42...',
'\x99\x99S'eXqs\xE0\xC4\x80[\xB1\x07y...') #1 {main} thrown in
/Applications/XAMPP/xamppfiles/htdocs/SwiftAppAndMYSQL/db/MySQLDAO.php
on line 76
This is my registerUser script
<?php
require ("../db/MySQLDAO.php");
require ("../db/Conn.php");
$returnValue = array();
if (
empty($_REQUEST["userEmail"]) ||
empty($_REQUEST["userPassword"]) ||
empty($_REQUEST["userFirstName"]) ||
empty($_REQUEST["userLastName"])) {
$returnValue["status"] = "400";
$returnValue["message"] = "Missing required information";
echo json_encode($returnValue);
return;
}
$userEmail = htmlentities($_REQUEST["userEmail"]);
$userPassword = htmlentities($_REQUEST["userPassword"]);
$userFirstName = htmlentities($_REQUEST["userFirstName"]);
$userLastName = htmlentities($_REQUEST["userLastName"]);
$salt = openssl_random_pseudo_bytes(16);
$secure_password = sha1($userPassword . $salt);
echo $secure_password;
$dao = new MySQLDAO(Conn::$dbhost, Conn::$dbuser, Conn::$dbpass, Conn::$dbname);
$dao->openConnection();
$userDetails = $dao->getUserDetails($userEmail);
if(!empty($userDetails))
{
$returnValue["status"] = "400";
$returnValue["message"] = "Please choose different email address";
echo json_encode($returnValue);
return;
}
$result = $dao->registerUser($userEmail, $userFirstName, $userLastName, $secure_password, $salt);
if ($result) {
$userDetails = $dao->getUserDetails($userEmail);
$returnValue["status"] = "200";
$returnValue["message"] = "Sucessfully registered new user";
$returnValue["userId"] = $userDetails["user_id"];
$returnValue["userFirstName"] = $userDetails["first_name"];
$returnValue["userLastName"] = $userDetails["last_name"];
$returnValue["userEmail"] = $userDetails["email"];
} else {
$returnValue["status"] = "400";
$returnValue["message"] = "Could not register user with provided information";
}
$dao->closeConnection();
echo json_encode($returnValue);
?>
My DAO object goes bellow:
<?php
class MySQLDAO {
private $dbpassword;
var $dbhost = null;
var $dbuser = null;
var $dbpass = null;
var $conn = null;
var $dbname = null;
var $result = null;
function __construct($dbhost, $dbuser, $dbpassword, $dbname) {
$this->dbhost = $dbhost;
$this->dbuser = $dbuser;
$this->dbpass = $dbpassword;
$this->dbname = $dbname;
}
public function openConnection() {
$this->conn = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
if (mysqli_connect_error())
throw new Exception("Could not stabilish connection with database");
$this->conn->set_charset("utf8");
}
public function closeConnection() {
if ($this->conn != null)
$this->conn->close();
}
public function getUserDetails($email){
$returnValue = array();
$sql = "select * from users where email= '".$email."'";
$result = $this->conn->query($sql);
if ($result != null && (mysqli_num_rows($result) >= 1 )){
$row = $result->fetch_array(MYSQLI_ASSOC);
if (!empty($row)){
$returnValue = $row;
}
}
return $returnValue;
}
public function registerUser($email, $first_name, $last_name, $password, $salt) {
$sql = "insert unto users set email=?, first_name=?, last_name=?, user_password=?, salt=?";
$statement = $this->conn->prepare($sql);
if (!$statement){
throw new Exception($statement->error);
}
$statement->bind_param("sssss", $email, $first_name, $last_name, $password, $salt);
$returnValue = $statement->execute();
return $returnValue;
}
}
My connection class
<?php
class Conn {
public static $dbhost = "localhost";
public static $dbuser = "root";
public static $dbpass = "";
public static $dbname = "SwiftApp";
}
?>

Answer 1

There is one possible error I can spot:
This SQL query has a typo, it should be into, not unto, resulting in a syntax error:
$sql = "insert unto users set email=?, first_name=?, last_name=?, user_password=?, salt=?";
$statement = $this->conn->prepare($sql);
The syntax error results in $mysqli->prepare() returning false.
If this is the case the next block can't work.
if (!$statement){
throw new Exception($statement->error);
}
If $statement is false, it isn't an object, so $statement->error doesn't work and the error Trying to get property of non-object is thrown.
This should report the desired result:
/// corrected query
$sql = "insert into users set email=?, first_name=?, last_name=?, user_password=?, salt=?";
$statement = $this->conn->prepare($sql);
if (!$statement){
/// corrected error reporting
throw new Exception($this->conn->error);
}