How do I fix this code (due to MySql deprecated) - php

Question

So I have written this login system, but there is one big problem. Everytime I try to get the $errors to print when the values inputted are contradictory to the code, it doesn't work. This is the user login code
<?php
if (empty($_POST) === false) {
$username = $_POST['username'];
$password = $_POST['password'];
if (empty($username) === true || empty($password) === true) {
$errors[] = 'Fill out this field!';
} else if (user_exists($username) === false) {
$errors[] = 'Are you sure you\'ve registered?';
} else if (user_active($username) === false) {
$errors[] = 'you haven\'t activated your account!';
} else {
//Login com.
}
print_r($errors);
}
?>
So I don't see any problems here. Where I suspect problems to be are here. This is the general file:
<?php
function sanitize($data) {
return mysqli_real_escape_string($data);
}
?>
and here is the users code:
<?php
function user_active($username, $con){
$username = sanitize($username, $con);
$q = "SELECT COUNT(`user_id`)
FROM `users`
WHERE `username` = '{$username}'
AND `active` = 1";
if($query = mysqli_query($con, $q)){
return (mysqli_num_rows($query) > 0) ? true : false;
} else {
//TODO: Replace in production
trigger_error('<p>Query ' . mysqli_error($con) . '</p>');
}
}
?>
This is the connect code:
<?php
$con = mysqli_connect('localhost', 'root', '') or die(mysql_error());
mysqli_select_db($con, 'users');
?>
I know that MySql is deprecated so I converted to MySqli but it just caused more problems as the codes kept contradicting each other. Any help would be appreciated. Thank you!

Answer 1

Modify like this,
<?php
function sanitize($data, $con) { //$con parameter added
return mysqli_real_escape_string($con, $data); //$con parameter added
}
?>
Read out here