Authenticate OpenVPN against a DB, with Bcrypt hashed passwords

OpenVPN_DBAuth.php

<?php
if (!isset($argv[1]))
	{
	print 'not ok';
	exit(1);
	}
	
$data = file($argv[1], FILE_IGNORE_NEW_LINES);
// Add your [address], [dbuser], [pass], [database]
$conn = new mysqli("127.0.0.1", "root", "password", "openvpn");
if ($conn->connect_error) // maybe remove this when you have the script setup
{
    die("Connection failed: " . $conn->connect_error);
}
// Create  db named openvpn and a table named users
// Then add two columns, one named password and another named user
// populate them with [username], [bcrypt-hashed-pass]
$stmt = $conn->prepare("SELECT password FROM users WHERE user = ?");
$stmt->bind_param("s", $data[0]);
$stmt->execute();
$result = $stmt->get_result()->fetch_assoc();
if (!$result) { echo 'not ok'; exit(1); } // User non-existent
if (password_verify($data[1], $result['password']))
{
	echo 'ok';
	exit(0);
}
else
{
	echo 'not ok';
	exit(1);
}
?>