db.php

<?php
require_once dirname(__FILE__) . "/modules/HttpException/HttpException.php";
require_once dirname(__FILE__) . "/config/database.php"; # import database settings

final class proxy_mysqli extends mysqli {
	public function query($db_query, $resultmode = MYSQLI_STORE_RESULT, $msg = '') {
		$db_result = parent::query($db_query, $resultmode);
		if ($db_result === FALSE) {
			throw new HttpException(500, ($msg ? $msg . ': ' : '') . $this->error);
		}
		return $db_result;
	}
}

function db_ensure_connection()
{
	static $connection = false;

	if (!$connection)
	{
		$connection = new proxy_mysqli(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
		if ($connection->connect_error || mysqli_connect_error() || $connection->error)
		{
			throw new HttpException(500);
		}
		$connection->set_charset('latin1');
	}
	return $connection;
}
?>