Question

I little while back I posted this question. I have updated that question with the AJAX script that worked for about 1 week. Basically I can use session_start() from the AJAX script, and then I could access the session variables that I needed.

It is really strange, but I came in after the weekend, and this morning this script does not work anymore. It is very simple, here:

<?php

session_start();

$ajax_connection = mysql_connect('10.X.X.X',$_SESSION['username'],$_SESSION['password']);

$result_set = array();

while ($result_set[] = mysql_fetch_assoc($results)){
    // do nothing
}

echo json_encode($results);

?>

Last week this worked flawlessly, and now in my error log i get the Undefined index: username and Undefined index: password warnings. And of course the MySQL connection is not established. So this script is not running the same session as the original connection. I used error_log(session_id()) to check the IDs of the parent page and the AJAX script, and sure enough they are different. When i reload the page and try every again, the IDs stay the same for the page and the AJAX script respectively, but they should be the same ID, not 2 different ones.

Anyway, does anyone have any idea why this wouldn’t be working anymore, after working well for over a week?

Answer 1

Here’s the kind of Class you can use. It is in singleton to make sure you instanciate it only once. Instanciate it with

$db = Db::getInstance();

then

$db->connect();

this is a much safer way to use Dbase connections (Note that I used PDO, but if you really need to keep using mysql_ functions, you can still modify it).

class Db {

    private static $instance = null;
    private $db = null;
    private $host = '';
    private $name = '';
    private $username = '';
    private $password = '';

    private function __construct() {
        $this->host = 'yourHost';
        $this->name = 'yourDbName';
        $this->username = 'yourUserName';
        $this->password = 'youPassword';
    }

    public static function getInstance() {
        if(is_null(self::$instance)) {
            self::$instance = new Db();
        }
        return self::$instance;
     }

     public function connect() {
        try {
            $this->db = new PDO('mysql:host=' . $this->host . ';dbname=' . $this->name, $this->username, $this->password);
        } catch(Exception $e) {
            throw new Exception('Connection error: either the database is unavailable or connection infos are not valid. Please contact the webmaster.');
        }
    }
}