Question

Sup! We have core class with mysql connection, than we include plugin and we need that plugin cant access to our DB without core class methods.

index.php

<?php
    class Core
    {
        function connect()
        {
            $db = @mysql_connect($host, $user, $pass);
            @mysql_select_db($base, $db);
        }

        function query($sql)
        {
            return mysql_query($sql);
        }
    }

    global $c;
    $c = new Core();

    include('plugin.php');
    $p = new Plugin();
    echo $p->not_work_connection();
    echo $p->work_connection();
?>

plugin.php

<?php
    class Plugin
    {
        function not_work_connection()
        {
            $sql = 'SELECT * FROM `net_country` LIMIT 0 , 1';
            $result = mysql_query($sql); 
            while($row = mysql_fetch_array($result, MYSQL_ASSOC)) 
            {
                return print_r($row, 1);
            }
        }

        function work_connection()
        {
        global $c;
            $result =$c->query('SELECT * FROM `net_country` LIMIT 0 , 1'); 
            while($row = mysql_fetch_array($result, MYSQL_ASSOC)) 
            {
                return print_r($row, 1); 
            }
        }
    }
?>

I need restrict access from included scripts, but thay can use core methods to make queries. How i can make it?

Answer 1

mysql_query without the second param uses the last link used by mysql_connect, so you could create a dummy connection after the real one :

<?php
class Core
{
    private $db;
    function connect()
    {
        $this->db = @mysql_connect($host, $user, $pass);
        @mysql_select_db($base, $db);

        //dummy 
        @mysql_connect();
    }

    function query($sql)
    {
        //notice second param
        return mysql_query($sql, $this->db);
    }
}

global $c;
$c = new Core();

include('plugin.php');
$p = new Plugin();
echo $p->not_work_connection(); //doing a mysql_query will use the dummy resource and fail
echo $p->work_connection();
?>