[SOLVED] Need help `encapsulating` database connection resource

[Andy-H]

<?php

require_once "constants/dbInfo.const.php";

class db
{

private        $conn;
private static $instance;

 private function __CONSTRUCT()
 {
  
 	$conn = mysql_connect( HOST, USER, PASS ) or trigger_error( 'Couldn\'t connect to mysql', E_USER_ERROR );
 	$db   = mysql_select_db( DB, $conn )or trigger_error( 'Couldn\'t select requested database', E_USER_ERROR );
  
 		$this->conn = $conn;

 }

 	static function instance()
 	{
 		if ( !isSet( self::$instance ) )
 			self::$instance = new self();

 		return self::$instance;

        }

 		public function cleanStr( $str, $args )
 		{
 			if ( !is_array($args) || empty($args) )
 				return false;

 				forEach( $args AS $k => $v )
 				{

 					if ( is_string( $v ) )
 					{
 					 
 						if ( substr( $v, 0, 6 ) == 'clean:' )
 						$args[$k] = mysql_real_escape_string( substr( $v, 6 ), $this->conn );
 					}
 				}

 				return vsprintf( $str, $args );
 		}

 			public function query( $str )
 			{
 				 
 				return mysql_query( $str, $this->conn );

 			}

 				public function arr( $result, $type = MYSQL_NUM )
 				{

 					return mysql_fetch_array( $result, $type );

 				}

 				public function obj( $result )
 				{

 					return mysql_fetch_object( $result );

 				}

}

?>

 

I have made the above class in an attempt to learn about OOP in PHP, I would like to (and intended to) make it so that the link to the database could only be accessed via the classes methods. 

 

However, when I run the following piece of code I can call mysql_query etc... without having to go through the classes methods.

 

<?php
error_reporting(E_ALL);
require_once "../class/connections/dataBase.inc.php";

db::instance();

$query = "SELECT user FROM users WHERE id = 1 LIMIT 1";
$result= mysql_query($query)or trigger_error(mysql_error());
$row   = mysql_fetch_row($result);

echo $row[0] . "<br >\n";

$arr[] = 'clean:Andy';
$arr[] = 1;

$query  = db::instance()->cleanStr( "SELECT user FROM users WHERE user = '%s' AND id = %d ", $arr );
$result = db::instance()->query( $query );
$row    = db::instance()->obj( $result );

echo $row->user;

?>

 

This outputs 

Andy<br >
Andy

 

 

Is there any way I can make the connection only accessible via the class?

 

Thanks.

[Mark Baker]

It all comes down to the optional link_identifier parameter for mysql_query() et al.

If no value is specified for the parameter, then the value will default to the last link opened by a mysql_connect.

 

If you really need to suppress this behaviour, you could try opening and then closing a second link within your db::instance() method (without saving it in $db->conn). This would then become the default for the link_identifier parameter for mysql_query(), but as it has since been closed it would result in an error when trying to use mysql_query().

Note that your own queries being issued through the db class would need to specify the $db->conn value as the link_identifier parameter.

[MadTechie]

I'm not sure if Mark is on the right track, but the problem is that once a connection is open, mysql_query is finds it with or without the link,

 

so any mysql_query after db::instance(); will work,

 

I guess opening the connection on use and then closing the connection after would work! but isn't ideal!

[Andy-H]

Ahh ok, thanks. Ill just leave the link open and edit my cleanStr() method lol.

 

I assumed I wouldnt be able to call mysql_real_escape_string outside of the class, wont be needing it now anyhow lol

 

Thanks for the help

[MadTechie]

Okay i was just thinking about the logic, the mysql_query will use the last "active" connection, if link is not set..

 

Soooo... maybe add

mysql_connect();

right after

$this->conn = $conn;

this will be used any anything that doesn't use the link and will fail as theirs no database selected..

its worth a try

[Andy-H]

Wont that throw an error?

[MadTechie]

you can still pass the username and password.. just open another connection with mysql_connect();