Upgrade from mysql_connect() to mysqli_connect() - handle port number and socket.

db.php

// These are examples of MySQL host names that will work fine in mysql_connect() but fail in mysqli_connect()
// If you are upgrading an old script to mysqli the client may have configured these as values for their database server.
// The below script parses out port number or socket and translates that into a correct mysqli_connect() call.
define('_DB_SERVER', '1.2.3.4:3306');
define('_DB_SERVER', '1.2.3.4:/tmp/socket4');

if(function_exists('mysqli_connect')){
	$server = _DB_SERVER;
	$port_number = null;
	$socket = null;
	if(preg_match('#:(\d+)$#',$server,$matches)){
		$server = str_replace(':'.$matches[1], '', $server);
		$port_number = $matches[1];
	}
	if(preg_match('#:([/\w]+)$#',$server,$matches)){
		$server = str_replace(':'.$matches[1], '', $server);
		$socket = $matches[1];
	}
	self::$dbcnx = mysqli_connect($server,_DB_USER,_DB_PASS, _DB_NAME, $port_number, $socket);
	if (mysqli_connect_errno()) {
		printf("Connect failed: %s\n", mysqli_connect_error());
		exit();
	}
}else{
	mysql_connect(_DB_SERVER,_DB_USER,_DB_PASS) or die(mysql_error());
}