/**
 * will read data from the socket. Since we are using non blocking 
 * mode, if we attempt to read the data even a millisecond before 
 * it becomes available, the method just returns null.
 *
 * So what's the cure? we will loop for a while and try to read it
 * in multiple times. Note that if we used blocking mode there may
 * be instances when this function NEVER returns.
*/
function sock_read($i=0)
{
	/*
	 * global variables are lame, we will create a class in the
	 * next step
	 */
	global $sock; 
	$s = fgets($sock);
	if($s=='')
	{
		if($i==30)
		{
			break;
		}
		else
		{
			sleep(1);
			return sock_read($i+1);
		}
	}
	return $s;
}

function is_ok()
{
	$s = sock_read();

	if($s == "" || preg_match('/^5/',$s) )
	{
		return 0;
	}
	else
	{
		return 1;
	}

}

function sock_write($s)
{
	global $sock;
	echo "< $s\n";
	fputs($sock,"$s\n");
}

	$sock = fsockopen("localhost",21,&$errno,&$errstr,30);
	set_socket_blocking($sock,false);
	if($sock)
	{
		if(is_ok())
		{
			sock_write("user imapuser");

			if(is_ok())
			{
				sock_write("pass 123");
				is_ok();
			}
		}
	}