if ( ! preg_match("/^[a-z0-9:_\/-]+$|/i", $str))
{
exit('Disallowed Key Characters.'. $str);
}
$_config[0] =& $config; return $_config[0];

Monolog supports the logging levels described by RFC 5424.
DEBUG (100): Detailed debug information.
INFO (200): Interesting events. Examples: User logs in, SQL logs.
NOTICE (250): Normal but significant events.
WARNING (300): Exceptional occurrences that are not errors. Examples: Use of deprecated APIs, poor use of an API, undesirable things that are not necessarily wrong.
ERROR (400): Runtime errors that do not require immediate action but should typically be logged and monitored.
CRITICAL (500): Critical conditions. Example: Application component unavailable, unexpected exception.
ALERT (550): Action must be taken immediately. Example: Entire website down, database unavailable, etc. This should trigger the SMS alerts and wake you up.
EMERGENCY (600): Emergency: system is unusable.
The Joel Test
if(!preg_match('/^[0-9a-zA-Z]([\-.\w]*[0-9a-zA-Z\-_+])*@([0-9a-zA-Z][\-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9}$/', $email))
{
// 통과못했을경우
}