I need patern to validate a concret string

Question

I need a function to validate any string provided in GET['date'] parameter.

The function will return true if the string provided is in format "j-n-Y", and is a date between today and the future.

Examples:

http://mysite.org/index.php?date=iwhechiuhwe will return false.

http://mysite.org/index.php?date=13-5-2017 will return true.

http://mysite.org/index.php?date=13-5-2010 will return false.

http://mysite.org/index.php?date=19-5-2014 will return true.

Answer 1

$dateResult = DateTime::createFromFormat('j-n-Y', $_GET['date']);

This method in PHP's DateTime class returns false if it couldn't create a date object from the requested format and given string.

A further test to verify that the given date was today or future (if $dateResult is not already false):

$now = strtotime('Y-m-d', time());
$isValid = $dateResult->getTimestamp() >= $now;